Water Management and Protection in Opencast Mining Regions and Utilization of Mine Water

摘要

Opencast pits are dewatered exclusively through gravity drainage, the predominant technique being the use of dewatering boreholes. Support is basically assured by the material inserted in the excavations (ceramic pipes, cement filter pipes, gravel filters). The perforated and solid-wall pipes used in the boreholes have an internal diameter of 350 mm. There is only limited use of metal piping to support dewatering boreholes and it is confined to those areas of pits that are free from mining activity. The water raised to the surface by means of submersible pumps with submersible motors is directed into a collector (pressure or non-pressure pipeline, drainage ditch) and carried to a groundwater treatment plant or directly to the drainage system or to a user (for example, to a waterworks). Mine water is purified: in artificial lakes; and in mine-water treatment plants. The water is mechanically purified and neutralized through the addition of lime and the precipitation of the iron in the form of iron hydroxide sludge. Approximately 60% of all mine water is purified; 40% of such water is of sufficient quality to be discharged without treatment. The quality characteristics of purified mine water correspond to the figures. Generally speaking, the purified mine water improves the quality of the water in receivers. The amount of mine water used represents 39% of the total. It is supplied in the form of raw water and the receiving Kombinat is responsible for upgrading it for industrial or human consumption (for its own needs or for the supply of drinking water to the public). (ERA citation 13:024077)