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By J. D. Stewart

One of the first important questions that should be settled on the opening of a mine or the development of a new deep is the system of haulage to be used, since the layout of the haulage-ways at the pit bottom, or, in case of a slope mine, the arrangement of the surface works, depends largely upon the type selected. Should it later become desirable to install a system of haulage of a type other than that for which the mine roadways were originally laid out, considerable difficulty would likely be encountered in its installation and with the result that it would in all probability be most unsatisfactory and expensive in its operations. It therefore becomes very necessary that full consideration be given the haulage problem at an early date in order that the type best suited to the mine conditions and the required outputs can be intelligently planned for. It is sometimes found, however, that no matter how well the mining engineer explores the seam to be developed, or how accurately he anticipates its eccentricities, there will still remain some unrevealed or unsuspected conditions, or shall we say obstacles, placed by Nature to prevent the too easy winning of her treasures and incidentally to frustrate or modify the application of the plan so painstakingly laid down on paper, and to adversely affect the cost estimate.

Jan 1, 1928

By G. Szilvay, P. Kinnunen, J. Salminen, V. Miettinen, O. Salmi, J. Mäkinen

This paper demonstrates experimental studies on bioprocessing of different waste streams. In Part I of this paper three tailings from mining industry were bioleached with mixed acidophilic culture in order to solubilize valuable metals, like copper, nickel, zinc and manganese to leaching liquor. Bioleaching resulted in > 70 %, > 85 %, 100 % and > 70 % leaching yields for Cu, Ni, Zn and Mn, respectively. However, contaminants like arsenic and chromium were not leached efficiently and they will cause challenges in residual solids and sometimes also in metal recovery from leaching liquor. Bioleaching resulted in 99 % leaching yield for copper. Part II demonstrates mine water treatment and also gold recovery from process liquids with biosorption method. The novelty of biosorption was finding that certain fungal species were able to be cultivated to self-immobilized systems, which are easier to operate than traditional suspended biomass methods. Biosorption resulted in more than 90 % removal for all contaminants, but was also seen to be gold selective.

Jan 1, 2014

By D. A. Beattie

Talc is a commonly encountered gangue mineral in metal sulfide flotation. Talc is naturally hydrophobic, resulting in high recoveries if polymeric depressants are not used to specifically reject this MgO containing mineral. We have studied the adsorption of a selection of polymers onto talc using a variety of techniques. Adsorption isotherms have been determined using ex situ depletion techniques and in situ ATR-FTIR spectroscopy has been used to determine adsorption kinetics. Adsorbed layer thicknesses have been determined for the polymers on cleaved talc surfaces using the AFM. The effect of the adsorbed polymer layer on the properties of the talc surface has been quantified through contact angle measurements and single mineral flotation tests. Distinct correlations are observed between the adsorbed layer properties and the flotation performance of the polymers. These observations are discussed with reference to the bubble-particle attachment process and the molecular structure of the polymers.

Jan 1, 2006

By K. Chotruangprasert

This paper explores Global Reporting Initiative (GRI) reporting practices within the mining industry. Specifically, this paper investigates how and why a mining company makes voluntary reporting decisions to include the GRI indicators that may be considered ?negative? to the company?s reputation. Due to the voluntary nature of the GRI Guidelines, a GRI adopter is not legally obligated to report every GRI indicator. Not surprisingly, empirical studies that evaluated the extent to which companies? sustainability reports meet the GRI requirements (Guenther, Hoppe, & Poser, 2006; Morhardt, Baird, & Freeman, 2002; Samy, Odemilin, & Bampton, 2010; Skouloudis, Evangelinos, & Kourmousis, 2009) have found that reporting practices of the companies under their studies are well below the standards reflected in the GRI Guidelines. An influential study by Clarkson et al (2008) uses economic-based and socio-political theories to explain variation in companies? environmental disclosure. They have found that, as predicted by economic-based theory, superior environmental performers disclosed more ?hard? (i.e. verifiable) environmental information. Inferior environmental performers are found to disclose more ?soft? (i.e., not easily verifiable) claims, which is consistent with socio-political theories (Clarkson, Li, Richardson, & Vasvari, 2008). However, this study and the existing literature do not adequately explain why a company may act in a way that cannot be explained by economic-based and socio-political theories, for example, why it would report some negative soft data that it is not required to report. This paper intends to address this literature gap. GRI reporting by a Canadian mining company, which I would like to call ?Company C?, is used as a case study for this paper. Company C was selected for this research because in addition to ?positive? information, its GRI-based sustainability report also includes both hard and soft ?negative? information such as grievances. Research methods include interviewing Company C?s employees who are involved in preparing GRI reports and reviewing documents prepared both by the company and by external parties. I find that integrative social contracts theory (ISCT) offers a valuable explanation to Company C?s reporting practices. From the ISCT perspective, Company C?s management appears to feel that the company is obligated under social contracts to be transparent. Therefore, Company C disclosed both positive and negative social and environmental information to the public because the management appeared to think that it is the right thing to do. At the same time, being transparent about the bad news gave the company an opportunity to conclude that it had done something to avoid future occurrence of the negative incidents. Therefore, I propose that, in addition to the economic and socio-political theories that are more often used in literature, insights from ISCT are instrumental in improving our understanding of the corporate non-financial reporting practices phenomenon.

Aug 1, 2013

By W. Holyk

"Although lead, zinc, copper, and iron sulphides have been known for many years in the Bathurst region, the existence of large massive deposits was not known until the discovery of the Brunswick orebody in 1952. This was followed by the discoveries of the Anacon orebody in 1953 and the American Metals orebodies in 1954. There is no question as to the great importance of these large massive sulphide deposits, and no doubt that other sulphide deposits are to be found. The problem, of course, is where and how to find them.The discovery of the Brunswick and Anacon orebodies is attributed to geophysical work. The original discovery of the American Metals deposit is generally attributed to a regional airborne electromagnetic survey.It is generally stated that the Bathurst area is a geophysical camp, and this is essentially true, but in this highly competitive search for orebodies it is obviously impossible for an individual company to cover the entire area by a comprehensive geophysical survey. Some means other than geophysics must be used to narrow the target. The quickest, cheapest, and simplest method is geological investigations.It has been stated that nothing can be accomplished by geology in the Bathurst region, since the camp is largely covered with overburden. This is true only insofar as detailed work on certain properties is concerned. It is not true of the larger regional picture. Outcrops are scarce, but angular float is abundant, and precedent shows that angular float has moved but a short distance from its source.GeologyAeromagnetic maps published by the Department of Mines and Technical Surveys are the best guides to the geology and structure of the area. These maps supply factual information concerning the underlying rocks. When coupled with field investigations, they are very useful in the interpretation of regional geology and the selection of favourable areas. The discussion of the geology is accordingly centred upon the aeromagnetic maps. The following is essentially a working theory, based on geological facts as best reconciled with all other available information,"

Jan 1, 1949

By D. B. Johnson

Acidic, metal-rich waters generated at working metal mines and abandoned mine sites are generally considered to be major pollutants of the environment. However, the metals they contain often have significant value of their own, or as sources of useful mineral products. We have developed novel bioreactor systems that facilitate the selective recovery of various transition metals (e.g. copper, zinc and iron) as defined minerals that can be recovered and recycled. The bioreactors use novel species of acidophilic bacteria. Ferrous iron is oxidised by Ferrovum myxofaciens, a specialist bacterium that forms large amounts of exopolymers and grows as filamentous streamers in flowing mine waters, and the ferric iron generated is precipitated as the mineral schwertmannite, a small proportion of which is used to remove any arsenic present in mine water. Copper and zinc are precipitated as sulphides using H2S generated by consortia of acidophilic and acid-tolerant sulphate-reducing bacteria in a continuous flow, on-line low pH bioreactor. Transition metal sulfides can be segregated by precipitating them, either on-line or off-line, at different pH values. The modular units that have been developed can be configured to treat mine waters of different chemistries. A hypothetical acidic (pH 2.5) mine water stream containing 500 mg/L iron, 100 mg/L of copper and zinc, 50 mg/L of aluminum and manganese, 2 mg/L of arsenate, and discharged at a rate of 10 L/s, is used as an example of the potential application of the mineral-generating bioreactors. The environmental benefits and economic implications of considering mine waters as resources rather than wastes are discussed.

Aug 1, 2013

By Patty Simpson, Sarah Benson

In an effort to improve consistency across the nuclear industry, over the past 10 years the Canadian Standards Association has developed a series of standards related to environmental management at Class 1 nuclear facilities and uranium mines and mills. Canadian uranium mines have been required by the Canadian Nuclear Safety Commission to align their existing monitoring programs with these standards. Orano’s McClean Lake Operation’s monitoring program, which was originally presented in the Environmental Impact Statement in 1991, has evolved through regulatory change, new scientific understanding, additional projects, and experience into a comprehensive set of monitoring requirements for effluent, groundwater, air emissions, and the receiving environment. The exercise of aligning the existing practices with the standards provided an opportunity to review and rationalize the entire program. To document the process the original “Environmental Monitoring Program Design Document” was restructured and developed as both a repository for historical information and monitoring rationalization, and also to be a living document describing on-going studies and supplementary work that are outside of the regular environmental monitoring program and may justify future changes to the program.

Jan 1, 2020

By D. H. Schwarz

The performance of proton exchange membrane (PEM) fuel cells depends on catalyst layer composition and structure. Experimental observations reveal that state-of-the-art catalyst layers consist of microporous agglomerates of carbon-supported catalyst sites bound together by polymer electrolyte. In between the agglomerates are macropores which provide pathways for the transport of gaseous reactants. In this work, three-dimensional, multicomponent and multiphase transport computations are performed using a computational fluid dynamics (CFD) code (FLUENTTM) with a new PEM fuel cell module, which has been further improved by taking into account the detailed composition and structure of the catalyst layers using a multiple thin-film agglomerate model. In this model, it is assumed that thin films of polymer electrolyte and liquid water surround the catalyst sites. The results of CFD computations show that transport limitations associated with the thin film of polymer electrolyte and the presence of liquid water in the catalyst and gas diffusion layers have substantial negative effects on PEM fuel cell performance. Also, the results of computations with variable distributions for a given precious metal loading show that, in general, uniform catalyst loading provides the best fuel cell performance.

Jan 1, 2005

By D. B. Dreisinger, A. A. Gunaratnam

A pressure oxidation (POX)-hot cure (HC)-lime boil (LB) process is used in industry to recover silver from refractory gold sulfide ores containing minerals such as pyrite and arsenopyrite. Pressure oxidation is used to oxidize minerals and liberate occluded gold particles. As such, iron goes into solution and under acidic and high temperature conditions often precipitates as basic iron sulfate (BFS). BFS consumes excess lime during neutralization prior to cyanidation. Therefore, a hot cure stage is required to re-dissolve BFS back into solution. BFS re-dissolution consumes acid and produces ferric sulfate. In the presence of silver, these conditions favor the slow formation of silver jarosite. Silver jarosite is refractory to cyanidation, and must be broken down prior to cyanidation. This is done in the lime boil to produce a cyanide-soluble silver hydroxide. A study was conducted to investigate parameters that affect the precipitates that form in each stage of the POX-HC-LB process.

Jan 1, 2017

By W. G. Jewitt

Introduction The use of the aeroplane in prospecting is already familiar to everyone connected with the mining industry. Apart from transportation companies, three organizations, the N. A. M. E., the Dominion Explorers, and the Exploration Department of the Consolidated Mining and Smelting Company, have made the aeroplane an everyday feature in every mining district in Canada. Its use has been demonstrated successfully in the mountains of British Columbia, but perhaps its greatest field lies in the Canadian Shield, where the numerous lakes and rivers afford an almost continuous series of landing places for aeroplanes, on floats in the summer and on skis in the winter. To the man who has travelled by canoe, toiling over fly-infested portages or held for days at a time, wind-bound, on the big lakes, the ease, speed, and cheapness of aeroplane travel have marked the beginning of a new era, in which ground previously covered with difficulty in a month or more is travelled with ease in a few hours. Development of an air service in the Consolidated Mining and Smelting Company has proceeded on different lines from those of other organizations, and this paper is concerned with that development.

Jan 1, 1931

By J. Aydt, W. McCombe, H. McLaughlin, L. Nightingale-Mercer

The McClean Lake mill is located approximately 850 kilometers north of Saskatoon, Saskatchewan, Canada and is operated by Orano Canada Inc. (Orano). The mill was designed to process high grade uranium ores, and in 2014 completed a multiyear expansion to increase its production capacity to 24 Mlbs U3O8 per annum. This expansion included significant changes to the mill’s secondary leach circuit in support of safely processing high grade ore directly from the Cigar Lake mine. In particular, inter-stage pumps were introduced for slurry transfer between the secondary leach tanks, replacing the original pressure feed forward operation. The design and selection process for these pumps was strongly influenced by the uncertainty related to actual radiation dose exposure when processing undiluted high grade ore (up to 30%U), and consequently the desire to maintain minimal occupancy in the vault enclosure containing the secondary leach tanks. These constraints resulted in the decision to install positive displacement pumps above the leach tanks in a suction-lift configuration. Operating experience with this design has shown that the pump capacity is significantly de-rated due to process solution gas-entrainment and pipe scale build-up, particularly in the front end of the secondary leach circuit where reagent dosage is high. Experience processing high grade ore also provided accurate radiation dose data to demonstrate that the level of occupancy in the leaching vault enclosure could be re-evaluated to accommodate alternate pump configurations. This paper reviews the lessons learned and improvements made to safely increase the capacity and reliability of the leach inter-stage pump system.

Jan 1, 2020

By O. Alonso-Gonzalez, F. Nava-Alonso, A. Uribe-Salas, R. Pérez-Garibay, C. Jimenez-Velasco

A current problem in gold production is the presence of copper minerals which dissolve during conventional cyanidation practice. The dissolved copper causes several problems in the different stages of the process. This issue is the base for copper elimination/recovery methods such as the Sulphidization, Acidification, Recycling, and Thickening (SART) process, which is currently used in gold production plants around the world. Even though the process is well established, new challenges appear as the composition of the solution varies from ore to ore, in some circumstances affecting the performance of the SART process. This work presents a thermodynamic study and experimental tests performed to understand the role of the initial copper concentration and sulfur addition, on the efficiency of the copper removal. For a constant cyanide concentration, an increase in the initial copper concentration causes a decrease in copper removal; high sulfur/copper molar ratios favor copper removal. We demonstrated that the cuprous sulfide formed from solutions with high ionic strength, presents better sedimentation rates than solutions with less ionic strength. For solutions with low sedimentation rates, the use of some pretreatment is necessary to facilitate the sedimentation such as addition of flocculants, particle recirculation and the used ultrasonic pretreatment.

Jan 1, 2014

By Mike Smith, George Chung

"A 23 million dollar Flotation Plant has been commissioned at the Iron Ore Company of Canada in 1998. Nine OK-50 cells &re used to float silica in this 1,400 tomes per hour plant. The paper details project development, construction and operating results. This plant gives IOC the capability to produce not only high quality blast furnace pellets of varying silica, CaO and MgO levels, but also a high iron, DR grade pellet. The first activity was simply to sit down with the suppliers, Outokumpu, Wemco. GL&V and Svedala, to discuss applications and share experiences. We learnt what each supplier had to offer, what features would particularly suit this application, what options were offered, what were the materials of construction, how the equipment is maintained, which wear parts require replacement, etc., etc. We tried to learn as much about the equipment as the suppliers themselves knew. Then we tried to learn more: we contacted users and asked about any weak points, which options were worth incorporating and which items were not. We then discussed these points with the suppliers and established how potential problems might be overcome."

Jan 1, 1999

By N. Melnyk

IN the past, the Cadomin Coal Company has opened four mines, all in the same coal seam or its folds. Three of these were opened from river level by horizontal entries or rock tunnels, and the fourth, the present working mine, by vertical shafts. This paper deals largely with some operating phases of this fourth mine, with which the writer has been associated. The seam worked here is a thick, steep, bituminous seam, and the writer feels there is a paucity of published data on the mining of such seams. Possible reasons for this are that such seams do not !end themselves to intensive development or mining, there is little chance to mechanize because of the extreme pitch, and operations are fraught with many problems. In addition, the present operations in this particular seam are being carried on at a level below the former workings, introducing new problems, not en-countered on the upper level. Coal will, without question, long continue to be an important factor in the national economy, and some of the best coal is to be found in thick, steep seams. But with the exhaustion of the easily-mined coal near the outcrops, future coal will have to come more and more from lower levels. At Cadomin there is still considerable coal on the second level, below the old river-workings, and there is a possibility that, in the future, still lower levels will be worked. It is the purpose of this paper to indicate some phases of such lower-level operations and to invite discussion.

Jan 1, 1942

By D. C. Fraser

"Geophysical Engineering and Surveys Limited of the Keevil Mining Group have routinely conducted ground surveys with VLF-EM receivers for the past two years. Both Crone's Radem and Ronka's EM16 have been used.VLF-EM dip-angle data often yield complex patterns which require considerable study for a proper interpretation. A method was developed which allows field operators to transform the noncontourable dip angles into contourable data, producing conductor patterns which are immediately apparent to exploration personnel untrained in VLF-EM interpretation.VLF-EM contoured data generally peak very close to the top of a conductor, thereby allowing drill holes to be spotted accurately. However, the data generally should not be used alone to select drill targets because structures may be sufficiently conductive to yield strong anomalies. Thus, magnetic and/or vertical-loop EM correlations may be considered as necessary criteria for drilling.VLF-EM surveys can replace IP surveys in certain environments. For example, the Restigouche orebody in the Bathurst camp of New Brunswick yielded a VLF-EM anomaly as distinct as that obtained by IP, although the body did not respond to vertical-or horizontal-loop EM. However, the cupriferous breccia pipes of the Triba mine near Batchawana, Ontario yield strong IP anomalies but not VLF-EM anomalies, illustrating that disseminated ore targets should be sought with IP rather than with VLF-EM."

Jan 1, 1971

By B. Arsenault

Aluminum coatings can provide galvanic cathodic protection for several metals and alloys, In order to be a suitable protective solution on structural components, the mechanical integrity of the component must be preserved, In particular, fatigue properties are a challenge for thermal-spray protective coatings on mechanical structures, To address the issue of the fatigue integrity of 7075 aluminum alloy with an arc-sprayed protective coating, different surface preparations prior to arc spraying were considered, In the present work, a feasibility study was performed using laser ablation as a surface-preparation technique before or during arc spraying of coatings, This was collaborative effort between the LERMPS laboratory in France, the National Research Council Canada and the Royal Military College of Canada, Both fatigue and adhesive properties of aluminum coatings were evaluated in relation to substrate-surface-preparation techniques including laser ablation (Protal® process), grit blasting and shot peening. Results indicate that a combination of key conditions, including the use of nitrogen as the arc spray gas, shot peening, and proper laser energy density for ablation, provide high fatigue resistance of metallic coated 7075 alloy substrates. Specimens prepared under these conditions show a similar fatigue resistance to uncoated substrates.

Jan 1, 2005

In the leaching and recovery of gold from copper containing gold ores using cyanidation, some copper minerals also dissolve which can have a detrimental effect on the process efficiency and economics. There are also environmental concerns with current operations discharging cyanide and copper cyanide species into tailings dams, and strict regulations prohibit this for greenfield plants. Cyanide destruction however is not an economic option for new plants treating copper-gold ores. This paper evaluates a potential recovery process to overcome the copper cyanide problem. Despite gold dissolution occurring in copper cyanide solutions having no free cyanide, gold recovery from ores is lower compared to free cyanide. Thus, cyanide addition has to be optimised to maximise the gold recovery whilst endeavouring to eliminate free cyanide at the completion of leaching (CN:Cu less than 3:1). Subsequently, copper cyanide can be recovered using activated carbon. The loaded copper cyanide is easily recovered from the carbon with a cyanide soak and distilled water wash such that the eluted CN :Cu ratio is less than 4:1. The copper could be recovered efficiently by electrowinning, by decreasing the pH of the eluant to 5. The remaining cyanide solution, after electrowinning, is then neutralised to form NaCN and recycled.

Jan 1, 2005

By O. Lashkari

Swirled Enthalpy Equilibration Device (SEED) is a new patented Slurry-on-Demand, SoD, processing route. The semi-solid slug preparation is carried out by off-center swirling of aluminum melt in a metallic mould. As part of the current research program on the semi¬solid processing of aluminum alloys, the morphological evolution of 356 aluminum foundry alloy microstructure is reported here. Semi-solid slugs were prepared using two different pouring temperatures of 645°C and 695°C respectively. Morphological evolution of the semi-solid microstructure was characterized using image analysis through measuring of primary a-Al particle size, number density, aspect ratio and sphericity. The possible relationships between microstructural features and process parameters were also investigated. The current report covers the effect of pouring temperature on the morphology of primary a-Al dendrites and attempts are made to explain the differences between the predicted percentage primary a-Al phase and those of the actual values in the as-cast slugs.

Jan 1, 2004

By Kristie D. Tarr

Ideally, in situ monitoring would supply the input data for numerical modeling of backfill material property requirements. However, clue to production requirements and costs of conducting field tests, input data are often based on small-scale laboratory tests. The size of test samples is known to play an important role in the laboratory assessment of the behaviour of geotechnical materials, including backfill. There are observed differences between the mechanical properties of laboratory-scale samples and those of in situ materials, and these are generally attributed to the differences in scale. Various scaling factors have been proposed for converting laboratory observations to anticipated in situ conditions for soil and rock materials. With regard to mine backfill, very limited studies exist which have involved the effects of sample size on material properties. The literature indicates that reported backfill strength data are based on a variety of test sample sizes and in some cases, specimen geometries. Carefully determined laboratory scale effects could play an important role in estimating the potential backfill behaviour in the field, especially when developing new backfill systems. Laboratory studies were conducted with sample diameters ranging from 50 to 300 mm. Scale factors relating specimen size to strength were developed wherever possible, and are presented in this paper

May 1, 2008

By D. Larouche, M. Mardan

Hot tearing is a complex defect in aluminium castings which is produced during solidification when a certain amount of liquid phase remains and weakens tensile resistance of the alloy. In direct chill casting of aluminium alloys, hot tears initiate at the surface of sheet ingots just after the primary cooling zone, where the microstructure is particularly vulnerable. In order to study the hot tearing susceptibility of these alloys, and the effect of grain refiners on their thermo-mechanical behavior , tensile tests were carried out in the semi-solid state ( ~95% solid) and at low strain rates using an apparatus called DCSS, for Direct Chill Surface Simulator. This apparatus, originally developed at Alcan Arvida R&D Centre (ARDC), is an instrumented rig test reproducing the conditions prevailing during the primary cooling stage of the DC casting process. The mechanical behavior of solidifying shells and the hot tear formation under applied tensile loads were measured and the occurrence of hot tearing was observed. Temperature in different locations of the casting, applied load and surface strain were monitored during the tensile tests conducted on aluminum alloys AA5182, AA6111 and AA3104. The microstructure of the tested samples was examined using the optical microscope to evaluate their columnar or equiaxed aspect and their effect on the mechanical response of the alloy. A special emphasis has been given to the evaluation of fractions solid existing in the castings at the start of the tensile tests, taking into account the local temperature, thermal gradient and cooling rates experienced. It was found that excessive grain refiner additions decreased the strength of solidifying shells because of the increased level of porosity induced by easier nucleation of new phases (gas included). It was also observed that cooling rates increased with the level of grain refiner, a phenomenon that was associated to the higher number of contact points obtained with small equiaxed grains. Finally, the concept of a stress based criterion for hot tearing was reinforced by the strengths obtained on not grain refined AA5182 and AA6111 showing similar fraction solid near the surface, but significantly different grain sizes.

Jan 1, 2006