露天矿高深溜井降段技术

摘要

A chute in an open pit mine area need to be descended as the level of mining steps decreases .For the 3# and 4#chute in a open-pit mine mining area in Gansu ,the depth of the chute is all above 400 m ,and the regional geological structure is complex .800 mm thick steel brazed concrete support is used for the borehole wall ,the technical requirements for descending are high and the construction is difficult ,and it is impossible to use the previous situation in which the wellhead is used for blasting descending the free surface.Trenching blasting is proposed to provide a free surface for the chute descending ,then use pre-splitting blasting technology to protect the integrity of the chute supporting body ,finally , through the combination of deep hole blasting and short-hole blasting technology ,to complete the comprehensive descending technology for the chute.The practical application shows that this technology not only satisfies the safety production requirements ,but also achieves good blasting results and economic benefits .%露天矿采区内的溜井,随开采台阶面的下降需要降段.甘肃某露天矿山采区内的3#、4# 溜井,其溜井深度均在400 m 以上,且区域地质结构复杂,井壁采用800 mm 厚钢钎混凝土支护,降段技术要求高、施工难度大,不能采用以往的以溜井口为自由面进行爆破降段,据此提出了一种先通过掘沟爆破为溜井降段提供自由面,再采用预裂爆破技术保护溜井支护体的完整性,最后通过深孔爆破和浅孔爆破相结合,完成溜井全降段的综合性降段技术.实践应用表明,该综合技术不仅满足了安全生产要求,而且取得了良好的爆破效果和经济效益.