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By Reynold Q. Shotts

A study was made of the coal resources of an area in Jackson County, Ala., forming a part of the Flat Rock, Henegar, and Stevenson quadrangles. The area studied is a portion of the Plateau coalfield on Sand Mountain and is near the Tennessee Valley Authority's Widows Creek steamplant. Since no detailed geological study of this area had been published, some reconnaissance work was done. The coalbeds and adjacent strata such as sandstones, conglomeratic sandstones, and conglomerates were studied. Available drill logs, together with the areal geology, provided sufficient information to permit correlation of the coalbeds and an estimation of coal reserves. For all categories of reserves, computed on a regional basis, a total of 72,920,000 tons of coal more than 14 inches thick is estimated for the areas studied in Stevenson, Flat Rock, and Henegar quadrangles. Of this tonnage, 40,001,000 tons is estimated to have less than 60 feet of overburden. The total measured coal reserves for the above three quadrangles are 16,359,000 tons, with 12,411,000 tons under less than 60 feet of cover.

Jan 1, 1966

By Garforth W.

The chairman announced the new government duties of the out-going President, Sir Thomas Holland, and the formation of a new standing committee on mining to advise the Advisory Council for Scientific and Industrial Research on suitable projects for grants. Some of the potential lines for investigation into the best methods of winning and presenting coal in the best commercial condition include wasteful practices in operating steam boilers, national loss due to neglecting recovery of coal by-products, and the leaving of large areas of coal for fear of spontaneous combustion or as boundary pillars and support

Dec 1, 1916

By J. E. Chilton

Underground miners may be exposed to hazardous quantities of toxic gases, such as carbon monoxide (CO), generated from mine fires or explosions. Every underground miner is required to carry a filter self-rescuer (FSR), which when operated will remove CO from the miner's breathing air. In addition, every underground miner must have a self-contained self-rescuer (SCSR) near the worksite that will supply breathing oxygen. In many situations, miners do not know when to don either rescuer since they do not know if there is a fire in the mine, nor do they carry instrumentation necessary for the detection of the toxic, colorless, and odorless fire product CO. If each miner carried a personal CO alarm, which would respond to high concentrations of CO, the miner would then be alerted when to don either the FSR or SCSR and exit the mine. A prototype personal miner's CO alarm called PEMCOAL was developed by the U.S. Bureau of Mines. The PEMCOAL unit is small enough to be carried on a miner's belt, has a flash lamp visual alarm, requires no calibration for use, and uses a chemical sensor that changes color by reaction with trace quantities of CO. The chemical sensor was tested at concentrations of CO from 10 to 1,000 ppm, at temperatures from 5° to 40° C, and with several potential mine gas interferents. The PEMCOAL alarm times were sufficiently fast to warn miners before they are exposed to hazardous quantities of CO.

Jan 1, 1989

By A. E. Lewis

The emphasis of this paper is on the characterization and testing of the slag produced by a secondary lead refinery. This work forms part of a broader investigation aimed at reducing loss of valuable product from the process as well as minimizing the environmental impact of the process wastes. It was this work that led to a critical examination of the standard waste classification tests. Characterization of the slag was carried out using a number of complementary techniques. In the broader context, the slag characterization aided in identifying process deficiencies and thus was a critical tool in suggesting potential for process optimization. For this study, the slag characterization provided a relatively comprehensive picture of the composition and properties of the slag, which facilitated understanding the behaviour of the slag under batch test conditions. On the basis of quantity of hazardous components alone, the slag is hazardous according to South African Acceptable Risk Limits (ARL). However, when both the quantity and the leach potential of the hazardous components is taken into account, standard waste tests carried out by three independent agencies indicate that the slag should not be classified as hazardous according to local regulations. Also, according to United States Environmental Protection Agency (US EPA) limits, which are independent of the quantity of the waste, the slag would not be classified as hazardous. The standard waste tests used by the independent agencies was the Toxicity Characteristic Leach Procedure (TCLP), a test which was developed by the US EPA to classify hazardous wastes. One of the requirements of this batch test is that it should be quick, simple to carry out and that the results should be reproducible. Previously, the applicability of the TCLP test to mineral processing and metallurgical wastes has been challenged on a number of points. Additional testing of the slag was carried out using both the TCLP and the Synthetic Precipitation Leach Procedure (SPLP) recommended by the American National Mining Association as being more appropriate for mineral processing wastes. The particular physical and chemical characteristics of the secondary lead slag highlighted additional limitations of both the TCLP and SPLP tests as standard laboratory batch procedures. Keywords: environmental protection, secondary lead processing, slag, leach testing, TCLP, SPLP, ARL, hazardous waste, batch tests

Jan 1, 2000

By Cristian Deiner Dutra

O desgaste dos metais afetam diretamente os componentes de um eixo de transmissão cardan. Este estudo analisou o desgaste apresentado pelo eixo cardan em contato com a luva interna e externa, até o momento da fratura. A análise da região fraturada se deu por imagens metalográfica geradas pelo Microscópio Eletrônico de Varredura (MEV); e a análise química pelo sistema Espectrometria de Energia Dispersiva de Raios-X (EDS), contida também no MEV. Observou-se pela micrografia, uma fratura caracterizada pelo desgaste, agravada pelo esforço em fadiga. A análise química detectou ausência de importantes elementos químicos em aços com aplicações em desgaste.

Oct 30, 2017

By Martin Pratt

This paper is an overview of deep foundation engineering in Hong Kong past, present and future. The enormity of the subject compared with the space available makes brevity inevitable. Issues of construction and design are covered and some examples of recent challenging projects are given. The content is aimed at those with an interest in foundations generally, but with limited knowledge of the Hong Kong scene. Reference is made to informative publications for further reading on specific topics.

Jan 1, 2000

The Greymouth Coal Project is a proposal to mine by the application of proven hydraulic, and room and pillar underground mining methods; and to process the equivalent of an average of 1.7 million tonnes per year over a forty-year period. The proposed mine site is located ten kilometres north of Greymouth, on the west coast of the South Island of New Zealand. Of the three separate mineable seam groups, the thick Main Seam Group, which makes up 77% of the total resource, will be mined by hydraulic mining technology.   It is proposed to market and produce a high volatile bituminous type coal with low ash (6%) and sulphur (0.4%). Because the inherent ash content is low, the requirement for coal treatment will only be the use of a single cell jig circuit to control the effects of rock dilution and partings. The resulting coal product is tentatively planned to be transported by rail to the port at Lyttelton for loading on to Panamax or Post Panamax size vessels.

Jan 1, 1997

By Robert B. Parsons

"The Canadian mining industry is not off to a good start in the 1993/94 budget season. Of the five provinces and territories to table budgets as of March 31, 1993, the industry's scorecard shows: one win, one tie, and three losses.IntroductionBy the end of March, five of Canada's twelve provincial and territorial governments had tabled their 1993/94 budgets. The mining industry is off to a bad start. The industry's scorecard shows one win, one tie, and three losses. Only Newfoundland appears to be paying any attention to the industry's concerns about the impact of taxation on competitiveness. It is particularly disconcerting to see that non-profit based taxes continue to increase, at a time when these taxes are the focus of a united attack by the entire industry.NewfoundlandFirst, the good news. On March 18, 1993, Finance Minister Winston Baker announced the following changes to the province's mining tax regime:"

Jan 1, 1993

By E. R. Spencer, E. R. Bauer

Previous studies and research efforts have shown that noise-induced hearing loss (NIHL) is a problem in the U.S. mining industry. In response, researchers at the National Institute for Occupational Safety and Health (NIOSH) have been conducting a cross-sectional survey of equip­ment noise and worker noise exposures in the mining industry to estimate the potential for NIHL within the mining community. One commodity recently surveyed was the extraction of sand and gravel from surface pits and by dredging. To address the potential for NIHL in the sand and gravel industry, sound levels on and around the dredges and processing equipment were recorded to iden­tify areas of high noise levels. Full-shift worker dosimetry, in conjunction with task observations, was documented to determine the relationship between exposure and source. This paper presents research examining noise on dredges used in several surface mine sand and gravel operations and in the processing facilities. Results indicate that there are areas on the dredges (crane, suction pumps and diesel engines) where sound levels greater than 90 dB(A) are pres­ent. In addition, crushers and screens used in the processing of the sand and gravel also generate sound levels greater than 90 dB(A). Although no surveyed worker exceeded the Mine Safety and Health Administration’s (MSHA’s) permissible exposure level (PEL) of 90 dB(A) eight-hour time-weighted average (TWA8), laborers, mechanics, oilers, helpers, pickers and greasers are the workers most likely to be exposed to hazardous sound levels and to thus develop NIHL over time

By D. Michael Holloway

The California Department of Transportation (CALTRANS) evaluated several pile foundation schemes for supporting the structures along the realignment of Interstate 880. The project replaces the double-decked (Cypress) viaduct collapsed in Oakland, California during the 1989 Loma Prieta Earthquake. Structural support demands led to the selection of steel pipe piles (16-, 24-, and 42-inch-(406-, 610- and 1067-mm-)diameter), filled with concrete and steel reinforcement. Deep penetrations required through layers of very dense/cemented sands in some locations, caused serious drivability and pile integrity concerns. The need for large pile driving hammers and large diameter steel pipe piles pushed the engineers well beyond local experience. Such questions as the feasibility of driving the pipes closed-ended through dense upper strata and quantifying the effects of installation on the long-term capacities of the piles led Caltrans to develop a comprehensive pile test program to address the design and construction issues effectively. The results were furnished to prospective bidders on the production stages of the ensuing contracts.

Jan 1, 1995

By G. Forté, R. Girard

The Alcan Bayer Process Experimental Centre (BEC) is an essential development tool for the Bauxite & Alumina researchers at the Alcan Arvida Research and Development Centre in Jonquiere, Quebec. Between the laboratory tests and the industrial prototypes or the industrial applications, the BEC is a key element for technology transfers. The Bayer process is the extraction of aluminium oxide (or alumina) from the bauxite ore. The Bayer Experimental Centre's history and flowsheet are presented. The major pieces of equipment are described. Safety and design considerations are presented. Finally, examples of applications, double digestion and pressure decantation, are briefly described.

Jan 1, 2004

By Aldo Henrique de Almeida Barbosa

Dentre os revestimentos galvanizados a quente, o galvannealed (GA) destaca-se por possuir uma estrutura composta por fases Fe-Zn, o que lhe confere excelente desempenho na aplicação em peças de alta solicitação. A qualidade do revestimento GA é governada principalmente pelo tratamento de galvanneling, tendo em vista seu efeito na formação dos compostos Fe-Zn. A influência desse tratamento é ainda mais pronunciada em aços com características de bake hardenability (BH), pela presença de elementos que alteram a sua reatividade. Nesse estudo, foram avaliados os efeitos das condições de galvannealing na formação do revestimento GA sobre aços BH. Para tal, ciclos de galvannealing variando-se a temperatura de aquecimento entre 530°C e 580°C foram simulados em escala de laboratório. Além dos ciclos completos, foram também realizadas interrupções do tratamento ao longo da etapa de encharque, através de resfriamentos bruscos das amostras, com o objetivo de avaliar a microestrutura do revestimento ao longo de todo o tratamento. Os resultados permitiram determinar os mecanismos de formação e crescimento dos compostos intermetálicos Fe-Zn que constituem o revestimento galvannealed, e correlacioná-los com as características do produto final, de maneira a estabelecer faixas adequadas de processamento desse material.

Jul 30, 2018

This paper discusses the impacts that advances in metallurgy and process engineering have on minerals project execution. Ausenco's business is focused on integrating minerals processing technology and the delivery of cost effective processing plants that exceed client performance expectations. The metallurgical development is a small but critical part of this process. Metallurgical development and innovation outcomes need to be transformed into an engineered solution and that solution converted into an operating plant in a cost conscious and competitive environment. Including new or innovative processes in a project flow sheet increases a project's technical and commercial risk. However, it also gives the project, and/or the engineering company, a potential advantage over projects using mainline practices. Managing the balance between risk and opportunity has been a cornerstone of Ausenco's success in recent years. Some advances in "technology" that are discussed in the paper include: larger capacity equipment new flow sheet concepts simplification of process interfaces, and more effective project strategies The common theme is that having a new idea can be the easy bit, putting it into operation effectively involves numerous people, many interfaces and strong project management.

Sep 13, 2010

By J. Samir

The objective of this study is to simulate the isothermal filling up of moulds by a RTM process when adopting CV/FEM and VOF method and when also taking into account the presence of obstacles coupled to the effect of the thickness and reinforcement layers variation. The codes developed intended to ensure an optimal positioning of the injection points and of the vents and also to determine optimal injection pressures, in order to minimize the cycle times. These codes use a mesh generator proper to the team, allowing a discretization of the domain in triangular unstructured elements, with the possibility of a local refinement and inserts inclusion.

Jan 1, 2009

By AMIRA P588 Research Team

This contribution summarises new knowledge and data, obtained during a three year ARCAMIRA funded research project, on the mineralogical and geochemical characteristics of hydrothermal alteration associated with low sulfidation, gold-silver epithermal deposits. These data are used to develop exploration vectors for use at both deposit and district scales, plus techniques have been established to distinguish ore grade epithermal systems from barren or low grade systems. Deposits investigated were Ladolam, Papua New Guinea, Gosowong and Mt Muro, Indonesia, Cerro Vaguardia, Argentina and Bimurra and Twin Hills, Australia.

Jan 1, 2005

By D. L. Petersen, C. R. Nelson, B. K. Nelson, B. D. Wagener

The Lafayette Bluff tunnel, currently under construction for the Minnesota Department of Transportation (MnDOT), will be among the widest highway tunnels in the United States. The 199-meter tunnel is being constructed in a closely jointed, variably weathered diabase rock mass. Cover above the tunnel crown ranges from 4 meters to 27 meters, and is less than the tunnel excavated width of 18.3 meters for about 60 percent of its length. These factors dictated special support and lining design, limitations on excavation sizes and required sequences for support installation. Tunnel excavation is by controlled blasting, with multiple top headings and bench. Rock support and lining consists of external portal beams, rockbolts and reinforced shotcrete. A final concrete lining provides structural support for the rock mass and the membrane waterproofing system.

Jan 1, 1991

This article updates the status of fatalities occurring in both coal and metal/nonmetal mines from January through December of 2001. Based on preliminary accident reports, as of December 31, 2001, seventy-two fatalities have occurred at coal and metal/ nonmetal mining operations. During this period, forty-two fatalities occurred at coal operations and thirty fatalities occurred at metal/nonmetal operations. Ignition or explosion of gas or dust and fall of roof were the most frequent accident classifications in coal and powered haulage fatalities were the most frequent accident classification in metal/nonmetal.

Jan 1, 2002

By Donald E. Ranta

An ore zoning technique developed by Climax geologists during the past forty years has been used to contour drill-hole assay values on cross-sections for fourteen porphyry molybdenum deposits in western North America, including the Climax and Henderson orebodies. Detailed geological studies of these large, complex deposits are essential in determining ore controls, which are the factors most critical to the zoning of MoS2 assays and to conceptualizing geologic models. The technique provides a detailed representation of the size, shape, grade distribution, and geologic continuity of the individual deposits. It demands a disciplined approach and adheres to rigorous rules while maintaining flexibility for adaptation to widely varying geologic conditions. By defining the limits that guide and control manual, computer-assisted conventional, and geostatistical reserve estimates, it exerts a strong geologic influence on the estimation process. A combination of ore zoning and geostatistical analysis of molybdenum deposits produces a significantly more accurate, precise, and defendable geologic reserve estimate than other methods.

Jan 1, 1983

By M. J. Beus

Many mines in Canada, the United States and South Africa are reaching the hoisting limit. Very little payload will be possible without compromising safety due to the excessive weight. It has been suggested (DeLorme, 2000) that one of the most attractive concepts to enable deeper hoisting is to reduce the allowable factor of safety in the wire rope. Researchers at the Spokane Research Lab are developing new technology to improve hoisting safety and productivity by providing new monitoring and analytical tools. A Shaft Conveyance Monitoring System (SCMS) has been developed which determines hoist rope end load, true conveyance position and acceleration, and rope safety factor, as well as other hoist operating parameters. This information is transmitted to the hoist operator display 20 times per second. Recent field measurements on 45 mm (13/4 in.) diameter hoist rope indicate that dynamic forces during loading of a 9000 kg (10 ton) skip could exceed the safety factor of the rope. To improve on the current understanding of the mechanical behaviour of hoist ropes, and to help interpret the results from field-testing of the SCMS, a new approach to computer modelling of stranded wire rope is also being developed. Particle Flow Code, PFC3D (Itasca, 1999), is used to simulate the structural behaviour of wire rope and the interaction between individual strands when the rope is subjected to static and dynamic end loading. Details of the SCMS, field results from the measured rope loads, and the results of numerical modelling on the wire rope will be discussed.

Jan 1, 2002

By F. Dehghani

The influence of different grinding methods on the shape characteristics of magnetite particles was investigated. Also, the effect of particle shape on the flotation of the magnetite, both alone and in the presence of quartz particles, was investigated. The shape characteristics of the magnetite particles were measured and calculated from images obtained by scanning electron microscopy via an image analysis system. The flotation tests were performed using a laboratory flotation cell. Results showed that in the -250+212 µm and -106+75 µm size fractions, ball mill products have a higher elongation value than rod mill products, while in the -150+125 µm size fraction, rod mill products have a higher elongation value. Particles with higher elongation values and lower roundness values have a higher flotation kinetic constant. Furthermore, the influence of magnetite particle shape on flotation is greater, and the flotation kinetic constant is higher, in the presence of quartz particles than in the flotation of magnetite alone Keywords shape, elongation value, flotation kinetics, magnetite.

Dec 1, 2013