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By W. Banda

"Trial application of air decks on a production shot improved fragmentation (32% reduction in x50). Empirical fragmentation models and digital image processing software were used to estimate fragment size distribution of the blasted muck pile. The x20, x50, and x80 passing fractions, and top size were 42, 265, 683, and 1,455 mm, respectively. Air-deck application reduced explosives load in blastholes, lowering total charging cost by US$20/hole (15% decrease) and the powder factor to an average of 0.86 kg/m3 (12% decrease). Blast results were 443,624 t of blasted material from the block (90% of total muck pile) was smaller than 900 mm.RÉSUMÉ L’application pilote de trous d’air dans le cadre du coup de mine effectué pour commencer la production a amélioré la fragmentation (une réduction de 32 % des x50). Des modèles empiriques de fragmentation et un logiciel de traitement numérique des images ont permis d’estimer la composition granulométrique des fragments du tas de déblais abattus. Les fractions de passé de crible de x20, x50, x80 et la dimension supérieure étaient représentées par des dimensions respectives de 42, 265, 683 et 1 455 mm. L’application de trous d’air a permis de diminuer la charge d’explosifs nécessaires dans les trous de mine, réduisant ainsi les coûts totaux de chargement de 20 $ US/trou (soit une réduction de 15 %) ainsi que le facteur de chargement (facteur poudre) à une moyenne de 0,86 kg/m3 (soit une réduction de 12 %). Les coups de mine ont résulté en 443 624 tonnes de matériaux abattus du bloc (soit 90 % du tas de remblais total) mesurant moins de 900 mm. INTRODUCTIONThe main objectives of production blasting are to achieve optimum rock fragmentation and to minimize overall production costs. Because blast fragmentation significantly affects the profitability of a mine, blasting is the first step of the size reduction in mining: An optimum size distribution is required to maximize the performance of mining and subsequent milling processes. If the fragmentation size distribution can be modelled and controlled, operations performance will improve. Blast fragmentation modelling is important in mineto- mill optimization: It allows the estimation of blast fragmentation distributions that can be modelled in downstream mining processes to determine the optimum blast design."

Jan 1, 2018

By W. J. D. Stone

In 1960, Magnetics International Ltd. undertook the development of the Jones High Intensity Wet Magnetic Separator in the Americas. Magnetics International had a number of possible applications in its own projects plus the intention of developing the equipment for sale to others. It was soon recognized that no matter how innovative a piece of mineral separation equipment may be, it takes many years and much finance before it is finally accepted for large scale use. For this reason, many good ideas die in their infancy. One of the chief reasons for such a time lag between conception and large scale implementation is the usual lack of finance to construct and put into operation a large demonstration unit. Even with a large unit for demonstration, the first major user usually requires a guarantee that is not normal in accepted separation equipment. Such problems are also normally accompanied by major design changes from the first conception.

Jan 1, 1971

By A. J. MacRae

Metallurgical furnaces are made up of complex multi-component systems that must function either together or in parallel for safe, and reliable operation. Thermal expansion of single material components experience induced stresses during heating and cooling, which can lead to cracking or failure. Multi component elements and systems can experience significant thermally induced stresses during both steady state and transient temperature conditions. Examples pertaining to temperature effects on refractory, copper cooling blocks, furnace shells, and complete systems will be discussed. The purpose of the paper is to highlight how stresses and strains are developed due to differential thermal expansion.

Jan 1, 2015

By P. J. Mackey, J. B. See, D. G. C. Robertson

The production of iron and steel and non-ferrous metals by pyrometallurgical processes will remain a critical element in meeting the demand for materials in both developed and developing nations. Given the important need to reduce and minimise greenhouse gas emissions the technological focus of future pyrometallurgical R&D by universities and industry alike must concentrate on sustainability issues such as improved energy efficiency, recycling and waste minimization. Continued efforts are also needed on process optimization and new process development with a view to reducing capital and operating costs of the new large “mega” plants. Using the academic and industrial backgrounds of the authors, the present paper reviews the current status of R&D in pyrometallurgy in university departments with a particular emphasis on sustainability issues. The role of industry and government laboratories is also reviewed although primarily for developed countries. The paper also includes comments and suggestions on the future requirements for education and R&D in pyrometallurgy in developed countries to maximise sustainability. It is also suggested that future R&D in pyrometallurgy will be even more concentrated in developing countries – most notably China.

Jan 1, 2014

By A. Ramage

Since late 2010, CH2M HILL has been working with a confidential client who holds a long-term commitment to sustainable development (SD). The commitment is aligned with all three elements of the triple bottom line: people and society, ecosystems and environment, and financial and economic systems. These commitments are carried forward by the firm?s executives, managers, and operational sites, and are evident in materials posted on the company?s public website. These materials include a formal sustainability report prepared in accordance with the Global Reporting Initiative (GRI) guidelines (GRI, 2006), a report that outlines key SD challenges and progress toward the GRI targets, and a delineation of risks and opportunities outlined in the firm?s Form 10-K and Annual Report. In keeping with its commitments to SD targets, our client wished to consider SD issues in its decision processes for facility expansion or new projects. The company engaged CH2M HILL to meet this goal, based on working relationships established through existing contracts and CH2M HILL?s leading capabilities in sustainable solutions.

Jan 1, 2012

By O. T. Berge

Development and production from open cut mines continued its vigorous growth trend during the year 1968. Material handling and transportation were again exposed to the use of larger equipment with shovels, trucks and front end loaders leading the way. Highlights of World Mining Activities Africa: The Anglo American Corp. opened a new high-grade copper mine in Zambia during the year. In Angola, the Companhia Minera do Lobita planned a 3 million ton iron ore production for 1968 from new mines which will ultimately produce 5 million tons per year. A feasibility study of Bethlehem Steel Co., for the development of large high- grade iron ore reserves in Gabon, was in final stages of completion this year and Pickands Mather and Co. continued its investigation of iron ore deposits along the Ivory Coast.

Jan 2, 1969

Several industrial-scale HydroFloat separators have recently been installed at Mosaic?s South Fort Meade beneficiation plant for the purpose of improving phosphate recovery and throughput capacity. This technology was implemented after numerous laboratory, bench-scale and on-site, pilot-scale test campaigns. The results from this detailed test work provided sufficient justification for the complete retrofit of the existing coarse and ultra-coarse flotation cells. Data indicate that the metallurgical results obtained with the full-scale separators are consistent with that obtained during both the bench- and pilot-scale evaluations. The benefits, theory of operation and commissioning of the equipment are also discussed.

Jan 1, 2007

By Keith A. Heasley, Timotlly M. Barton

Historically, the surface subsidence over underground coal mines has been predicted using empirical profile or influence functions which have little or no connection to the actual mechanics of the subsidence- Without a mechanistic basis, establishing the exact site-specific parameters to use in these empirical methods has been problematic. A practical subsidence predictive method based on mechanics has the appealing capability of allowing the determination of site-specific parameters from fundamental properties of the overburden with minimal field calibration work. This paper presents a case study where a mechanics-based, boundary-element program is used to calculate the surface subsidence associated with several panels of a Northern Appalachian longwall coal mine. The program used in this case study is called LAMODEL, and it incorporates a frictionless, laminated overburden into a general purpose displacement-discontinuity code primarily designed for calculating the stresses and displacements in coal mines or other thin seam or vein type deposits. In this paper. the program is used to calculate both the underground convergence and the resulting surface subsidence at three longwalls. The subsidence results from the model are compared with field measurements and analyzed The results from the case study in this paper demonstrate that the laminated model with calibrated properties can easily provide fairly accurate subsidence predictions and is fairly flexible for fitting measured subsidence. However, additional subsidence predictive case studies are recommended in order to ultimately evaluate the potential of the laminated overburden model for practical subsidence prediction

By William M. McKewan

The U.S. Bureau of Mines has established a wire rope research laboratory to examine the factors that affect the life of wire rope. Ropes of sizes ranging from 3/4 to 2 in. in diameter and from 2 to 35 ft in length were tested to determine their breaking strength, elongation, and torque. This was done to characterize the test equipment on ropes used in mine hoisting systems.

Jan 1, 1990

By AIME AIME

BESIDES commanding increasing importance as an alloying element in combination with ferrous and other nonferrous metals, the variety of uses for pure nickel continues to widen. For coinage it is growing in popularity. These coins have been minted for 27 countries in 72 issues representing 69 denominations. Approximately 3,000,000,000 pieces have been struck, the aggregate weight, of which amounts to nearly 14,000 tons. . Danzig, Iraq and Japan are the most recent governments to adopt, pure nickel coinage. France is adding the denomination of five francs to its other nickel currency; they replace silver pieces. Germany is now minting a new issue of one Reichsmark coins of pure nickel. The Japanese program for 1933 called for the issue of 35,000,000 10-sen pieces and 30,000,000 5-sen pieces. In radio tube manufacture the consumption of pure nickel was approximately twice that of 1932. During 1.933 the nickel plating process by which bright deposits may be plated

Jan 1, 1934

By G. P. Contractor

Medium and low carbon steels, modified with uranium, were studied in order to evaluate the influence of uranium on forge ability, mechanical 11roperties, response to heat treatment and microstructure. Uranium contents ranged up to 0.70 per cent. The medium carbon steels are hot short if the uranium content exceeds about 0.35 per cent. More uranium can be tolerated in low carbon steels. The hot shortness is caused by the formation of intergranular phase UFe2. Critical transformation temperatures, Jominy hardenability, and resistance to tempering are not significantly affected by the 11resence of uranium. Similarly, uranium has little or no effect on the tensile properties of carbon steels. The addition of uranium has a favourable effect 11n the stress-rupture characteristics and some beneficial effect on fatigue properties. However, more results are required for verification. In the steels investigated, it seems that most of the uranium carbide combines to form complex inclusions of U (0, C, N) or (C, N), rich in oxygen or nitrogen or both.

Jan 1, 1963

By Ludwig Hermann

"Phosphorus is required by every cell of living organisms and essential for plant growth. It is a non-renewable resource that must be mined from natural deposits, going gradually into depletion. Abundant secondary resources are available in sewage sludge and meat and bone meal, with the highest exploitable P concentrations in ashes that remain from their widely used combustion with energy recovery. ASH DEC has successfully removed heavy metals and transformed sewage sludge ash into a marketable P fertilizer by application of a thermo-chemical treatment process. Pilot scale investigations in which ash was treated proved that generally heavy metal limits required by fertilizer legislation can be attained. To achieve a high P availability for crops – an essential fertilizer quality feature – was a more challenging R&D task. Our presentation demonstrates the scientific approach and R&D results that lead from assessment of market requirements to licensed products.IntroductionPhosphorus (P) is required by every cell of living organisms. It is one of the major elements for plant nutrition and therefore essential for crop production. P supply in plant nutrition depends entirely on external inputs into soils [1]. This is achieved by P-fertilizers deriving from rock phosphate deposits that are gradually going into depletion. Serious prognoses anticipate that rock phosphate will be the first low running resource in the world [2]. In the EU, last year 2.530 kt of phosphorus (P2O5 in fertilizers) was consumed and only 313 kt (P2O5 in rock phosphate) was mined. Since 2007, rock phosphate prices have increased by 500% because of a tight supply situation [3].For these reasons, P recycling is becoming an increasingly important issue. Suitable secondary raw materials with regard to their high P-content and abundance are sewage sludge and meat and bone meal. In the EU 989 kt P2O5 are accumulated annually in theses materials, of which 632 kt P2O5 are permanently lost to landfills and other forms of disposal. The main reasons for their limited recycling are concerns on heavy metal contents and organic pollutants that may incite health hazards. As an additional shortcoming, the availability of P from these materials to plants is poor and storage and transportation are problematic issues [4, 5]."

Jan 1, 2008

Remarks of Mr. Robert W. Hunt, General, Superintendent, Albany and Rensselaer Iron and Steel Company., Troy N. Y.—In discussing Dr. Dudley's two most interesting papers, I feel a natural hesitancy in disagreeing with conclusions formed after such careful and conscientious work. But I think he has made his deductions from too meagre premises. The analyses of but twenty-five samples are entirely too few to justify the establishment of so important a formula. When we consider that he indirectly proposes to regulate an interest amounting, even at the present low prices, to over $20,000,000 per annum, we may well hesitate before accepting a formula based upon the chemical and physical analyses of but twenty-five steel rails. Dr. Dudley touches the keynote in referring to the proposed labors of the Government Test Commission. They based their hopes of attaining success upon the chemical and physical analyses of a very large number of samples, and in the only branch of investigation which the short-sighted policy of Congress has allowed them to complete, i.e., chain cables, we find that a dozen, twenty-five or one hundred tests gave no satisfactory results. It was only after many hundreds that they were enabled to' draw conclusions. There are so many circumstances hearing upon the life of a rail, that the task of extracting a correct result seems herculean. I presume I am right in stating that in our Northern latitudes early winter and spring months witness the breaking of the greatest number of rails, thus seeming to prove that an unstable road-bed has much to answer for. Then, again, broken and flattened wheels must be taken into account, but I am convinced that more rails have been broken by the treatment which they received before leaving the rolling-mill

Jan 1, 1879

Remarks Of Mr. Robert W. Hunt, General Superintendent, Albany And Rensselaer Iron And Steel Company., Troy N. Y. - In discussing Dr. Dudley's two most interesting papers, I feel a natural hesitancy in disagreeing with conclusions formed after such careful and conscientious work. But I think he has made his deductions from too meagre premises. The analyses of but twenty-five samples are entirely too few to justify the establishment of so important a formula. When we consider that he indirectly proposes to regulate an interest amounting, even at the present low prices, to over $20,000,000 per annum, we may well hesitate before accepting a formula based upon the chemical and physical analyses of but twenty-five steel rails. Dr. Dudley touches the keynote in referring to the proposed labors of the Government Test Commission. They based their hopes of attaining success upon the chemical and physical analyses of a very large number of samples, and in the only branch of investigation which the short-sighted policy of Congress has allowed them to complete, i.e., chain cables, we find that a dozen, twenty-five or one hundred tests gave no satisfactory results. It was only after many hundreds that they were enabled to draw conclusions. There are so many circumstances bearing upon the life of a rail, that the task of extracting a correct result seems herculean. I presume I am right in stating that in our Northern latitudes early winter and spring months witness the breaking of the greatest number of rails, thus seeming to prove that an unstable road-bed has much to answer for. Then, again, broken and flattened wheels must be taken into account, but I am convinced that more rails have been broken by the treatment which they received before leaving the rolling-mill * The remarks of the participants in this debate have been written out by the speakers, and are here given without any attempt to retain the order of the dis¬cussion. While the report does not, therefore, preserve the vigor and spontaneity of the debate, it is believed that it gains in value by giving the matured views of the speakers. The continuation of this discussion at the Pittsburgh Meeting, May, 1879 (beginning with remarks of Mr. Cloud on page 401), is appended for convenience of reference.-T. M. D., Sec'y

Jan 1, 1879

By C. A. Komar

The Bureau of Mines is investigating possible applications of acoustic energy at sonic and ultrasonic frequencies in petroleum production. A phase of this work involves measuring sound velocity through petroleum reservoir rocks. References and abstracts were prepared as a bibliography to make available to others some of the material obtained from a literature search covering the past applications and the present uses of sound. Laboratory and theoretical studies of the various parameters that influence the velocity of sound in porous media account for the wealth of information now available. Velocity of propagation of sound waves in porous sediments as a function of depth is a quantity frequently measured. Velocity logging systems, capable of measuring speed of sound waves in underground formations penetrated by wells, have been developed for interpretative studies. The close relation between acoustic velocity and porosity makes it possible to determine porosity from velocity logs. Most velocity log interpretation in terms of porosity is based on a formula developed by Wyllie and others known as the time-average relation.

Jan 1, 1963

By D. K. Crampton

ON giving thought to the subject of this paper, my first reaction was that many and striking changes have come about as a direct result of the war. However, more careful analysis indicates that few, if any, of these changes can be wholly attributed to it. The actual situation is that all these changes were conceived and most of them at least partially executed in re- cent prewar years, it remaining the role of war to achieve results in a fraction of the time that might normally have been taken, lacking its driving impulse. The further discussion will therefore be with the premise that the individual changes have been greatly hastened rather than directly and primarily caused by any war conditions. Co-operation among copper alloy producers on production problems is agreed to be much worth while. The industry was too long noted for jealousy and secrecy as to equipment, methods, and even materials produced. Gradually, a more open and co-operative policy evolved but even just prior to the war the interchange of ideas was relatively cautious and limited. The need for a great increase in production in record time fostered a more co- operative attitude; exchange of ideas and experience concerning all phases of production increased tremendously to the benefit of the individual participants and thus the war effort, too. This more united effort has undoubtedly led to many specific improvements in process or equipment and these in turn to more rapid and economical operation than could have taken place on an each-for-himself basis.

Jan 1, 1944

By W. H. Oppelt

A lignite from west-central North Dakota (Mercer County) was dried by the Bureau of Mines by the Fleissner process at saturated steam pressures to 1,500 pounds per square inch absolute (p.s.i.a.). Normally, the process is operated at pressures of 200 to 370 p.s.i.a. At the highest pressure the temperature of the saturated stearn is 596° F. The purpose of the investigation was to evaluate the influence of very high stearn pressure and temperature on moisture removal, steam consumption, and physical and chemical characteristics of the dried lignite. Two drying cycles were used: A normal cycle, corresponding to previously established standard time requirements, and an accelerated cycle, wherein time requirements were determined by boiler capacity and handling speed. Blank tests to determine stearn requirements for heating the empty autoclave were performed for each cycle and each test condition. Moisture removal, final moisture content, net steam consumption, and size stability of the dried lignite were determined.

Jan 1, 1959

By M. A. Elliott, H. H. Schrenk, L. G. Berger, John C. Holtz

"INTRODUCTION Interest in the possibility of using Diesel 6/ engines for haulage power in mining and tunneling is increasing in the United States, owing largely to the reported successful use of Diesel locomotives in European coal mines and to the comparatively recent development of automotive Diesel engines in this country. The extent of this interest has been evidenced to the Bureau of Mines by numerous requests for information as to the factors that must be considered if Diesel engines are to be used safely underground.Proponents of the application of the Diesel engine to underground haulage base their claims for its safety upon a comparison with the gasoline engine, assuming that (1) the carbon monoxide content of Diesel exhaust gas is always low and that (2) fire and explosion hazards from Diesel fuel are minimized because of its low volatility. In these respects the Diesel engine appears less hazardous than the gasoline engine, whose use underground has been discouraged by the Bureau of Mines and other organizations interested in safety in mining. However, such generalizations cannot be accepted as conclusive evidence that safety is inherent in Diesel engines in underground service, as European experience indicates that certain hazards may accompany their use. Such hazards were discussed in a previous publication 7/ that reviews developments in the use of Diesel locomotives in European coal mines.The Bureau of Mines has initiated a study of the hazards that may attend the use of Diesel engines underground to obtain first-hand information that may serve as a basis for recommending sale practices under conditions existing in the United States."

May 1, 1940

By R. H. Fett

T HE APPROACH to maintenance must always be ?completely positive: there must be no question of putting off difficult problems until it is more convenient to tackle them. By this it is meant that a piece of machinery or equipment which, by experience, is known to be due for a check should not, merely because it appears to be operating satisfactorily, be left until it reaches a critical .condition and breaks down. The mentality of the Maintenance Manager must be completely orderly and methodical and he should, in fact, possess a ledger-book mind, having a debit and credit outlook. The debit side would be that applying to time out of service, cost in wages, material, personnel involved, etc., and the credit side that relating to continuous operational time of the locomotive and therefore to the ultimate benefit of the mine and the personnel who work there. The Maintenance Manager is not concerned with design problems, and although he and the personnel under his jurisdiction are not engaged in productive work, he and his staff do, nevertheless, add greatly to or detract from the overall efficiency of the organization. Provided the machinery placed in his care is good to start with, he must take the best steps he possibly can to keep it running. However, he may, on occasion, be forced to improvise and this is where the ingenuity of a clever man rises to the occasion.

Jan 1, 1956

By AIME AIME

MANY interesting papers, opportunity of seeing o1d friends, and an exposition showing all that is latest in equipment, all were factors in bringing a large crowd to Detroit during "Metal Week," October 2-6. The Institute's Iron and Steel and Institute of Metals Divisions held technical sessions at the Statler Hotel on October 4 and 5, and that hotel was also headquarters for the American Society for Steel Treating and the American Society of Mechanical Engineers, both of which also had technical sessions. The American Welding Society and the Wire Association met at the Book-Cadillac Hotel, and the exposition was staged at Convention Hall, out Woodward Avenue. All in all it was a big week for men interested in metal working. One of them stated to your reporter on the train en route to Detroit that this was the one convention that he never missed, and doubtless others felt the same way about it.

Jan 1, 1933