LSE-listed Gem Diamonds has recovered a high quality 202 carat, D colour Type IIa diamond from its Letšeng mine in Lesotho. This is the seventh diamond of over 100 carats to be recovered to date in 2017 from Letšeng, the highest dollar per carat kimberlite diamond mine in the world.
Gem Diamonds has noted an improvement in the size and quality of diamonds recovered at Letšeng with the US$/carat trending positively.
“The market for Letšeng's high-quality diamonds has remained firm and this is anticipated to continue into H2, 2017,” comments Gem Diamonds CEO, Clifford Elphick.
“In addition, the revised life-of-mine plan was implemented during February, with the objective of reducing waste tons mined, improving near term cash flows. We expect to see the benefits emerge during 2017.”
Letšeng treated a total of 1.4 Mt of ore during the period, 75% of which was sourced from the main pipe, and 25% from the satellite pipe.
The balance of the ore was treated through the alluvial ventures contractor plant, which was sourced from the main pipe and low grade stockpiles.
During Q1, 2017 engineering challenges were experienced at both of Gem Diamonds’ Letšeng plants that resulted in lower than planned plant availability.
As a consequence, tons treated in the period were 76 000 tons lower than planned.
The temporary plant availability challenges are being addressed with the contracting partner, and full year guidance remains unaltered.
The contribution from the satellite pipe is expected to meet the original target of 1.8 Mt for the full year.
Gem Diamonds reports that during the period, 25 479 carats were recovered at a grade of 1.53 cpht against an expected reserve grade of 1.61 cpht mainly due to the under performance of the main pipe contact material, which resulted in a mine call factor of 95%.
Mining activities have moved to the centre of the main pipe and grades are returning to expected levels. During Q2, 2017 mining in the main pipe is moving into the higher grade K6 portion of the pipe states Gem Diamonds.
The splitting of the front ends of plant 1 and plant 2 was completed at the end of the period.
This has facilitated the treatment of discrete ore samples based on their individual geo-metallurgical characteristics to better understand the performance of the resource.
Feature image credit: Gem Diamonds