Los Andes Copper Ltd has announced that as a part of the ongoing Pre-Feasibility Study (PFS) at the Vizcachitas Project in Chile, it has received improved flotation rougher recoveries resulting from further metallurgical testwork. Through optimising the rougher flotation conditions, the company will be able to increase copper and molybdenum recoveries.

During 2019, as part of initial testwork for the PFS, a sample from previous testwork that represents the upper zone of the orebody was sent to SGS Minerals facilities for a rougher flotation assessment. The results of this assessment show that copper and molybdenum rougher recoveries, as compared to the 2019 Preliminary Economic Assessment (PEA) formula, were improved by 3% and 6% respectively. This improvement was achieved by refining the flotation formula: decreasing pH, lowering the solids percentage of the slurry and adding a stronger frother.

The ongoing PFS metallurgical testwork in 2020 has confirmed these improvements. A new composite sample from the first 12 years of the mine plan was tested using both the PEA and PFS flotation formulas. The PFS formula shows an improved rougher recovery of 2.8% for copper and 7.8% for molybdenum over the PEA formulas.

Fernando Porcile, Executive Chairman of Los Andes, commented: “I am pleased that the improved formula results from the current PFS testwork further enhance the project economics of an already robust project. The ongoing Pre-Feasibility Study for the Vizcachitas Project has confirmed the use of HPGR technology and validated the use of dry-stacked tailings. These technologies put the Vizcachitas Project at the forefront of the environmentally responsible practices being adopted for the future of sustainable mining globally.” In terms of this specific referenced equipment, the company is currently factoring in 18 Metso Outotec e500 500 m3 TankCell rougher flotation cells (2 x 9) at the project along with two Metso Outotec HRC2600 HPGRs.

The Vizcachitas approach to tailings dewatering involves the classification of rougher tailings by hydrocyclones. The coarse fraction or cyclone underflow (+400#) will be fed to belt filters. The fine fraction, comprised of the cyclone underflow (-400#) and the scavenger tailings will be fed to pressure filters. Vizcachitas tailings amenability to be filtered has been confirmed over the development of the project.