Kambale Graphite Deposit
More Graphite Zones at Kambale
- After successful EM survey, which increases size expectations for Kambale Graphite, Castle planned a 46-hole, 4,800m RC drilling campaign with multiple objectives including:
- Testing of several new high priority conductivity zones that may represent zones of graphite bearing schist extending well outside of existing Inferred Resource;
- Extension of known mineralised zones along strike and to depth; and
- Improved understanding of graphite quality distribution.
- 26 holes for 2,660m of a 46-hole, 4,800m RC drilling campaign completed.
- Good correlation between the presence of observed graphitic schists in holes targeted to intersect high-priority EM conductivity zones.
- Graphitic schists intersected in areas not drilled before is very encouraging.
- RC drilling expected to be completed by mid-July.
- Samples will be prepared in Ghana and flown to Perth for assaying.
- Sahara Mining Services appointed to provide independent QA / QC review and JORC Exploration Target range estimate.
- Test work proposal executed with IMO Pty Ltd, Perth.
- CSA Global retained to provide graphite specific technical assistance.
- Subject to assay results, a core drilling program will be designed to recover sufficient material for metallurgical test work and flow sheet development Perth.
- Market commentary continues to indicate continuing strong demand for graphite concentrates and products across most sector uses for the remainder of this decade and in particular the EV battery sector.
Castle Managing Director, Stephen Stone commented: “Our expectation of being able to extend the footprint of the graphitic schist at the Kambale project is proving well-founded on the basis of early observations, having completed 26 holes for 2,660m of the current 46-hole, 4,800m planned.
“This is the perfect time to be advancing Kambale as indications are that the graphite concentrates market will remain very strong for several years to come on the back of the burgeoning production of electric vehicles and the new breed of power storage devices.”
In 2012 Castle commenced graphite exploration on the Wa Project. A historic graphite occurrence about 5km west of Wa was first noted by Russian geologists whilst prospecting for manganese in the 1960’s.
Castle located the historic trenches and completed mapping, RAB, aircore and RC drilling during the first half on 2012. In July 2012 Castle announced a maiden resource estimate for its Kambale Graphite of 14.4mt @ 7.2% C (graphitic carbon) for 1.03mt contained graphite (Inferred Resource). Flotation testwork was conducted on samples of fresh and weathered graphitic schist from the Kambale deposit. Microscopic examination of some flotation concentrates indicated that the graphite flakes were up to 250 microns long.
Exploration has only tested a small part of the interpreted graphtic schist horizon at Kambale and excellent potential exists to substantially increase the current resource. RAB intercepts outside of the current resource area include email@example.com% TGC and 19m @ 7.64% TGC highlighting the prospectivity of the area.
Rougher flotation tests on the fresh and weathered ore samples gave a maximum concentrate grade of over 50% graphite but at low recoveries. In the size fractions coarser than 150 microns, a high proportion of graphite loss to the scavenger tailings was observed. The -150+75 micron size fraction, concentrates 1 and 2 combined, gave a 50% graphite grade at 40% recovery with 30% lost to the final tails. The -75 micron fraction gave the highest recovery (>90%), as expected from a greater degree of graphite liberation from the gangue but grades of less than 30% were achieved. Cleaner and recleaner flotation tests on the -180+75 micron size range failed to improve on these initial rougher tests. A small degree of regrinding of the rougher tail, from 180 to 150 micron top size, improved recovery but did not achieve any significant improvement in graphite grade from the rougher tail.
In order to achieve a high grade of product from the samples supplied, a grind size below 75 microns is recommended. The softness and smearing effect of the graphite on the gangue minerals, drives the need to take small size reduction steps followed by multistage flotation. The sample supplied for testing was RC chips and the RC drilling process itself may increase the smearing effect of graphite over the gangue minerals and any further testwork should be carried out on diamond drill core.
The testwork results from this initial study have shown that an upgrade to just over 50% graphite can be achieved in 1-2 stages of flotation. Further test work would be needed to determine if additional grind-flotation and/or gravity stages could increase the grade to produce a high grade graphite product.
Castle is currently seeking end user/industry participation to advance project development