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Does new technology offer rich, long-life for SA’s ultradeep mines?
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24th May 2013
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South African technology, the nomenclature AngloGold Ashanti has chosen for its modern new “game-changing” mechanical-cutting mining application, has passed the test at the company’s TauTona pilot site.

The cautious optimism that AngloGold executives were applying to comments on this new automated technology – which stops all blasting, creates peopleless stopes and allows year-round, around-the-clock continuous mining that puts the focus back on to revenue – is now giving way to far more confident rhetoric.

“This is a game changer for all the mines with similar orebodies to ours,” AngloGold Ashanti executive director Tony O’Neill told fund managers, analysts and journalists at this month’s presentation of sixfold-better company results.

What is being coordinated into a fully fledged system extracts the ore and only the ore and eliminates the dilution curse.

Since early 2010, each AngloGold Ashanti update has been better than the last, to a point of the latest announcement of the technology now being accelerated “aggressively” towards commercial application.

The pilot site at the TauTona gold mine, west of Johannesburg near the town of Carletonville, has yielded encouraging gold tonnages, which is why the technology is being migrated to other AngloGold Ashanti sites with suitable orebodies.

“There’s been very good progress made in the last six months,” O’Neill said of the work being led by AngloGold Ashanti executive VP for South Africa region Mike O’Hare and AngloGold Ashanti VP for technology Shaun Newberry.

Flashed up on the big screen during the results presentation was news of four additional 30-m-long holes being success fully completed in the first quarter of this year. The quarter also saw greater system efficiency slip 25% off the time it took to drill the 30 m holes.

The design of the first production machine is under way and two of the long holes have been successfully filled with ultra-high-strength backfill that “proves the viability of this technology”.

New AngloGold Ashanti CEO Srinivasan Venkatakrishnan (Venkat) told Mining Weekly that he was totally committed to the South African technology project.

“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,” Venkat said, adding that its implementation may add another 30-million ounces to AngloGold Ashanti’s South African reserves.

“It could double our South African reserve base,” he added.

The head of the JSE- and NYSE-listed gold major encouraged members of the media to take a trip to see the working faces at the TauTona mine at first hand.

“It’s actually produced very good results. We’re able to get a good tonnage of gold from the areas where we’re 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,” says Venkat.

The company has spent $30-million to $40-million on the new nonblast technology that leapfrogs mechanisation into automation, and enables ultradeep mining to take place safely.

Venkat promised regular progress reports at future results presentations.

AngloGold Ashanti executive VP Mike MacFarlane, who has played a leading role, told the Investing in African Mining Indaba in Cape Town, in February, that the technology was providing access to “mouth-watering” 25 g/t grades from depths of 5 km-plus.

Without having to invest in new infrastructure, mining could be done in a fifth of the time.

Current mining practice is considered wasteful, not only because it sterilises too much gold in the ground, but too few days are worked.

Global competitors mine 365 days a year with 5% to 10% dilution, compared with South Africa’s 274 working days and high dilution.

Also, too little time can be spent at the face because of the long travel time to the face as mines deepen.

CONVENTIONALLY IMPOSSIBLE

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.

Getting it right will change the mining paradigm for deep hard-rock underground mines globally.

The tunnel boring that has been under-taken sextuples the pace of development to 20 m a day from 3 m a day, while ultrahigh-strength backfill dispenses with the need to leave large support pillar areas unmined for safety.

It was calculated that more than 40% of the gold was being left behind in shaft pillars, which the new technology allows to be released, and 200% dilution eliminated, by extracting ore only.

While South African mining has, by and large, not participated in the mechanised mining era, which has been widespread since the seventies, the new technology allows the South African industry to leap from the current manual era directly into automation.

Mine design is tailored to suit the technology and not the technology to suit mine design.

Core competences have been redefined and new sets of skills learnt on a foundation of safety, a real-time single information source, reduced energy and automation.

South Africa has slipped from being the world’s number one gold producer to being number four behind China, Australia and the US, and platinum mining is in need of dramatic cost reduction.

Without new technology, millions of ounces of precious metals would be lost to the economy.

The outcome of this work is probably not going to be implemented in all AngloGold Ashanti’s South African mines, but it makes sense to do so where it opens up new reserves.

Edited by: Creamer Media Reporter

 

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