Kihabe Base Metals Project - Botswana
Location: Ngamiland, Botswana and Tsumkwe, Namibia
Owner: Mount Burgess Mining NL 100%
Project Location
The Kihabe Base Metals Project is located on the border of Botswana and Namibia about 700km north-west of the capital, Gaborone, in Ngamiland. The Project is 350km by road from Maun and 50km from Tsumkwe, Namibia.
Tenements
The Company has tenements covering 100% of the known prospective Proterozoic belt of metasedimentary rocks, with around one third of the prospective geology occurring in Botswana (PL 69/2003, area ~1,000km²) and two thirds in Namibia
The Kihabe Project was held in the early 1980’s by Billiton Botswana (Pty) Limited, which carried out extensive soil geochemical reconnaissance and drilled three anomalous prospects, Kihabe , Nxuu Prospect and the Gossan Prospect.
Regional Geology and Ore Genesis
The prospective geology of the Kihabe Base Metals Project is a belt of Proterozoic sedimentary rocks composed primarily of carbonate and siliclastic rocks. The Belt forms a trapezoidal wedge of tightly to isoclinally folded metamorphosed sediments of the Damaran Supergroup, bounded by granites and gneisses of the Quangwadum Complex and Kihabe Complex.
The target mineralisation is primarily stratiform to stratabound sedimentary exhalative (SEDEX) sulphides occurring at a known stratigraphic level within the basin. The Company’s geological model is that the Belt represents a re-closed rift basin with a fill of arkose, greywacke, quartzites and sabkha-facies stromatolitic dolomites.
The Company has identified that the target contacts between dolomite and quartzite occurs for a combined strike length of 450km within Namibia and Botswana. Incomplete soil geochemical coverage over this stratigraphic interval has identified several zones of anomalism coincident with the contact.
Thirteen soil anomalies for lead, zinc and copper exist within the Company’s tenements in Botswana, which include Kihabe, the Nxuu Prospect, Copper Anomaly and the Gossan Prospect. Extensive reconnaissance soil sampling is underway in Namibia over similar terrain, with several anomalies identified to date.
The Kihabe Zinc-Lead-Silver Resource
The Kihabe Resource is located along a contact between the dolomite footwall and a sequence of rhythmically bedded sandstones, which have been folded and metamorphosed to, respectively, dolomitic marble and chloritic quartzite. The local geology of the deposit is known to be a west-plunging syncline.
Mineralisation is developed within the host quartzite within thick, coarse grained beds, and weakens upwards in the stratigraphy as the grain size reduces. Mineralisation forms a series of overlapping stacked horizons controlled by the beds within the quartzite.
The Company has published an initial JORC Resource at Kihabe within a strike length of 2.4km, an initial program of 13,000m of reverse circulation drilling has defined 11 million tonnes grading 2.55% zinc equivalency. 95% of the Resource reports to an Indicated Category with the remainder within the Inferred Category. Subsequent diamond core drilling has shown a grade increment of 60%, though further drilling is required to verify this.
Diamond core drilling provides better recoveries and sample quality compared to reverse circulation drilling. It will also allow better geological controls to be established with the aim to convert a portion of the existing Resource to the Measured Resource category.
Drill results have confirmed extensions to the resource along strike to the west and the Company is testing a further 8.5km of the Kihabe Syncline within Botswana. There is also a strong possibility of finding extensions to the deposit within neighbouring Namibia.
Gossan Prospect
The Gossan anomaly is a two kilometre long, half kilometre wide soil anomaly with +1,000ppm zinc and +500ppm lead in soil, hosted within a valley bounded by dolomite.
The company has identified an in-situ gossan outcrop with peak values in rock sampling of 21.95% zinc, 7% Pb and 30 ounces per tonne of silver, which is a likely source for the extensive soil anomalism.
Drilling of the Gossan, extending soil and geophysical coverage of the prospective structure, and assessing the potential for hosting a primary zinc-lead sulphide resource is planned.
Nxuu Prospect
The Nxuu Prospect is located approximately 5.5km east south-east of Kihabe. The prospect is defined by a pronounced vegetation anomaly with supporting soil anomalism.Previous reverse circulation drilling returned an intercept of 38m @ 1.6% Zn + 1.2% Pb.
The geology of Nxuu is identified as a syncline of mineralised quartzite similar to the Kihabe Syncline, and thus highly prospective for finding additional mineralisation of a style and tenor similar to that of Kihabe.
The prospect will be to drill during 2008 for the purpose of generating further resources.
Development Progress
Initial desktop scoping studies by ProMet Engineers, based on a hypothetical resource of 17.5Mt at an assumed grade of 3% zinc and 1% lead, showed that if such a deposit could be found in the Kihabe Project, it could be profitably extracted via bulk open cast mining at long term metals prices.
Subsequent work by the Company has involved proving additional resources and improving the grade of the Kihabe resource area to improve upon the current 11Mt at 2.55% zinc equivalency. Initial scout metallurgical programmes showed that recoveries in the range of 90-94% were possible from the Kihabe mineralisation. Key scoping study assumptions have been reviewed and further work is planned.
The Company’s intention is to progress the Kihabe Resource to a definitive feasibility study and decision to mine via;
- Proving additional resources via aggressive extensional drilling to meet or exceed the resource parameters provided by the ProMet scoping study
- Improving grade continuity and overall resource grade with diamond core drilling
- Progressing and advancing metallurgical and ore characterisation studies
- Improving and updating key feasibility study assumptions and economic modelling
- Defining additional resources within the belt for inclusion in mining schedules
