Rio Tinto Ltd/Plc's first-quarter aluminum output fell 6 percent, mostly due to curtailments in Europe, as the world's biggest producer attempted to better balance supply with sinking global demand from industrial sectors, the company said on Wednesday.

Rio also produced 2 percent less alumina, 15 percent less iron ore but 33 percent more refined copper in the first quarter versus the same period a year ago, it said.

We were expecting it to be soft but it was softer than we thought, UBS mining analyst Glyn Lawcock said.

Obviously some of the curtailments that they have announced have come through quite quickly so all divisions were a little bit weaker than we thought except for copper and iron ore, he said.

Rio's shares briefly reversed early gains and turned negative after the report, but recovered to stand 0.46 percent higher at A$57.00 at 0531 GMT (1:31 a.m. EDT).

For a graphic of recent production, see http://graphics.thomsonreuters.com/apr09/AU_RIOPRDQ109.jpg

Rio Tinto, the world's top aluminum maker since 2007 after buying Canada's Alcan, has proposed selling minority asset stakes and more equity to state-owned Chinese aluminum group Chinalco -- already its biggest shareholder -- to raise $19.5 billion to help weather the bust in commodities markets.

Markets remain volatile and the timing of global economic recovery uncertain, Rio Chief Executive Tom Albanese said in a statement. He said he sees Chinese steel demand recovering in the second half of 2009.

A decline in aluminum output was flagged earlier this year when Rio announced cuts to address a sharp drop in demand and pricing.

Over the quarter, a steady performance at the Canadian smelters was outweighed by production cutbacks in operations in Europe and at a smelter in New Zealand, the company said.

In iron ore, Albanese said the company was on track with earlier guidance to mine about 200 million tons globally in 2009 after reporting a 15 percent year-on-year first quarter decline in overall production.

First quarter iron ore shipments from the company's main Pilbara mines were slowed by 9 percent due flooding in the region over the period, which is the height of the cyclone season, the company said.

Canada Copper