Study On Chemical Characteristics And Water Source Discrimination Of Accumulated Water In Goaf Area Of Multi-Aquifer Mine

When mining coal seams in multi-aquifer mines,the water in the goaf is affected by the upper complex aquifers,the water rock interaction and circulation conditions of groundwater will change.Besides,the mining intensity and scale constantly increasing will cause the expending area of the goaf.Therefore,the continuously accumulation of water will threaten the mine safety.It is necessary to study systematically the chemical features and sources of the stagnant water.Take Huangling No.2 Coal Mine as the background mine,this paper comprehensively uses the methods of field exploration and water sample collection,theoretical analysis,hydrochemical analysis,mathematical model and so on.A model for identifying the source of water in the goaf was constructed,verified,and applied to the Xiayukou Coal Mine.Finally get some findings as bellow:This paper divides the ponding area to three parts by analyzing the mechanism of ponding formation.The water-filling sources according to its factors include:surface water,groundwater,other sources and so on,its channels with mainly water-conducting fissures,and the intensity depending on the water yield of overlying roof aquifer.The water is mainly effected by some factors such as:petrological characteristics of top and bottom slabs,mining methods and mining techniques,time etc.The data of water samples analyzed by means of hydrochemical analysis show that the hydrochemical characteristics of surface water,shallow aquifer(Quaternary,Luohe formation)and deep aquifer(Zhiluo formation,Yan'an formation)are very different.The hydrochemical characteristics of deep aquifer and goaf water are similar,which is consistent with hydrogeochemical zonation.The evolution mechanism of stagnant water quality shows that a variety of substances participate in the evolution process,and the action of water and rock is violent.Constructing a discriminant model of the trinity of fuzzy comprehensive evaluation-systematic clustering analysis-grey correlation analysis,Firstly,the water source is confirmed to the Jurassic Yan'an formation aquifer by using optimized fuzzy comprehensive evaluation method.Secondly,through the system cluster analysis and gray correlation analysis,the results show that the similarity between goaf water and Jurassic Yan'an formation water is high,and the gray correlation is high,so the water source is mainly from the Jurassic Yan'an formation aquifer,and a small amount from the Jurassic Zhiluo formation.Thirdly,construct BP neural network model to make simulation analysis.It shows that the main source of water in goaf is identical.The accuracy of the discriminant model is verified,and the results showed that the accuracy of the discriminant model was high and put it to other mines,being in line with the actual situation.