Finders updates Wetar copper project
Thursday, June 25 2009 - 06:56 AM WIB
Finders Resources (?the Company?) is pleased to report excellent progress with key aspects of the feasibility study of the full scale development of the Wetar Copper Project in North Maluku province.
Following four months of leaching and production from the large scale test heaps and 5 tonnes per day copper SXEW demonstration plant, the Company has now finalised detailed design parameters for the full scale plant expansion to 20-25 thousand tonnes per annum. The Definitive Feasibility Study is based on the Whim Creek SXEW plant that the Company has an option to purchase from Straits Resources for A$5m.
Copper leaching from full scale test heaps achieving project targets
At the Wetar Copper Project Demonstration Plant, there are three test heaps currently under irrigation, with the aim of demonstrating the feasibility of commercial scale heap leaching of the Wetar massive sulphide copper mineralization (Table 1.)
All heaps are showing excellent percolation characteristics, and are on track to achieve targeted ultimate recoveries of >70%.
Experience to date has shown aeration rates to be a key factor controlling leach kinetics, and copper leach rates have improved markedly from Heaps 1 to 3 with progressive improvements in the aeration systems used. A fourth heap, with a heap height of 8.5m is currently being stacked to evaluate the effect of increasing heap height.
Table 1. Leach Statistics: Week ending 20th June 2009
| ? | Average Height | Tonnes Stacked | Cu % | Contained Copper (tonnes) | Leached Copper (tonnes) | Ave. Days Leaching | Recovery |
| HEAP 1 | 6m | 20,037 | 2.8% | 561 | 162 | 148 | 29% |
| HEAP 2 | 6m | 23,380 | 3.6% | 842 | 267 | 115 | 32% |
| HEAP 3 | 5m | 19,129 | 4.9% | 939 | 271 | 72 | 29% |
As the demonstration stage has progressed, more detailed information regarding mineral composition and recovery rates has allowed fine tuning of the leach kinetic model to reach the stage that the current model will form the basis for the mining schedule and production modelling in the feasibility study.
Positive reconciliation-grade control sampling from test pit mining
Mining of ore for the test heaps was undertaken from two test pits, the principal southern test pit, and a small northern pit. Hellman and Schofield Pty Ltd has carried out a detailed reconciliation between the current Kali Kuning resource block model and the grades indicated by close spaced (average 3.75m spacing) grade control assay data.
A direct comparison between identical volumes for the resource model and grade control drilling for the main southern teat pit is presented in Table 2 below
Table 2. Southern Test Pit-comparison of resource model with grade control results
| Material | Kt | % Cu | Kt_Cu |
| April 2009 resource model | 213 | 3.68 | 7.8 |
| Grade control drilling estimate | 208 | 3.91 | 8.1 |
| Difference | -2.3% | +6.3% | +3.8% |
In addition to the above direct comparison, the grade control drilling for the southern test pit located an additional 60kt of massive sulphide ore, grading 3.6% Cu from outside of the limits of the massive sulphide resource model.
For the smaller northern test pit, situated in highly broken leached and transition zone mineralization, where significant copper losses were suspected in the original resource drilling program, the grade control drilling showed a strong increase in both grade (36%), tonnes (25%) and contained copper (70%) at a 0.5% Cu cut-off grade, when compared to the resource model for the same volume.
Leached and transition material comprise approximately 20% by tonnage and 11% by contained copper for the Kali Kuning sulphide mineralization at a 0.5% Cu cut-off (Table 3). Although this reconciliation applies to a restricted area of approximately 50,000 tonnes, this result highlights the possibility that the copper grade of this portion of the resource may have been significantly underestimated by previous drilling and, as a result, the resource model.
Definitive Feasibility Study (DFS)
Final pit designs for both the Kali Kuning and Lerokis deposits have been completed by Amdad Pty Ltd, and confirm that effectively 100% of the sulphide resource will be recoverable by low stripping ratio open pits. A formal statement of Ore Reserves under the JORC code is scheduled by the end of July, after detailed review of mining costs, leach performance and mining cut-off grades.
As part of the DFS, life of mine heap leach modelling is being undertaken by specialist consultant Simulus Pty Ltd, using metallurgical inputs from Finders metallurgical consultants and mining schedules provided by Amdad. Results of this modelling to date support the potential for sustained production at up to 25,000 t copper /year under realistic mining, stacking and leaching scenarios.
The formal DFS, managed by Ausenco, with design work incorporating the Whim Creek SXEW facility recently optioned from Straits Resources, remains on schedule for review in August.
Finders is actively engaged in discussions with a wide range of groups who have expressed interest in providing project finance for the full scale project, and has also begun preliminary discussions with Ausenco and a range of Indonesian engineering contracting groups capable of partnering in the delivery of the expanded project. (end of edited excerpt)