A subsidiary of PJSC ALROSA, Bourevestnik, Inc.,  has  “supplied and commissioned”    27 X-ray luminescence sorters at the new recovery plant of the Cullinan mine in South Africa, ALROSA said recently.

The Cullinan Mine,  owned  74% by Petra Diamonds Limited, is well known as    the source of very rare blue diamonds and large, high quality gem diamonds, including Type II stones characterised by low nitrogen content, ALROSA recounted. So rare are such diamonds that their volume incidence accounts for only 1−2% of the world production.

Petra Diamonds opted for  Bourevestnik’s sorters   after a thorough assessment and comparison of diamond recovery technologies available in the market relative to the unique characteristics of the Cullinan ore, ALROSA declared. “This process confirmed the high recovery efficiency of all types of diamonds by the Bourevestnik sorters, including low-luminescent Type II diamonds characterized by low luminescence level under X-ray exposure,” the Company said.

 Bourevestnik’s   27 sorters which were supplied to Petra Diamonds, were specifically upgraded as per the latter’s requirements, “for primary recovery, reconcentration and final concentrate treatment of diamond bearing ore, with a sizing range of -75 mm +1 mm”.

ALROSA explained: “Processing of Run-Of-Mine material with a size fraction of -75 mm +6 mm is done directly via X-ray sorters without the application of Dense Media Separation.”

Apart from  supplying the equipment, Bourevestnik, Inc. also  undertook the technical training of personnel and arranged a consignment stock of spare parts.