Sibanye Gold could be the first mining firm globally to fuel trains with biogenic gas formed over millennia deep beneath the ground in order to cut carbon emissions and costs and improve the health of its workers.

According to Reuters, Molopo South Africa, which holds the country’s first and so far only onshore petroleum production license, said it was partnering with Sibanye Gold to start underground testing next year on a locomotive that has been converted from diesel to run on compressed natural gas (CNG).

Biogenic source

Biogenic gas has been found in South Africa’s Free State province, close to the mining operations of Harmony Gold, Sibanye Gold, and Petra Diamonds.

Although there has been research into its use in powering trains, it has never gone beyond the prototype stage, experts say.

A test run was done with the CNG locomotive that managed to pull eight wagons carrying a 30-tonne load, the equivalent of those pulled by diesel engines, said Molopo director, Marani.

Big milestone

This is a very big milestone to move to the next phase of what we believe is a world first, Marani told Reuters.

There was also a massive reduction in diesel emissions, with big health benefits for mine workers.

The project would also help ease pressure on South Africa’s constrained power grid, said
Sibanye’s vice president of engineering, Karel Opperman.

“A successful implementation will greatly improve our working environment, reduce our carbon footprint, improve the efficiency of our operations,” he told Reuters.

If safety and gas distribution systems are successfully tested, the South African gold producer may start replacing part of its fleet of 570 diesel engines within two years, cutting down miners’ exposure to potentially harmful emissions and saving fuel costs by around 25%.

Replacing diesel-powered machines

Studies show that switching to natural gas from diesel could cut emissions overall by a third.

Molopo, which sent its results to an independent laboratory for confirmation, expects to match or better this given the purity of the zero sulphur biogenic gas.

South Africa’s untapped biogenic gas seeps to the surface along fissures and cracks from deep underground rocks in the Karoo Basin, a vast geological formation that covers about two-thirds of the country and contains the bulk of the coal reserves used for most of its electricity.

Molopo South Africa said it has measured amounts of recoverable biogenic gas at the Free State gas fields of just over 100-billion cubic feet with an upside potential of 1-trillion cubic feet, which was enough to power the country’s gas-to-liquid Mossel Bay refinery for more than a decade.

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