Technological yesearch on water source identiftcation of coastal coalmines based on PCA-RA

The occurrence of mine water hazards during coal mining has seriously threatened the safety of coal mines.Determining the quantity and type of water sources is of great significance to the prevention of water hazards.In order to determine the quantity and type of mine water supply sources in coastal coal mine, taking Liangjia Coal Mine in Longkou as an example, different water bodies (mine water, quaternary water and accumulated water in the subsidence area) in the mining area were sampled respectively, and mine water sources were identified based on hydrochemistry and principal component analysis residual analysis (PCA-RA).The results show that the contents of main chemical components in Quaternary water, accumulated water in the subsidence area and mine water in Liangjia Coal Mine area are quite different, and are affected by seawater intrusion.In terms of mean value, the mass concentrations of cations and anions in mine water have the relationships of Na+>Ca2+>Mg2+>K+and HCO-3>Cl->SO2-4>Cl-, respectively.In different water bodies, Cl-and Na+are dominant anions and cations, and the hydrochemical type is mainly Na-Cl type, and there is a certain hydraulic connection among the three water bodies.The selected water chemistry data is suitable for PCA, but the number of principal components is only determined based on the criterion that the characteristic value is greater than 1 or the cumulative variance contribution rate is greater than 85%, which cannot well represent all the information of the original data.Based on the method of water chemistry and PCA-RA, it is determined that there are five recharge sources for mine water in Liangjia Coal Mine, namely seawater, HCO3-rich bedrock water, accumulated water in the subsidence area, mixed water and Quaternary water.The PCA-RA method can effectively process and characterize the information of the original water quality data, and it can be more reasonable to determine the type and quantity of the recharge source of mine water.The research results can provide a certain scientific reference and basis for the prevention of water hazards in the coastal coal mine area.