The NWT’s Diavik diamond mine says workers are waiting for “extreme weather” to end before a broken pipeline responsible for a significant leak can be fixed.
Some 450,000 cubic metres of wastewater leaked from the pipeline on February 7, though the mine says all of that water flowed directly into the same containment pond it was destined for in the first place.
Both Diavik staff and GNWT inspectors say there was no release of any contaminant into the wider environment beyond the pond.
Even so, the NWT government took the unusual step of publicly reporting the spill in a news release on Tuesday morning, a week after it was first notified by the mine and five days after the leak was belatedly registered on the territory’s spills database, more than a month after it occurred.
How spills are reported to the public has become a national talking point after seepage and a major spill at Imperial Oil’s Kearl facility, in northern Alberta, went unreported for months.
In this instance, Diavik says its staff did not initially think the spill was reportable because the leak never left the pond.
In a statement on Tuesday afternoon, the mine reiterated that the leak “was fully contained and at no stage was there any release into Lac De Gras or the environment.”
A Diavik spokesperson said by email the mine is “taking this situation seriously and will ensure such incidents get reported within the required timeframes.”
The North Inlet containment pond, into which the leaked wastewater flowed from the pipe, “includes an active water treatment plant,” Diavik stated. The wastewater is understood to include groundwater mixed with water used for dust suppression and drilling.
The temperature at Diavik is not expected to exceed -20C in the next week, with overnight lows closer to -30C.
The pipeline cannot be repaired “until extreme weather ceases and safe access can be established,” the mine stated.
In the meantime, an “alternate location” within the North Inlet facility is being used.
Meanwhile, the NWT government’s Department of Lands has clarified exactly when it was made aware of the leak.
On Tuesday afternoon, the department said inspectors were notified on March 14, two days before the spill was entered into the public database. Inspectors travelled to Diavik on March 15, the department said by email, after which communications staff were notified and Tuesday’s press release drawn up.
This isn’t the only spill on Diavik’s radar.
The company on Tuesday confirmed a new leak had been detected on Sunday on the dewatering line of the mine’s A21 pit. Diavik blamed “the failure of a valve which allowed water to overflow onto a road.”
All of that water has been contained “within the roadway area and none has left site,” Diavik stated.
“The incident was reported to the regulator within the appropriate timeframe and is currently under investigation. In the meantime, pumping ceased from A21 and the pipeline was inspected to ensure no further leaks were detected.”