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By P. Bacher, L. Dubourg, M. Jahazi, G. Dezaise

Effect of friction stir welding parameters and natural ageing on weld properties are reported. Using a Taguchi design of experiment, attempt is made to systematically examine the influences of the welding speed, tool rotation speed, forge force, tilt angle and pitch ratio on the weld size and ultimate tensile strength of FSWed joints. One millimetre thick plates of AA7075-T6 were welded in lap joint configuration. Samples were characterized by optical microscopy, hardness and tensile measurements. Trends suggested by the results and directions for further investigation are discussed.

Jan 1, 2006

By N. K. Jaber

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

Jan 1, 2006

By V. A. Chanturiya, T. N. Matveeva, N. K. Gromova, T. A. Ivanova

"The research is aimed at solving the problem of increasing the extraction of gold from refractory ores, which are the main source of growth in gold production in the next decades. The purpose of the research is the development and scientific substantiation of the reagent modes for flotation extracting of gold from refractory ores using eco-friendly low-cost herbal modifiers (HM), providing increase in gold recovery and quality of gold concentrates. In the course of research laboratory techniques for the preparation of experimental samples of HM were developed, which included the sequence of operations of grinding Heraclium leaves and stems grinding, 2-stages extraction at a temperature of 50-60 °C, short-term ultrasonic treatment, filtration and subsequent unification of extracts. According to the developed method, the experimental samples of HM and conducted research were tested to analyze their sorption and flotation activity related to the extraction of gold from refractory gold ores.New data on adsorption and flotation properties of Heraclium stems and leaves extracts (HSE) in selective flotation of Au-sulfide minerals were obtained using UV-spectroscopy, scanning electronic and laser microscopy and atomic force microscopy. The dimensions and shapes of adsorbed hydrophilic films of herbal reagents were identified and mechanism of formation of stable insoluble compounds on the surface of minerals in flotation was explained.Research flotation tests carried out on samples of refractory gold ore of one of Russia deposits showed the possibility of effective use of herbal modifiers to improve qualitative and quantitative indicators of enrichment compared with the standard reagent regime. New reagent modes, using herbal modifiers in an amount of 5 to 10 ml of the extract (300 - 600 g / t, respectively) improves the quality of the concentrate: gold content attains 14.7 g / t, 1.34 times higher than in the baseline experiment and provides a gain of 3.13% extraction.The developed reagent regime with herbal modifiers is the author's original design, patented (patent of the Russian Federation) and have no analogues in the world of mineral processing. (Application number 2015116125 from 04.28.2015, ""The method of flotation separation of sulfide minerals using herbal modifier"", Russia). Actual application of new plant extracts as modifiers in flotation of sulfide minerals is the possibility of replacing of highly toxic chemical compounds by environmentally safe substances of plant origin. Implementation of the developed methods of extracting gold from refractory minerals with herbal modifiers will help to improve gold recovery at 3-5% and the quality concentrate of not less than 1.2 times, leading to higher productivity and a reduction of the negative man-made effects on the environment ."

Jan 1, 2016

By Roger Francis

There is increasing use of acid leach extraction methods at elevated temperatures and pressures by the mining industry. In many locations there are limited supplies of fresh water, and waters with higher chloride contents must be used, making conditions more corrosive. The fluids downstream of the main autoclave are hot, acidic, oxidizing and contain chlorides and present a challenge to the mining community to ensure reliable operation. Zeron 100 is a high strength superduplex stainless stee, that offers high corrosion resistance at a cost effective price. The paper presents a combination of laboratory data and service experience, particularly in the aggressive fluids found in downstream processing.

Jan 1, 2010

By K. Forsberg, A. Rasmuson, R. Rodriguez Varela, J. Martinez De La Cruz

"This study analyzes the separation of rare earth elements by means of a supported liquid membrane (SLM) with the final objective of recovering REE from an apatite concentrate (Alemrajabi, Forsberg, & Rasmuson, 2015; Mohammadi, Forsberg, Martinez de la Cruz, & Rasmuson, 2015). In this study, the feed phase consists of an aqueous phase containing REE, the membrane phase contains the organic solvent and carrier (D2EHPA and EHEHPA), and the stripping phase is a hydrochloric acid solution. An evaluation of mass fluxes, separation efficiency, and membrane performance is conducted. In order to analyze the suitability of liquid membranes in the extraction of REE, a deeper insight into the mechanisms causing instability is needed. In this study, surface tension is considered as the key factor of Marangoni instabilities and spontaneous emulsification.INTRODUCTIONThe demand of REE and their compounds has increased considerably due to their special physicochemical features that make them crucial elements for numerous high-tech applications, including wind turbines, hybrid cars, mobile phones, and defense technologies. They are also extensively utilized in traditional industries such as nuclear energy, petroleum, metallurgy, agriculture, and textiles (Xie, Zhang, Dreisinger, & Dyole, 2014; Zhang, Wu, Bian, & Zeng, 2014).Solvent extraction is widely used for the separation of REE (Xie et al., 2014; Zhao, Huo, Pan, Li, & Liu, 2014). Di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHEHPA) are two of the most effective extractants for the separation of rare earth elements among organophosphorus extractants (Gupta & Krishnamurthy, 2005). However, the difficulty in stripping loaded D2EHPA extractant, especially for heavy REE, has limited its utilization. Yttrium can be stripped at lower acidities in EHEHPA systems compared to D2EHPA systems (Gupta et al., 2005), but the extraction efficiency is lower. Conventional solvent extraction by mixer-settlers is restricted by its large solvent inventory and loading limits, and suffers from phase disengagement, emulsification, loss of solvent, and flooding problems (Swain, Jeong, Lee, & Lee, 2007). In this context, supported liquid membranes (SLMs) present a potential alternative due to their advantages, being low solvent inventory, process simplicity, low energy and operational costs, great enrichment ratio, and combination of extraction and stripping into one single step. A SLM is a system in which two aqueous phases are separated by an organic liquid membrane suspended in the pores of a porous support by capillary forces. One of the aqueous phases is the feed solution with the solute and the other is the stripping or receiving solution. The solute diffuses through the liquid membrane and then is extracted into the stripping solution (Kislik, 2010)."

Jan 1, 2016

By G. Marchand, R. H. Hay, E. C. Pearson

"AbstractA polishing .technique is described together with two anodic etching methods for aluminum and its alloys. Some of the optical and structural characteristics of the film formed by •these etching methods are discussed and it is shown to what degree these properties of the film are related to the crystallographic orientation of the metallic substrate. Applications to the study of recrystallization and twinning phenomena and to the study of plastic deformation, banding, and texture estimation are discussed. Micrographs are shown .to illustrate the manner in which the technique is particularly well suited to the study of such phenomena.IntroductionThe physical metallurgist is constantly faced with the problem of polishing and etching of metallic sections. Mechanical polishing is tedious, time consuming, and not applicable whenever a surface entirely free from plastic deformation is required. Etchants are generally required to reveal the grain structure in order to determine its size, shape, and regularity, or to bring up constituents. In the case of aluminum, the .most common etchant to reveal grains is a mixture of three acids: HC1, HN03, and HF. This etchant is fairly satisfactory on certain alloys and for certain metallurgical conditions but in general fails to give a good definition of the grain on castings, on highly alloyed products, and whenever the grain is smaller than 100 microns in diameter. Besides size and shape, a grain, or crystal, has an orientation and may be endowed with several types of imperfections."

Jan 1, 1952

By Muhammad Zaka Emad

Cemented rockfill (CRF) is a mixture of rock aggregate and binder slurry. It is a stiff backfill, it is fast curing, its operation is simple, placement rate is reasonably high and no drainage is required. The main demerit of CRF is failure of exposed faces causing ore dilution, which can be associated with the fill placement method. This paper discusses the effects of two placement methods being practiced by mines and numerical modelling is used as a tool to evaluate stability of the backfill column. In the first method, practiced in longitudinal retreat mining of a narrow vein deposit, the rockfill is hauled and dumped into the stope with a LHD scooptram. Once dumped, cement slurry is sprayed into the stope. In the second method, a raise situated centrally above the mined stope is used to convey already mixed CRF into the stope. Stopes are mined out transversely in primary and secondary blocks in a sublevel stoping system. Problems of poor mixing in combination with both placement methods are discussed. The two backfill placement methods are analyzed for blast induced vibration damage using the dynamic Flac3D modelling technique accounting for rock mass and fill damping characteristics, and a pressure wave is used to simulate the blast vibrations. Fill heterogeneity has also been considered for the two cases and results are compared.

Jun 1, 2012

By S. Uddin

Microsegregation manifests its effect on microstructural evolution of cast or welded alloys which in turn influences their important mechanical and electro-chemical properties. In the above context, mathematical models of microsegregation have proven to play an important role in estimating the nature and predicting the effects of this phenomenon in wide varieties of solidification processes. Microsegregation models are useful in designing new commercial alloys, in estimating the homogenization time for the post-process heat treatments and in many other practical applications. In this study, two semi-analytical models of microsegregation were developed to predict the concentration field of solute in the liquid and solid regions for dendritic solidification of binary metallic alloys. Both models assume that the growing dendrites are cylindrical in shape. This assumption is more realistic compared to the common assumptions of plate like dendrites that most of the earlier researchers employed in their microsegregation modeling study. The solute redistribution profile, in the developing solid layer, necessary to determine the back diffusion parameter was derived from Fick's second law for the model without coarsening. The application of this parameter in a wide range of conditions and the use of its basic form in the model with coarsening has been verified. The concept of coordinate transformation and enhancement of back-diffusion Fourier number were used in deriving the model which took into account the coarsening of dendrites. The models are then extended to deal with rapid solidification and peritectic transformations and the results were compared with relevant experimental data for Aluminum and other alloys. A good agreement between model predictions and experimental results was found.

Jan 1, 2007

By M. Pearson, L. Zunti

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

Jan 1, 2004

By Andrew Matyas

"During the summer of 1968, the author was employed in the Research Department of Dominion Foundries and Steel, Limited, Hamilton, Ontario. Over the years, Dofasco has been conducting a program for developing more efficient control of its basic oxygen steelmaking process. The author was thus able to obtain a variety of viewpoints from both research engineers and furnace operators. He also had access to extensive literature dealing with BOF control schemes underway at other major steel producers. This paper describes the present state of developments in BOF steelmaking control.The necessity for efficient BOF control is pointed out. To appreciate the variables to be controlled, a brief outline of process fundamentals is included. Technical aspects of present methods of practical control are examined in detail; the relative merits of dynamic over static control models are emphasized. Finally, it is shown how an effective dymic-optimizing control scheme serves as the basis for closed-loop computer control of the process."

Jan 1, 1970

By W. A. Bain

"AbstractProduction from the Excelsior Reservoir has amounted to approximately one million barrels. This production has caused a 'Pressure •drop of 10 p.s.i. from the original pressure of 1,245 p.s.i.g. Volumetric balance calculations indicate that the pool as being produced by a water drive whose strength is •probably unsurpassed in Western Canada. It has also been shown by 'unsteady state' calculations that the reservoir will still be above the saturation pressure of 915 p.s.i.g. at the time of depletion. The average permeability of the producing formation is approximately 1,000 millidarcys and, consequently, well draw-downs are very low. The field is essentially a bottom-water drive and calculations have shown that gravity drainage will greatly assist the recovery of oil. Water flooding data on several cores •have placed the flushing efficiency at •approximately 50 per cent, which indicates a recoverable oil-in-place of 17.7 million stock tank barrels. Calculations and field data indicate that the MER for the early life of this field is probably as high as 8,000 to 10,000 stock tank barrels per day.IntroductionTHE EXCELSIOR NISKU oil reservoir is located about twenty miles northeast of Edmonton. The field was discovered in November, 1949, by Imperial Excelsior N.o.1 well, in Lsd. 13, Sec. 3, Twp. 56, R. 22, W. 4, at a depth of 3,850 feet.Since discovery, development has continued on a 40~acre spacing pattern. At the end of 1951, drilling over approximately 80 per cent of the estimated productive area of 1,680 acres had established 32 we1ls capable •of production. The field •has been fairly well delineated by dry holes on all but the eastern flank ."

Jan 1, 1952

By A. Moyano

The development of the traditional converting process performed in a PeirceSmith or Hoboken converter is limited by the investment magnitude associated to the fulfillment of the environmental regulations. Thus, the continuous converting process rather than a conceptual process alternative is becoming a necessity for a smelter facing limited converting capacity and/or lacking of fulfillment of the environmental regulation with its maximum converting capacity. The objective of this paper is to present the progress of the Codelco continuous converting process evaluated at pilot-scale level when converting solid mattes or white metal into blister copper. These tests allowed for gathering of relevant data to be considered for a new stage of evaluating the Codelco continuous converting at industrial-scale test. The pilot-scale tests were done in a Teniente Converter pilot scale unit at the Codelco Norte Smelter. The results of processing solid copper mattes (65-75% Cu) and producing low sulfur content blister copper with production of a constant S02 gas concentration, and the production of liquid slag with low copper solubility was achieved and is discussed in the present paper.

Jan 1, 2007

By W. B. Boggs

A paper describing the Noranda smelter was presented at the 1930 annual meeting of the Institute (1). A lacer article appeared in the Trans-actions of the A.I.M.&M.E. in 1933. Since that time there have been many changes and improvements in plant operation and it is the abject of this paper to give an account of developments up to the beginning of 1939. The Noranda smelter was built originally for a capacity of 30,000 tons a month. At present, the average tonnage being treated is 110,000 tons a month, the tonnage of custom ores alone amounting to almost the total rated capacity of the original plant. This increase has been accomplished by increasing the capacity of the reverberatory furnaces from 700 tons of solid charge per furnace day in 1928 to 1,500 tons per day at the present time. In 1935, it appeared chat the limit of furnace capacity had been reached at about 1,300 tons of charge per day because of the short life of the sprung silica arches. However, the adoption of the suspended magnesite roof, which had been developed at the Flin Flou smelter of the Hudson Bay Mining and Smelting Company, overcame this difficulty and it is believed that the limit of the capacity of the present reverberarory furnaces has not been reached. A brief account of the changes to equipment in the various departments will be given, followed by a description of the more important features of present smelter practice.

Jan 1, 1939

By C. C. Li

The D bolt is a new type of energy-absorbing rock support element recently developed in Nor-way. The D bolt is not only able to accommodate large rock deformations, but can also provide a load-bearing capacity as high as that of rebar bolts. Furthermore, the anchoring quality of the D bolt is similar to rebar bolts because of its multi-point anchoring design.

May 1, 2009

By A. V. Lyamin, J. P. Wang, A. J. Li, Z. Qian

"For general stability analysis of rock slopes, rock mass strength and rock mass disturbance are definitely should be considered. In addition, the impact of earthquakes must be taken into account. In fact, the rock mass strength is very difficult to be assessed which causes the difficulty of analysing rock slope stability. Therefore, an empirical failure criterion, the Hoek-Brown failure criterion, has been proposed. It is one of the most widely accepted approaches to estimate rock mass strength. The rock mass disturbance is important and was found having significant influence on evaluating rock slope stability, especially for rock slope with poor quality rock mass. In the Hoek-Brown failure criterion, the disturbance factor can represent the level of the rock mass disturbance which would provide a reasonable basis for estimating rock mass strength.This research will not only discuss the slope factor of safety, but also consider the influence of the seismic force on rock slope stability assessment using pseudo-static method. In practice, only horizontal seismic coefficient is used. Various magnitudes of the disturbance factor and recommended blasting damage zone thickness are also taken into account. The blasting damage zone thickness considered ranges from 0.5 to 2.5 times of slope height. The research results have potential to be extended and then sets of comprehensive stability charts can be provided for the rock slope stability evaluations. They will be convenient tools for practising engineers. In this study, finite element upper bound and lower bound limit analysis methods are employed. Their applicability has been investigated in some previous studies. The differences between upper bound and lower bound solutions are less than ±10% which would provide reasonable and acceptable range for rock slope stability safety factor estimation."

Jan 1, 2015

By F. Nava-Alonso, A. Uribe-Salas, C. Rodriguez-Rodriguez

Ozone has been proposed to pretreat refractory ores before the cyanidation process for precious metals extraction. As pyrargyrite is one of the silver species most common in Mexican refractory ores, the ozonization of this silver sulfide was studied. The effect of pH and ozone concentration on silver dissolution was evaluated by means of a factorial experimental design. Two levels of sulfuric acid concentration and ozone in gas concentration were evaluated: 0.18 and 0.72 mol/L of acid and 0.054 and 0.077 gO3/L, respectively. The highest silver dissolution was obtained when using the higher acid and ozone concentration.

Jan 1, 2011

By A. J. Paul Laprairie

"ADVANCE planning of mining methods, from the first development openings to stope layout and pillar recovery, has long been accepted as a normal method of operating a mine. Recently, mine managers have become increasingly aware that advance planning of cost and accounting controls can also be considered a normal method of operation. The use of such controls is wide-spread in manufacturing industries. In mining, the gold mines of South Africa have pioneered, with marked success, in this field and have been closely associated with most of the research and field work in accounting control. Canadian mine managers are also beginning to realize the advantages of using planned costs. The control procedures which subsequently have been introduced at various mines have come to be known by such names as ""Responsibility Costing"" or Budgetary Control"".Budgetary control, the term used in this paper, is based on the concept of decentralized authority with centralized control. ;The control is achieved by measuring results against yardsticks which are in the form of budgets or standards. Bud-gets are made for the future activities of each possible operation as planned by the department head, and attention is directed to variations from this plan. Furthermore, the control process charges to each operation only those costs which are incurred directly for that operation, and which can be controlled by the person in charge. Thus, budgetary control relates results to the officials responsible for those results. Expenditures are analyzed according to the organizational structure of the mine and the people who run it, and not according to production processes."

Jan 1, 1960

By P. V. Golde, R. A. Poole, G. R. Baiden

"INCO is committed to proceed into the next century using automation and robotics to achieve safety and productivity goals necessary to enhance its competitive position. Stobie Mine, decades old, is the first of its mines to change from labour-intensive to automationassisted techniques. This paper is a synopsis of the progress made during the transition period including overviews of some of the projects as well as some of the difficulties in the assimilation of the technology. BackgroundThe ObjectiveThis paper is an update on remote control and LHD automation installation at Stobie mine. The communications system installed at the mine and the ability to remotely control underground equipment from surface is reviewed (Poole et al., 1996, 1997). It discusses some of the experiences and processes required to further the concept to consolidate the operation of multiple machines under a single operator. It considers the communications systems requirements and their focuses, particularly on the development of systems for the tele-operation of LHDs and drilling machines from surface."

Jan 1, 1998

By Wm. D. Jr. Sheldon

THIS paper presents practical data to aid in the selection of a mine ventilating fan, and outlines considerations to be made to ensure satisfactory operation and optimum efficiency of the fan. Much has been published on the general subject of mine ventilation, but the writer has found few specific data on factors and considerations which govern the selection of a fan-data which should be available to the operator if his fan is to give satisfactory service within the range of the high-efficiency portion of its performance curve and deliver the specified air capacity when operating against the anticipated range of resistance of the mine. The total quantity of fresh air furnished by the ventilation system must be adequate to provide, and to ensure at all times, safe and healthful working conditions in the mine. It is assumed that the mine operator is able to determine the air quantities required for the various parts of the mine.

Jan 1, 1941

By John C. Leighton, C. O. Brawner, Doug Stewart

"Despite the availability of established, sophisticated methods for planning and designing stable slopes in rock, comparatively little attention is usually paid to the problems of carrying out the excavation. Blasting should be carefully planned to obtain optimum fragmentation as well as steep, stable working and final pit walls. The principal difficulty facing a blast designer is the lack of prior information about the many critical blasting characteristics of the rock mass. The common practise of trial-and-error lasting will eventually lead to a suitable program, but must be repeated time after time in variable geology. This frequently results in many blast-damaged slopes. Recent research indicates that monitoring drill performance will yield a Rock Quality Index which correlates to a Powder Factor value. The drilling can provide a continual supply of data, reflecting changes in the rock mass which enables the selection of an economical powder factor.IntroductionWhen planning to excavate a large-scale rock slope, engineer s will generally spend considerable effort to produce a safe, feasible and economical design. Much time will usually be spent on the field map ping, 'structural geologic studies, surface and subsurface hydrology, determination of strengths and effective friction angles of discontinuities, and finally checking stability with the aid of mathematical and analytical models. If the rock cut is to be along a transportation corridor, the prime justification for this time and effort is to produce a clean, stable slope which will be safe for those travelling or working beneath it. For the walls of an open-pit mine, there is the additional economic incentive to maintain the steepest stable slope angle for the minimum stripping ratio (Stewart and Kennedy)."

Jan 1, 1982