Copper mining companies in Zambia, Africa’s second biggest copper producer, have seen a 30% drop in revenues over the three months to April, due to Covid-19 response measures. The post-pandemic disruption is now expected to last for another 12 months, the Chamber of Mines said on Thursday, Reuters reports.

The Chamber further elaborated that global lockdown measures have severely impacted the Zambian mining supply chains and impeded the export and sale of copper, hurting revenues and government coffers.

Royalty payments are estimated to have come in at $60-65m between February and April, about two-thirds of the $90m previously estimated.