Gold tailings and hard rock miner Mintails is set to boost its production capacity by the end of the year following the regeneration of its flagship Mogale Gold plants ono South Africa’s West Rand.
Not only does the Australian-listed firm aim to become the country’s second-largest tailings miner within five years, but also to greatly increase its underground and hard rock activities, signalled by the recent opening of its D-shaft asset.
In achieving this expansion the challenge of regenerating old underground basins comes to the fore, with the company carrying out vital de-watering work which will not only allow it to mine the freed-up gold but also pass on revived land post-closure to help address a chronic housing shortfall.
Mogale Gold
The extraction of minerals from ore requires that the ore be ground into fine particles, so tailings are typically small and range from the size of a grain of sand to a few micrometres and are usually produced from mills in slurry form.
On completion in September-October this year, the Mogale site will be able to treat six million tonnes of tailings slime, sand and hard rock.
General Manager of Operations Jan Jacobs added: “The re-opening of the second Mogale plant will take capacity up by 400,000 tonnes to over half a million tonnes a month. This is not our only development, but is by far the biggest ongoing project.”
The company, set up in 2005, acquired the Mogale site in 2006 which saw it taken out of government control. In total it controls around 106 million tonnes of tailings resources.
Going underground
Alongside its continuing open-pit operations, Mintails is targeting significant growth underground and opened its D-shaft asset in February this year, producing around 5,000 tonnes a month.
“This project is a demonstration of principle rather than sheer volume,” Jacobs said. “It shows that underground mining here is possible and a viable thing to do, as we project all-in costs of around $800 per ounce which is extremely cheap. We are targeting blocks left behind by previous miners in the 1950s.”
“This will be a big focus for us, moving from open-cast mining to significant tonnes of underground production, around 1.5 million over the next five years.”
But for the company to be successful underground it must decant the target basins and bring the water level down from its current level of around 60 metres to an eventual target of 500 metres. It is working closely with the government on the first step of getting the water down to the environmentally critical level of 160 metres.
Such a task requires enormous commitment. Jacobs added: “It’s not just the pumping cost, it’s the fact it is dilute sulphuric acid and treatment of this is very expensive. Any discharge must be at an environmentally sensitive level and have patented our own process for this.”
Mintails has managed to reduce the cost of treatment from R8 per cubic metre, about the cost of drinking water, to a much more viable R3.
It is also working closely with South African universities to bring the water quality up to a level where it can be used in applications beyond discharge back into the environment.
Rescuing land
Not only will clearing basins of acidic water enable further mining activity, it will also revive degraded land to a safe level for the construction of housing, something which is desperately needed in the Johannesburg hinterland.
It is already recovering land through open cast mining by removing the on-surface reef outcrops and stabilising the area, and post-closure operations will become a top priority for the company.
“Although mining has taken place here for the last 120 years no single gold mine has achieved closure of mines, it has always been signed back,” Jacobs said. “We want to be the first ones to close mines.
“Environmentally, the West Rand is among the worst. In the late 1990s all mining slowed down, all pumping stopped, all maintenance stopped and land sat there to degrade for 10 years. We need to leave it in a state that is useful again.
“Unfortunately due to a chronic shortage there are a lot of informal settlements popping up and these people are living in areas of high environmental degradation.”
Mintails aims to release 8,000 hectares of land for settlements having alleviated around 600 to date. The programme is made up of a 20-year plan with the company board comprising of considerable expertise in the property market, a key area for the business post-closure.
“This won’t be a quick fix,” Jacobs added. “De-watering is a short term solution and we have to stop it filling up again. We need to bring benefits to the society we operate in while still giving shareholder value and we’re doing this at present.”
Hands on
Ensuring Mintails continues to excel above and below ground on these important works is its 250 employees and further 550 contracted workers, all from local communities. This is set to rise to more than 3,500 as underground operations pick up.
Training is thus a huge priority, and the company runs its own hands-on training shaft, giving workers first-hand experience of the vital skills required as well as a practical approach to safety rather than the typically bureaucratic style seen in bigger mining houses. It has not suffered a fatality since it began in 2005.
It is also compliant with Black Economic Empowerment (BEE) regulations through a wholly meritocratic attitude to employment, making this legal must an irrelevancy when coming to hire the best available.
“These people are partners, not BEE partners,” Jacobs said. “A lot of companies have made mistakes in pushing the BEE numbers for the sake of complying with the rules.”
With the best on board Mintails can complete its short term goal of becoming the second-largest tailings miner in South Africa while looking ahead to effective longer-term strategies post-closure, ultimately becoming a key partner in the battle to address the national housing shortfall.