Zambia's cobalt production also dropped to 247 tonnes last year from 316 tonnes a year earlier, according to the Zambia Statistics Agency (ZAMSTATS).
The Zambia Chamber of Mines said the reduced output was mainly due to operational challenges arising from a lack of recapitalisation due to an unattractive mining tax regime.
"It is only now that we are seeing mining companies recapitalising after mineral royalty was made a deductible expense," chamber chief executive Sokwani Chilembo told Reuters.
Mining companies operating in Zambia had long complained about what they called "double taxation", with mineral royalty payments not treated as a deductible expense when calculating corporate income tax since 2019.
(Reporting by Chris Mfula; Editing by Promit Mukherjee, Kirsten Donovan)