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An extensive study was carried out to evaluate the performance of Outokumpu OK50, OK38 and Maxwell MX14 cells at ComincoÆs Red Dog flotation concentrator in Alaska. Tests were conducted by varying operating conditions of the cells installed in different circuits in the plant. The hydrodynamic and gas dispersion properties were measured and the metallurgical performance of the cells was evaluated for each condition used in the tests. This paper highlights the importance of superficial gas velocity, bubble surface area flux, gas hold-up, power consumption, residence time distribution and froth flow behaviour in optimising cell performance. The findings of these tests provide valuable insights into selection of the best cell operating conditions to optimise circuit performance.

Jan 1, 2000

The primary purpose of the Institute is to advance the technologic and engineering arts embraced by it through interchange of knowledge. This can best be done by the presentation and discussion of technical papers by its members. Short practical papers are especially welcome. An author should always satisfy himself that his material is of a quality that will be a credit to him and to the Institute. The preparation of a good paper frequently leads to a reorientation of the author's thoughts, and publication contributes much to the professional standing of the author. Members are urged to submit papers presenting the results of their work. Attention to the following suggestions will greatly further the prompt and efficient handling of manuscripts.

Jan 1, 1944

The primary purpose of the Institute is to advance the technologic and engineering arts embraced by it through inter- change of knowledge. This can best be done by the presentation and discussion of technical papers by its members. Short practical papers are especially welcome. An author should always satisfy himself that his material is of a quality that will be a credit to him and to the Institute. The preparation of a good paper frequently leads to a reorientation of the author's thoughts, and publication contributes much to the professional standing of the author. Members are urged to submit papers presenting the results of their work. Attention to the following suggestions will greatly further the prompt and efficient handling of manuscripts.

Jan 1, 1946

By Jack Fox

Although this is going to appear in the December Issue of &E, it is being written long before the end of the year. December, of course, is the time for a summing up of the year's activities. Perhaps, the best way to begin is to report on what went on at the SME Board of Directors Meeting in St. Louis on October 20. This won't be a chronological report, and I shall take time to comment on some of the items we cover as we go along. You should be encouraged to know that your Directors take their duties seriously. Of the 21 current Directors, 19 were present, and three of the new 1971 Directors came to observe what goes on at an SME Board Meeting.

Jan 1, 1970

By Bruce A. Kennedy

The place of the young engineer in the mining industry has been the subject of a large number of keynote addresses, magazine articles, and papers in the past year. One of the best of these was the keynote address given by Mr. J. C. Kinnear, Jr. at the Fifth Annual Intermountain Minerals Conference in Vail. Colorado. Mr. Kinnear presented as part of his address the statistics of a Canadian survey Instigated to find out why young engineers and geologists are leaving the mining industry. The results of the survey showed four main reasons for leaving: 1) insufficient money 2) slow promotion 3) lack of association with senior engineers, as well as insufficient opportunity to keep abreast of technological development 4) geographic isolation

Jan 1, 1970

By M. S. Klima, P. T. Luckie

An evaluation of the operating performance of a recently designed pneumatic centrifugal classifier is presented. This classifier has been modified from a separate air and feed input design to an entrained solids in air feed input. The evaluation first required determining the size distributions for the three streams (feed, fine, and coarse). Using size distribution data and mass flow rates, a size selectivity curve was calculated for each operating condition tested. This curve, in turn, was characterized by appropriate selectivity parameters (i.e., the equiprobable or cut size, the sharpness index, and the apparent bypass values). The variation of these parameters with classifier operating conditions was examined. From these evaluations, the "best" operating conditions for the classifier were then determined.

Jan 1, 1985

By John V. Beall

As Mother Nature arranged it, the hottest potential mineral target in the country today, the Stillwater complex had to occur in a spectacular natural setting-the north margin of the Bear Tooth Mountains of Montana. What more appropriate backdrop for the August 17-18 field hearings of Senator Frank E. Moss (D-Utah). His subcommittee, on Minerals. Materials and Fuels, heard 37 witnesses ponder the value of minerals vs esthetics or other uses of federal lands. On August 17, four Army Hueys swept the senatorial party, the press, Forest Service Officers and such distinguished witnesses as Montana Governor Forrest H. Anderson over the Custer-Gallatin National Forests, besting the thin air of 10,000 ft p1us, they set down on Iron Plateau.

Jan 1, 1971

By Jeffrey C. Reid

Computer processing and high resolution graphics display of geochemical data were used to quickly, accurately, and efficiently obtain impor¬tant decision-making information for tin (cassiterite) exploration, Seward Peninsula, Alaska (USA). Primary geochemical dispersion patterns were determined for tin-bearing intrusive granite phases of Late Cretaceous age with exploration bedrock lithogeochemistry at the Kougarok tin prospect. Expensive diamond drilling footage was required to reach exploration objectives. Recogni¬tion of element distribution and dispersion patterns was useful in subsurface interpretation and correla¬tion, and to aid location of other holes. Tin was its own best pathfinder. Arsenic, also a useful pathfinder element, forms a discrete halo peripheral to tin mineralization. The arsenic halo is expressed in hand specimens by asenopyrite and/or scorodite staining.

Jan 1, 1989

By Christopher Haycocks, J. Richard Lucas

The growth of computer and ground control technology in recent years, combined with an urgent demand for low-cost fossil fuels and mineral resources, has set the stage for full-scale utilization of computers in mine planning. Steeply rising production costs and the need to preserve the environment are placing great demands on engineers to improve their mining efficiencies, which can best be accomplished by applying the full capabilities of the computer. Pressure to develop and perfect programs with an immediate potential for improving mine design, reducing mining costs and extending the viable coal reserves of the country has already come to bear in the form of exploding energy requirements, environmental considerations and the visible limitations of other energy sources.

Jan 4, 1973

By G. Knight

It is shown that the dust exposure of all underground workers varies greatly from day to day even though each man did the same job in the same working place each day. The variability follows a logarithmic normal distribution with a geometric standard deviation of about 1.6 for the three dust assessments; total respirable dust, respirable combustible dust and respirable quartz dust in both mines studied. The variability was homogeneous for all men and most jobs. The differences between men doing the same job was found not to be significant and it is suggested that the dust sampling program should determine the average for each job and use this as the best estimate of the exposure for each man.

Jan 1, 1980

By Thomas L. McVay

The Bureau of Mines made laboratory batch and small-scale continuous flotation tests of a sample of pegmatite rock from a deposit of the Lithium Corporation of America, Inc., near Kings Mountain, N.C., to determine the feasibility of producing commercial-grade spodumene concentrates. Various reagents and flotation procedures were tested to determine the optimum conditions for floating the spodumene and retarding the gangue minerals. The best results were obtained when sodium fluoride and lignin sulfonate were used as the pulp conditioner and oleic acid was used as the spodumene collector. The continuous flotation tests indicated that commercial-grade. spodumene concentrates analyzing 6.4 pct. Li2O could be produced with recovery of 77 pct. of the lithia in the ore.

Jan 1, 1962

By Dorricott M. G, McAllister J

This paper is concerned with the application of a probabilistic approach to the risk assessment of mining projects.In current practice, sensitivity analysis is the most commonly used deterministic approach of accounting for the uncertainties involved in mining project evaluation, while Monte Carlo simulation is considered to be the best probabilistic method available for the same purpose. The methodology of the approach proposed in this paper is as simple as that of sensitivity analysis. However, the results obtained can be more comprehensive than those obtained from Monte Carlo simulation. Various important statistical features, such as correlation and skewness, of the basic random parameters can be easily taken into account by the proposed approach. Example studies are demonstrated. Lotus 123 was employed for the associated probabilistic calculations.

Jan 1, 1992

By M. Li, J. D. Miller

It has been discovered that water insoluble alcoholic solutions of alkyl hydroxamic acids serve as selective collectors for the flotation of phosphate mineral resources (Miller et al., 2000). The effectiveness of the new collector chemistry has been demonstrated by the results from single stage bench scale flotation experiments for feed material from plants in Florida, North Carolina, and Utah. In the best case, from experiments with low grade (5% P20,) coarse feed (16 x 35 mesh), a single stage phosphate recovery of 95% was achieved with a concentrate grade of 31% P20,. Such a separation efficiency could not be achieved using the traditional fatty acid/fuel oil collectors as is evident from a comparison of the respective grade/recovery curves.

Jan 1, 2002

By Chinmoy Sarkar

Mining organizations have been trying to employ best practices at exploration, exploitation and processing level to increase productivity in the supply chain. Traditional techniques of cost control can no longer meet the ambitious target of mine managers. An integrated perspective of Mining Value Chain with enterprise-wide application of information technology (IT) ensures the ability of every mining processes to improve energy, land, capital and labour resource performance while continuing to cut costs and achieve profitability. IT offers enormous potential in mining industry at shaping entirely new opportunities to create value. This paper characterizes important entities of Mining Value Chain and attempts to provide a vision on how IT can transform the mindsets of industry managers addressing the needs of the customers.

Jan 1, 2002

By I. J. Corrans

Wet high-intensity magnetic separation (WHIMS) has been successfully applied to the recovery of gold and uranium from the residues of Witwatersrand ores. Good overall recoveries have been achieved for particles as small as 12µ, and finer particles of uranium minerals are recovered when present as inclusions. The best results were obtained with a matrix of soft-iron balls 6 mm in diameter. However, pilot-plant tests drew attention to a major defect of the machine: the matrix could be blocked by wood chips and ferromagnetic particles. This problem was overcome by the incorporation of a modification that allows the balls to be discharged from the rotating annulus. Two full-scale units that incorporate the modification have been installed.

Jan 1, 1980

By D. W. Duncan, A. Bruynesteyn

An ore containing chalcopyrite was microbiologically leached in 6 ft columns at particle sizes ranging from -2 +1 ½ inches, to -3/8 + 3/16 inches. The rate of leaching increased exponentially as the particle size decreased. The controlling factor was the active leaching volume made up of the particle surface area and the depth of penetration of the bacteria and leach liquor into the particle. This volume became an increasingly larger part of the total volume as the particle size decreased. The sample under test leached poorly at larger particle sizes and it was calculated that under commercial conditions, it would produce at best a pregnant solution containing 100 mg/l (0.2 lb/ ton) of copper per 100 ft of dump height.

Jan 1, 1974

By M. Hawker, M. Kreuh

The mining and metallurgy industry is known to be of cyclical nature associated with price volatility. As such, some years are quite lucrative and other years require mining companies to tighten their belts. The field is a mix of junior, mid-tier, and major mining companies. One thing that is common to all of them is the time required and the cost to develop a flowsheet in accordance with best practices. Although a long list of factors can impact flowsheet development, this paper will include the impacts of: experienced metallurgical engineers and laboratories, representative samples for high quality and valuable testwork results, and following engineering development stages. The paper also provides typical time frames to complete selected engineering flowsheet development steps.

Jan 1, 2014

By V. Srajer

This paper deals with the problem of efficiently selecting the most appropriate loading and hauling equipment for surface mines. Problems and factors that affect productivity and operating cost are identified. During the course of collecting the information for this study, mining companies and equipment manufacturers were interviewed to define their selection practices. The majority of mining companies prepare general specifications and ask the suppliers to mate those specifications to their product line. The mining company then evaluates various proposals on the basis of the best available deal. The following 'mines from western Canada provided information for this study: Coal Mountain, Line Creek, Quintette, Westar's Harmer mine from the Province of British Columbia, and Coal Valley, Gregg River, Highvale, Luscar from the Province of Alberta.

Jan 1, 1989

By D. D. Harbuck

The U.S. Bureau of Mines recently identified a significant new source of scandium in an Oklahoma tantalum waste residue (approximately 0.24 pct Sc). Because scandium is a strategic and critical metal which the Department of Defense has classified for special consideration, the Bureau is researching methods of recovering scandium and associated metals from this and other process residues. A variety of operating parameters were evaluated to determine the best technique for recovering scandium. Testing showed that by sulfating the residue at temperatures as low as 150' C for reaction times as short as 0.5 hr, over 94 pct of the scandium converted to a water soluble form. Solvent extraction using DEHPA selectively recovered 100 pct of the scandium from the water leach solution.

Jan 1, 1992

By Marina Nicolova, Irena Spasova, Plamen Georgiev, Stoyan Groudev

Different strains of "silicate" bacteria were used to improve the quality of kaolin by different ways of treatment. All strains formed large slimy capsules consisting of exopolysaccharides and were related to different species of the genus Bacillus, mainly to B. circulans and B. mucilaginosus. It was found that even a short contact of some hours of well developed cultures of these bacteria resulted in improvement of the bending strength and the other ceramic properties of the kaolin. The improvement was connected with the action of some secreted microbial metabolites such as soluble heteropolysccharides, monosugars and organic acids. The best results were achieved by continuous cultivation of bacteria in the presence of kaolin with a high relative humidity and subjected to periodic stirring.

Jan 1, 2014