Research On Dynamic Evaluation System Of High-efficient Utilization Of Water Resources In Large Open-underground Combined Minning Coal Mine Based On LCSA Theory

With its multiple attributes,water resources have always become an indispensable means of production for coal mining.The high efficiency of water use is a crucial factor in promoting a healthy water cycle in the region.Large open-underground combined mining coal mines have diverse water sources and sophisticated water use and drainage structures.The related technical system,process flow,and equipment system of the water resources system have long chains and many links,and the characterization indicators are complex and changeable,which urgently need feedback,adjustment,and optimization.Guiding the use and management of the regional water resource life cycle(water intake,distribution,utilization,drainage,treatment,recycling,or disposal)with a scientific and comprehensive assessment system is of great practical significance.For example,to break through the bottleneck of uncoordinated and insufficient water use efficiency,achieve rational development,optimal allocation,and sustainable and efficient use of water resources.The article takes the large open-underground combined mining area of Antaibao and Anjialing in China Coal Pingshuo Group as an example,explores and analyzes water metabolism and water footprint of the mining area based on studying the relevant theory of the life cycle.Based on the life cycle sustainability theory,integrating the five dimensions of resource consumption,economy,technical performance,social impact,and environmental impact,a total of 19 list factors,a dynamic tracking,and evaluation system for the efficient use of water resources in the life cycle sustainability was established.Through the game theory method,the weight calculated by the Analytic Hierarchy Process and the CRITIC method is optimized to obtain fusion weight,and the CW-VIKOR method is used to interpret the evaluation result and continuous improvement information feedback.The main conclusions of the study are as follows:(1)The results of water metabolism analysis show that from 2015 to 2018,the proportion of freshwater decreased in the water supply in the region,and the use of recycled water gradually increased.However,there is still a large amount of surplus recycled water.Because the water quality cannot meet the high requirements of water users,the scope of reuse is limited,so it cannot efficiently use of water resources.The demand for water in the primary coal industry has declined,the amount of water used by other sources has increased,and the water use structure has changed.The water footprint calculation results show that the regional gray water footprint exceeds 1.3 times the blue water footprint,and the supply chain water footprint exceeds the operating water footprint by 1.4 times.It shows that indirect water consumption other than direct water resource utilization in the region should receive more attention.(2)From the perspective of the life cycle,the environmental impact of the system mainly comes from direct or indirect environmental emissions,including regional drainage,domestic sludge landfill disposal,and water system energy consumption.The environmental impact potential values of GWP,EP,AP,and HTP account for approximately 53%,26%,20%,and 1%,respectively.Among them,the effect of global warming is the most significant,and the potential value of human toxicity is the weakest.The impact of global warming is the most significant,and human toxicity potential is the lowest.The power and energy consumption of the water resource system has the most significant environmental impact,accounting for about 73%,regional drainage accounts for about 26%,and domestic sludge landfill accounts for about 1%.(3)The CW-VIKOR method can coordinate the interrelationships between resource consumption,economy,technical performance,social impact and environmental impact within the system boundary,and finally become an effective means of water resources life cycle sustainability assessment.The credibility of the evaluation results is high and close to the actual situation.It is concluded that during 2015-2018,the life cycle sustainability comprehensive utility values Q_i are 0.983,0.813,0.000,and 0.587,indicating that the 2017 water resources life cycle sustainability ranks first,followed by 2018 and 2016,2015 is lower.The overall sustainability of the water resources life cycle in Antaibao and Anjialing areas has improved,but there is still much room for improvement.The proportion of freshwater in the water supply is high,the reuse rate of industrial water is still low,and the process stability in the water treatment stage needs to be improved.Saving energy and reducing consumption is an effective way to alleviate the contradiction between the increase in system operation water volume and the increase in environmental emissions and operating costs.According to the results of dynamic tracking and evaluation of the sustainability of the water resources life cycle,from the perspective of the sustainable development of the regional water resources efficient use life cycle,the following continuous improvement feedback information is proposed.One is continuously improving the management model of water resources.The second is to the constant improvement of wastewater classification treatment and cascade water supply;the third is unremittingly enhance the stability of the wastewater treatment process.The fourth is to continually change technology,improve quality,and increase the efficiency of the water system.The fifth is to continue to save energy and reduce consumption,lower the cost.