A new occurrence of argentopentlandite and gold from the Au-Ag-rich copper mineralisation in the Paliomylos area, Serbomacedonian massif, Central Macedonia, Greece

The Au-Ag-Cu mineralisation in the Paliomylos area is associated with quartz segregations and pegmatoids in the form of boudinaged bodies. The Au, Ag and Cu contents in the ore bodies reach 6.8 ppm, 765 ppm and 0.80 wt%. The ore minerals consist of pyrite, chalcopyrite, sphalerite, pyrrhotite, galena, bismuthinite, argentopentlandite, gersdorffite, cobaltite, aikinite, hessite, native bismuth and gold. Pentlandite contains significant amounts in Ag (13.15 wt%), Au (1.59 wt%) and PGM, demonstrating a formula of Fe5.37 Ni2.56 Ag1.03 Ir0.03 S8.01. On the basis of geological, textural and chemical data, the mineralisation in the studied area was formed under high temperatures

ENVIRONMENTAL CONTAMINATION BY SUBSTRATA OF ORE MINING DUMPS, THEIR MONITORING AS WELL AS MEASURES OF REDUCTION

The main activity fields of the research group “Applied Geoecology“ at the University of Potsdam are the development and tests of complex monitoring systems for water bodies and soils, together with the development of sustainable additives for vegetation restoration on ore mining dumps with extreme substratum parameters. The dump substrata are translocated by surface waters and by aeolian processes to the surroundings affecting soil processes. A field spectrometer has been engineered, which can detect dam substrata in soils. Moreover, various soil additives were developed, enabling the establishment of vegetation on the extreme dump substrata. For all components there have been realised extensive tests in the framework of greenhouse and field experiments under different climate conditions on three continents, on various substrata and with varying plant species. All experiments were successful, even though no additional irrigation and no mineral fertilizer were allowed to be used, in order to realise the idea of a sustainable greening

MINERALOGICAL AND GEOCHEMICAL CHARACTERIZATION OF THE OLYMPIAS MINE TAILINGS, NE CHALKIDIKI, GREECE

Τα τέλματα της Ολυμπιάδας στην ΒΑ Χαλκιδική, αποτελούν τα κατάλοιπα του εμπλουτισμού του κοιτάσματος Pb-Zn-Au-Ag που εντοπίζεται στα ανθρακικά πετρώματα της Ενότητας Κερδυλίων. Στην παρούσα εργασία, η ορυκτολογική σύσταση των τελμάτων προσδιορίστηκε με τη χρήση περιθλασιμετρίας ακτίνων-Χ (XRD), ηλεκτρονικής μικροσκοπίας σάρωσης (SEM) και οπτικής μικροσκοπίας, ενώ επιπλέον πραγματοποιήθηκαν χημικές αναλύσεις και μετρήσεις pH. Τα αποτελέσματα έδειξαν πως τα τέλματα συνίστανται από σύνδρομα ορυκτά (χαλαζίας, ροδοχρωσίτης, ασβεστίτης, άστριοι, μαρμαρυγίες, καολινίτης και ακτινόλιθος) και σουλφίδια (σιδηροπυρίτης, αρσενοπυρίτης, σφαλερίτης, χαλκοπυρίτης και γαληνίτης), κάτι που δείχνει ότι υπάρχει σχέση με την ορυκτολογική σύσταση της μεταλλοφορίας και των 2089 μητρικών πετρωμάτων. Επίσης, τα τέλματα αποτελούνται από ίχνη οξειδίων Fe (μαγνητίτης, αιματίτης), οξείδια-υδροξείδια Fe (γκαιτίτης) και οξείδια Mn, συχνά εμπλουτισμένα σε Zn και Pb και σε ορισμένες περιπτώσεις Fe, Sb και As. Επιπλέον εντοπίστηκαν δευτερογενή θειικά άλατα (γύψος, ιαροσίτης) και επανθίσματα θειικών αλάτων (σιδηροεξαϋδρίτης, εξαϋδρίτης, αλοτριχίτης). Τα τέλματα της Ολυμπιάδας είναι γενικά μη οξειδωμένα, δημιουργώντας ένα αλκαλικό περιβάλλον. Παρόλα αυτά, λόγω μεταβολών στη σύσταση, σχηματίζονται ξεχωριστές φάσεις περιορισμένης έκτασης, όπως λεπτές στρώσεις και φακοί οξειδωμένου υλικού, οι οποίες δημιουργούν όξινο περιβάλλον. Από την άποψη της περιεκτικότητας σε πολύτιμα μέταλλα, τα τέλματα της Ολυμπιάδας είναι εμπλουτισμένα σε Au (έως 12 g/t) και Ag (έως 20 g/t).The Olympias tailings of NE Chalkidiki, Greece represent the mine wastes produced by the beneficiation of the Pb-Zn-Au-Ag ore deposit, which is hosted within the carbonate rocks of the Kerdylia Unit. In the present study X-Ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, chemical analyses and pH measurements were conducted to determine the tailings mineralogy and chemical composition. The results indicated that they consist of gangue (quartz, rhodochrosite, calcite, dolomite, feldspars, micas, kaolinite and actinolite) and sulfide minerals (pyrite, arsenopyrite, sphalerite, chalcopyrite and galena), reflecting the source ore and its host rock composition, accompanied by traces of Fe-oxides (magnetite, hematite), Fe oxyhydroxides (goethite) and Mn-oxides, often enriched in Zn and Pb and in some cases Fe, Sb and As. Secondary sulfates (gypsum, jarosite) and surface efflorescent salts (ferrohexahydrite, hexahydrite, halotrichite) have also been recognized. The Olympias tailings are generally unoxidized, generating an alkaline environment. However, variations in composition result in the formation of restricted separate phases, such as thin layers and lenses of oxidized material that generates an acidic environment. In terms of precious metals content, the Olympias tailings are enriched in Au (up to 12 g/t) and Ag (up to 20 g/t)

Discovery of ancient gold mining on Thasos (Greece)

Near Kinyra, at the eastern coast of Thasos several ancient galleries were found during the 1979 field- season. The galleries extend up to 100 m into the ridge of Klisidi. They contain numerous traces of ancient mining activity. Mineralogical and chemical studies on limonitic ore samples reveal that gold is the only metal in these galleries which was worth mining in antiquity. The galleries very likely belong to the ancient gold mines which Herodotus described in this area and which, so far, had not been re-located.Près de Kinyra, sur la côte orientale de Thasos plusieurs anciennes galeries furent découvertes pendant la campagne de terrain 1979. Les galeries s'étendent jusqu'à 100 m dans la crête ded Klisidi. Elles contiennent de nombreuses traces d'anciennes activités minières. Les études minéralogiques et chimiques sur des échantillons de minerais limonitiques montrent que l'or était le seul métal qui valait la peine d'être exploité dans l'antiquité dans ces galleries. Celles-ci appartiennent très probablement aux anciennes mines d'or qui ont été décrites par Hérodote dans cette région, et qui jusqu'ici n'avaient pas été localisées.Wagner G.A., Pernicka E., Gentner Wolfgang, Vavelidis M. Discovery of ancient gold mining on Thasos (Greece). In: Revue d'Archéométrie, n°1, 1981. Actes du XXe symposium international d'archéométrie Paris 26-29 mars 1980 Volume III. pp. 313-320

Is the Palea Kavala Bi-Te-Pb-Sb±Au district, northeastern Greece, an intrusion-related system?

Intrusion-related gold systems are generally characterized by a Au-Bi-Te ± Sn-W metal assemblage genetically linked to the emplacement of granitoids. The Palea Kavala ore system, Greece, consists of ~. 150 minor Fe-Mn (Pb ± Zn ± Ag), Fe-Mn-Au, Fe-As-Au, Fe-Cu-Au, and Bi-Te-Au occurrences that occur primarily in quartz-calcite-sulfide veins (hypogene mineralization), or as supergene bodies, in overlapping zones centered on the ~. 21-22. Ma granodioritic Kavala pluton, which intrudes metamorphic rocks of the Paleozoic Rhodope metamorphic core complex. The pluton consists mostly of granodiorite with lesser amounts of diorite, tonalite and monzodiorite, which was emplaced along the regional E-W trending Kavala-Komotini fault. The recently discovered, ~4km long, E-W trending so-called Kavala vein is a sheeted quartz vein system of Bi-Te-Pb-Sb±Au mineralization that crosscuts the Kavala pluton and the schists and gneisses of the Rhodope Massif. The Kavala vein system is comprised of quartz with lesser amounts of K-feldspar, plagioclase and muscovite. Quartz-sericite-pyrite alteration is pervasive but minor kaolinite is also present. Pyrite (~5% of vein volume) contains inclusions of tetradymite (some gold-bearing), bismuthinite, and cosalite. Sulfur isotope values (n=27) of pyrite from the Kavala and Chalkero veins, as well as pyrite and galena from Garizo Hill Fe-Mn-Pb vein range from -1.9 to 1.0‰ (with one outlier of -4.6‰) and suggest a magmatic sulfur source. Homogenization temperatures (Th) of type I (two-phase aqueous liquid-vapor) and type II (three-phase, H2O-CO2-rich) fluid inclusions that homogenize into the liquid phase in quartz from the Kavala and Chalkero veins range from 216.0° to 420.0°C (n=216) and 255.7° to 414.0°C (n=112), respectively. The Th of type III (two-phase aqueous liquid-vapor), which homogenize into the vapor phase, ranges from 210.4° to 323.4°C (n=28). The salinities of type I and type II inclusions range from 15.9 to 22.6wt.% NaCl equiv. and 5.5 to 11.2wt.% NaCl equiv., respectively. Eutectic temperatures of -58.5° to -44.3°C for type I inclusions suggest the presence of appreciable CaCl2 in addition to NaCl. Clathrate melting temperatures for type II inclusions of ~-56.7°C indicate that CO2 is the major component of the gaseous phase, however up to ~6% CH4 is present in some inclusions. The presence of a zoned metallogenetic district centered on Bi-Te-Pb-Sb±Au mineralization within the Kavala pluton, the presence of both magnetite and ilmenite in the Kavala pluton, and the two high-temperature, high-salinity, immiscible carbonic and aqueous fluids associated with the Kavala and Chalkero veins are consistent with them being part of an intrusion-related gold system that formed along the ilmenite-magnetite buffer. © 2011 Elsevier B.V