Mount Si

The Mount Si is a copper mine located in King county, Washington at an elevation of 4,239 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: Mount Si
Secondary: Bald Hornet Claims

Commodity

Primary: Copper

Location

State: Washington
County: King

Land Status

Land ownership: Private
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.

Holdings

Not available

Workings

Not available

Ownership

Owner Name: Weyerhaeuser Co.
Years: 1991 -

Owner Name: Duval Corp. (1970'S)

Production

Not available

Deposit

Record Type: Site
Operation Category: Occurrence
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

Not available

Orebody

Form: BRECCIA

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Plutonic Rocks Intensely Sericitized (Phyllic)

Rocks

Name: Diorite
Role: Associated
Age Type: Associated Rock
Age Young: Miocene

Name: Diorite
Role: Associated
Age Type: Host Rock
Age Young: Holocene

Name: Diorite
Role: Associated
Age Type: Host Rock Unit
Age Young: Holocene

Name: Diorite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Miocene

Analytical Data

Not available

Materials

Ore: Pyrite
Ore: Chalcopyrite
Gangue: Sericite
Gangue: Quartz
Gangue: Tourmaline

Comments

Comment (Location): MINERALIZED AREA IS EAST OF SUMMIT OF MOUNT SI. LOCATION GIVEN IS FOR TOURMALINE BRECCIA

Comment (Deposit): DEPOSIT HAS BEEN GIVEN THE INFORMAL NAME OF A BRECCIA PIPE CU DEPOSIT, FOR WHICH THERE IS NO PUBLISHED MODEL. QUARTZ-PYRITE-TOURMALINE VEINLETS. TOURMALINE VEINLETS ARE CUT BY LATER QUARTZ VEINLETS. TOURMALINE BRECCIA LOOKS LIKE COLLAPSE FEATURE IN HORNFELS. THERE ARE SEVERAL BRECCIA BODIES IN AREA

Comment (Workings): 15 WINKIE HOLES TOTALLING 1,500 FT, SOIL SAMPLING PROGRAM

Comment (Geology): HORNFELS PROTOLITH MAY HAVE BEEN PRE-TERT QUARTZITE AND SEDIMENTARY ROCKS

References

Reference (Deposit): ASHLEY, R.P., 1991, FIELD EXAM WITH GRANT NEWPORT OF WEYERHAUSER

Reference (Deposit): TABOR, R.W., FRIZZELL, V.A., JR., BOOTH, D.B., WHETTEN, J.T., WAITT, R.B., JR., AND ZARTMAN, R.E., 1982, PRELIMINARY GEOLOGIC MAP OF THE SKYKOMISH RIVER 1:100,000 QUADRANGLE, WASHINGTON: U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 82-747, SCALE 1:100,000.

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.