2nd Feb 2009 07:00
2 February 2009
For immediate release
African Minerals Limited
("AML" or the "Company")
4.7 BILLION TONNE INITIAL RESOURCE ESTIMATE CONFIRMS TONKOLILI IRON ORE PROJECT AS WORLD CLASS
African Minerals Limited (AIM: AMI), the mineral exploration company with significant interests in Sierra Leone, West Africa is pleased to announce an initial Mineral Resource estimate of 4.7 billion tonnes at an average grade of 29.9% Total Iron for the Numbara and Simbili targets at its flagship iron ore project at Tonkolili, Sierra Leone.
HIGHLIGHTS
4.7 billion tonnes at 29.9% Total Iron
Magnetic concentrate mass recovery of 29.3%
Iron ore grade magnetic concentrate at 67.8% Fe, 4.8% SiO2, 0.5% Al2O3, 0.005% P
2.8 billion tonne Indicated Mineral Resource
1.9 billion tonne Inferred Mineral Resource
Potential to increase resource tonnage and confidence level
SUMMARY
This resource estimate was prepared by independent consultants SRK Consulting (UK) Ltd ("SRK"), and complies with the 2004 edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, (the JORC Code1). The resource estimate is reported based on exploration data current to 12th December 2008.
The Mineral Resource estimate comprises a 2.8 billion tonne Indicated Mineral Resource and a 1.9 billion tonne Inferred Mineral Resource.
Previous metallurgical test work carried out on bulk samples of the primary BIF at Tonkolili indicates that a concentrate assaying 68% Fe or higher is achievable with a silica level in the magnetite concentrate varying between 3% and 5%.
Systematic Davis Tube Recovery ("DTR") test work has been conducted on all samples where the magnetite content is in excess of 8% (as determined through on-site Satmagan testwork). This resulted in a total of 1,996 samples used to define an average concentrate grade of 67.8% Fe, 4.8% SiO2, 0.5% Al2O3, 0.005% P.
All metallurgical test work and assays for this reported resource have been completed by independent mineral processing consultants AMDEL Ltd., Perth, Australia, and their subsidiary Ultra Trace, Perth, Australia.
The hematite rich lateritic cap overlying the primary BIF offers potential to grow the reported resource, and will be reported once a more accurate topographic surface is included in the resource model. The Company has signed a service contract to acquire this data using airborne LiDAR technology. Mobilisation of the survey has already commenced.
The Company is committed to expediting a pre-feasibility study to assess the economic viability of the project, and will continue to provide updates to the market as the information becomes available.
The Company maintains an ongoing and comprehensive metallurgical test program to provide detailed metallurgical input into the pre-feasibility study.
In addition to resource definition, exploration continues at the Marampon prospect, lying at the northern end of Simbili, which offers significant potential to increase the primary BIF hosted magnetite resource.
Reconnaissance drilling is planned for the Kasafoni area which features approximately 20km strike length of magnetic target consistent with mineralised BIF, noted at Numbara and Simbili.
______________________
RESOURCE ESTIMATE
The Company began its exploration drilling programme at Tonkolili in 2007 to investigate strong anomalism noted in aeromagnetic data that extends for approximately 28km over the Sula mountain range of Sierra Leone.
Two principal targets, Numbara and Simbili were identified to the southern end of the magnetic anomaly, and yielded very encouraging iron grades from reconnaissance surface trenching and reconnaissance drilling during 2007. An intensive systematic diamond drilling programme commenced in 2008, with drilling concentrating on the widest portions of the two targets.
Numbara has been explored on a predominant 300m by 100m drill grid and Simbili on a 400m by 200m drill grid. As of 12th December 2008, Numbara has been explored by a total of 94 diamond drill holes for 37,018 drill-metres and Simbili has been explored by a total of 62 diamond drill holes for 23,038 drill-metres.
The deployment of dedicated DTR equipment by AMDEL expedited the processing of samples for DTR processing and assay, and allowed the completion of this resource estimate in an accelerated timeframe.
SRK carried out the resource modelling in Datamine Studio 3 software, using the dominant logged lithology over the 2m logged interval and the grade characteristics to define the geological domains. A primary magnetite BIF target dominates both Numbara and Simbili with additional lower grade BIF domains being present and a surface Lateritic profile blanketing the two targets.
The resource model used 150 x 50 x 10 m blocks for Numbara and 200 x 100 x 10 m blocks for Simbili, these dimensions being chosen after geostatistical (semi-variograms) analysis, and by taking into account the drill spacing and down-the-hole sample intervals. The grades of the blocks were estimated from the drill data using Ordinary Kriging after the completion of Quantitative Kriging Neighbourhood Analysis on the geological domains to determine the optimum interpolation parameters.
The interpolated block model was run through a Whittle optimisation process using reasonable operating and processing cost parameters and the resulting Mineral Resource estimate being restricted to material falling within the Whittle Shell representing a metal price of US$0.80 per dry metric ton unit for magnetite pellets. Table 1 shows the resulting Mineral Resource estimate for Tonkolili of material that can be assumed to have a reasonable prospect for eventual economic extraction, as stipulated by the JORC code.
This material is restricted to the primary BIF domains and does not include the surface hematitic laterite.
All resources are reported on an in-situ dry tonnes and grade basis.
Table 1: Mineral Resource Statement: Tonkolili Project, Numbara and Simbili Prospects
|
Deposit |
Resource Category |
Billion Tonnes (Bt) |
Fe % |
SiO2 % |
Al2O3 % |
P % |
Mn % |
CaO % |
MgO % |
TiO2 % |
Mass Recovery % |
|
Numbara |
INDICATED |
1.6 |
30.9 |
44.1 |
4.9 |
0.05 |
0.4 |
2.3 |
1.8 |
0.2 |
29.3 |
|
INFERRED |
0.7 |
27.6 |
46.6 |
6.1 |
0.06 |
0.4 |
2.6 |
1.9 |
0.2 |
25.9 |
|
|
TOTAL |
2.3 |
29.9 |
44.8 |
5.2 |
0.06 |
0.4 |
2.4 |
1.8 |
0.2 |
28.2 |
|
|
Simbili |
INDICATED |
1.2 |
31.5 |
44.0 |
3.5 |
0.05 |
0.3 |
2.6 |
2.3 |
0.1 |
32.6 |
|
INFERRED |
1.2 |
28.2 |
46.8 |
4.8 |
0.05 |
0.3 |
2.6 |
2.3 |
0.2 |
27.9 |
|
|
TOTAL |
2.4 |
29.9 |
45.4 |
4.1 |
0.05 |
0.3 |
2.6 |
2.3 |
0.2 |
30.3 |
|
|
Combined |
INDICATED |
2.8 |
31.2 |
44.1 |
4.3 |
0.05 |
0.4 |
2.4 |
2.0 |
0.2 |
30.7 |
|
INFERRED |
1.9 |
27.9 |
46.7 |
5.3 |
0.05 |
0.4 |
2.6 |
2.1 |
0.2 |
27.1 |
|
|
TOTAL |
4.7 |
29.9 |
45.1 |
4.7 |
0.05 |
0.37 |
2.5 |
2.1 |
0.2 |
29.3 |
|
|
Magnetic Concentrate |
67.8 |
4.8 |
0.5 |
0.005 |
Results are rounded to one decimal place (except Phosphorous).
SRK has classified 2.8Bt or 60% of the resource as an Indicated Mineral Resource in terms of the JORC code and notes that the remaining Inferred Mineral Resource, reported above the Whittle pit shell could be reasonably expected to be upgraded to the Indicated category with additional drilling on the existing drill grids.
SRK also notes that Numbara is open at depth and along strike, and Simbili is open at depth with the Marampon prospect providing the northern extension to Simbili.
SRK's full resource estimation report will be made available the week commencing 9 February 2009 on the Company's web-site at www.african-minerals.com.
ONGOING EXPLORATION PROGRAM
Numbara & Simbili
Integration of LiDAR topographic data scheduled for collection in February 2009 will allow for the reporting of the surficial hematitic laterite cap overlying the BIF mineralisation. The mineral resource will therefore be revised and updated upon receipt of these data.
Marampon Prospect
Systematic drilling of the Marampon prospect commenced mid-January 2009 using two diamond drill rigs to further test a high priority BIF hosted magnetite target identified by geophysical modelling of magnetic data and later confirmed by reconnaissance drilling completed in late 2008. Comparison of the magnetic signature and geological properties of Marampon with Numbara / Simbili suggest that the likely BIF hosted magnetite target deposit could contain in the order of between 400 and 600 million tonnes. While this tonnage range is conceptual in nature, and while there has been insufficient exploration to define a Mineral Resource and that it is therefore uncertain if further exploration will result in the determination of a Mineral Resource, in the Company's opinion the Marampon prospect offers the significant potential to further expand the total magnetite hosted iron resource over and above that which is reported in this press release.
Kasafoni
Semi-quantitative modelling of ground magnetic data collected to the North of the existing Numbara resource reported in this press release has generated a modelled magnetic target with high susceptibility and a strong demagnetisation high, similar in characteristics to Numbara, and considered to represent a magnetic BIF target between 500m and 600m thick. This is interpreted by AML geophysical staff to confirm that Kasafoni features a fault offset continuation of Numbara mineralisation to the north of Numbara. Reconnaissance drill testing of this target will be required pending completion of drilling at Marampon.
Metallurgical Testing
A comprehensive metallurgical testing program is underway to assess the upgradability of the hematitic laterite cap to a Direct Shipping Ore product, and to assess the optimal processing strategy to upgrade the magnetite concentrate to a premium saleable product.
Commenting on the Resource Estimate, Frank Timis, Executive Chairman of AML said:
"We have now confirmed a world class magnetite iron ore resource at Tonkolili which complies fully with industry-recognised "JORC" standards. We are very excited that Tonkolili is turning out to be one of the largest iron ore discoveries in West Africa. The hematite rich cap offers significant further upside to the reported resource and provides the potential to generate early cashflow. African Minerals is well positioned to accelerate the project to pre-feasibility study stage with the development of key rail and port infrastructure, over which the Company has a 99 year lease with the Government of Sierra Leone. This, alongside the recruitment of senior executives with significant iron ore experience such as Alan Watling, places us in a strong position to become a significant iron ore producer supplying European, American and Chinese markets".
Qualified Persons
The information in this press release that relates to Mineral Resources is based on information compiled under the direction of Mr Howard Baker, who is a Member the Australasian Institute of Mining and Metallurgy ("AusIMM").
Mr Baker is a full time employee of SRK and has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2004 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves'. Mr Howard Baker has reviewed this press release and consents to the inclusion in the press release of the matters based on his information in the form and context in which this appears.
The information in this press release that relates to geological exploration is based on information compiled and reviewed by Marcus Reston, who is a Fellow of the Geological Society of London ("FGS"), and a Member of the Australian Institute of Geoscientists ("AIG"). Mr. Reston, Project Manager: Tonkolili Iron Ore, is a full-time employee of the Company and meets the requirements of a "Qualified Person" under the AIM Guidance Note on Mining, Oil and Gas dated March 2006. Mr. Reston has reviewed this press release and has consented to the inclusion in this press release of the matters based on his information in the form and context in which this appears.
A full version of this announcement, including technical diagrams and a comparison of the Tonkolili resource against other recently published African Iron resources, can be found by using the following link:
http://www.african-minerals.com/Doc/pdf/RNSDocuments/Tonkoliliresourceanncmt-fullversion.pdf
Glossary of key terms:
|
Banded Iron Formation ("BIF") |
Sedimentary rocks that are typically bedded or laminated composed of layers of iron oxides and quartz or chert. |
|
Mineral Resource |
A concentration or occurrence of material of intrinsic economic interest in such form or quantity that there are reasonable prospects for eventual economic extraction. |
|
Indicated Mineral Resource |
An 'Indicated Mineral Resource' is that part of a Mineral Resource for which quantity, grade or quality, densities, shape and physical characteristics, can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough for geological and grade continuity to be reasonably assumed. |
|
Inferred Mineral Resource |
The part of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a low level of confidence. It is inferred from geological evidence and assumed but not verified geological and/or grade continuity. It is based on information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes which may be limited or of uncertain quality and reliability. |
|
Davis Tube Recovery |
An analytical technique used to separate ferromagnetic and non-magnetic fractions of a sample. This equipment is ideally suited to establishing the recoveries likely from a magnetic separation process. |
|
LiDAR |
Light Detection and Ranging: High accuracy, high resolution elevation data where a laser is used to measure the distance between the sensor and the ground surface. |
|
Ordinary and Quantitative Kriging |
Geostatistical techniques used to interpolate values at unobserved locations on the basis of statistical observations at nearby locations where values are known. |
|
Whittle Optimisation |
A process using the Whittle mining software package that designs and optimises an open pit shell. |
|
Magnetite |
Black, magnetic iron oxide with chemical formula Fe3O4 |
|
Hematite |
A non-magnetic oxide of iron with chemical formula Fe2O3 |
|
Lateritic cap |
A surface or near surface accumulation of chemically stable minerals found in areas of tropical weathering. |
|
SiO2 |
Silicon dioxide (silica) |
|
Al2O3 |
Aluminium oxide (alumina) |
|
P |
Phosphorous |
Enquiries:
|
African Minerals Limited |
Tel: +44 (0) 1481 726833 |
|
Frank Timis Alan Watling |
|
|
|
|
|
Canaccord Adams Limited |
Tel: +44 (0) 20 7050 6500 |
|
Mike Jones Robert Finlay |
|
|
|
|
|
Mirabaud Securities Limited |
Tel: +44 (0) 20 7878 3360 |
|
Rory Scott |
|
|
|
|
|
Citigate Dewe Rogerson |
Tel: +44 (0) 20 7638 9571 |
|
Martin Jackson |
|
|
George Cazenove |
Related Shares:
AMI.L