Clipper Prospects, Middle Fork of the Snoqualmie River, Snoqualmie Mining District, King County, Washington, USAi

Regional Level Types
Clipper Prospects	Prospect
Middle Fork of the Snoqualmie River	River
Snoqualmie Mining District	Mining District
King County	County (Historical)
Washington	State
USA	Country

The Clipper prospects are one of the few developed copper operations on the Middle Fork Snoqualmie River. The deposits were supposedly discovered around the turn of the century. This group was comprised of 15 patented claims and 14 unpatented claims that were the original holdings of the Snoqualmie Copper co and the Clipper Mining co. Several thousand feet of core was drilled, but there is no reported production. The zone was reported to have contained 250,000 tons of rock containing 0.9% copper and around 0.1% molybdenum. Later work around the 1960s-1980s failed to find enough ore to justify the large scale mining operation. The wilderness designation around it made the project even less feasible.

The mineralization occurs as disseminated sulfides in brecciated granite.
Tectonics: Part Of A Northeast-Trending Belt Of En Echelon (Nw-Striking) Faults, Fractures, And Breccia Pipes Defining A Porphyry Copper System.

Commodity: Area has peripheral pb and zn mineralization. Insignificant Au and w.

Deposit: On the last chance claim, a 390-ft. Adit bearing n40 W intersects mineralization from 265 to 310 ft.; the area was stoped. On the pedro claim, a 10-ft. Adit was driven in a 50-ft.-wide mineralized zone. On the katie belle and tracy claims, a 15-ft. Adit and a 100-plus-ft. Adit were driven. Both the patented and unpatented claims are owned (1990) by united cascade mining co., inc. Companies who have explored the deposit include anaconda copper co., howe sound co., climax molybdenum corp., anaconda co., bear corp., houston oil and minerals, and electras resources. ; info.src : 1 pub lit

Deposit type: Porphyry Cu

Development: Econ.com: test stope 25 ft. By 35 ft. Long; ore stockpiled on dump. Over the years has been explored by many mining companies

Geology: The clipper deposit is in the snoqualmie batholith, northern phase granodiorite and tonalite with biotite and hornblende; locally it contains clinopyroxene. The rocks are light colored, medium crystalline, and mostly equigranular and have hypidiomorphic texture, and are coarsely jointed. Age of the northern phase is about 25 m.y. Based on interpretation of numerous discordant k-ar ages of both hornblende and biotite (tabor and others, 1982, p. 8). Grant (1969) indicates there were two stages of mineralization tourmaline breccia pipes are altered and mineralized in addition to the disseminated and stockwork mineralization

Ore(s): See Comments

Other Databases

Link to USGS MRDS:	10055922

Other Regions, Features and Areas containing this locality

References