The new HPAL projects, and the surge of inexpensive metal from a country whose deposits have long been unloved by major producers, could push the market into oversupply.
A video showing nine Congolese miners unexpectedly popping out of a collapsed gold mine and tumbling down a steep slope as onlookers cry out in joy has gone viral.
The investment community has turned net short of CME copper for the first time in five months, while funds have cut their long exposure on the London Metal Exchange.