Olympic Dam mine toasts 50 years as geologist Kathy Ehrig reflects on more than 30 years

Olympic Dam in the SA outback has been home to thousands of workers for generations and a major milestone this weekend has given mining giant BHP reason to celebrate.

The first thing Kathy Ehrig noticed when she stepped off the plane was the flies.

It was April 1, 1992 and the Californian-born Ehrig had just landed at Olympic Dam to start her new role as a research geologist.

She’s 34 years old and excited to have arrived at the one of the biggest metal producing deposits on the planet – an ore body to which she will dedicate her working life.

The flight from Adelaide has been on an 11-seat Metroliner, where the only type of in-flight service was an Esky getting passed up and down the aisle.

But still, she was up for an adventure and even the flies can’t deter her from falling in love with the place – so much so that today, more than 30 years later, she still works there.

Sure, she’s based at BHP’s Adelaide headquarters most of the time these days, but as the company’s superintendent geometallurgy, she still gets up to Olympic Dam, about 570km north of Adelaide, as much as she can.

BHP geologist Kathy Ehrig at the company’s Adelaide headquarters. Picture: Ben Clark

Dr Ehrig lived at Roxby Downs for 14 years and resisted moving south as long as she could, such was the attraction of the endless red-dirt horizons, breathtaking night skies and, of course, the people.

She’s speaking to The Advertiser to mark the 50th anniversary of the first exploratory drilling, in the winter of 1975, at the site of what had previously been a pastoral station.

“I loved living out there – you could go off and drive and do anything you wanted,” she says. “It was a smaller community, where everybody knew everybody

“I got invited, because I was a geologist, I got to know a lot of the station owners. So you really get to meet the bushies – it was a fantastic experience.”

These days, her BHP colleagues describe Dr Ehrig as a legend of the company that has employed countless thousands of people at the mine named after a dam dug out of a claypan in 1956. That dam was named after the Olympic Games taking place in Melbourne that same year.

Drilling at Olympic Dam in 1976.

It’s a mine which now provides employment to about 3500 workers, nearly half of the 8000 or so who work in BHP’s Copper SA enterprise at either Olympic Dam, Carrapateena, Prominent Hill or Adelaide.

And it’s a mine, one of Australia’s deepest, that boasts more than 700km of underground tunnels and produces nearly 900 tonnes of copper a day. It’s so big, Olympic Dam’s mine life is expected to be more than 100 years.

But when Dr Ehrig started working at Olympic Dam in 1992, the mine was owned by Western Mining Corporation and less than 1000 people worked on site.

She was one of few women to be in a role that was not in administration or cleaning but that didn’t stop her joining in with the weekend-long parties of the era and eventually become an Australia citizen.

She describes the dual purposes of her role as investigating how the ore body was formed and providing mineralogical support, ie analysing the internal structure of the ore, to the metallurgists charged with extracting metal from the earth.

The evolution of computers, AI and the internet has revolutionised the way she has worked over the past 30-odd years. Neither emails nor mobile phones had arrived at Olympic Dam when she started.

Shaft sinker Jusuf Vrbic, 39, drills a "pin hole" 360 metres down in the Whenan shaft at Olympic Dam in 1982. Picture: Peter Watkins

Now 67, she’s excited about the future of the mine, the second largest metalliferous deposit on the planet. Only Norilsk in Siberia is larger. Copper accounts for 60-70 per cent of mineral production at Olympic Dam, uranium 15-20 per cent, gold 10-15 per cent and silver the rest.

“It’s been here a long time and will be here a long time as other deposits come in and fade out,” Dr Ehrig says. “It’s significant to South Australia – the impact of mining in the state is a big deal.”

Apart from the thousands of jobs it has provided over the years, Olympic Dam has also been a massive source of royalties income for the state government. In the financial year ending June 30, 2024, BHP contributed nearly than $300 million to state coffers.

BHP Copper SA asset president Anna Wiley says Olympic Dam was extraordinary in both its scale and complexity.

“It is unique to South Australia and something we should all be proud of,” she says.

“Olympic Dam is one of the biggest deposits of mineral resources in the world, rich in copper, uranium, gold and silver, and it’s amazing to think that after 50 years of exploration we still haven’t found the bottom of it yet.

“The story of Olympic Dam’s discovery represents the very best qualities of ingenuity, perseverance and working together, which is worth reflecting on as we begin another chapter of copper production in South Australia.”

BHP superintendent of geometallurgy Kathy Ehrig.

KATHY ALMOST LITERALLY A GEM

BHP geologist Kathy Ehrig is part of an extremely exclusive club.

The 33-year Olympic Dam veteran is one of the very few people alive to have had a mineral named after her.

The International Mineralogical Association has officially recognised the new mineral Ehrigite in recognition of Dr Ehrig’s life’s work studying geology and geometallurgy.

Adelaide University professors Chistina Ciolanu and Nigel Cook discovered the mineral from samples unearthed in Canada, and spent a decade fighting to have it named after Dr Ehrig.

Ehrigite is a submicroscopic bismuth telluride mineral with a unique crystal structure and one of just 6100 officially recognised by the AMA.

Dr Ehrig, who shifted from her home state of California to start work at Olympic Dam in 1992, said it was an honour to be recognised in such a way.

BHP superintendent of geometallurgy Kathy Ehrig in 2016.

“I’ve been on the forefront of utilizing advances in technology and figuring out how we’re going to use that to actually help us understand what’s in the ground and then characterising the whole deposit – that’s been my speciality,” she said.

“I’m a scientist who happens to work in the mining industry. What’s good about working in the mining industry, number one, is usually no matter where you are, there’s always a mixed bag of disciplines together.

“We work together to achieve a common goal and you have to bring a lot of different people together to do that. And so that’s what’s fantastic and you do have the opportunities … like travelling around the world.

“Somebody pays me to walk around mountains … and then in a more modern sense pays me also to look down microscopes and to do all that stuff to be a scientist – it’s very cool.”