The Study on Water-richness of Thin Limestone Aquifers in North China Coalfields

To obtain the evaluation results that are more in line with the water-richness of thin limestone aquifers for ensuring the safety of coal mine production, dewatering test and hydrochemical analysis were conducted on Benxi thin limestone aquifer to explore and quantify the hydraulic connection between the Ordovician limestone aquifer and the thin limestone aquifer in Benxi formation. Based on the characteristics of water-bearing media, such as aquifer thickness, core recovery, flushing fluid consumption and permeability coefficient, the CRITIC weighting method was used to determine the weight of each factor’s influence on the water-richness of thin limestone aquifers, so as to establish the model for evaluating the water-richness of thin limestone aquifer in Benxi formation, and draw the thematic map of the main controlling factors of the aquifers. Then, the information was normalized and superimposed using the multi-source information fusion technology, thereby obtaining the zoning of the aquifer per different water-richness. The evaluation results show that the thin limestone aquifer in Benxi formation can be divided into five areas, i.e. “strong, relatively strong, medium weak, relatively weak and weak ” areas. With a stronger hydraulic connection with the Ordovician limestone aquifer, the northwest part of the research area has a greater water-richness than the southeast part, which was verified by the pumping test carried out in the study area.