MINE WASTE: SOURCES, PROBLEMS AND MITIGATIONS.

Abstract

Mine wastes are unwanted, currently uneconomic, solid and liquid materials found at or near mine sites. Mining waste originates from the processes of excavation, dressing and further physical and chemical processing of wide range of metalliferous and non-metalliferous minerals by opencast and deep shaft methods. It comprises overburden, run-of-mine rock as well as discard, slurry and tailings from the preparation/beneficiation or extraction plants. The major problem is Acid Mine Drainage (AMD) which can lead to poor water quality, soil contamination and air pollution when the wastes are dry in the summers. The conventional method of treatment has been through methods such as lime neutralization, ion exchange, calcium silicate neutralization and carbonate neutralization; but the best way to treat AMD is prevention which can be done by using proper reclamation methods, which prevents air and/or water from reaching the pyritic materials. Generally, conventional technologies for remediation of mine tailings have focused on physical and chemical stabilization. Physical stabilization entails covering mine waste with an innocuous material, waste rock from mining operations, gravel, topsoil from an adjacent site, or a clay capping, to reduce wind and water erosion. Presently, alternative methods for the remediation of mine waste have been prescribed and adopted in various countries. Such methods includes bioremediations and phytoremediations.