Final Metallurgical Tests Yield Jumbo Flake Graphite and Enhanced Purity for Flinders’ Woxna Graphite Project, Sweden
Vancouver, Canada
Flinders Resources Limited (“Flinders”) (TSXV: FDR) (Frankfurt: 7FL) (OTCPK: FLNXF). Mr. Martin McFarlane, President & CEO is pleased to provide an update on the metallurgical test programs and mine planning from the Woxna Graphite Project in Sweden.
Key points:
- The graphite product mix produced from the metallurgical test work far exceeded historical production purities and flake graphite sizes:
- 18% of the graphite product reported as extra-large or jumbo flake graphite (+250 µm or +60 mesh) with 95% purity. This high value product was never historically commercialised at Woxna;
- 22% of the graphite product reported as coarse flake (+180-250 µm or -60+80 mesh) with a 94% purity;
- 28% of the graphite product reported as medium flake (+100-180 µm or -80+140 mesh) with a 92% purity;
- Overall graphite recovery from the locked cycle test exceeded 96%;
- Mine planning optimization studies have further reduced stripping ratios by 37%;
Mr McFarlane states, “Our patience in awaiting metallurgical test work studies and mine planning optimization has been rewarded. The product mix obtained from the metallurgical work has exceeded our expectations in terms of graphite sizes and purities, and demonstrates Woxna can now produce a premium jumbo flake product. In combination with reduced stripping rates, which will have a positive effect on mining cost estimates, we are now well placed to complete our financial studies for the project.”
Metallurgical Test Work
A bulk sample, together with representative core samples of graphite mineralization from across the Woxna Kringel mineral resource were sent to flotation specialist Aminpro Metallurgical Laboratories (“Aminpro”) in Chile. Aminpro were commissioned to complete a series of graphite processing tests that would lead to an improved process flow sheet optimising graphite flake size, purity and recovery results.
A key goal of the test work program was to improve the purity of flake graphite concentrate when compared to historic production, which ceased in 2001. In particular, the aim was to achieve a minimum 94% purity for a portion of the larger flake sizes, which commands a price premium in the market.
A locked cycle test was performed based on optimised conditions determined from prior grinding and flotation test work. The optimised process circuit involved using a single stage coarse grind with the material passing a 400µm screen before undergoing rougher flotation. The rougher flotation concentrate then underwent 2 stages of cleaning using a mild attrition regrind followed by flotation while the rougher tails underwent scavenger flotation followed by 3 stages of mild attrition regrinding and cleaning. A total of 7 cycles were undertaken yielding good repeatability of results and steady state.
The following table shows the average graphite purity results by flake size for the locked test results and historical production.
Graphite Flake Size | Rougher Concentrate | Scavenger Concentrate | Combined Rougher & Scavenger | Typical Historical Production | |||||
---|---|---|---|---|---|---|---|---|---|
µm | mesh | Retained % |
Purity % |
Retained % |
Purity % |
Retained % |
Purity % |
Retained % |
Purity % |
+250 | +60 | 14 | 95 | 22 | 95 | 18 | 95 | – | – |
+180-250 | -60+80 | 19 | 97 | 23 | 92 | 22 | 94 | 32 | 92 |
+100-180 | -80+140 | 26 | 94 | 30 | 91 | 28 | 92 | 32 | 92 |
-100 | -140 | 41 | 89 | 25 | 87 | 32 | 88 | 36 | 85-89 |
Overall graphite recovery from the locked cycle test exceeded 96% with approximately 44% of the recovered graphite reporting to the rougher concentrate and 56% to the scavenger concentrate. Aminpro believe, from their experience, that the test results are conservative and when in full production further improvements in flake size distribution and purity of the finer graphite sizes are likely.
Mining Plan
Golders of Sweden have further optimised the Woxna mine plan using the industry recognised Whittle optimisation software. Running scenarios to maximise discounted net cash flow, Whittle produced 1.3 million tonnes of mineralised rock mined at 10.9% graphite with a strip ratio of 3.8:1. This represents a 37% improvement on the 6:1 strip ratio produced from earlier mine planning models.
Running additional scenarios enabling Whittle to vary cut-off grade produced an optimum scenario at 2.0 million tonnes of mineralised rock mined at 10.5% graphite with a cut-off grade of 5.9% (previously 7.0%) while stripping ratio was moderately higher at 5.3:.
Mining plan work is now effectively complete for the purposes of the Preliminary Economic Assessment.
Preliminary Economic Assessment
The metallurgical test work is now complete and work has commenced on finalising the Preliminary Economic Assessment of the Woxna graphite project.
The metallurgical test work results are being used to optimize a new process flow sheet that is less complex than the process used when Woxna was last in production.
New and reused equipment will be specified for the final modified process flow sheet. Operating and capital costs will then be calculated as will revenue based on the metallurgical test results.
It is anticipated that the Preliminary Economic Assessment of the Woxna graphite project will be completed approximately mid August.
Chris Stinton, BSc (Hons) (Minerals Engineering), CEng MIMMM, Senior Metallurgist with GBM Minerals Engineering Consultants of the United Kingdom, an independent consultant to the Company, is the qualified person as defined under National Instrument NI 43-10 and has reviewed and verified the metallurgical results referenced within this release.
On behalf of the Board
“Martin McFarlane”
Martin McFarlane, President and CEO
For more information contact:
Jim Powell +1 647-478-5806
info@flindersresources.com
About Flinders Resources
Flinders Resources Ltd. (TSXV: FDR) (Frankfurt: 7FL) (OTCPK: FLNXF) owns 100% of the Woxna Graphite Mine, a unique and strategic European graphite project in central Sweden. The Woxna Mine, with rated capacity of 10,000+ tonnes per year of flake graphite, operated from 1996 to 2001 when production was halted due to falling graphite prices. Since then, the Woxna Project has been held on care and maintenance.
Today graphite prices are significantly higher than in 2001 underpinned by strong growth in graphite demand driven by a combination of steady growth in traditional uses such as steel production, lubricants, brake linings and batteries as well as double digit growth from new applications, in particular batteries for portable electronics and hybrid and electric vehicles.
Materially better graphite price today and forecast growth in graphite demand is why Flinders is evaluating re-starting the Woxna graphite mine. Flinders’ Woxna mine is substantially funded, fully permitted, constructed and with moderate capital investment ready to be brought back to production. The Woxna Project is unique due to its high quality large graphite flake, long life expandable resource, first class existing infrastructure, potential to upgrade to value added lithium battery graphite and its strategic position within the European Union.