The government will impose an environmental levy on mining companies, the proceeds of which will go towards the R12-billion needed to treat Gauteng's acid mine water. Minister of Water and Sanitation Nomvula Mokonyane yesterday confirmed that mining companies, among others, would carry 67% - or just under R8.4-billion - of the cost of treating acid mine water that would eventually be used by industry and homes.End-users of the final product, including millions of residents, will pay the remaining 33% of the cost, or about R3.6-billion, which will be recovered through water tariffs.Mokonyane was speaking at the Wits central basin acid mine drainage treatment plant in Germiston, on the East Rand.A similar plant has been set up on the West Rand and a third, in the eastern part of the basin, is due for completion soon. Mokonyane said the three treatment plants would cost R25-million a month in total to run.Earlier this month, The Times reported that the cost of treating acid mine drainage had been estimated at R10-billion, with residents of most Gauteng municipalities having to carry a third of that cost.The level of underground acid water is rising, threatening to contaminate sources of clean water. Many of the mines from which the water is seeping have long been closed or have changed hands , leaving the government stuck with the problem.It remains to be seen whether the mining companies will agree to be subjected to the levy.The dangers of acid mine drainage were first identified in the early 1900s.Mokonyane yesterday repeatedly assured the public that several mining houses had shown "great enthusiasm" in working with her department to solve the funding issue."If we had not intervened, the flow of acid mine drainage into the larger environment, including the natural river systems, would have caused widespread environmental pollution."She said the state was not adopting a punitive approach and the measures taken to curb acid mine drainage would not be applied retrospectively - meaning that extant mining companies whose activities led to polluted mine water will not be made to pay part of the cost of treating acid mine drainage.The revelation that Gauteng residents would have to carry some of the cost emerged during a meeting of the environment and infrastructure services committee of the City of Johannesburg on April 12...