The project
This project is focused on developing underground resources beneath the planned final Gokona and Nyabigena open pits. The objective: to bring high grade resources into production in order to provide increased flexibility to mining operations as well as extending the life of mine at North Mara.
The opportunity
In December 2010 we announced an initial high-grade underground indicated resource of 370,000 ounces of gold at 8.29 g/t beneath the planned final Gokona and Nyabigena open pits.
This points to the potential for a substantial underground operation at the Gokona and Nyabigena deposits with an attractive grade profile.
In addition:
- We have carried out a deep diamond-drill programme in and around the current Gokona underground resource area, aiming to extend and validate higher-grade mineralised zones.
- Assay results from the deep drilling gave a better delineation of the extent of several higher grade shoots. They also indicated the potential for further depth extensions of the Gokona system, which remains open at depth to at least 600m etres below the current planned final open pit.
- These positive results have led to a significant resource drill-out programme due for completion in H1 2012. The goal is to expand the total underground resource to greater than one million ounces. We will also use the programme to validate the viability of the underground project.
Our underground feasibility study was successfully completed during Q4 2011 and was based on the 2010 year-end resource. At the same time, during the latter part of 2011, we were able to progress land acquisitions around the Gokona pit and remove a western side road constraint. This provides the potential to increase the open pit reserve ounces by approximately 300Koz through an additional lateral cut back of the open pit, subject to waste dumping constraints and permitting.
The potential lateral expansion of the Gokona pit, if implemented would provide additional near-term production in excess of that anticipated from the underground project. Should the extended Gokona open pit cut back prove the more favourable option, it will mean that the underground project feasibility will need to be re-calculated so as to provide for a revised portal position, results from the successful 2011/12 drilling programme, mining design and infrastructure requirements. While this will lead to some delay in accessing underground production, with the evaluation likely to be concluded by Q4 2012 we remain confident that the project will continue to be viable and our production profile would be enhanced by both the additional open pit ounces as well as the underground project.
Forward activity
In order to build on this progress and further assess the underground potential we anticipate continuing the deep diamond drill programme throughout 2012. The extent of the additional drilling will be determined by mid-2012 after the current phase of drilling is complete and all results have been received and assessed.
Gokona Underground Testing - plan showing current hole locations and the Gokona mid-year 2011 stage 3 pit design (beige and the Gokona year-end 2011 stage 3 expanded open pit design (grey)
Gokona Underground Testing - Section 12825mE showing mineralisation envelopes (red outline), trace of infill drill holes and selected recent high grade results from hole GKD316A