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By J. Twining, V. Nguyen, J. Perera

A computer code for ecological risk assessment (ERA), AQUARISK, has been developed and applied to evaluate the likelihood of biotic detriment due to exposure to acid rock drainage (ARD) from the Burkunga mine site in Australia Stream water quality monitoring data were used for the assessment and were compared with a) national water quality guidelines, b) literature derived ecotoxicology data and c) biological monitoring data. With bioavailability calculations, the code predicted that, for metals exceeding the guidelines, 44% of macroinvertebrate species above the mine and 100% below the mine would be adversely affected by the metals in the stream. This compares reasonably and conservatively with biological monitoring that showed observed reductions of 41% and 85% of species respectively at each site. Using literature data for macroinvertebrates to predict impact produced similar estimates to using data for all taxa. Use of speciation modeling also lessened the degree of reduction in the median water metal concentrations required to achieve acceptable impact (measured either by exceedence of criteria or by species likely to be affected) by a factor of 75%. This result implies significant economic and management benefits in relation to remedial engineering or water treatment options for sites.

Jan 1, 2000

By Elli Nurminen

In this work the thermodynamics of the metallic sulphate decomposition reactions were studied through thermodynamical calculations and thermogravimetric methods. The decomposition temperatures and mechanisms were determined for cupric sulphate, ferric sulphate and also for industrial flue dust from a copper flash smelting process. The aim was to determine the thermodynamic conditions for sulphate decomposition and to estimate whether the reactions are kinetically likely to take place in the flash smelting process heat recovery equipment. The information is essential in CFD-modelling of the reactions taking place in the boiler and for optimising the process.

Jan 1, 2006

By E. L. Estabrook, H. H. Hill

This report summarizes the information that was obtained by the Committee on Unit Operation in Eastern United States and in the foreign countries. Letters and questionnaires were sent to all of the Eastern members of the Petroleum Division of the American Institute of Mining and Metallurgical Engineers and to those who are living outside of the United States, asking them to advise the Committee of any unit operations that are in effect in the various countries of the world and to furnish the names of men to whom inquiries should be directed for detailed information on the different projects. The response to the Committee's request is worthy of note. Practically all of the members who had knowledge of foreign operations replied to the questionnaire and not only furnished information that was of value to the Committee, but they evidenced a real interest in the subject of unit operations and assured the Committee of their willingness to assist in every way possible in order to make the study a success. The Committee wishes, at this time, to express its appreciation of the excellent cooperation that was received from the members of the A. I. M. E. to whom questionnaires were sent. Unfortunately, the limited time that has been given to this survey did not permit the collection of detailed data on the different unit operations that are now in effect. It required several weeks to get back replies from the members located in some of the foreign countries and as a result the men who were asked to furnish information on the various projects have not had sufficient time to submit the detailed data that were requested. The Committee has been assured, however, that information relating to a number of unit operations will be furnished in the near future. Part of the delay has been due to the fact that the purpose of the study was not understood and because the terms "unit" and "near-unit" operations were not clearly defined. In the foreign countries, practically all of the operations in noncompetitive fields are on concessions or leases that have been granted to a single company and for that reason

Jan 1, 1930

By D. M. Maijer, S. M. Mohseni, A. B. Phillion

The microstructure evolution kinetics of aluminum alloy B206 during artificial aging has been investigated using non-isothermal calorimetry. A combination of differential-scanning calorimetry (DSC) and tensile tests have been utilized to develop an Avrami model to predict the precipitation kinetics as a function of the thermal processing parameters. The Avrami coefficients, found based on a Kissinger analysis, compare well against those reported in the literature for aluminum-copper alloys. The rapid precipitation kinetics predicted by the Avrami model at temperatures higher than 200°C were assessed through a qualitative comparison against hardness measurement results. In contrast to the continuous hardening observed at 150°C, the material softens with continuing heat treatment at 250°C resulting in an overaged state. This can be attributed to the rapid precipitation kinetics at this temperature, leading to the termination of the precipitation-hardening effects at early stages of artificial aging.

Jan 1, 2015

SASOL Synthetic Fuels has recently completed the design of sampling systems for raw and blended coal feeding the gasifiers at Secunda, South Africa. The new systems will replace manual, stopped belt sampling and have been designed to achieve specific accuracy targets on a daily basis. The sampling system is unusual in the coal industry in that the fines content (-5.5 mm nominal) of the coal is very critical and is to be determined with high accuracy.The sampling system was designed to meet carefully considered target accuracies using methods of modern sampling theory. The heterogeneity of the coal streams involved with respect to the critical analytes was determined by appropriate sampling and sample analysis. The statistical characterisation of the time variation of analytes in the process streams was based on variograms derived from on-line ash gauges. From this point, the design was completed using fundamental statistical sampling theory and some simulation studies. The paper discusses the development of the sampling system design in detail as well as the plans to use the data stream to provide timely alarms when the coal quality deviates from the target specification.

Jan 1, 2002

By Michael Laing

Blasting regulation and restrictions are tougher today than ever before. When blasting in population centers, strict limitations are often placed on the environmental effects caused by blasting, more specifically vibration and overpressure. Blast-induced vibration can be a tricky thing to manage at times, but there are a variety of options at our disposal to help optimize and manage vibration. This paper focuses on the application of rudimentary signature hole analysis to optimize blasting vibration in localized areas surrounding a mine.

Jan 1, 2017

By H. P. Dibbs

An account is given of the application of neutron activation analysis to the rapid, non-destructive determination of copper in minerals, using a 14-MeV neutron source. Elements that interfere in the determination of copper by this method are given, together with the errors in the estimation of copper that result from the presence of varying amounts of these elements. The possible use of a compact "sealed-tube" 14-MeV neutron generator for the field assay of copper in minerals is discussed.

Jan 1, 1970

By B. M. Larsen

NEVER having actually tried to engage in the systematic education of anyone, and having little direct knowledge of the practical problems and limitations in the field of education, I can pose only as a "nonexpert" in this field, one whose ideas are to be regarded as personal opinions. The necessity for compromise between educational ideals and the practical limitations of time, money, and mental capacities of both student and teacher is evident in the preparation of an end product that we may regard with a reasonable degree of conviction as a professional engineer. We need to do so many things. The engineering student must have a clear understanding of the basic sciences; he should develop manual skills and co-ordination; he should speak and write the language with simple clarity and directness; he should gather knowledge of a special field; and, he should be educated for living in a broad ..

Jan 1, 1948

By K J. Davey, J T. Woodcock

Australian steelmakers produce up to 30 000 t/yr of electric arc furnace (EAF) dust. Current disposal techniques include sending EAF dust to landfill, stockpiling, and paying zinc smelters or registered waste removalists/processors to take the dust. Many of the complex overseas pyrometallurgical and hydrometallurgical treatment routes cited in the literature are not considered economic. Governmental, environmental and social pressures on producers to consider more sustainable disposal options are mounting, and there is now a strong push to consider recovering potentially valuable or recyclable components, such as zinc and iron units, from EAF dust. As well, there remain strong economic drivers for producers to find lower cost disposal solutions. Characterisation studies undertaken at CSIRO Minerals have revealed important physical differences in the nature of the zinc- and iron-bearing phases contained in domestic EAF dusts. These differences have been exploited using simple and cheap mineral processing techniques such as water washing, wet cycloning and wet magnetic separation. This has allowed a significant upgrade in the zinc content of EAF dust to be achieved, together with a reduction in the levels of key smelter penalty elements, such as chlorides and fluorides. The zinc-rich portion of the dust is now a more attractive smelter feed while the iron-rich part of the dust could potentially be briquetted or pelletised with a reductant and recycled to recover iron, and thus close the loop on dust processing. The basis of the separations tested together with laboratory results from several Australian dust samples are presented and discussed in this paper.

Jan 1, 2006

By D. A. Poukhovski

Two integral components of the 30 CFR 48 training requirements mandated for new miners, newly employed experienced miners, and the annual refresher training of all miners are hazard recognition and prevention of accidents. In these categories, instruction shall include the recognition and avoidance of hazards present in the mine, and a review of accidents and their causes. Unlike instruction preparation for fact-based material, program development for hazard recognition places a particular challenge before safety-training specialists because they are often limited in their ability to adequately gauge the trainees' levels awareness prior to training. Further, they must also assure that the training is relevant, and it is presented in a thought-provoking manner. Computer-based instruction is particularly well suited for assisting trainers in developing hazard-recognition topics because it can be used in pre-training and post-training modes for assessment of training effectiveness, in addition to use as a presentation tool. Therefore, this paper will present a recent approach developed at Penn State to apply this technology for assessment and instruction of accident prevention through hazard recognition, with an application prepared for surface coal mines.

Jan 1, 1997

By Makiko Takahashi

A tool is being developed to predict and visualize the microstructural evolution of steels during quenching. This tool utilizes experimental data and reference data that are stored in a database to predict the microstructural development. The visualization tool animates qualitative representation of two- dimensional microstructure drawings as well as the quantitative volume fractions of phases present as a function of time. This is achieved by superimposing the Jominy End-Quench test results over the Continuous Cooling Transformation diagram of the alloy. The predicted microstructure is presented through the web browser to maximize the ease of use. In addition, a parallel coordinate system is used to aid in identifying similarities within the data set by presenting the large number of data at a glance. The results for 4140 steel that was quenched in a wide variety of quenchants will be presented to illustrate the prediction and visualization tools. Keywords: Quenching, Microstructure Prediction, Simulation, Data Visualization, Database, Applet, Animation

Jan 1, 2003

By F. Bélanger, P. Fournier

"The Detour Lake Mine is located in northeastern, Ontario, approximately 300 kilometres northeast of Timmins and 185 kilometres by road northeast of Cochrane. The mill processes a free milling gold ore using both gravity circuit and leaching with a state-of-the-art carbon-in-pulp circuit. The grinding circuit is a conventional SABC circuit with a tonnage of 60,000 mtpd at 95 microns with the addition of pre-crushing upstream of the SAG mill. This paper will highlight the impact of a pre-detox thickener on the cyanide consumption in a gold leach/CIP circuit. While the pre-detox thickener was built with the intention to reduce the cyanide consumption, the opposite effect was observed when the thickener was put temporarily offline. It will show how the re-circulation of a dilute stream of cyanide into the grinding circuit, increases the overall slurry temperature and by the same effect, increases the dissolved copper concentration in the leaching circuit which subsequently increases the cyanide consumption.INTRODUCTION The processing plant is using a conventional gravity, cyanidation and carbon-in-pulp processing facility currently operating at approximately 60,000 mtpd. The comminution process is based on two parallel SABC lines, each fed from an individual reclaim tunnel. Cyclone overflow from the two ball mill circuits is directed to the pre-leach thickener. The thickener underflow is distributed to two (4) parallel leach trains of 5 tanks each, each leach train providing 29 hours of leaching retention time. After leaching, the gold in solution is recovered in a carrousel CIP circuit consisting of two (2) parallel leach trains. Tails from each CIP circuit are combined and sent to a pre-detox thickener to recover as much cyanide solution as is economically practical before being diluted and fed to a cyanide destruction system. The detoxified tailings are sent to the Tailing Management Area (TMA) for settling and retention. The excess water from the TMA is reclaimed and recycled back to the processing plant. The pre-detox thickener is designed to thicken the leach tails slurry to 64% solids with the overflow being recycled to the grinding circuit. It is estimated that the pre-detox thickener will recover 60% of the cyanide in the CIP discharge solution. It is also designed to reduce the SO2 consumption by diluting the thickener U/F to 50% solid using the tailing pond reclaim water which has very little cyanide content."

Jan 1, 2019

By WOOLSEY MCA JOHNSON

INDEPENDENTLY of the recognized chemical reactions involved in the production of metallic zinc, the process is affected by physical conditions in efficiency, and by commercial as well as technical economy. To offer some observations concerning these conditions is the purpose of the present paper. Among the important elements of this problem is the physical nature of the particles constituting the mass of zinc oxide to be reduced. This may be the result, either of the manner of the original deposition of the mineral, or of the treatment to which it has been subjected in the roasting-furnace. The physical character of the reducing-agent is another important factor, since the carbon of some coals is much more active in reduction than that of others. The degree of fineness, whether of ore or coal, or both, likewise plays a significant part. These factors, together with the physical admixture of foreign substances with the ore, may give rise also to chemical "side-reactions," sometimes hindering or retarding, and sometimes accelerating, the reduction. Finally, thermal conditions, including the relative conductivity of the materials, deserve to be taken into account. In firing a furnace with retorts charged with a mixture of roasted ore and coal, the first reaction is naturally the boiling-off of the contained water ; the next is the distillation of the light hydrocarbons from the coal; the next is the reduction of the iron oxide to protoxide and sub-oxide successively, and then to metallic sponge; and the final reaction is the reduction of the zinc oxide in the ore by the carbon to metallic zinc. This reaction commences at 1,022° to 1,060° C., according to the physical nature and condition of the coal and ore. Since the retort and the charge are far from being good con-

Sep 1, 1907

The Tuesday morning session of the Rocky Mountain Coal Mining Institute was opened at 9:00 a.m. by Bob von Storch, in the absence of the President. Mr. von Storch appointed the following new members to the Resolution Committee in the absence of three of the members: Albert Keenan, E. S. O'Connor and Howard Crandell. This committee was asked to be ready to report at the Wednesday morning session. Mr. von Storch then introduced Lyman Fearn, State Mine Inspector for the State of Wyoming, who presided over the morning session. Mr. Fearn introduced the first speaker for the morning, Louis A. Engstrom, Engineer at Kemmerer Coal Company, Kemmerer, Wyoming, who delivered a talk illustrated with slides in the absence of Mike Zakotnik, Jr., who was unable to attend. (Please refer to the index for printed text of this paper.) The next paper, "New Horizons -Coal for the Steam Plants of the West," was delivered by Don Newberry, superintendent of the Castle Gate Mine of the Independent Coal and Coke Company, Castle Gate, Utah, in the absence of W. J. O'Connor. (Please refer to the index for printed text of this paper.) Bob von Storch then introduced Edward G. Fox, President of Bituminous Coal Operators' Association, Washington, D. C., who delivered a paper on "A New Era in Labor Relations."

Jan 1, 1957

The surface of chalcopyrite was studied in situ in aqueous solution by an atomic force microscopy (AFM). The AFM images showed that some absorbate in patches was detected on the mineral surface, after the chalcopyrite sample was soaked in 5x10-4M potassium ethyl xanthate (KEX) solution at pH 11 for 10 minutes. These patches increased in size with time elapsing. At the same time, as shown by the obtained AFM force curves, the adhesion between the AFM tip and the substrate increased greatly due to the adsorption. Rinsing with ethanol removed the absorbate from the chalcopyrite surface, as well as the big adhesion observed in KEX solution.

Jan 1, 2010

By Richard S. Fowkes

This Bureau of Mines report describes the Human Factors in Mining Search System (HFMSS), a computerized information retrieval system that provides relevant human factors information from journal articles, research reports, seminars, conferences, etc. in terms of 19 mining-related categories. It is the only existing data base that stresses all of the areas of human factors as applied to mining. Examples of these categories are biomechanics and work physiology, human error and human reliability, work design and task analysis, manual materials handling and back injuries, hand tools, organizational and management practices, psychological factors, and training. Although the emphasis is on literature dealing directly with mining, applicable material from other areas of research is included for those categories in which little research has been done in mining. Each record in HFMSS can be recalled by any field such as title, author, date, source, descriptive terms or key words, as well as by any words found in an abstract that describes the purpose, procedure, and results of the research. This report describes HFMSS fields and subject categories, the annotated bibliography, user's manual, and thesaurus of key words. Example printouts in both brief and full formats are included as an appendix.

Jan 1, 1990

By R. G. Hilton

This paper deals with application of Super Detox? stabilization technology to the treatment of electric arc furnace dust (US-EPA listed hazardous waste KO61 ). The process has been used on approximately 170,000 tons of electric arc furnace dust. In addition to the nearly four years of commercial experience at Sterling, Illinois, the process is now being permitted for application at two other locations. The process was originally developed by the Bethlehem Steel Corporation and then further improved by Conversion Systems, Inc. (Bethlehem Steel's Licensee). The treatment process offers many unique bases for its selection, including: A) Low cost compared to the treatment alternatives; B) Lowest available TCLP leachate levels for any process treating K061. Many other processes leave some residue that represents a disposal requirement, although often not addressed; C) Produces minimized final waste disposed, including the fact that the total volume of dust generated and less than the volume occupied by the residue slag from HTMR; and, D) Opportunities for the beneficial utilization of part or all of the waste stream through the development of chemical and physical characteristics. Each of these aspects will be specifically discussed in the paper, including that status of the operations now under permit.

Jan 1, 1994

By Jennifer Ward

The primary objective of this paper is to establish how a low cost, high definition (HD) camera can allow for easy sustainable recordings of blasting operations. The subsequent analysis of each video can be utilized to monitor what type of performance was achieved and aids in improving blasting performance.

Jan 1, 2015

By Taghi Sherizadeh, Kutay E. Karadeniz, Dogukan Guner, Samuel Nowak

Despite numerous empirical, numerical, and hybrid studies conducted on the subject of coal rib failure, mine fatalities related to rib failures continue to occur. To date, a standard methodology for the design of coal rib supports which can accommodate the wide range of unique conditions found in coal mines in the United States has not been developed, forcing mine operators to rely on the trial-and-error process or industrial legacy practices for the design of coal rib support patterns. In this study, to better understand the support systems' effectiveness, various rib bolting scenarios were investigated. A coal mass constitutive model is implemented to a Distinct Element Method (DEM) code, and rib factor-of-safety (RibFOS) analyses were performed by applying strength-reduction for the coal matrix and explicitly modeled face cleats. Ribs with various overburden depths and mining heights composed of solid Banded-Bright coal (BBC) were considered in this study. Different scenarios such as rib bolt length and the number of bolts were studied to quantify the effect of primary rib support density on rib stability. As a result of the unsupported coal rib analyses, a decaying exponential relationship is proposed between the mining height-overburden depth and the RibFOS. The developed coal rib models clearly show the coal-rib bolt interaction and illustrate how the addition of rib bolts restricts the movement of the coal rib. The results reveal that the strength reduction method in DEM code with the coal-mass model can aid in the development of practical primary support charts, which can help in the rib support design process. In addition, an unsupported RibFOS cutoff

By W. E. Forsythe

WHEN measuring ordinary temperatures, the instrument is generally placed in very close contact with the body the temperature of which is desired. However, if the temperature of the source is continually raised, a point is soon reached where no known substance will, in general, remain constant in any of its temperature-measuring properties if placed in direct contact with the source. Also, it is occasionally necessary to measure the temperature of a source that 'is so small or so situated that it would be very hard to bring the measuring instrument into direct contact with the source. When these conditions exist, advantage is taken of the well-known fact that all bodies, when at sufficiently high temperatures, send out radiation in amounts readily measurable. This radiation has been found to be related to the temperature. The temperatures of very hot bodies have probably always been judged by the color, or the brightness, of the light given off. With practice, one can estimate probably within 50° to 100° C. of the correct value. However, if judgment is left to the eye alone, very much larger errors are sometimes made, due to

Jan 9, 1919