The Investigation On The Characteristics Of Confined Waterand Safely Mining Technology In North Guizhou Coal Region

Emei mantle plume activities caused the basalt absent, the aquiclude thinner, groundwaterin the supercritical state,CaCO3solubility to increase by95%, karst and sub-rivers welldeveloped in north Guizhou region. The author demonstrated that the abnormal levels ofgroundwater were caused by partial flow in the fractures. The water tables in narrow fractureswere much higher than those in wide ones. The models, numerical simulations and materialanalogues showed that the permeability grew cubically as a function of fracture width incrementin the over burden and the water container due to separation of Changxing limestone and theunderlying layer would develop; the major stress in the floor was in direct propagation to thesquare of the side length of the un-compacted area, the square of water pressure and in inverseproportion to the square of thickness of the floor aquiclude. The tests of injection and ultrasonicprobe showed that the failure happened in the deeper part of the floor ahead of the working faceand water intrusion would go up to cause inrush. The water hazards of separation strata orsub-rivers could be controlled by drilling into the overburden. Water inrush could be controlledby cutting the sides of the open room, reinforcing the coal floor, changing aquifers into aquiclude,stopping fracture expansion by grouting.