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By J. R. Kadambi, E. Kucukal, J. Furlan

"Hydrocyclone separators are used in various industrial applications, including mining milling and tailings systems, in order to separate or classify solid particles and liquid droplets from multiphase systems. The flow within a hydrocyclone commonly used in the mineral processing industry was investigated numerically and experimentally using Particle Image Velocimetry (PIV) and refractive index matching techniques. The computational simulations were performed using a commercially available CFD package, STAR CCM+. Two turbulence models were used in the numerical calculations: the k-? model and the Reynolds Stress Model (RSM). In both cases, the first order discretization scheme was unable to resolve the flow characteristics accurately due to the high levels of numerical dissipation. PIV measurements were taken at various spatial locations along the cyclone. Both the numerical simulations and PIV data demonstrate that tangential velocities tend to increase when going radially inward from the cyclone wall towards the vortex finder, and reach a maximum value before they begin to decline rapidly and eventually become zero at the wall. The results also demonstrate the utility of non-axisymmetric approaches in cyclone flow simulations for a greater understanding of the fluid mechanics. The computational results were validated globally using pressure and flow rate readings at the boundaries and locally by comparison to the PIV velocity vector maps and profiles. The comparisons demonstrated good agreement between the two models.IntroductionHydrocyclones are devices used to separate and classify solid particles or liquid droplets from liquid-solid or liquid-liquid systems. Versatile in application, they have been widely used in many industrial applications including the food, oil, power generation, chemical and mineral processing industries since 1891, when the first hydrocyclone was introduced by Bretney (Park, 2003). Hydrocyclones have a relatively simple design with no moving parts, which leads to an efficient separation process."

Jan 1, 2016

By M. C. Villeneuve, P. A. Siratovich

We present an integrated analysis of laboratory-based thermally induced fracturing and results of numerical models to give insight to the role of thermal shock fracture on geothermal reservoir rocks. Thermal stimulation is a reservoir permeability enhancement technique applied to commercial geothermal reservoir rocks to enhance fluid injection capabilities for spent power plant working fluids. The process is well known to enhance permeability but the thermodynamic and physical constraints of the process are less certain. In an attempt to constrain the interaction and the ideal conditions that lead to permeability enhancement, experimental procedures were carried out to mimic the conditions that a reservoir rock would experience during a thermal stimulation using temperature differentials ranging from 50-300°C. Samples underwent such thermal gradients under controlled laboratory conditions and were characterized for the changes to permeability, porosity, ultrasonic velocities, dynamic elastic moduli and petrological changes. The thermal stimulation was simulated in a FLAC2D thermal numerical model to investigate the nature of the thermally induced changes in the sample. The development of this model also allows us to investigate the relationship between geological characteristics and the ability to thermally stimulate any type of rock. The results indicate that numerical thermal shocking experiments are corroborated by laboratory-based results. The implication of this study is that the refined numerical models present an insight to the conditions and constraints under which thermal stimulation can prove to enhance permeability that could not be gained through purely laboratory-based studies.

Jan 1, 2015

By Y. Jiang, B. Li, R. Liu

"In this study, laboratory flow tests were conducted on 2-D artificial rock fracture network models containing a single intersection constituted by two inlet and two outlet branches. Three models with different intersecting angles of 60°, 90° and 120° were tested using both dye solution and distilled water. Constant flow rates were imposed on one inlet, and the flow patterns in the fracture intersections were captured by using a CCD camera. The test results were compared with the predictions made by numerical simulations that solved the Navier-Stokes equations. The results revealed that when Reynolds number (Re) is as low as less than 1, the intersecting angle has negligible influence on the flow rate of each branch and the flow patterns within a fracture intersection. As the interesting angle ? and Re (e.g., from 10 to 200) change, the normalized flow rates of different outlet branches change significantly, due to the inertial effect of fluid flow. These changes could be represented by a series of mathematical expressions involving Re and ?, which could be applied to fracture network models to improve their prediction accuracy on hydraulic properties (e.g., permeability and breakthrough curves of particles) of rock masses. INTRODUCTIONCoupled stress, flow, heat and mass transport are the corner stone subjects for many geoscience and geo-engineering disciplines, such as geological disposal of radioactive waste and geothermal energy exploitation. Many outstanding issues need to be investigated to enhance the knowledge on these subjects, and specifically more in-depth research in testing and modeling of the fluid flow in fractured rock masses is needed. In recent years, discrete fracture network (DFN) models have been extensively used to study the fluid flow and mass transport behaviors of fractured rock masses (e.g., Min et al., 2004; Zhao et al., 2011). In these models, each fracture is usually represented by a parallel-plate model, in which fluid flow exactly follows the cubic law. Therefore, comparative flow rate in each outlet branch of an intersection in these models only depends on its aperture. In reality, due to the surface roughness of fractures, the magnitude of mechanical aperture is usually larger than that of the hydraulic aperture of each fracture (Li et al., 2008; Xiong et al., 2011), and abundant flow patterns could exist in an intersection, influenced by its geometry, varying with changing Reynolds number (Re) (Kosakoswski & Berkowitz, 1999). Recent studies have also revealed that different mixing patterns might exist at a fracture intersection, bounded between streamline routing model and complete mixing model, that determine the final distribution of solutes in fractured rock masses (Johnson and Brown, 2001; Park et al., 2001). Numerical simulation has been the principal method adopted in previous studies, and the studies conducting flow tests on intersected fractures are less reported (Wilson & Witherspoon, 1976; Johnson and Brown, 2001). In this study, laboratory flow tests and numerical simulations by solving the Navier-Stokes equations were conducted on 2-D models containing a single intersection constituted by two inlet and two outlet branches, intersected at different angles. The main objective is to study the influence of intersecting angle on the flow behavior of the intersected fractures and the variations of flow patterns and fluid redistribution in each model along with the changes of the Re and the intersecting angle ?. The influence of surface roughness was not considered."

Jan 1, 2015

Resistance spot welding is the most common type of welding in the automotive industry. In RSW the size and shape of welding nugget is one of the most effective factors on mechanical properties, such as tensile shear strength and fatigue strength. so properly adjusting the variables of the welding is necessary .in this study the effect of different parameters of RSW including time, current, electrode force, geometry of electrode so diameter and angle of electrode tip in the shape and size of welding nugget evaluated. for experimental procedure, low carbon steel sheet st12 is used. the process is simulated with finite element method by using ANSYS software. for the formation of welding nugget a 2 dimensional symmetrical model electrical-thermalmechanical is used and for elevate the accuracy ,we determined the properties of material related to temperature. The results show that increasing the time and current of welding, the diameter of spot weld also increased and the role of current is more impressive. and also increasing the electrode force decrease the diameter of the nugget due to increasing the contact area and decreasing the resistance .increasing the diameter of electrode tip cause increasing contact area and decreasing the resistance and decreasing the diameter of the nugget. furthermore, changing tip angle and electrode diameter don't show sensible change in the geometry of the welding nugget. comparison between simulation and experimental result show a good adaption.

Oct 1, 2011

By T. Hidayat, D. Shishin, S. Sineva, M. Shevchenko

The effects of the slagging components Al2O3, CaO and MgO on the thermodynamics and phase equilibria of the gas/slag/matte system with major elements “Cu2O”-“FeO”-SiO2-S are characterised using an integrated experimental and thermodynamic modelling approach. The experimental technique included high-temperature equilibration experiments using a spinel substrate in controlled gas atmosphere (CO/CO2/SO2/Ar), quenching of the sample and subsequent measurement of the compositions of equilibrium phases with Electron Probe X-ray Microanalysis (EPMA). Thermodynamic modelling is undertaken using the computer system FactSage. In previous experimental studies on this system, the separate effects of Al2O3, CaO and MgO were determined. In the present investigation, the combined effects of these additional components are investigated at 1200oC and P(SO2) = 0.25 atm and a range of P(O2)’s. Special attention is paid to ensuring chemical equilibrium is achieved in each case, for this reason possible kinetic factors are systematically analysed. The results obtained are presented in the form of graphs showing the compositions of matte and slag phases as functions of copper concentration (matte grade). The new experimental data are used for the improvement of the thermodynamic database for multicomponent copper-containing systems. The effects of the slagging elements on this multicomponent system will be presented in the paper. INTRODUCTION Whilst Fe-O-Si form the principal components of copper smelting and refining slags, additional impurities are present in industrial practice typically at 2–5 wt.% Al2O3, 1–4 wt.% CaO and 1–2 wt.% MgO levels (Davenport, King, Schlesinger, & Biswas, 2002). These elements are introduced into the slag as impurities in concentrates and other feedstocks, in fluxes added to the process and in refractory materials. Understanding, and accurate description, of the changes that take place in the smelting process in the presence of these additional elements is of major importance to the optimization of industrial operations. Although experimental data are available on slag/copper matte equilibria, further work is needed to accurately characterise the influence of Al2O3, CaO and MgO on phase equilibria and elemental distributions of elements in gas/slag/matte systems. The individual effects of the Al2O3, CaO and MgO slagging components on equilibrium phase assemblages under selected conditions have been quantified in a recent series of studies on the Cu–Fe–O–S–Si-(Al, Ca, Mg) gas-slag-matte-metal system (Fallah- Mehrjardi, Hayes, & Jak, 2018; Fallah-Mehrjardi, Hidayat, Hayes, & Jak, 2017a, 2017b; Hidayat, Fallah-Mehrjardi, Hayes, & Jak, 2018a, 2018b; Jak et al., 2016; D. Shishin, Decterov, & Jak, 2018; Denis Shishin, Hayes, & Jak, 2018). Since, thermodynamically, the condensed phases do not behave ideally, it is to be expected that the effects of individual elements may not be additive, and the additional interactions between the Al2O3, CaO and MgO slagging components will also have to be taken into account. These additional effects are expected to be smaller than those of the individual components, so higher accuracy is needed. The present paper describes analysis of the precision and accuracy of the experimental technique on multi-component, multi-phase equilibria in these systems to enable the combined effects of Al2O3 + CaO + MgO on slag/matte/spinel equilibria, i.e. for high Fe/SiO2, to be accurately measured. The effects of Al2O3, CaO and MgO on the gas - slag - matte are analysed using a thermodynamic modelling approach with the computer package FactSage.

Jan 1, 2019

By Yu Chen, Charlie C. Li

The application of rock bolts for the stabilisation of underground openings needs a good understanding of the response of the bolts during rock excavation. The pull-and-shear performance of two types of rock bolts—that is, the fully encapsulated rebar and the D-Bolt—has been studied both experimentally and numerically. The rock bolts were tested under a pull-and-shear load at five displacing angles (i.e., 0°, 20°, 40°, 60°, and 90°), and at the same time, the strains on the bolts were monitored during testing. The two types of rock bolts have similar loading capacities, while the loading angle has obvious influence on the deformation capacity of the D-Bolt. The ultimate total displacement of the D-Bolt decreases from 140 mm under pure pull loading to 70 mm under shearing. The displacement capacity of the rebar is not significantly influenced by the loading angle but remains at a quite low level from 29 to 53 mm. The D-Bolt yielded in a longer section the rebar bolt under pure shear. A trilinear material model was used to simulate the strain hardening behaviour of the bolt steels in the numerical code FLAC3D. The numerical results show that the axial load in the bolt decreases exponentially with the distance from the loading position for the rebar bolts, but it remains constant in the bolt sections between the anchor positions for the D-Bolts. When the bolt is subjected to a lateral load, shear stresses are created on the D-Bolt surface within a short distance from the loading position.

Jan 1, 2015

By Y. Champoux, N. Atalla, R. Oddo, C. Lesage

"Percussion drills are the source of the most serious noise problems in mining activities, due to their extremely high noise levels(114-122 dB(A)) and widespread use(Bartholomae and Stein, 1988). Percussion drills will continue to be widely used to drill small diameter holes in hard rock because no other method seems to be economically avail-able to replace them (Boillat et al., 1993).Many studies (Danière, 1991; Hawkes etal., 1977a; Jensen and Visnapuu, 1972;Leblond et al., 1976; Milette, 1989) were con-ducted to determine the major noise sources of percussion drills. The exhaust air of pneumatic drills, the hammer, the bit in contact with the rock and the drill rod have been identified as the major noise sources. A muffer can be used to reduce the exhaust noise and the hammer can be enclosed. The bit noise is considered to be of concern only at the beginning of holes. When all the available methods are used to reduce the noise of a percussion drill, the drill rod vibrations become the dominant noise source (Hawkes and Burks, 1979). However, the noise levels generated by this source remain high and future efforts should concentrate on reducing its radiation.Works by Hawkes and Burks (1979) and Hawkes et al. (1977b) for the U.S. Bureau of Mines provide the most complete description on the noise and vibration of percussion drill rods.The longitudinal and bending waves are the two most important types of elastic waves generated in drill rods. Among these, only the longitudinal waves contribute to the drilling rate. The bending waves are caused by non-centralized impacts, drill rod curvature and non-uniform bit/rock interface. Drill rod noise is generated by Poisson’s ratio expansions and contractions of the rod as the longitudinal waves travel up and down it and by transverse rod motions induced by bending waves. The radiation efficiency is much higher for bending waves than for longitudinal waves. Most of the impact energy is transformed into longitudinal waves, as expected for axial impacts. The evaluation of the relative contribution of longitudinal and bending waves to noise generation poses a very difficult problem for experimental, analytical and numerical approaches. It is, however, an important issue because the relative contribution of these two waves will guide future noise reduction efforts. It seems that very little can be done to reduce the noise radiation of the axial waves without affecting the drilling rate. The main difficulty that analytical and numerical approach-es face, in the evaluation of the relative contribution of the two waves, is that there is no adequate theory for predicting the bending vibrations from the factors that cause them. The experimental approach has, thus, been limited to test fixtures that do not adequately represent the boundary conditions, as well as by measurements obtained under real operating conditions from which it is difficult to establish the relative contribution of the two types of waves. For example, Hawkes and Burks (1979) and Hawkes et al. (1977b) used a test fixture with free-free boundary conditions and made no clear link with measurement under real operating conditions. Rather, they have based their discussion on a simple model. Many authors assume that fexural waves are the main noise source on drill rods. However, measurements have been somewhat contradictory and researchers are still unable to state with certainty that this is indeed the case (Lednik et al., 1988)."

Jan 1, 1997

By Y. Zedan

In this study, the statistical design of experiments (DOE) was applied to study and regulate the properties of near-eutectic Al-11%Si alloys. Develop regression equations for such response variables as hardness, yield stress, ultimate tensile stress, percent elongation, total cutting force, cutting power, and tool life together with other factors which, include the percentage composition of the alloying elements, and the requisite modification (Sr) level. These equations may be analyzed quantitatively to acquire an understating of the effects which the main variables and their interactions may have on the mechanical behaviour and the machinability of the alloy under investigation. The results reveal that increasing the levels of Cu and Fe content results in an increase in hardness, yield stress, and ultimate tensile strength in both modified and non-modified alloys. On the other hand, both Cu and Fe appear to affect the percentage elongation adversely, whereas the Sr-level has a positive effect on this parameter. It was found that Sr-levels have the most significant effect on the cutting forces and cutting power followed by the content in Fe and Cu. The results also reveal that the interaction coefficients of these variables have a significant effect on tool life compared to the main independent variables. This fact may be attributed to the formation of complex insoluble phases between Cu, Fe, Si, and Al as investigated using Scanning Electron Microscopy (SEM) attached to an EDX analysis system. The accuracy of the regression equations in predicting the expected properties has been verified by carrying out random experiments in the range of variation of these variables.

Jan 1, 2011

By R. A. Campbell

The electric smelting of five lowgrade Canadian manganese ores has been investigated at the Mines Branch, Department of Mines and Technical Surveys, Ottawa. Ferromanganese, silkomanganese, and spiegeleisen were produced 1by special smelting processes from these ores since the latter were too low grade to be treated by conventional smelting methods. In one case the results were considered to be sufficiently promising to justify the construction of a pilot plant, by the Company concerned, for the further development of the process.

Jan 1, 1956

By R. A. Campbell

Pig iron and silicospiegeleisen were produced experimentally from a very low-grade manganiferous iron ore from Steep Rock, Ontario, by a two-stage electric smelting process. The most favourruble operating conditions were determined for each stage. Cement clinker then was made by calcining the slag from the second stage of smelting, with additional limestone and alumina. (This slag would normally be a waste material). The cement clinker produced had the composition of commercial Portland cement, and met the physical test requirements of the Canadian Standards Association Specification A5-1951 for normal Portland cement as well as could be expected for a material produced on .such a small scale.

Jan 1, 1958

By G. E. Veins

A three-phase, continuously-operated, 250 kv.a. electric smelting furnace has been installed at the Mines Branch, Department of Mines and Technical Surveys, Ottawa, for the experimental treatment of ores and by-products of interest to the Canadian mining, metallurgical, and chemical industries. In the operation of this furnace particular emphasis is placed on the accumulation of quantitative data which will be useful in determining the most suitable smelting technique and the nature of the products, and in arriving at preliminary conclusions regarding the cast of power and electrodes. The results obtained in the experimental smelting of iron, manganese-iron, titanium- iron, nickel, and chromiumiron ores, and of a number of industrial by-products, clearly show the value of such treatment for materials of this type.

Jan 1, 1957

By G. E. Veins

This paper summarizes an investigation in which beneficiated ilmenite ore was smelted in a continuous, three-phase, 250 kv.a., open-top electric furnace. Minus %. inch ore was smelted, using the standard method. Fine ore, in the order of minus 14 mesh, was smelted in the briquetted form by the open bath method, and in the unagglomerated form by the cold dry-top method. The latter was shown to be superior. The data obtained .are discussed at some length. During the investigation, slag aver-aging 82.5 per cent Ti02 was produced over a period of 87 hours, the maximum being 85 per cent. Such slag should .be particularly attractive for the production of titanium tetrachloride, from which titaniurn metal is produced. The advantages of using paper-mill bark for producing a furnace charge of low bulk density, as required in cold dry-top smelting, were emphasized.

Jan 1, 1957

By R. Stauber, B. Friedrich, S. Hilgendorf, G. Homm, C. Gellermann

Due to recent regulations limiting tolerated lead concentrations in copper alloys, new recycling strategies have to be considered. This study investigates the suitability of technical approaches in order to recycle leaded copper alloys exemplified by CuZn39Pb2 and produce an alloy in compliance with future lead regulations in the European Union. Three pyrometallurgical methods are considered to achieve this goal, namely vacuum distillation, intermetallic precipitation and fractional crystallisation. The impact of essential process parameters i.e. pressure, temperature, time, atmosphere and quantity of additives are identified using thermochemical and kinetic modelling. An experimental implementation reveals a general suitability of all three refining processes. However, the individual efficiency of the different methods strongly differs. Thus, a detailed assessment is carried out in order to provide an evaluation on the efficiencies of these methods from a technological, economical and environmental point of view. Taking a possible industrial realisation into account, the authors recommend the approach of vacuum distillation, although the energy demanded is comparatively high due to the enthalpy of evaporation for zinc, or rather, lead. However, required lead concentrations can be reached quickly without introducing an external element to the material. The prediction of selectivity and evaporation speed, which are immanent variables for a successful implementation, can be validated experimentally. INTRODUCTION In 2016 approximately 1 million tonnes of leaded copper alloy semi-finished goods with an average lead content of 2.1 Ma% have been produced in the European Union (EU). The global production in the same period exceeded 5.5 million tonnes, while the lead concentration has stayed constant at around 2.4 Ma% for the last 50 years. Up to 80 % of the current production volume is covered with end-of-life scraps, which are used for direct re-melting, depending on the alloy composition. Lead has been a popular alloying element in copper alloys in general, and in particular in brass due to its positive impact on various mechanical, physical and chemical properties, especially machinability. Health and environmental concerns were drivers for many governments to implement limitations on lead. In order to further utilise the resource potential of leaded copper scrap, it is inevitable to develop methods to efficiently eliminate lead from circulation as far as possible. (Glöser, Soulier, & Tercero Espinoza, 2013; Soulier, Glöser-Chahoud, Goldmann & Tercero Espinoza, 2018)

Jan 1, 2019

By J. Dionne

"Next to the actual mine of Les Explorations Muscocho Ltée in Montauban, Quebéc, you could find a total of 364 000 tons of flotation tailings assaying 1.4 Au g/t et 82 g Ag/t to the south of the municipality. This tailings pile is what is left of previous operations. Preliminary leaching tests on these tailings in laboratory columns gave interesting results which led to tests in larger columns in 1984 and to a pilot test on a 750 ton heap in Montauban during the summer of 1985.This paper briefly describes the columns tests performed at the Centre de Recherches minérales and the heap leaching test designed and conducted by SOQUEM in Montauban. It also presents the results obtained.RESUMEPrès de la mine actuelle de Les Explorations Muscocho Ltée à Montauban, Quebéc, se trouvent, au pied du village, 364 000 tonnes de rejets de flottation titrant environ 1,4 g Au/t et 82 g Ag/t. Ce tonnage de rejets représente ce qui reste de l'opération des anciennes mines de Montauban.Des essais préliminaires de lixiviation en colonne sur ces rejets ont donné des résultats encourageants. Ils ont été suivis en 1984 par des essais en colonnes plus volumineuses et par un essai pilote à Montauban en 1985 sur une pile de rejets de 750 tonnes.Ce te x te donne une brève de script ion des essais en colonne effectues au Centre de Recherches minérales et de l’essai pilote planifie et exécute à Montauban par SOQUEM. Il présente les résultats obtenus."

Jan 1, 1987

By Y. S. Sun, Northeastern University, W. B. Li, P. Gao, Z. Y. Zhang, J. W. Yu

"The boron-bearing iron concentrate was extracted from ludwigite ore by the process of magnetic-gravity separation. In order to fully utilize the refractory ore and meet the boron consumption of China, a novel process for separation of boron from iron in boron-bearing iron concentrate was proposed in this paper. In particular, laboratory scale experiments of improving boron reactivity were performed. Fine boron-bearing iron concentrate briquettes were reduced by bituminous coal completely at 1125 °C for 150 min. The effect of sodium carbonate, which was used as an additive in the roasting process, was investigated. The addition of sodium carbonate decreased the boron reactivity and facilitated the volatilization of boron. The influence of diverse cooling methods of the reduced samples on the boron reactivity was studied. The results indicated that boron reactivity could reach up to 80.76% when the reduced samples were cooled by rapid water quenching. In addition, the magnetic material containing 92.71 % Fe with a recovery of 95.11 % and boron-rich non-magnetic material containing 14.51% B2O3 with a recovery 88.85% could be obtained by low-intensity magnetic separation. The magnetic material and boron-rich non-magnetic material were good raw materials for steel-making and borax production, respectively.INTRODUCTION Ludwigite ore is abundant in Liaoning province of China, with 28.43 Mt B2O3 accounting for 57% of the boron resources of the country (Liu et al., 2006). However, it has not yet been utilized on an industrial scale due to its complex mineralogy and fine mineral dissemination (Wang, Wang, Ding, Ma & Xue, 2012). At present, boron-bearing iron concentrate and boron concentrate can be obtained from ludwigite ore using magnetic-gravity separation. The boron concentrate contains B2O3 12%~16%, which can be used as a high-quality raw material for the boron chemical industry after activated roasting, but the B2O3 content in the iron concentrate reaches up to 4%~6%. In order to further separate boron and iron from boron-bearing iron concentrate, a blast furnace and a solid pre-reduction followed by electric arc furnace melting have been proposed (Liu, Cui & Zhang, 1998; Wang et al., 2012). However, both of these two current routes face the same crucial problem that molten boron-rich slag has to be cooled slowly to obtain the alkali-dissolution activity of boron, which affects the yield of boron resource."

Jan 1, 2016

By R. Pelletier, Herny. E., C. Allaire

Corrosion of refractory linings by molten metals is controlled by interactions between penetration and chemical reaction. Corrosion of aluminosilicates by molten aluminium is no exception. The early stage of corrosion can be described as a particular case of reactive wetting over a porous medium. Although the reactivity between aluminium and silica is great, which should improve wetting and penetration, the presence of air and the formation of a protective oxide layer disfavours initial penetration. This paper presents the results of an exploratory study on the effect of some parameters on the initial stage of aluminium penetration. Penetration kinetics and metal intrusion tests have been performed on alumina and silica powders with pure aluminium and Al¬5%Mg. Capillary models are used as tools of interpretation. Penetration kinetics tests had a poor reproducibility and the kinetics itself can not be explained very well by the capillary-tube-bundle model. On the other hand, a capillary model initially developed for ice intrusion into freezing soils produced predictions in reasonably good agreement with intrusion pressure measurements. The effect of particle size and alloy composition can be predicted using this model. However, the effects of temperature and powder chemistry need additional interpretations to be rationalised. An unusual resistance to penetration of silica powder by molten aluminium have been observed in a series of experiments. This led the authors to the strange conclusion that oxygen should be seen as an excellent non-wetting agent and that there might be ways to use it in industrial applications.

Jan 1, 2004

By S. Nikolic, O. O. Kehinde-Philllps, O. T. Djamgouz, D. H. Rousell

"A bulk mining method is employed at the Lockerby mine resulting in the formation of large muck-piles. If these muckpiles remain in the stopes for some time they may agglomerate to the extent that the muck cannot be removed by a scooptram. A laboratory investigation was undertaken with sulphide material from the mine in order to detemine the time that oxidation begins and the flowability of the material as a f unction of several factors. The laboratory results are applied to the conditions in the muck-piles.The time of the beginning of oxidation of the material decreases as the sulphide composition, water content and availability of air increases. Oxidation is retarded by the addition of a copper sulphate solution instead of water. The unconfined yield force (strength} of the material increases with an increase in the sulphide composition, water content and time. The material ceases to be free-flowing before there is visible evidence of oxidation and this suggests that oxidation actually begins earlier and that agglomeration is also due to the capillary action of water.Broken ore should be removed from the stope prior to the time a muck-pile ceases to be free -flowing-perhaps as early as two days f or high-grade ore and 5 days f or low-grade ore. In order to control dust, 1.4 weight per cent of a 5 per cent solution of copper sulphate should be added 10 the muck-pile rather than water. This inhibits oxidation and increases the time that a muck-pile remains free-flowing."

Jan 1, 1984

By Ki-Bok Min, Seokwon Jeon, Seung-Beum Choi, Taehyun Kim

"In order to investigate anisotropic characteristics of Boryeong shale in Korea, which clearly shows transverse isotropy, a series of experimental tests were carried out. Using Brazilian test, five elastic constants and tensile strength of the shale were evaluated. Elastic constants were determined by iterative procedure and in order to perform this procedure, constitutive model was modified to fit the experimental condition. The anisotropic ratios of elastic constants were evaluated and the applicability of the methodology was assessed. Apparent Brazilian tensile strength profile was investigated and the ratio of the maximum to minimum tensile strength was estimated. Results showed that the tested rock type had low to moderate anisotropic characteristics.INTRODUCTIONMechanical, thermal and hydraulic characteristics of many rocks vary according to direction, which is known as inherent anisotropy, and it is originated from stratified and/or foliated structure of intact rock and discontinuity of rock mass. Anisotropy is one of the long standing issues of rock mechanics field and it has to be taken into account in several engineering fields such as civil, mining and petroleum engineering. An anisotropic medium has 21 independent elastic constants without any assumption of symmetry. If a material has any symmetry, the number of elastic constants required to define its behavior reduces and eventually two constants are necessary if it has complete symmetry, which is known as isotropy. An anisotropic medium that has remarkable planar structure due to its stratification and foliation such as bedding is often called as a transversely isotropic medium. Transversely isotropic model is frequently adopted in many applications especially for sedimentary rock formation and five elastic constants are required to establish the constitutive model."

Jan 1, 2015

By Botao Lin, Yan Jin, Hongjuan You, Jingjun Pan, Huiwen Pang, Mian Chen, Sen Chen

"Steam Assisted Gravity Drainage (SAGD) has become the mainstream technology for ultra-heavy oil recovery in Xinjiang oilfield, the success of which depends heavily on shortening of preheating period as well as forming homogeneous and highly permeable zone in land-facies oilsands layer. Towards this aim a special hydraulic fracturing process is required, which is accomplished through controlled water injection to a pair of horizontal wells in order to create homogenously distributed microcracks in the zone between the two wells. The associated mechanical response, however, is unclear for land-facies Karamay oilsands that is loose in texture. In this regard, this research utilizes a triaxial test system on cylindrical specimens extracted from field-collected oilsands cores. Isotropically consolidated drained triaxial compression tests are conducted on both saturated and unsaturated specimens so as to investigate the mechanical response of oilsands at different spots relative to the wellbore. Moreover, acoustic emission and fast pulse-decay permeability are performed to monitor fracture development and permeability evolution. Based on these experimental studies, the mechanism of dilation in oilsands is comprehensively analyzed. The findings reveal distinctive behavior between the saturated and unsaturated specimens as respect to dilation, porosity/volumetric evolution and change of permeability. It is also found that shear bands can be created upon shearing on triaxial specimens, rendering porosity or volumetric strain the factor that is more proper for evaluation of stimulation efficiency in the field.INTRODUCTIONXinjiang oilfield is widely known for its abundant deposit of heavy and ultra-heavy oil that has been estimated to be several hundred million tons. The ultra-heavy oil deposit located in Fengcheng region of Karamay at the northwestern part of the Junggar Basin, Xinjiang, China, has over 360 million tons of resource (Yuan et al. 2013). The resource is deposited in depths from 180 to 450 m and has viscosity over 100, 000 mPa•s at a temperature of 50ºC, bringing technical challenges to recovery activities."

Jan 1, 2015

By T. Hidayat

The distributions of minor elements between slag/metal and slag/matte in equilibrium with tridymite in the Cu-Fe-O-S-Si-Al-Ca system have been investigated in the range of conditions of interest to the high- temperature copper production, refining, and recycling processes. An improved experimental methodology has been used involving high temperature equilibration in controlled gas atmospheres, rapid quenching, and quantitative microanalysis techniques using Electron Probe X-ray Microanalysis (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrum (LAICPMS). The effect of oxygen partial pressure on the distributions of minor elements between slag/metal and slag/matte has been accurately measured. The effects of slagging components (Al2O3 and CaO) on the distributions of minor elements between slag/metal have also been experimentally determined. The present study is a part of a larger integrated experimental and thermodynamic modelling research program in the systems relevant to high-temperature copper processing. INTRODUCTION In the high temperature processing of copper, minor elements are distributed between different phases, i.e. liquid slag, liquid matte, and liquid metal. From a processing perspective, it is desired to have the valuable minor elements distribute predominantly in the metal and matte phases rather than in the slag phase, and to have the non-valuable minor elements distribute predominantly in the slag phase rather than in the metal and matte phases. Knowledge of the distributions of minor elements between phases in the smelting, converting, and refining processes is required if the distributions of minor elements between phases in these processes are to be optimized.

Jan 1, 2019