27 research outputs found

    Effects of Sodium Iso-butyl Xanthate Dosage on the Froth Flotation of Bead Milled Middle Group 1-3 PGM Ore Blend

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    An investigation was carried out to determine the effects of collector concentration on the grade and recovery in the flotation of middle group 1-3 Platinum Group Metal (PGM) ore mixture. The ore mixture pulp at a relative density of 1.29 was subjected to “bead milling” test, particle size distribution analysis and the 55% passing 75 µm was froth floated at 180, 200 and 220 g/t dosages of sodium isobutyl xanthate (SIBX) and 30 and 80 g/t of Senfroth and Sendep 30D frother and depressant, respectively. The results obtained indicated the predominance of the <38 µm PGM values in the ore and confirmed the need for tertiary milling for better liberation of the PGMs. The grade of the PGM concentrate obtained when dosing at 200 g/t of sodium isobutyl xanthate was highest at 94 g/t and gave the lowest recovery of 53%. The 180 g/t SIBX dosage resulted in highest PGM recovery of 70% and lowest grade of 84 g/t, while dosing at 220 g/t SIBX gave average PGM grades of 90 g/t and recoveries of 60%. The results obtained thus showed that that an SIBX dosage of 180 g/t SIBX would be appropriate when higher recoveries are targeted, while 200 g/t dosage will yield higher grade

    Effects of Sodium Iso-butyl Xanthate Dosage on The Froth Flotation of Bead Milled Middle Group 1-3 PGM Ore Blend

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    An investigation was carried out to determine the effects of collector concentration on the grade and recovery in the flotation of middle group 1-3 Platinum Group Metal (PGM) ore mixture. The ore mixture pulp at a relative density of 1.29 was subjected to “bead milling”  test, particle size distribution analysis  and the 55% passing 75 µm was froth floated at 180, 200 and 220 g/t dosages of sodium isobutyl xanthate (SIBX) and 30 and 80 g/t of Senfroth and Sendep 30D frother and depressant, respectively. The results obtained indicated the predominance of the 38 µm PGM values in the ore and confirmed the need for tertiary milling for better liberation of the PGMs. The grade of the PGM concentrate obtained when dosing at 200 g/t of sodium isobutyl xanthate was highest at 94 g/t and gave the lowest recovery of 53%. The 180 g/t SIBX dosage resulted in highest PGM recovery of 70% and lowest grade of 84 g/t, while dosing at 220 g/t SIBX gave average PGM grades of 90 g/t  and  recoveries of 60%. The results obtained thus showed that that an SIBX dosage of 180 g/t SIBX would be appropriate when higher recoveries are targeted, while 200 g/t dosage will yield higher grade

    Multiple origins of charnockite in the Mesoproterozoic Natal Belt, Kwazulu-Natal, South Africa

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    Four different varieties of charnockitic rocks, with different modes of formation, from the Mesoproterozoic Natal belt are described and new C isotope data presented. Excellent coastal exposures and in a number of quarries and river sections makes this part of the Natal belt a good location for observing charnockitic field relationships. Whereas there has been much debate on genesis of charnockites and the use of the term charnockite, it is generally recognized that the stabilization of orthopyroxene relative to biotite in granitoid rocks is a function of low aH2O (± high CO2), high temperature, and composition (especially Fe/Fe+Mg). From the Natal belt exposures, it is evident that syn-emplacement, magmatic crystallization of charnockite can arise from mantle-derived differentiated melts that are inherently hot and dry (as in the Oribi Gorge granites and Munster enderbite), as well as from wet granitic melts that have been affected through interaction with dry country rock to produce localized charnockitic marginal facies in plutons (as in the Portobello granite). Two varieties of post-emplacement sub-solidus charnockites are also evident. These include charnockitic aureoles developed in leucocratic, biotite, garnet granite adjacent to cross-cutting enderbitic veins that are attributed to metamorphic-metasomatic processes (as in the Nicholson's Point granite, a part of the Margate Granite Suite), as well as nebulous, patchy charnockitic veins in the Margate Granite that are attributed to anatectic metamorphic processes under low-aH2O fluid conditions during a metamorphic event. These varieties of charnockite show that the required physical conditions of their genesis can be achieved through a number of geological processes, providing some important implications for the classification of charnockites, and for the interpretation of charnockite genesis in areas where poor exposure obscures field relationships

    A new U-PB Zircon age for the Portobello Granite from the Southern part of the Natal Metamorphic belt

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    The Portobello granite, which crops out along the littoral in southern Natal is an S-type, red-coloured, foliated, chlorite-biotite granite that preserves evidence of low-temperature alteration. It intruded the 1091 ± 7 Ma Munster Suite quartz monzonori

    U-Pb SHRIMP ages and tectonic setting of the Munster Suite of the Margate Terrane of the Natal Metamorphic Belt

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    New U-Pb Zircon SHRIMP ages of 1091 ± 7.1 Ma and 1093.1 ± 5.8 Ma have been determined for two discrete phases of the Munster Suite. The Munster Suite is a calc-alkaline mafic to intermediate suite of intrusive igneous rocks that form part of the sout

    The nature of the Grenville-age charnockitic A-type magmatism from the Natal, Namaqua and Maud Belts of southern Africa and western Dronning Maud Land, Antarctica

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    The &acd;1030-1090Ma old, locally charnockitic, intrusions which are exposed from Namaqualand in the west, through Natal, into the Maud Province Antarctica in the east, show A-type, within plate granite characteristics. The major and trace element characteristics from all the intrusions are remarkably similar and consistent and are typical of C-Type charnockites. Two-pyroxene thermometry as well as thermometry utilising calibrations from experimental studies of saturation surfaces using Zr, P and Ti suggest temperatures between &acd;850℃ and &acd;1100℃. Pressure estimates from aureole assemblages suggest depths of emplacement between 30-10km. Available isotopic data suggest magma sources in Natal and Antarctica were juvenile, probably mantle derived whereas those in Namaqualand suggest a significant crustal contribution

    Monitoring ground deformation of cultural heritage sites using UAVs and geodetic techniques: the case study of Choirokoitia, JPI PROTHEGO project

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    Proceedings of SPIE - The International Society for Optical Engineering, 2017, Volume 10428, Article number 104280QThis paper presents the integrated methods using UAVs and geodetic techniques to monitor ground deformation within the Choirokoitia UNESCO World Heritage Site in Cyprus. The Neolithic settlement of Choirokoitia, occupied from the 7th to the 4th millennium B.C., is one of the most important prehistoric sites in the eastern Mediterranean. The study is conducted under the PROTHEGO (PROTection of European Cultural HEritage from GeO-hazards) project, which is a collaborative research project funded in the framework of the Joint Programming Initiative on Cultural Heritage and Global Change (JPICH)-Heritage Plus in 2015-2018 (www.prothego.eu) and through the Cyprus Research Promotion Foundation. PROTHEGO aims to make an innovative contribution towards the analysis of geo-hazards in areas of cultural heritage, and uses novel space technology based on radar interferometry to retrieve information on ground stability and motion in the 400+ UNESCO's World Heritage List monuments and sites of Europe. The field measurements collected at the Choirokoitia site will be later compared with SAR data to verify micro-movements in the area to monitor potential geo-hazards. The site is located on a steep hill, which makes it vulnerable to rock falls and landslides
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