Tonkolili Iron Ore Project
World Class Magnetite Iron Ore Asset
Project Highlights
- One of the largest exploration programme in Africa in 2009
- Exploration Licence renewed and increased by 18 sq km
- Davis Tube Recovery testwork yields high grade magnetic concentrates with iron grades at greater than 68% low impurities
- Magnetite Resource Expansion: Working to build JORC Compliant Resource up from 5.1 billion tonnes towards 10 billion tonnes
- Considerable Hematite Potential of approximately 800 million tonnes identified
Tenure
African Minerals received confirmation from the Government of Sierra Leone of the renewal of the Company's Exploration Licence (05/06) at Tonkolili for a two year period with effect from 1 July 2009.
The Tonkolili exploration licence was increased by 17.9 square kilometres, to a total area of 227 square kilometres, by the upgrade of a portion of the adjacent Exclusive Prospecting Licence Number 03/06, also held by the Company.
The increase in tenure was put in place to allow the Company contiguous access to drill-test the full strike extension of the high priority Kasafoni target area.
Core drilling on Simbili prospect at Tonkolili
Laboratory technician operating Satmagan instrument which provides same-day results for on-site geographical interpretation
Exploration
The 2009 exploration programme was highly successful, and confirmed Tonkolili to be one of the largest reported magnetite Iron Ore projects in the world. The programme identified significant and growing Mineral Resource tonnages, high magnetite concentrate grades, and considerable potential for hematite mineralisation overlying the primary magnetite Banded Iron Formation ("BIF") ore bodies.
The first of several significant milestones for the Company was achieved in February with the completion of a preliminary Mineral Resource estimate totalling 4.7 billion tonnes ("Bt") for the Numbara and Simbili deposits based on 60,056 m of diamond drilling.
This considerable resource was updated shortly thereafter in May 2009, when the Mineral Resource estimate was updated to 5.1 Bt with the addition of results from 9,996 m drilling for Simbili and the newly reported Marampon deposit. At this time, 191 drill holes were completed at Tonkolili on Numbara, Simbili, and Marampon for a total of 70,052 m diamond drilling.
The Mineral Resource update in May made Tonkolili the largest reported magnetite Iron Ore project in Africa compliant to the JORC code after just one year of systematic exploration. Full details of the Mineral Resource Estimates are given in the Mineral Resource Statement below.
High grade magnetic concentrates with iron grades in the order of 68% were consistently achieved by systematic Davis Tube Recovery ("DTR") testwork of over 5,000 samples from in situ iron grades of approximately 30%. The high concentrate grades with low impurities coupled with consistent mass recoveries of approximately 29% provide the foundation for detailed pilot scale metallurgical work, well advanced in late 2009, which seeks to demonstrate that Tonkolili iron ores will be amenable to conventional beneficiation techniques for the production of highly competitive iron ore concentrate products.
Mineral Resource Statements
African Minerals appointed independent consultants SRK Consulting (UK) Limited ("SRK") to complete the mineral resource estimation for Tonkolili. SRK has significant and ongoing experience in iron ore including magnetite hosted deposits.
The preliminary Mineral Resource Estimate was completed in February 2009 and covers the Numbara and Simbili deposits. The Mineral Resource update was completed in May 2009 and covers the Numbara, Simbili and Marampon deposits.
Numbara, Marampon & Simbili Mineral Resource Statement
|
|
RESOURCE
CATEGORY |
BILLION
TONNES(Bt) |
Fe % |
SiO2 % |
Al2O3 % |
P % |
MASS
RECOVERY % |
| Numbara |
INDICATED |
1.6 |
30.9 |
44.1 |
4.9 |
0.05 |
29.3 |
| INFERRED |
0.7 |
27.6 |
46.6 |
6.1 |
0.06 |
25.9 |
| TOTAL |
2.3 |
29.9 |
44.8 |
5.2 |
0.06 |
28.2 |
| Simbili |
INDICATED |
1.2 |
31.5 |
44.0 |
3.5 |
0.05 |
32.6 |
| INFERRED |
1.2 |
28.2 |
46.8 |
4.8 |
0.05 |
27.9 |
| TOTAL |
2.4 |
29.9 |
45.4 |
4.1 |
0.05 |
30.3 |
| Combined |
INDICATED |
2.8 |
31.2 |
44.1 |
4.3 |
0.05 |
30.7 |
| INFERRED |
1.9 |
27.9 |
46.7 |
5.3 |
0.05 |
27.1 |
| TOTAL |
4.7 |
29.9 |
45.1 |
4.7 |
0.05 |
29.3 |
| Magnetic Concentrate |
|
1.4 |
67.8 |
4.8 |
0.5 |
0.005 |
|
Table 1: February 2009 Mineral Resource Statement (Reported within a Whittle Shell representing a metal price of 0 USc/dmtu)
|
|
RESOURCE
CATEGORY |
BILLION
TONNES(Bt) |
Fe % |
SiO2 % |
Al2O3 % |
P % |
MASS
RECOVERY % |
| Numbara |
INDICATED |
1.6 |
30.2 |
44.6 |
5.1 |
0.05 |
28.3 |
| INFERRED |
0.5 |
28.6 |
45.7 |
5.7 |
0.05 |
26.5 |
| TOTAL |
2.1 |
29.8 |
44.9 |
5.2 |
0.05 |
27.8 |
| Marampon |
INDICATED |
0.4 |
28.8 |
46.6 |
4.7 |
0.06 |
29.2 |
| INFERRED |
0.1 |
30.1 |
45.8 |
4.0 |
0.05 |
29.9 |
| TOTAL |
0.5 |
29.0 |
46.5 |
4.6 |
0.06 |
29.3 |
| Simbili |
INDICATED |
1.1 |
32.1 |
44.1 |
3.5 |
0.05 |
32.2 |
| INFERRED |
1.4 |
29.0 |
46.5 |
4.8 |
0.05 |
28.1 |
| TOTAL |
2.5 |
30.4 |
45.4 |
4.2 |
0.05 |
30.0 |
| Combined |
INDICATED |
3.1 |
30.7 |
44.7 |
4.5 |
0.05 |
29.8 |
| INFERRED |
1.9 |
28.9 |
46.3 |
5.0 |
0.05 |
27.8 |
| TOTAL |
5.1 |
30.0 |
45.3 |
4.7 |
0.05 |
29.0 |
| Magnetic Concentrate |
|
1.5 |
67.7 |
4.92 |
0.48 |
0.005 |
|
Table 2: May 2009 Mineral Resource Statement (Reported within a Whittle Shell representing a metal price of 0 USc/dmtu)
Notes: All results are rounded to one decimal place, except Phosphorous (P) which is rounded to two decimal places. Any differences between totals and sub-totals are a function of rounding
Magnetite Resource Expansion: "Towards 10 billion tonnes"
Concurrent with the mineral resource definition drilling, the Company completed an appraisal of the remaining portion of tenure as yet untested by drilling. An extensive ground magnetic programme was completed to validate approximately 22 km of untested airborne magnetic targets at the Kasafoni prospect to the North of Numbara, shown in the magnetic image above. Quantitative magnetic modelling of the ground magnetic data strongly inferred the presence of substantial thicknesses of magnetic BIF which required drill testing.
Six reconnaissance diamond drill holes were drilled mid-year to test the newly opened Kasafoni area on the basis of this work. All six core holes confirmed the presence of magnetite BIF up to 220 m thick, and consistent in grade with the BIF present at the three southerly JORC compliant resources of Numbara, Simbili and Marampon.
This highly encouraging reconnaissance work set a major ongoing target for the exploration team; to make Tonkolili the largest JORC compliant magnetite Iron Ore project in the world by increasing the Mineral Resource estimate to 10 Bt. This target is considered to be achievable by independent consultants SRK, who have been fully participant in the ongoing exploration programme.
A major expedited exploration programme commenced in late July using up to eleven diamond rigs for drill operations, and six dozers, a grader, two excavators and two haul trucks for the significant earthworks programme for drill pad preparations of over 300 drill holes. Machinery was under continuous operation 24x7 in what is thought to be the largest exploration programme in Africa for 2009, delivering a total of 53,800m core drilling for 2009.
Geological logging and modelling is approaching completion at the end of 2009 confirming continuous mineralisation along strike at Kasafoni, and additional tonnages at previously noted deposits.
Current expectations are to report a major Mineral Resource update for the magnetite mineralisation in the first quarter of 2010 pending receipt of assays.
The total number of drill holes at Tonkolili as of 31 December 2009 is 556 drill holes for a total of
120,330 m.
Considerable Hematite Potential
A significant thickness and strike extent of hematite mineralisation composed of hematite cap and oxidised transition zone overlies the primary magnetite resources at Tonkolili. Exploration to date suggests that this may comprise in the order of 800 million tonnes of material over Numbara, Simbili and Marampon alone.
Concurrent with the advancement of the primary magnetite resource, exploration is ongoing to define hematite mineralisation of potential economic significance, with additional drilling and geological modelling well advanced to enable the preparation of a JORC compliant mineral resource for these zones.
The hematite iron ore mineralisation has the potential to provide the Company with early project cash flow at Tonkolili dependent on the outcome of the comprehensive metallurgical test-work programme currently under way after the consignment of approximately 20 tonnes of metallurgical sample by charter flight in mid-December 2009.
Senior geologist Joseph Lebbie logging drilll core at Tonkolili
Magnetite Metallurgy
Detailed bench scale metallurgical testwork of Tonkolili magnetite ore was completed including ore characterisation at the CSIRO Iron Ore Group, and further Davis Tube Recovery (DTR) test work at AMDEL.
The DTR method adopted for systematic analysis of drill core was a standard laboratory procedure which was not optimised for Tonkolili ores. Additional DTR work at AMDEL focused on refining the DTR process with the objective of increasing the concentrate iron grade, and minimizing the SiO2 and Al2O3 impurities.
The results of this additional work demonstrated that high grade concentrates containing over 68% can be consistently achieved at a grind size of 25 microns and with a mass recovery of over 30%. Impurities at levels less than 4.5% SiO2, 0.6% AI2O3, and 0.01% P are also achieved.
Detailed metallurgical test work commenced in the third quarter of 2009 on 20 tonnes of Tonkolili magnetite iron ore to identify an optimal mineral processing circuit to produce a high quality magnetite concentrate for sale.
This work features several tonnage scale pilot plant runs to be used to define process design criteria for the Definitive Feasibility Study ("DFS"). Metallurgical test work also included additional ore characterisation by the CSIRO Iron Ore Group, and additional laboratory and industrial test-work by AMMTEC.