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The status quo of ecological rehabilitation in metal mine in China and progress in the technology for ecological rehabilitation are presented, including soil reconstruction, soil improvement, plant selection. The present and future research fields are suggested: basic theory of ecological rehabilitation, operative technology of ecological rehabilitation, new technology application research and ecological rehabilitation plan, management and policy.

Jan 1, 2014

The use of controlled recirculation can be dated back to the early 1930s. Although this method has been applied in many mines since then, a generalized comprehensive network analysis is still lacking. This paper presents a unique approach in which the ventilation network with a controlled district recirculation is divided into two subsystems: a main subsystem and a recirculation subsystem. The subsystems are analyzed individually and the results and their relationships are then integrated into discussions of the total ventilation system. The analysis of the recirculation subsystem is facilitated by introducing a non-dimensional parameter A, which represents the ratio of the air quantity for the working face to that for the subsystem. As a result, fan and regulator pressures and air power for various recirculation arrangements can be effectively expressed as a function of A and the subsystem air quantity. Numerical examples are included.

Jan 1, 1995

By A. M. Venter

"SynopsisThe availability of advanced characterization techniques is integral to the development of advanced materials, not only during development phases, but in the manufactured components as well. At Necsa, two modern neutron diffractometers equipped with in-situ sample environments, as well as complementary X-ray diffraction instruments, are now available as User Facilities within the National System of Innovation in support of the South African research and industrial communities. Neutrons and X-rays, owing to their different interaction mechanisms with matter, offer complementary techniques for probing crystalline materials. Both techniques enable nondestructive investigation of phenomena such as chemical phase composition, residual stress, and texture (preferred crystallite orientation). More specifically, the superior penetration capabilities of thermal neutrons into most materials allows for the analysis of bulk or localized depth-resolved properties in a wide variety of materials and components. Materials that can be investigated include metals, alloys, composites, ceramics, and coated systems. In particular, depth-resolved analyses using neutron diffraction complements surface investigations using laboratory X-rays in many scientific and engineering topics. The diffraction techniques can add significant downstream value to the anticipated nuclear industry development activities.IntroductionMaterials characterization is central in understanding the relationship between the structure, properties, and performance in order to engineer materials that fit the performance criteria for specific applications. This is conveniently represented in the form of a tetrahedron, generally known as the material science paradigm (Figure 1).The availability of advanced characterization techniques is integral to the development of advanced metals, not only during development phases, but in the form of manufactured components. At Necsa (South African Nuclear Energy Corporation), modern X-ray and neutron diffraction instruments are now accessible to the South African research and industrial communities. These facilities enable nondestructive investigations of materials and components that could add significant downstream value to the anticipated nuclear industry development activities."

Jan 1, 2015

By Yoichi Takeda

The CaO-FeO,-Cu20 slag has been practically applied to continuous converting of copper, and also has potential for refining of copper. Liquidus lines of the slag system and phase stability diagram for the liquid slag and the existing solid compounds under copper saturation are presented. Liquidus composition was determined by chemical analysis of slag sample saturated primary solid. The temperatures of invariant equilibria were investigated by thermal analyses. Oxygen potentials on the liquidus lines, the univariant and invariant equilibria were estimated from the relation slag composition and oxygen potential that relation was confirmed in separate experiments.

Jan 1, 2003

Coal-derived flue gases contain CO2/SO2 and these contaminants preferably have to be captured by cheap sorbents. This remediation approach is from the standpoint of addressing issues such as global warming, acid rain and development of Advanced Power Generation Systems and to realize the economic gain as well. Conventional and existing dry scrubbing technologies use regenerable sorbents which are pollutant specific and require expensive stabilizers in order to attain versatility. This paper discusses the use a novel class of sorbents prepared from the heavy metal contaminated Berkeley Pit water (Butte, Montana) by a proprietary process developed at The University of Nevada, Reno. These sorbents are activated mixed spinel ferrite (MxFe,_X04)' Preliminary experimental results show that the sorbents have good desulfurization and CO2 decomposition capacities. The decomposition effectiveness of these mixed spinel ferrites was studied at 300°C and compared against the synthetic magnetite obtained from ferrous sulfate solution in our laboratory. The results indicated that the mixed spinel ferrite had good affinity for the adsorption and decomposition. The CO2 decomposition data of both sorbents fitted the first order reaction kinetics. Even though the surface area of the magnetite was higher than that of mixed spinel ferrite, the CO2 decomposition rate of the mixed spinel ferrite was estimated to be 2.5 times higher than that of magnetite under identical conditions. The carbon analysis deposited on the sample indicated that the CO2 was 100% decomposed into carbon and other carbon! hydrogen compounds by the mixed spinel ferrite whereas the conversion was 43% by the magnetite. In terms of specific adsorption of carbon, ferrite was 3-5 times more efficient than magnetite.

Jan 1, 1996

By Ruddle R. W.

An outline account is given of the smelting of copper and the chemistry of the process. A table provides compositions of the more important minerals from which copper is won by smelting. Roasting is discussed as is smelting using reverberatory furnaces, blast furnaces and flash smelting. A brief discussion of converting covers the upright (Great Falls) converter and the horizontal (Peirce-Smith) converter.

Jan 1, 1953

By John Dasher

The impetus given to mineral dressing arid chemical engineering by the war has placed many persons without previous experience in positions where they are concerned with the size of solid materials they are testing. Many good textbooks cover this field in considerable detail but are more concerned with the "why" than with the "how" For beginners and those to whom size is not of primary concern, this brief circular has been prepared. Refer-

Jan 1, 1942

By D. C. Fraser, W. J. Scott

"Airborne electromagnetic surveys were flown during 1965 in the Moose River area of Ontario. The systems used were INPUT Mark II and the Canadian Aero Otter. Anomalies indicated by both systems were located on the ground with vertical-loop EM. Two such anomalies were drilled, with no explanation being found in the bedrock geology. Subsequent seismic, resistivity and gravity surveys indicated that the sources of these anomalies lay in the overburden. Current work in the similar geological environment of the Winisk River area has shown that comparable AEM anomalies can still be misleading. The lesson to be, learned from these experiences is that additional geophysical work can help to resolve doubtful cases before drilling decisions are made."

Jan 1, 1973

By Danuta Szyszka

This paper presents results of tests performed to determine minimum concentration of a surfactant used at which coalescence of air bubbles during flotation has low probability to occur. The measurements of the critical coalescence concentration, also known as CCC, were carried out in a device consisting of glass cell into which air was pumped by peristaltic pump through capillaries. The flotation foam was recorded with a high resolution digital camera. Basing on the video records, average diameters of the air bubbles were measured and the values obtained were subsequently used to determine the CCC values. The author of paper determined the CCC values of surfactants tested using the linear regression method, and subsequently analyzed the results obtained. To define initially the capability of a tested surfactant to flotation, efficiency of multiparticle model flotation and flotation of individual size fractions were determined in a flotation apparatus for laboratory use in the presence of only foam making agent at CCC value pre-determined during the tests previously carried out. The tests of coalescence phenomenon were carried out with use of selected flotation frothing agents.

Jan 1, 2014

By D. Lambert

Process modeling for large deformation metal forming processes has been developed into a very successful tool in commercial applications during the last two decades. DEFOR.MTM is a well-known metal forming process simulation program used by many industrial and research institutions. Recent developments include the ability to model multiple deforming body behavior during multi-pass pack rolling and microstructure prediction during multi-pass shape rolling. This paper summarizes how DEFOR.MTM can be applied to a number of rolling processes and briefly describes preliminary work carried out using the ALE technique. Keywords: Simulation, Rolling, Pack, Shape, Microstructure, FEM, ALE, Tantalum

Jan 1, 2003

By Hui Zhang, Fei Yang, Tong Guan, Guangqin Fu, Lihong Deng, Yuanlin Chen, Xiaotong Zhou

"For a copper-sulfur polymetallic mine in south China, the main valuable minerals were chalcopyrite, pyrite and pyrrhotite. The flotability of pyrrhotite was similar with chalcopyrite and pyrite and it was easy to be oxidized. As a result, the indexes of copper concentrate and sulfur concentrate were unsatisfactory. Furthermore, the recycling of tailings water ulteriorly deteriorated the technical indexes of copper-sulfur ore beneficiation. After a large amount of experimental studies, under the condition that the tailings water recycling rate was 100%, the copper concentrate with a grade of 22.25%Cu and a recovery of 82.46% on average was obtained for the raw ore containing 0.517%Cu, 15.94%S, 25.46%Fe on average, through using new technology “magnetic separation-flotation” and effective adjustment of parameters in the industrial test which was continuously conducted for 14 shifts in 5 days with a scale of about 75t/d. Comparing with the production indexes (the copper concentrate with a grade of 17.49%Cu, the recovery was 62.27%) during the corresponding period, the grade of copper concentrate increased 4.76%Cu, and the recovery increased 20 percentage points. Besides, the indexes of sulfur concentrate gained a considerable improvement. Currently, the new technology was adopted in the design of the new-built plant with a scale of 7000t/d of this mine. The new technology provided powerful support for the tailings water recycling and indexes improvement of copper-sulfur ore beneficiation.INTRODUCTION Chalcopyrite was usually associated with pyrite and pyrrhotite in copper-sulfur ore. Due to the similar flotability, it was difficult to obtain copper concentrate and sulfur concentrate with high grade. Furthermore, sulfide ore was easy to be oxidized and a large amount of ions formed in the pulp by the dissolution of minerals, which made the pulp become acidic. As a result, pyrite and pyrrhotite were easy to be activated in acidic solution and their flotabilities became stronger. Meanwhile, hydrophilic film formed on the surface of chalcopyrite in raw ore. The flotability of chalcopyrite became weaker and it made the separation of chalcopyrite from pyrite and pyrrhotite more difficult. So it was more difficult for copper and sulfur recovering with the recycling of tailings water containing high content of heavy metal ions and reagents."

Jan 1, 2018

By W. W. Bake

INTRODUCTION IN IN JUNE, 1943, the main pillars of the Beattie Mine glory hole failed, allowing over a million yards of wet clay and debris to flow into the mine, completely filling all workings to within seventy feet of the 3rd level. The resulting Job of clearing these workings and rehabilitating the mine represents a unique and hazardous operation, seldom, if ever, previously encountered in Canadian mining. The purpose of this paper is to describe one phase of this operation -that of cleaning and rehabilitating the mine from the 6th to the 9th level -to outline briefly the events which led up to this work and to describe the techniques and costs involved. It will be noted that such costs, methods, and performance figures as are dealt with in this paper refer only to work in the internal shaft and adjoining workings from the 6th to the 9th level, previous work having been done under other supervision and management. The Beattie mine is in Duparquet township, northwestern Quebec, twenty miles northwest of the town of Noranda and twenty-three miles southeast of the town of La Sarre. The mine and the town of Duparquet, which it?supports, are accessible by highway from Noranda throughout the year. Production at the Beattie mine began in May, 1933, and up to June, 1943, twenty-one million dollars in gold and silver had been recovered from five and a half million tons of ore.

Jan 1, 1951

By Ventsislav Stoilov, Angel Angelov, Ivan Korolev, Antti Remes, Todor Pukov, Stoyan Gaydardzhiev

"The process modeling and simulation studies aim for better process operation and favorable environmental impact. The objective of this work is to set up a simulation model of the Assarel copper flotation circuit for planning and optimization of the process with the aim of increased metal recovery. The model is parameterized based on laboratory flotation tests of ore samples from the Assarel mine together with mineralogical studies by X-ray diffraction (XRD) and Mineral Liberation Analysis (MLA). A combination of several techniques allows reliable identification of mineralogical composition of the selected samples. The changes in the proportion between sulfide minerals in various products along the circuit have been also documented. Further, this information is used in the simulation model and in data reconciliation procedures for establishing mass balance. The simulation accuracy is studied by comparing the simulations with the plant survey based mass balance. Constructed simulation model can be used to run alternative process scenarios. As an example, the flotation circuit performance with different reagent regimes is simulated based on data from batch flotation tests. Two reagents were considered for this purpose, dithiocarbamate-based one and xanthogen formate/mercaptan blend. It has been revealed that these reagents do not have the same influence on the selective flotation. The one improves flotation of gold and overall recovery but without notable selective action. In contrast, the other showed better selectivity towards copper, rejecting more gangue and lowering gold recovery. The model is also applicable for process optimization studies with different feed compositions, flowrates and circuit configurations. INTRODUCTION In the pursuit for elevated technological indicators, finding an optimal set of process parameters fully utilizing the potential of the equipment is a key factor to success. Over the past decades, there has been a substantial development in flotation circuit optimization through performance benchmarking using metallurgical modelling and steady-state computer simulation. Practical simulation engineering tools are based on experimental data obtained from laboratory tests and from plant surveys and operation data. With the help of flotation models, it is possible to study grade-recovery response with different feed compositions and throughputs, and with various cell-operating parameters, as well as to evaluate and design different flowsheet configurations. Outotec’s HSC Chemistry® software, which incorporates simulation and mass balancing modules alongside with several other tools, can assist with this optimization (Mattsson et al., 2015)."

Jan 1, 2018

By Zhigan Deng

Ni–Mo ore is a black shale containing amorphous colloidal sulfides which have highly active. The oxygen pressure leaching behavior of nickel from black shale in aqueous media is presented. The effects of agitation speed, temperature, oxygen partial pressure and particle size on the rate of nickel leaching were determined. The results indicate that at low temperature hydrothermal and excess oxygen presence, the amorphous sulfides are easily oxidized to sulfuric acid and sulfate, and leaching nickel. The mathematical analyses of the experimental data for various experimental conditions indicated that the dissolution process was controlled by the chemical reaction during the early stage of dissolution, and was then controlled by liquid-film diffusion. In the initial stage of leaching, the reaction depends on oxygen partial pressure.

By Michelle Cardinale Souza Silva Macedo

Neste trabalho, o comportamento eletroquímico das ligas Ti-35Nb-xTa (x = 0; 2,5; 5,0; 7,5)Ta (% em peso), solubilizadas e resfriadas em água, foi investigado em meio de NaCl a 0,9% mol/L através de testes de polarização anódica e medidas de impedância, micrografias e DRX. Os ensaios eletroquímicos mostraram que as ligas contendo tântalo apresentam uma maior resistência à corrosão que a liga sem tântalo. Além disso, os ensaios eletroquímicos em conjunto com as micrografias e DRX indicam que a composição Ti-35Nb-5Ta é a que apresenta maior resistência à corrosão no meio estudado, pois além de ocorrer uma estabilização da fase ?, o refino do grão foi menos pronunciado e por esse motivo minimizou o surgimento de microcélulas eletroquímicas.

Aug 16, 2017

By Frank D. Lamb

"INTRODUCTION The use of beryllium and its alloys has come into prominence in the last 15 years and increased considerably during the war. In contrast to other light metals, such as aluminum and magnesium, beryllium is relatively hard, has a high melting point (1,285° C.), and other properties that make it resemble steel in many respects. It has a specific gravity of 1.85, is only slightly heavier than magnesium (specific gravity 1.74), and is appreciably lighter than aluminum (specific gravity 2.7). Its lack of ductility prevents its use as a structural material, but this difficulty may be overcome in the future by the use of various alloy forms. The only important commercial alloy in which beryllium is used today is with copper. The addition of small percentages (1/2 to 2 percent) of beryllium to copper imparts properties to the alloy that make it desirable for use in springs carrying electrical current, particularly at high temperature. Many other uses of berylliam are known, and new uses are being found constantly that make the metal of increasing interest.Possibly the main factor preventing the use of more beryllium is the lack of a large source of beryllium ore. Many beryllium minerals are found as minor constituents of natural deposits, some of the more common ones being beryl (Be3Al2(Si03)6), chrysoheryl (Be A1204), helvite (3(Mn, Fe) Be Si04. MnS), and phenacite (Be2Si04). Of the known beryllium minerals, beryl is by far the most common and has been found distributed rather widely throughout the world. It usually occurs associated with granitic rocks and is commonly found as a constituent of granitic pegmatite."

Mar 1, 1947

By A. G. Journel, CH. Huijbregts

"Centre de Morphologie MathématiqueSpecial problems arise in the evaluation of lateritic-type orebodies (Ni-Co, bauxite) or, more generally, orebodies affected by surface weathering. In this type of orebody, the vertical grade distribution shows, from the hangingwall downwards, a systematic increase followed sometimes by a certain decrease, or vice-versa. These trends appear together with irregular variations from one drill bole to the other.The problem is to characterize a vertical structure that is representative not only of the drill hole but of an entire panel or zone of influence, in order to define mineable thicknesses for given cut-off grades. The vertical grade distribution observed on the drillhole is replaced by a new curve, called 'derive' (drift), which is computed by 'universal kriging'.Once the vertical study is completed, new 'service-variables' are defined in the horizontal plane, such as mineable thickness and the corresponding average grade, economical functions (combination of the grades of several minerals). The local and global estimation of these variables can then be performed by a simple bi-dimensional kriging plan. The global estimation is summed up by several tonnage-cut-off grade curves.The practical valuation according to the above scheme of a New Caledonian lateritic nickel orebody is presented."

Jan 1, 2014

By M. Hopf

Numerous developments and improvements have been made to tap-hole designs. On the other hand, there are very specific designs in operation that have endured for many years without any modification. Nobody likes design changes because of risk - the risk of atypical wear, potential hazards, and costly repairs entailing enormous production losses. So the philosophy ‘never touch a running system’ is maintained, because among other things there is no efficient working monitoring technology for tap-holes. In the past few years a couple of new technical solutions have been investigated and developed. Not all theoretical solutions are possible in practice. However, metallurgists are inventive, and the last word regarding efficient working tap-hole monitoring technologies has not yet been spoken.

Jan 1, 2014

By W. W. Adams

"Although rock-dust is an effective and generally recognized preventive of wide-spread explosions in bituminous-coal mines and although in explosions many lives have been saved by its use that almost certainly would have been lost otherwise, yet more than two thirds of the yearly production of bituminous coal from underground mines in the United States is still being obtained from mines that do not use rock-dust, and more than two thirds of all men that work underground in bituminous mines are employed in nonrock-dusted mines. These facts are revealed by a statistical survey of all mines in the United States that were in operation during 1930, 1931, and 1932. The survey was conducted by the Demographical Division of the Health and Safety Branch of the United States Bureau of Mines and was based upon reports from operating companies received in connection with the Bureau's annual statistical surveys of accidents in the mining industry.In 1932, the latest year for which complete figures are available, rock-dust was used, to some extent at least, in 393 bituminous-coal mines whose total production of coal during the year was 83,632,327 tons, or 30.6 percent of the entire output of bituminous coal from all mines in the United States not including opencut mines. The number of men employed underground at mines that used rock-dust was 25.7 percent of the total number employed underground at all bituminous mines, and the number of man-hours worked at these mines was 27.1 percent of the total number of man-hours worked underground at all bituminous mines during the year."

Nov 1, 1934

By Alex Rown

"THE SYDNEY COAL FIELD has long been afflicted by high costs and low productivities. However, a distinct possibility now exists that improvements can be made in costs, productivities and revenues. If these hopes materialize, the Sydney coal field will once again be regarded as a valuable asset in our national inventory of energy and metallurgical coals. The economic possibilities for the Sydney collieries depend on performance at the pits and in the market place. Because this audience is already well informed about colliery planning, I would like to start with an assessment of the modern coal market insofar as it may relate to the Sydney field. Since 1950 we have seen a vast growth in the population and industrial empires of the western world which has resulted in an enormous and escalating demand for energy. If the energy supply pattern of the first 50 years of this century had been followed, this would have led to an immense demand for coal."

Jan 1, 1972