Modern Mining December 2022

(Image courtesy of Mark Olalde)

Abandoned and liquidated mines According to Liefferink, industry currently sits with a number of liquidated mines, including some located within the Witwatersrand gold fields, such as the Mintails Group of Companies (Mintails Gold, Mintails SA, Mintails SA Randfontein Cluster), Shiva Mine, the Blyvooruitzicht Gold Mining Company and Central Rand Gold, Grootvlei Mine. “These liquidated mines,” Liefferink explains, “are often abandoned with no mitigation or management measures implemented such as dust control, storm water management control, functioning penstocks, piezometers and toe paddocks, erosion control, slope stability control and no access control”.

collapsed infrastructure and other hazards, such as contaminated water and soil, chemicals and metals, radioactivity, windblown dust and, in the case of coal mines, spontaneous combustion of coal and coal residue. In the Jagersfontein tragedy, the cause of the TSF’s failure is described as a “structural failure”, but reasons for failures can include seismic instability or earthquakes, external erosion, seepage and internal erosion, slope instability, overtopping and structural inadequacies. Aside from the health and safety risks, these abandoned mines have also given rise to a prolifera tion of illegal mining and criminal syndicates.

Shacks built on top of a gold mine tailings pile on the East Rand.

Abandoned mines have considerable negative impacts on the health and safety of local communities and on the environment.

“It must be remembered’: says Liefferink, “that tailings dams are living structures and require in-depth understanding and continual management within an appro priate tailings management system. To manage mining facilities responsibly, TSF owners must understand the physical and chemical risks associated with the TSF and implement controls to reduce risks relating to potential health, safety, environmental, societal, business and economic impacts during the life of mine, including closure and post closure. “If poorly designed, constructed or man aged, tailings storage facilities represent a significant risk to local communities and ecosystems, especially in downstream environments. In South Africa most of our facilities are upstream facilities, which are low cost but high risk.

December 2022  MODERN MINING  27

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