GEOLOGICAL SURVEY CIRCULAR 889

nomaiy Near Pringle rringie, 

Black Hills, South Dakota,

"Vii ic«*rl Kw I tnckvrkncc»«4

Southern

Caused by

Rare-Mineral
Lithium Anomaly Near Pringle, 

Southern Black Hills, South Dakota, 

Possibly Caused by Unexposed 

Rare-Mineral Pegmatite

By James J. Norton

GEOLOGICAL SURVEY CIRCULAR 889

1984
Department of the Interior

WILLIAM P. CLARK, Secretary

U.S. Geological Survey

Dallas L. Peck, Director

Free on application to Distribution Branch, Text Products Section, 

U. S. Geological Survey, 604 South Pickett Street, Alexandria, VA 22304
CONTENTS

Page

Abstract ............................................ 1

Introduction .......................................... 1

Pringle anomaly ........................................ 1

The Beecher group of pegmatites .............................. 3

Mining and exploration for lithium minerals, beryl, and tantalite-columbite in

the Black Hills ....................................... 4

Summary ............................................ 7

References cited ........................................ 7

ILLUSTRATIONS

Page

FIGURE 1. Map showing locality of lithium-rich samples and of the Beecher group of pegmatites, southern Black Hills,

S. Dak. ..................................................... 2

2. Graph showing tantalum and niobium contents of specimens of tantalite-columbite from the Etta pegmatite,

Keystone, S. Dak. ............................................... 6

3. Graph showing the relationship between Ta/Ta + Nb and Mn/Mn + Fe in the samples of figure 2 .... 6

TABLES

Page

TABLE 1. Lithium content of biotite schist samples from just east of Pringle, S. Dak. ................ 3

2. Lithium content of biotite schist samples from near the Mateen pegmatite, Hill City, S. Dak. ..... 3

III
LITHIUM ANOMALY NEAR PRINGLE,

SOUTHERN BLACK HILLS, SOUTH DAKOTA,

POSSIBLY CAUSED BY UNEXPOSED RARE-MINERAL PEGMATITE

By James J. Norton

ABSTRACT

Six samples of biotite schist from a site near Pringle, South 

Dakota, contained from 140 to 750 parts per million lithium. 

These values are far greater than are found in mica schists 

in most of the rest of the southern Black Hills. The lithium 

may have emanated from concealed lithium pegmatite, and 

such pegmatite can be of interest as a possible source of rare 

minerals, especially tantalite and beryl. Whether making a full 

test of the anomaly will become economically judicious is much 

less clear.

INTRODUCTION

Analyses for lithium, rubidium, and cesium have 

been used in geochemical exploration for concealed 

lithium pegmatites (Trueman, 1978). The purpose 

was not so much to enlarge lithium reserves, 

which are abundant, as to find rare minerals, such 

as tantalite and beryl. Lithium pegmatites of the 

Black Hills, S. Dak., have been sources of both 

these minerals.

Between 1977 and 1980, the price of tantalite 

rose from about $20 to more than $100 per pound 

of contained Ta^Os. Interest in exploring for tantalite rose accordingly. In 1981 and 1982, a price 

retreat to $20-$25 dampened enthusiasm. Beryl 

in 1977 was about $40 per short ton unit (20 

pounds of contained BeO) and in 1981 and 1982 

it was $100-$130.

PRINGLE ANOMALY

The purpose of this report is to call attention 

to a lithium anomaly found near Pringle, S. Dak., 

during an investigation of the distribution of lithium in mica schists of the southern Black Hills

(Norton, 1981). The principal locality is in biotite 

schist just east of Pringle (fig. 1) at the north end 

of the Shirttail Canyon road, just south of its intersection with U.S. Highway 385.

The six samples of schist from this site had a 

lithium content of 140 to 750 ppm (parts per million). Elsewhere over an area of about 800 km2 

(square kilometers) in the southern Black Hills, 

only 7 of 277 samples of mica schist had as much 

as 140 ppm, and the maximum among these was 

350 ppm. The median of all samples was 52 ppm. 

Three other samples were collected from near 

Pringle, and these also had unusual amounts of 

lithium, at 97, 121, and 157 ppm. For this reason 

their positions are shown on figure 1. These samples are of mica schist of lower biotite content than 

at the Pringle locality.

The Pringle sampling site is near the south edge 

of the Precambrian core of the Black Hills. The 

site is east of a cluster of small pegmatites in a 

biotite-rich schist belonging to a narrow unit that 

trends 18 km due north to Custer (Redden and 

Norton, 1975, fig. 6). The unit has almost no outcrops over this entire distance. North of Custer, 

the biotite schist extends over broad areas and 

ultimately becomes a part of the biotite schist 

facies of the Oreville Formation (Ratte and Wayland, 1969).

Table 1 has data on the six samples of biotite 

schist from the Pringle locality. The schist consists 

mostly of biotite, quartz, and untwinned feldspar, 

but it also has conspicuous metacrysts of garnet 

and muscovite. Heavy-mineral separates obtained 

with bromoform had 620 ppm Li in sample 0-105 

and 1,755 ppm Li in sample 0-106. The light frac-
R.4E. R.5E.

5 KILOMETERS

I

EXPLANATION

 Sampling site of table 1

X Other sampling sites, showing lithium 

121 content in parts per million

FIGURE 1. Map showing localities of lithium-rich samples and of the Beecher group of pegmatites, southern Black Hills, S. Dak.

tions had 76 and 150 ppm, respectively. The lithium thus seems to be concentrated in biotite.

Most of the samples were taken from near a 

northerly striking feldspar-quartz pegmatite about 

2 m (meters) thick and 50 m long. Sample 0-109 

is nearer another pegmatite, which is about 1 m 

east of the first one and is about 0.3 m thick and 

6 m long. In all samples except 0-105, the lithium 

content seems strikingly related to proximity to 

these pegmatites. The pegmatites, however, are 

of quite ordinary appearance, and the one sample 

analyzed had only 19 ppm lithium. West of the 

two pegmatites at the sampling site are many 

other thin tabular pegmatites of northerly strike. 

They seem to be separate intrusions but could be 

offshoots from the top or bottom of a much larger 

pegmatite.

Although the Pringle analyses are clearly 

anomalous, a test of how they compare with schist 

enriched in Li by a known lithium pegmatite was 

made at the Mateen spodumene mine, 35 km north 

of Pringle at Hill City. The Mateen was chosen 

because the host rock is the same kind of biotite 

schist as at Pringle. The pegmatite has a steep 

eastward dip at the sampled locality, and according to Erickson and Steven (1953, pis. 26 and 27) 

the top of the intrusion was only about 15 m above 

the surface. Table 2 shows that the lithium contents are not much different, although perhaps a 

little lower, than at Pringle. Hence the Pringle 

anomaly seems likely to have been caused by lithium pegmatite not now exposed.

A harder question to answer is whether the suspected lithium pegmatite near Pringle is below the 

surface or has been eroded away from above the 

surface. A. A. Beus and his colleagues have 

examined this kind of problem, and translations 

of some of the pertinent material have been provided by D. L. Trueman and Petr Cerny. Apparently the high lithium contents at Pringle are a 

favorable indication that a pegmatitic source lies 

beneath the locality. The Mateen analyses are in 

accord with this implication, for the samples came 

from near the top of the pegmatite. Semiquantitative analyses of Pringle samples 0-105 and 0-106 

cast a little more light on the subject. These 

analyses indicate 50 and 10 ppm Be and 20 and 

50 ppm Sn, respectively. Similar analyses of 98 

biotite schist samples from elsewhere in the Black 

Hills show that one sample has 5 ppm Be and all 

others have less. In these same samples, Sn 

reached a maximum of 20 ppm, and that too was
Sample Number 

Field Laboratory

Lithium,

content 1

(ppm) Location

0-105 D-187195 186 West of Shirttail Canyon road; 0.3 m east

of 2-m-thick pegmatite.

0-106 D-187196 750 Do.

0-107 D-l90406 520 Do.

0-108 D-190407 270 Middle of road; 3 m east of pegmatite.

0-109 D-190408 190 In road; north of sample 0-108 and 6 m east

of 0.3-m-thick pegmatite.

0-110 D-190409 140 60 m south of other samples; no pegmatite

exposed nearby.

1 Analyses by atomic absorption. Analysts: Carol Gent and Violet 

Merritt.

in only one sample. The Be and Sn contents tend 

to support the view that the source is at depth. 

No other data at hand are suitable for further appraisal of the problem. Because the tests are far 

less than rigorous, one can conclude only that the 

cause of the anomaly is somewhat more likely to 

be below than above the present surface. Geologic 

mapping and structural analysis of the cluster of 

pegmatites west of the sampling site might show 

whether some or all these pegmatites are likely 

to be at the top or bottom of a large pegmatite 

that could have caused the anomaly.

THE BEECHER GROUP OF PEGMATITES

The best means of judging the possible nature 

of lithium pegmatites that might be found near 

Pringle is to examine the geology of some known 

lithium pegmatites of the southern Black Hills. 

Most of these are far to the north near the edge 

of the pegmatite region. The only significant exception is the three lithium pegmatites of the 

Beecher group, which are 11 km north of Pringle 

and are in much the same geologic environment 

as at Pringle (Redden and Norton, 1975, fig. 6; 

Norton, 1975, fig. 21). These pegmatites are so 

large and exceptional among Black Hills pegmatites that it would be rash to assume that Pringle 

has equal deposits. Nevertheless, the Beecher 

lithium pegmatites are much nearer Pringle than 

any others and have the most relevance in predicting the outlook for exploration.

Two of the pegmatites, the Beecher Lode and 

Beecher No. 2, have been described by Joralemon 

(1953a, b). The third pegmatite, called Beecher 

No. 3-Black Diamond, has been described in detail 

by Redden (1959, 1963).

The Beecher Lode is 265 m long and as much 

as 25 m thick. Information is meager about how 

deep it goes and about its structure at depth. The 

exposed part of the pegmatite consists mainly of 

feldspathic outer zones and a quartz-spodumene

TABLE 2. Lithium content ofbiotite schist samples from near the Mateen pegmatite,

Hill City, S. Dak. 1

Sample Number

Field Laboratory

MAT-3 D-223184

MAT-4 D-223185

MAT-5 D-223186

MAT-1 D-223182

MAT-2 D-223183

Lithium

content 1

(ppm)

138

242

325

158

420

Distance from contacts of

At east contact.

1.2 m from east contact.

23 m from east contact.

At west contact.

1.2 m from west contact.

pegmatite

'Collected from between sections _B^' and _CC_' of Erickson and Steven 

(1953, p. 126). Analyses by atomic absorption. Analyst: G. Angsten.
inner zone. The Beecher Lode became prominent 

as a source of amblygonite early in the century 

when amblygonite was the favored source of lithium. Its production of about 1,800 metric tons is 

more than one-fifth of the total Black Hills output 

of amblygonite. Beryl production exceeds 100 

tons, but the beryl is iron stained and anhedral, 

and hence difficult to cob to an acceptable degree 

of purity. George Bland (oral commun., Aug. 31, 

1981) estimated the tantalite-columbite production 

to be at least 55 metric tons, which would be probably at least one-half of the total Black Hills production. The minable concentrations of amblygonite, tantalite-columbite, and much of the beryl 

were found in the outer part of the quartzspodumene zone.

The Beecher No. 2 pegmatite is exposed for a 

length of 350 m and has an average thickness of 

60 m. The vertical dimension is unknown. The 

body is a multiple intrusion consisting of three 

coalescing pegmatites, each of which has a core 

of albite-quartz-spodumene pegmatite and outer 

zones of quartz-albite-muscovite and albite-quartz 

pegmatite. The pegmatite was mined for 

spodumene by the Lithium Corporation of 

America during the 1950's. Although the pegmatite has been rather extensively opened up, no 

rare minerals of commercial value have ever been 

reported.

At the Beecher No. 3-Black Diamond deposit, 

the original top of the pegmatite was probably 

nowhere more than about 10 m above the present 

surface. Outcrops are rather sparse and mine 

workings are small. Hence, exploring this deposit 

is much like exploring a concealed pegmatite. It 

was tested in a diamond-drilling program by the 

Lithium Corporation of America, and the results 

were described by Redden (1963).

The pegmatite is 540 m long at the surface and 

probably longer in the subsurface. The thickness 

is highly variable, but the average is about 25 m. 

Drilling has shown that the pegmatite extends to 

a depth of at least 60 m. Calculations from Redden's cross sections show that it is likely to contain 

as much as 3,000,000 metric tons of rock, which 

is extremely large for a Black Hills zoned pegmatite. Redden (1959, 1963) separated the pegmatite 

into five zones containing differing quantities of 

feldspars, quartz, and muscovite, and a sixth zone, 

apparently small, of quartz-perthite-albitespodumene pegmatite. The only production has 

been 342 tons of beryl, which was in a small and

structurally unusual part of an outer zone. Tantalite-columbite has not been found, but the pegmatite has not been explored enough to show that 

it does not contain tantalum ore.

These three pegmatites are large. Two of them 

have been important mines for lithium minerals, 

and the third contains lithium minerals. A lithium 

anomaly almost certainly exists in the nearby 

schists, although no tests to prove this have been 

attempted. One of the pegmatites has produced 

only spodumene, and has little or no promise for 

other minerals. Two pegmatites have been significant sources of beryl. One of these also has had 

a sizable output of tantalite-columbite, and the 

other may contain undiscovered deposits. The concentrations of beryl and tantalite-columbite, however, constitute only small parts of this group of 

pegmatites.

MINING AND EXPLORATION FOR

LITHIUM MINERALS, BERYL, AND

TANTALITE-COLUMBITE IN THE

BLACK HILLS

None of the known rare-mineral pegmatites in 

the Black Hills was found by geochemical exploration, nor has there been much effort to find them 

by this means. The reason for the slightness of 

the effort may be that the nature of Black Hills 

pegmatites makes exploration for concealed deposits economically unattractive. Finding a few 

samples of lithium-rich schist is only a minor preliminary step in finding, developing, and mining 

a pegmatite. The lithium-rich schist near Pringle 

is so remote from the known lithium pegmatite 

localities of the Black Hills that it normally would 

not be sampled in geochemical prospecting for 

rare-mineral pegmatites. Perspective for gauging 

the advisability of investigating the Pringle anomaly can be obtained by examining a few aspects 

of the mining and geology of Black Hills pegmatites.

Most of the lithium production has been from 

mining operations in which lithium minerals were 

the main product. Beryl and tantalite-columbite 

have had a status better described as that of a 

byproduct or coproduct. Concentrations of these 

minerals have, of course, been found in natural 

outcrops and then mined out. Several such discoveries were an accidental result of prospecting 

for other minerals. Most concentrations, however, 

especially of beryl, have been exposed during mining for other products. They were mined when
found, or in some instances left untouched until 

a price increase caused them to be mined.

Although Black Hills pegmatites were the dominant source of the world's lithium in the first half 

of the century, subsequent expansion of the lithium market caused the industry to turn away from 

the small deposits of the Black Hills and to obtain 

its supplies from much larger deposits elsewhere 

in the world. Lithium mining in the Black Hills 

virtually halted in 1960. There is no imminent likelihood that lithium mining in the region will return 

to its previous level.

Total beryl production of the Black Hills probably now slightly exceeds 5,000 metric tons. 

Perhaps somewhat more than half of this came 

from a dozen pegmatite mines. Many of these 

were feldspar quarries in which most of the beryl 

would have been unobtainable if the feldspar-rich 

parts of the pegmatite had not been removed. At 

the Peerless pegmatite, which has the largest production, the beryl was a byproduct of mining for 

scrap mica from a narrow outer zone. A similar 

zone contained the beryl mined at the Beecher No. 

3. The beryl-rich rock was discovered in an old 

prospect pit, and beryl was the only mineral 

mined; mining was discontinued partly for lack of 

coproducts to help finance further operation. At 

the Bob Ingersoll Mine, where two pegmatites 

have yielded about as much beryl as the Peerless, 

the main incentive for mining was lithium minerals. In the light of these experiences with the mining of beryl from outcropping pegmatites, little 

weight should be placed on the potential for finding minable beryl deposits in an unexposed pegmatite.

With tantalite-columbite, experience is smaller 

and what experience there is has lost much of its 

relevance as a result of price changes. Until the 

late 1970's, prices were too low and the availability 

of buyers for tantalite-columbite was too erratic 

to encourage prospecting and mining in the Black 

Hills. Recorded production was 85 metric tons 

through 1973 (Norton, 1975), and unrecorded production plus recent output may have brought the 

total to more than 100 metric tons. Most of this 

production came from two deposits. According to 

George Bland (oral commun., Aug. 31, 1981), the 

Beecher Lode has supplied at least 55 metric tons, 

a substantial share of which appears not to have 

been included in published statistics. Personal records of A. I. Johnson (oral commun., Sept. 17, 

1981) show the production at Tinton in the northern Black Hills to be 30 metric tons from the 

Giant-Volney pegmatite and adjacent placer 

ground. Less than 10 other pegmatites in the 

Black Hills could have produced more than 1 metric ton each. The overall contribution of all other 

pegmatites is at best a few metric tons. The Black 

Hills has about 40 sizable pegmatite mines and 

many smaller mines and prospects. Finding only 

two significant tantalite deposits hardly encourages hope that additional discoveries can be made 

easily. At the Beecher Lode most of the tantalite 

was made accessible by mining for other minerals. 

The tantalite at Tinton was mined as the main 

product, although it probably was originally discovered as a result of prospecting for tin.

Some Black Hills zoned pegmatites are large by 

most standards, but none of those so far found 

are more than a tiny fraction of the size of the 

Tanco pegmatite, Bernic Lake, Manitoba, where 

the success at mining tantalum minerals has 

stimulated interest in exploration elsewhere. The 

Hugo is the largest highly differentiated pegmatite in the Black Hills for which nearly complete 

data about its size are available. It originally had 

about 1,570,000 metric tons of rock (Norton and 

others, 1962, table 19). Tanco, according to calculations from an isopach map by Grouse and others 

(1979, fig. 3), has somewhat more than 50,000,000 

tons. Reserves of tantalum ore when mining began 

in 1969 were 1,700,000 metric tons containing 0.23 

percent Ta^Og (Howe, 1968, p. 44). At the end 

of 1979, higher prices had dropped the minable 

grade to 0.137 percent (Jones, 1980, p. 267), and 

the size of the bodies of ore, mined and not yet 

mined, became perhaps 3,000,000 metric tons, or 

only about 6 percent of the entire pegmatite. Ore 

bodies occupying a similar share of a typical Black 

Hills pegmatite would be extremely small and difficult to find. Tantalite-columbite does, however, 

tend to be most abundant in the inner units of 

zoned pegmatites, and exploration can be focused 

on those units. Tantalite-bearing units can be 

zones or parts of zones, but they also can be replacement bodies, as at Tinton (Page and others, 

1953, p. 204-205) and at the Tanco deposit (Grouse 

and others, 1979). Many replacement bodies are 

irregular and much more erratic than zones, and 

hence are more difficult to explore. At Tanco the 

tantalum ore was discovered not by exploration 

for tantalum, but as an unforeseen result of years 

of exploring for lithium minerals. The recognition 

of the existence of tantalum ore bodies came from
reexamining core from 75 drill holes (Howe, 1968, 

p. 39).

In the Black Hills the first result of the increase 

in the price of tantalite was to draw attention to 

old mine dumps. Black Hills pegmatite mines, in 

the course of producing somewhat more than 

2,000,000 metric tons of various commercial minerals, have accumulated at least 3,000,000 metric 

tons of waste rock now in numerous dumps. Some 

of the dumps have enough tantalite to have become economically attractive at the high prices of 

1981, but their merits may not be apparent except 

from tests of bulk samples (R. L. Cullum, oral 

commun., Aug. 31, 1981). Renewed mining of pegmatites known to contain tantalite was modest. 

Searching for concealed pegmatites took a distant 

third place. If high prices return, some deposits 

other than the Beecher Lode and Giant-Volney 

may be found to have enough tantalite to become 

economically important, even if too low grade to 

have been of interest or perhaps even to have 

been noticed previously.

One of the remarkable advantages of the Tanco 

deposit is the high ratio of Ta to Nb in its several 

tantalum minerals (Grice and others, 1972). In the 

Black Hills the content of Ta is generally much 

lower and Nb correspondingly higher. Furthermore, tantalite-columbite in a single pegmatite 

may range from tantalum-rich to niobium-rich. In 

10 specimens from the Etta Mine, Keystone, S. 

Dak., Headden (1891, p. 95) found a continuity 

of compositions from 18.20 percent Ta^C^ and 

64.09 percent1 Nb205 at one extreme to 53.28 percent TaA and 29.78 percent Nb205 at the other. 

Figure 2 shows the wide distribution of Ta and 

Nb in these specimens, but does so in atomic percent to show how well these old analyses conform 

to the tantalite-columbite formula, (Fe,Mn) 

O(Ta,Nb)205. Page and others (1953, p. 58) 

suggested that such differences are attributable 

to an increase in the Ta-Nb ratio toward the centers of pegmatites, and Grice and others (1972, 

p. 640) found such a trend in the Tanco pegmatite. 

The range in the Ta-Nb ratio was not commercially troublesome in the Black Hills during the 

last few years; nearly all shipments and all concentrates from test mill runs had far more than the 

acceptable minimum of 30 percent Ta^C^ (R. L. 

Cullum and George Bland, oral communs., Aug. 

31, 1981). Experience in new deposits would not 

necessarily be the same.

LU

o

DC 

LU 

0.

O

10 -

5 

10 15 20 

ATOMIC PERCENT Nb

25

FIGURE 2. Tantalum (Ta) and niobium (Nb) contents of 10 

specimens of tantalite-columbite from the Etta pegmatite, 

Keystone, S. Dak. Calculated from analyses by Headden 

(1891, p. 95). The line for Ta + Nb=22.2 percent shows the 

contents in the formula for tantalite-columbite.

George Bland has commented (oral commun., 

Aug. 31, 1981) that columbite seems generally to 

have more iron-oxide alteration than tantalite and 

probably has a higher Fe-Mn ratio. This observation led to plotting the Etta analyses on figure 

3, which shows high Ta to be accompanied by high 

Mn and high Nb to go with high Fe. Cerny and

0.6

0.5

o

Sz

JO

2

+ 

a

%

0.3

0.2

0.1

0.1 0.2 0.3 0.4 0.5 

Mn/Mn + Fe IN ATOMS

0.6 0.7

'Published as 54.09, but internal evidence proves this to be a misprint.

FIGURE 3. Graph showing the relationship between Ta/ 

Ta + Nb and Mn/Mn + Fe in the samples of figure 2.
others (1981, fig. 104) show a similar trend in Manitoba. The relationship seems to have no commercial importance and no obvious geologic explanation. The subject is brought up here only because 

it may interest others.

SUMMARY

Mica schist samples from near Pringle, South 

Dakota, are anomalously rich in lithium. This 

anomaly suggests the possibility that one or more 

lithium pegmatites lies beneath the surface. Interest in finding another lithium pegmatite in the 

Black Hills has long been negligible, but interest 

in finding tantalum minerals and beryl, which are 

associated with lithium deposits, has been much 

greater. Hidden lithium pegmatites have few attractions as potential sources of tantalum or beryl 

that are not also possessed by outcropping lithium 

pegmatites.

The primary purpose of this report is to announce the existence of the Pringle lithium 

analyses. The nearest known lithium pegmatites 

are 11 km away in the Beecher group, which has 

three large deposits. These deposits suggest the 

nature of what could be found at Pringle. They 

and other Black Hills pegmatites also illuminate 

the difficulties of finding a rare mineral concentration even after a lithium pegmatite has been 

discovered.

REFERENCES CITED

Centf, Petr, Trueman, D. L., Ziehlke, D. V., Goad, B. E., 

and Paul, B. J., 1981, The Cat Lake-Winnipeg River and 

the Wekusko Lake pegmatite fields, Manitoba: Manitoba 

Department of Energy and Mines, Mineral Resources Division, Economic Geology Report ER80-1, 216 p.

Grouse, R. A., Cerny, Petr, Trueman, D. L., and Burt, R. 

0., 1979, The Tanco pegmatite, southeastern Manitoba: 

Canadian Mining and Metallurgical Bulletin, v. 72, p. 142- 

151.

Erickson, M. P., and Steven, T. A., 1953, Mateen spodumene 

prospect, in Page, L. R., and others, 1953, Pegmatite investigations, 1942-1945, Black Hills, South Dakota: U.S. 

Geological Survey Professional Paper 247, p. 150-156.

Grice, J. D., Centf, Petr, and Ferguson, R. B., 1972, The 

Tanco pegmatite at Bernic Lake, Manitoba; II. Wodginite, 

tantalite, pseudo-ixiolite, and related minerals: Canadian 

Mineralogist, v. 11, p. 609-642.

Headden, W. P., 1891, Columbite and tantalite from the Black 

Hills of South Dakota: American Journal of Science, v. 

141, p. 89-102.

Howe, A.C.A., 1968, Canada's first tantalum producer: Western Miner, v. 41, no. 12, p. 39-49.

Jones, T. S., 1980, Columbium and tantalum, in U.S. Bureau 

of Mines Minerals Yearbook 1978-79, v. 1, Metals and minerals: p. 259-270.

Joralemon, Peter, 1953a, Beecher Lode, in Page, L. R., and 

others, 1953, Pegmatite investigations, 1942-1945, Black 

Hills, South Dakota: U.S. Geological Survey Professional 

Paper 247, p. 65-71.

 1953b, Beecher No. 2 and Longview spodumene claims, 

in Page, L. R., and others, 1953, Pegmatite investigations, 1942-1945, Black Hills, South Dakota: U.S. Geological Survey Professional Paper 247, p. 71-73.

Norton, J. J., 1975, Pegmatite minerals, in Mineral and water 

resources of South Dakota (2d ed.): South Dakota Geological Survey Bulletin 16, p. 132-149.

 1981, Origin of lithium-rich pegmatitic magmas, southern Black Hills, South Dakota [abs.]: Geological Society 

of America Abstracts with Programs 1981, v. 13, no. 4, 

p. 221.

Norton, J. J., Page, L. R., and Brobst, D. A., 1962, Geology 

of the Hugo pegmatite, Keystone, South Dakota: U.S. 

Geological Survey Professional Paper 297-B, p. 49-127.

Page, L. R., and others, 1953, Pegmatite investigations, 1942- 

1945, Black Hills, South Dakota: U.S. Geological Survey 

Professional Paper 247, 228 p.

Ratte, J. C., and Wayland, R. G., 1969, Geology of the Hill 

City quadrangle, Pennington County, South Dakota A 

preliminary report: U.S. Geological Survey Bulletin 1271- 

B, p. B1-B14.

Redden, J. A., 1959, Beryl deposits of the Beecher No. 3-Black 

Diamond pegmatite, Custer County, South Dakota: U.S. 

Geological Survey Bulletin 1072-1, p. 537-559.

 1963, Diamond-drilling exploration of the Beecher No. 

3-Black Diamond pegmatite, Custer County, South 

Dakota: U.S. Geological Survey Bulletin 1162-E, p. ElEll.

Redden, J. A., and Norton, J. J., 1975, Precambrian geology 

of the Black Hills, in Mineral and water resources of South 

Dakota (2d ed.): South Dakota Geological Survey Bulletin 

16, p. 21-28.

Trueman, D. L., 1978, Exploration methods in the Tanco mine 

area of southeastern Manitoba, Canada: Energy, v. 3, p. 

293-297.

^ U.S. GOVERNMENT PRINTING OFFICEi 1984 0-461-431/10076