154 / 2022-02-11 10:19:24

Technique of Concurrent Mining and Reclamation in Multiple-seams Repeated Mining with High Underground Water Table

mining subsidence, multiple coal seams, repeated mining, land reclamation, concurrent mining and reclamation

Environmental Science and Engineering > 3. Land Reclamation and Ecology Rehabilitation

In China's coal-cropland overlapping area, the reduction of arable land caused by coal mining collapse is a direct threat to national food security. To maximize the protection of arable land resources, the whole mining life cycle of the Concurrent Mining and Reclamation system based on pre-mining analysis-mining dynamic damage prediction- reclamation simulation has been formed basically, which gradually becomes an inevitable trend to realize the sustainable utilization and development of land resources. However, with the exploitation of deep coal resources, a more complex mining environment and drastic mining disturbance lead to more significant uncertainty of surface subsidence, and the repetitive mining-side rehabilitation of deep coal seam clusters urgently needs theoretical enhancement and technical perfection. This paper summarizes the development history of land reclamation methods in mining subsidence areas and introduces the concept, design, and principles of Concurrent Mining and Reclamation. Taking the repeated mining of 11-2 coal seam and 13-1 coal seam of Guqiao coal mine in Huainan mining area as the engineering background, the improved normalized difference water index (mNDWI) and maximum inter-class variance (OTSU) image segmentation algorithm were adopted to analyze the spatial distribution and expansion of mining subsidence wetlands from 2008 to 2020 based on Landsat remote sensing images. Combined with the mining plan, the Probability Integral Method was applied to invert the repeated mining surface movement to reveal the time-series influence of mining subsidence on surface water accumulation. Then, by using the numerical simulation software of FLAC(3D) the surface deformation law caused by different mining plans of multiple coal seams, aiming to effectively control the overlying strata movement and surface subsidence through rationalizing the preferred mining solution, and actively selecting the land use mode and treatment scheme according to the local conditions. Meanwhile, the feedback of land use planning was used to guide the design of the mining scheme, to realize the harmony and unity of coal mining and land use during the whole mining life cycle.