Kimberley Michelle Halpin

Bio: Kimberley Michelle Halpin is an academic researcher. The author has contributed to research in topics: Allanite. The author has an hindex of 1, co-authored 1 publications receiving 11 citations.

Geology and market-dependent significance of rare earth element resources

Abstract: China started to produce rare earth elements (REEs) in the 1980s, and since the mid-1990s, it has become the dominant producer. Rare earth element export quotas first introduced by the Chinese government in the early 2000s were severely reduced in 2010 and 2011. This led to strong government-created disparity between prices within China and the rest of the world. Industrialized countries identified several REEs as strategic metals. Because of rapid price increases of REE outside of China, we have witnessed a world-scale REE exploration rush. The REE resources are concentrated in carbonatite-related deposits, peralkaline igneous rocks, pegmatites, monazite ± apatite veins, ion adsorption clays, placers, and some deep ocean sediments. REE could also be derived as a by-product of phosphate fertilizer production, U processing, mining of Ti-Zr-bearing placers, and exploitation of Olympic Dam subtype iron oxide copper gold (IOCG) deposits. Currently, REEs are produced mostly from carbonatite-related deposits, but ion adsorption clay deposits are an important source of heavy REE (HREE). Small quantities of REE are derived from placer deposits and one peralkaline intrusion-related deposit. The ideal REE development targets would be located in a politically stable jurisdiction with a pro-mining disposition such as Canada and Australia. REE grade, HREE/light REE (LREE) ratio of the mineralization, tonnage, mineralogy, and permissive metallurgy are some of the key technical factors that could be used to screen potential development projects. As REEs are considered strategic metals from economic, national security, and environmental points of view, technical and economic parameters alone are unlikely to be used in REE project development decision-making. Recycling of REE is in its infancy and unless legislated, in the short term, it is not expected to contribute significantly to the supply of REE.

Geochemical Characteristics of Apatite in Heavy REE-rich Deep-Sea Mud from Minami-Torishima Area, Southeastern Japan

Abstract: We have conducted geochemical and mineralogical investigations of the rare earth and yttrium (REY)-rich mud from the Minami-Torishima area in the Pacific in order to clarify the concentration of REY and their host-phase in the mud. X-ray diffraction analysis shows that the mud is mainly composed of phillipsite, fluorapatite, quartz, albite, illite and montmorillonite. Whole-rock CaO, P2O5 and total REY contents of the mud are positively correlated. Relative abundance of apatite is also positively correlated to P2O5 and total REY contents. These correlations suggest that apatite is the main host of the P2O5 and REY in the mud. We make in situ compositional analyses of constituent minerals in the REY mud. The results show that the apatite is abundant in REY (9300–32,000 ppm) and is characterized by a negative Ce anomaly and enrichment in heavy rare-earth elements. This abundance and composition of REY of the mud is similar those of fish debris apatites. In contrast, phillipsite is less abundant in REY (60–170 ppm). Therefore we conclude that the main REY host phase of the mud is apatite.

REE Mineralogy and Resources

Abstract: Recent increase of the demand for rare earth elements (REEs), especially dysprosium and terbium used in the permanent magnet industry is modifying a concept of the REE mineralogy and resources. This is amplified by the REE supply restrictions outside of China. Exploration has been extended worldwide to secure the supply of REEs, especially the heavy ones. In recent years, various attempts are made to produce heavy rare earth elements (HREEs) from unconventional sources, such as peralkaline igneous rocks, which have not been regarded as a REE source. Therefore, this paper reviews the potential sources of REEs, especially HREEs (ion-adsorption types and apatite deposits), which are regarded as the most critical group of elements for the future green technologies.

The Ore Minerals and Major Ore Deposits of the Rare Earths

Abstract: This chapter gives an overview of the major and minor ore minerals of the rare earths, and of the related major ore deposits. As most of the rare earths are mined in China, the impression may arise that ore deposits of these metals occur in few other places on Earth. However, nothing is less true. The extensive overview of the ore deposits of the rare earths in this chapter is especially meant to indicate that deposits occur in quite a variety of countries, and that the apparent dominance of China is economically (and politically) powered.

Hydrothermal evolution in the hoidas lake vein-type ree deposit, saskatchewan, canada: constraints from fluid inclusion microthermometry and evaporate mound analysis

Abstract: The Hoidas Lake rare earth element (REE) deposit, located in northern Saskatchewan, Canada, is a structurally controlled vein-type LREE deposit with allanite-(Ce) and fluorapatite as the main REE carriers. The mineralized veins cut Archean and Paleoproterozoic orthogneisses and supracrustal rocks of the southern Rae Subprovince. The paragenesis includes hyalophane-bearing pegmatite dikes, REE-mineralized allanite-, diopside-, hornblende-, hyalophane-, and titanite-bearing veins, and later breccia veins that contain several stages of apatite. The mineralized veins record hydrothermal alteration with nucleation of monazite and REE-carbonate inclusions in apatite and allanite, respectively. Barren quartz-, carbonate-, and hematite-rich veins represent the final stage of hydrothermal activity. Samples from the hyalophane-bearing pegmatites, apatite breccia veins, and quartz-carbonate veins, used for fluid inclusion petrography and microthermometry, indicate four distinct fluid inclusion assemblages (FIAs): (1) carbonic inclusions showing LCO2 (liquid CO2) + VCO2 (CO2 vapor) phase composition with 20–40 vol.% VCO2 at 0 °C; (2) aqueous inclusions showing L (liquid H2O) + V (H2O vapor) phase composition with 90–100 vol.% V at 20 °C; (3) aqueous inclusions showing L + V + H (halite) phase composition with 15 vol.% V at 20 °C; and (4) aqueous L + V inclusions with 15–20 vol.% V at 20 °C. Type 1 inclusions homogenize to liquid CO2 with Th(CO2) from 3.3 to 30.5 °C. Type 2 V-rich inclusions have high salinities and contain salts other than NaCl. Type 3 L-V-H inclusions have different homogenization behavior in quartz of the hyalophane-bearing pegmatites (L+V+H → L+V → L) compared to quartz-carbonate veins (L+V+H → L+H → L), and Th (total homogenization) values range from 180 to 315 °C with salinities of 30–40 wt.% eq. NaCl. In type 4 inclusions Th ranges from 90 to 290 °C, but for specific samples and FIAs (fluid inclusion assemblages) there is a more limited spread (from 5 to 25 °C). Salinities range from 8 to 24 wt.% eq. NaCl, and the inclusions have variable Na/(Na + Ca). Evaporate mound analysis shows average normalized (to 100%) cation contents of 48% Na, 24% Ca, 6% K, 5% Ba, 4% Mn, 2% Fe, 2% Mg, and 9% Sr for quartz-hosted inclusions in quartz-carbonate veins, and 61% Na, 32% Ca, and 7% K for quartz-hosted inclusions in hyalophane-bearing pegmatite dikes. The thermometric and chemical data suggest that evolution of the Hoidas Lake mineralization involved two fluid types with early entrapment of a carbonic fluid followed by introduction of a mixed Na-Ca-K-(Ba-Mn-Mg-Fe-Sr) aqueous fluid with variable salinities that was responsible for the late alteration of the mineralized veins. Furthermore, the inclusion data provide constraints on entrapment temperature (<310 °C) and also indicate that the pressure was transient (0.5 to 2 kbars) based on the homogenization temperature data for the carbonic (type 1) and aqueous L-V-H (type 3) inclusions.