Surface directional drilling for advance regional water hazard control above multi-layer limestone confined water

GAO Baobin; NIU Gaojie; MENG Wufeng

doi:10.11799/ce202506010

Abstract：To address the controlling difficulty in multi-layer limestone water from Carboniferous Taiyuan Formation in Yongcheng Mining Area,the advance regional control technology was used in the No.21106 working face in Xinqiao Coal Mine to liberate the coal seam threatened by the limestone water in the upper section of Taiyuan Formation.Geological structure of the working face was studied,and the treatment mode of"edge-sealing first and grouting later"was put forward.The grouting treatment horizon was determined according to the location,development,water richness and treatment effect of the aquifer.The law of surface grouting and leakage was studied by analyzing the treatment process data,and the relationship between the two was found by fitting the data.The dynamic grouting was proposed based on the variation characteristics of slurry parameters during the stable pressure grouting stage;The grouting effect was evaluated based on the water flow pattern of the underground verification hole,and an advance regional governance system was established,comprising governance horizon selection,ground dynamic high pressure grouting,delineation of geophysical anomaly area-reinjection of underground blank area,underground drilling verification,underground structural development area verification,and geophysical verification.The results showed that the amount of borehole grouting was mainly used for structure and leakage point treatment;the early-constructed grouting main hole and the structural area were more prone to leakage and the leakage amount is larger;there is a power function relationship between grouting amount and leakage amount;In the steady pressure grouting stage,the key parameters of grouting were dynamically controlled according to the fitting formula to improve the grouting efficiency and ensure the grouting effect.Geophysical prospecting and inspection drilling data show that the effect of advance area treatment was remarkable.The final hole water pressure was reduced from 2.23 MPa to 1.5 MPa,and the water pressure distribution was in an isolated island shape.L10 limestone as a treatment layer effectively increased the thickness and stability of the aquifuge,blocked the water channel and isolates the threat of confined water.The successful application of the research results realized the safe mining of multi-layer limestone confined water working face under complex geological structure.