A Mosaic potash mine site in Belle Plaine, Saskatchewan is seen in this September 29, 2010 file photo. (REUTERS/David Stobbe/Files)

A fire broke out at a Saskatchewan potash mine Monday, trapping 318 workers underground for more than 12 hours.

The fire started at around 10:30 a.m., and the last of the miners were rescued by midnight, said Brad DeLorey, spokesman for Mosaic's K2 potash mine near Esterhazy in eastern Saskatchewan.

Nobody was injured and all the miners are accounted for.

DeLorey said a piece of mobile equipment caught fire and the mine followed emergency procedures by sending everyone to underground refuge stations — "sealed-off areas that provide them with food, water and clean air" — while officials determined whether the air quality and ventilation were safe.

"I just want to stress that emergency responders are prepared and they were utilizing the skills and training they have and everything worked out because of that expertise," DeLorey said.