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Upgrading valuable mineralization and rejecting magnesium silicates by pre-concentration of mafic ores

Altun N. E., Weatherwax T., Klein B.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 1

203--215

EN

Amenability of mafic ores to pre-concentration was investigated with respect to ore mineraliza-tion characteristics. For the pre-concentration tests seven ores from various nickel-copper operations at Sudbury, Ontario were subjected to dense medium separation. Size assays of metal values, i.e. distribution of nickel and copper with respect to size fractions, were also determined. The ores were assessed in three categories of valuable mineralization as massive pure sulphides, coarse massive sulphide grains and disseminated sulphides. For ores with massive pure sulphides and coarse massive sulphide grains even a size classification based pre-concentration route could be sought since a clear trend of metal enrichment was identified towards finer fractions. Orebodies of similar mineralogy had similar responses to pre-concentration tests. The best results were for those ore bodies with a distinct differentiation between mineralization and gangue, i.e. the ores with massive pure sulphides, where nickel recoveries of 97% and mass rejections of 38-53% were achieved. Similar results were obtained for ores with coarse massive sulphides. For disseminated sulphide mineralogy relatively lower mass rejection was attained with acceptable recoveries of metals. Rejection of magnesium bearing gangue, such as talc, was identified as another benefit of pre-concentration. The extent of magnesium rejection occurred as a function of ore mineralogy. Clear distinction between valuable mineralization and gangue provided preferential magnesium rejection at high levels with no or minor metal losses.

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New survey of lead and zinc ore mineralization in Republic of Kosovo

Kołodziejczyk J., Prsek J., Qela H., Asllani B.

Geology, Geophysics and Environment

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2012

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Vol. 38, no. 3

295--305

EN

Kosovo lead and zinc ore deposits are located in the Trepca Belt which extends for over 80 km. Several ore deposits occur in that belt, with the most important - Stan Terg (Trepca). Stan Terg deposit originating at the contact between volcanic breccias and carbonate rocks. Two different types of mineralization can be distinguished. The older one has origin related to pneumatolitic processes, when skarns were formed. The more recent one was formed by hydrothermal processes and has the largest economic importance. Over 70 minerals have been recognized in the Trepca deposit. Further mineralogical investigations will allow for the identification of other rare minerals.

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Mineralizacja polimetaliczna z kopalni Beiyi w okręgu rud żelaza Shilu na wyspie Hajnan w południowych Chinach

Mikulski S.Z., Bakun-Czubarow N., Xu D., Wang Z.

Biuletyn Państwowego Instytutu Geologicznego

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2012

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nr 452

181--197

PL

W regionie górniczym Shilu posiadającym olbrzymie zasoby rud żelaza typu BIF (Banded Iron Formation), oprócz mineralizacji tlenkami Fe (głównie hematyt), występuje lokalnie w spągu 6 poziomu stratygraficznego grupy Shilu, bogata polimetaliczna mineralizacja siarczkowa Cu–Co. W regionie górniczym Shilu występują słabo zmetamorfizowane skały wulkanoklastyczne i węglanowe zaliczane do mezo- i neoproterozoiku, w które intrudowały różnego wieku granitoidy. Przedmiotem badań mikroskopowych w świetle odbitym i w mikroskopie elektronowym CAMECA SX 100, wyposażonym w przystawkę EDS i WDS, była polimetaliczna mineralizacja kruszcowa z kopalni Beiyi i jej okolic. Mineralizacja kruszcowa, głównie pirotynowo-chalkopirytowa oraz kobaltonośny piryt (do ok. 11% wag. Co), występuje w zmienionych skałach węglanowo-krzemianowych i silnie okwarcowanych skałach diopsydowo-tremolitowych w postaci impregnacji, żyłek i masywnych agregatów ziarnistych. Pirotyn i chalkopiryt zawierają liczne wrostki oraz tworzą przerosty z innymi minerałami (sfaleryt, galena, glaukodot, costibit, kobaltyn, arsenopiryt, ullmannit, siegenit, tytanit, Co-bravoit i kasyteryt). Niewielkie kryształy (10–20 μm średnicy) tworzą minerały Bi (matyldyt i cosalit) i argentyt. W paragenezie z barytem, kalcytem i chlorytem pojawiają się amalgamaty Ag–Hg oraz cynober. Wyniki prac pozwoliły rozpoznać nowe, dotychczas nieopisywane ze złoża minerały. Rezultaty badań wskazują na krystalizację minerałów kruszcowych podczas 4–5 oddzielnych etapów precypitacji kruszców z roztworów hydrotermalnych, w zakresie od temperatur średnich do niskich. Wstępne wyniki oznaczeń wieku izotopowego metodą Re–Os młodszej generacji pirytów (pozbawionych domieszek kobaltu) wskazują na ich precypitację w interwale 240–260 mln lat.

EN

The famous Shilu iron-polymetallic ore mining district located in western Hainan Island, South China, occurs within Meso- and Neoproterozoic low-grade metamorphosed volcanoclastics and carbonates, that belong to the 6th sequence of the Shilu Group. Granitoid intrusions of different ages occur in the surroundings of the mining area. The Shilu deposit is considered to be a structurally reworked as well as hydrothermally altered and enriched ore deposit of a Banded Iron Formation type. The deposit is a very important iron producer from hematite (and minor magnetite) ores. Our work focused on the polymetallic sulfide mineralization that underlies the iron oxide ores. We selected several samples of sulfide ores from the Shilu deposit of the Beiyi mine and its close vicinity. We performed detailed ore microscopic studies as well as electron microprobe analyses using the CAMECA SX 100 equipped with EDS and WDS systems. Pyrrhotite, chalcopyrite and Co-bearing pyrite (up to 11 wt% Co) dominated among ore sulfides in the studied samples. These ore minerals occur in calc-silicate rocks and strongly silicified diopside, tremolite-bearing rocks, either as disseminated grains, sometimes in veinlets, or in aggregates that may form massive ores. Pyrrhotite and chalcopyrite may contain numerous solid inclusions, overgrowths and intergrowths of subordinate sulfides (sphalerite, galena), sulfosalts (glaucodot, costibite, cobaltite, arsenopyrite, ullmannite), sulfospinels (siegenite) and cassiterite that belong to the minerals crystallizing at medium to low temperatures. Among these minerals, siegenite and Co-bravoite dominate. Tiny crystals (10–20 μm in size) of Bi-minerals (matildite, cosalite) and argentite are also present. Moreover, in association with barite, calcite and chlorite, Ag-Hg amalgamate and cinnabar can occur. The results of our study point to the multistage medium- to low-temperature hydrothermal precipitation of ore sulfides during 4–5 separate stages. Preliminary results of Re-Os isotope datings indicate that pyrites of younger generation (lack of significant Co admixture) crystallized during 240–260 Ma.