Run-of-mine heap leaching selected for Rio2's Fenix gold project in Chile
The company said that material for the trial heap was drilled and blasted from areas of the Fenix North, Fenix Central and Fenix South deposits and composited to make a 426 tonne representative sample. The trial was conducted at Rio2's infrastructure site located approximately 20 kilometers from the Fenix gold mine site at an altitude of 3,200 m.
Water used in the trial leaching was industrial water sourced from the Nueva Atacama water retreatment facility located in Copiapo. Rio2 has a water supply agreement with Nueva Atacama for industrial water for its 20,000 tpd mining project.
According to a press-release, cyanide leaching of the material in the trial ROM leach pad took place over 81 days resulting in recoveries of 75.12% for gold and 12.37% for silver. The company said that these results compare favorably with those from the August 2019 PFS which assumed crushing material to a size of 4 inches with recoveries of 75% for gold and 10% for silver.
Additionally, cyanide consumption averaged 0.18 kg/t and lime consumption averaged 2.95 kg/t, while the PFS assumed cyanide consumption of 0.4 kg/t and lime consumption of 4 kg/t. The percolation rate in the trial heap was 2.4 m/day.
The company said that the successful completion of the ROM heap leaching trial is an important milestone for Rio2 as it simplifies the mining and processing components of the Fenix gold mine by eliminating the need for installing a crusher and the subsequent double handling of mined material before its placed on the leach pad. The resultant reduction of cyanide and lime consumption will also have a positive impact on the mine's operating costs, the company added.
Rio2 noted that it is focused on taking its Fenix gold project in Chile to production in the shortest possible timeframe based on a staged development strategy.