Boulder Creek

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Mo
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale GU
Quadrangle map, 1:63,360-scale D-1
Latitude 62.78
Longitude -144.01
Nearby scientific data Find additional scientific data near this location
Location and accuracy This placer (Cobb, 1979 [OF 79-1247 p. 6] is near the head of Boulder Creek (which is not named on the Gulkana D-1 quadrangle) at an elevation of about 3,800 feet. The prospect is about 1000 feet south of the center of section 36, T. 12 N., R. 7 E., Copper River Meridian. The prospect is shown as a placer on figure 5 of Richter (1966). It is shown as location 22 of Richter and Matson (1972) and locality 21 of MacKevett and Holloway (1977).

Geologic setting

Geologic description

Boulder Creek is mainly underlain by altered volcanic rocks of the Pennsylvanian to Permian, Tetelna Formation. The mine approximately coincides with a dike-like intrusion of Jurassic diorite which cuts the Tetelna Formation. The dike-like intrusion strike north-northwest for at least a mile (Richter 1966; Richter and Matson, 1968, figures 4-8; WGM, written communication. 1980). Stream sediment samples collected on the dike and below it in Boulder Creek were anomalous in gold. Richter and Matson (1968) also found somewhat anomalous amounts of molybdenum (6 to 11 ppm) in stream sediments collected on or near the dike.
Geologic map unit (-144.012190025537, 62.7796107274411)
Mineral deposit model Placer Au (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Holocene placer.

Production and reserves

Workings or exploration The area was prospected in the mid 1930s. Boulder Creek is almost certainly one of two unnamed gold-bearing creeks described briefly by Moffit (1938, p. 50-51) as 'two short streams that flow eastward from the divide at the head of Grubstake Creek into Porcupine Creek carry sufficient gold to encourage prospecting.' The other unnamed east-flowing auriferous creek is almost certainly Slope Creek (GU020). Moffit (1954, p. 195) also refers to easterly flowing, gold-bearing streams in the vicinity, one of which is probably Boulder Creek. Richter (1966) noted prospecting or small-scale placer mining in Boulder Creek.
Indication of production Yes; small
Production notes Probably some gold was recovered during prospecting activities at the head of Boulder Creek.

Additional comments

The association of stream sediment samples with anomalous gold and molybdenum near the elongate diorite pluton suggests that the intrusive and its contacts should be prospected for lode occurrences of gold and other metals.