I.F. Chayka1, S.Yu. Stepanov 2, A.V. Kozlov3, F.D. Sandalov4, R.S. Palamarchuk2, N.I. Baykov1, V.S. Zhdanova5, V.D. Abramova4 1Korzhinskii Institute of Experimental Mineralogy RAS, Chernogolovka, Russia ivanlab211@gmail.com 2Natural science museum of the Ilmeny Reserve, Southern Ural center for mineralogy and geoecology UB RAS, Miass, Russia 3Saint Petersburg Mining University of Empress Catherine II, Saint-Petersburg, Russia 4Institute of geology of ore deposits, petrography, mineralogy and geochemistry RAS, Moscow, Russia 5Zavaritsky Institute of Geology and Geochemistry UB RAS, Ekaterinburg, Russia
Keywords: skarn, Cu-Fe skarn formation, native gold, gabbro, S isotopes, Ural Platinum Belt
Skarn-type Fe and Cu deposits enriched in Au are widespread within the Tagil–Magnitogorsk megazone of the Ural Fold Belt and are primarily associated with felsic to intermediate intrusions. In the Northern Urals, Fe–Cu skarn-type deposits and ore occurrences are found in the exocontacts of gabbroic phases of the polyphase intrusions of the Ural Platinum Belt. These systems are of particular interest as they represent the terminal (hydrothermal–metasomatic) stage in the fractionation of chalcophile and noble metals within magmatic systems of young island arcs. The metasomatic rocks developed in the exocontact zone of the Knyaspa intrusion, investigated in this study, contain ore-grade concentrations of Fe and Cu (0.5–5 wt%) and Au (0.2–14 g/t), and are classified as belonging to the Cu–Fe skarn formation of the Ural belt. The geological, mineralogical, and geochemical characteristics of this occurrence are largely typical of Cu–Au skarn deposits and are genetically linked with the gabbroic phase of the intrusion, rather than with the dioritic one. The metasomatic rocks formed after andesibasalts of the Pavda Formation. The following sequence of their formation has been reconstructed: (1) amphibole–plagioclase or clinopyroxene–plagioclase hornfelses (hornfels phase); (2 epidote-bearing assemblages with clinopyroxene or garnet (pre-ore skarn stage of the hydrothermal-metasomatic phase); (3) clinopyroxene–actinolite–epidote associations with magnetite and Cu sulfides (ore skarn stage of the hydrothermal-metasomatic phase); (4) largely zeolite assemblages (late hydrothermal stage of the hydrothermal-metasomatic phase) and (5) supergene phase. The estimated temperatures for the formation of primary sulfide mineralization range from 300 to 400 °C. Formation of native gold, which has exclusively broad compositional range in terms of Cu and Ag admixtures, took place at lower temperatures (approximately 100–250 °C) and probably continued during supergene phase Based on δ34S values in sulfides and the geochemistry of chalcophile elements in skarns, the ore elements were probably orthomagmatic. However, the mobilization of S and Cu from the volcanogenic massive sulfide deposits of the Shemur Formation through their assimilation by the intrusion cannot be ruled out, as well. Regardless of the source, the redox state of sulfur was significantly shifted toward oxidized species (S⁶⁺ or S⁴⁺), resulting in unusually low δ³⁴S values (–6 to –4‰) in the sulfides of the metasomatic rocks.
The first experimental data on the relationship between the carbon dioxide content in minerals of the lazurite-type minerals (LTM) and its partial pressure in the gas phase and temperature in the range corresponding to the lazurite formation process at deposits in the Southern Baikal region have been obtained. The content of structural CO2 species was determined by IR- Fourier spectroscopy. It depends more on temperature than on the partial pressure of CO2
and is maximum for cubic lazurites at 500 °C (0.05-0.07 formula units, f.u.), decreasing to 0.01-0.03 f.u. both when the temperature decreases (460 °C) and when it increases (560 °C). A positive dependence of CO2 content on O2 fugacity in the system has been noted. LTM with an orthorhombic structure (vladimirivanovite) retains CO2 less effectively, with its content decreasing from the initial (natural) 0.08 to 0.01-0.02 f.u. in the specified temperature range of 460-560 °C. The experiments with exposure at 560
oC and subsequent cooling to 460 or 360 oC show the lack of retrograde CO2 solubility in LTM under saturation from gas phase. According to data on CO2 content, cubic lazurites with incommensurate 3D modulation of the structure could have formed at a temperature of about 500 °C, a partial CO2 pressure of ~1.4-2.2 bar, and fO2 at the level of the magnetite-hematite buffer. The high CO2 contents (0.15-0.3 f.u.) recorded in some LTMs may not be related to the direct absorption of CO2 from the gas (fluid) phase, but are the product of relatively low-temperature (<400 °C) transformations of carbon forms, leading to the association of CO2 and molecular forms of sulphur. This temperature range and the fugacity of volatile compounds corresponding to such forms of sulphur should be considered as possible conditions for the synthesis or modification of materials based on sodalite, nosaean and LTMs, which are promising as carbon dioxide absorbers or indicators.
The Mid-Atlantic Ridge within Iceland differs significantly in structure from other ridges. It consists of several modern rift zones with different kinematics and internal structure. At the same time, there are also several inactive rift zones, separated by block uplifts. This structural diversity is caused by the thermal influence of the Icelandic plume, which manifests itself in conditions of asymmetric spreading. To identify the conditions for the development of Icelandic rift zones and the features of their structure in connection with the cyclic plume activity, a physical modeling was used. The resulting model reflects the structure and development of Icelandic rift zones over the last 21.5 million years. It was shown that the kinematics and internal structure of rift zones are a consequence of the development of multi-scale overlaps of spreading centers. Between them, block uplifts arise, which in the modern topography are expressed as elevated peninsulas, mainly in the northern part of the island. The sizes of block uplifts depend on the distance between overlapping spreading axes. As the distance decreases, large uplifts are replaced by a series of small en-echelon blocks. The formation of this structural ensemble is the result of periodic increase in plume activity and its eastward displacement relative to the boundary of the lithospheric plates, which is caused by spreading asymmetry. There are two cycles of plume activity with different durations. The period of 7–8 million years reflects the complete cycle of formation and development of overlappings, and the period of 2–3 million years determines the evolution of the rift zone structure within the entire structural ensemble.
D.A. Nosov1, D.K. Dronov2, Y.G. Turbin2, I.S. Sizikov1. 1Institute of Automation and Electrometry of the Siberian Branch of the Russian Academy of Sciences, postal Novosibirsk, Russia
2Arctic and Antarctic Research Institute, St:Petersburg, Russia
The article presents the first experimental work with the GABL-PM absolute ballistic laser gravimeter on the pier, in ports and on board the ice-resistant platform (LSP) in the expedition "North Pole-42" (SP-42). During the tests, the parametric adjustment of the gravimeter was carried out in order to adapt the device for its operation on the LSP without using a gyrostabilized platform. The results of the GABL-PM measurements at the berth in St. Petersburg are shown, which are required as a reference for testing the gravimeter on the ship, as well as for linking variations in gravity acceleration measured on board the LSP with the Chekan-AM relative gravimeter to absolute values. The estimation of the RMS error of the GAB-PM measurement on board the LSP at various pitching parameters in the ports of St. Petersburg and Murmansk, as well as in the early days of the start of the drift of the North Pole-42 expedition, is given. Based on the measurement results, it was concluded that a gravimeter without a gyrostabilized platform with reduced accuracy values, on average up to 0.60 mGal, can be used to carry out measurements after freezing the vessel and when following all the points of a specially developed instruction.
S. A. Kondrat’ev
Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Flotation, collector, composition of collectors, chemisorption and physisorption, hydrolysis, dissociation, flotation activation, synergetic effect
Flotation involves two forms of sorption using both a collector or a composition of collectors. Effect of the two forms of sorption of a collector can be assumed as a synergy of two reagents-collectors. In this case, flotation runs under conditions of hydrolysis of the reagent or its dissociation. Selection of a reagent mode means creation of condition for the two forms of sorption on a mineral surface. Activation of flotation by cations of metals, catalytic oxidation of xanthate form a sorption layer represented by the chemically or physically adsorbed reagents or by their derivatives. Each form of sorption plays a part in particle-bubble attachment. The first form of sorption aims at enhancement of hydrophobic properties of a mineral to be recovered, and the second form removes the kinetic constraint in the particle-bubble attachment. The strategy of selecting combinations of collectors to reach their synergetic effect in flotation is developed and proposed. Each collector performs its function in the particle-bubble attachment. Enhancement of hydrophobic properties of a mineral, or increase in the density of adsorption of a reagent at its surface results from the fulfilled condition of either chemisorption or physisorption of a reagent or a composition of reagents. It is shown that the properties of the second form of sorption are determined from the mechanism of work of a physically adsorbed collector.
A. G. Mikhailov1,2, Yu. L. Gurevich3, N. F. Usmanova1,2, M. I. Teremova3, A. E. Zuev4 1Institute of Chemistry and Chemical Technology-Division of the Krasnoyarsk Science Center, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia 2Siberian Federal University, Krasnoyarsk, Russia 3Krasnoyarsk Science Center, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia 4Institute of Chemistry and Chemical Technology-Division of the Krasnoyarsk Science Center, Krasnoyarsk, Russia
Keywords: Copper-nickel ore mill tailings, bio-leaching, native bacteria, autochtonous bacteria, capillary rise, hydrogen peroxide, anaerobic conditions
The authors describe the results of leaching of Cu, Ni, Fe and S from copper-nickel ore mill tailings. The lab-scale testing conditions simulated in-situ capillary rise of solutions to ground surface. The leaching agents were water and water solutions of hydrogen peroxide at concentrations of 0.5, 1.0 and 10.0%. Aiming to activate native microorganisms, some columns were introduced with bacteria extracted immediately from the test mill tailings. In the other columns, in order to increase population of native bacteria directly in rock mass, conditions to stimulate their growth were created. The growth in the number of bacteria was observed in the ore mill tailings. The rates of extraction of iron, copper, nickel and sulfur in liquid phase differ depending on the composition of a leach solution.
N. K. Algebraistova1, E. S. Ananenko1, M. I. Teremova2, I. S. Plotnikov1, I. V. Prokop’ev3 1Siberian Federal University, Krasnoyarsk, Russia 2Krasnoyarsk Science Center, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia 3North-Eastern Federal University, Yakutsk, Russia
Keywords: Sulfide mienrals, arsenopyrite, antimonite, flotation, hydrophobic properties, bacteria Pseudomonas Japonica, biotechnology, selection
The modified surface of sulfide minerals (arsenopyrite and antimonite) after bio-treatment with bacteria Pseudomonas Japonica is studied using electroacoustic spectrometer Dispersion DT-310, scanning electron microscope Tescan Vega II SBH, digital technologies and DSA20 EasyDrop unit. It is found that bio-treatment leads to substantial hydrophilization of the mineral surface, which is confirmed by an increase in the wetting angle by 40-50° and in the work of adhesion by 2 times. It is found that the electrochemical properties of the mineral surface also change, including the sign reversal of the ζ -potential and the increase of the electric conductance by an order of magnitude. The scanning electron microscopy proved adsorption of the bacterial cells at the mineral surface. The proof tests confirmed efficiency of the bio-treatment and show reduction in flotation of sulfides by 15-17% in their joint feed with xanthate. The studies display the promising nature of the micro-biological treatment of sulfides before selective flotation.
A. A. Goryachev1,2, E. S. Latyuk3, A. V. Tsyryat’eva4, A. A. Kompanchenko5, D. V. Makarov1 1Institute of Industrial Ecology Problems of the North, Kola Science Center, Russian Academy of Sciences, Apatity, Russia 2Nanomaterials Research Center, Kola Science Center, Russian Academy of Sciences 3RAM LLC, Moscow, Russia 4Apatit Division, Murmansk Arctic State University, Apatity, Russia 5Geological Institute, Kola Science Center, Russian Academy of Sciences, Apatity, Russia
Keywords: Sand wastes, sulfides, ammonia sulfate, low-temperatureroasting, water leaching, pregnant solution, nonferrous metals
The research focuses on processing of copper-nickel alluvial sand wastes at the Verkhnee deposit, Norilsk Industrial District. In the sand wastes, the size category of- 100 µm is chosen, with the nickel and copper contents of 0.32 and 0.22%, respectively. The material constitutions of the initial sand waste and experimental samples were examined, and the optimal mode of their processing by a combination of low-temperature roasting with ammonia sulfate and bio-leaching is selected. The sand samples were mixed with ammonia sulfate and roasted, then the roasted mix was leached in water for 40 min with continuous stirring at a rate of 230 min-1, and the remained was subjected to bio-leaching using iron-oxidizing bacteria. The maximal recovery of metals is achieved at the temperature of 400 °С and at a sand and ammonia sulfate mass ratio of 1 : 3: nickel recovery was 73.2% and copper recovery was 71.6%. Bio-leaching produced additional recovery of more than 20% of metals. Thus, through recovery of nickel and copper reached 95.4 and 88.0%, respectively.
M. Laraba1, J. M. Menendez-Aguado2 1Mining & Geotechnolgy Department, Mining Institute, University of Tebessa, Tebessa, Algeria 2Asturias Raw Materials Institute, University of Oviedo, Asturias, Spain
Keywords: Kaolin ore, manganese, multigravity separator, Box-Behnken designs, response surface methodology
The objective of this study is purifying kaolin ore collected from Djebel Debbagh deposit, situated in eastern Algeria by the utilization of a multigravity separator. The chemical, mineralogical and microscopic analyses were carried out. These analyses reveal that the kaolin ore contains kaolinite as the main mineral contaminated with manganese considered as an impurity in this case. This last reduce significantly the quality of this kaolin and consequently limit its use as raw material in several industries. Three variables, namely, drum velocity, wash water flow rate, and shake amplitude of the Mozly multigravity separator were chosen for the analyses of their influence on the content, yield and recovery of manganese in mill tailings. The Box-Behnken designs and the response surface methodology were used. After optimization of the process variables, the maximal values of Mn content, yield and recovery were obtained. The predicted results were consistent with the experimental data, confirming the model correctness and the effectiveness of the parameters adjustment in MGS for manganese removal from kaolin.
N. F. Fetisova
Mining Institute, Ural Branch, Russian Academy of Sciences, Perm, Russia
Keywords: Waste water, mining industry, manmade geochemical barriers, treatment, structural parameters, efficiency, longevity
The practical application of manmade geochemical barriers in treatment of waste water in the mining industry is described. The studies of efficiency of natural and modified minerals in reduction of concentrations of heavy metals in mine waste water and in model solutions have positive results. The technical aspects of creation of manmade geochemical barriers are examined, namely, materials, sizes and designs aimed at enhanced efficiency and extended service life of the barriers. The geochemical barriers can be integrated in process flowsheets of operating mines, and are suitable for the independent use in closed mines where the cost of sophisticated waste water treatment systems is too high.
