what are tailings in mining

Tailings are the waste materials left over after the valuable fraction of an ore is separated from the uneconomic fraction during the mining process. They consist of ground rock, water, and trace quantities of metals and chemicals. Tailings are stored in tailings storage facilities (TSFs), which are dynamic structures designed to contain the tailings produced by mining operations. There are different types of TSFs, including surface facilities, in-pit facilities, and dry stack facilities. The design choice is based on factors such as TSF location, site conditions, construction materials, and tailings characteristics. The disposal of tailings is commonly identified as the single most important source of environmental impact for many mining operations. Therefore, modern mines often include the rehabilitation and proper closure of tailings areas in their costs and activities.