Three Brothers Zone

The Three Brothers Zone is a molybdenum and copper mine located in King county, Washington at an elevation of 4,600 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.

Site Name

Primary: Three Brothers Zone

Commodity

Primary: Molybdenum
Primary: Copper
Tertiary: Lead
Tertiary: Arsenic
Tertiary: Gold
Tertiary: Silver

Location

State: Washington
County: King
District: Snoqualmie District

Land Status

Land ownership: National Forest
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.
Administrative Organization: In Snoqualmie National Forest Near Alpine Lakes Wilderness

Holdings

Not available

Workings

Not available

Ownership

Owner Name: United Cascade Mining Co., Inc.
Years: 1990 -

Production

Not available

Deposit

Record Type: Site
Operation Category: Occurrence
Deposit Type: porphyry Cu
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Pacific Mountain System
Physiographic Province: Cascade-Sierra Mountains
Physiographic Section: Northern Cascade Mountains

Mineral Deposit Model

Model Name: Porphyry Cu

Orebody

Form: DISSEMINATED, STOCKWORK

Structure

Type: R
Description: Part Of Ne-Trending En-Echelon Belt Of Nw-Striking Faults, Fractures, And Breccia Pipes

Type: L
Description: Brecciation Of Host Rocks

Alterations

Alteration Type: L
Alteration Text: Potassic, Propylitic, Silicification

Rocks

Not available

Analytical Data

Analytical Data: SEE DERKEY AND OTHERS (1990) FOR ANALYTICAL DATA FOR CLIPPER

Materials

Ore: Pyrrhotite
Ore: Chalcopyrite
Ore: Galena
Ore: Molybdenite
Ore: Pyrite
Ore: Magnetite
Ore: Hematite
Gangue: Quartz
Gangue: Siderite
Gangue: Chlorite

Comments

Comment (Workings): ADIT

Comment (Geology): GEOLOGY PRESUMED SAME AS AT CLIPPER

Comment (Deposit): CONSIDERED PART OF CLIPPER BY DERKEY AND OTHERS (1990)

Comment (Deposit): DEPOSIT LIES BETWEEN TWO STEEPLY DIPPING FAULTS

Comment (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.

References

Reference (Deposit): U.S. GEOLOGICAL SURVEY BULLETIN 1542-E, 1989, FIG. 11, P. 98; P. 101-102.

Reference (Deposit): GUALTIERI, J.L., THURBER, H.K., MILLER, M.S., MCMAHAN, A.B., AND FEDERSPIEL, F.F., 1975, MINERAL RESOURCES OF ADDITIONS TO THE ALPINE LAKES STUDY AREA, CHELAN, KING, AND KITTITAS COUNTIES, WASHINGTON: U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 75-3, P. 51-61.

Reference (Deposit): DERKEY, R.E., JOSEPH, N.L., AND LASMANIS, RAYMOND, 1990, METAL MINES OF WASHINGTON - PRELIMINARY REPORT: WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES OPEN-FILE REPORT 90-18, P. 109-110.

Reference (Deposit): GUALTIERI, J.L., SIMMONS, G.C., THURBER, H.K., AND MILLER, M.S., 1973, MINERAL RESOURCES OF THE ALPINE LAKES STUDY AREA, CHELAN, KING, AND KITTITAS COUNTIES, WASHINGTON: U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 1918, P. 71-74.

Reference (Deposit): HOLLISTER, V.F., 1979, PROPHYRY COPPER-TYPE DEPOSITS OF THE CASCADE VOLCANIC ARC, WASHINGTON: MINERALS SCIENCE AND ENGINEERING, V. 11, P. 32.

Washington Gold

"Where to Find Gold in Washington" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in Arizona. Read more: Where to Find Gold in Washington.