South Bullion Deposit

Site Name

Primary: South Bullion Deposit

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Commodity

Primary: Gold
Primary: Silver
Tertiary: Molybdenum
Tertiary: Mercury
Tertiary: Thallium
Tertiary: Arsenic
Tertiary: Antimony

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Location

State: Nevada
County: Elko
District: Bullion; Railroad; Carlin Trend

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Land Status

Not available

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Holdings

Not available

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Workings

Not available

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Ownership

Owner Name: Newmont Exploration, Ltd.

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Prospect
Deposit Type: Replacement
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: M

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Physiography

Not available

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Mineral Deposit Model

Model Name: Carbonate-hosted Au-Ag

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Orebody

Form: TABULAR

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Structure

Type: R
Description: N-Trending Anticline That Forms The Crest Of The Pinon Range.

Type: L
Description: Numerous High-Angle, Generally West-Dipping, N25w Oriented Faults.

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Alterations

Alteration Type: L
Alteration Text: Silicification, Decalcification, Liesegang Banding, Argillization. See Geology Comments.

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Rocks

Name: Mudstone
Role: Host
Age Type: Host Rock
Age Young: Mississippian

Name: Mudstone
Role: Host
Age Type: Host Rock Unit
Age Young: Mississippian

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Analytical Data

Analytical Data: PATHFINDER ELEMENTS ASSOCIATED WITH AU INCLUDE AS (TO 2600 PPM), AG (TO 49 PPM), SB (TO 1190 PPM), HG (TO 7 PPM), TL (TO 14 PPM), AND MO (TO 17 PPM). AU HAS A WEAK ASSOCIATION WITH BASE METALS AND CALCITE.

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Materials

Gangue: Jarosite
Gangue: Barite
Gangue: Calcite
Gangue: Stibnite
Gangue: Pyrite

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Comments

Comment (Development): SUCCESSFUL DRILLING AT THE RAIN DEPOSIT IN 1980 SPURRED NEWMONT'S EXPLORATION ACTIVITY ELSEWHERE IN THE PINON RANGE, BEGINNING WITH A REGIONAL STREAM SEDIMENT GEOCHEMICAL SAMPLING PROGRAM. NUMEROUS GEOCHEMICAL ANOMALIES WERE IDENTIFIED, ONE OF WHICH WAS SOURCED UP THE TROUT CREEK DRAINAGE. FOLLOW-UP PROSPECTING IDENTIFIED BARITIC, JASPEROIDAL WEBB FORMATION IN SEC. 21 AT WHAT WOULD COME TO BE IDENTIFIED AS THE TROUT CREEK DEPOSIT (RECORD #RE00044). DURING 1980, NEWMONT LOCATED CLAIMS IN SECTIONS 20 AND 28, AND IN 1982 COMPLETED 19 REVERSE CIRCULATION DRILL HOLES WITHIN SEC. 20. THE BEST INTERCEPT WAS 1.5 METERS/0.02 OPT AU IN REALGAR- AND ORPIMENT-BEARING CHAINMAN SHALE FROM HOLE NSB-15. THE TARGETED WEBB FORMATION WAS NOT INTERSECTED IN ANY OF THESE HOLES, AND NEWMONT CONTROL OF THE PROPERTIES WAS RELINQUISHED. DURING LATE 1986, NEWMONT RECOGNIZED POTENTIAL DOWNDIP FROM THE TROUT CREEK DEPOSIT IN SEC. 27 AND ACQUISITION OF SURFACE AND MINERAL RIGHTS BEGAN THERE IN 1987. A 7 HOLE

Comment (Development): DRILLING PROGRAM IN LATE 1987 INTERSECTED STRONGLY MINERALIZED WEBB FORMATION AT SHALLOW DEPTH. AN ADDITIONAL 41 HOLES WERE DRILLED ON APPROXIMATELY 122 M CENTERS IN 1988. WITH ADDITIONAL DRILLING IN 1989, A TOTAL OF 65 REVERSE CIRCULATION DRILL HOLES HAD BEEN COMPLETED THROUGH THAT YEAR, IDENTIFYING A DRILL-INFERRED GEOLOGIC RESOURCE TOTALLING APPROXIMATELY 20 MILLION SHORT TONS AVERAGING 0,026 OPT AU.

Comment (Geology): SUGGESTED BY THE PRESENCE OF DISPERSED HYDROTHERMAL CLAYS WITHIN THE WEBB FORMATION AND THE CHAINMAN SHALE AT BOTH THE LOCAL AND DISTRICT SCALES. DUE TO THE REGIONAL EXTENT OF THE CLAYS, AS CONTRASTED TO THE LIMITED AREA OF GOLD MINERALIZATION, THE GOLD IS THOUGHT TO NOT NECESSARILY BE TEMPORALLY ASSOCIATED WITH THIS WEAK ARGILLIZATION EVENT. GEOLOGY COMMENTS: THE DEPOSIT LIES WITHIN THE PINON RANGE WHICH OCCURS WITHIN THE NARROW N-S TRENDING BELT WHICH COINCIDES WITH THE POSITION OF THE PALEOZOIC CONTINENTAL MARGIN.

Comment (Location): LOCATED ON THE WEST FLANK OF THE PINON RANGE. THE SOUTH BULLION DEPOSIT IS THE SOUTHERN PORTION OF A SINGLE HYDROTHERMAL SYSTEM, THE NORTHERN PORTION OF WHICH IS THE TROUT CREEK DEPOSIT (RECORD #RE00044). THE PROPERTY BOUNDARY BETWEEN TROUT CREEK AND SOUTH BULLION DEPOSITS IS THE SECTION LINE BETWEEN SECTIONS 22 AND 27, T30N, R53E.

Comment (Geology): ALTERATION COMMENTS: SILICIFICATION, DECALCIFICATION, ARGILLIZATION. GOLD MINERALIZATION IS INTIMATELY RELATED, BOTH TEMPORALLY AND SPATIALLY, TO SILICIFICATION OF THE WEBB FORMATION. SILICIFICATION OF THE WEBB FORMATION HAS RESULTED IN 1) REPLACEMENT OF PRIMARY CALCAREOUS MATERIAL BY AUTHIGENIC QUARTZ, FORMING THE MAJOR PORTION OF THE FINE GRAINED JASPEROID, 2) DEVELOPMENT OF QUARTZ OVERGROWTHS, SOME OF WHICH ARE MULTIPLE OVERGROWTHS, 3) THE IN-FILLING OF FRACTURES AND VUGS BY COARSE ANHEDRAL AND EUHEDRAL QUARTZ, AND 4) PERVASIVE SILICA FLOODING ALONG ZONES OF INDUCED SECONDARY POROSITY AND PERMEABILITY. PORTIONS OF THE WEBB FORMATION AND DEVILS GATE LIMESTONE ARE DECALCIFIED IN AN ENVELOPE TO THE JASPEROID. AN UNSILICIFIED PORTION OF THE WEBB FORMATION THAT DIRECTLY OVERLIES THE JASPEROID CONTAINS NUMEROUS FINE CALCITE VEINLETS; A SIMILAR ZONE OCCURS DIRECTLY BELOW THE JASPEROID AND IS CHARACTERIZED BY MASSIVE VEIN- AND CAVITY-FILLING SPARRY CALCITE. WEAK ARGILLIC ALTERATION IS

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References

Reference (Deposit): PUTNAM, B. R., AND HENRIQUES, E. Q. B., 1991, GEOLOGY AND MINERALIZATION AT THE SOUTH BULLION DEPOSIT, PINON RANGE, ELKO COUNTY, NEVADA: IMPLICATIONS FOR WESTERN UNITED STATES CENOZOIC TECTONICS, IN RAINES, G. L., ET AL, EDS., GEOLOGY AND ORE DEPOSITS OF THE GREAT BASIN, THE GEOLOGICAL SOCIETY OF NEVADA, RENO, P. 713-728

Reference (Analytical Data): PUTNAM, B. R., AND HENRIQUES, E. Q. B., 1991, GEOLOGY AND MINERALIZATION AT THE SOUTH BULLION DEPOSIT, PINON RANGE, ELKO COUNTY, NEVADA: IMPLICATIONS FOR WESTERN UNITED STATES CENOZOIC TECTONICS, IN RAINES, G. L., ET AL, EDS., GEOLOGY AND ORE DEPOSITS OF THE GREAT BASIN, THE GEOLOGICAL SOCIETY OF NEVADA, RENO, P. 713-728.

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Nevada Gold

Nevada has a total of 368 distinct gold districts. Of the of those, just 36 are major producers with production and/or reserves of over 1,000,000 ounces, 49 have production and/or reserves of over 100,000 ounces, with the rest having less than 100,000 ounces. Read more: Gold Districts of Nevada.