Ed Stoddard

AngloGold Ashanti aims to use new technology to go 5km below the surface to reach 70 million ounces of gold.

The drive to reach a resource worth $125 billion (R928bn) would see blasting eliminated and remove humans from the stopes where gold was extracted, Mike MacFarlane, AngloGold’s senior vice-president for technology, told a mining automation conference yesterday.

“Gold production is in decline. Our aim is to arrest that decline or even increase production,” he said.

“We are standing on the edge of a major shift in the way people think about underground mining. And it’s a shift that you see just once in a 30- to 40-year timeframe,” he said.

AngloGold operates the world’s deepest mines; its Mponeng operation is about 4km deep. But MacFarlane said tens of millions of ounces could not be reached and so the ore “was not making any money and there is no pull for investment”.

With safety a huge concern as South African gold producers goes deeper, MacFarlane said AngloGold was aiming to “remove people from high risk activities… The driver of this project has been safety.”

Machines would mechanically cut the rock so workers could be removed from the narrow passages known as stopes, where a lot of fatalities happen.

“We would like in three to five years to have a working model underground where we can start the transition to bring this non-blasting approach across our entire operations.”

Such changes would enable the company to increase its extraction rates from around 8g a ton to 16g or more. This is because the stopes are 1.5m high to fit a human, while the ore body is about 60cm wide.

Gold’s record run has sparked a wave of research and development activity. Such technology may be needed to go safely to new depths but it could also cost jobs.

source:business report