ASX-listed Eclipse Metals has received a green light from the Greenland Government to commence initial exploration fieldwork at Ivittuut in the country’s south-west, enabling it to get boots on the ground next month at what was once the world’s only commercial source of cryolite.
Examination of the former open-pit mine’s ground conditions and geological features will give Eclipse a start on its plans to compile a JORC-compliant resource and ultimately move into a project feasibility study for Ivittuut.
The company’s approved programme of work at Ivittuut will include an overall field assessment and sampling of the existing mullock heaps and of geological bulk intrusions. Management expects the appraisal will pave the way for further testwork to facilitate calculation of a JORC resource.
Eclipse’s planned initial program will also include sampling of the nearby Gronnedal-Ika carbonatite prospect to ascertain the extent of its rare earth elements or “REE” mineralisation.
Ivittuut is the world’s largest source of naturally occurring cryolite, an extremely rare sodium aluminium fluoride mineral used exclusively in the extraction of aluminium from bauxite. Cryolite additionally has uses in pesticides and fireworks.
Besides Ivittuut only minor deposits of cryolite have been reported in some areas of Spain, in Colorado, USA, at the Falcon Quarry near Montreal in Canada and in Miask, Russia, but none of these are considered commercial grade.
The Greenland town that bequeathed the mine its name is located near the morosely named Cape Desolation at the very tip of southwestern Greenland on the ruins of a former Norse settlement. Ivittuut’s cryolite deposit was discovered in 1799 and the veins of surrounding silver-bearing lead were mined by the British before silver production became uneconomical. Danish engineers began mining the cryolite itself in 1859 and in 1864 a Danish company was granted a monopoly licence for its extraction.These early mines simply processed the cryolite for its aluminium content and for sale to the Pennsylvania Salt Manufacturing Company that used it to create caustic soda.
The 1884 establishment of the Hall-Heroult Process that was dependent on cryolite dramatically improved the extraction of aluminium from bauxite ore and increased the deposit's strategic importance. The Ivittuut mining operations were a major factor in the American occupation of Greenland during World War II. After World War II, the mining of the cryolite was mined by the Danish to help fund the establishment of today's Air Greenland.
Cryolite was eventually synthesized, reducing the importance of the mine, and production was finally uneconomic and the mine discontinued in 1985. However, Eclipse has access to about 19,000m of historical diamond drill core currently stored in a Greenland government facility.
Cryolite occurs most commonly as a late-stage mineral in granites and pegmatites and in fluorine-rich, topaz-bearing rhyolites and within carbonatite veins. The association of the Ivittuut deposit with the nearby Gronnedal-Ika carbonatite that Eclipse is targeting for REE is therefore significant.
The Ivittuut deposit is a zoned mineralised body emplaced in a nearly cylindrical granite intrusion enveloped by a breccia in contact with Archean granodioritic gneiss. Most remaining fluorite, sphalerite and cryolite mineralisation lies within 40-80m of the bottom of the open pit, under the largely mined-out upper cryolite zone. The mined cryolite deposit originally contained 3.8 million tonnes of ore at a grade of 58 per cent.
Greenland Government approval for its planned initial exploration gives Eclipse a licence to advance its work at Ivittuut and the market a reason to keep a close eye on a company with its foot on what is the world’s only known marketable source of cryolite.
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By Matt Birney
