Hydrochemical Characteristics And Evolution Rules Of Mine Water In Shendong Mining Area China

The Shendong mining area is located in the border area between Shanxi,Shaanxi,and Inner Mongolia in northwest China,and is an important coal production base.The mining area mainly mines Jurassic coal seams,and high-strength coal mining generates a large amount of mine water.Due to the combined influence of regional structural conditions,hydrogeological conditions,mining conditions,and other factors,the water quality of the Shendong mining area’s mine water is becoming increasingly complex.and there is a common problem of exceeding the TDS concentration in the mine water,and it has become a major challenge for deep treatment and resource utilization of mine water.Therefore,based on the existing data analysis results,combined with theoretical analysis,on-site testing,indoor experiments,and numerical simulations,this article conducts research on the chemical characteristics and evolution laws of mine water in the Shendong mining area,identifies the chemical characteristics of mine water and its main supply sources in the Shendong mining area,analyzes the main control factors and hydrochemical effects of component formation.And conducts characteristic component dissolution and release tests,found out the release law of main mineral components,and verify the theoretical analysis and laboratory test conclusions in combination with hydrogeochemical reverse simulation,to reveal the evolution law of mine water in Shendong mining area.The main achievements of this article are as follows:（1）Through the water quality data analysis,on-site sampling and testing,hydrogen and oxygen isotope analysis and mathematical statistics analysis,the hydrochemical characteristics of surface water and groundwater in Shendong mining area,the main hydrochemical formation,and the main source of mine water are obtained.As the burial depth increases,the hydrochemical types of surface water and groundwater undergo a transformation from mainly HCO₃-Na·Ca type to HCO₃-Na·Ca type and HCO₃-Na type.The changes in hydrochemical types are mainly controlled by water rock interaction and also influenced by reverse cation exchange.The mine water is jointly supplied by the Quaternary Salawusu Formation phreatic water,Zhiluo Formation confined water,and Yan’an Formation confined water.（2）The results of the characteristic component dissolution release test show that the fine sandstone in the surrounding rock of the study area has the fastest leaching rate and the highest leaching concentration of the main anions and cations during the long-term water rock interaction process,and the highest rate and amount of TDS concentration increase;Based on the analysis results of mineral components,it is concluded that the mineral components that contribute significantly to the increase of TDS concentration during the formation of mine water in the study area are anorthite,plagioclase and gypsum（3）According to the plane distribution characteristics of TDS concentration in mine water,combined with hydrochemical theoretical analysis and dissolution release test of characteristic components,the hydrogeochemical reverse simulation was carried out with the aid of PHREEQC software.It was found that the main reaction of mine water forming high TDS in the runoff process was reverse cation exchange and dissolution.The main minerals dissolved in Zone I,II and III were albite,gypsum,rock salt,albite and dolomite,respectively,Dolomite,albite and rock salt,and based on this,the evolution law of high TDS mine water in Shendong mining area is summarized,which can provide scientific basis for the upgrading and transformation of mine water treatment and resource utilization in Shendong mining area.