Abstract: At present,large-dimater deep hole backfilling mining method is adopted in Dongguashan Copper Mine,the stope roof failure effects is not satisfactory,mining loss rate increases sharply.Through investigation,the causes of low stope roof failure rate of the mine is discussed.The results show that the problems such as poor hole layout,overmuch detonator segments and shorter of the reserved length of blasting holes orifice are existed in the process of stope roof failure by hole blasting technique.Besides that,the corresponding technical measures for improving stope roof failure rate is proposed by selecting the reasonable layout of blasting holes,adjucting charging structure of blasting holes and reducing detonator segments.The application results of the above technical measures show that the stope roof failure rate is improved from 93.7% to 98.9%,the parctice results is statisfactory,which can provide reliable for the similar mines.

Key words: Large-dimater deep hole backfilling mining method, Deep hole blasting, Stope roof failure rate, Charging structure