We use a tailings thickening step in the downstream process from the concentrator, which allows clear water flow to be directly used in the process and reduces tailings water. At Peña Colorada in Mexico, the tailings are in the range of 40 to 45% solids. We’re now taking thickening one step further, installing a paste plant where tailings will be further thickened to 68% solids, reaching up to 70% and the overflow reused directly in the process.
To avoid polluting the surface water runoff we also segregate it from process water, and we divert it for the same reason. This reduces the load and size of the clarification systems for water reuse, and also reduces environmental impacts.
Since 2018, all new capital projects employing wet concentration considered in ArcelorMittal Mines must include dry tailings solutions. View details about how we ensure the safety of tailings storage facilities.
Photos below of our tailings thickening plant at Peña Colorada in Mexico.