A wetter than average rainy season has prompted Energy Resources of Australia (ERA) to extend a temporary suspension of processing operations at the Ranger uranium mine through to the end of July.

Processing operations were suspended in late January as a precaution to ensure that levels in the plant's tailings storage facility remained below authorised limits throughout the wet season. The decision was made in anticipation that the extreme rainfall that had led to widespread flooding in northern and eastern Australia would continue, and the suspension was initially expected to last 12 weeks.

Since January, the Northern Territory has continued to receive rainfall significantly higher than the average. Indeed, the Ranger mine has seen its third highest wet season on record with a total of nearly 2.4 m of rain recorded between 1 September and 12 April, and there are still three weeks to go before the wet season officially ends.

Although the water level in the tailings storage facility is below the authorised operating limit, the total process water inventory at the site has recently exceeded the level at which operations can restart, ERA says. The company has therefore decided to extend the suspension of processing operations until late July to give the total water inventory time to reduce. The company warns that the decision is nevertheless highly dependent on future rainfall.
 
Furthermore, mining operations at Ranger have recently been suspended because of the large volume of water in the open pit mine, again a result of the unusually high rainfall. Although operations will resume in the upper levels when the water level recedes, ERA says it does not anticipate being able to access the high grade ore at the bottom of the mine until late 2011.
 
The suspension of the processing plant has had what ERA describes as a "significant" effect on its results for the first quarter of 2011, with total production of 518 tonnes U₃O₈ (439 tU) against 888 tonnes U₃O₈ (753 tU) in the first quarter of 2010. The company has revised its 2011 production forecast downwards from an expected 3793 tonnes U₃O₈ (3216 tU) to something in the region of 2400 tonnes U₃O₈ (2035 tU). About 4500 tonnes U₃O₈(3816 tU) of ERA's sales commitments will therefore have to be met by purchased material, although the company says it has already finalised a substantial portion of the necessary purchases.
 
ERA says it expects to report a net loss of A$30-50 million ($32-52 million) for the first half of 2011, compared to a net profit of A$22.7 million ($23.8 million) for the same period in 2010. The company is in the process of carrying out a comprehensive business review of all its current operations and future projects. Mining operations at the existing open pit are due to cease by the end of 2012, although ERA is processing a proposal to develop the underground Ranger 3 Deeps exploration area. A proposed heap leach facility to recover uranium from low grade ore is undergoing governmental reviews.