Anglo American’s Los Bronces copper mine in Chile has an ambitious plan to recycle more water by sucking it from the bottom of a tailings dam. More than 200 million m3 of waste water are retained in the fine tailings of Las Tórtolas dam, which is currently up to 100 m deep. Retained water will increase to more than 750 million m3 during the life of the mine. Water retention in the tailings is the biggest part of water consumption at Los Bronces and many other mines. The proposed water-recovery scheme aims to increase water re-use efficiency by extracting some of this water and pumping it back to the Los Bronces processing plant at Las Tórtolas.

The plan is for 29 mm horizontal wells to be drilled through the permeable weathered bedrock along the bottom of the dam and then lined with a 19 mm perforated steel pipe into which water will drain. It could improve Los Bronces’ water efficiency by reducing water consumption by up to 20%, contributing to meeting our sustainability targets. “If this works, it will be a revolution in mining that helps to solve a lot of water challenges,” says Christian Cintolesi, Water Lead for the Americas. A trial well is scheduled for the first quarter of 2020, with monitoring and evaluation of results due by mid-2020. Current estimates put the overall project cost at $30-$75 million.