Study On The Reclimaning Of Fault Waterproof Coal Pillar In Mafang Mine

For prolonging the service life of coal mine and reclaiming more coal resource, through particular survey, repeating argumentation, academic analyses and numerical simulation, the project group decided to reclaim the waterproof coal pillar of Mafang coal mine in Shandong province. Using the technology of injecting FCL-C serous fluid into fracture zone of faults, the water transmissibility of F_25-1 and F_east-1 faults can be changed. Using that and other security technology steps, the waterproof coal pillar in faults can be mined safely.The field survey indicates, neighboring mines have no direct impact to Mafang mine. The main aquifer of Mafang mine is Ordovician limestone, it threatens the reclaiming of fault waterproof coal pillar of nine and ten layer coal. And the fracture belt near the fault is the main control factor for extrusive water from ground. The numerical simulations indicate along with the mining of coal the main destruction region concentrates on the bilateral of mined coal and on fault fracture zones, those zones would become bigger and closer to faults. We simulated the ground damage conditions before and after grouting strengthening. The results declare 40 meters longer coal pillar would be reclaimed after grouting strengthening than before. The grout injected into faults can change the property of aquifer, stop up the channel to water source, clog water-guiding crack and strengthen the water-resisting layer of ground. In field, we reclaimed the grouting fault waterproof coal pillar. The total amount of F_25-1 fault waterproof coal pillar is 99. 5 thousands ton, and 45. 2 thousands ton was mined, 45. 2% of the total amount. In F_east-1 fault 30. 4 thousands ton was mined, 87. 1% of 34. 9 thousands ton, the total amount. In general, for fault waterproof coal pillar, grouting is an advanced, simple in process, safety and effective method.