Three Brothers Zone

Occurrence in King county in Washington, United States with commodities Copper, Molybdenum, Gold, Silver, Lead, Arsenic
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. Economic information about the deposit and operations
  15. Mining district
  16. Land status
  17. Ownership information
  18. Links to other databases
  19. Bibliographic references
  20. General comments
  21. Reporter information

Geologic information

Identification information

Deposit ID 10048444
MRDS ID MP00031
MAS/MILS ID 0530331236
Record type Site
Current site name Three Brothers Zone

Geographic coordinates

Geographic coordinates: -121.3456, 47.51792 (WGS84)
Elevation 1402
Location accuracy 1000(meters)
Relative position ABOUT 1.6 MI EAST OF BIG SNOW MOUNTAIN, Estimated From Map In Gualtieri And Others, Estimated From Map In Gualtieri And Others, Estimated From Map In Gualtieri And Others

Site location context

Political divisions (FIPS codes)

King(county)

Washington(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Big Snow Mountain(quadrangle 1:24,000 scale)

Skykomish River(quadrangle 1:100,000 scale)

Wenatchee(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Snoqualmie(hydrologic unit)

Puget Sound(hydrologic accounting unit)

Puget Sound(hydrologic subregion)

Pacific Northwest(hydrologic region)

Federal lands

Mt. Baker-Snoqualmie National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Washington King

Public Land Survey System information

Meridian Township Range Section Fraction State
Willamette 024N 012E 34 NEAR N BORDER Washington

Commodities

Commodity Importance
Copper Primary
Molybdenum Primary
Gold Tertiary
Silver Tertiary
Lead Tertiary
Arsenic Critical Tertiary

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Hematite Ore
Magnetite Ore
Molybdenite Ore
Pyrite Ore
Pyrrhotite Ore
Chlorite Gangue
Quartz Gangue
Siderite Gangue

Alteration

  • (Local) Potassic, Propylitic, Silicification

Analytical data

Result SEE DERKEY AND OTHERS (1990) FOR ANALYTICAL DATA FOR CLIPPER

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4

Host and associated rocks

  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Tonalite
    Rock unit name Snoqualmie Batholith, Northern Phase;Snoqualmie Batholith, Northern Phase
    Rock description Snoqualmie Batholith, Northern Phase;Snoqualmie Batholith, Northern Phase

Nearby scientific data

(1) -121.3456, 47.51792

Economic information

Geologic structures

Type of structure Regional
Structure description Part Of Ne-Trending En-Echelon Belt Of Nw-Striking Faults, Fractures, And Breccia Pipes
Type of structure Local
Structure description Brecciation Of Host Rocks

Ore body information

  • General form DISSEMINATED, STOCKWORK

Comments on the geologic information

  • GEOLOGY PRESUMED SAME AS AT CLIPPER

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic
Deposit size Small
Significant No

Mining district

District name Snoqualmie District

Land status

Ownership category National Forest
Area name In Snoqualmie National Forest Near Alpine Lakes Wilderness

Ownership information

  • Type Owner
    Owner United Cascade Mining Co., Inc.
    First year 1990

Comments on the workings information

  • ADIT

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit CONSIDERED PART OF CLIPPER BY DERKEY AND OTHERS (1990)
General Look at data in the Middle Fork Property file for more information. The Three Brothers is near the northern end of a string of mineralized, fractured zones, probably between the Hawk and Red Face zones.
Deposit DEPOSIT LIES BETWEEN TWO STEEPLY DIPPING FAULTS

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAY-91 Peterson, Jocelyn A. U.S. Geological Survey
Reporter 16-FEB-94 Thurber U.S. Bureau of Mines
Updater 18-MAY-09 Causey, J. Douglas U.S. Geological Survey

Beyond USGS

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