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THE discussion at the annual meeting of the paper on "Devices for Detecting Dangerous Gases in Mine Air" (published in. MINING AND METAL-LURGY, February 1, 1927, p. 69) was prefaced by the following description of a new portable methane indi-cator, presented by D. C. Ashmead: Two comparatively recent disasters in Utah are directly responsible for the perfection of the new methane detector. The first of these occurred on May 1, 1900, when 200 work-men lost their lives. The second disaster did not occur for more than two decades, when, on March 8, 1924, at the Castle Gate Mine No. 2, 172 workmen were killed. A dis-sembled safety lamp was later found at the seat of the ex-plosion. This indicated, as a possible cause, that the safety lamp had gone out and the fire boss had tried to relight it. These two disasters brought, the mine operators of the State of Utah to the concentrated attempt to end the loss of life through mine explosions. The Governor of the State appointed a committee, known as the Utah Mine Op-erators Committee, to study the phases of the problem, and this Committee in turn enlisted scientists all over the country in cooperative research. One group, under the direction of E. K. Judd, of the Union Carbide and Carbon Research Laboratories, of Long Island City, New York, concentrated its efforts on develop-ing a methane detector which would be completely ade-quate. This is now successful, since in laboratory as well as actual coal-mine tests the apparatus has instantaneously and accurately detected the presence of extremely small amounts of methane.

Jan 3, 1927

By A. S. Haugh

OHSAS 18001 is a series of international standards for occupational health and safety management. It is comprised of two parts, 18001 and 180029. OHSAS 18001 was formulated by international certifying bodies and is based on BS8800 and was first published in 19996,11. OHSAS 18001 was developed to be compatible with ISO 9001 and ISO 14001 in order to facilitate integration of quality, environment, and occupational health and safety management systems5. It is a voluntary standard and the overall aim of OHSAS 18001 is to enable organizations to control their occupational health and safety (OH&S) risks and improve overall health and safety performance5. OHSAS 18001 is widely accepted in the UK, Europe, and Asia, is gaining momentum in North and South America, and it was used as the basis and conforms to the requirements of ANSI/AIHA Z.10-2005: American National Standard for Occupational Health and Safety Management Systems. It defines a set of requirements for an occupational health and safety management system suitable for any kind and size of organization4. Businesses of all sizes are developing and implementing occupational health and safety management systems (OHSMS) that are in compliance with the OHSAS 18001 standard.

Jan 1, 2012

John Birkinbine, Philadelphia, Pa.: We have in the Institute two Dudleys—Dr. Charles B. Dudley, who has so thoroughly studied the chemical composition and physical behavior of rail-steel, and Dr. P. H. Dudley, whose investigations and

Jan 1, 1900

By Klaus Pronold

Once installed rolling mills can look forward to a long life. Around 40% of the 140 conventional hot strip mills presently in operation were built between 1960 and 1970. 17 of the 29 CSP®-plants were commissioned before the year 2000 and have automation platforms that are obsolete and/or have outdated rolling technology. Keeping pace with the market requirements is an ongoing challenge for producers of flat steel. It is a real balancing act keeping production facilities performing at necessary levels, safeguarding the investment and keeping outage periods to a minimum. To overcome these demanding factors and strike the right balance allowing for the production of higher grade steel that meets the current market price the installation of mechanical equipment as well as automation platforms and process technology must meet the latest technology standards. Being discussed in this paper are the different motives for modernizations along with their impact on project handling and commissioning philosophies. Experience gained during recent modernization projects in the field of flat steel rolling relating to Steckel / plate mills or current CSP® modernizations will be shared and demonstrate that each modernization has its own individual solution. Specific strategies are explained to help optimize production, increase plant agility and maximize the return on investment.

Aug 17, 2017

By Sandy Tavelli, Thomas L. Barkley

This discussion will present a case study in developing solutions to a metropolitan quarry’s public relations, legal, environmental, and productivity problems. It details an extensive and detailed project to address the blasting practice in a medium sized quarry that is surrounded by residential and industrial zones. The principle work was done over a four-month duration during the normal production season. It included detailed drilling and blasting audits for baseline information. In addition, geologic characterization, seismic modeling, correction of deviations from best practices, and implementation and monitoring of precise electronic timing to provide dramatic solutions for the quarry. The quarry is in the near suburbs of a large metropolitan city. It is framed on two sides by residential municipalities and on two sides by industrial zones. At the start of the project, the quarry was in court as a result of the lawsuit by one of the neighboring towns that was suing to close the quarry. The lawsuit had progressed to the advanced stage where in the Judge had appointed an arbitrator to make the decision of continued operation. This arbitrator was to observe our progress and recommend to the Judge the disposition of the case.

Jan 1, 2004

By Walter Ensinger

Working safely means working cost-effectively. Every "dangerous occurrence" and - even more so - every industrial accident causes disruptions in the planned course of construction. Besides moral and legal obligations, economic aspects are therefore also factors motivating increased efforts towards optimal prevention: improvements in work safety and protection of health are wise investments! Ever since its earliest days, the European Federation of Foundation Contractors (EFFC) has made this subject one of its key objectives and therefore set up a Safety + Environmental Working Group, in which experts from the member organisations exchange national experience and develop proposals for "best practices". The paper presents current developments and results from the work of the S+E WG with particular reference to the project "Ideas for Safety Improvement".

Jan 1, 2006

By G. Kazonich, S. L. McGill, J. W. Walkiewicz

Naturally occurring minerals and reagent-grade compounds were tested to determine their receptivity to microwave heating. The maximum temperature achieved for the samples and the time required to reach temperature are reported. A description of the microwave oven and a thermocouple technique that accurately measures and continuously records the temperature of samples during irradiation are reported. Extractive applications using the generated microwave data were investigated. Stress fracturing at mineral grain boundaries in a gangue matrix was shown. This should significantly affect grinding energy requirements and liberation properties. A method to produce a magnetic phase on pyrite surfaces, a method of using microwave heating to retort cinnabar concentrate, and a roast-leaching microwave treatment of chalcopyrite ore are described.

Jan 1, 1987

By Chris Twigge-Molecey

Demand for metals will continue to grow as global population numbers and prosperity levels steadily increase. Consequently, there will continue to be a need to design and construct new metallurgical plants. Business success in general requires projects to be financially successful and return appropriate value to their owners. However, in the metals industry, private and public sector financing sources have become very sensitive to the perceived inability of projects to contain costs and meet other business objectives. Thus, the capital for projects has become more difficult and expensive to obtain. It is instructive to note that Ernst and Young (2011) identified that: “Delivery of predictable project results bestows competitive advantage and market confidence to those corporations who successfully instill this discipline”. The implication for future projects is that they must be systematically developed to minimize perceived risks—and more importantly—to demonstrate that the risks are managed to achieve the business case. Then, provided that the project has been developed in a well-structured way, project success can again be defined as a project with: a final cost within 10% of the budget approved at the end of FEL3, when the project is properly defined and the permit conditions are agreed upon; a start-up date within three months of the definitive, scheduled startup date; production levels at 85% of design capacity within a year of starting commercial operation; production meeting the target environmental restrictions; and with zero lost time accidents during construction and startup. The plant design is one of many integrated activities required to achieve these objectives. This book represents a valuable link between the existing engineering literature that encompasses a wide range of engineering fundamental textbooks and design manuals and the project management literature such as the Project Management Body of Knowledge, or PMBOK® (Project Management Institute, 2014). It is evident throughout this book, that the design team is a small but essential part of a much larger project team comprising the project management, construction management, and construction contractor staff. Design activities must be regarded and managed as part of the integrated whole, with two fundamental links throughout the design process:

Jan 1, 2015

By R. Hurman Eric

Within the Ag-Pb-S ternary system, the boundaries of the immiscibility region together with the tie-line distributions were re-established at 925°C by the equilibrium-quenching technique where samples were kept in evacuated and sealed silica capsules. Activities of Pb were measured by the dew-point method along the Ag-Pb binary at 925°C, 1100° and l200°C, positive deviations were observed and the results were modeled by the Krupkowski formalism. Activities of Ag, Pb, and S, along the ternary miscibility gap were calculated at 925°C by utilizing the boundaries binary thermodynamics, phase equilibria and tie-lines. Activities of PbS within the pseudobinary Ag2S-PbS mattes were also measured by the dew-point technique and the results were again modeled by the Krupkowski formation where negative deviations were observed.

Jan 1, 2003

By Laurence G. Trudell

Geology and oil-yield data are presented for a 58-square-mile area encompassing the U.S. Department of the Interior oil-shale leasing program tracts in the western Washakie Basin, Sweetwater County, Wyo. Lithology and oil yields of samples from three Bureau of Mines coreholes are evaluated and correlated with Kinney Rim surface sections measured and sampled by the U.S. Geological Survey. Minable sections of oil shale averaging up to 25 gallons of oil per ton crop out on Kinney Rim in the Laney Member of the Green River Formation. Thick oil-shale sections in the Laney Member that average 15 gallons per ton represent 155 million barrels of oil in place per square mile. In the lower part of the Green River Formation the Tipton Shale Member contains a 20-to 40-foot section averaging 15 gallons per ton. Beds of high-volatile C bituminous coal up to 6 feet thick are present in intertongued parts of the lower Green River Formation and upper Wasatch Formation.

Jan 1, 1973

By N. V. Moraka

Mining companies are required by law to improve representation of women on their boards. However, progress in this regard has been slow. Boards of directors play an important role in formulating corporate strategy, risk assessment, and effective governance for sustained financial performance. Although some women have successfully maintained board seats, others have been unable to do so. It is difficult to ascertain whether women are being appointed as tokens to satisfy social pressures, as little is known about the experiences of women board members in mining, which may inform or refute tokenism. In-depth interviews were conducted with 20 women and 16 men across six listed mining companies. Thematic data analysis revealed evidence of tokenism where recruitment to mining boards is compliance-based and is informally driven by influential directors. Adverse boardroom experiences that further confirmed tokenism were reported by women, such as disregarding their contributions, condescending behaviour, and limited influence in decision-making, while other women sought to validate their competence and oppose social exclusion. This study recommends that a strong Board Chair and nominations committee is critical to ensure sustainable recruitment of competent and suitably qualified women; and further foster a culture of inclusivity and valuing gender-diverse boards.

Dec 13, 2023

By Matthew John M. Krane, Patrick E. Krane

This study examines the operations of the Cowper stoves attached to an iron blast furnace from a Second Law perspective. The exergetic efficiency of a 3-stove system operating at cyclic steady state is determined using a model accounting for the thermal, mechanical, and chemical flow exergies of the top gas and blast air, as well as the thermal exergy stored and released in the stoves. The analysis covers the heating and mixing of blast gas in one on-blast stove, and the combustion of top gas and its use to heat two on-gas stoves. The effect of different cycle times, and blast furnace operating conditions on the exergetic efficiency of the cycle is examined, and the optimal cycle time for different blast temperatures found. In addition, a study of the combustion parameters quantifies the advantages of using enriched oxygen in the combustors.

Mar 1, 2018

By S Brown

With oxygen conditioning routinely used in both the lead and zinc circuits at Pasminco Elura Mine a more sophisticated method of determining oxygen demand was required. It is known that different ore types have different oxygen consumption rates, however oxygen is added at a fixed rate regardless of ore type in the plant. Therefore, a simple laboratory test was devised to measure the oxygen demand of ores. The paper describes the technique employed, and provides an interpretation of the results. These data, together with pulp chemical measurements (Eh, pH and EDTA extraction data) were correlated against laboratory flotation performance to establish the relationship between oxygen demand and the position of the grade/recovery curve.

Jan 1, 2000

By E. C. Harder

BRITISH Guiana, Great Britain's only South American colony, may be reached by very comfortable steamers, both from North America and Europe. The trip from North American Atlantic ports requires about 12 to 14 days; that from Europe about 18 to 20 days. A number of steamship lines, including Canadian, American, and Dutch, have regular sailings between North America and British Guiana, with calls en route at various interesting ports in the West Indies and northern South America. Moreover, several lines, including British, German, and French, have steamships operating regularly between Europe and the West Indies. Indeed, so popular have the West Indian voyages become in recent years that, during the winter months, special cruises in considerable number are organized for many vessels that ply in the trans-Atlantic service in the summer. A trip to British Guiana, therefore, has become a delightful experience. After visits at the various attractive Leeward and Windward islands and Trinidad, the approach to the low, flat, British Guiana coast, with its muddy coastal waters extending for many miles offshore, is somewhat of a contrast. Arrival in Guiana waters is signalled by the appearance of the modern high-power Demerara Light, located "on a shoal about twelve miles from the mouth of Demerara river. From this point, if the tide is right, a pilot takes the steamer across the bar, eight to ten miles offshore, and into Georgetown harbour. At high tide, the water above the bar ranges from 15 to 18 feet in depth, depending on whether it is neap tide or spring tide; at low tide, the corresponding depths are 9 to 11 feet. As the bar is of soft mud, however, it is usually possible for vessels to pass over it with a draught of about two feet in excess of that indicated by the tide tables. Upon nearing the shore, one sees first the Georgetown wireless towers, then the light-house and the tall chimneys of sugar mills and of various factories in Georgetown, and finally the palms and other tropical trees and the houses of Georgetown itself along the sea shore and the east bank of Demerara river. Extensive wharves operated by various exporting and importing companies stretch along the river bank and activity prevails in Georgetown harbour. The principal exports are sugar, rice, gold, diamonds, bauxite, balata, lumber, fruit and other tropical products. The imports are food-stuffs, wearing apparel, and manufactured materials of many kinds.

Jan 1, 1936

By W. K. Tolley

This report presents data collected during research by the Bureau of Mines on corrosion of grinding media. Corrosion rates of eight alloys commonly used in grinding media were tested in synthetic mill water using an ultrasonic grinding device especially designed for this work. Electro-chemical measurements showed variations in corrosion rates for these alloys between 9.8 mpy for medium-carbon steels and 0.14 mpy for high chromium white irons. Bureau data are discussed along with data from the literature to indicate that corrosion causes less than 10 pct of the wear of grinding media in commercial grinding mills. A comparison of corrosion rates for various types of grinding media shows that alloying elements and electrochemically active inclusions in steel affect the corrosion behavior of the media.

Jan 1, 1984

By Frank P. Frandina, Diane R. Hirsch, David P. Field, Colin R. Weeks

To accommodate growth in air service and to follow the Master Plan for long-term airport development, the Metropolitan Washington Airports Authority established thed2 Development Program at Washington Dulles International Airport. A sub-surface Automated People Mover (APM) System is under construction to replace the Mobile Lounges as the primary people mover system at Dulles. To minimize disruption to airport operations the majority of the APM System’s crossings of Taxi lanes will be undertaken using Tunnel Boring Machines (TBM) or the New Austrian Tunneling Method (NATM). This paper explores the planning and design of these shallow tunnel segments for future generation aircraft loads, within the constraints of minimal construction access under post 9/11 security requirements and the context of the overall airport expansion program.

Jan 1, 2005

By N McKenzie, E Taylor, S V. L Barrett, H Lagger, A Purwodihardjo

This paper discusses the temporary support design methodology for the largest road caverns ever built in Australia—the Lutwyche Caverns—part of the Airport Link project in Brisbane, Australia. The Lutwyche Caverns with a maximum excavated span of 27 m form a key component of this major road project, allowing on and off ramps merging with the underground highway. In addition to the two large span caverns, a 15 m soft ground tunnel with 5 m cover above the caverns and two 24 m deep burial chambers for the 12.4 m tunnel boring machines (TBMs) had to be built in record time at Lutwyche.The temporary support design methodology involved the use of a range of analytical approaches, including empirical methods to provide a starting point for design development, key block models to determine the potential influence of discontinuities on excavation stability and 2/3D continuum and discontinuum models to determine the potential influence of adjacent excavations and the proposed construction staging on the design. In addition, probabilistic analysis of potential kinematic instability using a discrete fracture network (DFN) approach was also undertaken to establish the critical block loads for the temporary lining, while the continuum and discontinuum models were used to design the support for the 1.5 m diameter rock pillar at the north end of the northbound cavern.The numerical modelling was undertaken in close conjunction with the contractor to develop the optimal construction sequence, considering the available construction equipment on-site and the overall project program requirements. Part of the presentation will further show the applicability of the developed design during construction (deformations, monitoring field observations) and lessons learned for future cavern construction in Australia.CITATION:Lagger, H, Purwodihardjo, A, Barrett, S V L, McKenzie, N and Taylor, E, 2014. Temporary support design for the largest road caverns ever built in Australia – the Lutwyche Caverns, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 399–410 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Ground Improvement Committee

The evaluation of earthquake-induced liquefaction has become a routine part of geotechnical engineering design. For a given project, if an analysis identifies a potential for liquefaction and the consequences of liquefaction are deemed unacceptable, then some form of hazard mitigation is required. Mitigation efforts may consist of removing the liquefiable soils, bypassing the liquefiable soils with deep foundations, structurally accommodating the deformations or strength loss caused by liquefaction, or preventing the onset of liquefaction through ground improvement. The fundamental ground improvement mechanisms for liquefaction mitigation include densification, drainage, and reinforcement. When evaluating, recommending and specifying various ground improvement methods for liquefaction mitigation, practitioners should understand the fundamental mechanics involved and applicability and limitations of the various methods. The DFI Ground Improvement Committee offers a review of the fundamental mechanics and commentary on the applicability and limitations of each method to provide clarity and guidance on the issues related to ground improvement for liquefaction mitigation.

Aug 1, 2013

By W. E. Robinson

A laboratory study wan made to determine whether drying and preheating Colorado oil shale with waste retort gases has any appreciable effect on its oil yield. Samples of crushed oil shale were heated at subretorting temperatures in a specially constructed electric furnace by gases similar in composition to waste gases from oil-shale retorts. The results of this study showed that preheating oil shale with nitrogen or a reducing mixture had no effect upon the oil or water yield. However, oxygen in the preheating gas caused a decrease of oil and an increase of water. In general, the oil yield decreased with (1) increase in oxygen content of the heating gases, (2) increase in temperature of the heating gas, (3) increase in heating time, and (4) decrease in the particle size of tho shale. The decrease in oil and the increase in water resulting from preheating were due to oxidation of the benzene-insoluble organic material (kerogen) rather than to oxidation of the benzene-soluble organic material (natural bitumen) in the shale, A small amount of oil was volatilized during preheating, which would constitute an additional loss if prober precautions were not taken to recover it. The results obtained in this laboratory study indicate that oil shale can be preheated without appreciable decrease in oil yield by proper selection of preheating conditions.

Jan 1, 1951

By W. C. Morgan

The Federal Surface Mining Law enacted in 1978 is now being translated into regulations which must be followed in future coal mining. Substantial change to mining procedures is required to maintain stricter air and water control while mining and to return the mined out land to equal or better use than before. These changes do not come easy; and in most cases, they create a substantial additional cost. Based on field observations and mining studies, Caterpillar has been making suggestions on the use of their types of equipment to conform to the new standards at the least cost. This paper will be a brief review of some of the overburden stripping and reclamation methods suggested by Caterpillar. A production and cost comparison of dragline, scraper/dozer and truck, loader systems in 20 to 150 ft. Overburden conditions illustrates potential cost savings using mobile equipment.

Jan 1, 1980