Permeability improved technology of low permeability seams group in underground mine

according to a poor permeability and hard gas drainage problems of the sean in Songza Mlining Area.bsed on the seam depostiton features of the mining area.the hydrauli fracturing and permeablity improved fechmnology was tested and studied and an efctive pemeabiliy inmproved technical nethod combined with he pressure releasing and permeability improved technology of the protective seam mining and the high pressure hyraulit fracturing nd pemeabilth improved fecom oogy was formed Afer the pressure released and permeailiy inmproved conducted for the protective seam mining the permeabilit rate of the protective seam was increased and up to 2.03×104 times.Afier the high pressure hydrauicfrcturing and permeablit improved technology aplied to improve the permeablit oftheprotsciveseam.the hydrauli fracturing and improved permeatilt radius could be 70 m.After the permeability improved.,the gas drainage volume of a single borehcole was increased by 3 ~ 5 times in average and the gas drainage volume fraction was improved by 3%～20 %. After the two permeability inmproved technologies applied to Songzaol Mining Area,the successtul gas drainage fronm the low permeability seans group was realized and the safety mining of the cal resources in the mine was ensured.