Perth-based explorer Emu NL has kicked off its maiden drilling campaign at its 100 per cent-owned Condingup clay-hosted rare earths project, near Esperance on Western Australia’s scenic south coast.
The 3000m air-core (AC) program will test rare earths enrichment within clay traps imaged by passive seismic, adjacent to and overlying the fertile Booanya granite, which the company says may have leached its pay into the clays.
The Booanya granite exists as outcrops in parts of the Condingup tenement and has previously produced rock chips testing as high as 2124 parts per million total rare earth oxides (TREO).
Magnetic rare earth oxides (MREO) made up about a quarter of the TREO grade from Emu’s outcrop sampling efforts in December last year and heavy rare earth oxides (HREO) made up 12.7 per cent.
MREO are the sum of the oxides of neodymium, praseodymium, dysprosium and terbium and are commonly used in the manufacture of high operating temperature permanent magnets that are notable for their durability and strength.
Neodymium-praseodymium oxide is an input for magnets that have 10 times the strength of conventional magnets and there is currently no known substitute. The oxide represents about 90 per cent of the value in rare earths markets and is currently trading at a spot price of about $60 per kilogram.
HREO are made up from the oxides of about 10 elements and also form critical inputs in the manufacture of hybrid cars, fiber optics and medical devices.
Emu says the upcoming drillholes will range from between 30m and 100m deep and will specifically target a network of wide, clay-filled channel bodies that abut the granites throughout the land package. Interestingly, management says a large channel fill feature, adjacent to a Booanya granite intrusion, is more than 6km wide and at between 20m and 100m in depth and presents a large-scale walk-up clay-trap target.
The company’s rock-chip sampling of the Booanya granite has produced encouraging results, with assays including 1242ppm, 1090ppm and 1206ppm TREO. Some legacy rock chips have gone 1142ppm and 1263ppm TREO, as well as 17 more results between 450ppm and 1000ppm.
Emu is one of several companies actively exploring for rare earths in WA’s south.
OD6 Metals has had recent success about 35km to the north-east of Emu’s land, after drilling results at its Splinter Rock project turned some heads.
Its assays came back with impressive TREO concentrations up to a whopping 6605ppm. Some of the best results include 69m at 1483ppm TREO with 21.1 per cent MREO from 24m and 66m at 1516ppm TREO with 20.2 per cent MREO from 15m.
On the back of its drilling campaign, OD6 announced a maiden mineral resource estimate for Splinter Rock of 344 million tonnes at 1308ppm TREO at a 1000ppm cut-off grade, with high-value MREO making up about 23 per cent of the TREO grade.
Emu says its geologic model at Condingup is similar to that at Splinter Rock, both targeting the rare earths-enriched weathered profile adjacent to the fertile Booanya granite intrusions. Management says it has pegged all of the ground where the granite bedrock contacts the clays and believes it has a strong chance of making a similar-sized rare earths discovery to OD6.
Clay-hosted rare earths deposits provide several distinguishing features when compared to their hard rock spodumene counterparts. The clays are soft, meaning cheap AC drilling is possible and only negligible blasting required. They also sit shallow, making them suitable for open-pit mining, have a low strip ratio and do not require crushing or milling.
Clay-hosted deposits often contain a higher proportion of MREO and HREO, which were both elevated in Booanya granite outcrops within the Condingup project area. With assays from the AC program due back in early October, Emu could soon be pumping out some lengthy steps forward.
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By Andrew Duffy
