Experiment Study On Laws Of Relieved Methane Delivery By Protective Layer Mining

Released protective layer induces overlying strata fracturing and changes on originalporosity and permeability of coal-rock mass. Studying on the laws of gas seepage in pore andfissure medium and its coupling with the deformation of coal and rock on influence of miningactivities is theoretically important for establishing the scientific extraction method and effectivegas disaster preventing techniques. Comprehensively using the theoretical analysis and similarsimulation experiment methods, studying on movement regularity of strata in the process ofprotective layer mining activities and the seepage laws of released methane. The main work is asfollows:(1) Analysis the characteristics and classification of the protective layer mining andmovement regularity of strata on influence of mining activitie and the seepage laws of releasedmethane.(2) Research and development of experiment system of coal and gas together mining,self-developed the enclosing box, ctive mining device of protective layer, flexible loadingdevices of strata and measurement device of gas seepage speed.(3) Making similar simulation experiment of lower protective layer mining, nitrogen (N2)instead of methane (CH4) filled with experiment system. Through the experiment data analysis,the coal and rock mining-induced fractures have three processes of form, the expansion and theclosure, Abscission layer fracture produced than earlier across layer fracture. Along with theadvance work plan, process of released gas seepage speed in protectived layer is rise, down, andincreased to reduce again, finally be stable.