Cerro Santa Rosa tailings dam: Storage capacity increased using a unique mechanically stabilized earth design

摘要

Triton Minera S.A. (TMSA) owns and operates Mina El Limon located in northwestern Nicaragua, approximately 100km northwest (140km by road) of Managua, Nicaragua's capital city, and approximately 45 km northeast of Leon. El Limon is an underground gold mine and mill that processes nominally 1,000 tonnes per day of ore through a carbon in pulp recovery plant. Cyanide tailings are deposited in the Cerro Santa Rosa tailings disposal facility; an unlined valley-fill impoundment confined by an earthfill tailings dam. Capacity of the Cerro Santa Rosa tailings impoundment was increased by utilizing a reinforced earth crest raise combined with a rock fill buttress and downstream shell. Plagued by diminishing storage capacity and a short construction season, an innovative application allowed the operators to raise the dam quickly while maintaining an adequate factor-of-safety against slope instability, in a high seismic region. The unique application accommodated a near vertical upstream dam slope, which consequently reduced the fill required to raise the dam, which was historically constructed by conventional downstream methods. Considerable cost savings were realized by the dam owner as a result of a reduced fill volumes and an expedited construction schedule.