Archer Exploration Mineral Resources for the Central Campoona Graphite Deposit
18.02.2014 | ABN Newswire
Perth, Australia (ABN Newswire) - Archer Exploration (ASX:AXE) report the mineral resources for the Central Campoona Graphite Deposit, with the following highlights:1. JORC Code 2012 Inferred Mineral Resource for Central Campoona of 520,000 tonnes grading 11.6% TC at a nominal cut-off grade of 5% TC. The JORC Code 2012 Resource compares with the previously reported maiden Central Campoona Inferred Mineral Resource of 295,000 tonnes grading 12.5% TC first disclosed under JORC Code 2004 (Archer Exploration Ltd. ASX Announcement 6th December 2012.
2. Further drilling at Central Campoona commenced late in January 2014 to provide infill drilling and to extend the depth coverage below the current base of approximately 50 vertical metres below the surface.
3. Campoona Shaft, located 2 kilometres northeast of Central Campoona had a combined JORC 2004 Code Measured, Indicated and Inferred Mineral Resource as shown in Table 1 below.
Table 1. Campoona 2004 JORC Resource(note) (5%TC lower cut-off grade)
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Area Resource Tonnes Graphite Contained
Category (Mt) (% TC) Graphite (t)
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Campoona Shaft Measured 0.339 14.8 50,200
Indicated 1.056 12.7 134,100
Inferred 0.837 10.7 89,600
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Combined Total Resource 2.232 12.3 293,900
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Note: This information was prepared and first disclosed under the JORC Code 2004 (Archer Exploration Ltd., ASX Announcement 6th December 2012). It has not been updated since to comply with the JORC Code 2012 on the basis that the information has not materially changed since it was last reported.
CENTRAL CAMPOONA - JORC CODE 2012 MINERAL RESOURCE
Resource modeling of Central Campoona was undertaken by AMC Consultants Pty Ltd, an independent mining and resource consultancy, based on information compiled by Archer Exploration geologists.
The Mineral Resources are in accordance with JORC Code 2012 and are set out in Tables 2, 3 and 4 below.
Table 2 Central Campoona Mineral Resource Estimate (>2% Total Carbon Cut-off)
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OXIDE Oxidation State Tonnage Total Density
(kt) Carbon(%)
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0 Oxidised
Graphitic Schist 550 11.0 2.1
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1 Graphitic
Claystone 20 8.1 1.9
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Total Inferred >2%
Total Carbon 570 10.9 2.1
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Table 3 Central Campoona Mineral Resource Estimate (>5% Total Carbon Cut-off)
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OXIDE Oxidation State Tonnage Total Density
(kt) Carbon(%)
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0 Oxidised
Graphitic Schist 504 11.6 2.1
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1 Graphitic
Claystone 16 9.0 1.9
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Total Inferred >5%
Total Carbon 520 11.6 2.1
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Table 4 Central Campoona Mineral Resource Estimate (>10% Total Carbon Cut-off)
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OXIDE Oxidation State Tonnage Total Density
(kt) Carbon(%)
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0 Oxidised
Graphitic Schist 321 14.0 2.1
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1 Graphitic
Claystone 5 12.6 1.9
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Total Inferred >10%
Total Carbon 326 14.0 2.1
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RESOURCE GEOLOGY
The graphite mineralisation occurs as a highly graphitic schist unit within low-grade graphitic proto-gneisses of the Mount Shannan formation. The proto-gneiss is derived from mostly clastic marine sediments of Palaeoproterozoic age.
Carbon probably in the form of methane was encapsulated into the marine sediments. Following diagenesis and uplift the rock suite was metamorphosed to Upper amphibolite-facies which converted the carbon present to crystalline graphite.
Below the topsoil is a thin (~5 m) clay-rich, highly graphitic zone, which passes into highly weathered, porous quartz + graphite + kaolin + tourmaline +/- iron oxides (goethite and hematite). All feldspar has been converted to kaolin +/- illite. Thin clay-rich zones occur probably as cavity fill rather than discrete horizons.
Late-stage cross faulting, has segmented the graphite lodes. This has resulted in a podiform nature to the Central Campoona graphite lodes. The discontinuous nature of the graphite coupled with the drill line spacing of 50m has not provided the geological continuity required to classify the resource above Inferred. Additional infill drilling is occuring to improve the understanding of the geology in Central Campoona deposit, this is anticipated to be completed by the end of February 2014, with assays to be reported during March.
Central Campoona is located 2 kilometres southwest of the Campoona Shaft graphite deposit along the line of the Campoona shear (Figure 1 in link below). In addition to Campoona Shaft and Central Campoona, regional drilling during 2013 located three further occurrences of highly graphitic schist at North, South and East that are considered to be repetitions of the Campoona Shaft and Central Campoona graphitic schist (Figure 1 in link below).
DRILLING, SAMPLING AND ANALYSIS
The Central Campoona JORC 2012 Mineral Resource estimate is based on 140mm diameter RC drilling completed in 2012 and 2013. Drilling was conducted on a nominal 50m x 20m drill spacing to depths of approximately 50 vertical metres and consisted of 64 drill holes for a total 2,900 metres of drilling.
A total of 1,778 drill hole assay data for total carbon were available for this modelling.
nalytical samples were taken from the cyclone at 1 m intervals in a bulk bag. The full sample was split through a riffle splitter mounted under the cyclone to produce a 2-5 kg assay sample. Approximately 15% of the samples were wet.
After visual inspection and geological logging, sample intervals were selected for total carbon assay on the basis of logged graphite. The supervising geologist nominated whether the single metre intervals were submitted to the laboratory or where the graphite content was visually assessed as being low, submitted a 4 metre composite.
As can be seen from Figure 2 in link below the mineralisation at Central Campoona consists of two discrete zones, a southern narrow (<5m thick) zone and a thicker (~10m thick) northern zone which exhibits some discontinuity due to the presence of cross faulting. The area between the southern and northern zones has been sparsely drilled but still has the potential to host the targeted graphitic schist.
Assay batches were despatched to ALS laboratories in Adelaide for sample preparation. Pulps were forward to Brisbane for LECO analysis. Quality control samples were submitted in irregular sequence, and a sample ledger was filled out and kept for each hole to record original sample identity. Sample preparation at the ALS laboratory involved the original sample being weighed on submission to laboratory then dried at 80deg for up to 24 hours. All samples were then crushed to -4 mm and pulverised via LM2 to nominal 80% passing 75µm.
After pulverising, each sample was split to less than 2 kg through a linear splitter and the excess was retained. Sample splits are weighed at a frequency of 1/20 and entered into the job results file.
The pulverised residue was shipped to ALS in Brisbane for LECO analysis. ALS laboratories work to documented procedures in accordance with this standard. Carbon analysis was undertaken by total combustion using a LECO analyser, with a lower detection limit of C = 0.01%. In the LECO process a nominal 0.4 g sample is weighed into a ceramic boat with the exact weight being electronically recorded by the LECO inbuilt computer. The sample is then combusted in oxygen at 1,500-2,000deg C and the resultant carbon dioxide gas formed is quantified using an infrared detection system.
ESTIMATION METHODOLOGY
Total carbon was estimated using inverse distance squared (ID2) methods. Only cells flagged as being within the graphite mineralisation domain (GRAPHITE = 1) were estimated.
Estimation Parameters
The search parameters define the volume from which the samples are selected. In the case of the Campoona Central model estimates, the search volume is an ellipse with dimensions and orientations designed to suit the overall trend of the mineralised zone.
Summary of future work
The current drilling is expected to be completed during March 2014. Once assays are received from this current drilling programme an updated model will be created. The new information will be forwarded to the Competent Person and an updated Campoona Central Resource will be then reported.
To view all tables and figures, please visit:
http://media.abnnewswire.net/media/en/docs/76652-ASX-AXE-782833.pdf
About Archer Exploration Limited:
Archer Exploration Ltd. (ASX:AXE) is a graphite, magnesite, copper, gold and manganese explorer focused on the discovery of world-class ore deposits.
The company has carefully acquired a portfolio of projects, covering an area in excess of 5300 km2, in the highly prospective Gawler Craton and Adelaide Fold Belt regions of South Australia. All projects are 100% owned by the Company.
Archer also has earned the right to 100% of minerals other than uranium on EL4693 Wildhorse Plain located near Cleve on Eyre Peninsula.
The Company's flagship Campoona and Sugarloaf graphite deposits occur in the Cleve district where the Company has tenure of 933km2 in the emerging graphite province.
Archer Exploration Ltd. has an experienced board and management team and has the ability to maximise the potential of the company's world-class projects.
Contact:
Archer Exploration Ltd.
T: +61-8-8272-3288
WWW: www.archerexploration.com.au