The ratings agency research arm suggested technology and productivity advances could effectively combat long-term cost increases from declining average grades, and higher material movement requirements, to maintain output rates at some mines.

New projects in Australia and the Americas (and, potentially, Africa) could lift mine supply from 20.3 million tonnes in 2020 to 26.8Mt by the end of the decade, Fitch said.

In Chile, Fitch sees production rising 0.5% this year to 5.89Mt, led by the ramp-up of BHP's Spence growth project in the second half, as well as increasing production at Lundin Mining's Candelaria mine and from mines hampered by heavy rains at the start of 2019.

While not yet factoring in Peru's lock-down on travel and other movements in response to COVID-19, Fitch revised down its forecast for Peru's copper production growth from 1% year-on-year in 2020 to zero growth on the back of lower production guidance for MMG's Las Bambas operation, and reduced output at the jointly owned Antamina mine, offset to some degree by Minsur's start-up at Mina Justa to begin late this year, "which will help to prevent a contraction in Peru's mine copper output".

Chinese copper production is expected to increase at an average 1.8% per annum over 2019-2028, compared with average annual 6.9% growth over the past decade. This slowdown in production growth will be driven by closures of low-grade copper mines and delayed planned capacity expansions.

Fitch expects Chinese copper miners to remain committed to investing in copper deposits abroad to secure access to raw material, exemplified by Zijin Mining's October US$146 million investment in Ivanhoe Mining, making it the second largest shareholder in the company developing the Kamoa-Kakula copper mine in the Democratic Republic of Congo.

In the US, Fitch expects 2020 growth of 2% as Nevada Copper's Pumpkin Hollow ramps up production.

"Despite pressure on profit margins as spot copper prices remain lower than expected, US miners are positioning themselves for long-term recovery in global copper demand," it said.

Canada hosts some of the largest development projects in the global pipeline, including Seabridge Gold's KSM and Teck Resources' Galore Creek projects in British Columbia, and MMG's Izok Corridor project in Nunavut.

As for the DRC, Fitch revised the 2020 outlook from 8% growth to a 15% contraction after Glencore put the Mutanda mine, which produced nearly 200,000t of copper and 27,000t of cobalt per annum, on care and maintenance in November.