Underground mining contractor Barminco confirmed today that the employee was killed in an accident about 7.50am local time.

Tasmanian police confirmed the worker as a 53-year-old man and said Worksafe Tasmania mine inspectors were attending the scene.

The Australian Workers Union attributed the death to a mudslide at the mine and described the deceased as a Queenstown local.

Investigations into the incident are ongoing, with police forensics officers and the coroner attending.

Next of kin have been notified.

Copper Mines of Tasmania general manager Scot Clyde said that it was with extreme regret that he confirmed the death of an underground miner.

"Our deepest sympathies are with the family of the worker, his immediate workmates and also our other site employees who will be saddened by this tragic accident," Clyde said.

Barminco also released a statement expressing sympathy to the family, friends and colleagues of the employee.

The AWU called the incident a "huge tragedy" for a community still reeling from the death of two men aged 25 and 45 at Mount Lyell on December 9.

"On behalf of AWU members across Tasmania and the rest of the country, I want to express our deepest condolences to the family, friends and co-workers of this local man as they come to terms with this deeply distressing news," AWU acting national secretary Scott McDine said.

"His death is a huge tragedy and will be a major blow to a town already experiencing a deep sadness."

AWU Tasmanian branch secretary Ian Wakefield said the union would be travelling to the mine today to offer extra support, with the latest death hitting many workers particularly hard because it followed so soon after the previous losses.

"Queenstown is a close-knit mining community that was already struggling to come to terms with a tragic double-fatality at the Mount Lyell mine last month, so to lose another colleague so soon after has understandably been absolutely devastating," Wakefield said.

"The community has lost a well-regarded member, our mining community has lost a respected colleague, and a local family has been devastated by having a loved one torn away from them without warning.

"Words cannot express just how difficult it will be for them to deal with this tragic death."

Barminco said the worker, a loader operator, was unresponsive when found by CMT's mines rescue team following a mud rush in the lower levels of the mine. Paramedics, an ambulance and police also attended.

Operations at the mine have been suspended while investigations take place.

Counsellors are being mobilised to site and their services will be available to all those involved.

The pair lost last month died after falling 35m from a maintenance platform in the mine's main shaft.

The historic mine, which began operations in 1896, was reopened by Copper Mines of Tasmania in 1995.

Operations involve a sub-level caving mining method, with work being carried out at 1000m below the original surface of 600m below 0m.

Production is about 2.7 million tonnes per annum of ore at 1.25% copper grade.

Copper Mines of Tasmania is part of the Vedanta group of companies.