Rio Tinto delays start of Oyu Tolgoi expansion due to technical issues

World’s No.2 miner Rio Tinto (ASX, LON, NYSE:RIO) said Tuesday it will likely have to delay first production from the $5.3 billion underground expansion of its Oyu Tolgoi copper-gold-silver mine in Mongolia, originally scheduled for early 2020. Delivering third-quarter results, the...