Distribution of Gold, Tellurium 

Distribution of Gold, Tellurium 

Silver, and Mercury in Part 

of the Cripple Creek 

District, Colorado 

By Garland B. Gott, J. Howard McCarthy, Jr. 

Gordon H. VanSickle, and John B. McHugh 

GEOLOGICAL SURVEY CIRCULAR 543 

Washington J 967 
United States Department of the Interior 

STEWART L. UDALL, Secretary 

Geological Survey 

Wiltiam T. Pecora, Director 

First printing 1967 

Second printing 1967 

Third printing 1969 

Free on application to the U.S. Geological Survey, Washington, D.C. 20242 
Abstract-----------------------------------

Introduction--------------------------------

Geologic environment-----------------------

Material sampled---------------------------

Analytical procedures-----------------------

CONTENtS 

Page 

1 

1 

2 

2 

2 

Anomalous area --------------------------- ~ 

Distribution of gold, silver, tellurium, and 

mercury---------------------------------

Economic potential -------------------------

References --------------------------------

IUUSTRATIONS 

Page 

2 

2 

3 

3 

Page 

Figure 1. Index map of Colorado showing area of this report--------------------------------------~ 1 

2. Map showing sampled localities and area of figures 3-7 ----------------------------------· 4 

3-7. Detailed maps showing .concentration of gold, silver, tellurium, and mercury 

at each locality sampled: 

3. Gold, average concentration ------------------------------------------------------ 5 

4. Gold, highest concentration------------------------------------------------------- 6 

5. Silver, highest concentration------------------------------------------------------ 7 

6. Tellurium, highest concentration-------------------------------------------------- 8 

7. Mercury, highest concentration --------------------------------------------------- 9 

Table 1. Abundance of gold, silver, tellurium, and mercury in the earth's crust, in volcanic rocks of 

the entire Cripple Creek district, and in rocks of the area of the gold anomaly discussed 

Page 

in this report----------------------------------------------------------------------- 3 

III 

Distribution of Gold, Tellurium, Silver, and Mercury in part of thq 

Cripple Creek district, Colorado 

By Garland B. Gott, J. Howard McCarthy, Jr., Gordon H. VanSickle, and John B. McHugh 

ABSTRACT 

Geochemical exploration studies were undertaken in the Cripple 

Creek district to test the possibility that large low-grade gold 

deposits might be found. Surface rock samples taken throughout 

the district indicate that the volcanic rocks between the productive veins contain an average of about 0.6 ppm (part per million) 

gold, ln an area about 3,800 feet long and 500 feet '!ide near the 

Cresson mine in the south-central part of the district, scattered 

surface samples show that the rocks contain an average of 2.5 

ppm gold, equivalent to $2.50 per ton. Inasmuch as veins that 

contain more than 2.5 ppm may also exist ln the area, systematic 

sampling by trenching and drilling is warranted. 

The famous Cripple Creek mining district, 20 miles 

southwest of Colorado Springs, Colo. (fig. 1), has produced about 21 million ounces of gold since its discovery in 1891. Value of this gold exceeds the total 

output from all other mining districts in the Front 

Range combined (Lovering and Goddard, 1950, p. 7). 

In the past decade, however, the last major mill and 

the last of the active mines were closed, threatening 

an end to the productive life of the district. As the 

mining potential of blocks of ground-as contrasted to 

that of veins alone-has not been extensively investigated, the Geological Survey recently begangeochemical testing over the district as a whole, and the U.S. 

Bureau of Mines has made an engineering and economic 

study of the potential for large-scale surface mining 

operations in the district. This report pertains to the 

strongest and most extensive gold anomaly found during 

the geochemical investigation. A geochemical report on 

the entire district, giving all the analytical data, will 

be published later. 

the gold in unoxidized ore occurs as tellurideL The 

recent development of sensitive analytical methods and 

techniques for the determination of tellurium (Lakin 

and Thompson, 1963}, mercury(VaughnandMcCarthy, 

1964}, silver (Nakagawa and Lakin, 1965}, anci gold 

(Lakin and Nakagawa, 1965) makes it possibletostudy 

the geochemical distribution and abundance of these 

elements. The gold deposits have been descrit~ by 

Cross and Penrose (1895}, Lindgren and Ransome 

(1906), Loughlin (1927), Loughlin and Koschmann 

(1935), Kosch mann (1949}, and Lovering and Goddard (1950). 

Acknowledgments.-lt is a pleasure to acknowledge 

the warm cooperation of Max Bowen, Presidenr.. and 

Charles Carlton, Manager of Mines, of the Golden Cycle Corp. The authors appreciate the assistance d•lring 

the field investigations by Prof. Gunther Frie~rich, 

Professor of Geochemistry, U n i v e r sit y of Aa~hen, 

West Germany. 

108" ----2r--:_...!.o.!:---

---- - I C) 

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<[ 

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a:: 

lL 

·~ _;-, TELL~R! ~ ~LOitADO ....... . 

COUNTY ~.!3f:~:ICL1t 

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The investigations included a study of the distri- 3a·l----+-------+--------l....::::::.."'=""-f::=::===~ 

bution in surface rocks of gold, silver, tellurium, and 

mercury-elements commonly associated in gold deposits. The high mobility of mercury and tellurium 

apparently permits them to form a primary leakage 

halo above deposits of less mobile metals such as 

gold, and their geochemical distribution may therefore 

furnish clues to the distribution of gold and silver. At 

Cripple Creek, tellurium in particular was considered 

to be a potentially useful indicator because most of 

1 

--~~--- ______ __. 

50 0 50 100 MILES 

Figure 1.-Index map of Colorado showing areaofthis 

report, 
GEOLOGIC ENVIRONMENT 

The gold deposits of the Cripple Creek district are 

largely confined to a roughly elliptical volcanic subsidence basin abo4t 4 miles long and 2 miles wide that 

is surrounded by Precambrian granite, gneiss, and 

schist (fig. 2). The basin is filled with fractured and 

brecciated fragmental rocks, chiefly latite-phonolite 

and phonolite, of Tertiary (Miocene) age. Rocks ofthe 

basin are mainly volcanic near the surface but include 

increasing amounts of nonvolcanic material at depth. 

The v,olcanic rocks_ are intruded by dikes and irregular 

masses of phonolite, latite-phonolite, trachyte, syenite, trachydolerite, vogesite, and monchiquite. Brecciation and fracturing were caused mostly by subsidence of the consolidated fragmental rocks in the basin 

and recurrent explosive eruptions. The major fracture 

system trends generally north, and it is in these fractures that gold telluride ores were localized. 

Investigations by Loughlin and-Koschmann (1935) 

indicate that the mineralizing solutions entered the 

volcanic co~plex through sevez:al channel ways and 

migrated upward and laterally through the main fissure 

zones. As these solutions ascended they spread outward into shallower subsidiary fracture zones. Most 

of the ore deposits are in the relatively shallow subsidiary fracture zones, but some of those within the 

main fissure zones continue to the deepest workings, 

3,000 feet or more below the surface. 

MA11RJAL SAMPLED 

Samples of bedrock are difficult to obtain in the district because outcrops are scarce and much ground is 

covered by mine dumps. Most samples were collected, 

therefore, from shallow pits that had been dug to bedrock by the early prospectors; sample locations are 

shown infigure2. Manyofthesepitshave been partially refilled by surficial debris during the years since 

they were dug, and at these the bedrock material on the 

dumps was sampled. The lack of bedrock exposures 

made it impossible to sample systematically, and consequently the set of samples may not be representative 

of all the bedrock. The analytical data presented here 

probably are lower than would be obtained if bedrock 

could have been sampled directly; the pits sampled 

were shallow presumably because they lacked any 

mineralized structures, such as small veins or joint 

surfaces, to lure the prospector onward. 

ANALYTICAL PROCEDUI!S 

Gold was determined by a wet chemical method using 

atomic absorption spectrophotometry. The results obtained by this method are very close to those given by 

fire assay, as shown in the following table in which 

analyses of 10 samples by both methods are compared. 

Analyses (prm) 

SBIIIple Atomic: absorption 

CC- (by Gordon H. VanSic:kle) 

5oo---- 2.2 

503---- .1 

506A-- 3,3 

508--- 14.3 

512---- 6,2 

514B--- 7.5 

514D-- 4,6 

Sl6-- S,7 

519A--- 7,4 

5208----- 3.4 

Fire auay (by'(), H, Parker, 

J, D. Mensik, and Claude 

Huffman, Jr.) 

2.0 

,07 

2.5 

14,1 

5,4 

7.1 

4,3 

s.o 

6,1 

2,8 

Tellurium was determined by a se~sitivewetchemical method developed by Lakin and Thompson (1963). 

Silver was determined by a wet cl'~mical catalytic 

method using atomic absorption; and mercury was determined instrumentally by an atomic absorption technique (Vaughn and McCarthy, 1964 ). 

ANOMALOUS AREA 

An extensive gold anomaly isshow.,bythegeochemical sampling in the vicinity of the Cresson mine in 

the SE!ai: sec. 19, SW!ai: sec. 20, and NE¥ sec. 29. The 

area extends about 2,000 feet northw~stwardand2,000 

feet southeastward from the Cresson mine. W it hi n 

this area 2 to 5 samples were collected at each locality 

sampled. The average concentration of gold in samples 

at each locality is shown on figure 3, and the highest 

concentration of gold, silver, tellurium, and mercury 

in samples at each locality is show"'\ on figures 4, 5, 

6, and 7, respectively. The area witr'nwhichall samples contain at least l ppm (part pe':" million) gold is 

about 3,800 feet long and 500 feet wicte. Average value 

(arithmetic) of 49 samples from witt~.n this area is 2.5 

ppm gold (approx $2.50 per ton); irdividual samples 

range from 1 to 14.5 ppm. 

DfSTRIIUTION Of GOLD~ SILVER, TELLURIUM, AND MERCUIY 

Distribution patterns of gold, silv<?.r, and tellurium 

(figs. 3-6) are nearly identical in th~ anomalous area; 

the distribution of mercury (fig. 7) is similar but more 

restricted. The distribution pattern<;~ of gold, silver, 

and tellurium probably reflect the distribution of gold 

and silver tellurides. Table 1 shows the average concentration and the enrichment above ~rustal abundance 

of the four metals. Although mercury-in the form of 

cinnabar-occurs locally in the distri~t. it is not greatly 

enriched above crustal abundance h the area of this 

report. Tellurium and gold are gre:11tly enriched and 

silver is moderately so. The mercury in the goldbearing veins probably was emplaced during the waning 

and cooling stages of mineralizatio'1, Such an interpretation is strongly supported by the occurrence of 

late-stage cinnabar in the Cresson mine, where it 

locally coats the gold tellurides. 

2 
Table 1.-Abundance of gold. silver, tellurium. and 

mercury in the earth's crust, in volcanic rocks of 

the entire Cripple Creek district, and in rocks of 

the area of the gold anomaly discussed in this report 

Gold 

Earth's crust---pp- .!/o,oo2s 

Cripple Creek district: 

Average concentration 

(282 saaples) in 

volcanic rocks 

!~:~~:~~~~-~--do- ,6 

Average concentration 

(49 samples) within 

the gold anomaly--do- 2,5 

Enrichment within the 

gold anomaly in excess of that in the 

earth 'a crust 

(factor)----------- 1,000 

.!/From DeGrazia and Haskin (1964), 

1/From Goldschmidt (1958), 

Silver Telluriua Mercury 

l/o.o2 Yo.oo2 llo.o6 

.92 2,7 .19 

3,1 10,7 • 75 

155 5,350 12.5 

~From Green (1959), 

i/ Analysts: Gold, Gordon II, VanSickle; sUver, H, H, l>akagawa and 

J, B, McHugh; tellurium, J, B. :tcHugh; mercury, Henriette llcCarthy and ll, W, 

JS!lea• 

ECONOMIC POTENTIAL 

The Cripple Creek district has produced gold valued 

at nearly one-half billion dollars at the time of sale, 

and worth nearly three-quarters of a billion dollars at 

the present price. It seems unlikely that all the gold 

within the district has been extracted, but exploration 

and mining of veins similar to those that have been 

mined in the past probably would be prohibitively expensive. Because of this and because more gold has 

been mined from s h a 11 ow deposits than from deep 

ones, the best possibility for the discovery and development of additional gold reserves within the district appears to be large low-grade deposits that can 

be mined by low-cost methods from the surface. 

The anomalous area described in this report conceivably could constitute just such a deposit, particularly since the concentrations reported herein are 

thought to approach minable grade. The com p u t e d 

amount of rock within the anomalous area is about 15 

million tons per 100 feet of depth; and if the aver age 

grade is 2.5 ppm gold as the samples at the surface 

suggest, a mass of rock of this size would contain 

about $37.5 million worth of gold. Inasmuch as the 

deepest mining within the district has reached 3,000 

feet, the body of rock of this grade could reasonably 

be expected to extend to depths of at least s ever a 1 

hundred feet. 

Whether or not the results of preliminary sampling 

reported here are representative of the gold content 

of a large body of rock, they identify an area sufficiently anomalous in gold to warrant systematic sampling, including such trenching or drilling as might be 

necessary to allow the sampling. Trenching would be 

required to obtain either grid or channel samples ·of 

the bedrock in much of the area, and angle dr~u holes 

would be required to reach the bedrock beneath large 

dumps. The U.S. Bureau of Mines is currently planning 

such sampling in its program of research on s·ampling 

of low -grade deposits. 

Cross, Whitman, and Penrose, R. A. F., Jr., 1895, 

Geology and mining industries of the Cripple Creek 

district, Colorado: U.S. Geol. Survey 16th Ann. 

Rept., pt. 2, p. 1-209. 

DeGrazia, A. R., and Haskin, Larry, 1964, On the gold 

contents of rocks: Geochim. et Cosmochim. Acta, 

v. 28, no. 5, p. 559-564 • 

Goldschmidt, V. M., 1958, Geochemistry [ed. by Alex 

Muir]: London, Oxford Univ. Press, 730 p. 

Green, Jack,. 1959, Geochemical table of the dements 

for 1959: Geol. Soc. America Bull., v. 70, p. 1127-

1184. 

Koschmann, A. H., 1949, Structural control ofthegold 

deposits of the Cripple Creek district, T e 11 e r 

County, Colorado: U.S. Geol. Survey Bull. 955-B, 

p. 19-58. 

Lakin, H. W., and Nakagawa, H. M., 1965, A spectrophotometric method for the determination of 

traces of gold in geologic materials,.!.!!.. Ge:0logical 

Survey research 1965: U.S. Geol. SurvP.y Prof. 

Paper 525-C, p. Cl68-Cl71. 

Lakin, H. W., and Thompson, C. E., 1963, Telluriuma new sensitive test: Science, v. 141, no. 3575, 

p. 42-43. 

Lindgren, Waldemar, and Ransome, F. L., 19C'S, Geology and gold deposits of the Cripple Creek district, 

Colorado: U.S. Geol. Survey Prof. Paper 54, 516p. 

Loughlin, G. F., 1927, Ore at deep levels in the Cripple 

Creek district, Colorado: Am. Lnst. Minin~Metall. 

Engineers Tech. Pub. 13, 32 p. 

Loughlin, G. F., and Koschmann, A. H., 1935, Geology 

and ore deposits of the Cripple Creek dis t r i c t, 

Colorado: Colorado Sci. Soc. Proc., v. 13, no. 6, 

p. 217-435. 

Lovering, T. S., and Goddard, E. N., 1950, Geology 

and ore deposits of the Front Range, Colorado: 

U.S. Geol. Survey Prof. Paper 223, 319 p. 

Nakagawa, H. M., and Lakin, H. W., 1965, A field 

method for the determination of silver in soils and 

rocks, in Geological Survey research 19<--5: U.S. 

Geol. Survey. Prof. Paper 525-C, p. C172-CL75. 

Vaughn, W. W., and McCarthy, J. H., Jr., 1964, An 

instrumental technique for the determination of 

submicrogram concentrations of mercury in soils, 

rocks, and gas, in Geological Survey research 1964: 

3 

U.S. Geol. Survey Prof. Paper 501-D, p. 0123-

0127. 
4 

6 2 5 

10 

38° 

Tv 

..e' 14 13 18 . I~ 

~~ 

:· 

23 24 . • 19 •• 20 .... ., 

21 22 

.. ~· .: .. Tv 

. . •I . .. 

26 25 29 2.7 

Tv 

p£g 

31 32 . . 33 34 . . .... . 

. . . .. R.70W. R.69W. 

1 0 1 2 MILES 

Figure 2.-Map showing sampled localities (dots) and area of figures 3-7 (heavy rectangle). T•• Tertiary 

brecciated volcanic rocks; p(:g, Precambrian granite and some gneiss and schist. 

4 

T. 

18 

s. 
@ 

19 

@ 

30 

0 0 

20 

Cresson 

0 

0 

0 

0 

@ 

0 

0 1000 2000 FEET 

EXPLANATION 

0 • <0.1 ppm 

@ 

0.1-0.9 ppm 

• 1-1.9 ppm ~ 2 ppm 

Value shown if 

> 3 ppm 

Area within which the average concentration of 

gold in samples collected at each locality is 

I ppm or more 

Figure 3.-Gold distribution, average concentration at each locality. 

5 

N 
19 

0 

30 

0 0 

20 

Cresson 

0 

0 

@) 

0 @) 

29 

0 

0 1000 2000 FEET 

EXPLANATION 

0 • <0.1 ppm 

@ 

0.1-0.9 ppm 

~ 

1-1.9 ppm ~ 2 ppm Value sho~"'n if 

c:::J > 3 pp11 

Area within which the highest concentration 

of gold in samples collected at each 

locality is I ppm or more 

Figure 4.-Gold distribution, highest concentration at each locality. 

6 

N 
0 

0 0 

~ ~ 

19 20 

0 

30 

Cresson 

0 

0 

0 

@ 

0 1000 2000 FEET 

EXPLANATION 

0 • <0.5 ppm 

@ 

0.5-0.9 ppm 

• 1-9.9 ppm ~10 ppm 

c:::J 

Area within which the high:est concentration 

of silver in samples collected at each I oca1ity is I ppm or more 

Figure 5.-silver distribution. highest concentration at each locality. 

7 
19 

@ 

30 

0 

20 

0 

• 0 @ 29 

@ 

0 1000 2000 FEET 

EXPLANATION 

0 • <0.1 ppm 

@) 

0.1-0.9 ppm • 1-9.9 ppm ~ 10 pr71 

c:::J 

Value sho~"n if 

>tOO Pr'Tl 

Area within which the highest concentration 

of tellurium in samples collected at each 

locality is 10 ppm or more 

Figure G.-Tellurium distribution. highest concentration at each locality. 

8 

N 
® 

19 

0 

30 

0 ® 

@) ® 0 

0@ 0 @ 

@ 

0 

@ 20 

Cresson 

0 

0 0 

0 

@ @ 0 29 

0 

0 1000 2000 FEET 

EXPLANATION 

0 

<0.1 ppm 

@ 

0.1-0.9 ppm • 1-9.9 ppm • 10-100 ppm 

C:::J 

Area within which the highest concentration 

of mercury in samples collected at each 

locality is I ppm or more 

Figure 7.-Mercury distribution. highest concentration at each locality. 

r-

~ 

9 'k U. S. GOVERNMENT PRINTING OFFICE : 1968 0 - 329 ·504