The Callawa Copper Project comprises an exploration licence application E45/5842 which is pending at the application stage. It has an area of 52 BL (167 km2). The Callawa Copper Project is located approximately 85km northeast of Marble Bar.
The Callawa Copper Project covers a large area of the Warrawagine Granitoid Complex on the north-north-eastern margin of the Pilbara Craton, a poorly-exposed sequence of mafic and ultramafic xenolith-rich foliated gneissic granitoids. Copper (Cu) mineralisation within quartz veining has been recorded in several locations. Associated elevated gold values indicate a potential porphyry-style origin to the copper/gold occurrence. Outcropping high-grade Cu gossans in the Callawa area appear to be superficially enriched in Cu. The minerals observed in an outcrop are largely malachite. The air core drilling completed by Montezuma Mining Limited during 2008 did not sufficiently test the depth potential of the surface high-grade copper areas.
The Callawa Copper Project is an early-stage exploration prospect for greenstone hosted vein Au (Cu) also. Mineralisation occurs near the margin of ultramafic xenolith within granites of the Warrawagine complex. The mineralisation visible at surface comprises secondary copper dominated by malachite within highly altered quartz mineralised and sheared/brecciated host rock. The degree of alteration observed in the samples is indicative of the potential for this to be a part of a major mineralised system. Although no significant Au values have yet been obtained, the indicator elements assays are strong enough to encourage continued exploration with this refocus on Au or VMS style Copper Prospect.
The historical exploration at the Callawa Copper Project is limited in nature with shallow drilling, however, indications of significant mineralisation warrants follow up exploration. The Callawa Copper Project demonstrates significant potential for a further copper-gold discovery within the Archean Warrawagine Granitoid Complex on the margin of the Pilbara Craton.
The tenements are within the Archean (3660 Ma) Warrawagine Granitoid Complex on the north-north-eastern margin of the Pilbara Craton. This is a poorly described sequence of mafic and ultramafic xenoliths-rich foliated gneissic granitoids. The batholith is only 1/3 exposed, with the remainder covered by recent alluvial and Tertiary sediments to the North.
Most of the previous work was conducted by Montezuma Mining Company Limited during the 2006 – 2010 period.
The review of the geophysical data identified the presence of a geophysical (magnetic) anomaly running north-south through the tenement. This anomaly consisted of 2 parallel weak mag highs. To the north, this anomaly directly underlies known high grade (20+%) copper-rich gossans. There is also coincidental paler soil and outcrops in Google Earth images.
The State Gravity map showed a clear low coinciding with known outcropping granite. However, in areas undercover, the gravity low is still clear and is bounded by stronger gravity greenstone rocks. The Magnetics data also indicates that potentially more rafts of greenstone are in the Warrawagine Granite. There is still uncertainty as to whether this is a very large enclave or a roof-pendant. At this stage of exploration, the raft is considered to be more of an enclave due to the lack of top of granite features such as pegmatites or differentiation.
Montezuma collected 18 rock chip samples in 2008 from outcropping gossanous material and outcropping quartz-bearing rocks (Figure 1).
Some significant Cu values including 9.35% Cu, 7.63% Cu and 2.6% Cu were obtained in rock chip samples in fairly plain looking, massive quartz. Details of the rock chip sample locations and significant results (>0.1% Cu) are included in Appendix F to the Independent Geologist’s Report.
An air-core drilling programme was completed in 2008 comprising of 17 holes for 564m. Drilling was done on 2-line formation, 5km apart, south of the De Grey River, centred over the geophysical anomaly, seeking extensions under cover of the mineralisation seen at the outcropping Cu occurrences (Figure 1).
The drilling failed to confirm the high-grade surface results, however, did return significant Pb anomalism and weak Zn anomalism at depth within amphibolites. Overall, a broad zone of low order base metal anomalism was identified, open to the north. Additionally, significant geological complexity was identified, including amphibolite, and meta-sediments in addition to the regional granitoid.
Drilling completed by Montezuma Mining Limited in 2008 did not sufficiently test the depth potential of the surface high-grade copper areas–the Air Core drilling program failed to intersect the target zone, was unable to penetrate below the cover and many holes had to be abandoned. An RC drilling program was recommended at the time but never followed up. The drilling data suggests a mesothermal amphibolite hosted quartz system, possibly derived from a VMS source within the greenstone package. Although the Au values are low relative to the higher base metal values, the south to north increase in max Pb and Zn leaves the anomalism open to the north. This area correlates to both a Geophysical mag High and apparent folding in the host greenstone raft.
Proposed Exploration Program
The historical exploration at the Callawa Project is limited in nature with shallow drilling, however, indications of significant mineralisation warrants follow up exploration. The Callawa Project demonstrates significant potential for a further copper-gold discovery within the Archean Warrawagine Granitoid Complex on the margin of the Pilbara Craton. The proposed exploration program of the Company will involve initial mapping followed by geophysical surveys to test the mineralisation potential along strike followed by drilling to test deeper Cu prospect.