BlueRock Diamonds

BlueRock Diamonds announced that at the request of the board,
Z Star has updated its 2013 Inferred level of confidence diamond mineral resource for the Kareevlei kimberlite cluster.

Southern Africa – Since the publication of the 2013 report, BlueRock has commenced mining the KV2 pipe and KV1 pipe and conducted geological delineation drilling and bulk sampling on KV5 pipe.

The additional information acquired from the mining and exploration programmes has resulted in an inferred mineral resource update as at November 2018.

The primary changes to the mineral resource are:

  • 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
  • 5.4% increase in grade.

The last Kareevlei revenue estimate of US$232 per carat was conducted in September 2015. 

The Kareevlei production plant was modified in March 2017 and modelled revenues that are aligned with the efficiency of this plant have been estimated at US$323/carat and US$411/carat for the KV1, KV2, KV3 and KV5 pipes respectively.

It should be noted that the production SFD is coarser than that of the original, limited sampling SFD which the mineral resource grade is based on (as indicated by the increased US$/carat modelled).

Investigations are ongoing to ascertain the reasons for this discrepancy and to identify the impact.

“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,” comments BlueRock CEO Adam Waugh.

“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,” he continues.