The Mponeng gold mine in Carletonville, Gauteng, was AngloGold Ashanti's only South African underground mine. Picture: BUSINESS DAY
The Mponeng gold mine in Carletonville, Gauteng, was AngloGold Ashanti's only South African underground mine. Picture: BUSINESS DAY

On the eve of AngloGold Ashanti's exit from SA mining, three miners were killed in an earth tremor at its Mponeng operation, the world’s deepest mine, underscoring its decision to focus on shallower mines around the world.

A level 2 magnitude tremor at midday on Thursday initially trapped seven miners 3.5km below ground at the mine west of Johannesburg and near the town of Carletonville. Four were quickly rescued, some with broken limbs but no life-threatening injuries.

Specialist rescue teams, known as proto teams, searched for the three miners during the afternoon and through the night.

“The bodies of our three colleagues have now been found. Two of these bodies have ... been recovered and are being brought to surface by rescue crews. The third body is currently being recovered,” AngloGold said on Friday afternoon.

All work, apart from essential services, has been stopped at the mine.

The mine had a stellar safety record up to Thursday, recording 698 days of operations without a fatality, a remarkable achievement at such a deep-level mine in an area that is seismically active.

The mine, which employs 5,000 people, sends 3,000 people underground during peak mining times every day. It had notched up 2.35-million fatality-free shifts by Thursday.

While a level 2 earthquake is barely noticeable on the surface, at 3.5km underground where rock is under tremendous pressure the consequences are potentially severe. In this case, it led to an incident the industry calls a “fall of ground”. It means rock has either dropped from the top of tunnels and working areas or burst out from the side walls.

In this instance, AngloGold believes the tremor happened in front of the working area, in rock that was yet to be mined, releasing a surge of energy.

SA’s gold mines had for decades been dangerous places to work, with annual fatalities running into multiple hundreds. The department of mineral resources & energy (DMRE) says 11,000 miners died between 1984 and 2005.

In 2019, the number was 51 — the lowest on record, according to mineral resources & energy minister Gwede Mantashe — down from 81 the year before, with the gold industry reporting the largest decrease, dropping to 19 from 40.

The Association of Mineworkers and Construction Union (Amcu) said on Friday morning companies should invest more in “safety systems and infrastructure”.

“Mining houses should face greater accountability through stronger regulation and enforcement by the DMRE,” it said.

AngloGold in February agreed to a R4,7bn ($300m) sale of Mponeng, a 4km-deep mine, by far the deepest in the world, its Mine Waste Solutions tailings retreatment business and two mothballed mines to Harmony.

The portfolio is changing. When we sell the SA assets, that’s the last ultra-deep, hard-rock underground mine. We move to shallower underground and open pit production. That’s an important transformation,” AngloGold CEO Kelvin Dushnisky said in February.

Harmony will pay AngloGold $200m in cash and $260/oz of gold from Mponeng and other underground assets included in the transaction based on production above 250,000oz a year. These payments would be made for six years from the start of 2021 and are capped at $100m.

Harmony will pay a further $20/oz on gold output coming from any extensions of mining below existing infrastructure at the three mines included in the transaction, Mponeng, Savuka and TauTona.

Mponeng has 8.5-million ounces of gold reserves in a planned extension to the mine that would take its life to 20 years.

seccombea@businesslive.co.za

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