JOHANNESBURG (miningweekly.com) – London-listed miner Gem Diamonds will sell the first 4 028 ct of diamonds recovered at its Ghaghoo mine, in Botswana, in February 2015.

The sale of diamonds from the underground mine, which was officially opened in early September, would be held in conjunction with the sale of diamonds recovered at Gem’s Letšeng mine, in Lesotho, to enable existing customers to participate.

The company noted in an interim management statement on Thursday that development at the mine was progressing in four production tunnels within the kimberlite on Level 1. The final sealing of a fissure within the basalt country rock on Level 1, which led to a significant volume of water flowing into the mine, was in progress.

Gem further reported that the Letšeng mine had produced 28 365 ct in the third quarter of the year, ended September 30. This was down 1% on the 28 623 ct produced in the second quarter, owing to lower tonnes treated as a result of the replacement of a vertical conveyor on Plant 2, as well as owing to a higher percentage of ore being sourced from the Main pipe during the third quarter.

In the quarter under review, two tenders were held for diamonds recovered at the mine, with 23 550 ct sold at an average price of $2 603/ct for total revenue of $61.3-million. Nine exceptional rough diamonds had been sold for more than $1-million each.

Meanwhile, Gem said the delivery of the new $12.5-million coarse recovery plant project at Letšeng remained on track for completion in the second quarter of 2015. X-ray transmissive sorters, which would improve the recovery of high-value Type II diamonds, had arrived in South Africa at the end of October.

In addition, the diamond miner has approved the implementation of the $4.5-million Plant 2 Phase 1 upgrade project at Letšeng, which was expected to increase the treatment capacity of the plant by 250 000 t/y, as well as reduce diamond damage.

Work on the expansion project got under way during the third quarter and would be completed in the first quarter of 2015.

Possible further expansions would be considered once Phase 1 has been completed.