Ordovician limestone karst development law in Feicheng coal field

Being the basement of coal measure strata in North China coal mine, the Ordovician karst aquifer is the baleful source of water for exploiting the Carboniferous coal bed. The coal mines that the exploitation transfers into the deep stratum will be threatened by deep high or super-high pressure confined water from Ordovician. Mastering the vertical development law is one of the basal and prerequisite works for emancipating deep coal resources and ensuring safety for exploiting the deep coal bed. Based on the statistics of exploratory boring data, a slide test and an X-ray diffraction experiment, the results of Ordovician vertical development were obtained. The results are as follows: limestone karsts 0–30 m below the top are undeveloped; those 30–50 m away from the top are the most developed, and those over 50 m are also undeveloped similar to the first ones. The property of the aquifer of the Ordovician limestone karsts from the working face floor (numbered as 101002) in the Caozhuang coal mine is explored using a 3D high-density electrical technique for the well and drill hole data. This confirms the vertical development law and provides evidence for floor prevention and control of water disasters.