• Mining

Stampriet’s uranium dilemma

- 2022-08-30 00:00:00

Omaheke Region governor Pijoo Nganate says mining and farming can coexist. This despite fears that mining activities could damage the Stampriet aquifer which provides groundwater resources to communities living in the Omaheke and Hardap regions as well as adjacent communities in Botswana and South Africa.
Headspring Investments, a subsidiary of Uranium One, part of the Russian state-owned nuclear corporation Rosatom, is currently conducting exploration drilling on Farm Tripoli, situated 15 kilometres west of Leonardville.
“It is a golden opportunity for us as a country to prove that mining and farming can coexist,” Nganate said. He added that there was little to be concerned about at this stage as actual mining had not commenced yet. “This is a new method of drilling and we need to sensitise our people,” he added.
Mines deputy minister Kornelia Shilunga said communities should put their faith in government to fulfil its oversight role. “We so many times hear about complaints that mining is destroying the environment and that it is affecting the lives of our people. We have to trust the institutions that we have and society must also trust our government,” she said.
Headspring Investments has held an exclusive prospecting licence for uranium since 2011 in an area covering 7 000 square kilometres. The company said it is considering investing US$500 million once it gets approval for its mining project.
Already the company has drilled 600 boreholes and 29 hydrological boreholes since 2019. Meanwhile, the Namibia Agricultural Union welcomed a decision by the ministry of agriculture, water and land reform to withdraw two permits issued for the drilling of 37 boreholes for exploration and hydrogeological purposes in the Stampriet basin.
“Should uranium mining be allowed, it could render the water in the south-eastern region of Namibia unfit for human and animal consumption, effectively bringing agriculture to a total and permanent standstill in the area,” its president Piet Gouws has said.
Dr. Roy McG. Miller, consulting geologist with more than 40 years’ experience in the Namibian mining industry agrees. “The whole area is entirely dependent on the high-quality artesian to subartesian groundwater for its survival. There is no other year-round supply of water,” he says. “The water table in the basin is so high that the uranium cannot be mined by conventional open-pit or underground mines. It can only be mined by a process called in-situ leach (ISL) mining,” he adds.
This method is the source of the concern. ISL mining involves drilling a pattern boreholes into the orebody, he explains. “In the centre of each pattern is a single abstraction borehole. The remaining boreholes forming the margin of the pattern are injection boreholes. A leach solution of groundwater and sulphuric acid, similar to battery acid, is pumped down into the orebody,” he says.
According to Uranium One, these wells are cased with PVC or HDPE piping that prevents the mining solution from contaminating rock or soil formations. They say the leach solution is a weak concentration acid of less than 2% of H2SO4, whereas true battery acid has about 30% to 50% of H2SO4.
The Russian uranium explorer is adamant that its planned surface plant will remove uranium and other heavy metals released through the leaching. “Uranium One will initially conduct a limited ISL test with maybe just a few wells, and the well field could be later enlarge after obtaining additional permits. During this test mining, Uranium One will show that groundwater in the wellfields can be efficiently purified and that any contamination will be contained,” the company said. Use of above-ground horizontal piping will allow for constant monitoring. Possible leaks from wells through cracked PVC casings can be avoided through regular casing integrity tests, they say.
In America ISL mines have to pump more solution from the wellfield than they inject, to create a hydraulic gradient forcing the groundwater to flow into the mining area and prevent water with uranium and acid leaving the mining area, the company explained.
Uranium One quotes ISR mine safery specialist Wayne Anderson who says: “ISR mining for uranium, when proper planning and management practices exist, will have limited and short-lived environmental impacts.” Each mining site related issues are unique, he says. “Examples certainly do exist of how ISR uranium mining has been successfully carried out over several decades in active agricultural settings. Cameco Corporation’s Crow Butte and Smith Ranch operations in the U.S. are two examples of such success,” he says.