M.G.L. Mines

Site Name

Primary: M.G.L. Mines
Secondary: Buster
Secondary: Cowles
Secondary: Western Soldier
Secondary: Wizard Group
Secondary: Cameron Claims
Secondary: NBMG Sample Sites 2896 and 2897

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Commodity

Primary: Tungsten
Tertiary: Molybdenum

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Location

State: Nevada
County: Pershing
District: Nightingale District

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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: Unknown

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Ownership

Owner Name: Mgl Mining Co.
Years: 1956 -

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Year First Production: 1918
Discovery Year: 1917
Years of Production:
Organization:
Significant: N
Deposit Size: S

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Physiography

Not available

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Mineral Deposit Model

Model Name: W skarn

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Orebody

Not available

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Structure

Type: L
Description: Post Mineral Faults

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Alterations

Alteration Type: L
Alteration Text: Silication And Silicification

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Rocks

Name: Diorite
Role: Associated
Age Type: Host Rock Unit
Age Young: Late Jurassic

Name: Diorite
Role: Associated
Age Type: Host Rock
Age Young: Late Jurassic

Name: Diorite
Role: Associated
Age Type: Associated Rock
Age Young: Late Cretaceous

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Analytical Data

Analytical Data: IT CONTAINS 3 % FE, 1 % MG, 15 % CA, 0.1 -% TI, 5000 PPM MN, 0.5 PPM AG, 10 PPM B, 15 PPM BI, 5 PPM CO, -50 PPM CR, 30 PPM CU, 30 PPM LA, 5 PPM NI, 20 PPM PB, 5 PPM SC-,20 PPM SN, 150 PPM V, 150 PPM W, 15 PPM Y, 50 PPM ZR.
Analytical Data: SAMPLE 2896, REDDISH-BROWN GARNET-SILICA ROCK TAKEN FROM THE OPEN STOPE AREA ON THE NORTH SIDE OF THE CANYON, CONT-AINS 3 % FE, 1.5 % MG, 15 % CA, 0.05 % TI, 5000 PPM MN, 500 PP-M B, 30 PPM BI, 5 PPM CO, 20 PPM CR, 10 PPM CU, 20 PPM LA, 5 P-PM NI, 15 PPM SN, 100 PPM SR, 100 PPM V, 150 PPM W, 10 PPM Y, -200 PPM ZN, 50 PPM ZR, (ALSO 0.05 PPM AU, BY AA ANALYSIS.) SAM-PLE 2897, CHIPPED FROM THE CONTACT ZONE ABOVE THE LARGE ADIT A-ND DUMP WITH SILICIC GARNET FROM A QUARTZITE WITH VISIBLE TUNG-STEN MINERALIZATION

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Materials

Ore: Scheelite
Ore: Molybdenite
Gangue: Quartz
Gangue: Pyrite
Gangue: Pyrrhotite
Gangue: Chalcopyrite
Gangue: Pyroxene
Gangue: Calcite
Gangue: Garnet
Gangue: Epidote

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Comments

Comment (Deposit): -SIX PRINCIPAL OREBODIES WERE MINED. THE LARGEST WAS IN THAT SO-UTH ROTATED BLOCK OF LIMESTONE. AT THE SURFACE, THIS BLOCK WAS- SURROUNDED BY HIGHLY QUARTZOSE TACTITE, 5-20 FT THICK, CONSIS-TING OF 70-90 % QUARTZ AND 10-30 % EPIDOTE, PYROXENE, HORNBLEN-DE AND GARNET WITH SMALL QUANTITIES OF SULFIDES. BETWEEN THIS -LAYER AND THE CENTRAL CORE OF MARBLE WAS A BAND OF SCHEELITE-B-EARING TACTITE ON THE SOUTH, WEST, AND NORTH SIDES OF THE BLOC-K. IN DEPTH, THE SCHEELITE-BEARING TACTITE THICKENED AT THE EX-PENSE OF THE MARBLE AND ABOUT 100 FT BENEATH THE OUTCROP, THE -MARBLE WAS REPLACED BY ORE ACROSS THE FULL WIDTH. AT 150 FT, T-HE ORE WAS CUT OFF BY GRANODIORITE. THE ORE MINED CONTAINED 0.-75 TO 1.0 % WO3. OTHER SMALLER OREBODIES TO THE NORTH ALSO CON-SISTED OF RIMS OF TACTITE ABOUT 5 FT WIDE AROUND CORES OF MARB-LE, SEPARATED FROM EACH OTHER BY TONGUES OF GRANODIORITE.

Comment (Workings): SEVERAL LARGE ADITS NORTH OF THE CANYON AND OPEN STOPE. MILL SITE AT THE MOUTH OF THE CANYON; RAISES, DRIFTS

Comment (Geology): AREAS OF SCHIST AND SLATE ARE INVADED BY GRANODIORITE TONGUES PARALLEL TO BEDDING. LIMESTONE (MARBLE AND HORNFELS) ARE CUT INTO IRREGULAR-SHAPED BLOCKS BY GRANODIORITE DIKES. SCHEELITE SEEN IS PURE WHITE AND LESS THAN A 1/4 INCH THICK. DEPOSITS CARRY CONSIDERABLE GARNET IN CONTRAST TO DEPOSITS ON EASTERN SLOPE OF NIGHTINGALE RANGE. W DEPOSITS IN TACTITES AT LIMESTONE/GRANODIORITE CONTACT. SCHEELITE CONCENTRATION VARY IN ALTERNATING LAYERS.

Comment (Deposit): AT SEVERAL PLACES 0.5 TO 1.0 MILE EAST OF THE M. G. L. MINE, SCHEELITE IS FOUND IN SMALL TACTITE INCLUSIONS IN GRA-NODIORITE WITHIN A FEW HUNDRED FEET OF THE MAIN MASS OF SEDIME-NTARY ROCKS. THESE INCLUSIONS ARE ALL SHALLOW, AS INDICATED BY- DIAMOND DRILLING BY THE M.G.L. MINING CORP., AND CONTAINED ON-LY A FEW HUNDRED TONS EACH OF MINEABLE ORE, MOST OF THIS ORE W-AS PROBABLY MINED DURING THE 1953-1956 PERIOD. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT; 3 FIELD OBSERV

Comment (Location): ON WEST FLANK OF NIGHTINGALE RANGE

Comment (Production): W AS WO3; BY 1956

Comment (Development): SMALL AMOUNT OF ORE PRODUCED IN 1917-18. FROM 1942-45 THE MINE WAS OPERATED BY THE M.G.L. MINING CORP WHICH BUILT A 100-TON FLOTATION CONCENTRATOR. THE MINE WAS REOPENED DURING 1952-56 AND WORKED BY VARIOUS LESSEES. IT HAS BEEN IDLE SINCE 1956.FIRST PRODUCTION IN 1918 BY C. R. COWLES AND ASSOCIATES, WHO MINED ABOUT 80 TONS THAT AVERAGED 1.28 % WO3. THE PRO-PERTY WAS ACQUIRED BY THE M.G.L. MINING CORP. IN 1941 AND A MI-LL WAS BUILT AT THE MOUTH OF COWLES CANYON. MOST OF THE PRODUC-TION WAS DURING WORLD WAR II (1942-1945). A SMALL PRODUCTION W-AS REPORTED IN 1953-56 AND INCLUDED SEVERAL HUNDRED UNITS FROM- REWORKED TAILINGS. RECENTLY OVERSTAKED(?)(1985).BEFORE THE MINE WAS CLOSED IN 1945, THE OPERATORS DRILLED 82 DIAMOND DRILL HOLES TO EXPLORE TME AREA AND DELINEAT-E THE ORE BODIES. THIS EXPLORATION DID NOT DISCOVER ANY ADDITI-ONAL OREBODIES THAT COULD BE MINED PROFITABLY IN 1945.

Comment (Deposit): CONTACT ZONE IS BETWEEN A THICK SEQUENCE OF ARGILLACEOUS AND CALCAREOUS SEDIMENTARY ROCKS AND AN INTRUSIVE BODY OF- GRANODIORITE. THE CONTACT IS NEARLY CONFORMABLE BUT THE CONTA-CT ZONE IS INTRICATELY INJECTED BY GRANODIORITE, RESULTING IN -MIXED ROCKS. THE CENTRAL PART OF THE CONTACT ZONE CONSISTS OF -A BAND OF LIMESTONE ABOUT 80 FT WIDE, PARTIALLY ALTERED TO TAC-TITE. THE ROCKS ON EITHER SIDE ARE HORNFELS OR SCHIST, MIXED W-ITH GRANODIORITE. AT DEPTHS OF A FEW HUNDRED FEET, THE GRANODI-ORITE CUTS ACROSS THE SEDIMENTARY ROCKS AND CUTS OFF THE FAVOR-ABLE LIMESTONE BEDS. IN MOST OF THE CONTACT ZONE, BEDDING IS P-ARALLEL TO THAT IN THE MAIN MASS OF SEDIMENTARY ROCKS TO THE S-OUTHWEST. HOWEVER, AT THE SOUTH END OF THE MINE, AN IRREGULAR -BLOCK OF LIMESTONE ABOUT 80 FT WIDE AND 120 FT LONG, ENTIRELY -SURROUNDED BY GRANODIORITE AT THE SURFACE, HAS BEEN ROTATED 45- DEGREES. THIS BLOCK APPARENTLY FLOATED AS AN INCLUSION IN THE- GRANODIORITE AND NOT ONLY ROTATED, BUT ALSO MOVED 100 FT SW.

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References

Reference (Deposit): JOHNSON, M.G., 1977, GEOLOGY AND MINERAL DEPOSITS OF PERSHING COUNTY, NEVADA: NBMG BULL. 89

Reference (Deposit): JOHNSON AND BENSON, 1963, TUNGSTEN RESOURCES OF NEVADA: USBM REPORT

Reference (Deposit): HESS AND LARSEN, 1921, CONTACT-METAMORPHIC TUNGSTEN DEPOSITS OF THE U.S.; USGS BULL. 725-D

Reference (Deposit): KERR, 1946, TUNGSTEN MINERALIZATION IN THE UNITED STTATES: GSA MEMOIR 15

Reference (Deposit): VANDERBURG, 1936, RECONNAISSANCE OF MINING DISTRICTS IN PERSHING COUNTY; USBM 1C 6902.

Reference (Deposit): STAGER, H. K., IN PREPARATION, NBMG BULL ON TUNGSTEN DEPOSITS OF NEVADA.

Reference (Deposit): QUADE, JACK, 1 MAR 85, NBMG FIELD EXAMINATION AND SAMPLE ANALYSIS.

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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.