Spatial distribution characteristics of mine water quality in coal mining areas of china and technological approaches for mine water treatment

Mine water is an important unconventional water resource. The water inflow of coal mines in China is huge. The treatment of different types of mine water is a key scientific issue for both the government and coal mining enterprises. Based on the investigation and statistical analysis of water chemistry data from 314 coal mines, the spatial distribution characteristics and causal mechanisms of mine water quality were elucidated. Mine water quality is mainly characterized by high TDS, high suspended solids, high sulfate, and high Na⁺, while acidic mine water and heavy metals are mainly concentrated in some mining areas such as Yunnan and Guizhou; The causes of water quality are closely related to the geographical characteristics of coal mining areas, such as arid and semi-arid climate conditions, water quality of water filled underground aquifers, sulfur content of coal seams, rock lithology, microbial activity, magmatic activity, and other factors. Mining activities have a significant impact on the formation and evolution of mine water quality. The hydrochemical types of mine water across the country are primarily SO₄−Na, SO₄−Ca·Mg, SO₄−Na·Ca, HCO₃−Na, and HCO₃−Ca·Mg. Based on the national mine water quality characteristic, the study discusses existing surface treatment technologies for mine water, their limitations, and current underground treatment methods. A novel mine water natural remediation technology for abandoned mining spaces is proposed, focusing on the “block, reduce, and protect” approach to pollution control. The technology aims to achieve low-cost underground treatment and reuse of mine water through process reduction. The study further constructs a technical framework based on key scientific issues, including the selection of mining void locations, calculation of storage space in the mining area, safety evaluation of water storage, and evaluation of the reduction and remediation effects. A multi-field evolution model, incorporating hydrodynamics, water chemistry, and microbial dynamics, is established to support the remediation process.The feasibility of this mine water remediation technology is verified based on chemical compositions of water and microbial community evolution in real coal mine examples. The results show that the proposed technology can effectively reduce treatment costs, promote coordinated coal-water sustainable development, and enable the remediation and resource utilization of mine water, with significant application potential.