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By A. B. Parsons

LAST YEAR (1934) saw the completion of a ten-year program of reconstruction and modernization of the world's largest lead- smelting plant, that of the ' Broken Hill Associated Smelters Proprietary, at Port Pirie, South Australia, which has a capacity for smelting and refining 220,000 (short) tons of lead per year. It deals with the entire output of lead concentrates from the famous Broken Hill district in Australia, being owned .jointly by the three leading companies: North Broken Hill, Broken Hill South, and the Zinc Corporation. These companies, together with the Sulphide Corporation, are credited with a production of 198,000 tons of lead in 1934. When one says regarding any metallurgical plant that modernization is "completed" he should add "for the moment." Development in the art of metallurgy and in the equipment used never ceases; that which seems close to the last word today is likely to be obsolete in a few years even in a process so well standardized as smelting and refining lead. However, the reconstruction at Port Pirie has altered the procedure materially. More im-

Jan 1, 1935

By L. Uotinen, M. Rinne, R. Mishra

Underground mining gives rise to geotechnical hazards. A formal geotechnical risk assessment can help to forecast and mitigate these hazards. Frequentist probability methods can be used when the hazard does not have many variables and a lot of data is available. However, often there is not enough data for probability distributions, such as in the case of new projects. The risk assessment is often subjective and qualitative, based on expert judgement. The purpose of this research is to present the use of Bayesian networks (BNs) as an alternative to existing risk assessment methods in underground mines by combining expert knowledge with data as it becomes available. Roof fall frequency forecasting using parameter learning is demonstrated with 1141 sets of roof fall data across 12 coal mines in the USA. The prediction is nearly identical for individual mines, but when multiple mines are evaluated it is difficult to find a single best fit distribution for annual roof fall frequency. The BN approach with TNormal distribution was twice as likely to fit the observed data compared to the Poisson distribution assumed in the past. A hybrid approach using BN combining multiple probability distribution curves from historical data to predict annual roof fall is proposed. The BN models can account for variability for multiple parameters without increasing the complexity of the calculation. BNs can work with varying amounts of data, which makes them a good tool for real-time risk assessment in mines.

Jun 1, 2021

By P. R. Jochens

South Africa depends to a considerable measure on the exploitation of mineral reserves and the processing of these minerals. One of the prime requirements for the mining and metallurgical industry to continue in this vital role is access to sufficient energy in a suitable form. Hence, four important questions are discussed: Does South Africa have sufficient energy for the processing of its minerals and metals! Will the cost of energy allow South Africa's minerals and metals to compete on world markets? Can mining and metallurgical processes become more energy-efficiency Can mining and metallurgical processes be adapted to the various forms of energy that may have to be utilized in the future? It is concluded that about 26 per cent of the extractable reserves of coal would be required in the mining and processing of 50 per cent of South Africa's reserves of gold, platinum-group metals, copper, iron, ferrochromium, and ferromanganese. However, the reducing agents required exceed the extractable reserves but not the total estimates of mineable in situ resources of metallurgical coal and anthracitic coal. Even under the severe constraint that coal could become virtually the sole source of energy, only about three-quarters of the extractable reserves of coal would have been consumed by the year 2025. The reasonably assured resources of uranium metal that can be recovered at less than $80 per kilogram are considerable and, at current conversion efficiencies to electricity, are equivalent to one-fifth of the extractable reserves of coal. The rate of exportation of energy in the form of U30. was about five times that of coal in 1978. It is pointed out that the price of energy has a direct effect on the competitiveness of metals, and, although constituting only a small proportion of the selling price of precious metals, it represents a significant proportion of the selling price of copper and metals recovered from oxide ores. The scope for the conservation of energy appears to be greater in the extraction and conversion of primary energy-carriers to electrical energy than in other mining or metallurgical fields. Provided that alternative sources of energy can be converted to electrical energy, they can be applied to the mining and metallurgical industries. The decision as to which type of energy should be used in specific mining and metallurgical situations is complicated, and is likely to be subjected to closer scrutiny than in the past. The hope is expressed that the tentative conclusions reached will give rise to more-quantitative analyses from those qualified to undertake such an exercise. Inevitably, the questions asked at the outset give rise to more questions, and the more interesting ones are posed in the context of each conclusion.

Jan 1, 1980

By A. E. Moss, J. K. Gustafson

MEASURED in terms of ore tonnage, the New Quebec and Labrador iron ore fields promise to rank with the greatest iron ore districts of the world. Over 400 million tons of high-grade ore for direct shipping have been discovered to date. Much greater amounts of lower-grade beneficiating ores are indicated by outcrops. Many hundreds of square miles of iron formation await testing. By 1954 iron ore will begin to move towards American blast furnaces, and shortly thereafter the annual rate of production is expected to reach 10 . million tons. To bring this vast project into being over $200,000,000 will have been spent for exploration and development, mining equipment, hydro plants, townsites, the building and the equipping of . a 360-mile railroad, and the construction of docks and ore-handling facilities. The most important iron ore deposits are located over 300 miles from tide water, see frontispiece and also Fig. 1. The frontispiece shows principal sources of iron ores and manganiferous iron ores for the U. S. and Canadian steel industry, and the major smelting districts are shaded on the map. No navi- gable rivers lead into the interior. When work was . commenced on this project there were no roads, no railroads, no communication ,system, no inhabitants, and no adequate maps either topographical or geological. The geological field season was limited to approximately 100 days per season. The obstacles facing this enterprise were many and varied. Its success will be due to the integrated team work of people of diverse skills. Explorers, Indian guides, prospectors, geologists, surveyors, mechanical, civil, electrical, and mining engineers,

Jan 1, 1954

By John Nagy

Dust explosion data obtained in laboratory tests by the Bureau of Mines are presented for 181 miscellaneous materials that present an explosion hazard. Data are given also for 50 dusts that present primarily a fire hazard and for 88 dusts that did not present an explosion hazard.

Jan 1, 1968

By R. H. Jefferson

An electrochemical method to selectively determine sulfur dioxide in the presence of sulfur trioxide was investigated. A hydrophobic gas-permeable membrane separates the gas sample solution from an internal filling solution containing a fixed quantity of chloride ion and a sufficiently large excess of sodium bisulfite so that its concentration may be considered constant. Sulfur dioxide diffuses through the membrane to dissolve in the internal filling solution and liberates an equivalent quantity of hydrogen ions. The electromotive force between a precision-ground, flat-ended pH electrode, which acts as the sensing element, and a chloride sensing electrode, which acts as the reference element, gives a direct measure of S02 in the gas sample solution. Calibration curves in water, tetrachloromercurate (TCM) , and citrate buffer absorption solutions were closely parallel with slopes in their linear segments, ranging from 57 to 52 mv/decade of S02 concentration. The slopes compare reasonably well with the theoretically expected slope of 58 millivolts at 21° C. The water standard curve was linear with respect to the logarithm of S02 concentration from 1 to 1,000 ppm S02; the TCM standard curve was linear from 10 to 2,000 ppm S02; and the citrate standard curve was linear from 30 to 5,000 ppm S02' The high efficiency and nontoxicity of citrate favor it as a substitute for the conventionally used TCM in the absorption solution.

Jan 1, 1976

By Bieniawski, Z. T.

The importance of understanding the phenomena associated with rock fracture has long been fully appreciated in rock mechanics. This is clearly apparent from the special attention paid to rock fracture in the comprehensive papers published within the past four years. These papers present a picture of how the knowledge of brittle fracture of rock was gradually enriched and also show that what was often taken for granted three or four years ago is no longer considered as valid today.

Jan 1, 1972

By M. Yekich, W. R. Reed, G. Ross, M. Shahan

"Canopy air curtains (CAC) on roof bolting machines have been proven, through laboratory and field investigations, to protect miners from respirable dust, preventing dust overexposures. Another desired application is to develop a CAC that is mounted in the compartment of a shuttle car to protect the operator from dust. The challenges faced with this design include mine ventilation rates in tandem with the shuttle car tram speeds, causing cab airspeeds that may exceed 600 fpm, as found in this study of a central Appalachian underground coal mine. Prior research and laboratory testing indicate that successfully protecting a miner in high air velocities is difficult to achieve because the clean air from the CAC is unable to penetrate through the high velocity mine air and make it to the breathing zone of the operator. During this investigation by researchers from the National Institute for Occupational Safety and Health (NIOSH), dust concentrations of the shuttle car operator were measured. Also, air velocities experienced by the operator were measured using a recording vane anemometer. Results from the survey indicate that the highest exposure to respirable dust (2.22 mg/m3) occurred when the shuttle car was loading at the continuous miner, where there was an average airspeed of 157 fpm. While tramming, the operator was exposed to 0.77 mg/m3 of respirable dust with an average airspeed of 203 fpm. This study indicates that a CAC system can be designed to greatly reduce an operator’s exposure to respirable dust by providing clean air to the operator, since the majority of the operator’s dust exposure occurs in air velocities less than 200 fpm. INTRODUCTION NIOSH has issued a contract (#200-2015-63485) with Marshall University and J.H. Fletcher & Co. (Salem et al., 2016) to develop a canopy air curtain (CAC) for coal mine shuttle cars. The proposed design maintains a similar design to the roof bolter CAC by providing filtered air via a blower over the operator. The plenum, which will provide the uniform airflow over the operator, is anticipated to be built into the shuttle car canopy. One of the main interferences with a CAC is ventilation airflow perpendicular to the plenum airflow [Engel et al. 1987]. This ventilation airflow, if the velocity is significantly high, can shear the downward flow from the plenum. The shear caused by the ventilating airflow can reduce the effectiveness of the CAC by either disrupting the downward flow or allowing contaminated mine air into the CAC zone of protection."

Jan 1, 2018

By F. Habashi

"Extractive metallurgy was divided into the three sectors pyro-, hydro-, and electrometallurgy in 1959 when Professor Joseph Newton at the Idaho School of Mines in Moscow mentioned this in his book Extractive Metallurgy. Pioneer hydrometallurgists who built this discipline can be traced to the alchemists in the ninth century. It is now a mature subject of great importance in which pressure plays a vital role. Short biographies of some hydrometallurgists and the processes they invented are briefly outlined.INTRODUCTIONHydrometallurgy is the use of aqueous solutions to recover metals from ores. It is a relatively new discipline when compared with pyrometallurgy the use of fire to melt ores and recover metals which was practiced in ancient times. Hydrometallurgy can be traced to the time of alchemists whose concern was the transmutation of base metals into gold. Although alchemists did not succeed in their venture yet they described many reagents that are useful today. For example, they prepared sulfuric acid by distillation of iron vitriol, muriatic acid by distillation of sulfuric acid with salt, and nitric acid by reaction of sulfuric acid by reaction of sulfuric acid with salpeter. Jabir Ibn Hayyan the Muslim alchemist who lived in the ninth century (Figure 1) described aqua regia a mixture of nitric and hydrochloric acid that can dissolve gold although either acid has no action on gold. THE MIDDLE AGESIn the Middle Ages, it was reported that copper was recovered at Rio Tinto in Spain by allowing copper-containing pyrite to be exposed in piles to the action of air and rain. Copper sulfate solution obtained was treated with pieces of iron to precipitate metallic copper—a process that was called cementation. Georgius Agricola (1494–1555) (Figure 2) a medical doctor in Saxony who used to visit mines and smelters to examine miners and metal workers, described in his book De Re Metallica the parting of gold, i.e., separating of silver from gold by acids."

Jan 1, 2016

By J. D. Pitts

The worldwide production of iron ores was approximately 880 million metric tons in 1975. This level is the result of an annual growth rate of nearly four percent during the period 1967 to the present. The high growth rate was particularly significant in that two relatively severe worldwide recessions occurred in 1971 and 1975. The current upturn in world economic growth will probably allow future annual iron ore production growth rates in excess of the four percent figure, and, in fact, the International Iron and Steel Institute (IISI) has predicted that a five percent rate should be realized through 1985. The IISI figures would indicate a 1.4 billion metric tons per year output by 1985 or an increase in current production levels of around 500 million metric tons per year (MMTA)1. Even the more conservative four percent growth rate prediction from historical data would provide an 2 increase over current figures of nearly 350 MA by 1985. A large portion of world iron ore production is being provided by large resource-rich countries with relatively new industrial bases. These countries are typified by heavy export of raw materials such as iron ore and ore products and a large capital investment in the facilities to recover these raw materials. Brazil and Australia are typical of such countries and, indeed, their production of iron ore in the period 1967 to 1973 increased at annual rates of 17 to 30 percent, respectively, The continual reassessment of resources in these and other major iron ore exporting countries such as Venezuela and Liberia would indicate chat these high growth rates may continue for some years to come to meet anticipated world demand for raw steel production.

Jan 1, 1976

By J. E. Berg

This paper3 describing the mining methods at the Page mine operated by the Federal Mining & Smelting Co., is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The Page mine is the most westerly of the producing lead-silver-zinc mines in the Coeur d'Alene mining district of Idaho, being situated 5 miles west of the city of Kellogg and at an elevation of 2,677 feet above sea level. It may be classed as one of the new active producers, of the district and owes its present activity largely to the development of floatation.

Jan 1, 1930

By N. A. C. Smith, D. D. Stark

"Sulphur is apparently a normal Constituent of crude petroleum, but in most crudes is present in percentages of less than one-half of one per cent. Some crudes, however, contain more, and occurrences have been reported of heavy asphaltic oils with as much as five per cent of sulphur.Occurrences of Sulpher-bearing CrudesIn North America, the fields rest of the Mississippi River are almost entirely free from sulphur oils, the time oil from Northern Ohio and Indiana, and the Potrolia crude in Ontario, being practically the only ones which contain sulohur in amounts over 0.5. per cent. In the Mid-Continent district the production of high sulphur crude in general is small and unim¬portant. The two main excentions are the Healdton field in Oklahoma and the El Dorado field in Arkansas, both of which produce oils with considerable sulphur content. In the Wyoming field, one sand, the Ember Sandstone, pro¬duces a crude of high sulphur content, and it is probable that this crude rill be of considerable importance as production increases. At present, however, very little crude is produced from this formation. In the Gulf Coast conditions are irregular, some crudes being low in sulphur and others comparatively high. The same is largely true of California. The crudes of Mexico contain notable amounts of sulphur, and as they have been of great commercial importance in this country, a typical sample of light Mexican crude was selected for the present study. It is probable that the results obtained poly also (but to a lesser degree) to other sulphur-bearing oils. An analysis of this crude will be found in Table 3, also analyses of other typical sulphur-bearing crudes from different sections of the United States."

Mar 1, 1924

By R B. Venugopal, P Staples

The selection of the mode of transport for moving bulk materials is never a simple task as there are various concerns/considerations applied to the selection of the most practical and cost-effective mode of transport to be used to move bulk materials. This paper examines various alternatives for moving ore from a mine at the top of a mountain to a process plant below (some 5000 m apart and a vertical drop of 650 m). The terrain of the mountain section of the route has added its own specific requirements, resulting in the final selection of a pipe conveyor for this application. The paper further addresses the final selection of hardware used in the implementation of the solution.

Jan 1, 2005

Secretary's Note.—M. Beutter's introductory remarks, being simply a resume of Prof. Hone's paper, with a disclaimer of the intention to criticise it, have been omitted, and the remainder of this contribution lias been somewhat condensed, without omitting any essential statements. M. Beutter, St. Etienne, France* (communication to the Secretary†):—Professor Home observes in $ 47 of his paper that the fluid-compression of steel diminishes piping by forcing the liquid and viscous metal, while the pipe is forming, or after it has formed, into the space so produced, and proceeds to study the different systems of compression, alluding to the four principal ones: Whitworth, Illingmorth, Williams, and Harmet. Having now for many years had in use the last-named process, that of M. Henri Harmet, I shall attempt to explain the difference between it and the three other processes named. The Harmet process does not diminish or close the pipe after it has formed, but prevents it from forming; and I may add that it is the only one of the four which produces this result. It is true that the Whitworth process diminishes the interior hollow by localizing it around the central axis of the ingot, which is afterwards removed by trepanning the hollow forg-ings for which this process has been, I believe, always exclusively used. The Illingworth and Williams processes, which, in my opinion, are applicable only to small ingots, of necessity allow the pipe to form, or (to use the expression of Professor Howe) they allow the surface of the lake of liquid steel to sink into the interior of the ingot, since they involve waiting a certain time before compression, so that (in the case of the Williams process) the ingot-mold can be opened without danger, or (in the case of the Illingworth process) so as to avoid the risk that the steel may enter the grooves produced by the removal of the distance-bars. During the time required for

Jan 1, 1908

By Tatiane Haskel

A utilização de ligas Al-Si tem se expandido industrialmente principalmente no setor automobilístico. Cabeçotes, blocos de motor, rodas entre outros são exemplos de componentes produzidos com essas ligas. Estes componentes normalmente estão sujeitos a carregamento cíclico. O objetivo desse trabalho foi estudar o comportamento da liga A356 utilizando corpos de provas submetidos à fadiga por flexão rotativa nas condições brutas de fundição e tratadas termicamente por T6. Corpos de prova para ensaios de tração e de fadiga foram obtidos por fundição por gravidade em coquilhas. A comparação dos resultados foi realizada com os resultados do limite de resistência, do limite de escoamento, do alongamento e das curvas S-N. Adicionalmente análises fractográficas foram realizadas para verificar o comportamento de fratura. A liga tratada termicamente apresentou melhores resultados no ensaio de tração e de fadiga na faixa de 103<N<107.

Aug 16, 2017

By W. K. Smith, V. P. Krueger, D. C. Mulder

"AbstractThis paper describes the geological procedures used to evaluate two mineable high-volatile C bituminous coal seams at Coal Valley , located in the outer foothills belt of the Rocky Mountain Eastern Slopes in west-central Alberta. Lexco Testing Ltd., the exploration arm of Luscos: Ltd., owns and operates an all -weather geophysical logging system which provides gamma, focused density , single-point resistance and caliper logs in a single pass. A mathematical analysis for a theoretical interpretation of the single-point resistance log confirms empirical research that bed boundaries are located at a point 10% from the bottom of the curve. A unique and efficient triple-tube, wireline rotary coring system cuts an undisturbed 0.076m- diameter core in a plastic liner at recoveries exceeding 90% . Although only 10% of the total footage is cored, it provides vital analytical and geotechnical data, and, when integrated with the geophysical logs, improves the quality and extends the usefulness of interpreting both sets of data. All data are programmed to produce computerized structure contour, isopach, isoratio and isoquality maps, and volume calculations.General IntroductionTHE COAL VALLEY AREA is located in the outer foothills belt of the Rocky Mountain Eastern Slopes, 60 miles (96 km) by road southwest of Edson, Alberta. Luscar Ltd. holds leases which total 49,000 acres (19,830 ha) , of which 18,300 acres (7,410 ha) have been assigned to the Coal Valley mine area (Fig. 1 ) . There are two Paleocene high-volatile C bituminous coal seams initially developed for mining within a total stratigraphic interval of 750 feet (230 m ) (Fig. 2 ). These seams strike generally NW, and in the undisturbed areas generally dip westerly from 10 to 30 degrees."

Jan 1, 1977

By Jorge Madias

A Aceros Arequipa é a maior siderúrgica do Peru. A empresa opera uma planta em Pisco, com uma aciaria para 850.000 t anuais de aço líquido, e uma capacidade de laminação de 1.250.000 t anuais de produtos longos. Um projeto de integração vertical incluindo coqueria non-recovery, sinterização e alto-forno foi considerado. Como parte do projeto, um forno piloto de coqueificação foi instalado, com o intuito de testar carvões próprios e importados e obter a máxima participação de carvão local nas misturas. Foram testados sez carvões peruanos e antracito. Os carvões importados escolhidos foram três da Colômbia e quatro dos Estados Unidos. Levando em conta as baixas propriedades dos carvões próprios, foi introduzida a estampagem da carga. A máxima participação dos carvões locais, mantendo a qualidade requerida, foi obtida com 80% de carvão peruano, e 20% de um carvão columbiano. Pode-se usar até 10% de antracito, junto a 60% de carvão peruano e 30% de carvão colombiano.

Oct 30, 2017

By Sunil S. Gandhi

Magmatic-hydrothermal deposits rich in magnetite and/or hematite form a broad group that includes monometallic Fe deposits and polymetallic (mainly Cu and Au) deposits. They show a considerable variation in deposit characteristics, but share the genetic processes of magmatic differentiation and related hydrothermal activity in intermediate to felsic melts, and in some cases involve brines and/or meteoric waters during mineralization. They include several world-class deposits. They range in age from Proterozoic to Recent, and form important metallogenic districts in Scandinavian, Canadian, Brazilian and Australian Shields, Circum-Pacific regions, and in China, Iran and Turkey. Monometallic deposits have been important sources of iron in the past and still contain significant resources of the metal, e.g., the Kiirunavaara deposit in Sweden. The giant Olympic Dam Cu-Au-Ag-U-REE deposit was discovered in 1975, and since then explorationists have focussed on search for analogues worldwide. This has brought to light a number of economically important new deposits and prospects, including examples in Canada. The discoveries have in turn prompted considerable research on individual deposits and the group as a whole. This short paper is an attempt to summarize the main aspects of the group from the literature cited in Gandhi and Bell (1996), and from the papers published recently in two milestone volumes on these deposits, edited by Porter (2000 and 2002).

May 1, 2003

By C. R. Tinsley

A strictly limited number of specialist project finance banks exists, with the necessary specialist personnel able to address project cost-competitiveness, cost and commodity forecasting, joint venture negotiations, and completion and sales undertakings. Different techniques of internal bank appraisal are applied, with the usual equity investment project valuation criteria being seldom useful for loan assessment purposes. Company attention paid to the preparation of a sensitivity structured bankable presentation can prove most effective for securing development project finance. Substantial scope is possible for savings of time and money.

Jan 1, 1985

By Clark Woodland, William E. Stanley

Mining companies have been required to enter a "new era of management" in the 1980's as they strive to become more efficient in an increasingly competitive market place. One response for many companies has been to modify their mine accounting systems to make them more effective for cost control and decision-making. This paper discusses some of the major issues in developing and implementing a standard costing system as part of improved management reporting and cost control procedures. It describes the key features and benefits of a computerized standard costing system with particular emphasis on budget-setting and variance analysis. It also identifies important factors to be considered in order to achieve successful project planning and Implementation.

Jan 1, 1987