Search Documents

By David Eichenberg

A154S A154N After 3 Years of Mining ?Current mining Level A154S 280RL ?110 Vertical metres of A154S ?Current mining Level A154N 300RL ?100 Vertical metres of A154N ?Variations in Kimberlite Volume ?Ore Types and Plant Production

May 1, 2006

By Stephen D. Butt

Presentation Outline Overview of abandoned mine workings problem. Outline project phases and major outcomes. ? Phase 1 ? Assessment of current imaging technology ? Phase 2 ? Prototype technology development. ? Phase 3 ? Proof of concept ? Montague Gold Mines field trials. Research status - summary of ongoing and future work.

Apr 1, 2005

By A. A. Lavrinenko, N. I. Gluhova, L. M. Sarkisova, D. V. Makarov

"The investigated sulfide Cu-Ni ores are characterized by low PGE contents and emulgated impregnations of pentlandite and palladium minerals in the main ore-forming mineral pyrrhotite, which hinders their selective separation, requiring a collective flotation of sulfides to concentrate, and hydrometallurgical processing. As revealed by studies of floatability of Pt-Cu-Ni ore in a mixture of butyl xanthate and chelating phosphorus containing reagents, the most effective additive is Aerophine 3416 (a phosphinates mixture) manufactured by Cytec. Using collective flotation with a butyl xanthate – Aerophine 3416 composite in the ratio of 1:3 has afforded to enhance the Pt, Pd, and Ni recovery by 13.6 %, 9.2 %, and 9.4 %, respectively. The optimal ratios of Aerophine 3416 to butyl collector for the collective flotation are the following: 1:1 for Pt and Pd and 3:1 for Ni. The effect of these reagents on the electrode potential and surface hydrophobicity of pyrrhotite, pentlandite, and platinum black has been investigated. The extraction UV spectrophotometry experiments demonstrate that DIBDTPI exists on the pyrrhotite surface mainly in the form of disulfide in weak acid medium and in the form of compounds with Fe on the mineral surface in minute amounts. There appears some disulfide and few amount of (DIBDTPI)2Ni on the surface after interaction of DIBDTPI and pentlanditeINTRODUCTIONXanthates are widely used in flotation of copper-nickel ores containing platinum group metals (PGM) as sulfides collectors which can concentrate the most part of PGM connected with the sulfides. Though xanthates are hardly efficient for flotation of free PGM, the latter are floated more slowly compared to the sulfides of base metals. The reasons for poor floatation of free (mineral) forms of PGM are under-researched, however the key accepted reasons are: fine disseminations of free PGM, insufficient interaction with xanthate and negative influence of blue copperas and sulfur-containing ions which are sulfides oxidation products (Penberthy et al. 1999; Shackleton et al., 2007). That’s why an additional collector, normally dialkyldithiophosphates, is used during flotation of PGM-containing copper-nickel ores. A reagent DP-4 is used for recovery of PGM at Norilsk mining and metallurgical plant. The reagent represents a slightly-soluble organic calcium sulfonate which is given to flotation pulp in the form of water emulsion of 5% - solution in automotive diesel oil."

Jan 1, 2016

By E. Poiate, P. A. L. P. Firme, D. Roehl, M. A. Carrion, A. M. Costa

Drilling high-pressure/high-temperature wells in salt rock formations is still a challenge for the energy industry. Creep and solubility is part of the salt rock physical-chemical behaviour, which must be considered in the design of the wells. The stress redistribution caused by drilling, in addition to thermallyactivated processes, triggers creep deformation, leading to borehole closure and the imposition of loads on the casing. The drilling fluid is designed by computer modeling in order to control the creep strain rate to a limit which allows the drilling operations and the casing setting. Depending upon the composition of the drilling fluid, chemical reactions on the salt wall may occur, especially in case of water-based fluids in highly soluble salt rocks. In those cases, cavities by dissolution (washouts) can be generated and the casing column remains uncovered by the cementation and laterally unconfined along the cavity length. This scenario is propitious to the loss of integrity of the casing due to phenomena such as plastic collapse, buckling and non-uniform loading on the casing provoked by the closure of salt formation around it. The casing should remain intact during the wellbore life-time. In this work, a section of a typical well crossing salt formation composed by halite and carnallite is considered. An idealized-cylindrical washout cavity inside a highly soluble salt layer is assumed. The purpose here is to evaluate the effect of the dimensions of the cavity on the integrity of the casing. Several typical diameters and lengths of the cavity are adopted. Numerical analyses are carried out with an in-house finite-element system composed by the pre-processor MTOOL 3D®, the simulator ANVEC 3D® and the post-processor POS 3D®. Salt rocks are modeled as visco-elastic materials. Creep is simulated by the Double Mechanism Creep Law, widely employed in Brazilian salt rock mechanics research. Cement and casing (steel) are modeled as elasto-plastic materials described by the Mohr-Coulomb and the von Mises criteria, respectively. Casing integrity is evaluated with respect to vertical and horizontal displacements. Vertical displacements imposed to the casing can provoke the failure of the column by plastic collapse or by buckling. Besides that, horizontal displacements of salt due to creep closure shall lead to the undesirable contact with the casing. Failure envelopes based on displacements are generated. The results of the simulations have shown that the casing failure by plastic collapse occurs preferentially in short columns, as well as buckling occurs in long and slender columns. The occurrence of both failure modes is more frequent in large-diameter cavities. Additionally, failure caused by contact between salt and casing occurs preferentially in short-diameter cavities.

Jan 1, 2015

By Yujing Jiang, Xuezhen Wu, Bo Li, Tomomi Iura, Gang Wang

"Yielding bolt has been widely used for rock reinforcement in mining and civil engineering in high stress conditions. However, the interaction mechanism of yielding bolt and matrix mass is still not clear at present, and no analytical model is available to predict its reinforcement effect quantitatively. In this paper, the mainstream yielding rock bolts were reviewed firstly. After that, a coupling model is proposed to account for the interaction between yielding bolt and matrix mass. Based on the plane strain axial symmetry assumption and the incremental theory of plasticity, equilibrium equations and compatibility equations of matrix mass, and also the response of yielding rock bolt are deduced theoretically. The proposed method was programmed in Visual Basic development environment, and a semi-analytical solution for the coupling model is achieved. The reinforcement mechanism of yielding bolt in conventional tunnelling is clearly demonstrated through an illustrative case study. The reinforcement effect of yielding bolt is estimated quantitatively, and the distribution of axial force along the bolt is presented. In addition, the validity of proposed method is verified by numerical simulations. INTRODUCTIONHigh stress in surrounding rock mass can cause serious stability problems such as massive squeezing in soft rock and rock burst in hard rock. It is observed that many conventional rock bolts failed when experiencing large displacement, which implies that they are too stiff to sustain large deformation and dynamic conditions (Stillborg, 1994; Hoek et al., 1995). Yielding bolt, which can also be called energy-absorbing bolt, has been widely used for rock reinforcement in mining and civil engineering for these conditions (Neugebauer, E., 2008). This paper focuses on the static reinforcement effects of the yielding bolts with analytical method and numerical simulations."

Jan 1, 2015

By Pura Alfonso, Teresa Escobet, Hernan Anticoi, Eduard Guasch, Josep Oliva, Sarbast A. Hamid

"The liberation modelling of mineral particles using mineral liberation analysis have been used in the past to model comminution and concentration processes. In this work this concept has been taken a little further, using comminution and concentration for applying the mineralogical characteristics of particles. This approach is shown using the image analysis, mineral liberation analysis and the distribution density functions for liberation modelling. The work focused on the effect of comminution on mineral liberation for liberation modelling. To model this, effect the mineral liberation of the particles using distribution density and the cumulative distribution was linked to the image analysis of the ore particles. These properties have been estimated by statistical measures such as the distribution density and liberation grade, which were extracted from MLA data and images analysis, using proper image analysis and techniques based on MATLAB software. A comparison of different tungsten ores of liberated particles, has been introduced and evaluated by estimated results and image analysis.INTRODUCTION The chief economic minerals of tungsten are wolframite [(Fe,Mn) WO4] and scheelite(CaWO4), and approximately two-thirds of the world tungsten reserves consist of scheelite deposits (Lassner and Schubert, 1999). Tungsten has unique properties and is widely used in various industrial high strength and high temperature applications. It occurs coarsely aggregated in low grade ores. Most of tungsten ores, particularly scheelite, wolframite and ferberite, occur in deposits with very low content of WO3 (0.1–2.5%) that is not economically viable to apply directly metallurgical methods to extract tungsten (Martins, 2014). Tungsten is considered as a critical metal by the European Union by the economic importance and also the high supply risk (European Commission, 2014; Chakhmouradian et al., 2015).Currently, scheelite is playing an increasingly important role in tungsten industry because the mineral reserve of wolframite is getting depleted after gradual exploitation and utilization (Min et al., 2016). In mineral processing, the liberation of valuable mineral from the gangue determines the efficiency of subsequent separation processes. The liberation characteristics of an ore are primarily dependent on its texture, the association of mineral in the host matrix of gangue minerals, and to some extent on the grinding process (Zhang and Subasinghe; 2013)."

Jan 1, 2017

By George Dogbe

Open pit optimization forms the basis of mine design, production planning and construction of mine facilities. The negative effects of this phase may include substantial reductions in ore recoveries, relocation of waste dumps and surface infrastructure, extraction of unwanted waste, with a cumulative effect on mine value reductions. As a result, this area has received significant research focus using linear and dynamic programming, heuristic, genetic and stimulation algorithms and the graph theory. These algorithms are derived from rigorous mathematical models, but they are built on the assumption that all the periodic production capacities are extracted at the time of analysis. This assumption weakens the models because mining occurs over significant time period. In order to develop a comprehensive model that accounts for the timing of material extraction, the current models, which are built on the economic block value (EBV) concept, must be modified to account for time. In this paper, the authors develop a model of the optimization problem using the 2-D Lerchs-Grossmann?s optimization algorithm. This model is used to investigate the effect of periodic discounting on the optimal pit layout design by designing an integrated pit optimiser (IPO) that incorporates ?production scheduling?. IPO uses the ensuing discounted economic block value (DEBV) as a basis for the pit optimisation process. The time-dependent model is compared with a time-independent model. The results show that discounting has no effect on the optimal pit contour although the reported pit value is overstated if the EBVs are used instead of the DEBV. The authors, however, believe that this conclusion may not be general and could have been influenced by the nature of ore body geometry and the proposed mining strategy.

May 1, 2004

By Li Qihou, Liu Zhihong, Liu Zhiyong, Yao Wei

Black copper sludge, which mainly contains copper, arsenic and a little antimony, bismuth, selenium, tellurium, is an important recyclable secondary resource. In this paper, selective removal of arsenic from black copper sludge by alkaline oxidative pressure leaching was studied. The influences of alkali concentration, leaching time, leaching temperature, oxygen pressure, liquid-solid ratio and other variables on the leaching rate of arsenic, copper and tellurium were investigated. The results were as follows: when the leaching process was conducted at initial alkali concentration of 1mol/L, liquid-solid ratio of 10, stirring rate of 500r/min, leaching temperature of 140°C for 5 h and oxygen pressure of 2.5MPa, the leaching rates of arsenic and tellurium were 85.43% and 59.7% respectively, and copper, antimony, bismuth were not leached. Hence, arsenic has been removed effectively from black copper sludge, while the valuable metals such as copper, antimony and bismuth remained in the residue that can be further recovered easily. INTRODUCTION Black copper sludge is a byproduct in the purification process of copper electrolyte. Arsenic, antimony and bismuth are major harmful impurities in copper electrolytic refining system. The accumulation of these impurities will cause adverse effects, such as the increase of electrolyte resistance and power consumption and deterioration of cathode copper quality (Wang, Liu, & Zhang, 2001). Hence, electrolyte purification is an essential part of the electrolysis process (Liang, Chen, & Guo, 2009). Electrolyte purification methods include electrowinning (Davenport, King, Schlesinger, & Biswas, 2002), solvent extraction (Navarro, Simpson, & Alguacil, 1999), ion exchange (Arroyo et al., 2017), coprecipitation (Wang et al., 2003, 2018; Xiao et al., 2007; Xiao, Cao, Mao, Shen, & Ren, 2014), activated carbon adsorption (Navarro & Alguacil, 2002), electrodialysis (Cifuentes et al., 2015), redox process (Zhou, Peng, Zheng, Ma, & Cui, 2011; Peng, Zheng, Zhou, & Chen, 2012; Zheng, Peng, Ke, & Chen, 2013), among which the electrowinning method is simple in operation and effective in impurities removal, making it the main process for current electrolyte purification. Some copper ions can react with harmful impurities to form complex black copper sludge by controlling the operation conditions of electrowinning process. Based on the estimated data provide by Davenport et al. (2002), an annual output of 400,000 tons cathode copper could produce 432-2168 tons of black copper sludge by electrowinning method. Black copper sludge contains 30~50% copper, 15~30% arsenic and a small amount of rare elements such as selenium and tellurium. Thus, recovery of valuable metals can bring huge economic interests. Moreover, arsenic in these sludges could cause significant environmental pollution. Therefore, effective removal of arsenic from these sludges is urgent and significant.

Jan 1, 2019

By S. J. Cook

The system of mining statistics for Canada, as it exists today, represents the result of long years of progress, first by the Geological Survey, later and more comprehensively by the Mines Branch of the Department of Mines, and now by the Mining Branch of the Dominion Bureau of Statistics-all supplemented by the very comprehensive reports published by the several provincial departments of mines. It is the purpose of this paper briefly to state the development and present status of Canada's statistical service, more particularly in regard to information on mineral production, and to show that in its evolution continuous progress has been made in the elimination of factors tending to duplication and overlaping, with the result that the construction of an adequate statistical service has been carried out with the least possible expenditure of .public funds. For the purpose of this discussion, the subject of mineral statistics may conveniently be considered from two points of view. The technical difficulties in obtaining satisfactory and complete data from the variety of industries represented in the mining fields of Canada must be apparent to all. Methods of record-keeping are almost as numerous as mines and even the larger concerns which maintain elaborate records for their own information, often find it difficult to compile the statistical reports required of them, because the specific form of inquiry differs from the method in use in their offices.

Jan 1, 1924

By Charlie Jefferson

Main Goal: Resource Assessment 1. Incorporate existing data & results, old process. 2. NEW Quantitative Analysis (Chung and Chen) 3. Try mass balance of U and geochemical tracers 4. Use holistic process approach ?with key foci ?Targeted basin / belt assessments ?Is there as much in the Athabascaas they say? ?Athabasca reference for other basins (Thelon, etc) ?Compare sandstone & volcanic with USA, Kazakhstan etc: do their models apply here? ?Which IOCG systems are prospective for uranium? 5.Consider Groundwater, Environment; 6.Communicate

May 1, 2006

By Carlos Antônio de Morais, Renata Dias Abreu

The present work describes a study of the separation of terbium and dysprosium from heavy RE concentrate through a solvent extraction circuit in a counter-current system. As the efficiency of the REE extraction by acid extractants rises with the increase of the atomic number of the element, the aim of this work is to extract the elements with higher atomic number maintaining Tb and Dy in the aqueous phase. Thus, terbium was separated first with subsequent separation of dysprosium. The experiments were carried out by using IONQUEST®801 as the extractant and a REE-hydrochloric liquor as feed solution. The optimum operational circuit in terbium separation was comprised of 37 stages: extraction, scrubbing, stripping, and solvent washing. For the dysprosium separation 39 stages were required. Terbium separation over 92% with over 95% purity and a Dy separation over 97% with over 95% purity were obtained.

Jan 1, 2014

The hydrometallurgical treatment of copper ores and concentrates continues to be an active field of innovation. The direct extraction of copper from ores containing chalcopyrite is an important development to provide an alternative to flotation-smelting and refining. Jetti Resources (with the University of British Columbia) and the JX Nippon Group have developed process options for chalcopyrite heap leaching. Biological heap leaching developments for chalcopyrite are also continuing in parallel. These direct leaching technologies are also very attractive for arsenical ores. The atmospheric leaching of copper concentrates is an attractive option along with autoclave processing. The Galvanox™ Process is the focus of commercialization by InCoR Galvanox Holdings under exclusive license by the University of British Columbia. The Galvanox™ Process can be used to treat chalcopyrite or enargite containing concentrates to high copper extraction with simultaneous precipitation of arsenic as atmospheric scorodite. FLSmidth has continued development of the Rapid Oxidative Leach (ROL) and associated technologies for chalcopyrite leaching. The Glencore Albion Copper Process using ultra fine grinding of copper concentrates and atmospheric leaching has found application in central Africa. The pressure leaching of copper concentrates continues to be attractive for rapid, complete oxidation of sulfide minerals with high copper extraction and arsenic stabilization of iron-arsenate minerals and precipitates. The Ecometales PLCC project is designed to use high temperature total pressure oxidation for treatment of an arsenical copper concentrate with use of existing copper SX-EW facilities for copper cathode production. The excess acid from the autoclave process will be used to make up the acid demand for associated copper ore heap and dump leaching operations. INTRODUCTION The recovery of copper from ores is dominated by the flotation of copper concentrates followed by smelting—converting and electrorefining. This process has been enabled by the development of froth flotation and progressively made more efficient by advances in smelting and converting technologies.

Jan 1, 2019

By S. Xu, A. Ramesh, F El-dabbagh, Z. Fang, A. Sobhy, J. A. Kozinski

Waste remediation is a goal that will be driven forward by economic conditions. As the cost of waste disposal increases, new methods of waste reduction will become economically attractive, and will be implemented. It is difficult to imagine, however, a time when there will be no waste generation. For the foreseeable future, despite effective reduction practices, there will still be hundreds of millions of tons of waste that must be destroyed or controlled to protect the public health and the sanctity of the environment. To remain faithful to environmental covenants, the mineral and metallurgical industries will face these new challenges. This paper discusses novel waste remediation approaches and techniques focusing on hazardous wastes and thermal remediation. Aspects concerning technological and environmental importance are examined. Solutions for neutralization of environmentally hazardous compounds are proposed.

Jan 1, 2004

By Julie Q. Shang

The electrokinetic (EK) technology for dewatering of two tailings from the uranium mines in Northern Saskatchewan is studied in bench scale experiments. The study includes four phases: 1. Characterization of two uranium mine tailings; 2. Assessment of voltage loss on the coated Ti anode and water interface. 3. EK cell test series to measure electrokinetic permeability (ke) of two tailings; 4. EK dewatering test series to study electrokinetic enhanced gravity dewatering on two tailings samples. The results have demonstrated that both tailings responded positively to the EK process. For the tailings containing gypsum, the EK dewatering should be a short term process (within one hour) with anode conditioning (pH adjustment). The tailings containing clay minerals responded well to EK dewatering, in which pH adjustment is optional and will further enhance the EK flow. Both tailings as tested have low hydraulic conductivity and are particularly suitable for EK dewatering and consolidation.

Aug 1, 2010

By E. Busse, J. E. Burgener, J. G. Eacott, M. C. Robinson, P. E. Burgener

"This paper presents a preliminary assessment of the technical and economic feasibility of a caustic leach - electrowinning process for the recovery of zinc and lead from electric arc furnace baghouse dust at a mini-steelplant. Recent studies and literature are referenced briefly as they pertain to the formation and characterization of dust, toxicity considerations and alternative dust treatment and disposal options.Laboratory testwork results, published data, pilot plant experience and anticipated influences resulting from recycling residues are used for the purpose of developing a conceptual design for a caustic leach - electrowinning plant to treat 15,000 tonnes/year of dust at a one million tonnes /year capacity steelplant in Canada.Target economic studies, comprising preliminary estimates of capital and operating costs, revenues and rate of return are presented. Economic and commercial considerations concerning the relative merits of dust treatment at a centralized facility compared with an on-site plant are discussed.IntroductionThe treatment or disposal of mini-steelplant electric arc furnace (EAF) baghouse dust has been given increasing attention in recent years for two principal reasons. Firstly, the dust is now classed as a hazardous waste material under V.S. EPA regulations which prohibit its disposal in dumps other than controlled landfill sites. Secondly, the dust contains certain metal values, notably zinc and lead, which may be economically recoverable, depending on the costs associated with disposal resulting from enforcement of the EPA regulations. Other metallurgical dusts and waste materials, from both ferrous and non-ferrous operations, may require the same considerations as EAF baghouse dust.Several studies have been carried out to examine various aspects of dust treatment but few commercial plants are in operation. Technology employed uses pyrometallurgical techniques. Commercial-scale hydrometallurgical plants are not known to exist although small-scale plants are frequently more economically attractive than their pyrometallurgical counterparts which generally require economies of scale to be viable.The concentration of mini-steelplants in northeast V.S.A. and southeast Canada merits study to determine whether or not dust treatment for metals recovery is a commercially feasible alternative to disposal.This paper examines the technical and economic feasibility of a caustic leach - electrowinning process for the recovery of zinc and lead from EAF baghouse dust at an on-site ministeel plant processing carbon steel scrap and discusses economic and commercial considerations pertaining to dust treatment at a larger, centralized facility."

Jan 1, 1984

Strengthening a mine with the Power of their Employees: ?Imagine if the global economy collapses, your head office calls, and tells you to shut down for 3 months... now what do you do? ? HVC Business Improvement Initiative Why did we need help ? External Events ? How we responded ? How we worked with Westwind ? Alignment ? Priorities ? Coaching ? Focus Groups ? Innovation ? What worked / Opportunities ? Questions

Nov 1, 2011

By W. Zieman

"The low consumption of reagents can probably be attributed to a good clean type of ore. The cyanide level is kept at 0. 8 lb/ ton of solution and the lime at 1. 8 to 1.9 lb per ton of solution (pH 12. 2 to 12 .3). Experience in cutting down the lime level in half produced troubles in the presses, in the refinery and resulted in higher cyanide consumption. Finally the residue increased under these conditions, High lime always seems to prevent the trouble from occurring.A survey at one mine of the taxable work, performed in the mine shops for use in the mine, showed that under the new regulations, this had increased some 30 times what it was before the new rules came into effect on June 14, 1963.A water softener idea is incorporated at Lamaque with the crude addition of 100 lb of lime per shift to a spare agitator to precipitate the bicarbonates as carbonates from the water before it enters the mill. The lime titration of the softened water is about 0,2 to 0.3 lb per ton of solution (pH 11). This water is used mainly on the filters as washes."

Jan 1, 1964

By A. Fyson, M. P. Smith, Margarete Kalin

"Drums containing 0.07 m3 of pyritic waste rock from a zinc/copper mine, with and without Natural Phosphate Rock (NPR) additions (40 kg/t waste rock) were set up outdoors. The effluent chemistry has been monitored over a period of 709 days. In the presence of NPR, the cumulative acidity discharged from 7 out of 8 drums was 80 % less than that discharged from drums without NPR. Mixing NPR throughout the drums was more effective in reducing acidity than placement of the NPR in a layer in the drum. NPR treatment was more effective for 'fresh' waste rock than for material which had weathered for more than 4 years. It is concluded that application of NPR to pyritic waste rock could greatly reduce acidity generated.IntroductionWaste rock dumps are significant sources of acid, generated by the oxidation of sulphides. Oxygen and water supply are oxidation rate-controlling factors, and oxygen supply is the reaction-limiting component. If secondary minerals can be formed on the surface of the rocks, pyrite oxidation and therefore acid generation may be reduced or inhibited. Neutralizing agents such as limestone do not prevent the oxidation of pyrite but treat the resultant acid mine drainage (AMD) or acid rock drainage (ARD).Meek et al. (1991) determined in pilot scale experiments that apatite mixed with tailings was more cost effective than liming or use of PVC liners to reduce oxygen and water penetration into the tailings. Phosphate is not acting as a neutralising agent but it creates a chemical condition on pyritic surfaces which prevents reactions of the oxidising agents. Precipitation of principally iron phosphates physically isolates the pyrite surfaces from further oxidation (Ziemkiewicz 1990; Evangelou 1994). The chemistry of the phosphate effects has been described by Spotts and Dollhopf (1990). Secondary mineral formation was evident in the leach pile at Gibraltar when leaching was impaired (Scott, 1991) indicating a link between oxidation and the mineral-formation process. This paper reports on effluent characteristics when waste rock is generating acid in the presence of NPR."

Jan 1, 1995

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 D. H. Wilson

"This paper examines the increasing need for mechanical-electrical people within the industry and some of the reasons why such a shortfall exists. It is suggested that, in part, it is image related. The present industry-education relationship in addressing the situation is examined and some thoughts are expressed on how these may be built on, in order to help solve the problem of attracting people to this critical area.IntroductionAs a long-time proponent of plant engineering and maintenance as a management function, I would like to review the progress made by the industry/ educational approaches in satisfying the needs in that area. In doing so, I would like to make the following points:1) that there has been an accelerating shortfall of mechanical-electrical people relative to the needs of the industry;2) that the condition will probably get worse before it gets better; ,3) that the past industry I educational approaches to alleviate the problem have met with limited success; and finally4) I would like to review some of the things being done and consider how these efforts might be extended."

Jan 1, 1981