Force mining, is used to deplete the material of the entire area (Figure 1) in a specific time-frame. This feature is responsible for making MiningMath achieve at least the surface inserted, which means that all the material inside its limits should be extracted, whether is ore or waste. Thus, this feature could be also understood as a minimum depth that should be mined at a specific timeframe.
Keep in mind that these surfaces might be adjusted during the optimization to respect the slope angles (Figure 2), which has a higher priority order on the algorithm, while the optimization is done. Therefore, more material can be mined either to correct the overall slope angle or to increase the NPV.
This functionality is commonly used to refine/keep the mining amount of a previous good surface in early periods, force a specific depth which the deposit should achieve, create custom advances, extract material to make a region available to allocate equipment, etc.
As MiningMath aims to assist the users to apply their project knowledge to guide the algorithm into the best decisions, that is why surfaces are one of the most important constraints hierarchy, which enables the implementation of custom geometries and operational parameters based on this smart hints imposed. Thus, forcing-surfaces might be the reason for disrespecting production limits, blending constraints, geometries, and so on, which require the user to be careful by using these functionalities. To sum up, the material above a Force Mining imported surface will be certainly mined until the specified period of time and what is below it will be mined only if the blocks respect all the other constraints and generate profitable results.
2. Practical example
The approach here was the attempt to deplete a Mining Front with high grade ores in the first period on the optimization, which considers the region which has IY higher than 35, inside the final pit of the Data Validation (Figure 3) and limited until the elevation 250. To build such surface the first step was to place the Z coordinates in this excel file, then use conditional functions to define these limits (Figure 4 and 5).
By having a surface suitable to use, a scenario of Exploratory Analysis was run using the set up of disclosed in Figure 6. Note that a scenario without Force Mining (Figure 7) was also run to have a good comparison.
As a result, the Force Mining surface totally mined along additional material to fulfill the processing capacity and also adjustments on the slope angles which generated the result disclosed in Figures 8 to 10. Besides, it is always useful to compare these scenarios with the ones that did not use this approach, which generates different sequences (Figure 11 and 12) and illustrates how powerful could be user assumptions to generate better results or explore possibilities.