Waterfall flows again after 50 years
The Hlobane waterfall near Vryheid in KwaZulu-Natal is flowing again after more than 50 years, Kumba Resources said on Monday.
The waterfall stopped flowing decades ago due to mining activity at the underground Hlobane colliery, which Iscor Mining (now Kumba Resources) purchased from Gencor in 1983.
Cracks up to 2m wide developed on Hlobane mountain due to underground mining activity that started more than 100 years ago.
Rain that mingled with water run-off from Hlobane mountain became contaminated after seeping into the cracks and through three coal seams before decanting into nearby water catchments. With that, the waterfall stopped flowing—until now.
Kumba closed the Hlobane mine nearly five years ago and contracted its wholly owned subsidiary Ferroland to come up with a solution that would minimise mine-related water pollution.
Ferroland opted for a more complex solution that had never been attempted before: to plug the cracks with a sealing liner painted with bitumen, and underlined with a mixture of available soil and bentonite clay.
This seal had to be flexible, durable and non-toxic.
The bitumen film is of a non-toxic nature and bentonite is a naturally occurring substance. The seal was then covered with rocks and soil and was vegetated to prevent it being washed away.
“This is the first time this kind of project has been successfully carried out anywhere in the world,” says Ferroland managing director Robert Brownlee.
“What is unique about it is the fact that it is part of an integrated water management system. We have already sealed about 1km of cracks over an area covering about 1200ha, and even though we are not yet finished, the Hlobane waterfall is once again flowing—despite the poor rains we’ve had this year.”—Sapa