ABSTRACT
Shuichang iron mine is the main supplier of iron ore for the Capital Steel Corporation and also the largest open-pit metal mine in China. Since beginning of this century, the mining operation in Shuichang iron mine has been conducted at deep position below the surface level, which is called “deep-concave mining” (Cai 2001). According to the newest mining programme of Shuichang iron mine, the height of final slope of the mine is 760 m and the deep-concave mining depth is 540 m. Along with increase of mining depth, the slope of the mine is continuously getting higher and higher, which causes that the stability and safety of the slope are getting worse and worse, and the mining excavations are getting more and more difficult. However, on the other hand, increasing slope angle, i.e. making the slope steeper is also an important way to decrease the amount of the striped waste rock and consequently to reduce production cost. For a largescale open pit mine, increasing the slope angle by 1◦ will reduce more than 10 million tons of the striped waste rock and, consequently, save the mining cost about 100 million ChineseYuan for stripping the waste rock, which is a big economical benefit. To solve this contradict problem, it is necessary to make the slope design optimized in which the slope angle is increased as large as possible under a prerequisite condition to ensure the safety of mining operation (Cai 2004).
