The US special presidential envoy for climate John Kerry is set to visit Vietnam next week and will travel to Mexico again before the UN climate summit in November.
The White House is eyeing three options: an outright ban, increasing tariffs to levels so punitive they would impose an effective ban, or sanctioning Rusal.
Some of the biggest copper mines in the world are turning to different ways to get their metal to port after an increase in train robberies spurred the suspension of rail services in northern Chile.
