Research on distributed dewatering test based on the hydrogeological characteristics of sandstone aquifer in coal seam floor
In order to find out the hydrogeological characteristics of Baotashan sandstone aquifer in coal seam floor in Ningdong coalfield,distributed dewatering tests were carried out in two different areas of Shicaocun coal mine.The dewatering tests of the two stages include single-borehole and multi-borehole dewatering tests,and the average calculated permeability coefficient was 0.219～0.301 m/d and 0.024～0.029 m/d,the average water inflow per unit was 0.079 L/(s·m)and 0.012 L/(s·m),and the influence radius was about 700 m and 750 m,respectively.It is found that the thickness of Baotashan sandstone aquifer was about 60 m through the dewaetering test,and the lithology was coarse sandstone with thin sandy mudstone and mudstone.The permeability and water richness of the aquifer were weak and non-uniform,but because the Baotashan sandstone aquifer was located under the lower group coal seam,the water pressure of lower coal group in the study area was above 3 MPa.The ground water temperature of the aquifer was about 41 ℃,and the coal mining activities of the lower group coal workface faced a certain thermal damage.Baotashan sandstone aquifer had good drainage property,the method of water drainage and pressure reduction was the best measure to prevent and control water hazard of sandstone aquifer under the coal seam.The hydrogeological characteristics of the sandstone aquifer in Baotashan were further identified through water discharge tests,which supplemented the hydrogeological conditions that could not be identified through pumping tests,and the exploration results could serve as a basis for the prevention and control of water hazard in coal seam floor sandstone.
Ningdong coalfieldBaotashan sandstonedewatering testdewaetering and pressure reductionhydrogeological conditionswater hazard in coal seam floor
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