Taruga Minerals Ltd (ASX:TAR) has topped its recent discovery of clay-hosted rare earth elements (REE) from surface at Morgans Creek within the 1,500 square kilometres Mt Craig Project in South Australia, this time delivering its highest grade of up to 9,082 ppm total rare-earth oxide (TREO).
The program comprised of 2,156 metres of RAB drilling over 59 drill holes, focused on testing strike extensions of clay-hosted REE mineralisation intercepted at Hydrothermal Hill in 2021 in weathered Yednalue quartzite.
Results from the second batch of assaying returned a very high basket average of 34% MREO, which is significantly higher than the peer average of 25% MREO, with high levels of dysprosium and terbium values.
Significantly, the new assays have extended the mineralised strike by 300% from 1.4 kilometres to 4.3 kilometres and is open.
These results have seen the company's shares increase by as much as 31.25% intraday to $0.042.
Remarkable intercepts
Taruga chief executive officer Thomas Line said: “These are remarkable intercepts. They are by far the highest grades we have seen at Morgans Creek to date, with the highest grade exceeding 9,000 ppm TREO.
"Many of the intercepts start from surface and end in mineralisation with some holes ending in high grade.
"We are excited to return to complete systematic drilling over the Yednalue formation and other new clay-hosted REE targets at Morgans Creek early in Q1 2023.
"We completed metallurgical proxy test-work on REE intercepts at Morgans Creek early in 2022. The results showed a high proportion of readily soluble REEs were extractable in a weak acid solution, supporting a low-cost and simple metallurgical flowsheet consistent with ionically and colloidally bound REEs.
"We are very excited to be working with ANSTO, the world leaders in ionic REE leach metallurgy. We have selected a range of representative samples from Hydrothermal Hill which are on their way for analysis, with initial results expected in late November.”
Standout results
Some of the highlights from Hydrothermal Hill include:
- 43 metres at 1,687 parts per million (ppm) TREO from surface to end of hole (EOH) (40% MREO) including 5 metres at 3,343 ppm (0.33%) TREO from 12 metres, with 1-metre at 9,082 ppm (0.91%) TREO from 13 metres (44% MREO) and 14 metres at 2,979 ppm (0.30%) TREO from 29 metres to EOH, with 2 metres at 7,052 ppm (0.71%) TREO from 29 metres (42% MREO);
- 40 metres at 1,582 ppm TREO from surface to EOH (41% MREO) including 17 metres at 2,636 (0.26%) TREO from 11 metres, including 5 metres at 4,930 ppm (0.49%) TREO from 19 metres with 1-metre at 6,234 ppm (0.62%) TREO from 21 metres;
- 31 metres at 1,444 ppm TREO from surface to EOH (44% MREO) including 2 metres at 2,656 ppm (0.27%) TREO from 16 metres, and 6 metres at 3,903 ppm (0.39%) TREO from 22 metres with 2 metres at 5,760 ppm (0.58%) TREO from 24 metres; and
- 55 metres at 678 ppm TREO from surface to EOH (25% MREO) including 14 metres at 1,230 ppm TREO from 41 metres to EOH with 4 metres at 2,190 ppm (0.22%) TREO from 45 metres.
The mineralised rare earth clays assayed contained low deleterious elements, including low cerium, low thorium and uranium, low calcium and low aluminium, which is highly beneficial for downstream processing of REE concentrates.
Mapped weathered Yednalue quartzite unit looking north from Hydrothermal Hill towards Hydro Hill North.
More drilling to come
Mineralisation is concentrated primarily within the weathered Yednalue formation, which has a continuous strike of over 5.5 kilometres at Morgans Creek with exposures more than 300 metres wide. The vast majority of the strike remains undrilled.
Infill and extensional drill planning is underway as several RAB drill holes are believed to have not reached the base of mineralisation and the holes were ended early due to poor sample return.
Aircore or reverse circulation (RC) drilling will be used for the next phase to drill underneath the RAB drill intercepts, likely commencing in the first quarter of next year.
Other activities in Taruga’s exploration plan include:
- Review of drill results against radiometrics and magnetics from the recent airborne geophysics survey for regional targeting (underway).
- Advanced REE metallurgy and concentrate analysis (Q4 2022 – Q2 2023).
- Drill test other prospective units such as the Wirrawilka limestone.
- Commence JORC resource drilling.
- Phase 3 drilling: new REE targets (Q1-Q2 2023).
Taruga’s current exploration model is to focus on weathered zones of clay and saprolite over the Yednalue Quartzite unit, which outcrops for more than 5 kilometres of strike at Morgans Creek, and a further 5 kilometres of mapped strike in the northern portion of the Mt Craig Project.
The company conducted two rounds of reconnaissance RC drilling at Morgans Creek in 2021, focused on copper targeting.
However, clay-hosted REE mineralisation was discovered in several drill holes at the Hydrothermal Hill prospect, which contained a high concentration of the high-value magnetic rare earth elements. Significant intercepts of REEs have been recorded in sporadic drilling over an area of about 6 kilometres by 2 kilometres.
Taruga believes large volumes of Yednalue Quartzite may be buried under shallow cover, hence, it is identifying further concealed prospects.
Other units in the stratigraphic sequence such as the Wirrawilka limestone are also being investigated using soils geochemistry, magnetics and radiometrics geophysics as the REE mineralisation is likely not constrained to the Yednalue Quartzite.