Fresnillo, which mines gold and silver in Mexico, said silver output dropped last month mainly due to lower grades of ore and lower ore throughput.

The United States has half of the world's 18 large-scale CCS (carbon capture and storage) projects.

Tanzania will start cancelling inactive mining exploration licences and distribute the acreage to artisanal miners who are able to immediately commence activity in the area.

The news has rattled foreign investors already nervous governments in central African countries are seeking a much bigger share of resource revenues.

The possible collapse of British Steel comes after Germany's Thyssenkrupp and India's Tata Steel ditched a plan this month to merge their European steel assets to create the EU's second largest steelmaker after ArcelorMittal.

The blockade would be resumed pending further response from the miner and the central government.

The news comes a day after Zambia said it planned to strip Vedanta-controlled Konkola Copper Mines of its mining licence for breaching deal terms.

The fortunes of two commodities are beholden to China, the world's biggest importer and user of both iron ore and copper.

The LME nickel market was last week gripped by the most acute tightness in a decade.

The plant, a key supplier to the aluminium industry, currently operates at half of its capacity after a spill in February 2018.

The company fired about half of the underground workers at its Mototolo mine following an illegal strike.

London-listed Vedanta said in a statement that it was seeking an urgent meeting with Lungu over the future of KCM.