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By Hal M. Lewers

IN the past few years and especially since the beginning of World War No. 2, gold has attained a new, important. and critical place in the international scene, and in world affairs. In the past, as far back as history records, most wars have been waged for the purpose of acquiring it from someone else by conquest. But now, the most titanic struggle of all time is being waged with the avowed purpose of not only destroying it, but of destroying all that it stands for and represents. A tradition dating back to ancient Rome, affirms that battles are fought by men with weapons, but wars arc eventually won by gold. The validity of that tradition is now being subjected to its major test. Hitler has proclaimed that in his new world order, the work dollar or reichsmark, a beautifully engraved paper currency representing only a theory of value, based on unit of work and production, will become the supreme medium of world exchange, and that gold eventually will he valueless and obsolete.

Jan 1, 1942

The London Metal Exchange began its first official session of aluminum trading on Monday, October 2, LME prices based on 3-month forward contracts opened Monday at 52.4 cents per pound, fell midway through the week to 52.3 cents and ended Friday at a high of 52.7 cents. For the week, LME metal averaged 52.5 cents. Although Reynolds Metals Co. and Aluminum Co. of American continued in September to value unalloyed 99.5 percent aluminum ingot at 53 cents per pound, other producers were at higher positions of 55-57 cents. Alcan Aluminum Corp. of Alcan Aluminum, Ltd., a Canadian producer, increased prices for its U.S.-marketed ingot by 2 cents to 55 cents per pound, effective September 21. New York merchants increased ingot quotes by approximately 0.5 cents to 52.8-53.5 cents per pound.

Jan 1, 1978

By Joan Weinberg

The economy continued to expand during the third quarter, as real GNP rose at a seasonally adjusted annual rate of 3.8%, up from 2.5% in the second quarter (table 1). Continued job gains (see below), higher incomes, and an increase in installment debt, resulted in a nearly 20% increase in consumer spending on durable goods. Consumer expenditure on nondurables fell slightly, while spending on services continued at a moderate pace. Nonresidential fixed investment climbed nearly 24%, as producers purchased more durable equipment. Residential fixed investment was adversely affected by rising interest rates, which slowed new home construction from January to August, 1987 to a rate 11.2% below a comparable period in 1986. Net exports of goods and services deteriorated slightly, after three consecutive quarters of improvement. The volume of net exports has risen 15% for the year, contributing to economic and employment growth, but large price increases on imports have slowed the improvement in the nominal trade balance. Although U.S. goods have declined in price relative to foreign goods because of the devaluation of the dollar, faster growth in exports is hampered by austerity programs in developing countries, and emphasis in Germany and Japan on curtailing inflation and fiscal deficits.

Jan 1, 1987

1. Domestic Production and Use: In 1978, 12 companies operated 31 primary aluminum reduction plants, with 3 firms accounting for 65% of production capacity. Washington, Oregon, and Montana accounted for 31% of the total capacity; Gulf Coast States 23%; Northern States 26%; and other Southern States 20%. Based on published producer prices, output of primary metal in 1978 was valued at $5 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1978, building accounted for about 25%; packaging 22%; transportation 23%; electrical 11%; consumer durables 8%; and other uses 11%.

Jan 1, 1979

By A. T. van Zyl, M. Mthenjane, M. J. Cole

Growing global concern over the impacts of climate change, attributable largely to fossil fuel energy sources, has led to the widely shared goal for a ‘just transition’ to cleaner energy and reduced dependence on carbon-based fuels. As the world’s 14th biggest CO2 emitter and being particularly vulnerable to the impacts of climate change, South Africa must embark on a just transition pathway. This paper reviews expected coal mine closures and associated community vulnerabilities and local governance challenges in South Africa. Decommissioning schedules for all coal-fired power stations and operating coal mines are plotted, and 69 mining host communities and 21 municipalities are mapped, classified, and described. Community socio-economic profiles are measured using a set of SDG indicators and census data and municipalities assessed through financial audits. Our research shows that five coal-fired power plants (8.9 GW) and 15 coal mines (29.5 Mt/a) will probably close by 2030, and a further four plants (14 GW) and 23 mines (106 Mt/a) by 2040. Thus, the shift to cleaner energy will likely occur without the premature closures implied by the just transition. The impact of mine closure on the 2.5 million residents of host communities will be significant, particularly as levels of income, employment, and education are already very low and many municipalities are in financial distress. The South African approach to the just transition needs to take local realities into account and the narrative must support an effective transition that does not undermine energy security and economic growth.

Jun 5, 2023

By W. Chi, R. Regan, R. A. Washington

"In uranium mines, the purification of underground mine air can be accomplished by the removal of dust particles and radon daughters using filters. Full-scale statistically designed experiments with flow rates up to 10,000 cfm have been conducted at Denison Mines Ltd. on mine air filtration with vermiculite as a filter material. Various filtration bed thicknesses were chosen, with different face velocities through each bed thickness. Results on total dust, respirable dust and radon daughter collection efficiencies were analysed statistically. It is shown that these collection efficiencies are directly related to the filter bed thickness. However, the different face velocities seem to affect only the collection of radon daughters. Optimum collection efficiencies for a clean bed of about 30% were found for respirable dust and radon daughters, and about 41>% for total dust, using an 8-in.-thick bed and a face velocity of 500 fpm. Dust build-up on the filter bed during operation led to an increase in collection efficiency, reaching 40 to 60% after two weeks."

Jan 1, 1973

By Mohsen Mohammadi, Edward Cyr

"To date, several studies have been performed on the static mechanical properties of SLM-AlSi10Mg alloy. There have also been more recent studies on the relation between scan strategy, texture, and mechanical properties of SLM metals and composites. However, there is a huge knowledge gap in the available literature regarding texture and mechanical behavior of SLM-AlSi10Mg alloy under high strain rates. Therefore, in this study, dynamic mechanical behavior of AlSi10Mg_200C alloy manufactured by DMLS technique was investigated at high strain rates ranging from 900/s to 1700/s using Split Hopkinson Pressure Bar. Texture using X-ray diffraction technique of the initial samples were measured. The yield strength, peak flow stress, and ductility increased in all samples with increase of strain rate. TEM studies have also revealed evidence of continuous dynamic recrystallization in grains after 900/s–1700/s strain-rate tests. A Taylor polycrystal crystal plasticity constitutive model was then developed to capture and predict the texture evolution and mechanical response under dynamic loading, using plastic work as a critical parameter for the onset of recrystallization.INTRODUCTION Additive manufacturing (AM) powder techniques are among the fastest advancing breakthroughs in manufacturing in recent years, defined by a bottom-up layer by layer process of joining with energy input from lasers or electron beam (Herzog et al., 2016; Gibson et al., 2015). Among alloys fabricated by SLM, AlSi10Mg is of high interest to industry and academia due to its low density, high specific strength and excellent corrosion resistance, making this alloy a viable contender for aerospace, automotive, and marine applications. Circumstances such as car crash or bird aircraft strike hazards subject potential additively manufactured AlSi10Mg parts to impact loadings. This drives an interest in understanding and predicting dynamic behaviour of these alloys. AlSi10Mg is the AM counterpart of A360 die-cast aluminum, which possess hypoeutectic microstructure (Li et al., 2015). Up to the present time, many studies have presented the mechanical properties of SLM-AlSi10Mg alloy. The mechanical properties and microstructure of AlSi10Mg produced by selective laser melting (SLM) or DMLS techniques can be controlled using different parameters, such as feedstock powder (Asgari et al., 2017), and process parameters (Olakanmi et al., 2015). The microstructure and mechanical properties of AlSi10Mg can also be controlled using post heat treatment after SLM process Li et al., 2016). The mechanical properties of SLM-AlSi10Mg are sensitive to strain rate and can both change under quasi-static (Rosenthal et al., 2017) and high strain rates (Asgari et al., 2018). However, a significant knowledge gap in available literature regarding modeling these behaviours, and especially micromechanical modeling of dynamic behaviour."

Jan 1, 2018

By AIME AIME

THE following paragraphs comprise such information as the Secretary has been able to obtain concerning the members and associates whose deaths have been reported. Further particulars or corrections of errors, and biographical data concerning deceased members or associates not already noticed in this way, are solicited. [SECRETARY'S NOTE.-All of these notices have been revised, and some of then have been more or less completely prepared, by me. To those which contain more particularly the expression of my personal feeling, my initials have been appended. The labor of preparing or editing these paragraphs has been in many respects both welcome and interesting, on the one hand, and sorrowful, on the other. In going through the list, I have repeatedly felt like one who, visiting the Morgue, suddenly comes upon the pale face of a dear friend, of whose death lie was not aware ; and, even when this fact was known to me, the work of recording it has brought upon me a flood of recollections, almost preventing the discharge of that official duty. The list for 1907 seems to me to he peculiarly sad, comprising, as it does, so many sudden deaths by violence or accident, so many veterans, removed too soon, and so many young men whose early departure impoverishes the future, even more than the present. Probably, this feeling on my part is largely due to the circumstance that the increased membership of the Institute necessarily in¬volves an increase of the annual death-list. Probably, also, it is connected with the circumstance that during the first years of the history of the Institute-say from 1871 to 1880-it was joined by men of all ages, and that the death-rate is consequently now above the average which would result from the normal annual addition, principally of young men. And finally, I must admit that, as one of the original members of the Institute, and practically connected with it for nearly thirty-seven years as Acting President, President or Secretary, I am peculiarly impressed and depressed by the successive deaths of those who were my associates in the years of its early struggles and triumphs. I do not wish to inflict upon my younger colleagues the melancholy reflections of an increasingly lonesome old man. In fact, my prevailing mood concerning the Institute is not at all melancholy, but triumphant and hopeful. If I may be permitted to preach at all, I would enforce, from the texts given below, a moral which many of them declare so forcibly as to preclude the necessity of expository enforcements-namely, the duty of every one of us, old or young, to give to his brethren, as he goes along, and without waiting for some future occasion for a comprehensive and monumental contribution to technical literature, the results of his observation and experience. When I look at this list of names, my personal sorrow over many of them is drowned in my professional reflection as to each and all-How much has died with

Jan 1, 1908

By Rita D. Sylvester

"This compilation lists and summarizes publications by Bureau authors published in the regular Bureau of Mines series, in scientific, technical, or trade journals, or in other media; those available from the Bureau of Mines are indicated. Patents issued to Bureau personnel are also listed, and instructions are given on how to apply for permission to use them. One of the outstanding features of this Special Publication is an exhausive subject and author index. IntroductionThe Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and present their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries, The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminar's; in reference books; and in other non-Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable. This issue describes reports and articles published during the period January 1, 1970, to December 31, 1974. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960;2 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960;3 and the 5-year lists of Bureau publications and articles from January I, 1960, to December 31, 1964,4 and from January I, 1965, to December 31, 1969.5 It includes all the material in the four annual lists of Bureau publications and articles from January 1, 1970, to December 31, 1973."

Jan 1, 1975

By Ronald S. Conti

A new U.S. Bureau of Mines 6.8-L ignitability furnace was used to study the thermal autoignitability of dust clouds. This furnace has a quartz window to allow observation of the early stages of the ignition process and to allow measurement of the dust explosion temperature. Thermal ignitability data were obtained for various carbonaceous and metal dust clouds, with particular emphasis on various ranks of coal dusts. One of the reasons for the construction of the new 6.8-L furnace was to evaluate the effect of chamber volume on the measured autoignition temperatures. Therefore, data from the 6.8-L furnace were compared with data measured earlier in a 1.2-L furnace. The conclusion is that the autoignition temperatures measured in the 6.8-L furnace were only slightly lower on average than those from the 1.2-L furnace. These data on the minimum autoignition temperatures of various materials will be useful in analyzing the thermal ignition hazards of dust clouds in the mining industry and other industries that manufacture, process, or use combustible dusts.

Jan 1, 2010

By E. C. Yeager, E. O. Wagner, A. W. Koth, V. F. Parry, J. B. Goodman, D. G. Gernes, W. L. Patty

"In July 1943, the Bureau of Nines received an appropriation to investigate the beneficiation of Minnesota iron ores through the use of lignite. The broad objective was to find a way to link the large deposits of lignite in North Dakota with the low-grade iron ores of Minnesota. It was proposed that sponge iron might be made through new methods of processing, and one of the objectives was to determine the possibilities of gaseous reduction of fine ore. The problem of obtaining high-hydrogen reducing gases from lignite was assigned to the Subbituminous Coal and Lignite Section of the Bureau of Mines in August 1943.Through the advice of technical consultants and men familiar with the mineral resources of Minnesota and North Dakota, a tentative program of development was outlined. The first proposal was to study the gasification of lignite briquets in a standard water-gas machine. Previous experience with gasification of lignite indicated that the raw fuel would not be suitable for use in the conventional water-gas process on account of degradation, but gasification of lignite briquets appeared possible. Through the cooperation of the Northern State Power Co„ a series of tests was made at the company's plant in Grand Forks, N. Dak., on lignite-char briquets made by the Lehigh Briquetting Co. at Dickinson, Dak. These briquets are made by the Lurgi process, and they have been used satisfactorily as a domestic fuel. The object of the tests was to compare gasification properties of lignite-char briquets with those of gas. coke made from Kentucky coal, normally used in the Grand Forks plant. The tests revealed that the lignite-char briquets were not suitable for gasification, in the standard water-gas process because of disinte-gration and low efficiency caused by loss of fine carbon.While these investigations were underway, a joint Minnesota-North Dakota Development Commission was formed to aid in planning investigations on development of mineral resources of the two States. Some members of this commission were technical men, who with consulting engineers on the Bureau's staff made up an unofficial technical committee, and assisted in solving certain problems connected with gasification of lignite and beneficiation of iron ores. This committee has been of 'real assistance in guiding the investigation.A technical meeting was held in Minneapolis on November 10 and 11, 1943, for further discussion of objectives and certain technical problems. Results of tests on lignite briquets were presented, and several reports analyzing other methods of gasification were discussed. The Reyerson-Gernes process for the continuous gasification of lignite in an externally heated retort was considered from several angles. This process differs from others in that the natural moisture in the coal is utilized to help gasify the coal, and the volatile matter is largely decomposed. Although this process had been carried out successfully in a small steel retort, no definite design for a commercial-scale retort had .been developed. It was first proposed that the process might be carried out in a Glover-West retort. However, it was brought out that a Glover-West retort would require modification to simulate the process correctly, and that good results might not be obtained even then owing to the leakage of gas through the refractory walls and to an anticipated low rate of heat transfer at the gasification temperature suitable for lignite. Further, the probable leakage of inert furnace gas into the water-gas would be adverse to the Objective to obtain a gas that could be purified to 96 percent hydrogen."

Jun 1, 1946

During the period January 1, 1977 through July 31, 1977, 5 percent (264,000 tons) of U.S. capacity was closed due to power curtailments in the Pacific Northwest because of the shortage of water. During July, one plant in Tennessee cut production by 50,000 tons annually due to a power reduction by the Tennessee Valley Authority. Full capacity production was resumed at a West Virginia smelter during September. If demand for aluminum is strong it seems likely that aluminum supply during the remainder of 1977 and in 1978 will be tight. The price was increased 3¢ per pound to 51¢ per pound effective March 28, 1977, and by an additional 2¢ per pound to 53¢ per pound, effective July 5, 1977. New projects and expansion of existing facilities are planned by Australian aluminum companies over the next 2 to 3 years. The companies listed have committed themselves to spending approximately A$801 million: Alcoa of Australia Ltd. -New alumina plant at Wagerup, south of Perth. Darling Ranges bauxite is located near the proposed project. A$650 million. Coma 1 co Industries Pty. Ltd. -Increase bauxite mining capacity and upgrade or replace other facilities at its Weipa mines on Cape York Peninsula region of Northern Queensland. A$81 million. Alcan Australia Ltd. -Expansion program that will increase capacity of the Kurri Kurri aluminum smelter north of Sydney about 50 percent, and improvement of other facilities at the plant. A$70 million.

Jan 1, 1977

By Thomas D. Kaufmann

Introduction What drives the price of gold? Supply and demand, of course. But in ways far different from the forces that drive the prices of other major metals, such as steel, aluminum, and copper. Gold, in fact, is one of the few commodities where both buyers and sellers are happy when the price goes up. Current production, production costs, and variations in production have little influence on its price. Gold inventories are so tremendous that current production has small impact on the amounts available to the market at any time. Worldwide gold inventory and production The world's inventories seem to be between 78 and 98 kt (2.5 and 3 billion oz). Since biblical times, the gold miners of the world have produced about 98 kt (3 billion oz), mostly in this century. Only small amounts have been thrown away and most of it - more than 78 kt (2.5 billion oz) - remain in bullion, coins, or jewelry. About 40% is held by central banks and other governmental authorities, 30% by private individuals as bullion or coins, and about 30% as jewelry. Except for some of the jewelry and the few industrial applications, this inventory is constantly available in marketable form at a price. By comparison, gold production is indeed small. The US Bureau of Mines estimates that the world produced 1.5 kt (50 million oz) of gold in 1986. Consequently, production increased world inventories by only 2%. Variations in production have a negligible or very short-term effect on the supply and, consequently, on the markets for gold. Although South Africa mines about 40% to 50% of the world's annual production, continuing labor strife there does not seem to have ruffled gold prices. Determining gold's price Gold prices, however, do determine cutoff grades in the mines and, thus, do influence production. Nonetheless, changes in production have little impact on the inventory supply. Consequently, it has small influence on the price of gold on the market. With a fairly stable supply, price changes are driven by changes in its demand. Unlike other metals, very little of the demand for gold comes from industry. Dental, electronic, and other industrial uses for gold consume less than 46.6 t/a (1.5 million oz per year). It would be safe to assume that such uses are less than 124 t/a (4 million oz per year) for the entire world. Variations in the 124 t (4 million oz), compared to a supply of 78 kt (2.5 billion oz) of supply can have only a negligible effect. Production net of industrial uses adds perhaps 1% annually to world inventories. This could, in time, affect markets. The increase, however, is mostly absorbed by population growth - more people wanting to own gold - and by gold being put in more attractive forms, such as coins. As an ancient Lydian king discovered, minting bullion permits

Jan 9, 1987

Once every three years the eyes of the construction and mining industry?s turn to Munich, Germany for the bauma trade fair and exhibition. From April 19-25, Messe München International (MMI) will host the 29th edition of this massive show that, despite the recent recession and global financial struggles, has grown yet again. The show, which is completely booked, will take place on a record 555,000 m2 (5.9 million sq ft) of indoor and outdoor exhibition space at the New Munich Trade Fair Centre. More than 3,000 exhibitors are expected to make use of this event. To prepare for the show that highlights some of the largest and most impressive construction and mining equipment in the world, Messe München began working months in advance on getting the infrastructure on the open-air site ready, in time for the arrival of the gigantic machinery exhibits, which started to arrive in March. Part of the preparations include a new entrance at the northwest corner of the exhibition center that was built to regulate visitor flow better. This should help with bauma considering that in 2007 more than 500,000 visitors passed through the gates. ?Although in 2010 the construction machinery sector in many markets worldwide will be recovering only slowly from the recession, we are pleased to report that we are seeing strong demand for exhibition space. This shows that exhibitors regard participation in the world?s leading trade fair bauma as a must, although many are at present having to make cuts in their advertising and trade-fair budgets. We have been particularly surprised by the strong demand for space from exhibitors from markets like China, India and Turkey. The fair is fully booked and many more companies are on the waiting list,? said Eugen Egetenmeir, managing director of Messe München. More than 50 percent of the exhibitors at bauma 2010 come from countries outside of Germany. While the show?s primary focus is on the construction section, it is not as if the mining sector will be difficult to find. With some of the largest equipment in world on display in section C2 (Fig. 1), the mining industry is sure to be well-represented.

Jan 4, 2010

By H. Sekimoto, T. Matsuoka, K. Yasuhara, M. Ota, S. Akutagawa

A magnetic anisotropy sensor is used for nondestructive measurement of stress on surfaces of a ferromagnetic material, such as steel. The sensor is built on the principle of the magneto-strictive effect in which changes in magnetic permeability due to deformation of the material is measured in a nondestructive manner, which then can be translated into the absolute values of stresses existing on the surface. This technique was applied to measure stresses of H-beams used in tunnels. The results show that this method could be one of the promising technologies for non-destructive stress measurement for safe construction of underground structures. Une sonde magnétique anisotropique est utilisée pour des mesures non-destructives de stress sur la surface d' unmétal ferromagnétique, comme l'acier. La sonde est construite sur le principe de l'effet magnéto-strictif dans lequel les changements dans la perméabilité magnétique due à la déformation du metal est mesurée avec une manière non-destructive, qui peut être alors traduite en valeurs absolues des stress existants à la surface. Cette technique a été appliquée pour la mesure de stress des poutres en H utilisées dans les tunnels. Les résultats montrent que cette méthode peut être l'une des technologies promet tantes concernant les mesures non-destructives de stress pour des constructions sûres de strcutures souterraines. Ein magnetischer Anisotropie-Sensor wird für die zerstörungsfreie Messung von Spannungen an Oberflächenvon ferromagnetischen Materialien wie z.B. Stahl verwendet. Der Sensor kann Änderungen in der magnetischen Durchlässigkeit auf Grund von Verformungen des Materials erkennen, die dann in Absolutwerte der Spannungen an der Oberfläche umgerechnet werden können. Die Methode wurde auf Messung von Spannungenvon H-Balken in Tunnels angewendet. Ergebnisse zeigen, dass dies eine vielversprechende Methode für diezerstörungefreie Messung im Tiefbau ist.

Jan 1, 2003

By Katherine A. Klein

Refuge chambers may potentially save the lives of miners during a mine emergency. For this reason, it is crucial that miners know how to operate them. Unfortunately, because refuge chambers provide so many services, they can be very complicated and difficult to operate. Therefore, NIOSH has created this document with suggestions for developing manuals and educational materials. A multidisciplinary team comprised of NIOSH engineers, sociologists, psychologists, health communication professionals, and geologists developed the recommendations contained in this document. These recommendations are based on an evaluation of manufacturers? instruction manuals from both the U.S. and globally, interviews with over 20 mining and safety experts, and an extensive literature review. This research, focused on the best practices for refuge chambers, led to the formulation of this document. It is intended to offer suggestions to manufacturers and mine operators on how to create effective and easy-to-understand training manuals for miners as well as tips to create the most comfortable and usable refuge chambers. It should be noted that these recommendations are not meant to substitute for manufacturer-supplied materials but rather to be used in conjunction with manufacturer?s materials. Manufacturers should always be consulted for up-to-date information about their chamber. Although different states and different mines refer to underground refuges by different names, this guide will simply refer to underground refuges nearest to the face as refuge chambers, whether inflatable from a skid or constructed from steel. Other popular terms for refuge chambers are rescue chambers, rescue shelters, and refuge shelters. Refuges that are nearer to the shaft, whether a prefabricated refuge chamber or one built into a crosscut, will be referred to as outby refuges because of their location in the mine. Outby refuges can be permanent, semipermanent, or portable and are usually located at every other SCSR cache. Outby refuges are sometimes called hardened rooms, outby shelters, and in-place shelters. When discussing outby refuges and refuge chambers collectively, this guide will refer to them as underground refuges. Other terms for underground refuges include refuge alternatives, locations of safety, and safe havens. This document is designed to be read either cover to cover or by specific section. It is recommended that on first read, this guide be read cover to cover. In subsequent readings, manufacturers and mine operators may find it easier to use the table of contents page to locate specific information on parts of the refuge chamber.

Jan 1, 2009

By C. Yi, M. Onifade, B. Genc, S. Dineva, T. Zvarivadza, M. Khandelwal

Deep hardrock mines worldwide increasingly face rockbursts as mining depths increase. These events result from the accumulation and sudden release of stress, causing rockmass damage and posing major safety and operational challenges. This paper focuses on destress blasting as a critical strategy to mitigate rockburst hazards. Although limited practical experience exists in Swedish deep hardrock mines, international case studies demonstrate that, when well implemented, destress blasting redistributes peak stresses by promoting controlled fracturing around mining excavations. The success of such techniques is highly dependent on site-specific factors such as stress regime, rockmass brittleness, structural geology, and blast layout. Although destress blasting is especially effective in massive, brittle rock under high stress, typical conditions for strainburst prone environments, its design cannot rely solely on numerical models. Simulations can offer preliminary evaluation of stress redistribution trends and guide early design assessments but their current limitations, including sensitivity to input data and simplified fracture mechanics, mean they are best used as supplementary tools rather than final decision-makers. Field trials, supported by microseismic analysis and fracture mapping, remain essential for validation. The study critically synthesises international experiences and presents a structured framework for destress blasting design, offering practical and academic perspectives aligned with Swedish geological conditions to support safer and more efficient application in deep hardrock mines.

Jun 27, 2025

By J. D. Davis

THIS-report gives results of in investigation of the carbonizing properties of 18 coals, including 2 from Alaska, 12 from British Columbia, 3 from Washington, and 1 from Utah. Each coal was carbonized in the standard 13-inch Bureau of Mines-American Gas Association (BM-AGA) retort at 900° C. Plastic properties were determined by the Gieseler and Davis methods, and agglutinating and free-swelling properties were determined by standard methods. Expanding properties were measured in the Bureau of Mines sole-heated oven. From the results of the tests on these single coals, three coals from the Crowsnest area in British Columbia, representing Elk River Nos. 4, 9, and 10, were selected for blending with the Utah coal, which was from the Lower Sunnyside bed, Horse Canyon mine, Emery County. Lower Sunnyside also was blended with Wilkeson -Nos. 2 and 3 (Washington) coals, Pocahontas No. 3 from McDowell County, W. Va., and the Oklahoma low-volatile coal used in the blend carbonized at, the Provo, (Utah) coke plant at the time this investigation was started. Most of the blends contained 3 percent hard pitch, which is the proportion used at the Provo plant. The blends were also carbonized in 13-inch BM AGA retorts at 900° C. High-volatile B coal from the No. 3 bed, Evan-Jones mine, Lower Matanuska, Valley, Alaska, yielded poorly fused coke or char. M-bed coal from the Chickaloon mine, Upper Matanuska. Valley, Alaska, ranked as medium-volatile bituminous and coked strongly. It expanded 39.6 percent in the sole-heated oven at a. charge density of 55.5 pounds per cubic foot..

Jan 1, 1952

By E. G. King

The Bureau of Mines made experimental determinations of the heats of formation of forsterite and chrysotile at 298.15° K. The heat capacities of two polymorphs of serpentine, chrysotile and antigorite, were measured over the temperature range from 50° to 298° K and the entropies at 298.15° K were evaluated. The heat content of antigorite above 298.15° K was measured to 850° K. These thermochemical data were combined with other pertinent data to give heat and free energy of formation values at high temperatures. Free energy values are given for the reaction, forsterite + water = brucite + serpentine at different temperatures and pressures.

Jan 1, 1967

By Branch of Editorial Services

"The Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau of Mines to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable. This issue of the Bureau of Mines List of Publications and Articles describes reports and articles published during the period January 1, 1980, to December 31, 1984. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960;1 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960;2 the 5-year lists of publications and articles from January 1, 1960, to December 31, 1964,3 from January 1, 1965, to December 31, 1969,4 from January 1, 1970, to December 31, 1974,5 and from January 1, 1975, to December 31, 1979;6 and the annual lists of Bureau publications and articles from January 1 to December 31, 1980,7 from January 1 to December 31, 1981,8 from January 1 to December 31, 1982,9 and from January 1 to December 31, 1983. 10"

Jan 1, 1985