Cut Off Grade Calculator
Enter your mining costs, metal price, metallurgical recovery, and payability to calculate the minimum ore grade required to break even.
Operating Parameters
$
$
Include mining + milling + G&A costs per ore tonne.
%
%
Optional Deductions
%
$
Enter parameters on the left and click Calculate COG
Break-Even Cut-Off Grade
—
g/t
Any ore block grading above this value covers its operating costs.
Price Sensitivity — COG vs. Metal Price
| Metal Price | COG | vs. Base |
|---|
Calculation Breakdown
Formula: COG = (Opex + Refining Charge) / (Metal Price × (1 − Royalty%) × Recovery% × Payability% × Conversion Factor)
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Summary
Enter your mining costs, metal price, metallurgical recovery, and payability to calculate the minimum ore grade required to break even.
How it works
- Enter the total operating cost per tonne of ore processed (mining + milling + G&A).
- Enter the current metal price in your chosen currency per unit (e.g., USD per troy oz for gold).
- Enter the metallurgical recovery as a percentage (the fraction of metal in ore that is recovered to concentrate or dore).
- Enter the smelter payability as a percentage (the fraction of recovered metal that the refiner pays for, after deductions).
- Optionally enter a royalty rate and refining charge to see their effect on COG.
- Click Calculate to get the break-even cut-off grade in grams per tonne (g/t) or percent (%) depending on the metal unit selected.
Use cases
- Determining whether a low-grade ore block should be sent to the mill or to waste.
- Sensitivity analysis: how does COG change when metal price drops 20%?
- Comparing open-pit versus underground economics on the same deposit.
- Scoping studies and prefeasibility mine planning.
- Teaching mineral economics to geology and mining engineering students.
- Quickly checking a contractor's or consultant's COG assumptions.
- Evaluating marginal ore stockpile decisions at existing operations.
Frequently Asked Questions
Last updated: 2026-07-01 ·
Reviewed by Nham Vu