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Power outage traps miners underground after earthquake

Quake measured 3.8 on Richter scale


(Canadian OH&S News) — An earthquake in southeastern Saskatchewan led to a power outage that trapped around 40 miners underground at a potash mine near Rocanville, on the morning of Sept. 5.

The quake occurred at about 4:40 a.m., had a depth of around one kilometre and measured 3.8 on the Richter scale, according to information from Earthquakes Canada. It was centred near Yorkton and was also felt in Esterhazy, Tantallon and Gerald.

The effects of the quake knocked out the power at a regional substation near the PotashCorp Rocanville mine, shutting down power to a large part of the area, according to Randy Burton, PotashCorp’s director of public relations and communications.

“Under normal circumstances, our emergency generator would kick in,” said Burton, referring to the Rocanville mine’s backup power. “We had a switch problem. An automatic transfer switch didn’t work as expected, and it shut the generator down.”

As a result, a hoist at one of the mine’s shafts could not run, meaning that two mining crews had no way to return to the surface. The miners stayed in an underground refuge station until around 11 a.m., when the power returned.

“Potash mines are big shafts, and they cut out refuge stations where there’s air supply, water and facilities,” explained Burton. “In the event of a serious emergency, miners go to refuge stations. So they did that in this case and essentially just had to wait for a few hours until power was restored and the hoist was operational again.”

All of the workers emerged safely from the mine that morning. “There was never any question about safety,” added Burton. “The tremor did not cause any damage to the mine.”

This was not the first time such an event had occurred at this mine. In Sept. 2012, an earthquake sparked a fire and trapped workers there underground for about 24 hours. There have been 12 earthquakes in the region measuring at three or higher on the Richter scale over the past 35 years, according to information from Natural Resources Canada.

But Burton said that incidents such as the Sept. 5 power outage are relatively rare at PotashCorp’s mines.

“I do believe there have been previous tremors. I’m aware of at least a couple I’ve seen reported in the news over the past three or four years,” he said.

“Safety’s number one at all these sites,” Burton added. “The procedures, protocols are built in that if anything’s not working the way it’s supposed to, everybody knows where to go and what to do.”

PotashCorp is the world’s biggest fertilizer company by capacity and produces potash, nitrogen and phosphate, according to the company’s website. Its Rocanville mine provides standard and granular potash for use in fertilizer and agricultural products across North America.

Rocanville is located around 230 kilometres east of Regina.