Highlights
- Detailed geological mapping at Mt Edon pegmatite field completed, Deep Ground Penetration Radar (DGPR) geophysical survey underway
- Geological mapping defined numerous new pegmatite outcrops
- DGPR survey will further refine pegmatite structure knowledge in preparation for drilling
- Drilling planned to commence Q2, 2023, immediately after completion of DGPR survey interpretation and drilling optimisation
Commenting on the detailed geological mapping of the Mt Edon mining tenement, Chief Operating Officer, Simon Phillips said:
“The mapping program carried out across pegmatite outcrops at Mt Edon further enhances EMC’s knowledge of the structural formation, lateral extensions and zoning of LCT pegmatite. The data obtained from mapping and the DGPR geophysical survey assists with effective selection of drilling locations, with drilling scheduled for commencement early next quarter. Completion of the Mt Edon exploration program will be a significant milestone towards 100% ownership of the Mt Edon project”.
Everest Metals Corporation Limited (ASX: EMC) (“EMC” or “the Company”)is pleased to provide an update on exploration activities at the Mt Edon project and announce the completion of the detailed geological structural mapping program at the Mt Edon mining lease (M59/714) near Paynes Find, in the Mid-West region of Western Australia.
BACKGROUND
Mt Edon mining lease (M59/704) is located about 5km southwest of Paynes Find (Figure 1) and covers the southern portion of the Paynes Find greenstone belt, southern Murchison, and hosts an extensive pegmatite field. The geology of the area consists of metamorphosed sediments present with regional greenschist and amphibolite facies metamorphism which foliated, deformed, and recrystallised granitoids intruding Archean ultramafic and felsic to mafic extrusive. Late pegmatite dykes/ sills intrude the mafic and felsic volcanics in a contrasting position to the regional orientation of the northeast-southwest.
The Mt Edon tantalite-lepidolite pegmatites have been described as northern and southern pegmatite and they are composed of albite-microcline-perthite and bright purple lepidolite with a quartz core. Also, sub-ordinate quartz, albite, and muscovite, and rarely zinnwaldite, beryl, hyalite, and columbite, a wall zone of medium grained quartz-microcline-plagioclase, and an interior microcline core with milky-smokey quartz and small amounts of albite, muscovite, and beryl reported[1]. The pegmatite was mined for Tantalum (manganotantalite and alluvial deposits,1969-1974) as well as microcline and beryl in the Goodingnow quarries (northern and southern pits,1975-1978). Beryl was also found at the northern pit, but well crystallised green tantalum and yellow beryl was reported from the southern pit.
In October 2022, EMC entered into an exclusive legally binding farm-in and joint venture term sheet to earn up to a 100% interest in the Mt Edon Project subject to due diligence and shareholder approval[2], which occurred at a meeting held on 24th February 2023. Up to 2.7% Lithium grades (Li2O), tantalum grades up to 1046ppm (Ta2O5), and caesium grades of up to 5057ppm (Cs2O) were reported from rock chip sampling of pegmatite outcrops[3]. The Potassium / Rubidium (K/Rb) ratio of this sampling program reflects the degree of substitution of Rb for K in the mica’s crystal structure and most of the samples are indicative of highly fractionated, and therefore high Li-fertility, pegmatites.
EMC has funded a due diligence work program including a targeted reconnaissance RC drilling program to determine whether to proceed with the farm-in. A total of 507m of drilling was completed in late October 2022. The drilling was conducted from 8 drilling fence lines and included 24 shallow holes with an average depth of 21m. Assays returned encouraging results with elevated Rubidium (Rb) up to 3,670 ppm, Caesium (Cs) up to 354 ppm, Tantalum (Ta) up to 219 ppm, and Lithium (Li) up to 1220 ppm. The maiden drilling program determined the subsurface lithium-bearing potential of the Project area below the weathered zone and indicated that pegmatites have moderate to strong fractionation characteristics. Interpretation of results from the recent drilling program has confirmed the pegmatite samples are anomalous in terms of rare metals by a median factor of around 14 times higher than background host rock and suggest that there are several prospective targets for lithium-bearing pegmatites within the Project area. Based on the results of the due diligence exploration program, the Company exercised its right to farm in and to take 51% ownership in a project[4].
GEOLOGICAL – STRUCTURAL MAPPING
The detailed geological-structural mapping was carried out in early March 2023 over 192.4 hectares, an area of approximately 1.6km by 1.2km (Mining Lease M59/714). This recent geological mapping successfully identified several previously unrecorded LCT pegmatite and quartz bearing veins surrounding. There are several large irregular shaped felsic pegmatites which have intruded into the Paynes Find Greenstone Belt, a northeast trending sequence of mafic, ultramafic, and sedimentary rocks, east-west structures cut these metasediments. Pegmatites in this corridor can be divided into the eastern and western pegmatites. The eastern pegmatites tend to be much wider and are more extensive along strike than those further to the west. Most of the pegmatite’s trend to the northeast but several cleavelandite-bearing pegmatites mapped the trend to the northwest. Small outcrops covered by vegetation and the detailed mapping program increased the number of identified outcrops across the zone of pegmatite at the Mt Edon Mining Lease.
Pegmatites have variable compositions with K feldspar being dominant along the Eastern side of the belt, with many being aplitic pegmatites. The pegmatites of Mt Edon are generally medium grained albite-quartz-muscovite mica zones with segregations of microcline-quartz-muscovite and small pods/blebs of lepidolite (Figure 2, a). The general zonation of the pegmatites are a thin fine grained contact zone, a wall zone of medium grained quartz-microcline-plagioclase, and an interior microcline core with milky-smokey quartz and small amounts of albite and muscovite. Field observations confirm a moderately fractionated pegmatite assemblage with pods of lepidolite and some columbite-tantalite mineralisation. Also, small pods of pollucite – lepidolite – greisen mineralisation were observed within pegmatites of albite-quartz-mica-feldspar composition, subject to confirmation by laboratory XRD mineralogy (Figure 2, b & c).
Pegmatites appear to be a folded sill dipping in variable directions and angles and are connected at depth representing sill and dyke structures. These prospective pegmatites have a northeast-southwest strike of up to 350m and occur along a 1.2km interval of the LCT pegmatite corridor. The width and extent of these outcropping pegmatites suggest further exploration for a better understanding of the subsurface pegmatite pods with the main structure and potential of the LCT mineral system. Larger pegmatitic bodies appear less influenced by the underlying structural trends and fabrics, with many of these bodies cutting both structural fabrics. These larger pegmatitic bodies are interpreted as blowouts related to structural intersections (Figure 3).
Outcrops of pegmatites are highly variable; the largest outcrop of pegmatite is about 2 hectares in size but to a large degree the topography follows the strike and plunge contact with the pegmatite sill layer. The pegmatites have been reported to be up to 43m in true thickness on the northeast side of the Mining Lease but in general, as it becomes distal to the granite pluton it appears to be between 2-8m thick. In the central part of the mining lease, pegmatite forms part of a hill which is cut by a creek. The outcropping extends to a height of at least eight metres above the creek. Albite and lepidolite are found along the edge of the quartz zone. Close to the southern border of the tenement, the pegmatite is about 150 metres long and ranges from 4 to 10 metres in width. Apart from a well-developed quartz core, the pegmatite has a quartz-muscovite (with minor lepidolite) border zone.
It seems the pegmatites are part of the same sill and only appear as an intruded pegmatite dyke due to outcrop along fold noses. Together with the sills, there is numerous smaller stockwork of dykes that intruded along joints and fault lines, but the dominant nature of the pegmatite is sills like with a domal folded structure that might be displaced by a central fault line (Figure 4). Strike dip and plunge of the sill changes along the strike outcrop (NE-SW) and along its plunge which is generally northwest, distal to the granitic source rock that outcrops east and southeast of the Mining Lease.
Interpretation of mapping data combined with the re- interpretation of reconnaissance drilling data has provided a better understanding of thickness and lateral distribution of pegmatites.
A summary of important assessment and reporting criteria used for this Exploration Results announcement is provided in Appendix 1 – JORC Table 1 in accordance with the checklist in the Australian Code for the Reporting of Exploration Results, Mineral Resources, and Ore Reserves (The JORC Code, 2012 Edition). Criteria in each section apply to all preceding and succeeding sections.
DEEP GROUND PENETRATION RADAR SURVEY
The Company reviewed geophysical methods to support developing a better understanding of the subsurface potential of the Project area to optimise the second phase of the drilling program. EMC engaged Ultramag Geophysics to undertake a Deep Ground Penetration Radar (DGPR) geophysical survey to determine new potential subsurface pegmatite pods with the main pegmatite structures and identify zonation within the LCT pegmatite bodies and fractionated zones. DGPR is a cost effectiveness and environmentally friendly breakthrough geophysical radar technique offering images of unparalleled resolution; up to 100m from the surface. Survey profiles were designed perpendicular to the pegmatite trends that had been previously and recently mapped at the surface.
NEXT STEPS
- Deep Ground Penetration Radar geophysical survey underway
- RC drilling planned in Q2-2023
[1] The Mount Edon Pegmatite Field, Paynes Find – Goodingnow, Mineralogical Society of Western Australia, June 2002, Volume 3, Issue 3.
[2] ASX: EMC announcement; TSC Acquires Option Over Highly Prospective Mt Edon Lithium-Caesium-Tantalum Mining Lease Expanding Battery Materials Strategy, dated 13 October 2022.
[3] ASX: EMC announcement; Mt Edon Rock chip Sampling Indicates Fertile Well Developed Rare Element Pegmatite Structure, dated 24 October 2022.
[4] ASX: EMC announcement; Drilling Results Highlight Extensive Well Developed Pegmatite Field and EMC To Exercise Farm-In Rights to Mt Edon LCT Pegmatite Project.
