Strip Ratio Sensitivity Calculator
See how the strip ratio drives your open-pit mining cost per tonne of ore. Enter ore and waste tonnes plus a blended cost per tonne of material, and it returns the strip ratio, the loaded cost per ore tonne, the total mining cost, and how much each extra unit of strip ratio adds.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the ore tonnes and waste tonnes for the pit, stage or block.
- Enter your mining cost per tonne of material (the same rate applied to ore and waste).
- Read the strip ratio and cost per tonne of ore, then vary the waste tonnes to test how sensitive your unit cost is.
How it works
Strip ratio SR = waste tonnes / ore tonnes (tonnes of waste per tonne of ore). Total material = ore + waste. Because every ore tonne must carry SR tonnes of waste, mining cost per tonne of ore = cost per tonne of material x (1 + SR). Total mining cost = total material x cost per tonne. Each +1 in strip ratio adds exactly one material-cost increment to each ore tonne.
Worked example
Worked example. For 1,000,000 t ore, 3,000,000 t waste at $3.00/t of material: SR = 3, cost per tonne of ore = $12.00, total mining cost = $12,000,000.00, and each +1 in strip ratio adds $3.00 per ore tonne.
Common mistakes
- Applying the cost per tonne to ore only — it must be charged on total material (ore plus waste) moved.
- Reading the strip ratio as waste volume; here it is a tonnes-to-tonnes ratio, so densities are already accounted for in the tonnages you enter.
- Using one blended rate when ore and waste actually have very different unit costs and haul profiles.
Frequently asked questions
Is strip ratio by weight or volume?
This tool uses tonnes of waste per tonne of ore (a mass ratio). If your figures are in bank cubic metres, convert to tonnes with the relevant densities first, or interpret the ratio as volumetric consistently.
Why does cost per ore tonne rise so fast with strip ratio?
Because every ore tonne effectively pays to move itself plus SR tonnes of waste. At SR = 3 an ore tonne carries four material tonnes, so its cost is 4x the per-material rate.
Related tools
- Mining Rate Required Calculator
- Mining Recovery & Dilution Impact Calculator
- Capital Cost per Tonne Calculator
- Truck Count Calculator
- Strip Ratio Calculator
- Cost per BCM Calculator
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Tip: Enter any known values to calculate the remaining results.
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