高大丰满熟妇丰满的大白屁股,国产边打电话边被躁视频,99热精品久久只有精品,日韩欧无码一二三区免费不卡

Jinshandian Iron Ore Mine, located in Jinshandian Town, Daye City, Hubei Province, is under Wuhan Iron & Steel Group Minerals Co., Ltd. and is among the four ferrous metallurgical mines that are difficult in mining. It consists of two mining area: Zhangfushan and Yuhuasi.

Pillarless sublevel caving method is adopted. The two mining areas of Zhangfushan and Yuhuasi are integrated and the primary production capacity of mine 1.5 million t/a is extended to 3 million t/a.

Main shaft and auxiliary shaft development is adopted for the mine. The depth of the main shaft is 924 m, and it was the deepest shaft at ferrous metallurgical mines. The application of one-time construction and equipping by stages reduced the effect on mine production in the transition from one stage to another. It is the first time to use double skip hoisting at ferrous metallurgical mines and the hoisting capacity is 3.5 million t/a. The modification and expansion project was put into production in 2007 with good operation.