1991年11月25日,承钢马营磷铁矿尾矿库二号排水井突然坍塌,造成13万 m~3 尾矿废水夹杂泥沙流出,污染了下游灌溉农田的水渠和武烈河,淹没部分耕地,并使该矿停产12天。二号排水井坍塌事故的原因,从技术角度分析是封井方式错误。尾矿库管理规程规定:“尾矿库在使用过程中,排水井(塔)、 On November 25, 1991, No. 2 drainage well of Chenggang Phosphorite Tailing Mine tailing pond suddenly collapsed, resulting in the outflow of 130,000 m 3 of tailings wastewater mixed with sediment, polluting the drainage channels and Wulie River of the irrigated farmland in the downstream, inundating part Cultivated land, and the mine discontinued for 12 days. The reason for the collapse of No.2 drainage well is that it is wrong from the technical point of view to seal the well. Tailings Management Regulations: "Tailings in the use of the process, drainage wells (towers),