But her spokesman, Mlimandlela Ndamase, said the findings of the feasibility study - which recommended the desalination, at R8 billion, of the toxic water seeping from mine voids in the Witwatersrand mining basins - was "not the beginning and end of science" on the problem.
"The government must satisfy itself it has pursued the best, most cost-effective means to begin to resolve the AMD problem in the long term." Mariette Liefferink, the chief executive of the Federation for a Sustainable Environment, who sat on the committee overseeing the feasibility) study, said officials were pressured to fast-track the report's finalisation before its completion in June 2013.
"The report was submitted to the outgoing minister (Edna Molewa) and the current minister ... but it has not been signed off."
It found the failure to establish a sustainable long-term solution, or desalination, of AMD would lead to: the prolonged reliance on funding from the general fiscus; an increase in the salt load in the Vaal River, which could be mitigated only by releases from the Vaal Dam; and a subsequent deficit in the Upper Vaal that could have severe economic effects during a drought.
"We're using expensive water from Lesotho to dilute the high salt loads of the AMD," Liefferink said.
"It's nonsensical. It seems the minister is concentrating on the trivial, such as closing taps when you brush your teeth and putting bricks in your toilet cistern - but passing over this issue, which is of appreciable magnitude."
Ndamase said this was disingenuous.
"These are practical examples of how the government is trying to encourage South Africans to be water-wise.It is not a problem created by the government. It's highly complex.
"What you don't want is to go on an uninformed exercise where you begin to throw money at problems."
The report's motivation for desalination was that AMD contained a high concentration of salts.
The immediate treatment, or neutralisation, of AMD, a process that was under way, finished with water that contained sulphate levels of between 2500mg to a litre and 3000mg/litre, said Liefferink.The regulatory limit for drinking water was 200mg/l. Sulphate concentrations of 600mg/l and more caused diarrhoea in most individuals. Every day, 73million litres of water with these high suF phate levels were being released by the Central Rand neutralisation plant into the Vaal River. Thirty million litres a day were entering the Crocodile West.
"When the Eastern Basin's treatment plant is completed, another 100 million litres a day of highly saline water will be released into the Vaal River system," Liefferink said.
"Expensive water from the Lesotho Highlands Phase 1 (Katze Dam) is (being) used to dilute the high salinity in the Vaal River system."
Ndamase said Mokonyane would pronounce on the longterm solution in two months. "We can't deal with this piecemeal ... The minister has to consider policy ... and be prudent with the resources allocated to the department."