LONG-TERM PLANNING OF AN UNDERGROUND MINE USING LINEAR PROGRAMMING
This paper discusses the formulation of a linear program with the objective of maximizing the cash flows generated over the life of a mine. A mine is split into eleven independent ore zones, each characterized by its reserves, required development and mining method. Based on practical considerations, maximum rates are set for each zone’s development and production capacity. As for the total mine plan, a minimum daily production rate is set along with a minimum feed grade to the mill. A maximum number of development metres per day is set based on the equipment and labour available. Proven and probable ore is mined preferentially over possible ore in the early years of the plan. Furthermore, the fixed cost of operating the mine is taken into consideration whenever mining activities take place.
Once the linear program is solved, it can be critically reviewed, and unrealistic results can be identified. Some resource allocations constraints can then be changed in certain sectors, and new results can be analysed. What-if scenarios can also be examined, such as determining the impact of hiring a contractor to develop a given sector, or dropping an ore zone completely from the plan.