On a summer day in 1923, prospector John Campbell Miles stopped for smoko near a large outcrop on his journey through outback Queensland.
Carving a piece of rock from the formation, Mr Miles wrote in his travel notes that it "contained mineral, from its weight".
A year later, in January 1924, Mount Isa Mines was established to capitalise on the lead deposits Mr Miles had uncovered.
This week, 100 years after the company was formed, Mount Isa remains one of the richest mining regions in the world.
Experts reflect on how the curiosity of an adventurous prospector brought about social, economic and industrial development on a national and global scale.
Mining 'kindergarten'
It was not until the Townsville-Duchess rail line opened in 1931 that Mount Isa's population grew from 600 to more than 2,000.
"It became one of the largest employers in the country and was about the only place in Australia where people could earn a good living during the Great Depression," historian Barry Merrick said.
The mine's distance from ports and other cities meant its workforce had to be self-sufficient.
"People throughout the world considered Mount Isa Mines as the kindergarten, the training centre of mining," Mr Merrick said.
"If you were taught at Mount Isa Mines, you were seen as a skilled miner."
Railway of riches
The railway was opened in Mount Isa to transport ore to Townsville, but the financial benefits extended well beyond the local books.
"It was the first rail line in Queensland to generate revenue, so the money that came from the rail line actually helped fund all the other rail lines," Queensland Resources Council economic policy director Andrew Barger said.
"It also completely transformed Townsville … it enabled investment in that port.
"Then we saw the development of the smelters and the refineries and the workforce in Townsville."
Copper and culture
During World War II the government requested Mount Isa Mines start tapping into the region's vast copper reserves.
Today, Mount Isa Mines is the second largest producer of copper in Australia and is home to Australia's deepest copper mine, which runs to a depth of 1.9 kilometres underground.
It has produced enough copper to build more than 39 million houses and enough zinc to manufacture more than 535 million cars.
In 1949, there was a dramatic change to the cultural landscape of the community as war-weary Europeans flocked to Mount Isa to make their fortune at the mine.
As a result, there are now about 50 different nationalities that make up the city's population of about 20,000.
A pioneering mine
Innovation was the key to minimising costs and ensuring the viability of the mine in such an isolated location, Mr Merrick said.
In 1985, Mount Isa Mines, in partnership with Professor Graeme Jameson from the University of Newcastle, invented the Jameson Cell – a lower-cost form of flotation processing that produced a more concentrated ore.
Since then, 430 Jameson Cells have been installed in 30 countries, according to Glencore.
"The mine also developed its own smelter technology – a more efficient, cleaner way of producing copper in smelters – and they have sold that technology to other companies throughout the world," Mr Merrick said.
Mount Isa Mines is also host to one of the largest zinc mines in the world.
It contains an estimated 650 million tonnes of resources.
The end of an era
In October 2023 Glencore announced that it would be closing its copper operations in 2025, bringing an end to one of the largest mining projects in the region.
Chief operating officer for Glencore Australia's zinc assets, Samuel Strohmayr, said the company was "actively seeking new opportunities" in the region while committing to its George Fisher zinc mine going forward.
"We certainly have on our books long-life assets that we will continue to develop and invest in in this region."
"One hundred years of mining is an absolutely brilliant achievement," Mr Merrick said.
"II think our city should be really proud and look forward to an interesting future ahead."