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Calcimator

Ore Reserve Calculator

Estimate proven and probable reserves from drill data, cutoff grade, and metal price for mine planning.

Inputs

t
g/t
g/t
%
$/oz
%

Results

Economic Tonnage

857,143 t

Proven Reserve514,286 t
Probable Reserve342,857 t
Contained Metal96,452 oz
Recoverable Metal86,807 oz
Gross Metal Value$164,933,207.00
Above Cutoff85.7%
How to Use This Calculator
  1. Enter drilled tonnage and average grade (ppm or g/t) from drill hole assay data.
  2. Set the cutoff grade (ppm) — the minimum grade at which mining is economic.
  3. Enter proven confidence (%) to split reserves into proven and probable categories.
  4. Input metal price ($/oz) and mill recovery (%) for economic value calculation.
  5. Review Economic Tonnage, Proven Reserve (t), and Contained Metal to report a JORC/NI 43-101 compliant resource summary.

How the result changes with Drilled Tonnage

Drilled TonnageEconomic Tonnage
100,000,90085,715,057 t
350,000,650300,000,557 t
650,000,350557,143,157 t
900,000,100771,428,657 t

What each input means

Drilled Tonnage
Total tonnage estimated from drill data
Average Grade
Average metal grade in grams per tonne
Cutoff Grade
Minimum economic grade for ore classification
Proven Confidence
Percentage of reserve classified as proven (rest is probable)
Metal Price
Current metal price per troy ounce
Mill Recovery
Expected metal recovery percentage in processing

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Drilled Tonnage = 1000000, Average Grade = 3.5, Cutoff Grade = 1, Proven Confidence = 60 = 6 input(s) provided
  2. Calculate Economic Tonnage
    Economic Tonnage
    857143 = 857143
  3. Calculate Proven Reserve
    Proven Reserve
    514286 = 514286
  4. Calculate Probable Reserve
    Probable Reserve
    342857 = 342857

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