Doradilla (100% SKY)
The Doradilla Project is located approximately 45km south-east of Bourke in western New South Wales and is considered prospective for polymetallic tin, copper, silver, bismuth, indium and zinc mineralisation. Most recently, SKY has discovered a widespread, and large high-grade REE mineral system in the thick layers of clays over the Doradilla Project.
Mineralisation at Doradilla was discovered in the 1970s after regional magnetic surveys identified the 16km long strike hosted within the extensive Doradilla-Midway-3KEL skarn (‘DMK Line’) The DMK Line extends for the length of over 16km and is a 40-100m wide skarn zone of tin and polymetallic mineralisation and has now also been identified as the host to high-grade REE mineralisation along the entire 16km length of the DMK Line.
Discovery & Early Exploration
Previous exploration has focused heavily on the tin content of the DMK Line, and predominately on the oxide mineralisation which overlies the primary zone mineralisation. Work on the DMK line slowed in the 1980s when the oxide zone tin was found to be metallurgically difficult, however the primary zone tin, in a mineral called Malayaite, has been established as being amenable to smelting in concentrates over 30% Sn and as such remains a potential important source of tin for the future.
Geologically, the Doradilla area lies between the Lachlan and Thompson Orogens with mineralisation associated with the re-assigned Triassic aged Midway Granite, now considered by the Geological Survey of New South Wales to be analogous to the major tin granites in the New England Orogen, where tin was first successfully mined in Australia in the 1800s.
Sky Metals Exploration
In 2019 SKY drilled 4 holes at the 3KEL Target on the north-eastern end of the 16km DMK Line. This program included the first hole to intercept the primary zone at the 3KEL Target in over 35 years, hole 3KRC002. Results included:
- 3KRC002: 6m @ 1.11% Sn & 1.48% Cu from 105m
In 2020 SKY flew a detailed magnetic survey over the DMK Line to target the DMK mineralisation more accurately and in 2021 completed a second program of RC and diamond drilling of the 3KEL Target using this magnetics data. Drilling intercepted consistent, wide and strong tin mineralisation with results including:
- 3KRCD007: 45m @ 0.42% Sn from 35m Including;
10m @ 1.07% Sn & 0.15% Cu from 60m
- 3KRC011: 32m @ 0.42% Sn from 66m Including;
9m @ 0.99% Sn & 0.31% Cu from 81m
- 3KRC012: 37m @ 0.31% Sn from 91m including;
1m @ 4.23% Sn & 0.20% Cu from 121m
- 3KRC009: 14m @ 0.46% Sn from 135m
- 3KRCD010: 4m @ 1.10% Sn & 0.21% Cu from 135m
Then in late 2022, following recognition that the Midway Granite’s chemistry made it prospective for REE mineralisation, SKY reassayed past drill sample for REE. This reassaying discovered thick, high-grade REE mineralisation along the whole length of the DMK Line at all three historic tin deposits, Doradilla, Midway and 3KEL.
- AMW10: 33*m @ 4981ppm (0.50%) TREO from 15m, including; 12m @ 8781ppm (0.88%) TREO from 25m.
- DRAC016: 20*m @ 3179ppm (0.31%) TREO from 16m, including; 2m @ 5657ppm (0.57%) TREO from 18m.
- DRAC020: 10m @ 2894ppm (0.29%) TREO from 38m, including; 4m @ 6023ppm (0.60%) TREO from 44m.
- DRAC023: 24*m @ 2628ppm (0.26%) TREO from 18m, including; 4m @ 3731ppm (0.37%) TREO from 22m.
- AMW23: 26*m @ 2329ppm (0.23%) TREO from 10m, including; 10m @ 3407ppm (0.34%) TREO from 15m.
*Intercept is either open up hole, open down hole, or open in both directions.
Priority Target Area – Midway Granite
The Midway Granite outcrops at surface and has been discovered through geological mapping as well as radiometric and magnetic geophysical data. The area where the granite outcrops also has a wide area around the outcrop where the granite is either more deeply weathered or is under a thin cover sequence, as indicated from the magnetic geophysical data. Therefore, this entire area of multiple square kilometres is prospective for REE mineralisation.
The weathered Midway Granite shows strong geological similarities to the clay hosted REE mineralisation successfully mined for REE over the last few decades in China. The REE mineralogy and, therefore, metallurgy, is more likely to be similar to these systems due to these geological similarities and, as such, is a very attractive target for easily extractable REE mineralisation.
In addition to these possible advantages, the work to date at Doradilla shows TREO grades increase the closer samples are to the Midway Granite. If this relationship continues, then it is possible that higher TREO grades will be discovered in the vicinity of this target area as it is within or immediately adjacent to the Midway Granite.
Samples from the upcoming drilling program will be assayed for REE and a multielement suite to establish the presence of REE mineralisation and characterise the granite phases to aid in vectoring to further mineralisation. On the potential discovery of REE mineralisation, samples will be sent to ANSTO to test for extraction of REE.
SKY plans to continue to advance this project with further drilling and metallurgical test work with the aim of developing 3KEL and the wider Doradilla Project into a vital new source of REE and tin.
In addition to REE and tin, the Doradilla Project also represents a strong exploration target for copper, silver, bismuth, zinc and indium. In particular, the supergene tin- laterite deposits currently identified at 3KEL & Midway have the potential to contain economic levels of copper and zinc mineralisation based on the few holes that have been assayed for these metals. A considerable amount of previous drilling was assayed for tin only, with no systematic exploration carried out for any other metal.
Drilling by SKY and YTC Resources confirmed the tin laterite mineralisation at the 3KEL deposit is also rich in copper, zinc, indium and bismuth. Metallurgical testwork on the copper mineralisation in the oxide at the 3KEL Target show +90% recoveries of copper via acid leaching.