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Lined Tailings Facilities - Consequential Risks Require Better Understanding

Publication: Mining Review Africa
Issue: October 2018

The mining industry in South Africa – which extends back more than a century – is grappling with historical legacies that have been put under the spotlight as the world becomes more environmentally conscious and responsible. Tailings management in particular, an area neglected in the past, is now a priority. While lining have become the preferred option to reduce possible environmental impact of tailings material they pose their own set of risks which urgently need to be monitored and addressed, Knight Piésold technical director for mining Andrew Copeland tells Laura Cornish.

Up until a few years ago, the mining industry in South Africa took a reactive approach to environmental impacts caused by mining activities. Unfortunately, tailings-related impacts are severe – and can result in loss of life, long-term damage to the environment and ground water pollution.

“The combination of legislation covered by the National Environmental Management: Waste Act, 2008, and Government Notice 332, May 2014 in which residue deposits were deemed as a waste unless de-classified or exempted by the minister, has seen the mining industry’s determination to make amends by complying. Together with government, consultants such as ourselves are working closely with the sector to improve our environmental image,” Copeland starts.

The mines have subsequently turned primarily to linings as a means to ensure seepage from tailings deposits does not come into contact with the natural environment. The government has also shown favour for this route as it considers it a proactive and trusted mechanism which guarantees protection of the environment.

“It is commendable that our industry is embracing the need to reduce its impact on the environment and we are undoubtedly heading in the right direction but few are aware that the solution we are now deploying has its own potential risks,” Copeland reveals.

The incorporation of linings for example is not a finite solution. Like most plastic-based products, they degrade over time (20–100 years possibly, depending on the quality of the lining and the material it houses) and will leak. This means they cannot be considered a long-term option on their own, and may only function well during the operational life of the tailings facility.

But there is a far greater risk at play, Copeland highlights. “The incorporation of a lining, be it traditional synthetic material the clean-up), there is the cost of having to prematurely build new facilities, an equally disastrous reality for the industry. “Considering that South Africa’s lined tailings facilities are <5 years in age, we are in a period of beginning to understand whether such designs are sustainable and if/when we reach the crossroad of having to build new tailings facilities to replace unsafe ones.”

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