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By F. Chiesa

Experimental results on thin and thick castings poured in aluminum A356 and magnesium AZ91E by the low pressure permanent mold process have been compared to the result of filling simulations for thin and thick castings. If the results of modeling is reliable when the liquid remains above the liquidus temperature, this is no longer the case when partial solidification occurs. The visco-elastic behavior of a partially solidified liquid is difficult to put into equation as it depends on the amount of shear it has been been subjected to. Attempts to predict misruns with a commercial software has been proven to be very difficult if not impossible; divergence of the numerical solution has been observed unless prohibitively long computing times are used. In order to overcome these difficulties from a practical standpoint, a simple method is proposed which consists in tracking the temperature of the advancing liquid metal front so as to make sure it will always be above so-called `Misrun Critical Temperature' (MCT) determined experimentally for thin and thick aluminum A356 and magnesium AZ91E castings. If the liquid metal front falls below this temperature, a cold-shut or misrun is likely to happen at this location. The values of MCT for thin and thick in aluminum A356 and magnesium AZ91E were determined experimentally on misrun castings of extreme geometries (a thin 2.5 mm wall cover and a 6mm to 25 mm thick bell housing). MCT was found to be lower for magnesium AZ91E and for the thicker castings.

Jan 1, 2011

By J. Fellowes, V. Landais, J. Robson, J. Carr

"Aerospace Al-Zn-Mg-Cu (7xxx) alloys are known to be susceptible to environmentally assisted cracking (EAC). This phenomenon has been studied intensively for many decades, leading to empirically adopted methods to mitigate this problem through overaging and composition design. In parallel, many theories have been developed to explain EAC in 7xxx, but none is yet universally accepted. Today, a number of emerging techniques offer potential to shed new light on EAC in 7xxx. The purpose of the present paper is to demonstrate how X-ray tomography (XCT) combined with electron microscopy can be used to identify the true crack path in 3-dimensions, and hence identify material for site specific electron microscopy analysis. Composition mapping over large areas to high accuracy has been performed using a modern electron microprobe analysis system. This has been combined with transmission electron microscopy to investigate local composition in matrix and precipitates at high resolution. This combination of techniques across length scales offers the potential to provide new insights into the links between local composition, microstructure, and EAC resistance.INTRODUCTION Environmentally-assisted cracking (EAC) is a phenomenon which dramatically decreases the performance of metals and can cause premature failure of large structures. Observed in situations where components were not subjected to critical loads and no widespread corrosion was involved, this type of brittle failure is extremely difficult to predict. The EAC designation covers a number of phenomena, e.g. stress corrosion cracking (SCC), hydrogen embrittlement (HE), corrosion fatigue (CF), etc. Initially identified in steels, EAC can also affect other metals such as high-performance aerospace aluminium alloys, and this phenomenon has been a concern for industries for decades. Extensive research has been conducted on the effects of various environments (moist air, saline water, dry hydrogen gas, etc.) on microstructures and crack propagation, however no consensus has been reached and the exact nature of the mechanisms that control EAC is still being debated (Birnbaum & Sofronis, 1994; Gangloff, 2007; Holroyd & Scamans, 2013; Lynch, 2012; Oriani, 1972; Scamans, Alani & Swann, 1976, Young & Scully, 2002)."

Jan 1, 2018

By Muhammad Zaka Emad

ABSTRACT: Sublevel stoping mining methods with delayed backfill employs cemented rockfill (CRF) as a backfill material. It is used in underground mines to achieve ground control and reduce wall slough. In addition CRF serves to reduce development waste and provides a working surface for mining the upper levels. Efforts to optimize CRF practices have been published. This paper presents a detailed review of CRF practices in open stoping mining systems with reference to case studies. A new methodology is suggested in a simple stepwise approach, which can be adopted for site specific conditions. The need of laboratory testing and quality control program is discussed based on the published literature.

May 1, 2013

By I. M. R. Duarte, J. A. Rodrigues-Carvalho, F. R. S. Rosa, A. B. Pinho

"This paper aims to contribute to the knowledge of the mechanical properties of the shales and greywackes which constitute the flysch-type deposits of the Baixo Alentejo Flysch Group, in the south of Portugal. These formations are flysch-type deposits constituted by sequences of usually thick greywacke beds alternating with thin shale beds, which include sometimes intercalations of conglomerate beds. All the sedimentation of these flysch formations was controlled by tectonics. At the same time, should have occurred along with the first Hercynian deformation phase, a low-grade metamorphic event (chlorite zone), that affected these flysch deposits. This study highlights the influence of anisotropy and heterogeneity of these flysch rocks on their physical and mechanical characteristics. The anisotropy verified in some physical properties and on mechanical properties, due to the foliation makes difficult the sample preparation for the laboratory tests. Besides, it induces a scattering of the properties values measured, as for example, the strength and the deformability. The heterogeneity is related to the main features of these geological formations, which are constituted mostly by thinly stratified greywackes and shale beds, which sometimes may affect the results of the laboratory tests making them less representative. The study is made by using both shales and greywackes that constitute these flysch-type deposits in order to evaluate their geotechnical properties, mainly of the shales. Samples of these two rock materials, are tested accordingly a laboratory testing programme, which includes which included mineralogical analysis (X-ray diffraction), physical tests (bulk density, porosity, and void index) and mechanical tests (uniaxial compression, and deformability tests). INTRODUCTIONOne of the factors that most influence the geomechanical behavior of rocks, as well as rock masses is the anisotropy. The word anisotropy comes from two Greek words ""anisos"" (meaning uneven) and ""tropos"" (meaning direction). A body or material is considered to be anisotropic, where the same property has different values depending in which direction it is measured, therefore, an anisotropic material is one whose magnitude of the properties depends on the direction in which these are studied or measured. Otherwise, it is about an isotropic material. However, the fully isotropic materials are quite rare in nature."

Jan 1, 2015

By Glen Robertson, Jeff McLaughlin

"The Clarabelle Mill rock tailings have the potential to generate sulphuric acid through chemical and biological oxidation of sulphide minerals. Current rock tailings assay between 0.80 -1.40 %S, with sulphur occurring principally as coarse pyrrhotite. Acid generation within the tailings area can be substantially reduced by segregating pyrrhotite rich tailings in a submerged storage area and by depositing only low sulphur rock tailings in exposed areas. Laboratory tests confirmed that low sulphur tailings could be produced by flotation at reduced pH with a small xanthate addition. A plant test was conducted to evaluate the production of low sulphur tailings in conjunction with INCO's continuing commitment to environmental protection and progressive decommissioning of the metallurgical site.During the plant evaluation, approximately 5% of the mill rock tailings were reprocessed in a line of 100 tt3 Denver flotation cells. Tailing grades below 0.40% S were easily achieved through operation at pH 6 -7, with xanthate addition (dosages up to 0.02 lb/ton) and 10 -15 minutes of nominal retention time. Froth depths between 1 -3 inches combined with relatively liberal amounts of frother were required to pull the lightly mineralized froth into the concentrate which averaged 11% sulphur and less than 5% mass recovery. In addition, three field lysimeters were each filled with two hundred.ton bulk samples of low sulphur tails (0.35% S), standard rock tailings (0.98% S), and mill total tailings (2.30% S) for long term monitoring. The implications for full scale plant design, tailings area decommissioning, the possibility of increased nickel recovery and preliminary field lysimeter data are discussed."

Jan 1, 1994

By K. Cybulski

Coal dust explosions still remain the main hazard in the coal mining sector, notwithstanding their relatively wide recognition compared to other hazards and the development of effective methods of prevention. Coal dust explosions are still the cause of numerous catastrophes, often leading to fatalities. Fortunately, they rarely occur, and it is for this reason that their hazardous impact is often underestimated. This problem in Poland is being exclusively solved by the Central Mining Institute, Experimental Mine Barbara. Here, basic research on the phenomenon of coal dust explosions and prevention methods is carried out, as well as investigations into the causes and circumstances of past accidents. After 15 years of no coal dust explosion accidents in Poland (1987?2002), a few coal dust explosions have recently occurred, with tragic consequences. These events have taken place not only in hard coal mines, where the presence of dangerous coal dust is the result of common production cycle, and safety measures against coal dust explosions are subject to specific regulations, but also in coal-fired power plants. This is of special concern because prior to 1987, such accidents had been been reported only for coal mines and not for coal-fired power plants. In recent years, two dust explosions occurred in Polish power facilities: the Dolna Odra and Turow power plants. In both cases, coal dust explosions occurred in the fuel supply system, but biomass dust was also involved. The explosions caused significant damage to the systems and buildings. This paper gives description and schematics of the regions of catastrophic coal dust explosions that have occurred in recent years in Poland, as well as the results of post-accident investigations, presenting the coal dust explosion hazard at the accident scene The results specify in detail the state of safety measures against coal dust explosions in light of the relevant regulations in force, including amount of deposited coal dust, content of incombustible matter in coal dust, free moisture content in coal dust, state of coal dust explosion safety zones, and state of explosion barriers. The conclusions from the site inspection and post-accident investigations presented enable us to determine locations of explosion initiation, probable ignition sources, range of explosion flames, and explosion barrier performance. A complete elimination of coal dust explosion hazard at the site of dust deposition is practically impossible to achieve. Similarly, a total elimination of ignition source, which may be related to the occurrence of other natural hazards, equipment malfunction or human errors, is impossible. The examples of tragic events that took place in Polish coal mines and coal-fired power plants highlight shortcomings and mistakes made in terms of assessment and prevention measures taken against the coal dust explosion hazard.

Aug 1, 2013

By K. Scholey, S. Marcuson

As high grade nickel sulphide ores are being depleted and with the continuing challenges experienced in economically processing nickel laterite ores, it is important to investigate technologies that can extract nickel from low grade ultramafic ores which are present in large quantities worldwide. In the Thompson Nickel Belt, there are some hundred million tonnes of mineralization that are potentially amenable to surface mining. Since the original discovery of the Thompson orebody, recovery of nickel from these ultramafic deposits has been an elusive goal. Research and development projects as well as commercial processing have been attempted. In the 2000's as other resources became scarcer, a major drilling, mine evaluation and research project was initiated at Vale. In 2007, Vale Base Metals Technology Development invited Cytec and potential academic partners to participate in an industry-university research consortium with the goal of developing new technologies and methods of processing the ultramafic deposits. Three university professors, J. Finch of McGill, P. Somasundaran of Columbia and R. Pelton of McMaster accepted, each group attacking the problem with a different approach. This paper describes the management of the research consortium and the significance of the results from Vale's perspective. The next four papers in this session will summarize the project and results from the partners' point of view. Vale is pleased to share the experience of the collaborative research and development with the mining industry.

Jan 1, 2011

By N. N. Rulyov

"Starting from fundamental principles of colloid-hydrodynamic theory of disperse systems we have shown that application of strongly non-uniform hydrodynamic fields allows to achieve not only faster rates of flocculation of suspension, but also supports significant improvements in the quality of clarified water and separation characteristics of solid phase. Specifically, it has been experimentally proven that the new treatment method based on these principles (then termed as ""ultra-flocculation"") allows:•,Increase the output of thickeners and pressure filters by 1,5-1,7 times;•,Decrease solids fall through into the filtrate in the process of vacuum filtration by 2¬3,5 times;•,Improve the rate of purification of water phase in the upright thickener by 1,5-1,9 times;•,Decrease flocculant consumption by 1,5-3 times;•,Increase the effective operational life time of cloth filters by 3-4 times;•,Ensure sustainable operation of separation equipment, i.e. decrease the sensitivity of process to variation in suspension concentration, as well as to variations of suspension composition and dispersion characteristics;•,Apply flocculant solutions of concentration 2-3 times higher, thus increasing the capacity of equipment used for solutions preparation."

Jan 1, 2004

By Roméo Roussin

"The yearly production from the Asbestos Hill pit is 1,550,000 tons of asbestos ore, with a yield varying between 18 and 20 % . The orebody was exposed at the top of a hill, and initial production started without having to remove any overburden. The projected ratio of barren rock to ore, based on the present orebody, was 2 to 1. However, as it was necessary to push back the upper benches, this ratio has changed to 3 to 1. The final pit will be 2,300 feet long by 1,000 feet at the longest and widest points. The final depth will be 680 ft. A pit slope stability study was carried out and an average wall angle of 60-70 degrees must be maintained. Preshearing of final pit limits will produce good wall stability. Permanent access ramps will be 60 ft wide, with an 8 % maximum grade. Geological conditions and the low rock temperature are the major causes of the operation's drilling and blasting problems."

Jan 1, 1976

By C. D. M. Chisholm

IN discussing stope filling, or backfilling, at the Sullivan mine, at Kimberley, B.C., a brief description of the problem will first be presented. The Sullivan orebody is a replacement in quartzite, with the ore con-forming, for the most part, with the bedding. The dip of the vein, apart from local irregularities, averages about 15 degrees near the outcrop in the southwest section of the mine, and steepens to almost 40 degrees at the northeast end of the mine. The thickness varies from a few feet to over 200 feet at the widest sections. The mineable length along the strike has averaged about 4,000 feet between the 4,600 and 3,900 levels-the section under discussion in this paper. To date, 28,000,000 tons of ore have been mined by the room-and-pillar method. Prior to 1930, all ground opened up had been supported by ore pillars, left during mining operations. From that time, the recovery of the ore from these pillars has been given serious consideration. Backfilling, as being carried on today, is the result of this study and is being done for two reasons: (1) to allow extraction of the ore pillars, and (2) to minimize subsidence of the hanging-wall rock, except where forced caving is found desirable. PRELIMINARY DEVELOPMENTS LEADING TO BACKFILLING When the Sullivan orebody was first opened up, early in the century, there appeared to be low-grade sections of the vein sufficient in extent to serve as permanent support for the roof. However, as mining extended into sections of the vein that showed continuous ore over greater areas, wooden cribs, filled with waste and low-grade ore, were erected. In some stopes, these cribs were as large as 40 ft. by 100 ft. in plan and from 50 ft. to 60 ft. in height, but it was soon realized that this method of support was inadequate. As mining progressed, it was found necessary to leave ore pillars, which eventually became the sole system of support. At first, these pillars were left at irregular intervals, but later they were laid out at definite locations on the mine plans, and these locations were adhered to as closely as mining would permit.

Jan 1, 1941

By D. M. Aloi

In today's evolving and globalized world, mining companies are being pressured to move beyond compliance towards long-term sustainability and sustainable development. Companies are expected to "engage" with communities and measure the success of these engagements without a clear understanding of "how" to do this. This move, away from "Corporate" Social Responsibility (CSR) and compliance, develops more of a focus on "Community" Social Responsibility and sustainability. This shift in focus leads to the development of world-class projects that provide sustainable development for people, reduces the incidence of costly delays, and promotes good global citizenship for corporations. The process of "engaging" communities in mining project design and development leads to a stronger license to operate and sustainable development. To create this mutually beneficial relationship between communities and companies, communities must be "engaged" in the mining process as early as possible, preferably during the exploration or the concept phases. How to create this "engagement" remains elusive. How to measure the progress of this engagement is also problematic. The quantitative and qualitative metrics needed to measure both positive and negative impacts of the mining and community relationship will be discussed.

Jan 1, 2007

By Dirige. A. P. E.

A study was conducted for an operating mine to determine the appropriateness of its tailings material to be used for the preparation of a low modulus, high density backfill. The research was initiated due to issues arising from increased observations of compressive failure of backfill placed in stopes and inconsistent backfill behaviour (i.e. increased backfill brittleness and modulus). Backfill materials investigated were classified tailings and de-slimed tailings. Characterization of the physical properties of the classified and de-slimed tailings materials was conducted to assess the effect that these material properties would have on the strength and deformation behaviour of high density backfill products made using them. Such behaviour was investigated to determine whether differences in tailings physical properties would influence the strength and modulus character of the backfill materials. Uniaxial (UCS) and consolidated-undrained triaxial compression strength tests were conducted to determine strength performance and deformation behaviour of backfill. This paper presents the results of the backfill material characterization study and how different particle size distributions affected the strength performance and deformation behaviour of the different backfill mixes. It also demonstrates how stress-strain curves generated from material strength tests were used to evaluate variation in high density backfill mix response when such materials were subjected to unconfined and confined (triaxial) compression loading.

Aug 1, 2013

By K. Becerra, D. G. Almond, T. D. Maru

"Nkomati Nickel Mine in South Africa processes one of the world’s hardest ores in a 375k TPM autogenous grinding circuit. The plant employs an unconventional processing circuit, comprising a primary autogenous mill (AG or FAG) and pebble crushing circuit followed by a secondary hybrid pebble/ball mill and classification cyclone cluster.Advanced Process Control (APC) or Expert Control is now generally accepted as an advantage in most modern high capacity concentrator grinding circuits. This paper reviews the installation of model predictive control at Nkomati and examines the results and benefits of installation in an autogenous mill during plant ramp-up. The paper also demonstrates how predefining process control objectives together with good plant and supplier cooperation can achieve a robust and reliable APC implementation on a very short site program.The results conclusively demonstrate operational and economic benefits during circuit operation with the advanced process control system ON. Production performance and circuit stability were significantly better than during manual control."

Jan 1, 2012

By E. Lehtila, J. J. Talja, R. Jahila

Kopar Oy is acknowledged for engineering and manufacturing of robust systems for bulk material handling, especially at power plants and non-ferrous smelters. We have over thirty years of experience with systems specifically designed for hot and abrasive conditions, aiming at low cost of ownership, low operational expenses and high availability. Although Kopar has numerous applications in mechanical conveying, there is an increasing number of pneumatic conveying applications at copper smelters. They relate to conveying of concentrate, and primary and secondary flue dusts. Challenges of pneumatic conveying for concentrate are mechanical and do relate to broad particle size distribution and high abrasivity of the concentrate and the silica. Therefore, special attention shall be paid to system design and ceramically lined bends in the pipeline. Challenges of pneumatic conveying of primary flue dust relate predominantly to material stickiness and poor flowability which are mainly due to fine particle size and formation of sulphates and furthermore, crystalline water. Additional challenges of secondary dust, the white converter dust, are primarily due to the extremely fine 0.1–1.5 µm particle size and problems which come with this. Effect of material characteristics like size distribution, morphology and chemical composition in pneumatic conveying are discussed in detail. INTRODUCTION Fine materials like concentrate, feed mix, flue dusts (from waste heat boiler and electrostatic precipitator) and secondary dusts need to be conveyed at smelters. Both horizontal and vertical conveying and combination of those are used. For the purpose, both mechanical and pneumatic conveying are applied. Most widely used equipment are drag chain conveyors and various combination of pneumatic systems, e.g. air lift, dense-phase and dilute phase pneumatic conveyors. Kopar has 30 years’ experience with multiple material handling systems. Furthermore, acquired companies like Elmomet Oy and SITE Oy (both currently fully merged and integrated into Kopar Oy) have even longer history, especially in pneumatic conveying. It is commonly known that the finer the dust the more difficult it is to be conveyed pneumatically. Sulfates with crystal water makes it all even more difficult, if not ineligible. Challenges related to pneumatic conveying of various fine materials is discussed in detail in the paper.

Jan 1, 2019

By S. D. F. Rocha1, L. Katsarou, G. P. Demopoulos

"Crystalline scorodite (FeAsO4·2H2O) has been pointed out as the most stable compound to immobilize arsenic for disposal due to its good stability performance according to EPA’s TCLP test. However, in anaerobic conditions, arsenic releasing is increased to undesired levels due to scorodite reductive break down, in eh <100 mV at 5.5< pH <7 which causes contamination of groundwater. In this work, the concept of encapsulation by controlled deposition of mineral coatings immune to pH or redox potential variations is presented. Aluminum and calcium phosphates were evaluated as coatings and the release of arsenic from scorodite previously coated with phosphates was substantially decreased when compared to the VALUES (obtained from crude scorodite, both in oxic and anoxic conditions. INTRODUCTIONThe widely acknowledged hazardous properties of arsenic as a soil and natural water contaminant and its adverse health effects when present in drinking water have led to very strict environmental regulations (Mandal & Suzuki, 2002) aiming at the drastic reduction of the presence of arsenic in the effluents of the mining and metallurgical industries.In Canada, the Metal Mining Effluent Regulations (Government of Canada, 2002) dictate that the maximum monthly mean concentration in tailings for arsenic must be lower than 0.5 mg/L. At the same time the new Environmental Protection Agency’s (EPA) standard for drinking water foresees concentrations of arsenic less than 0.01 mg/L, which means that the leachability limit for the industrial waste is set at 1 mg/L arsenic (EPA, 1994; Le Berre et. al, 2007). One of the preoccupations of the mining and metallurgical industries is directed to the elimination of arsenic presence in all its effluents, especially since arsenic is commonly found in many ores mainly in the form of oxides and sulphides. After processing of arsenic-containing ores and concentrates, arsenic can be present either in solid residues and tailings, liquid effluents or in flue dusts. Several of these forms of arsenic waste materials are soluble and therefore may cause the contamination of ground water, if disposed of without further treatment."

Jan 1, 2012

By O'Halloran. Gerard F.

"ECSTALL MINING has installed in their plants the most modern equipment in the mining industry. At the minesite, digital blocked frequency controls are used to monitor all crushers, conveyors, ventilation equipment and pumps from underground. Distant pumping stations are monitored and controlled by radio. Modern friction skip and cage hoisting systems have been installed with static power supply designed for automatic operation. Rotary-type compressors of recent design are in service in place of the conventional reciprocating-type units. At the concentrator, the 800- and 1500-hp synchronous motors driving the grinding mills have static field excitation and pneumatic clutches, still meeting modern-day concepts, having been• installed in 1966. The maintenance work load has increased annually for the past eight years. The modern plant, with all the present-day sophistication, must have a welltrained and well-organized force of skilled workers, and a maintenance system which will supply realistic facts and guidelines. This presentation will review the relative location of plants, utilities, maintenance and services, plant maintenance control and mechanical control. It is the hope that enough information will be presented to weigh the size of the job and how the resources are utilized for controlled maintenance."

Jan 1, 1974

By J. W. Choung, T. Fu, Z. A. Zhou

An on-line visualization technique and methodology was developed to investigate the role of fine sphalerite (< 10 um) aggregation in flotation. The images of particle aggregates under different operating conditions were recorded and analyzed. The effect of impeller design on particle aggregation was demonstrated. This difference was not mainly due to the energy input into the system, but due to the resultant hydrodynamic conditions created by the impeller and their effect on particle interactions. The recorded image showed that adding fine silica (- 5 um) did not interfere with fine sphalerite aggregation, thereby showing no effect on the sphalerite recovery. Effect of the enlarged aggregate size on increasing flotation recovery was confirmed. Although Malvern Mastersizer produced consistently lower estimates of aggregate size than those by the image analysis, both methods responded to the changes in operating conditions in the similar trend. It was shown from this study that on-line visualization technique is a powerful tool for studying fine particle aggregation and morphology in the context of diagnosis for the flotation separation.

Jan 1, 2004

By M. Mbonimpa

Field experimental cells were constructed in 2007 to assess the performance of different cover scenarios for the reclamation of the Parc 1 tailings disposal facility at the Westwood-Doyon Mine site (Abitibi, Quebec). Three configurations of cover with capillary barrier effects (CCBEs) with different thicknesses and material types for the moisture retention layer (MRL) were studied. MRL with 80 cm till, 40 cm till, and 40 cm clayey silt were used for cell nos. 2, 3, and 5, respectively. The capillary barrier layer (CBL) and drainage and protection layer (DPL) of the CCBE consisted of 30 cm gravel. A reference cell without cover was also constructed to compare the geochemical performance of the CCBEs. Due to an unexpected flooding in the leachate exit area of the cells in spring 2008, the cell instrumentation for hydrogeotechnical monitoring was postponed to spring 2009. Changes with time in volumetric water content, suction, soil oxygen concentration, and temperature were measured at different depths. This paper presents and discusses preliminary results obtained from spring 2009 to autumn 2010. In all cases, the degree of saturation Sr is lower in the CBL than in the MRL, indicating the presence of capillary barrier effects at the interface of these layers. Cell nos. 2 and 5 showed hydrogeotechnical behavior typical of an effective CCBE, with Sr maintained above 85% in the MRL and lower than 30?50% in the DPL and CBL. Based on the obtained results, and as expected, MRL thickness and the type of construction material used appear to affect the hydrogeotechnical behavior of the CCBE. Oxygen concentration profiles through the CCBEs were used to estimate the oxygen flux, and results indicate that cell nos. 2 and 3 performed better than cell no. 3. CCBE performance is currently being investigated using the geochemical monitoring data.

Aug 1, 2013

By Karl J. C. Harries

"3.1. INTRODUCTIONThis chapter discusses briefly the common law concepts of fiduciary relationship, constructive trust, and breach of confidence. Following a discussion of confidentiality agreements, the last section of the chapter compares and comments on two common law cases, the LAC Case and the Metalore Case. Civil law readers should not ignore this chapter or § 3.5. the comparison as, to a large extent, the concepts and comments are universal, even though the procedures for applying them may vary.1It should be appreciated that, regardless of the legal system, if the Court sees that a wrong has been done, it will attempt to right that wrong, either by awarding monetary damages against the wrong-doer to compensate the injured party or by attempting to make the injured party whole again by such means as negating an agreement (as in the Metalore Case) or returning property to a wronged party (as in the LAC Case). The methodology for accomplishing either of these results will vary with the jurisdiction, and the two are not mutually exclusive.These two Ontario cases have been chosen, not because they are the only ones available – they certainly are not – but because both are relatively well known within the minerals industry and they deal with problems that may face any explorationist (although it is to be hoped that the facts of the Metalore Case do not represent “normal” behaviour). Each judgment offers useful guidelines, as well as insight into a judge’s approach to problems, the type of information he expects to receive, how his mind works, and, particularly in the Court of Appeal judgment in the Metalore Case, how he might reason through and “justify” his decisions.3.2. SOME LEGAL CONCEPTS In order to appreciate some of the matters discussed in this chapter, it is necessary to have some idea of the common law considerations of fiduciary relationships, constructive trust, and breach of confidence."

Jan 1, 2003

By Maureen McGuiness

"The pastefill circuit at the Bell Allard Mine in Matagami, Quebec started up in August 1999. The surface pastefill plant produces a cemented paste which is sent underground by gravity through a vertical pipeline in the mine ventilation shaft. Difficulties with paste flow during the start-up highlighted the importance of understanding paste rheology and the effect of operating procedures on line wear. By June 2000, the original circuit had been modified to include a paste pump to transport the paste to the shaft.The steps taken during the paste plant commissioning are discussed. The final flow sheet is presented, focussing on the use of instrumentation to ensure full column flow and proper distribution underground. Resistance modelling and accelerated curing of samples are examined as possible ways of predicting paste resistance to ensure compliance with the mine’s paste specifications.INTRODUCTIONCommissioning a new plant can be difficult and time consuming. The start-up of Noranda’s Bell Allard paste backfill plant was no exception. Since the first day it went into operation, the paste circuit could not meet the tonnage and paste quality requirements of the mine because the paste would not flow by gravity into the vertical pipeline in the mine’s ventilation shaft.Diagnosis of the pastefill problems proved difficult. It was only when the rheology of the Bell Allard paste was understood that the flow problems were solved. To ensure that the paste placed in the stopes meets mine requirements, two methods of paste resistance prediction are being developed."

Jan 1, 2002