Search

Investigations of Sb-based chalcogenides, stephanite Ag5SbS 4 and bournonite CuPbSbS 3, have been performed by 121,123Sb nuclear quadrupole resonance (NQR). In stephanite a phase transition at 140 K and internal diffusion motions with an activation energy of 0.29 eV have been experimentally detected. The analysis of experimental results for bournonite revealed two crystal-chemical positions of Sb in the unit cell with distinct local symmetry. The NQR frequencies ν and line-widths Δν data indicate that Sb(A)S3 complex has almost axial symmetry, but Sb(B)S 3 complex is substantially distorted.

The deposit, mined from 1961 to 1992, includes four stages of mineralisation: Fe-As-Au sulphides, mainly arsenopyrite and pyrite; Pb-Zn-Cu-Ag-Au sulphides and gold, commonly filling cracks in arsenopyrite and pyrite; Ag-Pb-Cu-Sb sulphosalts such as tetrahedrite, boulangerite, bournonite, pyrargyrite and owyheeite; and calcite with less frequent gypsum. Gold, found in the first three associations, is economically the deposit's most important component. It may have been deposited initially as invisible gold and later remobilised and redeposited with the second-stage sulphides. The deposit has the typical features of some great mesothermal gold deposits in shear zones around the world., The deposit, mined from 1961 to 1992, includes four stages of mineralisation: Fe-As-Au sulphides, mainly arsenopyrite and pyrite; Pb-Zn-Cu-Ag-Au sulphides and gold, commonly filling cracks in arsenopyrite and pyrite; Ag-Pb-Cu-Sb sulphosalts such as tetrahedrite, boulangerite, bournonite, pyrargyrite and owyheeite; and calcite with less frequent gypsum. Gold, found in the first three associations, is economically the deposit's most important component. It may have been deposited initially as invisible gold and later remobilised and redeposited with the second-stage sulphides. The deposit has the typical features of some great mesothermal gold deposits in shear zones around the world.

Meneghinite, boulangerite, freibergite, bournonite and tetrahedrite were identified in hydrothermal veins of the Slovakian quartz-sulphide deposit, occurring in small amounts in association with galena, quartz, sphalerite, pyrite, chalcopyrite and marcasite. The freibergite contained up to 29.5 wt% Ag and 3-4 wt% Fe. Contents of Ag and Zn in tetrahedrite varied from 1.57 to 5.65 wt% and from 4.87 to 7.02 wt% respectively., Meneghinite, boulangerite, freibergite, bournonite and tetrahedrite were identified in hydrothermal veins of the Slovakian quartz-sulphide deposit, occurring in small amounts in association with galena, quartz, sphalerite, pyrite, chalcopyrite and marcasite. The freibergite contained up to 29.5 wt% Ag and 3-4 wt% Fe. Contents of Ag and Zn in tetrahedrite varied from 1.57 to 5.65 wt% and from 4.87 to 7.02 wt% respectively.

Mineralogical characteristics of sulphide ores from the copper-gold deposit have proved to be polymetallic, containing Sn, V, Bi and Te. Both acid-type disseminated and adularia-quartz-type vein Au mineralisation have been recognised within a distance of 500 m. Nine ore types, eight with characteristic assemblages of a range of Cu-Bi, Cu-Sn, Cu-Sn-V, Cu-Te and other sulphide minerals have been distinguished. The gold contents of chalcedonic quartz veinlets in the silicified zone around the deposit range from 1 to 39 g/t, whereas gold mineralisation associated with the sulphide ores seems insignificant. High-Te tetrahedrite in both chalcedonic vein quartz and polymetallic sulphides suggest that the Au mineralisation in the former can be attributed to a hydrothermal system marginal to the polymetallic mineralisation., Mineralogical characteristics of sulphide ores from the copper-gold deposit have proved to be polymetallic, containing Sn, V, Bi and Te. Both acid-type disseminated and adularia-quartz-type vein Au mineralisation have been recognised within a distance of 500 m. Nine ore types, eight with characteristic assemblages of a range of Cu-Bi, Cu-Sn, Cu-Sn-V, Cu-Te and other sulphide minerals have been distinguished. The gold contents of chalcedonic quartz veinlets in the silicified zone around the deposit range from 1 to 39 g/t, whereas gold mineralisation associated with the sulphide ores seems insignificant. High-Te tetrahedrite in both chalcedonic vein quartz and polymetallic sulphides suggest that the Au mineralisation in the former can be attributed to a hydrothermal system marginal to the polymetallic mineralisation.

The mineralisation at Valle Inferna, in Italy, was already being mined in 1368 and represents a minor example of the mid-Triassic Alpine lead-zinc ores of the central and eastern Alps. The orebodies are hosted by discontinuous belts of tectonic breccias in which galena and subordinate sphalerite, accompanied by abundant calcite and some dolomite, cement heterometric clasts of dolomite. The substantial presence of minor elements such as Cu, Ag, Hg, Cd, Sb, As, Bi and Ni reveals the polymetallic nature of the ores, including a possible genetic link with complex hydrothermal fluids. There may have been a link between such fluids and a geodynamic event at the time of mid-calc-alkaline magmatism in the eastern Alps., The mineralisation at Valle Inferna, in Italy, was already being mined in 1368 and represents a minor example of the mid-Triassic Alpine lead-zinc ores of the central and eastern Alps. The orebodies are hosted by discontinuous belts of tectonic breccias in which galena and subordinate sphalerite, accompanied by abundant calcite and some dolomite, cement heterometric clasts of dolomite. The substantial presence of minor elements such as Cu, Ag, Hg, Cd, Sb, As, Bi and Ni reveals the polymetallic nature of the ores, including a possible genetic link with complex hydrothermal fluids. There may have been a link between such fluids and a geodynamic event at the time of mid-calc-alkaline magmatism in the eastern Alps.

Two small occurrences of Sb-Cu ores in the vicinity of the Magurka deposit, Slovakia, are hosted by granitoid rocks and phyllites of the Nizke Tatry crystalline complex and are paragenetically similar to other deposits in the area. The oldest pyrite (I) at Risianka is accompanied by arsenopyrite and gold with high fineness. Younger pyrite (II) occurs with stibnite and sulphosalts, carbonates, chalcopyrite and pyrite III. Bournonite, tetrahedrite and chalcostibite in quartz and carbonate are thought to represent yet another mineralisation. The ores at Male Zelezne display similar mineralogical relations, with molybdenite, the oldest phase, found in leucocratic granites or silicified veins. The quartz-carbonate veins contain stibnite, sulphosalts, sphalerite, galena and bournonite; pyrite is seen as veinlets in the host rocks or in the Sb-Pb veins, where it is replaced by sulphosalts. The youngest pyrite forms minute euhedral crystals in sphalerite and sulphosalts., Two small occurrences of Sb-Cu ores in the vicinity of the Magurka deposit, Slovakia, are hosted by granitoid rocks and phyllites of the Nizke Tatry crystalline complex and are paragenetically similar to other deposits in the area. The oldest pyrite (I) at Risianka is accompanied by arsenopyrite and gold with high fineness. Younger pyrite (II) occurs with stibnite and sulphosalts, carbonates, chalcopyrite and pyrite III. Bournonite, tetrahedrite and chalcostibite in quartz and carbonate are thought to represent yet another mineralisation. The ores at Male Zelezne display similar mineralogical relations, with molybdenite, the oldest phase, found in leucocratic granites or silicified veins. The quartz-carbonate veins contain stibnite, sulphosalts, sphalerite, galena and bournonite; pyrite is seen as veinlets in the host rocks or in the Sb-Pb veins, where it is replaced by sulphosalts. The youngest pyrite forms minute euhedral crystals in sphalerite and sulphosalts.

Mineralisation at the Maria-Margita base metal deposit in Slovakia forms lenses up to 30 cm in size and is located in two parallel zones hosted by Upper Carboniferous limestones. The main ore minerals are sphalerite, galena, pyrite and chalcopyrite, which are associated with bournonite, tetrahedrite and meneghinite. The compositions of bournonite, galena, chalcopyrite and pyrite are close to the theoretical compositions for these minerals. The Fe and Zn contents in tetrahedrite are in the range 0.30%-3.57 wt% and 3.90-7.50 wt%, respectively. Tetrahedrite sometimes also contains small amounts of Ag up to 1.26 wt%, Hg up to 0.34 wt% and Bi up to 0.26 wt%., Mineralisation at the Maria-Margita base metal deposit in Slovakia forms lenses up to 30 cm in size and is located in two parallel zones hosted by Upper Carboniferous limestones. The main ore minerals are sphalerite, galena, pyrite and chalcopyrite, which are associated with bournonite, tetrahedrite and meneghinite. The compositions of bournonite, galena, chalcopyrite and pyrite are close to the theoretical compositions for these minerals. The Fe and Zn contents in tetrahedrite are in the range 0.30%-3.57 wt% and 3.90-7.50 wt%, respectively. Tetrahedrite sometimes also contains small amounts of Ag up to 1.26 wt%, Hg up to 0.34 wt% and Bi up to 0.26 wt%.

The Pb-Zn ore deposit Pernek-Pod Babou, hosted by metamorphic rocks of Palaeozoic age belonging to the Limbach Formation, consists of an upper and lower vein whose mineralisation has evolved through four mineralisation events. The mineral composition of the first two stages, quartz-arsenopyrite and Pb-Zn sulphide minerals, is the same in both veins whereas the younger mineralisation stages consist of carbonates, dolomite and calcite in the lower vein and barite in the upper vein. Arsenopyrite has an increased Sb content up to 1.6 wt%, and rarely also Bi up to 0.5 wt%. Sphalerite is the main ore mineral, accompanied by galena, pyrite, tetrahedrite enriched in Ag and Fe, freibergite, bournonite and some boulangerite and stephanite. Quartz is the main gangue mineral. Microthermometric measurements of fluid inclusions suggest that Pb-Zn and carbonate stages were deposited from low salinity fluids (1.98-14.18 wt% NaCl eq.) at a minimum temperature range of 150-250 degrees C., The Pb-Zn ore deposit Pernek-Pod Babou, hosted by metamorphic rocks of Palaeozoic age belonging to the Limbach Formation, consists of an upper and lower vein whose mineralisation has evolved through four mineralisation events. The mineral composition of the first two stages, quartz-arsenopyrite and Pb-Zn sulphide minerals, is the same in both veins whereas the younger mineralisation stages consist of carbonates, dolomite and calcite in the lower vein and barite in the upper vein. Arsenopyrite has an increased Sb content up to 1.6 wt%, and rarely also Bi up to 0.5 wt%. Sphalerite is the main ore mineral, accompanied by galena, pyrite, tetrahedrite enriched in Ag and Fe, freibergite, bournonite and some boulangerite and stephanite. Quartz is the main gangue mineral. Microthermometric measurements of fluid inclusions suggest that Pb-Zn and carbonate stages were deposited from low salinity fluids (1.98-14.18 wt% NaCl eq.) at a minimum temperature range of 150-250 degrees C.

The results of a detailed paragenetic study in the former mining district showed that the hydrothermal mineralisation, one of a large group of small and poorly understood siderite occurrences in the Tatric crystalline basement, was formed in four main stages. The first stage is represented by quartz, pyrite I and arsenopyrite I. The second, predominant carbonate stage is characterised by the presence of two generations of siderite, together with ankerite-dolomite and rare calcite. The third stage is represented by a quartz-sulphidic assemblage consisting of a number of ore minerals, including arsenopyrite II, galena, gersdorffite, chalcopyrite, pyrite II, sphalerite, bournonite (PbCuSbS3), kobellite (Pb5Bi8S17), sulphosalts of a giessenite (Pb9CuBi6Sb1.5S30) homeotypic pair and tetrahedrite; the chemical compositions of kobellite and the giessenite homeotypic pair sulphosalts exhibit high Cu and Fe contents: 2.1-4.2% Cu and 0.5-1.4% Fe for kobellite; 1-2.5% Cu and 0-0.8% Fe for giessenite sulphosalts. The final stage involved only rudimentary development of supergene enrichment. Tables are presented of electron microprobe results for each mineral, the chemical compositions are plotted on graphs and phase diagrams and mineralogical features are illustrated., The results of a detailed paragenetic study in the former mining district showed that the hydrothermal mineralisation, one of a large group of small and poorly understood siderite occurrences in the Tatric crystalline basement, was formed in four main stages. The first stage is represented by quartz, pyrite I and arsenopyrite I. The second, predominant carbonate stage is characterised by the presence of two generations of siderite, together with ankerite-dolomite and rare calcite. The third stage is represented by a quartz-sulphidic assemblage consisting of a number of ore minerals, including arsenopyrite II, galena, gersdorffite, chalcopyrite, pyrite II, sphalerite, bournonite (PbCuSbS3), kobellite (Pb5Bi8S17), sulphosalts of a giessenite (Pb9CuBi6Sb1.5S30) homeotypic pair and tetrahedrite; the chemical compositions of kobellite and the giessenite homeotypic pair sulphosalts exhibit high Cu and Fe contents: 2.1-4.2% Cu and 0.5-1.4% Fe for kobellite; 1-2.5% Cu and 0-0.8% Fe for giessenite sulphosalts. The final stage involved only rudimentary development of supergene enrichment. Tables are presented of electron microprobe results for each mineral, the chemical compositions are plotted on graphs and phase diagrams and mineralogical features are illustrated.

The flotation properties of these minerals are not well known. Advanced x-ray spectrometry was used in the mineralogical analysis and the chemical environments in the pulp at the time of separation were determined. The ferrous mineral gudmundite was depressed in lime- and soda-containing, alkaline environments. The lead-antimony mineral boulangerite floated more readily, and the lime alkaline process environment seems to be the most favourable for depression of this mineral, whose behaviour resembles galena. The copper-lead-antimony mineral bournonite floats very easily and is difficult to separate in a process environment that is designed to float chalcopyrite., The flotation properties of these minerals are not well known. Advanced x-ray spectrometry was used in the mineralogical analysis and the chemical environments in the pulp at the time of separation were determined. The ferrous mineral gudmundite was depressed in lime- and soda-containing, alkaline environments. The lead-antimony mineral boulangerite floated more readily, and the lime alkaline process environment seems to be the most favourable for depression of this mineral, whose behaviour resembles galena. The copper-lead-antimony mineral bournonite floats very easily and is difficult to separate in a process environment that is designed to float chalcopyrite.

Investigations of Sb-based chalcogenides, stephanite Ag5SbS 4 and bournonite CuPbSbS 3, have been performed by 121,123Sb nuclear quadrupole resonance (NQR). In stephanite a phase transition at 140 K and internal diffusion motions with an activation energy of 0.29 eV have been experimentally detected. The analysis of experimental results for bournonite revealed two crystal-chemical positions of Sb in the unit cell with distinct local symmetry. The NQR frequencies ν and line-widths Δν data indicate that Sb(A)S3 complex has almost axial symmetry, but Sb(B)S 3 complex is substantially distorted.