Exploration

Billiton explored the Mumbwa licence area during the mid to late 1990's. The following conclusions were derived from the mapping, geophysics, geochemistry and drilling completed.

The Kitumba region contains a large, and in the areas tested so far, low-grade copper or copper-gold bearing, breccia system comparable in size to the Olympic Dam Breccia Complex.

Geological, textural and geophysical data support the presence of intensive leaching and oxidation of the upper portions of the breccia systems, particularly where silicification is weak.

Geophysical and geological data support the presence of a large, potentially supergene enriched zone at the base of the oxidised zone (~250-500m). However, this target and theory has not been adequately tested.

The geological structure of the target area is not well understood and a better understanding of this may assist in focusing further exploration.

A better understanding of the geophysical properties of the rocks in the Kitumba targets is required for the effective placement of further drill holes.

Geology of Kitumba Prospect

A Falcon^TM survey provides the best means of providing a better understanding of the geological structures and the geophysical properties of the Mumbwa licence area.

It has been demonstrated from BHP Billiton's internal interpretation work carried out on Olympic Dam (South Australia) that it may be possible to discriminate the major mineralised systems in an IOCG province using 3D inversion of regional gravity and magnetic data.

The Falcon^TM data complements the existing geological, geophysical and geochemical data. The data was analysed for related vertical gravity gradient ("GDD") and magnetic anomalies that may indicate the presence of IOCG style mineralisation. The targets were ranked based upon the GDD signal amplitude, a real extent, related magnetic signature, as well as anomalous uranium signatures and their location with respect to mineral occurrences and favourable drill results. Interpretation culminated in a total of 23 anomalies being identified by the Falcon^TM survey, of which 11 priority drill targets were sited from for drilling.

In 2006/2007, Phase II of the exploration program completed drilling 8 holes totalling 4105.17m, of which drillhole S36-001 intersected 655m at 0.46% copper. This drill hole terminated in mineralisation at 697.4m, and the drill rig did not have the capacity or drill rods to progress further. The average depth of drillholes from the Phase II drilling program were in excess of 500m depth.

In 2007/2008, Phase III of the exploration program was initiated, proposing to core drill 10,200m from a planned 20  hole program.  Drilling commenced in January 2008, utilising two drilling rigs to follow up on encouraging results identified during the previous Phase II drilling campaign. The proposed drill holes are listed, and provide the proposed hole depths and trend of the drillholes.