A Short-term Production Planning Model for Dimension Stone Quarries

In this paper, problem of short-term production planning for dimension stone quarries was mathematically modeled using a binary integer programming. The model includes an objective function, which was founded as the minimization of the costs due to the total cutting planes of the blocks. This objective may cause to maximization of the net present value (NPV) in dimension stone quarries. During the mathematical modeling the essential constraints are dimension stone quarry capacities and the market demand, block accessibility for the equipment and the reserve constraints. As a base, an optimal size and shape of extractable blocks should be first assigned according to the available extraction technique and the market demand, in order to create a geological block model. Then an economical block model is provided by assignment of a value of “one” for ore blocks and “zero” for waste. Maximum profitability and minimum amount of the ore wastage can be gained using this plan and modeling. INTRODUCTION Providing the amount of dimension stones that is needed for the processing factories (market) can be optimally achieved by means of a short-term production planning. Numerous studies to the problem of short and long term production planning and scheduling in “open pit mining” have been appeared by using the operation research methods in the literatures. But, for such planning in “dimension stone quarrying” industry, there is no considerable study. The production operation and concepts of dimension stone quarrying are partly different than other metal and non-metal open-pit mining. Unlike to the open-pit mining operation which produces ore in form of fragmented materials by bench blasting, in the dimension stone quarrying only the blocks with marketable size and shapes are desired. These blocks can be appropriately provided using the mechanized techniques such as diamond wire cutting and armed-chained cutting machines. A production planning should be shortly set for the blocks extraction with the objective of maximizing net present value (NPV) or profit considering the maximum efficiency, minimum wastage, maximum recovery of the reserves. A certain stone quality was found as the best decision variable for planning dimension stones [1]. A method was also presented for determination of amount of the marketable blocks before extraction operation.