Study On Site Classification And Evaluation Of Dump In Wuhai Coal Mining Area

Against the backdrop of the current ecological civilization construction,ecological protection and restoration of mining areas has emerged as a hot topic and focus.Taking Wuhai coal mining area as the research object,this study identifies the dominant factors for classifying the site types through correlation analysis and principal component analysis of the site factors of the waste dump sites,and employs cluster analysis to classify the site types of coal mining sites and analyze the characteristics of each site type.The evaluation indexes are selected by considering the environmental factors in the study area,so as to establish the index system for evaluating the site quality.The index weights are determined by the factor analysis method for the quality evaluation of site types.The research results indicate that:(1)The dominant factors screened for the waste dump sites in the coal mining area are the three site factors of micro topography,earthing thickness and soil texture;with this basis,the 23 typical sample sites are classified into 1 site type district,4 site type subgroups,and 10 site types.(2)Through the analysis of the characteristics of different site types of the waste dump sites,the following results are obtained: regarding the overall consideration of the waste dump sites in Wuhai mining area,the waste dump area is large,the platform site type is flat,with thin earthing thickness and high gravel content of 15.17%;the site slopes range from 28° to 52°,with large gradients,and the thickness of the earthing is mostly thin;the gravel content is mostly greater than 10%,and excessive thinness of the earthing exposes the surface,while high gravel content leads to a decrease in water and fertility retention of the soil,thus limiting plant growth.There are four types of sites for steep slopes with gradients between 25° and 35°,two types of sites for sharp slopes with gradients between 35° and 45°,and three types of sites for dangerous slopes with gradients between 45° and 55°.(3)The general site type quality of the Wuhai mining waste dump site is relatively inferior.The site quality among the 10 site types obtained through the site type classification of typical sample sites can be classified into 4 levels: the composite score of favorable site conditions is >0.4,the composite score of average site conditions is 0.4～0,the composite score of unfavorable site conditions is 0～(-0.6),and the composite score of extremely inferior site conditions is <-0.6.