Evolution law of mining coal permeability by real-time tracer monitoring system

Selected the 7601 coal caving face in Wuyang coal mine,Lu' an Group Company for the observation site,studied the alteration of coal permeability during mining with SF6 tracer technique.It is found that there are three stages during mining:increasing slowly,decreasing quickly and increasing quickly.The reason for this phe- nomenon is there are three stages for coal deformation:elastic deformation,plastic deformation and plastic failure, in different stages the porosity are different,and the permeability is changing too.