The 29 missing miners were expected to have died within minutes of the first explosion, according to expert opinion.

While there are several inquiries into the disaster, only limited-scope evidence is being presented to the coronial inquest to protect the findings of the Royal Commission of Inquiry, which must be submitted to the NZ governor-general by March 31, 2012.

One of the two survivors of the tragedy, Daniel Rockhouse, provided evidence of how the mine began to fill up with smoke and how he could smell carbon monoxide after the first explosion.

Rockhouse lost consciousness after pulling off his self-contained self-rescuer, but was able to recover and used a compressed air pipe in the mine to get fresh air.

He later made it to the phone underground to report the accident, and rescued fellow survivor Russell Smith.

University of Otago’s Dr Robin Griffiths said in his testimony that the other miners would have died within minutes of the explosion, given the fatal level of carbon monoxide.

Citing other experts, NZ Police superintendent Gary Knowles said the level of oxygen was about 1% and the first two explosions would have created temperatures of up to 2000 degrees Celsius.

Other evidence was provided by University of Queensland’s Minerals Industry Safety and Health Centre associate professor and operations manager David Cliff and a statement by Pike River Coal’s general manager Doug White was read to the court.

Management could not confirm the number of miners underground at the time of the first explosion.

To aid identification, Knowles revealed that the locker room had been searched, while the serial numbers of each issued cap lamp were checked.

Live coverage of the inquiry is available through TVNZ’s website.

The first explosion struck on Friday, November 19, and the second explosion on November 24 ended hopes for finding any more survivors.

Damage from subsequent explosions and a fire underground further complicated the recovery effort.