Centennial Ridge District

Queen mine on Centennial Ridge.
Queen mine on Centennial Ridge.

Placer gold, discovered in gravels along the Middle Fork of the Little Laramie River, led to the organization of the Centennial Ridge mining district in the east-central Medicine Bow Mountains in 1876. Placer activity was followed by several lode discoveries including the Centennial mine. A new wave of prospecting and development followed the 1901 discovery of platinum associated with copper ores at the New Rambler mine five miles to the southwest. Structural fabric within the district is generally northeast-trending and parallel to the Cheyenne belt. Lode mineralization includes foliation/schistosity parallel gold-bearing quartz veins in biotite and hornblende gneisses and schists, and gold-platinum fracture-filling and replacement veins in shear zones and faults cutting the gneisses and schists. Sulfides and arsenides accompany gold-platinum in the fracture fillings. Sulfide-rich zones, dominated by pyrite and occurring in mafic host rocks, usually accompany the richest ores in the district. Actual production from the Centennial Ridge district is unknown. However, the Centennial Mine produced an estimated 4,500 ounces of gold (Hausel, 1989).

Further information on the Centennial Ridge district can be found in the following WSGS publication:

WSGS Pre­liminary Report 7, The Centennial Ridge gold-platinum district, Albany County, Wyoming, by M.E. McCallum (1968), map scale 1:20,000, 12 p.