Jabiru airport recorded the highest December rainfall ever at 459mm and rainfall between September 1 and yesterday was close to reaching 2010-11’s levels, which prompted ERA to temporarily suspend processing between January and June last year.

As a result, the company has been unable to fully dewater Pit 3 and access to high-grade ore at the bottom of the pit will be delayed.

ERA said the delay could impact production for 2012, though it is uncertain as to what extent.

The company said it would provide further guidance in its full-year results.

Meanwhile, 2011 full-year production was down 30% on 2010 to 2641 tonnes of uranium oxide, but was within the company’s guidance of 2600t.

December was a reasonable quarter for the company, with material mined jumping 38% to 3.73 million tonnes and ore mined soaring 157% to 673,000t on the previous quarter.

Ore milled rose 1% to 685,000t and mill recovery rose 2% to 88.6%. Fourth quarter production was 1030t, up 2% on the September quarter.

During the quarter, the company completed a 4m lift to the tailings storage facility with approval received for an increased wet season maximum operating level of 56m.

Evaluation expenditure was $A4.6 million for the quarter and $18 million for the year.

Exploration expenditure was $4.5 million for the quarter and $9 million for the year with recent exploration in the Georgetown failing to intersect consistent mineralisation.

Work will begin on the box cut for the $120 million Ranger 3 Deeps exploration decline in May.

Shares in ERA, which are 80.6%-owned by Rio Tinto, jumped 6% or 7c to $1.25.