Reconnaissance Study 

of Uranium Deposits 

in Arizona

GEOLOGICAL SUR.VEY BULLETIN 114 7-A

Prepared on behalf of the

U.S. Atomic Energy Commission

Reconnaissance Study 

of Uranium Deposits 

in Arizona

By H. C. GRANGER and R. B. RAUP

CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

GEOLOGICAL SURVEY BULLETIN 1147-A

Prepared on behalf of the

U.S. Atomic Energy Commission

UNITED STATES ^GOVERNMENT PRINTING OFFICE, WASHINGTON : 1962
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

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

Washington 25, D.G.
CONTEXTS

	Page 

Abstract _ -____________________-__-_--..---__-_--__-___-_-________ A-1

Introduction. ______________________________________________________ 1

Description of deposits___-_-____--__-__-..--__-__---__-_-_---__--__- 3-

Cochise County.______________________________________________ 3-

Fluorine Hill deposit________-__-..______________------_-____ 3-

Robles Spring deposit-______________________________________ 4

Coconino County_____________________________________________ 7

Hosteen Nez Mining Company deposits..-._________________ 7

Orphan claim....__________________________________________ 7

Gila County..._______________________________________ 12

Deposits in the Dripping Spring quartzite-....-..----_________ 12

Graham County_______________________________________________ 15

Golondrina claims--_-___-__-__-___-__--_--__--_--_---_---_- 15

Maricopa County._____________________________________________ 15

Black Mountain claims______________-_-________--___-__-- 15

Lucky Strike claim....___________ __________________________ 16

Mohave County__--_------_--_---_-___________________________ 16

Catherine and Michael claims. __________ ____________________ 16

Hack's mine.--__-___________ ______________________________ 18

Jim Kane mine__________________________________________ 21

Red Hills prospect___________ ______________________________ 22

Summit mine----_-__-_______.._______-___-__-__-_-__-__-___ 22

Navajo County________________________________________________ 23

Anna Bernice claims__-_--__-.._--____-_-____--_---_--__-___ 23

Petrified Forest area_______-_..___________-_____-_-_-__--__- 24

Petrified Forest National Monument___________________ 24

Tract No. !_______________________________ 24

Tract No. 2__________._._________________ 25

Pima County.___-____-_____-_-_-_-_.-___-___-_---___-__-__-___ 25

Black Dike deposit____-___________-___-___________-_______ 25

Copper Squaw mine__ ______________________________________ 29

Glen claims_________________-___.__________________-_______ 30

Iris and Natalia claims. _ ____________________________________ 30<

Lena No. 1 and Genie No. 1 claims----_----_----_------_-__- 31

Sure Fire No. 1 claim-_______-___________-_---__--_____-__- 34

Van Hill No. 5 claim___________________________ 36

Van Hill Nos. 7 and 8 claims______________________________ 36

Pinal County _____________________________________________ 38-

Honey Bee No. 4 claim.__________________________________ 38

Shorty claims________-________--..___---_-_-_-_____-_______ 38

Wooley No. 1 claim______________________._________________ 38'

in
IV CONTENTS

Description of deposits Continued Page

Santa Cruz County________________-_____________-_-___-_______ A-39

Annie Laurie claims_____________________________________ 39

White Oak property...__________________________________ 42

Yavapai County________________________________________ 44

Abe Lincoln mine_____________________________________ 44

Cuba and Independence claims____________________-_-_______ 46

Kitten No. 1 claim___________-________-----_-___--______ 46

Peeples Valley mine______________________________________ 47

Yuma County____________________________________________ 48

Atom claims_____________-__----____--------_---------____ 48

McMillan prospect_____---_-------_---------------------_- 48

Conclusions.. ______-________-____-__------------------__-----_---_ 49

References cited___________________---__-___-____-_-----------_____ 50

Index_____________________________ _ ____ 53

ILLUSTRATIONS

Page 

FIGUBB 1. Index map of Arizona_______-__--__--_----------________ A-4

2. Geologic sketch map of the Robles Spring deposit __ 6

3. Diagrammatic cross section of the collapse structure on the

Orphan claim________________________-__ ________ _ 8

4. Geologic sketch map, Catherine and Michael claims_________ 17

5. Composite sketch of workings, Hack's mine________________ 19

6. Geologic sketch map of the Black Dike deposit ____ _ 27

7. Section and plans of the Black Dike shaft__ __ __ 28

8. Sketch map of the Lena No. 1 claim___ __ 32

9. Section and map of the discovery shaft, Lena No. 1 claim__ 33

10. Diagram outlining radioactive rocks on the Van Hill Nos. 7

and 8 claims.._________ .. 37

11. Geologic map of the Annie Laurie prospect, Ruby district _ _ _ 40

12. Geologic sections, Annie Laurie prospect, Ruby district 41 

13. Map of part of the White Oak No. 1 adit.___ ____ 43
CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

RECONNAISSANCE STUDY OF URANIUM DEPOSITS

IN ARIZONA

By H. C. GRANGER and R. B. RAUP

ABSTRACT

Between 1950 and 1954 a large number of deposits in Arizona were examined 

in search of uranium-bearing minerals in minable concentrations. This report 

describes most of the localities at which anomalous radioactivity was detected.

Five of the localities are of particular interest, either because uranium is produced from them or because of their unusual geologic setting. The deposit on 

the Orphan claim, in Coconino County, contains material equivalent in radioactivity to as much as 12.5 percent U in a pipelike body, and the deposit exposed in Hack's mine in Mohave County is in a somewhat similar pipe. The 

deposits in the Dripping Spring quartzite of Precambrian age in Gila County 

are unusual in that they appear to be genetically related to diabase. A considerable quantity of uraninite-bearing ore has been produced from several of 

the many deposits in siltstone, and siltstone metamorphosed to hornfels, within 

the Dripping Spring. The economic possibilities of the Annie Laurie prospect in 

Santa Cruz County could be evaluated by exploratory drilling to the east of the 

eastward-dipping fault zone. Earlier drilling west of the faults gave negative 

results. Specimens of uranium ore found on the dumps of the Abe Lincoln mine 

in Yavapai County may indicate the presence of small but rich pockets of ore in 

the mine, but the workings are inaccessible because of caving and flooding.

The deposits in the Dripping Spring quartzite have received additional study 

by us, and the deposit on the Orphan claim recently has been extensively developed. Additional study of Hack's mine might be profitable, and the Annie 

Laurie and Abe Lincoln deposits might be worthy of further study and 

development.

INTRODUCTION

As interest in the uranium deposits of Arizona increased after 

World War II, owing to the immediate need for fissionable materials, 

the U.S. Geological Survey examined known and reported occurrences 

of uranium in Arizona and searched for new deposits on the basis of 

geologic evidence. The more notable uranium deposits examined by 

the authors between 1950 and 1954 are described in this paper.

A-l
A-2 CONTRIBUTIONS TO THE GEOLOGY OP URANIUM

Granger, accompanied at times by E. P. Kaiser and J. W. Adams, 

examined reported occurrences of uranium in Arizona during parts 

of 1950 and 1951. Raup, with D. V. Haines, looked for previously 

unknown occurrences of uranium in Arizona from late in 1952 until 

March 1954. The area in which he worked did not include Coconino, 

Apache, and Navajo Counties, nor the northern half of Mohave 

County. Granger and Eaup made an extensive study of deposits in 

the Dripping Spring quartzite in 1954-57, and Granger examined the 

Orphan deposit in 1958 for the U.S. National Park Service. Summaries of these later investigations are included in this report. More 

recent studies of several of the deposits discussed have been made by 

mother geologists, but, except for brief statements about samples, none 

of the results of this later work are cited in this report. Publications 

 of some of these workers are, however, referred to in the text. Our 

work was done on behalf of the Division of Eaw Materials of the 

U.S. Atomic Energy Commission.

Uranium minerals in Arizona occur in a wide variety of geologic 

settings. Deposits in sandstone are common in the northern part of 

the State, but not all these are of the "Plateau type," or layered, 

nearly concordant deposits that generally occur in continental sandstones. Aberrant occurrences are found at Hack's mine and on the 

Orphan claim. Veinlike deposits occur abundantly in altered siltstone in Gila County, near the center of the State, and others occur 

in various kinds of rock throughout the southern half of the State. 

Deposits of disseminated uranium minerals occur in Mohave, Pima, 

Graham, and Gila Counties. The mineralogy of the deposits is also 

diverse; for example, the principal uranium-bear ing mineral is carnotite, metatorbernite, kasolite, pyromorphite, or uraninite at one or 

more of the deposits described in this report. Some rarer minerals 

that have been identified include bassetite, schoepite, dumontite and 

saleeite.

Figure 1 shows the locations of all deposits described in this report. 

In the text, descriptions of the geology and mineralogy of the individual deposits are arranged alphabetically according to the counties 

in which they occur. Uranium-assay data given in the text are from 

several laboratories, not all of which use the same system of reporting 

results. Therefore, some analyses are in terms of percent U or eU 

(uranium or equivalent uranium) whereas others are in terms of 

percent U3O8 or eU3O8 (uranium oxide or equivalent uranium oxide).

E. D. Wilson and J. W. Anthony of the Arizona Bureau of Mines, 

and Steven Malloy, LaMar Evans, and others at the Southwest Experimental Station of the U.S. Bureau of Mines extended many 

courtesies and gave us many helpful suggestions. R. J. Wright of
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-3

the U.S. Atomic Energy Commission conducted Granger to several 

deposits and supplied unpublished information. Many miners and 

prospectors were especially helpful.

DESCRIPTION OF DEPOSITS

The following descriptions of deposits are based on work that 

ranged from reconnaissance examinations to detailed field examinations accompanied by laboratory study. The information on the 

deposits therefore ranges widely in completeness. The amount of 

data given in the description of any deposit is not necessarily an indication of its relative economic importance. Deposits previously described in published reports have been described only briefly in the 

present report, and the reader should consult the articles listed under 

"Eeferences cited" for more details concerning these deposits.

COCHISE COUNTY 

FLUORINE HILL DEPOSIT

The Fluorine Hill deposit is in sees. 33 and 34, T. 17 S., E. 25 E., 

2,1/2 miles east of Pearce. Fluorine Hill is mainly composed of partly 

silicified rhyolite cut by narrow and discontinuous fractures. Most 

of the fractures are stained with hydrous iron oxides and are partly 

filled with veins of calcite and hematite, rarely more than 2 or 3 

inches wide.

The greatest amount of radioactivity was detected in a prospect pit 

on the south side of the hill, near its crest. A narrow carbonate vein 

exposed in this pit contains a small amount of dark-purple fluorite 

and flecks of a yellow uranium-bearing mineral that is probably 

uranophane or autunite. The vein can be traced for less than 25 feet 

on the surface, even with the aid of a scintillation meter. A grab 

sample of the vein material exposed in the prospect pit contained 0.11 

percent uranium.

The other prospect pits and mine dumps 011 Fluorine Hill contained 

no material that was significantly more radioactive than the host rock, 

and no concentrations of uranium-bearing minerals were found in any 

of the fractures exposed at the surface. The rhyolite porphyry host 

rock, however, showed a slightly abnormal radioactivity in all the 

exposures checked on Fluorine Hill and the other hills nearby. A 

representative sample of the rhyolite porphyry contained 0.008 percent ell.

The secondary uranium minerals found in the prospect pit on 

Fluorine Hill may have been derived from the host rock and concentrated in the vein by circulating ground water, or they may have 

replaced primary uranium-bearing minerals that were deposited in
A-4 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

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FIGUEH 1. Index map of Arizona, showing location of uranium deposits described in this 

report. (See table on facing page for names of deposits.)

the vein from hydrothermal solutions. The latter explanation seems 

the more probable, for fluorite and uranium-bearing minerals are 

commonly associated in hydrothermal deposits.

KOBLES SPRING DEPOSIT

The Robles Spring deposit is in the SW^ sec. 30, T. 13 S., R. 19 E., 

about 30 miles east of Tucson. It is explored by a short adit and a 

shallow prospect pit. The adit follows a nearly vertical iron-stained 

shear zone that rolls and merges with the bedding below the adit level. 

The workings, which were probably dug in search of precious metals,
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-5

Gochiae County

1. Fluorine Hill deposit

2. Robles Spring deposit

Coconino County

3. Hosteen Nez Mining Co. deposits

4. Orphan claim

Gila County

5. Dripping Spring quartzite

Graham County

6. Golondrina claims

Maricopa County

7. Black Mountain claims

8. Lucky Strike claim

Mohave County

9. Catherine and Michael claims

10. Hack's mine

11. Jim Kane mine

12. Red Hills prospect

13. Summit mine

Navajo County

14. Anna Bernice claims

15. Petrified Forest area

16. Tract No. 1

17. Tract No. 2

Pima County

18. Black Dike deposit

19. Copper Squaw mine

20. Glen claims

21. Iris and Natalia claims

22. Lena No. 1 and Genie No. 1 claims

23. Sure Fire No. 1 claim

24. 25. Van Hill

Nos. 5, 7, and 8 claims

Final County

26. Honey Bee No. 4 claim

27. Shorty claims

28. Wooley No. 1 claim

Santa Cruz County

29. Annie Laurie claims

30. White Oak property

Yavapai County

31. Abe Lincoln mine

32. Cuba and Independence claims

33. Kitten No. 1 claim

34. Peeples Valley mine

Yuma County

35. Atom claims

36. McMillan prospect

are not related to the structure that controlled the deposition of radioactive minerals.

The uranium-bearing material occurs north of the adit, along a 

nearly vertical northwest-trending fault which has placed limestone 

in contact with schist (fig. 2). The area has received little geologic 

study and the ages of the rocks are unknown; the limestone, however, 

is probably Paleozoic and the schist Precambrian. The former includes beds of fine crystalline limestone, shaly limestone, pebble 

conglomerate, and limestone-quartzite pebble conglomerate. The 

schist is fine grained, gray, and locally calcareous, and it contains 

numerous blebs of pegmatitic quartz. Its foliation trends slightly west 

of north and dips about 50° E.

The length and displacement of the fault were not determined but 

may be relatively large. The fault zone, which is characterized by 

local fractures, breccia, iron stain, and less resistance to erosion, is 

weakly radioactive along an outcrop length of 100 feet. The greatest 

radioactivity is in two fault blocks, or horses, of carbonaceous fractured and iron stained shale in the fault zone; the larger block is 

about 15 feet long and 5 feet wide, the other about 10 feet long and 

nearly 4 feet wide. Many of the fractures are filled with a powdery

631432 62 2
A-6 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

CONTOUR INTERVAL 10 FEET 

DATUM IS ASSUMED EXPLANATION

2 £_ Contact, approximately located

Fault

Dashed where approximately 

located

60

Shear zone, showing dip

Strike and dip of beds

55/ 

Strike and dip of foliation

\ 

Adit

X 

Prospect

Schist 

Geology and topography by H. C. Granger, 1951

FIGURE 2. Geologic sketch map of the Robles Spring deposit, Cochise County, Ariz.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-7

yellow mineral, probably an iron sulf ate. Iron stain and carbonaceous 

matter are less abundant in the smaller horse.

A channel sample across the larger horse contained 0.004 percent 

U and 0.078 percent ell. This suggests that some of the original 

uranium may have been removed by leaching.

The radioactivity may be from minerals deposited by solutions percolating in the fault zone or may be from material mechanically emplaced by the fault. The carbonaceous shaje appears to have been 

favorable for precipitation of uranium, but its source is not known. 

Finding the source of the shale would be of great help in prospecting 

for more deposits of the Robles Spring type. If that were done, it 

could be determined whether all the shale is radioactive, or only the 

shale in the two horses in the fault zone.

coco]srmo COUNTY

HOSTEEN NEZ MINING CO. DEPOSITS

The Hosteen ISTez Mining Co. owns several deposits in T. 27 N., E. 

12 E., on the Navajo Indian Reservation, about 40 miles north-northwest of Winslow.

Two deposits examined are in varicolored shale and sandstone tentatively assigned to the upper part of the Chinle formation of Late 

Triassic age. The northern deposit is exposed in the walls of a draw; 

the radioactive material is in the south edge of a lens composed of 

sandy shale, sandstone, and a few clay pebbles. A yellow uranium 

mineral partly replaces clay pebbles, coats fractures and bedding surfaces, and impregnates manganese-rich concretions and carbonized 

fossil wood. The manganese concretions are commonly very rich in 

uranium; one specimen contained 3.88 percent U3O8 . An 8-foot sample 

across the radioactive lens, however, contained only 0.035 percent 

uranium.

Between the northern and the southern deposits the float contains 

uraniferous manganese nodules, which evidently weathered out of the 

very small, widely separated concretionary deposits.

The southern deposit caps the summit of a small knoll. Its uranium 

occurs chiefly in manganese-rich concretions and partly silicified 

fossil wood, but locally the sandstone itself is radioactive. About 

4 tons of hand-picked ore from the surface of the knoll contained 0.20 

percent U3O8. A selected sample collected by Granger contained 0.44 

percent U.

ORPHAN CLAIM

The Orphan claim is a patented mining claim entirely within the 

Grand Canyon National Park, immediately west of Maricopa Point on 

the south rim of the Grand Canyon and approximately 6,500 feet
CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

northwest of the park headquarters at Grand Canyon, Ariz. The 

claim was located in 1893 and was patented before the establishment of 

the park. It was originally worked for the copper content of its ores, 

but mining activity since 1951 has been centered on uranium. Western Gold & Uranium, Inc., has been largely responsible for exploring, 

developing, and mining the uranium deposit.

The rocks on the Orphan claim are Pennsylvanian and Permian in 

age, although older rocks are exposed in the canyon wall below the 

claim. The rocks, from older to younger, are the Supai formation of 

Pennsylvanian and Permian age, and the Hermit shale, Coconino sandstone, Toroweap formation, and the Kaibab limestone, all of Permian 

age. The Kaibab limestone forms the rim of the canyon (fig. 3).

Profile from topographic map of the Grand 

Canyon National Park (east half)

Stratigraphic section by Kofford 

(written communication, 1958)

Supai formation

Redwall limestone

Temple Butte limestone

550ft

FIGURE 3. Diagrammatic cross section of the south wall of the Grand Canyon through 

the collapse structure on the Orphan claim, Coconino County, Ariz.

The uranium deposit is in a nearly vertical, circular to elliptical 

pipelike body of collapse breccia. Exposed parts of the collapse structure at the surface cut both the Coconino sandstone and the Hermit 

shale; most of the rock exposed by mining within the structure is 

Coconino sandstone. The ultimate depth to which the structure extends is not known, but it may cut all the formations exposed in the 

walls of the Grand Canyon (fig. 3).
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-9

At the time of the original examination by Granger, in 1951, there 

were three small workings on the property, all dating from the early 

copper mining. The upper working was a small pit about 5 feet deep 

at the contact between the Coconino sandstone and the Hermit shale, 

about 35 feet southeast of the collapse structure. A small pool of 

water in it suggested that the pit may have been dug primarily as a 

source of water. A little efflorescent material on the walls was weakly 

radioactive.

The middle working, which was about 80 feet lower than the upper 

working, was in Coconino sandstone along the southeast margin of 

the collapse structure. The main adit trended S. 20° W. for about 

25 feet, and a 15-foot working branched from the main adit near the 

portal. A fracture in the main adit contained malachite and iron 

oxides, but other nearby fractures were essentially barren. The sandstone contained blebs and streaks of copper sulfate minerals, chrysocolla, hematite, and some sulfide minerals. The walls of the adit 

were covered with efflorescent iron and copper minerals associated with 

gypsum. A composite sample composed of rock chips taken every 

5 feet along the walls of the main adit contained 0.043 percent U and 

0.064 percent eU.

The lower working was in the lowest outcropping part of the collapse structure, about 150 feet lower than the normal base of the Coconino sandstone. An adit extended S. 55°-50° W. for 45 feet, then 

turned sharply and extended S. 28° E. for 25 feet. Within the adit 

nearly all the sandstone was impregnated with pyrite, arsenopyrite, 

chalcopyrite, and hematite; secondary and efflorescent minerals were 

chrysocolla, chalcanthite or brochantite, and gypsum. At the portal 

of the adit was a vertical iron-stained shear zone about 5 feet wide that 

locally contained torbernite. The strike of this shear zone was about 

N. 25° W., nearly normal to the trend of the adit.

A composite sample composed of rock chips taken every 10 feet 

along the walls of the lower adit contained only 0.006 percent U. In 

sharp contrast, 3 channel samples cut across the torbernite-bearing 

shear zone near the portal contained 0.093 to O.T2 percent U, and 0.21 

to 1.00 percent eU. A selected sample of iron-stained rock on a 

weathered wall of the shear zone contained only 0.039 percent U but 

12.5 percent eU.

Since the original examination, Western Gold & Uranium, Inc., acquired the property and sank an underground shaft collared in a short 

adit near the portal of the lower working. From this shaft they have 

driven more than 1,500 feet of workings on several levels. In 1959, 

a 1600-foot shaft was sunk from the canyon rim and a crosscut more 

than 800 feet long was extended into the collapse structure.
A-10 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

The geologic setting of the Orphan deposit was not well understood 

until Western Gold & Uranium, Inc., had done extensive mining and 

drilling. This exploration has demonstrated that the collapse structure has a fairly abrupt shoulder near the contact between the Hermit 

shale and the underlying Supai formation. It has a diameter of 

about 175 feet at the outcrop and widens downward to about 400 feet 

in the upper part of the Supai. Evidence from drill holes suggests 

that the north wall of the structure may be deflected northward once 

more in the lower part of the Supai formation, but no information is 

available on the attitude of the south wall for more than about 100 

feet below the shoulder.

The rocks in the collapse structure are highly fractured, bleached, 

and altered. Large blocks of sandstone, shale, and limestone are 

disoriented in relation to the stratification of the surrounding rocks. 

The blocks are displaced from their normal stratigraphic position but 

show remarkably little evidence of jumbling and mixing in some parts 

of the mine.

Blocks of Coconino sandstone are found at least 275 feet below 

their normal stratigraphic position. Hermit shale is rare in the upper 

mine workings and at the outcrop of the structure, but it is present 

in the lower workings as blocks of argillite and finely divided interstitial material between sandstone blocks. The limestone blocks are 

intermixed with the sandstone blocks and in some places replacement 

limestone forms a nearly homogeneous envelopelike mass as much as 

60 feet thick at the margins of the structure. Much of the limestone 

probably results from a calcitic replacement of blocks and fragments 

of Hermit shale.

The rock immediately outside the structure is almost invariably 

bleached and altered for a few feet, but nowhere is it known to contain 

ore, nor is it replaced by calcite.

The ore seems to be entirely within the collapse structure. Mining 

and drilling have shown that most of the ore within 175 feet below 

the outcrop is in an arcuate body that generally parallels and locally 

touches the north wall of the collapse structure. Other ore bodies, 

probably smaller and perhaps more poorly defined and discontinuous, 

occur against the south wall and elsewhere within the collapse structure. Much of the rock between the ore bodies also contains abnormal 

amounts of uranium and sulfide minerals but of a lower grade.

The ore bodies are seemingly localized for the most part in the 

zone in which the collapse structure increases in diameter in passing 

downward from the Hermit shale into the Supai formation. The 

results of drilling strongly suggest that the periphery of the collapse 

.structure is most favorable for ore and that this ringlike zone is thick-
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-ll

est just below the shoulder of the structure and narrows downward. 

There is almost no ore in drill cores from parts of the structure more 

than 400 feet below the outcrop. The central part of the structure, 

enclosed by the favorable peripheral zone, is almost entirely devoid 

of ore. Within the favorable peripheral zone the rocks appear to be 

more shattered and the fragments of different rocks more mixed than 

elsewhere. The most favorable host for uranium ore seems to be shattered sandstone, although much of the limestone contains ore of good 

grade. Shattered Hermit shale or argillite, where not at least partly 

replaced by limestone, is generally a poor host rock.

The dominant ore mineral in the deposit is uraninite. It is generally 

disseminated in the host rock but locally forms lenses or veins several 

inches thick of relatively pure uraninite. It is associated with pyrite 

and other sulfide and sulfosalt minerals that contain copper, lead, 

zinc, cobalt, nickel, and molybdenum.

Secondary minerals of uranium, copper, and molybdenum are common on the surfaces of the mine workings but have little economic 

importance.

The geologic history of the collapse structure is uncertain. One 

concept is that it may have originated by a deep-seated explosion of 

gas of magmatic origin. Mr. Max Kofford, mine geologist at the 

Orphan claim (oral communication, 1958), considers that the explosion took place quite recently, probably in Quaternary time. No 

igneous rocks are known within the explored parts of the Orphan 

structure but possibly there may be some at depth.

The explosion shattered the rock and produced a megabreccia that 

settled into a position not far from the rock's original stratigraphic 

position. This megabreccia was indurated by pressure and cementation, forming a parallel-walled pipe nearly as competent as the surrounding sedimentary rocks, but sufficient open fractures remained to 

permit upward streaming of the fluids that possibly ascended from the 

source of the gas explosion. These fluids altered the rocks within 

and adjacent to the pipe and partly replaced them with calcium carbonate, which probably was derived from leaching of limestone strata below. Some of the altered and replaced rocks were again 

broken, probably as a result of continuing subsidence within the 

pipe after the solution and removal of the limestone below, and 

then further altered. Leaching of limestone adjacent to the pipe 

permitted collapse of the overlying Supai formation. This peripheral 

collapse zone worked upward until it reached the Hermit shale where 

it stopped, forming a shoulder or bottleneck. Solutions containing 

uranium, copper, and other constituents percolated through the 

altered and fractured rocks, depositing ore and gangue minerals
A-12 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

wherever the chemical, pressure, and temperature conditions were 

favorable. Ore bodies were formed along the more open channel ways, 

where conditions for precipitation were particularly favorable. 

Smaller amounts of ore minerals were also deposited in more restricted 

channelways and throughout the broken rock.

Another concept is that the collapse originated entirely by solution 

of underlying limestone, without any magmatic activity. The structure might then have developed somewhat in the way outlined above, 

except that the source of calcifying and mineralizing solutions would 

likely be ground water percolating through the Kaibab limestone and 

Coconino sandstone.

GILA COUNTY 

DEPOSITS IN THE DRIPPING SPRING QUARTETTE

The Dripping Spring quartzite of Precambrian age is extensively 

exposed in southeastern Arizona, but economic uranium deposits in 

that formation have been found only in Gila County, particularly the 

north-central part. Uranium deposits in the Dripping Spring were 

first noted early in 1950, but they received little attention until late 

in 1953. Between 1954 and 1958, we conducted a detailed study of 

these deposits, and they are therefore described more fully than most 

of the other deposits. Several geologists have described the uranium 

deposits in the Dripping Spring quartzite, including Wright (1950), 

Kaiser (1951), Mead and Wells (1953), R. G. Gastil \ Wells and Rambosek (1954), and Magleby and Mead (1955).

By 1956 about 100 uranium deposits had been found in the Dripping 

Spring quartzite. Less than 12 of these were being actively developed, 

but about 40 had been explored by drilling or drifting, in addition to 

the required assessment work.

The Dripping Spring quartzite is a formation in the relatively 

undisturbed and unmetamorphosed Apache group of younger Precambrian age, which consists of clastic, pyroclastic, and carbonate 

sedimentary rocks commonly capped by one or more flows of basalt. 

This group lies unconformably on older Precambrian gneiss, schist, 

and granitic rocks and is overlain disconformably by younger sedimentary rocks. The Apache group is extensively intruded by diabase, 

which occurs mainly in large sills but also forms dikes, gently crosscutting sheets, and irregular bodies.

The Dripping Spring consists of two members. The lower member 

is typically a reddish arkosic to orthoquartzitic sandstone. It is 

missing in the extreme northern part of Gila County, where the formation abruptly overlaps older rocks, but elsewhere in the county it

1 Gastil, R. G., 1953. The geology of the eastern half of the Diamond Butte quadrangle, 

Gila County, Arizona: California Univ. doctoral thesis.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-13

is 140 to 370 feet thick. The upper member, which contains all the 

known uranium deposits in the formation, is much finer grained and 

more thinly stratified than the lower member. It consists mainly of 

arenaceous siltstone but contains units that range in lithology from 

shale to coarse-grained orthoquartzite. Most of the uranium deposits 

are in gray siltstone strata near the middle of the upper member, but 

some deposits of secondary uranium minerals are lower in the member.

The siltstone favorable for uranium deposits is generally gray where 

unweathered; the color is due to 2 percent or less of extremely finegrained carbon and a little disseminated pyrite. It is abnormally rich 

in potassium, containing about 10 to 14 percent K2O, almost entirely 

in detrital and authigenic feldspar. Where cut by large diabase 

bodies, it is locally metamorphosed to hornfels and related rocks, 

which are even more favorable for uranium deposits than the unmetamorphosed siltstone.

The primary deposits are generally veinlike and nearly vertical. 

Their vertical extent is determined by favorable lithology and rarely 

exceeds 20 feet, but in some deposits it is 80 feet or more. Most of 

the veinlike deposits are less than 5 feet thick and about 100 to more 

than 300 feet long; their maximum length has not yet been determined. 

Favorable strata locally contain mantolike ore deposits extending 

laterally from the veinlike bodies.

Most of the veinlike deposits trend within a few degrees of either 

N. TO 0 W. or N. 20° E., parallel to joints. The outcrop of such a deposit is generally marked by a limonite-filled joint, but farther underground the joint is commonly unrecognizable or diverges from the 

trend of the deposit. However, most of the joints now visible are not 

the tight fractures along which the uranium minerals were deposited, 

but are postmineralization joints and were controlled in part by the 

deposits.

In some of the deposits in hornfels, the ore minerals are localized 

along breccia zones parallel to the principal joint system. These breccia zones are cemented by an aplitic rock.

The uranium minerals are generally disseminated in the host rock, 

but they also form short veinlets and irregular masses, particularly 

in the hornfels.

The primary uranium mineral in deposits adjacent to diabase is 

uraninite, largely in extremely small discrete grains. Some aggregates of these grains form masses that appear to be massive uraninite, 

but microscopic examination invariably discloses a multitude of 

rounded uraninite grains disseminated in a chlorite-rich matrix. Coffinite associated with uraninite was identified by X-ray methods in one 

specimen, but it is probably rare. No primary uranium minerals have

631432 62 3
A-14 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

been recognized in deposits not adjacent to diabase. Although extremely fine-grained uraninite may be disseminated in these deposits 

farther from diabase, it is probable that much of the uranium was 

adsorbed in the form of the uranyl ion on other minerals, such as clay, 

chlorite, and carbon.

Sulfide minerals, which probably formed later than the uranium 

minerals, are generally abundant in the deposits. The deposits in 

hornfels contain molybdenite, pyrrhotite, chalcopyrite, marcasite, 

galena, sphalerite, and pyrite, formed in approximately that order. 

Deposits in siltstone commonly contain all these minerals except molybdenite and pyrrhotite.

Weathered parts of deposits in hornfels contain abundant uranophane and sparse torbernite, associated with secondary copper and iron 

minerals, a little uranif erous hyalite, and gypsum. In the weathered 

parts of deposits in essentially unmetamorphosed siltstone, metatorbernite is the most abundant uranium mineral; but bassetite, saleeite, uranophane, meta-autunite, and uraniferous hyalite have also 

been identified, together with the same secondary nonuraniferous minerals that occur in the hornfels.

A genetic relationship between the uranium and diabase is suggested 

by the proximity of most of the deposits to diabase and by the association of uranium minerals with sulfide minerals, such as pyrrhotite 

and molybdenite, that are generally believed to have been formed at 

high temperatures.

Analyses of various facies of the diabase suggest that the diabase 

magma lost uranium as it cooled. The chilled borders of the diabase 

bodies contain more uranium than the inner parts, and they show no 

evidence of having been enriched in uranium from the enclosing 

sedimentary rocks. It therefore seems probable that the diabase 

magma, when injected, contained at least as much uranium as the 

borders do now but that the inner parts of the diabase intrusive bodies 

expelled uranium-bearing solutions during their slow crystallization. 

These solutions presumably moved outward through the surrounding 

rocks along permeable strata and tight joints until they came in contact with rocks rich in original carbon and pyrite or in carbon, pyrite, 

and clay where, under strongly reducing and adsorptive conditions, 

the uranium was deposited. Subsequent studies by Neuerburg and

-Granger (1960) substantiate the conclusion that the diabase lost uranium and that the uranium was incorporated in the deposits, but they 

indicate that the uranium was expelled from the diabase by late-stage

 deuteric solutions which also altered and probably added uranium to 

the chilled borders.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-15

GRAHAM COUNTY 

GOLONDRINA CLAIMS

The Golondrina property, in the S% sec. 12, T. 11 S., E. 25 E., 

is a block of 21 claims held in 1951 by M. V. Lee of Dragoon. Fractures on the property are filled with radioactive pyromorphite associated with a little quartz and limonite. Deposits of pyromophite, 

lead chlorophosphate, apparently were localized, at least in part, by 

a 1- to 2-foot layer of agglomerate or flow breccia that separates 2 

successive flows of porphyritic volcanic rocks. The pyromorphite 

occurs in cavities and fractures in the breccia, and also in fractures 

in the porphyritic rocks nearby. A short adit follows the breccia 

for about 20 feet, and 2 open pits expose what appears to be the basal 

part of the upper flow. In the larger pit the pyromorphite is associated with traces of chalcopyrite, chalcocite, and malachite.

The radioactivity is not everywhere in direct proportion to the 

quantity of pyromorphite, whose uranium content thus appears to 

be variable. Tests by the U.S. Atomic Energy Commission indicate 

that the pyromorphite contains as much as 0.6 percent U (K. J. 

Wright, written communication, 1950), probably as a constituent of 

the mineral. A sample tested by the U.S. Bureau of Mines contained 

0.26 percent eU3O8 and 0.221 percent U3O8 (J. N. Faick, 1953, U.S. 

Defense Minerals Exploration Administration docket 2977). The 

radioactive material, though widespread, is mostly of very low grade.

MLAEICOPA COUNTY 

BLACK MOUNTAIN CLAIMS

The Black Mountain claims and the Black Mountain Vanadium 

claims are on the west end of the Vulture Mountains, about 12 miles 

southeast of Aguila. In 1951 the claims were owned by Milton Hay 

of Aguila and contained several shallow prospect pits and trenches.

The uranium deposits occur in shaly beds of buff to white limy 

bentonitic tuff, from 100 to 200 feet thick. The tuff is exposed along 

a northwest-trending cuesta that is capped by a mafic lava flow. 

Underlying the tuff are gneiss and schist cut by pegmatite dikes. The 

tuff beds strike northwest and dip 60°-65° SW.; the steeper dips are 

caused by slumping. Bedding planes and fracture surfaces are thinly 

coated with gypsum and a yellow uranium mineral, probably carnotite 

(Hewett, 1925).

Although the tuff probably contains traces of carnotite for a distance of a mile or more, none of it is known to contain much more 

than a trace. A selected sample recorded by Hewett (1925) contained 

only 0.009 percent U3O8 .
A-16 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM 

LUCKY STRIKE CLAIM

The Lucky Strike claim, about 13 miles by road north of Morristown, was owned in 1951 by John Kichie and James Russell of Morristown. A 60-foot adit on the claim develops a narrow vein in 

Yavapai schist of Precambrian age.

On the dump was several tons of radioactive material containing 

galena, chalcopyrite, wulfenite, chrysocolla, chalcocite, willemite(?) 

and pyromorphite( ?) in a quartz gangue, but no recognizable uranium minerals were found. A grab sample of this material contained 

0.025 percent U. Although the size of the fragments indicates that 

they were mined from a fissure vein at least 8 inches thick, no remnant 

of any vein of this size and composition was found in the adit, and 

because the vein material on the dump has been broken clean of its 

wall-rock, its source is hard to determine. Perhaps the ore formed a 

pod or pocket in the schist or in an otherwise inconspicuous vein. 

Perhaps it was all mined out, or possibly it came from some other 

mine.

MOHAVE COUNTY 

CATHERINE AND MICHAEL, CLAIMS

The Catherine and Michael claims are near the west-facing escarpment of the Aquarius Cliffs, about 8 miles east of the road between 

Kingman and Wikieup and 50 miles southeast of Kingman. They 

were owned in 1951 by E. H. Carr and others of Los Angeles, Calif.

The Aquarius Cliffs, which are rugged slopes rather than cliffs, 

overlook a fault-trough valley underlain by a downthrown block. 

They consist mainly of Precambrian granite, gneiss, and schist, intruded by numerous dikes of aplite and pegmatite. The crest and. 

parts of the escarpment are covered with lava and pyroclastic rocks; 

the lower slopes consist mainly of valley fill and terrace gravels.

The claims extend along a small valley sharply incised into the 

escarpment. On the east wall of the valley are exposed tilted strata 

of sandstone, shale, and limestone that overlie Precambrian granite on 

the west and are faulted against it on the east (fig. 4). On the west 

wall of the valley are exposed flat-lying arkosic grit and conglomerate 

strata, which are unconformable on steeply dipping strata beneath. 

Several hundred feet north of the claims a sheet of fine-grained mafic 

igneous rock containing limestone inclusions is exposed above the tilted 

sedimentary rocks; whether this is extrusive or intrusive was not 

determined.

Detailed study of the rocks in the Aquarius Cliffs was not made by 

the geologists who have visited this region in the past. Lee (1908) 

and Schrader (1909) briefly discuss the areal geology of the region,
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-17

but they do not mention the tilted sedimentary rocks; nor does Wilson 

(1941), though he briefly describes the pegmatites and veins that 

contain tungsten minerals. Morrison (1940) mentions tilted "lake 

beds" that include concretionary limestone, volcanic ash, gypsum, 

analcite-bearing sandstone, diatomite, and bentonite, locally interbedded with basaltic lavas, but he does not give their age. These are

EXPLANATION

500 

I

Radioactive opal

0,007

Percent uranium in

channel sample

APPROXIMATE VERTICAL AND HORIZONTAL SCALE Geology by H. C. Granger, 1951 

FIGURE 4. Geologic sketch map, Catherine and Michael claims, Mohave County, Ariz.

evidently the rocks in which the uranium deposits occur on the Catherine and Michael claims, yet Morrison's map shows only the granitic 

basement rocks in the vicinity of the claims.

The uranium deposits occur on the east side of the small valley in 

a thinly laminated and poorly consolidated limestone unit, 20 to 30 

feet thick, which strikes N. 20°-30° W. and dips 25°-30° NE. The
A-1S CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

limestone conformably overlies a series of sandstones and shales and 

is disconformably overlain by arkosic grit and conglomerate. The 

limestone is locally replaced by milky white and greenish opal; both 

are commonly stained with irregular patches of black manganese 

oxide and are fluorescent. The greenish opal is more brightly fluorescent and much more radioactive than the milky white opal, which is 

virtually nonradioactive. The greenish opal, through less common 

than the white, is scattered throughout a layer as much as 10 feet thick 

along the strike for nearly 800 feet in sufficient quantity to make almost the entire layer radioactive. Perhaps the uranium is held as 

ions within the molecular lattice of the opal, for no uranium minerals 

were identified in the radioactive material.

A small selected specimen of fluorescent green opal contained 0.2 

percent U. This is much higher than the average uranium content 

of the deposit, but it shows how much uranium can be contained in 

opal that apparently contains no uranium minerals. Three channel 

samples believed to be representative of the uranif erous rock contained 

0.005 to 0.013 percent U very near equilibrium.

HACK'S MINE

Hack's mine, also known as the Hack Canyon uranium mine, is on 

a group of five claims named Hack's and Hack's Nos. 2, 3, 4, and 5 

claims. These claims are in Hack Canyon, in sec. 26(?), T. 37 N., K. 

5 E., about 37 miles by road southwest of Fredonia. They were acquired in 1940 by Clair Pearson, A. E. Jenson, and three associates, 

all of Fredonia. Only the deposits on Hack's and Hack's No. 2 claims 

were examined.

The deposit at Hack's mine is explored by a 30-foot shaft, a 45- 

foot adit, 2 inclined shafts, and over 200 feet of drifts and crosscuts 

(fig. 5). Small amounts of copper ore have been produced from the 

mine at various times since 1920, and uranium minerals were discovered 

while the mine was being worked for copper late in World War II 

(Dunning, 1948).

Upper Hack Canyon is cut into a section of Permian sedimentary 

rocks from the Hermit shale to the Kaibab limestone. The copperuranium deposit on Hack's claim crops out on a steep slope just below 

the contact between the cliff-forming Coconino sandstone and the 

underlying Hermit shale. At the surface, many fractures in broken, 

slumped Coconino sandstone are stained with green copper minerals 

and minor metatorbernite. The shaft is collared in Coconino sandstone talus. Beneath this are at least 15-20 feet of slumped Coconino 

sandstone in the throat of a pipelike collapse structure that seems to 

be similar to the structure on the Orphan claim. Underlying the
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-19

EXPLANATION

Medium-grained sandstone 

and breccia

Contact, approximately located

Strike and dip of beds

Adit level

First level

-28 feef

Second level 

-37 feet

CO

Shaft going above and 

below level

Head and foot of winze 

Chevrons point down

10 i

20 

I

Geology by H. C. Granger, 1951 

30 FEET

FIGURE 5. Composite sketch of workings, Hack's mine, Mohave County, Ariz.
A-20 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

slumped sandstone is fractured bleached Hermit shale. Slumped 

coarse rock debris and talus at the outcrop of the deposit as well as in 

the upper workings had caused earlier investigators to believe that 

the deposit at Hack's mine is localized primarily in a surficial slump 

block of Coconino sandstone.

The rock within the mine is largely fine-grained indistinctly bedded 

dirty-gray altered sandstone of the Hermit shale. Near the southwest face of the first level this rock grades without any structural 

break into normal red unaltered Hermit shale.

Within the mine there are several elongate, ill-defined zones of 

breccia consisting of fragments of both fine- and medium-grained 

.sandstone in a matrix of predominantly fine-grained sandstone. 

These zones generally dip steeply but locally follow bedding planes.

-In a thin section of the breccia it was found that many of the quartz 

grains were secondarily enlarged by overgrowths. Much of the 

medium-grained sandstone may therefore be silicified Hermit shale. 

As the breccia contains no cavities, it was probably cemented under 

considerable pressure.

The primary uranium minerals have been deposited in these brecciated zones and in some of the coarser grained sandstones. The breccia, 

which commonly is light red, owing to secondary iron oxides, contains 

black spots that are markedly radioactive. These spots probably

 consist of chalcocite mixed with a little pitchblende (J. W. Gruner, 

written communication, 1950.) No other metallic minerals were identified, but they were undoubtedly present before the rock was weathered, for the sides of fractures in the breccia are partly coated with 

chalcanthite, brochantite, erythrite or bieberite, and yellow uranium 

minerals, including zippeite( ?). Farther out the altered fine-grained 

sandstone contains malachite and metatorbernite along fractures and 

bedding planes and as interstitial fillings.

Nine samples taken during this examination contained 0.004 to 0.28 

percent U. The samples with a higher uranium content were mainly 

from the breccia zones. To mine the deposit efficiently, it would be 

necessary to know the extent and distribution of breccia zones.

About 500 tons of the rock on a dump near the portal of the tunnel 

in 1951 was radioactive. The radioactivity, as measured about 2 feet 

from the surface by means of a portable field meter with a 6-inch 

probe, averaged about 0.10 mr per hr (milliroentgens per hour), 

which is estimated to be equivalent to nearly 0.1 percent U. Ore 

containing 0.1 to 0.2 percent U could be recovered by hand-cobbing.

The Hack's mine deposit seems to be in a collapse structure very 

similar to that in which the Orphan deposit (p. A-Y to A-12) is localized. Hack's mine is probably on the southeast side of such a structure,
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-21

as is indicated by the curvature of the breccia zones shown in figure 5. 

These breccia zones are quite likely the faults along which the collapse movements occurred. The talus above the mine workings 

probably resulted from slumping of fractured Coconino sandstone 

within the collapse structure after this rock was exposed by canyon 

cutting.

A small amount of a pale-yellow powdery uranium mineral was 

recovered from a prospect pit on Hack's No. 2 claim, about 500 to 600 

yards northeast of Hack's mine. The mineral was not identified, but 

spectrographic analyses show that it contains significant amounts of 

uranium, silica, and phosphate. It occurs along joints and bedding 

planes in a shaly rock near the contact between the Coconino sandstone and the Hermit shale, probably in the Hermit shale. This pit 

has not uncovered an economically significant uranium deposit, but it 

demonstrates the possible widespread occurrence of uranium in the 

vicinity of Hack's mine.

JIM KANE MINE

The Jim Kane mine is in sec. 8, T. 22 N., R. 17 W., in the Wallapai 

district, about 10 miles north of Kingman (E. P. Kaiser, written 

communication, 1951). It was owned in 1951 by Jim Kane, who lived 

at the mine and had opened it in search of lead and zinc minerals.

The mine is in Precambrian gneiss. It has three adit levels, which 

follow a wide shear zone that strikes N. 60° W. and dips steeply 

northeast. Individual veins and shears within this zone contain 

scattered galena and sphalerite in a siderite gangue. One vein, about 

3 feet wide, contains small amounts of radioactive material. Weak 

radioactivity is traceable for about 120 feet along the vein on the 

middle level, and stronger radioactivity for about 60 feet horizontally 

along the vein in a stope 23 feet above the level. The abnormal radioactivity coincides with a part of the vein that is reported to contain 

over 5 percent lead, whereas other parts contain 1 percent or less. No 

uranium minerals were recognized, although the U.S. Bureau of 

Mines has reported that the vein contains pitchblende (R. J. Wright, 

oral communication, 1950). Chalcedony and gypsum that locally 

coat the mine walls fluoresce yellow green and bright red, respectively.

Two samples taken by Kaiser, which probably represent the grade 

of the vein at the richest part of the ore shoot, contained 0.067 and 

0.042 percent U. A. J. Rambosek (written communication, 1952), 

took two samples from unspecified localities in the mine that contained 

0.003 and 0.006 percent U3O8 .

631432 62 4
A -22 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM 

RED HILL/S PROSPECT

The Red Hills uranium prospect is in sec. 7, T. 11 N., R. 13 W., 

about 6 miles northwest of the old settlement at Alamo. In 1951 the 

claims were owned by E. W. Tate of Wenden.

The rocks at the Red Hills prospect belong chiefly to the Artillery 

formation, probably of Eocene age, which is underlain by Precambrian schist and gneiss (E. P. Kaiser, written communication, 1951). 

Nearby exposures indicate that the Artillery formation has been 

thrust over the Precambrian rocks at a low angle. The Artillery 

formation in the prospect area is represented by a breccia consisting 

of fragments of schist, felsitic material, conglomerate, and limestone 

cemented with silica, carbonates, and manganese oxide. This is probably a fault breccia related to the low-angle thrust fault, but it may 

be in part a sedimentary breccia at the base of the Artillery formation 

(Lasky and Webber, 1949).

A prospect pit was sunk on a radioactive shear zone that strikes 

N. 55° W., dips 70° SW., and is 305 feet wide. Three similar zones, 

two of which are radioactive, are exposed southwest of the pit. The 

brecciated rock in the shear zone exposed by the prospect pit is cemented with barite, fluorite, and secondary copper minerals. Much 

of it is radioactive, and two samples taken from the dump contained 

0.12 and 0.14 percent U, although no uranium minerals were 

recognized.

Traverses made with a scintillation survey meter outlined a radioactive zone that trends eastward through the prospect pit for about 

300 feet across the structural pattern defined by the shear zones. The 

most radioactive areas occur where the shear zones are crossed by the 

radioactive zone. Because the radioactive zone apparently crosses 

structural trends and the Artillery formation is presumably quite 

thin at the Red Hills prospect, the extent of the deposit cannot be 

reliably predicted.

SUMMIT MINE

The Summit mine is in sec. 32, T. 23 N., R. 17 W., about 15 miles 

north of Kingman. It exposes a composite vein zone, 20 to 30 feet 

wide, which strikes about N. 40° W. and dips steeply northeast. The 

host rock is gneissoid biotite granite intruded by a few narrow mafic 

dikes.

The mine workings include drifts on 3 levels, entered by a 300-foot 

shaft and 2 crosscut adits. The shaft connects with drifts on the 160- 

and 300-foot levels, and 1 of the adits intersects the 160-foot level near 

the shaft. The other adit intersects the vein on the 500-foot level of 

the mine and connects with a 350-foot drift from which there is a 

30-foot raise.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-23

Lead, zinc, copper, gold, and silver minerals are present in the vein, 

but no uranium minerals were identified. The highest radioactivity 

detected came from material containing sooty chalcocite, which may 

be mixed with finely divided uraninite.

Significant radioactivity was detected only on the 500-foot level 

and in the raise above it, where traverses with a scintillation survey 

meter indicated the presence of a small amount of radioactive material 

in the exposed vein. The most radioactive areas are at the top of 

the raise and in a 20-foot exposure of the vein 130 to 150 feet southeast of the adit. Geiger counter readings at these places were as much 

as 20 times background radioactivity.

The radioactivity measurements indicate that it is unlikely that 

minable quantities of uranium ore are exposed in the workings examined. Selected specimens of the sooty material on the 500-foot level 

of the mine may contain 0.2 percent U or more, but only a very small 

amount of this material is present.

NAVAJO COUNTY 

ANNA BEKNICE CLAIMS

The Anna Bernice claims, N"os. 1 to 5 are 6 miles north of Joseph 

City; they were owned in 1951 by D. O. Roller of Wickenburg and 

L. W. Kowalski of Phoenix. The claims contain two shallow prospect pits dug in a thin lens of jasper enclosed in flat-lying bentonitic 

shale in the Chinle formation of Late Triassic age. The lens is about 

6 inches think and at least 150 feet in diameter. Most of it is exposed 

by the erosion of the overlying shale, so that it forms a small bench. 

The jasper is dark brown and shows relict fragmental structure. The 

darkest material seems to be the most radioactive. One specimen contained a few specks of a yellow uranium mineral on a fracture surface, 

but not enough of it is present to account for the uranium content of 

the deposit.

Three representative samples contained 0.025, 0.026, and 0.043 percent U, and a high-grade specimen contained 0.25 percent U.

Granger, who examined the property, believes that the uranium in 

the deposit may have been derived from the surrounding Chinle formation, a large part of which is now a montmorillonitic clay derived 

from volcanic ash. As the ash devitrified it lost silica, iron, uranium, 

and alkali metals; the silica and iron oxide selectively replaced a lens 

of conglomerate, forming an iron-rich jasper, and most of the uranium 

was redeposited in the jasper. The uranium, as determined from autoradiographs, occurs in extremely minute fractures invisible to the 

naked eye (T. G. Lovering, written communication, 1956).
A-24 CONTRIBUTIONS TO THE GEOLOGY OP URANIUM

PETRIFIED FOREST

PETRIFIED FOREST NATIONAL MONUMENT

During routine traversing by Granger with a carborne Geiger 

counter in March 1951, a small low-grade uranium deposit was found 

inside the southern boundary of the Petrified Forest National Monument. The deposit is exposed in a road cut on both sides of U.S. 

Highway 260, 1.1 miles west of the south gate to the monument.

Although the geologic map of Arizona by Barton and others (1942) 

shows this locality as being underlain by the Moenkopi formation, the 

varicolored shales and abundant petrified wood exposed there are 

more characteristic of the Chinle formation than of the Moenkopi, 

and the deposit is believed to be in the lower part of the Chinle.

The radioactive material is localized in fragmented carbonized 

fossil plants in a lens of sandy shale about 5 feet thick and more than 

125 feet across. Two representative channel samples contained 0.012 

and 0.015 percent U, but no uranium minerals were identified. An 

abundant powdery yellow material associated with the carbonized 

fossil plants and impregnating the enclosing rock is nonradioactive 

and appears to be an iron sulf ate.

TRACT NO. i

Tract No. 1, which covers 21 acres, was owned in 1951 by the New 

Mexico and Arizona Land Co. and leased to Frank A. DoBell of 

Holbrook. It is outside the Petrified Forest National Monument and 

extends along the west boundary, in the SE % sec. 1, T. 17 N., E. 23 E., 

about 3 miles west of the First Forest, in the northern part of the 

monument.

The uranium-bearing rock forms a lens about 125 feet long, exposed on both sides of a sharp ridge ; it has a maximum thickness of 

about 8 feet but thins rapidly to less than 2 feet. It is in flat-lying 

buff-colored sandstone, clay, and conglomerate of the Chinle formation of Late Triassic age which contain abundant carbonized and 

petrified fossil plant debris. The petrified material, which is commonly in the form of buff-colored tree limbs and trunks, is nonradioactive. All the radioactivity comes from the carbonized material. 

This consists mainly of fragments or small flattened lenticular masses, 

but some of the petrified tree limbs have an outer shell of radioactive 

carbonized wood, as though the limbs had been charred before burial 

in sediment. Perhaps the fragments of carbonized material represent charred twigs and bits of charcoal broken from the surfaces of 

burnt logs and limbs during deposition.

Two channel samples contained 0.008 and 0.017 percent U, and individual fragments of carbonized material are much richer. In gen-
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-25

eral, the radioactivity is roughly proportional to the amount of carbonized material. No uranium minerals were recognized.

TRACT NO. 2

Tract No. 2 covers 41 acres about 20 miles southeast of Holbrook. 

It is in the SE% sec. 33, T. 16 N., E. 23 E., about 3 miles south of 

the Petrified Forest National Monument. In 1951 it was owned by 

the New Mexico and Arizona Land Co. and was leased to Frank A. 

DoBell of Holbrook. The geologic map of Arizona by Darton and 

others (1924) indicates that Tract No. 2 is in the Moenkopi formation 

of Early and Middle( ?) Triassic age, but its rocks are more like the 

sandy clay and sandstone of the overlying Chinle formation, as exposed in the Petrified Forest National Monument.

A yellow uranium-bearing mineral, probably carnotite, coats fracture surfaces in the dull-brown petrified logs scattered over much of 

the tract. Whether this mineral was derived from a primary uranium 

mineral enclosed in the petrified wood or whether it came from some 

other source is not known. As a rule, the more colorful the petrified 

material the less radioactive it is.

Eepresentative samples from 2 of the logs contained 0.007 and 0.010 

percent U, but their radioactivity was equivalent to 0.018 and 0.014 

percent U, respectively, suggesting a significant amount of leaching.

PIMA COUNTY 

BLACK DIKE: DEPOSIT

The Black Dike deposit is on a group of five patented claims in 

sees. 23, 24, 25, and 26, T. 17 S., K. 10 E., on the west flank of the 

Sierrita Mountains and about 27 miles south-southwest of Tucson. 

The claims are on ranchland owned by Col. Moller of Tucson, who was 

leasing them in 1951 to Albert Ybarra, Glen Alien, and Bryce Wilson, 

all of Tucson.

The lower western slope of the Sierrita Mountains in the vicinity 

of the Black Dike claims is intricately cut by dry washes and has a 

rough rolling topography. Its average relief is less than 200 feet, but 

nearby hills and ridges rise as much as 400 feet above the surrounding 

surface.

The west flank of the Sierrita Mountains is composed of steeply 

dipping metamorphosed sandstone, limestone, shale, rhyolite, tuff, 

and conglomerate (Eansome, 1922). According to the geologic map 

of Arizona by Darton and others (1924), these metamorphosed sedimentary rocks consist largely of the Tornado limestone (Pennsylvanian and Mississippian) or Martin limestone (Devonian) and the 

Lower Cretaceous Comanche series. The core of the mountains is
A-26 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

largely composed of granite and granite gneiss. The bedded rocks 

either were partly granitized by hot solutions or were invaded and 

partly assimilated by a granite magma.

The mineral deposits on the west side of the Sierrita Mountains are 

mostly in limestone. Many of the deposits were developed before 

World War I, and during the war unrecorded but probably small 

amounts of lead, silver, and copper were produced. The ore minerals 

are sporadic and rarely form continuous ore bodies. The primary 

minerals include pyrite, chalcopyrite, argentiferous galena, sphalerite, 

argentite, cerargyrite, native gold, and, near the north end of the district, fluorite. Secondary minerals, which are common near the surface, include chalcocite, malachite, azurite, cerussite, anglesite, wulfenite, and, locally, psilomelane and pyrolusite. Kansome (1922) states 

that the metallization has not been strong and that the area probably 

does not contain any large ore bodies. The Black Dike deposit is 

developed by a shaft originally put down in search of copper, probably 

just before World War I. The shaft was unused for several years 

and was then back filled with waste material. Early in 1950, however, 

the remaining waste rock around the collar of the shaft was found by 

Albert Ybarra to be radioactive. Later in that year, K. J. Wright of 

the U.S. Atomic Energy Commission made a brief examination of the 

property, and at his suggestion the lessees began to reopen the workings in order to look for uranium. In March 1951 the shaft had been 

cleared to a depth of about 75 feet, but still contained an undetermined 

amount of backfill.

The deposit was examined in February 1951 by Granger and J. W. 

Adams. The area immediately surrounding the Black Dike shaft was 

mapped (fig. 6); the cleared part of the shaft was sketched in vertical 

section, and two plan views of the shaft were prepared (fig. 7). The 

location and uranium content of several samples collected in the shaft 

are shown in figure 7.

The Black Dike deposit is near the contact between the gneissic 

granite and the metamorphosed sedimentary rocks. The metamorphic 

rocks strike N. 0°-20° W. and dip steeply eastward. The major 

structural and topographic features are related to the trend of these 

rocks. The more resistant strata, such as silicified limestone, form 

discontinuous north-trending ridges. The Black Dike claims were 

named for a low ridge of micaceous schist that crops out just east of the 

shaft. The schist, which is intensely stained with iron and manganese 

oxides, was mistaken for a dike.

The Black Dike mine is in gneissic granite that is cut by a small 

intensely bleached and altered basalt (?) dike. The shaft was sunk 

in a copper-stained fracture zone. About 40 feet below the surface
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-27

EXPLANATION

Contact, approximately located

ea^ 

Strike and dip of foliation

 / 

Strike and dip of joints

kon-stained quartz vein,

showing dip 

Dashed where opproximote/x

Vertical iron-stained quartz vein

Dashed where approximately

located

Prospect pit

Dump

Geology and topography by H C Granger 

and J W. Adams. 1951

FIGURE 6. Geologic sketch map of the Black Dike deposit, Pima County, Ariz.

the shaft intersected the altered dike; this dike was followed as far 

down as the shaft had been cleared at the time of our visit in 1951. 

Both the hanging wall and the footwall of the dike have been locally 

mineralized.

The basalt(?) dike is irregular in thickness but averages about 2 

feet. Where observed underground, it strikes about N. 10° W. and 

dips 65° E., roughly parallel to the local foliation. The dike is highly 

altered and is concealed by rubble at the surface. In thin sections 

the dikerock shows a fine-grained texture similar to that of basalt. 

Most of the lath-shaped feldspar grains are altered to clay, and the 

ferro-magnesian phenocrysts are altered to chlorite. The dike locally 

contains calcite veinlets as much as an inch wide.
A-28 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

EXPLANATION

Pitchblende-bearing zone in granite

Back-filled waste rock

Approximate extent of contactmetamorphic minerals

Contact, showing dip

Dashed where approximately located

Fracture

Dashed where approximately located

PLAN

Sampled locality, showing

percent uranium 

B

FIGURE 7. Section and plans of the Black Dike shaft, Pima County, Ariz.

The dike is bordered by a very irregular contact-metamorphic zone 

in which the gneissic granite is altered to a finer grained schistose 

rock of greenstonelike appearance containing local concentrations of 

garnet, chlorite, and epidote, associated with pyrite, chalcopyrite, and 

magnetite (fig. 7). Fine-grained purple fluorite is disseminated 

through the greenstonelike rock and is commonly associated with the 

chalcopyrite. In some places the concentrations of garnet, chlorite, 

epidote, and sulfide minerals extend outward from the dike for several feet, but elsewhere the dike is in contact with the normal gneissic 

granite.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-29

The radioactive material is in those parts of the contact-metamorphic zone that are richest in sulfide minerals and fluorite. Radioactivity is highest along irregular fractures coated with a black sooty 

material that is probably a mixture of manganese oxide and pitchblende (Lamar Evans, U.S. Bureau of Mines, oral communication, 

1951). These fractures are mainly in the gneiss, but they extend, at 

most, only about 2 feet outward from the borders of the dike. In 

places they follow the contact, but none were observed within the dike.

Samples from the dike contained less than 0.006 percent U, but 

samples from the contact-metamorphic zone contained 0.011 to 0.16 

percent U. The samples also contained 0.01 to 0.97 percent copper, 

the lowest amounts being in samples from the dike.

Local concentrations of uranium minerals would probably be found 

by further exploration in the rocks bordering the dike, but no large 

deposit of high-grade uranium ore is likely to be discovered. Ransome's statements (1922) regarding weak metallization of the district 

probably applies to the uranium deposits as well as to the base-metal 

deposits.

Since the examination of the Black Dike deposit in 1951, some 

further mining has been done on the property. We do not know the 

results of the more recent work.

COPPER SQUAW MINE

The Copper Squaw mine is in sec. 36, T. 14 S., R. 2 E., about 2 miles 

east of Quijotoa. The uranium deposit is in breccia of a fault zone 

in altered andesite that is probably Tertiary in age. The fault zone 

strikes N. 50° E., dips 30° NW., and is 6 to 36 inches wide.

The mine workings on the property consist of a 110-foot shaft, inclined 30° NW., and 4 prospect pits. About halfway down the shaft 

the fault zone widens to about 3 feet and is well exposed in a stope. 

At the bottom of the shaft the zone is less than 1 foot wide.

Radioactivity in the stope is quite low, but selected material stockpiled near the collar was probably taken from the stope and is in part 

uranium bearing. The predominant uranium minerals are uranophane and uraninite. Associated ore minerals are malachite and 

sparse azurite and chalcocite. The gangue minerals are quartz, calcite, hematite, and limonite.

A sample representative of the stockpile contained 0.12 percent 

eU3O8. Two selected chip samples, taken from the ore body in the 

stope before it was mined out, contained 0.76 and 1.40 percent U3O8 

(R. L. Wells and H. E. Puttuck, written communication 1953). 

No other ore bodies have been found in the fault zone.
A-30 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

GLEN CLAIMS

The Glen claims are on the northwest flank of the Sierrita Mountains, in the NW^4 sec. 30, T. 17 S., E. 11 E., about 28 miles southsouthwest of Tucson, and about 1 mile east-southeast of the Black 

Dike deposit. In 1951 they were under lease to Albert Ybarra and 

Glen Alien of Tucson. The property is underlain chiefly by granite 

but partly by quartz-biotite schist. The radioactive material occurs 

in and along a breccia zone that strikes N. 20° W. and dips about 

80° SW. The breccia zone contains a silicified core about 6 feet wide, 

from which highly fractured rocks extend several feet on either side. 

The length of the zone was not determined, but it is radioactive for 

about 200 feet.

Near the northwest limit of radioactivity, an open cut about 15 feet 

long, 5 feet wide, and 6 feet in greatest depth exposes radioactive 

material along the hanging wall of the breccia zone. Most of the 

rock exposed in the cut is granite, but near the face there is a narrow 

vertical zone of light-colored intensely altered rock that contains much 

fine-grained muscovite or bleached biotite. The contacts of this rock 

with the granite are indistinct, and it is so easily weathered that it 

is not exposed at the surface. A 4-foot channel sample, which cuts 

2 feet of the altered rock and 2 feet of granite, contained 0.015 percent 

U, and its radioactivity was equivalent to 0.035 percent U.

In an exposure nearly 200 feet southeast of the opencut, the breccia 

zone is more highly radioactive. There the rock is silicified and has 

the appearance of aplite. It is iron stained, and pyrite is scattered 

along some of the fractures. A sample of this rock contains 0.027 

percent U, but its radioactivity is equivalent to 0.080 percent U. This 

lack of equilibrium indicates that the rock in the outcrops has been 

considerably leached and weathered and that uranium is probably 

more abundant in the fresh rock below.

IRIS ANI> NATALIA CLAIMS

The Iris and Natalia claims are in the SW1^ sec. 26, T. 21 S., R. 

11 E., in the Oro Blanco mining district. They were owned in 1951 

by Elmer and Lester Fernstrom of Tucson and Roman Encinas of 

Arivaca.

The several abandoned shafts and opencuts on the property explore 

three roughly parallel copper-bearing shear zones in rhyolite. Most 

of the mining was done on a shear zone several feet wide that strikes 

1ST. 80° E. and dips 34° N. Chalcocite nodules containing silver, gold, 

and uranium occur in gouge within the shear zone, especially along 

the footwall. These nodules may be related to the numerous ironstained quartz veins, apparently crosscutting the shear zone, that are 

exposed at the surface.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-31

Microscopic study of a specimen of radioactive material selected 

from the dump disclosed quartz, covellite, malachite, limonite, and 

a uranium mineral tentatively identified as kasolite. This specimen 

was reported (Wright, 1950) to contain 0.76 percent U3OS , but very 

little radioactive material could be found in the workings in 1951.

The owners reported that 2 diamond-drill holes collared north of 

the shaft intersected the low dipping shear zone at about 50 feet but 

that the drill cores contained no radioactive material and very little 

copper ore.

LENA NO. 1 AND GENIE NO. 1 CLAIMS

The Lena and Genie claims are in sees. 8 and 5, respectively, T. 

18 S., R. 11 E., on the west flank of the Sierrita Mountains and about 

25 airline miles southwest of Tucson. They are owned by M'anuel 

Obregon of Tucson.

On the Lena No. 1 claim, a shaft about 16 feet deep follows a radioactive fissure vein in a light-colored slightly foliated granite. In 

some places the granite contains irregular xenoliths of impure quartzite and consists of steeply dipping layers, of northwestward trend, 

which suggests that the rock may have been formed by granitization 

of quartzose sediments. Widely scattered dark-colored fine-grained 

dikes cut the granite in various directions, but most of them trend 

northwestward and dip southwestward.

The fractures in and near the Lena No. 1 claim also trend northwestward for the most part and dip steeply southwestward (fig. 8). 

This trend is roughly parallel to the banding in the granite. Along 

one of these fractures is a narrow vein, traceable for about 25 feet, that 

contains disseminated magnetite, pyrite, chalcopyrite, galena, and possibly sphalerite in a dense quartz gangue. Sooty pitchblende and 

kasolite(?) coat fracture surfaces, chiefly along the footwall side of 

the vein. These relations are evident only near the bottom of the shaf fe 

(fig. 9); near the surface the vein narrows and becomes a nearly unmineralized fracture which forms the hanging wall of a shattered 

zone about 3 to 4 feet wide. The granite of the shattered zone is 

argillized, partly silicified, and stained with hydrous iron oxides, and 

it contains sparsely disseminated pyrite and green copper minerals. 

It is most intensely altered alongside the pitchblende- and sulfidebearing vein, whose hanging wall is greenish tinged, possibly because 

of chlorite or serpentine, and silicified for about 3 inches from the vein.

The vein is about 1 to 2 inches wide at the bottom of the shaft and 

is apparently a fissure filling. The relative movement between opposite walls of the vein, if any, cannot be determined; therefore, the 

fracture may be a joint rather than a fault. Similar fractures nearby
A-32 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

EXPLANATION

Contact 

Dashed where approximately located

Fracture, showing dip

Dashed where approx

mately located

CONTOUR INTERVAL 10 FEET 

DATUM IS ASSUMED

Geology and topography by H. C. Granger 

and J. W. Adams, 1951

FIQUBE 8. Geologic sketch map of the Lena No. 1 claim, Plma County, Arlz., showing 

fracture pattern and uranium-bearing vein.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-33 

SW NE

.-.Surface

SECTION OF SOUTHEAST WALL OF SHAFT

MAP OF SHAFT

Contact, showing dip

Dashed where approximately

located

Fracture, showing dip

Dashed where approximately

located

t _ 0.012 ,

Sampled locality, showing 

percent uranium

Geology by H. C. Granger and J W. Adams, 1951 

10 FEET

FIGURE 9. Section and map of the discovery shaft, Lena No. 1 claim, Pima County, Ariz.

are tight and apparently contain no ore minerals. For those reasons 

it seems unlikely that the Lena claim contains any large ore body. 

Two channel samples cut across the shattered zone near the bottom 

of the shaft contained 0.004 and 0.012 percent U, and a grab sample of 

the vein filling contained 0.019 percent U. These contrast sharply
A-34 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

with a selected sample taken by the owner, which assayed over 2.0 

percent U, and a sample selected by Faick and Romslo ( J. N. Faick 

and T. M. Romslo, 1954, U.S. Defense Minerals Exploration Administration docket 3280) from the vein filling, which contained 0.25 

percent U3O8.

On the Genie No. 1 claim, a few hundred yards east of the Lena 

No. 1, very little anomalous radioactivity can be noted. The Genie 

deposit is very similar to the Lena deposit, but it has been even less 

deeply explored. The country rock is a light-colored granite that 

contains disseminated pyrite and abundant tourmaline. The tourmaline forms clusters of radiating crystals in the granite, and some veins 

as much as 4 feet wide consist almost entirely of quartz and tourmaline. Most of these veins dip steeply southwestward.

Radioactivity is highest in the altered rock adjacent to a fracture 

in granite exposed along a draw, which crosses both claims. The fracture strikes about N. 40° W. and is nearly vertical. No uranium 

minerals or sulfide minerals were seen in this rock, but a sample contained 0.004 percent U and showed radioactivity equal to 0.008 percent 

U. A fracture along the southwest wall of one of the tourmalinebearing veins also showed weak radioactivity, about 5 times the normal 

or background reading, but this radioactivity is apparently unrelated 

to the tourmaline.

SURE FIRE NO. 1 CI/AIM

In August 1949, material of abnormal radioactivity was discovered 

on the Bar-LY Ranch in sec. 15, T. 13 S., R. 18 E., about 30 miles 

east-northeast of Tucson, and the Sure Fire No. 1 claim was located 

on the radioactive material by Dominick Oberto and others of Tucson. 

Four shallow prospect pits were sunk on the property, but no further 

work was done until 1954 when, after this report was written, there 

was renewed exploration.

The rocks on the Sure Fire No. 1 claim are believed to be of Precambrian and Cambrian ages. Apparently the oldest rock is a graygreen schist, consisting chiefly of quartz and chlorite interlaminated 

with dark minerals. The foliation dips 25°-55° NE. This rock may 

belong to the Final schist of Precambrian age. Probably intrusive 

into the schist, and nearly concordant with its foliation, is a gneissic 

granite that may be related to the Oracle granite, which is described 

by Moore, Tolman, and others (1949) as a coarse-grained nearly white 

rock with large feldspar phenocrysts that is locally crushed and contains schlieren. The granite and schist are successively overlain on 

the ridges by rocks that probably represent the Bolsa quartzite and 

the Abrigo limestone, both Cambrian in age. Fine-grained dark-
RECONNAISSANCE OP URANIUM DEPOSITS IN ARIZONA A-35

colored dikes cut the Precambrian rocks on this claim and cut the 

younger rocks in nearby areas. The dikes are hard to trace on the 

surface, but where exposed they show both concordant and discordant 

relations to the foliation of the granite and schist.

All four shallow prospect pits on the Sure Fire No. 1 claim all are 

along an arroyo draining southward. These will be designated as pits 

A, B, C, and D.

Pit A, on the east side of the arroyo and about 30 feet above its floor, 

exposes weakly radioactive altered and iron-stained schist that contains a few veinlets of purple fluorite. A 14-foot chip sample of the 

schist just below pit A contained only 0.002 percent U, though its 

radioactivity would indicate 0.006 percent U.

Pit B, an opencut on the east wall of the arroyo about 60 feet northwest of pit A, exposes a bed of gray platy quartzose schist that is 

radioactive. The radioactive schist is locally crushed and altered and 

contains very small veinlets of quartz, fluorite, and calcite. It is overlain by dull gray-green schist that is soft and apparently chloritic.

A zone of abnormal but very weak radioactivity seems to be continuous between pits A and B. Across the arroyo from pits A and B is 

a small area of weakly radioactive schist that has not been explored 

by the owners. The radioactivity is largely in float; little bedrock 

can be seen.

Pit C, which lies north-northwest from pit B, is in a crushed and 

fractured zone, 8 feet wide, in altered gneissic granite. The Blue 

Rock shaft, sunk after our examination of the property, is probably in 

this zone. The granite contains veinlets and breccia fillings of quartz, 

calcite, purple fluorite, and an unidentified white claylike material. 

Some of the fractures contain yellow uranium minerals, identified as 

uranophane and autunite by the U.S. Bureau of Mines in Tucson. The 

crushed granite is iron stained, and pyrite and chalcocite are disseminated through slightly altered rock bordering the crushed zone. 

The radioactive material shows no continuity of trend. A 4-foot 

channel sample across the middle of the crushed zone showed radioactivity equivalent to 0.13 percent U but contained only 0.008 percent 

U by chemical assay.

Pit D, about 170 feet north of pit C, is in fractured schist along the 

west side of the arroyo. The two most prominent fractures strike 

N. 85° E. and N. 60° V., and dip 80° N. and 75° NE., respectively. 

They are about 4 feet apart in the face of the pit, and between them 

are veinlets filled with purple fluorite. The most radioactive material 

is a dull black coating on fracture surfaces. No uranium mineral has 

been identified in this material, which is far out of equilibrium; the 

radioactivity of 2 channel samples that contained only 0.004 and 0.006-
A-36 CONTRIBUTIONS TO THE GEOLOGT OF URANIUM

percent U was equivalent to a uranium content of 0.069 and 0.038 

percent.

The radioactive zones are weak and discontinuous, and all appear 

to be elongate parallel to the foliation. Weak abnormal radioactivity 

is traceable for the 60 feet between pits A and B, but pit G and pit D 

seem to be in 2 separate radioactive zones, both less than 25 feet long at 

the surface. All 3 radioactive zones contain minor amounts of purple 

iluorite, but the fluorite itself is not abnormally radioactive. The 

^ones have been intensely leached, and their uranium content should 

increase downward for at least a few feet.

VAN HILL, NO. 5 CLAIM

The Van Hill No. 5 claim is on the northeast flank of the Kincon 

Mountains, in sec. 15, T. 13 S., E. 18 E., about 30 miles east-northeast 

of Tucson. It was owned in 1951 by E. M. Vanover and others of 

Tucson.

Kadioactive material is found in an altered quartzite, probably of 

Cambrian age, underlain by Precambrian metamorphic rocks and overlain by Paleozoic limestone. The quartzite is cut by a radioactive 

iracture zone, about 4 feet wide, that is traceable for about 50 feet; 

radioactivity is most intense where the fracture zone is exposed in an 

arroyo. In the fracture zone the quartzite is stained with iron and 

manganese minerals and contains fine-grained ferromagnesian minerals. A prospect pit in the bottom of the arroyo was almost completely filled with sand and gravel at the time of the examination. A 

few feet below the surface a yellow uranium mineral, probably autunite, is associated with purple fluorite in the fractures.

Analysis of a grab sample indicated that the uranium is not in equilibrium: the sample contained only 0.008 percent U, but contained 

0.17 percent ell. The deposit has been strongly leached at the surface, 

and if the lack of equilibrium is the result of leaching, the uranium 

content may increase with depth.

VAN HILL NOS. 7 AND 8 CLAIMS

The Van Hill Nos. 7 and 8 claims are in the NW*4 sec. 24, T. 13 S., 

U. 18 E., about 30 miles east of Tucson and 1.5 miles south-southwest 

of the Bar-LY ranchhouse. (See U.S. Geological Survey 15-minute 

topographic map of the Redington, Ariz., quadrangle, 1943.) The No. 

7 claim was located by E. M. Vanover and the No. 8 claim by L. D. 

Hill, both of Tucson.

The uranium concentration on these claims are in a conformable 

sequence of generally thin-bedded limestone, shale, and conglomerate 

.strata that strike N. 40°-60° W. and dip 45°-70° NE. The rocks are
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-37

probably of late Paleozoic age and may belong to the Naco limestone of 

Pennsylvanian age. The radioactive zone, exposed just below the crest 

of a short ridge formed by resistant limestone, follows a petroliferous 

limestone bed as much as 2 feet thick (fig. 10). Radioactivity 

commonly extends into the overlying fine-grained limestone and the 

underlying iron-stained shaly limestone, so that the maximum thickness of radioactive rock is about 6 feet. The radioactive zone is in 

2 segments, one 115 and the other 190 feet long, separated by 28 feet 

of nonradioactive limestone. The northwest segment appears to be 

slightly higher stratigraphically than the southeast segment, possibly 

because of the lenticularity of the strata.

Outcrop of radioactive shale and limestone 

in a conformable sequence of thinbedded limestone, shale, and conglomerate

0.012

Upper figure, width in feet, of chip channel 

sample; lower figure, percent uranium in 

sample

~^50

Strike and dip of beds

Geology and topography by H C Granger 

and J.W.Adams. 1951

FIGURE 10. Diagram outlining the radioactive rocks on the Van Hill Nos. 7 and 8 claims,

Pima County, Ariz.

The uranium content of 3 samples taken across the radioactive zone 

ranged from 0.011 to 0.021 percent; it is not far out of equilibrium, 

which indicates that the limestone has not been appreciably leached. 

No uranium minerals were recognized, but the petroliferous material is 

the most radioactive.
A-38 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

FINAL COUNTY 

HONEY BEE NO. 4 CLAIM

The Honey Bee No. 4 claim is about 2 miles southwest of Kelvin, in 

sec. 16, T. 4 S., E. 13 E., and was owned in 1951 by Leo Wall of Eay 

and I. D. Hollenbeck of Kelvin. It was originally worked for copper, 

but the copper deposits are not radioactive. Eadioactivity is associated with a shattered fine-grained mafic dike, about 4 feet wide, 

and a nearby porphyry dike, each cutting the granite country rock. 

The petrographic classification of these dikes was not determined.

A 2-foot zone of iron-stained rock along the hanging wall of the 

mafic dike is radioactive in places for nearly 200 yards. A selected 

grab sample contained 0.021 percent U; the average uranium content 

is probably even lower.

The porphyry dike is radioactive in places for about 200 feet; one 

place indicated radioactivity of 0.4 mr per hr on a portable Geiger 

counter, where normal background was about 0.04 mr per hr. The 

dike is iron stained, and the uranium may be associated with the iron 

oxides.

SHORTY CLAIMS

The Shorty Nos. 1, 2, and 4 claims are in sec. 15, T. 4 S., E. 13 E., 

about 3 miles southwest of Kelvin. They were owned in .1951 by Leo 

Wall and Eay Adams of Eay and I. D. Hollenbeck of Kelvin. The 

country rock on the claims is a coarse-grained locally porphyritic 

granite. The radioactive material is associated with quartz stringers 

and oxides of iron and manganese in broad shear zones; the wallrocks. 

commonly contain products of argillic alteration. The shear zones 

are about 3 feet to 100 feet wide and are traceable for several hundred 

yards, but the radioactivity is sporadic. The zones on the No. 1 and 

No. 2 claims strike N. 55°-85° W. and are nearly vertical; those on 

the No. 4 claim strike N. 45° W. and dip 65° NE. The radioactive 

parts of the shear zones are explored by several prospect pits and an 

adit about 15 feet long.

No samples were taken, but the radioactivity was about 2 to 5 times 

the normal background reading and probably equivalent to less than 

0.01 percent U.

WOOLEY NO. 1 CLAIM

The Wooley No. 1 claim is about 5 miles southwest of Kelvin, in 

sec. 33, T. 4 S., E. 13 E., and was owned in 1951 by Leo Wall of Eay 

and I. D. Hollenbeck of Kelvin. It was originally explored for copper by a 250-foot shaft. An unknown tonnage has been mined, largely 

from a resistant quartz-filled breccia zone that contains malachite, 

chalcopyrite, and, perhaps, chalcocite. This material is not appreciably radioactive.
RECONNAISSANCE OF UEANIUM DEPOSITS IN ARIZONA A-39

Although the material mined is not radioactive, the claim contains 

at least three veins that are radioactive. These cut the coarse- to 

fine-grained granite and are exposed within 150 yards of each other 

along a draw below the copper workings. They strike N. 63°-85° E. 

and dip 70°-90° SE. For convenience they will be termed veins 1, 2, 

and 3. Vein 1 is less than 1 inch wide but is bordered by a zone, up 

io 3 feet wide, that is characterized by argillic alteration products, a 

little silicified rock, and iron stains. It also is slightly copper stained. 

Its radioactivity is twice the normal background. Vein 2 is oneeighth to 3 inches wide, contains chrysocolla, and its radioactivity is

2 to 3 times more than the normal background. Vein 3 is developed 

by a 100-foot adit along a shear zone formed by a series of fractures 

.and stringers 3 to 4 feet apart. Much of the rock in the shear zone is 

copper stained. A selected sample from the adit contained 0.017 

percent U.

SANTA CRUZ COUNTY 

ANNIE IjAUBIB CLAIMS

The Annie Laurie claims cover a lead-zinc-uranium prospect in the 

SE14 sec. 1, T. 23 S., R. 11 E., about 25 miles west of Nogales and

3 miles south of the nearly abandoned mining town of Ruby. They 

were owned in 1951 by J. H. Bright, Jr., of Tucson, who discovered 

radioactive material on the Annie Laurie prospect (fig. 11) in the 

summer of 1948, when he tested a calcareous-tufa spring deposit with 

a Geiger counter (Wright, 1951). A small excavation, pit F on 

figure 11, failed to reveal any uranium minerals, but other pits on 

the hillside above the tufa disclosed two abnormally radioactive areas. 

Pit C contained some secondary uranium minerals; pit A exposed 

pitchblende and metallic sulfide minerals in a carbonate gangue. 

Other shallow prospect pits were dug, but all were in barren rock 

except pit B, which exposed minor amounts of sulfide minerals in a 

carbonate gangue. A 100-foot hole was diamond drilled in 1952, but 

no information about it is available because the core was not logged 

and was not properly saved.

The uranium deposits on the Annie Laurie claim are largely in 

granite, close to small bodies of porphyry, probably andesite, near the 

contact between granite and sedimentary rocks (figs. 11, 12). The 

granite, which appears to form a stock, is fine grained and is white to 

pink, owing to various proportions of white and red feldspar. The 

porphyry was injected along parts of the contact between the granite 

and the sedimentary rocks as an irregular dike, but dikes and sills of 

this rock also occur in the sedimentary strata, and lobes of it extend 

into the granite. The sedimentary rocks are interstratified shale, 

limestone, grit, and conglomerate, probably younger than Paleozoic in
A-40 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

EXPLANATION

Contact, showing dip>

Dashed where opproxirnateiy heated

Fault, showing dip 

Dashed where approximately located

Fault surface

*&

Breccia

Quartz filled and highly 

iron stained

Shear fractures, 

showing dip

Strike and dip of beds.

O

Uranium prospects.

x 

Older prospects

CONTOUR INTERVAL 10 FEET 

DATUM IS ASSUMED

Geology and topography by H. C. Granger 

and J. W. Adams, 1951

FIGURE 11. Geologic map of the Annie Laurie prospect, Ruby district, Santa Cruz 

County, Ariz. Sections along lines A-A' and B-B' are shown in figure 12.

age. They are essentially flat lying, but near the intruded igneous 

rocks they are jumbled and are tilted as much as 20°.

The most significant feature related to the localization of the uranium is probably a system of north-trending east-dipping faults. 

These faults are roughly parallel to the margin of the granite and 

nearly parallel to the slope of the hillside; a large area of fault surface 

is exposed near pit B. Several of the fault fissures contain breccia 

cemented with porous quartz. The pores in the quartz probably 

once contained calcite, which has since been removed by weathering. 

Irregular zones of silicified breccia are exposed in the granite within 

the fault zone. The faults are younger than the porphyry.

North of pits A and B is a well-defined zone of shear fractures that 

strikes N. 60° W. and dips steeply northeast. Other fractures of
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-41

FEET 

250 n

200-

EXPLANATION

Granite

Sedimentary rocks

Sandstone, grit, and

conglomerate

Contact

Dashed where approximately located

Fault

Dashed where approximately located

DATUM IS ASSUMED

FIGURE 12. Geologic sections, Annie Laurie prospect, Ruby district, Santa Cruz County, 

(Ariz. Section lines are shown in figure 11.

similar attitude are common near the deposits but do not form such 

a prominent shear zone. Those exposed in the pits are locally filled 

with limonite.

Alteration in the vicinity of the uranium deposits was characterized by weak to strong silicification and by green coloration of the 

feldspar in the granite. Intense silicification commonly obscured 

the textures of the igneous rocks, so that the granite is nearly indistinguishable from the porphyry.

Within the alteration zone near the north-trending faults are many 

small variously oriented irregular veins, rarely more than 

3 or 4 inches thick and 3 or 4 feet long. The walls of the veins are
A-42 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

generally green, probably from chloritic alteration, and the original 

minerals are partly replaced by carbonate minerals, quartz, and a little 

pyrite. The vein filling is predominantly calcite but includes small 

amounts of sulfide minerals and quartz. Sphalerite, galena, chalcopyrite, pyrite, and purple fluorite form blebs and stringers in the calcite 

gangue. At some places in the wider veins the sulfide minerals, especially sphalerite, are concentrated in two layers within the calcite and 

parallel to the vein walls, as though the deposition of calcite had been 

interrupted by a period of sulfide deposition. Uraninite locally occurs 

disseminated and in hairline fractures in the walls of the veins, but 

none was noted within the vein filling.

Samples taken at pits A, B, and C contained 0.010, 0.015, and 0.010 

percent U, respectively. Two samples taken at pit F contained 0.015 

and 0.010 percent U, nearly in equilibrium with its daughter products; the first of these 2 samples consisted of a calcareous tufa and 

the second of underlying pyrite-rich sedimentary rocks. Wright 

(1951) lists assays as high as 0.79 percent U, but these were of selected 

material on the dumps.

The pitchblende and sulfide minerals appear to have been deposited 

by hydrothermal solutions that circulated along the north-trending, 

east-dipping fault fissures. Only quartz and calcite are now found 

in these fissures; the ore minerals occur only in and near related 

fractures bordering the faults. It is possible, however, that pitchblende and sulfide minerals were deposited in the fault fissures but 

were leached from them near the surface. If this is true, ore minerals 

might be found in the fissures by further exploration below the zone 

of weathering. The radioactive calcareous tufa at pit F was probably formed by leaching of the breccia and movement of ground water 

along the N. 60° W. set of fractures.

An article by Anderson and Kurtz (1955) describing a biogeochemical reconnaissance of the Annie Laurie prospect was published 

after our examination was made.

WHITE OAK PROPERTY

The White Oak property is in the NE% sec. 2, T. 24 S., R. 12 E., 

15 miles northwest of Nogales. The host rock of the deposit is 

rhyolitic volcanic rock of Cretaceous or Tertiary age. The deposit is 

in a mineralized shear zone from which oxidized lead ore was mined.

The mine workings all follow or intersect the shear zone and consist 

of the White Oak adit, the White Oak No. 1 adit (fig. 13), 4 smaller 

adits, and several surface cuts and pits. The drift entered by the 

White Oak adit has been stoped for almost the entire length of the 

part that is accessible ; the adit has been blocked by caved rock about
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-43

Ktr

EXPLANATION

Rhyolitic volcanic rock.

o <

a: 

o

Fracture, showing dip 

Dashed where approximately located

Mineralized fracture, showing dip

Uranium bearing

^

SECTION THROUGH WINZE

Raise 

(caved)

Geology by R. B. Raup, 1952

FIGURE 13. Map of part of the White Oak No. 1 adit, Santa Cruz County, Ariz.

350 feet from the portal. The White Oak No. 1 adit cuts across to 

the shear zone beyond the caved area. Raises and winzes connect the 

various workings of the mine.

The mineralized shear zone on the White Oak property strikes 

about N. 55° E.; its dip ranges from 70° SE. to vertical and averages 

80° SE. The few exposures on the surface and in the mine workings 

indicate that this shear zone extends for at least 1,500 feet across the 

property. It is a complex zone, as much as 30 feet wide, consisting 

of sheared, fractured, and locally shattered rock. In. places it con-
A-44 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

tains as much as 3 feet of breccia and gouge in a zone of intense 

shearing near the middle. Cerussite, the mineral originally sought 

by the owners of the property, fills fissures and partly replaces the 

breccia and gouge.

Uranium minerals have been found in the White Oak No. 1 adit 

(fig. 13), principally at its intersection with the mineralized shear 

zone. They are most abundant in 2 narrow intersecting zones of 

fractures, which are as much as 10 inches wide, within the shear zone; 

the rock between the fracture zones contains very little uranium. 

The uranium minerals are chiefly kasolite and uranophane, but they 

include small amounts of dumontite, autunite, and, perhaps, uraniumbearing pyromorphite. These minerals, all dark-yellow or orange, 

commonly occur as earthy or hard incrustations on the walls of 

fractures.

Selected samples from the uranium-bearing fractures in the White 

Oak No. 1 adit contained as much as 0.82 percent U, and a chip sample 

across a 10-inch fracture zone contained 0.47 percent U. Concentrations of such "high-grade" material, however, are small, discontinuous, and rare.

YAVAPAI COUNTY 

ABB LINCOLN MINE

The Abe Lincoln mine is in the SEV4 sec. 11, T. 8 N., E. 3 W., about 

14 miles by road northeast of Wickenburg. A limited partnership 

known as The Abe Lincoln Mines owned the property in 1952. The 

mine was opened in 1917 as a copper prospect and has produced a 

small amount of copper ore.

The mine has 2 vertical shafts and 2 adits, connected with 3,150 feet 

of drifts and crosscuts. Although both shafts are inaccessible because 

of water and caved rock, Elsing and Faick (M. J. Elsing and 

J. N. Faick, 1952 Defense Minerals Production Administration 

docket 2331) report that mine records indicate that 1 shaft was sunk 

660 feet and gave access to workings on the 145-, 175-, 350-, and 660- 

foot levels and that another was sunk 175 feet to connect with the 

350-foot level. One adit follows the Abe Lincoln vein system on the 

175-foot level for at least 350 feet to a point beyond which it is caved. 

The other adit cuts across to the drift on the 145-foot level but is 

partly caved at the portal and is completely blocked 160 feet from the 

portal.

The country rock is a gneiss and schist complex of Precambrian 

age, locally intruded by Precambrian tourmaline granite and by 

younger dikes of both felsic and mafic composition, which cut both 

the metamorphic rocks and the granite. As indicated by the strikes
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-45

of the dikes, the predominant structural trends in the vicinity of the 

mine are N. 50° E. and N. 32°-45° W.

The Abe Lincoln vein system consists of two veins separated by 

a narrow basalt dike; all three are on the hanging-wall side of a 

trachyte porphyry dike, and they, together with the trachyte porphyry 

dike, occupy a fault zone that strikes approximately N. 50° E. and 

dips 78°-89° NW. The vein on the footwall side of the basalt dike 

ranges in width from a few inches to 5 feet; the other vein, on its 

hanging-wall side, is narrower. Slickensided gouge, from 1 to 18 

inches thick, is common between the basalt dike and the footwall 

vein. The dikes are older than the ore, for they contain sparsely 

disseminated ore minerals.

The veins contain chalcopyrite and smaller amounts of azurite, 

chalcocite, and malachite, in a gangue of quartz, calcite, pyrite, and 

limonite. On the dump there is some purple fluorite associated with 

calcite, but no fluorite was noted in place in the exposed vein system.

No radioactive material was found in place in the 510 feet of accessible mine workings, but uranium minerals were found in small 

amounts on the dumps of the 660-foot shaft and the 145-foot level 

adit. Selected samples from the dumps contained as much as 0.46 percent U. The material from the shaft dump included trachyte porphyry containing fractures coated with malachite, limonite, and 

secondary uranium minerals; it also included vein material consisting 

of chalcopyrite, malachite, secondary uranium minerals, and fluorite 

in a gangue of pyrite, quartz, calcite, sanidine, and black altered 

gouge. The gouge contains disseminated grains of pyrite and chalcopyrite in a fine-grained aggregate of chlorite, sericite, altered feldspar, 

quartz, apatite, and leucoxene( ?). The material from the adit dump 

included a large specimen of banded vein filling that consisted of 

quartz, black altered gouge, sanidine, pyrite, chalcopyrite, and secondary uranium minerals. The principal secondary uranium mineral 

in this specimen was identified by X-ray methods as schoepite. It 

formed a coating on pyrite grains.

Although no primary uranium minerals were identified, the presence 

of uraninite is suggested by the secondary uranium minerals, especially schoepite, for schoepite occurs as an alteration product of uraninite in the Belgian Congo (Palache, Berman, and Frondel, 1944, p. 

628) and at Beryl Mountain, N.H. (Rabbitt, 1953). Finely divided 

uraninite may be present in the black altered gouge, which is weakly 

radioactive in many specimens from the dumps.

As no significant radioactivity was detected in the accessible mine 

workings, the source of the radioactive material on the dumps could 

not be determined. This material is unlike that known to come from
A-46 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

the Abe Lincoln vein system, the most noticeable difference being the 

fluorite in the calcite gangue. Perhaps the uranium-bearing rock on 

the dumps came either from local fluorine-rich pockets in the Abe 

Lincoln vein system, or from some other vein, separate from or intersecting the main system.

Samples from a vein on a property about a mile west of the Abe 

Lincoln mine contained 0.006 and 0.012 percent U and a sample that 

contained 0.012 percent U was taken from an exposure of the metamorphic rocks in a road cut a little less than a mile west of the mine. 

Although these samples do not in themselves contain much uranium, 

they indicate that the area around the Abe Lincoln mine may contain 

minable deposits of low-grade uranium ore.

CUBA AND INDEPENDENCE CLAIMS

The Cuba and Independence claims are adjacent to one another in 

T. 11 N"., R. 5 W., approximately 7 miles north-northwest of YarnelL 

On the Cuba claim there is an 18-inch quartz vein, striking N". 52° W. 

and dipping 25° NE., in a coarse-grained buff-colored granite. The 

mine workings comprise a 125-foot inclined shaft connecting with a 

150-foot adit drift. For about 25 feet along the drift, flecks of what 

seems to be torbernite occur sparingly in a narrow zone on the f ootwall 

side of the vein. A chip sample across this zone contained 0.009 percent U.

Within a hundred yards of the Cuba workings and on the Independence claim, a thin coating of uranophane ( ? ) was found on an 

exfoliation surface in the coarse-grained granite country rock. A 

selected sample of the material contained 0.016 percent U. The country rock in the vicinity is abnormally radioactive, though not uniformly so. As measured with a scintillation survey meter, the 

background radioactivity was 0.015 to 0.020 mr per hr and the radioactivity of the granite ranged from 0.035 to 0.140 mr per hr. The 

highest readings were obtained at the exfoliation surface ; the average 

reading was between 0.040 and 0.050 mr per hr. A representative 

sample of the granite contained 0.004 percent eTJ.

KITTEN NO. 1 CLAIM

The Kitten No. 1 claim is in the SW% sec 27, T. 15 K, R. 9 W., about 

155 feet west of the Hillside mine road and 4.3 miles from Bagdad. 

It was owned in 1951 by W. D. Moore of Bagdad. The country rock 

in the area is a coarse-grained porphyritic granite, of Precambrian 

age, cut by many narrow pegmatite and aplite dikes. Most of the 

dikes are roughly parallel to the most prominent joints, which strike 

N. 23° W. and dip 85° NE. Development in 1951 consisted only of one 

shallow prospect pit.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-47

The uranium deposit extends along a fracture that strikes N. 88° W. 

and dips 60° K, at a large angle to the regional structural trend, and 

that forms a well-defined footwall for the deposit. Metatorbemite, 

pyrite, and fluorite are disseminated in a zone of intensely altered rock 

3 to 4 feet wide. Within this zone most of the feldspar is changed to 

clay, yet most of the biotite retains its original form and luster. Much 

of the altered material, and the minor fractures bordering the hanging wall, are intensely iron stained. The deposit is only about 15 feet 

long at the surface, and probably is shallow. The footwall fracture 

is traceable for about 50 feet, being marked by a narrow quartz filling 

and limonite stain. Several nearby fractures have the same attitude 

and contain minor amounts of quartz and limonite, but they are not 

radioactive.

Two channel samples across the most radioactive part of the deposit 

contained 0.094 and 0.013 percent IT. The first sample seems to have 

been strongly leached, for its radioactivity was equivalent to 0.20 

percent U.

The relation of this deposit to other uranium deposits in the area is 

not known. The deposit is only about 3 miles from the Hillside mine 

from which uraninite has been identified, but there is no reason to believe that the two occurrences are closely related.

PEEPLES VALLEY MINE

The Peeples Valley mine is in the Weaver Mountains, about 20 

miles southwest of Prescott. Its workings consist of a 20-foot shaft 

and several opencuts. The deposit is in a ]enticular mass of quartzfeldspar pegmatite in coarse-grained granite. The pegmatite strikes 

about N". 40° E. and dips from 70° NW to nearly vertical. Its outcrop is about 300 feet long and 150 feet wide.

In 1953 a small amount of scrap mica was produced from the mine. 

In addition to numerous though small books of muscovite, the pegmatite contains small quantities of beryl and probably niobium-tantalum 

minerals. Although assays indicate the presence of uranium and 

thorium, no primary radioactive minerals were identified. The uranium occurs in yellow secondary minerals, predominantly uranophane, 

and possibly also in niobium-tantalum minerals.

Three samples obtained from the few small concentrations of radioactive material in the mine contained 0.004 to 0.13 percent U and 

0.032 to 0.078 percent Th. A selected sample from the most radioactive spot in the mine contained both the most uranium and the most 

thorium.
A-48 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

YUMA COUttTY 

ATOM CLAIMS

The Atom Nos. 1,2, and 3 claims were located for uranium by Richard Peters of Yuma in the fall of 1948. They are near the intersection 

of the U.S. Coast and Geodetic Survey coordinates 1099100 N. and 

83900 E. on the Picacho 15-minute quadrangle map.

The country rock is a medium-grained foliated Precambrian granite 

containing lenticular inclusions of mica schist, the largest of them 

several hundred feet long. The elongation of the inclusions, like the 

regional foliation, strikes about N. 55° W. and dips 55° SW., but the 

strike and dip show extreme local variations. The principal joints 

strike Nw 15° W. and dip steeply eastward. The schist inclusions commonly have hematite veins along their footwall contact, and parts of 

these veins are very weakly radioactive. Barren quartz veins occur in 

small swarms and locally follow the principal joints.

A 25-foot inclined shaft on the Atom No. 1 claim follows the foliation, which there strikes N. 40°-45° W. and dips 40°-60° SW. The 

shaft was sunk in fractured rock that appears to be schist partly assimilated by the enclosing granite. Along the foliation are stringers 

of quartz, hematite, and calcite. Some weak radioactivity, probably 

associated with the hematite, was found in the shaft.

Other radioactive zones on the Atom claims are exposed in shallow 

prospect pits. There also the radioactivity is commonly associated 

with hematite-rich stringers, which follow either the foliation in schist 

inclusions or the principal joints. No uranium minerals were recognized in either the shaft or the pits.

Samples taken by the owner contained 0.01 to 0.04 percent U. As 

the samples indicate that the uranium is in equilibrium and there is 

no evidence of strong mineralization, it seems unlikely that the deposits will improve in grade at greater depth.

MCMIULAN PROSPECT

The McMillan prospect is on the northwest flank of the Cabeza 

Prieta Mountains, 25.5 miles southeast of Wellton on the road between 

Wellton and Tule Tank. The deposit is in a fracture zone that strikes 

N. 34° W. and dips 68° SW., in biotite granite. The zone is traceable for 210 feet up a 30° slope and along the crest of a ridge. Adjacent to the fracture zone is a quartz-feldspar pegmatite dike that 

roughly parallels the zone on the hanging wall side. Two short adits 

and an opencut have been driven into the fracture zone where it is 

exposed on the slope. The lower adit is about 10 feet long and the 

upper adit, 90 feet up the slope, is about 20 feet long. The opencut, 

which is 110 feet above the upper adit and near the top of the slope, is
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-49

only 5 feet long. At the lower adit stringers of pegmatite are about 

2 feet above the hanging wall of the fracture zone. These stringers 

merge upward into a pegmatite dike 4 to 5 feet wide. The distance 

between the fracture zone and the pegmatite gradually decreases upward, and from the upper adit to the opencut the pegmatite forms the 

hanging wall of the zone. The fracture zone is about l1/^ feet wide 

at the lower adit, but it narrows upward, being only about 2i/£> inches 

wide at the opencut.

Where exposed in the lower adit, the fracture zone is stained along 

the cracks by copper and iron minerals, and there are seams of malachite and chrysocolla along major fractures. Chrysocolla and malachite occur in a similar way at the upper adit and in the opencut, but 

in those openings the copper and iron stains are stronger than in the 

lower adit. The pegmatite is fractured and copper- and iron-stained 

where exposed in the opencut, but not in the two adits. Apparently the 

metalliferous solutions followed the fracture zone and are not related 

genetically to the pegmatite.

A 50-foot vertical shaft a short distance northwest of the adits does 

not seem to be in this fracture zone, even though it is in highly fractured and iron-stained granite whose larger fractures are coated with 

secondary copper minerals.

At some places in the mine workings and on the dumps, radioactivity is as much as five times the background radioactivity. A stockpile of copper-stained material presumably mined from one of the 

adits gave readings of nearly 0.5 mr per hr on a scintillation meter. 

A selected sample of this material contained 0.034 percent U 

and 7.69 percent copper. Although it is possible that the McMillan 

prospect contains local concentrations of uranium ore, most of the 

radioactive rock on the property is below commercial grade.

CONCLUSIONS

Some of the deposits described in this report deserve more detailed 

geologic study and physical exploration. Further work has in fact 

been done on the deposits in the Dripping Spring quartzite since the 

completion of fieldwork on which this report is based, and some exploration has been conducted on the Annie Laurie claims. The Orphan claim and Hack's mine contain deposits of the same type, and 

the similarity in geologic setting seems too great to be accidental; 

further study of these would increase the possibility of finding other 

similar deposits on the Colorado Plateau. In fact, since this part of 

the report was originally written, Western Gold and Uranium, Inc., 

has extensively mined the Orphan claim, has explored the Hack Can-
A-50 CONTRIBUTIONS TO THE GEOLOGY OF URANIUM

yon deposit, and has discovered similar structural features in the 

Grand Canyon region.

The source of the uranium-bearing rock on the dumps of the Abe 

Lincoln mine cannot be determined until the caved workings have 

been, at least in part, reopened. The dumps on which radioactive 

material was found are at the collar of the 660-foot shaft and the 

portal of the 145-foot-level adit. As the shaft is caved for 175 feet 

below the surface (M. J. Elsing and J. N. Faick, 1952, Defense Minerals Production Administration docket 2331), the 145-foot-level adit, 

though now partly caved at the portal and completely caved 160 feet 

beyond it, might be the more economical way to reenter the mine. Although only a little uranium-bearing rock was found on the dumps, 

it was on the top, suggesting that the source rock may still be exposed 

in a heading. As the uranium occurs with fluorite in a calcite gangue, 

a mineral association not typical of the Abe Lincoln vein system, the 

uranium-bearing areas may be in workings away from the main veins 

or they may be veins that intersect the Abe Lincoln vein system.

The Annie Laurie deposit has been examined by Wright (1951), 

who made a study of the geology and radioactivity, and by Anderson 

and Kurtz (1955), who did a biogeochemical reconnaissance of the 

prospect. Both of the resulting papers state that the deposit dips 

westward, and drilling has therefore been done west of the prospect 

pits. If the deposit dips eastward, however, as we believe that it does, 

the deposit might be explored from the hillside to the east below pits 

A to E, or from the bottom of the gully shown in figure 11.

As in other metallogenic provinces, small amounts of uranium 

minerals are present in many deposits in Arizona exploited for their 

base or precious metals, but most of the deposits described in this 

report probably have too little uranium exposed to merit further 

examination or exploration. With few exceptions, the concentrations 

of uranium appear to be small and do not necessarily indicate that 

there are greater concentrations elsewhere in the deposit or in the 

surrounding area.

REFERENCES CITED

Anderson, R. Y., and Kurtz, E. B., Jr., 1955, Biogeochemical reconnaissance of

the Annie Laurie uranium prospect, Santa Cruz County, Ariz.: Econ.

Geology, v. 50, no. 2, p. 227-232. 

Darton, N. H., and others, 1924, Geologic map of the State of Arizona: Arizona

Bur. Mines and U.S. Geol. Survey, scale 1:500,000. 

Dunning, C. A., 1948, Hack's Canyon uranium mine: Arizona Dept. Mineral

Resources, Phoenix. 

Hewett, D. F., 1925, Carnotite discovered near Aguila, Arizona: Eng. Mining

Jour. Press, v. 120, no. 1, p. 19.
RECONNAISSANCE OF URANIUM DEPOSITS IN ARIZONA A-51

Kaiser, E. P., 1951, Uraniferous quartzite, Red Bluff prospect, Gila County, 

Ariz.: U.S. Geol. Survey Circ. 137,10 p.

.Lasky, S. G., and Webber, B. N., 1949, Manganese resources of the Artillery 

Mountains region, Mohave County, Ariz.: U.S. Geol. Survey Bull. 961, 86 p.

.Lee, W. T., 1908, Geologic reconnaissance of a part of western Arizona: U.S. 

Geol. Survey Bull. 352, 96 p.

Magleby, D. N., and Mead, W. E., 1955, Airborne reconnaissance project, Dripping Spring quartzite, Arizona: U.S. Atomic Energy Comin. RME-2023, 

Tech. Inf. Service, Oak Ridge, Tenn.

-Mead, W. E., and Wells, R. L., 1953, Preliminary reconnaissance of the Dripping 

Spring quartzite formation in Gila and Final Counties, Arizona: U.S. Atomic 

Energy Comm. RMB-4037, Tech. Inf. Service, Oak Ridge, Tenn.

Moore, B. N., and Tolman, C. F., Jr., with contributions by Butler, B. S., and 

Hernon, R. M., 1949, Geology of the Tucson quadrangle, Arizona: U.S. Geol. 

Survey open-file rept, text, and map.

Morrison, R. B., 1940, Ground-water resources of the Big Sandy Valley, Mohave 

County, Ariz.: Arizona State Water Commissioner Rept. (mimeographed).

Neuerburg, G. J., and Granger, H. C., 1960, A geochemical test of diabase as an 

ore source for the uranium deposits of the Dripping Spring district, Arizona: 

Neues Jahrb. Mineralogie, Abb.., V. 94, Festband Ramdohr, p. 759-797.

Palache, Charles, Berman, Harry, and Frondel, Clifford, 1944, Dana's System of 

Mineralogy, 7th eel. v. 1: New York, John Wiley and Sons, Inc.

Rabbitt, J. C., 1953, Properties of uranium minerals, in Geologic investigations 

of radioactive deposits Semiannual progress report, June 1 to November 30, 

1953: U.S. Geol. Survey TEI-390, p. 264-266, issued by U.S. Atomic Energy 

Comm. Tech. Inf. Service, Oak Ridge, Tenn.

-Ransome, F. L., 1922, Ore deposits of the Sierrita Mountains, Pima County,

Ariz.: U.S. Geol. Survey Bull. 725-J, pt. 1, p. 407-440. 

Schrader, F. C., 1909, Mineral deposits of the Cerbat Range, Black Mountains,

and Grand Wash Cliffs, Mohave County, Ariz.: U.S. Geol. Survey Bull. 397,

226 p. 

Wells, R. L., and Ranibosek, A. J., 1954, Uranium occurrences in Wilson Creek

area, Gila County, Ariz.: U.S. Atomic Energy Comm. RME-2005 (rev.),

Tech. Inf. Service, Oak Ridge, Tenn. 

Wilson, E. D., 1941, Tungsten deposits of Arizona: Arizona Bur. Mines Bull.

148, 54 p. 

Wright, R. J., 1950. Reconnaissance of certain uranium deposits in Arizona:

U.S. Atomic Energy Comm., RMO-679, Tech. Inf. Service, Oak Ridge, Tenn. 

Wright, R. J., 1951, Annie Laurie prospect, Santa Cruz County, Ariz.: U.S.

Atomic Energy Comm. RMO-677, Tech. Inf. Service, Oak Ridge, Tenu.

INDEX

Page

Abe'Lincoln mine, description. ______ A-44-46 

Abstract....___________________, 1

Acknowledgments_______________ 2-4 

Anna Bernice claims, description... _____ 23 

Annie Laurie claims, description...... ___ 39-42

Apache group_________________ 12 

Aquarius cliffs_________________ 16,17 

Artillery formation- ____. ___. _ ___ 22 

Atom claims, description. __________ 48 

Autunite_________......._...... 3,14,35,36

Bassetite_______......._........._.. 14

Bibliography__________________ 50-51 

Black Dike deposit, description...__...._ 25-29 

Black Mountain claims, description _____ 15 

Bolsa quartzite_______________.. 34 

Breccia...... 11,13,15,20,22,29,30,33,35,38,40,42,44

Carbonaceous material.. ______ 5,6-7,13,14,24 

Carnotite_____________________ 15,25 

Catherine and Michael claims, description.... 16-18 

Cerussite_____._.--.--.----. 44 

Chinle formation, Anna Bernice claims.___ 23

Hosteen Nez Mining Co. deposits.- .-.. 7

Petrified Forest National Monument .. 24 

Cochise County, description of deposits.. 3-7 

Coconino County, description of deposits.._ 7-12 

Coconino sandstone, Hack's mine.._-.. . 18,20

Orphan claim....... . _..... 8,10

Cofflnite_.______________ 13 

Collapse structure, Hack's mine, _____... 21

Orphan claim..,__________... 8 

Comanche series...__._....._...... 25

Conclusions_______________._... 49-50 

Concretions, uraniferous manganese...._... 7

Contact-metamorphic zone, Black Dike deposit.... .- .-- _- 28-29

Copper Squaw mine, description.____... 29 

Cuba claim________________ ___ 46

Diabase___...__....__.._._.... 12-14 

Dripping Spring quartzite, description of

deposits. ..... . 12-14

Faults.._____......__ . 5,29,40

Fluorine Hill deposit, description..._.___ 3-4 

Fluorite____....._ 3,22,26,28-29,35,36,42,45-46 

Fossil wood, uraniferous.. ______ ___ 7,24

Genie No. 1 claim, description________ 31-34 

Qila County, description of deposits...._... 12-15 

Qlen claims, description___________ 30 

Qolondrina claims, description. _______ 15 

Graham County, description of deposits.. __ 15

Page

Hack's mine, description. ________ A-18-21 

Hematite, radioactive..___._._...... 48

Hermit shale, Hack's mine..________ 18,20,21 

Orphan claim. _____________ 8,9,10,11 

Honey Bee No, 4 claim, description_____ 38 

Hornfels-__________._________ 13-14 

Horses, radioactivity in....__.. . _ _. 5-7

Hosteen Nez Mining Co. deposits, description. 7 

Hyalite, uraniferous_________ . .. 14

Independence claim____________... 46 

Introduction..______._ . .. 1-3

Iris and Natalia claims, description._....... 30-31

Iron-oxide minerals associated with radioactivity. .. 3,22,26,28-29,35,36,42,45-46

Jasper, uranium-bearing .......... 23

Jim Kane mine, description......... 21

Kaibab limestone, Hack's mine........_.... 18

Orphan claim.________....... 8,12

Kasolite......._ __... ............. 31,44

Kitten No. 1 claim, description . 46-47

Lena No. 1 claim, description . 31-34 

Lucky Strike claim, description 16

Maricopa County, description of deposits 15-16 

Martin limestone........... 25

McMillan prospect, description . 48-49 

Mine dumps as source of radioactive material. 16,

45-46,48,50

Moenkopi formation, Petrified Forest National Monument_..______- 25 

Mohave County, description of deposits ... 16-23

Naco limestone._______.. 37 

Navajo County, description of deposits___ 23-25 

Nodules, uraniferous . 7,30

Opal, radioactive.___.___ 14,18 

Oracle granite______.__...._ . 34 

Origin, uranium deposits near diabase.. 14 

Orphan claim, description..... . 7-12

Peeples Valley mine, description . . 47 

Petrified Forest National Monument, descrip- ^j 

tion of deposits. . _-_.__ 24-25 

Petroliferous material, radioactive. 37 

Pima County, description of deposits_____ 25-37 

Final County, description of deposits 38-39 

Pitchblende.____....... _ 20,21,29,31,39,42

Pyromorphite, uraniferous . 15,16,44

Quartzite, radioactive. 36

A-53
A-54 INDEX

Page

Radioactivity measurements.. . _ A-20,38,46,47,49 

Robles Spring deposit, description._____ 4-7

Saleeite.______________________ 14 

Santa Cruz County, description of deposits_ 39-44 

Schoepite ______-----_.________ 45

Shale ..- 10

Shorty claims, description...___.__.__ 38 

Summit mine, description__________ 22-23 

Supai formation, Orphan claim________ 8,10 

Sure Fire No. 1 claim, description. ______ 34-36

Torbernite_..________________ 9,14

Tornado limestone...______________ 25

Toroweap formation ._,_.___.___ 8

Tufa..._.........._....__-___-__ 42

Tuff ____ -_ . .__ 15

Uraninite ............... 11,13,14,23,29,39,42,45

Uranium-bearing minerals. See individual 

mines, claims, and minerals.

Page 

Uranium deposits, general statement.____ A-3

location __________________ 2

See also individual mines and claims, 

UranophaneT__________ 3,14,29,35,44,46,47

Van Hill No. 5 claim, description_______ 36-

Van Hill Nos. 7 and 8 claims, description__ 36-37

Veins-_-. _ 3,5,9,13,16,21,22-23,30.

31,34,35,39,41-42,45,46,4&

White Oak property, description. ______ 42-44 

Wooley No. 1 claim, description_______ 38-39

Yavapai County, description of deposits. _ 44-47 

Yavapai schist, Lucky Strike claim.. . .. 16 

Yuma County, description of deposits____ 48-49

Zippeite .... » . 20

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