QUANTITATIVE EVALUATION OF ECOLOGICAL ENVIRONMENTAL DAMAGE CAUSED BY COAL MINING IN SHENFU AREA OF ORDOS BASIN

Yushenfu mining area is located in the transitional zone between the Mu Us Desert and the hilly and gully region of the Chinese Loess Plateau. The earth's surface of this area is covered by thick and unconsolidated sand and soil along with arid weather and sparse vegetation throughout the year. The coal seam in this mining area is characterized by shallow burial, large mining thickness and thin bedrock which often leads to a series of ecological environmental damages when coal mining. By analyzing mining subsidence, groundwater damage and formation mechanism of ecological environmental damage in Yushenfu mining area, it is believed that mining subsidence is the most important and fundamental damage which is formed by joint influence and interaction of coal occurrence conditions and coal mining design conditions. Groundwater damage and ecological environmental damage are the chain reaction and derivative damage of mining subsidence. The impact indexes of mining subsidence are screened, and five indicators are selected to represent the mining subsidence subsystem, including perturbation coefficient, width/depth ratio, synthetical Protodyakonov coefficient of overlying rocks, sinking coefficient and depth/thickness ratio. Based on the single factor and comprehensive evaluation of the ecological environmental damage of 12 evaluation sample mines in Yushenfu mining area, it is considered that the mining subsidence damage in this area is serious as a whole with spatial distribution patterns, and the quality grade of ecological environment conditions is by and large between good and general. Effective control and treatment of mining subsidence damage will play a decisive role in the control and reduction of ecological environmental damage in the whole Yushenfu mining area.