Stripping Ratio Calculator
Calculate waste-to-ore ratio and break-even stripping ratio for open pit mine economics.
About this calculator
Stripping ratio expresses how much waste rock must be removed to access one ton of economic ore in an open-pit mine, computed as Waste Tonnage divided by Ore Tonnage (a 5:1 ratio, for example, means 5 tons of waste are moved for every ton of ore mined). This calculator also derives the Break-Even Stripping Ratio -- the highest waste-to-ore ratio the project can sustain and still turn a profit -- from the equation SR(be) = (Ore Value - Processing Cost - Mining Cost) / Mining Cost, which comes directly from setting total revenue (Ore Tonnage x Ore Value) equal to total cost (Total Material x Mining Cost + Ore Tonnage x Processing Cost) and solving for the ratio. Ore Value, Mining Cost, and Processing Cost all move the Break-Even SR -- Waste Tonnage does not, because Break-Even SR describes the ratio the economics can sustain, independent of how much waste a particular pit design actually has. The "Economically Viable?" flag compares the two: it reads Yes only when the actual Stripping Ratio is at or below the Break-Even SR and the Break-Even SR itself is positive (a project with Mining Cost plus Processing Cost exceeding Ore Value has no viable stripping ratio at all, even at zero waste).
When Mining Cost plus Processing Cost already exceeds Ore Value, Break-Even SR is reported as 0 rather than as a negative number: there is no waste-to-ore ratio at which the project pays, and the size of the negative figure the raw algebra produces carries no meaning. That flag is an operating-cost screen, not an investment test: it compares ore revenue against per-ton mining and processing cost only, and takes no account of capital, sustaining capital, G&A, royalties, closure provisions, metallurgical recovery or discounting. All-In Cost per Ton of ore folds waste-removal cost into the ore economics: it is Total Cost (mining every ton of material moved, ore and waste alike, plus processing every ton of ore) divided by Ore Tonnage alone, since only the ore generates revenue.
Inputs
Results
Stripping Ratio
5:1
How to Use This Calculator
- Enter waste tonnage (t) and ore tonnage (t) from the mine plan or block model.
- Set ore value per ton ($/t) and total mining cost per ton ($/t).
- Enter processing cost per ton ($/t) to calculate break-even stripping ratio.
- Review Stripping Ratio (waste:ore) and compare against Break-Even SR to assess project economics.
- Use Economically Viable (Yes/No) as a first screen only — it asks nothing more than whether ore revenue covers per-ton mining and processing at the stated ratio. Capital, sustaining capital, G&A, royalties, closure provisions, metallurgical recovery and the time value of money are all outside this model, and a phase can screen Yes here and still have a negative NPV.
How the result changes with Ore Tonnage
| Ore Tonnage | Stripping Ratio |
|---|---|
| 500,000 | 10:1 |
| 750,000 | 6.67:1 |
| 1,500,000 | 3.33:1 |
| 2,500,000 | 2:1 |
What each input means
- Waste Tonnage
- Total waste rock tonnage to remove
- Ore Tonnage
- Total economic ore tonnage
- Ore Value
- Gross revenue per ton of ore processed
- Mining Cost
- Cost to mine and haul one ton of material (ore or waste)
- Processing Cost
- Cost to process one ton of ore through the mill. Enter 0 for direct-shipping ore that is sold without milling.
How this is calculated
Worked example, using the default values
- Identify Input Parameters5 parametersWaste Tonnage = 5000000, Ore Tonnage = 1000000, Ore Value = 50, Mining Cost = 3, Processing Cost = 15 = 5 input(s) provided
- Calculate Stripping RatioStripping Ratio5 = 5
- Calculate Break-Even SRBreak-Even SR10.67 = 10.67
- Calculate Economically Viable?Economically Viable?Yes = Yes
Engine last updated . Checked against 3 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
What does a stripping ratio of 5:1 actually mean?
It means 5 tons of waste rock must be mined and hauled away for every 1 ton of economic ore recovered. The ratio is simply Waste Tonnage divided by Ore Tonnage; a lower ratio means less non-revenue material has to move per ton of ore, which generally makes a pit cheaper to operate.
How is the Break-Even Stripping Ratio calculated?
It comes from setting total mine revenue equal to total mine cost and solving for the ratio: Break-Even SR = (Ore Value - Processing Cost - Mining Cost) / Mining Cost. Below that ratio the project's ore revenue covers both the waste-removal and processing costs with room to spare; above it, moving one more ton of waste per ton of ore costs more than the ore is worth.
Does the amount of waste rock change the break-even ratio?
No. Break-Even SR depends only on Ore Value, Mining Cost, and Processing Cost per ton -- it describes the maximum ratio the project's economics can sustain in principle, not the ratio a specific pit design happens to have. Waste Tonnage only affects the actual Stripping Ratio you are comparing against that break-even line.
Why can 'Economically Viable?' show No even at a low stripping ratio?
If Mining Cost plus Processing Cost already exceeds Ore Value per ton, the Break-Even SR works out to zero or negative -- there is no stripping ratio, including zero waste, at which the project breaks even. In that case the calculator reports No regardless of how favorable the actual waste-to-ore ratio looks, because the underlying per-ton economics are already underwater before any waste is considered.
Why is All-In Cost per Ton different from Mining Cost or Processing Cost alone?
All-In Cost per Ton of ore spreads the full cost of the operation -- mining every ton of material moved, waste included, plus processing every ton of ore -- across only the ore tonnage, since waste generates no revenue on its own. It is always higher than Mining Cost or Processing Cost individually because it is the true cost burden each ton of sellable ore has to carry.
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