Highlights
- 21-line kilometres of DGPR survey completed over Mt Edon Mining Lease
- 133 pegmatite-like anomalies have been interpreted and identified, compared to the historically ~30 surfaced mapped pegmatites. Pegmatites structures extend to more than 50m in depth
- Significantly, the resultant DGPR identification of numerous pegmatite dykes has delivered highly prospective drill targets planned for upcoming drilling program.
- Drilling Contractor appointed and drilling to commence in second week May 2023
Commenting on the results of the DGPR survey at the Mt Edon mining lease, Chief Operating Officer, Simon Phillips said:
“The results of the DGPR geophysical program and resultant data at Mt Edon has given the strongest imagery yet of numerous previously undiscovered pegmatite structures. The results have identified over 100 new geophysical anomalies and drilling targets. The data obtained from the DPGR has overwhelmingly supported the Geological team’s expectations as to the potential of Mt Edon and the results have provided a significantly optimised drill targets to support the RC drilling program, scheduled for commencement in second week of May.
Everest Metals Corporation Limited (ASX: EMC) (“EMC” or “the Company”)is pleased to announce results of the Deep Ground Penetration Radar (“DGPR”) geophysical survey at the Mt Edon mining lease (M59/714) located about 5km southwest of Paynes Find, in the Mid-West region of Western Australia. The survey included 21 profiles comprising 19 main profiles at 100m spacing and two extra profiles for a total 21-line kilometres.
BACKGROUND
Mt Edon mining lease (M59/704) covers the southern portion of the Paynes Find greenstone belt in the southern Murchison and hosts an extensive pegmatite field. The detail geological-structural mapping was carried out in early March 2023 over 192.4 hectares, an area of approximately 1.6km by 1.2km. The geological mapping successfully identified several previously unrecorded LCT Pegmatite and quartz bearing veins. 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, with east-west structures cutting these metasediments. Pegmatites appear to be folded sills dipping into variable directions and angles and 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. It seems the pegmatites are part of the same sill and only appear as an intruded pegmatite dyke due to outcrop along fold noses. 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[1].
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 and recognised Deep Ground Penetration Radar (“DGPR”) geophysical survey was a favourable method to determine new potential subsurface pegmatite pods within the main pegmatite structures.
Figure 1: The Deep Ground Penetration Radar equipment at Mt Edon mining lease
DGPR is a geophysical locating method that uses radio waves (radar) to capture images below the surface of the ground. The DGPR method employs high-frequency electromagnetic waves (15,000 Hz average) to map below-ground structures, lithology, or buried ore bodies, similar to seismic. The method is high-resolution and highly site specific. This innovative geophysical radar technique offers images of unparalleled resolution; up to 100m from the surface.
The DGPR geophysical survey at Mt Edon was carried out by Ultramag Geophysics in early April 2023. 19 survey profiles at nominally 100m spacing and two extra feature profiles (50m) were surveyed along lines-oriented northwest-southeast (130°-310°) approximately perpendicular to the pegmatite trends that had been previously and recently mapped at surface and in total 21-line kilometres of DGPR survey was completed (Figure 2).
Figure 2: Layout of the DGPR lines. The lines are spaced every 100m and perpendicular to the general strike of the mapped pegmatites. Two extra survey profiles were undertaken at 50m.
The DGPR works extremely well in this area due to a lack of weathering, crystalline rock, and significant grain size change in target pegmatites to host granite and metasediments. Excellent quality signals from depths of 50m to +100m were recorded. A total of 133 pegmatite-like anomalies have been interpreted including 116 dykes and 17 sills, compared to approximately 30 mapped pegmatites by surface geological mapping. This represents a +300% increase in the number of new pegmatites identified by the DGPR survey, a staggering result given the relatively good outcrop. All anomalies have been evaluated and 35 of them ranked as priority 1 for drilling. Furthermore, pegmatite-like structures and a cluster of layered anomalies have been mapped through the DGPR data. These targets are interpreted to sit along NE-SW‐trending structures that are the control on the emplacement of pegmatites throughout the region (Figure 3).
Figure 3: The DGPR interpretation over mapped pegmatites outcrop at Mt Edon mining lease
The DGPR was successful in identifying subsurface interpreted continuation of outcropping pegmatites down to a depth of more than 50m. The survey could delineate the presence of potential blind pegmatites like targets at depth for follow up assessment (Figure 4, a). Moreover, a series of NE-SW trending sub-vertical features similar to the previously identified pegmatites have been identified in the DGPR data in the central part of the Mt Edon mining lease. These features correlate well with previous reconnaissance RC drilling that has picked up near-surface pegmatites[2].
Additionally, near vertical dyke-like features have been dominated for drilling target optimisation (Figure 4, b & c). This started intuitively based on strong anomalies and was subsequently backed up by the brief analysis above showing a three-fold increase in mineralisation in the dykes compared to the sills. Dykes strike predominantly NE with minor NW trends. This is well supported by the DGPR findings even at coarse 100m line spacing. Most interpreted sills are shallow and near horizontal, some may be stacked. Sills are assumed to be barren or low grade. However, they can be fed in many instances by more dyke like features. Sills trend NNW and have a cyclical wavelength in the NW direction.
Figure 4: The DGPR survey interpretation on 2D vertical slice, profile 0825, shows multiple clusters of pegmatites anomalies (a). Terrain draped profiles of DGPR survey in central part of the Mt Edon tenement (AF0 filter), Sills showed by S and dykes named by P. Profile 1044, example of classic Rocket Engine coarse grained pegmatite anomalies S16, P77 and P78. (b), Profile 1013, showing thick dyke like anomalies and targets P72 and P117 both beneath S9(c)
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.
REVERSE CIRCULATION DRILLING PROGRAMME
The Company received a Program of Work (“POW”) approval from the Department of Mines, Industry Regulation and Safety (“DMIRS”) in mid-April 2023 for its planned drilling programme at the Mt Edon mining lease. Drilling optimisation completed and subsequently EMC appointed a drilling contractor to commence Reverse Circulation (“RC”) drilling campaign in May 2023.
NEXT STEPS
- RC drilling planned in May 2023
[1] ASX: EMC announcement; Mt Edon Project Exploration Update, dated 29 March 2023.
[2] ASX: EMC announcement; Drilling Results Highlight Extensive Well Developed Pegmatite Field, dated 13 January 2023.
 Geophysical Survey Successfully Identifies Previously Undiscovered Pegmatite Targets at Mt Edon){kind=link}