Application of solid backfill mining under dams avoiding raising waste rock

Aimed at exploiting coal resources under dams safely and efficiently and disposing of gangue excavated underground on a large scale of Jisan coal mine,Yankuang Group,this paper presented a solution of solid backfilling mining avoiding raising waste rock.According to mining geological conditions in pilot area of Jisan coal mine and structural characteristics of Nanyang Lake Dam,proposed a method of gangue preprocessing and transport from advancing face to backfilling working face.Based on technical characteristics of backfilling mining,developed four key equipments in backfilling working face:four-link backfill supports with six props,backfilling conveyor with a bunch of unloading holes at the bottom,a full coal seam compactor and a self-shift transshipping conveyor.According to the protection requirement of Nanyang Lake Dam,determined the security technical measures of filling ratio.When mining was completed at 63_下04-1 working face,the maximum sinking value of the Nanyang Lake Dam was 32mm and the maximum horizontal deformation value was 0.14mm/m,which were both far lower than the predicted value and the dam's deformation extremum,both Nanyang Lake Dam and the buildings around had not occurred crazing damage.