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By J. C. Loretto

"OPENING REMARKS Yesterday and today we have heard some very interesting papers on operating matters and some of you are probably wondering what we are now doing talking about Communications in Plant Design. Let me tell you! Before the techniques we have heard being discussed can be used, there has to be a properly operating plant. It is certainly a fact that many mineral processing plants achieve only limited success and a number of them can even be said to be failures. Some of you sitting here are probably living with operating problems that are clue to errors in the design.If the histories of these problem plants are examined, it will be found that in many cases, the necessary skills were available during the period of the plant design. There was extensive operating know¬ledge together with a full range of project expertise. Why then the failures? In a substantial number of cases it can be traced to the old, old problem of communications. As plants get bigger, money costs more and smooth startups become more important, it becomes less and less economic to fix up any design errors during plant operations.During our careers in mineral processing, nearly all of us will be involved in at least one plant design and I feel that it is as well if we understand some of these communication difficulties that can lead to a problem plant. There is little point in us being experts in mineral processing if the knowledge we have acquired doesn't somehow get incorporated into the plant.I would, therefore, like to present this short paper that mentions a few of the significant communication problems that can occur during the design of mining and mineral processing plants, together with some thoughts on answers to these problems."

Jan 1, 1973

By Matthew Violot

Vale Canada?s Birchtree Mine, located in Thompson Manitoba, has been experiencing problems with hanging wall / footwall dilution, as well as sloughing off of adjacent stopes and temporary stope block backs. Birchtree Mine is interested in determining how time affects the stability of their open stope blocks. Many factors simultaneously influence open stope stability (rock mass quality, joint condition, stress condition). This makes it challenging to determine the influence of a single parameter such as exposure time or stand-up time. This study focuses on determining the effect of exposure time on open stope dilution and combines stress analysis and empirical based approaches.

Jun 1, 2012

By B. R. Boardman

Project Environmental Approval is a multi-faceted issue. From a mining perspective, it is a costly item because of avoidable time delay. The government perspective is that the approvals are a necessary part of meeting departmental requirements to ensure that the wellbeing of other uses of the environment is maintained. This paper outlines some of the problems inherent in the environmental approvals process and makes recommendations to both the proponent and government about improving the efficiency of the process.

Jan 1, 1978

By Brian L. Beninger

This paper discusses the application of the computer to coal preparation process predictions. In broad terms, the computer is used to perform two main functions. Firstly, the given float-sink analysis is interpolated and extrapolated to cover the entire actual range of raw coal specific gravity. Assumptions based on historical data must be made at times. Secondly, the partition curve, which, from historical data, defines the efficiency of a specific coal washing process, is applied to the washability data in order to determine the expected clean coal yield and quality. The vast amount of numerical work which is required to make a prediction of this type exhibits the need for computer methods in this area.

Jan 1, 1979

By C. O. Brawner, J. Kalejta II

"The classical approach to control rock fall and ravel in open pit mining has been to use catch benches. The width and volume of benches is most dependent on the bench height, size of loading equipment, blast damage to the face and mining regulations. This was compatible with open pit slopes of less than approximately 45 degrees.As our understanding of rock mechanics and blasting control has improved over recent years, much steeper rock slopes can be developed at many open pit mines. However, narrower benches result in less rock fall capacity.The transportation industry has been very successful in using catch fences to protect highways throughout North America and Europe for years. The authors recommend that cable and ring net fences have a potential major application in open pit mining to allow steeper rock slopes with significant economic benefit. This paper outlines the application, design and operation of catch fences in surface mining for specific conditions. Typical case examples are presented."

Jan 1, 2002

By J. W. Craig

CHROME ore, which is used in Canada in the production of ferro-alloys, in a variety of refractories, and indirectly in many chemical industries, is both commercially important and scientifically interesting. The sight of chromium metal is familiar to all of us in the home, the office, the automobile. Chromium is synonymous with armaments: it is understood to be one of several essential metals in tanks, which played an important role in the defeat of France in the spring of 1940. Chromium, in other forms, comes into our daily lives by way of paint and leather, of the familiar green ginger-ale and beer bottles, and more indirectly in every pound of steel produced in the .Dominion. Necessary to our civilization in peace and war, the ores of chromium occur in many corners of the earth. This paper attempts to describe the chemical constitution of chrome ores, their world distribution, and the various chrome products and their industrial applications in Canada.

Jan 1, 1940

By Joseph B. de Hart

Two papers recently published on the subject of mine ventilation: "The Theory of Ventilation," by Douglas Hay. and "The True Effect of Natural Ventilation in Deep Mines," by Robert Clive, form the first and second reports respectively of the committee on the Ventilation of Mines appointed by the Midland Institute of Mining Engineers. The purpose of the present paper is to draw attention to these two papers and the discussion thereon. The theory of ventilation as taught in our schools is based on Atkinson's formula, which is a variation of Chezy's formula for the flow of water in pipes. The formula depends on two assumptions : 1. That air is an incompressible fluid within the limits ordinarily encountered, and; 2. That the pressure required to produce ventilation varies as the square of the rate of flow. The Atkinson formula has been assumed to hold good over the entire range of conditions met with in mines.

Jan 1, 1924

By Norman Marr

Introduction In Canada, the mining industry and water-power development are intimately associated in that mining, which ranks second among the country's primary industries, depends principally upon hydro-electric energy for its large power requirements. On the whole, the Dominion has been very favourably endowed with water-power resources; generally speaking it is a well-watered country with numerous rivers and lakes located in are as where the topography favours water-power development. Precipitation, the raw material of water power, varies from an annual fall of more than l00 inches on the Pacific coast to about 12 inches in sections of the Prairies and the Northwest Territories; in Ontario and Quebec the annual average is 24 to 40 inches and in Nova Scotia about 45 inches. In its descent to the sea, the resulting run-off, much of it from considerable altitudes, creates sources of potential energy at every rapid and fall along the country's many streams and rivers. Many of the innumerable lakes in the Dominion provide storage basins for the regulation of stream flow, thus enhancing the potential power of available sites. While water-power resources are fairly well distributed across the Dominion, as is shown on the accompanying map of Canada showing power sites (Figure 1), it is particularly fortunate that those areas which are lacking in indigenous fuels have been compensated in large degree for this scarcity by being favoured with a high proportion of the total potential water power. This has an important bearing on the mining industry in that extensive mining operations can be economically carried out in the great Canadian Shield, which is lacking in commercial coal deposits but is rich in water-power resources. This Precambrian formation, which forms a wide belt around Hudson bay and in which many metalliferous ores are found, was 'subject to severe glaciation in a recent geological period, so that its river systems are comparatively young and are characterized by numerous lakes joined by short reaches of fast water, rapids, and falls which offer frequent opportunities for power development. The western Cordilleran region, which also is important in mining, has abundant water power. The accompanying geological map (Figure 2), prepared by the Geological Survey of Canada, shows the great extent of the Precambrian and Cordilleran regions and may be compared with the map of water-power sites to show the high incidence of water-power resources in these potential mining areas in which important mineral discoveries have already been made.

Jan 1, 1949

By W. H. Stheeman

"The high rock pressures at the deeper levels of the Tsumeb Mine have necessitated the changing of the mining methods and the introduction of cable bolts. After two rockfalls in the cable-bolted stopes, the mechanics of cable bolting were investigated. Practical methods were developed to find the best grout mixtures, the bond stresses between cables and cement, the bond stresses between rock and cement and the load on the cable bolts, which was mathematically calculated from data observed underground. The design of the cable bolt support system as used at the Tsumeb Mine is explained. GeneralThe Tsumeb Mine is in northern South West Africa/Namibia, approximately 400 km by road from the capital city, Windhoek, at an elevation of 1300 m above sea level. Mining operations in Tsumeb were started in 1905 by the Otavi Minen und Eisenbahn Gesellschaft and continued, with an interruption during the Depre ssion, until 1940, when the mine was closed and taken over by the Custodian of Enemy Property. The present owner, Tsumeb Corporation Limited, obtained the mine in 1947 and restarted the underground mining operations in 1949 after the mine was dewatered. Currently, the stoping operations are between 26 Level (840 m below surface) and 38 Level (1260 m below surface). In addition, the mine is an important silver producer and has produced 670,100 kg of silver since 1947."

Jan 1, 1982

By G. S. Dobby, J. A. Finch

"A significant development in froth flotation technology has been the emerging industrial acceptance of column flotation during the past few years. Flotation columns are being employed now in several Canadian base metal concentrators and they are being considered f or a wide range of flotation applications throughout North and South America. Since the operating principles of a column differ markedly from those of conventional flotation machines, and have been poorly understood, scale-up of columns has been difficult. This paper describes a methodology f or translating laboratory column data to industrial operation.The scale-up model utilizes kin etic data that is obtained from a series of laboratory column experiments; the laboratory column can be as short as 2 m. For modelling purposes the column is considered to consist of two zones: the collection zone, where particle recovery occurs, and the cleaning zone, a packed bubble bed generated by downward flowing wash water. Mixing conditions in the collection zone have been characterized using the results of tracer experiments on plant columns at Mines Gaspe. The same experiments demonstrated the nearly complete suppression of entrained gangue minerals that is attained in the cleaning zone. The model explicitly accounts for both the collection zone and cleaning zone recoveries and allows for the effects of bubble overloading. Results of column scale-up experiments at Gibraltar Mines are presented."

Jan 1, 1986

By H. Vendette, N. R. Dando, A. Moras

The thorough analysis of results obtained from different testing campaigns performed on an alumina dry-scrubber pilot installation treating aluminum potline offgases, suggests a clear relationship between the emissions of gaseous fluoride and the fluoride saturation level of the alumina. The integration of this relationship into the development of a new generation of alumina dry scrubber represents an intriguing challenge regarding the design of more efficient air pollution control equipment. An innovative scheme challenging conventional industry practices was proposed. From theoretical simulations, the reduction in fluoride emissions can potentially be reduced by as much as 50% in the summer season. To validate this innovative approach, Solios in partnership with Alcoa Primary Metals, modified one of the Aluminerie de Deschambault's systems by adding new temporary equipment on the operating units and subjecting it to several test campaigns. This article presents the first results obtained in testing this new and innovative approach on alumina dry scrubbers used to capture fluoride emissions coming from aluminum electrolysis potlines.

Jan 1, 2006

By S. Banisi, M. Pourkani, A. Kargar, D. Hamidi, M. Sarvi

"Flotation circuit of the Sarcheshmeh copper mine, which processes 40,000 t/d of ore at 0.9% Cu, consists of rougher, cleaning and recleaning stages. To study the stage recovery of copper, one of the eight identical flotation banks was selected for sampling. It was observed that 17% of copper goes to the tailings and the lowest copper recovery was for particles coarser than 105 microns. The third five-cell unit of this bank not only did not recover appreciable amount of copper but also decreased the concentrate grade. The grade of the last five cells was lower than the feed grade suggesting that mixing of the concentrates of the three units was not beneficial. To alleviate the problem, the concentrate of the first four-cell unit was directed to the cleaners feed box (i.e., by- passing the regrind mill). This increased the overall copper recovery by 1.7 %. Also rather than the current practice of adding the reagents only at the feed tank (i.e., 100-0-0%), various combinations of stage addition were examined. It was found that 75-25-0% addition regime could increase the total copper recovery by 1.3%. At the recleaning stage in order to increase the final copper concentrate grade, a froth washing system was used. To ease the maintenance of the system, a shower type washing system was installed. The optimum wash water superficial flowrate was found to be 0.06 cm/s. Continuos sampling of the recleaners with and without wash water over a period of two months showed an increase of 1.5% in the final copper concentrate grade at constant overall copper recovery.INTRODUCTIONThe Sarcheshmeh copper ore body that may rank as third or fourth largest in the world contains 1 billion tonnes averaging 0.9% copper and 0.035% molybdenum. It is located in southeastern Iran and has been processing 40 000 t/d of ore since 1982. The mine produces 100 000 tonnes of copper and 2200 tonnes of molybednite concentrate per year.After three stages of crushing, the ore with a F80 (80% passing size) of 12.7 mm is fed to eight parallel ball mills in closed circuit with cyclones to produce a product 70% finer than 75 microns. The concentrate of rougher flotation circuit is ground; rougher tails constitute the main component of the plant final tailings. A concentrate with an average grade of 31% Cu (chalcocite and chalcopyrite) is obtained after cleaning and re-cleaning stages. Total recovery of the plant varies between 83% and 87%, depending on operating conditions and ore type."

Jan 1, 2001

By N. M. Soonawala

Detailed regional geophysical and geochemical surveys, ground surveys and drilling were undertaken to follow-up the federal-provincial Uranium Reconnaissance Program (URP) over the 27,OOO-km2 Kasmere-Munroe area in northwestern Manitoba. An analysis of the URP data showed a fair correlation between the regional airborne radiometric results and lake-bottom geochemical results, both of which also correlated with the regional geology. More detailed surveys defined anomalies with greater precision within the broad zones outlined by the URP. The ground follow-up indicated that URP anomalies can be caused by varying degrees of uranium concentration in the rocks. Mineralization of interest was found in leucogranites at several locations within the survey area. Anomalous uranium concentrations were also found in coarse pegmatites and Hudsonian granitic intrusions. It can be concluded that large-scale regional surveys can be followed up in relatively short periods of time to yield meaningful results if a properly planned exploration sequence is employed, each stage of which successively narrows the area of interest.

Jan 1, 1979

By Christian Brits, Bob Blain, Lloyd Buckingham, Juliu Stieger, Jean-Francoi Dupont

Barrick Gold Corporation (Barrick) has undertaken innovative methods of evaluating and improving the performance of grinding mills in several of its operations around the world. The results have been positive with some of the mines showing more than 20% net energy improvement leading to more than 43,000 tonnes per year reduction in CO2 emissions in four of the operations reviewed.

Jan 1, 2012

By G. K. Mann

Fragmentation analysis of blast or crushed rock material is a time-consuming and costly process. During the last two decades, the mining industry has been investigating image-based analysis systems as an alternative to generate fragmentation results. Many image-based techniques and commercial products have emerged during the last few years, and the mining industry has recently begun using these tools for real-time estimation of size distributions. Some existing systems require manual image editing to add or delete edges (or net) before executing the fragmentation analysis routine. This manual procedure may take hours of time for each image analyzed. Reliable and robust image segmentation should be able to handle a wide range of rock textures and sizes under a variety of lighting conditions. This paper describes a novel software application, which has the capability to autonomously capture images and analyze them to generate the particle size distribution. The system can also process a batch of images captured during a fixed duration of time and produce the overall particle size distribution. The new method has different layers of segmentation modules, which allows the system to operate under a wide range of rock textures and lighting conditions. A new grey-level slicing technique is developed which can perform under a range of illuminating conditions. The Canny-based edge detection technique is used to segment rocks appearing in dark regions.

Jan 1, 2006

By Peter A. Hacquebard

"The coals of the Sydney and Pictou coalfields are generally classed as high volatile ""A "" and medium volatile bituminous coals but there are significant differences within and even beyond this rank. These are related to the observation that the coalification in eastern Canada is essentially post-deformational, resulting in a general increase of rank with depth in individual seams.Exploration drilling in the Sydney coalfield has shown that the rank increases offshore to M. V. bituminous at mineable depths and in the Pictou field to L. V. bituminous coal. There is also a marked easterly shift in rank within one seam at the same depth at Sydney, with the result that M. V. coal will be reached sooner in the Donkin Reserve area (at 700 m depth) than in the Lingan-No , 26 Reserve area (at 900 m depth). These rank changes are important for the manufacturing of metallurgical coke as shown with coke stability predictions based on petrographic analyses. The L. V. coal of the Pictou field can be used for blending purposes and is the only known L. V. deposit of mineable thickness in eastern Canada.In addition, the vertical rank changes between seams have been studied in ten boreholes. They are not constant within the confines of the Sydney coalfield. Four separate areas can be recognized, each with different coalification gradients, which can be related to changes in the paleogeothermal gradients . Variations of 2.5 degrees to 6. 7 degrees CI IOO m are indicated and geological causes for these changes are suggested.IntroductionThe Sydney coalfield is the largest and most important field in eastern Can ad a, and although it has been in production some 200 years, the remaining ""demonstrated "" resources of 1.6 billion metric tons can extend its production capability for at least another 100 years. All coals mined are high volatile "" A"" bituminous and have been used for both thermal and metallurgical purposes. For the latter rank variations even of a minor scale are of critical importance for the manufacturing of metallurgical coke.The significance at the present time of the Pictou coalfield, which has only modest remaining "" demonstrated"" resources of 60 million metric ton s, lies in the discovery in 1975 of a 14-million-ton deposit of low volatile bituminous coal. It is the only known low-volatile coal in eastern Canada and is suitable for use as a blend for metallurgical coal. As such, it could supply the Sydney coke ovens for a period of 30 years at the current rate o f coke production and replace imported American low volatile coal.Consequently, coal rank studies of the Sydney and Pictou fields are important not only from a geological point of view, but also because of economic considerations."

Jan 1, 1984

By M. U. Savich

In Canadian mines, ear muffs are now an essential part of safety equipment. Because of this, a research study was conducted to investigate their efficiency. The main characteristics of eleven commercially available ear muffs were investigated in the laboratory and analyzed by: (I) a psychophysical method; and (2) a physical method. These investigations showed the following effects: head size has a significant influence on the attenuation because of a different clamping force; the amount of hair trapped between the ear muff cushion and the head decreased ear muff attenuation; attenuation and comfort are not in a causal relationship; with the use of glasses and their adapters, attenuation decreases-the adapters are not effective sound barriers; there are no great differences in attenuation with neck movement; the efficiencies of various brands of ear muffs are not equal; ear muffs with a small cushion area start serving their purpose more quickly because the force per unit area is larger; a clamping force larger than 900 g wt, in most ear muffs, does not cause an increase in attenuation; attenuation characteristics (ANSI 224.22 - 1957) of ear muffs show some correlation with physical tests. Nine ear muffs out of the eleven were tested under uniform conditions in mines. Three ear muffs were found to be the best. All three ear muff s have bands passing behind the head. The ear muff with a support strap, which improves comfort and maintains a good fit during wear, showed the best attenuation. Causes of poor attenuation are numerous: bad mounting of ear muffs on helmets, improper fitting, interferency by hair and glasses, improper wearing by miners, unsatisfactory enforcement by supervisory personnel, incomplete training of miners, etc. Results of this research have indicated that none of the ear muff s tested in this study contain all of the characteristics desirable in an ideal unit. Because of unsatisfactory ear muff attenuation in working conditions (/5 dBA), it should be a mandatory requirement that workers wear both ear muff s and ear plugs if the noise level is higher than 105 dBA (various literature recommends t io dBA). The key to the solution lies in the following: the foreman must be capable of helping and controlling miners in their task of wearing ear muffs properly; the program must be introduced to miners; and constant contact must be maintained with manufacturers.

Jan 1, 1979

By M. K. Abel

"The Strathcona Mine is located in Levack Township on the North Range ofthe Sudbury Basin. The main orebody consists of pyrrhotite-pentlandite-chalcopyrite mineralization associated with an embayment of the footwall of the Sudbury Irruptive. A zone of massive chalcopyrite-cubanite-pentlandite mineralization occurs in a complex vein system in a series of mixed gneisses and breccias in the footwall. Vein widths vary from a few millimetres to 6 metres. In December 1979, this zone was estimated to contain 976,000 metric tonnes, with a grade of 9.31% Cu and 0.46% Ni. The vein system has a general strike of N 68°W at an angle of 60 degrees to the average strike of the footwall contact of the Irruptive. The dip of the vein system is 45 degrees sw. The strike and dip of individual veins in the system coincide with the directions that would result if a compressive stress had acted in a direction normal to the footwall of the Sudbury Irruptive, producing a conjugate set of fractures. The strike of the Irruptive at the Strathcona Mine is parallel to the long axis of the basin.IntroductionThe Strathcona Mine, owned and operated by Falconbridge Nickel Mines Limited, is located in Levack Township on the northwest rim of the Sudbury basin (Fig. I) . It is one of a group of nickel-copper sulphide ore deposits present along an 8.2-km section of the North Range of the Sudbury Irruptive. In the mines of the North Range, subunits of the Irruptive, going from hanging wall to footwall , include felsic norite, dark norite and dark norite breccia. The footwall complex at Strathcona includes the late granite breccia, which hosts a large proportion of the nickel-copper ores, and a compositionally variable group of brecciated and migmatized rocks, herein referred to as the feldspathic gneiss complex. It is within this latter group of rocks that the vein system of the Copper Zone occurs."

Jan 1, 1981

By Mario Bureau

Need for a lab assembly reaching better and consistent static anchorage capacities

May 1, 2013

By G. A. Bezuidenhout, J. Davis, S. Lefume, J. P. T. Kapusta, D. K. Chibwe

"Although the centennial of the Peirce-Smith (PS) converting process has recently been celebrated, the technology has essentially not changed much since its inception. PS converting is used extensively in the Cu, Ni and PGM industry to remove iron and sulphur from a molten matte phase. A typical PS converting process would use low pressure air supplied by a blower to bubble air through the molten bath. This bubbling injection regime is inherently inefficient from a process and energy consideration. In the late 70’s and early 80’s, Brimacombe and co-workers demonstrated at both laboratory and plant scales that sonic injection (jetting regime) into copper or nickel converters could reduce or eliminate the above hindrances characteristic of PS converting. Since then, in spite of these successes, very little industrial applications have made headway in the converting process of non-ferrous metal mattes on a commercial scale. As part of its operational improvement and energy reduction program (process efficiency), Lonmin Platinum decided to conduct a full scale industrial evaluation of sonic injection using air only to establish if punchless, high efficiency sonic injection was feasible in its small 3.05 × 4.57 m converters (10’ × 15’). A plant trial was run for four weeks in one of its three converters. This paper discusses the plant demonstration with a focus on the experience acquired by Lonmin together with the key learnings from the trials. Reference will also be made to the commercial aspects of a full scale implementation of sonic injection in all three converters in the smelter. INTRODUCTION AND OBJECTIVESAlthough the centennial of the Peirce-Smith (PS) converting process has recently been celebrated (Peirce and Smith, 1909; Southwick, 2009), the technology has essentially not changed much since its inception. PS converting is used extensively in the Cu, Ni and PGM industry to remove iron and sulphur from a molten matte phase. A typical PS converting process would use low pressure air supplied by a blower to bubble air through the molten bath. This bubbling injection regime is inherently inefficient from a process and energy consideration."

Jan 1, 2012