Drilling Completed on Eyre Peninsula Graphite Deposits
The drilling program also included limited drilling on Wildhorse Plain Emu Plains copper target and on an Epithermal Au-Ag target also on Wildhorse Plain.
The following summary is based on visual observations only. All assays are expected to be received and collated within the next two to three weeks.
The Sugarloaf graphite deposit, located on EL3711, Carappee Hill consists of two separate fold limbs. Archer's previous drilling has targeted only the western limb and previous estimates of the Exploration Potential were for the western limb only.
Three RC drill holes were completed for an aggregate of 328 drill metres. All holes drilled were to test for graphite in the eastern limb. All holes intersected wide intervals of highly graphitic schist. The graphite and carbon content is unknown. Samples for each hole were taken as described below:
- Hole SLRC12_001 was sampled for graphite from 15m to 29m (14m) and then from 53m to 85m (32m) where a shear was encountered.
- Hole SLRC12_002 was sampled for graphite from 48m to 121m (74m) before passing into a silicified footwall shear.
- Hole SLRC12_003 was sampled for graphite from 48m to 108m (61m) before again intersecting the footwall shear.
The drilling is likely to result in an increase in the Exploration Target for Sugarloaf.
Figure 3 shows the location of the recent drill holes (2012) and previous holes (2008-2011) drilled by Archer on stacked electro-magnetic sections. The apparent folded nature of the graphitic units can be seen with the drill hole traces.
Figure 3 represents electromagnetic data sections over the deposit. Archer has drill tested 1.8km with widely spaced drill holes. The electromagnetic imaging and drill results to date suggest:
- that a broadly folded highly graphitic unit has a potential strike of over 4km.
- the lateral extent of the unit is on average greater than 200m.
- The true width of the unit is approximately 30m.
Samples for carbon content have been submitted and results are expected in approximately 3 weeks.
Previous exploration has shown the Campoona graphite deposit hosts large flake graphite. Petrology on Campoona South samples recorded the graphite size ranging from 5m to 80µm (width) x 300m (length) with an average size estimated by Pontifex of 50µm x 250m. Graphite occurs within "heterogeneous, fine layered quartz-feldspar microgneiss, together with quartz-graphite schist". This includes "minor quartz-clay-sericite-altered ex-sillimanite and scattered small lenses of relatively concentrated graphite."
The presence of sillimanite is important as it reflects a high grade metamorphic overprint has occurred. The metamorphism of a rock refers to the temperature and pressure that the rock has experienced over time. As metamorphic grade increases, higher pressures and temperatures generally enable the development of larger crystals sizes and, in the case of the graphite occurrences tested on Wildhorse Plain, is conducive to the formation of large crystalline flake graphite.
The February 2012 drilling was planned to test the length of the 6km Campoona EM trend targeting the Campoona graphite shaft, the central Campoona trend and the western Campoona area (fig 4). Seven RC drill holes were completed for an aggregate 430 drill metres. Assays are pending.
- CSRC12_001 and 002 intersected weakly graphitic gneiss. Neither hole reached target depth due to drilling difficulties.
- CSRC12_003 and 004 intersected highly graphitic schist from 48 to 73m and from 6 to 16m down hole respectively.
- CSRC12_005 was drilled to test the western limb of Campoona. The hole intersected graphitic gneiss to 38m, highly graphitic schist from 38 - 48m before passing back into graphitic gneiss to the end of hole.
- CSRC12_006 and 007 were drilled within 30m of the historic Campoona graphite shaft. Hole CSRC12_006 intersected weakly graphitic schist to 48m then coarse graphitic schist to a depth of 67m. Hole CSRC12_007, drilled to test the vertical continuity of the graphite in hole 6, intersected graphitic gneiss from 41m to 70m down hole before passing into highly graphitic schist from 70m to 92m. Crystalline graphite could be clearly seen.
Grid 2 Graphite
Five RC drillholes for 213 metres were drilled at Grid 2 where previous petrology had identified flake graphite to 200 micron. Each hole hit widespread but likely low grade crystalline graphite.
Council Pit Graphite
One drill hole was drilled below an outcropping fat lying graphite horizon but passed directly into dolomite.
Emu Plain Copper
A total of 264m was drilled in 2 RC drill holes. Disseminated trace chalcopyrite was observed in some samples. Assays results are pending.
Wildhorse Plain Epithermal Target
Wildhorse Plain hosts an area of probable epithermal alteration made up of fluorite, argillic alteration and minor sulphide. Colloform banded quartz veining has also been observed. Three RC drill holes for 304 metres were drilled to test the area as a follow up to low grade gold anomalism detected by Archer in historic drill core.
To view the figures mentioned in the announcement, please refer to the following link below:
About Archer Exploration Limited
Archer Exploration Limited (ASX:AXE) is an Australian Stock Exchange listed company with 100% ownership of 15 tenements and one Exploration Licence Application all in South Australia covering 6,053 km2.
Archer also has the rights to all minerals other than uranium on EL4693 covering a further 816 km2. Archer's main project is the Campoona Graphite Project which is located within reach of established and major developing infrastructure. It has a JORC 2004 Resource of 5.27 million tonnes @ 7.6 % TC (based on 2% TC cut-off).
Archer Exploration Limited