UPDATE: 10:30 a.m.
Peter Martell, superintendent of environment and community affairs with Teck Resources Limited, clarified that the 225,000 gallons of water did not breach the actual tailings dam, but came from a damaged pipeline that fed into an onsite pump house.
The water did cut a large trench down the face of the sand dam, but the structural integrity of the dam was never compromised.
ORIGINAL: 5 a.m.
The largest sand tailings dam in North America spilled 225,000 gallons of contaminated water Saturday and it wasn't noticed for three hours.
The spill occurred at Highland Valley Copper mine, located 50 kilometres southwest of Kamloops, cutting a 4.5-metre deep and six-metre wide trench down the face of the 140-metre high dam, according to Kyle Wolff, president of the United Steel Workers Local 7619 union, which represents 1,000 workers at the mine.
Wolff says although the release of water didn't impact the structural integrity of the dam and the contaminated water didn't make it's way past the mine's containment system at the base of the dam, the leaking dam wasn't noticed for three hours.
He says a spill of this size is "absolutely not" a regular occurrence.
While Peter Martell, superintendent of environment and community affairs with Teck Resources Limited, the operator of the mine, could not confirm the cause of the spill, Wolff says it was caused by water leaking into a pipe over the winter and freezing, separating it from another pipe.
He says they've learned about the damage from a union member, but received no information from Teck. Wolff was under the impression the spill occurred Sunday, while Martell said the spill was on Saturday.
In February 2016, the Cyclone House, a station used while additions are being added onto the dam, was temporarily closed down. Workers that were stationed there full time, keeping an eye on the dam's face, were sent elsewhere.
Wolff says when this decision was made, the union brought up their concerns to the company, but they were not heard.
“If something like this happens (a spill), we can't catch it early and it can escalate to something very serious,” he said. “You're talking about running water down a sand damn, the potential over time is, there's potential to cut in and create more damage.”
Wolff says this is the first time he has seen the Cyclone House unmanned in the 11 years he has been involved with the mine.
Teck's Martell says those operators are not required at the Cyclone House to inspect the dam when it's not in operation.
“That's carried out by our dam inspectors, and they're there everyday,” Martell said. “They're responsible for inspecting all the impounds (dams) on site.”
A 2014 Highland Valley Tailings Storage Facility Operation, Maintenance & Surveillance Manual calls for the Cyclone House Operator to visually monitor the dam every two hours to ensure "there are no leaking pipeline joints or other unusual problems."
“Not having those people there (at the Cyclone House) definitely contributed to that. If they were there they would have realized there was something going wrong,” Wolff said. “It put a lot of that pressure onto other individuals who are inspecting an entire site, not just one particular area.
“Three hours is three hours, if it had been eight or 10, it would be a very different situation.”
Wolff also says the union wasn't informed of the spill until Monday or Tuesday, after it was cleaned up, and the union was first to inform the Occupational Health, Safety and Environment Committee of the spill, not the company.
“There seems to be a bit of mischievousness going on right now,” Wolff said.
Martell says Teck informed the union of the spill “as soon as was practical” and he said he believes the safety committee was informed as well.
The Ministry of Energy and Mines was informed of the spill by Teck, but a ministry representative told Castanet they could not provide any information about it because the provincial election is ongoing.
The union says they've had increasing safety concerns at the mine over the last few years.
“We've seen a drastic increase of severe safety incidents,” said Wolff.
“What it comes down to, and they'll refute this to the end of the day, we're putting production over safety.”
Martell says at Highland Valley, “safety is always a priority over production.”