VANCOUVER (miningweekly.com) – Rio Tinto subsidiary Turquoise Hill Resources has reported a 23% drop in concentrate production at the Oyu Tolgoi copper/gold mine, in Mongolia, as it processed lower grades from phases 6 and early 4A of the openpit, as well as stockpile material, during the three months ended March.
Concentrate production slumped to 176 000 t in the period, in line with expectations, offset by the concentrator recording record throughput on the back of benefit from earlier productivity improvements, Turquoise Hill CEO Jeff Tygesen stated on Wednesday.
During the quarter, openpit operations focused mainly on Phase 6, which has higher copper grades but relatively low gold grades. Ore treated during the period increased 2.7% over the prior period, and average daily throughput of 112 100 t for the first quarter increased by 5.1% over the December quarter.
Copper output for the quarter decreased 16.3% quarter-on-quarter to 38 100 t and gold output fell 49% over the prior comparable period to 25 000 oz owing to lower grades, with recoveries at the lower end of the grade recovery curve.
Oyu Tolgoi is expected to produce 130 000 t to 160 000 t of copper and 100 000 oz to 140 000 oz of gold in concentrates for 2017.
Rio Tinto operates the Oyu Tolgoi copper/gold mine, which is 66% owned by its Turquoise Hill arm and 34% owned by the Mongolian government.