Resource boost at Swedish deposit
22 August 2011
Uranium resources at the Haggan deposit in Sweden have more than doubled, making it the third largest undeveloped uranium resource in the world, according to Australia's Aura Energy.
.bmp "Haggan drilling (Aura)") |
| Summer drilling at Haggan (Image: Aura) |
The company said that JORC-compliant inferred resources have been upgraded from 291 million pounds U
3O
8 (111,930 tU) to 631 million pounds U
3O
8 (242,710 tU) at a grade of 160 ppm U
3O
8. The resources estimate includes, for the first time, the western section of the core permit area.
According to Aura, this resource places Haggan as the world’s third largest undeveloped uranium resource, after Continental's Viken project (with a resource of 1047 million pounds U3O8 (402,725 tU)), also in Sweden, and ARMZ's Elkon project in Russia (705 million pounds U3O8 (271,175 tU)).
The Haggan project, previously known as Storsjon, forms part of a large uranium field in central Sweden. The uranium occurs with molybdenum, nickel, vanadium and zinc in black shales. Aura said that the project contains 580,000 tonnes of nickel, as well as 383,000 tonnes of molybdenum. The company said that drilling used to derive the resource figures has only covered 15% of its permit areas at Haggan.
Conventional acid leach recoveries of up to 93% have been reported for uranium from Haggan. However, the high sulphur content of the deposit prompted Aura to look into bioleaching technologies, where bacteria are used to acidify and oxidise ores. A year ago, Aura said this may be technically feasible. Initial work had shown that the presence of bacteria improves extraction rates for uranium, molybdenum, nickel and zinc from the alum shale deposit.
Aura recently reported that the second phase of its bioleach testwork on the Haggan deposit has provided "highly encouraging" results. Chemical analysis and testwork have shown that the mineralization is acid-generating, facilitating metal leaching. Initial small-scale column leach tests have indicated up to 75% uranium extraction, it said. Significant extraction of other metals had also been achieved: nickel up to 65%, zinc to 60% and molybdenum to 25%. Aura said that there is "considerable scope for increasing these extractions," for example, by crushing the ore to a finer size.
Researched and written
by World Nuclear News