Hopes of retrieving the bodies of 29 workers at the Pike River coal mine have been dealt another blow with the announcement that an explosion has started a coal fire in the mine.
The fourth explosion since 19 November occurred at about 2pm on Sunday.
Pike River bosses say coal smoke and flames, rather than gas, are now coming out of the shaft, and it's likely that coal brought down by the explosions is on fire.
Chief executive Peter Whittall says it may be necessary to seal the mine - at least temporarily - to put out the fire, before using a jet engine, known as a GAG machine, to expel gases.
He says sealing the mine temporarily would help to starve it of oxygen, but it would take more time because the mine would have to be made air-tight.
Mr Whittall says he has told the miners' families that the last two explosions will make the recovery of the bodies an even longer process.
At times there have been up to 180 people on site working towards effecting a recovery.
