Chemical Characteristics Of Groundwater And Inrushing Water Source Identification Of Yakou Coalfield

The prerequisite of effective prevention and treatment of the mining water disaster is the correct and fast identification to the sources of inrushing mining water. In this paper, Yakou coalfield of Tongchuan Coal Group was taken as a research object. On the basis of searching and reading relative information at home and abroad, the chemical water characteristics of each main source of inrushing mining water (Quaternary, Permian sandstone and Goaf aquifer Water) are analysed and compared according to the geologic, hydrogeololgic and water chemistry data for years. The relationship between the content of general ions (K++Na+、Ca2+、 Mg2+、Cl-、SO42-、HCO3-) and TDS, the hydraulic connection among each aquifer are also analysed and studied. Further, two discriminate models of the source of inrushing mining water was set up using comprehensive fuzzy evaluation and Grey Relational Analysis respectively and then tested by means of actual case.(1)The comparison of those two models shows that the quality of the Quaternary water is HCO3-Ca·Mg and HCO3-Ca·Na·Mg, the Permian sandstone water is HCO3-Ca·Mg, HCO3-Ca·Mg·Na and HCO3-Ca·Na·Mg, and the Goaf water is mainly SO4-Ca·Mg, SO4·HCO3-Ca·Na·Mg.By the comparison of the ions concentration in each aquifer it can be found that the concentration of SO42-and the hardness of the Goaf anquifer water are higher than the others. The percentage of cationic milligram equivalent in Quaternary water has no much difference with that of Permian sandstone water. However the ion ratio of Mg2++Ca2+and Na++K+in Quaternary water is relatively small.(2)The relationship of the conventional ion content in each aquifer and TDS shows that the TDS in the Goaf water is the biggest,i.e, more than400mg/L generally.The main characteristic anion and cation affectig the increasing TDS in every layer are found out. The analysis and comparison by Piper chart shows that there may be hydraulic connection between the Permian sandstone and Goaf Water.(3)The models set up by the chemical characteristics of six general ions using comprehensive fuzzy evaluation and grey relational analysis have a certain reliability.Thecomparison results of those two models show that the accuracy are all around80%, which canbetter distinguish and fast identifiy the main sources of inrushing water in Yakou Coal Mine.At the same time, the precision of the models still needs to be further studed.This research result has a certain usage value and referential meaning for theidentification of the inrushing water sources of the coal mine and the prevention and treatmentof the mining water problem.