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By H. Blaha, H. Wagner

"Room and pillar workings in salt mines are preferred sites for underground waste disposal. A critical issue in selecting waste disposal sites is long-term behaviour of such workings. The long-term behaviour of salt pillars is controlled by the pillar geometry, i.e. the height, width and length of pillars and the level of pillar stress. The latter has a strong influence on creep characteristics of salt pillars whereas the width to height ratio of salt pillars determines the strength of pillars and the deformation characteristics of salt pillars.Three different regimes of pillar creep behaviour of salt pillars can be distinguished, namely a stress level below which the rate of creep approaches a value of zero, a stress range where the rate of creep is constant and finally a stress level above which the rate of creep accelerates. Long-term stability of room and pillar workings can be assured only when the pillar stress level falls within the first stress regime. Strength and creep tests on model salt pillars have shown that at stress levels below 40% of pillar strength the rate of creep approaches a value of zero, between stress levels of 40% and 65% the rate of creep is constant but increases with stress level. Above pillar stress levels of 65% the rate of creep accelerates.Long-term measurements of pillar deformation and surface subsidence above relatively shallow room and pillar workings in salt mines have confirmed these observations. Long-term strength of salt was found that be between 60% and 65% of short term strength. The evaluation of salt pillar behaviour on the basis of critical pillar stress levels was found to be superior to the traditional factor of safety concept because it allows relating pillar deformation measurements to actual pillar conditions. The approach described in the paper was used successfully to evaluate the stability of room and pillar workings in a salt mine and to design strategies to stabilise critical pillar workings."

Jan 1, 2015

By C. Harold Riches

This article is directed co a commentary on the patent system in its relation to the public interest. As man gained supremacy over his environment, he could devote progressively increasing portions o his time to improving his standards of living. In the history of the human race, we have advanced from the hollowed floating log to the modern steamship of the present age; from the sickle and flail to the reaper and combine; from the trumpet and drum as a means of communication co the telegraph, telephone, and radio; from the horse and ox cart to the automobile, truck, aeroplane, and train; and so on ad infinitum through the list of inventions on which are based the industrial and political economies and standards of living we enjoy today. It has also been a long road from the day of the alchemist and his closely guarded secrets to the era of the patent system and its storehouses of knowledge open to the world. The alchemist and the craft and merchant guilds closely guarded their secrets. In fact, they largely opposed innovations on the grounds that they might injure profits and restrict employment. In these days of unrest, with great clamour out of doors for radical changes in our political and industrial economies, it may not be untimely to examine one of the keystones which support the economic structure we know as the free enterprise system, the system which is predicated upon the right of the individual to own property. Many, through impractical idealism, ignorance, confused thinking, or blind political prejudice, advocate the substitution of ownership by the State ? for the right of ownership by the individual. As civilization has advanced to the high standards of living we enjoy today through the efforts of a comparatively few inventors, the patent system which has provided the incentive that created the inventions on which our industries and our employment are based is fully understood and appreciated by a comparatively small percentage of our people. As a result, the patent system, as a keystone in our free enterprise economy, is an apt target for destructive criticism, with the thought, possibly, that by eliminating or drastically restricting the several rights to individual ownership one by one, ownership by the State will progressively replace ownership by the individual.

Jan 1, 1949

By W. A. Jones

"The Ross mine, a subsidiary operation of Hollinger Consolidated Gold Mines, Limited, is near the north end of lot 1, con. II, Hislop tp., Ontario. The property comprises the north half of lot 1, con. II, and the south onethird of lot 1, con. III. It is readily reached by a good motor road from the village of Ramore, 7 1/2 miles to the southeast on the Ontario Northland railway. The mine is being developed to a depth of 1,500 feet, and the current daily production rate is approximately 300 tons. From the inception of operations in March 1935 until December 31, 1945, 692,000 tons of ore, with a total value of $5,762,685, was milled . The silver to gold ratio of 1.48 to 1 is unusually high for Ontario gold mines.TYPE OF 0REBODIES AND MINERALIZATIONThe orebodies consist of lens-shaped and pipe-like stringer lodes and tabular vein zones composed of parallel quartz stringers. The host rocks are steeply inclined eruptive breccias and tuffs, striking N.70°W., intruded by very small stocks of red syenite. The orebodies appear to be spatially related to an intricate system of fault planes. Hydrothermal alteration is widespread and is not zonally related to individual quartz stringers. The wall-rocks contain abundant fine-grained pyrite, but gold is confined to the quartz stringers.RELATIONSHIP TO REGIONAL STRUCTURELack of outcrops has prevented the detailed mapping of the Keewatin complex in the vicinity of the Ross mine with the degree of success that has been achieved in the Porcupine area.A northwesterly trending belt of slates and greywackes, bounded by faults, forms the central part of a broad anticlinal arch about 3 1/2 miles north of the Ross shaft. Lava flows forming the south flank of the structure face south toward the mine. If the sediments are to be tentatively correlated with the large areas of Keewatin slates and greywackes of the Porcupine area, it must be assumed that they are younger than the lava flows and that they have been down-faulted."

Jan 1, 1954

By D. Sharma, A. K. Singh, R. Singh, P. K. Mandal, M. Sarkar

"This paper deals with the stability investigations carried out at the XIVth seam of Jitpur colliery. The study was conducted to investigate the possible causes of roof cavity formation and face spalling at the middle slice face of block-3 longwall panel and to suggest remedial measures. The instrumentation and monitoring work was carried out in the panel over a period of nine months. On the basis of observations, it was found that if the maximum face span was reduced from the existing 4.8 m to 3.6 m, and if the face time schedule cycle was reduced from a maximum of 37 days to about 18 days, this problem could be eliminated. The recommendations of CMRI have been implemented in the middle slice face of block-4 panel with success. IntroductionModerate to steeply dipping, undisturbed seams of uniform thickness are worked by way of inclined slicing parallel to walls. In this method, the seams are treated as a combination of several moderately thick seams dipping parallel to roof and floor. Numerous variations of multislice mining have been used worldwide to get high coal recovery under local conditions of geology, subsidence control, proness to spontaneous combustion, statutes and economics. Multislice mining can proceed either downward descending from the roof or upward ascending from the floor. Ascending methods require backfill behind the working face to provide a base for the next slice. It is also adopted for surface protection against subsidence or mining under a massive roof. This paper presents a scientific study conducted in Jitpur colliery, IISCO where a 9 m thick seam is mined in three slices in ascending order with stowing."

Jan 1, 2002

By G. G. Bowser

Introduction Flame shots are of very infrequent occurrence in the coal mines of Nova Scotia. Probably not more than one is recorded in three months. Many shot-firers have never experienced one, and many never will. As a consequence, although all such occurrences are very carefully investigated, information concerning the cause of flame shots is somewhat meagre. In the course of the years, however, something has been learned of the practices and conditions that are responsible for them. During the past ten? years, over seventeen million shots were fired in the coal mines of Nova Scotia and only fifty-two faulty shots were reported or investigated during that time. In thirty-nine of these, flames were reported; in five, sparks only; and in eight, smoke only. In eight of these occurrences, unburned explosive was found after firing. In one of these eight, flame was seen in the back part of the hole, and an accompanying hissing sound pointed to burning explosive. In four of them, there was no evidence that gas was not ignited. All samples of explosives from these faulty shots which were submitted for analysis were found to be normal, except two, in 1937, which contained excessive moisture. These two samples were from two following shots in the same room on the same day. The initial cause of trouble with all eight shots was one or several of the following: explosives in poor condition, separation of cartridges, incorrect priming, shot hole in poor condition or not properly cleaned. In the case of sixteen or seventeen of the thirty-nine shots which flamed, data are insufficient for conclusions to be drawn as to the cause of the flame.

Jan 1, 1947

By L. G. Morrell

Introduction A Self-Dumping cage which combines the features of a small skip and a cage has been used in a vertical winze between the 2,000 and 2,500 levels at the Coniaurum mine for the past three years, during which time its success has been demonstrated by uninterrupted service and low maintenance charges. lt was designed by John Reddington, mine manager, and was built under his supervision in the Coniaurum mine shops. Being new in many of its operating features, a small-scale model was made and tried before the final construction was undertaken. The mechanical performance of the model suggested a few minor changes that were incorporated in the final drawings. During its three years of use, the automatic dumping device has saved the expense of deck-handling of the cars. This actually represents a gross economy of something over four times the cost of construction and installation, which totalled $1,325. The cage, empty, weighs 2,200 pounds, of which 500 pounds represents the weight of the dumping accessory and necessarily heavier construction. Besides a considerable financial saving, the time saved in unloading increases the daily hoisting capacity of the winze. In raising ore from the 2,500 level, five minutes are required for a complete trip. Allowing one minute for the alternative of decking, we believe that the automatic dumping has increased the capacity of the winze hoist nearly 20 percent.

Jan 1, 1933

By N. Saracoglu, J. P. Golightly, R. H. Wallis, J. J. Brummer

"The McClean uranium deposits are in northern Saskatchewan, 11 km west-northwest of the Rabbit Lake mine. Their average grade is 1.8% UJ0 8 and they contain 6,350 tonnes of uranium oxide in seven pods of variable grade and mineral assemblage. They are hosted by both basal Athabasca Group and the regolith developed on the underlying crystalline basement. The major mineral facies are: sulphide, arsenide, 'bleached', and hematite, with the important uranium minerals being coffinite, uraninite and pitchblende.Abundances of carbon and sulphur isotopes are consistent with their derivation from pyritic graphite in basement gneisses. Isotopes of oxygen and hydrogen suggest mineralizing fluids were aqueous and at temperatures of about 200°C. Ar39/ Ar40 laser age determination of illite indicates mineralization began about 1300 m.y, ago and that significant hydrothermal alteration ceased about 1170 m.y. ago though Pb/U data suggest the deposits continued to evolve into the Mesozoic.The deposits are interpreted as the result of oxidizing ground water stripping uranium and other metals from either the Athabasca sandstone, especially the heavy mineral layers, or from the regolith, and precipitating these when encountering a warm reduced fluid emanating from the basement."

Jan 1, 1984

By Guocheng Pan

"Although many factors play roles in the estimation of recoverable reserves, smoothing effect and conditional bias are considered major geostatistical issues in the estimation. This paper introduces measures for smoothing effect and conditional bias, and provides insights into their relation to the estimation of recoverable reserves. Both smoothing effect and conditional bias are intrinsic to the information effect and kriging estimators. For a given level of drilling information, however, it is possible to identify the optimal search radius that minimizes conditional bias. Furthermore, it is also feasible to define variance correction factor for reduction of the smoothing effect from exploration block models. Both of these components are key to the accurate estimation of recoverable reserves. IntroductionThe accurate estimation of recoverable reserves is critical to decision making in different phases of feasibility study and mine planning. Much attention for improving the methodology of estimation has been focussed on the effect of the change-of-support (Parker, 1980; Dagdelen, 1996). For example, it is essential to make a volume- variance correction to the estimate of multiple indicator kriging (Hoerger, 1992). When the size of block, b, in the geostatistical model differs from that of selective mining unit (SMU), v, a volume-variance correction is warranted for the prediction of recoverable reserves.Most mining plans and decisions are made prior to the availability of high density blast-hole samples. In most mining operations, the true SMU grade Zv is unknown at the time of selection. Instead, the selection is based on the estimate Z v**derived from high density blast-hole samples within the deposit G. Nevertheless, the estimate Z v * of recoverable reserves in the stage of mine planning is derived from exploration data. At the end, the production result must be reconciled to the estimate Z v * . In other words, the selection is based on Z v** from blast-hole samples, while the final production figures are reconciled to Z v * from exploration drilling. For a given preselected cutoff grade z0, the actual mining panels will consist of the units having the estimated grade Z v** =z0 rather than the true grade Zv =z0. The difference between Z v** and Zv is usually of less concern."

Jan 1, 1998

By Balmer Neilly

FOR some reason or other, Mine Taxation has never been a popular subject for discussion in meetings of this kind, and it has never received the study and consideration its importance demanded. By way of explanation, two reasons may be suggested. In the first place, the computation, adjustment, and final payment of taxes, have been looked upon in most cases as a Head Office chore. Secondly, since taxes represent an uncontrollable cost item, they have been treated as an added rather than an inclusive factor in calculating unit costs. Perhaps because I am half Irish, and therefore resent taxation of all kinds, perhaps because I am half Scotch, and am therefore concerned with the results, I have always taken a keen interest in this subject. Moreover, by some peculiar set of circumstances, I have been a participating party in many, perhaps I can say most, of the discussions on this subject that have taken place between the Governments and the representatives of this industry during the past thirty years. Looking backward, certain very definite impressions remain. Political considerations have never had any part in these discussions. Views have been exchanged upon the frankest possible basis, and, when we disagreed on some particular detail, we agreed to disagree, and followed through in harmony and? good faith. We, as an industry, have refrained from importuning and fault finding in ways that might be considered as petty or selfish, and it is only upon occasions such as this, where conditions necessitate action, that we lay our troubles before the powers that be. The Ontario Mining Tax Act was drafted by men who were earnest and practical as to purpose, and that Act has stood the test of time. It is, in. truth, a mode! Act, for it has been copied in its general clauses by both Quebec and the Dominion of Canada. We all know that, when a machine is running smoothly, we should leave it alone. The same is true of a well designed, easily applicable, taxation measure, and our present difficulty with respect to this Act arises out of an amendment made in 1916. In that year, you will remember, the Dominion imposed a wartime Income Tax Act. It was described as a wartime necessity and it was intimated t:1 at with the end of hostilities its application would be restricted and finally cancelled. The rate of taxation was modest, and when the Ontario Government was asked that the Dominion Income Tax be allowed as a deductible item, they readily acquiesced. This was looked upon as a temporary arrangement.

Jan 1, 1943

By Matthew Janes

Advantages: Clean samples Low sample disturbance Very low spoil Versatile Fast Penetrates all formations Resonant Drill 100 or 150 kW Self tuning to resonance Rotation to 100 rpm Increased depth in dense soil Increased productivity Reduce water use Reduce casing plugging

May 1, 2013

By Royston Colbourne

Objectives Of Presentation - Identify specific risks - A fresh look at risk - Provide a moment reflection on risk - Open discussion on risk A route to solution and advanced thinking.

May 1, 2010

By D. L. Griffith

THE realization by metallurgists of the important effect that traces of impurity may have upon the properties of a metal, and their steady demand for purer and still purer metals, have made the special cools for 'trace' analysis of increasing value. In the United States at least, spectrographic analysis is becoming the standard method for determining the impurities in zinc die-casting alloys. The Hudson Bay Mining and Smelting Company, as a producer of virtually pure zinc, uses the spectrograph to control the purity of its products, and-as the electrolytic method is employed here-to control both the impurities in the electrolyte and those 'trace' elements, which, while they do not contaminate the zinc, have a great effect on the plating efficiency. The general plan of the laboratory is shown in Figure l; the housing for air purification, which is on the roof, is indicated by broken lines. One of the chief factors affecting the layout was the easy way in which a spectrographic assay can be spoiled by contamination. To minimize the quantity of dust tracked in, the laboratory was made separate from the general research laboratories, and an office was placed between the two. This arrangement has its drawback because of the traffic through the office, but it has effectively cut down dust. For similar reasons, the available space was subdivided into a number of small rooms, and the air currents in the laboratory were so arranged that dust would be carried where it would do least harm. Air is drawn in at the roof over a 50-kilowatt bank of Calrod heaters, through Annis air filters, by a No. 4 Sirocco fan. Most of it is forced into the spectrograph room, but some goes to the office and darkroom. The air flow is from the spectrograph room, through the plate-measuring room, into the chemical laboratory, where it is exhausted by a No. 1% Sirocco fan on the fume hood. Air can also re-circulate from the plate-measuring room back to the heater. The arrangement is such that the air in the laboratory is maintained at higher pressure than the outside air; consequently, no dirt enters through cracks about the windows and doors. A thermo-regulator holds the temperature constant within one or two degrees; only on the hottest days in summer does the temperature rise enough to affect the focus of the instrument.

Jan 1, 1940

By R. Loj

Katowice Coal Holding (KHW) is one of the largest coal companies in Europe. The company owns five coal mines with a daily output of around 60 000 tons of coal. In the Katowice city area, very good quality steam coal is extracted. The depth of mining varies between 400 and 1100 m and some of the mines rank amongst those most afflicted by methane in the Upper Silesian Coal Basin, with the methane hazard having a significant impact on production and safety. ?Myslowice-Wesola? mine, being a part of the Katowice Coal Holding is characterized by high methane and rockburst hazards. The mine is equipped with a modern surface drainage pumping station. At the mentioned mine, longwall 514 was selected for analysis of its methane emission. The longwall was extracting the thick seam 501 (over 4 m), at a depth of over 900 m, which was subject to high stress and high gas concentration conditions. At a distance of about 50 m above, seam 501 is covered by thin seam 416. The strata between these two seams are sandstone and mudstone layers. In the floor of seam 501, with a thin shale interlayer, is located seam 510, which is the thickest (over 10m) and richest coal seam in the Upper Silesian Coal Basin. In longwall 514 and it?s vicinity, methane was the dominant risk. For this longwall three methods of classical gas drainage were carried out. At first, drainage was undertaken using long boreholes from a cross-cut at level 665 m, located far from the production panel. Later, it was performed using typical boreholes drilled from the ventilation gallery (tail gate road). Finally, it was undertaken using a degassing drift executed in the upper coal seam 416. All of these headings, ie. cross-cut level 665 m, the ventilation road and conveyor road in seam 501 and the degassing drift in seam 416, were equipped with media for drilling and proper drainage pipelines. Due to the high rockburst hazard and some problems with caving, several kinds of de-stressing and torpedo blasts were carried out in both coal seams and roof rocks. The subsequent analysis and experiments allowed the establishment of some general rules for carrying out degassing operations effectively. The effectiveness of a degassing drift was demonstrated. In some instances, the system allowed more than 70% of the total methane released to be captured and fed into pipelines. The aforementioned blasts had a marginal impact on methane emissions and the efficiency of degassing methods. Cyclic drilling and regular switching of boreholes in phase with the mining progress and working face advance were shown to be essential.

Aug 1, 2013

By G. W. R. Kuzyk

"Hydraulic drills, recently implemented at the Tantalum Mining Corporation of Canada, Limited, Bernie Lake Mine, are proving to be an economic alternative to pneumatic drilling systems. The paper describes the application of an electric-hydraulic drill jumbo to the mechanized room-and-pillar mine and its performance. The application of these drills resulted in improved environmental and working conditions.Drill rods and bits are a major cost centre in hard-rock mining applications. The paper also discusses the performance of one manufacturer's product used on the hydraulic drills.IntroductionThe Tantalum Mining Corporation of Canada, Limited (TANCO) started producing tantalum ore from its Bernie Lake pegmatite in 1969. The pegmatite, encased in amphibolite, is shallow seated and flat lying. It is defined by diamond drilling along 4,000 feet of strike and 1,500 feet down dip, ranging in thickness from 60 to 280 feet. Relatively well defined zones of mineralization occur within the pegmatite and form separate orebodies of tantalum, lithium and cesium."

Jan 1, 1981

By Robert E. Wood

Engineers have known for some time that the efficiency of filtering iron ore concentrate slurry can be significantly improved by pre-heating the slurry ahead of the filters. However, heating such large quantities of dense slurry by conventional means has proven to be inefficient and high-maintenance. Recently though, submerged combustion was considered by Altos Hornos de Mexico SA (AHMSA), an integrated steel producer in the state of Coahuila, Mexico, as a means of pre-heating their iron ore concentrate. The company toured many iron ore facilities in Brasil and Labrador, reviewing their heating processes, and concluded that submerged combustion could provide a competitive advantage through operational efficiency and lower capital cost than steam boilers. Inproheat was retained by the company to design and manufacture a SubCom slurry heating system to heat 403 m3/h of iron ore concentrate slurry from 25°C to 60°C. The 60GJ/h SubCom system consists of five natural gas combustion chambers mounted in an iron ore concentrate storage tank. The system features a heat recovery unit whereby the exhaust gases are used to preheat the incoming slurry stream, giving the system an overall thermal efficiency of 95%. As a result, the steel company expects to realise significant improvements in filtering efficiency which will enable them to increase the capacity of their pelletising plant without installing additional filters.

May 1, 2010

By Andre L. Du Preez

Global mine hoisting regulations require safety fall arrest systems to be installed on vertical conveyance systems capable of safely decelerating and supporting a fully loaded conveyance in the event of a rope severance. Most current arresting systems are incapable of producing controlled safe deceleration rates. Although safety ?dogs? achieve marginally acceptable results on wooden guides, difficulties arise in achieving safe deceleration performance requirement where safety arrest systems operate on steel shaft guides. Previously, arresting systems capable of operating with steel guides have been incapable of producing controlled deceleration rates during the arresting of free-falling conveyances. Most are ?instanton? systems, whereby an occupant inside a conveyance being arrested would be subjected to unacceptably high deceleration forces. This paper briefly highlights the background to the selection process of Rio Tinto?s Technical Staff of a suitable Mine Conveyance Safety Fall Arrest System for #1 Shaft at Rio Tinto Oyu Tolgoi Mine, Mongolia. It also describes the Drop Test and Free Fall Test procedure and the results leading to the acceptance of the Horne Group Levelok® Emergency Braking Technology for the Oyu Tolgoi #1 Shaft in Mongolia. The paper highlights Rio Tinto?s primary objective for the selection of this advanced technology on their primary production shaft cage system as an emergency safety catch braking system combined as an advance hydraulic chairing system. It describes the design and operational parameters and the 'Fail to Safe' interfacing with current automated mine hoist systems.

Aug 1, 2013

By L. A. Melis, A. R. Marchbank, S. A. Webster

"Certain northern Saskatchewan uranium ores have a high content of nickel and cobalt which offer the potential for recovery as a by-product to uranium. A nickel/cobalt recovery process has been developed as a viable method of recovering a marketable concentrate from typical uranium raffinate solution.Impurities are first removed from the raffinate and the pure solution is then treated with sodium carbonate to recover a bulk nickel/cobalt carbonate precipitate for sale to a primary nickel producer. All contaminants of concern are removed to very low levels and the product is free of radioactive contamination with gamma emissions significantly below natural background. Cost estimates have shown that installation of a nickel/cobalt recovery circuit within a uranium process plant is economically feasible.The testwork that led up to the selected process is described along with recommendations for further investigations such as additional testing of hydroxide precipitation as a possible viable alternative to carbonate. The selected process is described and project economics are briefly reviewed.PROCESS TEST PROGRAMBackgroundExtensive metallurgical research has been performed over the years to develop a process for recovering uranium from the Midwest deposit in northern Saskatchewan. During the course of this research, a certain amount of information became available which suggested that recovery of nickel and cobalt from uranium raffinate could be economically feasible. It was decided to undertake a test program which would investigate methods of separating nickel and cobalt from radioactive and other metal contamination to permit production of a saleable product.Available technology suggested that three general approaches could be taken to recover nickel and cobalt. The first and simplest approach would be to selectively precipitate the impurities of concern, primarily arsenic, iron and radium, and then recover a bulk concentrate from the purified raffinate. The second approach would be to purify the raffinate and then remove cobalt from solution by solvent extraction producing pure nickel and cobalt solutions for further treatment. The third approach would be to precipitate all metals from solution and then selectively re-dissolve nickel and cobalt in ammoniac solution which would be further treated by solvent extraction for nickel recovery, leaving cobalt for further treatment."

Jan 1, 1993

By E. Busse, J. E. Burgener, J. G. Eacott, M. C. Robinson, P. E. Burgener

"This paper presents a preliminary assessment of the technical and economic feasibility of a caustic leach - electrowinning process for the recovery of zinc and lead from electric arc furnace baghouse dust at a mini-steelplant. Recent studies and literature are referenced briefly as they pertain to the formation and characterization of dust, toxicity considerations and alternative dust treatment and disposal options.Laboratory testwork results, published data, pilot plant experience and anticipated influences resulting from recycling residues are used for the purpose of developing a conceptual design for a caustic leach - electrowinning plant to treat 15,000 tonnes/year of dust at a one million tonnes /year capacity steelplant in Canada.Target economic studies, comprising preliminary estimates of capital and operating costs, revenues and rate of return are presented. Economic and commercial considerations concerning the relative merits of dust treatment at a centralized facility compared with an on-site plant are discussed.IntroductionThe treatment or disposal of mini-steelplant electric arc furnace (EAF) baghouse dust has been given increasing attention in recent years for two principal reasons. Firstly, the dust is now classed as a hazardous waste material under V.S. EPA regulations which prohibit its disposal in dumps other than controlled landfill sites. Secondly, the dust contains certain metal values, notably zinc and lead, which may be economically recoverable, depending on the costs associated with disposal resulting from enforcement of the EPA regulations. Other metallurgical dusts and waste materials, from both ferrous and non-ferrous operations, may require the same considerations as EAF baghouse dust.Several studies have been carried out to examine various aspects of dust treatment but few commercial plants are in operation. Technology employed uses pyrometallurgical techniques. Commercial-scale hydrometallurgical plants are not known to exist although small-scale plants are frequently more economically attractive than their pyrometallurgical counterparts which generally require economies of scale to be viable.The concentration of mini-steelplants in northeast V.S.A. and southeast Canada merits study to determine whether or not dust treatment for metals recovery is a commercially feasible alternative to disposal.This paper examines the technical and economic feasibility of a caustic leach - electrowinning process for the recovery of zinc and lead from EAF baghouse dust at an on-site ministeel plant processing carbon steel scrap and discusses economic and commercial considerations pertaining to dust treatment at a larger, centralized facility."

Jan 1, 1984

"Nanisivik Mines Ltd. operates a 10-M W diesel-electric generating plant at its zinc-lead operation on Baffin Island in the Canadian Arctic. This paper provides a description of the plant and the integrated waste heat recovery system. Data is presented detailing the actual costs of operating a plant over a period of seven years. Problems in operation are described as well as the success of the plant in meeting its objectives over the years. IntroductionNanisivik is located on the shore of Strathcona Sound at the north end of Baffin Island (Fig. I). Nanisivik Mines Ltd. has operated a 2,100 tonne per day zinc-lead underground mine and a concentrator, together with supporting infrastructure, at this location since October 1976. Annual production of 100 000 tonnes of zinc and 10 000 tonnes of lead concentrate is transported by ship to Europe during the mid -July to mid October shipping season.All electrical needs of the project are provided by the company-owned and -operated power plant. Facilities served by this electrical system are the underground mining areas, the concentrator and industrial area, a townsite, airport, and shiploading dock complex."

Jan 1, 1986

By Trevor McGiddy

"Australia's prosperity relies significantly on income generated from exports of resources and agricultural products. In 1989-1990, coal was Australia's most valuable export commodity, contributing. A $5.7 billion or 14% of all export income.The abundance and quality of its coal resources and the proximity of Australia to the rapidly developing economies of Southeast Asia were significant factors that encouraged export-oriented growth and investment and will continue to do so. On the other hand, the 1980shighlighted the sensitivity of the industry to international changes in supply and demand, currency and socio-political forces.Following many years of disappointing returns for investors, mainly as a result of falling Australian dollar coal prices, resolve will be necessary to maintain competitiveness with resource-rich nations. In recent years, operators, unions and governments have begun to embark on a long overdue rationalization of domestic issues in a bid to increase productivity and reduce costs.The nature of mining operations is also changing; deeper surface mines and the growth of longwall mining will require the development of new technology and skills. Other challenges emerging from the international environmental debate will require that Australia responds appropriately to demands for cleaner fuels, energy efficiency and environmental responsibility.The future development of the Australian coal industry will therefore be influenced by its own ability to become more efficient and mature in the production of quality coal products and through rational international response to environmental questions."

Jan 1, 1992