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By M. Piard

Fires and explosions are not likely to originate in clean gobs above pillar faces steadily driven through a solid panel in order to effect a complete extraction. As. to the storage which such a process implies where the market is intermittent, its cost will never equal that of abandoning large pillars in a fully developed property. Much less will that cost, thanks to the big sizes obtained, ever approach that of cleaning wet and dirty crushings robbed at great expense from small pillars exposed to many years of roof pressure. Even thick seams under bad roof may be fully extracted without the help of filling material. Fatal accidents from falls of roof owing to the great height of excavations, losses in coal, and the danger from fire, have compelled operators in South Staffordshire, England, to discontinue the stall-and-pillar system at one time supreme in the district, and to successfully adopt the following plan: A retreating' longwall is run along the top coal, as the first working; the bottom coal is taken in the same manner, after the fallen roof has become sufficiently consolidated to allow the mine to be reopened. A similar plan is suggested in this paper in order to deal with the outcropping and pitching seams found in the Kootenay measures.

Jan 1, 1930

By N. Maleki

In recent years, research and development of magnesium alloys have been greatly promoted by the lightweight requirements in critical industries. The use of these alloys, however, has been restricted by their limited mechanical properties especially at high temperatures. The disadvantages can be overcome by producing Mg matrix composites. The Mg?Si alloys containing in situ Mg2Si particles have found a great potential as structural materials. Unfortunately, Mg2Si compounds are prone to form undesirable coarse Chinese script morphologies, which would deteriorate the properties of the materials. Refinement of microstructure is performed for improvement of wear and corrosion resistance. This paper investigates the microstructure and corrosion behavior of pure magnesium, unmodified and modified magnesium matrix composites reinforced with Mg2Si particles. The Mg2Si/Mg composite was prepared via a normal cast route, and then various amount of zinc was added to melt in order to modify the Mg2Si reinforcement particle morphologies. The microstrucrures were characterized by optical and scanning electron microscopy followed by EDX analysis. The corrosion behavior of Mg/Mg2Si composite was investigated by using potentiodynamic polarization measurements. The results showed that by addition of zinc, the average size of the primary Mg2Si became significantly decreased from about 100µm to about 20µm, as well as its morphology changed from dendritic to a polyhedral shape. However, by adding extra amount of zinc many primary Mg2Si particles become coarse again. It was also found proper amount Zn addition increased the corrosion resistance of Mg/Mg2Si composite.

Oct 1, 2011

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

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

Jan 1, 2004

By Murray D. Fredlund

The consolidation of soil material is central to many types of engineering analysis. Problems such as the building of highway structures, landfills, or buildings over saturated soft clays require application of such theory. It has been found in industry that the application of consolidation theory has lagged significantly behind the theory which has been developed some time ago. The application of small-strain saturated consolidation theory was first proposed in a 1D form by Terzaghi. Although this theory has been available for some time it?s implementation into software packages in 2D and 3D forms has been slow due to inherent complexities in the coupling equations. The flow and stress equations are also inherently somewhat unstable and this further complicates software implementation. Of particular interest in the mining industry is the consolidation of uranium tailings. One such disposal method that has been utilized is the subaqueous deposition of uranium tailings in large pit structures. When performing such deposition the calculation of consolidation rates is central to determining final pit capacity and expected life. Consolidation software can be successfully used in such cases in order to determine pit filling rates. The primary complexity, however, is that tailings are typically deposited in slurry form and therefore the potential deformations are large. Large-strain consolidation theory is therefore required in order to properly solve the deformations over time. This paper presents the use of a large-strain consolidation analysis in order to predict long-term filling rates in a uranium tailings pit.

Aug 1, 2010

By Gordon R. Peeling

The Problem Five years after the consensus of the Whitehorse Mining Initiative the industry was losing public confidence Public opinion surveys ranked mining just above the tobacco industry Project opportunities were being lost to public and political opposition Operating practices called into question by a number of tailings dam failures CBC broadcast of "The Ugly Canadian" Our social licence was being lost

May 1, 2013

By Tom Setterfield

Monster Copper Resources ?Junior focused solely on IOCG deposits ?Founded by ex-WMC geoscientists ?Properties in Brazil, Wernecke Breccias (Yukon), Central Mineral Belt and Nova Scotia Nova Scotia ?JV with Wallbridge Mining Company ?Ongoing Story ?Presented as a case study in generation and implementation of IOCG exploration program

Apr 1, 2005

By S. Afshar, E. Dajoux, C. Allaire

For various reasons, molten salts, mainly chlorides and fluorides, are used in the aluminum industry. In the holding and melting furnaces, these salts may have different roles such as protecting the metal from oxidation, reducing the metal content of the skim or removing inclusions or impurities from the metal bath. However, the use of these salts may also have some undesirable effects such as easy attack of the furnace lining refractory materials by molten aluminum. The aim of the present investigation was to clarify and to compare the effects of chloride versus fluoride salts, on the corrosion process of the aluminosilicate based refractory materials. A laboratory test and procedure, simulating the conditions at the metal line in the aluminum treatment furnaces, was used. Different aluminum alloys (A1-5wt.%Mg, A1-5.5wt.%Zn and 7075 alloy) and chloride or fluoride salts (MgC12, KC1, CaCl2, NaC1, MgF2, CaF2, NaF and cryolite) were used as well as several aluminosilicate materials. Thermogravimetric measurements were also carried out in order to analyze the effect of the salts on the oxidation of molten aluminum alloys. The experimental results showed that fluoride salts are more aggressive than chlorides against the tested refractory products. It is postulated that the fluorides prevent the formation of a protective oxide layer on the metal surface, favoring at the same time the corrosion of refractories. Moreover, it was found that the presence of Na in fluoride salts increases significantly the aggressiveness of the aluminum alloy towards the refractory samples.

Jan 1, 2004

By W. E. Johnston

At last year's Annual Meeting a paper by Haultain and Johnston was presented entitled Is the Gold in Tellttrides Soluble in Cyanide? Since then the writer has continued the study of various phases of this problem. Samples and specimens of ore from some of the Kirkland Lake mines have been studied and non gold-bearing tellurides have been found in these that are not soluble in ordinary mill solutions. Samples of tailings, both old and recent, from this district have been examined with apparatus and methods that have proved very successful in detecting the presence of extremely minute quantities of tellurides. Tellurides, both base-metal and gold-bearing, have been discovered in these tailings, but only in such minute quantities that their presence would not affect the ordinary assay results. More free gold particles have been found in the tailings than gold-bearing tellurides. Much experimental work has been done on tellurides, concentrated from high-grade material and from ordinary run-of-mine ore. The gold-bearing tellurides behave very much as does gold itself. Finely divided particles are dissolved fairly rapidly, coarser particles more slowly. All the tellurides are soft and brittle and also have a high specific gravity, with the result that they are extremely finely divided in ordinary mill practice. The ordinary high-lime solution of Kirkland Lake practice is suitable for the dissolving of the gold tellurides. Oxygen is necessary, but apparently not more so than in dissolving gold. Some particles have been found that appear under the microscope to be ordinary metallic gold particles, but on heating they show a small telluride content. These appear to dissolve more slowly than gold. There is considerable variation in the ratio of tellurides to gold from different points in the mines. So far the writer has failed to find any connection between this ratio and the richness of the ore. Generally speaking, the base-metal tellurides predominate. Some of these contain gold but this may be due to a mixture of tellurides in the one particle.

Jan 1, 1933

By Bryn Harris

Answer to the question is given as 42! Asked the wrong question So got the wrong answer How does this apply to the mining industry? And particularly to this session on Water? Water is just one aspect of mining/minerals/metals Should not be looked at in isolation Need to adopt a ?holistic? approach

May 1, 2013

By N. Maleki

Magnesium matrix composites are widely used in automotive and aerospace industries for achieving higher performance due to their light weight. The Mg2Si intermetallics compound in Mg/Mg2Si composite exhibits many excellent properties such as high melting temperature, high hardness, and low thermal expansion coefficient. However, under normal cast conditions, the primary Mg2Si phase exhibits coarse Chinese script or dendritic morphologies and the eutectic structures is very brittle resulting in the low ductility and strength of the alloys. Modification treatment is a very effective method to obtain fine microstructure and improve the mechanical properties of the alloys due to low production cost. In this investigation various amount of bismuth addition have been carried out on Mg?5wt %Si alloy to refine and modify the morphology of coarse Mg2Si in order to improve the corrosion resistance of the composite product. The effect of Bi content on microstructure of Mg2Si/Mg composite was investigated by optical and scanning electron microscopy followed by EDX analysis and X-Ray diffraction. In order to compare corrosion resistance of unmodified and modified specimens, Immersion test and potentiodynamic polarization (PD) were used. The results showed that by Bi addition, the size of primary phase Mg2Si was considerably reduced and the morphology was modified from a coarse dendritic shape to a polyhedral shape. The results also indicated that the corrosion resistance of Mg?Si alloys was improved by the addition of 1%wt of Bi due to the reduction, refinement and evenly distribution of Mg2Si phase. Indeed, both the morphology and distribution of Mg2Si intermetallic had a great influence on the corrosion behavior of Mg/Mg2Si composite.

Oct 1, 2011

By Michel Noël

This paper presents a partial compilation of adopted measures of waste rock dump closures at mine sites located in Canada and Alaska, where the climate includes cold winters. The paper also presents the selection process that was followed for some of those mine sites. Mining operations usually generate waste rock that can sometimes result in very large quantities. Additionally, the nature of the ore body and the host rock will often introduce environmental impacts. These impacts need to be managed not only during the operations but also in the long term. Mine closure plans consequently have to address the long term issues that sometimes require perpetual treatment. Closure planning often involves the evaluation of risks associated with environmental and financial liabilities. It needs to consider the science, some common definition of objectives, and there will be a need to manage resources and schedules. Closure planning is essentially an exercise in constrained decision making. A performance and risk based ranking matrix is often developed during this selection process to identify the preferred option(s). The case studies presented in this paper provides a few examples. The level of knowledge on acid rock drainage from waste rock dumps has increased considerably over the past decades. It did not necessarily increase the level of complexity of the adopted closure methods, as the selected closure methods are often kept simple. A common approach consists of stabilising the slopes of the waste rock dumps material by resloping and then covering the waste rock with a growth media to support vegetation. Such covers prevent direct contact of animals with the waste rock material, minimise erosion and reduce infiltration to various degrees. The inclusion of water treatment is obviously dependent on the water quality being released.

Nov 1, 2008

By T. I. . I. Sibbald, D. E. Jiricka

The Goldfields area on the north shore of Lake Athabasca , was active in the thirties and early fortie . In 1934, Tom Box discovered gold mineralization in quartz veins in pyritized 'granite' at the ite of what wa to become the Box Mine of the Consolidated Mining and Smelting Company of Canada Ltd . In the rush of activity that followed numerou other gold occurrences were found. the most significant of the e being the Athona and Frontier prospects which underwent underground development bur did not reach production. Probable reserve identified to date in the Box and Athona deposits amount to some 3.5 million ton grading an average 0.ITT oz gold/ton . Some 10 to 15 million tons of lower grade, po ible reserve are also reported at the Box. From 1939 to 1942, the mine produced, from underground , 64,066 ounces of gold from ore grading 0.0452 oz gold/ton at a cost of between $1.5 and $2.0 a ton. The Goldfield area is underlain by upracrustal rock intruded by mafic bodies and invaded by ·granite'. The upracru tal . thought to be of Lower Proterozoic age are characterized by a helf-type ucce ion metamorpho ed under lowermiddle amphibolire facie conditions into quartzites, quartz-mica chi ts. dolomitic marbles, diop idic calc-silicates and cordierite-anthophyllite-biotite schi t . Amphibolites of presumed igneou origin form concordant to subconcordant units up to a few ten of metre thick in the upracrustals and occur as le regular masses in the 'g ranite·. Compositionally they vary from gabbroic to granodioritic. with the more mafic varieties being most common. Granitic rocks exhibiting a variety of textural , structural and compositional characteristics underlie most of the area. Four main units are recognized: foliated (older) 'granite', 'leucogranite', feldspar augen 'granite· and pyritic mine 'granite', however, in geological mapping the e are somewhat arbitrarily differentiated due to transitional relationships and admixture of types. Although there is no unambiguous age data available for the e 'granite ' adjacent northshore 'granite' of geologically similar age yield Rb-Sr isochron dates around 2000 Ma. The area is characterized by two major deformation events of which the earliest gave rise to the dominant regional foliation and to rare minor and outcrop scale folds. This foliation which in general parallels compositional layering is folded into the major Goldfields syncline, whose axis plunges weakly to moderately outh. Related open minor folds have subvertical axial surfaces which are locally paralleled by a weakly defined schistosity. Most rock display a pronounced rodding fabric, coaxial with second fold axes and apparently the product of this deformation event. However, a note of caution is introduced into this interpretation, as the rodding fabric is also parallel to first fold axe .

Jan 1, 1986

By T. Eger

Load Haul Dump vehicles (LHD) are extensively used in underground mining however equipment design and operating conditions contribute to restricted operator?s visibility. The inability to clearly see people, objects or hazards around the machine has contributed to a number of accidents including fatal injuries. In order to identify vehicle design characteristics resulting in restricted and blocked sightlines visibility assessments are traditionally completed in the field. However, field methods are unable to evaluate visibility under dynamic operating conditions and are limited in their ability to provide feedback on the impact of various operator characteristics such as sitting height, for example. Results of this research show computer simulation and virtual reality can be successfully used to evaluate visibility during the operation of LHD vehicles. In order to benefit from virtual reality applications the work environment, LHD vehicle and human posture need to be represented as accurately as possible. A computer simulation program with ergonomic ana lysis features, Classic JACK 3.1, was successfully used. Threedimensional CAD models of LHD vehicles were developed from manufacturer specifications and pictur es taken from LHD vehicles currently in use. The LHD models were imported into the JACK environment, a digital human was positioned in the cab of the LHD vehicle and the vehicle and human where driven over a typical mine route. Real-time feedback in the JACK program was used to identify what the operator could see under different operating conditions. Machine characteristics and operating scenarios resulting in impaired visibility were successfully identified with this method. The JACK program can also provide real-time feedback on the human?s joint forces and torques, strength requirements, postural comfort, and metabolic energy expenditure. As a result, this method could be used to successfully evaluate musculoskeletal injury risk factors along with system design recommendations to improve workplace safety and productivity in any setting. The LHD VRML files imported into JACK have also been combined with environment files into other VR software packages (e.g. Maverik) to view in a VRL facility, managed by MIRARCO at Laurentian University. The VR models using these packages can be viewed in stereo to provide better appreciation of spatial visibility issues.

May 1, 2003

By Linruo Zhao, Qi Yang, Akihiro Sato

TiN coating has a wide range of tribological applications from wear reduction of cutting tools to erosion protection of gas turbine engine compressor components. The performance of TiN coating depends on its microstructure, mechanical properties and adhesion strength which are influenced by the coating deposition process. In this study the effects of cathodic arc deposition conditions on the microstructure, hardness, adhesion and erosion resistance of TiN coating were investigated experimentally. It was found that varying deposition temperature, substrate bias and N2 pressure could derive a processing window in which TiN coating with superior erosion performance can be fabricated.

Jan 1, 2010

By Geoff Goodyear

UHNL Corporate Profile ? Providing Helicopter Services since 1963 ? A Newfoundland Company head-quartered in Goose Bay, Labrador ? Operations, while primarily Atlantic Canadian, extend across Canada, the Arctic, Greenland ? 16 aircraft, all single engine / VFR Typical Industry Mission Profiles & Work Environments ? Types of missions include: ? Air Taxi & Executive Transport ? Mineral Exploration ? Forest Fire Suppression ? Medivac ? Wildlife Management & Research ? High Angle Rescue and Ice Blasting ? External Load & Long Line ? Mountainous Terrain Operations ? Aerial Application ? Power line Patrols & Construction The Helicopter ? Essentially the same aerodynamic principals as fixed wing but with some mechanical variations on the theme

May 1, 2001

By René Dufour

Jusqu?à son acquisition par MM René Dufour et Alain Robin en 1994, les claims miniers et les droits de surface de la propriété étaient détenus depuis 1953 par la société Québec Columbium, une filiale de la socité américaine Kennecott Copper qui y a réalisé d?importants travaux miniers. En 1995 la compagnie NIOCAN inc. fut incorporée; ses actions furent inscrites à la bourse de Montréal en 1997, et à la bourse de Toronto en décembre 1999. Jusqu?à maintenant, NIOCAN a investi plus de 7 millions de dollars dans le développement de sa propriété minière de niobium située à quelques 40 kilomètres au nord-ouest de Montréal. Le haut rendement économique des deux gisements principaux que compte exploiter la compagnie, le S-60 et le HWM-2, a été établie par des études de faisabilité effectuées par le consortium Met-Chem/SNC-Lavalin. La mission que s?est donnée NIOCAN inc. consiste à mettre en production ses deux gisements et à devenir ainsi productrice de ferroniobium dans les plus brefs délais. Figure 2 Le projet est présentement à un stade avancé d?obtention du certificat d?autorisation du ministère de l?Environnement. À plus long terme, la compagnie compte aussi exploiter les sous-produits de ses gisements (apatite, forsterite, magnétite, calcaire et terres rares).

May 1, 2003

By T. G. Joseph, M. Welz

ABSTRACT: Joseph (2002) introduced passive seismic monitoring to measure mining equipment performance. This paper evaluates the potential of passive seismic monitoring to correlate mining equipment operation with oil sands surface response, with a mining hauler as the seismic source. When applied to moving haulers, this action–reaction approach is complex. Vibrations from on-board equipment, such as pumps and tires, dirty the signal with noise. To facilitate any correlation, the signal must be cleaned up. Existing geophysical analytical techniques were manipulated to evaluate the noise problem and to filter sufficiently to permit an evaluation of whether a mining equipment action–ground response relationships in fact discernable.

Jan 1, 2011

By John Crusius

? 3-year research program overview ? initial results- MainZone pit Waterline pit ? questions raised ? increasingly common in western N. America ? frequently low-pH waters with elevated concentrations of many metals ? water quality controls poorly understood ? some in U.S. are Superfund sites

May 1, 2002

By D. L. Johnston

"The avenues and degree of participation by aboriginals in the Canadian minerals industry have changed significantly during the thirty years of the author's career in that industry.The typical 1950s cycle of mineral industry involvement of a local non-Europeanized aboriginal was as an individual employee. The employment relationship would begin with the best of intentions by both parties of permanence and terminate when the pioneering employee was unable to reconcile the attendance behaviour required by the employer and the social-sharing behaviour demanded by family and friends.Cominco Ltd. has been a mine operator and developer in the North since the 1920s. Cominco's early experiences with employment of non-Europeanized natives at the Con Mine in Yellowknife, Northwest Territories from 1938 to 1986 was a negative experience from both the employee and employer ends. A series of classic failures in employment of individual aboriginals was a large part of the history. A few Metis or natives from other areas were the permanent aboriginal employees at Con (2010). Racial prejudice was overt on the street in Yellowknife and, it can be assumed, in the workplace, as well.The history of aboriginal employment at the Pine Point, Northwest Territories operation (1964 to 1988) was somewhat better but also frustrating. The mine was equidistant (80 km) from the Dene communities of the Hay River Indian Reserve and Fort Resolution, both on Great Slave Lake. Despite a large aboriginal presence and many well-intentioned efforts, employment of aboriginals at Pine Point never got much beyond ten per cent. These would have been half local and half northern prairie aboriginals. One continuing success story was the railcar loading and covering crew led by Ed McKay, a local aboriginal. This predominantly aboriginal crew did its own recruiting and several are on Cominco pension."

Jan 1, 1995

By Tom Shumka

All mineral processing facilities that use girth gear driven mills need to inspect the gear teeth on a routine basis, whether it is every six months or every three years. The inspection frequency depends upon gear tooth condition, and the objective is to ensure operational integrity of the gear teeth. Conventional methods such as magnetic particle testing, visual inspection, or dye penetrant examinations rely heavily on interpretation. At best, these techniques can determine whether a defect exists, but are unable to provide information on defect severity. This paper describes the use of combined Eddy Current Array (ECA) and Alternating Current Field Measurement (ACFM) to provide a complete survey of all surface breaking indications on the whole gear tooth depth. This method accurately determines the size, length and depth of any cracks found on the surface.

Jan 1, 2012