18th Dec 2007 07:01
African Minerals Ltd18 December 2007 African Minerals Limited ("African Minerals" or "the Company") Tonkolili Iron Ore Exploration Update African Minerals Limited (AIM:AMI), a company focused on minerals exploration inSierra Leone, West Africa, is pleased to announce the following update onprogress at its flagship Tonkolili iron ore project. Since the last technicalupdate on the Company's iron ore assets provided on 24 July 2007, the Companyhas: • Continued its exploration programme, comprising diamond coring and reverse circulation drilling, completing 11 deep diamond holes and 12 short reverse circulation percussion drill holes; • Received complete analytical results for three diamond drill holes; • Confirmed the exploration potential for a large scale magnetite iron ore deposit at Tonkolili; • Conducted preliminary metallurgical testing on three diamond drill holes confirming the mineralisation can be upgraded to a magnetite fines concentrate product in excess of 68% Fe; • Executed contracts for a major expansion of the drilling programme for early 2008; • Commenced a preliminary scoping study on rehabilitating the disused Pepel port, ship loading and rail infrastructure; and • Created a dedicated iron ore division headed by a new President, Iron Ore and Base Metals. Commenting on the Tonkolili exploration update, Frank Timis, Executive Chairmanof African Minerals said: "I am very pleased by our progress at the Tonkolili iron ore project in recentmonths and with the additional drill rigs we will be in a good position toaccelerate our drilling programme in 2008. Bruce Kirk, our President of Iron Oreand Base Metals, is currently based in Sierra Leone to provide hands-on projectmanagement and planning experience in readiness for the expanded drillingprogramme. Our work in recent months demonstrates real progress by AfricanMinerals towards achieving our strategic goal of creating a substantial iron orebusiness in West Africa." New Drilling Contracts The Company has entered into drilling contracts with Boart Longyear Canada forthe supply and operation of four drilling rigs which will have the capacity todrill holes in excess of 400m long, and with Mindrill Pty Limited of SouthAfrica to provide and operate five multi-purpose rigs. The Company expects tohave all nine rigs in Sierra Leone during the first quarter of 2008 and willtherefore be able to commit to a major drill programme with the intention ofdefining the resource parameters during 2008. A large modern camp and associated infrastructure is under construction atTonkolili with anticipated completion in early 2008 to support the expandeddrilling programme. Exploration Target The Tonkolili Project is located within EXPL 005/06, a licence held by TonkoliliIron Ore (SL) Limited, a wholly owned subsidiary of African Minerals, in theSula Mountains Greenstone Belt of Sierra Leone. The exploration target at Tonkolili is a large tonnage magnetite resource hostedin a magnetite bearing iron formation ("BIF"). This style of mineralisation can be upgraded by simple magnetic separation witha high mass recovery of magnetite (over 30%) to produce a magnetite iron orefines product with high iron content (up to 70% Fe) and low silica and aluminacontaminants (less than 4%). This metallurgical process is a proven conventionaltechnology in common use globally for several years. The resulting high grademagnetite concentrate is suitable for producing high quality iron ore pellets. The current iron ore exploration programme is focussed on the Numbara andSimbili prospects at the southern end of a prominent 28 kilometre long,northeast-southwest trending aeromagnetic anomaly mainly due to a magnetitebanded iron formation (Figure 1). While there is a reasonable correlationbetween the magnetic anomaly and magnetite in BIF, magnetic zones in rocksunrelated to BIF are also present e.g. Drill Hole NUDD 018 (Figures 5 and 6). The BIF at Numbara is overlain by a lateritic profile varying from approximately40 to 80 metres in vertical thickness where tested by drilling (Figures 3 and5). In the laterite zone, the original magnetite is replaced by goethite andhematite. Due to its medium iron grades and high silica and alumina content thislateritic material is not of direct shipping grade or quality. However, limitedmetallurgical testing is ongoing to determine whether a beneficiated iron orefines product can be produced from this particular laterite zone. The primary geology consists of a central zone of BIF inter-bedded with lowergrade sediments e.g. Drill Holes NUDD04 (Figures 5 and 6) and NUDD023 (Figure3). The drilling conducted at Numbara to date is not adequate to establish thecontinuity of iron grades in the BIF. The current drilling programme is designedto determine grade, continuity and size potential. Recent structural analysis of the limited diamond drilling conducted to dateindicates that target BIF zone at Numbara apparently has a dominant steep dip tothe northwest. This suggests that Drill Holes NUDD 003 and NUDD021 were drilledat a low angle to the bedding and consequently the true width of theintersections in these drill holes will be narrower than the original apparentwidth. Further drilling with a south east orientation is in progress todetermine the dimensions and grade of the magnetite bearing BIF zone. No drilling has been conducted on the Simbili project to date with the firstdrill holes to test the area anticipated in early 2008. Drill hole planning forSimbili is in progress and drill site access is under construction. Infrastructure The Tonkolili project is located approximately 150 kilometres from the port ofPepel, the site of a disused existing iron ore port with stockpiling and shiploading infrastructure last operated in the 1970's and owned by the Sierra Leonegovernment. A disused railway line extends from Pepel to the former iron ore mine atMarampa, located approximately 100 kilometres from Tonkolili. A preliminary study by external consultants retained by African Minerals is inprogress. The scope of work is to assess the condition of the port and railinfrastructure, its capacity and rehabilitation requirements and also to studythe potential extension of the Marampa rail line to Tonkolili. Drilling Diamond drilling was conducted using the Company's light rigs. Eleven diamonddrill holes have been completed on the Numbara prospect to date with a furthertwo diamond drill holes in progress for a total length of 2,461 metres completed(Table 1 and Figure 2). While these light rigs are well suited to thereconnaissance phase, heavier duty diamond core and reverse circulation ("RC")drill rigs are required for the proposed major drilling programme scheduled tobegin in early 2008. During July and August 2007, a Company tractor-mounted RC rig drilled a seriesof 12 short vertical RC percussion holes at Numbara (Table 3 and Figure 2). Theaverage drill hole depth was relatively short at 63 metres as the lightequipment was only able to penetrate a short distance into the unweathered rockat the base of the laterite. Seven of the twelve holes intersected magnetic BIFat the base of the hole, but as only very short intersections were achieved,these are insufficient to establish continuity of magnetite BIF at depth. Drilling Results The current high level of global demand for analytical and metallurgicallaboratory services in the minerals industry has delayed the chemical analysisand metallurgical test work on the drill hole samples. Consequently, the assayresults for only three diamond core holes NUDD 003, 004 and 005 are reported(Tables 1 and 2). Relocation of the African Minerals sample preparation laboratory to Tonkolili isplanned for early 2008 to handle the increased sample preparation requirements.A substantial expansion of its capacity is under consideration. Chemicalanalysis of drill core and RC drill samples was conducted by SGS Australia PtyLtd, Amdel Limited and Ultra Trace Pty Ltd laboratories in Australia. QualityControl Quality Assurance (QCQA) procedures are employed at the project site andby the laboratories to ensure optimal data accuracy and precision. Metallurgical Test Work Samples from three diamond drill holes, NUDD003, 004 and 005 were subject topreliminary metallurgical assessment of magnetite recovery by the Amdel LimitedMineral Laboratories division, a reputable Australian laboratory. The preliminary testwork demonstrated that the BIF at Numbara can be processedby conventional magnetic separation to produce a magnetite concentrate with highiron (67% - 69% Fe), low silica (3.7% to 5.9% SiO2) and low alumina (0.2% to0.6% Al2O3). The weight recovery of the concentrate from the BIF intervals inthese three drill holes ranged from 29.2% to 33.9% (Table 2). Amdel Mineral Processing WA also conducted a preliminary metallurgicalassessment of NQ drill core from drill hole NUDD003 from the Numbara prospect.The aim of the testwork was to determine the chemical and physicalcharacteristics of the magnetite BIF in 2 metre sample intervals. Fourlithologically distinct zones were defined, identified and characterised as "duricrust" (0-12m), "saprolite" (12-34m), "weathered BIF" and "primary BIF"(43-303m). Size fraction assay testwork on the "duricrust" and "saprolite" zone intervalcomposites showed no potential for beneficiation by selective removal of Al2O3. Physical characterisation data from selected intervals of the two BIF zones inDrill Hole NUDD003 are summarised in Table 4. Other Exploration Activities The Company is also actively developing its base metal exploration projects andwill provide updates on these projects as results become available. The Companyis continuing its bulk sampling programme at the Konama alluvial diamondproject. Diamonds produced during this programme will continue to be soldthrough an industry recognised diamond marketing company to maximise value. Please note that the Figures referred to in this Exploration results report toprovide geological context and relative location of drill holes and analyticalresults can be found by clicking on the following hyperlink: http://www.african-minerals.com/Doc/pdf/Research/TonkoliliUpdate.pdf ENQUIRIES: African Minerals Limited Tel: +44 (0) 20 7849 3002Frank Timis (Executive Chairman)Roy Pitchford (Chief Executive Officer) Canaccord Adams Limited Tel: +44 (0) 20 7050 6500Mark AshurstMike Jones Citigate Dewe Rogerson Tel: +44 (0) 20 7638 9571Media enquiries: Martin Jackson/ Kate DelahuntyAnalyst enquiries: Scott Fulton NOTES Some statements in this news release are forward looking and consequentlyinvolve uncertainties and risks that could cause actual results to differmaterially from those anticipated from initial indications. Such forwardlooking statements include comments regarding exploration work. The Companydisclaims any obligation to update forward looking statements. The information in this report relating to iron ore exploration results is basedon information reviewed and compiled by Bruce Kirk, who is a Fellow of theAustralasian Institute of Mining and Metallurgy. Mr. Kirk, President Iron Oreand Base Metals, is a full-time employee of the Company and meets therequirements of a "Qualified Person" under the AIM Guidance Note on Mining, Oiland Gas dated March 2006 for iron ore Exploration Results. Mr. Kirk hasconsented to the inclusion of this information in the form and context in whichit appears in this report. It should be noted that there has been insufficient exploration to define aMineral Resource and it is uncertain if further exploration will result in thedetermination of a Mineral Resource. The grades of the drill holes presentlyreported may not necessarily reflect the ultimate grade of the potential target. APPENDICES TABLE 1 Diamond Drill Holes Numbara Prospect Hole Number Hole Length Sampling Analyses Remarks NUDD001 39.5 complete complete terminated earlyNUDD002 38.5 complete complete terminated earlyNUDD003 303.4 complete complete -NUDD004 249.5 complete complete -NUDD005 255.5 complete complete -NUDD013 250.5 complete partial -NUDD018 179.5 complete partial -NUDD019 231.5 complete pending -NUDD020 114.5 complete pending terminated earlyNUDD021 239.5 complete pending -NUDD022 248.0 complete pending -NUDD023 228.5 pending pending in progressNUDD024 83.0 pending pending in progress13 Holes 2461.4m TABLE 2 Diamond Drill Hole Assay Results Primary BIF Analyses Numbara ProspectHole Number From (m) To (m) Length Fe% SiO2% Al2O3 % P% DTMR % DT Fe% DT DT Al2O3 DT P% (m) SiO2 % % NUDD001 - - - - - - - - - - - - NUDD002 - - - - - - - - - - - - NUDD003 34.0 303.4 269.4 35.2 41.2 3.10 0.042 33.9 69.0 3.73 0.23 0.008 NUDD004 118.0 156.0 38.0 32.1 42.7 4.35 0.050 29.2 67.0 5.90 0.59 0.011 NUDD005 94.0 255.5 161.5 35.1 41.0 3.18 0.049 32.8 68.7 4.19 0.24 0.001 Note: • Drill holes NUDD001 and 002 were terminated early and did not intersect the target BIF zone. • Some drill holes, notably NUMDD003 and 21 drilling northwest, intersect the interpreted NW dipping BIF sequence at a low angle and are not true widths. • Analytical results are awaited for all drill holes after NUDD005. • DTMR is the % mass recovery of the magnetite concentrate produced by the Davis Tube magnetic separation test work • DT% is the chemical composition of the magnetite concentrate produced by Davis Tube magnetic separation test work e.g. DT Fe% is the iron content of the magnetite concentrate TABLE 3 Reverse Circulation Drill Holes Numbara Prospect Hole Number Hole Length Sampling Analyses Rock Type at End of Hole NURC006A 13 complete complete laterite NURC006B 52 complete complete clay NURC007 54 complete complete sediments NURC008 50 complete complete sediments NURC009 77 complete complete BIF NURC010 84 complete complete BIF NURC011 90 complete complete BIF NURC012 71 complete complete BIF & clay NURC014 67 complete complete BIF NURC015 46 complete complete clay NURC016 80 complete complete BIF NURC017 72 complete complete BIF 12 Holes Total 756m TABLE 4 Physical Properties Drill Hole NUDD003 Selected Samples Numbara Prospect Hole Number Sample Depth (m) Lithology Density UCS Average CWi (t/m3) (MPa) (kWhr/t) NUDD003 35-36 weathered BIF 3.33 15.1 2.92NUDD003 50 primary BIF 3.58 16.6 7.03NUDD003 70 primary BIF 3.69 178 9.56NUDD003 90 primary BIF 3.69 73 9.0NUDD003 110 primary BIF 3.69 110 10.2 Note: • UCS - Unconfined Compressive Strength • CWI - Bond Crushing Work Index used to calculate actual crusher power requirements This information is provided by RNS The company news service from the London Stock ExchangeRelated Shares:
AMI.L