一、方案的提出桦子峪镁矿1962年开始进行第一期建设,1965年正式投产。经过十余年的建设,已初步达到年产50万吨镁矿石的规模,而后又于1976年由鞍山黑色冶金矿山设计院进行了第二期设计。二期设计圈定的露天底标高由原一期的+35米下降到-25米,封闭圈标高为+95米,采场深度为120米(以封闭圈为准)。矿体宽度平均为17米。上盘围岩为千枚岩、云母片岩及滑石片岩。下盘围岩主要是白云岩及级外品矿石。设计安排从1978年开始扩帮过渡,采用缓帮单台阶一次扩到 First, the program put forward Birch Yu magnesium mine started in 1962 the first phase of construction, officially put into operation in 1965. After more than ten years’ construction, the scale of annual output of 500,000 tons of magnesium ore has been reached initially, and then the second phase of design was completed in 1976 by Anshan Black Metallurgy and Mining Design Institute. Phase II design delineation of the open-bottom elevation from the original period of +35 meters down to -25 meters, closed circle elevation of +95 meters, stope depth of 120 meters (subject to the closure of the circle). The average ore body width is 17 meters. The hanging wall rocks are phyllite, mica schist and talc schist. Rock bottom wall is mainly dolomite and grade ore. Design arrangements from 1978 to expand the transition, with a slow to help a single step to expand