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By C. D. Anderson, C. G. Anderson, P. R. Taylor

"Rare Earths have become critical for our energy and materials driven society. While primary production must ramp up to fill growing demands, the recycle of these strategic elements must also be initiated. This paper will outline the potentials of and metallurgical technologies employed for Rare Earths recycle from various secondary sources.INTRODUCTIONWhen investigating the recovery of rare earths from secondary sources it is necessary to understand the nature of the sources to be processed. As of 2009, the USGS reports the distribution of rare earths by end use, in decreasing order, was: chemical catalysts 22%, metallurgical applications and alloys 21%, petroleum refining catalysts 14%, automotive catalytic converters 13%, glass polishing and ceramics 9%, rare earth phosphors for computer monitors, lighting, televisions 8%, permanent magnets 7%, electronics 3%, and others 3% (USGS, 2011). Additionally, it is reported that the amount of recycling was quite small and consisted primarily of rare earth magnet scrap, although with the sharp increase in the price of rare earths, and the potential shortage in supply, focus in this area is continually growing. Thus, the opportunities, whether realistic or not, are extremely vast in the recycling of rare earth containing materials. The following subsections will present methods proposed for the recycling of rare earths based on the feed material type.RECYCLING OF RARE EARTH MAGNETSCurrently, investigations are ongoing in the area of recycling production scrap and end-of-life materials in the rare earth magnet industry. The following techniques illustrate potential methods for the recovery of rare earths from secondary RE magnet sources.Recycling of Rare Earth Magnet Sludge by Selective ChlorinationDuring the production of neodymium magnets, a by-product of production is the so called “magnetic sludge”. This by-product contains high amounts of neodymium, thus a process for the recovery of Nd has been proposed. In this process the Nd present is selectively chlorinated/distilled by the addition FeCl2 via the following reactions."

Jan 1, 2012

By M. Pearson, L. Zunti

Pressure vessels in hydrometallurgy and many chemical process industries throughout the world require the use of specific lining systems to protect the parent vessel materials from corrosion and/or abrasion. Typically, these lining systems are required for processes that are corrosive and operate at elevated temperatures. Two basic lining system types arc: 1) refractory linings in conjunction with an impervious corrosion resistant membrane, and 2) metal-clad vessels consisting of titanium or other corrosion resistant metal bonded to a carbon steel shell. Operating conditions play a key role in selecting the type of lining system to be utilized for a specific application. Lining systems in turn have an impact on the process vessel size, which ultimately affects the capital cost of the vessel. The capital costs for each type of lining system must be considered for each application, as well as maintenance concerns, quality control, and delivery. It is clear that operating conditions play a key role in the final selection of lining systems utilized for specific projects based on initial capital cost, life-cycle maintenance costs, and overall service life. This paper will examine the fundamentals of each lining system, their inherent technical strengths and weaknesses, and present relative cost comparisons for each lining system as they apply to specific operating conditions and vessel sizes.

Jan 1, 2004

By T. Güyagüler, U. Y. Önder

"This study investigated the psychrometric properties of ventilating air in GAL coal mines. Related measurements were done in underground openings and have been arranged as input data for computer programs prepared for ventilation network and psychrometric analysis.Results obtained from network analysis have been used for psychrometric analysis of ventilating air. Changes in heat and moisture content of air in two major path s between entry and discharge of ventilating air have been investigated. Psychrometric processes occurring in the mine were determined and are shown graphically in Figures 1 and 2. Special attention has been given to determine the changes in psychrometric properties and processes involved in the faces. Results are outlined in this paper.IntroductionThe psychrometric properties of mine air are important factors to mine productivity and efficiency. Therefore, psychrometric analysis should be made for all underground mines; any undesired situation observe d could be corrected by taking the necessary precautions.The analyses were done as a case study for GAL mines, the only mechanized lignite coal mine in Turkey. In this mine, workable reserve is about 300 million tons of coal and yearly planned production is 2.2 million tons. Production is continuing from a coal measure-bed having two coal seams with average thicknesses of 1.52 m and 1.72 m respectively. A 0.85 m shale band exists between these two seams.Two full y-mechanized faces, approximately 220 m long, usually work simultaneously. All measurements, including mine gases and air velocity, are done by sensors connected to a control room by a monitoring system.In the analysis, a line diagram is utilized to described the mine on which every junction and branch is numbered."

Jan 1, 1992

By G. O. Prickett, P. Somasundaran

An application of the statistical and computer techniques in basic mineral processing research is illustrated by means of a case history involving the study of starch adsorption on calcite. Multi-factorial experimental designs and computer techniques were used for determining the effect of different system variables, such as solution pH, sodium oleate concentration and starch concentration, and to obtain a mathematical model of the response. Response maps enabled the investigators to see the effects clearly and to predict the results of changes in factor levels within the design region. Use of time-shared computers and plotters made data processing and analysis efficient and relatively inexpensive.

Jan 1, 1973

By R. E. Whitehead

"Abstract - Alkali-alumina and MgO-alumina plots are an effective instrument for displaying chemical and mineralogical compositions of altered and unaltered rhyolites and rhyodacites. They reveal that most supposedly unaltered rhyolites, apart from those of Cenozoic age, have undergone losses in Na2O and gains in K2O. The extreme loss of Na2O from highly altered rhyolites immediately adjacent to VMS deposits is strikingly illustrated by alkali-alumina plots. MgO/Al2O3 vs. K2O/Al2O3 diagrams display a strong negative correlation between MgO and K2O that results from the conversion of sericite to chlorite. A similar negative correlation between MgO and whole-rock d18O is apparent on plots of these two parameters. Alkali-alumina plots underscore problems in selecting appropriate precursor compositions required for mass-balance calculations. Molar ratio plots are a viable alternative to such calculations. Sommaire -Les diagrammes alcali-alumine et MgO-alumine constituent un instrument efficace pour la représentation des compositions chimiques et minéralogiques des rhyolites et rhyodacites altérées et fraîches.Ces diagrammes révèlent qu’à l'exception de celles d’âge Cénozoïque, la plupart des rhyolites qualifiées de fraîches ont subi une perte de Na2O et un gain de K2O. L’intense perte en Na2O que l’on note dans les rhyolites fortement altérées associées aux gîtes de type SMV est particulièrement bien mise en évidence par le diagramme alcali-alumine. Le diagramme MgO/Al2O3 vs. K2O/Al2O3 montre une forte corrélation inverse entre le MgO et le K2O due à la conversion de la séricite en chlorite. Une corrélation inverse analogue entre le MgO et le d18O de la roche totale s’observe sur un graphe comparant ces deux paramètres. L’usage du diagramme alcali-alumine fait ressortir combien il peut être difficile de choisir un précurseur de composition appropriée pour des calculs de balance de masse. Les diagrammes de rapport molaire constituent une alternative à de tels calculs."

Jan 1, 2006

By M. Tardif, F. L. -Lavoie, M. Ruel

"In mineral processing, it is often very difficult to reliably measure several key operation variables. The harsh environment and high temperature encountered in pyrometallurgy processes lead to some difficulties when selecting the instruments, valves and actuators. If an important variable cannot be measured or manipulated adequately, controlling it can really become a big challenge. Sometimes, it is simply impossible to find the perfect equipment for the task. To help overcome these difficulties, a different approach is required. This approach will not correct the inherent problems related to the instruments and valves, but will cope with these problems. This article will demonstrate how modern process control techniques can be used to solve complex problems while remaining easy to implement. In this article we will described how soft sensors and multivariable fuzzy logic control were implemented at Koniambo Nickel to stabilize the furnace feed and allow for safe and reliable operation of an 80 MW DC arc furnace.INTRODUCTION Process Overview The process plant at Koniambo Nickel SAS is located in the North Province of New Caledonia, 310 km north of Noumea. The nickel-bearing ore is mined in the nearby Koniambo massif. After being screened and crushed, the ore is transported to the processing plant using a 12 km conveyor. After stacking in two blending piles, the ore, containing 2.3% nickel, is fed to the processing plant where it will go through the NST process (Nickel Smelting Technology) before being sent to refining and shotting. This article will focus on the improvement to control of the NST processes. The first steps of this process consist of milling the ore and removing all moisture through calcining (Figure 1)."

Jan 1, 2017

By N. R. Thornton

This paper discusses the rapid growth in the application of instrumentation for metallurgical process control. It covers such methods as ultrasonics, pulp density measurements, on-stream X-ray analysis and reagent control, as well as the expanding use of computer control and data acquisition.

Jan 1, 1971

By Farzad Khodabakhshi, Adrian P. Gerlich

"Multi-pass friction stir processing (FSP) was performed to fabricate a new Al-Mg-Graphene nanocomposite. Microstructural developments and distribution of graphene were studied by using electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM) analysis. In the stirred zone (SZ), grain structure was refined down to about 2 µm attributing to the operative dynamic restoration mechanisms and the locking effect of graphene phase. As a result, the yield strength of Al-Mg alloy was improved more than two times due to incorporation of graphene nano-sheets. Also, the indentation hardness resistance of nanocomposite was increased up to ~60%.INTRODUCTION Aluminum-matrix nanocomposites have garnered significant in recent years due to their superior performance and potential advantages for several industrial applications including the automotive and aerospace sectors. Among various reinforcing nano-materials, carbon-based structures featuring sp2 or sp3 hybridization bonds have been found to offer considerably improved physical and mechanical properties. Such carbon allotropes form at micro- and nano-scales including; graphite, carbon nano-tube (CNT), nano-fiber, and graphene. The potential of two-dimensional (2D) carbon materials was introduced in 2004, with the development of graphene as an alternate 2D allotropic form of the carbon structure with a honey-comb lattice at the atomic-scale. It has been shown that it is currently among the strongest materials ever tested with an intrinsic tensile strength of 130 GPa and Young’s modulus of 1000 GPa, and also offers unique thermal and electrical properties.To fabricate metal-matrix nanocomposites reinforced by graphene nano-sheets with typical metallurgical processing techniques, some attempts have been reported in the literature for various solid-state techniques including; hot rolling, mechanical alloying, and friction stir processing (FSP) of pre-cast plates or surface dispersed graphene oxides. The main challenge in those methods was to facilitate the considerable high temperature and pressure for attaining a uniform dispersion of the nano-sheets during the consolidation process. In most cases, significant difficulties have been reported in obtaining a uniform dispersion of graphene within the metal matrix. Among various techniques for production of metal-matrix nanocomposites, FSP has attracted significant attention as a method of surface modification since it was first reported by Mishra et al. In this process, a non-consumable rotating tool is plunged into the surface of material for the aim of microstructure modification. Extreme material plasticity is induced without melting as a result of friction between the tool and workpiece. Frictional heating and severe plastic deformation induced by the FSP process enables metal matrix nanocomposite fabrication by softening the base material and mechanical stirring to disperse the reinforcing nano-materials into the matrix."

Jan 1, 2017

By K. Reipas

"Westmin Resources Ltd. operates the 3300 TPD H-W underground copper/zinc mine on Vancouver Island. Ore storage underground is handled in a 6000 tonne coarse ore bin and a 3000 tonne fine ore bin. Both of these bins have experienced significant wear since excavation and construction in 1985. Wear problems have included both deteriorating rock walls as well as worn out steel liners and concrete at the discharge points from the bins. Extensive rehabilitation work was completed in 1993.The basis o/this paper is the rehabilitation work done on the coarse ore bin. The design and installation of ground control measures are discussed. The bin access methods used to allow the work to proceed quickly and safely are also presented. This involved the use of a Tekfoam safety bulkhead to protect workers.IntroductionMine DescriptionThe H-W mine was commissioned in 1985. Mine access is by vertical shaft with most production areas at a depth of about 500 m. Host rocks are composed of andesite and rhyolite. Mine capacity of 3300 tonnes per day is achieved mainly by longhole open stoping methods, complemented by room and pillar mining. Metals recovered from the massive sulphide ore are copper, zinc, gold, and silver. Mineable reserves at January I, 1994 were 9.7 million tonnes."

Jan 1, 1995

By J. G. Schofield, C. G. Tan, R. J. Ord

"Most electric furnaces in the nickel and copper smelting industries are still fitted with conventional electrode holders which consist of water-cooled electrical contact clamps and a pressure ring. The water cooling exerts a significant cooling effect on the electrode column. The importance of controlling the temperature of the Soderberg electrode paste at the contact clamp area is examined, using in-plant experience and computer simulation of the paste melting and baking process. In addition to the effect of water-cooling, the effect of other variables, including the mantle air temperature, the electrode current, the furnace freeboard temperature and the electrode slipping rate are discussed. Ways in which the variable heating conditions in the paste melting zone can be controlled are outlined.IntroductionIn most non-ferrous electric smelting operations, the breakage of Soderberg electrodes is an infrequent, isolated occurrence. Occasionally, however, a rash of breakages may be experienced on a particular furnace for what appears to be no obvious reasons. The extent of the breaks may not exhibit a uniform pattern; sometimes the break may be less than half a metre above the electrode tip; at other times it may be at or just below the roof level. The latter type of break is, of course, the most dangerous since it is closest to the non-baked, weak portion of the electrode paste column. No matter where the breaks occur, they result in abnormal furnace power, charging and tapping conditions and loss of production while the new electrode section is slipped and baked. On a six-electrode furnace, breakage on one electrode has the immediate effect of reducing the total furnace power by one-third. On a three-electrode furnace, the effect is more drastic, one half of the power being lost."

Jan 1, 1995

By M. H. Colebrook

Nickel laterites contain about 70% of all continental or terrestrial nickel resources; therefore the recovery of nickel from lateritic ores has large economic significance. The processing of lateritic ores involves the preparation and movement of concentrated aqueous suspensions. However due to complex characteristics and non-Newtonian properties, ranging from shear-thinning to shear-thickening and from thixotropic to rheopectic, a basic understanding of the flow behaviour must be developed. This understanding will assist in the development of new plants and the operation of existing plants. The work in this paper involves the characterization of three ore types from the Vermelho ore deposit to categorize them as rheologically simple to complex. Rheological testing was also conducted on pure mineral samples that represent the main minerals in these samples. The results show that the rheological properties of the ore types can be related to the surface properties and physical characteristics of the main mineral constituents.

Jan 1, 2006

By A. Siegmund, F. Mucciardi, Z. Yuan, B. Bulnes

With conventional heat pipe science as the starting point, a new heat transfer technology --- termed Thermopump technology, has been developed at McGill University and is now being tested at a number of industrial operations. This technology is of particular importance for transferring energy in high temperature / high heat flux environments where solutions based on current techniques are not available. One important application for this technology is in the metals recycling area wherein this technology has been used to make a waterless, non-consumable, high efficiency Thermopump oxygen lance. The viability and efficiency of this oxygen lance have been demonstrated by preliminary plant trials in a reverb furnace for the recycling of lead-acid batteries at the RSR Corporation. Full-scale commercial trials of the Thermopump (TP) oxygen lance have been carried out at the RSR Corporation. The results from these tests will be presented. In addition, some applications of the Thermopump technology for other metal recycling processes will also be discussed in this paper.

Jan 1, 2004

By A. Kapoor

Gold mill effluents contain toxic pollutants such as cyanide (CN), thiocyanate (CNS), ammonia (NH4-N), and a variety of toxic metals. Various practical and economical technologies are in use for the removal of CN and toxic metals from gold mill effluents, however, the removal of CNS and NH4-N is challenging. The presence of CNS and NH4-N may make effluents toxic to aquatic life. The new Canadian Metal Mining Effluent Regulations will require mine effluents to be nontoxic. As a result, there is a need to develop practical and economical technology for CNS and NH4-N removal. The Mine Effluents Program in the Environment Group is presently evaluating biotechnology processes for the removal of CNS and NH4-N from gold mill effluents. The processes being evaluated are attached growth systems such as a Rotating Biological Contactor (RBC) and completely mixed suspended growth systems such as a Sequencing Batch Reactor (SBR) operating in a batch mode. The research to date at MMSL has shown that the RBC is very effective in removing CNS and NH4-N from simulated effluents. The NH4-N removal project showed that the RBC is capable of removing 0.8 g NH4-N/m2 of RBC disk area per day at an average temperature of 4.5 oC and hydraulic loading rate of 0.02 m3/m2/d. The RBC was also found to be very effective in removing CNS (feed = 200 mg/L and effluent < 1 mg/L) at 8 oC and a hydraulic loading rate of 0.02 m3/m2/d. The SBR was effective in removing CNS and NH4-N (generated from CNS degradation) at SBR operating conditions of two-12 h treatment cycles and a temperature of 12 oC. The end product of CNS and NH4-N oxidation was NO3-N, which is relatively non-toxic.

Nov 1, 2002

By Rick Steen, Weldon Read, Morrism Tracy T.

Edging for starter sheet blanks used in conventional copper refineries has always been problematic for getting the edging to seal and adhere to the titanium material used for the blank so that copper is prevented from plating under the edging and cause undo problems in getting the copper sheets to separate from the blanks. A method was developed at the Amarillo Copper Refinery utilizing an injection molding process that better adheres the edging material to the titanium that makes the harvesting of starter sheets much easier to the point that robots are now used to strip with and which holds up very well to the unforgiving physical nature of the electroplating process. It is believed that this technology could be successfully utilized for permanent cathodes as well. INTRODUCTION ASARCO LLC (Asarco) was organized in 1899 as the American Smelting and Refining Company. Originally a consolidation of several lead-silver smelting companies, it evolved over the years into an integrated producer of primary non-ferrous metals, including copper, lead and zinc and associated co- products (Marcosson, 1949). Grupo México, S.A.B. de C.V acquired Asarco in 1999. Today, Asarco is a vertically integrated producer of primary refined copper and associated co-products such as gold, silver, molybdenum, selenium and tellurium. Asarco operates three open-pit mines and mills and two solvent extraction-electrowinning (SX-EW) plants all in Arizona plus a copper smelter in Arizona and a copper refinery in Texas. Figure 1 illustrates how the copper metal comes out of the ground at the mine and ends up as a refined product at the refinery. The copper refinery in Texas is known as the Amarillo Copper Refinery (ACR) and is located in Amarillo, Texas. It was built in 1975 to replace 3 other aging refineries and was designed to produce 550,000 tons (500,000 MT) of refined copper per year using conventional starter sheet technology. At the time it was commissioned it was the largest tankhouse in the world at just under 1/2 miles long under one roof.

Jan 1, 2019

By D. Lopez, D. L. Doerr, T. J. Drake

Automated scanning electron microscopy has been widely used in recent years for gold and other precious metals characterization. However, application of this technology is resource intensive and in most instances needs specialized technical personnel to process the samples and information. Newmont Metallurgical Services (NMS) has recently acquired an ASPEX SEM. The ASPEX SEM offers some significant benefits/improvements in sample preparation and sample processing time. NMS and ASPEX have been working together to develop an approach utilizing this technology for the minerals processing industry and specifically for gold characterization.

Jan 1, 2011

By H. Y. Sun, Q. Y. Tan, X. P. Niu, L. Li, Y. Jia, R. M. Ruan

During bioleaching processes of sulfide minerals, the sulfide minerals act as the natural habitats for acidophiles, of which, most are autotrophic iron and sulfur oxidizing microbes. These microbes acquire energy by oxidation of sulfide minerals, and play crucial role in bioleaching processes. In the industrial bioleaching heaps, microbial community and their activity are highly related to engineering configurations, while the optimized industrial operation can help to fast dissolution of aim minerals and acid/iron balance under optimized microbial condition. Microbial community succession and activity formation, the function of microbes to mineral dissolution, the mechanisms to promotion and inhibition of sulfide minerals oxidation, and the industrial instances for microbial community regulation were reviewed. For these instances, promoted microbial activity helped to fast pyrite oxidation for sulfuric acid generation, which realized zero sulfur acid addition to the irrigation solution in the initiation of a bioleaching heaps. High microbial activity by optimized operation parameters improved Cu leaching efficiency during the heap bioleaching process. And also by inhibition of microbial activity, especially the iron oxidizing microbes, the excessive pyrite oxidation can be inhibited, which helped to the acid/iron balance during heap bioleaching. INTRODUCTION Around the world, high grade copper ore are exploited, while barely new high-grade deposits are succeeded, the copper grade of ore deposit is constantly decreasing. The increasing copper demands worldwide requests to process these low-grade ore deposits. Processing of low-grade ores are not economical by usual extraction processes. Heap leaching is a cheaper process for recovery of low-grade ores, and has been applied to extract valuable metals from sulfide minerals worldwide, such as copper, gold, uranium and nickel (Gericke et al., 2009). Heap leaching process has greatly decreased the economic grade and expanded the recoverable ore reserve worldwide (Brierley, 2008). It is usually carried out in the open environments, and could process huge amount of ore (usually in millions of tonnes in one reactor) in the heap reactor (Gericke et al., 2009). For copper sulfide, especially the secondary copper sulfides, heap (dump) bioleaching is successfully applied. Heap bioleaching process is cost saving, and sometimes can be achieved without adding chemical into heaps, by microbial fixing of the atmospheric N2 and CO2, and generating oxidant Fe3+ and sulfuric acid in heaps from oxidation of sulfide minerals. Also heap bioleaching is environment friendly by cycling use of the leaching solution, and without exhaust emission.

Jan 1, 2019

By N. K. Jaber

The "Pidgeon Process" for the extraction of magnesium from dolomite ore utilizing ferrosilicon as the reducing agent has been studied extensively by active metallurgists such Mr L,M, Pidgeon the father of this process, Most of the work sited so far has focused on heating the (FeSi/MgO,CaO) briquette mix under vacuum in stainless steel retorts by external fuel hydrocarbon heating, In this work Electrical Induction Heating was employed as the heating method whereby the briquette mix was placed in a steel crucible around which an Induction Heating copper coil was wound and placed inside in a stainless steel vacuum tank, It was observed that by virtue of the fast Induction Heating method utilized in the silicothermic extraction process higher reduction temperatures were reached in shorter periods of time due to fast heat transport into the ore charge mix, This facilitated shorter metal reduction times as compared to the conventional fuel heating methods.

Jan 1, 2006

By Mehmet F. Taner

"The East Sullivan Stock (ESS) is a small, composite felsic alkaline pluton of presumedlate Archean age in the Val d’Or mining district. Three main facies have been distinguished: mon-zonite sensu stricto, porphyritic monzonite, and green trachytic porphyry. This monzonitic group ofrocks is of relatively homogeneous composition with high abundances of Na2O, K2O, Ba, Sr, Rb, Zr,Mo and LREE. The alkaline ESS is distinguished from other igneous units in the Val d’Or miningdistrict, such as the Bourlamaque Batholith, by relatively high concentrations of Ba, Sr, Rb, Mo, Cuand Au. The ESS hosts many base (Cu, Mo) and precious (Au) metal occurrences, including: (1)porphyry style Cu-Au-Mo disseminated sulfde deposits, (2) Cu-Au deposits in volcanic rocks near the ESS contact, and (3) pyritic gold mineralization in east-west trending shear zones. The ESS is well defined by concentrical zoning on the aeromagnetic vertical gradient color map, and displays four linear trends, which are assumed to be structural lineaments, at 035°-055°, 320°-300°, east-west, and north-south. The main mineral occurrences related to the stock display a preferred spatial association with the east-west linear magnetic trends.The ESS is preferentially located along a major structure and was emplaced late in the evolutionof the Abitibi subprovince like other felsic alkaline plutons. This stock is similar to late-tectonic min-eralized felsic alkaline intrusions of the Kirkland Lake and Larder Lake mining districts in Ontario, and to the Allard stock in the U.S.A. which is associated with gold and base metal mineralization. Similarities also exist with younger alkaline plutons associated with Cu-Mo-Au porphyry deposits in the Canadian Cordillera, which formed in tensional tectonic environments. The felsic alkaline magmamay have formed by partial melting of deeply buried supracrustal rocks, concomitant with the development of deep fractures such as the Cadillac Fault. In such an environment, hydrothermal solutions carrying remobilized metals from deep supracrustal rocks may have deposited gold and base metals in structural traps. Plutons similar to the ESS should be good targets for mineral exploration. Copyright © 1996 Canadian Institute of Mining, Metallurgy and Petroleum."

Jan 1, 1996

By Akiyoshi Horiuchi, Manabu Kanno, Shigeki Sato, Taro Aichi

"AKITA ZINC Co., Ltd. (Iijima Zinc Refinery), jointly owned by DOWA METALS & MINING Co., Ltd.(DMM), has used the company’s own hematite process for iron control since the beginning of operations in 1971. The hematite process consists of reductive leaching with SO2 gas and iron removal in autoclaves by high temperature hydrolysis. This process enhances not only zinc recovery but also the recovery of gold, silver, copper, lead and rare metals, which is carried out at another DOWA metallurgical plant. All by-products produced in the hematite process are marketed and sold. This paper presents an overview of the hematite process and the recent process improvements made.INTRODUCTION DMM carries out mining and smelting activities for precious metals, PGMs, rare metals and base metals such as copper, lead and zinc. It owns KOSAKA SMELTING & REFINING, producing copper and lead, and the AKITA ZINC Co., Ltd. (AZC) in Akita Prefecture. DOWA is a specialized smelting company which has established a metallurgical complex for copper, lead and zinc, including a recycling business. AZC was established in 1971 at a production capacity of 72,000 t/y zinc; it is jointly owned by DMM and five other non-ferrous metal companies. AZC has increased its capacity continuously and now produces 210,000 t/y of zinc. Figure 1 shows the changes in zinc production and capacity at AZC."

Jan 1, 2016

By V. Bondarenko

The importance and necessity of gas hydrates deposits development followed by natural gas extraction is considered in the present paper. Analysis is given to world sources focused on methane hydrates formation conditions. Information covering the most perspective gas hydrate deposit of the Black Sea is presented in the article. Two most common methods of gas hydrates development ? thermo stimulation and inhibitor injection are analyzed presenting their comparative characteristics. Basic scientific trends and developments of underground mining department in the field of gas methane extraction from gas hydrates are scrutinized. Schemes and methods of natural gas hydrates development are shown together with formulas, parameters and factors influencing the extraction process. Also the analysis is given to the possibility of gas hydrates formation from methane-air mixtures of degassing wells from coal mines of Ukraine. Improved experimental unit for gas hydrates formation under laboratorial conditions is presented with its basic characteristics. General conclusions and basic tasks requiring further research are given in the end.

Aug 1, 2013