Dilution generally has a negative effect on metal recovery rates. When waste or low-grade material mixes with ore, it lowers the overall ore grade, reducing the concentration of valuable metals in the feed sent for processing(Ore Dilution & Recovery in Mining – 911Metallurgist, 2017).
This leads to several consequences:
- Lower metal recovery, as processing becomes less efficient due to the reduced ore value(1 New Message, n.d.).
- Decreased revenue, since less metal is extracted per ton of material mined.
- Increased operating costs, because more total material including waste must be handled and processed.
- Deterioration of ore quality, which often forces a mine to raise its cut-off grade to remain economically viable.
- Potential loss of recoverable reserves and shorter mine life, as some ore zones may become uneconomical to extract under high dilution conditions.
For instance, in underground mining, dilution levels vary by method. Shrinkage stoping typically experiences dilution in the range of 5% to 25%, while cut-and-fill methods can often achieve better recovery with less dilution. In contrast, block caving presents a trade-off: although it can offer higher recovery, it often comes with higher dilution, which lowers the average ore grade and affects overall metal recovery(Jorquera, n.d.).
For metallurgists and engineers, maximizing recovery is the goal. What key operational practice do you use to mitigate the negative impact of dilution on metal recovery rates?
Reference:
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1 new message. (n.d.). Retrieved October 14, 2025, from https://groundhogapps.com/unlocking-efficiency-ore-dilution-and-quality-control-in-open-pit-mines/
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Jorquera, M. (n.d.). Underground mining dilution: Management, trends and the role of machine learning.
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Ore Dilution & Recovery in Mining—911Metallurgist. (2017, April 5). https://www.911metallurgist.com/blog/ore-dilution-recovery-mining/
