Power cuts in north-western Zambia, Africa's second-biggest copper producer, have affected production at mines run by Canada's First Quantum Minerals and Barrick Gold, an industry body said on Tuesday.
Zambian power utility Zesco Ltd is limiting power it supplies to customers, including mining companies, after water levels at its hydro-electric plants dropped due to drought.
"Power was reduced to both First Quantum Minerals and Lumwana over the weekend," Jackson Sikamo, President of the Zambian Chamber of Mines said.
Lumwana is Barrick's open-pit copper mine.
First Quantum said in a statement its Kansanshi mine, smelter and its greenfield Sentinel project were running at reduced capacities.
"Various options to alleviate the effect on production are being evaluated," the company said in a statement released on Monday.
First Quantum said it was unable to provide estimates on how long the power supply reduction would last or its impact on production.
First Quantum's Zambian smelter, which ramped up in February, is expected to produce over 300,000 tonnes of copper metal from around 1.2 million tonnes of concentrate a year, when it reaches full operation.
Zesco has hired independent power producers to procure more electricity by the end of 2015, First Quantum said.
Supply to the mineral-rich Copperbelt province was not affected, Sikamo said, adding that power cuts were imminent.
An industry source Zesco said Copperbelt Energy Corp, which buys electricity in bulk and supplies it to mines in the Copperbelt province, would slash power by as much as 25 percent.
Other foreign companies running mines in the southern African nation include Glencore, Impala Platinum and Vedanta Resources.