Energy Resources of Australia Ltd (ASX:ERA) has posted an 82% drop in net profit to $22.7 million in the first half of 2010, compared with $127.6 million in same half last year.

The company, majority owned by Rio Tinto Ltd (ASX:RIO), says higher costs in maintenance and development affected the result, as well as a stronger Australian dollar.

ERA says due to delayed access to higher grade ore, this year’s production of uranium oxide is expected between 4,300 and 4,700 tonnes, lower than earlier annual guidance of 5,240 tonnes.

A 36% drop in uranium oxide sales was also recorded for the first half of 2010, down to $209.6 million, from the $336.1 million posted for the same half-yearly period in 2009.

Energy Resources says in the short term the uranium market appears well supplied, but in the long term higher spot and term prices can be expected.

Energy Resources reported a profit of $272.57 for the year ending 30 December 2009.