Rio second-quarter refined copper output falls

SYDNEY (Reuters) - Global miner Rio Tinto's (RIO.AX) (RIO.L) second-quarter refined copper output tumbled 18 percent from the same period a year ago, facing lower yields at some operations, while production of iron ore, weighted toward sales in China, rose 13 percent, the company said on Wednesday.

"Chinese GDP is continuing to grow at around 10 percent per annum, demand is strong while supply remains constrained," Rio Chief Executive Tom Albanese said in a statement.

Rio Tinto, which late last year acquired Canadian aluminium group Alcan and is now fighting an unsolicited $145 billion (72 billion pound) all-share offer by larger rival BHP Billiton (BHP.AX)(BLT.L), said aluminium output rose nearly five-fold over the period but fell 1 percent versus the previous quarter.

Iron ore production jumped despite a major gas outage hitting the Pilbara mining region in Western Australia.

"Expansion projects remain on schedule and on budget despite challenges posed by the Apache outage and weather conditions," Rio Tinto said.

Output of bauxite and alumina, needed to make aluminium, was up 110 percent and 231 percent respectively.

Australian thermal and coking coal production was up 15 percent and 25 percent respectively, "recovering well from flooding set backs earlier in the year," Albanese said.

Record quarterly mined copper production was up 15 percent on the corresponding quarter, it said.

At its 30 percent-owned Chilean Escondida mine, the world's largest copper mine, Rio Tinto's share of mined copper rose 22 percent, though refined production suffered from trucking and shovelling curtailments.

(Reporting by James Regan, Editing by Sonali Paul)