Background - Graphite on Eyre Peninsula
Lincoln Minerals Limited (herin referred to as Lincoln, LML or the Company) is an Australian minerals explorer and developer, primarily focused on base metals, iron ore and graphite exploration and project development on the Eyre Peninsula of South Australia.
Lincoln's principal graphite projects include the Kookaburra Gully Project, the historic Koppio Graphite Mine and the Kookaburra Gully Extended, Pernella, Campoona Syncline and Gum Flat prospects, each of which are highly prospective graphite resources or prospects. In December 2013 Lincoln announced a maiden JORC Mineral Resource of 2.20 million tonnes (Mt) grading 15.1% total graphitic carbon (TGC) at its flagship Kookaburra Gully project. This is a global Top 10 resource.
Lincoln's Australian graphite projects are located on the Eyre Peninsula of South Australia where graphite resources have historically been produced and which is Australia's premier world-class flake graphite province.
• Kookaburra Gully (2.20 Mt @ 15.1% TGC with potential for 15-40 Mt in the immediate area);
• Kookaburra Gully Extended Exploration Target;
• Koppio Graphite Mine (historic mine - 1.85 Mt @ 9.8% TGC); and
• Gum Flat-Sleaford Mere.
Kookaburra Gully Graphite Project
Following electromagnetic (EM) surveys flown over the Koppio and Cockabidnie-Campoona areas in July 2012, resource definition drilling was completed at the Kookaburra Gully graphite deposit in January 2013 with aircore drilling on a 80m x 40m grid spacing.
The Mineral Resources that have been identified at Kookaburra Gully are set out in Tables 1 and 2 (below). These tables show two alternative calculations (and production strategies) that Lincoln Minerals is currently developing.
Kookaburra Gully Graphite Project upside
The maiden JORC Code 2012 compliant Mineral Resources at Kookaburra Gully reinforce Lincoln's confidence in being able to quickly progress the Company's graphite resources on southern Eyre Peninsula into a high-quality, long life graphite mining and processing operation.
The regional EM survey in the Koppio area identified extensive areas of potentially highly graphitic schist similar to the graphite deposits at Kookaburra Gully and the historic Koppio Graphite Mine. The Kookaburra Gully Extended EM target is over 4 km long with possible fold repetitions and has an Exploration Target (**) of 22-44 Mt at 10-15% TGC (Table 3).
Koppio Graphite Deposit
Following air core drilling at and along strike from the historic Koppio Graphite Mine in April 2014, an Inferred Mineral Resource has been identified as set out in the Table below:
Table 4. Koppio Mineral Resource
|Mineral Resource Classification||Lower Cut-off Grade
|Inferred - Domain 1||5%||1.85||9.76||180,733||2.67|
|Inferred - Domain 2||2%||1.21||3.18||38,560||2.80|
|TOTAL (>2% TGC)||3.06||7.16||219,293||2.72|
Mt = million tonnes TGC =
Total Graphitic Carbon
Kookaburra Gully Graphite Metallurgy
Lincoln Minerals has undertaken rigorous metallurgical bench-scale testing of representative bulk drill and trench samples of Kookaburra Gully graphite to optimise the flotation of graphite and removal of gangue minerals.
In July 2012, LML engaged Parsons Brinckerhoff (PB) to undertake a scoping study for the Kookaburra Gully Graphite Project to establish a conceptual process flow sheet and determine capital and operating costs for mine infrastructure and the process plant. This was followed by a scoping study for a pilot graphite production plant.
The scoping studies put Lincoln another step closer to mainstream commercial output from the Company's world class flake graphite resources on Eyre Peninsula. Lincoln is aiming to have trial processed graphite samples ready and waiting for customer qualification in 2016.
Three 70-100kg bulk samples were collated from drill cuttings and trenches representing, respectively, the upper 50m (Sample A) and 50-100m (Sample B) drill intervals, and outcrops (Sample C) of the Kookaburra Gully graphite deposit. Samples were processed, using a laboratory-scale flotation system, by ALS Metallurgy Laboratories in Adelaide using a bulk water sample collected from the Tod Reservoir near Port Lincoln.
Metallurgical flotation tests on the upper 50m (28-38m true depth) bulk sample from Kookaburra Gully, Sample A, yielded a 91.2% recovery of contained graphite into a concentrate averaging 94.0% C (93.7% TGC). The sample was first crushed to minus 2mm then a 2kg subsample was stage ground to P100 = 600m followed by 4 stages of flotation, cleaning and regrinding. A second sample, Sample B, representing mineralisation below 40m true depth, yielded 98% recovery of contained graphite into a concentrate averaging 95.0% C (94.3% TGC).
Table 5: Kookaburra Gully metallurgical test results for bulk aircore drill samples A and B, and trench samples C and D (drill intervals converted to true depth below ground level)