California-Alaska

Mine, Inactive

Alternative names

Falls Creek

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Pb; Zn
Ore minerals arsenopyrite; chalcopyrite; galena; gold; pyrite; pyrrhotite; sphalerite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-7
Latitude 60.4295
Longitude -149.2784
Nearby scientific data Find additional scientific data near this location
Location and accuracy The mine is located on Falls Creek at an elevation of 2,100 feet. It is situated near the north boundary of the NE1/4 section 21, T. 4 N., R. 1 E., of the Seward Meridian. This is location 72 of Cobb and Tysdal (1980) and location S-224 of Jansons and others (1984). This location is accurate to within 300 feet.

Geologic setting

Geologic description

The mine worked a quartz-calcite vein in a shear zone that also contains gouge. The vein is between 8 inches and 4 feet wide within a 5-foot-wide shear zone that strikes N50E and dips northeast. The host rock consists of tightly folded slate and graywacke that strike north to northeast and dip 75 to 90E (Brooks, 1911 [B 480-B, p. 32]). Nelson and others (1985) mapped this area as shale and graywacke of the Valdez Group of Late Cretaceous age.
The vein is composed of massive white quartz with a minor amount of calcite. Arsenopyrite is the principal sulfide in the wall rock and in the vein. Other sulfides include chalcopyrite, galena, pyrrhotite, pyrite, and sphalerite. Brooks (1911 [B 480-B]) noted that gold appeared to be concentrated in a bluish quartz.
Recorded production totalled 65 ounces of gold and 13 ounces of silver (Hoekzema and Sherman, 1983).
Geologic map unit (-149.280520978107, 60.428921988651)
Mineral deposit model Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Cretaceous or younger; the vein cuts rocks of the Valdez Group of Late Cretaceous age.

Production and reserves

Workings or exploration
Workings total about 860 feet of adit, drift, and winze. Hoekzema and Sherman (1983) reported that the workings were inaccessible; however, the portal below the falls was opened in the early 1990s by the current mining claimants. It is only a few feet above the creek level. Improvements consisted of two 2-stamp mills, a Chilean mill, and a crusher powered by a Pelton water wheel operating under 80-foot head of water from Falls Creek (Brooks, 1911 [B 480-B, p. 32]). The remains of a ball mill can be seen several hundred feet upstream from the stamp mills. The 3.5-mile-long mine road was usable by all-terrain vehicles (ATVs) in 2000; the road begins at Crown Point, across the highway from the Trail River campground road.
The gold was reported to be free milling and averaged between $30 and $40 to the ton in gold (gold at $20.67 per ounce) (Brooks, 1911 [B 480-B]). A 6-foot chip sample collected by the U.S. Bureau of Mines from the vein exposed on the surface assayed 0.09 ounce of gold per ton and 0.07 ounce of silver per ton (Jansons and others, 1984).
Indication of production Yes; small
Production notes Total recorded production is 65 ounces of gold and 13 ounces of silver (Hoekzema and Sherman, 1983). Some of this may have come from the Skeen-Lechner mine, SR207, because both were operated by the same company.

References

MRDS Number A010357

References

Hoekzema, R.P., and Sherman, G.E., 1983, Mineral investigations in the Chugach National Forest, Alaska (Peninsula study area): U.S. Bureau of Mines in-house report; held at U.S. Bureau of Land Management Alaska State Office, Anchorage, 524 p.
Reporters Jeff A. Huber and Carol S. Huber (Anchorage)
Last report date 7/23/2001