A tool for these times - the capabilities of modern mine planning software


Mr Philippe Lebleu

Considering the current resurgence in commodity prices, every mining company should concentrate on strategy optimization to ensure that operations move from a cost-focused mindset to one centred on value maximization in order to reap the benefits of the upturn in the mining industry. Recent advances in open-pit strategic mine planning software enable the optimization of intricate mining problems associated with a complex and vast array of parameters and constraints. These programs simultaneously optimize the mining sequence, cut-off grade selection, mining equipment number and capital expenditure to maximize the net present value (NPV) of a project or deliver on corporate goals. These modern techniques should be adopted at the strategic or life-of-mine planning level to ensure mines are developed in the most valuable fashion within the bounds of practical mining. Traditionally, mine planning involves following a series of sequential processes to evaluate the merits of different mine planning scenarios. Typically, a mine plan is produced based on fixed cut-off grades and strives to achieve a primary goal, such as a target mill feed, while maintaining a smooth total material movement to simulate the operation of a pre-determined mining fleet. The mine plan is then used as a basis to calculate equipment hours and numbers. The latter form the input into cost models that calculate mining costs and overall project value. The process is repeated with different assumptions for total material movement, sequencing or cut-off grades. Once the mining engineer driving the mine plan is satisfied that an adequate number of scenarios have been evaluated, the best outcome is selected and used for the rest of the process such as waste dump and stockpile design. The problem with this approach is that the entire process can be time-consuming, sub-optimal from a value perspective, especially when the operation being planned is complex, and heavily reliant on the mining engineer’s understanding of the deposit and their experience. That is why the use of advanced mine planning software is becoming more widespread among mining companies and consultancies. Mixed-integer linear programming processes and advanced algorithms allow rapid evaluation of complex problems and help engineers and management make educated decisions regarding the best mine development or optimization strategy to adopt. The power of advanced mine planning software lies in its ability to achieve multiple targets while respecting a variety of constraints by looking ahead to ensure that the choice of mine development made in the first year of production, for example, does not jeopardize its ability to achieve targets in subsequent years and achieve optimum value. This is a vast improvement from a traditional approach whereby a mine plan is derived one period at a time. Despite the advances in mine planning software, mining practicality still needs to be central to a development strategy. To avoid the “black box” solution effect that cannot be explained by the engineer, it is in the engineer’s best interest to produce multiple scenarios to demonstrate the incremental value generated and help tell the story behind the decision-making process. These are only a few of the many applications of modern mine planning software to maximize project value which underline how useful it is as a tool for mining companies to maximize the value extracted from their active mines or future projects.