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By Gerd Weyand

Gontermann-Peipers GmbH (GP) Germany developed a new, high alloyed steel grade for the manufacturing of back-up rolls. The advanced GP double pour casting processes provide highest flexibility in being quite open in rolls work layer chemistry and hence microstructure with no influence on core respectively neck properties. GP took the process advantage to provide a brand new back-up roll grade with remarkably reduced roll wear while operating with textured work rolls. In the meantime several successful trials have been made with this new roll grade on different Skin Pass Mills. As a result the performance of back-up roll and thus availability of mill will be improved while specific costs for mill will drop. This quite new back-up roll grade has recently been launched. As next step increasing the field of applications is under progress.

Aug 17, 2017

By Joseph M. Kuchta

This Bureau of Mines manual is oriented to the technical needs of an investigation of fire or explosion accidents and includes various practical and theoretical information that is needed in analyzing accidents or evaluating conditions that might lead to an accident. It is applicable to accidents in the chemical, mining, transportation, and other fuel-related industries. Specific procedures for conducting an accident investigation are outlined, and various guidelines are given for developing the fire or explosion evidence. Ignitability, flammability, and physicochemical data are presented for over 500 combustible gases, liquids, and solids; empirical and theoretical expressions are also given for extrapolating the behavior of combustible-oxidant-diluent systems to various environmental conditions. In addition, various data pertinent to damage analysis are summarized to facilitate the task of the investigator in developing plausible accident scenarios.

Jan 1, 1985

By Jaime Herrero, Santiago Gómez, Pablo Segarra, José Ángel Sanchidrián

This paper presents a mathematical model for the study of the 2D movement of blast bench faces based on the high-speed video analysis of three blasts at El Aljibe quarry (Spain) recorded at 2,000 frames per second. In these blasts, a set of bags of 0.75 × 0.75 m were placed in front of a selected blasthole defining a reference plane in which to study the kinematics of the movement. The burdens range from 3.86 m to 5.54 m, with a bench height of 12–13 m. An affine transformation system was calculated to convert coordinates from the video images into actual spatial coordinates. The problem is established from a multi-objective minimization approach in order to simultaneously optimize two defined objectives: trajectory fitting using Total Least Squares regression, and time–displacement regression using Ordinary Least Squares. Muti-objective minimization formulation produces Pareto plots of non-dominated solutions, i.e., optimal combinations of initial velocities and response times, (i.e. time between detonation and the onset of bench face motion). From the Pareto frontier, the most balanced solution is selected. Blast response time lasts only a few milliseconds and appears so brief at the frame rate used that it is difficult to detect visually. In this context, the bi-objective optimization-based approach proves to be a more robust tool than frame-by frame survey for quantifying such a rapid event while also maintaining a strong performance in the trajectory fitting task. Root Mean Square Error (RMSE) for the two minimizations average 0.22 m and 0.13 m, respectively. The initial velocities obtained range from 4 to 17 m/s, and the response times 0.7 ms to 21.7 ms. An analytical model is also presented for predicting fragments initial velocity and response time as functions of blast geometry and rock mass properties, explaining approximately 87% of the total variability.

Jan 26, 2026

BIBLIOGRAPHY Allen, C.A, Analyses of Utah Coals, United States Bureau of Mines Technical Paper 345, 1925, pp. 90. Allen, J.E. and E.M. Baldwin, Geology and Coal Resources of the Coos Bay Quadrangle, Oregon, Oregon Department of Geology and Mineral Industries Bulletin 27, 1944, pp. 160. "Aluminum Boom Raises Productivity", Coal Age, Vol. 82, No.6, June, 1977, pp. 103.

Jan 1, 1978

By A. A. Compoli

Injecting water under pressure to wet the coalbed in advance of mining reduces mining-generated respirable dust. Owing to economic and geological barriers, water infusion for longwall dust control in the United States is currently limited to the Pocahontas No.3 Coalbed in Virginia. Water is pumped into the coalbed through underground boreholes drilled horizontally from the headgate toward the tailgate side of retreat longwall panels. This paper theorizes that the barriers to widespread utilization of water infusion for longwall dust control could be overcome by long-duration, low-pressure water infusion through vertical gob gas boreholes. Currently, 43% of the 72longwall mines in the United States employ vertical gob gas boreholes. Computer coalbed reservoir simulation suggests that one vertical surface borehole could infuse the same longwall panel area as four horizontal boreholes in the current water infusion system for longwall dust control in the Pocahontas No.3 Coalbed.

Jan 1, 1995

By George Weaton

Two years ago the general features of the St. Joseph Lead Company's zinc-smelting process were described.1 At that time the discussion was limited to a description of the production of high-purity electrothermic zinc oxide. The present paper will describe the commercial production of electrothermic zinc metal. Since a fairly complete description of the plant of the Josephtown smelter was given in the earlier paper, the brief recapitulation given here will be limited to mention of additional equip-ment recently installed and a bare outline of the preparatory process. The raw material is zinc sulphide concentrate received from the com-pany's mines in St. Lawrence County, New York. An average dry-weight analysis of this material is: Zn, 58.28 per cent; Pb, 0.56; insoluble, 1.6; Si02, 1.12; Fe, 6.4; CaO, 0.47; MgO, 0.27; S, 31.9; Cd, 0.1; Cu, 0.06; Mn, 0.24. Moisture content is usually about 3 per cent. Three 21-ft. 6-in. diameter, 12-hearth Nichols-Herreshoff furnaces roast the concen-trate to a calcine of average composition (first 10 months of 1938) : Zn, 67.69 per cent; Pb, 0.06; insoluble, 1.75; Si02, 1.26; Fe, 7.24; CaO, 0.47; MgO, 0.36; S, 1.88; Cd, 0.1; Cu, 0.07; Mn, 0.27. The sulphur dioxide gas, after passing through a waste-heat boiler, proceeds through a recently redesigned low-resistance gas-purification assembly to the contact sul-phuric acid plant, of which the capacity is 200 tons of concentrates per day. The calcine is mixed with a portion of returned furnace residues and sintered on 42-in. by 44-ft. Dwight-Lloyd sintering machines, gas-fired. Wind-box gases pass through air coolers before filtering in a 1440-bag Dracco unit, and thence to stack. The Dracco fume is mixed with Cottrell dust, from roaster gas cleaning, and sent to the leach plant, where it is roasted (SO2 to acid plant) and leached with sulphuric acid to recover, as end products, lead sulphate, zinc sulphate and cadmium.

Jan 1, 1939

By Marcos Valdéz Córdova

El presente estudio señala el proceso de mineralización en el domo de Yauli a través de una revisión en el comportamiento de dominios estratigráficos, estructurales, intrusivos, metamórficos y distintos minerales de alteración hidrotermal. Asimismo se describe la geología, su estructura, la alteración de los intrusivos, la alteración de los silicatos metamórficos, la alteración de los mármoles y calizas dolimíticas, cuerpos, mantos y las vetas de reemplazamiento.

Nov 20, 1978

"Geometallurgy is a discipline that seeks to improve the sustainability of the extraction of metals and minerals by promoting the smarter use of non-renewable resources, better energy efficiency and greater use of renewable energy. To achieve these goals, development of innovative technologies and approaches are being developed along the entire commodity value chain, starting with exploration and extraction and extending to reuse and recycling. This paper discusses the geometallurgy of industrial minerals with special emphasis on kaolin, a versatile industrial mineral applied in ceramics, paper, paint, plastics, rubber, pharmaceuticals, cosmetics, ink, sealants, adhesives, sanitary ware, glass fibre, toothpaste, animal feed etc. Aspects of kaolin extraction in south-west UK are analysed from a geometallurgical perspective. While geometallurgy already features in kaolin extraction, its role can be significantly expanded by combining advanced in-pit characterisation and orebody modelling with integrated planning and control of the refining and calcination process. This paper highlights the importance of innovation in realising the full potential of geometallurgy.CITATION:Glass, H J, 2016. Geometallurgy – Driving Innovation in the Mining Value Chain, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 21–28 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By C. R. Stephan

The Mine Safety and Health Administration's (MSHA) Ventilation Division continues to evaluate proposed explosion-resistant seal designs. There are currently eleven specific designs for explosion-resistant seals that are suitable for construction in underground coal mines. Seal construction in operating mines must be equivalent to those constructed in the Experimental Mine during the explosion testing program. Accidental failures of seals have occurred due to explosion pressures below 138 Kpa (20 psi). The possibility exists that the failed seals were not properly constructed. Also, conditions in the vicinity of the seals may change. Water may accumulate against the seals, heave or sag may cause detrimental effects on the seals, and sloughage of the ribs may negate hitching. If seals are not properly installed or maintained, they could fail when subjected to explosion pressures. If seals fail for any reason, the possibility exists for explosion propagation throughout large areas of the mine. There could be catastrophic consequences to an event of this nature. This report will present a limited discussion on the construction of each of these seals and will address related issues.

Jan 1, 2001

By Charles T. Holland

ANALYSIS of 117 occurrences of bumps in coal mines shows that 67.6 percent are associated with pillar-line points.4 Slabbing and splitting pillars, development, and other unfavorable milling practices in abutment areas may be a contributory or the primary cause of bumps. The cure for pillar-line bumps is to recognize areas that can be expected to become highly stressed and to project the mining plan and operations to eliminate such areas insofar as possible. If such areas cannot be eliminated, then the mining plan and operations should be projected to avoid the necessity of disturbing these areas before the stresses have been dissipated.

Jan 1, 1954

By W. W. Adams

Lower accident rates were the outstanding feature. of the second annual sand and gravel safety competition conducted in 1930 by the United States Bureau of Mines in cooperation with the National Sand and' Gravel Association. Both the frequency and, severity rates for accidents were greatly reduced as compared with those shown by the first year's contest, that for 1929. Three times as many plants were enrolled, and the number of man-hours of work represented was more than doubled. Seventy-six sand-and-gravel plants, situated in 20 States, participated in the Competition, as compared with 26 plants, located in 13 States, in the year before. The number of man-hours of employment, which indicated the amount of exposure to occupational hazards, was 4,915,592, an increase of more than 100 per cent over the previous year's total of 2,259,572 hours. The frequency of accidents declined from 74.4 per million hours for all plants enrolled in the first year's contest to 42.7 per million man-hours for all plants enrolled in 1930. The accident-severity rate was reduced from 9.7 days of disability per thousand man-hours of exposure in 1929 to 5.9 days of disability per thousand man-hours of exposure in 1930. The actual number of accidents reported for 1930 by 76 plants included four deaths and 206 injuries whereas the 26 plants that were enrolled in 1929 reported three fatalities and 165 injuries. Under the rules of the contest all "lost-time" injuries are reported--that is, all injuries that disable an employee for more than the remainder of the day on which the accident occurred. If the employee is physically able to resume his work on the day following the accident, the injury is not classed as a lost-time injury. The contest covered accidents and man-hours worked by all employees at the plant who were employed by the same company, and included work up to the point of delivery of the material directly to consumer or to independent agency of transportation--in other words, to point of relinquishment of control of the material by the producer.

Jan 1, 1931

By M S. Tuohy

Since the independent review of fatal accidents in the mining industry carried out by Dr Sean Brady (the ‘Brady Review’), High Reliability Organisations (HROs) and their operating principles have been discussed across the Queensland mining sector. HROs are organisations said to consistently avoid serious failures, reliably delivering their organisational objectives despite operating in environments characterised by high levels of inherent risk and/or operational complexity. HRO concepts have previously found application in other similarly hazardous industries to mining. However, as Hopkins (2009) pointed out, HROs ‘are very elusive creatures that inhabit the realm of theory more than the real world’. The Queensland Resources Council (QRC) with support from the Commissioner for Resources Safety and Health initiated a review of how HRO principles can be translated to the mining industry. The review was conducted by Noetic, an Australian management consulting company that specialises in hazardous industries, including mining and metals, and has prior experience applying HRO theory.

May 5, 2022

By Rowena Anderson

Mining companies are now looking for more effective ways to engage the community in public participation. Consensus-based approaches are becoming the most popularly applied way of achieving meaningful public participation. This paper introduces the principles surrounding consensus-building approaches and the processes for getting them started. The Healthy Communities Movement is one such consensus-based approach that offers a well-established holistic model for conceptualizing a healthy sustainable community. It also highlights the importance of public participation as an essential component of achieving a sustainable community. The paper concludes by illustrating how current company-community relations programs can utilize these models.

May 1, 2002

By Forrest T. Moyer

Quarry accidents in 1963 caused 61 fatal and 3,468 nonfatal injuries which occurred at respective frequency rates of 0.31 and 17.91 per million man-hours of worktime. The fatality record in 1963 was better than in 1962 but was appreciably worse than in 1.961. For nonfatal injuries, the 1963 record was slightly worse than in 1962 but was better than in 1961. The injury--severity rate of 2,913 days lost or charged per million man-hours in 1963 was better than that of 3,046 in 1962, the first year for which such data became available. The average severity of all injuries in 1963 was 160 days lost or charged per injury, 15 less than in 1962. An average of 91,960 men were at work on active days in 1963 and these men had an aggregate worktime of 193.7 million man-hours during the year.

Jan 1, 1972

By Syd S. Peng

Coal mine ground control is the science of the application of rock mechanics principles to coal mining operations. More acceptance of ground control techniques by the US coal mining industry has been seen in the 1980s. It has been demonstrated many times that a proper ground control design is key to a successful coal mining operation. However, numerous in-mine applications of various ground control techniques by the author indicate that cur¬rent techniques need improvement. The biggest problem in coal mine ground control is that miners are dealing with materials of rapidly varying properties and occurrence. And only the exposed surface can be identified positively. Thus, in attempting to solve the ground control problems, many unknown factors are assumed. Some of these problems deriving from such assumptions are discussed here. Coal pillars There are two types of coal pillars - barrier and chain pillars - depending on the purpose. Barrier pillars are those located between panels or sections or mines. Their objective is to isolate the mined-out effects of one from the other. Chain pillars are characteristic of room-and-pillar mining. They are designed to support the overburden load and protect the surrounding entries and crosscuts. Pillar design is the most popular and, frequently, the only ground control technique employed by coal operators for mine design. There are many pillar design formulae available (Bieniawski, 1983; Peng, 1986). Nearly all consider both size and width/height effects. Specifically, pillar strength decreases with increases in pillar size and increases with increase in the ratio of width to height. However, the manner of those changes varies with investigators. Consequently, the pillar size determined varies considerably from investigator to investigator. And the variation grows much more pronounced as the seam depth increases (Fig. 1). The question, then, is which one should be used? One may say each formula is developed for a particular coalfield. A particular formula may have been used to design a pillar, which has not failed. Does that mean it was over designed? Not necessarily, because no one can confirm its stated "safety factor." Recent case studies (Peng, 1986; Tang and Peng, 1988) show that all pillar formulae are too conservative for chain pillar design in room-and-pillar mines due to the following two problems: • Uncertainty about in situ pillar strength. All formulae employ uniaxial compressive strength of selected samples tested in the laboratory and scaled to that for underground pillars. The scaling factors are not well proven. In situ testings by Bieniawski (1969) suggested that 1.5 m (5 ft) pillars are representative of in situ pillars that, after being tested in various US coal mines, are not universally applicable. • Uncertainty about the actual loading on the pillar. The most frequently used tributary loading theory defines the loading as total overburden weight tributary to each pillar (from roofline to surface). This is too conservative when it applies to coal measure rocks. The overburden consists of layered strata of different stiffness. Many stiffer strata will self-support over small roof spans. Depending on the location of these strata above the coal seam, it will reduce pillar loading in various proportions. It follows that total structural analysis using, for instance, finite element method is more appropriate. It can take into account the interaction of roof and floor strata with coal. This has been demonstrated by Peng et al. (1986,1988) on several case studies. However, the validity of the finite element structural analysis depends on the accuracy of in

Jan 1, 1989

By A. Golabchi

Building Information Modeling (BIM) is an increasingly popular method for generating and managing facility information during the life cycle of a building, ranging from facility conceptualization, through design, construction and its operational life. Organizations involved in Facility Management (FM) have the opportunity to use BIM as a knowledge repository to document evolving facility information and to support decisions made by the facility managers during the operational life of a facility. This paper demonstrates the potential of using BIM to develop algorithms that automate decision making for FM applications. The potential of utilizing BIM as an analysis tool is demonstrated through the scenario of HVAC (Heating, Ventilation, and Air Conditioning) system failure in an operating facility. In case of a typical HVAC malfunction today, facility occupants record complaints in a ticketing database maintained by the FM organization. Upon receiving notification of HVAC system failure, facility inspectors visit the location to confirm the reported failure. Upon confirmation, facility managers review building plans and specifications to develop a detailed plan of action to repair any HVAC components suspected of damage. Based on the plan of action, inspectors visit the facility to inspect and, in case of damage, repair the appropriate HVAC system components. These FM practices ? as currently implemented across the industry ? are labor intensive, time consuming, and often rely on unreliable and outdated information. To address these shortcomings, the authors propose an alternative methodology of HVAC fault detection in operational buildings. The authors implement an algorithm that leverages complaint ticket data and automates BIM to determine potentially damaged HVAC system components. Based on the list of HVAC components suspected of damage, the algorithm develops a plan of action for the facility inspectors. Finally, the authors discuss the advantages of the proposed method as well as the challenges of implementing automated BIM-enabled decision making processes in the FM industry.

Aug 1, 2013

By Francisco Alberto Marreiros da Rocha Filho

No processo de laminação a quente ocorre ocasionalmente a perda de ductilidade a quente que pode causar o fenômeno denominado como “abertura de cabeça” da barra durante a sequência de passes. Essa perda de ductilidade a quente pode ser severa e causar interrupções no processo produtivo. Esse fenômeno pode estar associado a diversos fatores entre eles: composição química do aço; defeitos presentes no tarugo; condições do processo de laminação; e temperatura do aço durante o processo, principalmente nos passes de desbaste e intermediários de laminação. No processo em estudo, a perda de ductilidade a quente ocorre associada à laminação de vergalhões a partir de tarugos oriundos diretamente do lingotamento contínuo. O presente trabalho tem como objetivo avaliar a influência da temperatura e da microestrutura formada ao longo do processo na perda de ductilidade a quente das barras através de um exame comparativo entre os vergalhões laminados com e sem o uso da etapa de reaquecimento.

Oct 30, 2017

By G Le Juge, K Waldock

The current suite of bulk mining explosives has been available to the industry for over 20 years. The flexibility and performance of ammonium nitrate based emulsion blend explosives were accepted by the mining industry in the early 1980s. These water resistant explosives rapidly displaced the water gels and slurries developed during the previous two decades. However, since the 1980s there has been no equivalent step change to the basic formulation or application of bulk explosives, although there has been a continuous process of refinement with respect to stability, handling characteristics and most significantly, cost. In the 1980s explosives supply contracts were awarded based on technical evaluations, usually accompanied by field trials. Technical personnel from both mining companies and explosives suppliers dominated the negotiations and there was a strong focus on explosive energy and blasting requirements. Today, explosives from alternative suppliers are difficult to differentiate on the basis of energy so the focus has shifted to aspects of service and price û bulk mining explosives are now largely treated as a commodity and the negotiations are dominated by commercial personnel. Commercial pressures from large mining companies have seen a substantial reduction in the real price of explosives. However, this has come at a cost. In order to reduce manufacturing costs, emulsion formulations have changed. In general they are not only cheaper, but also less energetic. Powder factors have had to increase to achieve the same blasting results, especially in hard ground. It is debatable whether the mining companies have achieved all of the economies they were seeking. This paper discusses these issues and argues that the mining industry would benefit from taking a more technically driven approach to meeting their blasting requirements. Recent trends towards more open contracts between the mining companies and their suppliers can be extended to explosives. To achieve this, mining companies will need to acquire sufficient technical knowledge to take a more pro-active approach to specify the characteristics of the explosives required to maximise the economic performance of their operations.

Jan 1, 2004

By S. Okubo, K. Fukui

Empirical equations established for estimating the rock strength of the working face based on the cutting forces of a tunnel boring machines (TBM) are further examined and discussed with respect to the dominant factors affecting TBM performance. Constants in the equations are related to TBM-specific parameters such as excavation (tunnel) diameter, cutter diameter, and cutter distance. The relationship between the constants and the TBM specifications is examined in this study on the basis of data collected at ten tunnels, and it is found that the constants are most strongly influenced by the cutter diameter and tunnel diameter. Zur Schätzung der Gesteinsfestigkeit an der Arbeitsfläche ermittelte empirische Gleichungen, die auf den Schneidekräften von Tunnelbohrmaschinen (TBM) beruhen, wurden weiter im Hinblick auf die vorherrschenden, die Leistung der TBM beeinflussenden Faktoren hin untersucht und diskutiert. In der Gleichung enthaltene Konstanten werden zu den TBM-spezifischen Parametern wie Auschachtungs- (Tunnel) Durchmesser, Schneidendurchmesser und Schachtlänge in Beziehung gesetzt. Die Beziehung zwischen diesen Konstanten und den technischen Daten der TBM wird in dieser Studie auf der Basis der bei 10 Tunnelbauten gesammelten Daten untersucht. Dabei wurde gefunden, dass diese Konstanten am stärksten von den Durchmessern der Schneiden und der Tunnel beeinflusst werden. Cette étude examine et discute les équations empiriques permettant d'estimer la résistance de la roche attaquée aux forces de coupe des tunneliers dans le cadre de l'étude des facteurs dominants affectant les performances des tunneliers. Les constantes de ces équations concernent les paramètres spécifiques des tunneliers comme le diamètre d'excavation (du tunnel), le diamètre du couteau et la distance de coupe. Cette étude examine le rapport entre ces constantes et les caractéristiques techniques des tunneliers d'après des données collectées dans dix tunnels et elle conclut que ces constantes sont principalement influencées par le diamètre du couteau et le diamètre du tunnel.

Jan 1, 2003

By Frank G. Schwartz

VARIABLES OF composition and environment affecting storage stability of gasoline-type fuels were studied, utilizing radioactive tracers and other analytical techniques. Changes in gasoline composition brought about by aging were determined and correlated with gum formation. The amounts of reaction of selected gasoline components, measured by radioactive tracers, were determined in a gasoline-type blend and in a mixture of 17 selected pure gasoline components. The data show that sulfur compounds, nitrogen compounds, polycyclics, and olefins enter into gum-forming reactions. Certain sulfur and nitrogen compounds were found to be most reactive in the gum-forming process. Results of this study indicate that the aromatic constituents of gasolines may contribute substantially and directly to gum formation. A mixture of tetralin and indan-type compounds is reactive, and this mixture appears to be the main aromatic portion entering into gum formation. A secondary but significant amount of naphthalenes also appears to have reacted in the gum-forming process. Analyses of the sulfm compounds in a fresh and an aged fuel indicated that elemental sulfur, hydrogen sulfide, thiols, sulfides, and disulfides were depleted during aging, but thiophenes and residual sulfur compounds were not depleted by fuel deterioration.

Jan 1, 1964