Grass Gulch

Mine, Probably inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale NM
Quadrangle map, 1:63,360-scale C-1
Latitude 64.5779
Longitude -165.3492
Nearby scientific data Find additional scientific data near this location
Location and accuracy This alluvial placer gold mine is in Grass Gulch, a west headwater tributary to Dexter Creek (NM303). The map location is at an elevation of about 450 feet in the SW1/4 section 31, T. 10 S., R. 33 W., Kateel River Meridian. Grass Gulch is included in locality 118 of Cobb (1972 [MF 463], 1978 [OFR 78-93]).

Geologic setting

Geologic description

Grass Gulch is one of several small headwater tributaries of Dexter Creek (NM303) that head in areas where high-level auriferous gravels have been mined (for example, NM246 and NM247). The Grass Gulch placer was small but very rich, and the entire 15 feet of rounded-pebble gravel and some clay was gold-bearing. The deposit apparently was worked out by 1903 from a 150-foot by 300- or 400-foot pit (Collier and others, 1908). Gold was also recovered from fractured and creviced marble bedrock. Overburden was only 2 feet of moss and soil, some of the gravel was frozen, and granite clasts were uncommon in the gravel (Collier and others, 1908; Moffit, 1913). Much of the placer gold in the headwaters of Dexter Creek, including Grass Gulch, is probably derived from reworking of the high-level gravels.
Geologic map unit (-165.351806730713, 64.5771360557321)
Mineral deposit model Alluvial placer Au (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration A 150-foot by 300- or 400-foot pit removed the main deposit by 1903 and most of the rest of the deposit was mined out by 1909 (Collier and others, 1908; Henshaw, 1910).
Indication of production Yes; small