Study On Tracing Test To Auxiliary Distinguish The Groundwater-bursting Hydrodynamics Of Working Face In Wolonghu Coal Mine

Concerning the water-bursting from aquifers of roof sandstones during coal mining, tracing test is explored to assist the discrimination of water inrush dynamic. In this paper, the principle of tracing test, the detection principle and method of tracer concentration are discussed. The method is used to explain tracer test for the discrimination of recharge source of mine water inrush. According to the tests, the simulation software is used to establish the solute transport model of tracing test. The process and result of tracer migration were simulated. The feasibility of the methods of tracing test and solute migration dynamic process numerical simulation to identify the recharge sources of mine water inrush were comprehensively discussed.Focus on the water-bursting from the roof sandstones aquifers in Wolonghu mine 8101 working face, based on the comprehensive analysis of mine geological structure, and water chemical analysis of water samples from working face, the groundwater from the local mine and the surrounding mines, the program of tracing tests were developed. KI and KBr as tracers are respectively used, putting in the hole named shui-7. The water samples are received and detected the tracer concentration from the drain outside finishing cut line near the gas-discharging hole No.1 and drainage bore of roof aquifer (from 6 coal sandstone aquifer) at the mine pit. A three-dimensional steady flow and unsteady migration model was established to the aquifers with inhomogeneous and anisotropic modelling by FEFLOW.The testing results indicate that hydraulic connection is fairly direct between the K3 sandstone aquifer near the shui-7 hole and the discharge points of the working face. It is found that only a part of the groundwater inrush was from the K3 sandstone aquifer, and the majority of groundwater inrush is supplied by the northern lateral recharge. Simulation results shows that groundwater flows were both from north and south mine borders to the working face, but the groundwater mainly came from the northern border. Near the main groundwater inrush point, the deflection phenomenon of groundwater flow was found. It’s manifested that a part of northern discharge water flow around in the eastern of discharge point, finally flow into the discharge point from the south, and the flow lines at the boundary converge from the north-south direction to the east-west direction. Simulated tracer concentration changes were basically consistent with those in field tracing test which proves that the tracer methods are effective to auxiliary distinguish the sources of groundwater inrush motivation.The recharge sources identified by combining tracing test and numerical simulation of the solute migration dynamic process are mainly from the upper sandstone aquifers of the working face and the northern exogenous recharges. Through the comprehensive analysis of the discriminant method, combined the tracing test and numerical simulation of the solute migration dynamic process to identify the recharge sources during mine groundwater inrush is efficient.