Dilution is factored into resource and reserve estimates to reflect the inclusion of waste or low-grade material that will inevitably be mined along with ore. This adjustment ensures that estimates more accurately represent the material sent to the processing plant, rather than the in-situ ore alone(Maptek – Accounting for Loss and Dilution, n.d.).
Key Methods of Accounting for Dilution:
- Dilution Factors: Historical data, mine plans, or benchmarks from similar operations are used to apply percentage-based adjustments to grades and tonnages(What’s New, n.d.).
- Model Reblocking: Resource models are reblocked to match the Selective Mining Unit (SMU) size, incorporating dilution by combining adjacent ore and waste blocks.
- Edge/Contact Dilution: Waste inclusion along stope edges or geological boundaries is estimated based on design and drilling data, and factored into reserves.
- Mining Practice Simulation: More advanced approaches simulate mining processes (e.g., drilling, blasting) to model how ore and waste may mix during extraction.
Dilution can be applied either globally (as an average factor) or at the block level through modeling software. Both planned dilution (expected based on design) and unplanned dilution (due to operational issues) are considered in reserve estimates and disclosed in technical reports. Accurately accounting for dilution ensures reserve estimates are realistic, supporting better mine planning, economic evaluation, and decision-making.
How do mining companies ensure dilution is accurately reflected in their resource and reserve estimates? Comment below!
Reference:
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Maptek—Accounting for loss and dilution. (n.d.). Retrieved October 13, 2025, from https://www.maptek.com/forge/december_2023/accounting-for-loss-and-dilution/
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What’s New. (n.d.). Retrieved October 13, 2025, from https://webhelp.micromine.com/mm/25.5/English/Content/IDH_WHATS_NEW.htm
