Integrated Water Management — Assignments of Water Management in Mining Regions

Abstract

The aim of this paper is to describe the implementation of integrated water management projects for mine closure in Germany and Chile, drawing on the experience of G.U.B. Ingenieur AG and BioPlanta GmbH. Integrated water management means the planning, regulation and management of water use throughout the mine life cycle, starting with the draw-down of groundwater level before exploitation, through on-going water drainage due to the cleaning of process water and other waste water, and the management of groundwater recharge following the end of exploitation. Integrated water management systems can make substantial contributions to the non-aggressive and sustainable use of water, and contribute to environmental protection. In terms of water management, we describe the planning and management of the restoration of groundwater levels in areas mined extensively for brown coal mining (Germany and Mongolia). This includes addressing protection of water quality, i.e. the risk of acid mine drainage (AMD). A prerequisite was the development and utilization of complex models to characterize hydraulic properties and potential mass transport. With regards to the treatment of process water in the mining industry, passive biological water treatment technologies are suitable for applications where, (a) water treatment is required for decades, and conventional treatment plants are economically unsuited for long-term operation, (b) water flow rates and pollutant concentrations are variable, (c) treatment of complex mixtures of contaminants (inorganic and organic) is required, and (d) pollution point sources are diffuse. Here we describe the treatment of sulphate- polluted process water from a copper mine in Chile using passive biological systems. In this case the polluted process water was collected in a basin and discharged to a plantation of trees. Investigations are at the technical scale (Germany) and pilot scale (Chile), with the objective of fulfilling the irrigation quality standard enforced in Chile. Passive treatment of seepage from uranium mines in Germany involved the separation of uranium and arsenic using biological processes. This approach involved a combination of anaerobic and aerobic processes within one system for the efficient treatment of the mine water. After treatment of the seepage, it is discharged in a nearby stream. The concept for the Orcopampa Province in Peru addressed municipal waste water from the settlement Orcopampa, and mining industry water (Buenaventura). The water streams from the two sources were combined in order to improve efficiency of a biological treatment system that relies on the synergism between both, i.e. the organic carbon source and nutrients in the municipal waste water supports microbiological processes that in turn are responsible for the treatment of the mining industry water.