Spatial-temporal characteristics of land degradation and its influencingfactors in coal mine areas in Western China

Coal mining seriously damages the ecological environment, and diagnosis of land degradation is an important prerequisite for building green mines. In order to explore the impact of coal mining on land degradation in coal mine areas (CMAs) in Western China, twelve typical CMAs belonging to Northern Steppe Region (NSR), Loess Plateau Region (LPR), Southwest Mountain and Hilly Region (SMHR) and Northwest Arid Region (NAR) are selected as research objects. Indicators include land damage, land use type, vegetation coverage, desertification or rocky desertification, soil erosion. The weights of different regions were determined according to the specificity of the ecological environment. Finally, the land degradation in CMAs in Western China was divided into 5 levels: severe degradation, mild degradation, stable area, mild improvement, and severe improvement by using linear regression trend analysis. And land degradation status, the driving influence of coal mining and annual precipitation on land degradation in CMAs in Western China were discussed. The results show that: ①During 2013～2017, the degree of land degradation in the NSR and the SMHR was slightly severe, but the improvement was in good condition. Ecology was stable in the LPR. The improvement trend was obvious in the NAR. ②The “extremely severe damage” area of underground mines accounted for an average of 5.61%, and open-pit mines accounted for an average of 36.44%. Therefore, open-pit mining is more serious than underground mining on surface damage. The “severe degradation” area of open-pit mines accounted for 13.58%, which was larger than 8.27% of underground mines. The “mild degradation” area of underground mines accounted for 30.49% of the area, which was larger than 15.08% of the open-pit mines. Therefore, Open-pit mining has a serious impact on land degradation in the small areas,and underground mining has a slight impact on land degradation in the large areas. ③Land degradation at the mine-scale is mainly driven by precipitation, and the main driving factor of degraded areas at the CMA-scale is the disturbance of artificial mining.