A Literature review on the Geology and Mineral Industry of Sierra Leone

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Geologic Country Report with Emphasis on Diamonds, Gold, and Titanium (July 2011)
The Republic of Sierra Leone is located on the West Coast of Africa, between latitudes 7 and 10 north and longitudes 10.5 and 13 west.
The mining sector is a significant contributor to Sierra Leone’s economy; it accounted for about 90 % of export revenues, mainly from diamond exports, and 20 % of the gross domestic product (GDP). Sierra Leone was the world’s 10th ranked producer of diamond by volume in 2009 and the world’s third ranked producer of rutile. (more…)

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Geochemical composition of sedimentary rocks and imprint of hydrothermal fluid flow at the Variscan front – an example from the RWTH-1 well (Germany)

The mineralogical and chemical characteristics of Palaeozoic rocks in the northern Eifel Mountains provide information on the sedimentary provenance in the NW Rhenohercynian Basin and on the mineralogical and hydrothermal control of trace element abundance. Elements mainly bound to illite (i.e. V, Ni, Rb, Sr, Cu, Ba) can be distinguished from elements predominantly controlled by chromite (Cr) and zircon (Zr). Lower Devonian and Upper Carboniferous units have similar (more…)

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Minerals of the pyrochlore group as niobium-ore

In comparison to other commodities, e.g. gold, niobium-ores are related to a small number of igneous rocks, in particular carbonatites and genetically-related silicate-carbonate rocks.
Within these rocks niobium is segregated principally in oxide minerals such as the pyrochlore-microlite solid solution series (Ca,Na)2(Nb,Ta)2O6(O,OH,F) and niobian perovskite (Ca,Na)(Ti,Nb)O3. At least four other Nb minerals can occur in sufficient quantities to dominate or affect the niobium content of a carbonatite. They include ferrocolumbite FeNb2O6, fersmite (Ca,REE,Na)(Nb,Ta,Ti)2(O,OH,F)6, niocalite Ca4NbSi2O10(O,F), and wöhlerite NaCa2(Zr,Nb)Si2O8(O,OH,F). Pyrochlore is the dominant niobium host and the only mineral (more…)

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Wakefieldite-(La), LaVO4 , a new mineral species from the Glucksstern Mine, Friedrichroda, Thuringia, Germany

Wakefieldite-(La), ideally LaVO4, is a new mineral from the long abandoned Glücksstern Mine, Gottlob hill, Friedrichroda, Thuringia, Germany. The mineral occurs as light pinkish to brown prismatic crystals up to 0.5 mm in length. Wakefieldite-(La) is associated with hausmannite, baryte and gottlobite. The streak is white, the Mohs hardness 4 and the luster adamantine. The crystals are transparent to translucent. Electron microprobe analysis (more…)

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Geochemical composition of sedimentary rocks and imprint of hydrothermal fluid flow at the Variscan front – an example from the RWTH-1 well

The RWTH-1 well within Aachen offers outstanding conditions for the study of Devonian to Carboniferous sedimentary rocks in the NW Rhenohercynian close to the Brabant Massif. The geochemical data obtained from core and cutting samples provide information on the depositional history (Lower Devonian, Siegenian, to Upper Carboniferous, Namurian to Westphalian) of the NW-Rhenohercynian basin and set constraints on the mineralogical and hydrothermal control on trace element abundance in the northern Eifel region (more…)

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