Pioneer Gulch

Mine, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Ore minerals arsenopyrite; gold; pyrite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale NM
Quadrangle map, 1:63,360-scale C-1
Latitude 64.6953
Longitude -165.4203
Nearby scientific data Find additional scientific data near this location
Location and accuracy This partly residual, alluvial placer gold mine is in Pioneer Gulch, a small west tributary to upper Snake River on the east side of hill 1276. The map site is in the NW1/4 section 23, T. 9 S., R. 34 W., Kateel River Meridian. It includes localities 35 and 90 of Cobb (1972 [MF 463], 1978 [OFR 78-93]) and locality 14 of Hummel (1962 [MF 247]).

Geologic setting

Geologic description

A partly residual alluvial gold placer was mined in Pioneer Gulch as early as 1903 (Collier and others, 1908). Its discovery must have occurred early in the history of the Nome District because a 4.5 mile-long ditch had been constructed from Last Chance Creek to Pioneer Gulch by September of 1903 (Collier and others, 1908, p. 183). The placer gold was coarse and angular, and some had attached quartz fragments (Moffit, 1913). Prospecting for lode deposits, including at least one shaft, identified narrow limonitic calcite-quartz veins containing pyrite, arsenopyrite, and free gold (Cathcart, 1922). Gold-bearing quartz veins were exposed on the property in 1992. The veins cut graphitic schist that probably has an early Paleozoic protolith age (Hummel, 1962 [MF 247]; Sainsbury, Hummel, and Hudson, 1972 [OFR 72-326]; Till and Dumoulin, 1994; Bundtzen and others, 1994).
Geologic map unit (-165.42291560044, 64.6945365177566)
Mineral deposit model Alluvial placer Au, in part residual, and low-sulfide Au-quartz veins (Cox and Singer, 1986; models 39a and 36a).
Mineral deposit model number 39a and 36a
Age of mineralization Quaternary; veins are mid-Cretaceous or younger because they cut schist metamorphosed in the mid-Cretaceous.

Production and reserves

Workings or exploration Surface mining of alluvial placer deposits commenced in 1903, and a residual placer deposit was mined by 1913. Hard rock exploration, including at least one shaft, was reported by Cathcart (1922).
Indication of production Yes; small

References

MRDS Number A012819; A012878

References

Till, A.B., and Dumoulin, J.A, 1994, Geology of Seward Peninsula and St. Lawrence Island, in Plafker, G., and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, v. G-1, p. 141-152.
Reporters C.C. Hawley and Travis L. Hudson
Last report date 7/10/2000