CONTAINED METAL
Contained Metal Calculation
Calculate contained metal using tonnage and average grade.
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MINING & RESOURCE CALCULATIONS
Contained Metal Calculator
Estimate the quantity of contained metal in a mineralized tonnage using average grade and common mining and assay units.
GRADE & CONTAINED METAL
Calculate Contained Metal
Enter the mineralized tonnage and average grade to estimate the total quantity of metal contained within the material.
FORMULA
Contained Metal Formula
Contained metal is estimated by multiplying the quantity of mineralized material by its average grade. The calculation depends on how the grade is expressed.
Percent Grade
When grade is expressed as a percentage, convert the percentage to a decimal fraction before multiplying by tonnage.
Contained Metal = Tonnage × (Grade ÷ 100)
For example, 1,000,000 metric tonnes grading 1% copper contains an estimated 10,000 metric tonnes of copper.
Grams per Tonne
When grade is expressed in grams per tonne, multiply the grade directly by the tonnage expressed in metric tonnes.
Contained Grams = Metric Tonnes × Grade (g/t)
For example, 1,000,000 metric tonnes grading 1 g/t gold contains 1,000,000 grams, or 1,000 kilograms, of gold.
Parts per Million
For solid geological materials, one part per million by mass is numerically equivalent to one gram per metric tonne.
1 ppm = 1 g/t
This allows ppm grades to be handled using the same mass relationship as grades reported in grams per tonne.
Ounces per Short Ton
When grade is expressed in troy ounces per short ton, the mineralized tonnage must be expressed in short tons before multiplying by grade.
Contained Troy Ounces = Short Tons × Grade (oz/short ton)
A deposit containing 1,000,000 short tons at 1 oz/short ton therefore contains an estimated 1,000,000 troy ounces.
INTERPRETATION
Contained Metal vs. Recoverable Metal
Contained metal describes the total quantity of a commodity implied by the tonnage and average grade of mineralized material. It should not be interpreted as the quantity of metal that can ultimately be produced.
Contained Metal
Contained metal is a mathematical estimate based on tonnage and grade. It describes how much of a commodity is present within the specified quantity of mineralized material.
Metallurgical Recovery
Mineral processing rarely recovers all of the contained metal. Recovery depends on mineralogy, processing methods, ore characteristics, and metallurgical performance.
Mining Dilution & Losses
Mining can introduce waste material into ore or leave some mineralized material behind. Dilution and mining losses can therefore change both the tonnage and grade delivered for processing.
Resources & Reserves
A contained-metal calculation alone does not establish a mineral resource or mineral reserve. Formal estimates require geological interpretation, sampling, estimation methods, and appropriate technical and economic considerations.
APPLICATION
Why Calculate Contained Metal?
Contained-metal calculations provide a convenient way to translate tonnage and grade into an estimated quantity of a commodity.
Resource Evaluation
Tonnage and grade can be converted into contained metal to help communicate the overall scale of a mineralized body or geological estimate.
Deposit Comparison
Contained metal can provide additional context when comparing deposits that differ substantially in tonnage and average grade.
Exploration Context
Early geological estimates can use approximate tonnage and grade to illustrate how changes in either variable affect the implied quantity of contained metal.
Unit Awareness
Correct unit handling is essential. Metric tonnes, short tons, grams per tonne, percent, ppm, and ounces per short ton cannot always be combined directly without conversion.