Resources & Reserves

Diamond Resource and Reserve update for Liqhobong

Diamond Resource

The Diamond Resource was updated at the end of the financial year to account for the mining that took place during the year.
A total of 3.694 million tonnes and 1.103 million carats were depleted. There was a net loss of 0.053 million tonnes containing 0.015 million carats due to changes in the pipe contact. At the end of the year, a total of 0.071 million tonnes of ore and 0.018 million carats was estimated to reside on the ROM, in the pit and in low-grade stockpiles. Therefore, as at 30 June 2019, the total Indicated Resource was 25.234 million tonnes at a grade of 27 cpht containing 6.693 million carats, which is a 13.7% reduction compared to the 2018 Indicated Diamond Resource statement. There were no changes to the Inferred Resource.

Diamond Resource statement for Liqhobong Main Pipe as at 30 June 2019 (including Reserves)
    DIAMOND RESOURCE
Diamond Resource Category Depth from and to Volume in m3 (Millions) Density (Tonnes/m3) Metric Tonnes (Millions) Grade (Cpht) Carats (Millions)
Indicated 2 603 masl to
2 467 masl
9.618 2.62 25.234 27 6.693
Inferred 2 467 masl to
2 127 masl
18.135 2.65 48.064 28 13.553
Total Diamond Resource 27.753 2.64 73.298 28 20.246
Diamond Resources as at 30 June 2019, reported inclusive of reserves.
Tonnes are metric tonnes and totals are rounded.
Stated at a bottom cut-off of 1.25mm square apertures.

Diamond Reserve

The Diamond Reserve was updated at the end of the financial year to account for mining that took place during the year.
Therefore, as at 30 June 2019, the total Probable Reserve was 25.230 million tonnes at a grade of 22 cpht containing 5.623 million carats, which is an 11.6% increase compared to the 2018 Probable Diamond Reserve statement. Improved pit design optimisation initiatives resulted in increased recoverable reserves during the period.
In addition to the Probable Diamond Reserve, the 2017 split shell mine plan also assumes mining of a portion of the Inferred Diamond Resource totalling some 5.5 million tonnes and 1.33 million carats. The latest mine plan contemplates mining of a Cut 1 and Cut 2 and has the optionality to revert to a longer LOM plan, which includes a Cut 3, should there be a general improvement in the project economics including average diamond values or exchange rate, or further optimisation which is made possible by adopting steeper slope angles.

Diamond Reserve statement for the Liqhobong Main Pipe as at 30 June 2019
    DIAMOND RESERVE
Diamond Reserve Category Depth from and to Density (Tonnes/m3) Metric Tonnes (Millions) Grade (Cpht) Carats (Millions)
Probable 2 603 masl to
2 467 masl
2.62 25.230 22 5.623
Total Diamond Reserve 2.62 25.230 22 5.623
The above Diamond Reserve is stated at a 1.25mm slotted screen bottom cut-off.
The average diamond price per carat is estimated at US$77/ct.
The plant is currently using a bottom cut-off configuration of 1.25mm slotted screens which necessitates the application of a resource to reserve modifying factor of 0.84 for mine planning purposes.
Tonnes are metric tonnes and totals are rounded.