Fluorspar Deposits 

of Utah

GEOLOGICAL SURVEY BULLETIN 1005

Fluorspar Deposits 

of Utah

By W. R. THURSTON, M. H. STAATZ, D. C. COX, and others

GEOLOGICAL SURVEY BULLETIN 1005

/. F. Smith, Jr., 7. R. JFilmarth, A, H. 

PFadsworth, Jr., and H. L. Bauer, Jr.,

assisted in the writing of this report. 

Prepared in cooperation with the State of 

Utah through the University of Utah. 

This report concerns work done partly on 

behalf of the U. S. Atomic Energy 

Commission and is published with the 

permission of the Commission.

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1954
v>, 1005

UNITED STATES DEPARTMENT OF THE INTERIOR 

Douglas McKay, Secretary

GEOLOGICAL SURVEY 

W. E. Wrather, Director

For sale by the Superintendent of Documents, U. S. Government Printing Office 

Washington 25, D. C.
CONTENTS

Page

Introduction, by W. R. Thurston.. ________ ___________ ' 1

History of fluorspar mining in Utah __ --__-_________--_____--___ 3

Classification of the deposits. ______ ____ __ __________ 4

Mineralogy of the deposits_____________________________-________ 4

Deposits in Indian Peak Range and Monarch claims, Beaver County,

by W. R. Thurston. __ ____ _______ _____ _. _______ 6

Indian Peak Range____________________-___________--__________ 6

General geology--_--------___-__--- -_______-_--________ 6

Description of deposits_---_______-------_-_-_-----------___ 8

Cougar Spar mine__________________________--_.___-____ 8

Blue Bell mine...-- ____ _____ - __ __ _ ___________ 10

Noonday prospect_------____--____---____--_-_________ 12

JB prospect _ ________________________________________ 13

Utah mine____--____________-______________-__________ 14

Lost Sheep and Dugout claims. _----__-_-_--------______ 16

Monarch (Staats) claims-____-___-_____________-__--___________ 16

Deposits in Star district, Beaver County, by D. C. Cox_ _______________ 19

Description of deposits.--------------------------------------.- 21

Brown Thrush claim__-___________. ________________________ 21

Cabin claim __ ___________________________________________ 21

Fluorine Ledge and Lucky Boy No. 2 claims__-__---__________ 22

Hub, Lady Bryan, Monte Cristo, Moscow, and Wild Bill mines

and Manassa claim______-_______________________________ 22

Quartzite claim __ ________________________________________ 23

Virginia and North Virginia Extension claims _____---__.______ 23

Deposits in Thomas Range district, Juab County, by M. H. Staatz, V. R.

Wilmarth, andH. L. Bauer, Jr.. ___________________________________ 24

General geology ________-_____-__-___---_-_-___-___-_-_________ 26

Suggestions for prospecting. ____________________________________ 28

Description of deposits. _ _______________________________________ 29

Bell Hill property __-___--____-__----__-._______-__________ 29

Blowout property __ _ _ -_-_____-_--______-________-_____.__ 30

Dell Nos. 1, 2, and 3 claims __ ---_-----____.______-_._.____ 32

Dell No. 5 property __ _________.________ __________________ 33

Eagle Rock property.. _ _____________'_______________________ 33

Floride (Original Spor) mine______------ -_---___----___._____ 34

Fluorine (Fluerin) Queen property_-----_____-___- ___________ 37

Fluorine Queen No. 4 claim_______. _________________________ 38

Harrisite property. _----------_--------__-____---__._______ 38

Lost Sheep property. __-____-_-._---______-__--_--__.-_____ 40

Lucky Louie property..-. ___________________ _______________ 42

Nonella No. 1 claim_____-____-_----____-______-___. _______ 42

Oversight No. 4 property___-_^__------_________-.__________ 43

Thursday No. 3 property.. _______--_-_-_--_-___---.________ 43

Silver Queen deposit, Tooele County, by J. F. Smith, Jr., and A. H. Wadsworth, Jr _--_-----_-----_---------------------------------_--_-- 45

Resources and possible development, by W. R. Thurston_______________ 48

Literature cited ___________________________________________________ 52

Index __---_-_-_------------------_----------------_-----------_-- 53

m
IV CONTENTS

ILLUSTRATIONS

' ' [Plates 1-6, 8 in pocket]

1 ...... ....... Page

PLATE 1. Geologic map of the Cougar Spar-Blue Bell area, Beaver County,

' Utah. . ..,. <-.

2. Geologic plans and section, of the Cougar Spar mine.

: 3. Geologic map and section of the Blue Bell mine.

4. Geologic map, plan, and section of-.JB prospect.

;. 5. Map and. sections of the Bell Hill property.

6. Geologic map, plans, and section of accessible underground 

	workings, Floride property.

7. Fluorspar pipes____-_--_-_____________-_-__--_-______ Facing 28

8. Map and section of the Harrisite property.

FIGURE 1. Index map of fluorspar deposits in Utah-__________________ 1

2. Fluorspar production chart______________________..____-___ 3

3. Index map of fluorspar deposits in Beaver County._________ 7

4. Claim map of Cougar Spar mine________________________ 9

5. Plat of Blue Bell claims_______________________ 11

6. Map of Noonday prospect.-_______________--___-__---__- 13

7. Map of Utah mine_-___-----_------------------_-------- 15

8. Map of geology adjacent to main shaft, Staats mine._______ 18

9. Map of winze, Staats mine__-___--_----i----_---__------- 19

f 10. Index map of Star district---.-----------.--------------- 20

11. Index map of Thomas Range district__--__-_-_-_--_-----_- 25

12. Map of Blowout property.---------------.--------------- 31

13. Map of Eagle Rock property-___--___-____-_--_____---__- 35

14. Map of fluorspar pipes, Fluorine Queen property_________ 37

15. Map of Fluorine Queen No. 4 fluorspar pipe __.__---_-_ 39

16. Map of fluorspar pipes, Lost Sheep property _______________ 41

r 17. Map and section of Thursday property-___________________ 44

, 18. Map of Silver Queen area______________________________ 47

TABLES

TABLE 1. Fluorspar localities in tHe Star- district, BeaverXoUnty, Utah-. 21 

2, Fluorspar produced in the Thomas Range district, Juab County,

J. Utah, through September 1950--------------.- -------- 26

,... 3. Minor occurrences of fluorite in Utah,______________________ 50
FLUORSPAR DEPOSITS OF UTAH

By W. B. THURSTON, M. H. STAATZ, D. C. Cox, and others.

j ... . ABSTRACT ;

The studies of fluorspar localities in Utah made by the U. ,S. Geological Survey during and since the recent war are summarized. The fluorspar, at the 

Cougar Spar and Blue Bell mines, in the Indian Peak Range of .western Beaver 

County occurs as fissure veins in fault and breccia zones in volcanic and intrusive rocks. At the Monarch (Staats) claims in west-central Beaver County 

fluorspar was mined chiefly from a fault between limestone and rhyolite 

porphyry. The Thomas Range district in Juab County has yielded : sizeable 

tonnages of fluorspar from pipes in faulted dolomite and rhyolite porphyry. 

From 1918 to 1924 the Silver Queen mine in Tooele County produced fluorspar 

from fissure veins in faulted limestone, ,

; The report describes the geology |of producing mines and the various prospects 

examined. . Production and reserves of fluorspar for Utah are summarized.

i INTRODUCTION

I ByW.B.Thurston

i Fluorspar has been reported from many parts of Utah (fig. l)y 

and in recent years the State's production has become increasingly^ 

important. The annual fluorspar production (fig. 2) increased from'' 

an average of less than 500 tons for the period from 1935 through 

1943 to about 9,500 tons in 1948, 8,300 tons in 1949, and 18,900 tons 

in 1950. This trend toward expanding production can be expected 

to continue.

i Production of commercial quantities has been limited to Beaver, 

^Tuab, and Tooele Counties. In Beaver County fluorspar has been 

mined in the Star district near Milford, in the Monarch (Staats) area 

47 miles west of Milford, and in the Indian Peak Bange near the 

Utah-Nevada State line. In Juab County the fluorspar area is in the 

Thomas Bange in, the center of the county, about 48 miles east of the 

Utah-Nevada State, line. The fluorspar mined in Tooele County 

came from the Silver Queen (Wildcat) mine near Clive. Although 

the tonnage of ore mined from these three areas has not formed a large, 

part of the national production (fig. 2), it did contribute materially 

to the fluorspar needed during the recent war. Minor occurrences 

of fluorite are listed in table 3. ; 

The known reserves .of fluorspar in Utah total about 450,000 tons 

of material having a minimum of 40 percent of CaF2 . Further

1
FLUORSPAR DEPOSITS OF UTAH

|"BOX~ELDER """" """

EXPLANATION

Lesser fluorspar deposits

Minor fluorite occurrences

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FIGURE 1. Index map of Utah showing .distribution of fluorspar deposits.

geologic Study and prospecting are needed, however, before the 

potentialities of most of the fluorspar deposits of Utah are knOWH.

This report Summarizes the Studies of fluorspar in Utah that were 

made as a part of the recent wartime program for the investigation 

6f strategic and critical minerals. The work consisted of detailed

geologic mapping of individual deposits to obtain information on

the occurrence and distribution Of minable fluorspar and to aid 

in exploring and developing fluorspar during World War II. 

Between August 1945 and July 1946, the investigations were
INTRODUCTION

Compiled from Mineral Resources In the United 

States, 1910-31, and Minerals Yearbook, 1932-50

FIGURE 2.; Fluorspar production of Utah compared to national fluorspar production.

made in cooperation with the State of Utah through the University 

of Utah. The study of the Thomas Range district in 1950, however, 

was part of an investigation of uranium resources being carried out 

by the U. S. Geological Survey on behalf of the Atomic Energy 

Commission.

Most of the field work that this report is based upon was done by 

the writers, assisted at various times by J. O. Fisher, Elliot Gillerman, 

D. M. Henderson, and E. D. Washburn. The work was under three, 

supervisors: L. R. Page, R. E. Van Alstine. and J. S. Williams.

HISTORY OF FLUORSPAR MINING IN UTAH

The first recorded mining of fluorspar in Utah was at the Silver 

Queen mine near Clive, Tooele County; some 20 tons was sold in 

1918. In the period 1918-1924 about 900 tons of saleable fluorspar 

was produced from the Silver Queen mine. In the next decade no 

fluorspar was mined in the State. In 1935 production was reported 

from the Monarch and Indian Peak areas in Beaver County, and 

between 1935 and 1945 Beaver County was the largest producer 'of 

fluorspar in Utah. In May 1943 fluorspar was first produced from 

claims located in the Thomas Range in Juab County, and by September 1950 some 35,700 tons had been produced from that district. The 

production data are summarized in figure 2.
4. FLUORSPAR DEPOSITS OF UTAH

CLASSIFICATION OF THE DEPOSITS

Most of the fluorspar deposits of Utah are epithermal deposits filling fault fissures and interstices in fault breccia. At many of the 

deposits fault movement was recurrent during:the period of mineralization, and locally the fluorite is brecciated. Some of the deposits in 

the Thomas Range district of Juab County and in the Star district 

of Beaver County are replacement deposits; the irregular boundaries 

of fragments of limestone and rhyolite porphyry enclosed in massive 

fluorspar suggest partial replacement at the Monarch (Staats) deposits of Beaver County. Evidences of wall-rock alteration generally 

have not been observed in the fluorspar districts of Utah.

MINERALOGY OF THE DEPOSITS

.Fluorite. In most of the Utah deposits the fluorite is massive; 

.however, well-formed crystals, generally cubes, have been observed 

in Beaver County in deposits of the Indian Peak Range, Monarch 

(Staats) claims, and Star district, and in Tooele County at the Silver 

Queen and Silver King deposits. The grain size ranges from very 

coarse, as in the deposits of the Indian Peak Range, to extremely fine 

as in the Monarch (Staats) deposit and in the Thomas Range district, 

Juab County. Much of the Thomas Range fluorite is soft and 

powdery.

The fluorite ranges from colorless to green, blue, and dark purple 

in the Beaver County deposits, from white to purple in the Juab 

County deposits, and from almost colorless to blue and green in the 

Silver Queen deposit, Too.ele County. At the Monarch (Staats) deposit some of the dark-purple massive fluorite, when freshly broken, 

releases a gas that may be free fluorine.1

Silica minerals. Quartz occurs as fissure fillings, crusts, and selvages on rock fragments in the deposits of the Indian Peak Range and 

fills holes and cracks in brecciated fluorite. Most of the quartz is massive and milky.white to clear. Prismatic arid finely granular varieties 

are common, however, and in many localities form crusts around 

breccia fragments. An intergrowth of lamellar quartz and calcite 

with orthoclase was found at the JB mine. Chalcedony locally was 

formed after the fluorite and quartz were deposited in veins of the 

Indian Peak Range.

Quartz locally fills openings in fluorite and the dolomite wall rock

in the Thomas Range district; in some deposits the silica minerals and 

fluorite form a fine boxwork structure. A streak of reddish opaline 

material is along the margin of one of the veins at the Silver Queen 

property, Tooele County.

1 Determination by Michael Fleischer, U. S. Geological Survey.
INTRODUCTION 5

Carbonate minerals. Lamellar intergrowths of white calcite and 

quartz were observed in the Indian Peak Range; most of the calcite 

is the white massive type, however, and formed later than the fluorite. 

A dark-brown fibrous calcite is also associated with fluorite in these 

deposits. In the Thomas Range district dolomite commonly occurs 

in the matrix of the granular fluorite, but the carbonate minerals 

generally make up less than 5 percent of the ore. White coarsely 

crystalline aragonite forms veins in the dolomite next to some of the 

fluorspar deposits in this district.

Other carbonate minerals associated with fluorite in some of the 

Utah deposits are witherite and rhodochrosite. Crystals of dolomite 

and white witherite have been found at the Silver Queen property. 

At the Moscow mine in the Star district rhodochrosite occurs with the 

fluorite.

Uranium, minerals. The fluorspar deposits in the Thomas Range 

district are abnormally radioactive, but generally no uranium minerals 

can be seen. Carnojite is present in the fluorspar at the Eagle Rock 

property, the Floride property, and in the West pipe at the Fluorine 

Queen property. At the Bell Hill and Harrisite properties it is also 

visible on the dolomite wall rock but not in the fluorspar. In the 

Monarch (Staats) deposit of Beaver County, Wyant 2 found autunite 

and uranophane Ideally as coatings on the fluorite.

Other minerals. Clay minerals constitute a variable, but generally 

the largest, part of the gangue in the Thomas Range and Monarch 

'( Staats) fluorspar deposits. Orthoclase, probably in the form of 

adularia,8 makes up about 10 percent of an intergrowth of lamellar 

quartz and calcite in a specimen from the JB mine in the Indian Peak 

Range. At various places within a 90-acre tract surrounding the 

Silver Queen property, barite, pyrite, chalcopyrite, and traces of gold 

and silver have been reported (Burchard, 1933, p. 21) in veins with 

fluorite.

Sulfide minerals are associated with fluorite elsewhere in Utah. 

Pyrite occurs in the wall rock of the fluorspar veins at the Monarch 

(Staats) property. In the contact-metamorphic deposits of the 

Star district galena, sphalerite, pyrite, and chalcopyrite accompany 

fluorite, rhodochrosite, magnetite, specularite, and various silicates 

(sericite, muscovite, garnet, epidote, tremolite, diopside, and pyroxene) . " A few other minerals are found in the minor occurrences of 

fluorite listed in table 3.

2 Wyant, D. G., 1947, Staats fluorspar mine, Beaver County, Utah: U. S. Geol. Survey, 

unpublished rept, 11 p.

3 Determination by Jewell J. Glass, U. S. Geological Survey.
6 FLUORSPAR DEPOSITS OF UTAH

DEPOSITS IN INDIAN PEAK RANGE AND MONARCH 

'CLAIMS,. BEAVER COUNTY

. ' By W. R. Thurston.

INDIAN PEAK RANGE 

GENERAL, GEOLOGY

The main producing area of Beaver CoUnty is in the Indian Peak 

Range (fig. 3) partly in the old Washington metal-mining district 

but mainly northeast of it. The main fluorspar producing properties 

are the Cougar Spar and Blue Bell mines in T. 30 S., R. 18 W., and 

the "Utah mine and JB claim in T. 30 S., R. 17 W. Scattered exposures 

of fluorite-bearing material are found over an area of about 20 square 

miles.

The fluorspar deposits are in an area of volcanic flows and tuffs 

that have been intruded by a quartz diorite stock. One small area of 

quartzite was noted, but no other sedimentary rocks were found. The 

flows range in composition from rhyolite to andesite. Microscopic 

examination of the extrusive rocks in the Cougar Spar-Blue Bell areas 

(pi. 1) shows that the majority are latites. These latite flows have 

dacitic, andesitic, and trachytic facies, show considerable alteration, 

and contain many inclusions. The inclusions have the same range 

in composition as the flows and represent both preexisting material 

picked up by the moving lava and chilled parts broken off the main 

flow. In some localities flows are separated by lenses of pyroclastic 

material. Many perlitic bands separate the rhyolite flows. The tuffs 

are cemented volcanic ash containing abundant quartz grains. They 

are extensively devitrified, and in some exposures are difficult to distinguish from the rhyolite.

The intrusive rock is a quartz diorite that contains a small amount 

of orthoclase. The quartz diorite is epidotized near the fault zone at 

the Cougar Spar mine. Discontinuous vertical rhyolite dikes, striking in a northeasterly direction and ranging in width from 4 to 20 

feet, Occur in the quartz diorite. The rhyolite is generally fine grained 

and banded parallel to the walls.

A small dacite flow, near latite in composition, rests on eroded 

quartz diorite on the ridge southwest of the Cougar Spar mine. Most 

Of the igneOUS rOCks Of Western Utah and eastern Nevada generally

are regarded as being of Tertiary age, but this dacite flow may be of 

Quaternary age.

The rocks of the area are broken by fault and shear zones. Hydrothermal solutions, probably of the epithermal type, altered the country 

rock and deposited quartz, calcite, and fluprite in the. zones of dislocation. The mineralized zones are as wide as 250 feet but do not have 

well-defined walls; the veins are biggest and most common near the
FIGDRB 3. Index map showing fluorspar localities in Bea
8 FLUORSPAR DEPOSITS OF UTAH

center of these zones and grade outward through progressively less 

brecciated and less mineralized rock to almost unaltered country rock. 

Movement along the faults was recurrent throughout mineralization, 

and deposition did not proceed uniformly, as indicated by many sharp 

structural truncations and mineral repetitions in the veins. The 

vein minerals are locally crushed, and the veins contain many vugs 

and openings. The fluorspar occurs most abundantly in the highly 

deformed parts of the fault zones, although small amounts of fluorite 

are present with other vein minerals throughout the breccia. The 

fluorspar bodies vary from lenses and veins of almost pure fluorite to 

coarsely crystalline aggregates of quartz, calcite, and fluorite containing rock fragments. Individual veins and lenses of fluorspar pinch 

and swell within short distances and lose identity by grading laterally 

and vertically into other vein material.

The general order of mineralization, as revealed in mine workings, 

appears to have been: fine-grained quartz, white lamellar calcite, 

granular quartz, prismatic quartz, fluorite, massive quartz, chalcedony, massive white calcite, and dark-brown calcite.

DESCRIPTION OF INDIVIDUAL DEPOSITS

: ; COUGAR SPAR MINE

Tjie Cougar Spar mine is on the east side of the Indian Peak Range 

in £Ey4 sec. 10, T. 30 S., R. 18 W., at an average altitude of 7,800 

feet (fig. 3). The mine may be reached by graded roads from either 

Milford in Beaver County, a distance of 57 miles, or from Lund in 

If on County, a distance of 35 miles. Lund is the nearest shipping 

point on the Union Pacific Railroad.

W. C. Dalton and S. M. Dalton of Parowan, Utah, staked a claim 

at the Cougar Spar deposit in 1937 and sank the inclined shaft of the 

upper workings. In 1941 Hubert C. Eyre of Minersville, Utah, relocated the claim and staked an additional claim on each side: the 

three claims were named the Spar, Spar 1, and Spar 2. E. A. McKenzie of Minersville and Fred Morrman and B. M, Anderson of Los 

Angeles leased the claims from Eyre in 1941 and 1942 and shipped 

about 600 tons of fluorspar. In the fall of 1942 the Tintic Standard

Mi»inff Co. of Salt Lake City acquired the property from Eyre. The 

three claims were Surveyed for patent, three additional claime were* 

located, and two 40-acre parcels of ground adjoining the claims were 

acquired (fig. 4). In the fall of 1943, the U. S. Bureau of Mines

explored the property by trenching, sampling, and drifting (Marsh

and Everett, 1945; Everett and Wilson, 1951), and the Tintic Standard

Mining Co. built a 150-ton-a-day jig mill and started operations,

The following Geological Survey men have worked on the geology 

of the Cougar Spar area: D. C. Cox and J. O. Fisher mapped the
DEPOSITS IN INDIAN RANGE AND MONARCH CLAIMS

FIQDKH 4. Map showing claims and surface plant, Cougar Spar mine, Beaver County,

Utah.

trenches and other workings of the Bureau of Mines in April and 

June 1943; A. E. Granger continued this work until July 1944; from 

July 1944 through December 1945 the writer recorded the developments at the Cougar Spar mine. From August through December 

1945 the topography and geology of the area (pi. 1) were mapped 

by the writer, assisted part of the time by D. M. Henderson and part 

of the time by Elliot Gillerman. Contacts are poorly exposed, and 

most of the mapping had to be done on the basis of float distribution. 

Mapping was further hampered by snow.

The fluorspar deposit at the Cougar Spar mine is in a fault zone 

near the contact between an intruded quartz diorite and rock of a volcanic series (pi. 1). The fault zone strikes N. 15° W. and is traceable 

for at least a mile both north and south of the mine. South of the 

mine the quartz diorite is in fault contact with various members, 

chiefly pyroclastic, of the volcanic series; north of the mine for 2,000 

feet it is in contact with extrusive rocks. Farther north the fault zone 

continues within various latitic pyroclastic rocks and flows. The
O ' FLUORSPAR DEPOSITS OF UTAH

^urface trace indicates that the fault zone has a steep but variable dip 

tjo the east. The trace is marked by a belt of quartz veins and quartzfilled breccia; in places lamellar calcite may be found, but detritajl 

$uorite is rare. At thexCougar Spar mine the surface of ; the fault 

;zone was marked by an especially broad belt of overburden containing 

vein quartz and quartz-filled breccia. A ledge of quartz-cemented 

breccia from 2 to 4 feet wide rises as much as 5 feet above the ground 

for a distance of 200 feet along the westiside of the fault zone. Detrital fluorspar is not common even above the known deposit ; so, the possibility of additional fluorspar bodies north and south of the workings 

cannot be eliminated because of the scarcity of fluorspar float.

The Cougar Spar deposit was first explored by an inclined shaft, 

surface trenches, several crosscuts, and adits at the 40- and 100-foot 

levels (pi. 2 and fig. 4). These workings yielded about 600 tons of 

fluorspar. The Tintic Standard Mining Co. developed the mine 

\vith an adit at the 200-foot level, which leads directly to the jig mill 

'(pi. 2 and fig. 4). An adit at the 300-foot level was started late in 

JL945. The workings on the, 200-foot level consist of an adit 700 feet 

long, and almost 900 feet of drifts and crosscuts (pi. 2). The workings extend about 500 feet along the strike of the fault zone. 

1 In the mine a fault zone more than 200 feet wide on the 200-foot 

level strikes about N. 30° W. and dips steeply east. A white tuff forming the north wall at the west end of the mine is silicified and sliced 

into several blocks by small branch faults (pi. 2) . The blocks of tuff 

near the quartz diorite on the southwest are altered to a gray soft rock. 

The fault zone appears to contain more fragments and blocks of the 

quartz diorite than of the tuff; however, the finer portions of the 

gouge may have been derived from the tuff, because the tuff shows a

greater tendency to alter and weather to a soft material than does 

the quartz diorite. The fissures and breccia were filled with quartz, 

calcite, and fluorite. Postfluoritization movement did not make any 

major changes in the fault as a whole but truncated the fissure fillings

in many places, offsetting tHe fluorspar-bearing zones from 5 to 30

feet. The offsets are greater and more distinct near the surface than

they are at depth.

BLUE BELL MINE

The Blue Bell mine is in SE% sec. 4, T. 30 S., R. 18 W., about 6,000 

feet northwest of the Cougar Spar mine and at an altitude of 8,500 

feet (pi. Land fig. 3) . The Blue Bell property includes 24 unpatented

claims (fig. .5) , which were located in the spring of 193Y by H. J. Holt 

of Milf ord, Utah. Holt was the operator and part owner of the Blue 

Bell mine. .
DEPOSITS IN 'INDIAN RANGE AND MONARCH CLAIMS 11

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FIGURE 5. Plat of Blue Bell claims, Beaver County, Utah.
12 . FLUORSPAR DEPOSITS OF UTAH

In April 1943, D. C. Cox and J. O. Fisher visited the Blue Bell property as part of the Geological Survey's program for the investigation 

of strategic minerals. In August 1944 the writer, assisted by E. D. 

Washburn, mapped the topography and geology in the immediate 

vicinity of the mine workings.

The workings on the property consist of 2 shafts, several pits and 

trenches, a series of bulldozer cuts, and 1 adit (pi. 3). The main shaft 

is vertical and 50 feet deep; at the bottom of the shaft are 40 feet of 

irregular drifts. This shaft was not in use because of the inflow of 

water. The other shaft is inclined 65° NW. for 30 feet; a 100-foot 

drift extends northward from it. On the surface near the shafts an 

area 180 feet long and roughly 30 feet wide was levelled and partly 

stripped by a bulldozer. All of the surface and underground work 

has been done in an area about 330 feet long and 30 feet wide, in search 

of minable widths of high-grade ore. In the workings the relations 

of the fluorite to the other vein minerals are not well exposed. The 

quartz, calcite, and fluorite occur as vertical lenses striking N. 35° W. 

in a shear zone in greenish-gray porphyritic latite. Most of the 

workings have been driven along the fluorspar-rich parts of the shear 

zone.

Deeper workings were driven by the U. S. Bureau of Mines. A 

460-foot adit cut the fluorspar-bearing zone 400 feet from the portal 

and at a vertical depth of 140 feet below the collar of the main shaft 

(pi. 3), and drifts were driven from this adit. At this depth the 

fluorspar-bearing zone is 12 feet wide and forms part of a sheared 

and mineralized zone 40 feet wide. Only small stringers of fluorspar 

were found in the workings at this level, and appear to be fewer and 

narrower than those near the surface. The east side of the fault zone 

is vertical where exposed in the adit and was not cut elsewhere. The 

west side was cut in the adit and in the south drift and crosscut. The 

steep opposed dips recorded and the relation of surface and underground exposures indicate that the shear zone is essentially vertical 

despite the varied attitudes of the internal and marginal structures.

NOONDAY PROSPECT

The Noonday prospect, owned by H. A. McKenzie of MinersviiiCj 

Utah, and leased by Tintic Standard Mining Co., is about halfway

between tlie Blue Bell and Cougar Spar mines (pi. 1). A shallow

trench and a 30-foot inclined shaft expose a 2-fOflt Vein of QURFtZ Rlld 

fiuorite in a shear zone in green latite. At the bottom of the shaft

the vein is narrower and leaner than in the trench (fig, 6), The

Veil! Strikes N. 10°-"YV. and dips 45° W. It was not possible to locate

this fluorspar vein either north or south of the prospect workings, 

and similar veins were not found nearby.
DEPOSITS IN INDIAN RANGE AND MONARCH CLAIMS 13

t »*+**+, 

*++* + + \

\ *^ ^r + + -4 * * *

 v \T + + + _^r- +

100 Feet

Vertical scale of section same as horizontal 

EXPLANATION

ZZB LInclined shaft Fault showing dip; dashed 

where approximately located

Fluorspar-bearing 

quartz vein

Geology by W. R. f hurston, December 1945

FIGURE 6. Sketch map of Noonday prospect, Beaver County, Utah. 

JB PROSPECT

The JB prospect is in sec. 30, T. 30 S., K. 17 W., about 3y2 miles 

southeast of the Cougar Spar mine (fig. 3). The prospect may be 

reached by an unimproved road near the Cougar Spar property or 

by a branch of the main access road to the Cougar Spar mine.

The JB claim was located in July 1942 by Bart W. Mortensen, John 

Davenport, Gene Bullock, and Vera Mortensen, all of Parowan, Utah. 

It has been leased for an indefinite term by Theo. E. Stevens of Milford, Utah. Surface trenching by the lessee between July 1942 and 

June 1943 yielded about 30 tons of high-grade fluorspar. In June 

1943, D. C. Cox and J. 0. Fisher mapped the trenches on the JB 

claim and traced the vein-zone from them to the Utah mine. The 

Bureau of Mines started underground exploration at the JB prospect

286657 54 2
14 FLUORSPAR DEPOSITS OF UTAH

in October 1943 (Everett and Wilson, 1950). A. E. Granger of the 

Geological Survey made frequent.visits to the ^FB vprospect while the 

Bureau of Mines was doing the exploratory work. In July 1944 the 

writer, assisted by E. D. Washburn, mapped" the topography and 

geology of the JB ar.ea and made detailed geologic maps of the surface atiid underground workings (pi. 4). The writer kept these maps 

up to date iuntit the Bureau of Mines completed the exploratory work 

in October 1944, .: ... :

The workings 'at. the JB. prospect consist of several trenches over 

an area about 250 feet lorig.and 200 feet wide; the underground workings consist of a 106-foot shaft, inclined 48° SB., with about 550 feet 

of drifts and cro'sscuts 'at a' vertical depth of 63 feet below the collar 

of the shaft and from 70 to: 110 feet below the trenched area.

The JB prospect is in a broad fault zone between a red dacite on 

the northwest and a green andesite on the southeast. The fault zone 

consists of a fissured aiid'brecciated belt at least 250 feet wide that 

trends N. 60° E. for' an-.-undetermined distance. Within this belt 

zones of veins ranging -in trend from N. 10° W. to N. 50° E. and 

dipping steeply to the north and'northwest, consist of quartz, calcite, 

and fluorite. These zones are not continuous or parallel, and pinch 

and swell within short distances. The waste rock between zones of 

veins is brecciated and veined, but the fluorspar-content is negligible. 

Massive quartz veins are common in the area," and one vein forms a 

ridge as much as 10 feet high for a distance of 200 feet northeast of 

the shaft. This quartz vein marks the easternmost limit of the 

fluorspar-bearing zones.

The trenches show a high proportion of fluorite relative to the 

amount of quartz and brecciated andesite. The underground workings expose fewer fluorspar-rich zones, and the proportion of country 

rock and gangue material is much higher.

UTAH MINE

The Utah mine is a mile southwest of the JB claim and may be 

reached by way of the same entrance roads (fig. 3). The Utah mine

is on the Crystal claims, located in 1936 by the Utah Fluorspar Corp.,

of which Bart W. Mortensen, Parowan, Utah, is president. The

claims are under lease to Theo. E. Stevens and R. H. Alsop of Milf ord, 

Utah. In April and June 1943 D. C. Cox, J. 0. Fisher, and A. E. 

Granger of the Geological Survey visited the Utah mine. The 

description of the workings (fig. 7), now inaccessible, is taken from 

their notes.

An almost vertical fault zone, striking N. 45° E., separates andesite 

porphyry on the southeast from rhyolite porphyry on the northwest. 

The fault zone is about 80 feet wide. The greater part of this width 

consists of blocks and masses of altered andesite with veins and fillings
DEPOSITS IN INDIAN RANGE AND MONARCH CLAIMS 15

FIGURE 7. Geologic sketch map of the Utah mine, Beaver County, Utah.

of quartz and calcite. Quartz and calcite are traceable for about 500 

feet in both directions along the strike. Along the northwest margin 

of the fault zone fluorspar is present as seams and lenses as wide as 

2 feet. The fluorspar-bearing part of the fault zone is not more than
16 FLUORSPAR DEPOSITS OF UTAH

20 feet wide, and near the center of this part a section as much as 12 

feet wide contained fluorspar lenses so- closely spaced as to make the 

entire width minable.

The old workings at the Utah mine consisted of a 90-foot vertical 

shaft, a short adit to the old shaft, and a pit 110 feet long. Before 

1940, 12 carloads of metallurgical-grade fluorspar was mined by a 

glory hole from the old shaft; the shaft subsequently caved. In 1942 

Stevens and Alsop sank a new shaft to a depth of 110 feet at a point 

45 feet northeast of the old shaft. A 40-foot drift was driven from 

the 90-foot level to the old glory hole (fig. 7). The fluorspar-bearing 

zone at the new shaft was reported by Cox to be about 8 feet wide, 

about half of which was fluorspar in 1-foot lenses that could be mined 

selectively. According to Stevens, 51/2 carloads of ore averaging 

more than 80 percent of CaF2 was mined during the sinking of the 

shaft and the drifting.

LOST SHEEP AND DUGOTTT CLAIMS

The Lost Sheep and Dugout claims are on the west slope of the 

Indian Peak Eange (fig. 3). They are about 5 miles by road from 

the Cougar Spar mine. E. A. McKenzie leased the Lost Sheep claim 

from J. H. Haslam, and the Dugout claims from C. L. Jones and J. H. 

Haslam.

At the Lost Sheep claim a wide vein zone containing calcite and 

quartz cuts the volcanic rock of the area. A few weathered outcrops 

suggest that the country rock is andesitic. A 25-foot vein of massive 

calcite occurs near the eastern margin of the vein zone. Veinlets of 

fluorspar are exposed in two outcrops, one 200 feet west and the other 

500 feet west of the calcite mass. The fluorspar veinlets occur in

quartz and range in width from. 1 to 6 inches. No economically 

minable width of fluorspar is exposed. The vein zone extends northward a few hundred feet to a gully,'as shown by float of quartz and

calcite. Beyond the gully there is little evidence of the vein zone.

At the Dugout claims a few veinlets of fluorspar occur in a quartz

vein. The veinlets average 3 inches in width and are limited to zones

less than 4 feet wide. One exposure of fluorspar-bearing material is

in a pit near the entrance road; a shallow shaft 15 feet southeast of 

the pit revealed no fluorspar. Fluorspar veinlets are also exposed 

in an outcrop about 1,000 feet southeast.

MONARCH (STAATS) CLAIMS

the Monarch (Staats) claims are in the Wah Wah Mountains, 47 

miles by road southwest of Milf ord, Utah, and about 35 miles by road

northwest of Lund, Utah (fig. 3). The mine is in T. 29 S., B, 16 F,,

in what is sometimes called the Pine Grove mining district. The
DEPOSITS IN INDIAN RANGE AND MONARCH CLAIMS 17

claims are owned by Fred Staats of Salt Lake City. Fluorspar was 

first discovered in the area about 1935, and some ore was mined there

 every year through 1945. The total production to January 1946 is 

about 3,500 tons. The claims have been in several hands and called 

by various names: the Monarch mine, the Skougard mine, the Roberts 

.and Skougard mine, and the Roberts and Staats mine. Recently the 

.area has been referred to solely by the name of the present operator 

.and is called the Staats area. In April 1943 Cox and Fisher visited 

the Staats mine and mapped the relation of the pits and trenches to 

the upper shaft. In March 1945 the writer examined the underground workings and mapped part of them.

The fluorspar deposits occur along the faulted contact of a Tertiary 

rhyolite porphyry and a Cambrian limestone. The wall rocks were 

altered only slightly, but irregular boundaries of some fragments of

 country rock enclosed in massive fluorspar suggest partial replacement. The silica content of the ore is low and is probably derived 

from inclusions of rhyolite porphyry; quartz veins are not present in 

the ore. Some CaCO3 is present, owing to included limestone fragments. The Si02 and CaC03 content did not exceed 5 percent, respectively, and averaged about 2 percent of each. Autunite and 

uranophane were found by Wyant 4 as local coatings on the fluorite. 

Two grab samples of material from some of the pits northeast of the 

main shaft contained 50 and 68 percent of CaF2 . Assays of carload 

shipments of fluorspar that had been selectively mined and sorted 

ranged from 80 to 91 percent of CaF2 and averaged in excess of 85 

percent of CaF2 .

The fluorspar occurs in lenticular shoots within larger podlike ore 

zones. The waste between shoots is composed of brecciated limestone 

:and rhyolite porphyry. Apparently the depth of each shoot is greater 

than the length: the shoots range from 2 to 6 feet wide and from 5 

to 10 feet long, but are reported to extend more than 25 feet in depth. 

The shoots are oriented roughly parallel to the irregular contact zone 

of the limestone and rhyolite porphyry. The contact zone is intricately faulted, with many variations in strike and dip and sharp 

undulations in the trace.

Two separate areas of fluorspar mineralization on the Staats property have been explored. Most of the prospecting centers around the 

main deposit at the head of the valley (fig. 8) but a small deposit has 

been opened about half a mile southeast (fig. 9).

The principal workings at the main deposit (the Staats mine) are 

an 85-foot shaft, an opencut, and an adit. This deposit was first explored by an opencut; then a shaft was sunk about the middle of the 

openGut, v ,and stopes were driven at various levels from the shaft. At

4 Op. cit. on p. 5 ; p. 3.
18 FLUORSPAR DEPOSITS OF UTAH

Geology by D. C. Cox and J. O. Fisher. June 1943

Adit mapped with compass and tape by 

W. R. Thurston. March 1945

FIGURE 8. Sketch map of geology in vicinity of main shaft, Staats mine, Beaver County,.

Utah,

the 85-foot level a drift extends 65 feet southward. About 400 feet 

southeast of the shaft an adit exposed several pockets Of fluorspar 

along a faulted segment of the contact between the rhyolite porphyry

and limestone (fig. 8). Because of caving ground, only a small part 

of the shaft-workings was accessible for examination. Apparently 

enough fluorspar remains in the vicinity of the shaft to be worthrecovering. Within 600 feet to the north, northeast, and southeast,, 

several pits and trenches show fluorspar in the contact zone.
DEPOSITS IN. STAR DISTRICT; BEAVER COUNTY 19

Workings in part projected to plane of section

Small fault, approximately located

Umlt of fault breccia zone

Pace and compass sketch by W. R. Thurston, March 1945

FIGURE 9. Geologic sketch map of winze operation, Staats mine, Beaver County, Utah.

An adit about half a mile to the southeast leads to a winze operation 

from which 200 tons of ore was mined in 1944 (fig. 9). The ore in 

the winze formed a shoot 10 feet long, 6 feet wide, and about 55 feet 

deep.

DEPOSITS IN STAR DISTRICT, BEAVER COUNTY

ByD.C.Cox

The Star district is about 8 miles west of Milf ord in Beaver County 

(fig. 3). It was one of the early copper-lead-zinc-silver mining camps 

of Utah and was most active during the 1870's. The district has been 

described by B. S. Butler (1913, p. 96, 114-136, 194-206, and pi. 1).

Fluorspar occurs in the Star district as a gangue mineral in some 

of the metal ores, and as seams and veins genetically related to these 

metal deposits but located outside them. The fluorspar in the ores 

of copper, lead, zinc, and silver was not recovered. The calcium 

flupride content and the tonnages of ores mined at the Moscow,mine
20 FLUORSPAR DEPOSITS OF UTAH

in 1945 were too low to warrant separate installation of mill facilities 

to recover byproduct fluorspar. Fluorspar from the outlying small 

veins and seams is easier to concentrate and, therefore, has been mined 

from pits, trenches, and a few shallow shafts.

In June 1945 D. C. Cox and J. O. Fisher, accompanied by Theo. 

E. Stevens, examined parts of the Star district. The fluorspar-bearing 

areas in the district were under lease to the Western Fluorite Co., 

of which Mr. Stevens is president. The properties examined, and 

others reported to contain fluorite, are listed in table 1 and shown in 

figure 10.

R. 12 w. R. 11 W

'11

Western Fluorite

T. 

29 

S.

IMile

Claim locations from Ti Stevens and D. C. Cox, June 1943

EXPLANATION

1. Wild Bill

2. Brown Thrush

3. Lucky Boy No. 1

4. Fluorine Ledge

5. Lucky Boy No. 2

6. Monte Cristo

r [ Moso

FLUORSPAR LOCALITIES

7. Manassa

8. Local

9. Burning Moscow

10. Hub

11. Lady Bryan

12. Virginia No. 1

LOCATIONS OF ROADS IN NORTHWEST PART ARE APPROXIMATE

13. North Virginia Extension

14. Virginia No. 2

:OW 15. Virginia No. 3

16. Virginia No. 4

17. Quartzite

18. Cabin

FIGURE 10. Index map showing fluorspar localities In the Star district, Beaver County,

Utah.
DEPOSITS -IN STAR DISTRICT, BEAVER COUNTY 21

TABLE 1. Fluorspar localities in the Star district, Beaver County,'Utah 

Claim or mine Owner and address as of June 1943 

Brown Thrush claim ____________ Theo. E. Stevens, Milf of d, Utah.

Cabin claim__________________ Do.

Eluorine Ledge -claim_________ James Beaudino, Cedar City, Utah,. and

Lawrence Dotson, Minersville, Utah.

Hub mine.------__-_---------- Unknown.

Lady Bryan raine_._____________ Do.

Lucky Boy No. 1._______.-_-_-_ Do.

Lucky Boy No. 2 claim.________ Theo. E. Stevens, Milford, Utah.

Manassa claim.________________ R. H. Alsop, Theo. E. Stevens, and Adam

Patterson, Milford, Utah!

Monte Cristo mine..___________ Silver Cedar Mining Co.

Moscow mine____---__------___ Silver Mines Co.

North Virginia Extension claim.__ Theo. E. Stevens, Milford, Utah.

Quartzite claim._.__-__--_______ Ralph Mvers and Lawrence Dotson, Minersville, Utah.

Virginia claims. __ ____--_-____-_ Thomas Gillens, Minersville, Utah.

Wild Bill mine.________________ Unknown.

The fluorite occurs as fissure fillings in limestone on the Fluorine 

Ledge, Lucky Boy No. 2, and Cabin claims, in quartzite on the 

Quartzite claim, and in quartz monzonite on the Virginia claims. On 

the Hub, Lady Bryan, Moscow, Wild Bill, Monte Cristo, and Manassa 

claims the fluorite is associated with sulfide ores and contactmetamorphic minerals. At the Wild Bill, Moscow, Lady Bryan, 

Monte Cristo, and Manassa mines the introduced minerals fill fissures 

in limestone and replace limestone near but not at the contact with 

quartz monzonite. Similar deposits are found at the Hub mine, but 

most of the deposits are confined to the contact zones.

DESCRIPTION OF INDIVIDUAL DEPOSITS

BROWN THRUSH CLAIM

On the Brown Thrush claim (fig. 10), fluospar occurs with quartz 

in a zone of veins in limestone, probably the Red Warrior limestone 

Silurian (?) and Devonian (?). The zone, which is 15 to 20 feet 

wide, strikes N. 20° W., and was traced for about 100 feet. Coarsely 

crystalline fluorite occurs in small patches in the zone; where most 

abundant, it constitutes a maximum of 20 percent of the vein material. 

A fissure trending N. 60° W. and cutting the zone of veins contains 

oxidized copper, lead, and zinc minerals, according to Stevens. The 

dump from the 40-foot shaft on the fissure vein contains sulfide 

minerals. A little medium-grained fluorspar forms gangue in the 

oxidized and sulfide ores.

CABIN CLAIM

On the Cabin claim (fig. 10) a 30-foot inclined shaft exposes several drusy quartz veins, 1 foot thick, containing coarsely crystalline 

fiuorite in seams less than 5 inches wide. The veins lie along bed-
22 FLUORSPAR DEPOSITS OF UTAH

ding planes in limestone, probably the Elephant limestone (Carboniferous) which was mapped by Butler to a point within iy2 miles 

north of the Cabin claim. The limestone strikes N. 5° W. and dips 

30° E. Southward the veins end at a fault striking N. 75° E. and 

dipping 85° N. A little fluorspar occurs along this fault.

FLUORINE LEDGE AND LUCKY BOY NO. 2 CLAIMS

Fluorite and quartz occur on the Fluorine Ledge and Lucky Boy 

No. 2 claims (fig. 10) in irregular fissure veins and along bedding 

planes of a limestone mapped as Red Warrior limestone by Butler. 

The limestone beds strike from N. 20° E. to N". 20° W. They dip 

eastward at angles of 20° to 30° in most of the region, but at the 

north end of the Fluorine Ledge claim they apparently dip steeply 

west. The fluorite is green to colorless and coarsely crystalline. At 

some places it has distinct cube faces. Most of the fluorspar was 

produced from a pit about 15 feet long and 4 feet deep near the 

south end of the Fluorine Ledge claim. According to Stevens, the 

ore came from a vein that was 5 feet wide at the surface and 18 

inches wide at the bottom of the pit. It probably followed the limestone bedding, which dips about 30° E. Only small patches of fluorspar are present in the north end of the pit, and none in the south end.

A shallow pit near the south end of the Lucky Boy No. 2 claim 

exposes an eastward-striking vertical vein of coarse light-green to 

almost colorless fluorspar. Cleavage fragments of fluorite as much 

as 2^ inches across can be obtained. The vein has a maximum width 

of 2'feet and is very irregular. The pit is 30 feet northeast of an 

outcrop of an intrusive body mapped as quartz monzonite by Butler. 

Small veins of fluorspar are exposed in other shallow pits, and have 

a maximum width of about 6 inches.

HUB, LADY BRYAN, MONTE CRISTO, MOSCOW, AND WILD BILL MINES AND

MANASSA CLAIM

The Hub, Lady Bryan, Monte Cristo, Moscow, and Wild Bill mines 

(fig. 10) are old copper-lead-zinc-silver mines that were most active 

in the early 1870's. Butler (1913) has described the deposits of the

Hub (p. 201-203), Lady Bryan (p. 203-204), Moscow (p. Q01-20Q),

and Wild Bill (p. 196-197) mines. Fluorite is associated with muscovite, magnetite, galena, sphalerite, pyrite, and chalcopyrite at the 

Hub mine; with muscovite, epidote, pyroxene, and tremolite at the

Lady Bryan mine; and with garnet, diopside, magnetite, specularite,

and sulfide ores at the. Wild Bill mine,

The surface exposures at the Monte Cristo and Moscow mines and 

a tunnel at the Manassa claim were examined. At the Monte Cristo 

mine, fluorspar veinlets in limestone are exposed near the collar of
DEPOSITS IN STAR DISTRICT,,. BEAVER COUNTY 23

the inclined shaft and about 100 feet north of it. The shaft follows 

an eastward-dipping fault between quartz monzonite on the east and 

limestone on the west.

The Moscow mine was being worked in June 1943 for sulfide ores 

containing galena, sphalerite, pyrite, and chalcopyrite. Mediumgrained fluorite occurs as a gangue mineral with rhodochrosite and 

sericite. According to Stevens, the ore contains as much as 20 percent of CaF2 . Fluorite also occurs with a fibrous amphibole in altered 

dikes.

Medium-grained fluorspar occurs on the Manassa claim in a contactmetamorphic deposit in limestone and is associated closely with a 

fibrous amphibole and less closely with garnet. Little is known of 

the extent of the fluorspar zone, but it is probably very irregular. 

A fluorspar zone 2 to 3 feet wide was seen in the end of a 200-foot 

tunnel. The grade of the fluorspar in the tunnel is probably not more 

than 20 percent CaF2 . Little fluorspar is exposed on the surface.

QUARTZITE CLAIM

On the Quartzite claim (fig. 10) a vein of coarse-grained fluorspar 

is exposed in a shallow pit along a bedding plane in quartzite. The 

quartzite is probably a lens in the Harrington formation (Triassic). 

The bedding strikes N. 20° E. and dips 45° E. The fluorspar vein has 

a maximum thickness of about 2 feet, and about 10 tons has been 

mined from it. At the north end of the pit a little fluorspar is 

found in a fault that strikes east and dips 75° S. between the quartzite and a limestone north of it.

VIRGINIA AND NORTH VIRGINIA EXTENSION CLAIMS

Fluorspar occurs on the Virginia claims (fig. 10) in quartz-fluorite

 veins in an intrusive rock, probably a part of the southernmost body

 of quartz monzonite mapped by Butler.

In a 15-foot inclined shaft on the Virginia No. 2 claim, an irregular 

vein striking N. 30° W. and dipping 30° SW. is exposed. The maximum vein width seen is 2 feet, but Stevens states that part of the 

vein now mined out had a width of 4 feet. Probably about 50 tons 

was mined. One shipment from the shaft contained 73 percent of

 CaF2 .

On the Virginia No. 3 claim a shallow open cut about 40 feet long

 exposed an eastward-striking lens of fluorite, calcite, and quartz, 

which, according to Stevens, was as much as 6 feet wide and contained 

'60 to 70 percent CaF2 . The dip at the surface was about 20°, but 

:steepened to about 40° at a depth of 5 feet; the lens narrowed at this

 depth. Probably about 50 tons of fluorspar has been mined. Only 

.small fluorspar veinlets are exposed at the ends of the pit.
24 , FLUORSPAR DEPOSITS OF UTAH 1 . v< ' ./' - / . ;,

Fluorspar veinlets are found in the quartz monzonite on the Virginia No. 1 and North Virginia Extension claims, and, according 

to Stevens, also between the Virginia No. 1 and Virginia No. 2 workings and on the Virginia No. 4 claim.

DEPOSITS IN THOMAS RANGE DISTRICT, JUAB COUNTY

By M. H. Staatz, V. R. Wilmarth, and H. L. Bauer, Jr.

The Thomas Range fluorspar district in Juab County is one of 

the newest mining districts in the western United States. The first 

producing mine was opened by the Spor brothers in 1943, and largescale mining began in 1948 after the discovery of the Blowout, Fluorine Queen, and Lost Sheep deposits; by September 1950 the district 

had produced 35,700 short tons of fluorspar. The abnormal radioactivity of the fluorspar has aided in the discovery of new deposits.

The Thomas Range is a northwest-trending group of mountains 

that includes Topaz Mountain, about 7,110 feet high. The fluorspar 

deposits are in the western branch of the range, called "Spor's Mountain" by Fitch, Quigley, and Barker (1949, p. 63-66). Spors Mountain is in Tps. 12 and 13 S., R. 12 W., Salt Lake principal meridian 

(fig. 1). It is about 6 miles long, and the highest peak is about 6,600 

feet in altitude. The deposits are accessible by mine roads that connect with haulage roads on both sides of Spors Mountain (fig. 11). 

The haulage roads join the Callao-Delta road 57 miles west of Jericho, 

Utah, and 45 miles northwest of Delta, Utah.

In November 1943 A. E. Granger of the Geological Survey examined the Floride (Original Spor) mine, and in August 1944 the deposit was visited by W. R. Thurston and E. D. Washburn. The Spor 

mine has been revisited by members of the Geological Survey several 

times since then. No geologic maps of the Thomas Range have been 

published, but some mapping has been done by W. P. Fuller of. the 

International Smelting & Refining Co., and by James Quigley of 

Centennial Development Co., Eureka, Utah. The district has been

described by Fitch, Quigley, and Barker (1949). The fluorspar deposits were mapped and Studied in August 1950 by M. H. Staatz and 

H. L. Bauer, Jr., and in September 1950 by V. B. Wilmarth and H. L.

Bauer, Jr., as part of an investigation of uranium resources being

Carried out by the U. S. Geological Survey on behalf of the Atomic 

Energy Commission.

The writers are indebted to the mine operators for making available information and in giving other assistance. They are grateful 

to Mr. James Quigley for permission to use figure 11. Mr. Quigley 

and Mr. W. P. Fuller were generous in giving of their knowledge 

of the geology of the district in discussions of the Thomas Range 

deposits.
DEPOSITS IN THOMAS RANGE DISTRICT, JUAB COUNTY 25

R.I2 W._______'" ___________ R. II W.

From unpublished map, after J. Quigley CentenniaV Development Co 

March 1950

FIQUKH 11. Index map of the Thomas Range district, Juab County, Utah.

Fluorspar has been produced from 12 deposits on 8 properties 

through September 1950, as summarized iii table 2. The material 

shipped generally contained 65 to 94, percent CaF2 , less than 2 percent silica, and less than 5 percent calcium carbonate. The chief 

impurity is clay; phosphorous and sulfur are generally absent.
26 FLUORSPAR DEPOSITS OF UTAH

TABLE 2. Fluorspar produced in the Thomas Range district, Juao County, Utah,

through September 1950 .

Property

Florida ........

Dell Ncs. 1,2, and

3. 

Dell No. 5........

Fluorine Queen.. 

Blowout.--.-...

Lost Shrep __ ..

Bell Hill.. .---...

Thursday No. 3..

Total......

Owner

Spor.

T. A. Claridge, Earl WUlden,

Albert Willden, Lafe Morley. 

W. E. Black, F. B. Chesley . T. A. Claridge, Rex Claridge

Albert Willden, Earl Willden

H. J. Euthiford, D. W.

Searle, C. D. Searle, H. E. 

Searle. 

W. L. Hamblin, O. D. 

Hamblin, A. W. Hamblin.

Operators

Spor.

O. P. Spor, Chad Spor, Ray

Spor.

W. E. Black,- F. B. Chesley.. 

T. A. Claridge...... ... . ...

Albert Willden, Earl Willden.

Chad Spor, G. P. Spor, Ray

Spor.

W. L. Hamblin, O. D. 

Hamblin, A. W. Hamblin.

Number 

of deposits 

that - 

produced 

fluorspar

3

. 1

2 

1

1

2

1

Production 

(short 

tons)

10,285

1.7, 000

!.' 275

6, 770 

3,000

6,400

1, 870

100

35, 700

GENERAL GEOLOGY

The Thomas Kange is composed of Paleozoic sedimentary rocks and 

Tertiary volcanic rocks. The eastern part of the range is made up 

principally of rhyolite tuffs and flows that are capped by a fine-grained 

gray, massive topaz-bearing rhyolite. The western part of the range, 

Spors Mountain, is underlain by an older quartzite, several hundred 

feet thick, and a thick sequence of younger dolomite. These rocks 

have been complexly step-faulted by steeply dipping normal and 

reverse faults, and intruded by plugs and dikes of rhyolite porphyry. 

Uraniferous fluorspar deposits occur in dolomite and intrusive breccia 

in the western part of the Thomas Range. Thin conglomerates, deposited along the shores of Pleistocene Lake Bonneville, are found 

locally along the base of Spors Mountain.

The quartzite forms prominent outcrops and is a thick-bedded rustyweathering rock. It crops out along the eastern side of Spors Mountain and, according to W. P. Fuller (personal communication) extends 

eastward to a fault of several thousand feet displacement on the east 

side of Spors Mountain. . ; ;

The dolomite ranges from light gray to black and from fine to coarse 

grained. Some beds contain as much as 20 percent chert. The writers 

found fossils of Silurian age in them. . I

The Paleozoic rocks strike N. 20° to 40° E. and dip 25° to 45° ; W. 

Three sets of steep normal and reverse faults form a step-block pattern

that causes many repetitions and omissions of individual beds. Fuller

(personal communication) has noted north-striking and northeaststriking sets, and the writers also noted an east-striking set at the Bell 

Hill and Harrisite properties. The displacements range from a few 

feet to several thousand feet. Most of the faulting took place before
DEPOSITS IN THOMAS RANGE DISTRICT, JUAB COUNTY 27

the emplacement of the volcanic rocks, but postemplacement faults of 

small displacement are known.

Plugs and dikes of intrusive breccia commonly made up of rhyolite 

porphyry fragments in an aphanitic groundmass intrude the dolomite. 

The rhyolite porphyry is commonly white and contains phenocrysts 

of quartz and orthoclase one-eighth inch long in an aphanitic groundmass. The groundmass of unaltered rhyolite porphyry fragments is 

chiefly orthoclase and a few percent of quartz and euhedral topaz. 

Commonly the orthoclase of the rhyolite porphyry fragments associated with fluorspar deposits is altered to clay minerals and sericitized, 

and topaz is absent from the altered rock. The intrusive breccia does 

not crop out at the surface, but the shapes of the intruded bodies in 

most places are outlined by outcrops of the more resistant adjacent 

dolomite. In some places the soft altered intrusive breccia is veined 

by fluorite. The intrusive rock is presumed to be of Tertiary age because similar extrusive rocks east of the Thomas Range, 7 miles southwest of Levan, Utah, have been dated thus (Muessig, 1951, p. 234).

All the fluorspar deposits discovered so far are epithermal pipelike 

bodies or veins and occur in dolomite or rhyolite porphyry but not in 

quartzite. The deposits are either vertical or steeply dipping. Circular or oval pipelike bodies have been the source of about 95 percent of 

the fluorspar mined in the district. These bodies range in size from 

15 feet in diameter to 176 feet long and 103 feet wide (east pipe, Fluorine Queen, fig. 14). The pipes commonly are associated with faults. 

The margins of the fluorspar bodies are sharp, and soft fluorspar is 

commonly in contact with unaltered dolomite (pi. 7A]. At the Blowout property (fig. 12) the fluorspar pipe is partly in contact with an 

altered intrusive breccia plug; at the Harrisite property (pi. 8) a 

fault that cuts dolomite and altered basalt contains fluorspar.

Irregular pipelike bodies have ragged margins, and veinlets of 

fluorite extend outward into dolomite (pi. IB). Blocks of dolomite 

as much as 6 feet in diameter commonly are included in the fluorspar 

bodies, as in pit No. 1 of the Bell Hill property. An east-striking 

fault along the west wall of pit No. 2 on the Bell Hill property (pi. 5) 

is marked by well-developed slickensides, but in most irregular deposits 

no fault surfaces are evident. These deposits probably formed close 

to faults along related zones of closely spaced fracturing in the 

dolomite.

The irregular pipelike bodies range in size from 10 feet wide and 

25 feet long (trench 3, Bell Hill property, pi. 5) to 25 feet wide and 145 

feet long (pit No. 2, Bell Hill property, pi. 5).

Veins of fluorite are common, but only at the Thursday No. 3 property (fig. 17) has a vein yielded fluorspar in commercial quantities. 

The veins range o in size from a few inches wide and a few feet Ions oto

14 feet wide and 246 feet long. Most of the veins are along fractures in
28 ' 'FLUORSPAR DEPOSITS OF UTAH

dolomite, but a few are localized along faults in rhyolite porphyry 

dikes, as in trench No. 3, Harrisite property (pi. 8) and on the Thursday property (fig. 17).

White to deep-purple fluorite constitutes 65 to 95 percent of each 

deposit. It is soft and closely resembles a white to purple clay. Clay 

minerals, dolomite, calcite, carnotite, quartz, and opal are the other 

minerals visible. The fluorspar of most properties contains 2 percent 

or less silica, but some contains at least 20 percent. The calcite and 

dolomite contents are low except in a few deposits, such as at the Bell 

Hill and Harrisite properties. The Geneva Steel Co. reported (Fitch, 

Quigley, and Barker, 1949, p. 65-66) that the first ore shipped from the 

Floride claim contained 95 percent CaF2 and 1 percent Si02 , no phosphorous, and no sulfur. The first 35 cars shipped from this property 

averaged more than 90 percent CaF2 and less than 2 percent Si02 . 

About 100 railroad cars of ore were shipped from the Lost Sheep 

property; it assayed more than 90 percent CaF2 and less than 1 percent 

SiO2 . One carload lot was reported to have the following analysis: 

94.90 percent CaF2 , 0.44 percent SiO2 , 1.12 percent CaO, 0.32 percent 

MgO, 0.012 percent S, and 4.5 percent H2O. The first 35 carloads of 

fluorspar from the West pipe on the Fluorine Queen property contained 70 to 90 percent CaF2 and less than 2 percent SiO2 ; the lower 

grade ore came from near the surface.

All the fluorspar deposits are abnormally radioactive, but generally 

no uranium minerals can be seen. Assays of 45 fluorspar samples 

ranged from 0.005 percent to 0.33 percent uranium. Samples from 

three deposits on the Bell Hill, Harrisite, and Eagle Kock properties 

contained more than 0.1 percent uranium. Carnotite was noted only 

in the fluorspar at the Eagle Rock property, the Floride property, 

and in the West pipe at the Fluorine Queen property. At the Bell 

Hill and Harrisite properties carnotite is found in the adjacent 

country rock but not in the fluorspar.

SUGGESTIONS FOB PROSPECTING

The most favorable place to find fluorspar deposits is in areas 

adjacent to faults and intrusive breccia pipes. A detailed geologic

map of the faults and intrusive bodies in the area would show most of 

the places favorable for finding fluorspar deposits.

Most of the fluorspar .is radioactive, and traversing the surface 

with Geiger-Mueller counters should assist in delineating favorable 

areas for prospecting. Oval or circular areas surrounded by dolomite

outcrops are favorable sites for finding concealed, intrusive breccia

or fluorspar bodies; many of these areas are shallow depression? filjed

with dolomite and. chert float and can be 'prospected by "bulldozing,

Float is an invaluable aid in prospecting in,.this district.,,,.The

fluorspar float is very soft and is rarely found far from the deposits.
GEOLOGICAL SURVEY!

A, Fluorspar pipe at Floride (original Spor) mine, Juab 

County, Utah. View eastward across workings, May 1945.

B, Pit V
DEPOSITS IN THOMAS RANGE DISTRICT, JTJAB COUNTY 29

Commonly it is included in the debris surrounding anthills, and rabbit and other animal burrows above the deposits.

In the southern part of Spors Mountain, where the relief is low 

and overburden is thick, the best method of prospecting in absence of 

float, is to make a geologic map of the area and to cut with bulldozer 

trenches the favorable areas that are revealed by the mapping.

DESCRIPTION OF INDIVIDUAL DEPOSITS

BELL HILL PROPERTY

The Bell Hill property (fig. 11) is on a hill about 200 feet high 

at the southern end of Spors Mountain. It is in sec. 10, T. 13 S., B. 12 

W., Salt Lake principal meridian. The Bell Hill group of claims was 

staked July 17, 1949 by H. J. Kuthiford, D. W. Searle, C. D. Searle, 

and H. E. Searle. The claims have been leased by G. P. Spor of 

Delta, Utah, who was actively mining them in September 1950. 

Thirty-four cars of fluorspar, averaging 55 tons each, were mined 

and shipped between July and September of 1950. This material had 

an average CaF2 content of more than 70 percent.

Workings on the Bell Hill property (pi. 5) consist of three stripped 

areas and two open pits. Pit No. 1, from 10 to 26 feet deep, is on the 

largest fluorspar body. About one carload of fluorspar a day was 

being shipped from this pit in September 1950.

The fluorspar bodies occur in gray cherty dolomite under a cover 

of dolomite float. Outcrops of the dolomite are not conspicuous, and 

poor exposures make it difficult to recognize faults in the homogeneous 

dolomite. A fault is well exposed along the north side of pit No. 2: 

it strikes N. 76° E. and dips 65° SE. Grooves and slickensides on the 

fault plane plunge 54° S. 65° E. The other fluorspar bodies on the 

property probably formed along faults also, but evidence of the faults 

has been destroyed by the introduction of the fluorite.

At least five fluorspar deposits are exposed in the workings at the 

Bell Hill property. Trench No. 1 contains two 6-foot veins and a 

6-inch stringer of fluorspar, trench No. 3 exposes a 3- and a 9-foot 

vein of fluorspar. The fluorspar presumably has replaced the dolomite along faults or small shears. The deposits have a general linear 

trend but in detail are extremely irregular. Four of the bodies 

trend nearly east, and the fifth strikes northeast. All, except the 

fluorspar body in pit No. 2, are essentially vertical (pi. 5). In pit 

No. 1 a boulder of dolomite, 6 feet in diameter, was completely surrounded by fluorspar. The shape of the deposit in the northwesttrending segment of the deposit in pit No. 2 is extremely irregular 

(pi. 7B). The fluorspar extends outward into the dolomite along a 

series of parallel shears, and the edge of the body has a serrate 

appearance. ' .

286657 54 3
30

Two small bodies, or a branching deposit, are exposed in trench 

No. 3. The east exposure is 24 feet long and as much as 10 feet 

wide; the west exposure is 9 feet long and as much as 2.5 feet wide.

The fluorspar in pit No. 2 averages 25 feet in width and 145 feet 

in length, and is very irregular, especially in the northwest-trending 

part. It was mined to a maximum depth of 15 feet.

The largest deposit is in pit No. 1 and is split by a mass of dolomite. 

The body has an exposed length of 130 feet and a maximum width 

of 45 feet at the junction of the split. Mining was in progress at a 

maximum depth of 26 feet in this pit in September 1950. Carnotite 

was found as a coating on the gray dolomite adjacent to the fluorspar 

body in pit No. 1. »

BLOWOUT PROPERTY

The Blowout property (fig. 11) is in the south-central part of 

T. 12 S., R. 12 W., Salt Lake principal meridian. The claim was 

located on May 10,1948 by T. A. Claridge and Eex Claridge of Delta, 

Utah. The mine is accessible over a dry-weather road along the 

western side of Spors Mountain that connects with the main haulage 

road 3 miles to the south. A total of 3,000 short tons of fluorspar, 

averaging 75 percent CaF2, has been produced from a pipe on the 

property (fig. 12).

The Blowout deposit has been developed by a large opencut and a 

crosscut 240 feet below the opencut. The opencut trends N. 70° W. 

and is 150 feet long. It averages 30 feet wide and is 57 feet deep at

the western edge of the cut. At 500 feet from the portal the crosscut

intersects the deposit exposed in the opencut. The crosscut was

driven by the owners of the Lost Sheep and the Blowout mines for

use jointly as a haulage adit.

At the Blowout property intrusive breccia intrudes dolomite (fig. 

12). The dolomite beds strike N. 43° E. and dip 34° to 43° NW. The

opencut contains exposures of the contacts between dolomite, intrusive

breccia, and fluorspar. The intrusive breccia is now a hematite-stained 

clay containing calcite. Fragments of this rock found on the dump

show rounded phenocrysts of smoky quartz and remnants of feldspar

crystals in an altered, hematite-stained matrix. The dimensions of 

the igneous body could not be determined because it is partly covered

by dump material, In spite of the apparent relationship of the intrusive breccia cutting across the fluorspar body, as shown in figure 12?

field study indicates that the intrusive breccia is earlier.

The fluorspar is exposed in the pit as an irregular pipelike deposit

that averages about 30 feet wide and 110 feet long. At the northern

edge of the opencut a fissure-type extension of the deposit, 17 feet wide, 

extends for 37 feet along the northwestern edge of the igneous body. 

Fluorspar is exposed to a depth of 57 feet in the opencut and the cross-
DEPOSITS IN THOMAS RANGE DISTRICT, JUAB COUNTY 31

.5760"

5720

5680-

. 5640

EXPLANATION

Fluorspar.

Approximate contact

*Z?

Opencut

3*y

Strike and dip of beds

' mm/// .

Dump

.Geology and topography by V. R.Wilmarth and H. L Bauer. Jr., 

September 1950

FIGURE 12. Map and section of the Blowout property, Juab County, Utah.

-cut intersects the deposit at 240 feet below the level of the opencut; 

the size of the deposit at that depth is not known. A 6-inch zone of

-dolomite at the contact has been altered to fine-grained sugary dolomite containing thin stringers of calcite. The fluorspar is white, pale

-violet, or dark purple. It ranges from a soft white to a hard, dark-
32 FLUORSPAR DEPOSITS OF UTAH

purple, boxwork type of ore. The carload lots that had been shipped 

by 1950 assayed 75 to 80 percent CaF2 .

'.,'.' : DELL NOS. 1, 2, AND 3 CLAIMS

/ The Dell Nos. 1, 2, and 3 claims (see fig. 11) are on the east slope 

of Spors Mountain, in the southeast part of T. 12 S., R. 12 W., Salt 

Lake principal meridian.

The original location was made in the spring of 1947 by Earl 

Willden, T. A. Claridge, and Lafe Morley, all of Delta, Utah, who 

drove an adit about 100 feet long toward a small body of ore at the 

northern end of the property. The claims were sold in 1948 to the 

Ward Leasing Company, who continued this adit about 15 feet to the 

deposit; this company also drove a haulage adit, 933 feet long, S. 60° 

W. from a point 1,500 feet southwest of the small deposit. This adit 

prospected a large fluorspar body, known as the main or western body.

The country rocks at the Dell Nos. 1, 2, and 3 deposits are dolomite, 

quartzite, and plugs of intrusive breccia. The dolomite is a dark-gray, 

crystalline rock containing much chert and is commonly brecciated 

along fault zones. A rhyolite porphyry intrusive body crops out near 

the center of a large intrusive breccia plug. This rock has phenocrysts 

of 'orthoclase and smoky quartz in a siliceous groundmass partly replaced by fluorite. All gradations can be observed from unaltered 

rhyolite porphyry to rhyolite porphyry in which only the quartz 

phenocrysts remain unaltered in a completely altered groundmass. 

Most of the orthoclase is highly kaolinized; a little sericite also was

formed.

The main, or western body, 30 feet wide and 50 feet long, is oval 

in dOSS section and is intersected 200 feet below the surface by a 50- 

foot raise from the 933-foot long adit. This deposit is in dolomite 

and ends against the underlying quartzite exposed at the top of the 

raise. A smaller body, 32 feet in diameter, was cut 40 feet from the 

portal of the long haulage adit. Both bodies have been mined out. 

About 7,000 short tons of fluorspar containing 80 percent CaF2 WaS

produced. The material as shipped contained 3 to 4 percent SiO2 and

1 to 2 percent CaC03 .

A third body, 10 feet long and 8 feet wide, is exposed about 800 feet 

north of the portal of the long haulage adit, and is intersected about 

35 feet below the surface. The deposit was stoped for 25 feet above

and 25 feet below the adit level. The deposit pinched out against 

quartzite at the bottom of this stope. About 100 tons of fluorspar

 was produced.

An unmined, siliceous fluorspar vein occurs in the intrusive breccia 

plug near the portal of the 115-foot adit. This fluorspar vein is 40 

feet long and averages 1.5 feet in thickness.
33

DELL NO. 5 PROPERTY

The Dell No. 5 property (fig. 11) is in a small gap on the crest of 

Spors Mountain, in the southeast part of T. 12 S., R. 12 W., Salt Lake 

principal meridian. The workings are reached from the main haulage 

road by a private road about 1 mile long. The Dell No. 5 claim was 

located originally by Earl Willden, Albert Willden, T. A. Claridge, 

and Lafe Morley. It was leased for a period by the Spor brothers, 

who made the road, did the development work, and took out about 

275 tons of fluorspar.

Two fluorspar deposits are on the property. The one nearest the 

road (the south body) was mined from a 60-foot adit that intersected 

the deposit about 25 feet below the surface. This body was stoped 

for 15 feet above and below the adit level. The other deposit (the 

north body) is partly exposed by bulldozer workings and is prospected 

by an adit about 15 feet long.

The country rock is a dark-gray dolomite containing some chert 

A rhyolite porphyry plug, about 25 feet in diameter, cuts the dolomite. 

Phenocrysts of white, euhedral orthoclase, as much as one-sixteenth 

of an inch long, and quartz, as much as one-eighth of an inch long, 

.make up about 35 percent of the rhyolite porphyry1 ; the rest is an 

aphanitic white groundmass consisting chiefly of slightly kaolinized 

orthoclase and some clear topaz. The topaz forms euhedral crystals 

enclosed in both quartz and "orthoclase and appears to .have been the 

earliest mineral to crystallize.

The two fluorspar bodies are about 230 feet apart. The south body 

is about 15 feet in diameter and contains friable white to purple 

iluorite. The north body is incompletely exposed but has a minimum 

size of 15 feet by 20 feet in plan. The fluorspar is in part powdery 

but contains many hard ribs of siliceous material. It has been reported 

that a chip sample from the walls of the small adit contained 91 percent CaF2 and 0.97 percent silica.

EAGLE ROCK PROPERTY

The Eagle Rock property (fig. 11) is on the east side of a low range 

of hills about 300 feet high, which are in the valley separating the 

western and eastern parts of the Thomas Range, in the southeast 

part of T. 12 S,, R. 12 W., Salt Lake principal meridian. The Eagle 

Rock property consists of the Eagle Rock and Eagle Rock No. 1 claims; 

These claims were located on August 15,1948, by T. A. Claridge, Rex 

Claridge, Albert Willden, and Earl Willden, all of Delta, Utah.

On the Eagle Rock property (fig. 13) a fluorspar vein is exposed 

in a trench and a pit about 250 feet above the valley bottom and the 

nearest road. The trench is 30 feet long, 4 feet wide, and a maximum 

of 12 feet deep. The pit is 4 feet square, and is 20 feet southwest of
34 FLUOESPAR DEPOSITS OF UTAH

the trench. Five other prospect pits have been made in intensely 

altered dolomite.

The country rock on the Eagle Rock claims consists of a fine-grained, 

dense, gray dolomite containing a fine network of chert. The dolomite 

strikes N. 43° E. and dips 30° NW. In the central part of the property 

a depression is covered by slope wash (fig. 13) ; similar smaller depressions are found elsewhere on the property. The general circular 

shape of the depressions, the brecciated and silicified dolomite in the 

surrounding outcrops, and the presence of calcite-rich, cream to reddish claylike material in the pits suggest that the depressions formed 

in hydrothermally altered dolomite above intrusive plugs.

The fluorspar body exposed on the Eagle Eock property (fig. 13) 

is extremely irregular in size and shape. It is 4. feet wide at a depth 

of 6 to 12 feet in the middle of the trench and is absent at a depth of 

2 feet. At 14 feet from the north end of the trench, half a foot of 

fluorspar is exposed, and at 24 feet the vein is 4 feet wide; several 

small patches of fluorite were found between these two exposures. 

The deposit is vertical and in the trench and pit has a minimum length 

of 40 feet.

The fluorspar is dark purple and is mixed with at least 30 percent < 

of silica that forms a fine boxwork structure. This material is unusually hard and resistant in contrast to the powdery fluorspar common 

in the district. The fluorspar is enclosed in white soft limy material 

that is probably calcite resulting from alteration of the dolomite. 

Carnotite coats the fluorite in some places. This body is one of the 

few in the district that contain visible uranium minerals with the

fluorite.

FLORIDE (ORIGINAL SPOR) MINE

The Floride (Original Spor) mine (fig. 11) was the first property 

operated in the Thomas Range district. It IS Oil tuft eaSteiH Slope Of

Spors Mountain, at an altitude of about 5,300 feet, in the SWa/4 sec. 27 

T. 13 S., R. 12 W., Salt Lake principal meridian. The mine is easily

accessible over a Steep road that leads westward from the main, haulage road. The Floride property was staked on January 1, 1941,

by Chad Spor, G. P. Spor, and Ray Spor, -who operated the mine

intermittently between 1941 and 1950. The total production of fluOIspar through 1950 is 10,285 short tons that averaged 80 to 85 percent

CaF2 .

The Floride deposit has been mined by shrinkage methods from two

haulage adits (pi. 6). The upper adit is about 130 feet long and intersects the deposit 40 feet below the surface. The lower adit is about 

275 feet long and cuts the deposit about 80 feet below the surface. On 

this level, two crosscuts have been driven. The crosscut to the south 

is 70 feet long and was driven in fluorspar for a distance of 30 feet.
DEPOSITS IN THOMAS RANGE DISTRICT, JTJAB COUNTY 35

Dolomite, silicified where stippled

<»> 

Fluorspar

EXPLANATION

Contact, dashed where approximately located 

Limit of outcrop

^

Strike and dip ot beds

Fault, showing dip. bearing, 

and plunge ot slickensides

FIGURE 13. Map and section of the Eagle Kock property, Juab County, Utah.

The other crosscut extends west to the edge of the body and is 30 feet 

long. A shaft inclined at 60° has been sunk from the surface to the 

lower adit level. The glory hole is an elongate, northwest-trending
36 FLUORSPAR DEPOSITS OF UTAH

cut that is 60 feet long and 40 feet wide at the surface. An inaccessible 

vertical shaft extends from the bottom of the glory hole for an estimated 40 feet in fluorspar. Several small prospect pits have been dug 

south of the opencut on extensions of the fluorspar body.

The Floride deposit is a pipelike replacement body (pi. 7A) in 

dolomite near a northeast-trending fault that places the older quartzite 

against the younger dolomite. The dolomite is a dense, dark-gray to 

black, thick-bedded rock that strikes N. 32b-38° E. and dips 26°-32° 

NW. The quartzite strikes N. 30° E. and dips about 29° NW.

The major structure in the vicinity of the Floride mine is a normal 

fault that strikes N. 85° E., dips 55°-60° SE., and has a vertical displacement of about 200 feet. The quartzite was not fractured during 

the faulting, whereas a breccia zone as much as 10 feet wide occurs in 

the dolomite at the contact with the quartzite.

Two sets of fractures were observed in the lower adit. The strongest set strikes N. 30°-35° W. and dips T0°-90° NE. Commonly the 

second set, consisting of northeast-trending fractures, is filled by white 

coarsely crystalline caleite veins, as much as 1 foot thick. The fractures generally are not mineralized with fluorite and commonly contain 

caverns as wide as 1 foot. In the upper adit level a small fault forms 

the contact between altered and unaltered dolomite. The altered 

dolomite contains abundant caleite and limonite stains, and can be 

traced to the glory hole where the zone disappears.

The fluorspar body is irregular in outline and has a maximum length 

of 100 feet and an average width of 40 feet. The footwall of the body 

dips southeast approximately parallel to the fault; the hanging wall is 

essentially vertical. The irregular shape of the deposit, the relict 

bedding in the fluorspar adjacent to the dolomite, and the veinlike 

stringers of fluorspar along bedding planes in the dolomite indicate 

that the fluorspar is a replacement body in the dolomite. Caleite occurs as thin stringers and as pockets in the dolomite adjacent to the

fluorspar and makes up 50 percent of tllG TOCk 111 801116 plaCBS,

The fluorspar is extremely variable in color and composition, ranging from a dark-purple, highly siliceous material to soft white powdery

material that is 95 percent CaF2 . For the most part, it is fine-grained,

 white to pale purple and in carload lots assays 85 percent CaF2 . Son'16 

of the dark-purple highly siliceous material contains finely crystalline

carnotite as radiated aggregates and as thin veinlets filling fractures,

ExpOSUreS Of fluorspar-Cemented breccia are numerous in trenches

near tlxe -workings and in gullies to tne SOlltll. Here, the dolomite shows no displacement, although some of the fluorspar-bearing zones

are aS niUCh as 30 feet long. Evidently zones of shearing rather than

simple faults were mineralized.
DEPOSITS IN THOMAS RANGE DISTRICT, JUAB COUNTY 37 

FLUORINE (FLUERIN) QUEEN PROPERTY

The Fluorine (Fluerin) Queen property is about 1,800 feet above

 the valley bottom to the east, in the southeast part of T. 12 S., R. 12 W.,

 Salt Lake principal meridian. Two large fluorspar pipes, the west 

pipe and east pipe, about 100 feet below and on either side of the crest

 of Spors Mountain, are reached by a steep mountain road along the 

east face of the mountain (fig. 11). The Fluorine (Fluerin) Queen

 claim was located in March 1948 by W. E. Black and F. B. Chesley of 

Delta, Utah. About 6,770 tons of fluorspar were mined at this property

 from 1948 to 1950.

The west pipe (fig. 14) has been worked from an irregular open 

pit, 105 feet long and about 25 feet wide. The pit was from 28 to 45 

feet deep in September 1950 but was not being worked. The east pipe 

Jhas been stripped of overburden, and a cut 80 feet by 60 feet has been 

:made. The pit is 15 feet deep on the west side.

Geology by M. H. Staatz and H. L. Bauer.Jr., September 1950

FIQDKB 14. Outlines of fluorspar pipes, Fluorine Queen property, Juab County, Utah.
38 FLUORSPAR DEPOSITS OF UTAH

Both fluorspar deposits are in dark-gray dolomite. The west pipe 

is irregular in shape, and walls dip steeply. The contact of the fluorspar and dolomite is sharp; the dolomite is not altered. This fluorspar body has a maximum exposed length of 105 feet and a maximum 

width of 80 feet. The east pipe is more regular in shape and is oval in 

plan. It has a maximum exposed length of 175 feet and a maximum 

width of 103 feet. Not enough development work has been done to 

determine the downward extension of this body.

The fluorite in both deposits is white to dark purple, soft, and 

friable. Carnotite is visible in a streak of hard fluorite, about 40 feet 

long and 1 foot wide, in the middle of the west pipe..

FLUORINE QUEEN NO. 4 CLAIM

The Fluorine Queen No. 4 claim (fig. 11) is on the southern slope of 

a southwestward-trending ridge that rises about 1,200 feet above the 

valley floor. The claim is on the west slope of Spors Mountain in 

the southeast part of T. 12 S., E. 12 W., Salt Lake principal meridian. 

It is reached from the west pit on the Fluorine Queen claim by means 

of a rough trail. The Fluorine Queen No. 4 claim was located in 

March 1948 by W. E. Black and F. B. Chesley of Delta, Utah.

A dense dark-gray cherty dolomite crops out in a prominent cliff, 

strikes N. 36° E., and dips 35° NW. Small fragments of a highly altered rhyolite porphyry, stained deep red by iron oxide, were observed 

in the fluorspar. The rhyolite porphyry contains rounded phenocrysts 

of smoky quartz in a fine-grained groundmass of limonite-stained clay.

Fluorspar occurs in a northwest-trending, elongate body that is 

about 90 feet long and averages 20 feet wide (fig. 15). The deposit 

has been prospected by four small pits, the deepest of which is about 

8 feet. The body underlies a depression as much as 6 feet below the 

outcrops of the adjacent dolomite. The fluorite is white to pale violet. 

The matrix of the fluorite contains abundant limy material.

HARRISITE PROPERTY

The Harrisite property (fig, 11) is near the base of some low hills

at the southern end of Spors Mountain in sec. 10, T. 13 S., B. 12 W.,

Salt Lake principal meridian. The Harrisite group of claims was

located on May 10, 1949, by E. D. Harris, E. T. Harris, Rex Harris,

and Mark Harris of Delta, Utah, No fluorspar had been produced

from this property by September 1250, but according to the Harris

brothers the deposit contains 60 to 65 percent CaFa .

TllO main WOrMngS (pi. 8) are two bulldaozer trenches (trenches

No. 1 and 2) and a narrow hand-dug trench (trench No, 3), Trench 

No. 1, about 70 feet long and 15 feet wide, is in dolomite on the hillside. 

Trench No. 2, which measures 220 by 30 feet, partly exposes a fluor-
DEPOSITS IN THOMAS RANGE DISTRICT, JUAB COUNTY 39

EXPLANATION

Fluorspar

Approximate contact

Strike and dip of beds

Prospect pit

60 Feet

Geology by V. R. Wilmarth and H. L. Bauer, Jr., September 1950

FIGURE 15'. Outline of fluorspar pipe, Fluorine Queen No. 4 property, Juab County,

Utah.

spar body in the wash. Several small pits have been sunk in this 

trench. Trench No. 3, 40 feet long and 5 feet wide, has a maximum 

depth of 9 feet and exposes a small fluorspar vein at the fault contact 

of dolomite and altered rhyolite porphyry.

The rocks on the Harrisite property consist of several much-faulted 

dolomite units, conglomerate of the Lake Bonneville beds, basalt, and 

a small body of altered rhyolite porphyry. The dolomite strikes 

N. 6° W.-N. 29° E. and dips 25°^2° W.

The southwestern part of the property is underlain by basalt. 

This rock is dark gray on fresh surfaces and deep brown on 

weathered surfaces. It consists of about 10 percent of dark-green, 

euhedral phenocrysts of pyroxene, as much as an eighth of an inch 

long, in a fine-grained aphanitic groundmass of plagioclase crystals, 

a little magnetite, and some glassy material. The basalt may be either 

a flow or an intrusive body and is presumed to be related to basaltic 

rocks south and east of Spors Mountain.

Basalt, which is now altered almost entirely to clay, crops out on 

the southern side of trench No. 3. The altered material retains its 

original texture. The altered basalt is cut by a small fault and many 

small parallel shears.

Six northeast-striking faults and one east-striking fault were 

mapped (pi. 8). Some small fluorite stringers exposed in the main 

wash may have formed on another fault parallel to the east-trending
40 FLUORSPAR DEPOSITS OF UTAH

fault. The easternmost fault (pi. 8) offsets two recognizable units of 

the dolomite 64 feet horizontally. A second northeast-trending fault, 

dipping 74° SE., is exposed in trench No. 3 adjacent to altered basalt; 

it probably continues to the northeast. A third northeast-trending 

fault is inferred to be along the bottom of the wash, because of the 

omission of a considerable part of one dolomite bed in the southern 

part of the area. An outcrop of brecciated and silicified dolomite 

in the northeastern edge of the valley suggests faulting. The fourth 

fault is a strike fault that brings up units'exposed in the eastern part 

of the map area. The displacement is at least several hundred feet. 

The fifth and sixth faults branch from this fault and appear to be 

later. ;

The fluorspar deposits at the Harrisite property consist of a thin 

veinlike body in trench No. 3 and large irregular bodies in trench No. 

2. Powdery, white to dark-purple fluorite occurs along shears or 

small faults in dolomite and altered basalt. The thin, irregular body 

in trench No. 3 dips about 74° E., parallel to the dip of the adjacent 

fault. The attitude of the larger deposits in trench No. 2 is not definitely known and on plate 8 is shown as dipping vertically parallel 

to the adjacent fault. The deposits consist mainly of fluorite but 

contain some clay. Dolomite fragments are found in some places, 

 especially in the fluorspar of trench No. 2. No uranium minerals are 

visible in the fluorite, but in trench No. 3 carnotite was noted along 

shear planes in the adjoining altered basalt.

The vein in trench No. 3 is 6 inches to 3 feet wide and is exposed 

for 20 feet along the trench. The irregular bodies in trench No. 2 

;are very poorly exposed. They cover an area at least 75 feet long, 

with a maximum width of 25 feet. Several stringers less than 1.5 feet 

wide extend about 100 feet to the west from the main body.

LOST SHEEP PROPEBTY

The Lost Sheep property (fig, 11) is on the east side of Spors 

Mountain in the central part of T. 12 §,, R, 12 w., Salt Lake principal

meridian. The mine is on tne sicle of a. nill several hundred, feet above

the valley bottom to the east, and is reached by about one-quarter

mile of private road from tne nortk enol of tne haulage road On the

east side of Spors Mountain. The Lost Sheep group of claims'was

Staked May 1O, 1948, by A-lbert Willden and. Earl "Willden of Delta,

Utah. 

Two fluorspar pipes, the main pipe and the west pipe, are on tiie

Lost Sheep property. The main pipe is mined from an open pit 140 

feet long and 60 feet wide (fig. 16). It is 54 feet deep on the west 

side. About 6,400 tons of fluorspar had been produced from this pipe 

through August 1950. The west pipe is about 800 feet southwest of 

the main pipe and crops out several hundred feet above it. An adit,
DEPOSITS IN THOMAS RANGE DISTRICT, JUAB COUNTY 41

MAIN PIPE EXPLANATION

WEST PIPE

Approximately 800 feet 

southwest of the main pipe

Fluorite ore body

Contact, dashed where 

approximately located

Strike and dip of beds 

Opencut

80 Feet 

_J

Contour interval 10 feet 

Datum assumed

Dump

Geology by M. H. Staatz and H. L. Bauer, Jr., September 1950

FIGURE 16. Outlines of fluorspar pipes, Lost Sheep property, Juab County, Utah.

about 200 yards southwest of the main pipe, was driven jointly by 

T. A. Claridge and the Willden brothers. It is about 500 feet long 

and intersects the Blowout deposit 240 feet below the surface. A 

branch crosscut, started about 200 feet from the portal, is expected 

to reach the west pipe on the Lost Sheep property at a point about 

200 feet below the surface.

The two fluorspar pipes on the Lost Sheep property are roughly 

oval in plan (fig. 16). The main pipe is 160 feet long, about 65 feet 

wide, and at least 54 feet deep; the walls dip steeply and may con-
42 FLUORSPAR DEPOSITS OF UTAH

verge at depth. The west pipe is 37 feet long and about 10 feet wide; 

the depth of the deposit is not known. The main pipe is entirely in 

compact, light-gray dolomite that contains about 2 percent of chert. 

The dolomite is brecciated near the deposit in some places. The beds 

strike N. 45°-50° E. and dip 42°-44° NW.

A dike or a large plug of intrusive breccia several hundred yards 

long is exposed in small pits and road cuts and in the adit about 400 

feet southwest of the main pipe. The adit starts in intrusive breccia, 

consisting of fragments of rhyolite porphyry in a matrix of similar 

material, and continues for 81 feet in this rock. The fragments of 

rhyolite porphyry commonly are altered, but fresh surfaces show 

quartz phenocrysts and a few unaltered orthoclase crystals in a white 

aphanitic groundmass. A 1%-inch vein of fluorite is exposed along 

the top of the adit near the portal.

Both pipes consist of soft, white toNdeep-purple, pulverulent fluorspar. Carload lots of selected fluorspar are reported to contain as 

much as 95 percent fluorite. No uranium minerals are visible.

LUCKY LOUIE PROPERTY

The Lucky Louie property (fig. 11) is on the southern end of the 

low hills that form the south end of Spors Mountain. It is in the 

NWi/4 sec. 10, T. 13 S., E. 12 W., Salt Lake principal meridian. The 

property is connected to the haulage road along the west side of the 

mountain by a narrow dirt road, several hundred yards long. The 

property was staked by James Quigley, H. E. Carlson, E. H. Snell, 

and Hyram Schmidt of Eureka, Utah. Little prospecting has been 

undertaken, though two widely separated bulldozer trenches have 

been made. One trench exposed fluorite pebbles in a conglomerate 

that formed in Lake Bonneville. The second trench exposed fluorspar, but the size and shape of the deposit are not known. The minimum dimensions of this body appear to be 10 by 20 feet, but further

exploration might expose a body many times this size. James Quigley

reports (personal communication) that a sample of this fluorspar

contained 83 percent CaF2 .

NONELLA NO. 1 CLAIM

The Nonella No. 1 claim is on the eastern flank of Spors Mountain

at an altitude of about 5,500 feet (fig. 11). It is in the south-central

part of T. 12 S., JR. 12 W., Salt Lake principal meridian. The property is 500 feet above the haulage road and is connected to it by a steep 

trail. The Nonella No. 1 claim was located on April 20, 1948 by

Nona Chesley ana Ella Black of, JDelta, Utah, Little aerelopment

work has been done on this property. A pit 15 feet long, 8 feet wide, 

and 10 feet deep has been dug on a fluorspar body in dark-gray
DEPOSITS IN THOMAS RANGE DISTRICT, JUAB COUNTY 43

dolomite that strikes N. 35° E. and dips 34° NW. The fluorspar 

body is covered almost entirely by talus made up of dolomite and 

chert boulders. White to pale-purple, fine-grained fluorite is exposed 

in the pit. Locally the fluorspar contains many thin stringers of opal. 

Fragments of altered rhyolite porphyry were found on the dump, 

but none was observed in place. The altered rhyolite porphyry is 

deep red and contains abundant phenocrysts of smoky quartz in an 

aphanitic groundmass of clayey, calcareous, limonitic material.

OVERSIGHT NO. 4 PROPERTY

The Oversight No. 4 property, the northernmost fluorspar deposit 

(fig. 11) in Spors Mountain, is in the southwest part of T. 12 S., 

K. 12 W., Salt Lake principal meridian. It is near the crest of a 

jagged hill that rises 800 feet above the valley floor. A rough dirt 

road, 1 mile long, leads from the main haulage road to the compressor 

house, and a trail leads southward to the mine workings. The claim 

was located in 1949 by Fred Staats, Frank Lowder, and Steve Stephenson.

The Oversight No. 4 property is developed by a 20-foot opencut 

and several prospect pits and bulldozer trenches. The opencut is on 

a vertical fluorspar pipe about 20 feet in diameter in a dense, finegrained, black dolomite that strikes N. 34° E. and dips 32° NW. The 

ore consists of a boxwork of brownish fluorspar.

THURSDAY NO. 3 PROPERTY

The Thursday No. 3 property (fig. 11) is in the south-central part 

of T. 12 S., K. 12 W., Salt Lake principal meridian. An 8-mile dirt 

road along the western edge of Spors Mountain connects this mine to 

the main haulage route to Delta, Utah. The Thursday No. 3 claim 

was located September 5, 1948, by W. L. Hamblin, G. D. Hamblin, 

and A. W. Hamblin of Kaysville, Utah. Production records are not 

complete, although it was reported that about 100 tons of fluorspar 

has been produced from this claim. Mining was not in progress in 

September 1950.

The workings on the Thursday No. 3 property (fig. 17) consist of 

two adits, four opencuts, and several prospect pits. The main adit 

was driven S. 43° E. along a fault for 175 feet. The deposit at the 

main adit is developed on the surface by three opencuts, from which 

most of the fluorspar has been mined. The second adit, not shown 

on figure 17, was driven N. 80° W. for 300 feet from the eastern side 

 of the hill, about 150 feet below the main adit level. The second 

adit intersects an 8- to 12-inch fluorspar vein at the face.

The fluorspar occurs as thin veins and replacement bodies in dolomite (fig. 17) that strikes N. 42° E. and dips 30°-34°. NW. The
44 FLUORSPAR DEPOSITS OF UTAH

PLAN OF 

UNDERGROUND WORKINGS

.Altered rhyolite prophyry 

MAP SECTION 1:

Fluorspar

Approximate contact

,30

A Strike and dip of beds 

-560O

5560

Fault, showing dip: dashed 

where approximately located

Opencut

Underground workings

5480 Dump

FIGURE 17. Maps and section, Thursday No. 3 property, Juab County, Utah.
SILVER ,QUEEN DEPOSIT, TOOELE COUNTY 45

dolomite is intruded by a dike of highly altered, reddish-brown 

rhyolite porphyry. This rock contains orthoclase phenocrysts, altered 

to a greenish clay, in an aphanitic groundmass of quartz, feldspar, 

and dark-purple fluorite. In some places the rhyolite porphyry has 

a purplish hue because of the abundance of the fluorite. The dike 

trends northeast and was traced.for several hundred feet along strike.

The major fault in the vicinity of the mine strikes N. 42°-60° W. 

and dips 72°-87° NE. It is exposed throughout the main adit and 

in the largest opencut, southeast of the adit portal. The amount and 

direction of movement on the fault could not be determined, though 

the displacement appears to be small. The dolomite has been brecciated on the footwall side of the fault.

Two fluorspar bodies are exposed in the Thursday mine workings. 

The largest, in the footwall of the fault, has a maximum thickness of 

14 feet in the opencuts and 6 feet on the main adit level, 65 feet below 

the surface. This body has a minimum length of about 240 feet. A 

second fluorspar vein, exposed in a prospect pit about 50 feet east 

of the largest opencut, has a maximum; length of 60 feet and a maximum width of 10 feet. The fluorspar in both bodies is white to pale 

purple, fine-grained and sugary, and locally contains small pockets 

of coarsely crystalline fluorite. Narrow veins of white crystalline 

calcite are numerous at the contact of the dolomite and the fluorspar.

SILVER QUEEN DEPOSIT, TOOELE COUNTY

By J. F. Smith, Jr., and A. H. Wadsworth, Jr.

The Silver Queen fluorspar deposit, Tooele County, is about 21 miles 

south of Clive, a station on the Western Pacific Railroad, which is 48 

miles east of Wendover, Utah, on U. S. Highways 40 and 50. About 

1,200 tons of high-grade fluorspar was mined at the Silver Queen 

deposit, also known as the Wildcat mine, between 1918 and 1924. In 

1938 a few tons of fluorspar was mined.

The deposit was described by Heikes (1922), Buranek (1942), and 

Burchard (1933, p. 21). Buranek (1942, p. 21) reports that a lamtprophyre dike occurs close to the fluorspar deposits. In his discussion of 

the age of the limestone in which the fluorspar occurs, Buranek (1942, 

p. 21) quotes a private report by R. E. Marsell, who interpreted the 

fossils to be of Carboniferous age. According to Burchard (1933, 

p. 21), at various places over a 90-acre tract surrounding the Silver 

Queen deposit, veins along faults of small displacement contain fluorite, barite, pyrite, chalcopyrite, and traces of gold and silver.

The fluorite veins at the Silver Queen deposit are on a limestone 

hogback trending north-south and on a low, flat limestone hill about

286657 54 4
46 FLUORSPAR DEPOSITS OF UTAH

800 feet east of the hogback (fig. 18). The two hills rise above the 

deposits of former.Lake Bonneville. On the hogback the limeston'e 

beds in general strike north to northwest and dip 20°^50° W. On 

the low hill they strike nearly east and dip 30° S.* The reason-for 

this difference in strike in the two areas was not determined during 

the short time spent on the property, but it may be the result of 

faulting.

The fluorite occurs as well-formed cubes that range from almost 

colorless to blue and green. Green copper staining and crystals of 

white witherite arid dolomite are associated with the fluorite in the 

veins. A thin streak of reddish opaline material along the east side 

of the vein in the southern cut on the hogback was the only siliceous 

material observed.

The fluorite veins trend N. 75°-80° E. and N. 5°-35° E. Along the 

fissures the fluorite occurs in pockets, 5 to 15 feet long and 2 inches to 

5 feet thick. The northward-trending vein on the hogback has a 

maximum thickness of 2 feet, pinches to 2 inches in places, and is not 

continuously mineralized with fluorite for the entire length indicated 

on the map (fig. 18).

Most of the fluorite has been removed from the trenches shown on 

the eastern hill, although small pockets of fluorite were left on the

hanging walls of small faults.

The southernmost trenches that cross the eastern hill appear to be 

along a main fracture that trends N. 80° E. and dips 50° N. On the 

hogback a mineralized fault with this trend has a throw of 10 to 15 

feet. The area between these outcrops is covered by the lake deposits, 

and a caved shaft about 10 feet deep along the projected trench, contains only lake sediments.

A. drift at a. depth of 40 feet in the shaft on the east side of the low

hill has been driven S. 35° W. along a 2-foot Yein Of fluOrite OH the 

east wall. This vein is traceable for about 100 feet, although it is

pockety in places and ranges in thickness from a few inches to 2 feet.

At the same depth a short drift trending S. 80° W. has cut a few small

pockets of fluorite, At the bottom of tk shaft, about 80 feet deep,

small pockets of fluorite remain along the hanging wall of a fault

striking N. 45° E. and dipping 55° NW- A short stope has been 

Worked along mis mineralized zone.

The northernmost inclined shaft on the hogback cuts a fluorite vein

at tiie, opening tout £ollows another vein downward. Xhe latter vein

Carries mostly dolomite and witherite. The lower inclined sWt to 

the southeast did not cut the northward-trending vein exposed higher

on the hogback.
200 400 Feet

r

PIGOBB 18. Geologic sketch map of Silver Queen area, T
48 FLUORSPAR' DEPOSITS OF UTAH

On the hogback the fluorite does not occur above a quartzite bed 

that overlies the limestone. Several prospects in another hill several 

hundred feet west of the hogback failed to show any fluorite.

All the fluorite observed is in small pockets along the.walls of the 

old workings and would have to be selectively mined. The alinement of the veins on the two hills suggests that they may continue 

across the intervening sand-coyered area. Trenching is recommended 

for prospecting between the exposures on the hills; the thickness of 

the overburden, however, is unknown.

RESOURCES AND POSSIBLE DEVELOPMENT

By W. R. Thurston

The possibilities of mining fluorspar in Utah have not attracted 

wide attention until recently. The interest in the metallic ores of 

the State has overshadowed the less-known nonmetallic minerals, 

and it is doubtful that many prospectors have been aware of either 

the value of fluorspar or the means of recognizing it. Only one deposit, the Silver Queen mine, was found worthy of mining before 

1920, but since 1935 minable deposits have been located in widely 

separated parts of the State.

The critical need for fluorspar in World War II aroused interest 

in fluorspar mining and showed the need for intensive search for new 

deposits. War-born shortages of men and materials, however, made 

thorough study and exploration impossible. The resultf is that known 

deposits were greatly depleted and few new deposits have been found.

The known reserves of fluorspar in. Utah total about 450,000 tons 

of material having a minimum of 40 percent of CaF2. When compared with fluorspar deposits elsewhere in the Nation, most of; the 

deposits of fluorspar in Utah, appear small, but in part this is due

to lack of adequate exploration and study, No estimate is made of

reserves that might be disclosed by future geologic or exploratory

"work. ' At the present stage of geologic knowledge the Thomas nange and

the Indian Peak Range appear to hold the greatest promise for disCOVerieS Of new fluorspar deposits. Additional geologic mapping inay

ITOEl 111016 CtorlY thO Structural control of the known deposits and

locate similar structures favorable for exploration. I he depCSllS 

in the Thomas Range district are in general larger than those elsewhere in Utah. The reserves in this district were estimated in 1950 

by StaatZl tO toe about 627000 tons of indicated fluorspar and about

300,000 tons of inferred fluorspar. The known reserves in the Indian
RESOURCES AND POSSIBLE DEVELOPMENT 49

Peak Kange, at the Cougar Spar, Blue Bell, and JB mines, amount to 

about 50,000 tons of fluorspar containing approximately 40 percent 

of CaF2 . The crude fluorspar, however, contains abundant quartz 

and brecciated country rock and as a consequence is very siliceous. 

Simple gravity methods of concentration have not been entirely 

satisfactory for reducing the silica content, but the use of flotation 

methods of beneficiation probably would result in the recovery of 

high-grade fluorspar concentrates.

The Monarch (Staats) area of Beaver County can be expected to 

produce fluorspar for some time under present economic conditions. 

Washing equipment that the operator has installed at Lund, Utah, 

should make it profitable to mine and beneficiate the more clayey 

fluorspar that has been of submarginal grade in the past. Cross-1 

faulted parts of the contact between the rhyolite porphyry and limestone should be sought and explored. Any new deposits probably 

will be high in fluorspar content, relatively low in silica content, and 

small, much like the known deposits.

The Thomas Eange district in Juab County has many exposures 

of fluorspar, and 12 deposits have been mined successfully (table 2). 

Further study of the area may reveal the structural controls and guide 

the exploration for other fluorspar deposits. Many favorable localities remain for the discovery of additional fluorspar deposits in the 

district.

The Star district in Beaver County is not so favorable geologically 

as the Thomas Eange district. Undoubtedly most of the known 

pockets of fluorspar have been mined, and underground exploration 

for additional deposits of such small size is not warranted. The recovery of byproduct fluorspar from the mining of metal ores in the 

Star district is dependent on the production of those ores.

The Silver Queen (Wildcat) area is even less favorable for further 

exploration. Since the period 1918 to 1924, when more than 1,000 

tons of fluorspar was produced at the Silver Queen mine, no important bodies of fluorspar have been found. Additional fluorspar deposits may exist beneath the overburden, but unless they are larger 

than those mined heretofore they would be too difficult and costly 

to find.

Fluorite has been reported from other places in Utah. Whether 

any of these localities will become important producers of fluorspar 

is questionable, but in the absence of more nearly complete data some, 

at least, should be examined critically. The occurrences are listed 

in table 3 and shown in figure 1.
TABLE 3. Minor occurrences of fluorite 

County Name of cwirrence Locality data Fluorite occurrence 

BeaverBeaver. -...._

BeaverGrand..

Grand. 

Iron...

JuabJuab.

Juab.

Millard. 

Piute...

Cupric Mtne Co. tungsten 

deposit, SaB Francisco 

district.

Qranite district, Bismuth 

mine' and Big Pass and 

2 R's prospects.

Mystery and Sniffer claims, 

Indian Creek.

Ryan Creek scheelite prospect of the late Joseph 

Qutnn of Gnnd Junction, 

Colo.

Blue Spar propect, W. B.

Knight, Jr. 

Gold Sprirxgsdistrict...--...

Johnson IPeak or Trout 

Creek'dLstiil

Fish Springs district..._..

West Tin.tic district, "88" 

mine.

Rain Boxv mine, Brice

Prisby. 

Ohio district, Bully Boy

and \Ve~t>ster mines.

On "West side of San Francisco 

Mts., 16 miles west of Milford.

Mineral Range east of Milford-...

Nortt side of Indian Canyon, sec.

28, T. 27 S., R. 6 W., Marysvale

region. 

InT. 22 S., R. 25 E.; at altitude of

5,200 ft, 1 mile east of the junctioti of Ryan and Cow Creeks,

on Ryan Creek.

Near Grand Junction, Colo..-_-_. 

17 miles northwest of Modena.....

In -Deep Creek Range, 20 miles 

so iath of Callao; on north side 

of Trout Creek near base of 

range.

T. 11 S., R. 14 W.; northwest end 

of Fish Springs Range, about 1 

mile north of Joseph Tunnel and 

ea,st of magnesite prospects.

Abovut 21 miles southwest of 

Eiareka; south margin of Sheeprock Mts.

In sec. 30, T. 25 S., R. 6 W., about 

1 $- £ miles northeast of Cove-Fort.

Ab»-ut T. 27S., R. 3 W.; in Tushar 

Range, Marysvale region.

Fluorite is one of the mino

minerals developed in the 

bearing sulflde ore body a

tact between sedimentary 

quartz monzonite.

Fluorite is one of the mino

minerals developed in lime

the contact with granite; b

ite, molybdenite, and sch

among the associated mine

Fluorite, associated with 

occurs in Tertiary volcani

Fault breccia between sand

granite, cemented, by fluo

ing vein material; associ

erals are carbonates and b

traces of galene, sphale

scheelite.

Not described..-.. ______

Traces of fluorite common i

trict; most conspicuous at 

on summit of Bmll Hill.

Fluorite is conspicuous gan

eral in dump at a prospect s

in search of sphalerite ore.

Qreen fluorite in limestone; v

. 8 in. wide and 12 ft long.

Clear to purple fluorite is 

with quartz, barite, and g

Not described ____-.

Fluorite is a minor mineral i

vein filling a fault in qua

lava; associated, minerals 

bonates and barite.
Piute. . .

Tooele ........

Tooele ____

Tooele. .......

Weber. 

Weber. 

(Farmer John) mine.

B. Freedom and Prospector 

claims.

Park City district, Woodside mine and Silver King 

mine.

38 claim (Cannon prospect) .

Desert claim.

ver King and Copper Jack 

prospects.

Gold Hill district, Gold

Bond claim. 

Weber district...... .

26 and 27, T. 26 S., R. 4 W.

B. Sec. 4, T. 27 S., R. 3 W. 

Both in Antelope Range, Marysvale region.

In Woodside Gulch, T. 2 S., R.

4E.

up Long Trail Gulch from 

Ophir. 

T. 10 S., R. 12 W., Dugway Mts..

claims; approximately in T. 9 

S., R. 6 W.

In T. 8 S., R. 18 W.; in Lucy L

Gulch about 1}$ miles south of 

Gold Hill. 

In Cold Water Canyon, 2 miles

east of Ogden.

A. White to purple fluorite occu

fillings in steeply dipping fi

and breccia zones

B. The fluorite forms blebs and l

in or adjacent to dense quartz 

in quartz monzonite.

Associated with uraniferous ma

at both localities.

Fluorite is a conspicuous gangue 

eral in ore from the Carey incl

the Woodside mine and is asso

with oxidized replacement ore 

Silver King mine.

Fluorite is a gangue mineral of s

ore in limestone.

Quartz veins in quartzite co

some fluorite.

Fluorite in a vein with quartz, h

tite, and locally galena and 

copyrite.

Uraniferous sulfide-fluorite-q

veins in granite.

Fluorite associated with le

quartz and lead carbonate, c

in quartzite.

Small amounts of purple and 

fluorite are associated with danb

in a vein in quartz monzonite.

Fluorite reported to occur with b

quartz, and copper minerals 

vein between quartzite and 

stone.

Narrow fluorite veins in gneiss 

pegmatite of pre-Cambrian age
52 . FLUORSPAR DEPOSITS ,OF UTAH 

LITERATURE CITED

Boutwell, J. M., 1913, Ore deposits of the Park City district, Utah: U. S. Geol.

Survey Prof. Paper 77. 

Buranek, A. M., 1942, The fluorspar deposits of the Wild Cat Mountains, Tooele

County, Utah: Utah Dept. Publicity and Industrial Devel., Circ. 5, p. 20-28.

 1948, Fluorite in Utah: Utah Dept. Publicity and Industrial Devel.,

Circ. 36,25 p. 

Burchard, E. F., 1933, Fluorspar deposits in western United States: Am. Inst.

Min. Met. Eng. Tech. Pub. 500, p. 3-25. 

Butler, B. S., 1913, Geology and ore deposits of the San Francisco and adjacent

districts, Utah: U. S. Geol. Survey Prof. Paper 80. 

Butler, B. S., Loughlin, G. F., Heikes, V. C., and others, 1920, The ore deposits

of Utah: U. S. Geol. Survey Prof. Paper 111. 

Crawford, A. L., and Buranek, A. M., 1945, Tungsten deposits of the Mineral

Range, Beaver County, Utah: Utah University Bull., v. 35, p. 29, 46. 

Dane, 0. H., 1935, Geology of the Salt Valley anticline and adjacent areas,

Grand County, Utah: U. S. Geol. Survey Bull. 863. 

Davis, H. W., 1950, Fluorspar and cryolite: U. S. Bur. Mines Minerals Yearbook,

1948, p. 589.

Everett, F. D., and Wilson, S. R., 1950, Investigation of the J. B. fluorite deposit, Beaver County, Utah: U. S. Bur. Mines Rept. Inv. 4726, 11 p.

 1951, Investigation of the Cougar Spar fluorspar deposit, Beaver County,

Utah: U. S. Bur. Mines Rept. Inv. 4820,12 p. 

Fitch, G. A., Quigley, James, and Barker, C. S., 1949, Utah's new mining district:

Eng. and Min. Jour., v. 150, p. 63-66. 

Gilluly, James, 1932, Ore deposits of Stockton and Fairfield quadrangles, Utah:

U. S. Geol. Survey Prof. Paper 173. 

Heikes, V. C., 1922, A fluorspar deposit in Utah: Mineral Resources U. S.,

1921, pt. 2, p. 48-49. 

Hobbs, S. W., 1944, Tungsten deposits in Beaver County, Utah: U. S. Geol.

Survey Bull. 945-D. 

Marsh, J. A., and Everett, F, D,, 1945, A new domestic source of fluorspar in

Utah: Eng. and Min. Jour., v. 146, p. 98-100. 

Muessig, Siegfried, 1951, Eocene volcanism in central Utah: Science, v. 114,

p. 234. 

Nolan, T. B., 1935, The Gold Hill mining district, Utah: U. S. Geol. Survey Prof.

Paper 177.

, B. P., 1942, Mineralization in the West Tintic mining district, Utah:

Geol. Soc. America Bull., v. 53, p. 285.
INDEX

Page

Aragonite_______ ________._ 5 

Autunite.. ...... 6,17

Batite..._____.___.__._____. 6,45

Calcite..........-.-.-..---..-.. ........... 5

Carbonate minerals__ _____.. . 6 

Carnotite..... ..-. --........... 5,28,30,38,40

Chalcedony...._____________ 4,8

Ohalcopyrite_ .............___... 5,22,23,45

Clays.......... . . . - 6,25,28

Deposits, classification.....____ _ 4

distribution________________ 2

Dolomite......._..........._.......... 5,28,46

Elephant limestone... 22

Fluorite, mineralogy__.___.__.. 4 

minor occurrences_________ .. 50-51

Galena.......__....___.____._ 5,22,23

Gold and silver__________ 6,45

Indian Peak Range, geology, 

order of mineralization...

Magnetite.. ...... . . ......... 5,22

Mines, prospects, and claims, Bell Hill.... 26,29-30

Blowout property_.______ 26,30-32 

Blue Bell 10-12

Brown Thrush___...___........ 21

Cabin.............................. 21-22

Cougar Spar_____________ 8-10 

DellNos. 1,2, and 3...... .. .- 26,32

Dell No. 6 property-__.....____... 26,33

Dugout..... ...._........ ..... 16

Eagle Rock......._._.__.___._ 33-34

Floride 26,34-36

Fluorine Ledge........................... 21,22

Fluorine (Fluerin) Queen..._....... 26,37-38

Fluorine Queen No. 4.._____ ... 38,39 

Harrisite. 38-40

Hub.... . . 21,22

JB. ........ . - 13-14

Lady Bryan________________ 21,22 

Lost Sheep (Indian Peak Range)... 16 

Lost Sheep (Thomas Range) _____ 26,40-42 

Lucky Boy No. 1_ _____ 21 

Lucky Boy No. 2_____________ 21,22 

Lucky Louie_______________ 42 

Manassa.... . .._....... . 21,22,23

Monarch......................... 1,3,4,5,16-19

MonteCristo............._._...... 21,22,23

Moscow.________________ 21,22,23

Page 

Mines Continued

Nonella.No. 1............................ 42-43

Noonday_________________ 12,13 

Original Spor. See Floride mine. 

Oversight No. 4_..__...-...-.-...-.. 43 

Quartzite ........................ 21,23

Roberts and Skougard. See Monarch.

Silver Queen__...._........._ 1,3,4,46-48

Silver King..._......_......._..... 4

Skougard. See Monarch.

Staats. See Monarch.

Thursday No. 3.- ..... 26,43-45

Utah............... 14-16

Virginia and North Virginia Extension 21,

23-24 

Wildcat. See Silver Queen.

Orthoclase.

Pine Grove mining district___.. 16 

Production.___________ 1,3 

Prospecting, suggestions, Thomas Range district . 28-29 

Pyrite .............. 6,22,23,45

Quartz.. 4,6,8,12,14,15,16,21,28

Red Warrior limestone.... .. 21,22

Reserves, Monarch (Staats) area... 49 

Thomas Range district__.__ .. 48 

State of Utah............... . . ... 1-2

Resources.______________.. 48-49 

Rhodochrosite.__________________ 5,23

Silica minerals_._____..... . 4-6

Silicates...______.. . 5 

Specularite.____________ 6 

Sphalerite 6,22,23

Spors Mountain, location....... . 24

Star district, general description___ 19-24

fluorspar localities_... . 20,21

Sulfides........._.......__............ 5,21,22

Thomas Range district, assays_ 28 

fluorspar production_.. 26-26 

general geology. 26-28

Uranium_________..... 28

Uranium minerals_____ .. ... 6,34

Uranophane_____ ... 6,17

Washington metal-mining district_.. 6 

Witherite........................... ... 5,46

o

53