Buffalo Valley Mine

Site Name

Primary: Buffalo Valley Mine

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Commodity

Primary: Silver
Primary: Gold
Secondary: Copper
Tertiary: Arsenic
Tertiary: Nickel

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Location

State: Nevada
County: Lander
District: Buffalo Valley; Battle Mountain; Mill Canyon

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Land Status

Land ownership: BLM Administrative Area
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

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Holdings

Not available

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Workings

Type: Surface/Underground

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Ownership

Owner Name: Buffalo Valley Mines Co.
Years: 1941 -

Owner Name: Buffalo Valley Mines Co. ; Horizon Gold Shares Inc.
Years: 1941 -

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Production

Year: 1988
Material type: ORE-AU
Description: Ap_Grade: ^0.0299 Opt Au
Year: 1987
Material type: ORE-AU
Description: Ap_Grade: ^0.0573 Opt Au

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Deposit

Record Type: Site
Operation Category: Producer
Operation Type: Unknown
Year First Production: 1924
Year Last Production: 1990
Discovery Year: 1916
Discovery Method: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S

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Physiography

General Physiographic Area: Intermontane Plateaus
Physiographic Province: Basin And Range Province
Physiographic Section: Great Basin
Physiographic Detail: Basin And Mountains

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Mineral Deposit Model

Model Name: Skarn Au

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Orebody

Form: TABULAR

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Structure

Type: R
Description: Golconda Thrust

Type: L
Description: The Havallah Sequence Of The Buffalo Valley Mine Has A Homoclinal Appearance. With Certain Exceptions, Beds Strike Nw To Slightly East Of North And Generally Dip 45-65 Sw Or West. Buffalo Valley Mine Is Situated In A Fault Block That Is Bounded On The East By The Western Range-Bounding Fault Of Battle Mountain And On The West By Another West-Dipping Normal Fault, Which Is Known In Mine Terminology As The Front Fault.

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Alterations

Alteration Type: L
Alteration Text: Contact Metamorphism, Endoskarn, Potassic Alteration, Prograde Skarn, Retrograde Skarn. See Geology Comments.

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Rocks

Name: Alluvium
Role: Associated
Age Type: Host Rock Unit
Age Young: Late Permian

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Analytical Data

Not available

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Materials

Ore: Malachite
Ore: Chalcopyrite
Ore: Limonite
Ore: Chrysocolla
Ore: Hematite
Ore: Gold
Gangue: Clinozoisite
Gangue: Diopside
Gangue: Quartz
Gangue: Epidote
Gangue: Biotite

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Comments

Comment (Geology): PROGRADE SKARN: A FEW UNEQUIVOCAL BUT RARE EXAMPLES OF COARSE GRAINED GARNET-PYROXENE SKARN HAVE BEEN EXPOSED IN THE CENTER OF THE OPEN PIT, INTERBEDDED WITH CALC-SILICATE HORNFELS. THESE SKARNS CONTAIN PYRITE, ALTHOUGH IT IS UNCLEAR WHETHER IT WAS DEPOSITED SYNCHRONOUS WITH SKARN SILICATES. RETROGRADE SKARN: PYROXENE HORNFELS AND LESS COMMONLY BASALT AND BIOTITE HORNFELS LOCALLY ARE INTENSELY ALTERED TO DARK GREEN CHLORITE, PYRITE, AND NONTRONITE(?). THIS ASSEMBLGE HAS BEEN REPORTED TO CARRY FREE GOLD. GEOLOGY COMMENTS: ROCKS OF THE HAVALLAH SEQUENCE IN THE BUFFALO VALLEY MINE AREA CAN BE GROUPED INTO 3 LOCAL UNITS (AND THEIR METAMORPHIC AND METASOMATIC EQUIVALENTS): 1) A LOWER STRUCTURAL UNIT CONSISTING OF CHERT, LESSER SHALE AND SILTSTONE, MINOR PEBBLY SANDSTONE RICH IN BLACK CHERT CLASTS, AND MINOR LIMESTONE; 2) A SILL OR LAVA FLOW OF FINE GRAINED BASALT; AND 3) AN UPPER STRUCTURAL UNIT CONSISTING OF NON-CALCAREOUS TO WEAKLY CALCAREOUS SILTSTONE, QUARTZITE, AND SHALE. THE

Comment (Geology): ALTERATION COMMENTS: CONTACT METAMORPHISM: IN THE UPPER STRUCTURAL UNIT OF THE HAVALLAH SEQUENCE, NON-CALCAREOUS SILTY LITHOLOGIES ARE CONVERTED TO BIOTITE HORNFELS; SLIGHTLY CALCAREOUS, SILICEOUS AND ARGILLACEOUS SILTSTONES ARE METAMORPHOSED TO CALC-SILICATE HORNFELSES (DIOPSIDE + QUARTZ PLAGIOCLASE, CLINOZOISITE, EPIDOTE). SULFIDES ARE RESTRICTED TO LATER FRACTURES. ENDOSKARN: SULFIDE-POOR CALC-SILICATE MINERAL ASSEMBLAGES WHICH OCCUR AS ALTERATION PRODUCTS OF PORPHYRY DIKES ARE COMMON WEST AND SOUTHWEST OF THE OPEN PIT, RARE IN THE OPEN PIT, AND ABSENT EAST AND NORTH OF THE PIT. IN SOME HAND SPECIMENS, ENDOSKARN ALTERATION CAN BE OBSERVED AS ENVELOPES ABOUT INDIVIDUAL QUARTZ VEINS, E.G. PLAGIOCLASE-QUARTZ-PYROXENE-BEARING INNER ENVELOPES (HORNBLENDE DESTROYED) AND RELICT HORNBLENDE-STABLE OUTER ENVELOPES. POTASSIC ALTERATION: SHREDDY HYDOTHERMAL BIOTITE IS ABUNDANT IN DIKES IN THE OPEN PIT AND THE DEGREE OF BIOTIZATION IS INDEPENDENT OF PROXIMITY TO QUARTZ VEINS.

Comment (Geology): BASALT AND UPPER STRUCTURAL UNIT ARE EXPOSED IN THE PIT. VARIABLY ALTERED GRANODIORITIC PORPHYRY DIKES INTRUDE THE HAVALLAH SEQUENCE ROCKS THROUGHOUT THE MINE AREA AND ARE INTERPRETED TO BE PART OF A LATE EOCENE(?) PORPHYRY SYSTEM, INFERRED TO BE RELATED TO A LARGER SUBJACENT PLUTON. SOME DIKES CARRY ANOMALOUS AU VALUES, INDICATING AU DEPOSITION POST-DATES INTRUSION OF THE DIKES. UNALTERED, UNMINERALIZED INTERCALATED ASH FLOW TUFFS AND ALLUVIUM OVERLIE THE HAVALLAH SEQUENCE ROCKS AND DIKES. BASED ON THE SPATIAL CORRESPONDENCE OF AU-BEARING PYRITIC VEINS WITH THE SWARM OF DIKES IN THE PIT AND THE PRESENCE OF MINOR AU OCCURRENCES ASSOCIATED WITH OUTLYING PORPHYRY DIKES, SEEDORFF (1991) SUGGESTS THAT AU DEPOSITION IS RELATED TO THE COPPER CANYON PORPHYRY SYSTEM.

Comment (Development): INCH PRIOR TO STACKING ON THE HEAP LEACH PADS. AT THE TIME OF SUSPENSION OF FULL SCALE OPERATIONS ON OCTOBER 1, 1990, MINING CAPACITY WAS 1900 TPD. DORE BARS PRODUCED AT BUFFALO VALLEY MINE AVERAGED 66% AU, 11% AG, 19% CU, AND 4% OTHER IMPURITIES, INCLUDING NI. ORE CRUSHING WAS DONE BY A CONTRACT CRUSHER. AU RECOVERY FACILITIES WERE CONSTRUCTED ON THE PROPERTY AND CONSISTED OF 8 ONE-HALF-TON EDUCTION CARBON COLUMNS, 5 ONE-TON FIXED BED CARBON TANKS, 2 PRESSURIZED STRIPPING TANKS, AND 4 ELECTROLYTIC RECOVERY CELLS. THESE FACILITIES WERE CAPABLE OF TREATING 850 GALLONS OF PREGNANT SOLUTION PER MINUTE FROM THE HEAP LEACH PAD.

Comment (Deposit): THE OREBODIES MINED UNDERGROUND ASSOCIATED WITH THE FRONT FAULT STRIKE N18E AND DIP 40-55W. THE DEPOSIT DEVELOPED BY OPEN PIT STRIKES N30W AND TRUNCATES AGAINST THE FRONT FAULT.

Comment (Workings): HISTORIC UNDERGROUND WORKINGS AGGREGATE 3000 FT. AND INCLUDE 5 ADITS, ONE OF WHICH IS 600 FT. LONG AND ANOTHER 400 FT. LONG. IN ADDITION, 40 SHALLOW PITS AND TRENCHES HAVE BEEN DUG ON THE SURFACE. THREE LEVELS, CONNECTED BY STOPES AND RAISES, AND AN INCLINED SHAFT WHICH EXTENDS 220 FT. BELOW THE SURFACE CONSTITUTE THE MAIN UNDERGROUND WORKINGS. OVERALL DIMENSIONS AND DEPTH GIVEN ABOVE ARE FOR THE ULTIMATE PIT AS PLANNED IN 1988. THE LAND POSITION CONTROLLED BY HORIZON GOLD AT THE BUFFALO VALLEY MINE AND SURROUNDING ACREAGE TOTALS OVER 18,000 ACRES.

Comment (Development): AS RUN-OF-MINE MATERIAL AND WAS LOADED ON THE LEACH PAD UNCRUSHED; WASTE WAS CLASSIFIED AS ANYTHING GRADING <0.012 OPT AU. CONSTRUCTION AND START UP COSTS AT THE MINE WERE LESS THAN $1.5 MILLION. CASH OPERATING COSTS PER OUNCE OF AU SOLD AVERAGED $175 FOR FISCAL 86/87, $250 FOR FISCAL 87/88, $246 FOR FISCAL 89/90, AND $227 FOR THE PERIOD JUNE 1, 1986 TO SEPTEMBER 30, 1990 (START UP TO SHUT DOWN). AVERAGE PRODUCTION COST PER OUNCE OF AU SOLD, INCLUDING DEPRECIATION AND DEPLETION, WAS $321 FOR THE PERIOD JUNE 1, 1986 TO SEPTEMBER 30, 1990. HORIZON OWNS A 100% WORKING INTEREST IN THE PROPERTY AND IS OPERATING UNDER A LEASE AGREEMENT WITH ROYALTIES VARYING FROM 4% TO 7.5% OF GROSS PROCEEDS, DEPENDING ON REALIZED AU PRICES. MOST METALLURGICAL TESTS HAVE RETURNED SODIUM CYANIDE AU LEACH RECOVERIES RANGING FROM 65%-75% OF THE CONTAINED AU WITHIN 60-120 DAYS OF STANDARD HEAP LEACHING TECHNIQUES, ALTHOUGH TYPICAL RECOVERIES AT THE MINE WERE 80%. BUFFALO VALLEY MINE ORE WAS CRUSHED TO MINUS ONE

Comment (Development): 214 ROTARY DRILL HOLES, OVER 3000 AU ASSAYS COLLECTED FROM SURFACE, UNDERGROUND, AND DRILL HOLE SAMPLES, SURFACE AND UNDERGROUND GEOLOGIC MAPPING, AND METALLURIGICAL AND FEASIBILITY STUDIES. HORIZON MINED THE BUFFALO VALLEY DEPOSIT AS AN OPEN PIT-HEAP LEACH OPERATION DURING THE PERIOD JUNE 1, 1986 TO OCTOBER 1, 1990. IN DECEMBER, 1988, HORIZON FORMED A JOINT VENTURE WITH CHEVRON RESOURCES COMPANY TO EXPLORE THE BUFFALO VALLEY PROPERTY. AS OF NOVEMBER 1989, THE HORIZON/CHEVRON VENTURE HAD DISCOVERED ADDITIONAL NEAR SURFACE AU OCCURRENCES IN OXIDIZED VEINS TO THE NORTH, SOUTHWEST, AND EAST OF THE OPEN PIT AND HAD IDENTIFIED AN UNDERGROUND RESOURCE IN AU-BEARING OXIDIZED VEINS BENEATH THE EXISTING PIT. TOTAL$: <1.5; MILL.CAP: 850 GALLONS/MI N.; ECON.YEAR: 1986. ; ECON.COM: HORIZON USED THREE GRADE CATEGORIES DURING OPEN PIT MINING/HEAP LEACHING: NUMBER ONE ROCK (>/= 0.015 OPT AU) WAS CRUSHED PRIOR TO LOADING ON THE HEAP LEACH PAD; NUMBER TWO ROCK (>/= 0.012 AND <0.015 OPT AU) WAS TREATED

Comment (Development): PROSPECTING IN THE AREA OF THE BUFFALO VALLEY MINE BEGAN IN THE 1860'S WITH THE DISCOVERY OF AU PLACERS. IN 1916, BUFFALO VALLEY MINES CO. PURCHASED FROM C. GANSER AND OTHERS 28 UNPATENTED CLAIMS WHICH WERE THEN DEVELOPED AS THE UNDERGROUND MINE. PRODUCTION WAS ALMOST CONTINUOUS FROM 1924 TO 1941, AND ALSO IN 1951. A 10-TON CYANIDIZATION PLANT WAS BUILT IN 1925 AND 1196 TONS OF ORE WERE TREATED BY 1933. TOTAL REPORTED PRODUCTION THROUGH 1951 WAS APPROXIMATELY 3000 TONS. NUMEROUS INDEPENDENT EXPLORATION COMPANIES EXPLORED THE BUFFALO VALLEY MINE FROM THE MID-1960'S TO 1985. IN 1985, HORIZON GOLD SHARES INC. ACQUIRED A 99 YEAR MINING LEASE ON 158 UNPATENTED MINING CLAIMS AT THE BUFFALO VALLEY MINE. HORIZON THEN EXPANDED THEIR LAND POSITION BY LOCATING AN ADDITIONAL 679 UNPATENTED CLAIMS. AT THE TIME OF HORIZON'S ACQUISITION OF THE PROPERTY, THERE EXISTED A DATABASE COLLECTED FROM PREVIOUS EXPLORATION EFFORTS THAT CONSISTED OF OVER 200 SHORT PERCUSSION DRILL HOLES, 7 DIAMOND DRILL HOLES,

Comment (Deposit): DO NOT CONFUSE THIS DEPOSIT WITH THE BUFFALO VALLEY MOLYBDENUM PROSPECT THAT LIES 7 KM TO THE SOUTH AT THE SW TIP OF BATTLE MOUNTAIN IN SECS. 21 AND 28T31N, R42E (NO MRDS RECORD). THIS RECORD HAS BEEN MERGED WITH DATA FROM RECORD #M233793, WHICH HAS BEEN DELETED.

Comment (Commodity): ROBERTS AND ARNOLD (1965) REPORT THE PRESENCE OF A VEIN CONTAINING PYRITE AND CHALCOPYRITE 800 FT. SE OF THE HISTORIC WORKINGS WHICH ASSAYS UP TO 2.0 OZ/TON AU; THIS IS LIKELY IN THE AREA WHICH HAS BEEN DEVELOPED AS AN OPEN PIT. ACCORDING TO SHIPMENT RECORDS FROM 1924-1951, THE AU AND AG CONTENT OF THE ORE INCREASES WITH AN INCREASE IN COPPER.

Comment (Location): UTM'S TO SHAFTS OF HISTORIC UNDERGROUND WORKINGS AT NORTH END OF CURRENT OPEN PIT. LOCATED BETWEEN TIMBER AND MILL CANYONS.; PREVIOUS QUAD DESIGNATION = WINNEMUCCA (1971) 1:250000

Comment (Production): HORIZON GOLD SHARES FISCAL YEAR ENDS MARCH 31. 1986-1990 CUMULATIVE PRODUCTION FIGURES REPRESENT THE PERIOD FROM THE INITIATION OF OPEN PIT MINING ON JUNE 1, 1986 TO THE DECISION TO SUSPEND MINING AND LEACHING OPERATIONS ON OCTOBER 1, 1990.

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References

Reference (Deposit): HORIZON GOLD SHARES INC., ANNUAL REPORT FOR 1988.

Reference (Deposit): HORIZON GOLD SHARES INC., ANNUAL REPORT FOR 1989.

Reference (Deposit): HORIZON GOLD SHARES INC., FORM 10-K FOR 1990.

Reference (Deposit): ROBERTS, R.J., AND ARNOLD, D.C., ORE DEPOSITS OF THE ANTLER PEAK QUADRANGLE, HUMBOLDT AND LANDER COUNTIES, NEVADA: U.S.G.S. PROF PAPER 459-B.

Reference (Deposit): QUADE, J./ BENTZ, J.; FIELD EXAM MAY 11, 1982

Reference (Deposit): SEEDORFF, E., BAILEY, C. R. G., KELLEY, D., AND PARKS, W., 1991, BUFFALO VALLEY MINE: A PORPHYRY-RELATED GOLD DEPOSIT, LANDER COUNTY, NEVADA, IN BUFFA, R. AND COYNER, A., EDS., GEOLOGY AND ORE DEPOSITS OF THE GREAT BASIN - FIELD TRIP GUIDEBOOK COMPENDIUM, THE GEOLOGICAL SOCIETY OF NEVADA, RENO, P. 969-987.

Reference (Deposit): HORIZON GOLD SHARES INC., ANNUAL REPORT FOR 1987.

Reference (Deposit): HORIZON GOLD SHARES INC., FORM 10-K FOR 1991.

Reference (Deposit): NBMG, 1994, MI-1993

Reference (Production): ANNUAL PRODUCTION FOR FISCAL YEARS 1986/87, 1987/88, 1988/89: HORIZON GOLD SHARES INC., ANNUAL REPORT FOR 1989. 1924-1951 CUMULATIVE PRODUCTION: ROBERTS, R.J., AND ARNOLD, D.C., ORE DEPOSITS OF THE ANTLER PEAK QUADRANGLE, HUMBOLDT AND LANDER COUNTIES, NEVADA: U.S.G.S. PROF PAPER 459-B. 1986-1990 CUMULATIVE PRODUCTION: HORIZON GOLD SHARES INC., FORM 10-K FOR 1991. MI-1993

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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.