Copper production in Q1 stood at 13.3 million pounds, having dropped 10% from Q4 2021, and gold production of 13,610 ounces, was down by 11%, the company said.

Imperial noted that block cave mining is advancing with the exploration decline at 1,225 metres as of April 20 and related surface infrastructure development is expected to be "substantially" complete by June.

The feasibility study for the block cave is targeted to complete in June next year.

"Drilling continues to expand and define the East Ridge zone, which is located immediately east of the current development area," Imperial's president Brian Kynoch said, noting that it is developing into one of Red Chris' more significant zones of mineralisation.

"In the context of future development, the zone is strategically located close to the current active operating area and the advancing exploration decline passes near the zone, which will allow for easier access," he said.

Newcrest acquired 70% of the Red Chris operation in a joint venture with Imperial Metals in 2019 in a move aimed at entering North America with an asset with "significant" expansion potential.

Imperial's share price was quoted as C$3.64 (US$2.85) on April 28, giving the company a market capitalisation of C$514.68 million.