Rio Tinto has shipped a record 78 million tonnes of iron ore during the September quarter.

The world’s second largest miner is selling more iron ore than it is producing, with production of 76.8 million tonnes also a record.

The company maintained guidance for iron ore shipments of 300 million tonnes in 2014 and production of 295 million tonnes.

The iron ore result missed some analysts’ expectations.

Deutsche Bank had estimated production of 78.1 million tonnes.

RBC Capital Markets had forecast Rio’s share of production – excluding joint venture partners – would lift by 11 per cent to 64 million tonnes, but the actual number was only a five per cent rise, to 60.5 million tonnes.

Rio did not comment on the current volatility in the iron ore price, with the company on track to incur a fall of about 30 per cent in realised prices this year.

However, the copper production result was far better than expected. It was down eight per cent on the second quarter, following well flagged maintenance at its US Bingham mine and operational issues at Oyu Tolgoi in Mongolia.

But, at 151.8 million tonnes, it was up one per cent on the previous third quarter and up 15 per cent over the nine-month period compared with the same period the prior year.

Consequently, Rio is increasing its copper guidance from 585,000 mined tonnes to 615,000 and 260,000 refined tonnes to 300,000 driven by improved recoveries at the US mine and the sustained ramp up at Oyu Tolgoi.

Both thermal and coking coal production was well ahead of expectations.

Falls of 20 per cent plus were expected but hard coking coal was down only 14 per cent on 2013 to 1.9 million tonnes while semi-soft and thermal coal declined 13 per cent to 6.1 million tonnes.

The loss of production from the Clermont mine which was sold to Glencore has been offset by production of thermal coal from Hail Creek and significant productivity gains achieved across other coal mines, Rio said.

Global bauxite production was three per cent weaker on last year at 10.9 million tonnes while aluminium production of 848,000 tonnes was in line with last year.

Rio Tinto chief executive Sam Walsh said the company had delivered a strong quarter.

“Our strategy of focusing on long-life, low-cost assets means we will continue to generate strong cash flows despite a lower price environment, resulting in materially increased and consistent cash returns to shareholders,” he said.

The infrastructure for Rio’s iron ore expansion to 360 million tonnes a year was 75 per cent complete, with all rail, marine and wharf works in place.