Omitiomire

IBML’s premier asset is the Omitiomire Project, located 120 km northeast of Windhoek in central Namibia. The Project consists of granted EPL 3589, which covers an area of 988 km2. The project area contains the Omitiomire copper deposit and other copper prospects.

Geological Setting

The dominant geological feature of the Omitiomire project area (EPL 3589) is the Ekuja Dome, a Mesoproterozoic basement inlier consisting of felsic and mafic gneisses, partially rimmed by serpentinite and intruded by a number of mafic or ultramafic plugs. The Ekuja Dome contains the Omitiomire copper deposit and other copper prospects. Two smaller domes lie southwest of the Ekuja Dome.

Simplified geological map of EPL3589

Geology of the Omitiomire Deposit

The Omitiomire deposit consists of a system of parallel ore lenses, extending over 3000m in strike, dipping at a shallow to moderate angle to the east, and plunging shallowly to the north-northeast. The lenses vary in thickness. In the northeast, they are typically around 15 – 20m thick but can be up to 50m thick. The superposition of three lenses produces a mineralised zone which may be 100m or more in thickness. In most places, the lenses are separated by barren felsic gneiss but, in some places, the lenses merge.

The following drill sections show the emerging structural model. There is 400m between each of the sections. Note that these are simplified representations, as the copper lenses grade into one another to some extent. Drilling to date has shown that the A Lens and B Lens terminate down dip; the C Lens remains open. Apart from the three main lenses, there are several smaller lenses.

The northern extent of the deposit has not yet been determined. Longitudinal sections show that the ore lenses generally increase in thickness and grade to the north. At the current stage of drilling, the A Lens appears to have terminated but the B and C Lenses remain open-ended down plunge to the north-northeast.

Longitudinal Section 3300E

Primary copper mineralisation occurs mainly as the mineral chalcocite (Cu2S) with minor bornite (Cu5FeS4) within bands of mafic (amphibole-biotite-plagioclase) schist. The highest copper grades are associated with bands of strongly-deformed epidote-biotite schist. Interbanded felsic (quartz-plagioclase) gneiss is barren. Banding is on a scale of centimetres to metres in thickness.

Sawn drill core showing the banded nature of Omitiomire ore.
The brown-coloured mineral is Cr-epidote

The deposit is oxidised to 20m depth and partly oxidised to 40m depth. Additional zones of deeper oxidation extend down near-vertical faults and fractures. The main oxide mineral is malachite, with associated minor chrysocolla and traces of native copper. Oxide material constitutes less than 10% of the resource.

Drilling Strategy and Resource Estimation

The drilling that re-commenced in 2011 had the objective of demonstrating the potential for a resource of at least 1 million tonnes contained copper. Drill holes intersected thick zones of copper mineralisation, including the previously-unknown C Lens in the northeast of the deposit.

The discovery of the C Lens and several infill drill holes completed during 2010 were considered to be sufficient additional data to provide an updated resource estimation. In October 2011, independent consultants Bloy Resource Evaluation provided a new resource model, based on Craton’s geological model. In the northeastern portion of the deposit, the drill hole spacing is too broad (generally 200m x 100m or 200m x 200m) to assign a JORC resource status but Bloy has provided estimates of potential resource.

The resource estimation showed an Indicated + Inferred resource of 123 million tonnes (Mt) at 0.53% Cu (648,000 tonnes copper metal) at a 0.25% Cu cut-off and potential for an additional 600,000 tonnes of copper metal at a 0.25% Cu cut-off. It is likely that a large proportion of the potential resource will, with more closely-spaced drilling, be upgraded to JORC resource status.

Resource estimate by Carrie Nicholls, Senior Resource Geologist,
Bloy Resource Evaluation, October 2011

The resource remains open to the north and northeast. In addition, the newly-discovered C Lens could extend beneath the central part of the deposit. Earlier drill holes will need to be deepened (or re-drilled) to determine the extent of this lens. Drilling has not intersected a deeper D Lens.

Current drilling is aimed at confirming and further extending the potential resource by means of:

Diamond tails on previous RC holes to test for copper within the footwall of the north-eastern part of the deposit;
Additional widely-spaced (approx. 200m x 400m) RC and diamond holes to test the northern and north-eastern extensions;
Drilling shallow targets near to the main Omitiomire deposit.

Preliminary Pit Design

Perth-based Cube Consulting has carried out Whittle shell analysis based on the new resource model and a $3.00 /lb copper price. A pit design and schedule based on Shell 7 (Revenue Factor 0.55) produced 87 Mt at 0.52% Cu at a stripping ratio of 3.6 for a 14.5 year mine life. A pit design and schedule based on Shell 12 (Revenue Factor 0.80) gave 164 Mt at 0.46% Cu at a stripping ratio of 3.9 for a 27.5 year mine life.

Copper Recovery

The banded orebody is extremely amenable to simple beneficiation. Copper is concentrated in dark (mafic) bands whereas pale-coloured (felsic) bands are largely barren. The mafic schist bands are soft (< 150 MPa) and heavy (> 2.8 g/cm3) whereas the barren felsic gneiss bands are hard (> 200 MPa) and light (< 2.7 g/cm3). This difference in physical characteristics between copper-bearing and barren bands permits cheap and effective pre-concentration by dense medium separation (DMS). Testwork carried out at Mintek Labortaories in Johannesburg has shown that this process doubles the grade of mill feed to +1% Cu.

The main copper mineral, chalcocite (Cu2S) contains 79% Cu. Bench-scale studies have shown 90% recovery from the sulphide zone, to produce a high grade (+50% Cu) concentrate with no deleterious elements (As Bi etc). The oxide zone constitutes less than 10% of the total resource; preliminary testwork on this zone indicates around 63% copper recovery.

Proposed process flow chart

Infrastructure Requirements

A pre-feasibility study, completed in 2010, identified the following infrastructure requirements:
• A 90 km water pipeline would connect the project to the Namibian water supply network.
• A 115 km powerline would connect the project to the Namibian power grid.
• Road upgrades would be required to transport copper concentrate either to the existing railway at Nossob siding, or to connect to existing sealed roads to the port at Walvis Bay on the Atlantic coast.
• An on-site village would be built to accommodate the workforce.

Location of Omitiomire in relation to infrastructure

Social and Environmental Impact Assessment (SEIA)

Studies have shown no significant adverse social or environmental impacts. Work in progress includes:
• Routine monitoring of groundwater, dust and the weather station; and
• Specialist field studies on biodiversity/ecology; soils and land capability; air quality; surface water run-off and water balance; hydrogeological modelling; visual impact; noise; traffic; socio-economics; closure costing and public participation.

Discovery Potential

IBML anticipates that ongoing drilling will continue to expand the Omitiomire resource to the northeast.

The Company has carried out extensive soil geochemical surveys within EPL 3589. These show the Ekuja Dome as being regionally anomalous in copper.

EPL 3589: Copper-in-soil

Shallow rotary air blast (RAB) drilling has demonstrated the presence of copper associated with many of the anomalies but there has been little detailed follow-up drilling to date. Collectively, the geochemical anomalies and the RAB drill intersections indicate that the Ekuja Dome is a copper-rich geological entity, with excellent potential for the discovery of additional resources within trucking distance of the Omitiomire deposit.

In addition, there are numerous soil geochemical anomalies outside the dome. Targets have been prioritised for follow-up exploration.