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Galvanic interaction between sulphide minerals and grinding media has a pronounced impact on grinding (in terms of wear rate of balls and liners, energy consumption, product size and throughput) and flotation (in terms of surface products formed which affect mineral hydrophobicity) performance. The main objective of the current research study is to investigate the influence of electrochemical control on grinding and flotation performance. Laboratory tests were carried out on a representative sample taken from the Miduk copper concentrator plant feed under controlled electrochemical conditions. Laboratory grinding tests with different grinding media indicated that chromium balls not only resulted in the reduced grinding media wear in the mill, but also led to the improved flotation performance.The mass wear rate of steel balls was found to be 1.68 times of high-chromium balls. This is related to more oxidizing and alkaline conditions with higher oxygen concentrations in the presence of high-chromium balls. Addition of lime in the mill caused more oxidizing conditions (increasing the pulp Eh from 55.91 mV to 189.79 mV) with higher oxygen content (increasing the pulp DO from 2.44 ppm to 6.39 ppm) of the pulp which eventually resulted in higher flotation grade and recovery. Maximum copper recovery was observed when xanthate (Z11) and thionocarbamate (X231) collectors were added to the flotation cell, while the highest selectivity was achieved when the both collectors were fed directly into the mill. The more reducing grinding conditions and lower oxygen content of the pulp was related to oxidation of xanthate to dixanthogen when it was added into the mill. [ABSTRACT FROM AUTHOR]

The Sargaz Cu–Zn volcanogenic massive sulfide deposit, in the southern Sanandaj–Sirjan Zone, composed of felsic and mafic volcanoclastic, volcanic rocks, with sandstone, limestone and calcareous tuff and NW-SE trending. The basaltic host rocks with mostly tholeiitic to transitional affinity host the massive sulfide mineralization. The alteration zones related to mineralization system representing the channels of ascending hydrothermal solutions existing within a footwall alteration pipe, with a central siliceous and quartz– sericite core giving rise to zones of quartz–chlorite, chlorite–quartz, and finally chlorite– sericite (stringer envelope zone) on the margins. Pervasive alteration started with the development of chlorite–sericite subsequently overprinted by chlorite, sericite, and finally quartz as hydrothermal activity intensified in the center of the alteration zone. Despite intense alteration of the volcanic rocks, immobile elements (i.e. Ti, Zr) have remained essentially immobile, which allows identification of the precursors and calculation of mass changes. Mass changes calculated for mafic footwall rocks indicating most of the volcanic rocks in the mine area are strongly depleted in Na2O and CaO, and highly enriched in MgO, Si2O and K2O. The Si content is the largest within 5–10 m of the massive sulfide lenses. Intensely silicified footwall basaltic rocks underlie the massive sulfide lens in Sargaz deposit were characterized by white to grey, microcrystalline silica. Mass change analysis of altered footwall basaltic rocks immediately below the massive sulphide zone shows the SiO2 content increases to about 90%. The chloritic and chlorite–sericite alteration zones were enriched in Fe, Mg, with only small amount of K in the chlorite–sericite zone but depleted in Na and Ca most likely due to the alteration of clinopyroxene, plagioclase, and volcanic glass. The change from chloritization to silicification and sericitization must be accompanied by a reduction in pH during silicification and sericitization. Identification of such alteration patterns can be used as an exploration key in other massive sulfide mineral exploration. [ABSTRACT FROM AUTHOR]

The volcanic complex of North Khour located in southern Khorasan province, 90 km northwest of Birjand in the Eastern of Iran. The rocks under study are basaltic andesite, andesite and trachyandesite, latite, dacite to rhyodacite with tuff and breccia as pyroclastic rocks. The volcanic rocks are predominantly calc-alkaline nature with some tholeiitic affinity and porphyry texture. Iron mineralization developed as magnetite, hematite and small amount of goethite with magmatic origin, on the base of field observations. Bornite as the only and the primary Cu ore occurred as a small body. The presence of minor amounts of bornite and pyrite as the sulfide phases as well as the absence of the other Cu primary sulfide ores in the area along with secondary Cu mineralization phases reflect a hydrothermal solution with high oxidation degree which has passed the latest magmatic differentiation and gave rise to form surface Cu ores as chalcocite in supergene zone. The thermobarometry of fluid inclusions studies from Ghar Kaftar and Hoze Sabz, yield temperature range of 178 -324 C for Cu mineralization. Therefore, it seems that Cu mineralization is related to epithermal to mesothermal conditions. [ABSTRACT FROM AUTHOR]

The Gol-e-Gohar anomaly#3 of Sirjan was initially formed by synchronous submarine basaltic volcanism and sedimentary rocks (basalt, shale, carbonates, sandstone, marl, chert-iron hydroxide-oxides) during Neoproterozoic (Ediacaran) and subsequently metamorphosed to greenschist facies during Cimmerian orogeny. The anomly contains 643 million tonnes iron ore with an average grade of 52.70% Fe, 0.76% S and 0.11% P and is enclosed by alternation of quartzite, sericite schist, chlorite schist, talc schist, biotite schist, actinolite schist. Magnetite occurs as massive, banded, cataclastic and disseminated ore and is associated with pyrite, minor chalcopyrite and bornite. Pyrite occurs as, layered, banded, folded and cataclastic and minor within the magnetite crystals. Minor minerals are tourmaline, apatite, zircon and garnet. Geochemical data demonstrate that enrichment of Cu, Pb,Co, Sn, As and Sb in magnetite ore is 2-10 times higher than the crustal abundance. The enrichment of Cu, Mo, Pb, Zn, Cr, Ni, Co, As and Sb in sulfide minerals is 3-67 magnitudes higher than the crustal abundance. The alternation of different schist bands with banded magnetite-pyrite ores, the presence of dropstones and Al-Fe-Mn, V-Ti and V/Ti-Ni/Ti diagrams indicate that the iron mineralization in anomaly#3 is similar to the Ediacaran-type banded iron formation.

The Baharieh copper deposit with an approximately of 1 million tons of copper ore, located in Khorasan Razavi Province, 30 km northeast of Kashmar. On the base of structural view point of Iran, the deposit is situated in Sabzevar zone and Taknar metallogenic area. The mineralization as stratabound nature in an ore-horizon with a length of approximately 200 m and 5 to 10 meters thickness, trending E-W occurs in the middle Eocene andesitic to rhyolitic-tuff. Chalcopyrite and pyrite are the main sulfide minerals, which are accompanied by accessory minerals including bornite, galena, sphalerite, covelline, chalcocite, malachite and hematite. According to the data obtained by electron probe micro analysis (EPMA) the maximum gold amount (0.21 wt%) and the silver content (0.1 wt%) are in the chalcopyrite and the highest silver concentration (0.14 wt%) is in the galena. The average ratio of Co/Ni (2.71) in the pyrite study can be indication of its hydrothermal source. On the base of geo-thermometry data as well as Sb/Bi ratio in the galena and the geochemistry of the sphalerite (high content of Cd with an average value of 0.92 wt% and low Zn/Cd=67.54) the physico-chemical and the thermodynamic conditions of ore-bearing fluid in the Baharieh deposit consistent with an average-temperature hydrothermal-magmatic deposits. The variation ranges of δ34S isotopic in the chalcopyrite and the pyrite samples vary from -7.3 to 0.5 ‰. According to the results obtained from sulfur isotopic data, the origin of primary magma for δ34S values close to zero and its relative depletion was confirmed as a result of performance of reduce processes for negative δ34S values. The overall, the primary fine-grained pyrites in the mineralized host rock are most likely the source of sulfur in the sulfide mineralization of the area under study, which caused the negative δ34S values. [ABSTRACT FROM AUTHOR]

The Gol-e-Gohar anomaly#3 of Sirjan was initially formed by synchronous submarine basaltic volcanism and sedimentary rocks (basalt, shale, dolomite, sandstone, marl, chertiron hydroxide-oxides) during Neoproterozoic (Ediacaran) and subsequently metamorphosed to greenschist facies during Cimmerian orogeny. The anomaly contains 643 million tons iron ore with an average grade of 52.70% Fe, 0.76% S and 0.11% P and is enclosed by alternation of quartzite, sericite schist, chlorite schist, talc schist, biotite schist, actinolite schist. Magnetite occurs as massive, banded, cataclastic and disseminated ore and is associated with pyrite, minor chalcopyrite and bornite. Pyrite as magnetite, occurs as layered, banded, folded and cataclastic within the magnetite crystals. Minor minerals are tourmaline, apatite, zircon and garnet. Geochemical data demonstrate that enrichment of Cu, Pb, Co, Sn, As and Sb in magnetite ore is 2-10 times higher than the crustal abundance. The enrichment of Cu, Mo, Pb, Zn, Cr, Ni, Co, As and Sb in sulfide minerals is 3-67 magnitudes higher than the crustal abundance. The alternation of different schist bands with banded magnetite-pyrite ores, the presence of dropstones and Al-Fe-Mn, V-Ti as well as the V/Ti-Ni/Ti diagrams indicate that the iron mineralization in anomaly#3 is similar to the Ediacaran-type banded iron formation. [ABSTRACT FROM AUTHOR]

The Rangraz copper deposit is located 18 km of north of Saveh, in the central part of the Uromieh-Dokhtar magmatic arc. The host rocks are dominated by volcanics and volcaniclastics of Eocene, which altered and mineralized by intruding the quartz monzodiorite intrusion and andesitic-basaltic dikes. Hydrothermal alterations are propylitic, sericitization, silicification, and the chlorite- clay minerals-quartz assemblage. The principal hypogene ore minerals include pyrite, chalcopyrite, bornite, specular hematite, and magnetite. The essential minerals are plagioclase, K-feldspar, quartz, fine grain biotite and amphibole with granular to porphyritic textures. These rocks with metaluminous and calc-alkaline nature.are chemically, characterized by high CaO (2.61 to 5.81 wt%), and Na2O (6.90 to 7.78 wt%) and low K2O (0.04 to 0.38 wt%), Fe2O3 (2.60 to 4.58 wt%), and MgO (1.22 to 2.81 wt%) contents. These chemical features can be caused by the extensive propylitic alteration in the rocks under study. According to the tectonic setting discrimination diagrams, and trace as well as rare earth elements distribution patterns, depletion of Ti, P and LREE enrichment are the criteria of subduction at active continental margin tectonic. The significant negative Eu anomalies and relative Sr depletion point to the presence of plagioclase as a stable phase at magmatic source. The result of petrogenetic studies represent that crystal fractionation, and magma mixing were the most dominant processes controlling magmatic evolution. [ABSTRACT FROM AUTHOR]