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By G. Laird, N. B. Gray, N. Lawson

"Photographic, video, laser, hot film and conductivity methods are used in the experimental study of gas-liquid flows. A discussion of their capabilities and limitations are given in this paper illustrating the wide range of phenomena that can be studied. Most of these methods are limited to physical models at room temperature with transparent fluids, although they can be extended for use with opaque and hot fluids. A number of these techniques have been used by the GKW CRC in studies on industrial plants and their usage is increasing although a number of technical difficulties still need to be overcome. An in-depth discussion of the laser doppler anemometry (LDA) and particle image velocimetry (PIV) methods is given with experimental results on the flow field of an air plume in water based on advanced development of the techniques and studies carried out at the GKW CRC. The LDA method provides high resolution data on the velocity profiles, while the PIV method provides an overall view of the complex flow structure occurring at the gas-liquid regions. These two methods complement each other in providing experimental data for validating numerical models and exploring the complexities of multi phase flows.IntroductionThe injection of gases into melts is an important operation in the metallurgical industry. It is used in converters, anode furnaces, blast furnaces, ladles, bath smelters, zinc fumers and many other smelting processes. In many of these processes, the gas is injected into a molten bath resulting in the formation of bubbles that promote reaction, mixing, alloying and heat transfer. The study of gas-liquid systems presents enormous challenges to the researcher due to the complexity of the mathematical and physical modelling which require innovative numerical and experimental skills."

Jan 1, 1996

By Armine F. Banfield

The Purpose of the Paper It is fitting that the first paper of a session on the Financial Aspects of Mining should be on the basic data upon which any financial discussion of a mining project must be based. The history of a mining project starts with exploration in an area considered geologically favorable for mineralization and culminates in the discovery of a body of valuable mineral material commonly known as a mineral deposit. Subsequently more detailed exploration establishes the approximate size, shape, tonnage and average grade of the deposit by surface and/or underground drilling, -surface trenching and/or underground workings. Some preliminary metallurgical testing and other studies, as required, are made at this time. Development work is then carried out to provide representative samples for determining flowsheet and metallurgical balances, preparing the deposit for production and establishing more firmly the grade and mining characteristics of the deposit. A feasibility study is then made of the engineering aspects of the project including the estimation of operating coats, the capital required to place the deposit into production, profit and return on investment. A valuation of the deposit

Jan 1, 1972

THIS bulletin presents all analytical and lest methods regularly used by Bureau of Mines laboratories for characterizing coal and coke. To provide better service to coal producers and consumers, the scope of this bulletin has been expanded to include important test methods used to evaluate coal properties for commercial processing. The methods described will prove valuable to all persons interested in analyzing and testing coal and coke.

Jan 1, 1967

By Oliver Bowles

Cementing materials of mineral origin were well known to the ancients. Ordinary lime and gypsum plasters were the first to be recorded by historians. The next development was the discovery that certain limes would set under water, but the hydraulic property was not definitely attributed to the presence of clay in the limestone until many centuries later. The Romans advanced a step nearer to modern cement in the development of 'pozzuolana', a mixture of volcanic ash or trass with hydrated lime. The silicate of aluminium in the volcanic rock combined readily with the lime, forming a hydraulic mortar or cement which was widely used. Natural Cement In Europe (1) No further progress was made in the art of manufacturing cement for several centuries, during which the Roman Empire declined and passed away, and the Anglo-Saxon race slowly and painfully evolved through the Middle Ages an ever-increasing prestige. An Englishman, John Smeaton, is credited with the honour of the next important development, for he employed a little-known cementing material-natural cement-in constructing the Eddystone lighthouse in 1756. It was called 'natural' cement because it was made from a natural rock with no additions of other materials. The process consisted of calcining an argillaceous limestone at a comparatively low temperature and grinding the product to a fine powder. Care was exercised to keep the temperature low, and any material burned to the clinkering point was thrown away, although such material was, as learned at a later time, Portland cement.

Jan 1, 1933

By D A. Bowman, S Schafrik

With the goal of reducing injuries and fatalities related to haul truck accidents, this research investigates technologies and intervention strategies for improving worker training using a virtual environment (VE). Funded by the National Institute for Occupational Safety and Health (NIOSH), this research specifically focuses on training workers in preshift inspections of haul trucks to avoid preventable defects from causing worker injuries and expensive equipment damage. Improved training in these inspections is expected to increase uptime. The VE developed to train workers for preshift inspections consists of three phases: the virtual tour, the virtual inspection and the shift simulation. The virtual tour introduces information necessary to conduct a preshift inspection by guiding the worker around a haul truck, identifying parts to be inspected and explaining defects to look for. The virtual inspection assesses retention as the worker navigates around a haul truck and identifies defects. During the shift simulation, the worker is shown a simulation of the work shift, which animates severe consequences of any overlooked defects to emphasise the importance of preshift inspections. To provide multiple training platforms, desktop and CAVEÖ versions of the training VE were created. Flux Studio was used to model the environment and to produce Virtual Reality Modelling Language (VRML) files for the desktop version. DIVERSE, an application programming interface, was then used to implement a more realistic version of the VE in a CAVEÖ, a room-sized visualisation system. Initial feedback from mining colleagues indicates that the training VE may replace normal classroom training for preshift inspections in the future. As opposed to PowerPoint presentations and instructional videos, the training VE provides better spatial understanding of the location of parts and incorporates interactive features to actively engage drivers in the learning process, which may result in better retention. Initial feedback also indicates that minor improvements can be made to the virtual tour and virtual inspection phases.

Jan 1, 2008

By Jack Taggart, Chris Barker

Pile load testing strategies for large infrastructure projects and multi-phase building developments have historically justified cost and programme benefits for undertaking advance preliminary and working pile load testing. However, more recently piling and pile load testing strategies have included assessment of the embodied carbon to understand and present the carbon savings that can also be achieved. This paper gives an overview of the factors contributing to carbon and emissions in the construction of bored pile foundations and presents the methodology taken in assessing embodied carbon as part of the pile load testing strategy for a multi-phased building development in London. Potential embodied carbon savings for various bored pile types and load testing strategies are discussed alongside alternatives and other considerations including pile re-use and carbon offsetting to inform continual improvement for future projects.

May 1, 2022

By F. T. Cawood, T. Chikande, H. R. Phillips

Underground mines require electricity to operate both the main surface fans and auxiliary systems, with primary ventilation systems typically accounting for approximately 40–60% of the mine’s overall electricity consumption. The primary reason for this considerable expense is that most underground ventilation systems are designed for peak demand, regardless of the actual demand, which is commonly dictated by diesel equipment usage in trackless mining operations. Most platinum mines on the Great Dyke in Zimbabwe tend to operate their ventilation systems at this peak level, despite the mine’s air quantity being well in excess of the ‘true’ ventilation needs. This is due to a lack of appropriate ventilation controls. The authors designed and installed a ventilation-on-demand system at one of the bord and pillar platinum mines to minimize the use of redundant air in underground operations. Fourth industrial revolution techniques were applied to the environmental monitoring and tracking systems thereby optimizing air quantity demands. The mine managed to reduce its annual power consumption by 23% through the implementation of manual control and time-of-day scheduling levels of the ventilationon- demand concept. There was also a 6% productivity improvement, mainly attributable to an increased face time as a result of the significant reduction in the re-entry period following a blast. This paper introduces a novel concept of ventilation optimization through digital transformation targeting mainly room and pillar platinum mines. A system was designed, installed, and commissioned, though there is currently an ongoing optimization process to harness the full benefits such as productivity enhancement, reduced power costs, and improved worker health.

Dec 13, 2022

By Robert M. Vadas

Special considerations are described as they apply to the design of ring gears for high-power grinding mills. AGMA requirements, the importance of the supporting structure, material selection and related field experience are discussed, with special emphasis on available and developing manufacturing technologies.

Jan 1, 1978

By G. N. A. Senhorinho, J. A. Scott, C. A. Laamanen

"Closed mine sites are widely regarded as a negative asset due to their legacy of environmental impacts. These sites are often characterized by waterbodies with elevated metal concentrations and low pH that are traditionally considered to have little or no value. These sites are potential sources of beneficial biocompounds produced by microalgae in response to environmental stresses. A bio¬prospecting program found that certain microalgae from waterbodies near historical mine sites exhibited higher antibacterial activity than any microalgae previously reported in the literature. There is potential for the mining industry to be involved in examining features such as tailings ponds at mine sites for high-value compounds, including ones that might help mitigate rapidly growing microbial resistance to current antibiotics. ¦ KEYWORDS Antibacterial, Closed mining sites, Metabolites, Microalgae, Stressed environments RÉSUMÉ Les sites miniers clôturés sont généralement considérés comme des actifs négatifs en raison de leurs répercussions sur l’environnement. On trouve souvent sur ces sites des étendues d’eau affichant de fortes concentrations en métaux et un pH faible, généralement considérées comme ayant peu, voire pas de valeur. Ces sites sont des sources potentielles de biocomposants bénéfiques produits par des microalgues en réponse aux perturbations environnementales. Un programme de bioprospection a permis de déterminer que certaines microalgues trouvées dans ces étendues d’eau à proximité de sites miniers historiques présentaient une activité antibactérienne supérieure à celle mentionnée dans toute la docu¬mentation existante. L’industrie minière pourrait bien participer à l’examen de particularités telles que la recherche de composants à haute valeur dans des bassins de décantation des résidus sur des sites miniers, notamment des composants qui pourraient aider à atténuer l’augmentation rapide de la résistance micro¬bienne aux antibiotiques actuels. ¦ MOTS CLÉS antibactérien, environnements perturbés, métabolites, microalgues, sites miniers clôturésINTRODUCTION The mining industry is one of the largest economic drivers in the world. Within Canada, for example, it contributed 2.8% (C$57.6 billion) of the 2016 gross domestic product (Marshall, 2016). Canada also has the highest non-ferrous exploration budget worldwide (Marshall, 2016); therefore, it is likely that mining operations, mine waste disposal, and the number of closed sites will continue to grow in Canada. The environmental impact of mining operations stems from the volume of tailings produced, which can be up to 97–99% of the total volume of ore processed at a mine (Adiansyah, Rosano, Vink, & Keir, 2015). In 2010, mining was the world’s largest industrial producer of waste at a total of 65 billion tonnes: 51 billion tonnes of waste rock (mine overburden) and 14 billion tonnes of tail¬ings (Jones & Boger, 2012)."

Jan 1, 2019

By Noel Jarrett

Energy consumption and distribution in aluminum production, conservation accomplishments, and future goals are presented. Electrolysis and electrode manufacture show the greatest promise for major improvements. Means are proposed for reducing waste heat generation in smelting and for conserving energy in anode manufacture by furnace design and substitution of other materials for petroleum coke. Hall-Heroult Process modifications, alternative designs, and the Alcoa Smelting Process are discussed as energy savers. Scrap recycling, more use of aluminum in transportation, and the installation of offshore smelters in less developed countries are shown to be additional means of coping with possible energy dislocations.

Jan 1, 1981

By Frank J. Perzak

This report describes a U.S. Bureau of Mines study on the hazards of large-scale conveyor belt fires in underground coal mines, as a function of both air velocity and distance from belt surface to gallery roof. The fire hazards considered were smoke obscuration, toxic effects of carbon monoxide (CO), and elevated air temperatures downstream of the fire. All of these hazards scale with the ratio of fire intensity to ventilation airflow. These hazards were all found to be greater at the lower belt-to-roof distance, owing to the greater fire intensities that resulted. The hazards of smoke obscuration and elevated CO levels were greater at lower air velocities. Smoke obscuration was found to be the earliest hazard, reaching critical levels before the stage of belt flame spread. Critical levels of CO and downstream air temperatures were not reached until the later stages of flame spread. Fire growth rates during rapid flame spread were much greater than rates measured during the early stages of belt burning. Data were analyzed to determine the early-warning capability of fire sensors. Smoke sensors provided the earliest warning, followed closely by CO sensors. Thermal sensors did not exhibit any early warning capability.

Jan 1, 2010

By Alexander Filotti, Richard Kalson

"In the last decade, the construction industry has witnessed significant changes in the project delivery systems and contractual relationships between the general contractors (GC) and Deep Foundation Specialty Contractors. The Deep Foundation industry, especially including industry specialty subcontractors, have experienced a significant increase in requests that project risks be transferred through contract documents to subcontractors and suppliers with a decrease in margins for the industry. GCs regularly revise their form subcontracts to take into account recent experiences/contractual trends and newly issued judicial precedent, an exercise that is less frequently undertaken by subcontractors and suppliers. These contradictory trends are at the base of the ethical analysis of subcontracts that comprises the subject matter of this paper. Using contracts as a risk management tool in order to mitigate the general contractor’s risks in the context of dynamic changes in the legislative environment will also be addressed. Furthermore, another possibility for risk mitigation for the industry is to actively promote the introduction of the latest technical developments into the contract documents.CONTRACTS’ ETHICSFor thousands of years, ethics have been a constant presence in our lives and have been debated by different branches of philosophy. In modern times, ethics in business started to be an imperative for the success of a globalized economy.“Ethics are standards by which one should act based on values. Values are code beliefs such as duty, honor, and integrity that motivate attitudes and actions.” (Rumbaugh 2004). Some of these values and actions have been carved in legislation in general and in business legislation in particular. More and more, unethical business practices (e.g., corruption) are identified as the root cause of poverty, underdevelopment, and war around the world. In the context of contract ethics, three aspects are of interest:•,Ethics of contract construction•,Ethics of contracting processes•,Ethics of risk allocation in contracts"

Jan 1, 2016

By A. Blackmore, D. Baker, L. Human

"Mechanical mixing equipment is common in a wide variety of mining, metals and process applications, such as hydrometallurgical reactors, solvent extraction, digestors, and tanks for storage of slurry or hydrocarbons. Computational Fluid Dynamics (CFD) has been applied successfully to single-phase mechanical mixing problems for several decades and is established as a reliable design tool. As computational power and CFD codes have improved over the years, there have been significant advances in modelling capabilities including improved models of turbulence, interaction of rotating and stationary components, multiphase flows, and modelling of free surface interfaces, for example. This paper will provide an overview of the application of CFD to mechanical mixing problems. First, it will review the traditional single phase Multiple Reference Frame (MRF) approach and introduce a range of advanced modelling techniques. Three examples of the application of CFD to industrial mixing problems will be given. It will be demonstrated that CFD is an effective tool for reducing technical risk in design, for identifying the root-cause of mixing problems, and testing modifications to existing operations."

Jan 1, 2015

By D. Harrington

ANNUAL or necessary inspections and investigations of coal mines for various purposes were made possible through the Federal Coal Mine Inspection Act of May 7, 1941, which authorized entry to the Secretary of the Interior through the Bureau of Mines. Primary object of these inspections is to obtain information pertaining to health and safety conditions. Among the purposes for which the data are to be used, are annual reports to Congress, the publication of inspection reports, and the compilation and publication of statistics. The act states that inspections and investigations shall be made by employees of the Bureau of Mines, who shall co-operate with other bureaus of the U. S. Department of the Interior, as well as with the official mine-inspection, safety cr health agencies of the several states and territories. The act specifies that a coal-mine inspector shall have "the basic qualifica-

Jan 1, 1946

By Peijian Zhang, Yansheng Liu, Yuusaku Tominaga

The directions for ventilation control are often given in linguistic styles such as "if the airflow rate measured is small, a high value of rotation on a local fan should be chosen." In order to control the underground climate using a computer instead of a human being, both the reliability of data values measured underground and the application of human recognition of data values are required. The efficiency of data transmission is dependent on a method of checking a signal which is changed by mixing noises resulting from cases of electrical and mechanical damage to cables. In the study, fuzzy reasoning is adopted to choose a checking method for underground conditions from a normally operating state to an emergency. Fuzzy reasoning is applied to control airflow rate under the linguistic control rules given. It is shown that an effective series of linguistic control rules derived by fuzzy-sets theory is available in ventilation control when used in conjunction with an air velocity sensor, a computer and a local fan with thyristor control. Moreover, a system to make an optimum series of linguistic control rules for ventilation control is introduced.

Jan 1, 1987

By D. Lunt

Telfer bulk concentrates typically contain 8% chalcopyrite, 8% chalcocite, 45% pyrite and 80-120 g/t gold. Although very high copper and gold recoveries can be obtained by subjecting the concentrate to a "conventional" high temperature pressure oxidation step followed by copper recovery by solvent extraction and electrowinning, and cyanidation of the leach residue for gold recovery, the cost of lime required for neutralisation and power for oxygen generation was such that the process was uneconomic in terms of operating costs. The challenge therefore was to develop an alternative flowsheet that maximised copper and gold recovery in which the reagent costs were commercially attractive. An additional objective was to reduce the capital cost so that the overall NPV and IRR values would enhance the economic viability of the total project. Following a series of batch and locked cycle testwork programs, supported by Metsim modelling, it was established that the same high levels of overall copper and gold recoveries can be obtained by use of a novel two-stage split leaching circuit in which the chalcocite component is leached in a low temperature (90-110°C) circuit with the chalcopyrite component treated in a high temperature (220-250°C) circuit. This split circuit has a number of advantages, including minimising the required capacity of the high temperature autoclave, as well as reducing the overall lime consumption and simplifying the total process water balance. The paper outlines the basis for the development of the flowsheet and discusses the integration of the leaching stages into the overall circuit.

Jan 1, 2004

By John F. Wiss

A series of controlled experiments was conducted at four surface coal mines to study the effects of certain blast parameters upon the ground and air vibration. Preliminary scale-model blasts were conducted at a quarry to provide basic data. It was found that the amplitudes of the ground and air vibration were controlled by the maximum explosive weight per delay. Either cube root or square root scaling could be used for the seismic amplitudes, and cube root scaling could be used for the overpressure amplitudes. Both amplitudes were not significantly affected by the total charge weight per blast, the attitude of the boreholes, or the charge length or diameter. The overpressure amplitudes were affected by the charge depth, the use of cover over surface detonating cord, and the use of adequate stemming. The length of the delay intervals and the spacing of holes were important in determining' the potential fur reinforcement of the amplitudes in certain directions from the blasts. In downwind directions from the blast, the attenuation of the overpressure with distance decreases. Surface terrain did not significantly affect the overpressure amplitudes within the range investigated. The type of overburden affects the generation of both amplitudes and the propagation of the seismic amplitudes. Spectral analysis of the ground and air vibration is reported. A bibliography of pertinent literature is included as an appendix. A scaled distance of 300 ft/lb1/3 should produce a peak particle velocity of less than 1 ips and an overpressure of less than 128 dB linear peak. For square root scaling, a scaled distance of 75 ft/lbl/2 should limit the ground vibration to less than 1 ips.

Jan 1, 1978

By Henry Kreisinger, L. P. BRECKENRIDGE, WALTER T. RAY

The investigations of fuels conducted by the technologic branch of the United States Geological Survey had their inception at the Louisiana Purchase Exposition in 1904. By an act approved Febru- ary 18, 1904, Congress authorized the work of analyzing and testing at the Louisiana Purchase Exposition the coals and lignites of the United States, under the supervision of the Director of the United States Geological Survey. An appropriation of $30,000 was made for this purpose. In the general deficiency bill dated April 27, 1904, the sum of $30,000 was added to the appropriation. To carry out these investigations the Director of the Geological Survey appointed a committee consisting of E. W. Parker, statistician of the Geological Survey; Joseph A. Holmes, State geologist of North Carolina; and Marius R. Campbell, a geologist of the Geological Survey. Under the first act authorizing this work all of the machinery and coal for the tests was to be furnished the Government free of charge. The buildings containing the testing apparatus were all paid for out of the first appropriation. After the close of the Louisiana Purchase Exposition every Congress made an appropriation for continuing these fuel tests. These subsequent appropriations permitted the purchase of appliances better adapted for the testing work.

Jan 1, 1912

By B. Mishra, W. A. Averill

"The application of various hydrometallurgical, pyrometallurgical and electrochemical processes in the extraction, purification and production of radioactive metals as well as the use of various materials, ego metals and alloys, ceramics, polymers, etc. in the process, construction and handling equipment in the nuclear industry has generated a large stockpile of radioactively contaminated waste material and scrap metal which can not be directly discarded, recycled or considered for long-term storage due to its volume and potential hazards, without the separation of radionuclides. This paper reviews the emerging methods that have been investigated and suggested for dealing with some of these wastes and scrap material.The separation technologies studied for the recovery of radioactive components from the pyrometallurgical and electrochemical processing wastes have been discussed in details with results from some of the recent theoretical and physical modeling work as well as the data obtained from the actual waste treatment. Specific processes shall be described in terms of its advantages and limitations. These emerging separation technologies are being considered by the US Department of Energy as alternatives for dealing with the issues of environmental management [EM] and decontamination and decommissioning [D&D].IntroductionThe high temperature carbothermic or metallothermic smelting reduction methods for metal production are associated with the generation of significant quantity of waste as slags, flue dusts, sludges, residues, effluent salts etc. Certain hydrometallurgical processes also generate lots of aqueous waste due to the inherent nature of the technique. Also, the gas-based reduction processes are not applicable to many stable metal compounds, such as alumina, titania, beryllia, lanthanide and actinide oxides, etc. due to thermodynamic considerations. All these methods cause substantial environmental hazard. There is a need to develop alternative processes which have low waste or ideally a ""zero-waste"" generation.Pyrochemical processes using molten salts provide a unique opportunity for the extraction and refining of many reactive and valuable metals either directly from the beneficiated ore (aluminum, beryllium, neodymium, plutonium, uranium, etc.) or from other process effluent that contain reactive metal compounds. The processes reduce metal compounds electrolytically (A12O 3 and BeCI2) on a carbon anode or by calciothermic reduction (Po, Nd). The by-product, in the latter case, is a calcium oxide saturated halide salt. The waste-treatment to recycle the halide has to be done as a separate step or stored as a contaminated waste. A successful separation technology can provide a new insight to the waste minimization strategy for the nuclear industry."

Jan 1, 1996

By George A. Page, Hewitt Wilson, Vance S. Cartwright

"Purpose of InvestigationThe process of removing solid material from liquid suspensions has been studied at the Northwest Experiment Station, United States Bureau of Mines, in cooperation with the University of Washington, as part of a general program to investigate the dewatering of Pacific Northwest plastic kaolins, which is difficult by ordinary filter-pressing methods. The present paper is a progress report of the work began by Vance S. Cartwright in 1928 and continued in 1931 and 1932. Spray evaporation is believed to be valuable for the following classes or grades of clay and clay mixtures:(1) Highly colloidal, plastic-type clays, which release their mechanically attached water with difficulty; (2) clays prepared for shipment in pulverized or powdered condition; and (3) synthetic, ceramic, porcelain, and tile mixtures prepared as aqueons suspension, dried and pulverized before molding. Dilute suspensions can be dewatered by spray evaporation to produce concen-trated casting slip or plastic clay with a lower water content.The most common dewatering method used in preparing powdered kaolin for the market comprises the following steps: Reduction of the water content by filter-pressing from approximately 75 percent in the thick ""slip"" condition to about 30 percent in the condition; further reduction of the water in the filter-press cakes by heat to about 5 percent; and pulverization of the dried cakes in hammer or dust. These three steps can be simplified to a single process by spray evaporation."

Jan 1, 1935