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By K. Prajapati, P. Hes

Transmission of vibration to the operator from percussive vibrating tools is increasingly of concern in industrial and mining applications. Prolonged exposure to high levels of vibration transmitted via the hand causes disorders known as hand-arm vibration syndrome (HAVS). The vascular component of HAVS is called vibration white finger (VWF) and has a debilitating effect on the hand. Vibration at frequencies below 1250 Hz, a tight hand-grip force and cold environments are reported to increase the likelihood of developing VWF. A vibration damping handle design with patents pending that addresses some of the causes of VWF has been developed and retrofits onto jackleg pneumatic rock drills. The handle is decoupled from the drill while maintaining jackleg twist-grip controls on the hand-grip using a combination of sealed self adjusting hydraulic pistons and compliant materials in series, and a new air control valve. The ergonomics of the hand-grip was also modified by the addition of a polyurethane sleeve with a diameter of 50 mm. The new hand-grip reduces direct cold metal contact and minimizes grip force. Measurement of vibration as the quantity acceleration was made in accordance with international standard ISO 5349. Overall vibration damping in all axes of 50% to 63% was attained at frequencies below 1250 Hz. The dimensions of the damping handle are comparable and its weight is only 100 g heavier than a standard handle.

Jan 1, 2001

"In the present study, the reduction behavior of composite pellets comprising of iron oxide, synthetic graphite and slags were investigated in a laboratory-scale horizontal tube furnace. Two different types of slags indicating silicate base and aluminate base slags were chosen to examine the effect of slag chemistry on the reduction behavior of pellets. Slag composition of binding materials has influences on the reactions occurring in composite pellets during direct reduction. In-situ high temperature visualization approach was used to observe the slag / iron / carbon interactions at 1773K (1500°C). The off-gases were measured by means of infrared analyzer to determine the reaction rates of the pellets. Different physical appearances during the in situ reaction inferred a strong correlation between the slag composition and internal reactions. In addition, compression tests were conducted to examine physical strength of the pellets. This investigation was carried out to establish feasibility of physical property control of pellets by selecting optimum slag compositions of binding materials INTRODUCTIONCurrently, most of the iron ore mines have facilities that make an ore more usable for the blast furnace operation by improving its physical properties (e.g. pelletizing and sintering). However, during the process, a large amount of fuel is supplied to indurate materials which consequently deteriorate energy efficiency and produce more CO2 emission. Along with increased interests, direct reduced iron (DRI) making process; simply without coke oven or sintering process, has opened the era of clean and environmental friendly iron making process. While some of the established DRI technologies such as Midrex and HYL were restricted to certain locations where natural gas is abundant, coal based technologies using Rotary Hearth Furnace (RHF) such as FASMET and ITmk3 have been developed with regardless of expensive fuel deposit. In addition to the direct use of pulverized non coking coal and fine iron ore, RHF process also has advantages of utilizing waste materials such as EAF dust, biomass and recycled plastics. Nevertheless, there are still many challenges in the coal utilizing technologies as the unprocessed coal and the waste materials contain huge volatiles and ashes. Although recent investigations on volatiles in a RHF process (Sohn and Fruehan, 2005, 2006) have indicated the benefits of coal in terms of iron oxide reduction and have shown feasibility of multi-layer process, carbon composite pellets still have disadvantages because of its weak mechanical bonding strength. As the mixed system with carbon and oxides generates intermediate gases (e.g. CO and CO2) between solid particles, it is difficult to keep its physical state without the help of binding materials. In this reason, industries have been tried to use various binding materials such as bentonite, kaolinite and Portland cement. However, they are still struggling to find out new materials that provide not only sufficient mechanical strength but also metallurgical properties, such as porosity, reducibility and swelling throughout the reduction reaction. Recently, Canadian researchers (Aota et al, 2006) observed enhanced mechanical strength of pellets by using high alumina cement as a binder and concluded that the method could be used to recycle EAF dust as well, but in depth mechanism of reinforced strength has not been concerned. Most of the ashes coming from binders formulate certain type of slag during the reduction process due to its incombustibility. Thus, observation and regulation of slag property is an essential for the control of carbon composite pellet. Yet, only a little thermodynamic consideration from the perspective of slag chemistry has been adapted in the iron and steel making industries as ash has been easily ignored for its tiny proportion. In this study, effect of CaO-SiO2- Al2O3 slag system on the reduction of iron oxide was investigated in terms of"

Jan 1, 2012

By J. R. Giegerich

"IntroductionMINING operators in common with other operators are confronted today with two serious problems, shortage of experienced workmen and rising costs. The following review of practices at the Sullivan mine of The Consolidated Mining and Smelting Company of Canada, Limited, outlines certain measures that have been responsible, during recent years, for minimizing the effect of these two problems. The paper is divided into three main sections:( 1) Training programmes and job studies( 2) Improved mechanization and equipment( 3) Large-scale methods of operationTraining Programmes and Job StudiesJob TrainingJob training courses were introduced at Cominco immediately after the last war and proved to be a great benefit to the operations. There were three courses given, Job Instruction Training, Job Safety Training, and .Job Relations Training. These were spread over a period of two years and were taken by all operating supervisors and some key operators.The courses were introduced by a trained instructor from the British Columbia Department of Labour. This man trained twelve of our employees as instructors by giving them an intensive one-week course. Similarity between the three courses was such that the instructors trained in the first one were very readily trained for instruction in the two succeeding courses."

Jan 1, 1952

By H. H. Bleakney

THIS paper presents evidence that in 3 1/2% nickel steel, the published temperature for the Ac1 transformation, l,275°F., represents the completion of that transformation, and that its inception occurs approximately 275°F. lower, at about l,000°F. The formation of austenite within this range, especially at the higher temperatures, and its subsequent decomposition to martensite, results in considerable impairment of the properties of the steel. That the solid solution found to occur below l,275°F. is austenite has been questioned, but the evidence herewith presented, while not decisive, appears to be reasonably convincing. INTRODUCTION The February, 1939, issue of Metals Technology contains a very interesting paper by I. N. Zavarine, Associate Professor of Metallurgical Engineering at the Massachusetts Institute of Technology. In that paper, Professor Zavarine presented photomicrographs illustrative of the microstructures produced by heating nickel steels to a temperature slightly below the carbon change point, and holding them at that temperature for various lengths of time. His illustrations show that the structures found after such treatment do not consist merely of ferrite and carbides, but are characterized by the presence of a third phase, which he describes as a' 'sub-critical solid solution'. The occurrence of this third phase in increasing amounts is accompanied by an increase in strength and a loss of ductility and impairment of elastic ratio of the steel. Some years ago, one of the authors encountered the above-mentioned phenomenon in treating large forgings of 3.5% nickel steel. After normalizing and then drawing at l,250°F., very poor mechanical properties were obtained. Investigation of the steel disclosed no inferiority in quality. Eventually, after considerable waste of time and money, a draw temperature of l,150°F. was tried. This treatment resulted in a very great increase in elastic ratio, over 5 per cent increase in percentage elongation, and proportionate improvement in reduction of area.

Jan 1, 1941

By Shin-Kun Ryi

The world nowadays faces many challenges associated with excessive utilization of fossil, fuels, such as poor air quality and greenhouse gas emissions. Hydrogen appears to be an attractive alternative to the conventional, fossil, fuels with better energy efficiency and less environmental, impact. Pd and Pd-based alloy are the most often used membranes for hydrogen separation due to their superiority over other membranes. However, the stability of the commonly-used thin Pd-based composite membranes at high temperatures still, remains a big challenge. In this presentation, we will, report our progress on thin Pd-Ru alloy composite membrane by electroless plating high temperature applications.

Jan 1, 2010

By Kurt Tischler

This paper presents the field experience of Siemens with regard to Gearless Drives in the mining industry ? We consider the elapsed production hours of Siemens Gearless Drives to be extensive enough to provide a reliable estimation of availability calculated on the basis of data representing repair time, downtime, and operating time. The users of Siemens Gearless Drives confirm an availability of more than 98% after exclusion of some major issues. The paper addresses all of these major issues of Siemens Gearless Drives, describes successfully applied corrective measures, explains the influences on the design of the drives, and lists the downtimes associated with each of these issues.

Jan 1, 2012

By P. C. Parsons, G. C. Milligan

"IN FIELD WORK in the Cape Breton Highlands, which are heavily covered with vegetation, it is necessary to run traverses along the valleys of small brooks. We encountered difficulty in closing such traverses, and the following technique was developed to solve this problem. It has been tested in the field for four seasons by several people, and found to be simple, efficient and more accurate than any other compass-and-pace system of which we are aware. So far as we can find, the technique has not been described previously. It may be of use to others.The Cape Breton Highlands of Nova Scotia consist of hills of old intrusive and metamorphosed sedimentary rocks protruding up to 1,000 feet above the general level of the younger sediments which underlie the valleys. The flat hill-tops are the remnants of a plateau; drainage off the edge of this plateau has produced many small steep brooks. They occupy valleys which are up to 800 feet deep, and V-shaped in cross section, with steep sides covered by mixed conifers and hardwoods. The stream at the bottom is rarely more than a few feet wide, with a negligible meander belt, but with many bends, rapids and falls. Visibility along the stream, in consequence, is rarely more than a few hundred feet, and in many places much less.It was found impractical to map the streams by the method of meander lines, as described in many standard surveying texts and hand-books. The limited visibility, and the numerous bends of the brooks, necessitated many corners. Every corner introduces errors. To 'close' a survey with 40 or 50 such corners proved either very time-consuming or impossible. In most cases, however, the general direction of a valley may be obtained from an aerial photograph, or by direct observation, and this became the basis of the method adopted."

Jan 1, 1971

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

DOME MINES, Limited, is a gold producer situated in the Porcupine area of Ontario, 500 miles north of Toronto. During the year 1960, '71 4,600 tons of ore were milled, yielding gold bullion valued at $6,025,370. Prior to conversion to natural gas, an average of 3,200 tons of coal was consumed annually, one third of which was obtained from Canadian sources with the remainder coming from the United States. Due to the distances involved, the freight charges increased the pithead cost by as much as ISO per cent. Steam is generated at a central boiler plant and used for timber treatment, plant heating and process steam. Until August, 1960, steam was supplied during the winter months by two water tube coal-fired boilers, each rated at 200 boiler horsepower at 100 per cent output. Steam requirement was as high as 150 per cent of boiler rating in the colder periods. The summer load was

Jan 1, 1962

By R. W. Allgood

"THE world-wide shortage of elemental sulphur, which became sharply apparent in 1950, has focused attention on the commercial exploitation of sulphur-bearing materials such as pyritic ores, sour natural gas, and smelter gases. Although there •are no known commercial deposits of elemental sulphur in Canada, there are vast quantities of these sulphur-bearing materials. The International Nickel Company of Canada and Canadian Industries Limited have for many years collaborated in an effort to develop economic processes for the recovery of sulphur from the smelter gas arising from Inco's metallurgical operation at Copper Cliff, Ontario. While sulphuric acid has been •produced at Copper Cliff for over twenty years, recent developments will result in a 60 per cent increase in acid production early in 1952 and, later in the year, in commencement of the operation of the largest single unit ever erected for the manufacture of liquid sulphur dioxide.The purpose of this paper is to discuss •briefly the general factors associated with the recovery of sulphur from the Copper Cliff smelter gases and to describe the sulphuric acid operations and the liquid sulphur dioxide development.Processes for the manufacture of elemental sulphur, liquid sulphur dioxide, and sulphuric acid from sulphur-dioxide-bearing smelter gases are well known and in some cases •highly developed."

Jan 1, 1952

By T. V. Lord

Minerals containing uranium have been successfully pre-concentrated by flotation at Queen's University, Kingston. In particular, uraninite, uranothorite, euxenite, and fergusonite, have responded to flotation to yield grades of 0.2 to 6.0 .per cent U .o. with recoveries of 85 to 98 per cent, from heads analysing approximately 0.10 per cent U3Os. Of the ten or so radioactive samples examined to date, two distinct groups were recognizable, firstly, those samples in which uranium was the sole constituent of economic interest, and, secondly, those in which Columbium (with minor amount of tantalum) was present in addition to uranium. For the purpose of this paper, the results of investigation on two samples of each of the above groups have been selected as typical.

Jan 1, 1945

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 H. Vendette, N. R. Dando, A. Moras

The thorough analysis of results obtained from different testing campaigns performed on an alumina dry-scrubber pilot installation treating aluminum potline offgases, suggests a clear relationship between the emissions of gaseous fluoride and the fluoride saturation level of the alumina. The integration of this relationship into the development of a new generation of alumina dry scrubber represents an intriguing challenge regarding the design of more efficient air pollution control equipment. An innovative scheme challenging conventional industry practices was proposed. From theoretical simulations, the reduction in fluoride emissions can potentially be reduced by as much as 50% in the summer season. To validate this innovative approach, Solios in partnership with Alcoa Primary Metals, modified one of the Aluminerie de Deschambault's systems by adding new temporary equipment on the operating units and subjecting it to several test campaigns. This article presents the first results obtained in testing this new and innovative approach on alumina dry scrubbers used to capture fluoride emissions coming from aluminum electrolysis potlines.

Jan 1, 2006

By Chris Harris, Kamal Adham

The use of HCl acid is gaining momentum among hydrometallurgical processes. However, the issue of environmentally efficient and economically viable ways to regenerate HCl acid (from various metal chloride intermediate products) remains a technology and operational challenge. The authors provide a state-of-technology review based on Hatch’s years of testing, design and commissioning experience with high-temperature units (fluid bed and spray roasters), plus the recent efforts in the area of low-temperature HCl regeneration.

Jan 1, 2014

By D. Verhulst

The Altair process digests ilmenite concentrate in high-chloride HC1 solution, with complete dissolution of titanium and iron. The Fe(III) ions are reduced to the ferrous form, and the solution is cooled to produce crystalline ferrous chloride. Titanium is transferred by solvent extraction into a purified, concentrated Ti stream, which is spray-hydrolyzed to produce TiO2 hydrate. The hydrate is further calcined with additives to generate a high-quality pigment. All the chloride streams are recycled. In the original flowsheet, the iron chloride is pyrohydrolyzed by spray roasting to regenerate 18% HCl, which is subsequently converted to HC1 gas and water by pressure-swing distillation. A modified flowsheet includes an alternative to iron chloride spray roasting, producing more concentrated HCl and decreasing the amount of solution to be distilled. Improvements in digestion, solvent extraction and final pigment production are also introduced. A 100 t/y pilot plant is being built and will test the new concepts and confirm the overall water, acid and impurity balances of the process.

Jan 1, 2006

By W. F. MacIsaac

"The large low-grade Copper Mountain deposit is located in the northern portion of the Gaspé Cooper Mines property. It is approximately 1 mile north of the Needle Mountain deposit. The orebody outlined to date lies in the top 1,000 feet of the Grande Greve formation. Chalcopyrite occurs in association with pyrite and quartz in small veinlets and numerous fractures. The deposit is immediately adjacent and parallel to a quartz-feldspar dyke and may be associated with a nearby porphyry stock. Stratigraphy, alteration and structure appear to have played an important role in ore deposition."

Jan 1, 1969

By P. C. Patnaik

Performance of industrial gas turbine engines in terms of power output, reduced cooling and efficiency have been continuously increasing in parallel with aero gas turbines due to the advances made in the development of new materials, protective thermal barrier coatings (TBCs) and the advanced diagnostics to monitor service induced problems such as hot corrosion, thermal and thermo-mechanical fatigue and other operational issues, Environmental attack (hot corrosion or high temperature oxidation) is a common degradation mode in the hot section of the gas turbine, Hot corrosion occurs when Na or K bearing compounds in the environment or in the fuel combine with other contaminants such as S and Pb or V to form corrosive sulphates or vanadates thus attacking the protective oxide on the turbine airfoil, These problems pose far more threat to new turbine engine materials such as directional solidified, single crystals and ceramic matrix composites (CMCs). The CMCs due to their increased temperature capability, when used in the combustion chamber, are likely to reduce the peak temperatures attained during combustion and therefore provide the benefits of reduced emissions of oxides of C and N, These issues will be reviewed critically and their impact will be assessed on gas turbine lives. With respect to alternate fuels, past experience has shown that utilization of residual oils and coal derived fuels in gas turbines have resulted in complex deposition and corrosion processes, In recent years biomass derived alternate fuels have been used either through a gasification cycle or through direct firing of the biomass derived liquid fuel with a view to reduce Green House Gases (GHGs) and improve the climatic conditions. In both cases, the resulting high temperature corrosion processes (in the presence of alkaloids in the fuel) are also very complex, leading to premature removal of hot section components, Technology solutions mitigating these fundamental problems will be reviewed and solutions presented.

Jan 1, 2005

By Barbara Kirby

Mining Industry HR Challenges Mining industry needs to hire approx. 100,000 workers by 2020 Attraction and retention of talent in all occupations Mobility of skilled workers between mine sites 70 percent of employers expect labour shortages over the next 5 years. Largest shortages: -physical sciences and engineering occupations -trades and ?undesignated? occupations ?Undesignated? Occupations ?Undesignated? Occupations -eg. mill operators, production / development miners and heavy equipment operators More than 20,000 workers will be needed by 2020 in the undesignated occupations and another 11,500 tradespersons Turnover rate for trades and undesignated occupations at mines is high: 8.3% compared to 5.6 % for all other occupations There is no system to recognize the skills of high-demand undesignated occupations

May 1, 2010

By M. Hajian Heidary

In this investigation, effect of pressure depth on the globulizations of AZ91 magnesium alloy was studied. Cylindrical samples of AZ91 alloy with 1 cm and 2cm in height and 2.5cm in diameter (H/D = 0.4 and 0.8) were prepared, then the samples were hot pressed at 10 and 30% strain at a constant temperature of 200°C; subsequently reheated at 555°C in different times. Results obtained from optical microscopy (OM) showed that the thickness of the samples and consequently, depth of strain affected regions have remarkable effect on the degree of globulization. In addition, it was found that at a constant strain and holding time, structure of thinner samples is more globular than thicker ones.

Jan 1, 2007

By M. Somppi, D. Weirmeir, Z. Yamak

"Milling operations commonly employ activated carbon to capture complexed gold from lixiviants in leaching processes. As the carbon moves through pipes, pumps, vessels, kilns and other processes in the gold leaching circuit, this consumable may experience losses by various mechanisms like attrition, breakage, and rupturing. Whenever possible, capturing the fine gold-bearing carbon portion of this stream could provide value to milling operations at low capital cost and manageable financial risk. Identifying, testing, and validating the successful payback of a low-tech flocculant system is described. However, the work more closely explores a Monte Carlo risk-based methodology for understanding the potential payback of this project at various confidence levels – an approach that many improvement projects can follow where some level of uncertainty exists.INTRODUCTION Gold milling operations commonly employ activated carbon to adsorb gold from solutions. Normal handling causes the carbon particles from this material to abrade, break, rupture to a size that becomes too small for further use in the process. Operations often concentrate on capturing the fine particles because gold is associated with the carbon and this metal content can be a valuable revenue stream for toll processing. However, the small particle sizes become difficult to separate from the process and can ultimately leave the facility in the waste stream. Hence, operations often place a great deal of care in capturing as much fine carbon as possible by a variety of methods including using screens, settling tanks, and chemical methods. Retrofitting a circuit to capture more carbon fines is common but can expose the operation to financial risk. Approaching this potential improvement by leveraging a Monte Carlo methodology can be effective in understanding the risk and the associated payback of a project at various confidence levels. This method provides a strong framework for capital go-no-go decisions and the structure to validate the potential project success before implementation."

Jan 1, 2019