The second explosion "vindicated" the decision not to send rescue teams in to find 29 trapped miners including two Britons in New Zealand, a mining expert has said.
Police said the workers would not have survived the "horrific" second explosion at the Pike River mine in Atarau on the country's South Island and rescue teams were "now in recovery mode".
Pete Rodger, 40, from Perthshire, and Malcolm Campbell, 25, from St Andrews, Fife, are among the men missing following Friday's initial blast.
Rescue teams were unable to go into the mine after the first explosion because of high levels of toxic gases.
Patrick Foster, a senior lecturer in mining engineering at the Camborne School of Mines, part of the University of Exeter, said if rescuers had been sent in and the explosion had taken place it would have been "far worse".
Earlier, the Queen said she was "deeply saddened" after police confirmed the mission was "now in recovery mode". New Zealand's prime minister John Key said the country was "a nation in mourning".
A drilling team broke through on Tuesday to the section of mine where the men were working but were greeted by a blast of potentially deadly gases.
Pike River mine chief executive Peter Whittall said the rescue teams were not doing anything that could have triggered the second blast.
Pike River has operated since 2008, mining a seam with 58.5 million tons of coal, the largest-known deposit of hard coking coal in New Zealand, according to its website.
The mine is not far from the site of one of New Zealand's worst mining disasters: an underground explosion in the state-owned Strongman Mine on January 19 1967, which killed 19 workers.
The country's worst disaster was in 1896, when 65 died in a gas explosion, which also occurred in the same Pike River coal seam.
