Explained: What’s happening at scene of mining site tragedy

As a massive search operation tragically found two miners dead 125m underground at Queensland’s Dugald River mine, experts have weighed in about what was likely happening at the site.

As two miners were tragically found dead in a search at the Dugald River mine, 70km northwest of Cloncurry, experts have weighed in about what was likely happening at the site.

Dylan Langridge and Trevor Davis were in a vehicle that fell into a stope void on Wednesday. The vehicle was found on Thursday morning some 125m underground, and the miners’ bodies later in the day.

What are the conditions like?

University of Queensland mining expert Professor David Cliff said air quality in a mine like Dugald River would be good.

“The air is pretty good and tends to be fresh. where they are now would still be reasonable quality if they have access to fresh air,” he said.

“There is no gas apart from the diesel vehicle exhaust fumes and residual blasting fume.”

Professor Cliff said although the situation was different the conditions would not be dissimilar to those faced in Tasmania’s Beaconsfield goldmine in 2006, in which a collapse killed one miner and trapped two others underground for two weeks.

There is no mobile phone coverage in the mine, however the vehicles would be fitted with two-way radios and the individuals may also have radios.

In some mines there are wifi systems that connect to VOIP phones.

Machinery working the Dugald River mine. Picture: MMG

How does the mine work?

Dugald River is an underground ore mine that is mined using a technique called sublevel stoping.

“Typically the ore body, the stuff that you’re after, exists as a vertical column of material,” he said.

“You make a roadway spiralling down, usually around the outside of (the ore body) or down one side of it, and from that roadway, you then drill into it, then use explosives to break up the rock to extract the ore at various horizontal levels as you go down.”

Professor Cliff said it was not clear how the miners had fallen into the stope, but a mining industry insider told The Courier-Mail he suspected the workers were carrying out ground stabilising works.

“There’s no normal way for a cavity to form underneath, unless there’s a pre-existing roadway or other tunnel,” Professor Cliff said.

Dylan Langridge is one of two miners killed in an incident at the Dugald River mine in Cloncurry. Picture: Facebook

Trevor Davis is one of two miners killed in an incident at the Dugald River mine in Cloncurry. Picture: Facebook

Recovery efforts

Highly skilled mine rescue teams are onsite and Professor Cliff said they would be tasked with a very complex operation.

“First of all, they have got to get down 25m into the cavity to find the people and they need to do that without exposing themselves to the risk of further rockfalls,” he said.

“Because presumably, the size of the cavity suddenly appeared and we don’t know how stable they are.”

Rescue teams will need to bring in heavy equipment to remove the rocks that are on top of the ute – some of which may weigh multiple tonnes.

“All the details have not been released but to extricate those people from that area will be pretty difficult. They have got some highly skilled rescue team members who know this stuff and they know about abseiling and getting down into cavities but as you appreciate getting the gear down into the mines, and then into that area to be able to use it safely without risking further rock falls and things occurring and to have good access is a challenge.”

Originally published as Explained: What’s happening at scene of mining site tragedy