North Fork

The North Fork is a copper mine located in King county, Washington at an elevation of 3,501 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: North Fork
Secondary: Weyerhaeuser Land Prospect

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

Type: Patented

Workings

Not available

Ownership

Owner Name: Weyerhaeuser Co.
Percent: 100.0
Home Office: Washington
Info Year: 1974

Production

Not available

Deposit

Record Type: Deposit
Operation Category: Prospect
Deposit Type: Porphyry copper
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: STOCKWORK

Structure

Type: L
Description: Fractures

Alterations

Alteration Type: L
Alteration: Propylitic

Alteration Type: L
Alteration: Argillic

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

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Pyrrhotite
Ore: Chalcopyrite
Ore: Pyrite
Ore: Bornite
Gangue: Magnetite

Comments

Comment (Geology): SAID TO BE SIMILAR TO THE NORTH FORK DEPOSIT. INTRUSIVE ROCKS OF HOLLISTER ARE MAPPED AS ROCKS OF SNOQUALMIE BATHOLITH BY TABOR AND OTHERS. VOLCANIC ROCKS ARE CALLED VOLCANIC ROCKS OF MOUNT PERSIS BY TABOR AND OTHERS. VOLCANIC ROCKS ARE UNDERLAIN BY ROCKS OF THE WESTERN MELANGE BELT

Comment (Location): PARTLY WITHIN SOUTH FORK TOLT WATERSHED

Comment (Development): DEPOSIT HAS BEEN DRILLED ONLY

Comment (Workings): 26 DRILL HOLES

References

Reference (Reserve-Resource): HOLLISTER

Reference (Deposit): Washington Division of Mines and Geology IC 48, 1973, P. 19.

Reference (Geology): TABOR, R.W., FRIZZELL, V.A., JR., BOOTH, D.B., WAITT, R.B., JR., WHETTEN, J.T., AND ZARTMAN, R.E., 1993, GEOLOGIC MAP OF THE SKYKOMISH RIVER 30- by 60-MINUTE QUADRANGLE, WASHINGTON: U.S. GEOLOGICAL SURVEY MISCELLANEOUS INVESTIGATION SERIES MAP I-1963, SCALE 1:100,000.

Reference (Deposit): HOLLISTER, V.F., 1979, PORPHYRY COPPER-TYPE DEPOSITS OF THE CASCADE VOLCANIC ARC, WASHINGTON: MINERALS SCIENCE AND ENGINEERING, V. 11, P. 32-33.

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.