JOHANNESBURG (miningweekly.com) – New mining technology, which has already been so successful on one site that it is being migrated to others, could be a key game changer for the South African mining industry.
New AngloGold Ashanti CEO Srinivasan Venkatakrishnan (Venkat) said he was totally committed to the South African technology project, which had been piloted with impressive results at AngloGold Ashanti’s Tau Tona gold mine, west of Johannesburg near the town of Carletonville.
AngloGold Ashanti executive director Tony O’Neill said not only gold mining, but also platinum mining, potentially stood to benefit from the new technology, which stops all blasting, creates peopleless stopes, allows year-round mining around the clock and refocus on revenue.
“There’s been very good progress made in the last six months,” O’Neill said.
The progress had been in drilling and backfilling, and the challenge now was to take all of the technology’s independent activities and “aggressively” unite them into a consolidated system so that it could be employed in production forecasts going forward.
Venkat said the sceptics were being proved wrong.
“A number of people were sceptical about the ability of technology to improve the long-term viability of the South African mines and we have started to prove them wrong,” he added.
The head of the JSE- and NYSE-listed gold major encouraged members of the media to examine the Tau Tona working faces first hand.
“That was our pilot site. It’s actually produced very good results,” he said, adding that the technology was now being migrated to additional sites.
“We’re able to get a good tonnage of gold from the areas where we are using the new technology and we’re currently expanding the technology to other areas within the South African mines.
“We believe getting that right is not just going to benefit AngloGold Ashanti in the future, but it is going to benefit the mining industry generally and, importantly, provide employment for longer for our South African workforce,” he said.
“It’s not a big amount that we’re spending,” Venkat added to Mining Weekly Online.
The company has spent $30-million to $40-million on the new nonblast technology that leapfrogs mechanisation into automation, and enables mining to take place safely at ultra-deep levels.
The technology could potentially add another 30-million ounces to AngloGold Ashanti’s South African reserve base.
Progress reports on the technology would be given regularly at results presentations.
AngloGold Ashanti executive VP Mike MacFarlane told the Investing in African Mining Indaba in Cape Town, in February, that "mouth-watering grades" of 25 g/t would be recoverable from depths of 5 km and more using the technology, which allowed mining to be done in a fifth of the time, without any need to invest in new infrastructure.
The project got under way in 2010 with the aim of unlocking 100-million ounces of gold that could not be mined conventionally.
It was not a question of having invented anything, but rather of putting existing technology together in creative ways, he added.
“We could be turning what appears to be a sunset industry into a sunrise industry. We believe that if we get this right, we could actually change the mining paradigm for deep hard-rock underground mines globally,” MacFarlane said.
The tunnel boring that had been undertaken indicated that it could increase the pace of development from 3 m a day to 20 m a day, and ultrahigh-strength backfill now being used would dispense with the need to leave large pillar areas unmined in order to assure safety.
South Africa still has one of the biggest gold resources in the world, but that gold is at depth, which results in significant amounts of the precious metal having to be left in shaft pillars and stability pillars, because blasting upsets the ground conditions and creates seismicity.
The proposed new way of mining dispenses with blasting, keeps people away from the danger areas, facilitates mining round-the-clock every day of the year and refocuses on revenue.
Current wasteful mining practise is not considered sustainable, not only because it sterilises too much gold in the ground, but also because South Africa is not competitive with its peers in term of days worked and time spent at the face.
Global competitors mine 365 days a year and at only 5% to 10% dilution, compared with only 274 working days and high dilution in South Africa.
Greater depth also adds to travel time, which means that mineworkers in many deep South African gold mines end up spending too few hours at the face.