Boundary Optimization Of The Sijiaying Iron Mine And The Influence Of The Surface Constraints

In the process of open pit mining, the determination of ultimate boundary in production of the mine plays a very important position. The ultimate boundary is an important link in open mining design and an important basis in open mine production decision. When determining the ultimate boundary needs comprehensive considering various factors, such as mining resource reserves and ore-body occurrence condition, mining technical condition, the market price of the minerals, ore production cost and so on a variety of complicated factors influencing the mining design scheme.And these factors have direct impact on mining investment and production efficiency, so the high efficient and practical design methods, optimize the final state is mining enterprises inevitable choice.This thesis presents a method for ultimate boundary optimization-"moving cone elimination". This algorithm for open-pit metal mine based on a block model of ore grade and strip ratio. In this method, a largest possible pit is first generated and, then, starting from this pit an iterating cone scanning process is used to eliminate the non-profit cones or cones with strip ratios greater than the break-even strip ratio. The optimum pit is obtained when no such cones can be found in a round of scanning, In the process of exclusion, must ensure that no violation slope angle of geometric constraint, namely, after each part of a realm ruled out from residual level of help slope angle is not greater than the given final slope angle. The algorithm can easily handle different direction and area has different slope angle, through combine conical shell vertex in placed in the center of the lowest level of each grade of ore block model module, can better handle the cone overlap of the adverse impact of the optimization results. Based on this optimization method, this thesis defines the largest geometric boundary delineating, method of the structure of the cone, moving cone elimination idea and algorithm.This thesis takes Sijiaying iron mine as an example, using the moving cone elimination and relevant theoretical knowledge which research and development by Professor Wang Qing. When start a ultimate Boundary optimization, we need to establish a topographic model of the ground surface, a 3D grade model, a step model. Sijiaying iron mine due to its special geographical location and the unique approach to mining. making the state of the mine optimization with usually state optimization have bigger difference. This ultimate boundary optimization is to make two stopes optimized at the same time, but because of the technical and economic parameter in the two stopes not the same, in order to achieve maximum consistent with the mine production status, In the process of optimization the technology of partition line has been used to make the mining stope having the different existing economic parameters partition when optimization at the same time. In this thesis, according to whether considering the constraints of both cases and the three kinds of technical and economic parameter selection (comprehensive, best, worst) is subdivided into six concrete are compared and discuss. Optimization results show that unfettered best boundary mach more larger than the original design realm, west slope (hanging wall) structures "very hard" to the best state of constraints.In this thesis we also are studied by changing the cost and price level of the sensitivity of these factors.Finally comprehensive index analysis, due to the constraint conditions, the mine will lost about 100 million tons of ore quantity, the mass loss of "hanging ore" will appear in the 10 years later, under the condition of the mining constrained production life of the mine is about 26 years, if removed constraints to mining the 100 million tons of ore mining could extend the service life of 5 years for mine, according to the production costs and concentrate prices are 3% annual growth rate and discount rate of 7% computation, the 100 million tons of ore current value (present value) of about 2.38 billion yuan,if we can estimate the cost of to remove the existing constraints at the same time, after comparing the value of the size, The mining enterprises could make decision whether take additional cost to remove the related surface of the building (structure) structures to mining this part of the "trapped" ore.