London: 18January 2007 - The directors of Agricola Resources plc ("Agricola") are pleased to announce that complete results have been received of an extensive radon soil survey over a regional area adjacent to the Paukkajanvaara mine, located north of town of Eno in the Eastern Finland County.
The sensor cups used were Alpha Track Detectors, which were delivered and analysed by the Alphatrack laboratory, Vancouver, Canada. (www.alphatrack.ca). These detectors facilitate the identification of buried uranium deposits that have no surface radiometric expression.
A total of 490 sensor cups were placed in holes dug in the soils along selected minor trails and bush roads, which are crosscutting potentially geological structures of the region several kilometres away from the mine site. The spacing of the detectors was generally 25 m. Closer spacing was used at some targets previously identified at a radon survey by Agricola in 2005. Reference cups were also placed on the mine site, which since the 1970s has been covered by thick soil and revegitated. At each sample site a sensor cup was placed in a dug out hole in the soil at about 50-75 cm depth. The hole with the sensor cup at the bottom was refilled with soil. After a sensor reacting time of 30 days the cups were retrieved, sealed and sent for radon analysis at the laboratory in Vancouver, Canada.
The results shows that at least four larger areas can be identified with potential interest for new uranium discoveries outside the immediate mine area.
One of these areas was already identified in the radon survey in 2005 but more detailed sampling in the present survey has better defined this target area (no. 4). Three areas (2, 3 and 5) indicate further new target zones for uranium. The most prominent of these is a more than 700 m long radon anomaly area (2) in the north parts of the survey area, comprised of several high reading radon samples along a north-south striking gentle hill north of a minor lake Iso-Saerkilampi extending north towards a road crossing with a minor bay Piilolahti. The geological structures and bedrock types at this local area are of similar type as those at the Paukkajanvaara uranium mine, which is located about four kilometres to the south. By detailed interpretation of the data from the closely sampled lines at this area (2) future drill sites to test the presence of uranium mineralisation can already be selected. Target area 3 located immediately to the east is of similar type but of lower magnitude as that of area (2). Area (5) is located south of the Ylae-Paukkaja lake about two kilometres to the south of the Paukkajanvaara mine. This anomaly may indicate a direct southern extension of the uranium bearing horizons from the mine site. Area (1) is located on the actual mine site area, which has been found to be well responding by this radon exploration technique. There are however indications of direct extension of the uranium mineralisation further towards north.
The objective of the survey is to pinpoint new targets and extensions of potential mine structures for an early drilling campaign in the area. Additional radon surveys and drilling are planned.
The present soil radon survey forms part of the Agricola/Cooper joint venture agreement previously announced.
Contact :
Dr. Robert Young, Chairman
Agricola Resources plc
Tel: +44 (0) 1353 649 701
Technical background:
The use of radon gas detectors to identify uranium mineralisation is well known and has been in use since the 1960s. Because radon is a gas, it has much greater mobility than uranium and radium, which are fixed in the solid matter in rocks and soils. Radon migrates to the surface by escaping into fractures and openings and into the pore spaces between grains of soil. The ease and efficiency with which radon moves in the pore space or fracture effects how much radon is detected at the surface. If radon is able to move easily in the pore space, then it can travel a great distance before it decays, and is therefore detectable at the surface above a uranium occurrence.
The Alpha Track method uses a small cellulose-nitrate film attached to the inner side of a 0.5 litre size plastic sample cup. The film is not affected by light or any other form of electromagnetic radiation. The film is only sensitive to alpha particles emitted by daugther products of uranium (mainly radon).
The Alpha Track Detectors are buried in holes dug in the soil to approximately 50-75 cms depth. The holes are then tightly filled with soil and left in place for 30 days after which they were retrieved and returned to Alpha Track for processing. The processing of the detectors entails the etching of the nitro-cellulose film. This etching processes highlights the imprints caused by the alpha particles when they impinge on the film. The tracks are counted optically and expressed as "Track count per square millimetre (T/mm2)". These counts are proportional to the radon gas levels at the sample site.
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