It is now time to conclude our series on how to optimize mine sequences using the concept of ‘best and worst case’ adopted from open pit mines. In our previous posts, we provided an example of this concept in real footprint at the Regal deposit. Discover the results and download the full article at the bottom of this post.

FINAL RESULTS FOR SEQUENCE SELECTION

Comparing all the options evaluated for the Regal deposit, the best option divided the footprint into two zones. The sequence starts in the middle of both zones moving with a V-shape first East then West. It is clear that the benefits are not only economical, since the operation of two zones is much easier and offers more flexibility. The comparison between sequences for two zones versus the entire footprint is shown in Figure 17. More work needs to be completed to detail the final sequence model given this was just a quick analysis of a number of different options, however this tool provides strong evidence for alternatives that could be modeled for an optimal result. The next step is to take these results and create a model in GEOVIA PCBC™, where the footprint can be modelled explicitly by drawpoint adding more resolution and detail to the analysis including opening sequence details by month and by zone, and a more sophisticated dilution/mixing model added as a 3D Cellular Automation.

CONCLUSION

The results presented in this series demonstrate that the mine sequence optimization for block caving using the concept of ‘best and worst case’ is a very useful tool for a mine planner to get a maximum and minimum value limit for a sequence, creating a valid reference to compare any sequence created using all of the typical constraints for a block cave mine. Also it is helpful to have the opportunity to generate and evaluate several runs at once and to be able to see the impact of the cave front shape, orientation, starting point, etc. on the production schedule and final NPV. This is not a complex mathematical optimization solution for this problem since it is a simple iterative process, however it provides the advantage of a very easy and straightforward method to evaluate many different scenarios that provide enough information to make the right decision in short period of time.

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