International iron ore company Centaurus Metals Limited announced an updated JORC Mineral Resource estimate for its flagship Jambreiro Iron Ore Project in Brazil, including a substantial increase in the Measured Resource estimate which confirms the robustness and quality of the project.
The JORC Resource estimate (combined Measured, Indicated and Inferred) has been increased to 125.2 million tonnes grading 26.7% Fe (see Table 1) (previously 116.5 million tonnes grading 26.8% Fe) with the key change being a significant increase in the Measured component (friable and compact itabirite) to 46.7 million tonnes grading 28.3% Fe including 37.6 million tonnes of friable material grading 28.8% Fe.
The new Resource estimate, which reinforces the consistency of the grade and volume of mineralisation at Jambreiro, will underpin the current Bankable Feasibility Study which is due for completion in September this year, paving the way for financing and development of the project to proceed.
Importantly, the Jambreiro Project now has an estimated 65.7 million tonnes grading 27.7% Fe of friable itabirite mineralisation, of which 53.7 million tonnes grading 28.8% Fe is classified in the Measured and Indicated categories. This represents a slight increase in both iron grade and volume from the September 2011 resource (52.1 million tonnes at 28.0% Fe).
Based on the Reserve estimation work completed at the time of the Pre-Feasibility Study in November 2011, Centaurus expects to be able to convert a very high proportion of the Measured and Indicated Friable Resource into Ore Reserves, on delivery of the BFS which is focused only on friable mineralisation.
Beneficiation testwork on resource grade mineralisation has so far demonstrated that both friable and compact mineralisation types can be beneficiated to a high-quality saleable product to suit various customers and markets, ranging from the premium 67% Fe with less than 2% silica to the more economical 63% Fe with less than 5% silica.
Further, the beneficiated product from Jambreiro will have extremely low phosphorus grades between 0.01% and 0.02% P with low alumina grades ranging between 0.7% and 0.9% Al2O3.
The Company is currently running an extensive pilot plant testwork program as part of the BFS on 50 tonnes of friable mineralization, including both outcrop and samples extracted from drill holes, in order to finalize the process flow sheet for costing purposes and to produce a representative product for marketing purposes with the domestic steel mills. The pilot plant run is also testing additional circuit options which will potentially further enhance the product quality range at reduced operating costs. The results of this pilot plant work are expected in mid-July.
The resource update incorporates the results of a successful in-fill RC drilling campaign undertaken this year which targeted the definition of Measured Resources to support the first 4 to 5 years of production from the friable project. The Measured and Indicated Resource component for friable mineralization now comprises an estimated 53.7 million tonnes grading 28.4% Fe with the Measured Component standing at 37.6 million tonnes grading 28.8% Fe. The Measured component alone is expected to now comprehensively cover the first six years of production.
The in fill program confirmed the consistency of the iron grade and volume of mineralization at the Tigre and Cruzeiro Deposits, both along strike and down-dip. Exploration drilling also confirmed the extension of the Cruzeiro Deposit to the south, which approaches the Tigre Deposit. It is expected that this will result in the two pits eventually being joined.
Highlights
1. 246% increase in Measured Resource to 46.7Mt @ 28.3% Fe with the overall Jambreiro resource estimate increasing to 125.2Mt @ 26.7% Fe.
2. Total Measured and Indicated Friable Resource estimate lifted to 53.7Mt @ 28.4% Fe with the Measured Friable Resource estimate alone, of 37.6Mt @ 28.8% Fe, underpinning the first six years of mining.
3. In-fill drilling and updated resource confirm the strong consistency of widths and grades of mineralization at Jambreiro.
4. Updated resource to underpin the Bankable Feasibility Study (BFS), with high conversion of Measured and Indicated Resources to Ore Reserves expected when the BFS is finalised.
5. Extensive bench scale testwork and initial pilot plant testwork shows that a high-grade (+65% Fe), low impurity sinter product can be produced from Jambreiro ore - new 50-tonne pilot plant testwork program underway.
The south-eastern portion of the Tigre Deposit and the Cruzeiro Deposit both host relatively high-grade friable mineralization that dips sub-parallel to the natural surface (see Figures 4 to 7). These zones are ideal for a start-up mining operation with a low strip ratio targeting high-grade ore as a source of early production in order to maximise cash flow in the initial years to facilitate rapid payback of capital.
Source - Centaurus Metals
(www.steelguru.com)
