JOHANNESBURG (miningweekly.com) – Dual-listed DiamondCorp has reiterated that its Lace diamond mine, in the Free State, remains on schedule to reach full production of 30 000 t/m in July, as production ramp-up from the Upper K4 (UK4) block continues.

The company had, to date, recovered 7 449 ct of diamonds from bulk testing at the 74%-owned mine.

The diamonds recovered from initial processing were meeting expectations in terms of colour and quality, including three diamonds larger than 10 ct, the largest of which was a 22.11 ct H-coloured stone.

This diamond was sold into the company’s South African beneficiation joint venture for $5 000/ct with a view to recovering an 8 ct emerald cut stone after cutting and polishing.

The company would receive a 50% share of the cutting and polishing profit in addition to the price of the rough diamond.

DiamondCorp was, meanwhile, preparing to export 3 577 ct of diamonds, recovered from development and bulk testing activities in the second half of 2015, to Antwerp, Belgium, where they would be sorted ahead of diamond tenders in the coming months.

“At the same time, we are carefully monitoring sentiment in the rough diamond market, which started the year in a slightly more positive mood than the latter part of 2015,” the company said.

PROCESSING PLANT IMPROVEMENTS
Meanwhile, DiamondCorp noted that, during tailings retreatment, management determined that considerable operational efficiencies and water savings could be achieved in the Lace processing plant by increasing the bottom screen size from 1 mm to 1.25 mm.

The change in bottom screen size has been applied to kimberlite processing, which would result in a lower recovered grade but a higher average carat value for the diamonds recovered, as the smallest diamonds were the lowest-value stones.

A final decision on the bottom screen size would be made following receipt of the microdiamond analysis being undertaken as part of the resource statement update and the conclusion of the first few diamond sales, which would provide pricing data for the different diamond size categories.