City-scale dynamic mining zoning for source-based damage reduction and efficient coal resource utilization in high-groundwater-table coal–farmland overlapped areas

Abstract

In high-groundwater-table coal–farmland overlapped areas, the superposition of temporal groundwater-level fluctuations and mining-induced subsidence exposes permanent basic farmland to long-term dynamic risks. However, existing mining spatially partitioned subsidence control technology generally adopts static groundwater levels as the design baseline, resulting in conservative risk assessment and constrained resource utilization efficiency. To address this issue, a city-scale mining suitability zoning method incorporating groundwater dynamics was proposed in this study. Taking Yongcheng City, China, as a case study, groundwater monitoring data from 2019 to 2024 were used, and a Long Short-Term Memory (LSTM) model was employed to achieve quarterly dynamic updating of groundwater levels. Furthermore, a dynamic groundwater threshold was established under the dual constraints of crop yield reduction and soil salinization, and was coupled with subsidence responses under different mining methods to develop a dynamic zoning determination system. The results indicate that the study area exhibits a city-scale spatial pattern characterized by restricted mining in the sensitive western area, conditionally suitable mining in the central area, and natural mining in the eastern area. Compared with conventional mining design, the proposed dynamic subsidence-control design increases the suitable mining area by 74.24% relative to the conventional design, while maintaining the productive function of permanent basic farmland. At the pre-mining planning stage, 103.65 km² of stably releasable overlying coal resource space and 299.74 km² of conditionally releasable space requiring dynamic regulation can be identified within the coal–farmland overlapped area. This study provides a city-scale decision-making pathway for alleviating the conflict between coal resource extraction and permanent basic farmland protection in high-groundwater-table regions and for achieving efficient utilization of underlying coal resources.