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Dajarra Project |
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Many of the elements of Superior's copper exploration model exist in this project area.
The favourable features of this project area include:
The July 2007 VTEM survey shows the Elizabeth and RFZ prospects as high-priority EM anomalies: The Elizabeth Anomaly lies within an area of Mount Isa Group sediment equivalents south of the junction of Rufus Creek and Sulieman Creek. The RFZ Anomaly lies within an area of Mount Isa Group sediment equivalents located on the southern extension of the Rufus Fault Zone. Elizabeth Prospect The Elizabeth EM Anomaly, which lies within EPM15040, is considered a very high-priority target area. It was originally outlined on five consecutive flight lines spaced at 500m intervals in the July 2007 VTEM survey. Geotech Airborne Pty Ltd completed more detailed VTEM (100m spacing) over the Elizabeth Anomaly in December 2007 to better detail the anomaly and to determine its full extent. The anomaly has a length in excess of 2000m, a width up to about 400m and it lies at a depth in excess of 100m. It does not outcrop. Interpreted conductivities are consistent with a sulphide deposit but these could also reflect graphitic sediments which are also conductive. Most of the area of the Elizabeth Anomaly is covered by red sandy soil derived from weathering of the basal sandstone unit of the Cambrian sedimentary cover. In the northern portion of the anomaly subdued outcrops of strongly ferruginous (iron-rich) Proterozoic siltstones indicate that the host sediments of the anomaly are probably Mount Isa Group sediment equivalents. Scattered outcrops of ferruginous sandstone which belong to the Cambrian cover sequence indicate that iron is enriched on the Cambrian unconformity. It is uncertain at this stage if the iron in the strongly ferruginous Proterozoic siltstones is due to iron enrichment on the unconformity or is derived from original pyrite in the siltstones. Broadly the geological setting of the Elizabeth Anomaly is similar to that at Mount Isa where the Mount Isa Group sediments containing the Mount Isa deposits are faulted against basalts and quartzites along a major north-south fault. Two shallow vertical holes were drilled into the Elizabeth VTEM anomaly in December 2007. These intersected siltstones which were quite deeply weathered and the drilling failed to provide any substantial information on the cause of the anomalies. Drilling of six deeper holes to test the anomaly at greater depth was completed in March and April 2008. The deeper drilling at Elizabeth intersected low-grade copper and lead-zinc mineralization within pyritic and dolomitic siltstones in two holes (EZ005 and EZ006) on the western side of the area. Hole EZ006 also intersected 24m of silicified siltstone containing quartz-dolomite breccia which is similar to the quartz-dolomite breccia (silica-dolomite) which hosts the copper mineralization at Mount Isa. During July 2008 down hole EM surveying of three of the Elizabeth drill holes was completed (Holes EZ004, EZ005 and EZ007). Unfortunately hole EZ006 was blocked at 50m and could not be surveyed. Computer modelling of the down hole EM results indicates that graphitic siltstones have been at least partly responsible for the VTEM anomaly at Elizabeth. However it has also shown additional conductive bodies that have not been tested by drilling which will be targetted by the next drilling program. A gravity survey was completed over the Elizabeth Prospect in October and November 2008. Sulphide orebodies usually contain appreciable amounts of dense minerals and a gravity survey represents an appropriate method for separating EM anomalies over sulphide orebodies from those anomalies over graphitic rocks. The gravity survey involved the reading of 905 gravity stations at 100m intervals along lines spaced at both 100m and 200m intervals. The survey also covered a circular feature showing on air photographs and satellite imagery in the northern portion of the Elizabeth Prospect. The survey showed a pronounced gravity low over the circular feature in the central northern portion of the area surveyed as well as a gravity low in the south-eastern portion of the area surveyed. These gravity lows indicate that low density material lies beneath these areas. The low density material is unlikely to be sulphide mineralisation as this is normally of high density. Other more subtle gravity high features were detected by the survey. These may reflect sulphide mineralisation. The data from the gravity survey was subjected to computer modelling to produce a 3D density model of the area beneath the area surveyed. This 3D density model shows a pronounced 'carrot shaped' density low beneath the circular feature in the northern portion of the prospect area leading to the probable interpretation of a volcanic diatreme lying beneath this area. This volcanic diatreme, if it exists, may have potential for diamonds. The 3D density model also shows a second density low feature under the gravity low in the south-east corner of the area. this area may also have diamond potential. The 3D density model also shows a density high which is coincident with a conductivity high interpreted from the VTEM survey. This area has potential for sulphide mineralisation. Drilling of the targets outlined by the gravity survey is planned for the 2009 field season. This drilling will test for copper, lead and zinc deposits within the prospective Mount Isa Group sediment equivalents where potential is indicated by the VTEM and gravity surveys. Drilling will also test the diamond potential of the circular feature in the northern portion of the area. RFZ Prospect The RFZ EM Anomaly lies within the eastern portion of the RFZ Prospect. The anomaly exists on six of the flight lines from the July 2007 VTEM survey. The flight lines were spaced at 250m intervals and therefore the anomalous area has a length of 1.5km. The stronger part of the anomaly occurs on two lines. Modelling of the anomaly indicates that the conductive source is an easterly dipping body. The geology of the area consists of Proterozoic siltstones and shales with some surficial ironstone bodies which may reflect pyritic sediments. Soil sampling at a spacing of 200m X 50m has been completed over the RFZ Prospect. This has outlined two low order copper anomalies over fine grained Proterozoic sediments. One of the anomalies corresponds with the RFZ EM Anomaly and one is in the south-western corner of the prospect area. Drilling of four holes into the RFZ EM anomaly was completed in December 2007. Assay results do not indicate significant base metal results. The RFZ prospect remains as a moderate-priority target area. It is a large area of prospective sediments which are interpreted to be equivalent to the Mount Isa Group. Work on the area has been temporarily delayed while exploration is carried out on the higher priority Elizabeth Prospect. Other Prospects At the Carbine Prospect the July 2007 VTEM survey outlined a high-priority conductive anomaly on one flight line. More detailed VTEM surveying at 100m spacing in December 2007 better defined the anomaly. Drilling will be completed on the Carbine Prospect when a suitable drilling rig is available and higher-priority work on other prospects is completed. Drilling of the Rundle Prospect (EM anomaly) has been completed. Assay results do not indicate significant base metal results. Two holes have also been drilled at the Buckingham Prospect. These have intersected magnetic dolerite which adequately explains the magnetic anomalies at this prospect. |