Metallurgical Recovery Calculator

Recovered Metal Calculation

Recovered metal is calculated by multiplying contained metal by the assumed metallurgical recovery fraction.

Recovered Metal = Contained Metal × (Recovery % ÷ 100)

For example, 10,000 troy ounces of contained gold at 85% recovery yields 8,500 troy ounces of recovered gold.

Unrecovered Metal Calculation

Unrecovered metal is the difference between the initial contained metal quantity and the metal recovered into the defined product or stream.

Unrecovered Metal = Contained Metal − Recovered Metal

In the same example, 1,500 troy ounces remain unrecovered. This represents 15% of the initial contained metal.

Gross Metal Value

An assumed commodity price can be used to estimate the gross value associated with a recovered or unrecovered metal quantity.

Gross Metal Value = Metal Quantity × Assumed Price per Unit

At an assumed gold price of $4,200 per troy ounce, 1,500 unrecovered ounces represent $6.3 million in gross metal value.

Worked Recovery Example

Consider a material containing 10,000 troy ounces of gold with an assumed metallurgical recovery of 85%.

10,000 oz t × 0.85 = 8,500 oz t recovered

The remaining 1,500 oz t is unrecovered. At an assumed price of $4,200 per oz t, the gross recovered metal value is $35.7 million and the gross unrecovered metal value is $6.3 million.

What Is Metallurgical Recovery?

Metallurgical recovery is the proportion of a target metal in the process feed that reports to a specified recovered product or stream.

Recovery is typically expressed as a percentage and should be distinguished from concentrate grade, which describes metal concentration within the resulting concentrate.

Mineralogy and Liberation

The mineral species hosting a metal, grain size, intergrowths, and degree of liberation can strongly influence processing performance.

Fine-grained or refractory mineral associations may require additional processing or alternative treatment methods to achieve satisfactory recovery.

Processing Methods

Recovery varies with the processing method, including gravity separation, flotation, leaching, magnetic separation, and other beneficiation or extraction techniques.

A recovery estimate is meaningful only when associated with a defined processing route and recovered product or stream.

Metal-Specific Recovery

Different metals within the same deposit may exhibit substantially different recoveries. A copper recovery assumption, for example, should not automatically be applied to gold, silver, or molybdenum.

Each target metal may require its own recovery estimate and supporting metallurgical data.

Metallurgical Testwork

Recovery assumptions may be informed by laboratory tests, pilot-scale studies, or historical plant performance. Representative samples and suitable test procedures are important for evaluating processing behavior.

Results from a limited sample set may not represent all ore types, alteration zones, or operating conditions across a deposit.

Processing Variability

Recovery can change as ore hardness, mineralogy, particle size, feed grade, reagent conditions, and other process variables change.

A single recovery percentage is a simplifying assumption and may not accurately describe performance throughout the life of an operation.

Gross Value vs. Economic Loss

The gross value of unrecovered metal represents the unrecovered metal quantity multiplied by an assumed price. It is not equivalent to lost revenue, lost profit, or an economically recoverable opportunity.

Recovering additional metal may require greater operating costs, capital investment, or different processing methods. Commercial terms and payable-metal deductions can further affect realized value.

Resource and Project Economics

Contained metal, recovered metal, and gross metal value are distinct from mineral resources, mineral reserves, and project profitability.

Economic evaluations require additional assumptions concerning mining, processing, capital and operating costs, commodity prices, recoveries, and other technical and commercial factors.