Dylan Langridge and Trevor Davis were operating a utility vehicle about 125 metres below surface in the Dugald River zinc mine in north-west Queensland on Wednesday morning.
At about 8:45am, an emergency alert was triggered after the pair plummeted into a void when the ground beneath them gave way.
On Thursday afternoon, the bodies of the men, both in their thirties, were retrieved.
The incident has cast a spotlight on safety standards in the Queensland mining industry.
Several experts say safety processes are not up to scratch and the sector faces several challenges before it can ever ensure a zero-casualty workforce.
The statistics
After Western Australia, Queensland is the second biggest mining state in the country.
Over the 141 years, from 1882 to the start of 2023, there have been 441 deaths in Queensland's coal mining sector, while 1,065 people have died in the mineral mining and quarrying sector, according to Resources Safety & Health Queensland (RSQH).
Since 2015, 14 people have died in the state's coal mining industry and nine lives have been lost to the mineral and quarrying sector.
Mining expert and University of Queensland professor David Cliff says any fatality is "too much".
"Mining is an industry which historically has high risks, but it is also an industry Australia has invested heavily in with technology and systems and risk management," he said.
How does safety work at a mine?
Mine safety standards and procedures are regulated by each state and territory.
In Queensland, the Mining and Quarrying Safety and Health Act 1999, the Coal Mining Safety and Health Act 1999, the Explosives Act 1999 and the Petroleum and Gas (Production and Safety) Act 2004, are the main pieces of state legislation.
Resources Safety and Health Queensland is an independent body that enforces the state legislation through its mining inspectorates that visit mine sites.
The Dugald River mine site had undergone 27 visits for audits and safety checks in the past two years, according to Queensland Minister for Resources, Scott Stewart.
Professor Cliff said most safety standards at a Queensland mine would involve operational safety and staff training.
"Safety is managed through a system of processes and operations," he said.
"That would delineate things like responsibility, levels of training required, and safety processes for the tasks carried out on the mine.
"Principal hazards like those involved on the ground would be assessed and then controls are developed to manage those risks," he said.
Focus on mass casualties needs to shift to individuals
Emeritus Professor Michael Quinlan, from the University of New South Wales' Industrial Relations Research Centre, has researched mine deaths around the world.
"Overall, the mining industry in Australia has a fairly good safety record," he said.
"But we can still improve further."
He said there were a major set of interventions carried out in the 1990s after mine disasters in NSW and Queensland.
"It brought a more systematic approach to health and safety … so principal hazard management plans and things like that."
He said it triggered mines to focus on reducing risks that impacted larger groups of workers.
"There were some major changes, but they were primarily aimed at dealing with multiple fatalities.
"They certainly worked, with the exception of [the Grosvenor mine explosion in 2020 that seriously injured five miners]."
But he said the industry now needed to take the same focus it had in the 90s to mass fatalities, and apply it to single or double fatality incidents.
Technology a double-edged sword
While technology had come to play a vital role in improving safety processes, it also posed a major challenge, Professor Cliff said.
"Modern technology has led to bigger, more complex mining — there are deeper and higher production rates, mining is more automated, more mechanical.
"And with that, comes new risks."
He said the number of people making up the mining workforce was getting lower as technology replaced manpower.
"That means there are fewer people around to keep an eye on things so there is now a challenge of making sure operations are properly covered," he said.
"The mining industry is in a state of complexity."
Staff training, complacency a challenge
Dr Elise Crawford, a workplace health and safety expert at CQ University in Rockhampton, said a lack of staff training and poor inter-departmental communication at a mine could result in risk-taking.
"[Workers] are not always aware of the hazards," she said.
"They just know if they do the job this way [and follow procedures] it'll be safe.
"When work is prescribed and has to be done a particular way and the people who are doing the work aren't involved in the design of that work, then they're not always aware of the hazards."
Professor Quinlan said that complacency was an issue in mines where incidents hadn't occurred.
"When the system corrodes over time, because everything's worked, people get a bit too casual about it and then you can find that your systems are not working," he said.
Queensland Police told the ABC it would complete its investigation into the deaths of Mr Langridge and Mr Davis this week and the RSHQ is investigating the circumstances that led to the two mens' deaths.
