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By J. E. Nesset, F. Rosenblum, J. A. Finch, R. Payant

ABSTRACT Under certain conditions of moisture and oxygen, sulphides can spontaneously self-heat. We tested a hypothesis that galvanic interaction between some sulphides can promote self-heating. Galvanic interaction is controlled by the rest potential difference between sulphides and particle size. A series of binary sulphide mixtures was tested. Individual sulphides and mixtures with low rest potential difference did not self-heat, but mixtures of high rest potential difference did. When testing pyrite-sphalerite mixtures, self-heating increased inversely with particle size, with the fineness of the pyrite governing self-heating, indicating the rate-limiting step is the reduction reaction. The results support the hypothesis that galvanic interaction contributes to sulphide self-heating. A possible mechanism based on hydrogen sulphide as an intermediate product is proposed. The understanding gained will be of interest to those involved in storage, shipping, and disposal of sulphides.

Jan 1, 2012

By Hillary W. St. Clair

The reduction zone of the iron blast furnace is represented by a mathematical model of the chemical reactions and heat transfer that occurs between gas and solids during the deoxidation of iron oxide. The model consists of a set of equations and an algorithm whereby the equations may be solved to give the temperature and composition of gas and solids at any position in the reaction zone and at any time after a specified initial state. The model is applied to the special case in which ferric oxide is reduced by graphitic carbon and carbon monoxide produced by burning carbon in dry air. The rate of reduction, carbon consumption and maximum temperature are shown as functions of the temperature and rate of flow of the incoming reducing gas and external heat loss. The model of the reduction zone is the essential part of a general mathematical model for simulation of the iron blast furnace. The simulation model will serve as a research tool to be used in conjunction with an experimental or operating furnace. After the simulation model has been correlated with the real furnace, it is proposed that further experimentation be done mostly with the model. The real furnace will then be operated primarily to test and confirm the model.

Jan 1, 1967

By F. A. Auld

"Traditionally deep shaft sinking from the ground surface was carried out using drill and blast methods. Although large diameter blind shaft drilling has been carried out successfully on numerous occasions previously, including as early as 1852 in Germany (Auld, 1995), little attempt has been made until more recently to mechanise the shaft sinking excavation process using down-the-hole machines. This paper reviews the development of deep shaft sinking machines from the early 1970’s up to the present day. INTRODUCTION Mechanical excavation methods can significantly improve excavation performance, in order to access natural resources faster, and labour safety is increased compared to drill and blast operations. However, shaft sinking machines need to be capable of accommodating all the basic requirements for deep shaft sinking, namely: 1. Excavation and muck removal 2. Ground stability control 3. Groundwater ingress control 4. Temporary lining installation 5. Permanent lining installation and watertight sealing 6. Ventilation 7. Secondary means of egress for personnel In addition, how the machine operates in the shaft is an important factor, either slung on ropes from a surface headgear or on its own in the bottom of the shaft. An all-embracing machine which can deal with all of the above conditions is impossible but many of these requirements can be incorporated into a single machine. Deep shaft sinking also differs greatly from normal tunnel construction which employs the use of either a roadheader arm installed within a shield or a full-face tunnelling machine for excavation. Hydrostatic pressure and ground stability problems increase with depth, whereas in tunnelling the depth is normally relatively shallow and the aforementioned factors remain approximately constant along the tunnel length. DEEP SHAFT SINKING MACHINES All the shaft sinking carried out previously in the UK was by the traditional method of drill and blast. Elsewhere, in other parts of the world, attempts have been made to mechanise the process."

Jan 1, 2019

By Ray H. Hario

Background of Erie Mining Company Erie Mining Company, managed by Pickands Mather & Co., is one of the largest producers of iron ore pellets in the United States. The plant is located at Hoyt Lakes, Minnesota, sixty-five miles north of Duluth on the eastern end of the Mesabi Range. Taconite Harbor, situated on the north shore of Lake Superior, is the location of its Power Plant and shipping facilities. (Figure 1) Even though the plant commenced operation in September, 1957, its true be-ginning can be traced back to 1931 when Pickands Mather, in conjunction with Bethlehem Steel Corporation and Youngstown Sheet and Tube Company, began investi-gating the possibilities of processing low grade ores. In 1940, Erie Mining , Company was formed. During the early and middle 1940's, laboratory and pilot plant research was proven to a point where a preliminary plant was deemed feasible and built in 1948. This plant had an annual capacity of 203,200 t (200,000 long tons) per year and, until mid-1952, was the only taconite plant in existence using commercial-size equipment. During this period, ownership of Erie Mining Company was expanded to include Interlake, Inc. and The Steel Company of Canada, Limited. In 1953, authorization was obtained from the owners to build a 7.62 M t (7.5 M long tons) per year plant at a cost in excess of $300,000,000.

Jan 1, 1977

By Scott White, Pishun Tantivangphaisal, Andrew Bell, Chris Barker

There has been considerable advancement in recent years in the tools, both software and hardware, available to allow efficient digitalization of site records during the construction of geotechnical works. Whilst these tools have excelled at replacing handwritten records, the ability to use digital records to validate design and construction requirements in real time or even within reasonable timescales has generally been limited to the development of bespoke ‘prototype’ project specific solutions. This paper describes the development and implementation of an industry standard design schedule and the benefits of the broad adoption of a single database schema for data recorded on geotechnical sites. The former has brought significant improvements and automation of the design process, whilst the latter has enabled the validation of the constructed works against design intent in almost real time. Further details of the standardized design schedule, already publicly available in the UK through the FPS, examples and lessons learnt from implementing digital site record systems on live projects are presented herein. The utilization of cloud computing technology and complex algorithms linking plant/rig instrumentation with design data can further automate construction sites using IoT (Internet of Things) best practices. The authors will share their experience of the recent deployment of a digitalized design-to-construction record system, give recommendations for future development and a call for an industry wide drive to finalize and adopt the AGS Piling data schema.

May 1, 2022

By Rollin A. Slater

The bulk materials handling industry has served silently for years as the skeleton structure and often the central system of nerves and nourishment for the body of basic production industries. During the past two decades, this body has undergone substantial growth and mutation to meet the surging demands of our national economy for more and better products. The steel industry has been prominent in this phenomena and plants of the sixties are as unlike the second war vintage as our current crop of basketball players differ from their fathers. Steel has kept pace with spiralling demand by innovation which has resulted in new processes and improved designs which generally yield greater production from fewer units. The supporting industry of materials handling has likewise improved its techniques and currently has a new stronger generation of equipment to perform its necessary supporting function. It has been my fortunate experience to have been instrumental in the creative stages of several new steel mills which are currently in conceptual design or actual construction. Drawing upon exerpts from this experience, this paper will describe a basic approach to the selection and application of modern bulk materials handling systems to an entirely new steel plant. Specific details of past work are not available for publication, therefore, the plant described herein is a composite of ideas and will be the new plant of the Hypothetical Steel Corporation which will be located on the lower shores of the Great Lakes.

Jan 1, 1967

By N L. Turner, D J. Robinson, A J. McFarlane, N M. Chapman, L L. Kuhar, R L. Meakin, R Martin

A number of geometallurgical tests have been developed within the AMIRA P843A Geometallurgical Mapping and Mine Modelling (GeMIII) project, an interdisciplinary collaborative research project involving four research groups and over 20 global mineral companies. Researchers at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) have been focusing on the development of predictive hydrometallurgical indices for the GeMIII project via rapid, small-scale, cost-effective tests and protocols for comparative ranking of attributes relevant to leach performance. One of the focus areas has been the development of a leaching scheme for determination of the mineralogical deportment of copper in a large number of samples for geometallurgical applications.Various leaching schemes have been used over the last 20 years to identify the mineralogical deportment of copper. Typically, weak sulfuric acid and cyanide are used to target copper oxides and æsecondaryÆ copper sulfide minerals, covellite, chalcocite and bornite, respectively. Residual copper is assigned to chalcopyrite and/or bornite. Adaptations of this scheme have included the use of a weak organic acid to target oxides or ferric sulfate to target secondary copper sulfides. Testing of the weak acid/cyanide scheme in the GeMIII project using head and residue QEMSCAN mineralogical data analysed with a statistically reliable comparison method indicated that the inferred mineralogical deportment from various leaches could differ markedly from the theoretical or assumed value. Based on this initial work, test development and leach tests on samples from multiple sites has resulted in the development of a scheme to target copper oxides, chalcocite, covellite, bornite and chalcopyrite. This paper presents results from leach tests conducted on a large sample suite from two pits in a Cu-Au ore deposit with results calibrated using mineral liberation analyser (MLA) mineralogical analysis. This study has assisted in the development of a protocol for determining the mineralogical deportment of copper in a large number of samples for geometallurgical applications.CITATION:Kuhar, L L, McFarlane, A J, Chapman, N M, Meakin, R L, Martin, R, Turner, N L and Robinson, D J, 2013. Calibration and testing of a geometallurgical leaching protocol for determining copper mineralogical deportment, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 177-186 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Berk. A. A.

"INTRODUCTION Corrosion of sections of piping used in steam-heating systems is frequently regarded as unavoidable, and periodic replacement is provided. Surfaces exposed to newly condensed steam appear to be especially vulnerable to attack. As an added nuisance, solid products of the corrosion tend to accumulate, plugging return lines.The trouble is ascribed in the main to carbon dioxide and oxygen 3/ 4 / 5/ 6/ dissolved in the condensate. When oxygen is the principal factor, the corrosion usually is characterized by pitting. Carbon dioxide tend3 to cause an acidic condensate which dissolves the metal more uniformly and produces the familiar failure at threaded areas where the piping is relatively thin, and where high stress may tend to acceletate the attack. Carbon dioxide enters the system with the feedwater, generally in a combined form such as carbonates and bicarbonates. Oxygen enters both with the raw feedwater-and as air leaking into lines under partial vacuum. The larger central-heating plants have sought to reduce corrosion by eliminating these gases as much as possible. A smaller plant ordinarily lacks the equipment and technical supervision required for this purpose."

Jun 1, 1944

Four taconite plants were studied to establish the extent of hazard to plant personnel which exists based on long-term exposure to noise. The criteria for evaluation include the 90 dBA and 85 dBA summations of partial exposures. Data from extensive interviews were used to determine all work stations or locations which employees occupied and how much time they spent in ach location in a typical working day. Noise level measurements at every designated location were then made. By means of a computer program, these time and noise level data were us d to find the optimum noise reductions which would be required throughout each plant to meet both noise criteria. Subsequently, each plant was examined in detail so that the apparent sources of noise for each of the locations requiring noise reduction could be delineated. In tabular form, this report presents the hazardous locations for each plant, the existing noise level, the optimum noise reduction which would be required to meet the current and proposed laws, and the sources of noise which produce the existing noise level.

Jan 1, 1977

By John Cory, David Lily, Bill Hissem

The Lafarge granite quarry in Cumming, Georgia is using Principal Component Analysis (PCA) and Biplot charting to identify important variables and control air blast and vibration. Every blasting situation is unique and PCA and Biplot charting help to clarify the major variables determining air blast and vibration.

Jan 1, 2010

By Ralph T. Buscarello

For practical purposes, the terms "natural frequency," "resonance" and "critical speed" are synonymous. A part passing though its "critical" or "critical speed" may also be said to be "resonant" or "resonating." The vibrations of a precisely balanced part can be magnified by the structure in which it is assembled. Anyone who has driven an automobile knows that it will vibrate more at a certain speed than at others. According to the formula for centrifugal force, vibration should increase steadily with a rise in rpm. What happens instead is that the vibration not only in- creases with r m. but suddenly rises at a much higher rate through the critical speed, and then apparently smooths out as the rpm passes beyond it. To visualize what happens, consider a simple flat spring with a weight mounted at one end. When the spring is deflected by pulling down on the weight and then letting it go, the spring will oscillate, and the spring-and-weight system will vibrate at its natural frequency. If the timing or direction bf the impulses imparted to the spring did not coincide with its natural frequency, the result would be an irregular vibration that would not build up. If, on the other hand, the timing and direction of the impulses did coincide with the spring's natural frequency, the result would be a larger and larger amplitude. If the impulses were continued indefinitely, the amplitude of the spring's vibrations would go on rising [while its frequency stayed the same] until the spring broke or the amplitude of the vibrations reached an equilibrium [because frictional or other forces would tend to damp it]. Resonance magnifies the amplitude of vibrations in a relatively undamped system between 100 to 200 times over that of nonresonant vibrations. Frictional or viscous damping often reduces the magnification [from 10 to 20 times], but even with this reduction the amplitude would still be large enough to cause excessive wear, and sometimes even fractures. For example, a blower might show only 0.001 in. of vibration on the manufacturer's test stand. Installed, the blower could pass into its critical speed [the speed at which the frequency of the vibrations caused by the rotor coincides with the supporting structure's natural frequency], and the 0.001 in. of vibration could be resonated to 0.010 in., or as much as 0.020 in. The cure for such a condition would not be to lower the vibration of the blower by further balancing or better alignment but to separate the two frequencies by at least 20 to 30%.

Jan 1, 1970

By Tapio Leskinen, Jouko Koskinen, Timo Nlltti, Lappalainen Seppo, Pentti Vanninen

"The Courier 300 on-stream analysis system manufactured by Outokumpu has now been in operation at five of the company's concentration plants long enough to give a reliable basis for closer examination of the benefits achieved in control of these processes. The first system was installed at the Pyhiisalmi mine at the end of 1967. Since November 1970, two analyzers have been in operation at Pyhiisalmi feeding the assay data to a process computer which controls the whole plant and does the optimization of the process. In October 1970 the Courier 300 analysis system was installed at S. T. O. LESKINEN J. KOSKINEN the Keretti concentrator of the Outokumpu mine, followed soon by installations at the Vihanti Mine in May 1971, at the new Vuonos mine in November J 971 and at t he Kotalahti mine in December 1971. Since installation of the Courier analysis systems, considerable improvements have been achieved in the control and the economy of the plants. Immediate knowledge of the changes in the process and the possibility for rapid action has resulted in evener production and higher capacity and recovery. The recovery has been increased most significantly at the Vihanti concentrator, which operates on a complex ore. Consumption of chemicals has been reduced at all concentrators. Due to the fact that process control and partly also bilance analysis are not achieved by conventional methods any more, it has been possible to reduce the personnel of the laboratories drastically. Two of the plants, viz. the Pyhiisalmi and the Vuonos concentrators, are computercontrolled. The Vuonos concentrator started operation in January 1972 under computer control from the very beginning. The Pyhiisalmi concentrator has been computer-controlled since 1970. The Courier 300 analysis system was described in detail at the AIME Centennial Annual Meeting (1971). In this paper, less attention is paid to the analysis system. Only the sampling system of the Courier 300 is described in more detail. In the development of sampling equipment, effective use has been made of the company's wide knowledge of the problems involved and the test field offered by its concentrators. The sampling equipment includes secondary samplers and six basically different types of primary samplers, with which most sampling situations can be managed."

Jan 1, 1973

By John C. Ryan

The Emeca Pile Splice, an innovative mechanical prestressed concrete pile splice, is the first robotically welded splice to be fabricated in the United States. An analytical and experimental study was conducted to establish the capacity of the standard splice for 12-in. and 14-in. square piles. The study illustrates compliance of the splice with International Building Code (2006) requirements. A case study for a large petroleum tank foundation project in Port Canaveral, FL is presented, demonstrating the efficiency achieved through use of spliced-piles. For the case-study project, single-piece 18-in.-square, 100-ft-long piles were replaced with 12-in.-square, two-piece, spliced piles. As a result, a significant reduction of material, labor, handling, and equipment was documented for the project. Savings realized on the installed pile cost was estimated to be in excess of 30% by the owner.

Jan 1, 2010

By T Raynlyn, R J. Holmes, J R. Manuel, A Poliakov, L Lu

The prediction of sintering performance of iron ore fines and the possibility of targeted optimisation of specific sinter properties are very important for both the iron ore industry and related research organisations. Physical pilot-scale sinter runs require large amounts of raw materials and are expensive, so it is critical to target large test work programs with many different sintering parameters effectively. To predict values for sintering performance parameters such as tumble index (TI), low temperature reduction disintegration index (RDI) and productivity, a comprehensive database of pilot-scale sintering experimental results has been established and empirical modeling conducted. Similarly to earlier work, physical, chemical and mineralogical characteristics of the iron ores have been considered. However, in contrast to the previous work where only one textural parameter was taken into account, namely the proportion of dense haematite ore texture, the current model includes the abundances of several different textures which were combined into different textural factors corresponding to different sinter properties. Coefficients for the variables within specific regression equations can provide a better understanding of the effect of the variables on the corresponding sintering performance. The modelling results have also been used for predicting the sintering performance of mixtures that were not part of the database used for establishing the models. Comparison of experimental and modeling results for the verification test data is also reported in this paper.

Jan 1, 2009

By S. K. Kawatra, S. J. Ripke

Iron ore pellets use bentonite clay as binder at dosages from 0.5to 1.0% (10 to 20 pounds per ton) of moist iron ore concentrate. Bentonite is typically shipped hundreds of miles from Wyoming to the Lake Superior iron ore district. It is therefore best to know how effective a bentonite will be before it is shipped and used to bind concentrate into pellets. Current tests of bentonite effectiveness include: plate water absorption, methylene blue uptake, free swell, exchangeable cations, and glycolated layer expansion. However, these tests have many disadvantages: First, they only measure the ability of a bentonite to expand, disperse, or absorb, not how well it will bond. Second, most of the tests require up to 20 hours to perform. Bentonite only has a few minutes to interact within the concentrate before it is indurated (sintered). These long-term tests may not reflect the true behavior of bentonite. Third, the tests are tedious and often results are inconsistent between different iron ore concentrates, labs, and technicians. Fourth, some of the testing equipment is difficult to procure. Fifth, procedures are often difficult to standardize. In this paper, the Binder Effectiveness Strength (BESt) test to evaluate binders for iron ore pellets is presented that: measures the ability of bentonite to bond, requires only about two hours to complete, is simple and reproducible, and utilizes readily available equipment that has been standardized for decades.

Jan 1, 2003

By Sheridan A. Glen

As the Federal government along with individual states continue to grapple with the job of refining a comprehensive energy policy, coal continually stands out as an energy source which heralds a combination of old and new capabilities like an energy planners prophecy, but which is plagued with serious environmental constraints. To determine what level of coal utilization is ultimately possible for states East of the Mississippi, whose high sulfur content coal presents the most paramount of challenges, one must consider product availability, via existing transportation modes, the developing industrial markets and the ability of coal to meet the challenge of becoming an environmentally acceptable fuel. Gasification is emerging as a form of utilization, which during the next twenty years stands a good chance of being able to meet the challenge of making coal an environmentally clean, easily transport-able and usable fuel. It can be argued that, of all the potential ways of utilizing high sulfur coal, coal gasification is perhaps the most expensive, the most financially risky and carries environmental liabilities of its own. Synthetic gas and oil markets will undeniably be a function of price and demand, which, for the purposes of this paper, I'm assuming will begin to merge in the late 1980's and into the 1990's. This is also presuming that public utility commissions will allow favorable price structure ruling so that gasified coal products can be rolled into their respective rate base, much the same as synthetic natural gas from petroleum by-products are currently being priced. The comparative economic markets of coal to gas pro-duct have plenty of time to mature. There is an approximate twelve-year lead time needed to bring coal gasification plants on line which will be able to compete in the market place for natural gas and oil customers.

Jan 1, 1977

By G. S. Rice, H. P. Greenwald, H. C. Howarth

"""Rock-dust barriers""5 as they are termed in this country, are for the purpose of confining a coal-dust mine explosion to the limited area in which it originates. These barriers were first tested in 1910-1911, with favorable results under the conditions of test, at the French official gallery which was then at Lieven, Department of Pas-de-Calais. Shortly afterwards the Bureau of Mines in the course of its investigation of all practical explosion-prevention methods tried barriers in the Experimental Mine near Bruceton, using the primary form of simple fixed cross shelves 20 inches wide extending over the passageway and laden with rock-dust. The Bureau termed them “Taffanel barriers"" in honor of the director of the Lieven testing station. The trials were made in conjunction with tests of explosibility of different coal-dusts.Experience showed that although the principle of barriers had merit when they were used for secondary defence, the primary form was uncertain in effectiveness. This led the senior author to design mechanically discharging barriers to be operated by the compression air waves which precede the flame of an explosion. For the better understanding of the principal involved, it is pointed out that the advance air waves are what make a coal-dust explosion possible by stirring up the coal-dust from the walls and floor of the passageway. If a barrier can throw inert dust into the air to form a cloud as dense or denser than that formed by the coal-dust, it will neutralize the explosiveness of the coal-dust, and the flame of the explosion will be extinguished. When the flame ceases, the pressure dies away in a short distance if the 'area that had been traversed by the explosion is not large."

Jan 1, 1930

By George Brien, O&apos

The history of the lighting of mine workings dates back to the early part of the 18th century, when small candles known as tallow dips, were used. These were set or held in a lump of wet clay. When looking for gas the flame of. the candle was reduced to a mere glimmer by surrounding the wick below the flame with clay. The candle was then very cautiously raised from the floor toward the roof, the observer screening the brighter portion of the flame with his hand and watching for the first appearance of the pale blue cap above the flame, even at that time, known to indicate the presence of gas. When this appeared the candle was lowered quietly and its flame extinguished before attempting to drive out the gas. A very common and dangerous practice adopted at that time was to get rid of the gas by firing it. This was done by a person selected for his nerve rather than for his caution. Dressed in a? suit of dampened sackcloth or leather, this man well termed a "fireman", would lie prone on the floor of the roadway and light the gas above him by raising his candle fastened to the end of a long stick. If he survived, which was not always the case, he would withdraw promptly to fresh air after the flame had passed over him.

Jan 1, 1924

By R. V. Ramani, K. V. Raj, S. Bandopadhyay

The air flow problems in openpit mines are complex. Computational fluid dynamics (CFD) models can provide detailed information regarding air flow pattern, velocity distribution, temperature, and pollutant concentration in an enclosed domain of an openpit mine. A range of turbulent models can be selected with varying complexity and accuracy. Pollutant transport models, however, differ in their assumptions and structure as well as in the algorithms they use. As a result, predictions vary from model to model. This paper presents a study of pollutant transport in an actual openpit mine under a stable boundary layer. The objective was to test two turbulence models using similar geometry and the same input conditions and model constants. Measured data were used to compare the results of the two CFD models, namely, the kappa-epsilon (к-є) model and the Large Eddy Simulation model. Despite the complex synoptic situations, different meteorological input data and fast-changing conditions, the simulation results from both the models were in good agreement regarding the dispersion of pollutants.

Jan 1, 2015

By D. L. Griffith

THE realization by metallurgists of the important effect that traces of impurity may have upon the properties of a metal, and their steady demand for purer and still purer metals, have made the special cools for 'trace' analysis of increasing value. In the United States at least, spectrographic analysis is becoming the standard method for determining the impurities in zinc die-casting alloys. The Hudson Bay Mining and Smelting Company, as a producer of virtually pure zinc, uses the spectrograph to control the purity of its products, and-as the electrolytic method is employed here-to control both the impurities in the electrolyte and those 'trace' elements, which, while they do not contaminate the zinc, have a great effect on the plating efficiency. The general plan of the laboratory is shown in Figure l; the housing for air purification, which is on the roof, is indicated by broken lines. One of the chief factors affecting the layout was the easy way in which a spectrographic assay can be spoiled by contamination. To minimize the quantity of dust tracked in, the laboratory was made separate from the general research laboratories, and an office was placed between the two. This arrangement has its drawback because of the traffic through the office, but it has effectively cut down dust. For similar reasons, the available space was subdivided into a number of small rooms, and the air currents in the laboratory were so arranged that dust would be carried where it would do least harm. Air is drawn in at the roof over a 50-kilowatt bank of Calrod heaters, through Annis air filters, by a No. 4 Sirocco fan. Most of it is forced into the spectrograph room, but some goes to the office and darkroom. The air flow is from the spectrograph room, through the plate-measuring room, into the chemical laboratory, where it is exhausted by a No. 1% Sirocco fan on the fume hood. Air can also re-circulate from the plate-measuring room back to the heater. The arrangement is such that the air in the laboratory is maintained at higher pressure than the outside air; consequently, no dirt enters through cracks about the windows and doors. A thermo-regulator holds the temperature constant within one or two degrees; only on the hottest days in summer does the temperature rise enough to affect the focus of the instrument.

Jan 1, 1940