The epicentre of the earthquake was pinpointed five kilometres below the surface, very near the K2 potash mine and the village of Gerald. In this image from the US Geological Survey, the epicentre is shown as the star at the top right. Highway 22 is across the bottom.

4.1 magnitude earthquake at Esterhazy leads to power outage

August 19, 2019 7:34 am
Kevin Weedmark

A 4.1 magnitude earthquake 17 km east of Esterhazy Thursday evening caused a power outage across the area for two and a half hours that halted production and Mosaic’s mines.

“Several transformers at the Tantallon switching station tripped off during the earthquake,” said Joel Cherry of SaskPower. “A piece of transformer equipment called a gas relay that responds to gas leaks or sudden pressure changes was set off by vibrations caused by the earthquake.”

He said the length of the power outage was because SaskPower crews had to go to the Tantallon site, inspect, and manually reset the equipment after the earthquake.

“For safety reasons the transformer can’t be re-energized until it is visually inspected and manually reset. No damage was done to our equipment and everything is back up and running now.”

The U.S. Geological Survey says the quake, which rocked the area at around 8:30 p.m. CST Thursday was 4.1 in magnitude, and was centred about five kilometres below the surface, very near Mosaic’s K2 potash mine and the community of Gerald.

Sarah Fedorchuk, Vice President, Public Affairs and Government Relations at The Mosaic Company, said production halted at Mosaic Esterhazy during the power outage.

Fedorchuk said a CBC report that miners were sent to refuge stations was false.

“There was some media reports that were incorrect that we put employees in refuge stations, but we didn’t,” Fedorchuk told the World-Spectator Friday morning.

“There was no property damage or injury, but due to the power outage we did gather our underground employees just to account for everybody.

“We have backup generators and we can choose to operate the hoist. Often we don’t because it is a limited power source and we choose to do other things with it. If push comes to shove we can often operate different parts of the operation from backup power for a short time if we have to.

“In this case we halted production for a couple of hours and then carried on.”

She said in a seismic event, the protocol is to muster the employees and make sure everyone is accounted for.
Fedorchuk said geologists routinely monitor seismic data in the mining area.

“It is not unusual to have some sort of mild seismic activity when you have mining in an area,” she said. “We do have geologists looking at different seismic data on a continual basis just as part of our routine operations.”

About half of the earthquakes reported in Saskatchewan are in the Esterhazy area. Geologists attribute the seismic activity in the area to interaction of groundwater with Potassium Chloride (Potash) and Calcium Chloride (Salt) at the edges of the Prairie Evaporite Formation. Both are soluble minerals, and will dissolve on contact with water, leading to ground settling causing earthquakes.

There have been 17 earthquakes of similar magnitude in the Esterhazy area since 1981. There was a 3.8 magnitude earthquake at Esterhazy in 2016.

Quake felt in Qu’Appelle Valley

Dave McGowan of Esterhazy said he felt the earthquake in the valley near Tantallon Thursday night.

“I live in Esterhazy but for the week I’ve been down at my parent’s farm in the valley 5 km west of Tantallon,” McGowan said.

“We were watching TV and all of a sudden the ground shook and the couch shook and then the power was gone. It was like sitting on a porch swing, just kind of gradual

“It was like ‘well that’s an earthquake.’ ”

He said he has experienced earthquakes before in the area.

“There was one other time, we were up in town, it was about the same, but I don’t think we lost power or anything,” he said.

McGowan is originally from the west coast and has lived in Esterhazy for about eight years.

Felt earthquakes before

Sue Arnason said the shaking from the earthquake was enough to rattle knickknacks at her home near the Qu’Appelle Valley.

“I live on the farm and I’m about a mile and a half from Tantallon east and from the mine, about five miles from K2 south of K2,” she said. “We are very close, I can see the mines very easily from my place, I’m right on the edge of the Qu’Appelle Valley at the top.”

She said the earthquake startled her.

“I was actually watching a movie and playing on my computer and power went out and all of a sudden I could feel the whole house shaking and the knickknacks on the top of my computer desk rattled. I could really feel it.

“At first I thought, because we had so much rain before that, that maybe there had been a lightning strike right beside my house, so I went out and looked and I couldn’t see anything.

“The transformer on my power post was still intact, and then I phoned my son, he lives in the same yard as me in a trailer, and I said ‘did you feel that,’ and he said ‘yeah me and the kids were laying down and we really felt it. It felt like when a washer was on a spin cycle and you stand beside it, it shook like that.’

“I really felt it, my whole body too, it was strange, very strange. It lasted quite a few seconds, maybe five seconds.”

She said she has felt earthquakes in the area in the past.

“In the early 1990s, before 1994, we had a small one and we had a deer head hanging on the wall and it got knocked off the wall.

“And then there was a small one one other time that we sort of felt, but we didn’t really even realize that was what it was until someone said something.”