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By M. Frenzel, D. Ebert, K. Bachmann, A. D. Renno, R. Möckel, J. Gutzmer, J. Krause

With the increasing demand for metalliferous and mineral raw materials and the consequent depletion of the global natural resource base, the possible utilization of secondary raw material sources is receiving more and more attention. In the present study, we present results from a detailed vanadium deportment study of three basic oxygen furnace slag (BOS) samples known to containing elevated bulk concentrations of vanadium. Complementary analytical methods that were used to quantify the abundance and composition of V-containing phases include SEM-based automated mineralogy, X-ray fluorescence analysis, and X-ray powder diffraction as well as electron probe microanalysis. The vanadium deportment was quantified using Monte-Carlo simulations of the data obtained from automated mineralogy and electron microprobe analysis. The total V concentrations identified by XRF are between 1.7 and 2.2 wt.% V. The most important hosts of vanadium are larnite-, brownmillerite- and portlandite-solid solutions. In two samples Ca carbonates also significantly contribute to the V deportment, while wuestite, lime, and native iron do not contribute significantly to the vanadium deportment. A thorough consistency check identifies considerable uncertainties in the density of the V-bearing phases as the most likely reason to explain remaining discrepancies between measured and calculated V values.

Oct 14, 2023

By Gerald Sherman

MINING asbestos ore by caving at Thetford Mines, Quebec, has been described in the Transactions of the Canadian Institute of Mining and Metallurgy in papers presented by the staffs of The Asbestos Corp. Ltd., in 1934, and Johnson's Co. Ltd., in 1941. The production by caving prior to 1949, in round figures, has been 14,500,000 tons of ore by The Asbestos Corp. and 5,500,000 by Johnson's Co. They are the only caving operations in asbestos at the present time. The Jeffrey mine of the Canadian Johns-Manville Co. at Asbestos, 40 miles southwest of Thetford, is well along in preparations for caving, and The Bell Asbestos Mines Ltd. at Thetford Mines, will follow their examples later. GERALD SHERMAN, Member AIME, is Consulting Engineer, Johnson's Co. and Canadian Johns-Manville Co., New York, N. Y. AIME San Francisco Meeting, Feb. 1949, and New York Meeting, Feb. 1950. TP 2828 A. Discussion (2 copies) may be sent to Transactions AIME before May 31, 1950. Manuscript received Nov. 2, 1949. Nearly all of the asbestos produced by the western hemisphere is mined in those districts of Canada. Since it has been the subject of a number of technical papers, this contribution is offered as a review of progress. Some introductory information seems appropriate, for few members of the American Institute of Mining and Metallurgical Engineers are familiar with the mineral, or how asbestos deposits differ from others in caving characteristics. Asbestos is found in peridotite, a basic intrusive rock irregularly altered to serpentine and erratically fractured, well enough to cave in bulk, but leaving many blocks of solid ore of all sizes scattered through the deposit. Chrysotile is the variety of asbestos produced in Canada. Its fibers are the most valuable commercially, having a good proportion of long fibers, strong, silky, flexible, and suitable for spinning. The fibers occur in all lengths, from the microscopic to 3 in., or more, the shorter are more abundant. Their values depend on length combined with other qualities noted above. They occur as veinlets filling fissures in the peridotite, with crystals compactly arranged in parallel across the cracks. They are sometimes lightly frozen to the walls but the partings are distinct, often marked by particles of magnetite adhering to the fiber ends. Sometimes they break away from the rock in slabs an inch or more in thickness. In wide fissures the fibers are not always continuous, the "broken fibers" being separated by lines of parting with occasional scattered grains of magnetite, which is an injurious mineral to be elirninated when possible. In addition to the chrysotile ''Cross fiber," some "slip fiber" is found in fault fractures in limited quantities of less valuable character. With the exception of the Asbestos Corp, ore, in which the content is said to be more uniform, asbestos is eccentrically distributed through the peridotite. It is the general impression that the higher grades are more often found in hard rock. There are rich pockets and leaner areas which range down through various grades to minor barren sections. Wholesale mining is necessary to make sure of recovering all the high grade for there are no reliable indications of its existence. Ore selection only appears in constructing assay-grade limits for caving. The mill yield of the Thetford ore body in 1934 was 6 to 10 pct of the ore milled, made up of all classes, with occasional runs up to 15 pct or so. Quotations for Canadian asbestos* are as follows: Per Ton No. 1 Crude (% in. and longer) $896 @ $960 No. 2 Crude (Y8 to % in.) 350 @ 545 Spinning (less than % in.) 204 @ 378 Other classes, price diminishing with length. Shorts or "refuse" 24 @ 46 • From Eng. and Min. Jnl., Nov. 1948. Asbestos of even superior quality for electric insulation is found in Arizona limestone. It is white, containing very little combined iron, but occurs only in small quantities.

Jan 1, 1951

By Gerald Sherman

MINING asbestos ore by caving at Thetford Mines, Quebec, has been described in the Transactions of the Canadian Institute of Mining and Metallurgy in papers presented by the staffs of The Asbestos Corp. Ltd., in 1934, and Johnson's Co. Ltd., in 1941. The production by caving prior to 1949, in round figures, has been 14,500,000 tons of ore by The Asbestos Corp. and 5,500,000 by Johnson's Co. They are the only caving operations in asbestos at the present time. The Jeffrey mine of the Canadian Johns-Manville Co. at Asbestos, 40 miles southwest of Thetford, is well along in preparations for caving, and The Bell Asbestos Mines Ltd. at Thetford Mines, will follow their examples later. GERALD SHERMAN, Member AIME, is Consulting Engineer, Johnson's Co. and Canadian Johns-Manville Co., New York, N. Y. AIME San Francisco Meeting, Feb. 1949, and New York Meeting, Feb. 1950. TP 2828 A. Discussion (2 copies) may be sent to Transactions AIME before May 31, 1950. Manuscript received Nov. 2, 1949. Nearly all of the asbestos produced by the western hemisphere is mined in those districts of Canada. Since it has been the subject of a number of technical papers, this contribution is offered as a review of progress. Some introductory information seems appropriate, for few members of the American Institute of Mining and Metallurgical Engineers are familiar with the mineral, or how asbestos deposits differ from others in caving characteristics. Asbestos is found in peridotite, a basic intrusive rock irregularly altered to serpentine and erratically fractured, well enough to cave in bulk, but leaving many blocks of solid ore of all sizes scattered through the deposit. Chrysotile is the variety of asbestos produced in Canada. Its fibers are the most valuable commercially, having a good proportion of long fibers, strong, silky, flexible, and suitable for spinning. The fibers occur in all lengths, from the microscopic to 3 in., or more, the shorter are more abundant. Their values depend on length combined with other qualities noted above. They occur as veinlets filling fissures in the peridotite, with crystals compactly arranged in parallel across the cracks. They are sometimes lightly frozen to the walls but the partings are distinct, often marked by particles of magnetite adhering to the fiber ends. Sometimes they break away from the rock in slabs an inch or more in thickness. In wide fissures the fibers are not always continuous, the "broken fibers" being separated by lines of parting with occasional scattered grains of magnetite, which is an injurious mineral to be elirninated when possible. In addition to the chrysotile ''Cross fiber," some "slip fiber" is found in fault fractures in limited quantities of less valuable character. With the exception of the Asbestos Corp, ore, in which the content is said to be more uniform, asbestos is eccentrically distributed through the peridotite. It is the general impression that the higher grades are more often found in hard rock. There are rich pockets and leaner areas which range down through various grades to minor barren sections. Wholesale mining is necessary to make sure of recovering all the high grade for there are no reliable indications of its existence. Ore selection only appears in constructing assay-grade limits for caving. The mill yield of the Thetford ore body in 1934 was 6 to 10 pct of the ore milled, made up of all classes, with occasional runs up to 15 pct or so. Quotations for Canadian asbestos* are as follows: Per Ton No. 1 Crude (% in. and longer) $896 @ $960 No. 2 Crude (Y8 to % in.) 350 @ 545 Spinning (less than % in.) 204 @ 378 Other classes, price diminishing with length. Shorts or "refuse" 24 @ 46 • From Eng. and Min. Jnl., Nov. 1948. Asbestos of even superior quality for electric insulation is found in Arizona limestone. It is white, containing very little combined iron, but occurs only in small quantities.

Jan 1, 1951

By FREDERICW K. BRADLE

I HAVE been puzzled by two lines of thought'; one emanating from Washington, D. C., to the effect that we must all cheer up, that in a very short time, measured in terms of months, prices would begin to recover, business would become normal, and prosperity would continue on its way just as before the interruption of a year ago; and a second, coming from certain industrialists and economists, expressing fears that all commodity prices were in for a long downward trend, which would cause much unemployment, eventually drag down wages and so restrict purchasing power as to further aggravate the situation. One basis for the fear of a downward trend in commodity prices' is that ifter great wars a depression could last for something like 40 years-the downward trend to such a depression after our recent World War having been postponed for some reason or other; and the basis for another fear was that the production of gold was becoming less. I had 'also been trying for some time past to refresh my recollection as to how my ow11 particular lead interest climbed out of the depression of 1893; and as all the metals have had, and still have. relative values and prices, I can best express what I have in mind by talking principally about lead.

Jan 1, 1930

By Yoshihiko Maeda

It is said that the 21st century will be an era of the remedy of the global environment. In order to reserve natural resources for the future and to avoid the dispersion of heavy metals after usage and to avoid pollution problems, it is extremely important to recycle heavy metals as much as possible by reasonable recovery procedures. The nonferrous metal industry is expected to play a important role in the recycling of heavy metals that are originally their products. From the depressed metal price experienced in Japan in 1980'h due to the sudden change in current exchange rate between US dollar and Japanese yen, one of major nonferrous metal company, Dowa Mining, has diversified its business area not only to the so-called down stream, but also to the environmental business including metal recycling, industrial waste treatment and soil remediation by utilizing technologis and facilities once used or still used for mining and smelting of copper, zinc, lead and precious metals. In this paper some of these applications will be presented.

Jan 1, 2003

By Yoshihiko Maeda

It is said that the 21 st century will be an era of the remedy of the global environment. In order to reserve natural resources for the future and to avoid the dispersion of heavy metals after usage and to avoid pollution problems, it is extremely important to recycle heavy metals as much as possible by reasonable recovery procedures. The nonferrous metal industry is expected to play a important role in the recycling of heavy metals that are originally their products. From the depressed metal price experienced in Japan in 1980th due to the sudden change in current exchange rate between US dollar and Japanese yen, one of major nonferrous metal company, Dowa Mining, has diversified its business area not only to the so-called down stream, but also to the environmental business including metal recycling, industrial waste treatment and soil remediation by utilizing technologies and facilities once used or still used for mining and smelting of copper, zinc, lead and precious metals. In this paper some of these applications will be presented.

Jan 1, 2003

By Malcolm J. Harrison

The problems associated with the flow control of abrasive slurries and solids laden fluids creates reliability problems in many mining operations. Conventional valves such as pinch, knife gate and plug types cannot always function reliably in such harsh operating environments. Due to the technological advances in the hard coating industry, ball valves can now be produced with internal surfaces protected from the erosive effects of these applications. Pressures well in excess of the capability of conventional 1000 kPa working pressure valves can now be handled reliably. The significant advantages of minimizing down-time and lowering maintenance costs can now be realized with metal seated ball valves.

Jan 1, 1999

By Klaus M. Zeitler

INTRODUCTION One cannot discuss the subject of "Raising Capital in the 1990s" without having a crystal ball and a reliable fortune teller. This discusses "Raising Capital for the 1990sW, which is what Metal1 Mining Corporation did in 1987. We raised (3166 million in an IPO (initial public offering) that was originally planned for only some (375 million. Why did we raise this money? How did we do it, and why was this IPO so successful? The answer to the first question requires a description of the promoter and principal shareholder of Metal1 Mining Corporation, Metallgesellschaft AG. This West Germany company was founded over 100 years ago in Frankfurt as a trading house for non-ferrous metals. It has developed into one of the world's leading firms in the non-ferrous metals industry. The company's worldwide activities in all areas of that business include mining, smelting and refining, the trading of ore, base and precious metals, the production of semi-fabricated and finished metal products, and the provision of engineering, construction and transportation services. Metallgesellschaft AG has also diversified into many other areas, the most significant of which are manufacturing, the production of chemicals, the development and application of technical and chemical processes, the planning and construction of industrial plants, and activities associated with finance, insurance, shipping and freight forwarding, and the provision of barter and countertrade services. The company maintains a network of more than 100 offices around the world; it employs some 25,000 people in its worldwide activities. [Selected financial data, as of September 30, 1987: (MetaUgesellschafl AG) Working Capital DM 8%.6 million CDNS 672.8 million Long Term Debt DM 568.0 million CDNS 426.2 million Sales DM 14.9 billion CDNS 11.2 billion Net Income DM 87.7 million CDN$ 65.8 million Market Capitalization at April 27, 1987: (Metallgesellschafi AG) Outstanding Shares ~,6oo,o0o DM 1,875 million CDNS 1,407 million] For the fiscal year ended September 30, 1987, Metallgesellschaft AG had, on a consolidated basis, net sales of DM13.3 billion, net income of DM100 million and total assets of about DM7.0 billion. Metallgesellschaft AG established the American Metal Company, a predecessor of AMAX Inc. one of the largest ventures undertaken by Metallgesellschaft AG then was the acquisition, through the American Metal Company, of a majority share in the Mexican Penoles mine, a large lead and silver deposit. METALLGESELLSCHAFT AG Figure 1 depicts an overview of Metallgesellschaft AG before and at the time the initial public offering of Metall Mining Corporation's shares took place. It shows that mining was far from the centre of Metallgesellschaft's activities. Therefore, it could not expect to receive an extraordinary amount of board attention. Thus, mining investments not only had to compare well with other mining opportunities, but were in fierce competition with projects from other divisions. In addition, mining was sub-divided into two separate departments -- domestic and international. These two departments had different management styles and diverging interests which resulted in a minimum co-operation between them. The domestic mining department was primarily interested in the survival of the local mines. These mines were characterized by rising operating costs and declining ore grades. It took a special commitment and continued ingenuity to develop and adjust to local conditions, and modern mining and processing technology, in order to remain competitive, or at least survive within the international mining industry. Local management

Jan 1, 1990

By Batric Pesic

Reactions of metallic iron were studied in several different aqueous solution systems: water, medium salt solution used for the growth of T ferrooxidans, ferric iron solution and solution containing T ferrooxidans. Each system was studied under abiotic and biotic conditions in the presence of T ferrooxidans and as a function of pH, particle size of iron powder, temperature, ferrous and ferric iron concentrations. It was found that metallic iron reacts with water differently than does with ferric iron in water. Surprisingly, T ferrooxidans were non-functional in the dissolution of metallic iron. Also, the reactions of metallic iron with pure water were indistinguishable from the reactions with water containing medium salts for bacterial growth. The reactions with ferric iron were also independent of medium culture compounds. The mechanisms of metallic iron reactions with ferric ions are different from the mechanisms of metallic iron reactions with water.

Jan 1, 2001

By R. Scheepers

"Abstract -Mineral deposits and prospects of the Pan African Saldanian orogenic belt in the south­ western Cape Province South Africa, are reviewed. Despite the entire absence of operating base or precious metal mines in the area, this study has established at !east four metal associations that offer enticing exploration potential .The poly-phase deformed, low-grade metamorphosed volcano-sedimentary Malmesbury Group constitutes a complex, poorly understood supracrustal sequence that has been loosely subdivided into the Tygerberg, Swartland and Boland tectono-stratigraphic terranes by northwesterly trending fault zones. Syn- and post-tectonic granitoids of the Cape Granite Suite selectively intruded these terranes. Early S-types preferred the Tygerberg terrane whereas the later I-types dominate the remaining areas. Anorogenic A-type granites, however, occur in all three domains. Known metallization is directly or indirectly related to the intrusives, yet syngenetic deposits are conspicuously absent from the supracrustals. Four metal associations have been identified.•,Cassiterite-wolfrarnite (± Au, Cu, Mo, Fe-sultides) in quartz and quartz/aplite veins hosted by tourmalinized and locally greissenized S-type granite. Similar exo-granitic veins occur in proximal metamorphites.•,Juxtaposed disseminated, stockwork, breccia and vein style Cu-Mo-Fe-(Au)-sultide mineralization hosted by matie to intermediate intrusives of high K calc-alkaline, 1-type affinity.•,Cu-Mo-Au-sultides hosted by hydraulic breccia pipes, stocks and veins occurring in anorogenic A-type alkali feldspar granites and amphibole quartz syenites.•,Scheelite with minor Cu-Mo-sulfides and Au-associated with endo- and exo-skarns spatially related to I-type monzogranite, granite and alkali feldspar granite .The first three associations occur along the Yzerfontein-Helderberg-Zone, a 180 km lineament in the Tygerberg terrane, a zone exploited by syn-, late- and post-tectonic intrusives and their related mineralization. The fourth association is typical of the Boland terrane. The spatial and temporal relationships between the various metal associations is interpreted as the result of sequential intrusion of relative early high level S-type, followed by intermediate level I-type and finally anorogenic A-type granitoids during the evolution of a contracting continental margin arc and its inner arc. This plate tectonic setting suggests subduction in an easterly direction underneath the Kalahari craton. The spatial configuration of the various terranes at the present erosional levels is the result of rifting and significant differential vertical displacement following cessation of subduction, a terminal tectonic event possibly synchronous with intrusion of the A-type granitoids.Near surface preserved roof zones and cupolas of both S- and I-type granitoids in the Tygerberg and Boland terranes, respectively, render these areas extremely prospective for Sn, W, Mo and Au mineralization. The presence of intermediate to mafic volcanics, a diversity of calcareous lithotypes and favorable plate tectonic setting of the Malmesbury Group suggest potential for the thus far elusive VMS, MVT and Sedex base metal and minor precious metal deposits."

Jan 1, 1994

By R Morrison, R Dunn

In many mineral processing operations, the reported production figures for an accounting period may not make the best use of available data. While most of the mathematical approaches, such as check-in/check-out, mass balancing, used in effective metallurgical accounting strategies are well understood, the sources and magnitude of measurement errors generally are not. As part of the æAMIRA P754-Metal Accounting and ReconciliationÆ project, a study was undertaken at the Northparkes copper/gold concentrator near Parkes, New South Wales to examine the data used in their concentrator metallurgical accounting system. This paper summarises the results of a detailed examination of the mass measurement systems around the concentrator as well as the primary sampling system used for grade estimation. The goal of this work was to develop practical techniques to quantify the error (ie both accuracy and precision) of the measured metal accounting information. With this information, statistical confidence levels for this data can then be calculated. If the errors are small, the effect of error in each piece of measured data can then be propagated to other calculated production figures such as recovery and feed grade using a statistical technique called æthe propagation of errorÆ.

Jan 1, 2007

By V. H. Valenzuela

Materials in process or in stocks are quite relevant items in almost every plant, particularly in mining operations, where efficiency in rate of recovering material of interest becomes a key issue when production costs are evaluated. A manager requires information to do an effective use of the resources, especially when raw materials are involved. Losses associated to leaking, efficiency in the transformation process, performance of equipment, and operating conditions are a short list of items which must be properly identified and evaluated. Operations supervisors require information in order to keep key process variables under control. Because of these information needs, it is absolutely necessary to carry on a series of activities related with installation and maintenance of measuring equipment, sampling equipment, sample preparation, chemical analysis, statistical analysis, data handling and reports generation. These pieces of data must be managed on a wise manner in order to get the most of it, keeping always on mind data reliability. Normally, information related with metallurgical balance and even more, the metallurgical balance concept, is handled under an accounting criteria which does not allow dealing with the real world. This situation happens because the criteria utilized do not consider aspects such as bias and uncertainty associated with every measurement that affect the quality of the information and therefore conclusions drawn from it. The purpose of this paper is to give a few rules, necessary to follow, in order to develop an adequate Metallurgical Balance System for an operational point of view. The Gaussian approach for error propagation is used as a basis, allowing one to know the actual uncertainty of the balance and the way how it can be improved. A few real applications of this concept are listed, detailing experiences obtained from practice.

Jan 1, 2007

By I. Baltov

The Chelopech Mine, located in Central Bulgaria, is one of Europe?s largest underground copper- gold mines, currently mines and processes approximately one million tonnes of ore per year. Copper concentrates containing gold and silver with significant arsenic content are produced and sold on the world markets. The operation was acquired by Dundee Precious Metals in 2003. A modernization program for the Mine and Plant has since been in progress to increase both production and mechanical reliability, and also to optimize metallurgical recoveries. Since then, mine output and plant throughput have doubled, plant availabilities and utilization have increased significantly, and overall metallurgical performance for copper and gold improved. The paper presents the systematic approach for obtaining and analyzing data, communicating it, and making suggestions for changes to the technological parameters and flowsheet in order to maximize metal recoveries. These studies have correlated the ore characteristics (particle size distributions, metal assays, and Cu and Au mineralogical and phase analyses) with the actual plant performance (kinetics, recoveries, and throughput). Cu recovery by size has been calculated from the mineralogical analyses of feed, concentrate and tails, with the most significant losses being identified in terms of fraction and phase recoveries. This has provided the recommendations (some of them tested in plant) for changes in the grinding and flotation circuits.

Jan 1, 2014

By E. J. Burrough

Coal Reserves The Crowsnest Pass coal fields form part of a greater area which comprises the Inner Foothills belt of the Alberta coal fields and the southeastern coal fields of British Columbia. The most valuable and most extensive reserves of the bituminous coals of Canada are concentrated in this?area, of which the Crowsnest Pass fields form an important part. The extent of these coal reserves together with those of the rest of Canada were recently studied by the Geological Survey of Canada for the Royal Commission on Coal of 1946 (1). Quotin from the report, it is of interest to note that, prior to this work, the most widely known, and in fact the only Canadian-wide estimates of, coal reserves of Canada available to the Commission were those prepared by Dr. Dowling in 1913 (2). At that time it was estimated that Canada's reserves of coal were over twelve hundred billion tons. The more recent estimates of mineable coal for the whole of Canada are of the order of 10 per cent of that figure and are reported. as 99 billion tons, which is further reduced to 40 billion tons on the basis of the estimation of recoverable coal. This considerable divergence in estimated reserves is explained in part by the big difference in the bases of measurements. For example, in the original report, seams of one foot occurring at a depth of 4,000 feet were included in the estimates.

Jan 1, 1951

The character of alluvial gold deposits presents severe difficulties, and sometimes limitations, on the extent to which metallurgical efficiency can be measured. Very little monitoring of metallurgical performance is practised. An indication of performance is often extracted from the comparison of production to the estimate. This is a dubious practice. The recovery efficiency of conventional practices, viz sluices, tables and jigs, falls off sharply below 0.2 mm. Field evaluation procedures tend to simulate these conventional practices. Thus the presence of fine gold may not be detected, particularly if obscured by clay. There is increasing evidence that fine gold could, in places, be present in sufficient concentrations to be economic. Most gold in paleoplacers is finer than 0.1 mm. There are established practices elsewhere in the mineral industry that may physically recover gold down to 5 microns in size and which could find application for fine alluvial gold.

Jan 1, 1984

By The Staff

Introduction It is the purpose of this paper to discuss a number of the metallurgical improvements in the technology of copper-nickel ore treatment which have been introduced during recent years in the plants of ?the International Nickel Company of Canada, Limited. In common with other ore treatment processes, the procedure for extracting nickel and copper is changing almost continuous! y. These changes are necessitated by reason of changes in ore grades and characteristics, rising material and labour charges, and the constant drive to maximize metal recovery and to minimize production costs. It is not possible to present a comprehensive list of all the changes made, and only a selected number of the improvements in the milling, smelting, and refining operations are covered. It should be clearly understood that some phases of the procedures described have been pioneered by others in kindred fields and due acknowledgment is given to their foresight and efforts. Articles have been published over the years describing the operations of the International Nickel Company plants and the reader is referred to the Engineering and Mining Journal, Vol. 130, No. 9, November 10th, 1930, and to the Canadian Mining Journal, Vol. 58, No. 11, November, 1937, and Vol. 67, No. 5, May, 1946. Other references are the Transactions of this Institute, 1932, 1938, and 1946; Metals Technology, American Institute of Mining and Metallurgical Engineers, February, 1938, and Canadian Chemistry and Process Industries, April, 1940.

Jan 1, 1948

By J Simpson, M Johnston

Recently Mount Isa Mines undertook a study to review the lead-zinc orebodies to extent of resource and reserves and determine the new life-of-mine schedule, as the Mount Isa and Hilton orebodies had not be reviewed for many years. Also, the recovered value of the Mount Isa, Hilton and George Fisher orebodies had been increased by major performance improvements in the lead-zinc concentrator. The Mount Isa Lead-Zinc concentrator processes fine-grained lead-zinc ore from the Mount Isa, Hilton and George Fisher orebodies. These orebodies have varying levels of pyrite and large variation in the grain size and texture of the galena, sphalerite and pyrite. This variation has a large effect on the recovery of the lead and zinc in the concentrator. Some ores achieve 90 per cent recovery at target grades, yet other ores are unable to achieve æsaleableÆ concentrate grade, with no metal being recovered to concentrate and therefore effectively losing the contained metal to the final tailings. Models were created to predict the metallurgical performance of these orebodies, to better reflect the variation that occurs. These improved metallurgical models and economic data allowed the determination of the Net Smelter Return (NSR) for each block in the geological block model. This NSR is the return to MIM of the metals contained in concentrate. The NSR was used as the cut-off grade criteria when determining the value of the ore. This formed the basis of the lead-zinc life-of-mine schedule and the optimisation of the lead-zinc business.

Jan 1, 2003

By M. R. HULL

FOLLOWING the discovery of a body of ore that appears to have commercial possibilities there is a period of development work to determine its extent and grade and the most economical method of mining it. Laboratory tests are made in an effort to determine the most practicable and economical treatment for the extraction of the valuable constituents of the ore and these tests are carried farther and checked in a pilot or test mill. The rate at which the ore is to be mined and the daily capacity of the plants that are to treat it will depend on a number of important factors such as: The size of the orebody; the capital available for building the plants; the market or demand for the final product; the supply of skilled and common labor available for the construction, operation and maintenance of the plants; the quantity and quality of available water, and the amount and cost of power that can be purchased or that can be economically developed. Having decided on the treatment that is to be given to the ore and after full consideration of the above factors the management decides to erect a reduction plant of a given capacity.

Jan 1, 1926

By Mark William Kennedy

Modern metallurgical plants typically have complex flowsheets and operate on a continuous basis. Real time interactions within such processes can be complex and the impacts of streams such as recycles on process efficiency and stability can be highly unexpected prior to actual operation. Current desktop computing power, combined with state-of-the-art flowsheet simulation software like Metsim, allow for thorough analysis of designs to explore the interaction between operating rate, heat and mass balances and in particular the potential negative impact of recycles. Using plant information systems, it is possible to combine real plant data with simple steady state models, using dynamic data exchange links to allow for near real time de-bottlenecking of operations. Accurate analytical results can also be combined with detailed unit operations models to allow for feed-forward model-based-control. This paper will explore some examples of the application of Metsim to real world engineering and plant operational issues.

Jan 1, 2014

By F. W. McQuiston, L. J. Bechaud

3.2-1. Introduction. Much has appeared in the technical literature on theory of sampling (18, 37), weight of sample required in relation to particle size (28), probability of error in sampling (3), and statistical analysis of sample data (20). Each industry, whether it be copper, iron ore, or coal, has its own standards and methods. All of the rather extensive theoretical treatments appearing in published literature on sampling apply to material already on hand such as coal, iron ore, or copper concentrates in rail cars, or in moving streams such as on conveyor belts. The attempt usually is to apply statistical techniques in order to improve reliability and precision in sampling, and to reduce differences between the analyses of seller and buyer. In contrast to this type of sampling, very little has appeared in the literature on sampling a virgin deposit from the metallurgical point of view. Perhaps it would he more descriptive to designate this point of view as "Gm-metallurgical," since geology is inextricably interwoven with metallurgy in gaining an understanding of the complexities of a deposit, eventually leading to a definition of mineable reserves, with the development of a flowsheet and engineering criteria for the planning of a successful and profitable operation. The degree of cooperation between these two departments often determines whether the processing plant is a success at the inception of operations, or whether expensive changes and modifications must he made, with the plant finally reaching rated capacity at some later date. The first concern of the metallurgical department should be to establish proper accreditation of the samples which will be used in any ore-testing campaign. It should he made mandatory, as part of operating management policy, for the responsible metallurgist to he aware of the significance of the samples and to become intimately knowledgeable in all aspects of metallurgical behavior and response to treatment of all varieties of ore in the deposit under consideration.

Jan 1, 1968