Mayoko Iron Ore Project, Congo
The Mayoko iron ore project is located within the south-west region of the Republic of Congo. The project comprises an extensive tenement covering 1,000km² in West Africa.
The project's owner African Iron owns 80% of the Mayoko exploration licence that was initially held by DMC Mining. The remaining 20% is owned by Equatorial Resources. The exploration licence was acquired by African Iron in August 2010. DMC Mining, which had held 80% of the property since December 2007, began drilling the mine in December 2009.
The Mayoko exploration permit, which was to expire in 2011, has been renewed up to April 2013. The renewed licence has a provision for renewal for two more years.
African Iron plans to commence direct shipping operations (DSO) operations of the Mayoko mine by mid-2013 with an initial start-up level of 5mMtpa.
Mayoko iron ore project geology
The Mayoko iron ore project lies on the Precambrian Congo Craton of West Africa.
The area is characterised by meta-sedimentary rocks, which are more than 2,540 million years old. The rocks are highly metamorphosed almost up to granulite facies.
Iron is hosted within highly weathered iron-rich metamorphic rocks referred to as 'Chapeau de Fer' or hats of iron. Part of the deposit is covered by a high grade hematite-contained ferruginous crust. The crust overlays a weathered and disintegrated ferruginous quartzite zone, consisting of hematite together with low-grade magnetite.
Ferruginous formations in Mayoko also include fresh ferruginous quartzites and colluvia. Colluvia are accumulated material found at the base of the slope, which results from the breaking up of ferruginous quartzites.
Mayoka mine reserves
Reserves in the Mayoka mine are found along a strike length of 1,800m and a vertical extent of 170m. The inferred reserves are estimated at 33Mt graded at 55.6% Fe, 0.096% P, 10.4% Silicon Dioxide (SiO2) and 3.8% Al2O5>. The assumed cut-off grade is 50% Fe, while the average depth of holes is 38m.
Mineralisation occurs in two geological prospects at Mt Lekoumou-Mt Mipoundi and Mt Lekoumou South. The Mt Lekoumou-Mt Mipoundi trend is defined over a strike length of 7km. At this zone, iron mineralisation occurs as open towards the north-east extent of the strike. Along the entire length of the strike, mineralisation takes place as open at depth.
The Mt Lekoumou zone is found along a strike length of 1.5km, which is between 20m-50m deep. Mineral resources in this zone consist of high-grade cap, detrital and high-quality itabirite ores.
Mayoka mine exploration
The exploration of the project zone included trenching and a geophysical survey. Along the Mt Mipoundi zone, 18 trenches for a linear advance of above 690m have been completed. Results revealed evidences of in-situ and detrital iron mineralisation along this zone.
Recent trending and shallow diamond drilling conducted in the past for up to 38 holes also revealed the occurrence of supergene hematite mineralisation graded at 50% to 65% Fe at depths between 10m and 40m from the surface.
A high-resolution airborne geophysical survey was completed in July 2009. Conducted over a 220km² area in the central region of the Mayoko project area, the survey revealed six drill targets covering 0.7t to one billion tons of iron ore.
A similar survey conducted on the remaining 780km² in 2010 increased the exploration target to 1.6-2.6 billion tonnes of ore graded at 30-65% Fe. Around 320-520Mt of target ore graded at 40-65% of Fe corresponds to potential DSO and beneficiable DSO.
A 30,000m oxide resource definition drilling programme was started in February 2011 at Mt Lekoumou and Mt Mipoundi to increase the volume of the existing haematite, DSO, beneficiable DSO and inferred resource.
Results of the first batch drill confirmed the DSO grade of 50-60% Fe and beneficiable DSO at 40-45%.
The updated mineral resource estimates of the drilling programme are expected to be released in December 2011.
Mayoka diamond drilling programme
A diamond drill programme to measure the characteristics of ores found during exploration, including sizes and grades, is currently in progress.
Stage one of the drilling programme, which was completed in April 2010, included 18 drills along the 7km strike of the Mt Lekoumou-Mipoundi zones. The holes were drilled at 1.5km-spaced traverses at depths between 200m and 400m. Stage one confirmed the existing resource and demonstrated banded iron formation (BIF) in lenses 50m to 200m thick over a strike length of 7km.
A hematite and magnetite plant will be required to process the ore. To access the magnetite, a hematite cap will have to be mined first.
The proposed method for processing hematite includes a two-stage crushing circuit that will deliver lump and fines. An 11mt per annum Stage 1B hematite plant is required for the process.
Mayoko mine transport
The Mayoko project is easily accessible with sufficient railways, roads, water supply and ports in close proximity. The project is located within a distance of 2.2km from Pointe Noire rail line, which links to the coast of Pointe Noire.
An agreement was signed between DMC and Chemin de Fer Congo-Ocean (CFCO) in April 2009 to provide rail access from Mayoko to Pointe Noire rail line.
The Port Authority of Pointe Noire (PAPN) signed an agreement with DMC in June 2009 to export iron ore transported from the Mayoko mine site to international markets.