Another West Coast coal mine was evacuated a week before the Pike River Coal explosion because of the risk of spontaneous combustion.
Solid Energy has confirmed that workers at its Spring Creek mine, 15km north of Greymouth, were evacuated when the mine's monitoring system detected early signs of spontaneous combustion in the coal.
It says up to 10 of the mine's 180 workers were in the mine at the time - a low number because it was a Friday night.
It says spontaneous combustion is a well-understood hazard in underground mines worldwide and Spring Creek's systems worked well.
The mine reopened four days later.
