Canadian union Unifor said on Sunday about 900 workers had started strike action at global miner Rio Tinto's operations in the western Canadian province of British Columbia.
Unifor issued a 72-hour strike notice on Wednesday after nearly seven weeks of unproductive talks over proposed changes to workers' retirement benefits and unresolved grievances.
"Rio Tinto was given every opportunity to reach a fair deal but showed complete disregard for our issues," the union said in a statement.
The union represents about 900 workers at the miner's aluminium smelting plant in Kitimat and power generating facility in Kemano.
Unifor said it was committed to resolving the labour dispute amicably and urged the mining company's management to reach a fair settlement.
Rio had earlier sought an order from the province's labour relations board declaring power plant workers essential, according to a union bulletin.
(Reporting by Rithika Krishna in Bengaluru and Jeff Lewis in Toronto Additional reporting by Radhika Anilkumar Editing by Mark Potter) ((Radhika.Anilkumar@thomsonreuters.com; +91 8067490824;))