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Posted 02.24.11 | PERMALINK | ESSAY

In addition to contaminated groundwater, one of the most severe environmental dangers at a regional scale is Acid Mine Drainage (AMD), produced by naturally occurring sulfuric compounds in the earth that are exposed to oxidation during mining and dissolved in water. The heavy metals in AMD are harmful to humans and the ecosystem. Since deep shaft mining has ceased, it is no longer financially viable for mining companies to continue to maintain low water tables in the mines. As a result, the groundwater table rises at one meter per day, submerging abandoned shafts and tunnels in the Johannesburg area. At this rate, experts estimate that AMD will begin to surface in Johannesburg in 2012, threatening the drinking water of the entire urban region and even communities downstream in the major international watersheds of the Orange and Limpopo Rivers. Mining companies in the Witwatersrand have formed an alliance, the Western Utilities Corporation, to propose solutions to treat AMD at a regional scale. [Photo by Dorothy Tang]

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