Sustainable high-intensity backfill coal mining method: feasibility assessment for ecologically fragile areas of Western China

Abstract

ABSTRACT High-yield coal mining and ecological environment protection are the main aspects of the sustainable development of ecologically fragile mining areas in Western China. This paper briefly describes the development and current situation of solid filling coal mining in China, puts forward a green and sustainable filling coal mining method providing a maximum annual treatment capacity of waste gangue of 2 4 million tons, and analyzes the mechanical compaction properties of solid waste gangue, eolian sand, and loess in these areas. Taking a Coal Mine in Inner Mongolia, China, as an example, the effects of three key indices, namely mining height, face width, and backfill materials’ compaction ratio (BMCR) on the subsidence, horizontal deformation, horizontal movement, inclined deformation, and curvature of Quaternary aquiclude are studied. At a mining height of 3 m and BMCR = 80%, the maximum aquifer subsidence is below 168 mm. Based on the surface vegetation growth capacity analysis, the design principle of controlling the SBM key parameters by the ecological water level threshold is substantiated. The results show that the mining height and the BCMR of goaf are the key control indices affecting the stability of Quaternary aquifers, the evolution of ecological water level, and the production of surface vegetation. Combining the underground intelligent dry coal preparation and in-situ filling coal mining technology with a reasonable adjustment of the above parameters, the ecological environment protection can be realized for the whole life cycle of local coal seam mining in the areas under study.