Territory uranium miner Energy Resources of Australia will finish extracting yellowcake early.

It had been due to finish mining Pit Three by Christmas but instead will finish this month as all in-situ reserves have been removed.

Backfilling of 30 million tonnes of soil will immediately being as part of the company's rehabilitation program to prepare the pit for tailings storage.

ERA has reduced its earnings forecast, saying it will report a full year loss of $155 million instead of the $135 million previously estimated.

It expects to produce between 3500 and 3700 tonnes of uranium oxide in 2012.

Chief executive Rob Atkinson said construction of the Ranger 3 Deeps exploration decline was on time and on budget, and the Ranger 3 Deeps mine pre-feasibility study was progressing well.

The mining company had 591 workers, including 102 indigenous employees, as of October 31.

The spot price of uranium has fallen from highs of more than $US100 per pound in 2007 to $US41 ($39.20) today, making it harder for producers to remain profitable.