Ore Reserve Tonnage Calculator

Work out ore reserve tonnage instantly with clear inputs, formula shown and shareable results.

About Ore Reserve Tonnage Calculator

In-situ tonnage is area times thickness times specific gravity. Mining recovery then removes ore left in pillars, lost to dilution boundaries or unmineable geometry — typically 8-15% in underground mining and under 5% in open pit. Only the recoverable figure belongs in a reserve statement.

Formula

Reserve tonnage

In-situ tonnage = area x thickness x specific gravity; recoverable = in-situ x mining recovery

Worked example

With the default values below, Ore Reserve Tonnage Calculator returns Recoverable Ore Tonnage of 7,452,000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Deposit Areaminimum 0 m2: 250,000 m2
Average Thicknessminimum 0 m: 12 m
Ore Specific Gravityminimum 0.01: 2.7
Mining Recoveryaccepts 0.01–100 %: 92 %

Results

Recoverable Ore Tonnage: 7,452,000
In-Situ Tonnage: 8,100,000
Ore Volume: 3,000,000
Tonnage Lost To Mining Recovery: 648,000

Step by step

1Values used
2Reserve tonnage
3Recoverable Ore Tonnage= 7,452,000
4In-Situ Tonnage= 8,100,000
5Ore Volume= 3,000,000
6Tonnage Lost To Mining Recovery= 648,000

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Mineral resource and reserve estimates for public reporting must be prepared under a recognised code such as JORC, NI 43-101 or PERC by a competent or qualified person.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Mineral resource and reserve estimates for public reporting must be prepared under a recognised code such as JORC, NI 43-101 or PERC by a competent or qualified person.

Frequently Asked Questions

What is the difference between a resource and a reserve?

A resource is a geological estimate. A reserve is the part of a measured or indicated resource that is economically mineable after applying modifying factors including mining recovery, dilution, cost and price.

Why does specific gravity matter?

It converts volume to mass, and errors propagate directly into tonnage. It must be measured on representative samples, since it varies with mineralogy, porosity and moisture.