Ore Grade Calculator

This calculator translates a mining grade estimate into tonnage of metal, the core arithmetic behind reserve and resource reporting. Contained metal is simply total ore tonnage multiplied by grade percentage (containedMetal = tonnage × grade/100) — the theoretical metal present before any processing losses. Recoverable metal then applies the recovery rate, the percentage of that contained metal actually extracted by the mill or plant (typically 85-95% for flotation), giving the tonnage a mine would actually realize. The calculator also flags whether the entered grade is above the cutoff grade — the minimum grade that's economically worth mining given current costs and metal prices — and reports the margin by which it clears or misses that threshold.

Grade is additionally converted to grams per tonne (percentage × 10,000), the unit convention used for precious metals like gold and silver rather than percentage. A metal-per-tonne-of-ore figure (in kilograms) is also given as a convenient multiplier for revenue estimates once you know the metal price. Two simplifications matter here: the model treats the entire tonnage as uniformly at the entered grade — real deposits have grade variability, and this calculator doesn't model a grade-tonnage curve or split ore from waste within a single run — and cutoff-grade economics in practice also depend on mining and processing costs not captured here, so treat this comparison as a quick grade-versus-cutoff screen, not a stand-in for a full mine economic model that also weighs costs and metal prices.