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By K. J. K. Weglo, M. U. Savich

"At the Falconbridge Limited, Canadian Nickel Division, Sudbury Operations, we investigated the ""NO NOISE"" ear muffs model NN3-F which is a Swedish product with foam-filled sealing rings (the Hellberg Standard Volume Hearing Protector). It is used extensively at Falconbridge mines in Sudbury.The research which was carried out in the four Falconbridge mines was conducted under three different headings: manufacturer's attenuation data (psychophysical method), clamping force and head size (bizygomatic diameter), and attenuation tests (physical methods) under working conditions.Manufacturers of hearing protectors claim their products offer noise reductions of 23 decibels (NRR) or more, but they fail to point out that this reduction is obtainable only under ideal conditions. The reality of attenuation under working conditions, as several studies have found, is quite different.Methods for using short measurements to determine the noise exposure index, and for controlling muff-wearing habits, were developed at the Elliot Lake Laboratory. Measurements taken at Falconbridge on ""NO NOISE"" ear muffs revealed that they have a practical attenuation of some IO to 13 decibels. It is important to note here that measurements also revealed that clamping force (thus attenuation) was in an inverse relationship with ear muff comfort. Measuring attenuation using noise dosimeters was a difficult job. Not a single surveyor would accept these measurements (physical method) for absolute accuracy. Apart from that, it was impossible to measure, in one shift, more than two work stations. Because of this, we sought a solution: measuring head size and clamping force in relation to actual attenuations.A detailed analysis of the relationship between attenuation and head size/clamping force was done at four mines. Standard deviation ellipses (standard error ellipses) for head size versus clamping force are in close agreement with measurements that were carried out. In order to measure clamping force an apparatus was constructed and a method for measuring suspension system durability is described in Appendices Band C of this report. At the same time we sought to reduce deterioration of ear muffs in mines as well as to put in place a system whereby attenuation can be controlled and improved. The clamping force apparatus can be operated automatically. The proposed control system is quick, simple and efficient . This system is equally applicable in small and large mining operations, and it can be totally automated and the data computerized for audit of the results. This control system is a new step in controlling ear muff attenuation in working environments.From these measurements of NN3-F ""NO NOISE"" muffs it can be concluded that ear muffs are not the total solution to protect the worker from noise.As the results were evaluated folio wing measurement, Falconbridge switched from the NN3-F ""NO NOISE"" muffs to approximately 90% Mark V ""NO NOISE"" muffs and 10% Mark V MSA muffs. These new muffs showed much better head size versus clamping force relationship and can be expected to produce 14 dBA or better attenuation of noise. RESUMEUne étude des casques antibruit ""NO NOISE"" modèle NN3-F, de fabrication suédoise, avec anneaux d'étanchéité en mousse (dispositif de protection contre le bruit ""Hellberg "" pour volume ordinaire)a été effectuée Ii la Falconbridge Ltd. , Division canadienne du nickel aux installations de Sudbury . Ces casques sont largement utilisés dans les mines de la Falconbridge Ii Sudbury.Cette étude aeu lieuen milieu de travail dans les quatre mines de la Falconbridge sous trois rubriques différentes soit: les données d'atténuation du bruit du fabricant (méthode psychophysique), la force de serrage et la taille de la tète (diamètre bizygomatique), et les essais d’atténuation de bruit (méthodes physiques). Les fabricants de dispositifs de protection contre le bruit prétendent que leurs produits offrent une réduction du bruit s'élevant Ii"

Jan 1, 1986

By François Robert, Rex Brommecker, Don S. Bubar

"The Orenada Zone 4 deposit is a small vein-type gold deposit occurring directly within the Cadillac Break southeast of Val d' Or in southeastern Abitibi Sub province. Mineralization is hosted by the Piche Group which, on the Orenada property, consists of talcchlorite- carbonate, chlorite-carbonate, and sericite-chlorite schists, derived from ultramafic volcanic, mafic igneous, and intermediate to felsic volcaniclastic rocks, respectively. All these rocks have been carbonatized.Rocks of the Pichi Group display a strong east-west, subvertical S1foliation, which is superimposed by asymmetric, intrafolial F2folds with shallow to moderate plunge to the east and to the west. F2folds are accompanied by an S2, subvertical axial planar cleavage, and are interpreted to result from dextral transcurrent shearing along sr.The Zone 4 deposit occurs within a large F2 fold, 60 m wide and plunging at 45 to the east, down to a depth of at least 300m. The auriferous zones consist essentially of zones of closely spaced, parallel quartz-tourmaline-albite-carbonate-arsenopyrite veins concordant to Sr these veins have been folded by the large F2fold and may pre-date the folding. A few discordant quartz-tourmaline-arsenopyrite veins, post- dating the F2 folding, also contain gold. Wallrocks adjacent to concordant veins have been carbonatized, albitized and contain significant amounts of tourmaline and arsenopyrite, with which gold is intimately associated.The Orenada Zone 4 deposit is a unique example of a deformed vein- type gold deposit, and exemplifies one of several types of association of lode gold deposits with folds."

Jan 1, 1990

Arguably the SMC Test® has become the most popular laboratory hardness test in the world with over 17,000 tests having been completed to date, covering over 650 different ore bodies. It is now routinely used in design, optimisation and orebody profiling projects. The test is unique in that from relatively small amounts of drill core it simultaneously provides parameters that are used in simulation modelling of AG/SAG and crushing circuits as well as work indices that are used in power-based equations for predicting the specific energies of AG/SAG/Crushing and HPGR circuits. The very large data base that has been accumulated has provided the opportunity to study the differences in variability from deposit to deposit. This paper describes and discusses the trends that have become apparent from the study of this data base. Recommendations for appropriate selection of sample numbers are also made which are based on these trends.

Jan 1, 2012

By H. J. McQueen

Aluminum was hot worked at 400 - 500°C and strain rates (e ) of 0.004 -0.1s-1, under reversing strains (c) of 0.5 to 0.2 or 0.5 to 0 and also advancing from 0.5 to 1 or 0.5 to 5. Under similar test conditions for different parts of the strain paths, the average measured flow stresses are found to agree with each other. In the forward and backward strain path tests, the almost identical steady state plateaus affirm the occurrence of dynamic recovery (DRV). On reversal of strain direction at constant e , there was generally negligible Bauschinger effect. In specimens annealed at 400°C, static recrystallisation (SRX) was followed microstructurally. mainly by disappearance of elongated grains with serrated boundaries because the new grains were only little a finer than the old due to low strain energy. The only influence of reversing strain path observed was the effect of change of grain boundary area as grains elongated or returned towards equiaxed. In optical microscopy, elongated grains with serrations and deformation bands confirmed DRV in forward path specimens. In reverse path specimens, equiaxed grains were gradually restored with retention of serrations and bands. In low magnification polarized optical microscopy, grain alignment increased with strain for forward path specimens; whereas it decreased in reverse path ones, supporting DRV. Orientation imaging microscopy (OIM/SEM) revealed that elongated grains are broken up as deformation bands rotate during the forward path and that grains return to equiaxed appearance on backward straining. Comparative studies using optical microscopy in polarized light (POM), OIM/SEM and transmission electron microscopy (TEM) revealed that while subgrains remain equiaxed and constant in size and character during the forward and backward paths, the fraction of low angle facets decreased while that of high angle grain facets increased with increasing strain; these are coupled with a fairly low fraction of medium angle boundaries. The results contribute to the understanding that dynamic recovery in aluminum maintains sub-boundaries with low misorientation but as grains elongate and more subgrain become adjacent to grain boundaries the fraction of high angle boundaries rises (with backward straining it was vice versa).

Jan 1, 2007

By K. Halada

Current trend of the global flow of strategic metals are analyzed to discuss the strategy of the development of recycling technology and alternative technology. In many cases, each global flow of metal is changing from the trilateral structure of U.S., EU and Japan in the later 20th century into the convergence to China as the factory of the world. Scrap flows are also changing dynamically. A long term change of prices of metal has gotten changed since the entrance of this century. The estimation of metal consumption up to 2050, in which the author estimated that many kinds of metal will overshoot the reserve base line, is revised considering these change of current trends.

Jan 1, 2014

By Hermann A. Derbuch

Twin Mining made a conscious decision when it changed from gold mine explorer and developer to become a diamond explorer in Canada?s Arctic. It was a decision of survival in an environment that saw junior gold companies either disappear or turn into dot com companies. Twin Mining learned fast and staked within weeks of that decision the first 50 sq. km of claims on, what became, its TORNGAT property at 59½° latitude on the east coast of the Ungava Bay in northern Quebec. This land position, 724 diamonds later (including 322 macro diamonds of gem quality, white and transparent) grew to 507 sq. km today. The 74° latitude called when Twin Mining exercised the option to acquire 3 claims owned by Helix Resources Inc. which revealed exceptional diamond potential. A gem quality 5.4 mm (0.768 carat white and transparent) diamond and the discovery of 16 pipes on 15.2 ha convinced Twin Mining?s board to sanction the deal. Both properties have outstanding features. Kimberlite Dykes and Pipes are in outcrop. The property locations have deep-sea access near existing infrastructure. Their locations are in an environment that is stable and development friendly and has a positive track record with successfully operating mines near-by.

May 1, 2001

By I. Farr, H. Wittens

"In 1989 and 1990 abnormally high levels of arsenic in ore from the Thompson Open Pit Mine threatened Manitoba Division's electro-nickel production. The paper will discuss our development of a flotation process to separate pentlandite and gersdorffite (the prime nickel and arsenic bearing minerals).The presentation will focus on the development of the process from conception, through lab and plant test work, to plant optimization and full scale production. The paper will conclude with the benefits and cost of the completed project.INTRODUCTIONRejection of arsenic from nickel sulphide ores was not a primary concern in the Manitoba Division until 1989. At that time increased production in the Thompson Open Pit mine, which contains high arsenic ore zones, resulted in excess amounts of arsenic in the Thompson Refinery affecting electro-nickel quality. This problem was resolved through extensive efforts by Mill personnel. The purpose of this paper is to familiarize the reader with- the Thompson Mill.- the mineralogy of the Thompson orebody.- the evolution of Ni/As separation in the Mill.- the metallurgical impacts of the separation on the Mill.- the importance of the separation to the Manitoba Division."

Jan 1, 1991

By Z. Huda

The effect of various percentages of cold-working and recrystallization on the microstructure and hardness of commercially-pure aluminum plate, has been studied. The 'A critical deformation for the aluminum, has been determined. Experimentation involved cold rolling and recrystallization processes followed by quantitative metallographic practice and the hardness measurements. The raw material chosen was a plate of commercial aluminum which was cold rolled to different percentage of cold-work and then recrystallized by heat treatment at 150°C. The critical deformation percentage of aluminum was computed to be around 30% of cold-worked.

Jan 1, 2007

By E. Burdukova

Rheological measurements have found a wide array of applications in mineral processing research. Rheological properties of mineral suspensions are highly dependent on the mineral surface properties as described by DLVO theory, and the relationship between these properties and inter-particle interactions is well established. In this paper, rheological properties of mineral suspensions are used to study the differences in behaviour of isotropic talc and anisotropic zirconia minerals as a function of varying properties of the suspension medium, such as pH and polymer dosage, specifically carboxymethyl cellulose (CMC). It was found that the rheological tests when carried out in parallel with electrophoretic or point of zero charge measurements, clearly reveal differences between behaviour of the suspensions of isotropic and anisotropic minerals. These differences are further accentuated with the addition of carboxymethyl cellulose (CMC).

Jan 1, 2006

By C. G. Anderson

Industrially proven and applied nitrogen species catalyzed (i.e. NSC) acidic pressure leaching has been utilized to treat a number of ores, concentrates and recycled materials. This versatile technology offers many advantages including low temperatures, low pressures, low capital costs, low operating costs, faster throughput and less costly materials of construction than conventional pressure oxidation. This paper will elucidate the application of this technology for production of gold, silver, palladium, rhodium, zinc, germanium, gallium, cobalt, copper and nickel. Recycled material applications will also be elucidated. In addition, details of an application for treatment of a refractory chalcopyrite copper and gold bearing ore will be presented and pertinent economics discussed.

Jan 1, 2004

By David G. Dixon, Ahmad Ghahremaninezhad, Edouard Asselin

"Atmospheric leaching of chalcopyrite in sulfuric acid solutions is a slow process due to the mineral’s passivation. We have investigated the nature of the passive film in this work. Electrochemical reduction and oxidation of chalcopyrite over the potential range of -0.5 to 1.2 VSHE were investigated in 0.5 M sulfuric acid solution (pH 0.3) at 25 ºC by multicyclic voltammetry and open circuit potential measurement. The influence of scan limits on the evolution of current peaks was studied with both stationary and rotating electrodes. It was observed that the anodic oxidation of chalcopyrite begins at potentials above 0.6 VSHE, most likely by preferential dissolution of iron atoms over copper atoms. The selective electro-dissolution process results in formation of a metal-deficient sulfide passive film (i.e. Cu1- xFe1-yS2, y > x). The passive film dissolves at 0.9 VSHE. Elemental sulfur is one of the products of chalcopyrite dissolution above 1.0 VSHE. Cathodic reactions within the potential region of 0.1 to 0.6 VSHE and anodic reactions at potentials lower that 0.5 VSHE are associated with at least one soluble species from solution. The soluble species involved in the cathodic reactions are likely ferric and cupric, while the soluble species involved in the anodic reactions is likely H2Saq."

Jan 1, 2014

By S. C. Ellis

THE bituminous sand of northern Alberta has already an extensive literature, and most of the reports dealing with the subject are still available (see Selected Bibliography at end of paper). A phenomenon so striking and, as regards its extent, so unique, as the deposit in the vicinity of McMurray settlement could not fail to attract the notice of the early explorers, and we find references to it as far back as the latter part of the eighteenth century. However, scarcely a thought had been bestowed upon the possible economic value of minerals in the the remote northern parts of Canada before the second decade of the present century, and practically no detailed mapping had been done north of the town of Athabaska. The late Wm. Ogilvie made a track survey of Athabaska river in 1884, and surveys of certain lines-including the 23rd base line-had been completed by 1911. Between this base line and lake Athabaska, nothing had been attempted. Actually, no definite information at all was available regarding the character and extent of the bituminous sand when, in the earl y summer of 1913, a reconnaissance party set out from Athabaska for McMurray. At that period, the journey was made in summer by scow or canoe. No telegraph line had been laid, and a casual mail service by canoe or dog team once in three months formed the only means of communication with the outside world. The investigation has begun by the Mines Branch was continued during several subsequent years. The sand deposits were studied and sampled, the bi rumen was extracted from the sand and studied chemically and physically, and the economic significance of the deposit was given exhaustive study.

Jan 1, 1937

By J. A. Morgan, P. M. Dimmell

Abstract - The Aubry pegmatites are located on the Seymour Lake property, 15 km north of Lake Nipigon in northwestern Ontario. The property lies within the Caribou Lake-Marshall Lake greenstone belt along the English River-Wabigoon subprovince boundary of the Superior province of the Canadian Shield. The property was optioned in March 2001 by Linear Resources (now Linear Gold Corp.), who carried out gridding, prospecting, geological mapping, soil and lithogeochemical sampling, trenching, channel sampling, and a total of 1,866 m of diamond drilling in 32 holes. The Aubry pegmatites are classified by Breaks et al. (2003) as complex type, spodumene-subtype, lithium-cesium-tantalum pegmatites (Cerný, 1989). These pegmatites generally form under high-pressure-low-temperature conditions, display complex internal zoning, have relatively low Nb/Ta ratios in the ore-forming assemblages, and contain significantly elevated tantalum values (Cerný, 1989). Other examples of spodumene-subtype pegmatites include the formerly producing Hugo pegmatite in South Dakota, and the currently producing Greenbushes pegmatite in Australia. The Aubry pegmatites occur as an undulating system of stacked sheets that dip moderately to steeply eastward over a 1-km strike length. The main portion of the North Aubry pegmatite ranges in true thickness from 10 to 28 m over a strike length of 125 m, whereas the thickest portion of the South Aubry has an estimated true thickness of 15 to 16 m over a minimum strike length of 95 m. The North Aubry pegmatite remains open downdip and along strike to the north, whereas the South Aubry pegmatite remains open downdip and along strike in both directions. The Aubry pegmatites are among the most highly evolved in Ontario, with the southern end of the North Aubry (trench 5/6 area) being the most highly fractionated (Breaks et al., 2002). Channel samples from the trench NA-5 area of the North Aubry pegmatite produced values up to 2.49 wt.% Ta2O5 over 4 m. Coarse manganotantalite crystals, up to 5 cm in diameter, from this trench contain up to 84.9 wt.% Ta2O5 (Breaks et al., 2002). Drill hole SL02-31 in the trench NA-6 area gave values of 0.046 wt.% Ta2O5 over 17.7 m, including 1 m @ 0.464 wt.% Ta2O5. Further exploration will focus on defining the grade of the North Aubry zone, extending and defining both known pegmatites, and identifying additional Ta-rich zones within them. Lithogeochemical and enzyme leach soil geochemical data suggest the presence of multiple undiscovered pegmatites on the property.

Jan 1, 2005

By Pascal Turcotte

_ Introduction _ LaRonde _ Controlling Instability in Haulage Drifts _ Failure mechanism in drifts walls _ Failure mechanism in drifts back _ Field Behaviour of Support Elements _ The ?Hybrid Bolt? _ Conclusions

Feb 1, 2008

The comminution circuit at Tarkwa Gold Mine was commissioned as a Single Stage SAG mill operated in closed circuit with hydrocyclones designed to process 4Mtpa. The circuit was later expanded by adding a secondary ball mill in closed circuit with hydrocyclones with a view to treat 12Mtpa. The change in the circuit configuration and assigning the low aspect ratio SAG mill for primary grinding application makes the Tarkwa experience unique in terms the optimisation strategy and operating philosophy. This paper reports the findings from a series of surveys performed on this plant. The surveys reported include data obtained when the SAG mill was operated as a single stage mill in closed circuit with hydrocyclones and also SABC mode under two different feed conditions. The differences in operating philosophy between the initial single stage SAG circuit and the current SAG/Ball mill circuit are discussed.

Jan 1, 2012

By G. Mousavian, R. Bagheri, N. Dalili

Polypropylene (PP) and its composites have an increasing use in automobile and domestic industries. Since the published results on strain rate effect on yield behavior do not match, and there is a high attention paid for effect of nanometeric fillers on deformation behavior of composites, in this research the strain rate effect on yield behavior of PP and the effect of nanometeric fillers on deformation behavior of PP have been studied. Microscopic observations and tensile tests in different strain rates on neat PP samples and on samples filled with 5, 10 and 15 %wt have been used. A dramatic change in behavior for the modulus and post-yield slope curves when the strain rate is between 0.0433-0.05 s-1 has been observed. Microscopic observations on PP indicate a change in deformation mechanism from shear yield to crazing at the same strain rate that the change in behavior of curves occurs. It has been observed that in PP nanocomposites with higher amount of calcium carbonate, fracture in early stages of deformation occurs in lower strain rates. In other words for a fixed stain rate there is a critical filler percentage such that if the filler percentage is higher then early-stage fracture will occur. Similarly for a fixed filler percentage there is a critical strain rate and in higher strain rates early fracture will occur. The critical stain rate will decrease as the filler percentage increases and vice versa.

Jan 1, 2006

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The use of large AG/SAG mills in the mineral industry has been on the rise recently due to a significant reduction in the capital and operating costs for achieving significant increases in plant throughputs. The major reason for downtimes in these mills is the time taken for the replacement of broken or worn liners. This loss of “availability” of these units has a significant impact on the productivity of these plant operations. The ability to predict liner life time and its evolving shape could help to optimize these comminution operations. In the past decades, various models have been proposed to estimate liner wear rate, but because of their empirical nature they could only be used within certain limited operating conditions. In this research, a phenomenological model which could predict the liner wear rate was proposed and tested. This model considers parameters such as; operating conditions, liner hardness, pressure on the lifter, and, relative velocity of particles and mill shell. Data from industrially measured liner profiles were taken during the liner life time at the Sarcheshmeh and the Gol-E-Ghohar SAG mills to provide a solid base to calibrate and validate the model. The comparison of the model predictions with the actual measurements of the liner wear rate showed that the results were in a good agreement at both, the Sarcheshmeh (R2=0.94), and the Gol-E-Ghohar (R2=0.97) concentrators.INTRODUCTIONAG/SAG mills are one of the most important technologies in the mineral processing industry in the recent decades. The “Availability” of these units in a plant operation is one of the most important economic parameter for evaluating their performance. The major reason for the downtime of these mills affecting their “availability”, is the time required to change worn or broken liners (Yahyaei, Banisi, & Hadizadeh, 2009; Maleki-Moghaddam, Yahyaei, & Banisi, 2012). The knowledge about the magnitude and profile of liner wear not only enables more accurate liner life estimation to prevent unwanted interruptions of the SAG milling in mineral processing plants and more strategically plan the scheduled mill outages for liner changes. It also could provide key information needed to select an appropriate liner design (Yahyaei et al., 2009; Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010a)."

Jan 1, 2016

This paper outlines the position and capabilities of Western Canada's bituminous coal industry, and indicates the increasing importance of Japan as an export market. The use of coal in Japan is reviewed, especially as regards future trends, and an appraisal is made of Canadian coal in comparison with domestic Japanese coal and imports from other countries. The importance of maintaining a solid nucleous within the Canadian bituminous coal industry is emphasized. I N RECENT years, Japan has emerged as a valuable market for Canadian exports. The first major product exported in volume to Japan was wheat, which has become very successfully established in Japanese markets. Following this, iron ore gradually found a market in Japan, with exports usually based on long-term contracts. This iron ore was produced entirely in British Columbia In 1958, the Western Canadian bituminous coal industry -jointly with the Dominion Coal Board -sent an official mission to Japan to investigate the

Jan 1, 1964

By L. Veleva, Garcia. A., G. Perez

Aluminum is a metal used for the transmission of electricity of high voltage, in the construction industry and other areas. In atmospheric conditions aluminum forms an oxide layer (Alz03'H20) as a result of its corrosion, entering the passive state. The oxide layer can be destroyed by the presence of ions (Cr, SOx-n) developing localized (non uniform) corrosion attack by pitting, difficult for evaluation. The concepts of fractals and self-similarity were used in this study for the characterization of the development of localized corrosion. Images obtained with a scanning electron microscope (SEM) of samples of electrolytic aluminum wire that have been exposed during one year in ruralurban and marine-coastal environments of the humid tropical climate of Mexico, have been processed. The development of pitting has been studied as a function of time, making a statistics of the frequency of appearance of pits versus the area occupied by them. The data show that the distribution of the pits follows a power law. Therefore, the concept of self-similarity can be applied for the study of the phenomenon of localized corrosion, describing their development with time.

Jan 1, 2006

By John C. Luck Jr.

"DEVELOPMENT of oil emulsion mud dates back to the early days of rotary drilling when oil was added to the drilling mud solely for the purpose of freeing stuck drill pipe. After the drill pipe was freed, and drilling resumed, this oil was considered a contaminant. Efforts were made to remove the oil but some of it remained and was emulsified with the drilling mud, thus forming a mechanical emulsion.During the late 1930's, operators found that adding crude oil to drilling muds seemed to alleviate 'sticky-hole' problems and so oil was allowed to remain in the mud. This practice was adopted when it was found that faster drilling rates and longer bit life were obtained. These observations led to the development of emulsion drilling muds. During the past five years their application has become more widespread because of the lower fluid losses obtained, greater lubrication qualities, faster penetration rates, and generally better hole conditions.An emulsion may be defined as a two-phase system consisting of a mixture of either finely divided oil droplets in water or of finely divided water droplets in oil. The surrounding liquid is known as the continuous phase. The emulsifiers reduce the interfacial tension, making the droplets tend to repel each other so that they remain dispersed and stabilized. These emulsions are classified as oil-in-water or as water-in-oil, depending upon whether water or oil, respectively, is the continuous phase. Briefly, close inspection shows that they consist essentially of globules of• the one liquid suspended in a continuous mass of the other liquid. Oil emulsion muds are usually of the oil-in-water type. Two basic types of emulsifiers •commonly used in Canadian muds are soaps and lignites."

Jan 1, 1954