ProjectsEast Kimberley Graphite Project
East Kimberley Graphite Project
Strategic Entry into the Graphite Market
In 2015, the Company announced a strategic entry into the large flake graphite market by securing a large ground position in the East Kimberley region of Western Australia. The Kimberley region is a proven province for high purity, large flake graphite.
The Corkwood graphite project comprises two tenements covering 151km2. Located in a region of proven coarse flake, high purity graphite mineralisation, the project secures a 25km strike extent of conductive, graphite bearing Tickalara Formation. Drilling carried by the company out in 2015 over part of this target identified thick but low grade coarse flake graphite mineralisation from surface.
During the year Sayona’s primary activities were focused on its lithium projects. However, the company believes that the Corkwood graphite project has considerable value and is seeking partners to explore and develop the project.
Corkwood Graphite Project – Graphitic Schist Hand Specimen
The Company completed a review of historical exploration data in the district, including airborne and ground electromagnetic surveying (“EM”) targeting conductive base metal mineralisation. Graphite is also strongly conductive and many explorers interpreted graphite as the likely cause of the identified anomalism.
Geophysics in the Corkwood area has defined a conductive anomaly over a 20 kilometre strike length, which correlates with surface graphite mineralisation recently discovered in the tenement. Surface rock samples collected from the geophysical anomaly area include:
- Northern Area – up to 6.91% TGC; and
- Southern Area – up to 7.25% TGC.
Geophysics in the Keller area has also defined several conductive anomalies, including one over 5 kilometres in strike extent, coincident with several high-grade graphite occurrences.
The geophysical data represents a low-cost exploration methodology for identifying conductive anomalism in the district.
In Q4 2015, VTEM Geophysics was flown over the Corkwood Graphite Project. This survey identified a strike extent of 25km and highlighted 6 prospect areas.
1. Total Graphitic Carbon (“TGC”)
Prices for graphite vary based on parameters including carbon purity, size, impurities and shape. Flake size is one of the critical elements of graphite pricing, especially for use in the new technology sectors. Jumbo and large flake sizes attract premium pricing and are expected to be in strong demand, driven by the growing use in new technologies such as lithium-ion batteries and super capacitors.
The following table demonstrates the potential for premium pricing for large flake graphite.
Other important economic considerations of large flake graphite include:
- Widest range of end uses when compared to finer and amorphous graphite;
- Substitution is expensive; synthetic graphite prices are substantially more expensive than jumbo flake prices; and
- Larger flake graphite is more amendable to processing into value-added graphite products like expandable and spherical graphite.
Seven East Kimberley project surface rock samples were submitted to Townend Mineralogy Laboratory for polished thin section preparation and petrographic description. Five of the samples were collected from the northern portion of the Corkwood lease, one from the southern portion and one from the Keller area.
The Corkwood rocks are classed as graphite marbles, with the calcite as a replacement mineral of metasomatic origin and related to alteration during weathering. Original feldspar, mica and sulphide have also changed during weathering causing the graphite flakes to be disrupted. The graphite shows good orientation with flakes frequently in excess of 500 micron in length and with widths typically up to 50 micron or more, with a population of finer material within the marble.
The Keller lease sample is a quartz arenite with fine flake graphite identified in the one sample tested.
Corkwood Drilling Program
The maiden drilling campaign at the Corkwood Graphite Project was comprised of 33 holes across 7km of strike for 2,949 metres. The drill holes were sited to target strong anomalies in the VTEM survey. All the assays were completed by February 2016, with results defining broad, near surface coarse flake graphite mineralisation. Six prospect areas were drilled.
The drilling has intersected coarse visual flake graphite mineralisation, with graphite present in every hole. Mineralisation is near surface and has a broadly tabular geometry and shallow dip. Two prospect areas, Windrush and Snowbird, each returned better grades, including:
- 16m @ 5.03% TGC from 13m in SKRC006, Windrush; and
- 54m @ 3.05% TGC from14m in SKRC016, Snowbird.
Results provide encouragement that further drilling can lead to the definition of a mineral resource.
Graphite mineralisation is hosted within a gneissic package of the Tickalara high grade metamorphic basement. The graphite mineralisation occurs as a broad single zone (for example the Firefly and Flying Ant prospects), or within two close spaced horizons (for example at the Windrush, Snowbird and Tempest-Tornado prospects).
The 33 reverse circulation drill holes for 2,949 metres were sited over six prospect areas.
Prospect areas over VTEM
The Windrush prospect intersected the highest grade of graphite mineralisation, with 12.2% TGC recorded from 17-18m in SKRC006. The 8 drill holes were situated on four sections over a strong to moderate VTEM geophysical anomaly and outcropping graphite mineralisation which had been exposed along a pastoral track. The best intercepts are from SKRC006-7, the southernmost holes, and the mineralisation remains open at depth and totally untested along strike to the south. A cross section of the drill fence is displayed below.
Cross-section, Windrush SKRC006-7
The Snowbird prospect also returned encouraging mineralisation. At this location, a single fence of three drill holes was completed to test a conductive VTEM geophysical anomaly coincident with outcropping graphite mineralisation. A cross section of the drill traverse is displayed below, together with a cross section form the Firefly prospect which displays broad thickness to the graphite mineralisation.
Cross-section, Snowbird and Firefly Prospects
Drill chips and composite samples of selected intercepts were collated and submitted for a petrographic study of the graphite flake size and morphology. This work highlighted the coarse flake size of the graphite, with flakes recorded up to 1mm in length (SKRC006 14-15m). The petrography identified that the flakes had been damaged by the RC drilling process and recommends a follow up diamond drilling to provide material for further analysis. The material can also be used for metallurgical and flotation testwork. Flake graphite concentrate from this work can be used for offtake evaluation.
Flake graphite dust from RC drilling. Visibly coarse (Pencil for scale)