- JORC resource estimates completed at 0.5 g/t Au cut-off: 29.4 mt @ 1.26 g/t Au with contained metal content of 1.193 MOz Au
- Commencement of pit optimisation work on the defined resources to determine most likely mining areas and key sensitivities; potentially focussing on a small "starter" pit of higher grade material
- Mining Lease Application ("MLA") submitted to the Kenyan Department of Mines and Geology for the reprocessing of the Macalder Tailings. Environmental Impact Assessment ("EIA") underway
- Migori Project
Red Rock holds a 15% direct interest in Mid Migori and 85% indirectly through its 42.27% investment in Kansai. Mid Migori is the holder of two special prospecting licences ("SPLs") in Kenya: SPL122 and SPL202. Upon completion of a Bankable Feasibility Study ("BFS"), Red Rock will be entitled to a 60% direct interest.
SPLSs 122 and 202 are located 20–30km north of the operating North Mara gold mine in Tanzania and immediately east of Lake Victoria in SW Kenya.
The licences cover the strike length of the Migori Greenstone belt which hosts felsic and mafic intrusives, banded iron formations ("BIFs") and metasediments. Red Rock focusses on the exploration of gold and base metal mineralisation. The deposit at Macalder is a Volcanogenic Massive Sulphide ("VMS") base metal system of copper and zinc with accessory gold, silver and lead mineralisation. The tailings dump at Macalder is the remnant of colonial era mining of the Macalder deposit.
Mikei Gold Project
Validation of the historic resource estimate was finalised in Q4 2012 with the JORC resource estimation carried out by CSA Global (UK) Ltd. The resource lies over five major zones within the Mikei Shear zone. The first resource to be validated was the KKM prospect at the end of 2011 followed by Nyanza, Gori Maria and KKM-West in July 2012 and MK in December 2012:
29.4 Mt at 1.26 g/t Au with contained metal content of 1.193 MOz Au
|Mikei Gold Project: 2012 JORC indicated and inferred resource estimate (0.5g/t Au cut-off)|
|mt||g/t Au||mt||g/t Au||mt||g/t Au||Metal KOz|
|Gori Maria (GM)||0||0||3.8||1.16||3.8||1.16||141|
NB. Apparent errors may occur due to rounding
Up to 66% of the JORC resources are in the indicated category and a higher cut-off grade of 0.5 g/t Au was chosen to reflect a more realistic estimate to define potentially economic mineralisation prior to determining a cut-off grade for mining as part of planned mining studies.
At a cut-off grade of 0.25 g/t Au, the new JORC resource estimate shows a 30% increase in the tonnage and 16% increase in the contained metal content compared to the historic resource. Mineralisation at all prospects remains potentially open at depth (including down plunge) and along strike of key higher grade zones. This recent work has allowed the interpretation of a high grade gold shoot at the Nyanza Prospect within the Mikei shear zone.
Preliminary pit optimisations are being carried out on areas of shallow, high grade mineralisation in order to determine the potential for economic development and for ongoing resource development (e.g. optimisation of the positioning of drill holes) in all five main prospects. A conceptual pit shell will also be completed for the central high grade pod at Nyanza to explore its potential as a small, high grade "starter" pit.
Nyanza Block Model at 0.5 g/t Au cut-off
Nyanza Block Model at 1.5 g/t Au cut-off (highlighting the high grade zone)
The Macalder deposit was discovered in the mid-1930s and mined for copper and gold. As a by-product of the processing, tailings material was produced and deposited adjacent to the mining area. The tailings contain economic levels of residual gold mineralisation.
In 2011, a JORC measured resource estimate was completed for the tailings dam: 1.3mt at 1.65 g/t Au containing 68 kOz Au. A scoping study was then commissioned in late 2011 to determine the value creation potential of reprocessing the tailings dam for gold extraction. Two base case scenarios were examined (new vs used plant equipment) and a discounted cash flow analysis was carried out. Previous metallurgical test work and the associated community and environmental issues were also assessed in the report with recommendations for ongoing and future work.
3D view of Macalder Tailings Measure resource block model
|Macalder Tailings: 2011 JORC Measured Resource Estimate|
|Prospect||JORC Classification||mt||kOz Au||g/t Au||Cut-off g/t Au|
|Macalder Tailings||Measured||1.3||68||1.65||No Cut-Off|
A Mining Lease Application ("MLA") for processing the tailings was submitted in August 2012 and an EIA is currently underway as part of the full MLA, which involves community consultations to gauge the opinions, concerns and expectations of the proposed project. Advanced metallurgical test work is also in progress, based on the recommendations in the 2011 scoping study report. The main purpose of the test work is to understand any variability in the recovery of gold from the tailings and the effects of copper in the system. Cyanide consumption, leach optimisation time and carbon loading will also be analysed.
The Company is currently researching options for purchasing used plant equipment from the Asian market so planning and construction of the processing plant may commence following the grant of the mining lease.
Migori regional exploration
Following the 8,000 m regional aircore drilling programme in 2011, interpretation work has been ongoing including planning of advanced exploration work over potential high grade targets based on significant aircore results (1.0 g/t Au or more as announced in April 2012).
The next phase of work will involve re-processing of the geophysics data to identify any previously unknown structure that may be controlling mineralisation and assessment of the aircore drilling technique for early stage exploration over other grassroots areas.
Scout drilling was also carried out at regional targets in 2011. The next phase of work is currently being planned to follow up positive/anomalous results (e.g. at Kehancha in SPL202, an intersection of 12.9m at 3.72 g/t Au was drilled) with a view to identifying new, potentially economic targets and expanding the existing resource base.