MineEconomics is a free, client-side mining economics calculator built by Ghozian Islam Karami for the Orebit toolkit.
Core formulas
- Revenue per tonne = grade × unit factor × metal price × recovery × (1 − royalty)
- Operating cost per tonne = mining cost + processing cost + G&A
- Cashflow = revenue − operating cost − sustaining CAPEX
- NPV = Σ cashflowt / (1 + discount rate)t
- IRR = discount rate where NPV = 0 (bisection search)
- Payback = first year cumulative cashflow turns positive, interpolated
- Breakeven cut-off grade = operating cost / (price × recovery × (1 − royalty) × unit factor)
Grade–tonnage curve
If no block model is uploaded, a synthetic log-normal distribution is generated from the average grade, coefficient of variation and total in-situ tonnes. The curve is used to estimate ore tonnes above each cut-off grade.
Limitations
- Constant costs and prices are assumed over the mine life.
- Taxes, depreciation, working capital and closure costs are excluded.
- The synthetic grade distribution is illustrative; upload a real grade–tonnage CSV for accurate results.