Coupling of underground coal mining and mine reclamation for farmland protection and sustainable mining

Mining-induced subsidence inevitably caused damage to farmland and created newborn ponding in mining areas with high groundwater tables. However, traditional mining and reclamation (TMR) is characterized by low reclamation and long-term farmland abandonment. Here, two critical width models of the skip-panel and the back-panel were proposed to protect farmland and increase the reclamation rate. Secondly, concurrent mining and reclamation (CMR) and TMR were simulated according to mining-induced subsidence and farmland damage patterns. The advantages of CMR were discussed in comparison with TMR. The results show that: 1) The layout of underground mining was optimized to successfully achieve farmland protection; 2) The overall and staged layouts of mine reclamation were optimized by incorporating final settlement and earthwork balance; 3) The proposed earthwork allocation allowed lower pre-filling heights and rapid reclamation; 4) CMR can prolong the life of farmland by 12.5 years and increase reclamation rate and farmland area by 50.31% and 869.40 ha; 5) CMR has high costs in the short term, but has good social and ecological benefits in the long term. In terms of policy, we recommend the government increase the reclamation rate index and encourage enterprises to adopt CMR. CMR is the realistic need for sustainable mining and will gradually become a new hotspot for scientific mining. This study can provide a reference for sustainable mining and land use management in coal resource-based cities with high groundwater tables.