سید فرشید شجاعی

Optimisation of short-term open-pit mining production scheduling is defined as the sequence of block extraction under the limitation of slope and capacities based on minimum production goals deviations. The NPV Scheduler software is a widely used application that addresses this challenge. However, it may not always reach an optimal solution due to using a heuristic algorithm and focus on maximizing discounted cash flow. Additionally, employing a stockpile to blend materials to create a suitable feed for the processing plant can lead to rehandling costs and various disadvantages. In this paper, we propose an optimization model for short-term production scheduling. Our model includes constraints that account for production goal deviations, allowing decision variables to adjust for any deviations that may occur. In the objective function, there is the cost of deviation multiplied by the amount of deviation plus the operating costs (transportation, extraction, etc.). The objective function goal is minimising deviation from production goals and also operating costs. This MIP model was solved using the CPLEX solver in the GAMS software. After two hours and 51 minutes, with a relative gap of 0.07%, a block extraction sequence for each three-month period was obtained without deviation from production goals. Subsequently, using the sequence obtained from the first three-month period, production planning was carried out for 12 weeks. This planning was done without considering transportation costs, and the deviations from production goals and the objective function for all 12 periods are zero.