Trinity Mine, Phelps Ridge (Red Mountain), Chiwawa Mining District, Chelan County, Washington, USAi

Regional Level Types
Trinity Mine	Mine
Phelps Ridge (Red Mountain)	Ridge
Chiwawa Mining District	Mining District
Chelan County	County
Washington	State
USA	Country

A copper mine located in secs. 15, 21 & 22, T30N, R15E, WM, at the S end of Phelps Ridge (Red Mountain), on private (patented) land within a National Forest. The location is set at the portal of the St. Francis tunnel, which overlies the ore body. This mine was discovered in the early 1890's. Owned by the Crater Mining Company, Washington (1967). Owned by Two Rivers, Incorporated (1979). Operated by the American Exploration and Mining Company, Washington (1967). The USGS MRDS database stated accuracy for this locality is 10-100 meters.

Mineralization occurs most extensively in a brecciated zone between Swakane Biotite Gneiss and an unnamed diorite. This deposit has been given the informal name of a breccia pipe Cu deposit, for there is no published model. The breccia zone is 250 feet wide at the gneiss-diorite contact. Mineralization is most extensive in the brecciated zone between the Swakane Biotite Gneiss and diorite. Sulfide minerals are chiefly pyrrhotite and chalcopyrite. Scheelite occurs as disseminated grains, veinlets, and small masses in the sulfides (Culver and Broughton, 1945, P. 14-15). Local alteration is propylitic. Local rocks include Pre-Upper Jurassic gneiss.

Age of the host rocks and mineralization is very uncertain. The host rocks were metamorphosed after 415 MA. Mineralization is probably younger than 415 MA. Radiometric ages on zircons from the Swakane Biotite Gneiss indicate an age for metamorphism of 415 MY and formation ages of 1,650 MY or more (Mattinson, 1972, P. 3773). The age and nature of the diorite are unknown.

Workings include surface and underground openings with a length of 3,566.16 meters and comprised of numerous prospect pits, the 1,500 foot Leprechaun adit, 11,000 foot Trinity adit, 850 feet of raises, the 650 foot St. Francis adit, the 280 foot T.A.K. adit, the 200 foot LD adit, a 40 foot discovery adit, a newer adit, unknown length, several drifts, four production levels and interconnected stopes. The Trinity tunnel accesses the ore body from 2 miles away and is at the site of the old mill facility, now destroyed.

It was originally known as the Bryan group and was minimally developed by the Una Mining Company. Later on, it was taken on by the Royal Development company and extensively developed. It produced more than 15,000 tons of ore from 1930, 1935-1937, and 1940. As of 1982 18,000 tons had been produced. No W production.

Analytical data results: TR - 1.93% Cu, 0.61-5.38 ounces Ag/ton, a little Au.

Other Databases

Link to USGS MRDS:	10008893
Link to USGS MRDS:	10055848
Link to USGS MRDS:	10228080

Other Regions, Features and Areas containing this locality

References