七角井矿柱回收方案及对相邻矾矿体的安全影响分析

针对七角井铁矿的生产实际,为了安全高效回采2280m中段以上矿柱,同时确保位于铁矿体上盘的钒矿体安全开采,提出间隔间柱抽采和硐室&深孔爆破法、间柱全采与间隔间柱控制爆破堆坝法回收矿柱,并对2个矿柱回收方案进行了模拟仿真。模拟结果显示:采取间隔间柱抽采和硐室与深孔爆破法回收矿柱并处理采空区能够有效控制上盘围岩过度岩移,保证了钒矿体的开采安全,但应注意回收间柱及两侧顶柱后,需立即采用硐室&深孔爆破处理采空区,然后再继续类似间隔后退回采,否则会引起矿柱和上盘失稳。间柱全采与间隔间柱控制爆破堆坝法回收矿柱无法保证上盘围岩的稳定,可能会引起上盘围岩垮塌,影响钒矿体的安全回采。应采用微差爆破技术同时爆破顶、间柱,避免发生顶板跨度过大导致冒落。

Research of Pillars Recovery Scheme and Its Safety Impact Analysis on Adjacent Vanadium Ore Bodies in Qijiaojing Iron Mine

In view of the production practice in Qijiaojing Iron Mine,and in order to safely and efficiently recover the pillars above the middle of 2 280 m and ensure the safe mining of vanadium ore bodies located on the upper part of the iron ore body,both schemes of the discontinuous interval pillar extraction and the chamber & deep-hole blasting method,and the continuous interval pillar extraction and the damming method with controlled explosion of interval pillars were put forward, moreover,pillar extraction under both schemes were simulated. The simulation results showed that discontinuous pillar extrac tion and the chamber & deep-hole blasting method with goaf treatment can effectively controll the excessive rock movement of the surrounding rock and ensure the safe mining of the vanadium ore-body. However,it should be noted that the goaf should be immediately treated by the chamber & deep hole blasting after the recovery of the interval pillar and the roof pillars on both sides,and then the mining should be continued at similar intervals,otherwise the pillar and the upper wall will be unstable. The continuous interval pillar extraction and the damming method with controlled explosion of interval pillars cannot guaran tee the stability of the surrounding rock of the upper plate,which may cause the surrounding rock to collapse and affect the safe recovery of the vanadium ore body. Differential blasting technique with explosion of roof and interval pillars should be ad opted to avoid over-large span of roof which may cause the roof falling.