BlueRock Diamonds PLC has said that its updated Inferred Mineral Resource for the Kareevlei kimberlite cluster in the Kimberley region of South Africa indicates that the mine will yield a grade that is 5.4% higher than previously inferred. The Company said that the November 2018 study was done to update the earlier 2013 Inferred level of confidence diamond mineral resource.

The company said that since the first study was carried out on the Kareevlei kimberlite cluster (KV1, KV2 and KV3 pipes), mining commenced at the KV2 pipe and KV1 pipe and geological delineation drilling and bulk sampling was conducted on KV5 pipe. The additional information acquired from the mining and exploration programmes has formed the basis for the new report.

Both studies were carried out by Z Star Mineral Resource Consultants.

The 2018 study was based on the addition of a portion of the KV5 pipe to the mineral resource; amendments to the KV2 and KV3 geological models; and the depletion of the mined portion of the KV2 resource.

The net effect of these changes to the Kareevlei kimberlite cluster mineral resource is a 3.0% reduction in tonnes taking into account tonnes already mined; 2.2% increase in carats; and a 5.4% increase in grade.

As per the 2018 study, total resource is now estimated to be 7.74 million tonnes versus 7.89 million in 2013. Its grade is now 4.7 carats per hundred tonnes, up from 4.5 carats. Contained carats for the cluster now totals 367,000, up from 359 000.

Further, BlueRock noted that the earlier revenue estimate of US$ 232 per carat announced in September 2015 has now been changed after the Kareevlei production plant was modified in March 2017. The new modelled revenues are have been estimated at US$ 323/carat and US$ 411/carat for the KV1, KV2, KV3 and KV5 pipes respectively.

Adam Waugh, BlueRock’s CEO commented, “Since operations began in 2014 we have only mined 3% of our Inferred resource and we now have 2.2% more carats than was initially reported in the 2013 estimate. This demonstrates the extremely early stage nature of operations at Kareevlei and the significant upside that remains at our five known kimberlite pipes. KV5 now forms part of our Inferred Resource Statement and our trial mining last year showed that this pipe produces larger, higher value diamonds with an initial estimate of US$411 per carat, so we look forward to unlocking the further value going forward.”