However, the miner did manage to meet the bottom-end of upwardly revised 2021 production guidance of 90 million-100 million pounds of copper, and has set 2022 and 2023 guidance at 80Mlb-90Mlb and 90Mlb-105Mlb, respectively. 

"Production was impacted late in the fourth quarter by severe weather, including heavy rains and flooding in British Columbia, followed by unprecedented cold temperatures that caused extremely difficult operating conditions, in addition to damage sustained to our secondary crusher," the miner's president and CEO Gil Clausen said on February 14. 

As recently as December 6, Copper Mountain informed shareholders that up until that point, it had experienced no material impact due to the heavy rains. 

By the end of the December quarter, however, the flagship Copper Mountain Mines production for the three months was 16.7Mlb, which was down from 23.1Mlb for the same period a year earlier. 

That took Copper Mountain's full year production to 90.1Mlb of copper. 

"We came in right at the mid-point of our original guidance," Clausen said. 

BMO Capital Markets analyst Rene Cartier said that while the fourth-quarter copper production was some 18% below the investment bank's expectations, a key concern was the knock-on impact from the weather-related issues going into this year. Copper Mountain's guidance was, however, in line with BMO's estimates.

For 2022 and 2023, BMO forcasted 88Mlb and 91Mlb, respectively. 

"Given the aforementioned damage, mill throughput is expected at reduced levels of 35,000-38,000 tonnes per day through to mid-Q2/22; production is expected to be weighted to H2/22," Cartier noted. 

Copper Mountain also produced 5,472 ounces of gold and 80,377oz of silver in the December quarter, which compared with 8,959oz of gold and 144,934oz of silver a year earlier. 

Gold production was expected to be about 18,000-25,000oz in 2022 and silver production around 315,000-335,000oz, Copper Mountain said. 

The company traded at C$3.81/share on the Toronto Stock Exchange on February 14, which was down 8%. 

Copper Mountain has a market capitalisation of C$801.49 million.