Much care, no responsibility taken for any use of presented material. Stay tuned at the end of the presentation for a very special historic magnetics exhibit - “A Very Special Historic Exhibit of the Magic of Magnetics.”
Applied for in October 2020, WA tenement E39/2213 (298.32 square km / 100BL) was granted to RareX on 18/07/2023.
There has been very limited exploration of the tenement but current understanding suggests the possibility of a “large (probably Paleoproterozoic) carbonatite magmatic system”, gold, base metals, as well as a conceptual gold trend inferred to be approximately 15km in length. Previous exploration to the immediate north offered “the potential for a significant Archean gold system”, which was not found at that location.
The tenement sits about 90km from the Tropicana gold mine, 150km from the Gruyere gold mine and 130km from the Sunrise Dam gold and Mt Weld rare earth mines.
E39/2213 - Magnetic Anomaly (tenement within yellow lined area) E39/2213 - 1:100 000 Linear Structures (thin black lines) For distance context, the eastern border of the tenement is 27.71km.
E39/2213 - Magnetic Anomaly 1VD (same scale as above)
E39/2213 - Multiscale edges from Magnetics (same scale as above)
High resolution magnetics view from an earlier company. Approximate tenement borders only and not the same scale as the above images.
An alternate magnetics view. Approximate tenement borders only and not the same scale as the top images.
Total Magnetic Intensity Grid. Red = High. Approximate tenement borders only and not the same scale as the top images.
Though dark (the image has been brightened to better show contrast) and not to scale, this is the magnetic pseudogravity grid of the large magnetic anomaly at the bottom of E39/2213.
There are 5 concentric layers that spread outwards. A basic measurement suggests the smallest area is approximately 400m x 500m and the largest area is approximately 7km x 9km. This overall shape aligns with earlier magnetics interpretations of the tenement (as seen at the bottom of this presentation).
Though dark (the image has been brightened to better show contrast) and not to scale, this image shows the overlap of the pseudogravity and magnetic images of the large magnetic anomaly at the bottom of E39/2213. This aligns with the early magnetics interpretations at the bottom of this presentation.
There is also a smaller area of highlighted pseudogravity at the top of the tenement (not shown) which overlaps the tenement’s northern-most magnetic anomaly.
* 5 Holes of Drilling
1 Diamond Hole A substantial circular magnetic anomaly was resolved by a 1982 airborne magnetometer/spectrometer survey, together with 3 subordinate circular anomalies.
The [surveyed] prospect was a conceptual exploration target centred on a large TMI (total magnetic intensity) anomaly that dominated the local area. The prospect was identified because of its complex structural setting and contrasting geophysical response.
In late 1982, a single diamond hole was drilled to test the main part of this magnetic anomaly. The hole intersected the Archean basement at 381m down-hole and was terminated at 423.4m. The upper section drill hole went through surface sand and then grey, clayey-shale (Permian Patterson Formation) before reaching Archean basement at 381m depth (down-hole). Below 381m, the drill hole encountered a matrix supported breccia before passing into highly- magnetic “iron-stone” until the end of the hole.
During or before 2011, inversion processing and forward modelling of the magnetic data (Southern Geoscience) confirms the drill detected depth of this unit and suggests a thickness of ~1,000m. The magnetic anomaly at the site appears to be associated with a magnetic “ironstone” formation, the top of which was intersected in drill-hole.
The original drill log reports the matrix supported breccia is comprised of mainly sub-rounded chert fragments and lesser amount of a pale green sericite + chlorite rock ex-volcanic rock. The matrix is soft and maroon in colour (weathered chlorite) and is hematitic in nature. There is some chlorite + carbonate alteration along shears and hematite + patchy fracture controlled hematite + calcite is noted. Underlying this breccia unit is a magnetite + chert iron stone with honey coloured siderite (iron carbonate) and chlorite alteration. Gold is present in geochemically anomalous levels associated with elevated levels of copper and zinc.
[The anomaly] appears to be a large ironstone formation that is located in a complex and significant tectonic setting with evidence of local magmatism.
The location of the drilled diamond hole can be seen in the magnetics at the bottom of this presentation.
Drilling log for the diamond hole from 400m down.
Another source suggests, “At about 29°35'S 123°35'E, BHP drilled a vertical hole (No 2A), 423.4m deep to test a large circular magnetic anomaly. Very magnetic banded iron formation is reported for the section from 412 to 423.4m, beneath 31m of conglomerate overlain by (?Permian) grey shale. This information comes from Open File Item 2404 which also reports to the effect that ultramafic and mafic rocks were also found by drilling, and that none were recognised as being kimberlite or as having kimberlitic affinities.” - https://geodocs.dmirs.wa.gov.au/Web/documentlist/10/Report_Ref/A42741
4 RC Holes Located along the central western side of the tenement and to the NW of the main magnetic anomaly, there have been 4 RC holes drilled - each represented by a yellow triangle. This drilling was “testing the depth of oxidation and the potential concentration of mineralisation in the centre of the gravity body”.
Background to the initial 2013 RC drilling [2 holes] The …rare earth (REE) target is associated with what appears to be a large carbonatite magmatic complex with an associated composite geochemical anomaly, extending over 64 square kilometres. Multi-element MMI soil sampling was undertaken on a staggered 500 m grid.
Areas of high concentrations of REE's from this reconnaissance survey were selected for infill sampling (100m staggered grid). A coincident and focused area of highly anomalous levels of light, medium and heavy REE's was detected in an area with dimensions of 1,500 m x 2,000 m. This area is a priority drill target and situated within a larger magmatic system that remains open to the north and west. The composite geochemical anomaly is typical of that found in carbonatite-REE systems and the Bear Lodge REE project in the USA provides a good exploration analogue. The project lies in an underexplored area proximal to Burtville-Yarmana terrane boundary.
Drilling as designed to establish the "proof of concept" required to demonstrate that the large carbonatite rare-earth system, inferred from the geophysical and geochemical exploration results, exists in three dimensions. Demonstrating the presence of such an extensive magmatic system has favourable economic implications for this project but also for the wider prospectivity of this 'frontier" exploration jurisdiction. It will also assist in providing a valuable insight into the tectonic and magmatic character of a poorly understood domain, with only limited related geoscientific information.
The …REE project covers an area where no modern exploration (let alone that for rare earths) has been conducted and there is little information on the holistic geology and structure of the area. Exploration and related learning's in this context have been impeded by the Permian post-mineral cover in the area.
The large near surface carbonatite target offers a rare opportunity to better understand the tectonic and magmatic nature of this major complex, and by doing so create new understandings. It will also provide additional information on styles of carbonatite magmatism and mineralisation with the area, which may differ from the known simple intrusive body apparent at the Proterozoic Mt Weld carbonatite REE deposit further to the west.
The project is proximal to Burtville-Yarmnana terrane boundary, (a paleo-cratonic margin). Demonstrating the longevity and post Archean reactivation of the terrane boundary may have important economic implications for exploration of other commodities within other areas along of this prominent regional structure.
Discussion of the initial 2013 RC drilling Carbonatites are largely found in continental rift settings. The East Laverton property is very close to the eastern Burtville and western Yarmana Archean terrane boundary. The emplacement of a large carbonatite-REE complex in this setting during the Paleoproterozoic is consistent with the later reactivation of this major paleo-cratonic margin following cratonisation of the eastern margin of the Yilgarn. The apparent large nature of this system when compared to smaller Mt Weld carbonatite pipe to the west at Laverton would appear consistent with this significant tectonic setting.
The challenge facing the advancement of this REE project is how to proceed from this point, while optimizing the geological information collected from the recently completed drilling programme. The principal items that need to be addressed to further the exploration process: The soil geochemical coverage exceeds 66 km2 and remains open to the west and north and the true extent and nature of the mineral system (e.g. geological and geochemical domains) has not been fully defined and the gaps in understanding the system mean that we do not have a reliable vector to either determine the position of the core of the system, or the fully understand the implications of the recently acquired drilling data.
It was determined that an examination of the general geological and geochemical characteristics of a carbonatite REE system could help in this context. It is noted that carbonatite REE systems appear to be dominantly hydrothermal rather than magmatic in composition. Carbonatites are concentrically arranged complexes that become progressively poorer in silica and iron towards the centre of the system.
In hydrothermal systems, the general order of solubility in hydrothermal fluids appears to be Fe > Cu > precious metals. Early widespread iron (hematite) deposition is typical of oxidised alkaline hydrothermal systems undergoing initial strong dilution by acid and reduced "ambient" fluids. Progressive fluid flows result in a general zoning of a neutral core, an oxidation-reduction (REDOX) from and acid and reduced (iron-rich) outer zone. The strongly oxidised nature of the hydrothermal fluids results an inner zone of hematite and an outer zone of magnetite, depending on local acidity and oxidation conditions.
The high iron and silica content of the material encountered during drilled body (the gravity high) and the correspondingly low magnetic response implies the iron content is dominantly hematite, consistent with the outer zone of an oxidised and alkaline carbonatite system.
Plan of Palabora carbonatite complex showing preferential concentration of iron on outer edge of complex.
2013 – 2 RC holes (two central yellow triangles) Full reporting and assays for REDRC002 and REDRC001 (middle two yellow triangles).A further hole was planned but not drilled. “This drill-hole was designed to test a high-value REE area identified from the previous infill soil geochemical survey. This was the highest individual high REE value. Interestingly, the drill site was demonstrated to be remote to the gravity high.” - https://geodocs.dmirs.wa.gov.au/Web/documentlist/10/Report_Ref/A100241
Rare Earths? Yes… but then less so. But “a potential REE target”? Due to limited earlier exploration, it’s difficult to get a complete understanding of exactly what’s in the ground, particularly in the area covered by the large magnetic anomaly. Here are the previous holder’s announcements for the RE exploration including a lot of geo discussion and initial findings. Proceed with curiosity and caution.
April 2014 - [The company] drilled two RC holes at its REE prospect in May 2013. The drilling tested a carbonatite-REE (rare earth) mineral system that had previously been mapped over a 66 km2 area by soil geochemistry. The drilling confirmed the presence of the carbonatite system at depth. Results from the drilling showed consistent anomalous levels of heavy (HREE) and light (LREE) rare earth elements. However, no ore grade mineralisation was encountered. Regardless, the program demonstrated “proof of concept”, validating [the area] as a potential REE target. …the Company likes the potential of [the] REE… - http://www.rmresearch.com.au/wp-content/uploads/RMResearch-St-George-ASX-SGQ-Apr14.pdf
The 2017 relinquishment report of the area covered by the large magnetic anomaly (including a thorough geological commentary) discusses “a proximal major fault structure”, “a position close to a significant tectonic boundary” and that “the magnetic interpretation of this domain infers the presence of greenstones, but to-date the limited drilling in this area has identified a large (probably Paleoproterozoic) carbonatite magmatic system.” - https://geodocs.dmirs.wa.gov.au/Web/documentlist/10/Report_Ref/A112503
A 2019 technical report offers that “implications for gold mineralisation for what was initially a carbonatite prospect are beginning to be realised. The inferred translithospheric Minigwal fault and the large positive gravity feature in its footwall, along with multi-element drill and soil geochemistry, suggest this area is prospective for gold mineralisation. Overall, the East Laverton area is considered prospective for gold, nickel and base metals. A sulphide and metal rich exhalative sediment surface has been mapped on the western ultramafic contacts. Combined with the rift environment this suggests base metal potential at East Laverton. Importantly, the exhalative sediments sit stratigraphically above the komatiites, which are consistent with a 2.8 Ga nickel event.” - https://geodocs.dmirs.wa.gov.au/Web/documentlist/10/Report_Ref/A122136
A 2021 regional relinquishment report suggests that area covered by 2-3 of the RC drill-holes (away from the primary magnetic anomaly areas), “encountered anomalous levels of REE mineralisation but failed to identify anything at economic concentrations. Further understanding of the internal structure of this system is required. The high Fe + Ti levels encountered in the soil survey and drilling may represent the outer part of this highly oxidised alkaline magnetic system. There is substantial scope to expand this centre further… Further work is required to locate and test the centre of the mineral system.” - https://geodocs.dmirs.wa.gov.au/Web/documentlist/10/Report_Ref/A129626
And a Gold Trend? A [conceptual] major gold trend was identified at E39/2213. It was confirmed by an earlier explorer following a multi-element MMI (“mobile metal ion”) soil geochemical survey focused on an area to the east of the major Minigwal Fault. The MMI survey completed in 2011 confirmed an anomalous gold zone that extended for approximately 5 km of strike and remaining open to the north. This gold anomaly defines the southern end of the gold trend. The total strike length is inferred to be approximately 15 km, of which only a third has been tested. - https://stgm.com.au/pdf/a435fe34-47e2-49ab-8c37-038323789a0c/Golden-Dragon-Major-New-Gold-Trend.pdf
There has not been any drilling in this area.
Gold anomalism in southern 5km section of conceptual 15km trend.
Existing gold anomalies with the inferred extension of the gold trend. Tenement borders are approximate.
It is approximately 90km WSW of the Tropicana gold mine, 150km SSW of the Gruyere gold mine and 130km SE of the Sunrise Dam gold and Mt Weld rare earth mines. Though not illustrated, E39/2213 is approximately 55km NE of the Mulga Tank Ni-Cu-PGE Project.
Exploration to the immediate north of E39/2213 offers that “…geochemical work has shown that the shear was a major conduit for sulphur-bearing fluids, numerous gold-related pathfinder metals, and minor gold mineralisation (thus far). The Dexter Shear is a fertile structure that is effectively unexplored over its >70km strike length. The association of LREE, phosphorous- and thorium-enriched syenites with the Dexter Shear is also significant. If these are mantle-derived magmas, then this further confirms the significance of the Dexter Shear in terms of structural evolution, but also in terms of mineral prospectivity.” https://geodocs.dmirs.wa.gov.au/Web/documentlist/10/Report_Ref/A99478 and https://geodocs.dmirs.wa.gov.au/Web/documentlist/10/Report_Ref/A122517 suggest “the potential for a[n unfound] significant Archean gold system”.
E39/2213 (yellow border) and surrounds with as many geo layers as I could stack while still showing something. The eastern border of the tenement is 27.71km.
*** And now for our special encore presentation: “A Very Special Historic Exhibit of the Magic of Magnetics.” Tenements borders approximate only.
(20min delay)
