JOHANNESBURG (miningweekly.com) – A well progressing Tharisa mine underground definitive feasibility study accompanied by early works capital deployment is reported by Johannesburg- and London-listed platinum group metals (PGMs) and chrome company Tharisa Minerals in its latest quarterly production report.

In addition is ongoing appraisal of value engineering opportunities at the Karo platinum project in Zimbabwe, where work packages are progressing in line with existing funding.

It was reported in 2023 that, while undertaking a feasibility study, Tharisa would begin shallow underground mechanised operations in the west pit of the Tharisa mine, which is located near Rustenburg in South Africa’s North West. This followed a 2019 prefeasibility study into transitioning underground from opencast.

PGM production in what is the first quarter (Q1) of Tharisa’s financial year 2025 (FY25), was down to 29 900 oz on the 37 100 oz of Q4 FY24, as was chrome production of 374 400 t on the 426 800 t of the previous quarter.

Q1 PGM prices averaged $1 381/oz and metallurgical grade chrome concentrate prices $271/t.

Group cash-on-hand fell to $175.1-million and debt to $86.1-million, bringing about a net cash position of $89-million.

The company incorporates exploration, mining, processing and the beneficiation, marketing, sales, and logistics of PGMs and chrome concentrates as an integrated resource group linked to the energy transition and decarbonisation of economies.

"Undoubtedly a tough start to the new year, impacted by drilling equipment availability. As a consequence thereof, we mined sub optimal oxidised reef horizons, which yielded lower run-of-mine grades and therefore lower recoveries.

“We’ve subsequently improved the drilling rates and equipment availability and the focus this quarter will be on optimising the feed grade and improving our recoveries to previous levels," Tharisa CEO Phoevos Pouroulis revealed in a Stock Exchange News Service (SENS) announcement.

“While we’ve seen a drop in the chrome price due to slowing stainless steel demand, we remain of the view that these price levels are unsustainable and will need to correct to meet expected demand.

“The PGM pricing environment remains stubbornly weak, notwithstanding sound demand fundamentals,” Pouroulis added in the SENS announcement accessed by Mining Weekly.

Regarding the cybersecurity incident, good progress had been made in bringing the affected administrative, accounting and support services systems back online, with work-around solutions minimising disruption.

Production guidance for FY25 is set at between 140 000 oz and 160 000 oz PGMs on a six element basis, and 1.65-million tonnes (Mt) to 1.8 Mt of chrome concentrates.

UNDERGOUND MINING

The prefeasibility underground study undertaken in 2019 and based on mechanised bord and pillar mining was updated in 2021 to allow for changes in the techno-economic mining limits of the openpits.

During 2023, an updated study was completed owing to opencast mining limit changes and subsequent earlier underground transition. The study focused on optimising the decline access strategy and locations and mining method selection.

Investment in downstream beneficiation is starting to pay dividends with the sale of the first commercial chrome alloy to a local industrial user seen as the first step in a beneficiation journey.

A redox flow battery system developed from on-site chrome concentrate is providing an energy storage solution.

Etana will from 2026 likely provide up to 44% of the Tharisa mine’s electricity demand through wheeled wind and solar out of the Western Cape and Northern Cape using the existing electricity transmission grid.

This wheeled energy will complement the mine’s 40 MW solar power plant being developed by TotalEnergies Renewables South Africa and Chariot, which with Etana will ensure that Tharisa Minerals’ target to reduce its carbon footprint by 30% by 2030 is well within reach. Collaboration with Chariot is also under way for similar renewable energy at Karo.