Alternative source of power

Sibanye Gold’s Beatrix mine utilises clean energy

Johannesburg, South Africa: - Aggreko, the world’s leading provider of temporary power and temperature control solutions, has together with Sibanye Gold, delivered an innovative and environmentally friendly alternative source of power to Sibanye Gold’s Beatrix gold mining operations in South Africa that utilises naturally occurring methane gas intersected during underground mining operations. The 2 MW installation generates additional power for Beatrix from fuel which was previously being flared.

Aggreko South Africa began discussions with engineers at Sibanye Gold when they were considering how to produce energy from the methane gas being intersected during underground mining. Until that point, the gas had to be flared on surface to ensure that it was safely removed from the environment. As this was a completely new initiative, an accurate understanding of the reliability of the gas supply was unclear.

Sibanye Gold opted for an Aggreko rental solution as the flexibility of rental meant that the precise amount of generation capacity could be easily tailored to fit the amount of gas supply as it became clearer. It would also allow for any increases or decreases in supply to be quickly adjusted for, ensuring gas wasn’t wasted if supply increased or excess generation capacity remained unused should the gas supply decrease.

“We knew that we wanted to generate electricity from the gas as it was a precious resource that was being completely unutilised through flaring,” commented Dirk van Greuning, Environmental Engineering Manager, Sibanye Gold, “Due to the precise characteristics of the gas supply being uncertain, the flexibility offered by the Aggreko solution was very attractive compared to the option of buying a fleet of generators. The Aggreko team worked tirelessly to adjust and fine tune the installation and manage the gas supply so that now we have an additional 2 MW of power that runs completely on free fuel, which is released naturally underground.”

As the Environmental Engineering managers at Sibanye Gold predicted, the methane supply was shown to vary in terms of the flow, quality and quantity. To address this Aggreko developed an innovative system incorporating a gas accumulator and a methane sensor at its power generators. The gas accumulator acts a reservoir balancing out peaks and troughs in gas supply, while the sensor alerts the system to changes in gas consistency to allow the generators to intuitively adapt to any changes in gas quality.

“The Beatrix project is an outstanding example of successful innovation and value being achieved through the close cooperation and trust between customer and supplier,” commented Martin Foster, General Manager, Aggreko Southern Africa. “Getting the installation just right took both significant effort and investment from Sibanye Gold and Aggreko, but the result is an extremely satisfying vindication for all the hard work.

“Sibanye Gold constantly addresses how we can improve our operations including a strong focus on reducing our environmental impact and reducing cost. This project successfully does both and we are delighted with the outcome,” commented Karel Opperman, Vice President Engineering, Sibanye Gold.