RELATIONS have thawed between historical enemies Gundjeihmi Aboriginal Corporation and Kakadu uranium miner ERA.

The two groups issued their ever first joint statement this month on water management issues.

Gundjeihmi, which represents traditional land owners the Mirarr people, and ERA have agreed on a new surface water study for Ranger uranium mine and the decommissioning of a water management pond at the Jabiluka lease nearby.

The two groups had been at loggerheads over ERA's past attempts to mine the Jabiluka uranium deposit, environmental concerns at Ranger and a proposed acid heap leaching plant.

The conflict peaked in 1998 with a blockade protest at Jabiluka where thousands of protestors camped in Kakadu and hundreds were arrested including senior tradional owner Yvonne Margarula who was arrested for trespassing on her own land.

ERA chief executive Rob Atkinson said after 30 years of conflict it was a significant first step in improving relations.

"It's certainly the first joint media statement and that's an achievement in itself," he said.

"We've been working very, very hard to do things that are important to ... the traditional owners," Mr Atkinson said.

Good relations with the Gundjeihmi Aboriginal Corporation is crucial for ERA's plans to expand the Ranger mine with the Ranger 3 Deeps extension.

There is an estimated 34,000 tonnes of uranium in the new resource but it won't be extracted without the support of the traditional owners.

ERA is now negotiating a new mining agreement with them.

"It's certainly in the final stages," Mr Atkinson said.

"I think we're very very close to finally signing off and agreeing on that."

Work on a $120 million exploratory tunnel to map the resource is set to begin in May.

Analyst firm UBS has valued ERA at $2.87 per share if Ranger 3 Deeps goes ahead but only 67c per share if it doesn't.

The shares closed yesterday at $1.24.