大型叠层分布采空区爆破处理技术

为应对复杂采空区环境下的露天采矿，通过钻孔、激光扫描获取采空区三维形态，结合袁家村铁矿采空区安全顶板厚度研究成果，确定最佳处理时机，在整体推进中兼顾采空区自由面的开辟。以该矿大型、复杂、叠层分布的空25群为对象，采取全高度一次成孔、分区、分层爆破，上下爆破层互为因子，下爆层空25-2矿柱首先起爆，可增加下层空区暴露面积，诱导空区失稳，下爆层呈爆破漏斗向空区内崩落充填，起爆孔中心掏槽作用可创造侧向自由面，能提高能量利用率、改善爆破效果,上爆层近空区顶板几何中心作起爆点，上爆层径向挤压爆破与爆破漏斗复合作用，对下爆层施加二次冲击，促进空区崩落充填，取得了预期的效果。

Blasting Disposal Technology in Large Layer-distributed Mined-out Area

Facing with the complex mined-out area of open pit，a three-dimensional shape of the mined out area was obtained through drilling and laser scanning.Combined with the researches on the safe roof thickness of the mined-out area in Yuanjiacun Iron Mine，the optimum occasion for treatment was determined to open up free space for the mined out area in overall drifting progress.Taking a large，complex，layer-distributed mined out area group No.25 of Yuanjiacun Iron Mine as a case，the explosion of once pore-forming at full height，zoning and layering is adopted.Interaction between the upper and lower blasting layers，and the lower layer firstly blasts of pillar 25-2 at mined out area，can enlarge the exposed area of the lower mined out area and results in the failure of the mined-out area.The lower layer collapses and then fills the gob as a blasting funnel.The centre cutting effect could create lateral free space，enhance energy efficiency and improve explosive effect.The geometric center of the upper blasting layer near the mined-out area roof acts as the initial explosive point，and the combined effect of radial extrusion explosion and the blasting funnel within the upper layer could apply a secondary impact on the lower basting layer and promote the collapse and filling of the mined-out area，with the desired results achieved.