More than 300 miners who were trapped underground at a Saskatchewan mining site after a fire broke out are safe and above ground this morning.

A fire at Mosaic’s K2 potash mine near Esterhazy, Sask. started Monday morning, sending 318 miners to underground refuge stations where they waited for hours as emergency crews put out the blaze and the heavy smoke cleared.

The fire broke out at 10:35 a.m. and it took more than six hours for evacuation efforts to begin.

A spokesperson for Mosaic told on Tuesday that the rescue efforts wrapped up around midnight and no injuries have been reported.

“We are currently working to investigate the potential cause,” said Brad DeLorey, adding that a piece of mobile mining equipment is believed to be the source of the blaze.

DeLorey said operations at the mining site are expected to resume Tuesday afternoon.

The last underground fire that forced an evacuation at the Esterhazy mine occurred in 2006.