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Investigation of the Nixon Fork Area, Kuskokwim River Basin, Alaska.
Work on the copper-gold-silver deposits of the nixon fork area consists of two parts; a metallurgical section and a reconnaissance examination. The metallurgical work was done to develop a method suitable for extraction of gold and copper from the complex silicate ores. Results indicated that additional research is required. Caustic leaching is a potential method for recovery of copper from chrysocolla ores associated with basic minerals; ammonia leaching and flotation methods were ineffective. A high gold recovery is not possible without simultaneous recovery of copper. Gold recovery methods include tabling, corduroy matting, flotation, and barrel amalgamation. Work was done in Juneau with commercially available reagents and equipment. The reconnaissance examination was made to determine the feasibility of additional work by the Bureau in determining the mineral potential of the area. Paleozoic limestone and Cretaceous sandstones have been intruded by quartz monzonite. Copper, gold, and silver mineralization were found in limestone and granite in an area about 1 mile wide and 2 miles long. Mineralization occurred chiefly as copper silicate but minor amounts of copper sulfides were found. Gold and silver were associated with copper mineralization; minor amounts of bismuth were found. Mineralization was still present at approximately 600 feet below the surface in the deepest underground workings.
Page last reviewed: September 24, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division