Ordovician Limestone floor inrush water advance treatment technology with surface horizontal branch borehole grouting

In order to solve the water inrush from the high pressurized Ordovician Limestone water of the seam floor, a regional advance treatment method was app lied to the water inrush prevention and control of the Ordovician Limestone aquifer in No. 15445 N coal mining face. With the surface horizontal directional branch bore hole grouting, the water flow channel at the top of the aquifer was sealed and the thickness of the water isolation layer was increased. Then a water prevention gate wa s set at the external gateway of the coal mining face and a water drainage and pressure releasing were conducted. Finally with the detection and monitoring control on t he water pressure and water quality of the floor pressurized aquifer, the water inflow sources and water quality variation could be timely mastered and the sealing effect could be verified. The test results showed that after the 400 m safety mining of No. 15445 N coal mining face advanced forward, the max water inflow quantity of No.3 borehole was reduced from 30 m3/ h to 18 m3/ h and a normal water flow quantity from the floor during the mining period was 48 m3/ h. A good effect was obtained fro m the advance treatment of the Ordovician Limestone water in the region and a target of the pressurized safety mining was realized.