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By Barbara Kirby

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

May 1, 2010

By Tao Cheng

Previous research and applications in construction resource optimization have focused on tracking the location of material and equipment. There is a lack of studies on automated monitoring of the interaction between workers and equipment for safety purposes. This paper presents a new approach for measuring the safety performance of construction personnel particularly when they work in very close proximity to moving equipment as well as static hazards such as chemical and flammable substances. A method of generating hazardous zones according to the geometric and kinematic characteristics of the considered hazard is introduced. The spatio-temporal relationships between the hazardous zones and workers? positioning data collected by real-time location sensing technology are automatically analyzed. This approach has been validated in a controlled test bed environment that simulates a construction site. Results indicate that worker?s safety performance of selected activities can be automatically and reliably measured using the developed approach. Furthermore, a heat map is generated for visualizing proximity related issues in the test bed using the computed results.

Aug 1, 2013

By André Bérubé

Since the disappearance of Les Forges du Saint-Maurice at the end of the last century, many historians have taken an interest in the lengthy past of this enterprise. They considered the political, socio-economic, administrative and anecdotal aspects of the industry, but barely dealt with the elements of technology. The purpose of this article is to try to fill this gap (1). Les Forges du Saint-Maurice was an integrated industrial concern, specializing in the production of semi-finished wrought iron and finished cast iron that operated almost without interruption between 1734 and 1883. Les Forges first came into being in 1729, when Montreal merchant Franc;ois Poulin de Francheville submitted to the King of France a request for the right to exploit the bog iron ore deposits on his seigneury of Saint-Maurice. This request, agreed to in 1730, was one of a long series of attempts, previously unsuccessful, to establish a local iron industry in the colony. Several such proposals were held up by a lack of capital from promoters or a too rigid application of the mercantilist policy by the metropolis. In 1730, however, the French minister Maurepas favoured a more liberal policy which would encourage private enterprise. The benefits of an iron industry to the naval construction industry was a factor that caught the attention of administrators. The choice of the site for Les Forges was based on the following factors: - the abundance of surface deposits of bog iron ore in the Saint-Maurice region; - the presence of a vast supply of hardwood and conifers needed in large quantities by this industry; - the proximity of sandstone and limestone deposits, md1spensable materials for the construction and operation of the blast furnace; - the presence of a water stream, with sufficient flow to provide the hydraulic power needed for the operation of the machinery.

Jan 1, 1999

By S. Y. Mostowy, P. W. M. Shibley

"When Texas Gulf Sulphur Company discovered the Kidd Creek ore body in 1964, a crash program began almost immediately for the design and construction of a modern concentrator. It was necessary to mill two distinct ore types; one containing copper and zinc, the other lead, silver and zinc minerals. The final concentrator design was to handle 9,000 tons of ore daily in three circuits. One circuit was to treat copper-zinc and another lead-zinc ore exclusively on a permanent basis. A central circuit was designed with adequate flexibility to treat either of the above ore types in accordance with planned mining schedules. Ecstall Mining Limited, a wholly owned subsidiary, now operates the mine and concentrator complexes for Texas Gulf. The mine is located 15 miles north of Timmins and the concentrator 15 miles to the north-east along Highway 101. The ore is hauled from the mine to the concentrator over a 17-mile railroad. Initial milling operations began in November, 1966.1 - ABSTRACTThis paper deals with bulk reagent handling at the Kidd Creek concentrator. The reagent section at Kidd Creek has operated excellently since milling began in 1966. The bulk handling techniques are satisfactory. They have contributed substantially to good working conditions, economical practices and metallurgical efficiencies. The bulk handling features described should be considered in existing and proposed concentrators."

Jan 1, 1970

By Jennifer Pakula

Productivity improvements in underground mining are becoming harder to find. Most mines quickly identify deficiencies in their processes and then struggle to make productivity gains beyond that plateau. One way to increase productivity in this situation is to modify existing methods of operation. Vale?s Stobie Mine has been in operation since the late 1800?s employing a variety of mining methods. Many mining advances have been incorporated over time. With the advent of mechanized rubber tired equipment, sublevel cave mining was introduced to allow economic extraction of a large low grade area. Additional productivity gains were seen in the sublevel cave area with the introduction of preloading production drill holes. In preloading, the holes are loaded with bulk emulsion ahead of the production cycle and then primed for blasting as needed. The introduction of preloading, although giving the Stobie sublevel cave process an overall productivity gain, saw an increase in oversize due to the collar priming technique employed. Handling oversize material prohibited the operators from handling additional units of optimally sized material. Prepriming, adding detonators at the toe and midcolumn of the production holes during the preloading process, was identified as a change that could reduce the formation of oversize. This paper describes the introduction of prepriming to the sublevel cave mining method and focuses on the process Stobie employees followed to ensure a safe transition to this productivity improvement.

Nov 1, 2011

By J. Shahabpour

"Breccias with angular and rounded clasts of a late-mineralization, ""barren"" hornblende porphyry dike set within a comminuted matrix consisting of rock fragments and quartz, cemented by quartz and K-feldspar of hydrothermal origin is observed in diamond drill cores from the Sar Cheshmeh porphyry copper deposit. Studies of age relationship between vein types, phyllic-altered clasts and the breccia groundmass suggest that the brecciation is a late event. The breccia clasts record evidence of hydrothermal reaction between the clasts and fluids responsible for the brecciation.Formation of bornite, in the breccia clasts of the originally barren hornblende porphyry dike, and in the breccia matrix, along with the scarcity of bornite in the Sar Cheshmeh deposit itself suggest involvement of fluids which are later and of different composition from the fluids responsible for the known mineralization at Sar Cheshmeh. These later fluids may be related to a later plutonic event and suggest the possibility of a later, and concealed deposit."

Jan 1, 1994

By E. H. Holm

"This paper is a market-oriented review of the industry's present and forecasted performance, considering some of the principal factors influencing natural resource development. The author illustrates the steady consumption growth of nickel, and stresses the need for a quantitative long-range approach to production, consumption and the supply/ demand balance on a worldwide basis. Objective consideration of this data exposes some popular misconceptions. The possibility of near-term undersupply of nickel is discussed in relation to historically rapid changes in inventories and demand patterns. What is the significance of the increasing reliance on lateritic sources? New• facilities, new processing methods and new product forms are illustrated as further evidence of the industry's determination to satisfy the needs and preferences of nickel consumers. Examples indicate how product forms must accommodate to fast-evolving end-use technology. A review of nickel's price performance is used as a base from which to explore tomorrow's price trends."

Jan 1, 1972

By Chris M. Healey

"Perhaps the single most significant variable in the evaluation of a mining project is the reserve estimate. Many parameters are considered when estimating reserves, among them geology. This paper examines the link between the quality of a reserve estimate and a good understanding of the geological controls for the deposit. A clear understanding of the geometry is essential to the accurate definition of the shape and size of the deposit. This includes the definition of any structural controls as well as the proper interpretation of the stratigraphy. Further when the distribution of grades is erratic and there is consequently a high nugget effect, there are significant problems in estimating the true grade of the deposit.Two Saskatchewan examples are presented, one with good knowledge of the controls and therefore good estimates of reserves, and the other with a poor understanding of the geology and resultant problems in deriving good estimates. In both cases the reserve estimates at various stages in the project development are compared to actual results from underground work. The first example is the Star Lake Mine where just about all the estimates were within 10070 of the actual on both tonnage and grade. The Laurel Lake deposit is discussed to show how problems in interpreting the geological data make reserve estimation very difficult. Laurel Lake has the additional problem of erratic grade distribution."

Jan 1, 1992

By H. C. L. Reemeyer

One of the fundamental trade-offs for copper concentrators is between grinding circuit product size and copper recovery. The capital and operating cost savings and throughput increases for a coarser grind should be evaluated against potential recovery reductions. Other benefits of coarser grinds, such as GHG emissions reductions and favourable effects on tailings and water management should also be considered. This paper assesses the formation of laboratory and pilot test programs, design of process flowsheets, equipment selection, and evaluation methods to determine the most appropriate and economical grind size for a given deposit. The paper will include an evaluation of case studies. INTRODUCTION The majority of the world’s mined copper comes from sulphide deposits, which are mostly processed using crushing, grinding, flotation and dewatering flowsheets to produce copper-bearing concentrates for smelting. Ores must be ground to a sufficiently fine size to achieve an acceptable level of liberation to allow both high recovery of copper and valuable by-product minerals while efficiently rejecting gangue to tailings. Therefore, a key design parameter in process plant design is the grind size of the flotation feed. Copper concentrators use a variety of grind size targets that depend on various factors, including ore mineralogy and the grain sizes of valuable and gangue minerals; the sensitivity of valuable mineral recoveries in the rougher flotation stages to grind size, ore hardness; electricity costs; and mining vs. processing throughput constraints. Typically, copper and by-product recovery increase as grind size is reduced, which can improve revenue, but finer grinds increase power and grinding media operating costs and may have implications for tailings management. This paper explores the trade-offs that should be assessed in determining the optimum grind size, and to answer the question if coarser grinds are worthwhile. METALLURGICAL AND FLOWSHEET FACTORS Recovery-by-size behaviour of sulphide-bearing particles In base metals sulphide flotation, it is typical that flotation recoveries vary by particle size. Metal sulphide particles rendered hydrophobic by collector in intermediate size ranges (e.g. 10 to 100 um) usually show very high recoveries, often approaching 100%. Recovery usually falls away in finer size fractions (<10 um) as fine particles have little inertia and can move around bubbles without colliding and attaching to them. Coarser particles (>100 um) are susceptible to particle-bubble detachment and dropback (Jameson, 2019).

Jan 1, 2019

By Carlos Nieble

Ferteco Mineracao, belonging to the CVRD group, is one of the several iron ore mines in the south east of Brazil. Some of these mines have pit walls of over 350-m height and operations under difficult geo-technical conditions are steadily increasing. In order to mine the 15 million tonnes of high grade hematitic ore remaining in the Fabrica pit, Ferteco had to deal with the following restrictions: Warrant power to its concentrator and pellet plant, relocate the load-out rail road loop, stabilise a poor phillyte slope, relocate a creek on a bench, lower the water table and mine at maximum angles at a slope with phillyte and loose itabirites directly under the rail road loop. Considering these aspects, 3 stages of operations were designed, considering a safe operation, but with the lowest possible security factors at the last mining stage, before the pit would be filled in again with tailings. Stage one above the rail road loop and below the high tension power mast, where the poor phillyte slope was secured by a flexible retaining wall, using old rails and anchors up to 27 meters (80ft) with a working pressure of up till 30 tonnes and stage two with different slope angles, and deep wells, high wall blasting perpendicular to the highwall with relief holes and rerouting the creek in steel half culvert and stage three, the filling in with tailings and recuperation of the deep well pumps. Following studies and analysis were made: Geotechnical and geological studies of all rock formations including rock strength test, a hydrological study to define the lowering of the ground water level, slope stability analysis for every bench and all possible combination of benches, definition of blasting parameters close to the pit slope, a monitoring plan, including topographical movements, vibrations due to blasting, piezometers and pressure cells as well as a plan how to fill up the pit again with tailings in combination with the rising of the ground water level. A close co-operation between the geo-technical consultant, pit operations, the blasting contractor and the geological department resulted in an operation without any incidents, lowering the pit with an additional 3 benches and mining an additional 5 million tonnes of high grade ore.

May 1, 2003

By Michael K. Watkeys, Jacobus E. Potgieter, E. Guy Charlesworth, Carl R. Anhaeusser, Roger L. Gibson, Alexander F. M. Kisters

Intrusive features of cupriferous noritoids from the deeply eroded Proterozoic granite-gneiss terrane of the Okiep Copper District in South Africa illustrate the emplacement of basic magmas into a mid- to lower-erustal environment. The small, easterly trending intermediate to basic intrusions of the so-called Koperberg Suite display a wide variety of geometries, occurrence and emplacement modes, including dike-, sill- and plug-like bodies. Coeval granulite-facies metamorphism, partial melting and ductile deformation of country rock gneisses during intrusion of the basic magmas led to emplacement and dilation processes of the intrusions which differ significantly from those described for dikes and sills at shallow crustal levels. Regional tectonic stresses are largely negligible due to very low differential stress [( )] during deformation and intrusion, which permits emplacement at high angles to the principal compressive stress and which follows favorably inclined structural anisotropies. Dilation of the basic intrusions is largely determined by compositional differences of host rocks and occurs by thermal erosion, i.e., assimilation of wall rock gneisses. Low length-to-width ratios of basic to ultrabasic dikes and predominantly diapir-like outlines of mesocratic bodies are indicative of low viscosity contrasts between the mafic magmas and high-grade metamorphic host-rock gneisses. Buoyancy-controlled ascent of the basic to intermediate intrusions is expressed by a broad compositional zoning of basic bodies with respect to the granite-gneiss stratigraphy. Various intrusion modes within the stratigraphic column of the granite-gneiss sequence reflect a lithological and structural stratification of the seemingly homogeneous granite-gneiss terrane.

Jan 1, 1994

By Robert Walker

Agenda ? Investment thesis ? Engagement ? Competitive advantages Corporate engagement ?The ESG Services team carries out engagement activity with the companies in the Ethical Funds portfolio on behalf of investors ?Each year about 50 companies (20% of our assets) are placed on our Focus List based on assessment of significance and severity of ESG risks and the extent of our portfolio exposure ?We engage in direct discussions on material ESG issues ranging from climate change to human rights to executive compensation ?This enables the team to gain insight into how management is addressing various risks to the business and encourage positive change where gaps exist

Aug 1, 2013

By H. E. (Buzz) Neal

"Abstract - The Labrador Trough contains world-class iron deposits which have been mined since 1954. The direct shipping of Knob Lake ores were mined at Schefferville from 1954 to 1982. Concentrate production began in 1961 in the southwest end of the Trough, with three mines currently producing concentrate and pellets at a rate of 35 Mt per year. West and north of Schefferville, several billion tonnes of taconite have been outlined in fine-grained, cherty magnetite iron formation. Several deposits of highly metamorphosed magnetite-specularite iron formation are located west of Ungava Bay. Numerous studies have shown that this medium- to fine-grained iron formation can be beneficated to 66% to 68% iron. In the area from Wabush Lake to Mont-Wright, a medium- to coarse-grained friable specularite-quartz iron formation is repeated by folding to form several large deposits. In this area, three mining operations are located with reserves and resources in the order of 5 billion tonnes.The iron deposits occur within iron formation in sediments in the extensive Proterozoic geosyncline called the Labrador Trough. Several facies of iron formation within the Sokoman Formation reflect variations in chemical composition and depositional conditions. The correlation between the mineralogy and textures is discussed to illustrate the development of different types of iron ores. This band extends for about 1100 km southeast of Ungava Bay through both Quebec and Labrador. Further south, it turns southwest past the Wabush and Mont-Wright areas to within 300 km of the St. Lawrence River. The iron formation is essentially folded and faulted along most of its length. The degree of metamorphism is variable, ranging from intense in the northern and southern portions to greenschist facies in the central portion.The stratigraphy, structure and mineralogy of the producing mines are described along with the history of discoveries. Geological input is required to achieve the strict specifications of the international iron ore market."

Jan 1, 2000

By J. A. Meech

"The technology known as Expert Systems is being used within the minerals industry in a wide variety of problem areas. Applications include diagnosis, prediction, training, monitoring and control. Expert Systems provide a way to program computers to imitate human thinking. The construction of such systems is a straight-forward task that can be quickly learned by novices but can require a lifetime to master.To assist in the understanding and utility of this technology, a special manual bas been prepared which operates on a microcomputer under the MS-Windows environment. The manual covers all aspects of Artificial Intelligence of relevance to Expert Systems. A hypertext system allows users to probe as d•~ply as needed to achieve understanding or to simply skim the surface of the knowledge to obtain a quick overview of subjects. The manual was developed under the sponsorship of the Mineral Sciences Laboratory of CANMET and is available from the Mining and Mineral Process Engineering Department at the University of British Columbia. Annual updates are planned to keep abreast of new developments in this rapidly changing technology. RESUMELa technologie: des Systèmes Experts est utilisée par l'industrie minière pour résoudre une grande variété de problèmes. Les domaines d'application comprennent le diagnostic, la prédiction, la formation, la surveillance et le contrôle des procèdes. Les Systèmes Experts permettent d'écrire des programmes d'ordinateur qui imitent le processus de la pensée humaine. La construction de tels systèmes e:st une tâche qui peut être apprise rapidement mais qui peut prendre des années à maitriser.Pour aider à mieux comprendre et utiliser cette technologie, un manuel spécial opérant sur microordinateur dans l'environnement Windows a été développe. Le manuel couvre tous les aspects de l'intelligence artificielle qui concement les Systèmes Experts. Un système ""hypertexte"" permet à l'utilisateur d'étudier un sujet en profondeur ou de simplement couvrir une grande variété de sujet en surface. Le manuel a été développe avec l'aide financière du Laboratoire des Sciences Minérales de CANMET et est disponible au Département de Génie Minier et Minéralurgique de l'Université de la Colombie Britannique. Des mises à jour annuelles sont prévues de manière à couvrir les changements et nouveautés de cette technologie en évolution."

Jan 1, 1993

By M. Remillard, M. Garon, M. Thérien, D. Hodouin

"Nineteen streams in the copper and zinc flotation units of the concentrator of the Matagami division of Noranda Inc. have been sampled for particle size distributions chemical assays, and gold and silver contents in each particle size interval. The data are upgraded by the mass balance package BILMAT. These results, in conjunction with microprobe analyses, are used to quantify the silver losses in the copper clean¬ing flotation stages and to determine how overall silver and three silver-bearing minerals are recovered in the plant final products.RESUME Dix-neuf produits des circuits de flottation du cuivre et du zinc de la division Matagami de Noranda Inc. ont été échantillonnés pour leur distribution granulométrique, analyses chimiques et le contenu d'argent et d'or des fractions granulométriques. Le bilan métallurgique a été obtenu à l'aide du programme BILMAT. Ces résultats couples avec une etude minéralogique à la microsonde sont utilises pour quantifier les pertes argentifères aux diverses étapes de nettoyage du circuit de cuivre et pour de¬terminer la repartition de l'argent et des trois minéraux argentifères dans les produitsfinals de l'usine.INTRODUCTION The Matagami division of NORANDA INC. produces copper and zinc concentrates from a sulphide ore which contains a small amount of gold (0.34 g/t) and silver (20 g/t). Only a small part of the silver (~-30%) is presently recovered in the copper concentrate. The objective of this study is to evaluate the metallurgical behaviour of silver, and secondarily of gold, in the flotation circuit for a possible increase of its recovery in the copper concentrate to improve its economic value. For that purpose it is worthwhile to study the minerals which bear silver and to determine the critical flotation stages where they are lost in the tails. The methodology proposed here is based on a coupling of a mineralogical study and a detailed mass balance calculation in the flotation circuit."

Jan 1, 1986

By R. Alarcón Sch., R. Abel F.

For many years, copper cathode quality has been a priority for end consumers, since it affects the variety of products that can be obtained from them. From the beginning, physical and chemical quality of the wire bars was controlled, as this product was used to obtain wire rod and other forms of copper by wire drawing. At that time, all the electro refined cathodes were melted and casted as wire bars. Subsequently, in the 80’s, with the introduction of continuous casting furnaces, it was possible to directly produce wire rod from cathodes. From then on, cathodes quality standards were consistently increased, by the introduction of uniform criteria, among which we can identify ASTM and British Standards as well. Also, producers began to use more demanding internal standards than the existing specifications, in order to differentiate their cathodes as high quality products among customers. Today the physical aspect of cathodes, including nodules, cracks, sulfates, or others, is the first element used by end customers to assess their quality. This paper aims to show a brief vision of the evolution of quality specifications for products used to manufacture copper wire. INTRODUCTION From the beginning of refined copper production for industrial purposes, mandatory minimum quality conditions were established. These quality conditions were used as the main element to determine prices and discounts of the respective sales contracts. Reviewing the copper development history, we can appreciate that its quality requirements had been constantly evolved, so that currently refined copper has an extremely high quality standard, that allows its direct use in the production of ultra-thin cables and other products applied in the industry. In each stage, refined copper production has fostered the development of technology used in their treatment. Similarly, cathode processing technology has been evolving to minimize treatment costs in order to generate a wire rod for several uses, ranging from power cables to super conductors. In this sense, to the already known type of fusion processes of the Southwire or Asarco type (capacities over 80 kt / year), wire rod production processes of the Upcast or Rautomead type (capacities between 20-50k t / year) have been added. They immediately deliver oxygen-free wire rods. In both cases, we can conclude that the clients' requirement had evolved from a chemical criteria focus, to considering more subjective aspects, such as visual control as the first stage of inspection.

Jan 1, 2019

By Simon C. Dominy, Ian M. Platten

"Abstract - Gold-bearing quartz reefs commonly show extremely erratic and unpredictable grade variation, although gross geological continuity may be good. This type of variation is often described as being nuggety or having a high nugget effect and can be measured quantitatively using the semivariogram. Understanding of geological features such as reef texture and structure will provide improved models for the interpretation of assay data, drill core descriptions, etc. In this paper, a case study from the quartz-hosted gold occurrences in the Gwynfynydd mine, United Kingdom, is described. The work provides a starting point for models of lateral variation and demonstrates the types of structural and textural features that may be sought to give clues to the prediction of gold distribution in similar deposits. Gold deposition at Gwynfynydd is primarily associated with the reef footwall. The host veins form a discrete group of structures that may have been emplaced early in the sequence of quartz veins forming the reef. This potentially exposes them to a maximum number of dissection events during repeat dilations of the lode. Gold was deposited in the local porosity at extreme concentrations, equivalent to kg/t grades, when the host fissure had become filled with a porous framework of crystalline quartz and sulfides. Distribution of porosity varied laterally along the vein as the result of the formation of clump-like growths of minerals from the vein walls. The growth style is relevant to the distribution of gold although it may not be relevant to the occurrence of gold in a particular vein. The preservation of pores with some connectivity late in the vein fill sequence may be important in permitting continued but slow fluid flows. This facilitates effective fluid reaction with wall rock-derived methane, thus changing the relative rates of gold and quartz deposition in favor of gold. The textural studies explain the first-order control of nugget distribution at Gwynfynydd but do not allow for prediction and optimization of the resource estimation process. This is principally because of the very low geological continuity and poor predictability of the high-grade pockets. Nonetheless, the work does provide a clear geological explanation for the erratic nature of the gold. It indicates textures and structures that can be used to determine geological continuity of the goldbearing elements within the gross reef envelope."

Jan 1, 2001

The reliability of mining systems is generally low due to their harsh working conditions. Currently, efforts for improving mining system reliability are often made in isolation. This practice could substantially limit the effectiveness of the efforts on overall reliability improvement of the mining system. To enhance the overall reliability of mining systems, an integrated improvement approach is necessary. In this paper, we developed a framework for integrated mining system reliability improvement to address this issue. In this framework, there are five major components including data integration, business process integration, hardware integration, software integration, and analysis/decision integration, but we only focus on the integrated reliability analysis which is important to the analysis/decision integration. The reliability analysis considers the interactions between machines, and the impacts of design, operation, maintenance, automation and working environment on the overall system reliability. These multiple interactions present a big challenge to accurate reliability prediction. In this paper, we for the first time systematically investigated integrated reliability analysis approaches for dealing with this challenge using novel models and methods, including covariate hazard models, intelligent reliability prediction approach, and complex system modeling methods. While these models and methods have found some successful applications in other industries, they in general have not been effectively used for the reliability analysis of mining systems. Our study results show that the system integration approach is applicable to mining systems and can be used for developing a computer aided integration system for the implementation of the integrated reliability improvement approach.

Aug 1, 2013

By G. W. H. Norman

The surficial Archæan rocks of the southern gold belt of western Quebec are constricted near Kewagama lake by granite masses to the north and south. This divides the belt into natural eastern and western parts. This paper deals with the eastern part, extending from Malanie to Haig township. In this section the Keewatin-Timiskaming rocks have a length of about 70 miles and end abruptly against garnetiferous gneisses of the Grenville terrain. In the western half of the section where exploration has been under way since the early twenties, there are sixteen mines that are or have been in operation, and eleven prospective mines. In the eastern half where exploration has been carried on since the early thirties, six prospective gold mines are under development, one· of which, Louvicourt Goldfields, is at the initial production stage. Of the sixteen properties in the western half that are operating or have operated, all, except the Golden Manitou, which is a base metal mine, and the old Green Stabell from which there was a small production of copper, produce gold. Of the eleven prospective mines in the western half nine have gold. New Bidlamaque has gold and copper and one, East Sullivan, has copper-zinc ore. Since production began in 1927 gold, silver, zinc, copper, and lead having a total value of about $10,000,000 have been produced from the mines of the eastern section of the southern gold belt of western Quebec.

Jan 1, 1954

By J. L. Bowlby

TWO years ago, at the annual meeting of this Society, the writer presented a paper dealing with various aspects of the water problems existing in the Cape Breton coal-mining area. Much of that paper was of a theoretical nature, in that an attempt was made to get at the fundamental principles underlying the problems, in order to establish a sort of background against which future results could be laid. Up to that time, only Central power plant in Glace Bay had been under observation, and, since the work had been in progress only a year, it was recognized that there were strong possibilities that certain variations in procedure might have to be introduced as w; became better acquainted with our problem. We were by no means certain that we had covered all the facts of the case. The present paper will therefore be of the nature of a progress report, rather than a formal contribution to the Society. Subjects of a theoretical or academic nature will be avoided as far as possible, attention being confined chiefly to the results obtained during the past two years. In looking over the work with low-pressure boilers, there are certain general conclusions that can apparently be safely drawn. Wherever possible, proper operating conditions will be expressed in terms of appropriate units. Absence of corrosion in boilers where the alkalinity has been maintained within the pH range 11.0 to 11.4 forces one to the conclusion that these are safe working limits. Previous experience had shown that corrosion would occur if the alkalinity were much reduced. Higher alkalinities are un-necessary, more expensive, and are said to introduce the possibility of pitting. We made no attempt to obtain quantitative data in respect to pitting. It is said to occur at pH 12.0. Consequently, conditions of alkalinity were main-tained well below this figure. In the above paragraph, the pH range 11.0 to 11.4 applies to boiler waters which have received the lime and soda treatment. The general practice, when this treatment is employed, is to use 1.0 lb. lime to 7.0 lb. washing soda. At Central power plant, soda-ash is at present substituted for washing soda, the equivalent proportions being kept the same. But not all the plants are on the lime and soda treatment. At Waterford Lake, a 1: 1 mixture of soda-ash and trisodium phosphate is satisfactorily employed, and in Sydney Mines and at No. 3 power plant in Sydney, good results are being obtained at a somewhat greater cost with a commercial phosphate treatment.

Jan 1, 1936