Greenhorn Gulch

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale CI
Quadrangle map, 1:63,360-scale B-3
Latitude 65.451
Longitude -145.071
Nearby scientific data Find additional scientific data near this location
Location and accuracy Greenhorn Gulch extends about 1.5 mi north and 1.5 mi south of the coordinate intersection; it is a tributary of Boulder Creek. Mining activity in the 1970's and 1980's also has occurred at the junction with Tinhorn Gulch.

Geologic setting

Geologic description

The creek along Greenhorn Gulch flows north for approximately 5 km before joining Boulder Creek. Bedrock throughout the entire Greenhorn Gulch drainage is the Lower Schist unit described by Wiltse and others (1995) as slightly calcareous quartz-muscovite schist, porphyroblastic albite-quartz-chlorite-muscovite schist, and lesser amounts of quartzose porphyroblastic albite-chlorite schist and chlorite schist.
An alluvium-covered bench on the west side of the gulch is 8 to 12 m above the valley bottom and grades into the bench in Boulder Creek. The creek gravel in Greenhorn Gulch is composed of boulders up to 70 cm in diameter, but are more commonly 10 to 30 cm across. The gravel is 1 to 2 meters thick over the schist bedrock and is as much as 30 meters wide (Yeend, 1991). A fragment of vein quartz with cavities from which sulfides had been weathered out assayed 24 oz. silver per ton and contained specks of free gold (Spurr, 1898, p. 293).
Geologic map unit (-145.07344881544, 65.4506310342245)
Mineral deposit model Placer gold deposit (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a

Production and reserves

Workings or exploration There was small-scale placer mining reported in 1896, and 1911 to 1912; however, mining was hampered by the lack of water. Recent mining activity in the 1970s and 1980s has occurred on the creek junction with Tinhorn Gulch (Yeend, 1991; Menzie and others, 1983).
Indication of production Yes; small
Production notes A 2.5 oz gold nugget was recovered in the early days of mining, and vein quartz in the gravel reportedly contained finely disseminated free gold (Spurr, 1898).

Additional comments

Greenhorn Gulch is the only part of the Boulder Creek drainage that has had significant placer mining activity. Greenhorn Gulch has also been called Greenhorn Creek but it should not be confused with the much less productive 'Greenhorn Creek' that is a tributary of Bottom Dollar Creek.

References

MRDS Number A012232

References

Reporters C.J. Freeman, J.R. Guidetti Schaefer, A.S. Clements (Avalon Development Corporation)
Last report date 9/9/1998