Eclipse testwork shows high Greenland rare earths recoveries

Eclipse Metals’ intriguing Gronnedal rare earths project in Greenland has cemented its position as a potential key source of the high-value magnet elements, neodymium, praseodymium, dysprosium and terbium, with a clear development pathway.

The conclusion follows recent analytical and mineralogical studies by SGS laboratories in Canada on selected samples, which confirm the presence of rare earth minerals including synchysite, bastnasite and monazite.

Eclipse Metals undertook preliminary shallow trenching and drilling at its rare earths deposit, 3 kilometres east of the Gronnedal settlement in southwest Greenland, before spectacularly updating its mineral resource estimate to 89 million tonnes earlier this month.

The mineral suite comprises an ideal assemblage to meet global demand for valuable neodymium and praseodymium which are key magnet rare earths feedstock needed for the global drive towards electrification.

Testwork samples were obtained from 23 core samples acquired by Eclipse from six historic diamond drill holes put into the Gronnedal deposit in the 1950s to a maximum depth of about 200 metres.

The holes are a key input into the company’s recent transformational update to its mineral resource estimate, which massively hiked the inferred resource to 89 million tonnes at 6363 parts per million total rare earth oxides (TREO).

‘In a time of global supply uncertainty, we’re positioning to deliver strategic critical minerals into Western markets - efficiently and at scale.’

Eclipse Metals executive chairman Carl Popal

Encouragingly, Eclipse says the current 89Mt resource represents no more than about 6 per cent of the known carbonatite body, suggesting extensive growth potential, both laterally and at depth, below the present limit of historical drilling.

The mineralogical work utilised a Tescan integrated mineral analyser, X-ray diffraction analysis and chemical analyses to determine the geochemical and mineralogical characteristics of the samples.

The testwork shows the key rare earth minerals are relatively coarse-grained and demonstrate good liberation characteristics at P80 - where 80 per cent of the sample passes through precisely sized sieves within nominated size ranges.

In this case, synchysite and bastnasite demonstrated a best P80 liberation of 54.4 per cent in a size range from 19 to 205 microns (0.019mm to 0.205mm), and a best monazite liberation of 43.6 per cent from 15 to 110 microns (0.015mm to 0.11mm).

Eclipse’s indicative Gronnedal mineral recoveries of up to 54.4 per cent compare favourably, subject to further testwork, with the other important rare earths projects globally – including the United States’ Mountain Pass, Australia’s Mt Weld and China’s Bayan Obo deposits.

The relatively coarse grain size and high liberation percentages point to efficient flotation and magnetic separation pathways that should only require relatively low-energy grinding inputs.

The studies also showed the mineralisation is highly amenable to primary recovery by conventional flotation, considering its dominant content of the three key minerals, synchysite, bastnasite and monazite.

For other minerals, the tests identified niobium at grades from 40 parts per million (ppm) to a best grade of 4670ppm, which could prove an important value-adding component. Yttrium, which is hosted by minerals xenotime and fergusonite, was also identified in the testwork at levels ranging from 39ppm to 777ppm.

The rare earth elements samarium, dysprosium and terbium were also identified in potentially commercial grades.

Eclipse Metals executive chairman Carl Popal said: “This confirmation of simple, high-liberation rare earth mineralogy at Gronnedal gives Eclipse a clear processing advantage. In a time of global supply uncertainty, we’re positioning to deliver strategic critical minerals into Western markets - efficiently and at scale.”

Synchysite is a group of calcium fluoro-carbonate minerals characterised by one of four structural end members that can include one or two of the rare earth elements cerium, neodymium, lanthanum and yttrium. The suite may also include barium, which is not a rare earth element but can be associated with cerium.

Bastnasite is one of a family of three fluoro-carbonate minerals, which can include either cerium, lanthanum and cerium combined or yttrium and cerium combined. Less commonly, hydroxide may replace the fluorine component.

The most common form of bastnasite is dominated by cerium. Bastnasite and the phosphate mineral monazite are the two largest sources of cerium and other rare earth elements.

Due to its considerable variability in composition, monazite is considered a group of minerals that includes rare earth elements.

The most common variant of the group is cerium-dominant monazite-(Ce), which occurs in small isolated crystals containing cerium, lanthanum, neodymium and thorium.

Four other forms of monazite may contain combinations of these elements and also include samarium, gadolinium and praseodymium.

The Gronnedal resource is contained within rocks of the Proterozoic Eon, the geological period spanning 2.5 billion to 541 million years ago. The Gronnedal Complex intrudes the ancient Archaean basement gneissic rocks in the Gardar Province of southwest Greenland.

Eclipse’s rare earth mineralisation lies within a north-trending 8 kilometre by 3km ovoid body of layered nepheline syenites, which has been intruded by a coarse-grained syenite and a central alkaline carbonatite intrusive body. The intrusive carbonite is the primary host of the rare earths, although they also occur in the enclosing rocks.

With less than 6 per cent by volume of the carbonatite intrusion having been drilled - and then only to relatively shallow depth - plenty of scope remains for Eclipse to expand its resource, including at depth, within the known carbonatite and its surrounding rocks.

Given the tendency for carbonatites to occur in clusters where they have exploited major structures, further potential might also exist in nearby undiscovered carbonatites.

The Gronnedal resource is in the more habitable southern tip of Greenland, which gives it a longer field season, good community services and infrastructure and deep-water access. It also positions the project uniquely between rare earths supply chains in Europe and North America.

The recent testwork has provided preliminary confirmation of Gronnedal’s key mineralogy and metallurgy, which shows potential for considerable resource growth and straightforward, scalable and Western-compatible processing routes.

The project has a distinct advantage of low thorium content but comes without any problematic uranium signature. It has strong ESG advantages compared with many other similar scale projects in its commodity sector.

The latest SGS testwork and research goes a long way to supporting the company’s transition to pre-feasibility metallurgical studies.

The studies will include domain-based composite sampling, bench-scale flotation and magnetic separation trials and leaching tests to optimise the recovery of monazite and bastnasite.

The company is also looking at electron probe micro-analysis (EPMA) studies to refine rare earths deportment models. EPMA works by bombarding a sample with a focused electron beam and analysing the emitted X-rays to identify and quantify the elements present.

Eclipse is planning further metallurgical testwork and drilling to expand its resource to fully realise the potential of its carbonatite complex as the company aims to fast-track its Gronnedal rare earths project towards production-readiness.

Popal says the latest mineralogical information from SGS confirms Eclipse is not just sitting on a rare earth deposit, but on a rare opportunity.

“With its coarse grain-size, high mineral liberation and conventional processing compatibility, Gronnedal’s carbonatite sets the company apart from other more complex deposits globally,” he said.

“These are the same minerals - neodymium, praseodymium, dysprosium and terbium - powering electric vehicle motors, wind turbines and defence systems.”

As well as a technical win, it could be a strategic boon for Australia – which will likely absorb punters’ attentions.

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