All 72 workers trapped in a Saskatchewan potash mine have been rescued after spending more than 24 hours trapped by a fire deep below the earth's surface.

The final five workers, who were farthest from the escape route, reached the surface at around 8 a.m. CT.

"It really is a good news story," Marshall Hamilton, spokesman for mine owner Mosaic Company, told CTV Newsnet Monday. 

"It's because of the training of our people that we're happy to report that everybody is safe."

Thirty-two of the miners were brought to the surface by rescue workers at about 3:30 a.m. CT, and another 35 came out a couple of hours later, followed by the remaining five.

Mosaic CEO Fritz Corrigan said there will be a "thorough investigation" to identify the cause of the blaze.

"Safety is a core part of our culture at Mosaic. Our actions today have demonstrated this," Corrigan told reporters. 

Reporting from Esterhazy, Sask., CTV's Sarah Galashan said the rescued workers "just felt extreme relief."

"It's a relief to everybody here who's been up through the night," she said.

"At one point 32 of the workers in one of the safe rooms lost communication with the surface and no one knew how they were doing."

Trapped

The miners, most of whom are employed by contractor Dynatech, were trapped when fire broke out in polyethylene piping nearly a kilometre underground at the K2 Mosaic Mine near Esterhazy, Sask., at about 3 a.m. CT on Sunday.

When toxic smoke began to fill the tunnels, the miners retreated to so-called safe rooms -- spacious chambers that can be sealed off and are equipped with supplies of oxygen, food and water.

Within two hours, rescue teams were mobilized, each going into the mine for a few hours at a time.

"The safe thing to do and the procedure we've established is in the event you see smoke you immediately retreat to one of the refuge stations and once you're there, seal yourself off," Hamilton added.

"In those refuge stations, the workers can seal themselves in with enough oxygen and food and water to be comfortable for the next 36 hours at least."

Most of the miners had been underground since Saturday night, having started work at 7 p.m. CT.

The delay in bringing the miners to safety was caused by the sheer distance the rescuers had to travel, Hamilton said.

"It's just a huge mine. Our mine footprint is approximately 20 kilometres by 30 kilometres, and it takes people a long time to get from the shaft out to those workers."

Rob Dyck, one of the members of the rescue team, said rescuers had to ensure that smoke and toxic fumes were cleared before the miners could leave their refuge stations.

"It was hot, dusty, but our training came through," Dyck said. "We've been in smoke before, but probably nothing this complicated."

Safety

Miner Greg Harris said he was never really concerned about his safety as he played a makeshift game of checkers with colleagues while they waited to be rescued.

He and his friends drew the checkerboard on the back of a map and used washers as playing pieces.

"Everything is good," an exhausted Harris told The Canadian Press from his home Monday afternoon. "Communication was excellent. We had no problems whatsoever."

Meanwhile, Hamilton praised the rescue efforts, saying everything had gone according to plan. 

"You would be hard pressed to find a mining operation anywhere in the world that has a better safety record than Mosaic here in Esterhazy," Hamilton told reporters. 

"In fact, it's safer to work in a potash mine in Saskatchewan than it is to work in an office job for the government of Saskatchewan," he said, referring to the workers' compensation board.

The mine, which was Saskatchewan's first potash operation when it opened in 1962, is located about 125 miles northeast of Regina, not far from the Manitoba border. 

Potash is a pinkish-grey mineral used in the production of agricultural fertilizer.

Mining tragedies

Earlier this month, 14 miners died in two separate tragedies at mines in West Virginia. Two men died in a belt-line fire Jan. 21 at a mine in Melville, nearly three weeks after 12 men died after an explosion near Tallmansville.

China has the world's deadliest mining industry and reports disasters regularly. The Beijing government has launched a series of safety campaigns in recent years in an attempt to rein in accidents that kill more than 5,000 Chinese coal miners annually, but death tolls are largely unchanged.

China said recently it was closing 5,290 coal mines as part of a safety crackdown.