Tailing impoundment permitting, design, construction, and operation in an arctic environment

摘要

The Fort Knox mill, located 26 miles northeast of Fairbanks, Alaska stores an average of 41,200 tons of tailings per day in a valley fill impoundment with a capacity of approximately 200 million tons. Design, operation, and construction of the embankment incorporate considerations for arctic conditions. Unsuitable material must be removed from beneath the embankment random fill and engineered zones and grouting prevents erosion of underlying material. A comprehensive construction quality assurance program assures embankment construction meets the design specifications. The seepage collection system and interceptor wells assure the impoundment operates as a zero discharge facility. Tailings deposition methods maximize tailing density and minimize ice formation within the tailing mass. A detailed water balance is utilized to predict makeup water needs and assist in assuring emergency storage capacity requirements are maintained. Mitigation measures have been implemented to offset the acres of wetlands impacted by the tailing impoundment construction and operation.