The Western Athabasca Projects are situated near the Carswell structure, a late Proterozoic, circular, probable meteorite impact structure. The Projects are underlain by basement rocks which straddle both the Clearwater and Lloyd Domains of the Western Craton in the western Canadian Shield. The Lloyd Domain comprises granitic gneiss with local pelitic gneiss units, the latter which are spatially associated with uranium mineralization on other projects in the area, such as Shea Creek and the Cluff Lake deposits. The Clearwater Domain comprises fine-grained, cumulative-layered leucogabbronorite and anorthosite which are concordantly interlayered with units of mafic garnetiferous tonalitic gneisses and heterogeneous felsic gneisses, and which are intruded by granites. The domain is characterized by a prominent regional magnetic, medium to high, broad north-northeast trending linear that is associated with a regional gravity low. Basement rocks of the Lloyd and Clearwater Domains are unconformably overlain by approximately 130 to 730 metres of Athabasca Group sandstone and, in the southern parts of the property, Devonian-age limestone and Cretaceous-age Mannville Group sediments comprised of coaly sandstone and siltstones.
Exploration on the Western Athabasca Projects is at an early stage. To date, airborne and ground geophysical surveys and drilling in widely spaced diamond drill holes have been completed. First-pass airborne exploration programs that included MEGATEM(r) and Falcon(r) Gravity Gradiometer airborne surveys were flown over the properties between 2002 and 2004 to better assess the potential of the Projects area to host unconformity-style uranium mineralization. Follow-up ground geophysics including Moving Loop time-domain electromagnetic ("TDEM") and DC resistivity surveys were carried out over prospective airborne conductive zones.
Several areas identified by ground geophysics were noted for testing by diamond drilling. Since then, drilling has been carried out on the Alexandra, Erica, Laurie and Mirror River Projects. On the Alexandra Project, three diamond drill holes and one directional hole were completed in 2001 and 2005. None of the holes intersected a conductor or anomalous radioactivity.
On the Erica Project, seven diamond drill holes and two directional holes were completed between 1998 and 2005. Hole ERC-3 intersected graphitic aluminous gneiss and favourable alteration. A basement structure in hole ERC-3 contained two major fault zones. Graphite was concentrated along these faults, as well as anomalous uranium (up to 442 ppm uranium partial).
Eleven holes were drilled on the Laurie Project between 2003 and 2006 to test the Laurie Conductor. Eight holes intersected the conductor but no mineralization was noted in the holes.
Mirror River Project
A diamond drilling program consisting of five holes was carried out on the Mirror River Project in 2007 to test TDEM conductors defined by geophysical surveys. Two holes intersected sulphide- and graphite-bearing units but little evidence of faulting was observed and radiometric values are at background levels.
A ground geophysical program was completed in 2010 and consisted of 52.5 line-kilometres of Dipole-Pole-Dipole resistivity over conductive areas outlined by previous airborne MEGATEM(r) and ground Moving Loop TEM surveys. Resistivity data was acquired over seven lines of 7.5-kilometre length at 800-metre spacing from line 50+00E to 98+00E.
The 2D resistivity inversion models of the Dipole-Pole-Dipole data characterize the apparent resistivity of the subsurface to approximately 550 metres depth. The results of the 2010 DC resistivity survey correlate well with historical airborne and ground EM data. The 2D resistivity inversion models of lines 50+00E, 58+00E and 66+00E show well-defined low resistivity features at basement depths that could be associated with graphitic conductors. Generally, the outlined low resistivity signatures at basement depths are not linked with noticeable resistivity signatures in the sandstone that could be associated with alteration halos.