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Unlocking social and environmental benefits through tailings retreatment Mining Weekly Audio Articles
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The retreatment, or remining, of mine tailings can provide usable land, provide profits for companies and clean the environment by moving the reprocessed tailings to more advanced and well-managed facilities.
Owing to changes in legislation, tailings need to be stored in facilities that are better managed and controlled than historical facilities. This means that the tailings from remined sites are sent to new tailing storage facilities (TSFs), said specialist consulting engineering firm Jones & Wagener environmental engineering closure and rehabilitation associate civil engineer Alice Harvey.
"Typically, existing tailings are present in smaller facilities, but are being sent to be managed more centrally in larger facilities. Processes have changed, stability assessments have improved significantly and facilities are required to be aligned to certain standards to have a much lower, or no, impact on water quality, compared to the historical facilities," she said.
The tailings facilities or mine dumps that have not been rehabilitated still have existing safety risks and environmental impacts that are not being managed. However, if these facilities and dumps are seen as a resource and remined, then there is more control over and management of the risks, she noted.
There are about 6 000 unrehabilitated, dormant or abandoned mining dumps and tailings facilities in South Africa, and about 337 of them are at high risk and need immediate attention, said Southern African Institute of Mining and Metallurgy tailings committee member, hydrogeologist and mine water strategist Dr Kym Morton.
In the industry, mining houses are finding that increasing their efforts in managing their TSFs and retreatment of tailings is an opportunity to improve their social licence.
People in South Africa are familiar with seeing mine dumps daily, especially in Johannesburg, Welkom and along the Witwatersrand belt. There are massive opportunities for South Africa in the way it manages active and abandoned TSFs, including for the minerals in them and potentially to use the materials as building materials, she said.
JSE-listed gold miner DRDGold is processing about 500 000 tonnes a month from one site and recovering about 30 kg of gold. This gives an indication of the throughput that must be maintained to have a financially viable model, highlighted DRDGold CEO Niël Pretorius.
Tailings from multiple smaller sites, usually tens of kilometres apart, need to be transported, processed and then moved to a central tailings site. These operations typically require liquefying the tailings, pumping them and then dewatering them again. Therefore, partner companies are usually involved and a holistic approach to designing the flowsheet must be taken, said minerals and mining engineering company Weir Minerals tailings and backfill global manager Erik Vlot.
No materials that DRDGold reclaims in the Johannesburg area and West Rand are sent back to their original sites where they were reclaimed from. The materials, once processed, are sent to a large central facility, where they are managed to a stricter set of health and environmental standards than when the tailings sites were initially established, said Pretorius.
"South Africa has about 120 years of tailings accumulation on the surface in a small area. Once there is a resource of adequate size, then it is a matter of setting up the technology and logistical infrastructure in such a way that you can process at the requisite throughput rate," he said.
Healthy Land
But, while operations must be commercially viable, remining and storing tailings more securely is a long-term sustainability game of incrementally creating an environment that is healthier and more pleasant to live in and near, Pretorius said.
Either remining and rehabilitating sites, or rehabilitating sites in situ can provide footprints of land that can be used for alternative applications, said Harvey.
"A contaminated land assessment needs to be done to unde
The retreatment, or remining, of mine tailings can provide usable land, provide profits for companies and clean the environment by moving the reprocessed tailings to more advanced and well-managed facilities.
Owing to changes in legislation, tailings need to be stored in facilities that are better managed and controlled than historical facilities. This means that the tailings from remined sites are sent to new tailing storage facilities (TSFs), said specialist consulting engineering firm Jones & Wagener environmental engineering closure and rehabilitation associate civil engineer Alice Harvey.
"Typically, existing tailings are present in smaller facilities, but are being sent to be managed more centrally in larger facilities. Processes have changed, stability assessments have improved significantly and facilities are required to be aligned to certain standards to have a much lower, or no, impact on water quality, compared to the historical facilities," she said.
The tailings facilities or mine dumps that have not been rehabilitated still have existing safety risks and environmental impacts that are not being managed. However, if these facilities and dumps are seen as a resource and remined, then there is more control over and management of the risks, she noted.
There are about 6 000 unrehabilitated, dormant or abandoned mining dumps and tailings facilities in South Africa, and about 337 of them are at high risk and need immediate attention, said Southern African Institute of Mining and Metallurgy tailings committee member, hydrogeologist and mine water strategist Dr Kym Morton.
In the industry, mining houses are finding that increasing their efforts in managing their TSFs and retreatment of tailings is an opportunity to improve their social licence.
People in South Africa are familiar with seeing mine dumps daily, especially in Johannesburg, Welkom and along the Witwatersrand belt. There are massive opportunities for South Africa in the way it manages active and abandoned TSFs, including for the minerals in them and potentially to use the materials as building materials, she said.
JSE-listed gold miner DRDGold is processing about 500 000 tonnes a month from one site and recovering about 30 kg of gold. This gives an indication of the throughput that must be maintained to have a financially viable model, highlighted DRDGold CEO Niël Pretorius.
Tailings from multiple smaller sites, usually tens of kilometres apart, need to be transported, processed and then moved to a central tailings site. These operations typically require liquefying the tailings, pumping them and then dewatering them again. Therefore, partner companies are usually involved and a holistic approach to designing the flowsheet must be taken, said minerals and mining engineering company Weir Minerals tailings and backfill global manager Erik Vlot.
No materials that DRDGold reclaims in the Johannesburg area and West Rand are sent back to their original sites where they were reclaimed from. The materials, once processed, are sent to a large central facility, where they are managed to a stricter set of health and environmental standards than when the tailings sites were initially established, said Pretorius.
"South Africa has about 120 years of tailings accumulation on the surface in a small area. Once there is a resource of adequate size, then it is a matter of setting up the technology and logistical infrastructure in such a way that you can process at the requisite throughput rate," he said.
Healthy Land
But, while operations must be commercially viable, remining and storing tailings more securely is a long-term sustainability game of incrementally creating an environment that is healthier and more pleasant to live in and near, Pretorius said.
Either remining and rehabilitating sites, or rehabilitating sites in situ can provide footprints of land that can be used for alternative applications, said Harvey.
"A contaminated land assessment needs to be done to unde
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