Rio Tinto’s $5.3 billion underground expansion of Oyu Tolgoi mine in Mongolia will increase its output in about four years time when the copper market is in deficit. Work on the project will begin from the middle of this year and first production from the underground mine is expected in 2020. When the operation is fully ramped up in 2027, Oyu Tolgoi is expected to produce more than 500,000 metric tons of copper a year.
