Tailings thickening challenges at Kamoa Copper

Kamoa Copper Mine is already the world’s third-largest copper producer, and it has the ability to grow further. Start-up of the Phase 3 Kamoa concentrator has thrown up some interesting issues with the flocculation and thickening of the tailings, and these are discussed, along with the corrective actions taken. The plant was suffering from almost continuous ‘sliming’, where the bed rises within the thickener, eventually overflowing solids, compromising the process water for the whole flotation circuit. The case highlights several problems commonly encountered with thickeners when starting-up, including product selection issues and initial operational difficulties. It shows how working through the issues systematically and applying experience from other operations helps. Simple static cylinder testing has been used extensively and becomes a valuable troubleshooting tool. It is a technique that, with a little training, most metallurgists can use.