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By M. K. Walter

"The underground operations of Kidd Creek Mines uses an average of 450 U.S. gpm water during regular operations, and discharges an average of 800 U.S. gpm through consecutive staged pumping lifts of 1200f t.Water is used as a flushing medium for the drilling operations and as a dust suppressant for drawpoint mucking. The water retains an average of 5% suspended solids by weight which is removed underground before being pumped to the surface. This paper outlines the treatment of the mine water for the removal of suspended solids which are chemically treated to settle out as a sludge product of 60% solids by weight. This process reduces the sludge handling operation by 50%. The sludge is systematically disposed into the ore passes.IntroductionThe Kidd Creek minesite, located 27 km north of Timmins, Ontario, produces 4.5 million tonne s of copper, lead, zinc and silver ores annually from its No. I and No.2 underground mining operations. Both mines use a sublevel blasthole stoping method of extraction.Water from the underground operation passes through a series of surface settling ponds, where it is treated to remove heavy metal ions from solution. A blend of the pond effluent with fresh water from Kidd Creek, supply the underground with water at an average rate of 450 U.S. gpm. Water flows from the production zones through coarse sumps and into a main pumping station. There are five main pumping stations underground, three in No. I Mine and two in the No.2 Mine.The No. 2 Mine pumping stations are located on the 4800 level and the 3600 level. All water below the 3600 level to the shaft bottom is controlled from the 4800 pumping station. The water from the 4800 pumping section is combined with water from the remaining levels of the No.2 Mine at the 3600 pumping station. Water from the 3600 pumping station is pumped to the 2400 pumping station in No. I Mine.The No. I Mine pumping stations are located on 2800, 2400, and 1200 levels. All water below the 2400 level to the shaft bottom is controlled through the 2800 pumping station. This water is pumped to the 2400 pumping station. The 2400 pumping station also controls the water below 1600level to 2400 level."

Jan 1, 1988

By Youjun Tao

Falcon centrifugal gravity separation tests were conducted to study desulfurization and de-ashing performance with different size fractions of a high-sulfur Chinese -0.5mm fine coal in a dense medium. Performance indicators such as combustible recovery, ash and sulfur rejection, and desulfurization efficiency were used to evaluate the separation efficiency. The results show that for -0.5 mm coal particles, all performance indicators except ash rejection are higher for the Falcon concentrator than for flotation. More specifically, for the +0.125 mm size fraction, Falcon centrifugal separation produced better ash and sulfur rejection performance than froth flotation. However, the Falcon concentrator also showed higher combustible recovery but lower ash and sulfur rejection than froth flotation for the -0.125 mm size fraction.

Aug 1, 2013

By Charles T. Harper

The uranium deposits discovered by Amok (Canada) Ltd. in the Cluff Lake area of north western Saskatchewan occur at or near the southern edge of the uplifted basement core of the Carswell circular structure. Two types of mineralization, distinguishable, by their geological and structural setting and mineral paragenesis, have been recognized. The N-Claude type is characterized by a relatively simple mineral assemblage, consisting of uraninite or pitchblende with coffinite, and is accompanied by variable amounts of graphite and organic matter, and Fe, Cu, Pb and Mo sulphides. Both N and Claude orebodies occur within quartzofeldspathic gneisses of the basement core. On the other hand, the D-type ore has a complex mineral assemblage consisting of: uraninite, pitchblende, thucholite and coffinite, along with native gold and selenium; gold tellurides, and selenides of Pb, Bi, Ni and Co; sulphides of Fe, Cu and Pb; and organic matter. The D orebody occurs within carbonaceous shales at the base of the Athabasca Formation as well as in fault zones in regolithic quartzo feldspathic gneisses above the inverted unconformity. An age of 1050 m.y., which is consistent with a period (circa 1200-1000 m.y.) of widespread hydrothermal activity and uranium mineralization or reworking within and adjacent to the Athabasca Basin, has been obtained from uranium mineralization from the D orebody. Later reworking (circa470 m.y.) of the mineralization occurred at the intersection of older mineralized shear zones with radial faults produced during meteorite impact.

Jan 1, 1978

By Aparup Chattopadhyay, Barun K. Gorain

"Porphyry copper deposits are the most important source of copper and also gold within the orogenic belts. These deposits are characterized by low grade copper ore (0.2% to 1% copper) and host precious metals like gold, silver and platinum. A characterization tool has been developed for complex porphyry type copper-gold deposits with an aim to quantify copper and precious metal deportment. This quantification is a challenging task due to low grades and also due to the presence of both visible and invisible precious metal content in different sulphide and non-sulphide phases. Studies were initiated on various complex ore deposits and also on samples representing various processing streams such as flotation and leach products. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metals content in various species. The relevance of this characterization to metallurgy will also be briefly discussed in this paper.INTRODUCTIONA novel characterization tool has been developed for double refractory gold ores and complex copper-gold ores using state-of-the-art technology for quantitative gold and copper deportment study. The characterization of these ores is a challenging task due to low copper and gold grades in ores, presence of both primary and secondary copper sulphide phases and variable proportion of visible and invisible gold in different sulphides phases (pyrite, chalcopyrite, chalcocite and bornite) and iron oxide phases (magnetite, hematite and goethite). A study was initiated on various ore deposits and also on samples representing various processing streams of pilot plant batches such as flotation concentrates and tailings. This paper attempts to discuss the deportment characterization methodology through presenting results from investigations on four samples from a flotation circuit viz, Feed, Final concentrate, Cleaner Scavenger Tail and Rougher Tail samples. These four samples represent the key streams for a typical copper-gold flotation flow sheet. The key objective of this investigation was to identify and quantify visible and invisible gold along with understanding the morphology and liberation of gold associated with various sulphides, Fe- Oxides and non-sulphide gangue species. In addition, the aim of this study was also to relate this mineralogical and gold deportment information to metallurgical performance."

Jan 1, 2013

By J. Jung, W. Keller, A. Zucht

"The agitator design for nickel high pressure acid leach autoclaves (HPAL) is critical with regard to the process result, i.e., the recovery rate. Further considerations during the design phase are the avoidance of acid hot spots which reduce the lifetime, due to corrosion of the wetted parts, including components manufactured from titanium. Besides the process knowledge to design HPAL autoclaves, tools such as, Computational Fluid Dynamics (CFD) supplemented by lab testing allow the design of optimized agitation systems. This paper describes the effect that different feed point locations have on instantaneous blending of the reactants. Furthermore, experiments and CFD show where abrasion issues might occur and how to obtain information about the static and dynamic forces acting on internals. We show how simulations can be validated by lab testing to ensure that the CFD models are applied in an appropriate way.INTRODUCTIONAgitated systems in hydrometallurgical processes have to comply with multiple process tasks and in many cases have to withstand extreme operation conditions such as pressure up to 50 bar, elevated temperatures of up to 250°C and exposure to very acidic or alkaline environments and abrasive ores. The process tasks range from instantaneous mixing of reactants, homogeneous suspensions of up to 65% wt. solids with coarse and heavy particles, enhancing the solid-liquid mass transfer for leaching, dispersing large volumes of reactants (gas-liquid, liquid-liquid mass transfer) and moreover to transport generated heat e.g., from exothermic reactions through the vessel walls or internal heat exchangers if required. For economies of scale, agitator systems have reached sizes of 5000 m³ for large open leach tanks with impeller diameters of approx. 6 m, while autoclaves nowadays have exceeded 5.5 meters in diameter with a power demand for a single compartment drive between 300 - 400 kW. In parallel all process industries require a more efficient use of resources, to generate less by-products and higher yields, while ore-bodies tend to be less qualitative and new process routes (e.g. direct leach) are developed. Besides all these facts the mixing solution must be robust and economic. In this paper we want to address our approach in the development and designing of HPAL agitation equipment."

Jan 1, 2012

RÉSUMÉ Cet article traite d’une analyse technique et économique du concept du triage optique en vue d’améliorer la rentabilité des opérations minières. Le principe du tri optique et les principaux systèmes et modules servant au fonctionnement de l’appareil de triage sont décrits. un modèle a été développé pour analyser l’intérêt économique d’une opération de triage optique. L’étude est basée sur des données provenant d’une halde de minerai à faible teneur en or, déposé à la surface, et de minerai extrait des opérations souterraines courantes de la mine Beaufor au Québec. Les résultats de cette analyse indiquent que l’opération de triage optique permet d’améliorer grandement la performance économique; l’opération devient alors rentable pour des teneurs en or relativement petites.

Jan 1, 2010

By D. G. Tisdale, W. Curlook, J. M. Toguri

"In this study, the vapour phase reduction of titanium tetrachloride conforms to the traditional Kroll chemistry, but employs argon as an inert carrier gas and requires a higher reaction temperature of 1150°C to 1250°C. A vapour phase reaction is advantageous because titanium is the only condensed phase present, and the metal can be collected free of magnesium or magnesium chloride, in marked contrast to the titanium sponge produced by the conventional Kroll process. The yield of metallic titanium from the reaction was determined as magnesium additions ranged from 36% to 168% of the stoichiometric requirement. Yields of over 99% were obtained when an excess of magnesium was present. Although the collection efficiency was low, metallic titanium was collected at the reaction site, where all other species were present as vapours. Magnesium and chlorine concentrations in the collected titanium were less than 0.3%.IntroductionA proposed method (Curlook, 1987) for titanium production has been investigated as an alternative to the conventional Kroll process (Kroll, 1940). The advantages of the new process include a simplified means of recovering the product metal, and a potential for lower overall energy consumption and greater product purity. A higher reaction temperature for the reduction of titanium tetrachloride results in a vapour phase reaction, rather than the conventional liquid phase reaction. This is the major conceptual difference between the proposed and the established (Kroll) processes.This study focussed on optimization of the process chemistry and briefly examined the issue of product deposition and collection. The reduction of titanium tetrachloride with magnesium, to produce metallic titanium and gaseous magnesium chloride:"

Jan 1, 1997

By Oliver Hall

WITH the friendly consent both of the Institution of Mining and Metallurgy, for whom this paper was written, and of the author, we had the pleasure of publishing Mr. Oliver Hall's paper on Mining at Noranda in our issue of last March and of having Mr. Hall present it at the Montreal Meeting. In the following pages we now report the discussion elicited by the paper at a meeting of the Institution in London on March 18th. The report is taken from the April, 1937, issue of the Bulletin of the Institution, to whom we again tender our thanks. THE PRESIDENT (MR. ROBERT ANNAN) said that this paper was, by arrangement with the Institution and the author, also being published by the Canadian Institute of Mining and Metallurgy for approximately simultaneous discussion. He was sorry that Mr. Oliver Hall could not be present to introduce it in person, for he was sure that the author would have had many more details to give about this most interesting mine. The paper contained a very useful account of mining operations, and personally he had been pleased to see the tri-dimensional projections of the orebody in Figs. 3 and S. It was a good illustration o the value of that method in presenting the form of an orebody such as this. While he had no desire to go into technical details, he wished to call attention to a remark in Mr. Hall's introduction, in dealing with the history of the mine and the principles on which it was run. The author had given an account of the early difficulties in solving geological problems, and later of the economic difficulties of seeing this mine through a period of intense depression in metal prices. He stated that it was clear that, to maintain income, tonnage must be increased, and, to maintain profits, costs must be decreased. It would be observed that there was no question of increasing the grade of ore. Then the author went on to say: 'Having set the house in order in the years of adversity, the higher price for gold is being used to mine to still lower limits and lengthen the life of the enterprise and the welfare of those dependent on it'.

Jan 1, 1937

By P. C. Parsons, G. C. Milligan

"IN FIELD WORK in the Cape Breton Highlands, which are heavily covered with vegetation, it is necessary to run traverses along the valleys of small brooks. We encountered difficulty in closing such traverses, and the following technique was developed to solve this problem. It has been tested in the field for four seasons by several people, and found to be simple, efficient and more accurate than any other compass-and-pace system of which we are aware. So far as we can find, the technique has not been described previously. It may be of use to others.The Cape Breton Highlands of Nova Scotia consist of hills of old intrusive and metamorphosed sedimentary rocks protruding up to 1,000 feet above the general level of the younger sediments which underlie the valleys. The flat hill-tops are the remnants of a plateau; drainage off the edge of this plateau has produced many small steep brooks. They occupy valleys which are up to 800 feet deep, and V-shaped in cross section, with steep sides covered by mixed conifers and hardwoods. The stream at the bottom is rarely more than a few feet wide, with a negligible meander belt, but with many bends, rapids and falls. Visibility along the stream, in consequence, is rarely more than a few hundred feet, and in many places much less.It was found impractical to map the streams by the method of meander lines, as described in many standard surveying texts and hand-books. The limited visibility, and the numerous bends of the brooks, necessitated many corners. Every corner introduces errors. To 'close' a survey with 40 or 50 such corners proved either very time-consuming or impossible. In most cases, however, the general direction of a valley may be obtained from an aerial photograph, or by direct observation, and this became the basis of the method adopted."

Jan 1, 1971

By Bryon Cerklefskie, Michael Schulte

"This case study explores the usage of polymer ducting as a replacement to curtains and FRP for face ventilation in two coal mines. There are two mines looked at, one is the highest elevation underground coal mine in North America, the other is the gassiest mine in North America. The paper details the trials of both mines switching from FRP and curtain respectively to polymer ducting. The results discuss the ability for the mines to not only achieve consistent airflows and keep them in compliance but the unexpected positives. Mine A was allowed to do longer cross cuts due to increased air volume at the face. This drastically cut their costs of mining down due solely to modification of the ventilation cycle. Mine B saw economic benefits due to longer cuts between place changes. Both mines have documented lower dust, methane, noise, and improved wear and tear on their equipment as a result.INTRODUCTIONThe emergence of longwall mining in underground coal operations has resulted in new ventilation challenges. Numerous production crews strive to complete their development sections with enough time to adequately prepare for the upcoming longwall panel. Continuous miners will cut out two or three entry development sections per their ventilation plan, that is approved and controlled by MSHA (Mine Safety and Health Administration), which will drive amount of footage that can be mined at a time prior to installing roof support. At this moment the continuous miner, hereafter referred to as the CM, will back out of the entry and moves to the second entry to complete a similar cut. Typically, a roof bolter crew will pull in to the finished cut section and install ground support. This is called a place change style of production coal mining. There is an alternate method that includes a miner/bolter combination as well but that was not featured at either test site in this case study. Ventilation has to be provided to sweep the working face of each entry to control dust and gasses. Each task will have an MSHA prescribed ventilation requirement dependent on the dust levels and methane emissions of the rock for that particular mine. The CM, roof bolting and unused headings will each require constant ventilation but at different volumes. Since each working face is changing throughout the mining cycle the ventilation requirement in a working heading is never static and is changing with the working task.Traditional Ventilation ControlsTraditionally face ventilation for coal mining operations has been completed thru the usage of a curtain system and\or using auxiliary fans and ventilation tubing. Room and pillar mining systems typically utilize curtain systems, which use curtain walls that are installed by the miners by erecting wood framing and covering it with brattice curtain. This splits the drift width to allow fresh air to sweep the face and take the contaminated air and dust behind the curtain to the ventilation exhaust\return area of the mine. This method is difficult to adjust the airflow from entry to entry during changing cycles and requires that a wider drift is mined out in order to have enough room for the brattice wall. In operations that require roof bolting, this method limits the length of the cuts from the CM prior to advancing and can lead to not providing enough ventilation to keep dust and methane levels below compliance requirements."

Jan 1, 2019

The Mineral Industry of Canada in 1951 Continuance of the remarkable, successive increases in the value -of Canada's mineral production, chief basis of the nation's post-war expansion, was one of the highlights of Canadian development in 1951, when, according to the preliminary estimate is-sued by the Dominion Bureau of Statistics and reported in the BULLETIN for February, 1952, mineral output for the year reached a new high of $1,228 millions. This marked an increase of 17.5 percent over the previous year, which was the first in which the billion dollar mark had been reached, and an increase of 143.7 per cent over 1946, when production was valued at approximately $503 millions. While higher prices for the principal base metals accounted for a large part of the 1951 increase, quantity gains were made by copper, nickel, zinc, asbestos. lead, cement, and strikingly important. by petroleum, the value of which exceeded for the first time that of coal production. Gold was an exception to the general trend, being lower in both quantity and value than in 1950. For the first time nickel .came within $9 millions of surpassing-gold as the leading mineral product. Metals and Fuels The value of all metals, estimated at $733 millions, was 18.7 per cent more than in the previous year. Nickel advanced 11 per cent in volume and 34 per cent in value. Copper was up 2.4 per cent in quantity and 21 per cent in value, zinc rose 6.6 per cent in quantity and 35 per cent in value, and although the volume of lead produced was lower by 8 per cent, its value increased by 17 per cent. The tonnage of iron ore was 31 per cent higher than in 1950.

Jan 1, 1952

By S. B. Ballantyne, D. R. Boyle

"Detailed studies have been conducted on the dispersion of uranium in stream waters and sediments around various types of mineralization and hitherto unexplained anomalous areas in the Okanagan Valley and Highland region of south-central British Columbia. These studies were part of the jointly funded and planned Federal-Provincial Uranium Reconnaissance Program of the Geological Survey of Canada and the British Columbia Ministry of Energy, Mines and Petroleum Resources. Statistical analysis of regional data indicates that U in stream waters and sediments varies considerably for different rock types, thus affecting data interpretation. In addition, the data demonstrate a poor correlation between U in stream waters and their associated sediments which can be largely accounted for by variations in climate and water and sediment composition. Regional trends in the distribution of U can be explained in terms of the above secondary factors as well as primary metallization phenomena.Significant correlations between U and F, and U and Mo can be explained by certain magmatic and mineral-forming processes. U shows little correlation with other base metals.The dispersion characteristics of U in the vicinity of Miocene "" basal type "" mineralization ; uraniferous pegmatite terranes, anomalous lineaments in granitic terranes and high-background volcano-sedimentary areas are discussed. Highly anomalous U concentrations in waters and sediments may not always be indicative of mineralization, and guidelines for interpretation require a sound knowledge of the geological and secondary processes operative in the area."

Jan 1, 1980

By J. S. Fox

Major-element data for unaltered, unmineralized felsic host rocks from a number of stratigraphically simple, massive volcanogenic Zn-Cu(-Pb) sulphide deposits of low metamorphic grade have been compiled. The petrochemical affinities of these host rocks have been determined (by standard means and by discriminant analysis) and compared. This comparison indicates that volcanogenic deposits in felsic terrains are not restricted to the classical calc-alkaline rock association as previously thought, but can actually be hosted by rocks showing a range of iron content. There is a positive correlation between differentiation trend and are tenor. Zn-Cu ores usually have iron-rich felsic hosts (most Canadian Shield deposits); Pb-Zn -Cu ores have iron-poor felsic hosts (Japanese, Iberian and Tasmanian deposits). This parallels the antipathetic relationship between iron content and background lead levels evident in young, unmineralized, island arcs as well as in many older belts. Correlations between differentiation trend on one hand and massive ore mineralogy and the relative proportions of various rock type (including rhyolite, quartz-porphyry and coarse pyroclastic rocks) on the other are also evident. It is concluded that the recognition of a calc-alkaline differentiation trend cannot be used as a prospecting guide, as has previously been proposed. However, in view of the above correlations, the recognition of a given trend may aid in the formulation of an effective exploration philosophy.

Jan 1, 1979

By H. H. Gardner

INTRODUCTION THE problem of mechanization is one of the most vital in the minds of Alberta coal operators today. In these times of constantly increasing operating costs, any way of decreasing the cost of a ton of coal must be explored to the limit. There seems no better field for such effort than the successful application of power to the mining and loading of coal. We are fortunate in having neighbours to the south who have made .remarkable progress in recent times along these lines. Higher tonnages per man have resulted in higher wages to the employee and lower cost to the employer. It might seem that our problems could be solved merely by imitating our neighbours. Unfortunately, neither practice nor experience substantiate this conclusion. It is with the purpose of reviewing our accomplishments, as compared with practice in the United States, and at the request of the Prgoramme Committee for this meeting, that this paper is written. The Committee believes that such a general discussion and comparison may well lead to further advances in our mining methods. SUMMARY OF PRACTICE IN THE UNITED STATES A visit to the highly mechanized coal mines of the United States is always most instructive and encouraging.

Jan 1, 1951

By S. P. Chong, N. C. Shih, G. A. Turner

Fine powders, with the bulk of the particle diameters Jess than 10 microns, were aerated so that each particle was, on the average, separated from its neighbours by 1.3 to 2 mean diameters. In this state, measurements were made of the viscosity and settling rate of the powder, and the interfacial tension between it and a moist pellet. From the viscosity measurements, qualitative analogies are drawn between the behaviour of the aerated powder and that of a dense gas near its critical point.

Jan 1, 1970

By H. W. Manley

SULPHUR, like the minerals of coal, iron and petroleum, is one of the essential materials in our modern expanding industrial civilization. Before discussing the salient features of the production of sulphur from the Canadian sour gas, it seems appropriate to outline the historical past and probable future utilization of sulphur. The ancient Greek writer Homer spoke of its "pest-averting sulphur" and the "divine purifying fumigation". Ancient alchemists found sulphur to be a fascinating and baffling material. The discovery of gun powder in the year of 1250, and its application to the art of war a, century later, made sulphur an important commodity in the progress of mankind. The initial manufacture of sulphuric acid in the year of 1736 by the Englishman Joshua Ward, established the basis of a chemical industry that today utilizes 80 per cent of the consumption of elemental sulphur. Commercial production of the chemical soda ash ( N a2C03) discovered in 1787 by the famous Leblanc Process, in-creased international demand for the element sulphur and marks the birthday of the Sicilian sulphur industry.

Jan 1, 1961

By P. Clinton Milne

Uranium mines in Washington State include the producing Midnite and Sherwood mines and several mined-out deposits, the most productive of which was the Daybreak mine. The Midnite mine is generally classified as a hydrothermal deposit consisting of tabular orebodies in Precambrian pelitic and calcareous metasedimentary host rocks. The host rocks occur as roof pendants in a Cretaceous porphyritic quartz monzonite intrusive; the quartz monzonite averages 12 ppm U308 The uranium deposit appears to have undergone a complex genesis, involving a series of depositional and enrichment stages. The Sherwood uranium deposit, approximately 4 miles south of the Midnite mine, occurs near the bottom of a basal Late Cretaceous to Paleocene arkosic conglomerate. The conglomerate lies nonconformably on the porphyritic quartz monzonite that is associated with the Midnite deposit. The Sherwood and Midnite uranium deposits may have had a similar genetic history linked by a common uraniferous pluton source, ground-water action, and/or leaching of uranium-rich ash flows from now-eroded, overlying, Eocene volcanics. The Daybreak deposit, in northeastern Spokane County, consists entirely of secondary uranium mineralization (metaautunite) in a quartz monzonite pluton. Mineralization is confined to a low-angle fault zone and is most highly concentrated at the intersection of primary and secondary shears. Both hydrothermal and ground-water origins are feasible. Besides the Midnite-Sherwood area, 14 other areas in the western Okanogan Highlands physiographic province and Cascades region have favourable characteristics for uranium potential. Criteria include the existence of uranium occurrences, Tertiary basin sediments with intercalated volcanic and volcaniclastic rocks, favourable geochemical data, alkaline plutons associated with uranium occurrences or borders of Tertiary basins, and structural controls.

Jan 1, 1979

By J .. A. Nemes, I. Ragai

This paper discusses one of the common problems associated with sheet metal forming processes, which is spring back. The materials presented here, stainless steel 410 and Inconel 718, are commonly used in aerospace applications for their superior material properties. Standard tensile tests were performed to determine their tensile properties, as well as material anisotropy. In addition, the effect of anisotropy on springback was assessed experimentally through simple multiple-bending experiments in different directions to the rolling direction. Finally, draw-bending experiments were carried out to study the effect of forming conditions, such as blank holding force, on the final springback angles of the formed parts. For both materials, it was found that the R-values measured for different sheets exhibited variation. However, the specimen orientation does not have a large effect on material tensile behavior or springback angle for simple bending. For the Inconel 718 specimens, the springback angle slightly increases with each stage of deformation during multiple bend experiments. The effect of the blank holding force on springback angles was also examined and found to have a significant effect on thin specimens.

Jan 1, 2006

By J. F. Adams, V. G. Papangelakis

Chemical modelling is becoming increasingly useful in the development, analysis, design, and control of hydrometallurgical processes. The paper presents the development of reliable databases for chemical modelling of selected hydrometallurgical systems using state-of-the-art software, such as OLI. The modelling strategies are also demonstrated. The high pressure acid leaching (HP AL) of laterites, oxygen solubility in the oxidative leaching process of zinc sulfide, gypsum solubility and lead chemistry in mixed sulfate-chloride solutions are presented as case studies. This on-going work attempts to bridge the gap between theoretical research and industry needs. Computational Analysis in Hydrometallurgy 35th Annual Hydrometallurgy Meeting held in conjunction with the 44th Annual Conference of Metallurgists ofCIM Calgary, Alberta, Canada Edited by

Jan 1, 2005

By B. A. Monkman

"IntroductionONE OF :THE most effective methods by which the construction industry is combatting mounting building costs is by making increased use of lightweight materials, thus reducing the dead load to be carried •by structures. This applies to non-metallic materials as well as to metallic ones, and particular attention has been given to developing lightweight aggregates for use in concrete.The use of lightweight aggregates is not new and, in fact, dates back to the Roman Empire, when pumice was used in the walls and domes of the Roman buildings. More recently, and up to a decade or so ago, the demand for these aggregates was met from deposits of volcanic cinders, pumice, scoria, etc., and from the by-products of blast furnaces and coal burning boilers. However, these sources of supply are no longer sufficient to meet the demand, for transportation costs pretty well restrict the use of the natural lightweight aggregates to the western cordillera regions where the deposits of these materials occur, and the use of expanded slag aggregates to the areas neighbouring the plants where slags are produced. As for cinders, the supply has been greatly reduced by the conversion of industry to fuel oil, natural gas, and powdered coal, and the large stockpiles which existed previously have been pretty well exhausted.Industry's approach to the problem of a decreasing supply, in the face of an increasing demand, has been characteristically direct. The solution has been to construct plants whose sole .purpose is to produce economically an acceptable light-weight aggregate from materials close at hand."

Jan 1, 1955