Rare Earth Mining and Exploration in North America

Mariano, Anthony N.

doi:10.2113/gselements.8.5.369

Cited by 105 publications

(70 citation statements)

References 15 publications

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“…However, this is not unique. The second largest deposit of rare earths in the U.S. (Bear Lodge alkaline complex, Wyoming) is also ancylitic [67]. Based on the available information on the geology of the Bear Lodge REE carbonatites [13], the similarity of the complexes is both mineralogical and geochemical.…”

Section: Discussionmentioning

confidence: 99%

Ti-Nb Mineralization of Late Carbonatites and Role of Fluids in Its Formation: Petyayan-Vara Rare-Earth Carbonatites (Vuoriyarvi Massif, Russia)

et al. 2018

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This article is devoted to the geology of titanium-rich varieties of the Petyayan-Vara rare-earth dolomitic carbonatites in Vuoriyarvi, Northwest Russia. Analogues of these varieties are present in many carbonatite complexes. The aim of this study was to investigate the behavior of high field strength elements during the late stages of carbonatite formation. We conducted a multilateral study of titanium-and niobium-bearing minerals, including a petrographic study, Raman spectroscopy, microprobe determination of chemical composition, and electron backscatter diffraction. Three TiO 2 -polymorphs (anatase, brookite and rutile) and three pyrochlore group members (hydroxycalcio-, fluorcalcio-, and kenoplumbopyrochlore) were found to coexist in the studied rocks. The formation of these minerals occurred in several stages. First, Nb-poor Ti-oxides were formed in the fluid-permeable zones. The overprinting of this assemblage by residual fluids led to the generation of Nb-rich brookite (the main niobium concentrator in the Petyayan-Vara) and minerals of the pyrochlore group. This process also caused niobium enrichment with of early generations of Ti oxides. Our results indicate abrupt changes in the physicochemical parameters at the late hydro (carbo) thermal stage of the carbonatite formation and high migration capacity of Ti and Nb under these conditions. The metasomatism was accompanied by the separation of these elements.

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Section: Discussionmentioning

confidence: 99%

Ti-Nb Mineralization of Late Carbonatites and Role of Fluids in Its Formation: Petyayan-Vara Rare-Earth Carbonatites (Vuoriyarvi Massif, Russia)

et al. 2018

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“…Weld, Australia [24]; Araxa and Catalao I, Brazil [8,25]; Tomtor, Russia [23]; Mrima Hill, Kenya [26]; Mabouni, Gabon; and several other carbonatite laterites in the Amazon region of Brazil [27]. Carbonate minerals are easily dissolved when carbonatite is subjected to chemical weathering, and Ca and Mg can be removed, leaving behind less mobile elements (e.g., REEs and Sr) [8].…”

Section: Texture Characteristics Of Monazitementioning

confidence: 99%

“…Both of the latter deposits are bastnasite dominated with associated monazite. Traditionally, the most important deposits for monazite extraction are beach sands and river placers, and are often processed as by-products of ilmenite, zircon, and cassiterite mining [27]. They are typically concentrated via initial high-capacity gravity separation steps to take advantage of the high specific gravity of monazite (greater than 5), whereas typical gangue minerals in these deposits have specific gravities less than 3.5 [4].…”

Section: Beneficiation Of Monazitementioning

confidence: 99%

Geochemistry of Monazite within Carbonatite Related REE Deposits

et al. 2017

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Approximately >50% of global rare earth element (REE) resources are hosted by carbonatite related deposits, of which monazite is one of the most important REE minerals. Monazite dominates more than 30 carbonatite-related REE deposits around the world, including currently exploited mineralization at Bayan Obo and Mount Weld. These deposits are widely distributed across all continents, except Antarctica. Though rare, monazite occurs as the primary mineral in carbonatite, and mostly presents as a secondary mineral that has a strong association with apatite. It can partially or completely replace thin or thick overgrowth apatite, depending on the availability of REE. Other mineral phases that usually crystallize together with monazite include barite, fluorite, xenotime, sulfide, and quartz in a carbonate matrix (e.g., dolomite, calcite). This review of monazite geochemistry within carbonatite-related REE deposits aims to provide information regarding the use of monazite as a geochemical indicator to track the formation history of the REE deposits and also supply additional information for the beneficiation of monazite. The chemical compositions of monazite are highly variable, and Ce-monazite is the dominant solid solution in carbonatite related deposits. Most monazite displays steep fractionation from La to Lu, absent of either Eu or Ce anomalies in the chondrite normalized REE plot. The other significant components are huttonite and cheratite. Some rare sulfur-bearing monazite is also identified with an SO 3 content up to 4 wt %. A 147 Sm/ 144 Nd ratio with an average~0.071 for monazite within carbonatite-related ores is similar to that of their host rocks (~0.065), and is the lowest among all types of REE deposits. Sm/Nd variation of monazite from a single complex reflects the differentiation stage of magma, which decreases from early to late. Based on the differences of Nd and Sr abundances, Nd isotopic composition for monazite can be used to track the magma source, whereas Sr isotopic composition records the signatures of the fluid source. Th-(U)-Pb age determination of the secondary monazite records variable thermal or metasomatic disturbances, and careful geochronological interpretation should be brought forward combined with other lines of evidence. ThO 2 is the most difficult contamination in the beneficiation of monazite, luckily, the ThO 2 content of monazite within carbonatite is generally low (<2 wt %).

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“…Most are won from the ion adsorption clays of south China, with minor amounts from the other four of the "big five" REE deposit types: bastnaesite, monazite, xenotime, and apatite ores. These five provide virtually all, more than 95%, of global REE extraction supply [13] [14] [15] [16] [17].…”

Section: Introductionmentioning

confidence: 99%

Remarkably Consistent Rare Earth Element Grades at Round Top Yttrofluorite Deposit

Pingitore¹,

Clague²,

Gorski³

2018

AMPC

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The peraluminous rhyolite that forms Round Top Mountain (approximately 375 m high × nearly 2 km in diameter), near Sierra Blanca, Hudspeth County, west Texas, USA, is enriched in yttrium and heavy rare earth elements (YHREEs), as well as Li, Be, U, Th, Sn, F, Rb, Cs, Nb, and Ta. Texas Mineral Resources Corp. (USA) proposes to release the YHREEs from their unique yttrofluorite host via heap leaching with dilute sulfuric acid. The inexpensive process also releases portions of valuable byproduct Be, Li, and U from accessory minerals amid the insoluble feldspars and quartz that comprise 90% -95% of the surface-exposed rhyolite mountain. The objective of this study is to determine the consistency of mineralization grade, an important consideration in mine planning and preliminary economic analysis. The method is to plot elemental analyses of Y, Dy, Ho, Tm, Yb, Ce, Pr, Nd, Eu, Gd, Tb, U, and Nb from more than 1400 reverse circulation cuttings taken from 64 exploration drill holes against sample depth. The result of inspection of the plots reveals a remarkably homogeneous distribution of minor and trace elements throughout the sampled portion of the massive, 1.6-billion-tonne laccolith. The plots drive the conclusion that Round Top mine feedstock should remain constant for the life of the mine (multiple decades). Thus mining mechanics could be optimized at the start of operations and not require expensive later changes. The physical and chemical design of the heap leach and recovery and purification of target elements from pregnant leach solution also could be perfected during early development.

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Rare Earth Mining and Exploration in North America

Cited by 105 publications

References 15 publications

Ti-Nb Mineralization of Late Carbonatites and Role of Fluids in Its Formation: Petyayan-Vara Rare-Earth Carbonatites (Vuoriyarvi Massif, Russia)

Ti-Nb Mineralization of Late Carbonatites and Role of Fluids in Its Formation: Petyayan-Vara Rare-Earth Carbonatites (Vuoriyarvi Massif, Russia)

Geochemistry of Monazite within Carbonatite Related REE Deposits

Remarkably Consistent Rare Earth Element Grades at Round Top Yttrofluorite Deposit

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