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By E. Swartzman

"IntroductionGENERALLY, the necessity for mining coals of higher impurity content, the drive for lower costs by intensive mine mechanization, changing market requirements, and the increasing competition of oil and natural gas, have continued to result in an upward rise in coal preparation, and have necessitated a more intensive study of coal preparation problems.Increasing adoption of •continuous mining equipment, for example, is introducing new problems in coal preparation. Limited experimental work in the United States (1) shows that the effect of the continuous miner on size distribution varies with the characteristics of the seam. In some seams, the fines problem is lessened, in others it is greatly aggravated. Generally there is a decrease in the relative amount of the top sizes (plus 2 in.) and a substantial increase in the intermediate sizes (down to about 1/8 in.). Contrary to expected results•, where continuous miners with vertical-moving cutting heads are used, an increase in impurities in the slack sizes does not necessarily occur where draw-slate is taken. This is because the draw-slate tends to be kicked out in lump form. However, if a seam contains bands •and lenses of impurities they are bound to be in the mined product."

Jan 1, 1952

"The Val d'Or Division now comprises the Lucien C. Beliveau Mine and Concentrator (formerly the Pascalis, described below) and the Chimo Mine. Cambior acquired an initial 50% interest in the Chimo Mine in May 1989 and the remaining 50% in April 1990. Cambior's share of 1989 production was 2121 ounces; the company expects to net 23 750 ounces from Chimo in 1990. Pascalis MineUPDATERenamed the Lucien C. Beliveau Mine at its official inauguration in September 1989, the mine is exceeding forecasts, producing over 11 500 ounces of gold in the first half of 1990. Cambior expects 1990 production to total 34 000 ounces.IntroductionThe Pascalis Mine is located 16 miles east o f Val d'Or, Quebec, and is accessible by a three mile gravel road off highway 117 (Fig. I).The property is wholly owned by Cambior.The Pascalis gold deposit consists o f a sub-vertical diorite dyke 1000 ft long by 30 ft wide containing quartz and tourmaline veins with inclusions of pyrite and native gold . Three vein systems ca n be seen in the deposit , the most important being tensile veins oriented at a right angle to the direction of the dyke and inclined at 40 degrees. These overlapping veins vary in thickness from 4 in. to 40 in. and occur at intervals of six to ten ft. The deposit is, therefore, very difficult to evaluate; a complete evaluation would require drifts over the whole width of the dyke combined with relatively short drill holes (Fig . 2)."

Jan 1, 1990

By G. Langlands

"R. Tenbergen Is this flotation machine suitable in the flotation ofInco ball mill discharges where we have a coarse feed at 60% solids?Reply Experience has shown that there is not a significant increase in the wear life of these machines when handling coarse material (8 mesh) at 60% solids. A common practice in Europe is shut down on the week-ends.The material is allowed to settle and on start-up an injectic of air for 15 seconds is sufficient prior to start-up. At,mining we put our unit in the middle of a bank of 44 cells and in order to ensure severe sanding we shut the aker cell down while the remaining cells kept running. After 20-25 seconds of air the cell started without trouble.P. Mahant Is there a build-up inside the impellor shaft housing? Falconbrige Ltd.Reply There is no sand build-up but rather a scale build-up which due to a flexing action frees itself periodically. Part of the design of the machine permits a water injection into the shaft housing to free any build-up. This is done in Europe during the week-end shut down."

Jan 1, 1984

By B. Voyzelle

The deterioration of highway and bridge infrastructure has received considerable attention in recent years because of the billions of dollars needed for repair and rehabilitation. A major factor contributing to this problem is the corrosion of steel reinforcement. Reinforcing steels with good corrosion resistance and relatively low price are therefore essential for maintenance, cost reduction and service-life extension of the steel-reinforced structures. This article describes the development of low-alloying steels that offers good corrosion resistance with reasonably low cost. Topics include steel microstructures, mechanical properties, corrosion performance, industrial applications and economic aspects.

Jan 1, 2005

By M. Djivre, T. Eger, A. Godwin, I. Bhattacherya

Load-haul-dump vehicles (LHDs) are extensively used in underground mining, however, equipment design and operating conditions contribute to restricted operator sight lines. The inability to clearly see people, objects, or hazards around the machine has contributed to a number of accidents including fatal injuries. In order to identify vehicle design characteristics resulting in restricted and blocked sightlines, line-of-sight assessments are traditionally completed in the field. However, field methods are unable to evaluate lineof- sight under dynamic operating conditions, and are limited in their ability to provide feedback on the impact of various operator characteristics such as sitting height. Results of this research show computer simulation and virtual reality can be successfully used to evaluate line-of-sight during the operation of LHD vehicles. In order to benefit from virtual reality applications, the work environment, LHD vehicle, and human posture need to be represented as accurately as possible. A computer simulation program with ergonomic analysis features, Classic JACK 3.1, was successfully used. Threedimensional CAD models of LHDs were developed from manufacturer specifications and pictures taken from LHDs currently in use. The LHD models were imported into the JACK environment, a digital human was positioned in the cab of the LHD vehicle, and the vehicle and human were driven over a typical mine route. Real-time feedback in the JACK program was used to identify what the operator could see under different operating conditions. Machine characteristics and operating scenarios resulting in impaired line-of-sight were successfully identified with this method. The JACK program could also provide real-time feedback on the human’s joint forces and torques, strength requirements, postural comfort, and metabolic energy expenditure. As a result, this method could be used to successfully evaluate musculoskeletal injury risk factors along with system design recommendations to improve workplace safety and productivity in any setting. The LHDs evaluated in the JACK software package can also be combined with mine models and imported into other VR software packages (e.g. Blender) in order to enable viewing in Laurentian University’s Virtual Reality Laboratory. The VR models using these packages can be viewed in stereo to provide better appreciation of spatial vision issues.

Jan 1, 2005

By Fred Horne

1N THIS PAPER, the writer proposes to limit his comments to few generalized phases of the subject, based on his personal experience in the midwestern United 'States and in one section .of the Coal Branch in Western Alberta. The following statistics are submitted to show the importance that strip mining has assumed in the coal mining industry of the United States. In 1914, 1,281,000 tons of strip coal were produced, amounting to 0.3 per cent of the total production. In 1948, the total was 13~,505,000 tons, representing 23.3 per cent. In 1949, the percentage figure dropped slightly and this can be partially accounted for by the labour disturbances prevalent throughout the year. In 1914, there were 48 power shovels and draglines being used in the stripping of coal; in 1949 there were 3,712, not to mention other types of coal stripping equipment such as bulldozers, tractors and scrapers, rotary excavators, and stackers. At the bituminous coal mines in Western Canada, strip mining was introduced only a few years ago, two of the major reasons for its development being the need for increased production during the war and post-war years and the need to hold the line on increasing production costs, but even in these few years the percentage of strip production has in-creased to such an extent that some mines that, five or six years ago, were producing all their tonnage from underground operations are today obtaining up to 80 per cent of their total output from strip mines.

Jan 1, 1951

By A-A. Bogno, M. Rappaz, J. Valloton, H. Henein

"Rapid solidification of Al-Cu droplets of eutectic composition was carried out using Impulse Atomization in an argon atmosphere, to study the microstructures forming at different cooling rates and undercoolings. Two distinct morphologies were observed within the investigated Al-33wt%Cu droplets microstructures: (i) A regular lamellar morphology and (ii) an undulated morphology. The volume fraction of each type of morphology was measured as a function of the droplet size and the nucleation undercooling was deduced using the hypercooling limit equation. The scale of the microstructures was determined through measurements of inter-lamellar spacing across and along the growth direction. Growth velocity and undercooling were deduced using Jackson and Hunt (1966) eutectic growth theory. Finally, mechanical properties were estimated through micro-hardness analysis using a Vickers hardness tester, revealing exceptional properties for an aluminum-copper alloy. Indeed, the hardness values, increasing with growth rate and undercooling, were 3 times higher than the values obtained in hypo-eutectic Al-Cu alloys.INTRODUCTION Eutectic alloys are very attractive due to their good fluidity allowing ready shaping of parts in casting processes as well as in thermal spray deposition. In addition, they yield microstructures with high mechanical properties, by the virtue of their scale/size which is defined by the solidification parameters and the thermodynamic and thermophysical properties of the given alloy. Therefore, it is important to understand the relationship between the microstructures and the solidification parameters of eutectic alloys in order to control their solidification path and mechanical properties. The latter could be improved by either adding an appropriate strengthening component to a base eutectic material (Böyük, MaraslI, Kaya, ÇadIrlI, & Keslioglu, 2009) or by refining the microstructures for more effective dislocation pinning (Campbell & Campbell, 2003). Tailoring the microstructure can also be beneficial to chemical (Freitas, Osório, Spinelli, & Garcia, 2014; Osório, Freire, Caram, & Garcia, 2012) or electrical (Kaya, 2012) properties of the material. Eutectic-type microstructures, usually formed from liquid (eutectic transformation) or solid (eutectoid transformation), are made up of two or more different phases, generally of lamellar or fibrous (rod like) morphologies (Kurz & Fisher, 1998). In general, a binary eutectic structure can be regular (when both phases are non-faceted) or irregular (one of the two phases is faceted), the two solid phases having roughly the composition of the liquid from which they are formed."

Jan 1, 2017

By L. E. Reed, I. G. L. Sinclair

An exploration program seeking kimberlite pipes, the common primary hosts for diamonds, Was' conducted during the years 1979 through 1982 in the James Bay Lowlands of Ontario by Selco Mining Corporation (now the Mining Division of BP Resources Canada) and Esso Minerals Canada. The area to be explored was selected on the basis of its regional geological setting, and because of the known presence of kimberlite indicator minerals in the region. The primary exploration technique was low level airborne magnetic surveying, followed by detailed ground geophysics. This work located many pipe-like bodies, with diameters of a few hundred metres, as well as several dykes. Targets located by these geophysical methods were drilled, intersecting a total of45 intrusions, consisting of34 alkaline diatremes containing tuffisitic breccias, 7 carbonatites, and 4 massive alnoites. K-Ar determinations indicated ages of 152 Ma and 180 Ma for two of the massive alnoites. The texture and general mineralogy of the tuffisitic breccias are similar to those of diatreme facies kimberlites, but detailed examination of their mineralogy and chemistry demonstrated that they lie within the alnoitic rather than the kimberlitic compositional field. Although the exploration program did not lead to the discovery of true kimberlites, it did demonstrate the presence of a large, previously unknown province of alkaline volcanic activity, which has no surface expression.

Jan 1, 1991

By D. Shishin

Continuous integrated experimental and thermodynamic modelling work is conducted in Pyrometallurgy Innovation Center (PYROSEARCH). The target is to develop a tool, which is capable to predict the compositions of phases, phase equilibria and enthalpy balance for pyrometallugical processes with higher accuracy. All these can be achieved by thermodynamic calculations based on Gibbs energy minimization algorithm. Recent developments made it possible to predict important factors, such as the chemical solubility of Cu in slag as a function of matte grade, temperature, P(SO2), Fe/SiO2 ratio in slag, wt% Al2O3, CaO and MgO in slag. In industrial practice, it is not only chemical solubility, but the overall amount of slag, which affects the recovery of copper and other valuable metals. It will also impact the energy balance. The presence of solids in the slag matrix influences the physical entrainment of matte in slag. Oxygen enrichment which is sometimes used to control the temperature of the furnace, may also affect the volatilization of minor elements into the gas phase. Same is true if additional fuel is used to compensate for heat balance. In other words, all key process parameters mentioned above are interrelated. Present study demonstrates the ways thermodynamic modelling can be used to link those process parameters on the example of copper smelting. INTRODUCTION Research methodology involving integrated thermodynamic modelling and experimental approach has been recently reported by the authors (Shishin, Hayes, & Jak, 2018 Shishin, Hidayat, Jak, Decterov, & Belov, 2016). Present paper reviews the updates and discusses challenges in the development of a large self- consistent thermodynamic database. The database covers the Al-Ca-Cu-Fe-Mg-O-Pb-S-Si-Zn-(Ag, As, Au, Bi, Ni, Sb, Sn) chemical system. The database works in the environment of FactSage software Bale et al., 2016 and related family of products: ChemApp (Petersen & Hack, 2007), ChemSheet and SimuSage. A list of phases, and thermodynamic models is shown in Table 1. For the copper industry, most important phases are Gas, Slag, Spinel and Liquid matte/metal/speiss. Black-colored elements represent the base system, elements in green can be considered as slag modifiers (slagging elements), and elements in red are minor. Ni is highlighted because it was included recently, in 2019, and currently under development. In addition to copper, the database covers the conditions typical for lead and zinc pyrometallurgical extraction. It is developed in consistency with the experimental results for high concentrations of Pb and Zn. Examples of applications in the present study include the thermodynamic analysis of fluxing for an agitated copper reactor to show the effect of Fe/SiO2, and calculations of copper slag cleaning using reductant.

Jan 1, 2019

By A. Roy, T. LeBel, P. Coursol, P. Lind

At the early stage of a mining project, small amounts of concentrates are available for testwork. For gold concentrate or ores containing significant arsenic levels, batch bench scale roasting is often unreliable, leading to highly variable gold recoveries to be used in the project’s financial justifications. With an appropriate bench scale unit using continuous feeding and residence time control for solid and gas phases, reliable numbers can be obtained at small scale with only a few hundred grams per test condition. This paper describes the development of a pilot fluid bed roasting unit by Kingston Process Metallurgy Inc. (KPM) to perform representative trials on gold concentrates containing arsenopyrite, arsenian pyrite and carbonaceous components. Calcines produced under different conditions were characterised by chemical analysis and electron microprobe; the calcine microstructure obtained is described. The most important parameter affecting gold recovery is oxygen content in the roasting atmosphere, with the lowest controlled oxygen level giving the highest gold recoveries. Higher local temperatures in the bed may cause the formation of molten glassy phases which can also reduce the gold recoveries significantly. The impact of roasting conditions in the two inch fluid bed is compared with commercial results obtained in full scale operation.

Jan 1, 2014

By Richard E. Barrett

SOME YEARS AGO I was associated with a mining operation which, because of its isolated location, burned wood for heating purposes. Year after year the tractors and tucks hauled the cordwood in from the edge of the ever-growing clearing. Each year the cartage costs became greater. The degree to which transportation distances affect the economics of fuels obviously varies with many factors, but the main criterion is the amount of heat a unit weight of the fuel will produce. For in-stance, wood is limited in most cases to a haulage distance of a few miles. Coal can be shipped hundreds of miles, whereas petroleum and gas ?can be transported thousands of miles. The world is now on the brink of having a new fuel -uranium. It has the virtue of being so concentrated that transportation costs can, for all practical purposes, be disregarded.

Jan 1, 1958

By M. Medraj, M. A. Arafin, D. P. Turner, P. Bocher

In this study, the kinetics of isothermal solidification during TLP bonding of Inconel 625 and 718 superalloys with nickel based multi-component filler alloy BNi-2 have been studied through a combination of direct experimentation and mathematical modeling in order to determine the effect of process variables and, thus, to optimize the process. The predicted isothermal solidification completion times from the boron diffusion model and migrating solid/liquid interface model were in good agreement with the experimentally determined values and, they were found to be significantly less than those of other nickel superalloys with different nickel based filler alloys. Further, significant reduction of holding time was observed with increasing bonding temperature and with decreasing joint gap. No significant grain growth in the base metals has been observed in the temperature range being investigated (1325 - 1394K).

Jan 1, 2006

By R. D. Brown

"Concerns over possible additional involvement of governments in Canada's mining industry and its adverse effects on the industry 's growth were a frequent topic of conversation at the recent Annual General Meeting of the CIM.Still painfully fresh in the minds of industry leaders are the disastrous results of the federal/provincial scramble over resource revenues which followed the relatively high metal prices witnessed in 1973/1974. At current metal prices, it is not surprising, then, that a nagging fear persists that these governments may once again restructure tax and other rules to the detriment of the industry and the country.This month, Tax Notes recalls some of the progress which the industry and governments have made in 1979 in the taxation of the resource sector, and urges that higher metal prices be viewed in light of the costly exploration, development and production efforts which will be required for the industry to continue to play its important role in our economy.IntroductionAt the Annual General Meeting of The Canadian Institute of Mining and Metallurgy, held in April, 1980, it was abundantly clear that there is widespread concern in Canada's mining industry that this country's tax regime may once again be blasted by ill winds of change.A stable and more favourable tax climate, as well as higher metal prices and profits, made 1979 almost a golden year for Canadian mining. However, from the tax viewpoint at least, there are some spots on the silver lining as apprehensions grow that the well-heralded battle between federal and provincial governments over oil and gas may spread to the mining sector, with serious damage to the industry and its newfound federal-provincial cooperation."

Jan 1, 1980

By B. R. Neufeld, M. G. Heximer, S. J. Roach, W. G. Van Luven, D. G. Reynolds

"Teck Metals Ltd. operates an integrated zinc-lead complex at Trail, British Columbia, Canada. In the zinc plant, zinc concentrates are roasted to produce calcine, which is then processed in the leaching circuit for zinc recovery. Calcine is first dissolved at pH <2.0. This is followed by a precipitation stage using additional calcine that removes iron as a ferric hydroxide precipitate which is recycled to the lead operations. It is during this pH adjustment that impurities, notably arsenic, antimony and germanium, are co-precipitated with ferric hydroxide which is the primary removal phase for these elements. Recent processing conditions have resulted in lower iron inputs to the leaching circuit and this has resulted in insufficient co-precipitation of key impurities. This paper summarizes the influence of iron concentrations on impurity removal using laboratory and plant scale surveys, and emphasizes key specification limits for the primary iron removal circuit.INTRODUCTIONThe Sulphide Leach Plant (SLP) at Teck Metals Ltd., Trail Operations produces a zinc sulphate electrolyte from three different zinc bearing streams:1. Calcine, primarily containing zinc oxide, from the roasters2. Zinc electrolyte from the Oxide Leach Plant (OLP) is produced by leaching zinc oxide fume from the pyrometallurgical lead smelting operations3. Zinc slurry from the Zinc Pressure Leach (ZPL) autoclaveThe feed sources are blended and introduced to the iron removal process to precipitate iron in the form of a hydrolyzed iron precipitate which is recycled to the lead smelting operation. Along with iron, impurities, namely arsenic, antimony, germanium and silica, also co-precipitate; this process acts as the primary removal step for these elements. Following iron removal, the electrolyte is further processed in the zinc dust purification circuits. Cadmium and copper are removed in the cold stage circuit via zinc dust cementation, followed by cobalt cementation in the hot stage circuit."

Jan 1, 2016

By Sukumar Bandopadhyay, Arunapuram Sundararajan

"For the last three decades, the application of network planning has provided a basis for a formal and general approach to the discipline of project management. For fixed activity duration, a very simple algorithm commonly known as critical path method (CPM), gives the length of time required for the total project as well as indicates the activities which are vital to the completion of a project. Project Evaluation Review Techniques (PER T) on the other hand, generalize the above approach to recognize uncertainty in the activity durations by allowing them to be random variables. One of the misleading aspects of current "" PER T"" solution method is, however, the implication that there is a unique critical path. In general, any number of paths could be critical, depending on the particular realization of the random activity durations that actually occur. In this case, simulation can be utilized to estimate completion time of a project.In this paper, the concept of criticality indexing is discussed, and a simulation model application which defines the critical path based on the criticality indexing concept, to a longwall development - extraction network, is presented. The model also provides suitable scheduling of resources based on the resource constraints and smooth s out period-t o-period assignments. IntroductionThe successful management of large-scale projects require careful planning, scheduling , and coordinating numerous interrelated activities. To aid in these task s, formal procedures based on the networks and network techniques (variously called PERT or CPM) were developed. In its original form the completion time for individual activities of a project was assumed fixed and known in advance: this in turn led to the familiar algorithms for computing the critical path, earliest start time, slack, and so forth. The unreality of such an assumption is, of course , apparent in many contexts. Consequently, attempts were made to introduce probalistic activity completion times, allowing representation of the stochastic nature of most projects."

Jan 1, 1987

By S. Kivrak

The firms in construction industry could not sufficiently adapt the rapidly emerging information technologies in recent years into their corporate structures. Therefore, in an effort to further exploit the benefits of information technology (IT), integration of the experiences and backgrounds of construction industry and the advantages of IT, is one of the most open-ended fields for improvement in this industry. Utilization of IT in the construction sites will positively affect the efficiency, productivity, quality and health & safety issues in the construction sites thus the cost and completion time of the projects. Within this context, augmented reality technology, which brings a new perspective into IT, can be put into the service of construction industry. Augmented reality which has been designed to improve the services in many application domains such as school education, military warfare, military trainings, industrial maintenance, retail and medical, can be defined in the simplest form as augmenting the real world with information from the virtual world. The main aim of this study, which presents an overview of an ongoing project, is to develop an innovative method by making a construction worker, foreman, equipment operator or a site engineer watch a very comprehensive and informative animation which will enable the said staff to perform or supervise all the phases of the activity he or she is in charge for in a more efficient, productive, safer and qualified manner by means of smart glasses using augmented reality systems. In this respect, training material related with the activities in the construction sites will be prepared and with a well-fictionalized scenario, animations exhibiting all the phases and details regarding the related activity (e.g. masonry, formwork and rebar works etc.), method of statement, correct and incorrect applications in comparison-wise manner, will be produced. Therefore, the user will be able to reach the training material, method statements etc. in the animations about the activity he or she is in charge for, enabling him or her to figure out the work as prescribed in the specifications. Basic trainings about the system will be given to target group, i.e. construction workers, foremen, operators, site engineers and managers working in the construction sites to apply the system on sites after all the system was tested. After the testings, to determine the effectiveness of this system, semi-structured interviews and survey questionnaires will be conducted among the mentioned target group. Therefore, the potential benefits of this system to the construction industry can be determined. The main target of this study is to implement an efficient, thorough construction management by orienting the staff in the construction sites to perform efficient, safe and qualified works by means of smart glasses that use augmented reality. There are relatively few studies about the implementations of augmented reality technology in construction. The outputs to be attained in the end of the study have the potential of improvement of time, cost, quality and safety parameters by ensuring a qualified, safe, efficient and productive construction management via augmented reality technology in the construction industry.

Aug 1, 2013

By S. Konetschnik, Lux Degel, R. Degel, T. Haslinger

UrbanGold and its partners from Mettop and SMS group have developed a novel technology for the recovery of valuables from all non-ferrous metals’ fractions of WEEE (Waste Electrical and Electronic Equipment), with a special focus on low qualities which are commonly landfilled or incinerated. The technology is marketed under the brand name “UrbanGold Flex” to illustrate the high flexibility in respect of plant design and raw material portfolio, allowing also the processing of low grade material and materials with high caloric values. The process of the technology’s centrepiece, a modified and enhanced bath smelting furnace called “HENRI”, was investigated in numerous pyrometallurgical trials as basis for a scale-up towards a capacity of up to 100,000 tons of WEEE-concentrates per year. All relevant facility components have been evaluated in respect of references, fall-back options, as well as exit strategies (alternatives) to minimize risks when establishing a novel technology. A spin-off within the development is the “UrbanGold Compact” technology which can be seen as optimization of state-of-the-art smelters by using an optimized TBRC as primary processing unit. As an UrbanGold Compact plant will be the first industrial scale reference of UrbanGold’s technologies, it is also explained in the publication. As precious metals recovery is of major (economical) importance when recycling WEEE, major attention has been given to minimize the losses of these valuables. These measures, as well as a sophisticated way of utilizing waste heat as far as possible, result in interesting business cases with gross profits of up to 20% or even more. INTRODUCTION Over the past years, the demand of electrical and electronic equipment has increased dramatically with technological progress. Innovations on the technology of electronic devices led to a shorter usage and lifespan and thus boosted the generation of Waste Electrical and Electronic Equipment (WEEE). WEEE is one of the fastest growing waste streams, growing at 3 to 4% per year worldwide and is expected to reach more than 52 million tons per year by 2021. Currently, about 45 Mt of these wastes are estimated to arise worldwide, and the trend is rising (Baldé et al., 2017).

Jan 1, 2019

By Anton Gronningsater

AT the present time we hear a great deal about organization of labour, collective bargaining, workmen&apos;s councils, and company unions; about C.1.0. with its principle of vertical unions and A.F.L., largely based on craft unions; and about provincial and federal laws for protection of labour&apos;s right to collective bargaining. What we perhaps hear too little about is corresponding organization of the employers, although it recently is mentioned more frequently. I will only mention W. H. Davis, Chairman of the United States War Labour Board, who has had and is having plenty of experience in this field and has also studied labour conditions in Europe-in Sweden for instance. He has repeatedly expressed the opinion that where employer-employee problems are involved, a thing badly needed in America is organization of employers as well as employees to get some order in the present chaos. With this I agree. I believe a strong organization on one side necessitates a correspondingly strong organization on the other side; that has at least been the experience in the industrialized countries in Europe. I happen to be fairly familiar with conditions in Norway, where they have struggled with these problems for fifty years, and a talk on the history, development, and present state of employer-employee relations in that country might perhaps be of interest as giving a general picture of the development of such relations in the northwestern European countries as a whole. The talk was originally given to the Fourth Year students in Mining and Metallurgy at the University of Toronto. I have changed it somewhat to fit a different audience, but I hope you will make allowances if you now and then are reminded of the school auditorium. I will try to be as objective and factual as possible, but it is probably unavoidable that some of what is said is coloured by personal opinion.

Jan 1, 1943

By G. K. Rutherford, G. W. Van Loon

"Tailings in the mining and smelting industry are reject products of the refining process which are deemed too deficient in native are to warrant smelting. They are essentially finely ground rock materials which have been moved by alluvial suspension from the site of crushing to a deposit site. It is realized that components of flotation chemicals used in specific gravity separation may become part of the tailings and also that sewage sludge or other materials may be added at some stage to the tailing deposits.It would seem, then, that as tailings have a similar parent material to soils, namely rocks, and that they have also been comminuted to similar size fractions, they would react in similar ways to soils. There is an increasing body of evidence and experience which both supports and negates this supposition. It is the object of this paper to point out similarities and contrasts between these two materials which may influence the vegetation and rehabilitation of tailings.Soil-Formlnq FactorsThere are considered to be six soil-forming factors which impart the particular and unique properties harboured by a soil at any site. It is .relevant to consider each of these in turn, as each provides an historically based parameter with which to judge tailing properties.Parent MaterialsAlthough all mineral soils have originally come from rocks, for most soils the route has been rather circuitous. Soils may be formed directly from underlying rocks, as in some parts of tropical and semitropical regions today; these are sedentary soils. However, most soils of the world have been formed by materials which were transported to their present site by ice, water or wind, or as volcanic ash. Virtually all soils in Canada have been transported by ice or water and deposited on an extraneous rock surface during the last glacial retreat. Ice-deposited materials are extraordinarily heterogeneous in their size components and may range from very bouldery and gravelly to predominantly clay-sized materials. Water deposited sediments are usually homogeneous, but nevertheless these also show considerable level variations. In many parts of Canada, clay-sized materials deposited in ephemeral post-glacial lakes form the parent material for soils."

Jan 1, 1982

By Neil Schofield

"The Pine Creek gold mineralization is associated with saddle reefs and quartz and quartz sulphide veining within the Enterprise Anticline. The anticlinal structure is complex and the mineralization was considered prior to development to be dominantly strata controlled. Gold grades vary up to 160 gin 1.5 m core samples with coefficients of variation in excess of three.The estimation of ore reserves for such a deposit must account for both the geological complexity and the extreme variability of gold grade.This paper describes the structural and variogram analysis of the gold grades and demonstrates the importance of incorporating the geological model in such an analysis. Variogram interpretation is greatly improved and greater insights into the finer geological structure areprovided. Part 2ofthis work presents the application of multigaussian kriging to reserve estimation for deposits with highly variable grade and which consequently demand highly selective mining operations. IntroductionThe Enterprise Gold Mine is situated some 220 km southeast of Darwin in Australia&apos;s tropical north. Gold is believed to have been discovered there in 1869 during the construction of the overland telegraph line.From 1894to 1915, some 75 000 ounces of gold were produced from 121 000 tonnes mined mainly by Chinese leaseholders. From 1906 to 1915, government-sponsored drilling led to the sinking of the Enterprise Shaft to 79 m and several drives were developed. Mining ceased because of war.Since late 1980, Goldfields Exploration Pty. Ltd. had explored on several mining tenements near Pine Creek under joint venture with the title holders, Enterprise Mines NL. This work culminated in the development of the current mine which opened on October 29, 1985.Feasibility studies to determine the economic viability of mining were based on ore reserves generated by project geologists using a sectional polygonal approach tuned to the interpreted geological control of the mineralization.The study motivating this two-part paper covers are-estimation of the recoverable reserve s using the geostatistical approach of multigaussian kriging developed at Stanford University, (Verly, 1984)."

Jan 1, 1988