B.C. mine pollution cited
Vale N.L. employee says its release of waste was controlled and non-toxic
Vale told provincial court it was trying to avoid disaster like Mount Polley.
Vale Newfoundland and Labrador did not want Voisey’s Bay to become another Mount Polley.
That was the message unexpectedly conveyed in provincial court in St. John’s Thursday, as proceedings continued in the trial of a case involving two allegations of Fisheries Act violations by Vale Newfoundland and Labrador, dating back to October 2011.
The company is accused of sending wastewater lethal to fish into Anaktalak Bay, on the Labrador coast.
An environmental co-ordinator at the mine and Vale Newfoundland and Labrador employee, Erin Cullen, continued on the stand Thursday, walking through the month before there was a series of failures in “acute lethality” tests, regulatory tests, on what was being piped under permit.
The company failed tests on Oct. 4, Oct. 10 and Oct. 24, according to Environment Canada logs, but kept releasing its effluent through the month.
Cullen maintains what was released off site was not harmful. Under questioning, she spoke about the mine’s tailings impoundment area, known as Headwater Pond.
She said in September 2011 a pipeline used to run wastewater from Headwater Pond to a treatment plant, before sampling and release into the environment, was taken offline for cleaning.
Wastewater was not being treated and released while the pipeline was off, she said.
Instead, it was building up in the impoundment area.
The cleaning of the pipeline would allow the company a greater flow as needed, she said. It would allow the mining company to properly manage water levels in the impoundment area and keep pressure off the tops of its earthen dams.
Flooding risk
Without the cleaning, it was suggested, there was an increased risk of buildup and a dam failure, ultimately flooding the surrounding area with untreated waste — as in the case of the mine in Mount Polley, B.C. in August 2014.
A failure of a tailings dam at that Imperial Metals coppergold mine released an estimated 10 million cubic metres of water, 13.8 million cubic metres of tailings slurry and 0.6 million cubic metres of construction waste, into the surrounding environment, according to reports.
“They had a similar tailings impoundment area,” Cullen told the court.
She suggested without cleaning the pipeline at Voisey’s Bay and increasing the flow of wastewater out of the impoundment, “we are at a serious risk of (eventually) stressing a dam or overtopping a dam.”
However, when the pipeline cleaning was underway, no wastewater could be released. It made releasing effluent in October all the more important to the company.
“We were absolutely anxious to get the treatment started again and get our discharge flowing again,” she said.
Using the measure of Olympic-sized swimming pools, Vale Newfoundland and Labrador released roughly 197 pools of treated wastewater under standard procedure in October 2011.
Estimates of what was released in the spill at Mount Polley have increased over time, but run to approximately 2,000 swimming pools, with solid wastes mixed in.
Investigations into the damage from the Mount Polley spill continue. A report released in January from geotechnicians Norbert Morganstern, Steve Vick and Dirk van Zyl attributed the dam failure there to a design flaw, with the dam being built on a weak layer of glacial deposits.