فهرست مطالب سید کاظم اورعی

Loading and transportation are often the most expensive process in an opencast mining operation. Gohar Zamin, being an important reserve with some 600 Million tons of iron ore, is now in the planning stage and an optimum loading and transportation system would add considerably to the economics of its operations. In this paper, two main methods have been introduced. The first method is the conventional shovel and trucks system, whilst the second one is using belt conveyors. The appropriate crushing method decided and the optimum location of the crushers has been determined in both cases. These two methods have then been subject to economic comparison, using real data from field studies in Gohar Zamin mine. The paper concludes that the method of using an in pit crusher and belt conveyors, being technically advantageous, is also more economical than the conventional method

The longwall mining method is one of the best methods for exploitation of undergroundhorizontal to near horizontal coal layers. The high production and safety are the typicaladvantages. Entries of both sides longwall panel having important role in product andsafety. With increasing depth of mine, difficulty of supporting condition of entries increases.One of the basic solutions for such entries stability, particularly at deep mines, is to use yield chain pillars. Since, the behavior of coal pillar at post-peak regime is not known, so th logical designing of these yield chain pillars are not well established.In this paper, two strain-softening models with numerical and analytical fundamentals areanalyzed. These models are studied for a row of yield chain pillar at longwall mining systemat 700 m dept of surface ground. In this study, only development phase of longwall mining system is contemplated while the deformation, yielding and failure possibility are considered before longwall operation runs. Results show in deep longwall mine yield chain pillar can be used. In addition, both analyzed strain-softening models, having required potential for rather optimum understanding of pillar yielding behavior. Therefore, could be a base for yield pillar logical design. Study development shows this approached yield pillar design is sensitive to pillar behavior after coal peak strength. In addition, due to two-dimensional modeling, front abutment load influence could not be evaluated.