Turquoise Hill Resources Ltd. registered year-over-year declines in production from the Oyu Tolgoi copper-gold mine in Mongolia during the third quarter.

The company's copper in concentrates production dropped to 36,900 tonnes in the period from 46,600 tonnes a year-ago, according to Oct. 16 results.

Gold in concentrates production fell to 31,000 ounces from 37,000 ounces, while silver in concentrates production declined to 239,000 ounces compared to 361,000 ounces produced a year earlier.

Sales of copper in concentrates came in lower at 36,900 tonnes compared to 45,700 tonnes in the year-ago corresponding period, while gold and silver in concentrates sales reached 29,000 ounces and 229,000 ounces, down from 38,000 ounces and 341,000 ounces, respectively, on a yearly basis.

The company noted that it plans to mine open-pit operations in phase four and six during the year, while stockpiled ore will continue to be processed this year.

Oyu Tolgoi's full-year production guidance remains unchanged at 130,000 tonnes to 160,000 tonnes of copper and 100,000 ounces to 140,000 ounces of gold in concentrates.