Workers at BHP Billiton Ltd's Escondida mine in Chile, the world's biggest copper mine, have voted to reject a company wage offer and go on strike.

The Hope Diamond, a rare blue diamond that is one of the world's most famous jewels, has had a complicated history, passing through the hands of monarchs and bankers and heiresses and thieves. The geological history of blue diamonds is even more complex.

Canadian microbreweries are facing a shortage of cans and higher costs, forcing some to cut beer production after the country imposed retaliatory import duties on U.S. aluminum imports in the busy summer season.

The main union at Chile's Caserones mine has rejected operator Lumina Copper's final contract offer and workers have approved strike action.

A surplus of cobalt chemicals used to make the rechargeable batteries that power electric vehicles has seen Chinese refiners switch to producing metal, sending prices down 30 percent in recent months.

Alumina is having a turbulent year.

BHP Billiton last week agreed to sell its U.S. shale oil and gas assets for $10.5 billion, while Rio Tinto appears on track to exit its troubled investment in the giant Grasberg copper and gold mine in Indonesia for about $3.5 billion.

The unexplored areas that have significant potential output of copper, gold, phosphate and other minerals.

Union members have until Wednesday to finish voting on the company's proposal.

The miner said it aims to ensure a level of cash flow for its $6.3 billion Cobre Panama project ahead of commercial production.

Turkey was looking to boost its trade with West Africa and sub-Saharan countries, where there is demand for the less capital-intensive steel products.

Any revisions would need to be discussed with the coal and power industry beforehand, and any impacts on state revenue would need to be calculated.