Rio Tinto Ltd subsidiary Energy Resources of Australia Ltd (ERA) has achieved a record full year earnings result on the back of higher revenue from uranium sales.

ERA, which operates the Ranger mine in the Northern Territory, said on Friday net profit for calendar 2009 was $272.6 million, up 23 per cent from $221.8 million in 2008.

But it also warned its 2010 earnings would be adversely impacted by higher spending on planned maintenance and expenditure on development projects.

Revenue from sales of uranium oxide in 2009 rose by 55 per cent to a record $767.8 million, from $495.6 million previously, mostly due to an increase in the average realised sales price.

The miner realised an average sales price of $US50.84 per pound in 2009, up from $US32.53 per pound in 2008.

While its full year production was down two per cent at 5,240 tonnes, sales totalled 5,497 tonnes, up from 5,272 tonnes for the prior year.

The miner said its processing plant achieved consistently strong performance through the year.

ERA said production, sales volumes and average realised sales prices in 2010 were likely to be broadly similar to 2009.

The results would weighted to the second half as an effect of mine sequencing, lower grades and scheduled maintenance at the processing plant in the first half, the miner said.

Chief executive Rob Atkinson said the planned maintenance applied to truck fleet and power station engines, and a calciner in the processing plant.

"The other element (lifting costs) is as the mine gets deeper, haul distances get longer and you have to move typically more waste to get to the ore as well," Mr Atkinson told AAP.

He said substantial funds were earmarked for development including ERA's mine expansion project, which is focused on exploiting the Ranger 3 Deeps orebody.

"We certainly expect the spend ... to significantly increase in 2010, not only on our expansion project at Ranger 3 Deeps but also at other capital projects such as building a new accommodation plant and building evaporation ponds to treat process water."

The new accommodation plant was required to house an estimated 500 contract workers - about double Ranger's current workforce - who will work on a proposed heap leach facility, Mr Atkinson said.

He also said the nearby Jabiluka project, also owned by ERA, was "still a very, very important asset" but no progress had been made in terms of gaining permission from traditional owners to mine it.

"We've got a very firm established agreement with the traditional owners and will not mine it without their express permission," he said.

"Since that agreement was signed several years ago, there hasn't been any change to that."

The Mirrar people led a blockade to stop construction of the mine in 1998.

ERA's then-parent company North Ltd, which was bought by Rio Tinto, said Jabiluka would not be developed until Ranger is mined out.

The Ranger mine currently is expected to continue producing until 2020.

But Mr Atkinson said Jabiluka "isn't tied to Ranger at all".

ERA declared a final dividend of 25 cents per share, up from 20 cents in 2008.

The total dividends payable to shareholders for 2009 was 39 cents per share, up from 28 cents in 2008.

Shares in ERA closed seven cents higher at $20.95 on Friday.