西沟矿溜井降段爆破技术实践

Practice of blasting technology in descending section of chute in Xigou Mine

随着台阶面的开采,露天矿山溜井需要进行爆破降段。甘肃西沟矿的1^(#)溜井形状已不规则,常规降段爆破无法保证爆破效果,研究采用大小孔径混合穿孔模式进行降段爆破。首先由FlexiROC T40型潜孔钻机在溜井口周围钻3排Ф90 mm的倾斜辅助孔,倾斜辅助孔与垂直主爆孔衔接,辅助孔提前起爆形成自由面;再由Ф200 mm的主爆孔对整体降段区域的矿石进行爆破破碎,保证爆破振动不会对溜井壁造成破坏,在爆破后72 h内清理井口并恢复使用。通过爆后现场分析和铲装跟踪证实了该方案的可行性,满足安全生产的需要,取得了显著的经济效益。

With the mining of the step surface,the open-pit mine chute needs to be blasted down.The shape of No.1 chute in Xigou Mine in Gansu is irregular.Conventional descending blasting cannot guaran⁃tee the blasting effect.Research has determined that the mixed perforation mode of large and small aper⁃tures is adopted for descending blasting.Firstly,three rows ofϕ90 mm inclined auxiliary holes are drilled around the chute by FlexiROC T40 submersible drilling rig,and the inclined auxiliary holes are connected with the vertical main blasting holes.The free surface is formed by pre-initiation of auxiliary holes.Then,the ore in the whole descending section was broken by the main blast hole ofϕ200 mm to ensure that the blasting vibration did not cause damage to the sliding shaft wall.The wellhead was cleaned and restored within 72 h after blasting.The feasibility of the scheme is proved by field analysis and shovel tracking after explosion,which meets the needs of safe production and achieves remarkable economic benefits.