1992年5月27日,甘肃成县白银公司厂坝铅锌矿成功地进行了二期边坡工程1865t级的定向控制大爆破。该爆破工程装药量居国内第四,是四十多年来最大的边坡工程控制大爆破。共掘进坑道3005m,爆破岩石165.5万m~3,炸药平均单耗1.1kg/m~3。爆破的目的是:夷平二期采场东山头,使其下降80m;保护采场北部边坡和三条大型汽车隧道。由于一期采场已生产,北边坡高300m,爆区北端距药包65m处有Ⅰ~＃隧道.南端离药包斜距150m处有 On May 27, 1992, the Zhungengba Lead-Zinc Mine in Chengxian County, Gansu Province successfully conducted the 1865t large-scale directional control blasting of the second-stage slope project. The blasting charge ranks fourth in the country and is the largest blast control project in more than 40 years. A total of 3005m tunneling, blasting 16565000 m ~ 3 rock, explosives average unit consumption 1.1kg / m ~ 3. The purpose of the blasting is to: Pingping Dongshan first stope, to make it down 80m; to protect the northern slope and three large mining tunnel. As a stope has been produced, the north slope of 300m, the northern end of the burst area from the kits 65m Department Ⅰ ~ # tunnel south of the drug package away from the slope 150m