Reserves & Resources

We manage a world-class resource of over 300 million carats

Petra Diamonds manages one of the world’s largest diamond resources of over 300 million carats (“Mcts”).  This major resource implies that the potential mine lives of Petra’s core assets could be considerably longer than the current mine plans in place at each operation, or could support significantly higher production rates.

Gross Resources

As at 30 June 2016, the Group’s gross Diamond Resources (inclusive of Reserves) increased 1% to 312.16 Mcts (30 June 2015: 308.6 Mcts).

The main reason for the increase in gross Diamond Resources relates to a 42% increase (ca. 2.6 Mcts) in the Resource at Petra’s Combined Kimberley Operations, further to the acquisition of an interest in the Kimberley Mines assets in January 2016, a 6% overall increase (ca. 2.3 Mcts) in the Resource at Williamson further to work carried out during FY 2016 to update the Resource model, and the inclusion of a portion of the overburden dumps at Finsch based on sampling done during FY 2016 (ca. 1.2 Mcts).

These increases were offset by decreases in Resources due to depletion by mining activity at all operations.

Gross Reserves

The Group’s gross Diamond Reserves decreased 4% to 47.9 Mcts (30 June 2015: 49.8 Mcts) due to depletion by mining activity, and re-assessment of remaining Reserves based on mine plan revisions and plant simulation. This includes the update of Reserves at Cullinan (-6% or ca. 1.4 Mcts) which includes depletions and the expected impact of the new plant performance based on metallurgical simulations including bottom cut-off changes, and Finsch (-3% or ca. 0.7 Mcts) due to mining depletions and updates to the Block 5 mining plan.

Summary of Gross Reserves and Resources

The following table summarises the gross Reserves and Resources status of the combined Petra Group operations as at 30 June 2016.

Category Tonnes (millions) Grade (cpht) Contained Diamonds (Mcts)
Probable 103.2 46.4 47.89
Sub-total 103.2 46.4 47.89
Measured 0.2 263.9 0.60
Indicated 441.4 49.8 219.71
Inferred 1,434.2 6.4 91.85
Sub-total 1,875.8 16.6 312.16


Download the Company’s full 2016 Resource Statement

Key Facts

  • 312.16 Mcts Resource: largest outside the majors
  • 47.89 Mcts Reserves