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Economic geology of the heavy mineral placer deposits in northeastern Florida /

HIDE
 Title Page
 Foreword
 Table of Contents
 List of Illustrations
 List of Tables
 Acknowledgement
 Abstract
 Introduction
 Economic geology of the heavy mineral...
 History and future of heavy mineral...
 Geologic summary and economic...
 Bibliography
 Appendices
FGS
Permanent Link: http://ufdc.ufl.edu/UF00099441/00001

Material Information

Title: Economic geology of the heavy mineral placer deposits in northeastern Florida /
Physical Description: vii, 98, 32 p. : ill., maps ; 28 cm.
Language: English
Creator: Elsner, Harald
Publisher: Florida Geological Survey
Place of Publication: Tallahassee, Fla.
Publication Date: 1997

Subjects

Subjects / Keywords: Placer deposits -- Florida   ( lcsh )
Geology, Economic -- Florida   ( lcsh )
Heavy minerals -- Prospecting -- Florida   ( lcsh )
Genre: bibliography   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography: Includes bibliographical references (p. 58-74).
General Note: Florida Geological Survey open file report 71
Statement of Responsibility: Harald Elsner.

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier: oclc - 37564699
issn - 1058-1391 ;
Classification:
System ID: UF00099441:00001

Permanent Link: http://ufdc.ufl.edu/UF00099441/00001

Material Information

Title: Economic geology of the heavy mineral placer deposits in northeastern Florida /
Physical Description: vii, 98, 32 p. : ill., maps ; 28 cm.
Language: English
Creator: Elsner, Harald
Publisher: Florida Geological Survey
Place of Publication: Tallahassee, Fla.
Publication Date: 1997

Subjects

Subjects / Keywords: Placer deposits -- Florida   ( lcsh )
Geology, Economic -- Florida   ( lcsh )
Heavy minerals -- Prospecting -- Florida   ( lcsh )
Genre: bibliography   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography: Includes bibliographical references (p. 58-74).
General Note: Florida Geological Survey open file report 71
Statement of Responsibility: Harald Elsner.

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier: oclc - 37564699
issn - 1058-1391 ;
Classification:
System ID: UF00099441:00001

Table of Contents
    Title Page
        Title Page 1
        Title Page 2
    Foreword
        Page i
        Page ii
    Table of Contents
        Page iii
    List of Illustrations
        Page iv
    List of Tables
        Page v
        Page vi
    Acknowledgement
        Page vii
        Page viii
    Abstract
        Page 1
        Page 2
        Page 3
    Introduction
        Page 4
        Page 5
        Page 6
    Economic geology of the heavy mineral placer deposits in northeastern Florida
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
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        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
    History and future of heavy mineral mining in northeastern Florida
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
    Geologic summary and economic conclusion
        Page 56
        Page 57
    Bibliography
        Page 58
        Page 59
        Page 60
        Page 61
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    Appendices
        Page 74
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Full Text




STATE OF FLORIDA
DEPARTMENT OF ENVIRONMENTAL PROTECTION
Virginia B. Wetherell, Secretary






DIVISION OF ADMINISTRATIVE & TECHNICAL SERVICES
Nevin G. Smith, Director





FLORIDA GEOLOGICAL SURVEY
Walter Schmidt, State Geologist and Chi'ef




OPEN FILE REPORT NO. 71

ECONOMIC GEOLOGY OF THE HEAVY MINERAL PLACER DEPOSITS
IN NORTHEASTERN FLORIDA



by

Harald Elsner


FLORIDA GEOLOGICAL SURVEY
TALLAHASSEE
1997


ISSN 1058-1391


0JNIVE.RSITY OiF FLO il~A LDRARI~ES







































$CIENCE:
LIBRAR.I:















July 1997


This report is being made a part of the Florida Geological Survey
(FGS), Open File Report Series to provide access by interested
professional and the public. It has not been reformatted according
to FGS standards or edited for content accuracy.

It is, however, being made available, because it is a valuable
contribution to the study and understanding of Florida's Heavy
Mineral deposits.

Sincerely,



Walter Schmidt, Ph.D.
State Geologist and Chief
Florida Geological Survey

































Printed by the
Florida Geological Survey
Division of Administrative & Technical Services
Florida Department of Environmental Protection

Tallahassee
1997










CONTENTS



Page

Ac kno wledgements .......................................................................... IX

A b stract ......................................... .. ... .. ..... .. .... ...... .... ... .. ..... ... .. 1

Introduction............................. .. ... ........ ... ... ........ .. ..... .... ... ... .. 4

Economic geology of the heavy mineral placer deposits in northeastern Florida.......... 7

Tra il Ridge ............................................................................................. 7

Fol kston ............................................................................................... 13

Boulo gne ....................................................................... ..........,..................................... 18

Green Cov eSprings ..................................................................................... 2 1

J acksonville ............................................................................................ 2 7

Yulee .....................................;............................................................33

Amelia Is land ........................................................................................ 37

Little Talbot Is land ...................................................................................... 3 9

Ponte Vedra Beach (Mineral Cit y) .......................................................................... 4 1

Offs here ........................................................................................... 4 4

History and future of heavy mineral mining in northeastern Florida ............................. 48

Geologic summary and economic conclusion .................................................... 56

Selected biblio graph y.................................................................. 5 8

Appendices ................................................................................ 74

Appendix I: Or ig in of an al yzed samp le s.................................................................. 7 4

Appendix II: Characteristics of heavy mineral samples ..........................................................75

Ilmenite and leucox ene............................................................................... 7 6
Trail Ridge:................................... ............................ ............76
Folkston: .......................................... .. ............................ ............ 77
Green Cove Springs: .................... .............................................. .. ............78
B oulogne:....................................................................... ........... 78
Jacksonville:.................................................................................... 78

Rutile ................................................................................................. 8 2
Jacksonville:. ... ..... .... ........... .............. .. ...... .. .. ................................. 82
Green Cove Springs: ...................................................... ..... .. ....... ... ........ ... 82

Z ircon ................................................................................................ 8 5
Green Cove Sp rin gs: .................................................................................... 8 5
Trail Ridge: .............................................. ............... .......... ............ 86
Folkston: ......................................................................... .. ............ 86
B oulogne:............................................................................................. 87
Jacksonville: ...................................................................... .. ............ 87

M onaz ite and xenotime ................................................................................... 90
Boulogne: ................................................. ..... .......... ...... .... ............ 90
Jacksonville:................................ .......... ........ ........ ... .. .. ............ 90
Folkston: ............................................................................................. 90

Green Cove Springs: ...................................................... ... .. ... ............ 91

Staurolite .............................................................................................. 9 3
Green Cove Springs: .................................. .. ... .... ....... ................ 93
Trail Ridge: ......................................... ........... .. .. ...... .. .. ....... ... ....93

Garne t, ky anit e, sillimanite ............................................................................... 9 6




iii








Illustrations


Figure
1 Map of h. m. placer deposits in northeastern Florida
2 Lithology, grain size variations, and mineralogical suite in core Trail Ridge 1
3 Lithology, grain size variations, and mineralogical suite in core Trail Ridge 2
4 Lithology, grain size variations, and mineralogical suite in core Highland 1
5 Lithology, grain size variations, and mineralogical suite in core Highland 2
6 Lithology, grain size variations, and mineralogical suite in core Trail Ridge 3
7 Average h. m. composition of ore sands in cores Trail Ridge 1, Trail Ridge 2, Highland 1,
Highland 2, and Trail Ridge 3 (from south to north)
8 Map of the Trail Ridge h. m. placer deposit
9 Flow diagram showing the separation of h. m. at Trail Ridge by Du Pont
10 Map of the Folkston h. m. placer deposit
11 Flow diagram showing the separation of h. m. at Folkston by Humphreys Gold Corpora-
tron
12 Map of the Boulogne h. m. placer deposit
13 Distribution of h. m. placer deposits in the Folkston-Boulogne placer district and the areas
of radioactivity anomalies
14 Average h. m. composition of ore sands in core Boulogne 1 and from the Folkston h. m.
placer deposit
15 Lithology, grain size variations, and mineralogical suite in core Boulogne 1
16 Map of the Green Cove Springs h. m. placer deposit
17 Lithology, grain size variations, and mineralogical suite in core Union Camp 1
18 Lithology, grain size variations, and mineralogical suite in core Union Camp 2
19 Average h. m. composition of ore sands in cores Union Camp 1, and Union Camp 2
(Green Cove Springs main ore body) as well as of a typical sample of ore sand from the
Green Cove Springs western ore body
20 Map of the Jacksonville h. m. placer deposit
21 Cross-sections through the Skinner tract of the Jacksonville h. m. placer deposit
22 Map of the Yulee h. m. placer deposit
23 Map of Amelia Island
24 Map of Little and Big Talbot Islands
25 Average h. m. composition of dune and beach sands of Little Talbot Island
26 Time tableof h. m. mining operations in Florida
27 Proposed target areas for future exploration for h. m. in northeastern Florida
28 Map of northeastern Florida showing locations of well cores stored in the Florida Geo-
logical Survey core library










Table
1 Relative share of the most important nations in the production of some h. m. after various
authors
2 United States system of measurement conversion factors
3 Average composition of h. m. concentrates of the Trail Ridge placer deposit after various
authors
4 H. m. composition of ore sands of the Folkston placer deposit (main area)
5 Planned and achieved production, and recalculation of original reserve base of the Folk-
ston placer deposit (main area)
6 Economic geology of the ,,west" and ,,north extensions" of the Folkston placer deposit
and assumed total original reserve base of the Folkston placer district
7 Original reserve base of the Boulogne placer deposit and production data of the area
mined between 1974 to 1979 (after Humphreys Mining Company, 1980)
8 Average h. m. grade and composition of the Boulogne and Green Cove Springs placer
deposits (after Elsner 1992 b)
9 Average h. m. composition of the Green Cove Springs main ore body after Pirkle et al.
(1991) and Elsner (1992 a)
10 H. m. concentration of sands in cores Union Camp 1, Union Camp 2, and Union Camp 3
(Green Cove Springs main ore body) after Pirkle et al. (1991) and Elsner (1992 a)
11 Economic geology of the Green Cove Springs placer deposit
12 Average h m. composition of ore sands and of a wet mill concentrate of the Jacksonville
placer deposit after various authors
13 Average h. m. composition of the Jacksonville placer deposit
14 Economic geology of the Jacksonville placer deposit
15 Average h.m. composition of the Yulee placer deposit after various authors
16 Economic geology of the Yulee placer deposit
17 Average h. m. composition and grade of sands of different areas of Amelia Island after
various authors
18 Average h. m. composition and grade of sands of Little and Big Talbot Islands after Pey-
ton (1955) and Eichenholtz (1989)
19 Economic geology of coastal placer deposits along the Recent Atlantic coast between
Jacksonville Beach and Vilano Beach
20 Important economic data of h. m. mining in Florida
21 Sediment parameters of sands of well Scott # 2
22 Economic parameters of h. m. placer deposits in northeastern Florida
23 Economic parameters of selected h. m. placer deposits outside the USA after various
authors
24 Key parameters of well cores of northeastern Florida stored in the core library of the
Florida Geological Survey
25 Conversion table of sieve sizes
26 Chemical composition of Trail Ridge ilmenite after various authors
27 Chemical composition of Trail Ridge residue after various authors
28 Chemical composition ofJacksonville ilmenite after various authors
29 Geochemical composition of ilmenite and leucoxene concentrates produced in northeast-
ern Florida
30 Mineralogical and granulometric composition of ilmenite and leucoxene concentrates pro-
duced in northeastern Florida
31 Chemical composition ofJacksonville rutile after various authors
32 Geochemical composition of rutile concentrates produced in northeastern Florida


Tables







33 Mineralogical and granulometric composition of rutile concentrates produced in north-
eastern Florida
34 Typical specifications of commercial zircon concentrates, after Coope (1987), Clarke
(1987), and an unpublished note of HGC
35 Geochemical composition of zircon concentrates produced in northeastern Florida
36 Mineralogical and granulometric composition of zircon concentrates produced in north-
eastern Florida
37 Composition of the REO-fraction of monazite concentrates produced in northeastern
Florida (converted to 100 % REO)
38 Mineralogical and granulometric composition of monazite concentrates produced in
northeastern Florida
39 Mean grain size of Trail Ridge staurolite concentrates after various authors
40 Average mineralogical and granulometric composition of Trail Ridge staurolite concen-
trates after various authors
41 Geochemical composition of staurolite concentrates produced in northeastern Florida
42 Mineralogical and granulometric composition of staurolite concentrates produced in
northeastern Florida
43 Geochemical composition of garnet and aluminium-silicates concentrates produced in
northeastern Florida
44 Mineralogical and granulometric composition of garnet and aluminium-silicates concen-
trates produced in northeastern Florida







A4ckn ow led gem en ts

I would like to thank my two major professors,
* Prof. Dr. D. Henningsen, Department of Geology, University of Hannover, Germany
* Dr. W. F. Tanner, Regents Professor, Department of Geology, Florida State University,
Tallahassee, FL,
for their help with the preparations for the original work, their personal support with the plan-
ning and realization of my stays in Florida, and their sharing of knowledge about the granulo-
metric and heavy mineral analyses. Above all I am most grateful for the numerous discussions
which contributed to the dissertation from the first ideas to its completion.

The original Ph. D. dissertation would not have been possible without substantial help
from many people. This help included discussions, plant tours, provision of heavy mineral sam-
ples, the passing-on of company reports, material technical support, practical personal help in
Florida, analyses of all sorts, translations and, very important, the sharing of life-long experi-
ence. The hearty welcome by a number of people in Florida is something I will always remem-
ber.

Gratitude is expressed to:
* Dr. W. F. Tanner, Dr. J. K. Osmond, Dr. S. A. Kish, Dr. F. Rizk, Dr. P. Lee, Dr. Joe
Aylor, Gabrielle Lee, Will Evans, Katherine Milla, Dennis Cassidy
(Department of Geology, FSU)
* Prof. Dr. D. Henningsen, Prof. Dr. R. Fischer, Werner Bartholom~us, Matthias Winter
(Department of Geology, University of Hannover)
* Prof. Dr. E. Eberhard (Department of Mineralogy, University of Hannover)
* Prof. Dr. J. F. W. Negendank (Department of Geology, University of Trier)
* Thomas Raudaschl (Department of Physics, Technical University of Munich)
* Dr. E. C. Pirkle (Department of Geology, University of Florida, Gainesville)
* Dr. S. C. Porter (Quaternary Research Center, University of Washington, Seattle)
* Prof. Dr. B. Urban (University of Northeast Lower-Saxony, Suderburg)
* Dr. P. Simon, Dr. E. Hofmeister, Dr. K.- D. Meyer, Dr. K.- J. Meyer, Dr. W. Knabe, Dr.
H.- R. Kudrass, XRF- Lab team
(Geological Survey of Lower Saxony / Geological Survey of Germany, Hannover)
* Dr. T. M. (Tom) Scott, Frank Rupert, Ken Campbell
(Florida Geological Survey, Tallahassee)
* Dr. A. E. (Andrew) Grosz (a), Dr. E. R. (Eric) Force (b)
(United States Geological Survey, Reston, VA (a), Tucson, AZ (b))
* T. E. (Tom) Garnar, Jr. (Titanium Consultants Inc., Keystone Heights, FL)
* E. V. (Gene) Whittle, John Gully (formerly Humphreys Mining Company)
* Dr. F. L. (Fred) Pirkle, J. G. (Jack) Reynolds, N. W. (Norm) Stouffer
(E. I. Du Pont de Nemours & Company, Inc., Starke, FL)
* S. K. (Steve) Gilman, Frank Russell, Doug Miller
(Renison Goldfields Consolidated (USA) Inc., Green Cove Springs, FL)
* S. B. (Steve) Hearn, Clyde Webb, R. M. Carver (Carpco, Inc., Jacksonville, FL)
* Dr. J. Luck (Spectro Analytical Instruments, Kleve, Germany)

My studies at the Florida State University were strongly financially supported by two
grants of the German Academic Exchange Service.
Printing of this English translation of the economic part of the original German Ph. D.
dissertation was made possible by the staff and the administration of the Florida Geological
Survey.
vii








Abstract


Heavy mineral players have been mined in northeastern Florida for several decades.
Although decreasing in importance, Florida still has a considerable share. in the world produc-
tion of ilmenite, rutile, zircon, and monazite.

To obtain information about the geology of these heavy mineral players more than 230
laminar sand samples were taken from cores and in the field.
Granulometric analyses included dry-sieving in a nest of sieves and calculation of mo-
ment measures of weighed sand fractions. Suite statistics were successfully used to determine
depositional environments of the various players and underlying formations.
Smaller samples of the same stratigraphic horizons were checked for their heavy min-
eral composition and their total heavy mineral content in weight-percentages. Several hundred
grains each of the magnetic and non-magnetic fractions were determined under the micro-
scope. Heavy minerals of northeastern Florida in order of abundance are: ilmenite, leucoxene,
zircon, staurolite, sillimanite, epidote, rutile, tourmaline, kyanite, hornblende, garnet, topaz,
corundum, andalusite, monazite, anatase, sphene, xenotime, spinel (gahnite), chloritoid,
brookite, and beryl. Cassiterite was found only in certain heavy mineral concentrates. Titano-
magnetite, pyrite, and hemoilmenite were determined under the ore-microscope.

While in the Early Tertiary Florida was characterized by the deposition of limestones
on a shallow carbonate platform, in the Miocene influence of plastic material from the Appala-
chian mountains increased. Deposition of the well-known Hawthorn Group had already been
influenced by glaciations of the Antarctic.
In Early Pliocene time a transgression led to sedimentation of shelly and carbonaceous
sands in northeastern Florida. Initiated by a glacial episode 3.1 to 2.9 Ma B. P., braided rivers
deposited huge amounts of coarse sand on the Atlantic and Gulf coastal plains. During a short
transgression between 2.8 and 2.6 Ma B. P. these fluvial sediments of the Citronelle-
Cypresshead Formation were partly reworked in Florida and the Central Ridges of the Penin-
sular of Florida were formed.

Information about the Late Pliocene/Quaternary history of Florida is very limited and a
model had to be developed to allow correlation of the various known fossil shoreline
complexes (Wicomico = + 30.5 m, Penholoway = + 21.3 m, Talbot = + 12.8 m, Pamlico =
+ 7.6 m, Princess Anne = + 4.0 m, Silver Bluff= + 1.4 m) with dated global events:
The Pamlico shoreline complex was definitely formed during the last interglacial which
had its climatic optimum 125 ka B. P. Maximum mean sea level of this interglacial was not
higher than + 6 m. Assuming a constant rate of uplift (1.28 cm/1,000 yrs.) and reasonable for-
mer mean sea level elevations, ages of all the other shoreline complexes can be calculated.
Comparison of these hypothetical shoreline ages with well-established global climatic
variations revealed the following stratigraphic history, which is in excellent agreement with
biostratigraphic results from other parts of the Atlantic coastal plain and the Gulf of Mexico.
Following a series of glacial episodes between 2.4 and 2.0 Ma B. P., the Wicomico
transgression can be dated 1.9 -+ 0.1 Ma B. P. Another series of climatic deteriorations
between 1.8 and 1.5 Ma B. P. separates it from the Penholoway transgression 1.3 + 0.1 Ma
B. P. Sediments of the Talbot shoreline complex (ca. 550 ka B. P.) are not defined in the area
of investigation. The age of the Pamlico transgression has already been mentioned. It was
followed within a very few thousand years by the Princess Anne transgression. The Silver Bluff
complex was formed during the Holocene climatic optimum about 6,000 years ago.








With original reserves of more than 1.3 billion metric tonnes of ore sand or nearly 52
million metric tones (Mt.) of available heavy minerals, Trail Ridge is one of the largest heavy
mineral placer deposits in the world. The southern areas of this pronounced feature of 230 km
length have been mined since 1946. Underlying the mineralized eolian sands in the southemn-
most part are peats of a former cypress swamp which was buried by migrating dunes. These
dunes received their material from beach sands of the former Atlantic coast to the east. Waves
at that time (1.9 + 0.1 Ma B. P.), on the other hand, were mostly reworking relatively coarse
fluvial sands of the Citronelle-Cypresshead Formation. Mineralogical and granulometric char-
acteristics of this partly eroded Formation are still preserved in the dune sands of Trail Ridge.
To the west of the southern part of Trail Ridge, the former Gulf of Mexico acted as a barrier to
the migrating dunes. Farther to the north, Trail Ridge did not exist as a single ridge from the
beginning, but large islands were separated by tidal inlets, deltas and even marine straits. Pro-
longed dune migration led to the formation of the present-day ridge which was partly eroded
and partly covered by barren eolian sands during later Pleistocene climatic oscillations.

The Folkston deposit in southeastern Georgia was mined between 1965 and 1974.
Nearly 29 Mt. of ore sand and 0.6 Mt. of heavy mineral concentrates were recovered from
mostly eolian players of the Penholoway shoreline complex. Only small, hardly economic ex-
tensions of the main deposit remained unmined.

The very small Boulogne deposit contained original reserves of 26 Mt. of ore sand or
0.9 Mt. of available heavy minerals. Due to very low grades in the southern part only the
northern area was mined between 1974 and 1979 yielding 0.25 Mt. of heavy mineral concen-
trates. Sedimentologic analyses revealed the following stratigraphy in the area of mineraliza-
tion: Overlying Miocene, Early Pliocene and various Late Pliocene sediments are epidote-rich
coastal dune sands of Early Penholoway age. With transgressing seas they partly remained as
obstacles on the shallow sea floor, so that heavy minerals were deposited in the vicinity of
these nearshore bars. Sedimentologic parameters are distinctive but cannot be confused with
those of beach-storm or eolian players.

The Green Cove Springs deposit has been mined since 1972. Original reserves of the
entire district may have been around 15 Mt. of available heavy minerals. Granulometric analy-
ses of the main ore body revealed exactly the same stratigraphy as in the northern Boulogne
deposit of the same age. While heavy minerals in this main ore body were also deposited in the
nearshore zone in front of drowned coastal dune ridges, the western ore body seems to be of
eolian origin. Differences between both ore bodies are pronounced.

West of the City of Jacksonville only small parts of a huge eolian placer deposit were
mined between 1942 and 1964. Comparable in size to the Recent Amelia Island, this former
"Jacksonville Island" was formed during the Pamlico transgression. Original reserves may be
calculated as 242 Mt. of ore sand containing 13.3 Mt. of available heavy minerals.

North and northeast of the small town of Yulee, four well-defined ridges contain an
estimated 143 Mt. of ore sand with only 4.5 Mt. of available heavy minerals. In this area
beach-storm players are overlain by low-grade eolian sands which contain the bulk of the heavy
minerals. The western ridges were formed during the Pamlico transgression whereas the east-
emnmost ridge must be correlated with the Princess Anne shoreline complex. Due to the low
grades of the entire deposit and competitive land use, the Yulee heavy mineral players will
never be mined.








Evergreen Hill, west of the Yulee ridges, was sampled for scientific reasons only; it
does not constitute a heavy mineral deposit.
At the end of the 1950s it was planned to mine a small eolian placer deposit of only 0.9
Mt. of available heavy minerals on Amelia Island. By 1970, however, it was decided to develop
the area of mineralization into a luxury resort, which became known under the name Amelia
Island Plantation.

Little Talbot Island, another barrier island of the so-called Sea Island chain, is a pro-
tected Florida State Park. Relatively high-grade eolian and beach-storm players make up theo-
retical reserves of 2.3 Mt. of available heavy minerals. Epidote and hornblende dominate the
heavy mineral suite; the percentage of the heavier and economic heavy minerals, however, is
rather small.

High-grade beach-storm players and adjacent eolian players of the Recent Atlantic
coast near Ponte Vedra Beach were the first to be mined in northeastern F~lorida, from 1916 to
1929. Mining of mineralized sands was by hand and recovery of heavy minerals rather poor.
The change of the heavy mineral composition with increasing total heavy mineral content is
well documented along Recent coastlines.

Chances of the discovery of economic heavy mineral placer deposits on the shelf off
northeastern Florida are rather slim. Reasons are manifold; further exploration should be
undertaken closer to the coast.

The heavy mineral industry of northeastern Florida has always been strongly influenced
by economic needs. Within the last 80 years mining has shifted from coastal to less populated
central areas of Florida. Recovery of heavy minerals from low-grade deposits was made poss-
ible by discoveries by Florida-based industries. While exploration headquarters are still located
in Florida, exploration has shifted into other states. In the area of investigation, however, a few
economic heavy mineral deposits may still remain undiscovered.










Florida, the southernmost state of the USA, is known to the public for only one of its
resources. This, of course, is the sand, which together with the sunshine makes Florida so
attractive to tourists not only from America and, therefore, makes up the main revenue of the
state.

For geologists, however, other natural resources are of much more interest. Phos-
phorite, for example, can be found in such a thickness and distribution, that it makes Florida to
the largest phosphate producing nation in the world. One should not forget another resource,
i. e. water, which is of even greater importance to the local population. Also of great economic
importance are building materials, i. e. sand, gravel, chalk, and limestone of every classification
which are mined above all along the central axis of the Florida peninsula.

Easily neglected is another resource group, which has a long mining history in Florida:
Starting in 1916 heavy minerals (h. m.) were mined in northeastern Florida along the beaches
of the Atlantic coast (see chapter on Ponte Vedra Beach) and products made up from these
minerals used during World War I. While the coastal reserves were depleted very soon and
similar deposits nowadays cannot be mined due to the almighty tourism industry (see chapters
on Amelia and Little Talbot Islands), exploration and, therefore, also mining has shifted into
the less densely populated interior of Florida (see fig. 1).
Since the beginning of the `80s the golden times of h. m. mining in the southeastern US
have gone and exploration has shifted into other areas. But still Florida remains one of the
more important h. m. producers in the world, as shall be shown in the following table:


Ilmenite Rutile Zircon Monazite
Australia 48 % 52 % 55 % 29 %
Malaysia 13 % -- P 12 %
USA 13 % 5 % 10 % 1 %
of which Florida 95 % 100 % 90 % 100 %
CIS 11 % 2 % 10 % --
South Africa -- 13 % 16 % --
Sierra Leone -- 25 % P --
Brazil P P P 8 %
Sri Lanka P P P --
China P -- P 39 %
India -- P P 8 %

(1989) (1989) (1989) (1986)

Tab. 1: Relative share of the most important nations in the production of some h. m. after vari-
ous authors
P = important producer, -- = no or minor producer
Ilmenite and rutile, recalculated after Lynd (1990 b)
Zircon, recalculated after Garnar (1990)
Monazite, recalculated after O'Driscoll (1988)


Introduction








In 1987, a general inquiry of my major professor in Germany, Prof. Dr. D. Henningsen,
of the University of Hannover was answered kindly by Dr. W. F. Tanner, Regents Professor at
the Florida State University in Tallahassee, who was looking for a student to assess informa-
tion explaining Trail Ridge (and its h. m. deposits) as a beach ridge. Beach ridges in northeast-
ern Florida, however, normally do not reach elevations and widths of more than one meter and
lengths of more than one kilometer. The Trail Ridge feature, on the other hand, is more than
25 m high, several kilometers wide, and more than 200 km long.
After a short study it got clear that this ridge had to be seen in close context with the
other, smaller h. m. deposits in northeastern Florida. Astonishingly enough, however, hardly
any literature about these deposits was available, so that a completely new and above all inde-
pendent report became necessary.

The collection of new data of many deposits was eased considerably by the free admis-
sion to the core library of the Florida Geological Survey (F.G.S.) in Tallahassee. While the
branch of the U.S. Geological Survey in Florida is working on hydrogeological problems only,
the F.G.S. is in charge of gathering and evaluating all available information on the geology of
Florida. It is so strongly understaffed, however, that e. g. a stratigraphic correlation of Plio-
Pleistocene sediments, which was decisive for understanding the depositional history of the
various h. m. deposits, was not available in the beginning and had to be worked out for the first
time.

In total contrast to this situation the mining companies in Florida have collected a huge
set of data for having been engaged in exploration programs for several decades. These data,
however, are not available to the public and are even seldomly used by the exploration geolo-
gists for doing work on a scientific level. While only short glimpses into these data sets were
possible when working together with E. I. Du Pont de Nemours & Co., Inc. (Du Pont) and
Associated Minerals (USA), Inc. (AMU), in 1992 renamed to Renison Goldfields Consolidated
(RGC) (USA) Mineral Sands Inc., most of the files of the former Humphreys Mining Company
(HMC) were at the author's disposal. These files, however, only made up a fraction of the for-
mer archives of HMC which consisted of analyses and extensive reports on most h. m. deposits
not only in the southeastern USA.

Economic considerations have affected the mining of h. m. in northeastern Florida for
nearly 80 years and have also influenced this work: During a worldwide price high for h. m. in
1989/90, support by exploration geologists of Du Pont and above all RGC was limited and
missing information had to be collected during discussions with other employees of these min-
mng companies.

While the original Ph. D. dissertation (in German) included
*a complete description of all analytical techniques used,
* the Cenozoic stratigraphy of northeastern Florida, and
* the theories of placer formation in various environments,
this report had to be restricted to the economic information now available on the vari-
ous placer deposits of northeastern Florida. To allow readers to see these economic data in a
wider context, however, a much more general abstract, taken from the original thesis, was
given in the beginning.







TO OBTAIN
UNITED STATES UNITS

inches
cubic yards
pounds
miles (statute)
yards
feet
inches
inches
square feet
square yards
acres
tons (short, 2000 lbs.)
tons (short)/cubic yards


DIVIDE


centimeters (cm)
cubic meters (m3)
kilograms (kg)
kilometers (km)
meters (m)
meters (m)
micrometers (pm)
millimeters (mm)
square meters (m2)
square meters (m2)
square meters (m2)
tones (t)
tonnes/cubic meter (t/m3)


2.54
0.764551
0.4535924
1.609341
0.914398
0.30479947
0.00000254
0.00254
0.092903
0.836124
4046.84016
0.907185
1.18655917


Tab. 2: United States system of measurement conversion factors








Economic geology of the heavy mineral placer deposits in
northeastern Florida

Trail Ridge

Trail Ridge is the name of a geomorphologic ridge extending from Blue Pond Lakes in
Clay Co., Florida for about 209 km to north of Jesup, Wayne Co., Georgia. Its elevation
declines steadily from 77.7 m above mean sea-level (msl) southeast of Kingsley Lakes to 60.4
m above ms1 near Highland to 51 m above ms1 east of Macclenny, where it is breached by the
St. Marys River. Farther north it reaches 46 m above ms1 west of Folkston and 42 m above ms1
east of Hoboken, Georgia. Not clearly delineated at its northern end it, nevertheless, can be
followed via Screven to northwest of Jesup, where it finally reaches an elevation of 47 m above
msl.

While before and during World War II Trail Ridge was only of interest to geomor-
phologists, only months later it became known as one of the biggest h. m. deposits in the USA.
The history of its discovery is known in detail and was described by Mining World (1948, 1955
a, b, c), Spencer (1948), Thoenen & Spencer (1948), Thoenen & Warne (1949), Thoenen
(1950), Lenhart (1951), Carpenter et al. (1953), Roberts (1955), Calver (1957), Grogan et al.
(1964), Giese et al. (1964), Peterson (1966), Garnar (1971, 1980, 1983), Pirkle & Yoho
(1970), Pirkle (1972), Pirkle et al. (1974, 1989), and Pirkle & Pirkle (1984). More recent
information can be found in Industrial Minerals (1990) and Pirkle et al.(1991).

The origin of Trail Ridge and its h. m. deposits had been discussed for decades, when
starting in 1985 (Rich b, Force & Garnar) all available and above all new data where discussed
on a scientific basis. More recent publications (Force & Rich, 1989; Force, 1991) only used the
result of this discussion explaining Trail Ridge as an eolian feature.
Granulometric and h. m. analyses by Elsner (1992 a) (see figs. 2 7) validated this
theory and even brought forth more details, so now it can be stated that:
* the northern parts of Trail Ridge started as barrier islands, merging together with falling
sea-level by migrating coastal dunes.
* the whole southern part of Trail Ridge was formed as an inland dune with winds blowing
from the Atlantic coast in the northeast to the Gulf of Mexico in the southwest.
*overlying coarse sands of the late Pliocene Citronelle-Cypresshead Fm. (3.0 Ma B. P.),
marine sands of the late Pliocene Nashua Fm. (2.8 2.6 Ma B. P.), and peat of a local
cypress swamp (2.4 2.0 Ma B. P.), the eolian sands in the south can be correlated with a
world-wide eustatic sea-level high (1.9 + 0.1 Ma B. P. = late Pliocene).
* h. m. now found in Trail Ridge were originally winnowed from sediments of the younger
parts of the Citronelle-Cypresshead Fm. which are now completely eroded.

Mining at the southern end of Trail Ridge by Humphreys Gold Corporation (HGC) for
E. I. Du Pont de Nemours & Co., Inc. (Du Pont) started in April 1949 (Trail Ridge plant) with
the separation of ilmenite and residue (a mixture of rutile, ilmenite and leucoxene). Zircon was
sold starting in 1950 (Garnar, 1983), and staurolite in June 1952 (Evans, 1955, Fulton, 1975,
1983). About 16 km north a second plant (Highland) was opened in April 1955, and in January
1958 the whole operation was taken over by Du Pont itself(see fig. 8). In mid 1993 Du Pont
commenced operations at Maxville, partially closing down its Highland facilities (Industrial
Minerals, 1993)








In place of all other heavy mineral placer deposits currently being mined or already
mined out in northeastern Florida, mining and concentration of h. m. from the Trail Ridge
deposit shall be explained in more detail.
Very detailed technical descriptions of the mining/separation processes (most of them
with photos and flow-diagrams) have been given by Lenhart (1951), Engineering and Mining
Journal (1952), Carpenter et al. (1953), Evans (1955), Roberts (1955), Mining World (1955
c), Calver (1957), Giese et al. (1964), Grogan et al. (1964), Peterson (1966), Mertie (1975),
and Thompson & Whittle (1990). More recent information can be found in Garnar (1971), and
Stouffer (1988). As a standard paper on h. m. separation processes, Garnar (1973) can be
cited, who also prepared the flow-diagram (fig. 9) of the Du Pont h. m. separation process at
Trail Ridge.

About one or two years before the start of actual mining all trees are cut and scrub is
cleared to give way for bulldozers removing the upper 15 cm of top soil for later reclamation.
Mining of the ore sand from depths of more than 20 m is by a cutterhead suction dredge float-
ing in a shifting pond. Every hour more than 1,000 tonnes of sand from an area of 30,000 -
40,000 m2/month are being mined. The cut-offgrade at Trail Ridge is 3 wt.-% h. m., with a
cut-off grade of 2 wt.-% h. m. in nearly all other h. m. placer deposits in Florida.
With the ground-water level only 1 2 m below surface, a sand-water-mixture is
sucked in which is pumped by pipelines to a floating wet mill. There more than 1,000 Hum-
phreys spirals are used to concentrate the h. m. by gravimetric processes only. First rougher
spirals manage a concentration of 4 wt.-% h. m. in the ore sand to 10 15 wt.-%, intermediate
cleaner spirals enrich to 40 50 wt.-%, while finally finisher spirals produce a wet mill concen-
trate with an average grade of 80 85 wt.-% h. m. Scavenger spirals are also inserted for the
separation of h. m. from middlings and tailings. A sample of the wet mill concentrate randomly
taken at the Highland plant even contained 91.29 wt.-% h. m. (Elsner, 1992 a). The average
wet mill recovery factor is 80 % h. m., with most light h. m. being returned to the end of the
dredge pond.
Before entering the dry mill process the wet mill concentrate is treated with sodium
hydroxide, which is used to remove all organic coatings which otherwise would make separ-
ation more difficult. After drying, the hot wet mill concentrate is placed in the stationary dry
mill. Here at the beginning electrically conducting minerals are separated fr-om non-conducting
ones in several steps by ionizing the minerals at 35,000 V in rougher, scavenger, and cleaner
high-tension separators. High-intensity magnets are later used to separate the magnetic miner-
als of the conducting fraction, i. e. mainly ilmenite. The non-magnetic minerals of the con-
ducting fraction are treated as outlined in fig. 9 and finally separated in a coarse staurolite and
a high-TiO2 TCSidue concentrate. From the non-conducting fraction another magnetic staurolite
concentrate (Biasill) and more important various zircon concentrates in a zircon-mill using
gravimetric processes again are being produced. The average dry mill recovery factor is much
higher than 90 % h. m.

In the early '90s at Highland only ilmenite, residue, and staurolite concentrates were
being produced, while the zircon-quartz rest was moved to the Trail Ridge plant for separation
of zircon concentrates.

In northeastern Florida in 1992 Du Pont produced ten different h. m. concentrates,
namely:
* titanium-mineral concentrates: Ilmenite, and Residue
* staurolite concentrates: Biasill, Coarse Staurolite, and Starblast
* zircon concentrates: Standard Zircon, Premium Zircon, Zircon T, Zirclean, and Zircore.







Data regarding the characteristics of those h. m. concentrates, i. e. their mineralogical,
chemical, and granulometric composition can be found in appendix II.

After mining of the h. m. enriched sand the former mining areas are leveled and planted
with fast-growing plants against wind erosion. The loosening of the soil equals the volume
reduction by extracting the h. m. and even increases the value of the land (T. E. Garnar, pers.
comm. 1990).
Sewages are cleaned in settling basins by adding lime to settle out suspended particles
and afterwards are released into local creeks..

In 1988 about 260 people were working for Du Pont in Florida (Pirkle & Reynolds,
1988) only a small increase compared to 1952 with a staff of 225 (Engineering and Mining
Journal, 1952).

As for this work detailed economic data from only one h. m. deposit of northeastern
Florida were available (Yulee deposit) none of the well-known methods for calculating the
content of ore deposits were applicable. Instead a simplified formula was used, which, how-
ever, has often yielded more than just satisfactory results (Dr. P. Simon, pers. comm. 1990).

This formula is: HM = Q x P
while: Q =Vx W, and
while: V =Ax T.

In this formula A is the area of the ore deposit in m2 and T the average ore thickness in
m. Using these two figures V, the volume of the ore deposit in m3 can be calculated. By multi-
plying with the weight factor W, here the weight of the ore sand in tonnes per m3 (t/m3), hence
follows the content of the ore deposit in tonnes. Another multiplication with the h. m. concen-
tration P in weight percentages gives the amount of all available h. m. in tones. This figure
can easily be splitted into the various economic minerals if the h. m. composition is known.
Most problematic beside the knowledge of the key factors A, T, and P, is the weight
factor W. Although figures (Baxter, 1977, p. 116) and formulas (Macdonald, 1983, p. 61) for
its calculation can be found in the literature, comparisons with data from h. m. deposits of
northeastern Florida mined out are not in line except from the Trail Ridge deposit After Lynd
& Lefond (1983, p. 1341) weight factors of h. m. deposits in the southeastern USA vary
between 1.44 and 1.60 t/m .

Especially the calculation of the content of the Trail Ridge deposit proves to be very
difficult. Nearly all literature data on its available h. m. reserves date back nearly 30 years and
were given by Meyer (1960), Giese et al.' (1964), and Peterson (1966). According to these
publications the whole Trail Ridge deposit was said to contain about 500 mill. metric tones
(Mt.) of ore sand, of which by assuming a h. m. concentration grade of 3.9 wt.-% on the aver-
age an amount of 19.4 Mt. available h. m. can be derived. In 1988 Fantel et al. supposed both
the Green Cove Springs and the Trail Ridge deposits still to contain reserves of more than
1 billion metric tones of ore sand. Carpenter & Carpenter (1991), on the other hand, stated
the original h. m. content of both the Trail Ridge and Highland sections of the Trail Ridge de-
posit to have been 42.6 Mt.

For this work a complete recalculation of the geological h. m. content of the deposit
seemed advisable. For this task the following data were at hand:







The area of the whole Trail Ridge ore deposit is not known in detail. In fig. 8 only the
eastern outline of the Highland deposit is based on drilling results (T. E. Garnar, pers. comm.,
1991). The western limit approximately equals the Clay-Bradford County border line, where
the ore thickness is close to 3.7 m (12 feet) (N. W. Stouffer, pers. comm., 1990). Technically
mining of heavy mineral rich sands with a thickness of less than 6 m is not possible (or rather
not economic) (N. W. Stouffer, pers. comm., 1990), so that the exact western limit of the Trail
Ridge ore body was never determined and Du Pont does not even possess any mining rights in
that area (T. E. Garnar, pers. comm., 1991). The extent of the Maxville ore body to the north
was taken from the sketchy map by Pirkle et al. (1977). The outline of the southern Trail Ridge
deposit was taken from topographic maps, a draft by Pirkle et al. (1970), and a sketch map by
N. W Stouffer (written comm., 1990).
These outlines cited above were kindly planimetrically measured by Dr. E. Hofmeister
of the Geological Survey of Lower Saxony at a scale of 1:24,000, resulting in 30.0 km2 for the
Trail Ridge deposit (south of Rd. 225), 21.9 km2 for the Highland deposit (between US 301
and Rd. 225), and 25.7 km2 for the Maxville deposit (north of US 301). These figures add up
to 77.6 km2 for the whole southern Trail Ridge ore body, of which 9.9 km2 COuld not or will
not be mined for rights of possession (N. W. Stouffer, written comm., 1990).

The average thickness of the ore body was given by Carpenter et al. (1953), Evans
(1955), Calver (1957), E. V. Whittle (1957, and pers. comm., 1990), Mertie (1958, 1975),
Pirkle & Yoho (1970), Pirkle et al. (1971), Lynd & Lefond (1975, 1983), and Mallard (1986)
to be 10.7 m (35 feet). The maximum ore thickness is 21.4 m (70 feet) (Garnar, 1972, 1978 b;
Force & Garnar, 1985; Fantel et al., 1986; N. W. Stouffer, pers. comm., 1990).

tm.The weight factor is known quite well after Humphreys Gold Corporation to be 1.60

The average h. m. concentration of the ore deposit is 4 wt.-% after Thoenen (1950),
Lenhart (1951), Carpenter et al. (1953), Evans (1955), Calver (1957), E. V. Whittle (1957,
and pers. comm., 1990), Meyer (1960), Pirkle & Yoho (1970), Pirkle et al. (1971), Mallard
(1986), and Force (1991). Force & Garnar (1985) cited a concentration of 3.5 wt.-%, while
Mining World (1948), Spencer (1948), and Mertie (1958, 1975) published an average value of
3.9 wt.-%. R. M. Carver (pers. comm., 1990) mentioned 2.4 to 3.5 wt.-% for the Maxville
deposit with an average grade of 3.1 wt.-%. A calculation of average data of ore sands from
cores stored at the Florida Geological Survey core library (Elsner, 1992 a, see fig. 7) gave an
average concentration of 3.93 wt.-% h. m..

Using A = 77.6 km2, T = 10.7 m, W = 1.60 t/m3 and P = 3.9 wt.-%, V can be calcu-
lated with 830.32 mill. m3 of ore sand with a weight of 1,328.51 Mt. By this the original con-
tent of the ore deposit can be calculated with 5 1.8 Mt. of available h. m. (original reserve base,
after U.S. Bureau ofMines/U.S. Geological Survey, 1980), which were made up by about 27.4
Mt. of titanium minerals, 7.8 Mt. of zircon, 8.9 Mt. of staurolite, but only 15,500 tonnes of
monazite (see tab. 3).

Based on these data it becomes clear that before the start of mining in 1949 the Trail
Ridge ore body was not only the biggest h. m. deposit of the Atlantic coastal plain (Mertie,
1958; Pirkle et al., 1984; 1989; Force & Garnar, 1985; Force & Rich, 1989), but one of the
five biggest h. m. placer deposits in the world (see tables 22 and 23).











A


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Not being mined can or could be about 2.5 Mt. of h. m. (A = 9.9 m2, ...8 m
W = 1.60 t/m P = 2 wt.-%) due to missing rights of possession, and another 0. 16 Mt. ( A =
77.6 9.9 = 67.7 km2, T = 0. 15 m, W = 1.60 t/m3, P = 1 wt.-%) from the upper 15 cm of top
soil.
Combining all these new data it can now be stated that Du Pont originally had reserves
of 49. 1 Mt. of h. m. at its disposal, of which, at a rough estimate, about 65 % have been mined
up to date.








Folkston


The Folkston ore deposit is situated about 4 km north of the St. Marys River in
Charlton Co., Georgia, but must be dealt with when describing the h. m. deposits in northeast-
ern Florida. About 8 km north of the Trail Ridge feature the Folkston deposit lies between 24
m to 30 m above msl, only 3 km west of the St. Marys Meander Plain, which reaches eleva-
tions of only 4 m to 6 m above msl. The main area of he Folkston deposit encompasses the
central part of a very weakly delineated north-south trending ridge with a width of 2 km and a
length of 11 km. The only sharp limit of this ridge is marked by Baileys Branch, a local creek
flowing into the Satilla River. Further to the west and northwest three more, very small h. m.
deposits are known (see fig. 10), which can be correlated with even smaller ridges.

The Folkston h. m. deposit was discovered in 1952 by Du Pont in the course of an ex-
tensive exploration program on h. m. At the end of the '50s Humphreys Gold Corporation was
commissioned to go into planning for the mining of this deposit, which finally took place be-
tween August 1965 to July 1974 after leaving the Jacksonville deposit. Only the main deposit
was mined, starting in the south and moving northward with an approximate rate of 43 1 tones
ore sand every hour or 6,000 m2/month (Humphreys Mining Company, 1974). Worth men-
tioning is the crossing of Georgia Highway 252, which took place within one month, leaving a
strip of 32 m (105 ft.) unmined to both sides of this road. Also for the first time in Florida h. m.
mining history reclamation took place at the end of mining, which left behind "'eye-pleasing'
green pastures enhanced by two lakes for recreation and water storage" (Mining Engineering,
1936, p. 36) and gained Humphreys Mining Company an award by the state of Georgia for
"outstanding reclamation of surface mined land" (Garnar, 1978 b).

The geology and age of the Folkston h. m. deposit has never been looked at in great
detail. By comparison with granulometric, mineralogical, and geomorphologic data from other
deposits (especially Jacksonville) it can be supposed, however, that the main deposit formed as
a part of a barrier island. Its age can be correlated with one of the maxima of the Penholoway
transgression, about 1.3 + 0. 1 Ma B.P.. The Folkston north and west extensions are presumed
to have formed as nearshore bars during the same transgression.

The composition of the h. m. suite of the Folkston placer deposit (main area) is known
from
a.) one report (Humphreys Gold Corporation, 1959),
b.) one sample of original ore sand (see fig. 1 1) placed at the author' s disposal by John
Gully, former employee of Humphreys, and
c.) one random sample taken in the field near the surface, 600 m northwest of the for-
mer mining site south of Baileys Branch









a) pilot study b) Folkston ore sand c) sample,
HGC (1959) south of Bailevs Branch
h. m. content 3.81 I % 4.22 % 0.68 %
ilmenite 59.6 % 31 % 28 %
leucoxene in ilmenite 27 % 23 %
rutile in ilmenite 7 % 7 %
zircon 16.5 % 9 % 11 %
kynie7.9 % 2 % 2 %
sillimanite in kate5 % 13 %
andalusite in kaie+ 1 %
staurolite 11.5 % 9 % 7 %
tourmaline in staurolite 3 % 2 %
epdoe3.7 % 3 % +
gantin eioe1 % 0 %
hornblende 0.0 % + 1 %
monazite 0.8 % 1 % 1 %
xenotune mn monazite + +
toaz0.0 % 1 % 2 %
corundum 0.0 % 0 % 1 %
spiel0.0 % 0 % +
anatase 0.0 % + 1 %
sphne0.0 % + 0 %
chloritoid 0.0 % + 0 %

Tab. 4: H. m. composition of ore sands of the Folkston placer deposit (main area) (compare
fig. 14). Notice good correlation between samples a) and b) (except titanium minerals
and zircon contents). After Lynd & Lefond (1975, 1983), the titanium mineral content
of the ore sand of the main area was 56 %.
All data in wt.-%. (+ = less than 0.5 wt.%)

Similar to the Trail Ridge deposit the Folkston placer deposit was mined by a cutter-
head suction dredge with a pre-concentration of h. m. in a wet mill by Humphreys spirals. In
the stationary dry mill a mixed concentrate of titanium minerals (ilmenite, leucoxene, and ru-
tile), called titanium product, was produced. In the zircon (wet and dry) mill zircon was the
end-product, while an important by-product used to be a monazite concentrate. About its pro-
duction (see fig. 11) former chief engineer E. V. Whittle wrote in a private letter to A. E.
Humphreys in Denver in 1966: In the operation of the crossbelt the feed is introduced on an
endless belt which in turn passes under seven magnetic belts each of increasing magnetic inten-
sity and operating at right angles to the feed belt. As the feed passes under each of the seven
crossbelts, the magnetic material is lifted and moved to one side until it is removed from the
magnetic field and drops into a pocket for removal. Belt #1 is the least magnetic and, there-
fore, removes only the most magnetic material such as rust, iron fillings, etc. Each succeeding
belt is in turn more magnetic and removes a correspondingly less magnetic material from the
feed belt. Belt #2 removes primarily garnet, #3, garnet-staurolite, #4, staurolite-monazite and
#5, 6, 7 remove monazite. Some material remains on the feed belt and is returned to the zircon
mill. This material is mostly zircon and is referred to as 'tail belt product'."








This means that only three different h. m. concentrates were produced at Folkston:
- a titanium product containing ilmenite, leucoxene, and rutile, and
- a zircon concentrate, which both were sold to Du Pont, as well as
- a monazite concentrate, which was bought by the chemical company W. R. Grace & Co.

To increase the amount of rare earths (RE) in the monazite concentrate (and thereby
selling it at a higher price), xenotime was separated from "belt #2" and mixed with the mona-
zite. By this procedure it was possible to increase the rare earths oxide (REO) content from
about 56 57 % to more than 60 %, which also had its effect on the relative content of some
of the heavier rare earths (see chemical analyses in appendix II).
Xenotime as a separate product, however, was never sold at any time (E. V. Whittle,
pers. comm., 1990; Thompson & Whittle, 1990).

In 1971 (unpublished) J. Gully had a closer look at the zircon wet mill tailings (see fig.
11), finding : 64.3 wt.-% quartz,
27.2 wt.-% staurolite, garnet, and epidote,
6.4 wt.-% kyanite, and sillimanite,
2. 1 wt.-% zircon, and
traces of ilmenite, leucoxene, and rutile.
76.0 wt.-% of the h. m. fraction of 35.7 wt.-% were magnetic, consisting above all of
staurolite, as well as minor amounts of garnet, epidote, ilmenite, and leucoxene.
The non-magnetic part of 24.0 wt.-% was made up of about 80 85 %
kyanite/sillimanite (see appendix II: II-F.-Kyasill), 15 20 % zircon, and traces of rutile and
leucoxene.

In 1973 T. E. Garnar analyzed a similar sample from Folkston getting these unpub-
lished results:
ilmenite 2.4 %
leucoxene 6.9 %
rutile 0.2 %
garnet 2.0 %
epidote 14.3 %
staurolite 3 1.2 %
tourmaline 6.9 %
kyanite 9.3 %
sillimanite 21.6 %
zircon 5.2 %.

As the Folkston placer deposit, or rather its main area, was mined completely, com-
parisons between the estimated (Humphreys Gold Corporation, 1959) and the final
(Humphreys Mining Company, 1974) mining data are possible. Also a recalculation of the
original h. m. content can be made (see tab. 5).





Tab. 5: Planned and achieved production, and recalculation of original reserve base of the
Folkston placer deposit (main area) (all data in metric tones = t)


re-calculation
Elsner (1992 a)


pilot study
after HGC (1959)


mined 1965 1974
(after HMC (1974)


A (km2)
T (m)
V (mill. m3)
W (t/m')
Q (Mt.)
P (%)
HM (Mt.)


7.097
2.5
17.741
1.78
31.580
4.25
1.342


7.097
2.5
17.741 (?)
1.73 (7)
30.638 (3)
4.27
1.308


ca. 6.5
2.5
15.860 (?)
1.78 (?)
28.946472
4.25
1.230


available
ca. 800,000
ca. 121,000
ca. 13,400


available/mineable
779, 719/545,805
215,862
10,466


produced
462,001
128,863
11,415


Titanium Product (t)
Zircon (t)
Monazite (t)

mining operating time
average
mining .recovery (HM)


(60 %)
( 9%)
(1 %)


3,170 d/67,210.2 h
.21.20 h/d
94 %

3,170 d/70, 173.6 h~
22.14 h/d
823,547


82.4 %

70.0 %

3075 d/70,745.7 h
23.01 h/d
602,279
94.3 %
73.1 ?/


.92 %




85 %
85 %
80 %
70 %


wet mill operating time
average
wet mill concentrate (t)
wet mill recovery (z~ircon)
wet mill recovery (monazite)
wet mill recovery (TiO2)
wet mill recovery (unecon. HM)
wet mill recovery (total HM)


dry mill operating time
average
dry mill concentrate (t)
dry mill recovery (TiO2)
dry mill recovery (HM)


95 %


'70 %
80 %


zircon wet riill recovery (Zrp2)
zircon dry mill recovery (ZrO2)







"western extensions" "northern extensions" total

TiO2 in Ore sand 1.48 % 1.83 % 1.80 %

A (kmi 0.904 1.217 9.218
T (m) 1.6 (?) 2.0 (?) 2.3
V (miD. m ) 1.447 2.435 2.
W (t/mJ) 1.78 (?) 1.78 (?) 1 .78 (7)
Q! (M~t.) 2.576 4.334 38.5
P (%) ca. 3 (?) ca. 4 (?) ca. 4
HMl (M~t.) 0 077 0. 173ca16

Tab 6: Economic geology of the "west" and "north extensions" of the Folkston placer deposit
and assumed original reserve base of the Folkston placer district
(TiO2-COntent after Humphreys Gold Corporation, 1959, "main area": 1.84 %)

All three individual players of the Folkston placer district contained about 1.6 Mt. of
available h. m., of which most (ca. 80 %) were mined between 1965 and 1974. The Folkston
placer district, therefore, can be considered depleted by both economic and geologic aspects.







Boulogne


The Boulogne h. m. deposit was named after a small village with the same name,
located at the St. Marys River close to the Georgia State border. Following Florida State Road
121 from Boulogne to the south one reaches the northern boundary of the~ placer deposit after
2.5 km.
As near Folkston, before mining the area was covered with trees and characterized by
numerous small ponds and swamps. The deposit itself encompassed the central part of a ridge
trending nearly north-south, and reaching a width of 1.9 km and a length of more than 5.3 km.
With an average altitude of the surroundings of 23 to 27 m above msl, the highest point of the
ridge, i. e. the deposit was 32.6 m above msl.
Of utmost importance for the explanation of its origin is another ridge, 3.5 km north-
east, reaching a width of 2.8 km and a length of 5.6 km. This "Pigeon Creek Church Ridge" is
separated from the Boulogne ridge by the Pigeon Creek, draining into the St. Marys River via
Hampton Lake (see fig. 12).

Nothing has ever. been published about the discovery of the Boulogne deposit. Most
probably it was found in the wake of the exploration program for the Folkston placer district in
the '50s. (compare fig. 13). Without mining the Folkston placer deposit first, production at
Boulogne would have never been feasible. With Folkston, however, the necessary personnel
and infrastructure was at hand and in July 1974 the complete wet mill and dredge from Folk-
ston were dismounted, cleaned and rebuilt at Boulogne within only four months. On Nov. 20,
1974 mining and separation at Boulogne started, although the wet-mill concentrate had to be
hauled to Folkston by truck for further processing in the dry mill. (Garnar, 1978 b, E. V.
Whittle, pers. comm., 1990). As in all the years before a "Titanium Product" and the zircon
were sold to Du Pont while the monazite was shipped to W. R. Grace & Co. (Thompson &
Whittle, 1990) (compare fig. 14).
Starting from the north and soon crossing Florida State Road 121, mining moved to
the south, with ore grades steadily decreasing. South of a minor road further mining would not
have been feasible anymore (E. V. Whittle, pers. comm., 1990), so on Oct. 14, 1979 the
dredge and wet mill at Boulogne closed down, followed 40 days later by the dry mill in Folk-
ston.
After reclamation of the Boulogne deposit in 1980 (Garnar, 1983) it was planned to
start mining the Altama h. m. placer deposit near Brunswick, GA, which was described by
Pirkle et al. in 1989. As world market prices for h. m. were very low, however, mining this
deposit would not have been feasible anymore, so that in 1980 Humphreys Gold Corpora-
tion/Humphreys Mining Company, after more than 90 years of activity, had to go out of busi-
ness.
Continuing some of Humphreys former activities is Carpco, Inc. in Jacksonville, a con-
sultant, which once arose from Humphreys Gold Corporation itself.

It was possible to outline the complete geology of the Boulogne deposit by
re-analyzing the core "Boulogne 1", which after 25 years still is stored in the F.Gi.S. core
library (see fig 15). The findings of these analyses have been explained in detail by Elsner
(1992 a, b). There it was stated that the placer itself was formed in a nearshore bar environ-
ment at the maximum of the Penholoway transgression, some 1.3 Ma. B.P. Most probably
during the following regression barrier islands formed a little bit farther east, allowing h. m. to
be concentrated in dunal systems, leading to placer deposits like Folkston "main area" and pre-
sumably "Pigeon Creek Church Ridge".








Mining, processing, and separation of h. m. from the Boulogne deposit was exactly the
same as near Folkston (see fig. 11). Naturally production data were quite different, however,
and can be quoted after Humphreys Mining Company (1980) as follows:


wet mill feed
wet mill tailings
wet mill concentrate .
organic index before scrubbing
organic index after scrubbing
dry mill non-conductors
zircon wet mill tailings
Titanium Product
zircon concentrate
monazite concentrate


3.75 % h. m.
1.09 % h. m.
68.2 % h. m.
196


@ 1.32 % TiO2
@ 0.28 % TiO2
@ 29.9 % TiO2, 6.8 % ZrO2


43.4 % h. m. @ 2.43 % TiO2, 11.9 % ZrO2
27.1 % h. m. @ 1.35 % TiO2, 0.82 % ZrO2
71.7 % TiO2, 0.67 % ZrO2
65.8 % ZrO2, 0. 13 % TiO2, 0.58 % Al203
63.3 % T.O., 0.56 % TiO2, 2.91 % ZrO2, 7.9 % insol.


After an unpublished map at a scale of 1:4,800 (E. V. Whittle, unpublished) the area A
of the northern part of the Boulogne placer deposit, which was mined out, is known quite pre-
cisely to be 2.571300 km2. After Pirkle et al. (1971, p. 18, 1974, p. 1131, and 1977, p. 50) the
total area of the Boulogne placer deposit was about 4. 149 km2, Of which 3.259 km2 belonged
to the northern, and 0.890 km2 10 the southern part.

After Pirkle et al. (1971, 1974), Lynd & Lefond (1975, 1983), Garnar (1978 b, 1980,
1985), and US Bureau of Mines (1987), the average thickness of the ore sand in the area
mined out was varied between 5 and 25 ft. (1.5 to 7.6 m). After Thompson & Whittle (1990)
as well as E. V. Whittle (pers. comm., 1990) the mean ore thickness was 15 ft. (4.6 m). Com-
paring all these information with data from Humphreys Mining Company (1980), who summa-
rized all available production data, the following table can be presented:





Tab. 7: Original reserve base of the Boulogne placer deposit and production data of the area
mined between 1974 to 1979 (after Humphreys Mining Company, 1980)

In 1987 the original reserves of the Boulogne placer deposit were stated by the U.S.
Bureau of Mines to have been some 20 mill. short tons (= 1 8. 14 Mt.) of ore sand. This is only
about 70 % of the recalculated figure of 26.325 Mt. given above.


northern


southern


total


mined
1974 1979


part


A (km )
T (m)
V (mill. m')
W (t/m')
Q (Mt.)
P (%)
HM (Mt.)

Titanium Product (t)
Zircon (t)
Monazite (t)


3.259
4.6
14.991
1.41
21.138
3.75
0.793

490,000
100,000
4,000


0.890
4.0
3.560

5.020
2.0
0.100

60,000
13,000
500


4.149
4.5
18.671

26.325
3.4
0.895

555,000
115,000
4,500


2.517300
4.6
11.572
1,41
16.3 16745
3.75
0.612

193,137
50,046
2,834


mining operating time
average
mining recovery (HM)

wet mill operating time
average
wet mill concentrate (t) .
wet mill recovery (TiO2)
wet mill recovery (HM)

dry mill operating time
average
dry mill concentrate (ty
dry mill -recovery (TiO2) -
dry mill recovery (HM)


1,707 d/35,579.4 h
.20.84 h/d
95.2 %

:1,701 d/35,579.4 h
20.84 h/d
545,623
79.5 %
.63.9 %j

1,717 d/37,965.8 h
22. 1 1h/d
246,017
97.1 %
72.8 %








Green Cove Springs


The Green Cove Springs h. m. placer deposit (Clay Co., FL.) was named after a small
village with the same name, located at the western shore of the broad St. Johns River. The
main ore body stretches from a few kilometers southeast of the village for about 19 km to the
south near Bostwick. The average width of this deposit is 1.4 km (maximum: 2.4 km). It forms
the eastern and central part of an only weakly delineated ridge, which is reaching an elevation
of about 40 m above msl. west of the deposit.
Approximately 2.4 km farther west lies the small ore body, reaching a width of only a
few hundred meters and a length of some 7 km.
This small ore body, on the other hand, is separated by a zone some 100 200 m wide
and without any h. m. enrichments from the western ore body, which also is about 7 km long
and about 1.3 km wide. In sharp contrast to the main ore body this western ore body encom-
passes an obvious ridge, which overtops the surrounding swamps by ca. 8 m (maximum eleva-
tion: 39.3 m above msl.). Similar to Boulogne the area is tree-covered and dotted with numer-
ous shallow swamps. Forestry is by the Union Camp Corporation (see fig. 16).

The main ore body of the Green Cove Springs placer deposit was found in 1966 by an
exploration geologist, who was working for Union Camp Corporation and in charge of investi-
gating all company-owned forest areas in the southeastern US. Apart from finding the Green
Cove Springs placer deposit he was lucky enough to discover the Altama h. m. placer deposit
near Brunswick, Georgia (Pirkle et al., 1989) as well, which has already been mentioned one
chapter before (E. V. Whittle, pers. comm., 1990).
For the mining of the Green Cove Springs deposit a company named Titanium Enter-
prises was founded by both Union Camp Corporation as the land-owner (50 %) and American
Cynamid as the mineral purchaser (50 %) (Pirkle et al., 1971, 1974, Garnar, 1972, 1978 a, b,
1980, Lynd & Lefond, 1975, 1983, Industrial Minerals, 1978, Harvey & Brown, 1986, Pirkle
& Reynolds, 1988).
Mining started in 1972 from the north proceeding southward. Of these, first years not
much is known, besides hat titanium minerals, zircon, and monazite were separated. Thoughts
about also producing garnet (I.-G.C.S.-garnet, see appendix H) and staurolite (I.-G.C.S.-
staurolite) concentrates in the mid of the '70s did not advance (C. Webb, pers. comm., 1991).
According to Industrial Minerals (1979 b) the average mining rate was about 1,000 tonnes/
hour; after in 1976 production of monazite was increased. In 1971 Pirkle et al. assessed that
there were enough mineral reserves for a mining period of 25 to 28 years.

On July 1, 1978 (Industrial Minerals, 1978 a), however, Titanium Minerals stopped
production, mainly for the dramatic decrease of zircon prices on the world market (Industrial
Minerals, 1980 a). To keep losses at a minimum tailings were processed for staurolite, zircon,
and monazite during the following sale negotiations (Industrial Minerals, 1978, 1979 a, b,
Garnar, 1980 a, Harvey & Brown, 1986)t
Humphreys Mining Corporation was one of the first companies being informed about
the planned sale of the Green Cove Springs deposit. Because of having economic problems
itself, it was not able, however, to shift production from Folkston to Green Cove Springs
(E. V. Whittle, pers. comm., 1990). In late April 1980, after working out a feasibility study, the
whole operations and mining permits of the Green Cove Springs deposit were bought by
Associated Minerals Consolidated Ltd. (AMC), a subsidiary of Consolidated Gold Fields Aus-
tralia (now: Renison Goldfields Consolidated Ltd. = RGC) for 11.7 mill. US-$. Investments of
another 6 mill. US.-$ were planned for the coming years, as reserves should be high enough to
allow a yearly production of 25,000 tones of rutile, 25,000 tones of zircon, 50,000 tones of







ilmenite, and minor amounts of leucoxene, monazite, and staurolite for the next 16 years
(Industrial Minerals, 1980 b).
After the taking over of the deposit by AMC and the founding of the subsidiary Asso-
ciated Minerals (USA) Inc. (AMU) staurolite was being produced for the first time from Green
Cove Springs. In 1985, however, production of this mineral already ceased (Garnar, 1987). By
applying Australian knowledge and being the only US-producer of a rutile concentrate
(capacity: 32,000 tonnes/yr., after Lynd, 1987; production: 27,000 tonnes/yr., after Lynd,
1990) first profits could be realized as early as 1983 (Harvey & Brown, 1986).
In the progress of an exploration campaign near the main ore body in the early '80s as
another success the western and small ore bodies were discovered. After Harvey & Brown
(1986) by finding these deposits the reserves of AMU (in 1992 renamed to RGC (USA) Min-
eral Sands Inc.) were doubled.

The geologic history of the Green Cove Springs deposit is very similar to that of the
Folkston and Boulogne ore bodies and has been described in detail by Elsner (1992 b). Ac-
cording to his evaluation which is based on the results of h. m. and grain size analyses of sev-
eral cores drilled in the h. m. deposits of northeastern Florida and information by the mining
companies, the main ore body was formed in a nearshore bar environment during the Penholo-
way transgression, some 1.3 + 0.1 Ma. ago. While nothing certain is known about the origin of
the small ore body, the western ore body must have been formed as a coastal dune containing a
totally different h. m. suite with less economic minerals than in the main deposit (see figs. 17
and 18 and tab. 8).









Boulogne ~Green CoveSpns
Boulogne 1 Union Camp 3 Union Camp 1 Union Camp 2 wesern ore body
(Wr 10482) -- (W 10481) (W 12112)
Surface elevation 30.8 m 36.0 m 34.1 m 25.9 m --
Ore thickness 7 m 6 m 5 m 3 m 10 m
Average grade
Elsner (1992 a) 2.71 % --- 8.36 % 7.92 % 3.25 %
Pirkle et al. (1971, 1991) 3.12 % 3.67 % 4.83 % 3.67 % ---
Economic minerals
Ilmenite 35.2 % --- 33.9 % 33.6 % 26 %
Leucoxene 19.8 % --- 20.3 % 19.1 % 17 %
Rutile 6.8 % --- 8.1 % 9.4 % 7 %
Zircon 13.0 % --- 16.9 % 13.4 % 7 %
Monazite/Xenotime 0.5 % --- 1.0 % 0.3 % 0 %
Sum 75.3 % - 80.2 % 75.8 % 57 %
Non-economic minerals
Garnet 0.4 % -- 0.7 % 0.0 % 2 %
Epiote2.4 % -0.2 % <0.1 % 13 %
Hornblende 0.6 % -- 0.8 % 0.3 % 2 %
Sillimanite 6.5 % -4.5 % 5.9 % 4 %
Andalusite 0.3 % -0.3 % 0.2 % 1 %
Kyait 1.6 % -1.2 % 1.1 % +
Staurolite 8.9 % -8.5 % 12. I% 15 %
Tourmaline 1.9 % -2.0 % 3.4 % 4 %
Spiel0.1% -- <0.1 % 0.0 % +
Corundum 0.6 % -0.2 % 0.3 % +
Toa 1.2 % -- 0.6 % 0.8 % 1%
Anatase 0.1 % -0.5 % 0.0 % 0 %
Brookite 0.0 % -<0.1 % 0.0 % 0 %
Sphne0.1 % -0.2 % 0.1 % 0 %
Chloritoid <0.1 % -- 0.0 % 0.0 % 0 %
Sum 21.7 % -19.8 % 24.2 % 43 %
Total 100.0 % 100.0 % 100.0 %/ 100 %~


Tab. 8: Average h. m. grade and composition of the Boulogne and Green Cove Springs placer
deposits (after Elsner 1992 b)

A comparison of available data on the average h. m. composition of the Green Cove
Springs main ore body is given below (see also fig. 19).
































Tab. 9: Average h. m. composition of the Green Cove Springs main ore body (all data in wt.-
%).

By mining its deposit with a bucketwheel suction dredge and the increased use of
shaking tables for the separation of the various h. m. AMU (RGC) differs from the other for-
mer and current h. m. producers in northeastern Florida. Publications showing flow-diagrams
of the Green Cove Springs plant are not known and, consequently, could also not be made
available by AMU.
Of utter importance to AMU (RGC), which currently employs about 125 people in
Florida (J. Elder, pers. comm., 1990) is an ecologically based reclamation of its mining site.

Well known are details on the h. m. concentrates produced by AMU (RGC). After
ceasing further production of staurolite in 1985, now ilmenite, leucoxene, rutile, zircon, and
monazite concentrates are being sold.
Production of ilmenite (min. 63 % TiO2) WAS 63,000 tonnes/yr. in 1986, and that of
leucoxene (65 % TiO2) 12,000 tonnes/yr. (Clarke, 1986). Further on with a capacity of 35,000
tonnes/yr. 25,000 tonnes/yr. of zircon (min. 66.5 % ZrO2) WCTC pfOduced in 1982 (Coppe,
1983), rising with an increased capacity to 35,000 tonnes/yr. in 1986 (Harvey & Brown). Pro-
duction figures of rutile were already given (27,000 tonnes/yr.), those of monazite (min. 57 %
REO, max 7 % ThO2) are said to have been 700 tonnes/yr. in 1984 (Griffiths), and the capacity
in 1988 (O'Driscoll) to have been 700 800 tonnes/yr.
Taking into account a ratio of monazite to xenotime in parts of the main ore body of
three to one (after Elsner, 1992 a), after the planned increase of the wet mill capacity to 1,800
tonnes/h about 150 300 tonnes/yr. of xenotime could be produced.


ilmenite
leucoxene
rutile
zircon
kyanite
sillimanite
staurolite
spinel
corundum
tourmaline
monazite/xenotime
garnet
epidote
hornblende
topaz
anatase
andalusite
sphene


Pirkle et al. (1991)
47.0 %
6.4 %
4.6 %
15.1 %
6.7 %
in kyanite
9.4 %
0. 1 %
0.3 %
6.2 %
0.7 %
0.5 %
3.1 %
0. 1%


Elsner (1992 a)
33.8 %
19.7 %
8.8 %
15.1 %
1.1 %
5.2 %
10.3 %
< 0. 1 %
0.3 %
2.7 %
0.7 %
0.3 %
0.1 %
0.5 %
0.7 %
0.4 %
0.2 %
0.1 %








Monazite is being sold to Rhone Poulenc, France. Rutile is send to a TiO2-pigment
plant of Kemira Oy Inc. in Savannah, GA, while ilmenite is bought by Du Pont for its TiO2-
pigment plants in Tennessee and Delaware. Leucoxene is being used by Kerr Mc Gee in
Mobile, AL to produce synthetic rutile. Zircon is crushed in South Carolina and New York to
zircon flour (see Garnar, 1980), which is being used above all in the ceramics and refractory
industries.

The volume of the deposit is difficult to calculate, especially the tonnages of available
h. m. The area of the various deposits is well known due to a map kindly supplied by AMU
(RGC) in a scale of 1:24,000 and can be given with 23.218 km2 (main Ore body), 6.022 km2
(western ore body), and 1.811 km2 (Small ore body) respectively.
The average thickness of the h. m. enriched zone in the main ore body was stated by
Pirkle et al. (1971, 1974), Lynd & Lefond (1975, 1983), Garnar (1978 b, 1980), Wynn et al.
(1985), Fantel et al. (1986), and U.S. Bureau of Mines (1987) to be 6 m (20 ft.), and after
Pirkle (1972) to be a little bit more than 4.5 m (15 ft.). In the cores ,,Union Camp 1" it was 5
m, in ,,Union Camp 2" 3 m, and in ,,Union Camp 3" 6 m (see figs. 17 and 18). An average
thickness of 5 m, therefore was assumed by Elsner (1992 a). The depth of actual mining differs
between 4.6 and 10 m (S. K. Gilman, pers. comm., 1991), while latter value also is the average
thickness of the western ore body.
The volume factor W is not known, but at least in the main ore body it should be simi-
lar to the Boulogne placer deposit, i. e. about 1.41 t/m As the western ore body is an eolian
placer a different factor of e.g. 1.60 t/m3 (see Jacksonville deposit) must be used for any calcu-
lation.
The average h. m. content of the main ore body is in dispute, as can be shown by tab.
10.

Pirkle et al. (1991) Elsner (1992 a)
depth h.m.-concentration depth b. m.-concentration
Union Camp 1 Union Camp 1
0.0 0.9 m 1.12 wt.-% 0.5 m 1.74 wt.-%
0.9 1.5 m 1.17 wt.-% 1.5 m 1.78 wt.-%
1.5 3.0 m 3.49 wt.-%/ 2.5 m 6.86 wt.-%
3.0 4.7 m 9.39 wt.-% 3.5 m 26.15 wt.-%
4.5 m 5.28 wt.-%
4.7 5.3 m 1.63 wt.-% 5.5 m 1.10 wt.-%
ore deposit (avg.): 4 83 wjt.o/-% -~ : ore deposit (avg.): 8.36 wt.-%
Union Camp 2 Union Camp 2
0.0 0.3 m 1.54 wt.-% 0.5 m 2.56 wt.-%
0.3 1.5 m 2.18 wt.-% 1.5 m 7.85 wt.-%
1.5 3.0 m 5.29 wt.-% 2.5 m 13.36 wt.-%
3.0 4.6 m 1.28 wt.-% 3.5 m 0.31 wt.-%
:ore deposit (avg.): 3.67 wIt.-% ore deposit (avg.): 7.92 wt.-%
Union Camp 3 missing in core library of FGS
0.0 1.5 m 1.30 wt.-%
1.5 3.0 m 5.16 wt.-%
3.0 4.6 m 4.84 wt.-%
4.6 6.1 m 3.36 wt.-%
6.1 7.6 m 1.53 wt.-%
ore deposit (avg.). 3.67 wt.-%/







Tab. 10: H. m. concentration of sands in cores Union Camp 1, Union Camp 2, and Union
Camp 3 (Green Cove Springs main ore body) after Pirkle et al. (1991) and Elsner
(1992 a)

Although laminar samples should not be used for economic evaluations, differences in
tab. 10 between counts of Elsner and Pirkle are so strong, that a simple explanation, like inci-
dentally (always) h. m.-enriched laminae were sampled by Elsner, is not maintainable.
Comparisons with literature data are of any help neither. The average TiO2-COntent of
1.3 % of the ore sand of the Green Cove Springs placer deposit given by the U.S. Bureau of
Mines (1987) can at least be doubted (see Wynn et al., 1985) (Boulogne: 3.75 wt.-% h. m. @
1.32 % TiO2 in Ore sand; Folkston: 4.25 wt.-% h. m. @ 1.63 % TiO2 in Ore sand). According
to Wynn et al. (1985) the Green Cove Springs deposit is volumetrically smaller than the Trail
Ridge deposit but richer in h. m. (Trail Ridge: 3.9 4.0 wt.-%). The maximum ilmenite content
is said to be 10 wt.-%, corresponding to a h. m. content of about 20 30 wt.-%.

For the following calculation an average h. m. concentration of 7 wt.-% for the main
ore body shall be assumed, while the h. m. concentration of the western ore body is known to
be 3.25 wt.-% (S. K. Gilman, pers. comm., 1990).

main ore body western ore body small ore body total
A (km3 23.218 6.022 1.891 31.131
T (m) 5.0 10.0 4.5 5.9
V (mill. m') 116.090 60.220 8.509 I84.8 I9
W (t/m3) 1.41 1.60 1.60 (?) 1.46 (?)
Q (Mt.) 163.687 96.352 13.615 273.654
P (wt.-%)C 7.0 3.25 3.25 (?) 6.05
HM (ML) 11.458 3.131 0.442 15.031

Tab 11: Economic geology of the Green Cove Springs placer deposit

The reliability of the h. m. reserves of the Green Cove Springs placer deposit calculated
above is hard to judge. Only some economic data are known very well, while others are not
known at all.
After T. E.Garnar (pers. comm., 1990) the remaining reserves at the end of the '80s
were said to be about 8 Mt. quoting an unknown Australian source. Roughly assuming that at
that time about one third of the main ore body and half of the western ore body had been
mined, this figure is in good agreement.







Jacksonville


The city of Jacksonville is situated in the centre of the northeastern Florida h. m. placer
district. Lying 6 km east of the city, now covered and surrounded by sprawling suburban
houses, another large placer deposit can be found, stretching north-south for about 17 km.
Several important highways cut through this deposit.
Before the start of mining at the beginning of the '40s, the area consisted of an ar-
rangement of sand hills side by side out of the surrounding wide marsh areas. Oak trees, pines
and palmettos thrived in the middle of a dense brushwood. The basis of the area's surface lay
relatively constant at 9.3 + 0.2 m a.s.1. (Wood, 1944). But already at that time the suburban
settlement Southside Estates was developed, below which particularly high-grade h. m. en-
richments could be drilled (but not mined).

.The northern part of the Jacksonville deposit of (see fig. 20) was discovered by the
Titanium Alloy Manufacturing Company (TAMCO), a subsidiary of the National Lead
Company (now National Lead Industries Inc.) in the course of the exploration within the scope
of the mining of the Mineral City deposit (see below) (J. Gully, pers. comm., 1991, compare
with Gillson, 1959).
In December 1942 the Rutile Mining Company of Florida (RMCoF) was founded by
TAMCO to extract the titanium minerals (Calver, 1957; Overstreet, 1967). In August 1943
mining began, but after a short time of production, however, problems appeared. The RMCoF
used a bucket wheel dredge for mining the ore sand. For h. m. concentration selectively eight
shaking tables (recovery factor: 85 92 % h. m.) or six flotation cells (recovery factor: max. 80
% h. m.) were used. The resulting h. m. concentrate then was dried in a coal-fired oven,
whereby, however, only a humidity reduction from I6 % to 6 % could be achieved.

In the dry mill the non-conducting zircon and the aluminum-silicates were separated by
electrostatic processes and then stockpiled. Electric magnets were used for the final separation
of the electrically conducting minerals ilmenite and rutile (Humphreys & Hubbard, 1945 and
unpublished notes of HGC, 1944). The rutile was used by TAMCO, whereas National Lead
was interested in the ilmenite.
Because of the described separation process only very impure rutile rich in quartz
(average 89.7 % TiO2) and ilmenite (average 58.7 % TiO2) COncentrates could be produced.
Since there was a high demand for these strategic minerals for war reasons, already at the be-
ginning of December 1943 TAMCO approached to HGC in order to increase its production
capacity by installation of some Humphreys spirals in their wet mill.

From May to December 1943 Humphreys spirals had been used in the mining of
chromite beach players in Coos Bay, OR, and HGC was very interested in a subsequent as-
signment (Humphrey & Hubbard, 1945; Thompson & Whittle, 1990). Therefore, it was agreed
upon with TAMCO to not only install some spirals but to take over the complete mining and
the extraction of h. m. out of the Jacksonville deposit. For that purpose the complete plant in
Oregon was dismantled, transported over 5,863 km to Florida (Humphreys & Hubbard, 1945)
and assembled there again (compare Gillson, 1959).







Effective from April 1, 1944 HGC took over the exclusive responsibility in Jackson-
ville, whereby the bucket wheel dredge first was replaced by a cutterhead suction dredge and a
little later the shaking tables and flotation cells by some 252 Humphreys spirals. The planned
capacity of this new plant was at 360 tonnes of ore sand per hour at 20 hours of mining per
day (Humphreys & Hubbard, 1945; Hubbard, 1948; Spencer, 1948; Thoenen & Warne, 1949;
Detweiler, 1952; Calver, 1957; Overstreet, 1967; Thompson & Whittle, 1990).
Also the separation of the h. m. in the dry mill could be arranged in a considerably
more effective way (Lenhart, 1949). Whereas the RMCoF could ship 26 railway carriages
within the eight months of their activity, HGC succeeded in extracting about the same quantity
(24 wagons with 1,023,655 tonnes of rutile) within only five months. At the same time the
quality of the products could be increased: from 58.7 % to 59.9 % TiO2 in the ilmenite and
from 89.7 % to 92.4 % TiO2 in the rutile.

Of his first year of operation it is also known that the average h. m. content of the ore
sand was 6.64 wt.-%. In the wet mill concentrate this value could be increased to 90.9 wt.-%.
In the h. m. fraction of this wet mill concentrate the rutile made up 7.4 wt.-% on the average,
and the ilmenite 44. 1 wt.-%. According to Thompson & Whittle (1990) the appropriate zircon,
or rather monazite contents were 11, or rather 0.5 wt.-%. In the h. m. fraction of the wet mill-
tailings only 1.06 wt.-% of rutile and 2.43 wt.-% of ilmenite were contained (unpublished
notes, HGC).

According to Rove (1946) from April 1, 1944 to Dec. 1, 1945 8,832 tonnes of rutile
and 55,955 tonnes of ilmenite were extracted by HGC. After the installation of a zircon mill
(Hubbard, 1948) in August 1945 zircon was also extracted on own account, that was until
Dec. 1, 1945 1,731 tones, first from tailings, later also out of the ore sand. At this point of
time the average h. m. content of the ore sand was. only 4 wt.-% with a cut-off grade of 3 wt.-
% of h. m. On the average the h. m. fraction contained 51.4 wt.-% of ilmenite, 8.1 wt.-% of
rutile, and 12 14 wt.-% of zircon. The average mining thickness came to 3.8 m (12.5 feet)
without overburden.

Until the beginning of October 1944 some 0.726 Mt. of ore sand were mined by HGC
(Humphreys & Hubbard, 1945), according to Humphreys Investment Company (1946) until
the end of 1945 already 2.804 Mt. Until October 1948 this quantity was increased to about 8.2
Mt. (Hubbard, 1948) and until 1962 to about 55 Mt. (Cook, 1962).

Inl949 for the first time small quantities of monazite were separated (Calver, 1957),
whereby the content of monazite in the h. m. fraction was said to be 0.7 wt.-% (Mertie, 1975).
According to Meyer (1960) the production capacity in 1959 scarcely amounted to 44,000
tones of ilmenite and 14,000 tones of zircon per year. According to E. V. Whittle (pers.
comm., 1990) about 300 500 tones of monazite were extracted per year. Partially even
garnet was sold to interested customers.

While the mining by the RMCoF had been concentrated in particularly high-grade areas
in the north of the Jacksonville deposit, because of the technical modifications undertaken by
HGC, also low-grade areas could be mined (see Mertie, 1975). In the years from 1944 (1943)
to 1953 large parts of the deposit north of the Atlantic Boulevard (Highway 10) were mined.
Complete production installations came into existence along Mill Creek Road (see fig. 20).
There the h. m. were pre-concentrated in the wet mill and thereafter separated in the neigh-
boring dry mill. The extracted monazite was packed in sacks, while the ilmenite, rutile and zir-
con concentrates, were taken by trucks as bulk goods to the nearest railway station, some 8 km








away (Detweiler, 1952). Later on mining moved to the so-called Ingram-Merrill tract (see be-
low).
With the recalling of the Trail Ridge mining contract by Du Pont in 1958 the independ-
ent sale of zircon was stopped and all zircon taken from Du Pont (E. V. Whittle, pers. comm.,
1990).

It was planned to mine the Skinner Tract from the end of 1959 to the spring of 1966,
this tract being situated farther in the south where the h. m. deposit was covered, different
from the other tracts, by barren sands (see fig. 21). As early as on Sept. 15, 1958, however, in
this area the removal of the overburden had begun, on Oct. 2, 1958 the first ore sand was
mined, and on Nov. 24, 1958 the first h. m. concentrate out of this deposit was produced
(unpublished notes, HGC). As a consequence of the increasing distance to the main plant on
the Mill Creek Road it was decided to move the stationary wet mill into the center of the new
deposit and from then on to transport the produced h. m. pre-concentrate by truck to the dry
mill being situated 8.6 km to the north.
After the exhaustion of all accessible areas of the deposit the contract with TAMCO
was cancelled on Dec. 31, 1964 and all plants moved to Folkston in 1965, where mining
started by order of Du Pont (Garnar, 1972; Thompson & Whittle, 1990) in August 1 965.

It has particularly to be mentioned that in 1966/1967 the Carpco Engineering Company
returned to the tailings areas to produce and sell a monazite, and until then unique for Florida,
even a xenotime concentrate (J. Gully, pers. comm., 1991).

The h. m. composition of the Jacksonville ore sands was published only once
(Detweiler, 1952, repeated by Calver, 1957, and U.S. Bureau of Mines, 1987). Further infor-
mation could be taken from reports by RMCoF (1944) and Wood (1944) While having a closer
look at a wet mill h. m. concentrate from the Jacksonville plant, Miller (1945) erroneously
took the mineral enstatite, not occurring in Florida sands, for sillimanite.

Detweiler (1952) RMCoF (1944) Wood (1944) M~iller (1945)
ore sand ore sand are sand wvet mill cone.
ilmenite 40 % 38 % 39.2 % 26 %
leucoxene 4 %
rutile 7 % 12 % 10.5 % 5 %
zircon 11 % 15 % 15 % 3 %
kyait pesnt10 % 10 % 3 %
stauroliteprsn 6% pent21 %
sillimanite present
(enstatite) 24 %
ant rset1 % pent1 %
monazite < 0.5 % 0.5 % 0.5 % +
tourmaline reetreetrsnt6 %
mantie4 % rent+
eidote prsn resent 11 %
hornblende prsn resent 1 %


Tab. 12: H. m. composition of ore sands and of a wet mill concentrateof the Jacksonville
placer deposit after various authors.
All data in wt.-%. (+ = traces, less than 0.5 wt.-%)







After Mertie (1975) in the northern part of the deposit the ratio of ilmenite to rutile to
zircon was 4:1:1.5. Other minerals in the ore sands are said to have been staurolite, kyanite,
sillimanite, monazite (0.7 wt.-%), tourmaline, garnet, epidote, and xenotime.
Overstreet (1967) mentioned a monazite content of 0.5 wt.-% in the h. m. fraction.
After Cannon (1950) epidote and hornblende seemed to have been important.
In the zircon mill tailings besides 46.6 % quartz and 1.6 % not determined opaque min-
erals Browing et al. (1956) discovered 4.7 % kyanite, 8.5 % sillimanite, 4.2 % zircon, 20.2 %
staurolite, 4.2 % tourmaline, 5.8 % epidote, 1.8 % garnet, and 0.6 % rutile.
After Elsner (1992 a) in the tailings of the Jacksonville deposit also andalusite, topaz,
spinel, corundum, anatase, and chloritoid (!) can be found.

Using all available data the average h. m. composition of the Jacksonville deposit can
be assumed to have been as follows (tab. 13):

ilmenite 38 40 w~t.-%/ leucoxene 4 10 wt.-%/'
rutile 7 10 wt -% zircon 10 15 wt.-%/
monazite/xenotime 0.5 0 7 wt.-%/ staurolite 6 10 wt.-%
sillimanite 10 15 wt -% pdote 10 15 wt.-%/
tourmalinle 3 6 wt -%/ hornblende 1 5 wvt.-%/
toa 1 2 wt.-% kynit 3 wt-%/'
garnet wt.-%/ corundum < 1wt.-%
andalusite < 1wt -% anatase < 1wt.-%
spinel0. 1 wt.-% shn 0. 1 wt.-%
chloritoid 0.1 wt.-%

Tab. 13: Average h. m. composition of the Jacksonville placer deposit

The origin and age of the Jacksonville h. m. deposit is clear and can be given as
follows:

During the climatic optimum of the last interglacial (Sangamon) along the total Atlantic
coastal plain the Pamlico-sediment complex was formed (fossil average sea level height in-
cluding uplift: + 7.6 m). In this time a barrier island formed in the area just east of the city of
Jacksonville, having about the same dimensions as the Recent Amelia Island to the northeast.
West of this former ,,Jacksonville Island" there was an extensive salt marsh. On ,,Jacksonville
Island" big dune ridges came into existence in which the h. m. were concentrated in the shape
of (coastal) dune players, after having been pre-concentrated on the beach.

In the two northern mining areas the basis of the ore body lay at about 7.6 m (25 feet)
above msl. whereby a position of these ore sands in the Pamlico complex seems to be assured.
The maximum dune thickness was about 9 m. Compared to the relatively low-grade dune
players, high-grade beach players make up only a very small part of the present Jacksonville
deposit.

The beginning deterioration of the climate in the transition to the Wisconsin glacial ini-
tiated a slow regression of the sea level. The former salt marsh west of the ,,Jacksonville
Island" fell dry, later being used as a bed by the developing Johns River. The sea level only
sinking very slowly was favorable to the formation of an extensive beach ridge plain, now







clearly visible to the east on air photos and satellite images. The beach ridges in the south that
are concavely bending to the west thereby copy the shape of the former drumstick-shaped
,,Jacksonville Island".

During a later point of time (pleniglacial?) relatively h. m.-poor sands were blown in,
today covering older, mineralized dune sands with a thickness of more than 9 m in the southern
part (Skinner Tract) of the former ,,Jacksonville Island".

Simplified flow diagrams of the dressing procedure for the separation of the h. m. out
of the Jacksonville deposit applied by HGC were published by Humphreys & Hubbard (1945)
as well as by Thompson & Brown (1950). Very good presentations considerably more com-
prehensive can be found in Carpenter & Griffith (1960) and Giese et al. (1964) which is re-
ferred to here. A detailed description of the applied procedure was given by Detweiler (1952).

During the mining of the Jacksonville deposit some 115 to 150 persons were employed
by HGC (J. Gully, pers. comm., 1991). Each an ilmenite, a rutile, a zircon and a monazite con-
centrate were being produced. Small quantities of garnet were sold to individual customers.
Xenotime was separated from the tailings by Carpco Engineering after the end of mining.

Some, until now unpublished information regarding the h. m. content of the Jackson-
ville deposit, are known from various company's internal reports. The northern part, i. e. the
one above all mined in the 1940s, also called "northern deposit", was at that time arranged into
different tracts (see fig. 20).
By using data of various internal reports of HGC and RMCoF (i. e. Wood, 1944) an
average h. m. content of 4.7 wt.-% for the northern area of the Jacksonville deposit can be
calculated. Although the average ore sand thickness is said to have been some 6 m (20 feet)
according to Detweiler (1952), Mertie (1958, 1975) and the U.S. Bureau Of Mines (1987), a
figure of only 5 m (also see Pirkle, 1972) seems to be more probable. The mined area
amounted to about 988 acres (3.998 km2), about 40 acres of which were used by the RMCoF.

Tract #4 (Ingram-Merrill = 400 acres) together with another small tract (Anders = 16
acres) being situated in the middle of the Jacksonville deposit was called Ingram-Merrill Tract
(416 acres = 1.683 km2). According to an unpublished calculation by Humphreys dated May
27, 1946 its reserves (average h. m. content of 5. 1 wt.-%) amounted to 95,000 tones of il-
menite, 19,100 tones of rutile, and 23,000 tones of zircon. (Original data converted in metric
tonnes and assuming a mining recovery factor of 75 %.). Arnold (1957) carried out radiomet-
ric and magnetic measurements in the Ingram-Merrill and Skinner Tracts. According to these
an average ore thickness of 4.1 m with an average h. m. content of 4.8 wt.-%. can be calcu-
lated for the Ingram-Merrill Tract.







Mining data of the southernmost Skinner Tracts (A. C. Skinner = 426 acres, R. G.
Skinner = 24 acres, Anders = 94 acres) are very well known from Lewis (1954) and are in-
cluded in tab. 14

northern deposit Ingram-Merrill Skinner mined total
A (km2) 3.998 1.683 2.201 7.628 36.848
T (m) 5.0 4. 1 2.99 4. 1 4.1
V mil m) 19.990 6.900 6.581 31.275 151.077
W (t/m3) 1.60 1.60 1.60 1.60 1.60
Q (ML~) 31.984 11.040 10.530 50.040 241.723
P (wvt.-%r) 4.7 5.1 7.44 5.55 5.5
HM (Mt.) 1.503 0.563 0.783 2.752 13.295

Tab. 14: Economic geology of the Jacksonville placer deposit (further explanation see text)

The probable size of the complete Jacksonville placer deposit (,,Jacksonville Island")
indicated in tab. 14 was derived from maps and is a rather conservative assumption. According
to Lewis (1954) and Wood (1944) the weight factor W concordantly amounted to 1.60 t/m',
only Rove (1946) supposed a factor of 1.47 t/m'.

According to Cook (1962) approximately 1600 acres were mined by HGC until mid-
1962; there were added nearly 95 acres in the year 1964 (Whittle, 1965). With assumed 150
acres in the period from the middle of 1962 to the end of 1963, they amount to approx. 1,845
acres, to be added further the area of 40 acres mined by RMCoF, consequently 1,885 acres
(7.628 km2). This corresponds approximately to the theoretically possible mining area of 1,948
acres (northern deposit = 988 acres, Ingram-Merrill = 416 acres, Skinner = 544 acres). The
difference of more than 60 acres is probably due to existing roads at that time, which had to be
excepted from mining.

On the whole it can be stated that only a very small part (25 %) of the whole Jack-
sonville deposit has been mined. The chances for a continuation of the mining in the central
part of the deposit can be said to be very small because of the permanently increasing coverage
with buildings. However, the possibility has to be pointed out, that there exists another big
deposit only a short distance from the former mining areas (see chapter on history and future
of h. m. mining in northeastern Florida).







Yulee


Yulee is the name of a small but rapidly growing village in the northeast of Nassau
County, Florida, some 30 km to the north of the city of Jacksonville.
Between the village of Yulee and the St. Marys River respectively its affluent Bells
River in the north and northeast lie several ridges irregularly shaped. These ridges predomi-
nantly overgrown with turkey oaks, live oaks, pines and palmettos are separated from each
other by numerous flat swamps and small creeks. The sand ridges belong to the Atlantic
Ridges and are situated in the eastern region of the St. Marys Meander Plain (see fig. 20).
A detailed work concerning the hydrogeological conditions prevailing in this area were
presented by Spangler et al. (1989).

* The Crandall Ridge forms the northwesternmost of the so-called Yulee Ridges with eleva-
tions of more than 13 m above msl. It becomes four meters higher directly on the bank of
the St. Marys River where a steep bluff, the so-called Reids Bluff, was formed by erosion.
The Crandall Ridge reaches a maximum width of 2.2 km, and a length of 4.2 km (area of
the h. m. deposit: 4.634 krn2)

* Two kilometers farther to the east follows another ridge, called Bells Ridge, with elevations
of more than 15 m above msl. To the north it borders on the meandering Bells River where
also a steep bluff, the so-called Bells Bluff can be found. Another bluff, the Roses Bluff, is
situated approximately 1 km northwest of the Bells Bluff.
The Bells Ridge is divided into several hills being separated by swampy areas. On the high-
est of them in the south a trailer park has been established. In this area the Bells Ridge is
bordered in the west by the McQueen Creek, the Lofton Creek in the south and the Blounts
Branch in the east. The area of the h. m. deposit comprises 8.984 km2

* Some 100 m farther to the east follows an extended sand ridge, reaching elevations of 12 m.
This ridge shall be called Haven Road Ridge. The area of the ore deposit formed in it was
determined with 2.377 km2.

* In the south of the settlement Chester at the Bells River the biggest of the four ridges con-
taining h. m. can be found. Along its total length of 12 km runs the Chester Road so that the
name Chester Road Ridge was chosen for it. This Chester Road Ridge forking in the north
is remarkable lower than the other three ridges and reaches elevations of only 9.5 m above
msl. It is crossed by several roads of various sizes and is characterized by numerous
swampy areas (ore deposit: 13.733 km2)

Most of the area is owned by ITT Rayonier, Inc. and is used for forestry. In other parts
more and more holiday houses, small settlements, churches and cemeteries come into exist-
ence. It is striking that many properties, also outside the forestry areas, are not accessible for
the public.

According to Pirkle et al. (1984) the Yulee h. m. deposit was discovered by the already
mentioned Chief Geologist of Du Pont, Dr. J. L. Gillson, at the beginning of the 1950s. For the
first time the location of the new discovery was published in 1959 by Gillson in a map of all
known h. m. deposits of the southeastern USA.
Lynd & Lefond (1975, 1983) indicated that the h. m. deposit was explored by different
companies, among them only "lately" by the Pennsylvania Glass Sand Corporation, a subsidiary







of ITT Rayonier, who owns most of the area. Exploration data of these companies also built
the basis of the monography on the Yulee deposit by Pirkle et al. (1984).

One of the other companies drilling in the Yulee Ridges was HMC. 266 holes were
drilled in this area from Nov. 30, 1970 to March 12, 1971, partly up to 9 m (30 feet) deep.
From each drill hole mixed samples were taken in 2-feet-intervals (surface: 4 feet) and checked
for total h. m. and the TiO2 COntents.
The complete documents of this exploration campaign were gratefully put at the
author's disposal by E. V. Whittle in 1991. Nearly all economic-geological information of this
chapter (see below) originate in the evaluation of the 257 (of formerly 266) drill holes, of
which the exact location could still be determined precisely after more than 20 years.

According to the mutual opinion of all exploration geologists working in northeastern
Florida: the Yulee deposit will never be mined. The reason for this is less the volume of the
deposit than rather the competitive use of the area by the rapidly growing population around
the village of Yulee (Dr. E. C. Pirkle, Dr. F. L. Pirkle, J. C. Reynolds, E. V. Whittle, T. E.
Garnar; J. M. Elder, pers. comm., 1990).

The age and origin of the Yulee Ridges can be summarized as follows:

During the last interglacial (Sangamon) on the whole Atlantic coastal plain a transgres-
sion took place, the so-called Pamlico transgression. At that time a barrier island was formed in
the northeast of present-day Yulee on the southern bank of the former mouth of the St. Marys
River. Today this barrier island is still preserved in form of the Bells Ridges (compare Hud-
diestun, 1988). By the formation history of this former Bells Island the sediments being made
accessible today in the Bells Bluff are typical of a regression (prograding barrier island se-
quence). To the west of the former Bells Island a salt marsh was formed (base of Reids Bluff),
to the north there was the tidal inlet (base ofRoses Bluff) of the St. Marys River.

With the beginning regression first the salt marsh and a little later also the tidal inlet fell
dry. At the climax of the second short-time transgression at the end of the Sangamon
interglacial (Princess Anne transgression) another barrier island was formed. Also on this bar-
rier island h. m. were concentrated in dunes. In the inland area of this Chester Road Island the
dune complex of the Crandall Ridge, in which the h. m. are also present as eolian players, came
into being.

According to Mallard (1986) the Yulee Ridges formed as mesotidal, drum-stick shaped
barrier islands dominated by tides similar to present-day Amelia Island. Also Pirkle et al.
(1984) compared the former Yulee barrier islands with the Recent Amelia Island (see fig. 23).
There would, however, be more justified a comparison of the fossil Yulee Ridges, consisting of
,8ells Island" (Pamlico) and ,,Chester Road Island" (Princess Anne) with Big Talbot Island
(Silver Bluff) and Little Talbot Island (Recent) that one time in the future could build a kind of
Talbot Ridges. Amelia Island (Silver Bluff core) on the contrary shows strong similarities with
the former ,,Jacksonville Island" (see above) (Pamlico and Princess Anne?).








Pirkle et al. (1991b) Groszet al. (1989) Elsner (1992a)
ilmenite 52.7 % 31.2 % 28.7 %
leucoxene 2.2 % 4.6 % 8.7 %
rutile 7.4 % 10.2 % 2.7 %
zircon 16.0 % 8.3 % 5.5 %
eiote 6.6 % 7.5 % 26.2 %
sillimanite 5.4 % 10.3 % 10.7 %
kynie1.3 % 2.5 %
staurolite 5.2 % 12.2 % 7.2 %
tourmaline 2.3 % 5.7 % 2.5 %
hornblende 0.8 % 0.4 % 3.0 %
garet0.4 % 1.0 %
others 0.3 %
monazite 2.0 % < 0.1 %
xenotime < 0. 1 %
andalusite 0.2 %
topaz0.5 %
corundum .0.2 %
shene 0.1 %
chloritoid < 0. 1 %
anatase 0.2 %

Tab. 15: Average h. m. composition of the Yulee placer deposit after various authors (all data
in wt.-%).

Whereas the calculations of T. E. Garnar (cited in Pirkle et al., 1991 b) correspond to
the average values of all ore sands (dune and beach players), the data (3 samples) given by
Grosz et al. (1989) as well as by Elsner (1992 a) (4 samples) reflect the h. m. composition of
the less mineralized dune sands close to the surface (leucoxene and epidote contents!).

Because of the data of the exploration campaign of HMC at the beginning of the 1970s
put at the author's disposal by E. V. Whittle, it was possible to calculate the ore volume of the
individual mineralized Yulee Ridges quite precisely (see tab. 16).

Crandall R. Bells R. Haven Road R. Chester Road R. total
A (km2 4.634 8.984 2.377 13.733 29.729
T (m) 3.55 2.97 2.44 2.94 3 .00
V (mill. m') 16.452 26.683 5.800 40.375 89.311
W (t/m ) 1 60 1.60 1.60 1.60 1.60
Q (Mt.) 26.324 42.693 9.281 64.600 142.898
P (wt.-%o) 3.34 3.37 2.96 2.92 3.12
HMI~ (Mt.) 0.879 1.439 0.275 1.886 4.479

Tab. 16: Economic geology of the Yulee placer deposit







The only other values comparable to the ones calculated above were presented by
Pirkle et al. (1984) who indicated an ore volume of Aipprox. 1.2 mill. short tons (1.089 Mt.)
TiO2, an Ore deposit size (A) of approx. 5,000 acres (20.234 km2) and an ore sand thickness
(T) of approx. 9 feet (2.75 m). Applying a TiO2 COntent of 1.13 % in the ore sand (calculated
by data from the HMC exploration campaign) an ore volume (Q) of approx. 96.3 Mt. of ore
sand with approx. 3 Mt. of available h. m. can be calculated.
T. E. Garnar (pers. comm., 1990) on the contrary assumed the h. m. content of the
Yulee placer deposit to be approx. 5 mill. (short?) t. of h. m.









Amelia Island, located at the southern end of the Sea Island Chain, is the biggest of the
two barrier islands of northeastern Florida. With a length of more than 21 km and a width of
up to 4 km its highest elevation is more than 10 m above msl. The core of the island, at the
same time the geologically oldest part of the island, is situated in the west and borders on the
wide salt marsh of the Amelia and South Amelia Rivers. In its northern part the small town of
Fernandina Beach founded in 1567 extends with its historical city center (see fig. 23).

The beach but also dune players of Amelia Island have been known for many years
(Overstreet, 1967) and were explored by the U.S. Bureau of Mines (Marshall, 1954; Peyton,
1955) and numerous private companies (Mertie, 1958, 1975). In the south of Amelia Island a
large property belonging to Union Carbide was drilled in the mid-50s by HGC. The
h. m. ore body found was to be mined as early as 1957 by the Union Carbide & Carbon Corpo-
ration (Giese et al., 1964; Mining World, 1955 b). For this purpose an old dredge dismantled in
parts as well as a Cannon circulator concentrator for the dry mill already waited in Fernandina
Beach for their recall (E. V. Whittle, pers. comm., 1990). In August 1957, however, world
market prices for titanium minerals began dropping drastically (Mertie, 1958, 1975; Garnar,
1980), so that mining was postponed for an undefined time.

At the end of 1969 Union Carbide contacted Du Pont in order to negotiate about the
production of h. m. concentrates (ilmenite, rutile, zircon, monazite, according to Overstreet,
1967) that still remained unmined. Investigations by Du Pont, however, proved the non-
feasibility of the planned enterprise so in mid 1970 it was decided to drop all further mining
plans.

Since Union Carbide then was no more interested in its property on Amelia Island, the
whole area with a size of 3,300 acres (13,355 km2) was sold to the Sea Pines Company of
Hilton Head Island, SC (T. E. Garnar, written comm., 1991). During the following years the
above-mentioned company turned its new property into a luxury resort with tennis-courts and
golf courses, apartment buildings as well as shopping centers (Garnar, 1972, 1978a, b, 1980).
The value of this meanwhile well-known property named Amelia Island Plantation, exceeds the
value of the h. m. being latent under it by all means.

Nothing is known about the granulometry or the depositional origin of the former ore
sands, but according to descriptions by Mertie (1975), above all, it must have been dune
players. Referring to his descriptions the ore sands reached an elevation of up to 7.6 m (25
feet) in the center of the deposit, dipping to the east and to the west down to the present msl.
The average h. m.. content of the ore deposit is said to have been 3 wt.-% (Mertie, 1975).
Other figures were given by Pirkle et al. (1984) and T. E. Garnar (written comm., 1991) with
approx. 4 wt.-%, or even 11 wt.-% (Mallard, 1986).

The average h. m. composition of the former ore deposit is known by T. E. Garnar
(written comm., 1991) and can be compared with data given by Eichenholtz (1986) respect-
ively Eichenholtz et al. (1989) of the beach ridge plain north of Fernandina Beach (74 samples
of 30 drill holes) and by Peyton (1955) of 32 drill holes along highway A1A.


Amelia Island








Garner (1991) Pyo (1955 Eichenholtz (1986)
h. m. rae2.00 % 1.0 1 %
ilmenite 37.0 % 49.2 % 50 28 %/
leucoxene 9.7 %/ 1.91 %
rutile 4.6 %/ 5.3 %/ 2.63 %/
zircon I 1.2 %/ 10.7 % 6.6 1 %
monazite/xenotime 0.2 %, 0.7 %
staurof ite 6 9%O/ 5.5%0/ 3.18 %/
tourmaline 2.7 % 1 45 %/
kyanite 6 4 % 1.7 % 6.02 %/
sillimanite 3 8%
garet0.6 %/ 2.2 %/ 1.48 %/
eidote 20.3 %/ 16.4 % 22.3 1 %
hornblende 0.3 % 4. I 3 %/
mica 1.8 %
collohn 1 5 %/
others 1.3%


Tab. 17: Average h. m. composition and grade of sands of different areas
after various authors (all data in wt.-%).


of Amelia Island


Only little is known about the size of the ore body, which was planned to be mined by
Union Carbide on Amelia Island. According to E. V. Whittle (pers. comm., 1990) the ore
deposit stretched from close to the airport near Amelia City over American Beach, in its cen-
ter, south to Franklintown.
After Mallard (1986) the original area of the ore deposit measured approximately 10
km x 1.5 up to 2.5 km, with an average thickness of 1.8 m (6 feet). An area of close to 8 km2,
however, according to indications given below seems to be more probable.
According to Peyton (1955) dredging down to an average depth of 3.1 m would have
been possible.

According to Pirkle et al. (1984) the volume of the deposit amounted to 320,000 short
tons ofTiO2. T. E. Garnar (written comm., 1991) gave the same figure (cut-offgrade: 3 wt.-%
h. m.) also mentioning an average h. m. content of 4 wt.-% and an average TiO2 COntent of
62.5 % in the titanium minerals, which, on the other hand, made up 51.3 wt.-% of the h. m.
fraction. From these data a volume of the original deposit of some 0.9 Mt. of h. m., respec-
tively 23 Mt. of ore sand may easily be calculated.
Union Carbide planned to produce 30,000 tons of ilmenite and 5,000 tons of rutile per
year.

According to Peyton (1955) the average TiO2 COntent of the Amelia Island ilmenite
was 58.4 %. The monazite of Amelia Island was said to contain 4.83 % ThO2 and 0.58 % of
U30s.
According to T. E. Garnar (written comm., 1991) the chemical composition of the
ilmenite (81 % of the titanium minerals) was analyzed to be 58 % TiO2, 15.2 % FeO and 21.4
% Fe203. Leucoxene (13 % of the titanium minerals) contained 74 % TiO2, rutile (6 % of the
titanium minerals) consisted of 98 % TiO2.










Little Talbot Island is the southernmost island of the Sea Island Chain south of Amelia
Island. The island being 7.2 km long and just more than 1 km wide comprises an area of
approx. 6.9 km2. It is built up by elongated N-S-trending beach ridges vihich are covered by
dunes, reaching elevations of more than 6 m above msl. (see fig. 24).
The whole island belongs to the state park system of Florida (Little Talbot Island State
Park) where any commercial use is strictly prohibited. The Atlantic beach of the island is
known as one of the most beautiful beaches of the USA.
Because of the restriction to a few touristic activities Little Talbot Island practically is
an untouched barrier island where natural enrichments of h. m. can excellently be observed in
nature.

Already when reaching Little Talbot Island on highway A1A black veils of h. m. on the
dunes bordering the highway strike the eye. For this reason it did not remain a secret to the
companies exploring in Florida that the whole island was rich in h. m. (Mertie, 1975), and al-
ready in 1946 Rove (p. 2.) reported: "Du Pont has apparently spent from $ 75,000 to
$ 100,000 this year (1945) in a non-productive search. They claim that Little Talbot Island is
one of the best looking shore prospects they have seen."
In the 1950s also exploration teams of the U.S. Bureau of Mines were making their
way onto the island. At least some data are known of their reports (Marshall, 1954; Peyton,
1955). A short time later the island was declared a State Park and thereby forever withdrawn
from the grip of the mining companies.

Peyton ( 195 5) Peyton (1955) Eichenboltz ( 1989)
Big Talbot island Little Talbot Island Little Talbot Island
number of samples n =4 n = 1 1 n = 74
b. m. rae1.05 % 1.92 % 7.00 %
ilmenite 48.7 % 42.2 % 53.20 %
leucoxene 1.37 %/
rutile 4.1 %/ 3.4 % 4.92 %/
zircon 10.0 %/ 6.6 % 14.68 %/
monazite 0.5 % 0.5 %
staurolite 6.7 %/ 4.7 % 4. I3 %
sillimanite 5.0 % 4.0 % 5.66 %
kynie 2.7 %/ 1.9 %
eidote 17.3 % 22.6 % 12.32 %
hornblenlde 0.3 % 1.7 % 1.29 %
tourmaline 2 2 % 3.0 %/ 0.52 %
garet2.4 %/ 1.4 %/ 1.70 %
clohanes 0.1 %80%


Little Talbot island


Tab. 18


: Average h. m. composition and grade of sands of Little i
Peyton (1955), and Eichenholtz (1989) (all data in wt.-%).


and Big Talbot Islands after


Only a few years ago the h. m. composition of the sands of Little Talbot Island were
the object of scientific investigations again (Eichenholtz, 1986; Eichenholtz et al., 1989). Be-
cause of the insufficient analytical methods used it seemed to be advisable, however, to take at







least some new samples which were analyzed according to procedures described. in detail by
Elsner (1992 a).
One of the granulometrical findings was that the average grain size of the beach sands
of Little Talbot Island decreases from north to south, whereas the sorting~gets better.
Mineralogical findings are even more interesting, as the blackish veils of h. m. seem to
be more greenish-blackish, the color coming not from high monazite, but rather hornblende
and above all epidote contents. Samples taken from deeper holes confirmed the possibility of a
continuous mineralization of the island with a considerable amount of the h. m. always being
epidote (see fig. 25).
Concentrations of nearly only the heavier, i.e. the more economic h. m. are to be found
in the upper backshore area. These storm-built concentrations reach thicknesses of only 1 to 2
decimeters. A continuous seam can best be observed in the north of Little Talbot Island,
whereas to the south a splitting into several a little bit thinner layers takes place.

Although a mining of the h. m. was for all times prevented after the integration of Little
Talbot Island into the Florida State Park System, the ,,theoretical" h. m. content of the island
can be calculated.
As already amplified, obviously the whole island (6.9 km2) is mineralized, whereby an
average dune sand thickness of approx. 3 m is reached. On Little Talbot Island are hence found
20.7 mill. m3 of ore sand corresponding to 33.1 Mt. of ore sand at a (dune sand) weight factor
of 1.60 t/m'.
According to Eichenholtz (1986) the average h. m. content of the dune sands can be
calculated with 7.00 wt.-%, according to Elsner (1992 a) it can be given as even 8.27 wt.-%.
The absolute h. m. content of the beach sands (not regarding the storm-built players) probably
is still lower than the average value of 4.98 wt.-% calculated by Elsner (1992 a). On the other
hand an average h. m. content of 1.92 wt.-% as indicated by Peyton (1955) definitely seems to
be too low.
Using the data given by Eichenholtz (1986), based on the counting of 74 samples, an
ore content of 2.3 Mt. h. m. (on a conservative basis) can be calculated, of which only a bit
more than 1 Mt. should consist of economically interesting minerals.







Ponte Vedra Beach (Mineral City)


North of the St. Johns River far into the Carolinas barrier islands of the Sea Island
Chain form the Atlantic Coast of the southeastern USA. South to Miami Beach elongated
beach and dune ridges can be found, being separated from the mainland by lagoons or the
Florida Intracoastal Waterway. The structure of the above mentioned beach and dune ridges is
very similar along the whole Atlantic coast: an approx. 200 m wide and up to 10 m high dunal
belt is joined on its seaward side by a gently descending beach, in case of low tide, 150 m wide
on the average. On its landward side the coastal highway A1A can be traveled to enjoy the
coastal scenery.

The beaches that have been investigated more closely by Elsner (1992 a) belong to two
sections, the southern one comprising all of 23 km long Anastasia Island. The northern part of
the northern section (55 km), stretching from Mayport at the St. Johns River mouth south for
15 km along the coastal towns of Atlantic Beach, Neptune Beach and Jacksonville Beach is
characterized by artificial beaches (Dr. W. F. Tanner, pers. comm., 1990) and, therefore, was
not studied in detail. South to this section relatively pristine beaches can still be found, which
have been known for their h. m. enrichments for quite a long time.

According to Liddell (1917) Henry H. Buckman and George A. Pritchard were the first
to carry out an investigation of the industrial minerals of Florida at the beginning of World War
I. Investigating one of their sand samples they found a striking concentration of ilmenite which
startled them quite a bit. In order not to enter an unlimited market, they had a closer look at all
the beaches between Savannah, SC and the southern tip including the Gulf beaches of Florida
without, however, discovering any other deposits of this mineral. The highest concentration of
h. m. was detected between the St. Johns River in the north and St. Augustine in the south
with its center near the present-day Ponte Vedra Beach.
Together they founded a mining company, named it Buckman and Pritchard Inc., and
bought a property on which plants and administration buildings were erected. This settlement
soon got known by the name of Mineral City.

Near Mineral City the beach was approx. 160 m wide at low tide, giving way to 4 m
high and up to 60 m wide dune ridges to the west (Liddell, 1917). Those parts of the dunes
containing the most h. m., and all the storm-placers in the foredune area having an average
concentration of 20 wt.-% h. m. were being mined.

Mining started in 1916 first on sands with an even considerably higher h. m. concentra-
tion. These were the sands of the so-called "friendship vein", reaching a maximum width of
21 m (70 feet) and an average thickness of 2.7 m (9 feet). According to Liddell (1917) this
,,friendship vein" was even underlain by another 2.4 m (8 feet) of only little lower-graded
players. Martens (1928), however, after visiting the plant site by himself, considered these data
as completely exaggerated and reported a thickness of only 60 to 75 cm, a width of 7.6 to 10.7
m and a h. m. concentration in the darkest storm-placer layers of up to more than 60 wt.-%.
Everyone visiting the beaches near the former Mineral City site nowadays will clearly see that
the data, given by Martens (1928) are much more probable than those by Liddell (1917).

At the beginning of mining only ilmenite was of interest, being processed to titanium
tetrachloride, which was used for tracer bullets, spotting shells, and smoke screens (Martens,
1928; Calver, 1957; Peterson, 1966; Garnar, 1972, 1978 a, b; U. S. Bureau of Mines, 1987).







During those early years also very small quantities of monazite and zircon were said to
have been extracted (Liddell, 1917, p. 155). According to Overstreet (1967), however, the
maximum production of monazite was reached in 1925 with only approx. 900 kg.

After the end of World War I production declined considerably. In 1922 Buckman &
Pritchard, Inc. were bought by the National Lead Company, from then on considered a sub-
sidiary of the last mentioned company which is much larger. With the take-over in 1922 also
for the first time in Florida the large scale separation of zircon began. All the zircon concen-
trates produced were used in the refractory industry, for which National Lead held a US pat-
ent. In 1925 rutile followed as another mineral being separated for the first time (Martens,
1928; Gillson, 1949; Calver, 1957; Meyer, 1960; Overstreet, 1967; Garnar, 1980, 1985).

Although the different h. m. first were only extracted from the ore sands alone, with
time the old tailings grew in importance (Thoenen & Warne, 1949, details in Martens, 1928).
In this way a second climax of production at the end of World War I was reached in 1927
(Calver, 1957; Garnar, 1980).
Only a short time later, however, in 1929, the mining of h. m. out of the beach sands
near Mineral City was completely stopped. According to Calver (1957) this was caused both
by the exhaustion of the h. m.-rich parts and the hard competition by Indian and Australian
producers. Neither should the beginning of the Great Depression in that year be neglected.

During the 13 years of production between 1916 and 1929 the mining near Mineral
City had proceeded north for approx. 5 km. The h. m. rich layers extended still farther, but
mining was not possible due to the bathing activities in that area. Into the other direction
mining had extended to the south for even 13 km, and a continuation was planned in spite of
much lower grades (Martens, 1928; Overstreet, 1967).

After closure of the production plants Buckman & Pritchard, Inc., still in possession of
National Lead Company, was renamed into Ponte Vedra Company. This company recultivated
the former mining site, using the old tailings and mining ponds for the design of a large golf
course. In 1942 the whole property was sold and the present-day luxury settlement of Ponte
Vedra Beach was developed (Calver, 1957; Garnar, 1972, 1978 a, b, 1980). Today's center of
Ponte Vedra Beach, the Ponte Vedra Country Club and Golf Course, is situated exactly in the
center of the former mining site.

70 years ago the separation of h. m. from the Mineral City deposit was quite different
from operations today. A floating dredge operating in the dunes had only a very low capacity.
The majority of the h. m. in the beach sands, therefore, was loaded on trucks with a shovel and
hauled to the wet mill in Mineral City (Spencer, 1948). For a short time also a narrow-gauge
railway as a means of transport was in action (Liddell, 1917; Martens, 1928).

In the wet mill the natural h. m. concentrate containing 20 wt.-% of h. m. on the
average, according to Spencer (1948) 28 wt.-% of h. m., was mixed with water and handled
over 18 shaking tables. The wet mill concentrate produced with a recovery factor of 75 % on
the average is said to have contained on the average 55 % of ilmenite, 20 % of zircon, 6 % of
rutile, 2 % of monazite, 14 % of other h. m. as well as only 3 % of light minerals (quartz, feld-
spar, shell fragments). A single sample of this concentrate checked by Martens (1928) even
contained 98.5 % of h. m.. After the determination of 3174 (!) grains he was able to give the
following list:







46.5 % of ilmenite,
0.5 % of leucoxene,
9.9 % of rutile,
3.6 % of monazite,
2.2 % of staurolite,
2.8 % of epidote,
0.9 % of garnet,
0.2 % of sillimanite,
0.1 % of tourmaline,
0.2 % of hornblende,
0.1 % of sphene,
0.1 % of spinel,
0.2 % of collophanes
as well as traces of corundum and anatase.

Afterwards this wet mill concentrate was dried and by magnetic and electrostatic sepa-
ration an ilmenite concentrate was being produced. The non-magnetic part was then handled
over further wet shaking tables. By this new concentration on the shaking tables most of the
remaining light minerals as well as the Al-silicates could be separated. Remaining rutile was
separated electrostatically from the zircon and each a rutile and a zircon concentrate produced
by the use of even more shaking tables and magnetic separators. Ilmenite and zircon were sold
as bulk goods as well as rutile in sacks to the Titanium Pigment Company, Inc. of St. Louis,
Missouri that took over also the processing of the zircon.

A calculation of the probable original volume of the deposit is only possible in a gen-
eral way. As key parameters a total length of the h. m. players of 40 km from Jacksonville
Beach in the north to Vilano Beach in the south can be assumed. Theoretically the maximum
widths of the beach players could have been approx. 10 m (on the average 20 wt.-% of h. m.)
and approx. 200 m (on the average 2.42 wt.-% of h. m., according to Peyton, 1955) of the
dune players. According to Martens (1928) the beach sands were mineralized down only to the
elevation of the sea level (= thickness of 2 m), whereas according to Peyton (1955) the average
dune thickness was 4 m. Finally calculating the weight factor (W) according to Macdonald
(1983: p. 61) the following values result:

beach dunes total
A (kmn') 0.400 8.000 8.400
T (m) 2.0 4.0 3.9
V (mill. m') 0.800 32.000 32.800
'W (t/m'j) 1.82 1.62 1.60
Q (Mt.) 1.456 51.840 53.296
P (wt.-%/) 20.0 2.42 2.85
HM (Mt.) 0.291 1.255 1.546

Tab. 19: Economic geology of coastal placer deposits along the Recent Atlantic coast between
Jacksonville Beach and Vilano Beach








In contrast to the values given above there are the calculations by Liddell (1917) with
30 to 39 Mt. of ore sand of a considerably shorter beach section. Based on Liddell's data Over-
street (1967) stated an original monazite content of the Mineral City placer deposit of 4500
tonnes.







Offshore


The offshore area stretching out in front of the Atlantic coastal plain has been the sub-
ject of intensive geoscientific research for nearly 25 years. For this work, however, neither the
stratigraphy in several hundred meters depth nor the partially complicated structure of the con-
tinental shelf off Florida is of any meaning.
Turning to the sedimentological conditions off the coast of northeast Florida the fol-
lowing picture can be described:

Within a few meters of water depth the relatively steeply sloping shoreface zone turns
into the nearshore area being characterized by numerous shoals respectively bars. According to
detailed investigations by Meisburger & Field (1975) this nearshore zone is built up by fine to
very fine badly sorted silty quartz sands with a thickness up to 2.5 m (,,shoreface facies"
according to Meisburger & Field, 1975). The mica content partially is very high, also mollusk
fragments can make up for 20 % of the sediment. Feldspar, h. m. and phosphorite nodules can
be found only subordinately. Down to water depths of 5 10 m the bottom of the shelf is
strongly mottled due to bioturbation (Howard & Scott, 1983). The already mentioned shoals
reach a height of up to 6 m and principally are build up by sand (Nocita et al., 1990).

In water depths between 14 to 17 m a sedimentological change takes place to fine to
coarse, well to badly sorted light gray sands. These quartz sands contain up to 15 % of
carbonate in form of mollusk fragments. The feldspar content was found to be between 0.5 and
4 % with an average of 1.5 %. The number of phosphorite nodules increases, while the mica
content decreases considerably. Heavy minerals again can be found only in traces. The thick-
ness of these sands of the ,,inner shelf facies" (Meisburger & Field, 1975) varies between 30
and 90 cm, only sporadically a thickness of 2.5 m is reached.

Below the sands of the ,,shoreface" and the ,,inner shelf facies", respectively, brown,
dolomitic-silty or white, foraminiferous quartz sands can be drilled. These sands both belong to
the ,,residual facies" (Meisburger & Field, 1975) that also makes up for the bottom of the sea
floor farther offshore, with water depths 24 m and deeper.

The flat offshore area off northeastern Florida represents a continuation of the Atlantic
coastal plain that is itself only a shelf fallen dry (Grosz et al., 1986). Having been known for a
long time this fact has, of course, provoked speculations regarding the h. m. content of the
Recent shelf since the beginning of h. m. mining in Florida. Above all in submarine elongated
sand ridges, i. e. inundated glacial sediment complexes it was expected to find h. m. players.
Also shoals of all kinds and inundated glacial river beds were said to contain h. m. deposits
(Zellars-Williams Company, 1988). As especially interesting some considered those regions
where also onshore h. m. deposits had been found (Emery & Noakes, 1968; Kudrass, 1987).

Already in 1954 (Rock Products) an exploration permit for h. m. off the coast of
northeastern Florida was granted without, however, any find later being reported. In the 1960s
and 1970s in the frame of general investigations of the sea bottom floor the absolute h. m.
content of the shelf sediments was analyzed in more detail. Both Pilkey (1963) and Henry &
Hoyt (1968) reported average h. m. contents of less than 0.5 wt.-%.

Without allowing to be influenced by such reports the U.S. Geological Survey carried
out further investigations in the past years off the whole Atlantic coast, thereby also testing
new geophysical exploration methods (Grosz & Escowitz, 1983; Wynn & Grosz, 1986; Grosz








et al., 1986; Grosz, 1987; Nocita et al., 1990). With only few exceptions, however, no h. m.
enrichments being worth mining could be found.

Of course, the mining companies exploring in the southeastern USA were not inactive
and also carried out independent offshore exploration programs, their specific results being
treated as confidential without any exception. It is, however, generally known, that nowhere
off the Atlantic coast sediments enriched in h. m. were discovered which by any economic con-
stellation would justify considerations regarding possible mining (WI. L. Evans, pers. comm.,
1990, in contrast to that: Grosz et al., 1986 and Grosz, 1987).

As already mentioned until today no h. m. players at all have been found off the coast
of north-eastern Florida. The highest h. m. content ever published is 2.40 wt.-% (Grosz et al.,
1986; Grosz, 1987). Also in the future discoveries of h. m. deposits worth mining are not to be
expected. For this opinion a number of reasons can be given:

1) Most of the world-wide known coastal players formed by the reworking of fluvial and
littpers. sands that were deposited during the glacials on the Recent shelfs. Thereto Riggs &
Belknap (1988: p. 57) wrote: "Thus, regressions create temporary storage of new sediment
on the shelf, while transgressions extensively rework these sediments, carrying some shore-
ward with the coastal system and losing some seaward to the slope." As nearly no material
for reworking was available during the glacials in times of lower sea level, the coastal sedi-
ment complexes formed during that time might have been fundamentally thinner and corre-
spondingly might have contained far less h. m.

2) On one hand by the reworking of glacial littpers. sediments the early Holocene transgression
has created the basis for Recent coastal players, on the other hand by this reworking it has
considerably reduced the probability of the conservation of former beach players on the
shelf floor.

3) Climate in the glacials neither favored an extensive alteration of ilmenite into leucoxene nor
the weathering of the ,,disturbing" minerals hornblende, epidote, pyroxene and magnetite.
Possible placer deposits hence might contain high fractions of economically non-interesting
h. m. components.

4) To discover already quite large deposits like Green Cove Springs on the shelf can be com-
pared with the search for a needle in a haystack. Besides, drill campaigns have to be limited
to a coarse pattern with distances of at least several kilometers between the drill holes be-
cause of the immense areas to be covered.

5) Geophysical exploration methods of the shelf are still at their beginnings (Wynn & Grosz,
1986) and have until now not fulfilled any of the optimistic hopes for a cheaper, faster and
at the same time more reliable exploration activity (WV. L. Evans, pers. comm., 1990).

6) Barrier islands of early Holocene age being possibly rich in h. m. were only be detected
solitarily in form of erosional remains off the coast of northeastern Florida.

7) Off the northeastern Florida coast covering economically completely uninteresting Tertiary
sediments lie only very thin sand layers whereby the discovery of thick h. m. deposits is
excluded from the beginning.







8) Until today governed by natural and legal restrictions exploration activities have been
carried out nearly only on the outer shelf outside the three-miles-zone. Only within a few
kilometers or rather hundred meters off the coast, however, those physical processes occur
on the sea floor which might eventually lead to a settlement of larger amounts of h. m. (Dr.
P. Lee, pers. comm., 1991).

Should the search for h. m. on the shelf be continued in spite of all these restrictions, it
is recommended to yield to areas much closer to the coast. Good exploration objectives might
thereby offer the island bases, the possibly larger nearshore bar systems off those islands as
well as, above all, the shoals in front of the river mouths. Especially the latter might perhaps at
least fulfill some of the ambitious hopes that are often connected with the search for h. m. in
the offshore zone.

Although, as already pointed out for several times, no submarine h. m. deposits worth
mining off the Atlantic Coastal Plain have been discovered until today, techniques for possible
mining in the offshore zone are already known. Detailed, but of course completely theoretical
essays about this subject are to be found in Harvey & Brown (1986), U. S. Bureau of Mines
(1987) and Zellars-Williams Company (1988).








History and future of heavy mineral mining in northeastern
Florida

The first h. m. players of the USA were mined in Cleveland Co., North Carolina, start-
ing in 1895. Their monazite was used for the production of thorium, which was needed for the
manufacture of incandescent gas lights. .By the spread of electric lights these first h. m. mining
operations in the USA came to a sudden stop in 1916 (Garnar, 1980).

The need of another mineral, on the other hand, initiated the beginning of h. m. mining in
Florida. This mineral was ilmenite, which titanium, converted to titanium tetrachloride, found
several "applications" during World War I (see chapter on Ponte Vedra Beach). This
potential demand was answered by Henry H. Buckman and George A Pritchard by the opening
of their: operations south of Jacksonville Beach, which soon got known under the name
Mineral City. There, typical high-grade beach players and adjacent strongly mineralized dunes
were mined mostly by hand.
At the end of World War I the market for ilmenite collapsed and in 1922 the former inde-
pendent company Buckman & Pritchard Inc. was bought by the former National Lead Com-
pany and its operations continued as a subsidiary. After this change of ownership for the first
time ever zircon was commercially produced in Florida, which was exclusively sold to custom-
ers in the refractory industry. Rutile, for the first time separated in 1925, was converted by
National Lead into titanium dioxide and used as a raw material for the rapidly growing pigment
industry. Also in 1925 monazite was first commercially produced in Florida.
Although the market for h. m. steadily increased during the following years the mining
operations in Florida were stopped in 1929. This stop was caused by the depletion of the h. m.
rich beach players and the strong competition of Indian producers. In the '30s mining of h. m.
started on the Australian east coast, increasing the supply even further. Not till 1939, with the
beginning of World War II, the demand for h. m. increased again.

The first who answered to these changing market conditions was again George A. Prit-
chard. This time he was mining h. m. players for the Riz Mineral Company on both sides of the
Indian River (Brevard and Indian River Co.) between 1939 and 1943 (Mlertie, 1958, 1975).
The
minerals ilmenite, zircon, and monazite were separated in a mill near Palm Bay, 4 km south of
Melbourne, Brevard Co. With the depletion of these beach players at the Indian River, the
operations changed to dune players, which were mined starting in September 1943 south of
Vero Beach, 5 km onshore.

Meanwhile the war had expanded and the supply routes from Australia and India to the
USA were cut off. With the USA joining the war in 1941 the demand for raw materials multi-
plied without enough deposits, in this case for h.m., being mined.
For this reason in 1942, the Titanium Alloy Manufacturing Co., a subsidiary of National
Lead, decided to start mining h. m. in Florida. It focused its attention on a deposit east of Jack-
sonville, discovered by National Lead in the '30s, which at that time had also taken over the
Mineral City operations close nearby. National Lead and Titanium Alloy Manufacturing Co.
together founded the Rutile Mining Company of Florida, which in fall 1943 started mining the
dune players near Jacksonville, producing ilmenite and rutile for war purposes. Within a short
time, however, they encountered a number of serious difficulties in their process, caused by
their operation techniques applied, which endangered further production on the whole.








Help arrived with Humphreys Gold Corporation, founded in 1934, but looking back to a
much longer mining history (Thompson & Whittle, 1990). In 1943 this company had taken the
assignment to concentrate chromite from beach players in Oregon and for this purpose had
developed and later run the so-called Humphreys Spirals (Thompson & Welker, 1990).
After executing this commission a subsequent contract was made with the Rutile
Mining Company of Florida and in April 1944 responsibility for the h. m. mining operations
near Jacksonville was taken over. By the installation of Humphreys Spirals and technical
changes in the mining of the h. m. enriched sand, they succeeded in making the operations
profitable again. After the end of World War II, in 1946 zircon, and in 1949 monazite was first
produced from the Jacksonville deposits.

From a technical point of view the separation of h. m. was considerably eased by an
invention of J. Hall Carpenter, who, first as an employee of National Lead, later of Humphreys,
developed the "High-tension Separator" in 1946. In 1948 he founded Carpco, Inc., Jackson-
ville, which from that time on offered technical equipment to mining companies not only in
Florida.

Also with the end of World War II, the chemical company E. I. Du Pont de Nemours &
Company, Inc. started a large-scale exploration program on h. m. in Florida. In 1946, nearly at
the same time with the U.S. Bureau of Mines, the Trail Ridge deposit was discovered, for
which the necessary mining rights were acquired till the end of 1947. As the success of
Humphreys Gold Corporation's mining operations at Jacksonville had spread, Du Pont com-
missioned this company with the mining of their.h. m. from Trail Ridge too. After only starting
with ilmenite and rutile, zircon was being separated from 1950 and staurolite from 1952 for the
first time anywhere. In 1955 Humphreys opened the Highland plant north of the Trail Ridge
site, which led to a doubling of the tonnages produced.

Meanwhile the situation also had changed in central Florida. In 1948 the Riz Mineral
Company was sold and rearranged by its new owner, who changed its name to Florida Ore
Processing Company, Inc., implemented technical changes in the Palm Bay plant and started
production of a garnet concentrate. At the same time mining of dune players south of Vero
Beach was continued till 1954 (Calver, 1957).
In that year this deposit was depleted and mining shifted to west of Winter Beach. Here,
south of Wabasso and northwest of Vero Beach, an extremely low-grade (1.5 2 wt.-% h. m.)
dune placer had been discovered by the well-known George A. Pritchard before the end of
World War II, but not paid attention to any further for its low h. m. content (Mertie, 1975).
By order of Hobart Brothers Welding Company, the Florida Ore Processing Company
started mining this new deposit in 1954. In March 1955 the Florida Minerals Company, a
direct subsidiary of Hobart Brothers Welding Company took over the mining, while the h. m.
still were concentrated in the Palm Bay plant, till on Oct. 17, 1955 this plant caught fire. With
the complete destruction of their plant all activities of the Florida Ore Processing Company
ceased.
Hobart Brothers Company, however, decided not to stop mining at its just opened site,
but to erect a new plant close to its Winter Beach deposit. Here, from February 1956 to the
end of all h. m. mining in central Florida in 1963, small amounts of ilmenite, rutile, zircon,
monazite, and garnet were produced (Calver, 1957; Garnar, 1980).








While in the early `50s the Florida Ore Processing Company and Humphreys Gold Corpo-
ration for National Lead on one side and Du Pont on the other were already mining h. m.
players in Florida, the search for similar deposits all over the southeastern United States con-
tinued.
Du Pont discovered the h. m. players at Folkston and Yulee and did -exploration work on
the barrier islands of the Sea Island Chain (Gillson, 1959).
In 1955 National Lead acquired a large piece of land north of the Highland site of Trail
Ridge.

Along the southern Atlantic coast, Atlantic Engineering Corporation, Palm Beach
(Thoenen & Warne, 1949), was engaged in prospecting, while offshore northeastern Florida,
Freeman, Inc., founded by C. E. Freeman, Jacksonville, was interested in h. m. players (Rock
Products, 1954).
Heavy Minerals Company, a subsidiary of Crane Company, discovered h. m. players along
the Recent Gulf coast west of Panama City Beach, Florida, but decided instead to start mining
(1955 1959) fluvial monazite players in Horse Creek, South Carolina (details in Mertie, 1975,
p. 25).
Glidden Company in 1957 lost a lawsuit on mining h. m. players on Cumberland Island
(Fantel et al., 1986, E. V. Whittle, pers. comm., 1990) and, thereupon, preferred to mine tita-
nium minerals from players near Lakehurst, New Jersey (1964 1978).
Union Carbide and Carbon Corporation planned to mine h. m. on Amelia Island, while
Nuclear Magnetic Mining Company, St. Augustine, together with Chesapeake and Colorado
National Corporation had plans to mine h. m. from Anastasia State Park south of St. Augustine
and from players near Pensacola, Florida.
Humphreys Gold Corporation also played a major role in the exploration of several placer
deposits. Its major competitor at that time was the Bear Creek Mining Company, a subsidiary
of Kennecott Copper Corporation, which beginning in 1954, did systematical exploration work
above all in all counties of northeastern Florida (Mertie, 1958, 1975). An unpublished report of
the activities of this latter company in St. Johns County were found in the files of the Florida
Geological Survey in Tallahassee. Conclusions, drawn by rechecking raw data from 225 holes
drilled along public roads to depths of 10 meters in that county, were used in drawing fig. 27.

By the mid '50s numerous h. m. deposits had been discovered, of which a majority should
be mined. In fall 1957, however, the U.S. military surprisingly decided to cut down aircraft
construction in favor of rocket production (Garnar, 1980). As for military aircraft a large part
of the U.S. titanium production was used, a strong deterioration of ilmenite and rutile prices
was the immediate result. This price decline in turn led to a stop of nearly all mining plans and
to the withdrawal of the majority of companies prospecting in Florida.

An increase of zircon prices at nearly the same time, however, initiated Du Pont not to
renew the agreement with Humphreys Gold Corporation on the mining of the Trail Ridge
deposit, but to take over the production in 1958 itself.

In 1964 Humphreys Gold Corporation closed down its Jacksonville operations after more
than 20 years and shifted mining to the Folkston site in southeast Georgia, where production
was started in 1965 for Du Pont on a dune placer already discovered in 1952.

From 1966 to 1967 Carpco Engineering returned to the unreclaimed Jacksonville tailings
and for the first time in Florida produced a xenotime concentrate.







In 1972 American Cynamid Company, interested in titanium minerals, and Union Camp
Corporation, the property owner, founded a mining company called Titanium Enterprises with
the aim to mine h. m. players south of Green Cove Springs, which were discovered in 1966 by
Union Camp Corporation. Till 1978 ilmenite, rutile, zircon, and monazite was produced from
this second-largest placer deposit in Florida after Trail Ridge. In 1978, however, a decline of
zircon prices led to a stop of all operations and the complete Green Cove Springs deposit in-
cluding all equipment was offered for sale.





__


Deoslit
Mineral City

Melboune

Vero Beach


Winter Beach


Jacksonville


Mining

1916 1929

1939 1943


Operator

Buckman & Pritchard, Inc.


Products offered

II, Rt, Zr, Mo

II, Rt, Zr, Mo

II, Rt, Zr, Mo
II, Rt, Zr, Mo, Gr

II, Rt, Zr, Mo, Gr
II, Rt, Zr, Mo, Gr

II, Rt
II, Rt, Zr, Mo, Gr
Mo, Xe


Riz Mineral Co.


9' 1943 1948
1948 1954

1954 3' 1955
1955 1956

8' 1943 3 1944
4' 1944 12' 1964
1966 1967


Riz Mineral Co.
Florida Ore Processing Co.

Florida Ore Processing Co.
Florida Minerals Co.

Rutile Mining Co. of Florida
Humphrys Gold Corp.
Carpco Engineering (tailings)


Folkston

Boulogne

Trail Ridge


8' 1965 7' 1974 Humphreys Gold Corp.

I1' 1974 1l' 1979 Humphreys Mining Co.


Ti-Pr, Zr, Mo

Ti-Pr, Zr, Mo


4' 1949 1958
1958 -today


4' 1955 1958
1958 -today


1993 -today


1972 6' 1978
7' 1978 -4' 1980
4' 1980 1991
1992 -today


Humphreys Gold Corp.
E. I. Du Pont de Nemours
& Co., Inc.

Humphreys Gold Corp.
E. I. Du Pont de Nemours
& Co., Inc.

E. I. Du Pont de Nemours
& Co., Inc.


II, Res, St
II, Res, St


Highland



Marville


II, Res, Zr, St
II, Res, Zr, St


II, Res, Zr, St


Green Cove
Springs


Titanium Enterprises
Titanium Enterprises (tailings)
Associated Minerals (USA) Inc.
Renison Goldfields Cons. (USA)
Mineral Sands, Inc.


II, Rt, Zr, Mo
Zr, Mo, St
II, Rt, Lx, Zr, Mo, (St)
II, Rt, Lx, Zr, Mo


II = Ilmenite, Rt = Rutile, Lx = Leucoxene, Res = Residue, Ti-Pr = Titanium Product
Zr = Zircon, Mo = Monazite, Xe = Xenotime, St = Staurolite

first commercial production ofilmenite concentrate in Florida
first commercial production of zircon concentrate in Florida
first commercial production of rutile concentrate in Florida
first commercial production of monazite concentrate in Florida
first use of Humphreys Spirals in Florida
first use of high tension separators in Florida
first commercial production of garnet concentrate in Florida
first commercial production of staurolite concentrate in Florida
first commercial production ofxenotime concentrate in Florida


1916
1922
1925
1925
1944
1946
1948
1952
1966


Tab. 20: Important economic data of heavy mineral mining in Florida







One of the companies interested in taking over the operations was Humphreys Mining
Company, successor of Humphreys Gold Corporation. In 1975 after depletion of the Folkston
placer deposit this company had started mining the Boulogne placer nearby on its own
account. For 1980 it was planned to shift operations again, this time to the Altama players near
Brunswick, Georgia.
These plans, however, could not be realized for economic calculations and in 1980, after
closing down its Boulogne site, Humphreys had to go out of business. It was not before 1986
that Carpco, Inc. started production of Humphreys Spirals again, and in 1988 merged with
Humphreys Process Equipment, to in this way continue at least a part of the tradition of the
former many-membered and worldwide operating Humphreys companies.
For this reason a different owner for the Green Cove Springs operations had to be found.
In 1980 the experienced Associated Minerals Consolidated, a subsidiary of the Australian
mining company Consolidated Gold Fields Australia Ltd. (now Renison Goldfields Consoli-
dated Ltd.) took over. After the recovery of h. m. prices and successful exploration of a new
placer west of the main Green Cove Springs deposit, with the newly founded subsidiary Asso-
ciated Minerals (USA) Inc., a new name was soon established on the Florida h. m. market.

Presently, in the mid '90s, only two companies are active in Florida (see fig. 26). On the
one hand this is Du Pont, still mining the Trail Ridge deposit at its Trail Ridge and its new
Maxville sites, and on the other it is Renison Goldfields Consolidated (USA) Mineral Sands
Inc., renamed in 1992 from Associated Minerals (USA) Inc., mining its Green Cove Springs
ore body. Both companies are working together in a friendly way, as long as no new explora-
tion targets are concerned.
Partner in all questions of dressing techniques still is Carpco Inc. in Jacksonville which
since 1986 is also producing the well-established Humphreys Spirals again. Renison Goldfields
Consolidated (USA) has another supplier of technical equipment in its Australian mother com-
pany.
While in earlier years only few geologists were asked to state their opinions on questions
on economic geology problems, now all mining companies have their own geological sections,
which above all are engaged in exploration programs.

Plans of Du Pont to continue mining Trail Ridge even farther north at the Folkcston West
site (Pirkle et al., 1993) are proceeding, above all encountering problems due to increased
environmental restrictions (Okefenokee Swamp National Park nearby). RGC (USA) on the
other hand recently has decided to develop the Old Hickory placer deposit in Virginia
(Carpenter & Carpenter, 1991).

Finally coming to the question whether any of the other h. m. players in northeastern
Florida could be mined there is no clear picture. General requirements for h. m. placer deposits
in the southeastern United States, already published in 1950 by Cannon, who stated a minimum
grade of 4 5 wt.-% h. m. and a reserve of at least one million short tons of h. m. are still
valid. His relatively low minimum grade cited above is based on the use of Humphreys Spirals,
which for the first time enabled the concentration of h. m. from those low-grade deposits.
Nowadays even a cut-off grade of 2 wt.-% h. m. is acceptable, which allows the mining of
large scale deposits (see: Mertie, 1958, p. 23 and Lynd, 1983, p. 1340).
A closer look at the players already discovered in northeastern Florida, shows only minor
chances for the start of mining of any of these deposits. The very small deposit on Amelia Is-
land was covered by buildings and, therefore, will never be mined. A similar fate can be ex-
pected for the much larger Yulee deposit.








Subrecent h. m. players situated along the beaches of Florida will never be mined again, as
all barrier islands and beaches of the USA (outside Alaska) are either strongly covered with
buildings (Hilton Head Island, Ossabaw Island etc.) or are protected by their conversion into
recreation areas (Little Talbot Island, Cumberland Island).
In the placer district of Folkston-Boulogne several small players are known, which,
however, are not worth mining. Whether the Trail Ridge feature really contains feasible h. m.
concentrations in its northern part is only known by Du Pont. The economic problems in start-
ing the operations at their Maxville site, however, do not favor an opening of any other mining
site (e. g. Fokston West) within this century.

The only remaining deposit is the Jacksonville one, of which only a minor part was mined
between 1943 and 1964. Reserves of h. m. still in place can be calculated as about 10 million
tons. As in this area the covering with buildings is also increasing rapidly, most of these
reserves are not available any more. Totally unknown on the other hand is, whether this placer
district extends to the east below the swampy beach ridge plain between Jacksonville and Jack-
sonville Beach.
Above all west of Pablo Creek an increased radiation could be observed by aeroradiomet-
ric surveys (Grosz et al., 1989), which at any rate could be a sign for h. m. players (barrier is-
land of Princess Anne age ?) (see fig. 27).

In 1977, 25 km to the south, near the small town of Darien, St. Johns County, a well was
drilled by the Florida Geological Survey (Scott # 2 = core no.: W 13751) at a surface elevation
of 18.6 m above msl, with cores only taken at certain intervals (see fig. 27).
A this is the only one of thirteen wells, drilled outside of known placer deposits and con-
taining sands with more than 2 wt.-% h. m., results of analyses of samples of this core (after
Elsner, 1992 a) shall be cited below:

depth b. m. econ. min. Ep + Hb mean std. dev. skewness kurtosis
0 5 ft. 0.57 % 54 % 12 % 2.496 0.312 + 0.635 11.788
10 15 ft. not analyzed
15 20 ft. 2.40 % 71 % 1 % 2.580 0.303 + 0.028 7.849
20 25 ft. not analyzed
25 30 ft. 2.33 % 67 % 1 % 2.597 0.523 + 2.286 12.522
30 35 ft. not analyzed
35 40 ft. not analyzed
40 45 ft. not analyzed
45 50 ft. not analyzed
50 55 ft. 0.21 % 35 % 30 % 2.624 0.445 1.770 10.765

Tab. 21: Sediment parameters of sands of well Scott # 2. Surface: 18.6 m above ms1
(Ep = epidote, Hb = hornblende, all data in wt.-% or phi)

As only few samples of the core of well Scott # 2 were analyzed, neither the former
depositional environment, nor the thickness of the h. m. enriched sand is known precisely.
Comparisons with other players of northeastern Florida, however, favor a deposition of the
sands between 30 and 35 ft. in the nearshore zone. Sands between 15 and 20 ft. could have
been deposited in an eolian environment. Situated directly south of the Jacksonville deposit
these players could be of Sangamon age too.








The h. m. content of other regions of St. Johns County were checked by the Bear Creek
Mining Company back in the '50s (see above). Most of those samples gave h. m. percentages
of less than 0.5 wt.-%, only sands of the Pamlico age beach ridge plain west of St. Augustine
did contain h. m. with a maximum of 4.85 wt.-% .

If we summarize all the various statements given above, the whole area between Inter-
state 95 to the west and the Intracoastal Waterway to the east, and between St. Johns River to
the north and St. Augustine to the south seems to be of great promise. An extensive explora-
tion program including also the swampy areas of this region could most probably lead to the
discovery of new feasible deposits (see fig. 27).

At Doctor's Inlet Grosz et al. (1989) were able to show a radioactive anomaly, of which
no clear origin is known.
The extension of the Penholoway age shoreline north of Doctor's Inlet near Whitehouse
was already discovered by Thoenen & Warne (1949). According to J. M. Elder (RGC, pers.
comm., 1990) the placer deposits in this area, however, can not be mined due to a nearby air-
base and the dense population west of Jacksonville.

The discovery of new h. m. placer deposits in the future could be eased by geophysical
means, which have been developed a great deal further since the ages of McKelvey & Balsley
(1948). While these authors were mapping h. m. concentrations in the beach zone by using a
low-flying airplane, in other areas the application of (aero)radiometric surveys yielded much
better results (Moxham, 1954; Arnold, 1957; Grosz et al., 1989).
Apart from its high precision there are, however, some disadvantages to this method, as
only zircon and above all monazite by their radioactivity can be detected and as even a few
decimeters of h. ni. poor sands strongly hamper the discovery of placer deposits in sediments
below (Wynn & Grosz, 1983). The effect of interfering radiations of phosphates, both from
phosphorite deposits as well as from fertilizers, and from granite used in buildings, was dis-
cussed in detail by Grosz et al. (1989).
Tests of the U.S. Geological Survey to detect concentrations of ilmenite by induced po-
larization (IP) were described by Wynn & Grosz (1983) and Wynn et al. (1985). Tests of this
method were also run in the offshore zone (Wynn & Grosz, 1986) although till now no final
judgment about the practical uses of this method can be rendered.

After Force (1991, p. 80) all h. m. placer deposits in the southeastern United States, i. e.
all deposits ever mined in Florida and the Folkston deposit in SE-Georgia have yielded 5 Mt.
of TiO2 all tOgether. 14 Mt. of TiO2 still remain in the ground, of which at least some may be
worth producing in the future.








Geologic summary and economic conclusion


In northeastern Florida nine different h. m. placer deposits are known. All are to be
found parallel to the Recent or fossil shorelines, which means that their deposition was closely
linked to former sea level changes. For the first time information about' these local sea level
changes could be correlated with global events which ages, in turn, can be given relatively pre-
cisely by reviewing the international literature. By combining all formerly available information
and new findings the Cenozoic history of northeastern Florida can now be summarized as fol-
lows:

During the early and middle Tertiary Florida was a carbonate platform similar to the
Recent Bahamas platform. In late Miocene time the first noteworthy amounts of plastic sedi-
ments from the Appalachian mountains reached the Florida platform and by the mid-Pliocene
the deposition of carbonates was restricted to the southern tip of the Florida peninsula. In
northern and central Florida, coarse, poorly sorted plastic sediments (Cypresshead-Citronelle
Formation) were deposited by braided rivers. With rising sea level in middle late Pliocene time
the sea inundated major parts of this former river plain with its waves breaking against the
central parts of Florida, thereby finally forming the central Lakes Wales Ridge system.
Close to end of the Pliocene the sea level dropped again. Strong winds picked up the
sandy sediments of the former sea floor and huge dunal systems were formed, the largest
probably lying along the central axis of northern peninsular Florida. At the very end of the
Pliocene the sea level (Wicomico sea level) rose again, destroying all but the largest dune sys-
tem, the Trail Ridge feature, which now contains the largest h. m. placer deposit in the USA.

By the middle Pleistocene another glacial complex had initiated a new cycle of h. m. trans-
port and deposition, when with rising sea level at the very end of this glacial complex dunes
were formed along the advancing shoreline in northeastern Florida. Most of these coastal
dunes were destroyed by a sea level still rising, but a few remained as obstacles on the shallow
sea floor and by transverse bottom currents led to the deposition of h. m. in the nearshore
zone. In this way the placer deposits of Boulogne and Green Cove Springs (main ore body)
were formed. Coastal dunes of this Penholoway sea level make up the Folkston and Green
Cove Springs western ore bodies.

During the last interglacial (Pamlico sea level) several more placer deposits in northeastern
Florida were formed, most of their h. m. having been deposited in the eolian environment
(Yulee and Jacksonville deposits).
Eolian and beach storm placer deposits of Holocene aige can be found on Amelia and Little
Talbot Islands, as well as along the beaches between Jacksonville Beach and St. Augustine.

To allow direct economic comparisons between these various known h. m. placer
deposits of northeastern Florida, their most important economic parameters were summarized
in tab. 22. There, the rank of size of the placer deposits is easily recognizable. With original
reserves of nearly 52 million metric tonnes (Mt.) of available h. m. Trail Ridge is leading in
front of the Green Cove Springs deposit with only a third of its size. Only these two deposits
are currently being mined: Trail Ridge for nearly 50 years and Green Cove Springs for close to
25 years.
The original h. m. reserves of the Jacksonville deposit (mining between 1943 and 1964)
have not been much smaller than those of the Green Cove Springs deposit. Theoretical
reserves, still remaining in the Jacksonville area may be about 10 Mt. of h. m. This is more than







double the reserve of the Yulee deposit and more than eleven times the tonnage of h. m. in
place before the start of production near Boulogne, which was the smallest placer deposit ever
mined in Florida.

Also of great importance are the differences in the h. m. suite of the various deposits.
Both the monazite and rutile contents of the Trail Ridge placer are rather low, as well as the
monazite contents of the Yulee and Amelia Island deposits. The placer deposits on Little Tal-
bot Island remain those with the lowest percentage of economic minerals.

Characteristics of some selected especially big h. m. placer deposits from other regions of
the world are given in tab. 26. At first sight it is getting clear that the two largest h. m. deposits
in the world, WIM 150 and Richards Bay, contain about three times as many h. m. as Trail
Ridge. Besides, before being mined, Trail Ridge has been among the five biggest placer depos-
its in the world. The Green Cove Springs and Jacksonville deposits can both be ranked into the
"upper middle class". All the other players of northeastern Florida are only of local importance.









Selected bibliography

"The half of knowledge is to know where to fmnd knowledge"

Inscription Dodd Hall, Florida State University


AAPG = American Association of Petroleum Geologists
AIME = American Institute of Mining, Metallurgical and Petroleum Engineers
GSA = Geological Society of America
SEPM = Society of Economic Paleontologists and Mineralogists
SME = Society of Mining Engineers
GCAGS = Gulf Cost Association of Geological Societies

F.G.S. = Florida Geological Survey
G.G.S. = Georgia Geological Survey
U.S.B.M. = United States Bureau of Mines
U.S.G.S. = United States Geological Survey

JSP = Journal of Sedimentary Petrology
EMJ = Engineering and Mining Journal
PPP = Paleogeography, Paleoclimatology and Paleoecology


Arnold, C. F.
(1957) Magnetic and Radiometric Surveys of Titanium Beach Sand Deposits. Duval County, Florida.-
Company Report, Humphreys Gold Corporation: 5 pp.; unpublished.

Bailey, S. W.
(1956) (Cameron, E. N.; Spedden, H. R. & Weege, R. J.) The alteration of ilmenite in beach sands.-
Economic Geology, 51: pp. 263 279; New Haven, CT.

Baker, G.
(1962) Detrital Heavy Minerals in Natural Accumulates.- Australasian Institute of Mining and Metal-
lurgy, Monograph Series, 1: 146 pp; Melbourne.

Bartlett, P. M.
(1987) Republic of South Africa coastal and marine minerals potential.- Marine Mining, 6: pp. 359 -
383; London.

Baxter, J. L.
(1977) Heavy Mineral Sand Deposits of WVestern Australia.- Geological Survey of Western Australia,
Mineral Resources Bull., .10: 147 pp; Perth, WA.

Benbow, J.
(1990) Zircon markets. Heavy weather ahead.- Industrial Minerals, 278: pp. 27 37; London.

Bergmann, P. C.
(1983) Comparison ofsieving, settling and microscope determination ofsand grain size.- in: Tanner, W.
F. (ed.): Near-Shore Sedimentology.- Proceedings, 6th Symposium on Coastal Sedimentology:
pp. 35 -36; Tallahassee, FL.








Brooks, H. K.
(1960) Size frequency distribution of particles in sediments of the "Citronelle Formatiori".- in: Puri, H.
S. (ed.): Late Cenozoic Stratigraphy and Sedimentation of Central Florida.- Southeastern Geo-
logical Society, Guidebook 9th Field Trip: pp. 32 35; Tallahassee, FL.

Browning, J. S.
(1956) (Clenunons, B. H. & McVay, T. L.) Recovery of kyanite and sillimanite from Florida beach
sands.- U.S.B.M. Report of Investigation, 5274: 12 pp.; Washington, DC.

Bruyakin, Y. V.
(1989) Marine mining on the continental shelf Marine Mining, 8: pp. 391 403; New York, NY.

Burklew, R. H. Jr.
(1988) The Hydrogeologic System of Trail Ridge above the Basal Clays near Folkston, Georgia.- un-
published M.S. thesis, University of Florida: 191 pp.; Gainesville, FL.

Burns, V. M.
(1979) Marine placer minerals.- Reviews in Mineralogy, 6: pp. 347 380; Washington, DC.

Calver, J. L.
(1957) Mining andMineral Resources.- F.G.S., Bull., 9: 132 pp.; Tallahassee, FL.

Cannon, H. B.
(1950) Economic minerals in the beach sands of the southeastern United States.- in: Snyder, F. G. (ed.):
Proceedings of the Symposium on Mineral Resources of the Southeastern United States.-
University of Tennessee Press: pp. 202 210; Knoxvrille, TN.
(1957) Sand ilmenites of the eastern United States.- AIME, Mining Conference, October 1957, Preprint:
4 pp.; Tampa, FL.

Carpenter, J. H.
(1953) (Detweiler, J. C.; Gillson, J. L.; Weichel, E. C. & Wood, J. P.) Mining and concentration of
ilmenite and associated minerals at Trail Ridge, Fla.- Mining Engineering, 5: pp. 789 795;
New York, NY.
(1960) (& Griffith, R. H.): Production ofMonazite from Alluvial Concentrates.- Carpco Technical Bull.:
10 pp.; Jacksonville, FL.

Carpenter, R.H.
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... It is astonishing and incredible to us, but not to Nature; for she performs with utmost ease and simplicity
things which are even infinitely puzzling to our minds, and what is very difficult for us to comprehend is
quite easy for her to perform.


Galileo
Dialogue Concerning the Two World Systems (1630)

cited in: Komar (1976)





















































G.C.S.-W.O.B.
G.C.S.-W.M. Tail.
G.C.S.-W.M. Cc.
Hi.-W.M.Cc.

F.-W.M.Tail.
F.-W.M.Cc.


Original raw sand sample from the Green Cove Springs western ore body
Tailings of the Green Cove Springs wet mill,
Green Cove Springs wet mill concentrate,
Highland wet mill concentrate
Original raw sand sample from the Folkston ore body
Folkston wet mill tailings,
Folkston wet mill concentrate,


T6S-R23E-31Idbd
T5S-R23E-19baa
T4S-R22E-25cdb
T4S-R22E-12abd
T2S-R22E-15ddd
T4N-R23E-26dcb
T7S-R23E-21cac
T8S-R26E-10cdd
T7S-R26E-6cdd
T3N-R24E-32aa
T6S-R28E-8d
T5S-R28E-11cb
T6S-R28E-14bba
TIS-R27E-42
T4S-R24E-27ddd
T4S-R25E-13bac
T4S-R23E-16aad
T6S-R25E-7cd
T6S-R22E-24dc
T7S-R19E-lda
T7S-R2 1E-4cb
T5S-R2 1E-26cba


Appendices


Appendix 1: Origin of analyzed samples


a.) samples from well cores (see fig.
Florida Geological Survey, Tallahassee:


27 and tab. 24) stored in the core library of the


well number well name


county surface total depth


location


W 10488
W 10489
W 12360
W 12361
W 10473
W 10482
W 10481
W 12112
missing
W 13815
W 13744
W 13751
W 13765
W 14619
W 14219
W 14193
W 14179
W 13769
W 14283
W 14255
W 14280
W 13814


Trail Ridge 1
Trail Ridge 2
Highland 1
Highland 2
Trail Ridge 3
Boulogne 1
Union Camp 1
Union Camp 2
Union Camp 3
Cassidy 1
Scott 1
Scott 2
Scott 3
Carter 1
Jennings 1
Fox Meadows 1
Long Branch 1
Harris 1
Wainwright 1
Mizelle 1
Varnes 1
Raiford 1


Clay
Clay
Bradford
Baker
Baker
Nassau
Clay
Putnam
Clay
Nassau
St. Johns
St. Johns
St. Johns
Duval
Clay
Clay
Clay
Clay
Bradford
Bradford
Bradford
Bradford


72.8 m
62.8 m
61.6 m
58.2 m
50.9 m
30.8 m
34.1 m
25.9 m
36.0 m
24.4 m
8.5 m
18.6 m
7.6 m
3.7 m
27.4 m
15.2 m
26.2 m
29.6 m
55.2 m
40.5 m
42.7 m
39.0 m


- 28.3 m
18.4 m
88.7 m
19.5 m
36.9 m
2.6 m
1.2 m
8.2 m
4.0 m
- 125.0 m
- 68.3 m
- 85.6 m
- 66.1 m
- 148.7 m
- 122.5 m
- 93.6 m
- 71.3 m
- 67.7 m
- 30.8 m
2.1 m
10.8 m
43.9 m


Tab. 24: Key parameters of well cores of northeastern Florida


b.) samples from h.m. mining operations and others:





























phi mm ASTM mesh Tyler mesh

- 2.00 4.000 5 5
- 1.75 3.364 6 6
- 1.50 2.824 7 7
- 1.25 2.378 8 8
- 1.00 2.000 10 9
- 0.75 1.682 12 10
- 0.50 1.414 14 12
- 0.25 1.189 16 14
0.00 1.000 18 16
0.25 0.841 20 20
0.50 0.707 25 24
0.75 0.595 30 28
1.00 0.500 35 32
1.25 0.420 40 35
1.50 0.354 45 42
1.75 0.297 50 48
2.00 0.250 60 60
2.25 0.210 70 65
2.50 0.177 80 80
2.75 0.149 100 100
3.00 0.125 120 1'15
3.25 0.105 140 150
3.50 0.088 170 170
3.75 0.074 200 200
4.00 0.063 230 250
4.25 0.053 270 270
4.50 0.044 325 325


Appendix II: Characteristics of heavy mineral samples


ilmenite
leucoxene
rutile
zircon
monazite
xenotime


kyamite
staurolite
garnet
epidote
hornblende
beryl


spinel
topaz
sillimanite
andalusite
tourmaline
chloritoid


corundum
sphene
brookite
anatase
cassiterite
< 0.5 wt.-%


HM
Lx/l
mean
SD
Sk
K
T.F.
all: pan


heavy mineral content in weight-percent
ratio of leucoxene to ilmenite
arithmetic mean of the grain size distribution in phi
standard deviation of the grain size distribution (moment measures)
skewness of the grain size distribution (moment measures)
kurtosis of the grain size distribution (moment measures)
fine tail of the grain size distribution (2 4 phi) in weight-percent
5 phi


Tab. 25: Conversion table of sieve sizes


(x) mm = how many phi ?
(x) phi = how many mm ?


* log2 (x)= In(x)/In(2)
-+e '""(2.)on(D


-+phi looked for
mm looked for










In northeastern Florida ilmenite was or is being mined in the following sites: Ponte Ve-
dra Beach, Jacksonville, Trail Ridge, and Green Cove Springs. Titanium minerals of the Folk-
ston and Boulogne deposits were not separated, but sold as "Titanium Product" (a mixture of
ilmenite, leucoxene, and rutile). RGC sells a low-grade leucoxene mixture from its Green Cove
Springs deposits. By request of this company no results of any analyses of this product may be
published. Du Pont is producing the so-called "Residue", a mixture of leucoxene and rutile, for
its own pigment plants.
A number of analyses of these titanium mineral concentrates have been published in the
literature. Most of them are not very detailed, but may easily be compared with findings of this
work.

Trail Ridge:

TiOz e~ FeO Cr O, V20 L.O.I.
Gillson (1949) 64.0 % 26.0 % 4.1 %
Carpenter et al. (1953) ca. 63 %
Lynd et al. (1954) 64.1 % 25.6 % 4.7 % 0.07 % 0.12 % 1.0 %
Calver (1957) ca. 63 %
Lynd (1960a) 64.0 % 26.0 % 4.8 %
Giese et al. (1964) 63.0 66.8 %
Temple (1966) a 69.2 % 26.0 % 4.8 %
Tenfer & Temple (1966) 64.2 % 25.2 % 4.1 %
Peterson (1966) ca. 64 %
Garnar (1971) 64.5 %
Mackey (1972) 64.3 % 27.16 %
Garnar (1973) ca. 64 %
Mertie (1975) 61.5 % 26.40 % 4.61 %
Lynd & Lefond (1975) 64 % 28.48 % 1.33 % 0.007 % CaO, 0.20 % MgO,
0.12 % P20s, 0.10 % Nb20s,
Lynd & Lefond (1975) 0.28 % SiO2, 1.23 % Al203
(the same: Lynd, 1985)
Pirkle et al. (1984) ca. 64 %
Force & Garnar (1985) ca. 65 %
USBM (1985) ca. 66 %
Thompson & Whittle (1990) ca. 63 %
Lyn (1990) ca. 65 %

Tab. 26: Chemical composition of Trail Ridge ilmenite after various authors


Ti~ FeOFeO L.O.L
Gillson (1949) 82.1 % 9.0 % 1.6 % (also Lynd, 1960a)
Carpenter et al. (1953) ca. 80 % (also Calver, 1957;
Giese et al., 1964;
Peterson, 1966;
Garnar, 1971)
Tml(196 82.8 % 14.9 % 2.3 % 1.4 %


Imenite and leucoxene


Tab. 27: Chemical composition of Trail Ridge residue after various authors








Specific weights of Trail Ridge ilmenite and Trail Ridge residue were cited by Temple
(1966) as 4.09 g/cm3 and 3.77 g/cm respectively. Photos of various Trail Ridge ilmenite con-
centrates can be found in Temple (1966) and Garnar (1978 a, 1980).

Raw data of grain size analyses of Trail Ridge ilmenite concentrates were published by
Garnar (1980). This author stated the mean grain size of the ilmenite concentrate as 161 ym.
Mertie (1953), Lynd et al. (1954), and Temple (1966) pointed out that only a small part of
the ilmenite separated from the Trail Ridge placer is "fresh" ilmenite, defined by its stochiomet-
ric chemical composition (52.66 % TiO2, 47.34 % FeO, 0.00 % Fe203, after Mackey, 1966).

In the Trail Ridge ilmenite concentrate (I) Prof. Dr. J. F. W. Negendank (written comm.)
discovered mostly leucoxene, followed only in second rank by fresh, brown ilmenite, which at
its rim, however, was also already altered to leucoxene. In the Trail Ridge residue concentrate
(I) minerals found in rank of their frequency were: rutile ilmenite leucoxene hemoilmenite
(rare) pyrite flakes (rare) titanomagnetite (very rare).

Folkston:

The chemical composition of the "Titanium Product", produced from the Folkston
placer was given by the United States Bureau of Mines (1987) with ca. 71 % TiO2, by Lynd &
Lefond (1975, 1983) and Thompson & Whittle (1990) with ca. 72 % TiO2 and by Humphreys
Gold Corporation (1959) with 72.4 77.5 % TiO2. Temple (1966) published results of one
analysis with 76.1 % TiO2, 22.8 % Fe203, 1.0 % FeO, and 0.9 % L.O.I.. The specific weight
was said to have been 3.81 g/cm'.
Pirkle et al. (1984) published a TiO2-content of pure ilmenite of the Folkston placer of ca.,
62 %. For this work it was not possible to analyze any samples of the original "Titanium Prod-
uct", but only of lab concentrates of ilmenite, leucoxene, and rutile. After Prof. Dr. J. F. W.
Negendank (written comm.) in sample "I-F.-II." above all leucoxene and strongly weathered
ilmenite were found.

Findings of two grain size analyses of the original "Titanium Product" were found in un-
published notes of HGC. The following mean grain sizes could be calculated (n = 2) (for a
conversion table see tab. 25):

mesh wt-%
+ 48.........................................2 %
65........................................ .2 %
80........................................ .8 %
100......................................230 %
1 15........................................ .5 %
150......................................2 .7 %
170.....................................3268 %
200......................................3 .4 %
250......................................267 %
250......................................246 %

Based on these data the mean grain size of the "Titanium Product" can be given as
3.399 phi (94.8 Clm). Garnar (1980) published a mean grain size of the Folkston ilmenite of 97








Green Cove Springs:


After Garnar (1973) the average TiO2-COntent of the Green Cove Springs ilmenite was
63 %. In 1980 he published photos of an ilmenite concentrate produced by Titanium Enter-
prises. Pirkle et al. (1984) stated an average TiO2-COntent of this ilmenite of 64 %.

Prof. Dr. J. F. W. Negendank (written comm.) analyzed the I Green Cove Springs il-
menite concentrate, discovering in rank of frequency: leucoxene fresh, brown ilmenite with
leucoxene alteration rims fresh ilmenite.

RGC kindly offered the analysis of a bulk sample of ilmenite sent to Du Pont in early


1990:


TiO2
ZrO2
SiO2
Al203
Cr203


64.2 %
0.03 %
0.32 %
0.69 %
0.11 %


MnO
CaO
MgO
V20s
P20s


1.31 %
0.11 %
0.19 %
0.16 %
0.11 %


Boulogne:


Thompson & Whittle (1990) published a TiO2-content of the "Titanium Product" pro-
duced from the Boulogne placer of 72 %. Based on unpublished analyses (n = 2) of HMC the
chemical composition of this concentrate was 72.4 % TiO2, 20.25 % Fe203, and 2.04 % FeO.

The mean grain size after these analyses can be given with 3.320 phi (100. 1 pm).
Garnar (1980) published photos of Boulogne ilmenite and cited a mean grain size, as in
Folkston, of 97 Cpm.


Jacksonville:

Tiz FeO FeO CrgO z, PO L.O.I.
Gillson (1949) 60.3 % 26.3 % 5.6 % (also Lynd, 1960a)
Mertie (1953) 61.5 % 26.5 % 4.5 %
HGC (unpublished, n = 1) 59.3 % 24.46 % 10.37 %
HGC (unpublished, n = 1) 61.0 % 25.9 % 5.8 %
Du Pont (unpublished, n = 7) 60.1 % 22.3 % 10.8 % 0.07 % 0.13 % 0.33 %
Lynd (1960 a) 60.3 % 26.3 % 5.7 % 0.22 % 0.14 %
Giese et al. (1964) 60.4 %
Temple (1966) 66.3 % 24.2 % 9,5 % 1.7 %
Mackey (1972) 60.4 % 28.52 % 4.70 %
Mertie (1975) 64.0 % 25.0 % 4.5 %

Tab. 28: Chemical composition of Jacksonville ilmenite after various authors

According to unpublished notes of HGC the mean grain size of the ilmenite in 1961
was 3.249 phi (105.2 Cpm), and in 1962 3.312 phi (100.7 lum). The ilmenite concentrate pro-
duced in Jacksonville was sent to a pigment plant of the National Lead Company in St. Louis
and in this plant used for the manufacture of color pigments on a Ca-basis.









Another unpublished note is referring to an extensive chemical analysis of' Jacksonville
ilmenite in the first years of mining (January 13, 1945):


TiO2
SiO2
ZrO2
SnO2
Fe203
Al203
Cr203
Ni203
B203
V20s


60.63 %
1.0 %
0.60 %
0.001 %
25.76 %
2.0 %
0.25 %
0.05 %
0.05 %
0.05 %


FeO
CaO
MgO
MnO
BaO
CuO
PbO
Na20


6.62 %O/
0.50 %
1.2 %
1.4 %
0.01 %
0.001 %
traces
0.003 %


For this work ten of the ilmenite, leucoxene, and residue concentrates produced in
northeastern Florida could be analyzed. On the next pages the results of nine (without Green
Cove Springs leucoxene) of these geochemical (tab. 29) and mineralogical/granulometric
analyses (tab. 30) are compiled.

Geochemistry: All data were established by using X-ray fluorescence analysis at the
German Geological Survey in Hannover with partial rechecking by several measurements. All
data in weight-percent or parts per million (ppm), respectively. Percentages of SO3 and As are
minimum figures.

Mineralogy: All data in weight-percent. A list of mineral abbreviations used can be
found at the beginning of this chapter.

Granulometry: All data in weight-percent. For comparison reasons the sieve sizes were
given in ASTM-mesh. A conversion table in phi and mm is given in table 25.


=sample taken in 1990
=sample 1
= variety A

= Trail Ridge
= Folkston

= "Ilmenite"
= "Residue"
= "Staurolite"
= "Biasill"
= "Garnet"
= "Zircon"
= "Premium-grade Zircon"
= "Zirclean"


sample taken in 1991
sample 2
variety B


I
1
A

T.R.
F.

II.
Res.
St.
Bia.
Gr.
Zr.
PZr.
Zrc.


G.C.S. = Green Cove Springs
J. = Jacksonville


Lx.
Rt.
CSt.
Stb.
Kya.
SZr.
ZrT.
Zro.


"Leucoxene"
"Rutile"
"Coarse Staurolite"
" Starblast"
"IKyasill"l
"Standard-grade Zircon"
"Zircon T"
"'Zircore"l










I-T.R. II-T. R. I-G.C.S. I-J.-1 1-J.-2 1-F. il-F. I-T.R. II-T.R.
11. 11. II. II. II. II. LxY. Res. Res.
TiO2 64.89 64.30 63.67 62.70 62.95 59.78 81.23 80.89 79.37
SiOz 0.05 0.40 0.19 0.06 0.10 0.84 1.00 0.31 1.18
Zr/HfO2 0.04 0.25 0.05 0.14 0.13 0.21 1.33 0.87 1.11
Al203 1.48 1.81 1.43 1.36 1.32 1.82 2.42 1.51 1.65
Fe203 28.27 28.10 28.94 30.24 30.44 31.77 9.18 11.69 12.97
MnO 1.02 1.02 1.19 1.36 1.38 1.48 0.47 0.39 0.43
MgO0.31 0.30 0.30 0.30 0.27 0.34 0.20 0.20 0.18
CaO 0.07 0.08 0.17 0.12 0.06 0.36 0.21 0.08 0.08
Na20 0.07 0.08 <0.05 <0.05 <0.05 <0.05 0.07 0.15 0.13
K20 <0.01 <0.01 0.01 <0.01 0.01 0.01 0.01 0.01 <0.01
P20s 0.17 0.14 0.19 0.18 0.16 0.34 1.12 0.20 0.22
V20s 0.14 0.15 0.14 0.14 0.14 0.13 0.18 0.19 0.20
Cr203 0.06 0.06 0.09 0.09 0.09 0.11 0.13 0.09 0.10
(SO3) <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
L.O.I. 2.67 2.77 2.56 2.22 2.09 1.59 1.08 1.87 2.00
(As) 12 <7 11 21 10 27 28 29 27
Bi <10 <10 <10 <10 <10 <10 <10 <10 <10
Co 44 32 47 70 54 61 10 30 13
Cs 94 97 85 100 94 91 142 124 Ill
Cu n.a. 157 123 n.a. Ill n.a. 158 n.a. 122
Ga 114 78 139 81 82 62 88 105 80
Hf <18 57 <18 <18 <18 <18 217 193 217
Mo 4 16 18 5 <4 <4 30 47 51
Nb 684 674 688 748 740 769 1327 2303 1827
Ni 8 <7 <7 <7 <7 <7 47 <7 <7
Pb 219 188 224 228 140 129 257 188 201
Rb 15 11 18 9 15 21 14 16 11
Sc 56 52 49 46 45 52 40 52 55
Sn 35 46 24 30 29 33 74 894 404
Sr 61 55 26 14 25 72 33 40 70
Ta 81 69 78 61 92 63 107 242 192
Th 53 17 114 102 71 215 1345 57 53
U <5 5 <5 <5 <5 32 193 10 23
W <10 29 <10 <10 27 19 132 222 136
Y <5 17 22 11 <5 78 1077 18 24
Zn 232 225 213 253 241 304 182 128 107
Zr 302 1809 380 1050 950 1505 9631 6303 8079

In some samples impurities of grains of monazite, zircon, garnet, or epidote (see Baker, 1962,
p. I17), or cassiterite (see Grosz, 1987, p. 343), or staurolite, or other Al-silicates (see tab. 44) were
found.


Tab. 29: Geochemical composition of ilmenite and leucoxene concentrates produced in north-
eastern Florida.









I-T. R. II-T.R. I-G.C.S. iI-.-1 1-J.-2 I-F. I-. I-T.R. II-T. L
II. II. 11. II. II. 11. Lx. Res. Res.
II 81.0 98.2 78.2 87.2 74.5 83.0 78.8 23.3 83.3
Lx 18.8 0.3 21.3 9.3 23.3 13.4 2.2. 24.4 2.8
Rt 1.0 0.1 2.7 1.5 1.3 15.3 50.0 10.4
Zr 0.2 0.2 0.3 0.2 1.8 1.1 1.9
KY <0.1 <0.1 0.2
St 0.1 <0.1 0.1 0.1 0.1 0.1 0.1 1.1
Gr 0.1 0.4
Ep<0.1 0.2 1.0 0.2
Si 0.2 0.1
Tm 0.2
MolXe 0.1 0.1 0.5 0.1 0.6 1.2
To <0.1
Se <0.1
At 0.i 0.4 0.2
Br <0.1
Cs <0.1 0.3 0.2
Quartz0.2 <0.1 0.1 <0.1 <0.1 <0.1 <0.1

mesh
+ 25 0.004
30 0.007 0.004 0.015 0.006 0.003 0.004 0.004
35 0.005 0.016 0.021 0.003 0.006 0.005 0.002 0.006 0.005
40 0.005 0.070 0.034 0.007 0.006 0.005 0.003 0.011 0.011
45 0.013 0.211 0.031 0.014 0.005 0.008 0.006 0.014 0.019
50 0.194 1.249 0.011 0.020 0.016 0.025 0.010 0.134 0.116
60 2.396 2.755 0.031 0.058 0.051 0.075 0.013 1.929 1.618
70 11.349 8.184 0.176 0.254 0.247 0.286 0.007 6.169 7.166
80 16.884 11.768 0.774 0.787 0.833 0.834 0.010 9.761 10.736
100 19.859 18.932 2.250 1.981 1.891 1.932 0.032 13.713 16.197
120 27.797 25.094 16.100 10.395 9.321 8.433 1.500 23.862 20.393
140 13.405 21.800 38.726 33.102 28.272 25.857 11.262 17.779 20.609
170 5.223 7.089 34.490 36.857 40.378 42.204 32.679 11.869 10.498
200 1.634 1.691 6.296 13.898 16.077 17.146 38.082 6.359 5.180
230 0.578 0.470 0.838 2.445 2.672 2.974 14.577 3.726 3.301
270 0.065 0.204 0.089 0.079 0.080 0.101 1.303 2.502 2.107
325 0.268 0.094 0.023 0.049 0.057 0.052 0.436 0.788 0.840
325 0.310 0.360 0.090 0.040 0.080 0.040 0.070 1.370 1.200

mean (p)152.1 145.8 109.6 104.3 102.5 101.6 87.1 126.4 129.5
mean (h)2.717 2.778 3.190 3.261 3.286 3.299 3.521 2.984 2.949
SD 0.423 0.447 0.262 0.277 0.280 0.282 0.254 0.557 0.545
Sk 0.631 0.088 -0.581 -0.513 -0.504 -0.773 -0.058 0.694 0.753
K 5.479 5.089 10.231 6.146 6.352 6.960 5.259 4.380 4.512



Tab. 30: Mineralogical and granulometric composition of ilmenite and leucoxene concentrates
produced in northeastern Florida








Rutile


Rutile was or is being produced in northeastern Florida from the Ponte Vedra Beach,
Jacksonville, and Green Cove Spring deposits. Rutile, which can be found in the Folkston,
Boulogne and Trail Ridge players, however, was and is not separated, but .sold in form of high-
grade titanium products.

Jacksonville:

The following analyses of samples of rutile of the Jacksonville placer can be cited after
several mostly unpublished reports:

TAM4CO HGC HGC Du Pont Lynd
(n = 1) (n =- 1) (n = 1) (n = 8)
(5-16-1i944) (5-15-1962) ( 1 -15-1962) ( 1960 a)
TiO2 92.80 % 94.8 % 95.4 % 96.2 % 94.2 %
SiO2 1.5 % 1.04 %
ZrO2 1.2 % 1.00 %
Fe203 2.00 % 1.35 % 1.62 % 1.29 % 1.71 %
FeO 0.0 % 1.02 % 0.32 %
Al203 1.3 % 0.047 %
Cr203 0.06 % 0.16 % 0.09 % 0.10 %
MgO0.10 % 0.10 %
MnO 0.02 % 0.03 %
CaO 0.17 % 0.10 %
Na20 0.01%
P20s 0.08 % 0.0 % 0.16 %
V20s 0.30 % 0.37 % 0.28 % 0.27 %
B203 0.02 %
BaO traces
CuO 0.001 %
Nb20s 0.005 %
Ni203 0.002 %
PbO traces
SnO2 0.07 %
Ta203 0.005 %

Tab. 3 1: Chemical composition of Jacksonville rutile after various authors

The mean grain size of the rutile concentrate produced at Jacksonville was 3.255 phi
(104.7 Cpm) in 1952 and 3.304 phi (101.3 pm) in 1962, respectively, after unpublished notes of
HGC.

Green Cove Springs:

According to one analysis of a bulk of rutile delivered to Kemira Oy Inc. at the end of
1989, which was kindly placed at the author's disposal by RGC, the chemical composition of
this rutile was 94.6 % TiO2, 3.06 % Fe203, 0.41 % Al203, and 0.36 % SiO2.








For this investigation two of the rutile concentrates commercially produced in NE-
Florida were at hand for analyses. Another rutile concentrate was produced in the lab using
Folkston placer sands.
Explanations to data given in tab. 32 and 33 can be found on the previous pages.

I-G.C.S.-Rt. II-F.-Rt. I-J.-Rt.
TiO2 92.85 % ()95.09 % 94.65 %
SiO2 0.09 % 0.31% 0.11%
Zr/HfO2 0.11 % 0.73 % 0.37 %
Al203 0.62 % 0.81 % 0.43 %
Fe203 3.28 % 1.06 % 1.95 %
MnO 0.15 % 0.05 % 0.09 %
MgO 0.14 % 0.15 % 0.14 %
CaO 0.10 % 0.08 % 0.06 %
Na20 0.13 % 0.09 % <0.05 %
K20 0.01 % 0.02 % 0.01 %
P20J 0.16 % 0.10 % 0.08 %
V20s 0.22 % 0.27 % 0.27 %
Cr203 0.10 % 0.10 % 0.10 %
(SO3) <0.05 % <0.05 % <0.05 %
L.O.I. 1.39 % 0.36 % 0.81 %
(As) 30 pm22 pm16pm
Bi <10 pm<10 pm Co 19 pm<7 pm16pm
Cs 131 pm138 pm137pm
Cu n.a. 67 pmn.a.
Ga 123 p 25 pm55pm
Hf 60 pm110 pm59pm
Mo 57 pm37 pm10pm
Nb 2623 pm2955 pm3853pm
Ni <7 pm<7 pm<7pm
Pb 144 pm81 pmn.a.
Rb 12 pm<5 pm7pm
Sc 39 pm36 pm40pm
Sn 166 pm179 pm205pm
Sr 18 pm26 pm9pm
Ta 258 pm267 pm.350pm
Th 26 pm76 pm15pm
U <5 pm31 pm<5pm
W 225 pm258 pm338pm
Y <5 pm119 pm<5pm
Zn 198 pm14 pm78pm
Zr 760 pm5333 pm2706 m


High contents of SiO2 and Zr
(compare with Baker, 1962, p. 120).


can be explained by impurities by grains of zircon


Tab. 32: Geochemical composition of rutile concentrates produced in northeastern Florida









I-G.C.S.-Rt. II-F.-Rt. I-J.-Rt.
II 6.5 % 20. 1 % 3.4 %
Lx 46.6 % 0.7 % 16.0 %
Rt 46.7 % 74.9 % 77.2 %
Zr 0.9 % 0.4 %
Gr 0.2 %
MolXe 0.2 %
Se 0. 1%
At 3.1 % 2.8 %
Br 0.2 %


mesh
+ 25 0.002 %
30 0.001 % 0.003 %
35 0.001 % 0.002 %
40 0.005 % 0.003 % 0.004 %
45 0.001 % 0.004 % 0.004 %
50 0.001 % 0.008 % 0.013 %
60 0.013 % 0.025 % 0.098 %
70 0.124 % 0.263 % 0.623 %
80 0.668 % 0.903 % 1.749 %
100 2.769 % 2.005 % 3.606 %
120 13.705 % 5.047 % 14.225 %
140 33.204 % 21.236 % 32.858 %
170 35.336 % 33.653 % 32.750 %
200 12.277 % 26.655 % 12.088 %
230 1.586 % 9.254 % 1.809 %
270 0.076 % 0.671 % 0.069 %
325 0.107 % 0.020 % 0.036 %
325 0.120 % 0.060 % 0.050 %

mean 106.1 pm95.5 pm108.2 p
mean 3.236 pi3.389 ph 3.208ph
SD 0.277 0.314 0.306
Sk 0.029 -0.511 -0.554
K 5.592 4.802 5.236


Tab. 33: Mineralogical and granulometric composition of
northeastern Florida


rutile concentrates produced in








Zi rcon


Zircon was or rather is being produced from all placer deposits in NE-Florida. Several
information on these zircon concentrates is available from the literature and from unpublished
reports:

ZrO, + HfO, TiO2 Fe2031
minimum % maximum %/ maximum %/I
Standard 65.0 0.25 0.15
Intermediate 65.5 -66.0 0.06 0.10
Premium 66.0 0.10 0.05
'USA
Du Pont Standard 65.0 0.35 0.05
Du Pont Premium 65.0 66.0 0.15 0.05
RGC (G.C.S.) 66.5
HGC (Jacksonville) 65.0 0.35 0.05
HGC (Folkston) 65.0 0.25 0.10
Australia
RZ Mines Premium 66.5 0.05 0.10
Allied Eneabba 65.5 0.15 0.10
South Afrwa
R. Bay Minerals Standard 65.0 0.30 0.30
R. Bay Minerals Prime 65.0 0.18 0.10
.Brasil
Nuclemon Standard 64.5 0.50 0.30
Nuclemon Premium 65.5 0.10 0.05
India, Malaysia, Sri Lanka
Indian Rare Earths Ltd. 65.0 0.30 0.08
Malaysia Mining Corp. 65.5 0.30 0.10
CelnMineral Sands Corp. 65.0 0.50 0.20

Tab. 34: Typical specifications of commercial zircon concentrates, after Coope (1987), Clarke
(1987), and an unpublished note of HGC.



Green Cove Springs:

The zircon from the Green Cove Springs deposit is prismatic and much less rounded
than the one from Trail Ridge (Garnar, 1978 b). Garnar (1980, 1983) stated a mean grain size
of 98 Cpm, and in 1985 of 100 pm, respectively. In 1980 he published a photo of the zircon
concentrate as sold by Titanium Enterprises.
The zircon currently sold by RGC is too fine to be used as foundry sand or in the manufac-
ture of refractory bricks. For this reason it is ground to zircon flour and put to use in the ce-
ramics industry.







AMU kindly offered results of two zircon analyses for publication. These stem from a
delivery of a bulk of zircon to the Z Tech Corporation, New Hampshire, at the end of 1989
and from the sample "II-G.C.S.-Zr." (see below) (AMU- #: 8941 9017):

Z -Tech II-G.C.S.-Zr.
(Zr+Hf)O2 66.66 % 66. 19 %
HfO2 1.28 %
SiO2 32.52 % 32.30 %
TiO2 0.08 % 0.07 %
Al203 0.36 % 0.39 %
Fe203 0.046 % 0.040 %
SiO2 (free) 0.06 % 0.04 %
L.O.D. ( @ 105 OC) <0.01 % 0.00 %
L.O.I. ( @ 1000 OC) 0.02 % 0.02 %
'mean grain size 3.390 hi (95.4 m)3.390 pi (95.4 m

Trail Ridge:

Zircon found in the Trail Ridge deposit is very uniform, regarding its size (relatively
coarse), its morphology (well rounded), and its purity (see below). Coatings are nearly absent.
Many grains are frosted by the eolian transport (Garnar, 1978 a, 1983, 1985). Garnar (1980)
showed photos of these zircon grains and cited a mean grain size of the concentrate of 122 pm.
Another grain size analysis (120 pLm) can be found in Garnar (1983, 1985).
In the early '90s Du Pont was producing five different zircon concentrates from its Trail
Ridge placer deposit. These were a premium-grade zircon and a standard-grade zircon for
applications in the foundry, refractory and ceramics industry (Garnar, 1985, 1990; Clarke,
1987). The so-called Zirclean was used as a special abrasive, while Zircore, a mixture of zir-
con, kyanite, sillimanite, and corundum, was sold as foundry sand (Garnar, 1978 b, 1983,
1985, 1990; Clarke, 1987). This Zircore was a substitute for Kyasill (T. E. Garnar, 1972,
1980, pers comm., 1991), which was developed upon first investigations by Browning et al.
(1956). Also not on the market anymore is Zircon M, a mixture of zircon and some magnetic
minerals (Garnar, 1983).
During a worldwide shortage of zircon at the end of the '60s Du Pont developed the Zir-
con T, which is a zircon concentrate compounded with up to two percent of titanium minerals.
This Zircon T is still distributed as a special foundry sand (Clarke, 1987).

Folkston:

Thompson & Whittle (1990) cited a (Zr+Hf)O2 COntent of the Folkston zircon concen-
trate of ca. 66 %. After seven unpublished reports of chemical analyses of HGC the chemical
composition of the zircon can be stated as follows:
mean standard deviation
(Zr+Hf)O2 65.9 % 0.366 %
TiO2 0.11 % 0.022 %
Fe203 0.031 % 0.005 %
Al203 0.44 % 0.092 %
P20s 0.091 % 0.035 %
SiO2 (free) 0.062 % 0.035 %








After three unpublished notes to grain size analyses the mean grain size of the zircon con-
centrate was 3.690 phi (77.5 Cpm).

Boulogne:

Only little is known from the zircon concentrate, which was separated from the Bou-
logne placer sands. After data of five unpublished grain size analyses the mean grain size was
3.635 phi (80.5 Cpm). This is exactly the mean grain size (81 Cpm) published by Garnar in 1980.
In this publication he also showed a photo of this zircon concentrate.


Jacksonville:

After unpublished notes of analyses for HGC on zircon produced from the Jacksonville
deposit the following findings can be cited:

TAMCO Ledoux & Co~mpany, Inc.
(1-17-1945) (1-31-1945
(Zr+Hf)O2 66.33 % 66.94 %
SiO2 32.14 % 31.34 %
TiO2 0.217 % 0.28 %
Fe203 0.140 % 0.09 %
Al203 0.23 % 0.60 %
MgO 0.05 %
CaO 0.12 %
Na20 0.01%
P20s 0.25 %
CeOl 0.12 %
La2Oz 0.05 %
Cr2Oz 0.002 %
Ni20, 0.005 %
CuO 0.002 %
PbO, MnO, SOV20s traces

The mean grain size of the zircon concentrate in 1952 was 3.472 phi (90. 1 Cpm), and in
1962 3.483 phi (89.4 Cpm), respectively.


For this work nearly all zircon concentrates produced in NE-Florida were available for
analyses. On the next pages, findings of these geochemical, mineralogical, and granulometric
analyses are compiled.









I-G.C.S. II-G.C.S. I-F. 11 -F. I-T.R. TI-T.R II-T R. Il-T.R II-T.R. IT-T.R
Zr. Zr. Zr. Zr. SZr. SZr. Zr. Zr. Zre. Zro.
Zr/HfO2 64.74 ? 66.26 65.45 65.88 65.43 65.21 66.75 66.03 59.58 45.67
HfO2 1.24 1.26 1.25 1.28 1.23 1.21 1.25 1.23 1.08 0.77
SiO2 32.40 32.37 32.32 32.38 32.27 32.30 32.17 32.60 31.00 35.00
TiO2 0.17 0.06 0.18 0.35 0.14 0.18 0.13 1.00 3.22 1.42
Al203 0.49 0.42 0.43 0.26 0.80 1.88 0.96 0.70 5.00 17.00
Fe203 0.10 0.05 0.09 0.04 0.07 0.07 0.06 0.11 0.98 0.55
MnO 0.03 0.04 0.03 0.04 0.03 0.04 0.04 0.04 0.06 0.04
MgO 0.11 <0.10 0.09 0.10 0.16 0.28 <0.10 <0.10 <0.10 <0.10
CaO 0.04 0.04 0.05 0.03 0.03 0.02 0.03 0.03 0.04 0.03
Na20 0.07 <0.10 0.07 <0.10 0.09 <0.10 <0.10 <0.10 <0.10 0.19
Kz0 0.03 0.01 0.03 0.01 0.03 0.02 0.01 0.01 0.01 0.01
P20s 0. 11 0.12 0.12 0.15 0.11 0.10 0.12 0.12 0.17 0.06
(SO3) 0.16 0.17 0.09 0.05 0.13 0.10 0.11 0.09 0.08 < 0.05
L.O.I. 0.10 0.90 0.48 1.10 0.50 1.77 1.40 1.27 2.23 1.53
(A) <7 <7 <7 <7 <7 <7 <7 <7 <7 <7
Ba 196 184 171 174 155 183 199 129 169 68
Bi <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
Ce <35 <35 <35 <35 <35 <35 <35 <35 <35 <35
Co n.a. <7 n.a. <7 n.a. <7 <7 <7 <7 <7
Cr <7 <7 <7 <7 <7 <7 <7 <7 30 96
Cu n.a. 133 n.a. 172 n.a. 149 160 178 209 136
Ga 11 <5 7 <5 <5 <5 <5 <5 <5 11
Mo <4 <4 <4 <4 <4 <4 <4 <4 <4 <4
Nb <5 <5 <5 <5 <5 <5 <5 <5 44 <5
Ni <7 <7 <7 <7 <7 <7 <7 <7 <7 <7
Pb 30 37 44 33 59 48 37 44 43 44
Rb <5 <5 <5 <5 <5 <5 <5 <5 <5 <5
Sn 36 <50 89 <50 103 <50 <50 <50 <50 <50
Sr <5 <5 <5 <5 <5 <5 <5 <5 <5 <5
Ta <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
Th 138 184 148 229 193 200 174 200 290 129
U 200 210 203 220 231 227 247 254 234 159
V 12 19 12 <10 24 <10 <10 27 49 87
W n.a. 117 n.a. 142 n.a. 126 112 125 120 104
if 605 288 743 381 801 379 360 367 453 421
Zn 154 36 83 49 143 116 84 362 1592' 245



In some samples impurities of grains of various titanium minerals (see Baker, 1962, p. I 17),
gahnite, or Al-silicates (see tab. 44) were found.


Tab. 35: Geochemical composition of zircon concentrates produced in northeastern Florida









I-G.C.S. If -G.C.S. I-F. 11 -F. I-T. R. H-T.R. 11-T.R. HI-T.R. Il-T R. T-T.R
Zr. Zr. Zr. Zr. SZr. SZr. Zr. ZrT. Zrc. Zro.
II <0.1 0.4 1.6 0.6
Lx 0.2 0.2 0.4 0.6
Rt 0.2 -0.3 0.8 0.1 0. 1 0.4 2. 1 0.2
Zr 99.3 99.2 97.6 99.2 98.9 97.7 98.2 98.3 86.2 65.6
Ky 0.3 0.2 0.1 0.3 1.1 1.5 0.3 1.5 10.9
St 0.2 0.2 0.4 0.1 0.1 0.5 7.2 3.5
Gr <0.1 0.3
Ep 0.1
Si 0.6 0.1 <0.1 0.2 0.1 6.0
An 0.1 0.9
Tm 0.1 1.3
Mo/Xe 0.2
To 0.1 0.1 1.2
Sp 0.4
Co 0.4 0.3 0.1 0.3 4.4
Se 0.3
At 0.3
Br 0.2
Quartz0.4 <0.1 <0.1 <0.1 <0.1 4.5
mesh
+ 20 ().004
25 0.002 0.010
30 0.001 0.000 0.024
35 0.001 0.003 0.002 0.004 0.052
40 0.001 0.001 0.002 0.002 0.002 0.001 0.005 0.025 0.I90
45 0.003 0.002 0.003 0.001 0.002 0.006 0.004 0.013 0.070 0.683
50 0.005 0.003 0.006 0.002 0.009 0.052 0.009 0.138 0.337 2.296
60 0.007 0.005 0.006 0.007 0.012 0.570 0.129 0.910 1.235 4.307
70 0.013 0.005 0.016 0.011 0.046 2.861 1.051 3.843 4.196 9.819
80 0.059 0.012 0.253 0.024 0.540 6.066 3.359 7.168 6.188 11.850
100 0.453 0.025 1.115 0.113 2.843 10.663 8.778 11.913 10.292 13.771
120 5.136 2.396 3.768 0.484 18.879 21.503 21.286 23.916 19.486 17.521
140 21.364 23.158 11.379 3.101 36.025 35.295 40.040 34.466 32.208 23.115
170 40.412 42.163 36.417 19.636 29.685 18.313 20.505 14.535 18.620 12.834
200 24.988 24.684 32.168 45.971 9.421 4.160 4.332 2.651 6.063 3.140
230 6.521 6.468 13.376 22.819 1.847 0.351 0.340 0.227 0.955 0.240
270 0.461 0.542 1.061 5 .543 0.291 0.052 0.047 0.070 0.099 0.027
325 0.337 0.192 0.362 2.158 0.171 0.014 0.016 0.017 0.051 0.009
325 0.230 0.110 0.060 0.120 0.220 0.080 0.010 0.120 0.160 0.100

mean (p) 94.9 94.5 89.9 79.3 108.7 124.4 119.2 129.0 124.8 146.6
mean (h)3.397 3 .404 3.476 3.657 3.202 3 .007 3.068 2.954 3.002 2.770
SD 0.271 0.247 0.284 0.258 0.287 0.356 0.305 0.366 0.412 0.508
Sk 0.455 0.432 -0.362 0.212 0.595 -0.492 -0.309 -0.440 -0.502 -0.466
K 6.120 5.507 4.684 5.536 6.793 4.175 5.176 4.483 4.380 3.170

Tab. 36: Mineralogical and granulometric composition of zircon concentrates produced in
northeastern Florida








Monazite and xenotime


The average content of ThO2 and U30s in monazites (n = 53) of the southeastern
United States was found by Mertie (1975) to be 5.67 %, and 0.38 %, respectively.
Monazite concentrates were separated from all placer deposits in northeastern Florida ex-
cept Trail Ridge. Xenotime was only separated from tailings of the Jacksonville deposit (see
chapter on Jacksonville).

Boulogne:

Photos of a monazite concentrate produced from the Boulogne sands were shown by
Garnar (1980), who quoted a mean grain size of this concentrate of 69 Cpm. After unpublished
reports of two grain size analyses this mean grain size could be calculated as only 3.916 phi
(66.2 Cpm).

Jacksonville:

Nothing is known about the chemical composition of either the monazite or the xeno-
time concentrate produced at Jacksonville. After Carpenter & Griffith (1960) the mean grain
size of the monazite concentrate was about 3.73 phi (75 Cpm), after unpublished reports of
Humphreys (1962) it could be calculated as 3.795 phi (72.0 Cpm), after Mertie (1975) it was
about 3.61 phi (82 Cpm) in the northern ore body.

Folkston:

After unpublished reports of serial analyses of HGC (1970) and of the chemical com-
pany W.R. Grace & Co. a number of details are known about the monazite concentrate pro-
duced from the Folkston deposit. The average chemical composition (n = 74) of this concen-
trate can be quoted as follows:

Mean Standard Deviation

REO 58.9 % 0.96 %
ThO2 4.2 % 0.60 %
H2SO4 -inSoluble 8.1 % 1.49 %
(i.e. zircon, staurolite, quartz, ilmenite, rutile)
SiO2 2.6 % 0.49 %
TiO2 0.43 % 0.339 %
ZrO2 3.7 % 1.17 %
Fe203 0.63 % 0.201 %
Al203 1.7 % 0.47 %
CaO 1.1 % 0.20 %
MnO 0.107 % 0.0832 %
PbO 0.16 % 0.05 %

The composition of the REO is given in tab. 37. Attention is called in this table to the
high content of heavy RE, which must be explained by mixing monazite with xenotime (E. V.
Whittle, pers. comm., 1990).

After unpublished results of three grain size analyses the mean grain size of the monazite
concentrate was 3.970 phi (63.8 Clm).