Ashburton Joint Venture
- Major uranium targets highlighted by coincident radiometric and electromagnetic anomalies
The Ashburton Joint Venture project comprises eight granted tenements, prospective for unconformity-style uranium mineralisation in the area south of Paraburdoo in Western Australia.
The Ashburton Joint Venture includes four tenements originally held by U3O8 and four tenements held by Cameco Australia Pty Ltd, the Australian subsidiary of the Canadian based Cameco Corporation, the largest uranium producer in the world. The tenements, covering approximately 1200km2 included in the Joint Venture are included below:
Tenement holding for U3O8 Limited - Cameco Joint Venture
Both parties will have a 50% interest in the Joint Venture as of the commencement date, being 26th September 2007.
From that date U3O8 Limited manage the Joint Venture. If there is a discovery of a mineral resource (defined according to the JORC reporting standards) containing at least 25 million pounds of U3O8, the area of the resource, plus other ground necessary for the development may become subject to a separate Joint Venture on the same terms as in the Joint Venture Agreement, except that Cameco shall have the right to be appointed the Manager of the Development Joint Venture.
In that scenario, U3O8 will remain manager of all other areas of the Joint Venture.
The principal target is the unconformity between Middle Proterozoic Bresnahan Group basal conglomerates (Cherrybooka Formation) and underlying black shales and dolomites of the Lower Proterozoic Wyloo Group. This contact is the focus for known mineralisation at the Angelo River A & B deposits located just to the north. The area is recognised as having strong geological similarities to the Alligator River (host to the world class Ranger and Jabiluka deposits).
The Ashburton Joint Venture includes four tenements originally held by U3O8 and four tenements held by Cameco Australia Pty Ltd, the Australian subsidiary of the Canadian based Cameco Corporation, the largest uranium producer in the world. The tenements, covering approximately 1200km2 included in the Joint Venture are included below:
Tenement holding for U3O8 Limited - Cameco Joint Venture
Both parties will have a 50% interest in the Joint Venture as of the commencement date, being 26th September 2007.
From that date U3O8 Limited manage the Joint Venture. If there is a discovery of a mineral resource (defined according to the JORC reporting standards) containing at least 25 million pounds of U3O8, the area of the resource, plus other ground necessary for the development may become subject to a separate Joint Venture on the same terms as in the Joint Venture Agreement, except that Cameco shall have the right to be appointed the Manager of the Development Joint Venture.
In that scenario, U3O8 will remain manager of all other areas of the Joint Venture.
The principal target is the unconformity between Middle Proterozoic Bresnahan Group basal conglomerates (Cherrybooka Formation) and underlying black shales and dolomites of the Lower Proterozoic Wyloo Group. This contact is the focus for known mineralisation at the Angelo River A & B deposits located just to the north. The area is recognised as having strong geological similarities to the Alligator River (host to the world class Ranger and Jabiluka deposits).
Exploration by previous explorers in the mid 1980s led to the discovery and delineation of the Angelo River uranium deposits. Regional reconaissance highlighted numerous other radiometric anomalies around the unconformity. Four prospects, namely Atlantis, Nobby's, Canyon Creek and Xanadu lie within the project area. At the Atlantis prospect, costean sampling returned exceptionally high grade surface samples (to 37% U3O8). At the Nobby's prospect, drillholes beneath the enriched mineralisation intersected 5.5 metres @ 0.62% eU3O8, and 2.2 metres @ 0.74% eU3O8. At the nearby Canyon Creek prospect, two anomalous zones were defined by radon surveys with rock chip samples returning up to 1% U3O8, whilst at the Xanadu prospect to the west of Atlantis, rock samples returned up to 0.26% U3O8.
A detailed magnetic and radiometric survey was completed over the project area during 2007. An example of some of the data is included below.
The survey covering E52/1893, Canyon Creek not only confirms the tenor of the Canyon Creek radiometric anomaly but also highlights the presence of a large anomaly at the northwest end of the tenement. This large anomaly appear to extend under the Bresnahan Group. The uranium channel radiometrics with the appropriate location of the unconformity is in the figure below.
Radiometrics (uranium channel) on Canyon Creek project
The historical Xanadu anomaly (E52/1879) was the subject of very little follow up work or detailed drilling by the very early explorers, even though there is a pronounced anomaly at the prospect. Of particular interest is a second significant uranium channel radiometric anomaly immediately to the northwest indicating the potential for extensions of the mineralisation under the cover sequence.
The figure below highlights the uranium channel radiometric anomalies on the Xanadu tenement and the inferred location of the target unconformity.
Radiometrics (uranium channel) on Xanadu project
The companies completed a detailed electromagnetic survey over the joint venture area early in 2008. The initial processing of data highlighted several large scale and strike extensive conductors of significant magnitude. The data also shows a subtle conductive horizon at the basement-sandstone contact thereby potentially providing a means of mapping the unconformity under deep cover. Strike extensive conductors are observed to be steeply dipping beneath, and spatially coincident with surface uranium anomalies. Additionally, a coincident conductive-magnetic target located on the Atlantis Project (E52/1880) provides a possible link between the Nobbys and Trend prospects.
Within Canyon Creek (E52/1893) large scale conductors have been identified to be spatially coincident with airborne uranium anomalies, some of which are newly discovered targets. The relationship between surface uranium mineralisation and buried conductors is very encouraging, although not always present.
As an example, a single line of data from the Tempest survey is presented in the first figure below showing a coloured vertical conductivity cross-section down to 250-350m below surface with a profile of uranium, as measured from the air, plotted directly above it. The profile was generated using detailed airborne radiometric data acquired in 2007. The correlation between airborne anomaly and buried conductor is striking.
The coloured section shows a computer generated vertical section of how conductivity varies in the earth down to a nominal depth with blue being the least conductive grading up to red the most conductive.
Vertical conductivity section (blue = weak, red = strong) across a new airborne uranium anomaly within E52/1893. The correlation of buried conductor and surficial uranium responses is significant.
The figure below shows an airborne perspective of how the surface uranium responses correlate with the deeper conductors. All perspective figures have enhanced vertical exaggeration to highlight variation in topography.
An airborne view of the anomaly presented in the above figure showing the location of airborne uranium anomalies (coloured 3D peaks) and the deeper conductor (red markings) when projected to surface.
The aerial prospective immediately below shows the location of conductivity section and the associated airborne uranium anomaly (3D coloured peaks). The red markings along the surface represent the actual location of the deeper conductor.
An aerial 3D perspective of information presented in the figure on the previous page. The coloured conductivity section is correctly located relative to the airborne uranium anomalies.
South of the above anomaly, but still within E52/1893 is the historic Canyon Creek prospect. The Canyon Creek area is located at the south-eastern end of the Ashburton Trough.
The Wyloo metasediments that form the basement in this area appear to be very similar to the ones observed at the Angelo deposits, immediately to the north. Some minor brecciation has been identified and appears to be infilled by some quartz containing secondary uranium minerals. Hematitic cherts and chert breccias apparently interbedded with the Kunderong Sandstone (cover sequence) are lithologically similar to the Angelo A zone.
Additional large scale conductors were detected in the Tempest survey around this region. A single low order uranium response is coincident with the projected surface expression of one of these conductors as shown in the figure below.
An airborne perspective of large scale conductors (red markings) around the historic Canyon Creek Prospect shown with relevant airborne uranium anomalies. The distance between Canyon Creek and the newly discovered anomaly is approximately 6kms.
Further significant electromagnetic and coincident radiometric-electromagnetic anomalies occur on other tenements within the project area.
A detailed magnetic and radiometric survey was completed over the project area during 2007. An example of some of the data is included below.
The survey covering E52/1893, Canyon Creek not only confirms the tenor of the Canyon Creek radiometric anomaly but also highlights the presence of a large anomaly at the northwest end of the tenement. This large anomaly appear to extend under the Bresnahan Group. The uranium channel radiometrics with the appropriate location of the unconformity is in the figure below.
Radiometrics (uranium channel) on Canyon Creek project
The historical Xanadu anomaly (E52/1879) was the subject of very little follow up work or detailed drilling by the very early explorers, even though there is a pronounced anomaly at the prospect. Of particular interest is a second significant uranium channel radiometric anomaly immediately to the northwest indicating the potential for extensions of the mineralisation under the cover sequence.
The figure below highlights the uranium channel radiometric anomalies on the Xanadu tenement and the inferred location of the target unconformity.
Radiometrics (uranium channel) on Xanadu project
The companies completed a detailed electromagnetic survey over the joint venture area early in 2008. The initial processing of data highlighted several large scale and strike extensive conductors of significant magnitude. The data also shows a subtle conductive horizon at the basement-sandstone contact thereby potentially providing a means of mapping the unconformity under deep cover. Strike extensive conductors are observed to be steeply dipping beneath, and spatially coincident with surface uranium anomalies. Additionally, a coincident conductive-magnetic target located on the Atlantis Project (E52/1880) provides a possible link between the Nobbys and Trend prospects.
Within Canyon Creek (E52/1893) large scale conductors have been identified to be spatially coincident with airborne uranium anomalies, some of which are newly discovered targets. The relationship between surface uranium mineralisation and buried conductors is very encouraging, although not always present.
As an example, a single line of data from the Tempest survey is presented in the first figure below showing a coloured vertical conductivity cross-section down to 250-350m below surface with a profile of uranium, as measured from the air, plotted directly above it. The profile was generated using detailed airborne radiometric data acquired in 2007. The correlation between airborne anomaly and buried conductor is striking.
The coloured section shows a computer generated vertical section of how conductivity varies in the earth down to a nominal depth with blue being the least conductive grading up to red the most conductive.
Vertical conductivity section (blue = weak, red = strong) across a new airborne uranium anomaly within E52/1893. The correlation of buried conductor and surficial uranium responses is significant.
The figure below shows an airborne perspective of how the surface uranium responses correlate with the deeper conductors. All perspective figures have enhanced vertical exaggeration to highlight variation in topography.
An airborne view of the anomaly presented in the above figure showing the location of airborne uranium anomalies (coloured 3D peaks) and the deeper conductor (red markings) when projected to surface.
The aerial prospective immediately below shows the location of conductivity section and the associated airborne uranium anomaly (3D coloured peaks). The red markings along the surface represent the actual location of the deeper conductor.
An aerial 3D perspective of information presented in the figure on the previous page. The coloured conductivity section is correctly located relative to the airborne uranium anomalies.
South of the above anomaly, but still within E52/1893 is the historic Canyon Creek prospect. The Canyon Creek area is located at the south-eastern end of the Ashburton Trough.
The Wyloo metasediments that form the basement in this area appear to be very similar to the ones observed at the Angelo deposits, immediately to the north. Some minor brecciation has been identified and appears to be infilled by some quartz containing secondary uranium minerals. Hematitic cherts and chert breccias apparently interbedded with the Kunderong Sandstone (cover sequence) are lithologically similar to the Angelo A zone.
Additional large scale conductors were detected in the Tempest survey around this region. A single low order uranium response is coincident with the projected surface expression of one of these conductors as shown in the figure below.
An airborne perspective of large scale conductors (red markings) around the historic Canyon Creek Prospect shown with relevant airborne uranium anomalies. The distance between Canyon Creek and the newly discovered anomaly is approximately 6kms.
Further significant electromagnetic and coincident radiometric-electromagnetic anomalies occur on other tenements within the project area.