Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

Coal fields in South Korea have been grouped into seventeen mainly based on geological age, structure and geography, and thirteen of them have been developed. In order to elucidate the physico-chemical characteristics of mine drainage from each coal field and the intrinsic reasons of differences among them, if any, sampling and analysis of waters from 61 mines in eight coal fields have been carried out. The coal seams of the Chungnam coal field from the Daedong system (Mesozoic era) which are mostly located between breccia and coarse sandstone formations contain relatively smaller amount of sulfides than coal-bearing formations of the Pyungan system (Proterozoic era). Mine drainage waters from the Daedong system, Chungnam coal fields mostly showed lower heavy metal and sulfate concentrations than those from the Pyungan system. Among the coal fields of the Pyungan system, differences can also be found in metal and sulfate concentrations. The Kangneung and Samchuck coal fields, in which coal seams are located between mostly shale formations, show higher metal and sulfate concentrations than the other coal fields. The Boeun and Honam coal fields show the lowest metal and sulfate concentrations among the coal fields of the Pyungan system, which may be due to the metamorphic rocks lying beneath the formations of bearing coal seams. The metamorphic rocks contain less sulfides and higher permeable fractures comparing to formations of other coal fields of Pyungan system.