| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4457280 | Journal of Geochemical Exploration | 2014 | 9 Pages |
•We studied effects of hard coal waste dumps on the surrounding environment•We identified mineralogical composition of waste rocks located in study area•Mineralogical composition of samples changes with the depth of the dump profile•We analyzed chemical composition of water extracts from studied solid samples•Mining water affects chemical composition of surface water at the study area
Numerous hard coal exploitation centers were operated in the Lower Silesia Coal Basin (south-western Poland) until the end of the XXth century. As a result of this industrial activity large amounts of mining wastes were deposited in the vicinity of the coal mines. This study focuses on potential environmental effects of hard-coal waste dumps on the surrounding environment, especially on water. We sampled waste rock along the 10 meters depth profile from one of the dumps located in the study area. Mineralogical composition of this material is heterogeneous and varies at different depths of the profile. Upper part of the dump is mostly composed of quartz, muscovite, kaolinite and Fe oxyhydroxides. Deeper part of the dump consists of waste rocks composed mostly of mullite, gypsum, jarosite and quartz. Solid samples were subsequently subjected to a one step extraction using distilled water in order to show a potential leachability of inorganic contaminants from wastes. Results of the leaching experiment show that chemical composition of effluents clearly depends on the mineral composition of wastes from different parts of the dump. Sulfates and Ca2 + concentrations are higher for the water extracts for samples in the bottom of profile (up to 40000 mg L− 1 and 15000 mg L− 1 respectively), whereas for the samples from upper part of the dump SO42 − and Ca2 + concentrations are much lower (up to 1000 mg L− 1 and 160 mg L− 1 respectively). Leaching test revealed also that considerable concentrations of some metallic elements are mobilisable from studied waste material (e.g., Zn, Pb, Cu). Chemical composition of water samples (mine water outflows, groundwater) analysed in this study indicate negative environmental impact of the studied waste dump. These waters are generally characterized by high concentration of total dissolved solids with SO42 − being the dominant constituent, low pH and important amounts of some metallic elements (e.g., Zn up to 6 mg L− 1).On the basis of mineralogical analyses coupled with leaching experiments and chemical analyses of waters our study clearly indicated that mining wastes affect quality of surface and ground waters in the studied site.
