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By FJ. Johnson

Polymer utilization has increased steadily over the past several decades; however, their usefulness is sometimes limited by natural forces. For example, polymers tend to degrade when subjected to elevated temperatures. This degradation can release toxic fumes, create excess smoke, and aid in the spread of fire. For these reasons, many polymers are filled with various compounds which impart flame retardancy (FR) properties. These fillers do not make polymers non-combustible; rather, they increase resistance to ignition and reduce bum rate. Also, they suppress smoke generation, which is important as up to 80% of fire-related deaths are due to smoke inhalation [1]. Therefore, methods to impart flame retardancy in polymers are industrially important. The early flame retardants used in polymers were halogen-based, working on the principle of inhibiting free radical formation in the vapour phase thus impeding combustion propagation [2]. Usually these were combined with antimony compounds such as Sb203 to decrease loading, yet provide the same FR qualities. However, questions have arisen recently concerning toxicity of halogenated flame retardants. Possible release of toxic compounds (such as dioxins) upon combustion has been reported [3]. Fear of future regulations concerning halogen addition has led to the search for different FR fillers. Two of the more common replacements for halogen-based systems are alumina trihydrate (Al(OH)3 or ATH), and magnesium hydroxide (Mg(OH)2)' These systems impart flame retardancy through heat absorption and by release of water of hydration upon their decomposition. ATH has a low decomposition temperature (230°C), limiting its use to unsaturated polymers, epoxies, urethanes, and some wire and cable formulations. However, some advantages of ATH over halogenated FR are that it is relatively cheap, doesn't generate toxic gases, is non-volatile, and is impervious to moisture [2].

Jan 1, 1997

By Simon C. Dominy, Alwyn E. Annels, Paul Wheeler, Suzanne P. Barr, G. Simon Camm

Narrow veins are an important world-wide source of silver, tin, uranium and particularly gold. To potential ?nanciers, this style of mineralization is viewed as high risk because of the often relatively small resource involved and high cost of estimation. In many cases diamond core drilling will not enable resource estimation beyond the inferred and indicated categories. Exploratory under-ground development is required to de?ne measured resources. The de?nition of geological and grade continuity are major factors in narrow vein assessment. A measured resource must be based on strong geological and grade continuities. Narrow veins, generally less than 3 m wide, are complex geological phenomena, which commonly display unpredictable geometry and grade distribution. Variations in structural continuity, dip, strike, width, mineralogy and speci?c gravity are common. Veins may be composite, with ore-grade mineralization restricted to a speci?c structural domain. Branches, intersections and braided zones are common features. Potentially high-grade zones are often localized within ore shoots, which are surrounded by barren/low-grade regions. Resources must be determined as closely as possible to reality and re?ect the distribution of the commodity in the rock. Estimation has three main requirements: (1) geological study to determine orebody nature;(2) estimation of tonnage and grade, and (3) the presentation of this information using a classi?cation that is clear, unambiguous and bankable. Estimation methods employed are either classical or geostatistical; however, classical methods are often used because of the dif?culties in applying geo-statistics. Grades generally show a strong positively skewed distribution testifying the presence of high-grade values. Problems exist in the applicability of cutting outlier values risking over- or under-estimation of grade. It is generally believed that where resource estimates are in error, poor geological control is usually the cause. Overestimation can lead to the closure of a mine through lost revenue and capital. An understated estimate can result in an opportunity missed for pro?t and/or greater economies of scale. De?nition of reserves involves the consideration of economic and engineering data, to decide which part of the resource is economically mineable. Geology plays a similarly important role at this stage in the assessment of likely mining method, dilution, recovery etc. Throughout resource/reserve estimation, it is crucial that the amount and quality of the data and the geologist’s experience are relevant. The impact of geological understanding on estimation is often undervalued or assumed to be of lesser importance than ?nding grades and tonnages. This paper discusses the geology of narrow vein deposits and the importance of geology in their evaluation.

Jan 1, 1997

By Andrea Bernardes

Printed circuit boards (PCBs) of varying compositions have been converted by incineration and following melting into an environmental agreeable slag and a copper-nickel-tin alloy, containing the precious metals. The environmental compatibility of the slag was determined according to the German standard DIN 38414 - Part 4; pollutants' concentration in the lixiviates is smaller than the thresholds of drinking water (CE-Standards). Each experiment the charge were 500g scrap from PCBs and ca. 100g slag forming material. The products were a kind of mullite slag, poor on iron, which was recirculated, and an alloy containing up to 0.3% Gold. With a burner to the retort coal gas, the waste gas was burned without soot, and the produced mixed zinc-lead oxide containing silver was collected in the flue dust.

Jan 1, 1997

By D. Williamson

In the post war years metals analysts and statisticians have generally tracked the demand for metals in line with changes in OECD industrial production (IP) growth rates because, undoubtedly, the correlation between IP growth and metal demand was reasonable. However the correlation was exaggerated. During times of expanding IP growth metal demand increased at a faster proportional rate than IP growth. This was probably due to industry restocking in anticipation of growing demand at the start of each economic cycle. Conversely, metal demand would slacken at a greater rate than would be suggested by negative IP growth as industry destocked in order to reduce costs. Nonetheless, overall, a reasonable correlation between IP growth, over the longer term, and metal demand could be painted. Yet, although this correlation has stood well since the last world war it has been based on the fact that the bulk of the world's IP growth stemmed from the industrialized countries of the western world, latterly including Japan. The so called "developing world" was of little consequence, whilst countries of the Soviet Union and Communist Bloc were deemed to be closed, self-contained entities which, for each metal, would either be net exporters or importers. These quantities would be used by analysts to calculate the overall supply/demand equation for the western world only and to deduce whether a commodity was in shortage or surplus. It is now believed that this method of projecting total world supply and demand for raw materials is outdated and takes little account of the worldwide political changes which have occurred since the collapse of communism and the revitalization of China, albeit under a notional communist government. It is no longer appropriate to assess global balances for raw materials on the basis of three economic blocs namely, western world, developing world and communist bloc. Rather, global balances need to be projected on a global basis. In this regard, since the collapse of communism and the removal of many other totalitarian regimes, capitalist forces are at work and are attempting to satisfy, with some considerable success, the expectations of the great mass of the world's poorer people. Such people, usually located in Asia, Africa and Latin America have aspired to the same standard of living as people living in western Europe, North America and Japan. Now, with free market forces at work their aspirations will start to be met. Consequently, the demand for metals and other raw materials will now rise at a much faster rate than at any other time in the world's history. Not only will the production of raw materials have to keep pace with rising IP in the developed world but will also have to keep pace with the demands associated with the rising expectations of rapidly increasing populations in the developing world, as well as from within the old communist bloc countries. This paper sets out to argue the case that metal demand could well increase at a rate faster than the world's mining companies, governments and financiers can deliver.

Jan 1, 1997

By Harold L. Gibson, Don H. Rousell, Ian R. Jonasson

"Abstract - The Sudbury Structure consists of three major components: 1) the Sudbury Basin; 2) the Sudbury Igneous Complex which surrounds the basin as an elliptical collar; and 3) an outer zone of shatter-coned and intensely brecciated footwall rocks. Although the Sudbury Event which formed the structure may be unique, the area has, in fact, been shaped by a series of tectonic, magmatic and mineralization events which can be considered in terms of two Wilson cycles of continental extension and closure. The first cycle, from 2500 to 1700 Ma, included the following events: doming (uplift of Levack Gneiss Complex); NE-SW extension (Matachewan dikes); N-S to NW-SE rifting (faults, mafic intrusions, sedimentation, and Ni-Cu-PGE and U mineralization); NW-SE extension (Nipissing diabase, and Ni-Cu-PGE, Ag, Co mineralization); and NW-SE and NE-SW closure (Penokean Orogeny, 1900 to 1700 Ma) with superimposed meteorite impact (1850 Ma, Ni-Cu- PGE, Zn-Cu-Pb deposits). The second cycle, from 1700 to 1000 Ma, included: N-S extension (alkali metasomatism, Au); N-S extension (hornblende diabase dikes along the Murray fault set); NNESSW extension (olivine diabase dikes); NE-SW extension (Fecunis Lake fault set); and NW-SE closure (Grenvillian Orogeny).The rich and diverse Ni-Cu-PGE and subordinate Zn-Pb-Cu and Au mineralization of the Sudbury region is related to endogenic and impact-triggered crustal extension and magmatism. The Sudbury Structure apparently was the site of a triple junction or hot-spot. The Sudbury ores, although located within an impact structure, are analogous in terms of age and tectonic setting to Ni-Cu-PGE and Zn-Pb-Cu ores elsewhere in the world. Meteorite impact accentuated on-going ore forming processes and magmatism at Sudbury."

Jan 1, 1997

By John Wallace, Chib Iheagwara

"Refinements in sensor design have produced low-cost rugged elements to act as loop coupled with stable detection hardware for eddy current measurement in difficult environments. This has allowed direct dimension gauging of nonferrous and ferrous products above the curie point for absolute dimensions and electrical conductivities independently. The software was developed for the analysis of electrical conductivity profiles in CZ silicon crystal growth, then refined for monitoring bar properties and tube properties. Since in most metal working operations, speeds at the minimum of a few hundred feet per minute are encountered the design of the gauge was optimized for a rapid measurement. Independently extracting electrical conductivity provides data in some metal systems for determining the temperature of the monitored product.IntroductionThe primary reason for the use of eddy currents in gauging is that in hostile environments of metal working techniques such as laser gauging and ultrasonics are not always robust enough for in process measurements. Our goal is to use the technique of eddy current measurement as a quantitative control element in various hot and cold processing operations. Inspection in the early stages of metal and semiconductor processing is usually too costly to introduce in a well developed process and these tools are usually only employed in process development. Until recently there has been no efficient general analysis to allow real time measurements in the cylindrical and the probe geometry that could separate dimensional changes from material property changes both which effect the eddy current response. The basis for these measurements is that forward electromagnetic problem for conductors can be solved exactly for the test geometry which allows an inverse analysis to be made by relaxing the dimensions and conductivity to values which reproduce the measured response[!]. This transformation is based on analysis developed in Robert Siegfried' s thesis and was explored both by modeling and by physical measurement. This analysis was extended over the last few years to allow a more compact data set to be used to exact physical properties. The main result was that the technique would work on high ·quality physical data on as little as three test frequencies with the penalty being that the analysis is computational intensive. The main result of this work was that a quantitative inverse analysis of eddy current response would allow a general instrument to be used for a variety of measurements rather than being tailored for a specific measurement on a specific material test geometry. The development of these instruments has progressed over the last ten years for monitoring real time solidification, crystal growth[2] and hot seamless tube forming where the use of standards in traditional eddy current is limiting. The specific instrument design was dictated by the requirements of the algorithm for both frequency selection and levels of systematic noise that could be tolerated. Because the data is need for real time information this dictated that the system be a parallel multifrequency eddy current instrument feeding the same sensor. The sensor have to be simple and robust and usually a single loop or several loop of heat resistant wire or tube. This presentation is about using inversion of multifrequency eddy current data in real time to produce dimensional and property data on cylindrical conductors and planar conductors in real time. The object of the measurements is to produce dimensional outputs on measurements of conducting material without having to establish a detailed standard for each material or size tested. The dimensional measurements using eddy currents is complicated by material variations in conductivity due to temperature and composition. Those variations that are not geometric are often not of critical interest and complicate the measurement. The dimensional changes are often of more importance"

Jan 1, 1997

By M. C. Bétournay, J. E. Udd

"The Mining Laboratories of CANMET are the principal federal government vehicle for the delivery of mining research in Canada. With research being performed at five locations, which are mostly mining communities, the laboratories are in close proximity to the industry which they serve.The Mining Laboratories have three principal roles: (1) to support government in its development of policy; (2) to aid industry in the enhancement of productivity; and (3) to improve the health and safety of Canadians,both in the workplace in mines and around abandoned mine sites.From 1994 to 1996, CANMET’s mining research was re-focused into four programs. These are: (1) Underground Mine Environments; (2) Mine Mechanization and Automation; (3) Ground Control, and; (4) Coal Mining Health and Safety.In this paper, the authors outline the work of the Mining Laboratories and also identify the areas considered to be primary targets for future mining health and safety research in Canada."

Jan 1, 1997

By L. Larrimore

Electric utilities depend heavily on coal as a major fuel source for power generation, annually producing more than 85 million ton'> of ash, boiler slag and FGD (flue gas desulfurization -"scrubber") materials as by-products. Utilities and others who burn coal have traditionally disposed of these by-products in ponds or landfills. However, in the last 10-15 years there has been a greatly increased emphasis on beneficial utilization of these materials by the producers themselves as well as by customers who purchase the by-products. Regulatory, cost and technical performance issues currently impact the use of coal ash and other coal combustion by-products (CCB).

Jan 1, 1997

By T. Owen

Not since 1917 has a foreign company developed a standalone, grass roots gold mine in Russia. With. Russia's political changes of the late 1980s, development of mineral prospects once again beckons foreign investors. In 1990, Cyprus Amax began aggressively searching for such an opportunity. Early in 1997, production will commence at the Kubaka gold project located in the Russian Far East, near the Arctic Circle. The Kubaka project is a 1,750-tonne per day open-pit operation that will produce more than 300,000 ounces of gold per year. This paper discusses the challenges of locating such a prospect, doing business in Russia, developing supply lines, identifying work force capabilities, gaining government approvals, securing financing, arranging for gold sales and ultimately building a facility in this arctic region.

Jan 1, 1997

By Flavio Begazo, William A. Enrico

"Southern Peru Copper Corporation's Ilo Refinery, the largest in Peru, began operations in 1975 with a production capacity of 165,000 stpy. Southern Peru bought the Refinery from the state owned Minero Peru SA on June 1, 1994.The Refinery processes blister from Southern Peru's I/o Smelter. Blister copper is processed in an anode plant equipped with two 365 st tilting reverberatory furnaces, a 26 mold casting wheel and an anode press machine. Copper is electrorefined in a tank house equipped with 768 commercial cells, 44 stripper cells, and 40 liberator cells, utilizing two electrolyte circuits and a 21,000 Ampere rectifier.During 1989 through 1994 a program for improving productivity was carried out by increasing the number of cells and increasing current density to the total rectifier capacity. As a result, a capacity 215,000 stpy of refined copper, 2 million tr. oz silver and 6,000 tr. oz gold per year was achieved. In 1994 Southern Peru announced plans to increase capacity to 250,000 stpy of cathode with a US$ 18 million investment and a US$ 2 million investment in environmental improvement projects, as part of the purchase agreement with the Peruvian government.This paper outlines the scope of the SPCC lio Refinery modernization and environmental program. It describes the implementation of the Electrolytic Plant expansion based on instaliation of polymer concrete cells, a new rectifier, a new selenium roaster and a Precious Metal Plant upgrades."

Jan 1, 1997

By N. Merriam

This report describes Koppelman's work to develop the K-Fuel® Series C Process used to dry and stabilize Powder River Basin coal. It also contains summaries of the results of bench-scale and pilot plant tests conducted to prove the Series C Process. The process is being used by the KFx-Thermo Ecotek partnership for a 500,000 ton per year commercial plant that has been constructed near Gillette, Wyoming. The plant is presently undergoing shakedown.

Jan 1, 1997

Coal is a combustible, carbonaceous, sedimentary rock that is formed by the accumulation, compaction, and physical and chemical alteration of vegetation [Simon and Hopkins 1981; Bates and Jackson 1987]. Coal is classified according to its type, grade, and rank. The type of coal relates to the plant materials from which the coal originated. The grade of coal refers to the purity of the coal-or the amount of inorganic material (including ash and sulfur) left after the coal is burned [Bates and Jackson 1987; Stefanko 1983]. The rank of coal indicates its degree of metamorphosis and roughly correlates to the geological age of the coal or the geological environment from which it has been mined [Bates and Jackson 1987]. Rank also indicates the percentage of carbon in dry, mineral-free coal [Whitten and Brooks 1973] and the degree to which the coalification process has progressed [Larsen 1981]. The geological process of coalification begins with organic materials (e.g., celluloses, lignins, and other plant compounds that are deoxygenated and then dehydrogenated) and ends with coal of various geological ages, from lignite to anthracite [Larsen 1981]. Table 3- 1 presents the American Society for Testing and Materials (ASTM) classification of coals by rank. According to Parkes [1982], high-rank coal includes anthracite and semianthracite coal ("hard coal," with 91% to 95% carbon); intermediate-rank coal includes low-, medium-, and high-volatile bituminous and sub-bituminous coal ("soft coal," with 76% to 90% carbon); and low-rank coal includes lignite (with 65% to 75% carbon or less). The rank of coal tends to increase from the western to the eastern United States, with anthracite occurring primarily in eastern Pennsylvania [Schlick and Fannick 1971]. Most of the coal currently mined in the United States is bituminous [Given 1984]. A classification of the coal in the United States is provided in Table 3-2.

Jan 1, 1997

By M. S. Klima

Proper analysis of washability data can lead to the development of a maximum yield coal preparation plant flow sheet. Simulations, as simple as spreadsheet mass and water balancing, are important in examining yield maximization and middlings liberation. Key to such attribute tracking flow sheet simulations is the distribution model, expressing the probability of a species reporting to the product stream. There are many such models in the literature. This paper examines a functional form that can represent or fit most of the proposed distribution functions.

Jan 1, 1997

"Option pricing is used in finance for valuing options to buy (or sell) shares at some future date because it provides a convenient framework for quantifying values subject to uncertainty. As one of the main sources of uncertainty in mining is the price (sales) of the metal, this approach can also be used for valuing mining projects.The first part of this paper reviews options and option pricing; the second part presents the approach developed by Brennan and Schwartz (1985) for using option pricing to value natural resources. Several applications of this methodology have been published; these are described. From a mining point of view, the assumptions made by Brennan and Schwartz are too simplistic. The weaknesses are discussed with a view to improving an apparently promising new way of assessing the value of projects. IntroductionThe collapse of the British merchant banking group, Barings, has highlighted the risks that can be incurred by speculators and arbitragers in the futures and options markets. But this negative attention on futures and options should not make us forget their positive aspects. They can provide producers and consumers of metals with more predictable sales prices. The introduction of the new traded average price options, TAPOS, by the London Metal Exchange in January 1997 is a response to this need. Equally important, the theory that the finance industry has developed for valuing options provides an interesting framework for valuing mineral projects as well. While this paper was being revised, the South African gold mining house, JCI, announced that it was using a methodology based on option pricing for valuing the mineral rights to deeplevel gold resources (see Box 1)."

Jan 1, 1997

By Claude Lorenson

"The Spyrometer™ imaging pyrometer brings new dimension of imaging capabilities to temperature measurement technology by combining a high temperature video camera with scanning optical pyrometry. This gives the operators the ability to observe process conditions while measuring the temperature of virtually any object or region in the field of view. Since the lens tube of the camera can be air or water cooled, it is possible to see inside furnaces giving a very good view of many different types of metallurgical processes. Specific benefits in process knowledge and maintenance tasks for furnaces in different types of metal industries are discussed.1-Principles of Imaging PyrometryLens tube, camera and processorImaging pyrometry is the combination of video imaging and computer-driven pyrometry that measures the temperature of certain zones (selected by the operator) within the image viewed on the monitor screen. To obtain a detailed image of the metallurgical process under observance, it is necessary to place the optical objective of the camera close to the process. The Spyrometer™ (which is Quadtek's tradename for its imaging pyrometer) objective is housed in a lens tube that is cooled and permits insertion inside the vessel of interest. The length of the lens tube is chosen on the basis of making sure that the tip of the tube is just beyond the refractories lining the inside of the furnace. In most pyrometallurgical processes, we have found that the most reliable system set-up uses a water cooled shroud to cool the lens tube optics. A sapphire window provides maximum protection from the environment. Even in the case of the water cooled version, there is an air purge for the lens that keeps the objective clean and protects against hot metal splashes."

Jan 1, 1997

By J. G. Groppo

Laboratory settling and filtration testing was conducted on wet processed fly ash in order to determine the applicability of conventional dewatering techniques to reduce the moisture content prior to drying. Settling tests showed that acceptable clarity (<1.5 g/l suspended solids) could be achieved after as little as 6 minutes of settling. After settling to a consistency of 40 weight % solids, continuous laboratory vacuum filtration testing produced a cake containing below 20% moisture with throughput exceeding 150 lb/ft2/hr.

Jan 1, 1997

"Mixing phenomena in a bottom blown air-stirred one-seventh water model of CLU (Creusot-Loire Uddeholm) reactor was studie9-using three different configurations of straight circular nozzles fitted axially at the bottom of the vessel. The mixing time has been determined by pH measurements at various gas flow rates, bath heights and nozzle orientations in the presence and in the absence of a second phase.Experimental results reveal that the mixing time decreases with increasing gas flow rate. For a given gas flow rate the mixing time increases non-linearly with increasing bath height. Off-center configuration gives slightly lower mixing times as compared to center configuration. It is found that the contribution of buoyancy to the total stirring energy density is very small, but its contribution increases with increasing bath height. In the presence of an upper oil layer, the mixing time increases significantly for all configurations.IntroductionIn high temperature metallurgical melts mixing is carried out by injection of a gas either from top or bottom of the vessel in order to accelerate the rates of chemical reactions and to promote bath homogenization. When a gas is injected into a liquid through a submerged lance, porous plug or nozzle, the gas, rising as a two phase plume to the surface, imparts momentum to the surrounding liquid and causes gross circulation in the bath which promotes mixing."

Jan 1, 1997

By D. A. King

Monitoring devices have been installed at several mine sites to assess the potential for the development of acid rock drainage (ARD) in waste rock, spent ore, and tailings material. In addition, instrumentation has been designed for monitoring changes in water quality in pit lakes. These devices monitor temperature, oxygen, water movement, and water chemistry in the waste rock pile. This information can be used to evaluate the current and future ARD risk, the effectiveness of caps and covers, and provide information to aid in the design of other reclamation strategies that limit ARD development. The instrumentation includes nested thermistors and oxygen sensing ports, neutron access tubes, heat dissipation units (HDUs), and lysimeters. Many of the monitoring devices can be linked to a datalogger and telemetry systems, enabling monitoring data to be downloaded from the office.

Jan 1, 1997

By M. T. Ityokumbul

Concentrate flowrates have been measured for the flotation of -100 mesh Lower Kittaning coal in a computer controlled 0.076 m x 3.5 m pilot flotation column. The variables studied were recovery zone height), air flow rate, and solid feed concentration. The size distribution of concentrate and tailings samples were determined. The results obtained show that the concentrate flow rate was independent of collection zone height, but dependent on the gas flow rate, solid loading and particle size. New correlations for column carrying capacity and yield are provided as a function of these fundamental operational parameters.

Jan 1, 1997

By Michel Lefebvre, André Piché

Every organization performing R&D is faced with the challenge of introducing new technologies to its operations. Difficulties must be overcome if companies are to realize the benefits anticipated from such developments. This paper outlines the difficulties encountered in transferring to operations various technologies developed at the Mining and Exploration Division of the Noranda Technology Centre. The approach used in the selection of a privileged partner for the technology transfer, the criteria motivating the choice and the process followed to establish the partnership are presented.

Jan 1, 1997