Dilution levels in mining typically range between 5% and 20%, depending on the mining method and geological conditions. More selective mining methods, such as cut-and-fill, usually aim for dilution around 10%, while less selective methods like open stoping tend to have dilution levels between 15% and 20%(McCarthy, n.d.).
Dilution below 5% is rare and may indicate inaccuracies in resource estimation rather than exceptional operational control. On the other hand, dilution levels above 30% are generally considered excessive and can seriously impact project profitability.
Typical Dilution Ranges by Method:
- Selective methods (e.g., cut-and-fill): ~10% dilution
- Open stoping and similar methods: 15–20% dilution
In complex or challenging geological settings such as steeply dipping or narrow vein deposits higher dilution may occur. However, when dilution exceeds 30%, it often signals operational or design issues that need to be addressed(Understanding the Operation of Grinding Mills in the Mining and Mineral Processing Industry – NEWS – SMMVIK Machinery, n.d.).
Ultimately, acceptable dilution levels vary from mine to mine and should be optimized for each project, taking into account economic cut-off grades, ore body geometry, and ground conditions(Camm & Stebbins, 2023).
Acceptable dilution isn’t just a number it’s a critical reflection of operational control and geological confidence. In your experience, what is a realistic and achievable target for minimizing unplanned dilution in a new underground stope?
Reference:
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Camm, T. W., & Stebbins, S. A. (2023). SIMPLIFIED COST MODELS FOR UNDERGROUND MINE EVALUATION A Handbook for Quick Prefeasibility Cost Estimates—Revised Edition.
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McCarthy, P. L. (n.d.). Mining Dilution and Losses in Underground Mining.
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Understanding the operation of grinding mills in the mining and mineral processing industry—NEWS – SMMVIK Machinery. (n.d.). Retrieved September 17, 2025, from https://www.millvik.com/news/understanding-the-operation-of-grinding.html
