The company has blamed the slump on a fall in the price of uranium oxide and poor grades of ore at its Northern Territory mine.

ERA's net profit for the six months to the end of June fell to $22.7 million from $127.6 million for the same period last year.

Resources analyst Peter Strachan says it is natural for mines to go through lean times.

"It's very difficult to maintain a steady state over full year for the month by month, so some months they'll have the bonanza grade and other months they'll be digging through lower grade material to get to higher grade material," he said.

ERA chief executive Rob Atkinson says the profit plunge came after a boom year last year.

"It is a significant difference but we've got to remember that 2009 was a record year on many many fronts," he said.

"That we did produce more, and we did sell more and we had a higher price."