JSE-listed Tharisa has revised its 2019 production guidance downwards on the back of a quarter-on-quarter decrease in output during the first quarter of the year.

The company expects to deliver between 150 000 oz and 160 000 oz of platinum- group metals (PGMs) and between 1.4- million tonnes and 1.5-million tonnes of chrome concentrates during the 2019 financial year.

However, Tharisa plans to continue the implementation of its Vision 2020 projects in the year ahead and maintain its focus on optimising mining and processing performance, which will ensure that Tharisa delivers 200 000 oz of PGMs and two- million tonnes of chrome concentrates in 2020 from the mine by the end of the year.

During the first quarter ended December 31, PGMs production fell 5.9% to 33 600 oz and chrome concentrate decreased 10% to 305 400 t quarter- on-quarter, mostly as a result of reduced recoveries owing to the processing of commissioning tailings to maintain plant throughput, following reduced availability of run-of-mine (RoM) material.

The reduced level of RoM material was supplemented through the reprocessing of 75 900 t of commissioning tailings to maintain plant throughput, comprising 6.4% of combined mill throughput, allowing for a total of 1.19-million tonnes of reef to be milled in the first quarter, a 2% decrease from the last quarter of 2018.

The processing of commissioning tailings negatively impacted on the overall production and recoveries for the quarter.

“Although we had planned for a slower first quarter in terms of mining production, we did not anticipate the full impact of the blending of tailings material would have on our overall recoveries,” says Tharisa CEO Phoevos Pouroulis.

“We will revert back to processing fresh RoM material from mid-January and will achieve our targeted recoveries. We are addressing the operational performance of the mining division, with particular reference to equipment availability and use through proactive maintenance and enhancing the capacity of our drill-and-blast operations,” he adds.

Despite lower mined production volumes, the company’s grade control initiatives yielded positive results, with the PGM rougher feed grade improving by 7.4% for the quarter to 1.59 g/t and the chromium (III) oxide (Cr₂O₃) RoM feed grade improving by 1.1% to 18.5% for the period under review.

Tharisa is focusing on improving its performance through the supplementation of three additional drill rigs on site as the efficiencies of the drill-and-blast operations are dealt with; the implementation of the required preventive maintenance systems to drive equipment availability and use increases; and the commissioning of a new Caterpillar 6050 excavator to increase waste removal capacity as part of the planned asset replacement programme.

Further, by the end of January 2019, mining of the East pit will transition to 24-hour continuous operations, from the current 20-hour operation, to mirror the processing operations, thereby increasing capacity by some 15%.