Considering a 50 m deep open pit over the 6 km2 target zone at Wilkinson Hill and a grade of 400 g/m3 there is the potential for a 120,000 tonnes coltan resource with the associated tin, ilmenite, gold, zircon and magnetite accessory minerals
The company mapped out all Coltan mining areas within its license area
Geochemical analysis of soil samples suggested the alluvial Coltan areas are coincident with anomalous soil values for Ta and Nb over the catchments areas of the narrow swamps.
76 test pits were completed in 19 swamps and 117 eluvial test pits in the Katanta prospect to test the potential of alluvial Coltan occurrence.
A total of 2155 samples were collected form Matanta target.
All samples collected were analysed using Niton XRF analyser.
Randon samples were analysed at AH Knight, ALS (Vancouver), AVX Tantalum (Czech Republic), H.C Starks (Germany).
Grades of over 50% Ta2O5 were returned for some samples while higher percentage of the samples fall between 15 – 25% Ta2O5 for all samples.
Analyses show economic values for Sn and Nb in the samples.
Coltan Mineralization Styles
Coltan processing lab was developed with high HSE standards combined with robust QAQC procedure.
Sn (Tin) is used as a pathfinder element to identify areas of Coltan concentrations.
Soil geochemistry over the Khatanta area shows strong Sn anomalies developed on the western flanks of the “Wilkinson Hill”.
The Sn in soil anomaly has a footprint of approx 6.6km².
Coltan found in weathered pegmatites in both alluvial and eluvial settings.
On average 40% of the heavy mineral concentrate in the alluvials is coarse material (>1mm) which comprises coltan and “ilmenite”. The 60% finer material (<1mm) includes coltan, magnetite, ilmenite, cassiterite and garnet.
Coltan has an SG of 8+, is strongly resistant to weathering thus coarser material is expected to remain proximal to the primary source – density and widths of pegmatite veins will be important.
SRK is of the opinion that the most prospective zones for coltan mineralisation will be the upper reaches of rivers and streams and terraces or higher ground above them.
Excavation of 50m long trenches over geochemical anomalies for Ta/Nb and Sn. A total of 13 Pegmatites dykes, the largest of which was 6m wide, with elevated Ta/Nb and Sn values were intersected indicating the occurrence of source rock within the license area
Geochem analysis of composite samples from trench returned grades over 200 ppm with the highest grade >800ppm