North Perth-based Aura Energy Ltd has lodged applicaitons for a 64 kmsq landholding in one of Sweden's major uranium provinces, the company announced today.
North Perth-based Aura Energy Ltd has lodged applicaitons for a 64 kmsq landholding in one of Sweden's major uranium provinces, the company announced today.
The full text of a company announcement is pasted below
Aura Energy Ltd (ASX Code: AEE) has lodged applications for a significant landholding in one of the world's major uranium provinces in Sweden.
The Alum Shale Formation of Scandinavia is regarded as the largest known uranium resource in Europe. The shale is widely distributed throughout the Baltic States. The Swedish section contains exceptionally large resources of uranium, vanadium, molybdenum and nickel.
Aura has applied to the Bergsstaten (Swedish Mines Inspectorate) for five exploration licences in Jämtland, a county in the centre of Sweden adjoining the Norwegian border.
Aura applications cover 64 square kilometres of outcropping and near-surface Alum Shale, where it would be amenable to open pit mining.
The Swedish Geological Survey ("SGU") carried out extensive exploration in the area of Alum Shale south of Östersund in the 1970's and early 1980's. The SGU drilled 28 vertical diamond drill holes in an area of about 250 square kilometres. The drill holes were radiometrically logged and mineralised sections were analysed for molybdenum, vanadium, uranium and organic carbon. The results of this drilling in the vicinity of Aura's applications are given in the figures below.
Although no previous drilling has been completed in the areas that Aura has applied for, a number of outcrops plus the continuity of geology in nearby drill holes led the SGU to conclude that the Alum Shale host rocks continue into the applications.
Nuclear power is a very important power source for Sweden, with ten nuclear reactors providing approximately 50% of the country's electricity.
Aura's exploration and evaluation programme
Aura's proposed exploration in its licence application areas will focus on establishing the distribution of the Alum Shale and defining those areas where the higher grade uranium, molybdenum and vanadium shales are located. Consequently the initial programmes will be drilling based.
A programme to investigate the options available for extracting uranium and other metals will start when sample material is available.
The regional centre of Östersund is within 30kilometres of all the Aura applications and the area has good access roads.
Aura's strategy has been to acquire a substantial landholding of shales with uranium content of 200ppm U and 400ppm Mo, with other credits from nickel and vanadium. These higher grades occur in a particular unit at or near the top of the shale sequence, above thicker sequences that contain lower grades of the metals. The higher grade zone is up to 20m in thickness.
Comparison with other deposit types
The grades of uranium in the Alum Shale are similar to the alaskite-type deposits found at Rossing in Namibia. For example, the Bannerman Resources' Wel Witchia Project has an inferred resource of 27 million pounds at 186ppm U, and Forsys Metals' Valencia deposit has a quoted resource of 34 million pounds at 187 ppm U.
The Alum Shale grades are comparable with the lower part of the range of grades for large calcrete deposits such as Trekoppje in Namibia and Lake Maitland in Western Australia.
The advantage that the Alum Shale resources have over the Rossing and calcrete deposits is the presence of other metals. Credits from molybdenum, vanadium and nickel can double the in-ground value of the contained metals.
Background geography
The Cambrian stratigraphy of the Östersund district comprises black shales interlayered with subordinate quartzites, clean and bituminous limestones. These are overlain in parts of the project area by Ordovician limestones.
The Alum Shale is a mud and clay sedimentary rock that formed widely in northern Europe during the Cambrian period approximately 570 to 500 million years ago. The shale often contains organic carbon.
The Alum Shales are remarkable for their content of a number of metals, including uranium, vanadium, molybdenum, nickel and rare earth elements. These elements do not necessarily occur together, but Aura has focused its tenement acquisition in the Östersund area, where uranium, vanadium and molybdenum are relatively high.
The highland region of Scandinavia experienced major tectonic disruption in the Caledonide orogenic event. Rocks have been thrust from west to east and Alum Shale occurs both in its original position (in situ or autochthonous), and also in thrust sheets which came from the west (allochthonous). This can be particularly positive for the amount of Alum Shale present in any single area, giving repeated stacking of the same unit, and in places quadrupling the amount of shale present.
In the Aura application areas, the Alum Shale is either outcropping or lies under thin limestone cover.
Past uranium production from the Alum Shale
The Alum Shale has been mined as a source of uranium in the post-war period in both Sweden and Estonia, a Baltic state southeast of Sweden.
An operation to extract uranium from the Alum Shale began at Kvarntorp in southern Sweden in 1965. 400,000-500,000 tonnes of ore were mined per annum; the plant had a nominal capacity of 120 tonnes of uranium per year.
The plant operated for 5 years before closure because of low uranium prices. Recoveries of uranium in the plant were 80% at closure.
Uranium production from the Alum Shales began in Estonia in 1948, and the plant ran for several decades processing both Alum Shale and other uranium ores.