Upper Chisna River Prospects, Chistochina Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
Upper Chisna River Prospects	Group of Prospects
Chistochina Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

Location: This record is a general location for unpatented mining claims along about 6 miles of the Chisna River above Red Mountain Creek and below Ruby Gulch (Rose, 1967). The site is plotted about one-half mile below the mouth of Powell Gulch, about the center of the claims. It is accurate as a general location for claims that have been prospected since the early days of the district (Mendenhall and Schrader, 1903).
Geology: The Chisna River below Ruby Gulch and above Red Mountain Creek flows through a rather wide glacial valley. Except for recent alluvium along the river, the gravel consists mainly of glacial outwash and till. The river has been claimed and explored at intervals since gold was discovered in 1898. Fine gold is concentrated on clay layers within the glacial deposits but is not abundant enough to be mined (Mendenhall and Schrader, 1903). A shaft sunk in the valley about one-half mile above Powell Gulch penetrated about 20 feet of till before entering a wet sand alluvial deposit, where the shaft collapsed. Partly on the basis of results of drilling in Upper Slate Creek (MH298), it is likely that the valley of the Chisna has deeply incised channels in bedrock that may be auriferous. At times when the mouth of Slate Creek was dammed by a glacier in the main Chistochina River valley, ice and outwash must have flowed down the Chisna River valley and introduced gold from upstream sources. No deep gold resources have been identified, but they probably exist. Most gold in the district is accompanied by large amounts of magnetite and some garnet and pyrite. Platinum group elements (PGEs) were found in the Upper Slate Creek deposit (MH298) and could exist in the Chisna River gravels derived from Slate Creek.
Workings: The upper Chisna River has been prospected since the discovery of gold near Chisna in 1898. No significant mining has occurred in the river above the Chisna mine site (MH356).
Age: Pleistocene.

Commodities (Major) - Au; (Minor) - Ag, platinum group elements (PGE) (?)
Development Status: Undetermined.
Deposit Model: Placer Au-PGE (Cox and Singer, 1986; model 39a).

Other Databases

Link to USGS - Alaska:	MH301

Other Regions, Features and Areas containing this locality

References