Replacing mercury use and improving gold recovery in artisanal operations

This study aims to improve a process to recover gold in artisanal mining operations by treating a gravity concentrate with cyanide in a closed circuit in a ball mill, trapping gold particles in a capsule of activated carbon in the mill. The main innovation of this process is the use of the activated carbon inside the mill, with no need to remove the balls. Cyanide is safely degraded when the process is complete, with no residual damage to the environment, when the process is carefully applied. Preliminary tests in the Amazon have shown that gold recovery may increase up to 2 times compared to the use of copper plates, even though the process has not been optimized yet. This project involves tests to be conducted at UBC mineral processing lab and in the Amazon region, testing adjustments in the process. It requires lots of mass balance calculations to compare the efficiency of the process when using different levels of reagents, cyanide, charcoal, the mill operation and grinding time.

Faculty Supervisor:

Dr. Marcello Mariz da Veiga


Rodolfo Neiva de Sousa


Earthtone Environmental R&D Inc.




Mining and quarrying


University of British Columbia



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