Meikuang Anquan (Nov 2022)
Characteristics and water abundance evaluation of concealed burning area in southern of Ningtiaota Coal Mine
Abstract
Coal seam fire area is widely distributed in western coal area of China. When there is a strong hydraulic connection between the burned rock aquifer and other aquifers in the coal seam fire area, it will pose a serious threat to the safe mining of coal mine. Taking the 1-2 upper coal concealed burning area in the southeast corner of Ningtiaota Coal Mine as an example, based on various past hydro-geological data, the ancient topography before the deposition of Baode Formation was restored, and the stratum characteristics of the concealed fire area and the geological characteristics of the compensation channel drainage were analyzed. The factor analysis method is used to extract the characteristic factors reflecting the water abundance of burnt rock and weathered bedrock aquifer, and the comprehensive water-rich zone of burnt rock and weathered bedrock aquifer is obtained through GIS superposition method. The results show: the 1-2 upper coal seam burned from the early Cretaceous to the Pliocene, the development of ancient gullies provides favorable conditions for the formation of spontaneous combustion and burning metamorphic rocks in coal seams; the burnt rock aquifer and weathered bedrock aquifer in the concealed burning area are basically connected together to form a unified aquifer; the overburden rock combination relationship on 1-2 upper coal concealed burning area can be divided into three types, namely burnt rock-weathered bedrock combination, coal seam-burnt rock-weathered bedrock combination, coal seam-burnt rock-normal bedrock-weathered bedrock combination. Strong water abundance areas are mainly distributed in a small area in the north and west of the burning area, the medium water abundance areas are distributed in the burning area in a belt along the northwest-southeast direction; the eastern and northern areas of the concealed burning area are relatively weak in water abundance; the weak water abundance areas are distributed outside concealed burning area. Compared with the water inflow of underground water exploration and release boreholes, the evaluation of water abundance is in good agreement with the practice.
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