The planned strike in the coal sector could affect power supply in Africa's most industrialized economy, as about 85 percent of electricity is generated from the fossil fuel.
Adjusted earnings before interest, taxation, depreciation and amortisation (EBITDA) rose 7 percent to $475m while total revenue grew 5 percent to $744m.
Armed separatists have occupied five villages in Indonesia’s Papua province, threatening to disrupt Freeport-McMoRan Inc’s giant Grasberg copper mine, which has already been hit this year by labor unrest and a dispute over operating rights.
Fatal accidents last week raised number of fatalities in 2017 to 76, above the 73 reported in 2016, South Africa’s Chamber of Mines said in a statement.
Production goals for Vale's Carajas project, the world's largest open-air iron ore mine, are directly tied to cargo shipments on its railroad there, which carries output to Brazil's Ponta da Madeira port.
The US' Commerce Department announced in April that it was probing imports of aluminum from China and elsewhere, blaming unfairly traded imports for causing several domestic smelters to close or halt production in recent years.