Mineral Investigations in the Koyukuk Mining District, Northern Alaska - Volumes 1 and 2 and Map
From 1997 to 2002, the Bureau of Land Management (BLM) conducted a mineral resource investigation of the Koyukuk Mining District in northern Alaska. The 11.6-million-acre study area comprises the upper portion of the Koyukuk River drainage basin. The objective of the investigation was to identify the nature and extent of mineral resources in the district. Field work consisted of mapping and sampling mines, prospects, and mineral occurrences and reconnaissance sampling in areas containing no documented sites. A total of 2,098 rock, soil, stream sediment, and concentrate samples were collected during the study. This investigation is part of the Bureau’s ongoing statewide mining district assessment program.
The BLM identified a total of 269 mines, prospects, and mineral occurrences within or directly adjacent to the district. This includes 27 previously undocumented occurrences. Deposit types include gold and tin placers; antimony- and gold-bearing quartz veins; stratabound, carbonate-hosted, and volcanogenic massive sulfides; copper porphyries; copper, tungsten, and tin skarns; tin greisens; podiform chromite; and coal. Documented production totals 333,893 oz of placer gold. Resource estimates include a measured resource of 33,600 oz of placer gold in the Nolan-Hammond River area, an indicated resource of 2.3 million lbs of placer tin on the Kanuti Kilolitna River, an indicated resource of 1.1 million tons averaging 5.0% copper in skarn deposits near the Bettles River, and an indicated resource of 31,000 tons averaging 39.4 ppm gold in quartz veins on Sukakpak Mountain.
Other significant results from this investigation include the delineation of anomalous gold values within volcanic rocks on the upper Indian River; anomalous placer gold in bench gravels on the upper Hammond River; gold-bearing quartz veinlets on nearby Vermont and Smith Creeks; anomalous goldbearing gravels on Black and Davis Creeks and Ironsides Bench; potential for significant amounts of placer gold in buried channels near Linda Creek; and gold anomalies associated with skarn and massive sulfide occurrences in the Chandalar copper belt north of Bettles River.