1977年,兰尖铁矿兰2~#溜井由于多年来的严重垮塌,逐渐形成了一个东西宽130米,南北长180米,高达300米,面积为16500平方米,体积为100万立方米的坛形空区。顶部距地表最薄处只有25米,严重威胁着兰山生产安全,影响了采场的合理布局。经多次研究,决定采用大爆破处理塌空区,为了确保大爆破施工的安全,须在雨季前安全,准时起爆。为此,除了用机械化施工 In 1977, due to the serious collapse over many years, Lanjian Iron Orelander 2 ~ # chute gradually formed an east-west 130 meters wide and 180 meters long north-south, up to 300 meters with an area of ​​16,500 square meters and a volume of 1 million cubic meters Altar empty space. The top of the thinnest from the top of the earth only 25 meters, a serious threat to the safety of Lanshan production, affecting the rational layout of the stope. After several studies, decided to adopt a large blasting collapse zone, in order to ensure the safety of large blasting construction, the rainy season before the need to be safe, timely detonation. To this end, except with mechanized construction