Workers at Zaldivar are set to vote on a strike this week, while supervisors at Centinela mine have already decided it, but expect a government mediation mechanism to extend negotiations for at least five more days.
Dam restrictions in China following excessive rains are also reducing hydropower capacity there, including at the world's biggest power station, forcing utilities to ramp up output at coal-fired utilities.
U.S. Mint American Eagle gold coin sales in the first half of 2017 were the lowest for this period in a decade, while sales of silver in the period were the weakest since 2008, government data showed on Friday.
U.S. President Donald Trump's plan to restrict imports of steel and aluminium for national security reasons came under fire at the World Trade Organization on Friday, with China, the European Union, Brazil, Australia, Taiwan and Russia raising concerns.
The Tanzanian government submitted three bills to parliament on Thursday that would allow it to force mining and energy companies to renegotiate their contracts.
The funds from Beijing would contribute towards building 1,400 km of a planned 4,000 km railway network, which would connect bauxite mines and production sites.
Mining companies operating in Chile are examining restarting projects that were put on hold in recent years due to a copper price slump, the mining minister and industry executives said, though final investment decisions will wait until political uncertainty lifts after the November presidential elections.