Mount Isa Police Inspector Trevor Kidd said the search is now in its second phase with police no longer believing Mr Kelly is alive.

"The opportunity to recover the person alive no longer exists," Insp Kidd said.

"There will be a different allocation of resources.”

Mount Isa Mines has acknowledged the statement by the police confirming the search to locate Mr Kelly had ceased.

“Mount Isa Mines acknowledges the statement by the Queensland Police Service (QPS) confirming the search to locate our missing employee Brett Kelly at our Mount Isa Copper Operations have ceased and we are working with the QPS on the next stage,” the statement read.

North Queensland Copper Operations Chief Operating Officer Mike Westerman said during the search Mount Isa Mines had more than 200 of its copper employees assisting the Mines Rescue Teams and the Queensland Police Service with the search.

“I am deeply saddened and disappointed that we have been unable to locate Brett,” Mr Westerman said.

“After it was identified on Wednesday (18 June) that Brett was missing, all activities in our underground copper operations ceased, we immediately mobilised a significant number of our underground workforce in an extensive effort to find him.

“We are now continuing to work with the Queensland Police Service, the Department of Natural Resources and Mines and other relevant authorities as part of the ongoing investigation into this matter.

“We are also keeping Brett’s family fully informed and providing them with all the support we can.”

Mr Kelly was last seen on Wednesday at 11.30am on Wednesday.

THE identity of the man missing from the Mount Isa Mines site has been revealed to be Soldiers Hill man Brett Michael Kelly.

A bomb squad robotic search unit called in from Townsville has not been able to help find Mr Kelly, 34.

Mount Isa Police Inspector Trevor Kidd said police and staff from mine operator Glencore were focusing their searches in the underground tunnels where the Mount Isa man was last seen on Wednesday at 11.30am.

Police were advised about four hours later, after an initial search failed to find the 34-year-old.

Glencore is leading the search with the assistance of local police.

Inspector Kidd said authorities had requested a robot from the police Explosive Ordnance Response Team (EORT) in Townsville to help search the difficult terrain.

Inspector Kidd said police had used the technology at Mount Isa Mines before.

The $750,000 robot is capable of taking photographs and conducting searches of hard to reach areas underground.

It features multiple cameras and lighting, on-board tool set including a drill, grinder and cutter, and pressure-driven manipulator claws.

“It’s obviously a complex industrial site so we’re utilising the expertise of Mount Isa Mines search and rescue teams to search those areas,” Inspector Kidd said.

“If you picture a small track vehicle, you've got to have reasonable terrain to try to move it around. It’s an underground mine, a kilometre or so beneath the ground, with a whole series of tunnels and vertical shafts.” 

“It’s a dangerous working environment; it’s bare rock, high temperatures and low visibility.

“Police are providing assistance with queries from the community and providing search and rescue people.”

It is unclear why Mr Kelly has gone missing as there is no sign of cave-ins or collapses in any of the tunnels.

Inspector Kidd described the underground mine as a “hostile environment”, with the search area including several vertical tunnels as deep as 1.5 kilometres.

The tunnels and shafts were not concreted or brightly lit which added to the difficulty.

Search parties were also examining maps of the mine in detail and was repeatedly checking the same ground being searched, Inspector Kidd said.

Police were also collaborating with the Queensland Mining and Safety Mining Inspectorate.

A Department of Natural Resources and Mines spokesman said Glencore were leading the search but that the department was monitoring the situation.

In a statement MIM said "emergency procedures were activated as the search continues to locate the missing person in conjunction with the police". 

Mr Kelly’s family were further briefed on the search on Friday.