Tailings

Definition

The waste material separated out during the processing of mineral ores (EPA 2000). Tailings are found as impoundments, piles, or other accumulations in proximity to mills or other processing sites. Processing sites may be near the location where ore is extracted or a short distance away from the mine location (Wills and Napier-Munn 2006).

Characteristics

Commonly, extracted ore is crushed until most of the ore is reduced to particles ranging from sand to silt size (Fig. 1). This process, sometimes referred to as comminution, creates a size range that facilitates separation of the mineral material from the ore by either a physical or chemical process (Wills and Napier-Munn 2006). Roasting, floatation, or centrifuge separation are common physical processes (Wills and Napier-Munn 2006). Chemical processes can involve creating amalgamations or precipitates to more easily separate the ore mineral from the less reactive host rock material. Chemical extraction of gold using...