A miner died from asphyxiation when he was buried in a pit after the roof collapsed, an inquest heard today.
Gerry Gibson, 49, from Sherburn-in-Elmet, North Yorkshire, died last Tuesday when he and a colleague were trapped by a rock fall in Kellingley Colliery.
Initial investigations have shown there was a failure of the roof support system at the mine, the inquest at Selby Magistrates' Court heard.
Giving evidence at the inquest opening, John Whyatt, a mine inspector, said it would take around six months for inquiries into the incident to be completed.
Mr Whyatt said he began his investigations at the mine on Tuesday after being told that two men had been "buried".
He said: "It is clear from my initial overview there had been a failure of the support system."
The inspector said equipment from the mine had now been sent away for analysis.
"I would expect it to be maybe six months before we are in a position to give a final report," he said.
"One of our focuses is not just to understand what's happened in this case, but the really important part is to make sure measures are put in place to stop it ever happening again."
Mr Gibson's wife, Brenda, attended the inquest with her son, Sean, and other members of her husband's family.
When asked by North Yorkshire Coroner Rob Turnbull if she had any questions, Mrs Gibson said: "The main thing is just to make sure it doesn't happen again."
Opening and adjourning the inquest until a later date, Mr Turnbull said: "The conclusion from the examination of Mr Gibson's body was the cause of death was given as mechanical asphyxia due to the collapse of the mine roof."
A major rescue operation was launched on Tuesday evening to try to rescue Mr Gibson and colleague Phil Sheldon after the roof collapsed 2,625ft (800m) underground.
Mr Sheldon was rescued with minor injuries after being trapped by his leg in the incident but Mr Gibson was pronounced dead at the scene.
On Friday, Mr Gibson's family said they were "devastated" by his death and paid tribute to all those involved in the rescue effort.
Mr Gibson was originally from Shotts, North Lanarkshire, and the Scottish National Union of Mineworkers said he would be "sorely missed".
Mr Gibson's death is the third at Kellingley in three years.
Ian Cameron, 46, died when equipment fell on him at the pit in October 2009 and miner Don Cook died in a rock fall in September 2008.
UK Coal, which runs Kellingley Colliery, appeared at Pontefract Magistrates' Court on Friday in relation to the death of Mr Cameron.
The Doncaster-based company is accused of health and safety breaches, including failing to ensure that powered roof supports at the coal face were maintained in an efficient state; exposing people to health and safety risks; and not ensuring the health and safety of its employees, including Mr Cameron.
UK Coal appeared alongside mining equipment firm Joy Mining Machinery Ltd, which is charged with failing to provide all the necessary information about health and safety risks in relation to using the powered roof supports.
The case was adjourned until October 24.
UK Coal is due to be sentenced later this month in a separate prosecution for breaching health and safety regulations in cases relating to the deaths of four miners at pits in the Midlands.
The firm has admitted safety breaches in relation to the deaths of Trevor Steeples, 46, at the Daw Mill colliery, near Coventry, in June 2006; Paul Hunt, who died in August 2006 following another accident at Daw Mill; Anthony Garrigan, who died in January 2007, again at Daw Mill; and Paul Milner, who was fatally injured at Welbeck Colliery, near Mansfield, Notts, in November 2007.