The miner's 2009 output slipped 2 per cent to 5240 tonnes of uranium, the lowest in three years, after a period of mining higher-grade ore from the deposit ended, ERA said yesterday.

But the quarter's production made the Ranger mine, which started in 1981, the second mine in the world to produce 100,000 tonnes of uranium, after Rossing, Rio's Namibian subsidiary.

Fourth-quarter production was 1140 tonnes, down from 1408 tonnes in the third quarter and the lowest production for six quarters.

The drop in production did not surprise the market too much, after ERA late last year flagged full-year production would be in line with 2008, despite a strong first three quarters.

ERA's shares slipped 64c, or 2.8 per cent, to $22.27 yesterday. The company is 68.4 per cent-owned by Rio.

But ERA boosted 2009 realised uranium oxide sales price to $US50.84 a pound, up from $US32.53 in 2008, as more of its lower-priced contracts ended and it was able to replace them with higher-priced deals.

Uranium contracts are generally priced on a three to five-year basis, meaning ERA has only recently been able to reap the benefits of growing demand that sent spot prices from about $US10 a pound in 2003 to a peak near $US140 in 2007.

While less ore was mined at Ranger in the quarter, the company managed to boost the amount of ore put through its mill by 22 per cent, leading chief financial officer Steeve Thibeault to put a positive slant on the quarter.

"We have a very, very strong production report and performance, and the average realised price is a record, up 56 per cent on last year," Mr Thibeault said.

He said the outlook for the uranium market was "very positive", based on the growing preference for energy sources that limit the emissions of greenhouse gas.