Improving methods for gold recovery in artisanal and small-scale mining without the use of mercury in Ecuador

Despite the ineffectiveness and the environmental issues associated with the use of mercury for gold recovery, amalgamation is widely applied in Ecuador, especially in artisanal and small-scale mining operations. This paper compiles research done during 2014 by the National Research Institute in Geology, Mining and Metallurgy, through the project Improvement of the Working Conditions of Small-Scale and Artisanal Mining. Research efforts were directed to minimize the use of mercury for gold recovery, and to develop alternative methods to recover precious metals and base-metal concentrates without the use of the amalgamation process. Experimental results demonstrated that gold recovery using traditional gravity concentration and amalgamation was as low as 40%. Proposed improvements in the recovery process excludes the use of Hg, incorporates better materials for the primary gravity concentration, and includes the use of a shaking table. As a result, Au recovery may increase to about 90% and more.