Caribou Bill

Mine, 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 64.5897
Longitude -165.357
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Caribou Bill placer mine is at an elevation of about 500 feet in Nekula Gulch, about 4,400 feet southwest of the summit of King Mountain. Nekula Gulch is in the south-side headwaters of Anvil Creek (NM236). The map location is in the SW1/4 section 30, T. 10 S., R. 33 W., Kateel River Meridian. It is included in locality 117 (Dexter Hill) of Cobb (1972 [MF 463], 1978 [OFR 78-93]).

Geologic setting

Geologic description

The Caribou Bill mine is one of several near the divide between upper Anvil Creek (NM236) and Dexter Creek (NM303) at surface elevations of about 450 to 600 feet, where high-level gravels were placer mined for gold. These deposits were in gravels that ranged from a few feet to 150 feet thick and commonly were very rich (Brooks and others, 1901). The richest pay was near bedrock and in decomposed or fractured bedrock. The Caribou Bill mine also had very rich pay in what is probably a karst-related solution pit or cavern 90 feet deep in marble; the slightly rounded schist and marble pebble gravels (cemented with yellow clay) contained as much as 48 ounces of coarse and angular gold per cubic yard (Collier and others, 1908). The high-level gravels were mined mostly by drifting, but some hydraulic mining also took place. The high-level gravels were originally interpreted to be alluvial deposits in stream channels of former drainage systems, but more recent interpretations describe them as glacial outwash-related material (Cobb, 1973 [B 1374]; Nelson and Hopkins, 1972). The presence of erratic granite boulders and other exotic rock types suggests a glacial origin, but such clasts are mostly in near-surface materials and not distributed throughout the high-level gravels (Moffit, 1913). The origin of the high-level gravels thus seems in question still. The richness of some of the placers suggests extensive reworking, proximity to lode sources, or both.
The Anvil fault transects the area near Nekula Gulch. The Anvil fault is a through-going, high-angle structure that juxtaposes different types of graphitic schist in this area (Hummel, 1962 [MF 247]). Bedrock is mostly graphitic schist, probably of 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 (-165.359608086152, 64.5889360876693)
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 The Caribou Bill deposit was mined in a surface pit that was 30 by 50 feet across and 20 feet deep in 1902-03; a 90-foot shaft was used to recover rich pay from what is probably a solution cavity in marble (Collier and others, 1908). Possibly the deposit was a gigantic pothole.
Indication of production Yes; small
Production notes The Caribou Bill deposit was very rich consisting of gravels containing as much as 48 ounces of gold per cubic yard. The gold was coarse and angular and thought to be locally derived. Production from the high-level gravels of the general area totaled about 100,000 ounces by 1903 (Collier and others, 1908).

References

MRDS Number A012928

References

Brooks, A.H., Richardson, G.B., Collier, A.J., and W.C. Mendenhall, 1901, A reconnaissance in the Cape Nome and adjacent gold fields of Seward Peninsula, Alaska, in 1900: U.S. Geological Survey Special Publication, p. 1-185, maps.
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