Mathematical programming applied to cement-plant and quarry operations

A large linear-programming model is developed that describes cement operations from the quarry to the market. Separate optimization of clinker composition and quarry scheduling leads to inconsistencies, thereby creating a need for simultaneous optimization. By including both problems and their interfaces in the mode, simultaneous optimization is accomplished. Other factors included in the model are equipment acquisition and assignment, hauling distances and capacities, plant capacities, market prices and demands, and operational costs. Optimization objectives are maximization of net present value, life of mine, or production. Time periods are organized so that long-range profits guide short-range scheduling. Computer implementation of the model is also discussed.