Recoverability
Not all the metal in ore can be extracted. Recovery is the share the processing plant captures, and it depends on the ore's mineralogy and the process used.
2 min read
Recoverability is the share of the metal in the ore that the processing plant actually captures. The rest ends up in the waste.
What it is
Ore is crushed, ground and treated to separate the metal from the rock. No process is perfect. (also called metallurgical recovery) is the percentage of metal that makes it into the final product. The lost metal goes to tailings, the waste left after processing.
What drives it
- Mineralogy. The minerals that hold the metal matter more than the grade. Fine-grained or locked-up minerals are harder to free.
- Oxide or sulphide. Weathered (oxide) ore near the surface and fresh (sulphide) ore below often need different processes and recover differently.
- Refractory ore. Some gold is locked inside sulphide minerals and needs extra, costly treatment to recover well.
- Impurities. Clays, carbon or other minerals can interfere with processing.
- The process chosen. Cheaper processes usually recover less.
Common processes
| Process | Used for | Typical recovery |
|---|---|---|
| Carbon-in-leach (CIL) | Gold | 85–95% |
| Heap leach | Low-grade gold, oxide copper | 50–80% |
| Gravity separation | Coarse gold | Varies; often a first step |
| Flotation | Copper, zinc, lead, nickel sulphides | 80–92% (lead often 70–85%) |
How it is measured
Recovery is estimated through testwork on drill-core samples, in stages:
- Bench-scale tests in a laboratory, early in exploration.
- Variability tests across different parts of the deposit, because recovery can change from zone to zone.
- Pilot-plant tests on larger samples, usually for a feasibility study.
Why it matters
Revenue rises and falls directly with recovery. A drop from 90% to 80% removes about one-ninth of the metal sold, with almost no saving in cost. A deposit with good grade but poor recovery can be uneconomic.
Ranges are indicative and vary widely by deposit. This is educational material, not investment advice.
Key terms
Next in this track
PayabilityA smelter or refinery does not pay for all the metal it receives. Payability is the share it pays for, and it differs widely between metals.Related articles
- Grade and contained metalGrade is how much metal a tonne of rock holds. Multiplied by tonnes it gives contained metal, and the cut-off grade decides which rock counts.Mining economics2 min read
- Cost of productionWhat it costs to mine and process ore, measured per tonne of ore and per unit of metal, and how cash costs differ from all-in sustaining costs.Mining economics2 min read
- TollingInstead of building a processing plant, a mine can pay to process its ore at someone else's plant. Tolling suits small or early projects, with trade-offs.Mining economics2 min read
Educational material only. Nothing here is investment advice or an offer to buy or sell any security or mineral interest.