By Divya Rajagopal and Mrinalika Roy

TORONTO (Reuters) -Rio Tinto and Teck Resources (NYSE:) said on Thursday the labor dispute between Canada’s two biggest railway companies and their workers would likely disrupt their operations and the miners were taking steps to mitigate the damage.

A Rio Tinto (NYSE:) spokesperson said the company’s contingency plans to minimize the impact included trucking certain materials and products and increasing use of its own rail network.

Teck said it was looking to use alternative transportation, without specifying. A spokesperson added that the interruption of rail service is negative for its partners and customers in the critical minerals supply chain.

Canada’s top two railroads, Canadian National Railway (TSX:) and Canadian Pacific (NYSE:) Kansas City locked out more than 9,000 unionized workers on Thursday, triggering an unprecedented rail stoppage that threatens to cause billions of dollars worth of economic damage and disrupt North American supply chains.

Rio Tinto’s Canadian operations include production of iron ore, aluminum and diamonds. Canadian operations contributed $800 million to the company’s total revenue of $26.8 billion in the first half of 2024.

The lockout will be mostly felt in the iron ore and aluminum businesses, Rio Tinto said. It owns around 100 kilometres (62 miles) of railway for its aluminum operations and 400 kilometres of rail network for iron ore.

Teck’s Canadian operations include and molybdenum production at its Highland Valley, British Columbia mine, as well as zinc and lead smelting and refining at Trail, British Columbia.