In line with its strategy of the early detection of large diamonds and reducing diamond damage, LSE-listed Gem Diamonds has approved the construction of a $3-million pilot plant, at Letšeng, in Lesotho, that will use innovative technology to identify diamonds within kimberlite ore and nonmechanical means of liberating the encapsulated diamonds.

The pilot plant will be commissioned in the second quarter of 2019.

Gem CEO Clifford Elphick on Wednesday said the results of the proof of concept trials to identify and liberate diamonds within kimberlite ore have progressed well, leading to the decision to test this technology on site at Letšeng as part of a pilot project.

Meanwhile, in a trading update to shareholders for the third quarter of this year, the diamond producer said it remained on track to achieve its cumulative target of $100-million in incremental revenue, productivity improvement and cost savings for the four-year period to end-2021.

Additionally, the formal sale process for the Ghaghoo diamond mine, in Botswana, continues.

During the third quarter, Letšeng recovered two diamonds greater than 100 ct. After period-end, on October 15, a 357 ct diamond was also recovered, thereby bringing the number of diamonds greater than 100 ct recovered to date this year to 13.

“. . . the thirteenth diamond greater than 100 carats for 2018 was recovered, resulting in the highest number of these recoveries in a single calendar year,” Elphick commented.

Letšeng recovered 35 755 ct of diamonds during the period, which represents a quarter-on-quarter improvement of 27%.

Eight diamonds were sold for more than $1-million each, generating revenue of $21-million during the period.

Letšeng treated 1.5-million tonnes of ore during the quarter, 54% of which was sourced from the main pipe and 46% from the satellite pipe. The remaining balance of the ore was treated through the Alluvial Ventures contractor plant.

Waste stripping continued in line with the requirements of the long-term mine plan, the company said on Wednesday.

Following the successful replacement of the scrubber shell and other significant maintenance during the major shutdown in Plant 2 during the second quarter, plant utilisation and availability returned to nameplate capacity resulting in increased tonnages treated for the period.

Meanwhile, following improved mining efficiencies, strong production during the period and consistent grade recoveries, Gem has revised its production guidance for the full-year upwards.

It now expects to produce between 120 000 ct and 124 000 ct of diamonds for the full-year, compared with the previously guided 114 000 ct to 118 000 ct.