Mag Deposit

Producer in Humboldt county in Nevada, United States with commodities Gold, Silver, Mercury, Arsenic, Antimony, Tungsten, Thallium, Barium-Barite, Fluorine-Fluorite, Molybdenum, Nickel, Zinc, Cobalt, Lead
Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Ownership information
  18. Reserves and resources
  19. Workings at the site
  20. Links to other databases
  21. Bibliographic references
  22. General comments
  23. Reporter information

Geologic information

Identification information

Deposit ID 10055089
MRDS ID RE00029
Record type Site
Current site name Mag Deposit

Geographic coordinates

Geographic coordinates: -117.25235, 41.13878 (WGS84)
Elevation 1524
Relative position 27 MILES NE OF WINNEMUCCA, NV.

Site location context

Political divisions (FIPS codes)

Humboldt(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Adam Peak(quadrangle 1:24,000 scale)

Osgood Mountains(quadrangle 1:100,000 scale)

McDermitt(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Middle Humboldt(hydrologic unit)

Humboldt(hydrologic accounting unit)

Black Rock Desert-Humboldt(hydrologic subregion)

Great Basin(hydrologic region)

Geographic areas

Country State County
United States Nevada Humboldt

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 38N 42E 28 Nevada

Comments on the location information

  • EAST FLANK OF OSGOOD MTNS.

Commodities

Commodity Importance
Gold Primary
Silver Secondary
Mercury Tertiary
Arsenic Critical Tertiary
Antimony Critical Tertiary
Tungsten Critical Tertiary
Thallium Tertiary
Barium-Barite Critical Tertiary
Fluorine-Fluorite Critical Tertiary
Molybdenum Tertiary
Nickel Critical Tertiary
Zinc Critical Tertiary
Cobalt Critical Tertiary
Lead Tertiary

Comments on the commodity information

  • AU CORRELATES STRONGLY WITH HG, TL, AND AS. AU CORRELATES WEAKLY WITH BA, ZN, AND F. AU DOES NOT CORRELATE WITH CO, CU, MO, NI, PB.

Materials information

Materials Type of material
Barite Gangue
Bournonite Gangue
Chalcopyrite Gangue
Cinnabar Gangue
Copper Gangue
Covellite Gangue
Famatinite Gangue
Galena Gangue
Geocronite Gangue
Iron Gangue
Marcasite Gangue
Pyrite Gangue
Quartz Gangue
Realgar Gangue
Sphalerite Gangue
Stibnite Gangue

Alteration

  • (Local) Hypogene Decalcification, Leaching, Silicification, Kaolinization Are Spatially Associated With Ore. Supergene Weathering Of Pyrite To A Depth Of 200 Ft. Calcite Veining Common Only In Massive, Unmineralized Limestone. Jasperoids Formed Coeval With Au Deposition, But Botryoidal, Chalcedonic Silica Is Younger Than Au Deposition.

Mineral occurrence model information

Model code 172
USGS model code 26a
Deposit model name Carbonate-hosted Au-Ag
Mark3 model number 15

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Argillite
    Rock unit name Comus Formation
    Rock description Comus Formation
    Stratigraphic age (youngest) Late Ordovician
    Stratigraphic age (youngest) Late Ordovician

Nearby scientific data

(1) -117.25235, 41.13878

Economic information

Geologic structures

Type of structure Local
Structure description Two Orientations Of Extensional Faulting Are Recognized. The Dominant Trend Strikes N-S To N30w, Dips 40-65 East, And Mimics The Strike Of The Orebody. The Second Strikes N30-60e, Dips 50-65 Se, And Offsets Quaternary Alluvium.

Ore body information

  • General form TABULAR
    Strike N20W
    Dip 45 EAST
    Thickness 121.92M

Controls for ore emplacement

  • Ne And Nw Striking Extensional Faults Are Structural Controls. Calcareous Argillite And Shale Of The Comus Formation Are The Stratigraphic Controls.

Economic information about the deposit and operations

Development status Producer
Commodity type Both
Deposit size Small
Significant No
Discovery year 1984
Discoverer Pinson Mining Co.
Year of first production 1987
Production years 1987 - PRESENT (12/91)

Mining district

District name Potosi District; Getchell Trend

Ownership information

  • Type Owner-Operator
    Owner Pinson Mining Co.
    Home office P.O. Box 192, Winnemucca, Nv 89445

Reserves and resources

  • Type Milling
    Estimate year 1989
    Commodity Subtype Grade units Group Importance Year
    Gold Au 2.258 g/mt Gold Major 1989
  • Type Leaching
    Estimate year 1989
    Commodity Subtype Grade units Group Importance Year
    Gold Au 0.847 g/mt Gold Major 1989

Comments on the reserve resource information

  • FIGURES REPRESENT PRE-MINING RESERVE ESTIMATES USING OVERALL STRIP RATIO OF 4:1. MILL CUTOFF GRADE IS 0.046 OPT AU. HEAP LEACH CUTOFF GRADE IS 0.020 OPT AU.

Workings at the site

  • Type of workings Surface
    Overall depth 54.86M
    Overall length 609.6M
    Overall width 274.32M

Comments on the workings information

  • FIGURES ABOVE ARE FOR AUGUST, 1989. WHEN COMPLETED IN 1998, PIT WILL BE 3200 FT. LONG, 1200 FT. WIDE, 500 FT. DEEP.

Comments on development

  • THE DEPOSIT WAS CONCEALED BY ALLUVIUM. IN 1971, A SOIL SAMPLING SURVEY DETECTED ELEVATED HG OVER MAG, BUT MAGNETIC AND VLF-EM SURVEYS GAVE UNCLEAR RESULTS. TWO HOLES WERE DRILLED NEAR MAG IN 1972 AS STEPOUTS ALONG STRIKE FROM THE PINSON A OREBODY. ONE OF THESE HOLES INTERSECTED MINOR AU MINERALIZATION. ADDITIONAL DRILLING IN THE 1970'S WAS COMPLETED FOR CLAIM ASSESSMENTS. IN 1978, ONE OF THESE HOLES INTERSECTED SIGNIFICANT LOW GRADE AU, BUT WAS NOT CONSIDERED ADEQUATE FOR IMMEDIATE FOLLOW-UP DRILLING. IN MAY, 1984, STEPOUT DRILLING DISCOVERED THE MAG DEPOSIT ALONG THE PINSON TREND AT THE INTERSECTION WITH N-NW STRIKING CARBONATE ROCKS. ; ECON.COM: MILL USES CARBON-IN-PULP PROCESS AT A RATE OF 1500 TONS PER DAY. MILL RECOVERIES OF 88% IN 1989; RECOVERIES WILL DECLINE AS CARBONACEOUS AND SULFIDE-BEARING ORE IS ENCOUNTERED WITH DEPTH.

Reference information

Bibliographic references

  • Deposit

    FOSTER, J.M., AND KRETSCHMER, E.L., 1991, GEOLOGY OF THE MAG DEPOSIT, PINSON MINE, HUMBOLDT COUNTY, NEVADA, IN RAINES, G.L., ET AL, EDS., GEOLOGY AND ORE DEPOSITS OF THE GREAT BASIN, THE GEOLOGICAL SOCIETY OF NEVADA, RENO, P. 845-856

General comments

Subject category Comment text
Deposit DEPOSIT THICKENS FROM 200 FT. IN NORTH-NORTHWEST TO 400 FT. IN SOUTH-SOUTHEAST.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-DEC-1991 Phinisey, J. D. (Marcus, S.) U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Authoritative Nevada resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.