Open pit mine wastewater filtration in the overburden rock debris: case study

Abstract

Discharge of untreated quarry water into natural water reservoirs is unacceptable for environmental reasons. This circumstance is especially relevant for coal mining regions with a high density of mining enterprises. Treatment of quarry waste water at mining enterprises is a necessary process, provided for in the design documentation. It is due to the significant pollution of quarry water by suspended solids, dissolved salts and organic substances. In addition to expensive sorbents (e.g. zeolite), overburden rocks, confined to the mined area of coal deposit, are used for construction of filtering dams. They are used to construct treatment facilities designed for the entire lifetime of the mining enterprise. Thus, their permeability and purification capacity should be maintained for decades. The movement of filtered water in such massifs is subject to the known laws of filtration. Filtering dams should provide both a free movement of water and the required level of its purification. This is achieved by selecting the appropriate geometry of filter dams (their sizes, base slopes) and the choice of overburden capable of providing the required level of purification in a long and qualitative term. The article presents the results of studies of the geometry of the filtering massif and the methodology of selection of overburden used for the construction of filtering dams.