露天采场高陡边坡下深部采空区的爆破处理研究

Study on Blasting Treatment of Deep Goaf under High and Steep Slope in Open-pit Mining

鞍本地区是我国最大的BIF型铁矿集中分布区,其铁矿资源量/储量约占全国总量的1/4,但由于日伪时期的掠夺式开采和矿业整合开发前的无序开发利用,在一定深度空间内遗留了大量隐伏采空区,为后期实现规模化露天开采带来极大的安全隐患,成为制约露天铁矿资源安全高效开采的难题。以弓长岭露天铁矿大砬子采区高陡边坡下的深部采空区为研究对象,利用LS_DYNA软件进行采空区的安全爆破模拟研究,结合现场深部采空区爆破参数试验结果,提出了采用孔中起爆处理采空区的方法,具体参数设置为空区预留顶板厚度3 m,孔间延期时间42 ms,排间延期时间75 ms,平均炸药单耗0.237 kg/t。在上述分析的基础上,针对大砬子露天采场高陡边坡内的深部不规则多层采空区提出了分层、分区安全爆破处理的技术方案,且空区边界用切割爆破方法处理,爆破处理效果良好,采空区得到了安全有效治理。

The largest concentrated distribution area of BIF-type iron deposits is Anben area in China,and its iron oreresources reserves account for about 1/4 of the country′s total.The development and utilization left a large number of concealedgoafs in a certain depth space because of the predatory mining during the Japanese and puppet periods and the disordered ex-ploitation and utilization before the integrated exploitation of the mining industry,which brought great safety hazards to thelarge-scale open-pit mining in the later period,and became a problem restricting the safe and efficient mining of open-pit ironore resources.In order to solve the above problems,taking the deep goaf under the high and steep slope in the Dalazi mining ar-ea of the Gongchangling Open-pit Iron Mine as an example,and using LS_DYNA software to simulate the safe blasting of themined-out area.Based on the simulaiton results and the test results of blasting parameters in deep goaf,the safety treatmentmethod for explosion in the hole is proposed.The specific setting parameters are the reserved roof thickness of 3 m in the goaf,the delay time between the holes is 42 ms,the delay time between the rows is 75 ms,and the average unit consumption of ex-plosives is 0.237 kg/t.Based on the above discussion results,a layered,zoned and safe blasting technical solution is proposedfor the deep irregular multi-layer goafs in the high and steep slopes of the Dalazi open-pit stope.The boundary of the goaf istreated with cutting blasting,and the blasting treatment effect is ideal,therefore,the goaf has been effectively and safety man-aged.