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By W. R. Hopkins, J. A. Davis

"This paper presents a discussion of the mechanisms by which aerosols of the process electrolyte are entrained into the breathing environment of copper, Zinc and nickel eIectrowinning tankhouses. Literature outlining the health effects associated with worker & posure to the acidic and metallic contaminants found in the airbome aerosols is summarized and compared with existing North American regulations.A brief review of the existing technologies for the source reduction of these aerosols is presented. This paper outlines the industry experience with use of covers, balls, beads, shapes, fixtures and chemical surfaetants. Each of these devices is ranked according to its effusiveness in the process in which it is used, and rated according to its operator acceptance.The various forms of existing in-plant ventilation systems are reviewed with a discussion of their relative merits and effectiveness. Actual experience is related, detailing the methods of testing for ambient contaminant levels in a variety of tankhouse environments. Guidelines are provided for the site and process specific criteria which govern the selection and ultimate effectiveness of a particular form of ventilation system.Finally, actual project experience is cited in which hydraulic modelling is used a design tool in tankhouse ventilation design. These projects include the upgrading of existing traditional ventilation designs, and the ''grass roots"" design of a more efficient aerosol source control system to be used in high altitude, cold weather sites."

Jan 1, 1994

By Donald R. East

For many years there has been increasing pressure on mining companies, not without some justification, to design tailings storage facilities which guarantee some degree of protection against process solutions entering local groundwater and surface water flows. A fairly straightforward approach to achieving this has been to design conventional water-retaining type structures, and this has often been reinforced by the need to store large volumes of process water and seasonal run-off within the tailings facility. The conventional design uses naturally occurring geological barriers and a conventional embankment with possibly a grout curtain, or artificial barriers around the entire facility, using either imported low permeability soils, admixtures, or synthetic liners. While these approaches may achieve the primary objective of minimizing seepage, various other factors should be considered. Firstly, by depositing the tailings slurry in a sub-aqueous manner, the tailings, especially if relatively fine grained, will settle to very low densities and little or no on-going consolidation may occur over the operating life of the mine, There have been many cases where measured pore pressures within the tailings mass equal the total overburden stress, i.e., no consolidation and no strength, many years after decommissioning.

Jan 1, 1998

By E. Bélisle, Christopher W. Bale, S. Petersen, C. Robelin, K. Hack, J. Melançon, G. Eriksson, A. D. Pelton, P. Chartrand, S. A. Decterov, I. H. Jung, A. Gheribi

The FactSage® package consists of a series of information, database and calculation modules that enable one to access pure substances and solution databases and perform thermochemical equilibrium calculations. FactSage was originally founded by process pyrometallurgists and has since expanded its applications to include hydrometallurgy, electrometallurgy, corrosion, glass technology, combustion, ceramics, geology, environmental studies, etc. With the various modules one can perform a wide variety of thermochemical calculations and generate tables and graphs of complex chemical equilibria and phase diagrams for multicomponent systems. This paper presents examples of recent and current developments in FactSage in areas of particular interest to Dr. David Robertson. These include both ferrous and non-ferrous processing, as well as solidification and refining simulation. The paper also includes reference to the Internet Fact-Web education package.

Jan 1, 2014

By C. N. Bensley, S. K. Nicol

The major developments in fine coal processing in Australia are reviewed. Emphasis is placed on the approaches taken by various Australian coal producers to improve the recovery of the coarse size fractions (minus 0.5 plus 0.25mm) and upgrade the selectivity of flotation at ultrafine sizes (minus 0.075mm). The effects on fine coal preparation of flotation circuit changes, the influence of physical and chemical variables on coarse coal flotation and the impact of spiral concentrators and column flotation, are discussed. Reference is also made to the development of oil agglomeration technology for the treatment of fine coal refuse and some of the factors which have led to its current demise.

Jan 1, 1988

By S Sondashi, F. J. Chidley, W. A. Grobler

Some of the challenges facing the flotation of base metal sulphides are the opening of new and varying ore bodies as well as maintaining essential skills in plants. Flotation reagent research focuses not only on improving flotation grade and recovery, but also on producing reagents robust enough to cope with changes. A group of recently developed co-collectors, activators, depressants and frothers are described together with a summary of results measured on base metal sulphide ores.

Jan 1, 2005

By I. Weir-Jones

[Currently the cost of carrying out 'in situ' geotechnical investigation programmes or installing and operating monitoring systems at construction or mining sites is rising var." rapidly. This is primarily because of our ever increasing labour rates. As a result of this problem efforts are no,, being made develop techniques for the economical; collection of large quantities of geotechnical data relating, to such problems as done stability evaluation, the behaviour of underground openings, or 'in situ' testing procedures. The efforts to reduce the labour content. are particularly apparent in those procedures which have traditionally been manpower intensive e.g. 'in situ' permeability testing where an entire drilling crew and their associated eguipment have been on standby while testis has been carried out; or data collection in underground construction operations where much tine is typically wasted obtaining or maintaining access to instrument sites. In an attempt to illustrate one specialist consulting company's approach to the problem of reducing investigation costs, this rarer examines four recent developments in the field of geotechnical investigation and monitoring which have come about during the last two Years as a result of cur research and development programme. Although these techniques and devices have been developed for specific projects, they all have broad applications in the geotechnical field and they are indicative of the direction in which this company feels developments will take place.]

Jan 1, 1975

By Simon P. Fricker

Gold drugs have been used for the treatment of rheumatoid arthritis since the mid 20th century as disease-modifying antirheumatic drugs (DMARD) class. Methotrexate is often the preferred DMARD, and with the advent of new therapies gold drugs are now used infrequently. Since the introduction of auranofin in 1985 there has been no new clinically approved gold drug. In spite of this apparent lack of progress there has been a great deal of interest in the use of gold compounds for cancer therapy and early promising indications were achieved with a gold phosphine complex [Au(dppe)2]Cl. This compound was not entered for clinical trials, however, due to problems with cardiotoxicity highlighted during pre-clinical toxicology studies. Gold(III) is isoelectronic (d8) with platinum(II) and likewise forms square planar complexes. It is therefore tempting to speculate that such complexes would have similar antitumor activity to cisplatin. In order to stabilise the gold(III) oxidation cycloaurated complexes were synthesised with a single mononegative bidentate ligand, damp, (2-[(dimethylamino)methyl]phenyl), and two monodentate anionic ligands e.g. Cl or acetate. The damp ligand forms part of a five-membered chelate ring. The monodentate ligands are readily hydrolysed and are available for substitution. These compounds had limited anti-tumor activity in in vivo against human tumor xenografts. Mechanistic studies indicated that these compounds had a different mechanism of action to cisplatin. An alternative molecular target for these compounds is biologically important thiol-containing molecules such as the cysteine protease cathepsin B. Modifications were made to the Au(III) damp structure to give compounds with a six-membered chelate ring. These compounds were shown to be inhibitors of cathepsin B. Compounds were also tested for cytotoxicity against a panel of human tumor cell lines. Three compounds were selected for further evaluation against a human colon tumor xenograft. The compounds showed modest anti-tumor activity but with no marked improvement over the parent Au(III)damp complexes. Initial indications are that Au(III) compounds targeted against disease-specific thiol-containing biological molecules have potential as drugs, particularly for cancer. However, further work is required to produce a target-specific drug with a suitable pharmacological activity and toxicity profile.

Oct 1, 2003

Recent and on-going studies on the leaching of gold, the properties and activity of carbon, developments in the elution of gold from carbon, and methods of recovering gold from solution are reviewed. Emphasis is placed on Australian contributions, and their impact on gold metallurgy. Consideration is given to the future development of selective solvent extractants, ion exchange resins or alternative reagents for cyanide.

Jan 1, 1987

By W. B. Timm

Introduction In preparing this paper on Recent Developments in Gold Milling Practice, the idea occurred to me that possibly the best way to deal with the subject would be to take you in thought on a visit to the principal gold mining camps of the Dominion, starting at the east and finishing up in the west, and noting, as we go, the outstanding improvements that have been made in the last few years in the practice of gold milling. Before beginning this tour, I desire to emphasize the debt this country, and particularly our mining industry, owes to that body of trained and experienced men, little heard of, but who, working quietly on their problems, are responsible for these improvements. The metallurgists, to whom I refer, have solved many difficult problems for the mining industry, in connection with the treatment of our complex ores; for instance, the silver-cobalt ores of the Cobalt district, the gold ores of the Porcupine district, the gold-telluride ores of the Kirkland Lake? district, the copper-gold ores of Noranda, the arsenical-gold ores of the Beattie mine, the copper-zinc ores of Flin Flon, and the lead-zinc ores of Kimberley. In doing so, they have maintained the high technical standards of the profession, and the practices thus evolved are noteworthy for their high degree of efficiency. When the price of gold increased from $20.67 to $35.00 an ounce, what had formerly been thought to be a low tailing became almost an ore, so that the metallurgists are now busily engaged upon the problem of putting this railing back in its proper place of being a tailing once more, or from its value, at the present price, of anywhere from 50 cents to a dollar or so per ton, to a few cents per ton. Owing to the changing prices of the metals in the world's markets, still greater improvements in metallurgical practices are imperative. An important contributory factor towards improvement in ore dressing is the aid furnished by the microscope in the examination of ores and mill products. By making possible the determination of the mineral constituents of the ore, their association, and grain size, it gives the investigator a knowledge of his problem, before he does any actual test work. In the Mines Branch laboratories at Ottawa, its use has enabled us to predict how an ore should respond to various methods of treatment.

Jan 1, 1935

By G. Belardi, N. Sheau, P. Plescia, F. Veglio

A study was conducted to assess a new wet gravity-separation machine, identified as the Multi-Gravity Separator(MGS). Chromite fines, obained from an Albanian chromite and olivine ore and containing 23% Cr2O3 and 18% SiO2, were used in the study. The first step was to determine the influence of various operating parameters. The study indicated that the most important variables for the MGS are rotational speed, tilt angle and shake amplitude. The best treatment conditions for the ore were then identified by investigating a series of circuits designed to produce a marketable product. In open circuit, a concentrate containing 50% CI-203 was obtained with a recovery of 72%.

Jan 1, 1996

By John V. Beall

HEAVY-DENSITY separation processes, a commercial application of the sink-float test used in mineralogical laboratories for the separation of mineral particles by their difference in specific gravity, are the biggest development in mineral dressing since flotation, which was at about the same stage of development thirty years ago. The scope of their application has broadened and, though still in the development stage, they are being accepted in a constantly increasing number of commercial installations. This progress in mineral beneficiation is especially satisfying when we realize that our high-grade ore deposits are fast disappearing and a big factor in determining whether a hole in the ground is being sat upon by a liar or an honest citizen is how economically the ore dressers can concentrate comparatively low-grade ores. As early as the middle of the nineteenth century attempts were made to use aqueous salt solutions in a heavy-liquid separation for cleaning coal. But the original and recovery costs of these liquids were high and further, the fact that they were corrosive, unstable, and toxic added to the difficulty in using them.

Jan 1, 1948

By Fengnian Shi

In the current energy-sensitive world, sustainable development in the mineral industry will require new, better and more efficient processes. Novel comminution methods, which offer the prospect of achieving the required outcomes of size reduction and mineral liberation at lower energy consumption, are continually being sought. In the past five years, extensive research using high voltage pulse electrical comminution technology has been carried out at the Julius Kruttschnitt Mineral Research Centre (JKMRC), in collaboration with selFrag AG. The major outcome of this research is the development of the concept of pre-weakening ore particles by electrical comminution procedures to reduce the energy consumption in the downstream grinding circuit. The research has also verified the preferential liberation of valuable minerals by electrical comminution. Given the advantages, several potential applications of electrical comminution in the mineral industry are proposed, including AG/SAG mill feed pre-weakening, pebble treatment, ball mill feed pre-weakening, early recovery of the liberated valuable minerals, crack/micro crack generation for improved leaching, and smelter slag treatment. For the mineral industry to utilize electrical comminution, two emerging issues identified from the research need to be address. They are the energy consumption by electrical comminution in the locked cycle treatment and the facilities scale up necessary to move this technology from the laboratory to the plant. Keywords: high voltage pulses, electrical comminution, energy efficiency, mineral liberation

Sep 1, 2012

By George K. Schenck

INTRODUCTION Recent advances in high-pressure water jet technology can be effectively employed in mining and tunneling. The new equipment is based on available industrial hardware such as pumps, nozzles, and rotary swivels and seals, and is compatible with present mining and tunneling techniques. Principal advantages of water-jet assisted cutting relative to standard cutting are higher production rates, lower dust levels, and reduced fines. When used on rock and coal miners, water jets mean that relatively smaller and cheaper machines can be purchased. If properly applied, the combined effect is lower cost and significantly improved health and safety. While commercial use of high-pressure water blast cutting and extraction of rock (and concrete) already has a firm foothold in Europe, application of this new technique is just beginning in America. This paper begins with current American applications of high-pressure water jets for drills, for slotting and channeling machines, and then discusses the emerging technology for initiating rock failure in conjunction with drag bits on coal plows, continuous miners and boom-type miners (roadheaders). The focus of this paper is use of high-pressure water jets for cutting rock. High-pressure water jet cutting utilizes water above 70 MPa and currently reaches to 300 MPa and above. Some informatfon is included on low pressure "wethead" coal shearers and boom miners with water pressure to about 15 MPa.

Jan 1, 1983

By K. M. Tait, M. M. McDonald

"An overview of the status of the development and application of Integrated Gasification Combined Cycle (IOCC) power generation is presented. Current projects in North America, Europe and Japan are described, together with the status of plans to apply the technology in Canada. A brief review of the technology is presented, including promising coproduction cycles and hybrid gasification fluid bed processes. The ability of the process to be modified for CO2 to be extracted for enhanced oil recovery or disposal is addressed. The environmental impact of IGCC technology is compared to those of other power generation technologies IntroductionDefinition and HistoryIntegrated Gasification Combined Cycle (IGCC) technology is a concept which has been around for about 50 years but has been generating increasing interest in the last 10 to 15 years. This paper focusses on coal as the feedstock for gasification. Other feedstocks used in gasification systems have included oil, biomass, tires and petroleum coke. IGCC technology integrates coal gasification with generation of electricity by means of a combined cycle system which fires the produced gas in the gas turbine. Figure 1 shows the basic components of an IGCC system which are the gasifier, the gas cleanup system and sulphur recovery plant, the gas turbine/generator set, the heat recovery steam generator (HRSG) and the steam turbine/generator set. The benefits of an IGCC system over a conventional Rankine Cycle pulverized coal (RCPC) fired system for the generation of electricity from coal are that the IGCC system has potential to have higher efficiency and lower emissions of NO., SO and CO2 per unit of power produced than the corresponding RCPC system."

Jan 1, 1994

"Injection technology has been an important subject from the early days of ladle metallurgy until the present. During the last decade, there have not been many publications in the area of injection technology. It is the author's opinion that with the challenge to find new solutions especially to environmental and energy related problems as well as better understanding of phenomenas from computer modelling, a new era of inventive injection technology developments is at hand. This is illustrated in the article with examples from six different areas where MEFOS is or have recently carried out R&D work related to issues from the injection technology field. IntroductionThe boom in injection technologies came with the introduction of ladle metallurgy treatment during the '70s and '80s. Since then, the theories and principles have been thoroughly laid down by a number of scientists and also published at several early SCANINJECT conferences.Not many new technologies/applications have been presented during the last ten years. This might lead one to believe that everything is known and done. Those, like MEFOS, who are challenged to find technological solutions to a number of environmental problems and energy saving issues in the pyrometallurgical field are, however, continuously faced with the task of developing new injection technologies.Especially, the call for sustainable technologies to solve environmental problems is a challenge for metallurgists all over the world and it will surely induce a revival of injection technologies. So, in order to encourage all injection experts, let us share some new experiences and let us encourage each other's creativity to solve some of the demands of the future society.The following show some examples of technologies under development, or recently tested."

Jan 1, 1996

By T. R. Ellis

A number of important international events took place in 2001 in the development and evolution of mineral valuation standards internationally. In Canada, the CIMVal Committee released a draft discussion paper for public and industry comment on principles to guide the development of the planned Canadian mineral-property valuation standard. The International Accounting Standards Board (IASB) received comments on its Extractive Industries Issues Paper. IASB will decide whether the financial statements of public mining and petroleum companies will be allowed to provide the value of mineral and petroleum assets on a current value basis instead of an historic cost basis. The author led the Extractive Industries Task Force of the International Valuation Standards Committee (IVSC) in developing its submission to IASB. IVSC intends to develop an extractive-industries valuation section for its International Valuation Standards, which could support the planned IASB standard. In Australia, AusIMM has carried out an in-depth review of its highly regarded VALMIN Code. The AusIMM's MICA subdivision organized the VALMIN `01 Conference in Sydney, Australia, with a range of international and current issues papers published in the VALMIN '01 book. Considerable support for the IVSC initiative was evident at this conference. The results of the review of the extractive industries submissions to the IASB were expected to be released in early 2002. The CMMI Congress in Cairns, Australia in May 2002 is likely to prove to be an important forum for continued discussion of the development and implementation of international standards and qualifications for mineral valuation. The outcomes and implications of these events are discussed.

Jan 1, 2003

By T. R. Ellis

A number of important international events took place in 2001 in the development and evolution of mineral valuation standards internationally. In Canada, the CIMVal Committee released a draft discussion paper for public and industry comment on principles to guide the development of the planned Canadian mineral property valuation standard. The International Accounting Standards Board (IASB) received comments on its Extractive Industries Issues Paper. IASB will decide whether the financial statements of public mining and petroleum companies will be allowed to provide the value of mineral and petroleum assets on a current value basis instead of an historic cost basis. The author led the Extractive Industries Task Force of the International Valuation Standards Committee (IVSC) in developing its submission to IASB. IVSC intends to develop an extractive industries valuation section for its International Valuation Standards, which could support the planned IASB standard. In Australia, AusIMM has carried out an in-depth review of its highly regarded VALMIN Code. The AusIMM's MICA subdivision organized the VALMIN ‘01 Conference in Sydney, Australia, with a range of international and current issues papers published in the VALMIN ‘01 book. Considerable support for the IVSC initiative was evident at this conference. The results of the review of the extractive industries submissions to the IASB are expected to be released in early 2002. The CMMI Congress in Cairns, Australia in May 2002 is likely to prove to be an important forum for continued discussion of the development and implementation of international standards and qualifications for mineral valuation. The outcomes and implications of these events are discussed.

Jan 1, 2002

By Claassen J. O.

The Zinc Corporation of South Africa Ltd. (Zincor) operates an integrated roast ? leach ? electrowinning circuit. The efficient removal and control of iron forms an integral part of the process. Zincor developed its own iron removal process (Zincor Process), which was recently shown to be unique with some similarities to the para-goethite iron removal process. Newly developed operating parameters for iron removal are in the process of being implemented. These include a change in the pH-profile and operating temperature, the recycling of seed material and the utilisation of an alternative neutralising agent to aid iron removal. Some of these actions, together with the implementation of a pre-neutralisation step, new filtration equipment and control systems in Zincor?s Residue Treatment Plant have significantly reduced zinc losses associated with iron in calcine and the iron residue produced. This enabled Zincor to take a step closer to world-class zinc recovery levels of around 96% for a similar type of operation.

Jan 1, 2003

By W. M. Armstrong

THE GROWTH of the major iron and steel industries on this continent and in many European countries was based on the use of as-mined, high-grade, lump iron ores and on the availability of metallurgical coking coals. The modern coke-fired blast furnace was developed for such materials and is one of the most efficient of ail pyrometallurgical processes. Most of the impure pig iron produced by blast furnaces was converted to refined steel by the Bessemer process in the years prior to 1900 but, when large quantities of low-cost steel scrap be-came available, the more flexible open hearth process was adopted by most large steel producers on this continent. Although this pro-cess has many desirable metallurgical features, the thermal efficiency is low, the capital cost is very high, and the method of charging scrap steel is inefficient by modern standards of material handling. In recent years several conditions have arisen which have stimulated the development of many new pro-cesses and the re-examination of the existing smelting and steelmaking techniques.

Jan 1, 1958

By O. P. Chisholm

The most noticeable change in lead smelting over the past few years has been the increase in the smelting rate of lead blast furnaces. For several years a great deal of attention has been paid to the preparation of the blast-furnace sinter charge but more recently the plan has been to incorporate- almost the entire makeup of the blast-furnace charge, excepting coke and scrap iron, at the sintering machines. Formerly, sintering machines were used primarily for removing, sulphur and for agglomerating finely divided material both sulphide and oxide in character. Limestone flux usually was so proportioned that a relatively large amount was added to the furnace charge direct. This procedure was also followed with oxidized ores, which were purposely crushed coarse' so that they would be adaptable for direct smelting on the furnace charge. In later years it has been the tendency in western smelters to include practically all of the limestone and oxidized ores in the sinter charge. This has been somewhat more costly because fine crushing is required for sintering purposes and because these oxidized materials were given additional processing through the sinter plant. The addition of such oxidized materials to the usual charge to be sintered, brought about, in certain instances, a deficiency in heat ordinarily supplied by the sulphide constituents of the charge. This heat deficiency has been remedied by the addition of carbonaceous fuel, in the form of finely crushed coke breeze, or in a few instances by the addition of zinc retort-plant residues. The enhanced gold price has stimulated the mining of crude siliceous ores throughout the Western States and in the smelting of such ores more limestone is required for fluxing. Shipments of gold-bearing pyritic concentrates to Western smelters have increased, and the combination of increased silica, limestone and pyrite has increased the percentage of slag, which, in itself, is an aid in .securing smoother and more rapid smelting in the blast furnace. By the addition of these substances, the percentage of zinc in the slag has been appreciably lowered. at many plants, with resultant benefit to smelting speed at the blast furnace. This increase in slag formation with lowered zinc content has caused also perceptible lessening of the amount of lead on the charge and this has benefited the blast-furnace smelting. Although a satisfactory sinter is fundamental in increased rate of bullion production per furnace, there has been a trend over the list four or five years to decrease the percentage of coke and increase the percentage of scrap iron and limestone on the blast-furnace charge. As a result of these changes in practice certain blast furnaces, without any mechanical change, have doubled or tripled their tonnages. For furnaces whore the volume of air is recorded, records show decidedly larger air volumes with a comparatively small increase in air, pressure, or, none at all.

Jan 1, 1941