The Union of Northern Workers says Dominion Diamond Mines has rejected its proposals to resolve what the mine operator has termed an absenteeism problem at the Ekati mine.
The union filed two separate complaints regarding Dominion's warning, last month, that it may lay off 150 entry-level workers at the mine over the issue.
Dominion provided the union with data related to absenteeism earlier this month, though the union has since claimed the data was not detailed enough. Employees failing to turn up for work has been a concern for Dominion since at least early 2017.
The mine operator plans to move to contract workers by October 1, according to the union.
In a message to its members on Thursday, the union said proposals it submitted to Dominion – including a working group on approaches to resolving absenteeism, and preparatory work on Ekati's next collective agreement – "were outright refused."
A grievance filed with Dominion over Article 26 of the current collective agreement, which relates to contract work and layoffs, was also rejected by the company and will now be referred by the union to its parent, the Public Service Alliance of Canada, for arbitration.
In a statement to Cabin Radio, Dominion said: "Dominion Diamond Mines and the Union of Northern Workers are currently working to address the issue of absenteeism at Ekati. Therefore, neither party will be providing additional comments on the matter at this time."