Hetta Mountain Prospects, Hetta Mountain, Prince of Wales Island, Ketchikan Mining District, Prince of Wales-Hyder Census Area, Alaska, USAi

Regional Level Types
Hetta Mountain Prospects	Group of Prospects
Hetta Mountain	Mountain
Prince of Wales Island	Island
Ketchikan Mining District	Mining District
Prince of Wales-Hyder Census Area	Census Area
Alaska	State
USA	Country

The 14 patented claims at this propect are surrounded by land whose surface and subsurface rights have been conveyed to, or are under application for transfer to, the Sealaska Corporation.
Location: These prospects are at an elevation of about 2,800 feet near the summit of Hetta Mountain; they are in the NW1/4 section 14, T. 77 S., R. 85 E.
Geology: The Hetta Mountain prospects are on 14 patented claims. The workings, all of which date from before WW I, consist of three short adits and several trenches (Wright and Wright,1908; Wright, 1915; Herreid and others, 1978; Maas and others, 1991, 1995). The rocks in the vicinity consist of a faulted-bounded block of Late Proterozoic or Cambrian marble of the Wales Group that is surrounded by Cretaceous, albite-epidote hornfels and garnet-bearing hornblende hornfels. The metamorphic rocks are cut by several granitic dikes, and the marble is locally altered to skarn. In one adit, a shear zone about 80 feet thick in marble contains diopside-garnet skarn with veinlets and blebs of chalcopyrite. In another adit, three short, en echelon pods of massive pyrite, pyrrhotite, and chalcopyrite replace marble along a porphyritic diorite dike (Herreid and others, 1978). A grab sample of rich ore contained 2.2 percent copper, 0.74 percent zinc, 12.3 ounces of silver per ton, 0.10 ounce of gold per ton, 600 parts per million (ppm) molybdenum, 750 ppm cobalt, and 22 ppm lead. Maas and others (1991) collected 15 samples from the prospects. Several had insignificant metal values, but the best contained 4.17 percent copper, 43.8 ppm silver, and 0.572 ppm gold. Wright and Wright (1908) show several additional prospects along the trail from the head of Copper Harbor to Hetta Mountain. At one, at an elevation of about 1,380 feet, a small mass of chalcopyrite is exposed in a 30-foot tunnel.
Workings: The Hetta Mountain prospects are on 14 patented claims. The workings, all of which date from before WW I, consist of three short adits and several trenches.
Age: Probably Cretaceous.
Alteration: Locally, skarn is developed in marble.

Commodities (Major) - Ag, Au, Cu, Fe, Zn; (Minor) - Co, Mo, Pb
Development Status: None
Deposit Model: Copper skarn (Singer and Cox, 1987; model 18b).

Other Databases

Link to USGS - Alaska:	CR157

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References