Mineral Occurrence and Development Potential Report, Locatable and Salable Minerals, Bering Sea-Western Interior Resource Management Plan
The Anchorage Field Office of the Bureau of Land Management (BLM) is preparing the Bering Sea–Western Interior (BSWI) Resource Management Plan (RMP) to provide a comprehensive framework for managing and allocating uses of public lands and resources in the central southwestern portion of the State of Alaska. The BSWI Planning Area encompasses nearly 60 million acres, with 13 percent of those lands managed by the BLM. An analysis of the locatable and salable mineral potential within the BSWI Planning Area was completed as part of this study. The main objective was to delineate areas with high potential for the development of locatable and salable minerals.
The BSWI Planning Area has a long and colorful mining history, dating back to the late 1830s when Russian traders discovered mercury-bearing minerals along the Kuskokwim River near Aniak. This was the site of one of the last great gold rushes in Alaska when gold was discovered in the Flat area in 1908. Documented mineral production within the planning area totals 3.2 million oz gold, 151,750 oz silver, 2.1 million lbs of copper, and 41,767 flasks of mercury. The Iditarod Mining District, which includes the Flat area, ranks 3rd in placer gold production in Alaska.
The planning area contains 445 documented mineral occurrences. This includes placer gold, gold-bearing quartz veins, copper-gold skarns, and silica-carbonate mercury deposits. The area currently contains a total of 6,618 mining claims with 219 of those under federal management. In 2008 there were nine active placer mines and one active lode mine within the planning area.
There are several sites within the planning area containing mineral resources. At the Donlin felsic-dike-hosted gold deposit, measured/indicated resources total 94.6 million tons at an average grade of 0.06 oz/ton gold. Additional inferred resources place total contained metal at 29.3 million oz gold. At the Nixon copper-gold skarn deposit measured/indicated resources total 164,639 tons at an average grade of 0.70 oz/ton gold along with an undisclosed amount of copper and silver.
The present study focused on locating and evaluating mineral occurrences and all other information that could indicate mineral potential within the BSWI Planning Area. Much of the data used was the result of a mineral assessment of the Aniak Mining District made by the BLM from 2003 to 2006. This district makes up the core of the planning area. Additional field investigations were done in 2008 to assess those portions of the planning area not included in the original mineral assessment.
The evaluation of mineral potential focused on individual mineral occurrences and then on data sets that can be used to further indicate future mineral resource development. Each section of land in the Public Land Survey System within the planning area was given a numerical score based on the sum of various attributes associated with mineral development potential. The mineral potential score is composed of the number and quality of mineral occurrences located within the section and the intersection of areas designated as being significant to mineral potential.
As a result of this study, a total of 57 areas within the planning area are considered to have high locatable mineral potential (LMP). There are a number of these high LMP areas that fall within BLM-managed lands and are covered by federal mining claims. These include: 1) Nixon Fork Mine area; 2) Flat-Chicken Mountain area; 3) Ophir Creek drainage (Kilbuck Mountains), and 4) the NYAC (Shamrock Creek) area. Present and future mineral exploration and mining activities in these areas could have impacts on BLM-managed lands extending outside the mining claim boundaries. Though located on Native patented lands, the access routes to the Donlin deposit will likely cross and have possible impacts on BLM-managed lands.