New Zealand has seen its share of mine disasters, with 181 people killed since 1896. Today, 36 people are missing after an explosion at the Pike River coal mine.
The mine, about 46km northeast of Greymouth is on the opposite side of the Paparoa Ranges from the now-closed Strongman State Mine where 19 miners died in an explosion in January 1967.
In that disaster, 240 men were working in the mine at the time, but a wet patch 140m down the tunnel put out the fireball from the explosion.
Pike River takes its high-quality coking coal from the estimated 58 million tonnes in the Brunner coal measures - with another 29 million tonnes thought to be in the Paparoa seam 150m below .
The coal from the Brunner seam has a very low ash content, at 1 per cent compared to 8 per cent in premium Australian coking coals. It also has low phosphorous levels but moderate sulphur levels.
It was that coal that was being collected by the men when they were killed in the nation's worst industrial disaster - the Brunner mine deaths in which 65 men died in March 1896, killed by gas.
New Zealand's mine disasters include:
Kaitangata, February 1879: Candles cause explosion in an area known for methane (firedamp) killed 34 men and boys.
Brunner, March 1896: Incorrect blasting set off a gas explosion - probably methane - killing 65 men.
Huntly, Ralph's mine, September 1914: A miner's naked light ignited firedamp, killing 43 men.
Dobson mine, December 1926: An explosion killed nine men.
Huntly, Glen Afton mine, September 1939: Carbon monoxide asphyxiated 11 men.
Strongman mine, 11km northeast of Greymouth, January 1967: explosion killed 19 miners.
Black Reef Mine, near Greymouth, March 2006 - Robert McGowan, 39, drowned when he hit flooded mine workings.
According to a West Coast historian Brian Wood, who has written several books on mining, most of the nation's serious accidents have occurred in coal mines, which are different to hard-rock mines.
"You've had your quartz-mining areas in Thames, Waihi and Reefton, but there's not been a major entrapment of miners underground in any of those mines," he said.
In 1970, four workers died and others were trapped for two days when the Kaimai railway tunnel collapsed.
The shaft of the Waiuta goldmine, near Reefton, collapsed in 1951. There was nobody underground.