Application of Surface Drilling Technology in Fault Exploration
According to the previous 3D seismic exploration results of the first panel of Libi Mine,it was found that a DF2 fault developed approximately 90m east of the first mining 3101 working face.In order to further verify and explore the DF2 fault in the central part of the first panel and ensure the safety of the mine production,surface drilling technology was used to construct two boreholes(DF2-1 and DF2-2),totaling 1 700m,and samples were taken within 30 meters of the roof and floor of coal seams 3 and 15 to identify and verify the development characteristics,occurrence,and drop of the DF2 fault.Based on the comparison of the drop of coal seams in the two boreholes,as well as the comprehensive judgment of lithological characteristics,marker layers,and interlayer spacing,this fault is a reverse fault.Combined with previous 3D seismic exploration data on the surface,it is determined that the fault has a strike of N10°E and a dip of N80°W.The hanging wall is located on the west side and the footwall is located on the east side.The lifting of the hanging wall and lowering of footwall cause compression of the strata and coal seams,with a fault inclination angle of about 25 ° and a drop of 31～34m.Based on the observation of borehole hydrology,combined with the hydrogeological conditions of the mining area,the lithological characteristics of the roof and floor strata of the drilling,and the lithological characteristics of the fault plane,it is comprehensively determined that the DF2 fault does not have water conductivity conditions in the construction area.The research provides geological support for the safe production of mines.
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