Diversified miner Anglo American’s thermal coal business, Anglo Thermal Coal, has developed and patented a bioconversion technology that it believes could significantly reduce the cost and improve the rate and quality of opencast mine rehabilitation.
The bioconversion technology, which claims “to do in six months, or one growing season, what nature does in 60 years” has been trialed at four Anglo American coal mines and, in certain applications, had shown “extremely” positive results, on rehabilitated mining pits and coal discard facilities, said Anglo American mine closure manager Henk Lodewijks in a statement.
Known as Fungcoal, a combination of the words ‘fungi’ and ‘coal’, the R17.5-million project harnessed fungi and weathered coal to produce natural fertilisers that were regarded as the building blocks of soil fertility and plant life.
The project was being undertaken in partnership with Rhodes University’s Institute for Environmental Biotechnology.
The partnership began in 2004 when Anglo Thermal Coal sought ways of accelerating and improving the quality of rehabilitation at its opencast mines.
“Research showed that certain fungi had the ability to break down and liquefy coal that had been exposed to the elements. When accompanied with other microorganisms, they created humic and fulvic acids, which acted as natural fertilisers,” said Lodewijks.
He pointed out that humic and fulvic acids had two important properties. Firstly, they promoted soil microbe and plant growth and, secondly, significantly alleviated the compaction of rehabilitated soil – one of the greatest rehabilitation challenges facing the industry.
“As discard coal was used as a medium on which certain grass species grew, we significantly reduced the need for topsoil, a scarce and costly resource,” explained Lodewijks.
“Our aim is to restore the ecology of land that has been disturbed using organisms that cannot be seen with the naked eye,” he said.
Rhodes University professor Keith Cowan added that all organisms act in concert and enable the environment to ‘resurrect’ itself, further stating that the research team had been fortunate to discover in a relatively short time fungi and bacteria that were so important to the process.
“We are finding a complete toolkit of organisms for land that has been disturbed to ensure that it can be returned to communities for economic activity almost immediately after mining has ended,” Cowan commented.
The next step in the project would be to establish a thorough record of land that had been rehabilitated with Fungcoal and gain a greater understanding of Fungcoal’s use in other applications and over a longer time.
Engagement with regulators would take place as the project moved closer to the commercial phase.