Recently, the National Development and Reform Commission, the Ministry of Water Resources, the Ministry of Natural Resources, the Ministry of Ecological Environment, the Ministry of Emergency Management, the State Administration for Market Regulation, the National Energy Administration, and the State Mine Safety Administration jointly issued the Guiding Opinions on Strengthening Mine Water Protection and Utilization (Reform and Environmental Protection [2024] No. 226, hereinafter referred to as "the Guiding Opinions"). The document systematically plans for strengthening mine water source protection, classified treatment, and comprehensive utilization in the new development stage. It has important significance for strengthening mine water protection and utilization and supporting high-quality development in the energy and resources sector.

I. Fully recognize the important significance of promoting the protection and utilization of mine water

(1) It is an important way to promote the green transformation of the coal industry. Mine water is an important unconventional water source, and the strengthening of mine water classification, graded treatment and rational reuse can reduce the dependence on other water sources and reduce the pollution to the ecological environment, and promote the coal industry toward green, low-carbon and sustainable development, improve the competitiveness and sustainable development capabilities of enterprises, contribute to the high-quality development of the regional economy.

(2) It is an effective means to fully optimize the water resources allocation pattern. Water resources are a basic element for economic and social development. China's per capita freshwater resources are far lower than the global average. The contradiction between water supply and demand has become a significant bottleneck restricting the high-quality development in the region. Integrating mine water into the comprehensive water resource management system provides a diversified supplement for the allocation of water resources and improves the utilization rate of mine water, which helps alleviate the contradiction between coal and water as well as the regional imbalance between water supply and demand.

(3) It is an inevitable choice for cooperative resource development and ecological and environmental protection. Groundwater is an active factor in the water cycle. The centralized development of coal bases leads to groundwater damage, which emerges as mine water and causes water resources, water environment, and compound water ecological problems, increasing the risk of ecological environmental degradation. Deepening the protection and utilization of mine water sources can fully play the resource, ecological, and environmental attribute functions of mine water, which is helpful to realize the organic unity of coal and water resource co-extraction and ecological environmental protection. Mine water protection can effectively reduce geological environmental problems such as ground subsidence, stratum deformation, and soil erosion caused by groundwater level decline, and support the carrying capacity of the stable mining area's geological environment.

Integrated promotion of mine water protection and utilization

The "guiding opinions" establishes a framework system for protecting and utilizing mine water, which includes spatial dimension, time dimension and process dimension, and takes full consideration of multi-processes including mine water source control, process treatment and intensive utilization. It is helpful in resolving the conflict between mine safety production, water supply assurance and ecological environment protection, and achieving the win-win goal between coal resources and water resources.

(I) Source-control to protect groundwater resources. The Guideline stresses that coal production should be within the carrying capacity of the water environment. The regional master planning and environmental impact assessment for the mining area should clearly identify the aquifers that need to be protected in the area. In designing new coal mines, water resource protection measures should be chosen in accordance with local conditions based on mining conditions. In producing and to-be-produced coal mines, areas that may cause serious damage to groundwater resources shall not be mined without authorization. Aiming at the actual situation that the main aquifer type in different mining areas varies greatly, the Guideline defines that in North China, where the mining area is affected by the bottom aquifer, it is suggested to adopt technologies such as advanced regional governance, structural zone local grouting reinforcement and sealing, and preventing the bottom confined water from entering the mine; in Northwest and Northeast, where the mining area is mainly affected by the roof sandstone aquifer, it is recommended to adopt technologies such as lateral aquifer curtain cutoff, permeable skylights and isolated weak water zones to reduce the loss of groundwater in the main aquifers; in Southwest karst aquifer-affected mining areas, it is recommended to adopt comprehensive detection and karst channel local grouting curtain, land sinkhole backfilling and other measures to change the replenishing conditions of the karst system in the mining area and reduce direct replenishment of the karst water system by atmospheric precipitation.

(2) Classified treatment to improve the efficiency of mine water treatment. The "Guiding Opinions" emphasize the scientific and precise implementation of harmless, resource-based and efficient treatment of mine water classification, quality classification, and classification. On the basis of meeting the goals of resource utilization and ecological utilization, it takes into account the reasonable feasibility of economy and technology. The "Guiding Opinions" cover specific treatment measures for mine water containing suspended solids, high salinity, acidity and special components, focusing on the treatment of mine water with high salinity, acidity and special components, and encouraging the use of seawater desalination technology, Thermal desalination, underground pretreatment-deep surface treatment processes, efficient defluoridation and other technologies have reduced the cost of large-scale treatment of highly suspended mine water to less than 1.3-2.0 yuan per cubic meter. The desalination treatment cost of highly mineralized mine water is less than 13 yuan per cubic meter, ensuring the economy of protection and utilization, and encouraging Kuangqu enterprises to increase their enthusiasm for mine water treatment. The "Guiding Opinions" recommend using the energy advantages of Kuangqu to help green and energy-saving treatment of mine water, and developing and using renewable energy such as geothermal energy and solar energy in mine water treatment.

(III) Comprehensive Utilization, Improving Mine Water Utilization Rate. The Guiding Opinions emphasize that we should improve mine water utilization and efficiency utilization rate and strive to lift the rate of mine water utilization in the Yellow River Basin to 68% before 2025 by incorporating mine water into regional water resources planning and the unified deployment of water resources. We should accelerate construction of mine water transmission pipes, scientifically transfer water, and optimize the deployment of water resources for daily life, production, and ecological conservation. After routine treatment, used in coal preparation plants, gangue waste rock piles, ground de-dusting and also coal washing and coal preparation; the water that meets greening water standards can be used as water for greening. After deep treatment, mine water can be utilized as production water in such industries as coal chemical engineering and as recycling cooling water for electric power, steel industries, etc. Coal mining areas that provide suitable conditions can transfer mine water that reaches the usage water quality standards to industrial zones, enterprises, or neighboring towns and cities as production water and general municipal water. In terms of ecological and agricultural water use, in areas that overly pump groundwater, upon complying with laws and regulations and conducting scientific and reasonable assessments of mine safety impacts and the water environment, we should explore the feasibility of recharging or storing groundwater after deep treatment and quality testing of the mine water. In areas of the Yellow River Basin with severe water shortages, we encourage using mine water that has been treated to reach standards in pasturing replacing groundwater and surface water; under the premise of satisfying the ecological and environmental protection requirements, mine water that has been treated to reach standards can be used for ecological water consumption in the river basin.

Third, strengthen the system and mechanism to enhance policy safeguards

Reinforce supervisory assessment to ensure safe handling and utilization of mine water. The Guiding Opinions propose that mine water should be incorporated into the unified allocation of water resources, the mine water monitoring system should be improved, and assessment targets and requirements for the protection and utilization of mine water should be clarified. Strengthen the supervision of mine water treatment to meet emission standards, carry out dynamic monitoring of multiple indicators for long time series, and establish a risk prevention and warning system for the whole process of mine water protection, treatment, and utilization.

(2) Advance the reform of water resources tax and improve incentive mechanisms for mine water utilization. The Guiding Opinions define innovation mechanisms for market utilization of mine water, such as advancing mine water use right trading and advancing water resources tax reform. Improve the central and local fiscal support and guarantee mechanism, broaden investment and financing channels, and play an important guiding role in increasing mine water treatment and utilization market vitality, regulating market behaviors and promoting sound development of the industry.

(3) Promote in-depth integration of production, education, research, and application, and develop green water conservation and water use. The Guideline proposes to deploy relevant scientific and technological innovation tasks around key technological breakthroughs to promote scientific and technological innovation breakthroughs. It encourages enterprises to carry out research on new technologies related to the protection and utilization of mine water, and to strengthen the application of relevant innovative technologies in mine water protection and utilization projects. It also encourages breakthroughs in the manufacturing of key core equipment, and the promotion of the transformation of mine water protection, treatment, and utilization towards scientization, precision, and intelligence.

The "Guiding Opinions" adhere to the combination of goal orientation and problem orientation, clarify important measures that need to be taken for water-retaining mining in different mine field types, and put forward specific requirements for implementing intelligent, green and directional treatment of mine water in all spaces, fields and processes. It points out the application scenarios of mine water in production and living utilization, ecology and agricultural utilization, and also emphasizes key measures such as improving the statistical measurement and assessment system, improving policy standards and tax price mechanisms. Focusing on conceptual innovation on the basis of precise policies will effectively promote the comprehensive and rapid development of mine water protection and utilization in China. It is recommended that relevant mineral-related areas use the "Guiding Opinions" as a blueprint, put the protection and utilization of mine water in a more prominent position, strengthen overall coordination, effectively alleviate the coal-water conflict in Kuangqu, and promote the green transformation and upgrading of the coal mining industry. (Author: Wu Qiang, academician of the Chinese Academy of Engineering)