The notion that plants, in this case wheat, can be used to extract gold from mine dumps seems so far-fetched it’s mind-blowing.
Yet that’s exactly what the research of vivacious and eloquent Tshiamo Legoale, the daughter of a single mother, Barati Legoale from Mogwase near Sun City, has established.
It’s called phytomining. The wheat is planted on dumps and enzymes found in its roots make the gold soluble.
The plant draws this up into its stems and branches where it stores it. Eventually it is burnt and gold is extracted from the ash.
What makes Legoale even more excited about the process is that the wheat seeds, which do not absorb the gold, can be used for food or for the next sowing. Also, wasteland is rehabilitated.
The geologist works in the small-scale mining and beneficiation division of Randburgbased Mintek, a global leader in mineral and metallurgical innovation.
“In this division we work towards poverty alleviation, job creation, small-scale mining and the upliftment of historically marginalised South Africans,” says Legoale.
She’s just returned from collecting rock samples around Lichtenburg in the North West when we meet at Mintek.
“Testing is being done to see if there are diamonds in the area, and if so we hope to transfer mining and beneficiation skills to the communities there,” explains Legoale.
She’s involved in a number of projects at any one time in South Africa.
She was in the formerly rich gold mining areas of the Free State when using plants to clean up toxic sites became a priority.
“Wheat is a big crop there so we began researching how to use it in phytoremediation – using plants to ‘heal’ the soil,” she says.
Her contagious enthusiasm fills the office in the massive high security Mintek complex.
Legoale set out to study all the available literature on wheat as a hyperaccumulator – which means using wheat plants to harvest gold from mine dumps.
“We compared the hyperaccumulatory characteristics of different plants in many tests and trials,” says the CI (chief investigator), as she calls herself.
It was Legoale’s idea to work on wheat, “and I moved from the lab into the greenhouse”.
“But, there’s a lot more lab work still to be done such as increasing the yield from each crop, from about 49% to 80%.”
In an ideal world she would concentrate her formidable scientific mind on wheat and gold and not be involved with other minerals, such as diamonds.
“But South Africa doesn’t have enough scientists to allow us to do that. We need to focus on the needs of many communities.”
She enthuses about working at Mintek: “We have creative freedom and are encouraged and supported.”
Legoale won the FameLab SA competition, Taking African Science to the World, in April this year.
In the middle of June she walked off with the top honours at the international contest, one of the largest of its kind in the world, at the Cheltenham Science Festival in England. It’s a stunning achievement for the grounded and mature young woman who had imagined she would study public relations when she left school. “But my mother believed I was academic material when I was small. She sent me to Bethel High School for Girls, where I developed a passion for science,” she recalls. Her mother had hoped that Legoale’s high marks would attract a bursary and her faith was rewarded when Mintek stepped up to the plate. She obtained her BSc in geology and then honours in mineralogy at the University of the Free State. She’s now studying for her master’s in environmental management at the university. She started as a “scientist in training” at Mintek in 2012 and regards herself as fortunate to be able to help struggling communities as well as work in a laboratory as a scientist. “Usually, we end up being one or the other. I feel I have a balance in my life.” Legoale is the mother of a three-year-old but manages to relax “by watching cartoons with her as well as going to musicals, which I love”.