PERTH (miningweekly.com) – Diversified major Rio Tinto has reported increased production across its iron-ore and coal assets, but has adjusted its copper output expectations for the full year on the back of delays at the Escondida operation.

“The business performed very well in the September quarter, with a strong quarterly production performance and a wave of productivity improvements embedded through our operations,” CEO Jean-Sebastian Jacques said on Tuesday.

“In particular, we are making good progress with further improvements to our world-class Pilbara iron-ore business, including the opening of the Silvergrass mine and the implementation of AutoHaul.”

Iron-ore production in the third quarter ended September reached 85-million tonnes, which was up by 6% on the previous quarter, reflecting productivity enhancement projects across most of the company’s operations in the Pilbara.

In the nine months to date, the Pilbara mines delivered 241.9-million tonnes, with Rio’s share of production reaching 198.4-million tonnes, which was 1% lower than the previous corresponding period, owing mainly to weather disruptions in the first half of the year.

The group maintained its iron-ore full year guidance of about 330-million tonnes on a 100% basis. Earlier in the year, Rio Tinto had hoped to ship between 330-million and 340-million tonnes, but the miner revised its guidance after a sluggish first-half performance.

Meanwhile, hard coking coal production in the September quarter was up by 44% on the second quarter, to 2.2-million tonnes, as operations normalised at the Hall Creek operation, in Queensland, following the impact of Cyclone Debbie earlier this year.

Semi-soft coking coal and thermal coal production declined by 28% and 23%, respectively, between the second and third quarters, following the sale of Rio subsidiary Coal & Allied to ASX-listed Yancoal Australia.

During the quarter under review, mined copper production was down 3% on the previous quarter, to 120 600 t, as lower copper head grades affected production at the Kennecott operation, in the US, and the Oyu Tolgoi mine, in Mongolia.

Mined copper production at Escondida, in Chile, increased by 21% during the quarter, following a return to normal production after a union strike. However, Rio noted that as a consequence of the strike action in the first quarter of 2017, the commissioning of the Los Colorados extension had been delayed, which caused the company to amend its full-year copper guidance from between 500 000 t and 550 000 t, to between 460 000 t and 480 000 t.

Meanwhile, Rio reported that bauxite production for the third quarter remained stable at 12.8-million tonnes, while aluminium production was also stagnant at 887 000 t, compared with the second quarter.

Jacques said on Tuesday that the company continued to shape its asset portfolio, announcing A$2.5-billion of additional returns to shareholders during the September quarter, from proceeds of the Coal & Allied sale.

He said that the return of capital demonstrated the robustness of the group’s strategy and ability to invest in high-value growth, while returning excess cash to shareholders.

“We have announced over A$8-billion of cash returns in 2017. Our relentless focus on cash generation and disciplined capital allocation will continue to deliver superior returns for our shareholders,” he added.