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By G. S. Scott

Safety problems in the mining and allied industries have led the Bureau of Mines to investigate over a period of years; the flammability (explosibility) of many types of combustible atmospheres principally at ordinary pressure; the results of these investigations have been made available as a bulletin. However, more recently, the demand for information on the flammability of gaseous mixtures at high and low pressures has increased greatly. In particular, the rapid development of high-altitude aviation has brought demands for information on the flammable (or explosive) characteristics of certain gases and liquids at low pressures. The present report gives the results of about 900 tests made to determine the flammability of the lighter paraffin hydrocarbons mixed with air and nitrogen at pressures of 400 200, 100 and 70 ram. Hg. The gases tested include natural gas, methane, ethane, propane normal butane and isobutane. The minimum pressures at which these gases are capable of propagating flame whorl individually mixed with air also were investigated.

Jan 1, 1952

By CADEN VITTI, Barbara J. Arnold

Mine tailings, the byproduct of mining and mineral processing, are increasingly mass-produced as a result of increased demand for metals and minerals as well as the advancement in technology that allows for the exploitation of lower-grade ores. Lower grades can increase the volume of tailings that may contain new gangue minerals that should be evaluated for the presence of critical minerals and other valuable metals. The practice of reprocessing, while relatively new, is crucial to reducing environmental damages, obtaining valuable critical minerals from waste, and contributing to more sustainable repurposing and disposal methods. With the increase in tailings dam failures in recent years, there is a large motivating factor in remining and removing the potential hazard to benefit the safety of potentially impacted communities. In analyzing the perspectives of various domestic and international studies, this literature review will determine the feasibility of reprocessing and reutilizing mine tailings waste for a more sustainable future while exploring current practices that have benefitted ecosystems and communities.

By I. Cerny, M. Vanek, J. Hubácek

"SWOT analyses and the closely related TOWS matrix are frequent starting points for an organization to develop its strategy. The paper deals with the evaluation of the TOWS matrix and presents three novel approaches to evaluate the different factors of the TOWS matrix, namely (1) approach to evaluate the factors with identical weights; (2) approach to evaluate factors with their weights determined within the different quadrants of the TOWS matrix; and (3) approach to evaluate factors with weights determined within the whole TOWS matrix. The third approach has two variants. The proposed approaches to evaluate the TOWS matrix were tested on a SWOT analysis of a significant mining company in the Czech Republic. The results imply that the strategy W-T (weaknesses-threats) is recommended in three cases, while the strategy S-T (strengths-threats) is recommended once. The paper may be valuable for managers responsible for strategic planning.IntroductionThe process of human needs gratification has been closely connected with raw material resources of the planet. In the contemporary socio-economic conditions, the task of the mining company managers, apart from extracting mineral resources, is to meet the owners' intents.The managerial work itself becomes very complex. In mining companies in particular, the complexity is augmented by the characteristics of the business. Undoubtedly, the key factor is that mineral resources cannot be renewed or relocated. Stojanovi (2013) characterizes mining projects as involving great investments in finance and time, as well as consecutive decisions and a 'complex mosaic of numerous unknown factors that affect the value of the project'. He adds that mining projects are typified by a 'number of geological, technological, technical, economic, environmental, social, and financial risks' (Stojanovi , 2013).Inter alia, the managerial work may also be intese due to the dynamic internal and external conditions for the existence of any company (Vane? k, 2014). This tallies with Peter Drucker’s prediction in 1969; that the times at the turn of the millennium could be expected to be turbulent (Drucker, 1969)."

Dec 1, 2018

By D. T. Randall

The burning of coal without smoke is a problem that concerns the Government directly because of the advantages of smokeless combustion both in public buildings and on naval vessels. In addition, smoke abatement is a factor in conserving the fuel resources of the United States. Hence, as part of its general investigation of the best methods of utilizing the coals of this country, the Bureau of Mines, which is in charge of the fuel-testing work formerly carried on by the United States Geological Survey, has made extended tests to determine the conditions necessary for the smokeless combustion of bituminous coal in boiler furnaces. Bulletin 39,¢ a preliminary report, treats the smoke problem from a theoretical point of view, detailing the steps that are being taken by municipalities, manufacturers, and citizens to abate smoke, also showing the possibility of a clean city. The present bulletin not only shows that bituminous coals high in volatile matter can be burned without smoke, but also that large plants carrying loads that fluctuate widely, where boilers over banked fires must be put into service quickly and fires forced to the capacity of their units, can be operated without producing smoke that is objectionable. Proper equipment, efficient labor, and intelligent supervision are the necessary factors.

Jan 1, 1918

By N. Mashaba, D. Botha

The aims of this study were to investigate the factors that influence women’s engagement in technical positions in the South African mining sector and to determine what could be done to promote their successful participation. A convergent parallel mixed-methods research design was used to ascertain the factors that facilitate, inhibit, and influence engagement. In the quantitative phase of the study, questionnaires were circulated to women employeees; and in the qualitative phase, semistructured interviews were conducted with employer representatives, most of whom were human resource personnel. Confirmatory factor analysis showed that the three-factor structure (vigour, dedication, and absorption) of the Utrecht Work Engagement Scale fit the sample data reasonably well. Although there is room for improvement, respondents demonstrated acceptable levels of engagement in their work. On the other hand, the qualitative findings showed that employee engagement is impacted by unfavourable working conditions, work–life balance, and the mining industry’s male-dominated work culture. The findings showed that employee engagement should be elevated to a core human resource function. To increase the participation of women in mining, human resource professionals are encouraged to collaborate with mine supervisors, managers, and employees to develop programmes that promote employees’ absorption in and dedication to their work.

Nov 6, 2023

By Henry Kreisinger, WALTER T. RAY

This preliminary bulletin was written as the first of a series of several on the significance of drafts in steam-boiler practice, the succeeding bulletins to be along the same lines but of a more advanced character. The conclusions arrived at are tentative, and are the result of a study of one of the many problems growing out of a general plan of the United States Government to increase the efficiency with which the coals of the country are being used. Greater efficiency requires better boiler and furnace design. The experimental study of drafts on which the conclusions presented in this bulletin are based formed part of the fuel-testing investigations that were carried on by the technologic branch of the United States Geological Survey and have been transferred to the Bureau of Mines. The experiments made seem to indicate that it is possible to double or treble the capacity of a plant without making any radical changes the furnaces and boilers. These increases require about double and treble the quantities of air to be put through the fuel beds and boilers. It also seems probable that rebafHing the boilers will often permit the capacity to be doubled or trebled, while still getting more steam than formerly per pound of coal for uses outside the boiler room. These experiments were undertaken with the object of clarifying ideas concerning the passage of air through fuel beds and boilers. Measured weights of air were passed through two beds of lead shot, series, one of which remained always the same and represented a boiler; the other being varied as to size of shot and depth of bed, and representing a fuel bed. Careful observations were made of the weight of air passing through the beds per minute. All data were plotted in many charts, so as to permit the study of them from several points of view. A number of laws were deduced bearing on the relative amounts of power required to force air through fuel beds of various thicknesses, composed of various sizes of coal, and through boilers of various lengths and areas of gas passages. An important part of the discussion relates to an increase in the capacity of boilers by increasing the amount of power applied to pressure and exhausting fans and thus forcing several times as much air through the fuel beds and boilers. may be possible, as a result of these investigations, to raise the rate of working the boiler heating surface to three or even four times its present value. Such an increase would undoubtedly mean new designs of grates, stokers, furnaces, and boilers, especially fitted for high rates of working. Fan equipments designed to supply three or four times as much air under several times the pressure would be provided with more efficient engines, thus giving an additional factor favoring high-capacity working. It must be borne in mind, as stated above, that the results are tentative. It will cost money to force gases at high speeds through fuel beds and boilers, and there will soon be pressing need of such quantitative data as will enable the largest possible part of the energy imparted by the fans to be advantageously utilized. We desire, to thank our superiors, especially Messrs. L. P. Breckenridge and D. T. Randall, for their helpful criticism and suggestions.

Jan 1, 1911

By Snehamoy Chatterjee, Dharmasai Eshwar, Aref Majdara, Rennie Kaunda, HUGH MILLER

The U.S. mining industry has made progress in reducing accidents and injuries, but interpreting safety data remains difficult due to changes in workforce size and productivity. The Mine Safety and Health Administration (MSHA) uses tools like the pattern of violation (POV) and significant & substantial (S&S) calculator to monitor safety, though these have limitations. To address this, we developed an information entropybased risk (IER) index that combines various safety metrics, including citations, penalties and injuries. Using data from 2011 to 2020, the IER index was validated with statistical methods and clustering algorithms to ensure it accurately reflects risk levels. The analysis showed clear differences in risk across mining sites, proving the index’s usefulness. The IER index was then applied to a coal mine to demonstrate its effectiveness. This new tool can help mining companies better assess their safety risks and take action to improve workplace safety.

Nov 1, 2024

By H Arvidson, A Walker, N Pollock

Following the recent tailings tragedy in Brumadinho, the Investor Mining and Tailings Safety Initiative was formed representing institutional investors in the mining industry. This Initiative, led by The Church of England (CoE), requested data from 726 mining companies on each of their Tailings Storage Facilities (TSFs). What this exercise confirmed was that there was no public database of TSFs, and that there was a clear gap in tailings management systems within the disclosing companies. We present an approach using technology to support best practice TSF management, governance and disclosure which was originally submitted as part of University of Cambridge Post-graduate studies in Sustainability Leadership in January 2020. The aim of the paper is to discuss how technology could be used to deliver a Tailings Management Solution (TMS) that is aligned with the Global Industry Standard on Tailings Management (GISTM), and supports rigorous governance leading to disclosure. Subsequently the goals of the plan are aligned with that of the co-conveners of the GISTM (the International Council on Mining and Metals (ICMM), Principles for Responsible Investment (PRI) and United Nations Environment Program (UNEP)) which is to facilitate operators’ trajectory towards zero harm to people and the environment. Most of the focus to date around tailings management post Brumadinho has been on monitoring technologies, of which there are many. It is obviously important to acknowledge the critical role of monitoring technologies; however, our approach is agnostic to monitoring technologies and assumes that all of them are relevant. Our focus is on the data management, reporting and governance leading to disclosure of the information. Critical components of developing the TMS include adapting existing software products and solutions, recognising a system thinking approach is needed, strategic partnerships to deliver an accessible solution faster and more cost effectively, and, new ways of collaborating. The TMS should also accommodate relevant regional geotechnical codes and standards. The industry need for a TMS is well established and urgent, with significant pressure from regulators and civil society for the industry to address this significant issue.

Jul 1, 2021

Research on alternative lixiviants for gold is ongoing; however few people have looked at complete flowsheets. Alternative lixiviants are typically applied at concentrations 50 to 100 times those required for cyanidation. The higher concentrations make lixiviant recycle a vital part of the process. In addition it is no longer feasible to rely on lixiviant destruction to produce lixiviant free clean water for recycle to the comminution circuit. Ausenco has worked with Barrick to integrate reverse osmosis into the thiosulfate RIL processing flowsheet that forms the basis of the plant upgrade currently being constructed at Barrick’s Goldstrike autoclave facility.

Jan 1, 2014

By Christopher Mark

Sixty years ago, underground coal mining was the most hazardous job in the United States. Roof falls were a big part of the problem. They killed about 100 miners every year, more than all other causes put together. Fast forward half a century to 2016, which is the first year ever with zero roof fall fatalities. Just three miners were killed by roof falls during the following 6 years. How was this historic goal achieved? This paper starts with a modern analysis of the causes of the roof fall fatalities in 1968. Then it follows the reductions over time by category, using snapshots of the fatalities occurring in subsequent decades. Along the way, it evaluates the influence of the regulatory environment, changing mining methods, and better ground control technology. The paper shows that in 1968, more than half of roof fall fatalities at large mines were attributable to an inadequate safety culture. The immediate effect of the 1969 Coal Mine Health and Safety Act was to reduce the riskiest activities, like needlessly going under unsupported roof. Other hazards, like large roof falls, required technological developments before they were brought under control. Roof control plans, which the U.S. Bureau of Mines had been advocating since the 1920s, played a significant role throughout the process.

Jul 1, 2023

By S. L. Windes

"INTRODUCTION For a number of years, the Bureau of Mines conducted tests on various types of structures to ascertain the effect of seismic vibrations emanating from quarry blasting in an effort to determine an index of damage. Associat¬ed with these tests, occasional records were made of the characteristics of the air blast or concussion from the explosions. Although the importance of the air-blast problem was recognized, the equipment was not designed for airblast measurements, nor was the early research program concerned with the problem. After the ground-vibration tests had been completed, attention was turned to study of the air blast and its effect. The program was modified, however, in certain aspects by the imminence of war and the final entry of the United States into the conflict. These modifications were made to supply information pertaining to military and civilian defense problems.Detailed discussion of these problems is beyond the scope of this report, which attempts to present preliminary results of factual and fundamental character. However, it may be noted that airblast data are urgently needed for intelligent design of both Government and non-Government buildings, which must withstand the air blast from bombs and afford maximum protection for the occupants. The safety of vital equipment above and below ground necessitates consideration of damage from air blast. Protection against use of dynamite by saboteurs, moreover, hinges largely on the effect of air blast. Identification of a planned ""accident"" involving dynamite often entails knowledge of the characteristics and power of the airblast.The peacetime problem of damage from air blast resulting from quarry and mining blasting activities is of course exaggerated by the wartime requirements of increased production accelerated operation, and enlarged development."

Jun 1, 1943

By A De, B Palmer, rade, P Stowasser, A Fanning

Mining and tunnelling share many commonalities (eg confined working environments, excavation equipment and processes), but of significance is an overarching commitment to provide safe work conditions and environments. This includes reducing exposure to hazardous airborne contaminants such as dust and fumes, in particular Respirable Crystalline Silica (RCS) and Diesel Particulate Matter (DPM), with methods that are environmentally sustainable. In mining, wet methods are common to suppress airborne contaminants, however these methods are reliant on water availability, can be less effective for respirable dust, can have implications for environmental water contamination and can increase maintenance on mining equipment. In contrast, the use of dust scrubbers that provide filtration of airborne contaminants are well established in the tunnelling industry and frequently used to provide spot extraction (dust control at the source) and act often as a complement to the main ventilation system. This paper sought to learn more about the advancements in tunnelling that could be readily applied to mining to improve health outcomes. The paper includes a review of literature and legislation related to health and sustainability and interviews with three respected, and experienced managers from the global tunnel construction industry. It is from these interviews that the focus of the paper turns to Sydney’s WestConnex underground tunnel network and the success of stage 3A M4-M5 construction link. The findings position dust scrubbers as integral to the overall project success as they enabled a Tunnel Production Line (TPL), where multiple stages of construction could take place simultaneously by controlling high volumes of dust at the source. The findings also suggest efficiencies of using mobile scrubbers, both track mounted and hydraulic stepping systems, to accompany road headers and other equipment throughout the excavation process. The findings have transferable applications to underground mining processes in which workers are exposed to high volumes of dust (eg drill and blast) or situations in which dust control at the source, mobility and flexibility offer value (eg room and pillar mining).

Apr 16, 2024

By E. D. Gardner

Placer mining is the mining and treatment of alluvial deposits for the recovery, of their valuable minerals. The method has been used principally for mining gold, but a large proportion of the world's production of tin, platinum, and diamonds and other gem stones and minor quantities of other heavy minerals have been won in this manner. In the United States, as in the world at large, gold has been the principal mineral obtained by placer mining. Minor quantities of metals of the platinum group are recovered with the gold in some localities. Important quantities of sapphires have been produced at placer mines in Montana, and tungsten minerals have been obtained on a commercial scale from placer deposits in California and Colorado. Other heavy minerals or gem stones, however, have not been mined to any important extent by this method in the United States. The search for placer gold and the working of the deposits when found have had much to do with the early development of the West. Placer mining has been gradually overtaken and surpassed in importance by lode-gold mining, until in 1932 less than a quarter of the country's total gold production was from placers or about an eighth, excluding Alaska. In 1932 about 76 percent of the placer gold produced in the United States was recovered by dredging. Although other forms of placer mining still are important, they have been declining for many years, as the richest and most readily mined deposits of gravel along the stream courses have been exhausted. During 1931 and 1932 there was a revival of small-scale mining, but few new deposits were discovered.

Jan 1, 1934

By Brian Y. Lattimer, Kray D. Luxbacher, Jonathan L. Hodges, Manuel J. Barros-Daza

The abstract discusses the importance of predicting fire response time (the time before conditions become untenable for firefighters) in underground coal mines. It introduces a data-driven approach using artificial neural networks (ANNs) to predict response time and fire size based on measurable parameters like CO concentration, mine geometry, air velocity, and time since fire detection. The approach was tested using simulations from fire models (FDS and FSSIM), showing promising results for real-time predictions during mine fires.

Mar 6, 2022

By G. R. Hopkins

According to reports received by the Bureau of Mines, Department of the Interior, as of January 1, 1934, there were 591 completed refineries in the United States, an increase of 86 ever the total reported at the beginning of 1933 and the largest total ever recorded. It should be noted that the 1934 total, although large, probably does not include more than half of the "pot-still" plants of 1 barrel to 50 barrels daily capacity which have sprung up within the last 2 or 3 years and about which very little information is available. However, the combined operations of these snail refineries are of negligible importance as altogether they refine less crude than one plant of average size. Of the completed plants, 454 were operating on January 1, 1934 and 137 were shut down. In addition, 13 refineries were under construction on January 1, 1934. Compared with the previous year these data indicate a marked increase in the number of operating plants, little change in the number of inoperative plants, but a decline in' the number being built. The material gain in the number of operating plants resulted primarily from the construction off approximately 25 refineries, averaging about 100 barrels capacity in the Kooky Mountain district, as well as from the addition of about 20 plants in the East Texas field.

Jan 1, 1934

By Bernd Hagenah, Katie Theis, Cristina Lauzon, Petr Pospisil

Lidding over or tunneling existing transportation infrastructure is currently under review in several U.S. cities. The main reasons for this are the use of the created space for urban development, the reduction of noise and exhaust fumes for the residents, and, thus, a significant increase in the quality of life. The main aspects to be considered during the planning process are (1) total investment and operational costs, (2) impact of construction works on current traffic, (3) safety and fire protection, and (4) socio-environmental issues. The paper presents some basic planning principles, and experiences of recent urban highway coverages are shared.

Jun 23, 2024

By Bernard Lewis

During the past 10 years the technical investigations conducted by the Explosives Division of the Mine and Explosives Bureau of the Bureau of Mines have been described in a series of summarizing reports prepared by Wilbur I. Huff, consulting explosives chemist of the Bureau. These reports covered the…

Dec 1, 1947

By M. F. Almeida

"Due to the randomness of all factors influencing the sintering operation, a two-stepped procedure is proposed to find the best way of using stocked fines at a plant producing Fe-Mn alloys for the steelmaking industry. The approach is based on the following: (1) predict the result of the sintering operation by establishing the best multilinear regression model using some of the characteristics of the loaded material; and (2) find the best solution under a minimizing cost criteria by solving a linear optimization problem using the regression equation plus constraints on the feed and product. IntroductionSome tests carried out using 20% to 30% of sinter in the material loaded into a 60 000 KVA Tysland-Hole electric furnace producing Fe-Mn alloys for the steelmaking industry indicated: (1) a meaningful decrease in the off-gas temperature and, consequently, a better energy use due to the material higher porosity; (2) more uniform heat distribution as a consequence of the electrode reaction zone enlargement; (3) an improved furnace control resulting in a smoother operation; and (4) a decrease in gas production facilitating the off-gas treatment. For some years, this plant used only the coarse fraction of the Mn ores, thus stocking all the received and own-generated fine particles. In view of the mentioned results, a strategy for increasing the use of stocked fines was formulated, including a step where it was necessary to decide which components and respective quantities should be used in the blends to be sintered (Almeida, 1984).It is well known that several factors affect productivity and energy consumption in sinter production, also influencing the product quality. Raw materials characteristics, namely chemical and size composition, affect permeability to gases and may or may not allow a deeper bed. In general, finer ores decrease permeability, increasing electricity consumption by fans, but due to their higher specific surface area, react more completely with other components in the mixture. For coke granulometry, a compromise must be obtained in order not to burn it too quickly nor to widen the flame front, therefore decreasing productivity. Decreasing coke in the blend also acts in sinter bonding, decreasing its consistency and increasing crushing and return fines. Moisture addition also influences components mixing, pre-agglomeration, bed permeability and, consequently, sintering productivity. Therefore, optimum conditions must be established for both a given sintering plant and the components in the feed (Dawson, 1993)."

Jan 1, 1998

By Justin Carl, Aliuddin Mohammad, Gordon Evans, Steven Bealby, Carlton Ray

"The District of Columbia Water and Sewer Authority (DC Water) is implementing the $2.2-billion DC Clean Rivers Project (DCCR) to control combined sewer overflows (CSO) to the Anacostia and Potomac rivers and Rock Creek, and to provide flood relief to the Bloomingdale and LeDroit Park neighborhoods in the District of Columbia. The long-term control plan complies with the requirements of a Federal Consent Decree entered into by DC Water, the District of Columbia and the United States, as represented by the U.S. Environmental Protection Agency and the Department of Justice. The Northeast Boundary Tunnel, a design-build project, will store combined sewage and deliver it to a system of downstream tunnels and ultimately to the Blue Plains Advanced Wastewater Treatment Plant (Blue Plains), where it will be treated. In addition, the Northeast Boundary Tunnel (NEBT) is a major project associated with the mayor’s task force to alleviate extreme flood events in Bloomingdale and LeDroit Park. The Northeast Boundary Tunnel Utility Relocations (NEBTUR) design-bid-build (DBB) project is an accelerated component of the Anacostia River System, as shown in Fig. 1. During dry weather conditions, the entirety of the sewage in the combined system is conveyed to Blue Plains.During storm events, when sewer pipe capacity is exceeded, the flow, which is a mixture of sewage and stormwater runoff, overflows into receiving waters through outfalls. There are a total of 47 active CSO outfalls along district waterways.The influx of storm runoff into the combined sewer has an additional impact on the communities of Bloomingdale and LeDroit Park. The sewer system is outdated and undersized. In these neighborhoods, when the capacity of the sewer is exceeded, localized flooding occurs and backups into adjacent residences are prevalent. In any given year, there is a 50-percent chance that flooding will occur in these neighborhoods."

Jan 9, 2017

It is probably safe to say that, as the economic well-being of the mining industry goes, so goes the fortunes of mineral explorationists. And in 1977 the industry was not well at all. The year-long depression of the copper industry, marked by layoffs, temporary shutdowns, and mine closures, provided an appropriate background for the collapse of the nickel market, passage of a surface mining law that will affect the hard-rock industry in ways that are yet unclear, and the threat of operating under a new set of rules brought on by reform of the Mining Law of 1872.

Jan 5, 1978