Mattie (lower workings)

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 64.5892
Longitude -165.3526
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Mattie placer mine is at an elevation of about 575 feet on the north side of the divide between Nekula Gulch in the south headwaters of Anvil Creek (NM236) and Deer Gulch in the north headwaters of Dexter Creek (NM303). The map location is in the SW1/4 section 30, T. 10 S., R. 33 W., Kateel River Meridian. It was included in locality 117 (Dexter Hill) of Cobb (1972 [MF 463], 1978 [OFR 78-93]).

Geologic setting

Geologic description

The Mattie 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 locally were very rich (Brooks and others, 1901). The richest pay was near bedrock and in decomposed or fractured bedrock. The high-level gravels were mined mostly by drifting, but some hydraulic mining also took place. An hydraulic cut at the Mattie mine exposed 5 to 6 feet of sandy wash and pebbles overlying 25 feet of stratified gravel and clayey sediment. The bright and not-waterworn gold was concentrated on bedrock and in the top several feet of creviced bedrock; about 0.45 ounce of gold per cubic yard was recovered in 1900 (Collier and others, 1908). The high-level gravels were originally interpreted as 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 the exotic clasts are commonly in near-surface materials and not distributed throughout the high-level gravels (Moffit, 1913). The origin of the high-level gravels thus still seems in question. 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 Hopkins, 1972 [OFR 72-326]; Till and Dumoulin, 1994; Bundtzen and others, 1994).
Geologic map unit (-165.355208055527, 64.588436188376)
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 Surface workings at the Mattie mine included a 50- by 150-foot hydraulic cut that was excavated to a depth of 30 feet. About 0.45 ounce of gold per cubic yard was recovered in 1900 (Collier and others, 1908).
Indication of production Yes; small
Production notes Production from the high-level gravels of the general area totaled about 100,000 ounces by 1903 (Collier and others, 1908).

References

MRDS Number A012929

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