Bastnäsite

Last updated
Bastnäsite, bastnaesite
Bastnaesit Burundi.jpg
Bastnäsite from Gakara Burundi
General
Category Carbonate mineral
Formula
(repeating unit)		(La, Ce, Y)CO3F
IMA symbol Bsn [1]
Strunz classification 5.BD.20a
Crystal system Hexagonal
Crystal class Ditrigonal dipyramidal (6m2)
H-M symbol: (6 m2)
Space group P62c
Unit cell a = 7.118(1)  Å,
c = 9.762(1) Å; Z = 6
(bastnäsite-(Ce))
Identification
ColorHoney-yellow, reddish brown
Crystal habit Tabular to equant striated crystals, deep grooves may resemble thin plates stack, oriented overgrowths, also granular, massive
Twinning Dauphine law, Brazil law and Japan law
Cleavage Imperfect to indistinct on {1010}, parting on {0001}
Fracture Uneven
Tenacity Brittle
Mohs scale hardness4–5
Luster Vitreous, greasy, pearly on basal partings
Streak White
Diaphaneity Transparent to translucent
Specific gravity 4.95–5.0
Optical propertiesUniaxial (+)
Refractive index nω = 1.717–1.722
nε = 1.818–1.823
Birefringence δ = 0.101 max.
Pleochroism Faint, E > O, colorless to pale yellow or orange
Other characteristicsStrongly piezoelectric; dark red cathodoluminescence, Radioactive.svg Radioactive if uranium and/or thorium-rich
References [2] [3] [4]

The mineral bastnäsite (or bastnaesite) is one of a family of three carbonate-fluoride minerals, which includes bastnäsite-(Ce) with a formula of (Ce, La)CO3F, bastnäsite-(La) with a formula of (La, Ce)CO3F, and bastnäsite-(Y) with a formula of (Y, Ce)CO3F. Some of the bastnäsites contain OH− instead of F− and receive the name of hydroxylbastnasite. Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium and other rare-earth elements.

Contents

Bastnäsite was first described by the Swedish chemist Wilhelm Hisinger in 1838. It is named for the Bastnäs mine near Riddarhyttan, Västmanland, Sweden. [3] Bastnäsite also occurs as very high-quality specimens at the Zagi Mountains, Pakistan. Bastnäsite occurs in alkali granite and syenite and in associated pegmatites. It also occurs in carbonatites and in associated fenites and other metasomatites. [2] [5]

Composition

Bastnasite crystal from the Manitou District, El Paso County, Colorado, USA (size: 4.3x3.8x3.3 cm) Bastnasite-155010.jpg
Bastnäsite crystal from the Manitou District, El Paso County, Colorado, USA (size: 4.3×3.8×3.3 cm)

Bastnäsite has cerium, lanthanum and yttrium in its generalized formula but officially the mineral is divided into three minerals based on the predominant rare-earth element. [6] There is bastnäsite-(Ce) with a more accurate formula of (Ce, La)CO3F. There is also bastnäsite-(La) with a formula of (La, Ce)CO3F. And finally there is bastnäsite-(Y) with a formula of (Y, Ce)CO3F. There is little difference in the three in terms of physical properties and most bastnäsite is bastnäsite-(Ce). Cerium in most natural bastnäsites usually dominates the others. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium, an important industrial metal.

Crystal structure of bastnasite-(Ce). Color code: carbon, C, blue-gray; fluorine, F, green; cerium, Ce, white; oxygen, O, red. Bastnaesite crystal structure.png
Crystal structure of bastnäsite-(Ce). Color code: carbon, C, blue-gray; fluorine, F, green; cerium, Ce, white; oxygen, O, red.

Bastnäsite is closely related to the mineral series parisite. [7] The two are both rare-earth fluorocarbonates, but parisite's formula of Ca(Ce, La, Nd)2(CO3)3F2 contains calcium (and a small amount of neodymium) and a different ratio of constituent ions. Parisite could be viewed as a formula unit of calcite (CaCO3) added to two formula units of bastnäsite. In fact, the two have been shown to alter back and forth with the addition or loss of CaCO3 in natural environments.[ citation needed ]

Bastnäsite forms a series with the minerals hydroxylbastnäsite-(Ce) [(Ce,La)CO3(OH,F)] and hydroxylbastnäsite-(Nd). [8] The three are members of a substitution series that involves the possible substitution of fluoride (F−) ions with hydroxyl (OH−) ions.

Name

Bastnasite crystal, Zagi Mountain, Federally Administered Tribal Areas, Pakistan. Size: 1.5x1.5x0.3 cm. Bastnasite-(Ce)-177535.jpg
Bastnäsite crystal, Zagi Mountain, Federally Administered Tribal Areas, Pakistan. Size: 1.5×1.5×0.3 cm.

Bastnäsite gets its name from its type locality, the Bastnäs Mine, Riddarhyttan, Västmanland, Sweden. [9] Ore from the Bastnäs Mine led to the discovery of several new minerals and chemical elements by Swedish scientists such as Jöns Jakob Berzelius, Wilhelm Hisinger and Carl Gustav Mosander. Among these are the chemical elements cerium, which was described by Hisinger in 1803, and lanthanum in 1839. Hisinger, who was also the owner of the Bastnäs mine, chose to name one of the new minerals bastnäsit when it was first described by him in 1838. [10]

Occurrence

Although a scarce mineral and never in great concentrations, it is one of the more common rare-earth carbonates. Bastnäsite has been found in karst bauxite deposits in Hungary, Greece and the Balkans region. Also found in carbonatites, a rare carbonate igneous intrusive rock, at the Fen Complex, Norway; Bayan Obo, Mongolia; Kangankunde, Malawi; Kizilcaoren, Turkey and the Mountain Pass rare earth mine in California, US. At Mountain Pass, bastnäsite is the leading ore mineral. Some bastnäsite has been found in the unusual granites of the Langesundsfjord area, Norway; Kola Peninsula, Russia; Mont Saint-Hilaire mines, [11] Ontario, and Thor Lake deposits, Northwest Territories, Canada. Hydrothermal sources have also been reported.

The formation of hydroxylbastnasite (NdCO3OH) can also occur via the crystallization of a rare-earth bearing amorphous precursor. With increasing temperature, the habit of NdCO3OH crystals changes progressively to more complex spherulitic or dendritic morphologies. The development of these crystal morphologies has been suggested [12] to be controlled by the level at which supersaturation is reached in the aqueous solution during the breakdown of the amorphous precursor. At higher temperature (e.g., 220 °C) and after rapid heating (e.g. < 1 h) the amorphous precursor breaks down rapidly and the fast supersaturation promotes spherulitic growth. At a lower temperature (e.g., 165 °C) and slow heating (100 min) the supersaturation levels are approached more slowly than required for spherulitic growth, and thus more regular triangular pyramidal shapes form.

Mining history

In 1949, the huge carbonatite-hosted bastnäsite deposit was discovered at Mountain Pass, San Bernardino County, California. This discovery alerted geologists to the existence of a whole new class of rare earth deposit: the rare earth containing carbonatite. Other examples were soon recognized, particularly in Africa and China. The exploitation of this deposit began in the mid-1960s after it had been purchased by Molycorp (Molybdenum Corporation of America). The lanthanide composition of the ore included 0.1% europium oxide, which was needed by the color television industry, to provide the red phosphor, to maximize picture brightness. The composition of the lanthanides was about 49% cerium, 33% lanthanum, 12% neodymium, and 5% praseodymium, with some samarium and gadolinium, or distinctly more lanthanum and less neodymium and heavies as compared to commercial monazite. The europium content was at least double that of a typical monazite. Mountain Pass bastnäsite was the world's major source of lanthanides from the 1960s to the 1980s. Thereafter, China became an increasingly important rare earth supply. Chinese deposits of bastnäsite include several in Sichuan Province, and the massive deposit at Bayan Obo, Inner Mongolia, which had been discovered early in the 20th century, but not exploited until much later. Bayan Obo is currently (2008) providing the majority of the world's lanthanides. Bayan Obo bastnäsite occurs in association with monazite (plus enough magnetite to sustain one of the largest steel mills in China), and unlike carbonatite bastnäsites, is relatively closer to monazite lanthanide compositions, with the exception of its generous 0.2% content of europium.[ citation needed ]

Ore technology

At Mountain Pass, bastnäsite ore was finely ground, and subjected to flotation to separate the bulk of the bastnäsite from the accompanying barite, calcite, and dolomite. Marketable products include each of the major intermediates of the ore dressing process: flotation concentrate, acid-washed flotation concentrate, calcined acid washed bastnäsite, and finally a cerium concentrate, which was the insoluble residue left after the calcined bastnäsite had been leached with hydrochloric acid. The lanthanides that dissolved as a result of the acid treatment were subjected to solvent extraction, to capture the europium, and purify the other individual components of the ore. A further product included a lanthanide mix, depleted of much of the cerium, and essentially all of samarium and heavier lanthanides. The calcination of bastnäsite had driven off the carbon dioxide content, leaving an oxide-fluoride, in which the cerium content had become oxidized to the less basic quadrivalent state. However, the high temperature of the calcination gave less-reactive oxide, and the use of hydrochloric acid, which can cause reduction of quadrivalent cerium, led to an incomplete separation of cerium and the trivalent lanthanides. By contrast, in China, processing of bastnäsite, after concentration, starts with heating with sulfuric acid.[ citation needed ]

Extraction of rare-earth metals

Process flow diagram for pyrometallurgy extraction of rare-earth metals from bastnasite ore Pyrometallury for rare earth metal extraction from bastnasite ore.jpg
Process flow diagram for pyrometallurgy extraction of rare-earth metals from bastnasite ore

Bastnäsite ore is typically used to produce rare-earth metals. The following steps and process flow diagram detail the rare-earth-metal extraction process from the ore. [13] [14]

  1. After extraction, bastnasite ore is typically used in this process, with an average of 7% REO (rare-earth oxides).
  2. The ore goes through comminution using rod mills, ball mills, or autogenous mills.
  3. Steam is consistently used to condition the ground ore, along with soda ash fluosilicate, and usually Tail Oil C-30. This is done to coat the various types of rare earth metals with either flocculent, collectors, or modifiers for easier separation in the next step.
  4. Flotation using the previous chemicals to separate the gangue from the rare-earth metals.
  5. Concentrate the rare-earth metals and filter out large particles.
  6. Remove excess water by heating to ~100 °C.
  7. Add HCl to solution to reduce pH to < 5. This enables certain REM (rare-earth metals) to become soluble (Ce is an example).
  8. Oxidizing roast further concentrates the solution to approximately 85% REO. This is done at ~100 °C and higher if necessary.
  9. Enables solution to concentrate further and filters out large particles again.
  10. Reduction agents (based on area) are used to remove Ce as Ce carbonate or CeO2, typically.
  11. Solvents are added (solvent type and concentration based on area, availability, and cost) to help separate Eu, Sm, and Gd from La, Nd, and Pr.
  12. Reduction agents (based on area) are used to oxidize Eu, Sm, and Gd.
  13. Eu is precipitated and calcified.
  14. Gd is precipitated as an oxide.
  15. Sm is precipitated as an oxide.
  16. Solvent is recycled into step 11. Additional solvent is added based on concentration and purity.
  17. La separated from Nd, Pr, and SX.
  18. Nd and Pr separated. SX goes on for recovery and recycle.
  19. One way to collect La is adding HNO3, creating La(NO3)3. HNO3 typically added at a very high molarity (1–5 M), depending on La concentration and amount.
  20. Another method is to add HCl to La, creating LaCl3. HCl is added at 1 M to 5 M depending on La concentration.
  21. Solvent from La, Nd, and Pr separation is recycled to step 11.
  22. Nd is precipitated as an oxide product.
  23. Pr is precipitated as an oxide product.

Related Research Articles

<span class="mw-page-title-main">Europium</span> Chemical element, symbol Eu and atomic number 63

Europium is a chemical element; it has symbol Eu and atomic number 63. Europium is a silvery-white metal of the lanthanide series that reacts readily with air to form a dark oxide coating. It is the most chemically reactive, least dense, and softest of the lanthanide elements. It is soft enough to be cut with a knife. Europium was isolated in 1901 and named after the continent of Europe. Europium usually assumes the oxidation state +3, like other members of the lanthanide series, but compounds having oxidation state +2 are also common. All europium compounds with oxidation state +2 are slightly reducing. Europium has no significant biological role and is relatively non-toxic compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds. Europium is one of the rarest of the rare-earth elements on Earth.

<span class="mw-page-title-main">Lanthanum</span> Chemical element, symbol La and atomic number 57

Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. Lanthanum is traditionally counted among the rare earth elements. Like most other rare earth elements, the usual oxidation state is +3, although some compounds are known with an oxidation state of +2. Lanthanum has no biological role in humans but is essential to some bacteria. It is not particularly toxic to humans but does show some antimicrobial activity.

The lanthanide or lanthanoid series of chemical elements comprises at least the 14 metallic chemical elements with atomic numbers 57–70, from lanthanum through ytterbium. In the periodic table, they fill the 4f orbitals. Lutetium is also sometimes considered a lanthanide, despite being a d-block element and a transition metal.

<span class="mw-page-title-main">Neodymium</span> Chemical element, symbol Nd and atomic number 60

Neodymium is a chemical element; it has symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes in air and moisture. When oxidized, neodymium reacts quickly producing pink, purple/blue and yellow compounds in the +2, +3 and +4 oxidation states. It is generally regarded as having one of the most complex spectra of the elements. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach, who also discovered praseodymium. It is present in significant quantities in the minerals monazite and bastnäsite. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Neodymium is fairly common—about as common as cobalt, nickel, or copper and is widely distributed in the Earth's crust. Most of the world's commercial neodymium is mined in China, as is the case with many other rare-earth metals.

<span class="mw-page-title-main">Rare-earth element</span> Any of the fifteen lanthanides plus scandium and yttrium

The rare-earth elements (REE), also called the rare-earth metals or rare earths or, in context, rare-earth oxides, and sometimes the lanthanides, are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals. Compounds containing rare earths have diverse applications in electrical and electronic components, lasers, glass, magnetic materials, and industrial processes.

<span class="mw-page-title-main">Gadolinite</span> Nesosilicate mineral

Gadolinite, sometimes known as ytterbite, is a silicate mineral consisting principally of the silicates of cerium, lanthanum, neodymium, yttrium, beryllium, and iron with the formula (Ce,La,Nd,Y)2FeBe2Si2O10. It is called gadolinite-(Ce) or gadolinite-(Y), depending on the prominent composing element. It may contain 35.5% yttria sub-group rare earths, 2.2% ceria earths, as much as to 11.6% BeO, and traces of thorium. It is found in Sweden, Norway, and the US.

<span class="mw-page-title-main">Mischmetal</span> Pyrophoric rare-earth metal alloy

Mischmetal (from German: Mischmetall – "mixed metal") is an alloy of rare-earth elements. It is also called cerium mischmetal, or rare-earth mischmetal. A typical composition includes approximately 55% cerium, 25% lanthanum, and 15~18% neodymium, with traces of other rare earth metals; it contains 95% lanthanides and 5% iron. Its most common use is in the pyrophoric ferrocerium "flint" ignition device of many lighters and torches, although an alloy of only rare-earth elements would be too soft to give good sparks. For this purpose, it is blended with iron oxide and magnesium oxide to form a harder material known as ferrocerium. In chemical formulae it is commonly abbreviated as Mm, e.g. MmNi5.

<span class="mw-page-title-main">Monazite</span> Mineral containing rare-earth elements

Monazite is a primarily reddish-brown phosphate mineral that contains rare-earth elements. Due to variability in composition, monazite is considered a group of minerals. The most common species of the group is monazite-(Ce), that is, the cerium-dominant member of the group. It occurs usually in small isolated crystals. It has a hardness of 5.0 to 5.5 on the Mohs scale of mineral hardness and is relatively dense, about 4.6 to 5.7 g/cm3. There are five different most common species of monazite, depending on the relative amounts of the rare earth elements in the mineral:

<span class="mw-page-title-main">Praseodymium</span> Chemical element, symbol Pr and atomic number 59

Praseodymium is a chemical element; it has symbol Pr and the atomic number 59. It is the third member of the lanthanide series and is considered one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

<span class="mw-page-title-main">Didymium</span> Mixture of praseodymium and neodymium

Didymium is a mixture of the elements praseodymium and neodymium. It is used in safety glasses for glassblowing and blacksmithing, especially with a gas (propane)-powered forge, where it provides a filter that selectively blocks the yellowish light at 589 nm emitted by the hot sodium in the glass without having a detrimental effect on general vision, unlike dark welder's glasses. The usefulness of didymium glass for eye protection of this sort was discovered by Sir William Crookes.

Neodymium(III) chloride or neodymium trichloride is a chemical compound of neodymium and chlorine with the formula NdCl3. This anhydrous compound is a mauve-colored solid that rapidly absorbs water on exposure to air to form a purple-colored hexahydrate, NdCl3·6H2O. Neodymium(III) chloride is produced from minerals monazite and bastnäsite using a complex multistage extraction process. The chloride has several important applications as an intermediate chemical for production of neodymium metal and neodymium-based lasers and optical fibers. Other applications include a catalyst in organic synthesis and in decomposition of waste water contamination, corrosion protection of aluminium and its alloys, and fluorescent labeling of organic molecules (DNA).

<span class="mw-page-title-main">Parisite-(Ce)</span>

Parisite is a rare mineral consisting of cerium, lanthanum and calcium fluoro-carbonate, Ca(Ce,La)2(CO3)3F2. Parisite is mostly parisite-(Ce), but when neodymium is present in the structure the mineral becomes parisite-(Nd).

<span class="mw-page-title-main">Rare-earth mineral</span> Mineral containing one or more rare-earth elements as major constituents

A rare-earth mineral contains one or more rare-earth elements as major metal constituents. Rare-earth minerals are usually found in association with alkaline to peralkaline igneous complexes in pegmatites. This would be associated with alkaline magmas or with carbonatite intrusives. Perovskite mineral phases are common hosts to rare-earth elements within the alkaline complexes. Mantle-derived carbonate melts are also carriers of the rare earths. Hydrothermal deposits associated with alkaline magmatism contain a variety of rare-earth minerals.

<span class="mw-page-title-main">Bastnäs</span>

Bastnäs is an ore field near Riddarhyttan, Västmanland, Sweden. The mines in Bastnäs were earliest mentioned in 1692. Iron, copper and rare-earth elements were extracted from the mines and 4,500 tons of cerium was produced between 1875 and 1888.

<span class="mw-page-title-main">Yttrium</span> Chemical element, symbol Y and atomic number 39

Yttrium is a chemical element; it has symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals and is never found in nature as a free element. 89Y is the only stable isotope and the only isotope found in the Earth's crust.

<span class="mw-page-title-main">Cerium</span> Chemical element, symbol Ce and atomic number 58

Cerium is a chemical element; it has symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is also considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure.

The Mountain Pass Rare Earth Mine and Processing Facility, owned by MP Materials, is an open-pit mine of rare-earth elements on the south flank of the Clark Mountain Range in California, 53 miles (85 km) southwest of Las Vegas, Nevada. In 2020 the mine supplied 15.8% of the world's rare-earth production. It is the only rare-earth mining and processing facility in the United States.

<span class="mw-page-title-main">Indian Rare Earths</span> Government-owned corporation

IREL (India) Limited is an Indian Public Sector Undertaking based in Mumbai, Maharashtra. It has a specialization in mining and refining of rare earth metals.

Florencite-(Sm) is a very rare mineral of the plumbogummite group (alunite supergroup) with simplified formula SmAl3(PO4)2(OH)6. Samarium in florencite-(Sm) is substituted by other rare earth elements, mostly neodymium. It does not form separate crystals, but is found as zones in florencite-(Ce), which is cerium-dominant member of the plumbogummite group. Florencite-(Sm) is also a samarium-analogue of florencite-(La) (lanthanum-dominant) and waylandite (bismuth-dominant), both being aluminium-rich minerals.

<span class="mw-page-title-main">Fluorocarbonate</span> Class of chemical compounds

A carbonate fluoride, fluoride carbonate, fluorocarbonate or fluocarbonate is a double salt containing both carbonate and fluoride. The salts are usually insoluble in water, and can have more than one kind of metal cation to make more complex compounds. Rare-earth fluorocarbonates are particularly important as ore minerals for the light rare-earth elements lanthanum, cerium and neodymium. Bastnäsite is the most important source of these elements. Other artificial compounds are under investigation as non-linear optical materials and for transparency in the ultraviolet, with effects over a dozen times greater than Potassium dideuterium phosphate.

References

  1. ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. 1 2 Bastnäsite. Handbook of mineralogy.
  3. 1 2 Bastnasite-(Ce). Webmineral.
  4. ↑ Bastnasite. Mindat. Retrieved on 2011-10-14.
  5. ↑ Bastnasite Archived November 13, 2007, at the Wayback Machine . Mineral Galleries. Retrieved on 2011-10-14.
  6. ↑ Beatty, Richard; 2007; Th℮ Lanthanides; Publish℮d by Marshall Cavendish.
  7. ↑ Gupta, C. K. (2004) Extractive metallurgy of rare earths, CRC Press ISBN   0-415-33340-7.
  8. ↑ Robert E. Krebs (2006). The history and use of our earth's chemical elements: a reference guide. Greenwood Publishing Group. ISBN   978-0-313-33438-2 . Retrieved 14 October 2011.
  9. ↑ Adrian P. Jones; Frances Wall; C. Terry Williams (1996). Rare earth minerals: chemistry, origin and ore deposits. Springer. ISBN   978-0-412-61030-1 . Retrieved 14 October 2011.
  10. ↑ Sahlström, Fredrik; Jonsson, Erik; Högdahl, Karin; Troll, Valentin R.; Harris, Chris; Jolis, Ester M.; Weis, Franz (2019-10-23). "Interaction between high-temperature magmatic fluids and limestone explains 'Bastnäs-type' REE deposits in central Sweden". Scientific Reports. 9 (1): 15203. Bibcode:2019NatSR...915203S. doi: 10.1038/s41598-019-49321-8 . ISSN   2045-2322. PMC   6811582 . PMID   31645579.
  11. ↑ Fieldtrip guidebook mcgill.ca
  12. ↑ Vallina, B., Rodriguez-Blanco, J. D., Blanco, J. A. and Benning, L. G. (2014) The effect of heating on the morphology of crystalline neodymium hydroxycarbonate, NdCO3OH. Mineralogical Magazine, 78, 1391–1397. DOI: 10.1180/minmag.2014.078.6.05.
  13. ↑ Long, Keith R., Bradley S. Van Gosen, Nora K. Foley, and Daniel Cordier. "Scientific Investigations Report 2010--5220". The Principal Rare Earth Elements Deposits of the United States -- A Summary of Domestic Deposits and a Global Perspective. USGS, 2010. Web. 03 Mar. 2014.
  14. ↑ McIllree, Roderick. "Kvanefjeld Project – Major Technical Breakthrough". ASX Announcements. Greenland Minerals and Energy LTD, 23 Feb. 2012. Web. 03 Mar. 2014.

Bibliography

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