Two trapped miners remained “125 metres below the surface” on Wednesday night as an urgent rescue mission was being planned in north Queensland, the mining parent company said.

Drones fitted with video and data-collection technology were being used to assess the underground zinc mine, Perenti said in its updated statement.

“The rescue will commence post analysis of the data and in accordance with a rescue management plan,” it said.

“We believe the two missing Barminco employees remain 125 metres below the surface and we are using drone technology to understand the specific conditions of the area.”

The ABC reports the men were believed to have been operating a ute that fell down a 25-metre void in a previously filled stope — a cavernous, void-like structure from which ore is extracted.

The ABC reports the accident happened at 8.45am at MMG Ltd’s Dugald River underground mine site, outside Cloncurry, while there were other media reports that the accident happened at 1pm.

Paramedics said they had responded to a “ground collapse” after 1pm on Wednesday.

A 30-tonne drilling rig reportedly fell into the hole after the ute. The rig operator was able to escape and is in a stable condition.

An underground mining operation at Dugald River. Photo: MMG

Perenti chief executive Mark Norwell said a safe and quick rescue was the priority.

“Everyone at Perenti is feeling the impact of this incident and we continue to be hopeful that a positive outcome can be achieved,” Mr Norwell said.

The mine’s operator MMG suspended work as the search continued for two Barminco contractors “unaccounted for” after the incident.

“Two Barminco employees working at MMG’s Dugald River mine in Queensland were this morning involved in an incident and currently remain unaccounted for,” the company said in a statement on Wednesday afternoon.

“The site’s emergency response has been activated and is working closely with Barminco and authorities to assist in search and rescue efforts. Operations at Dugald River have been halted while the search is under way.

“MMG has extended all available resources and support to Barminco and the Dugald River Mine.”

In a release to the ASX, Barminco owner Perenti said the situation was evolving and the team was supporting family members and colleagues.

Local state MP Robbie Katter said the event was “obviously the worst nightmare” for a mining community and there was a lot of anxiety.

“We know emergency services are on the ground and we are praying for a good outcome,” he said in a statement.

“My major concern is the wellbeing of these two employees and the task at hand to get them back safely to their families.”

Inspectors from Resources Safety Queensland are also onsite assisting emergency responders.

MMG states Dugald River is one of the world’s top 10 zinc operations.

Ore is mined underground using diamond drilling techniques and extracted to the surface.