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By A. T. Iannacchione

From 1990 to 1996, 16 states reported 92 injuries from falls of roof, rib or face in the more than 90 underground stone mines in the United States (Fig.1). Missouri, Pennsylvania and Kentucky accounted for 48% of the total number of injuries (Fig. 2). Of this total, 11 miners were killed. Of the 11 fatalities, 10, or 91%, were associated with unrecognized loose or failed rock within the roof beam. Additionally, unrecognized roof beam failures resulted in a majority of the falls of ground injuries occurring in underground US stone mines from1990 to 1996. This number is not large in magnitude. But a workforce of fewer than 2,000 miners makes for a high fatal-accident rate. The severity of the typical fall-of-ground injury is, in general, very high. About three-fifths of all roof, face and rib fall injuries were designated by the US Mine Safety and Health Administration (MSHA) as some kind of lost time accident. MSHA assigns each accident a severity value from one to six. A one represents a fatality, a two, a permanent disability and three, a lost time accident (Fig. 3).

Jan 1, 2000

By J. G. Conaway, P. G. Killeen

"Gamma-ray spectral logging, a useful technique for uranium exploration and evaluation, has generally been underutilized by the Canadian mining industry. Provided that the technique is properly applied, it is capable of yielding reliable quantitative information regarding the distribution of uranium and other radioelements along the borehole under most conditions.In practice. there are numerous factors which potentially can degrade the quality of the log and thus any quantitative interpretation based on it. Fortunately, the appropriate choice of logging equipment and technique can avoid many such problems, and corrections can be applied to the data to compensate for most of the others."

Jan 1, 1980

By M. R. Geer, H. F. Yancey

Although the use of dense suspensions for coal cleaning was pioneered in the United States with the Chance sand flotation process, and during the past year a pilot plant using a magnetite suspension has started operation in this country, the more recent developments in this field of coal cleaning have occurred principally in the Netherlands. During the thirties the Dutch developed the Barvoys process, in which a medium of barite and clay is employed, the Tromp process, which utilizes a magnetite suspension, and the Loess process, in which is used the air-borne earth or soil known as loess.1-3 All these processes are finding increasing use in European coal-cleaning practice. Now a fourth process, the cyclone cleaner, is under development by the Netherlands State Mines. A cyclone thickener for reclaiming and thickening the dense suspension is a novel feature of the Loess process. Through accident, the discovery was made that the cyclone could be utilized as a cleaning device for fine coal. When the cyclone thickener at the Maurits mine plugged, the overflow was found filled with clean coal free of refuse, and from this observation developed the concept of the cyclone as a coal cleaner. In June 1945 the cyclone cleaner was observed by one of the authors,' and in September 1945 it was described by Dries-sen6 in a paper presented in London before the Institute of Fuel. As the cyclone seemed to offer unusual promise as a means of extending heavy-medium cleaning to the finer sizes of coal that cannot readily be treated in existing heavy-medium processes, the Bureau of Mines, following Driessen's, presentation, launched an investigation of the cyclone as a coal cleaner. Added impetus was given to this study by the present increased interest in heavy-medium cleaning in this country. Object and Scope of Investigation Driessen's report, although comprehensive in many respects, did not include a detailed description of the cyclone cleaner, and contained almost no information on the influence of the various operating variables of the cyclone. It was necessary, therefore, to investigate the influence of the cyclone adjustments on its performance before studying the application of the cyclone to various coal-washing problems. The present report is confined entirely to these preliminary tests, designed to demonstrate the operating characteristics of the cyclone. The investigation has been in progress

Jan 1, 1949

By C. W. Lee

"Introduction of diesel engines in underground mines may generate severe health hazards associated with exhaust contaminants. One of the most important parameter in determining the optimal air quantity for hazard reduction is the exhaust dispersion. Through analyzing the exact solution of the diffusion equation and its approximation by finite difference method(FDM) , this paper aims at doing a fundamental research to find an efficient dispersion model suitable to the domestic mines. Diffusion coefficients are likely to be small in the underground airways with high ventilation resistance. This makes concentration profiles similar to the convection-based step functions. It is the case for fixed as well as moving engines. Concentration estimation by exact solution is almost impossible in the case of either a single engine moving at a variable speed or the existence of multiple engines. Application of FDM to the diffusion equation including turbulent dispersion results in the various problems; unstable concentration profiles depending on the engine location, nuctuating concentrations near the engine, and overestimation of the dispersion region of which error grows with waning diffusion coefficient.Convection-based dispersion model is found to fit well for dynamic simulation of exhaust dispersion from multiple diesel engines in the airways showing low diffusion coefficients. Its suitability is more likely in the regions with frequent equipment passage. Published"

Nov 1, 1995

Discussion of the paper of H. R. Barnhurst, presented at the New York Meeting, October, 1913, and printed in Bulletin No. 82, October, 1913, pp. 2523 to 2532. H. R. BARNHURST :-I would say that in that experimental furnace we were trying to adopt the proper form for burning low-volatile coal. I was enabled on one occasion to burn coke having 15 per cent. ash. Tailings, or washings from the preparation of coal for by-product coke ovens, which came to me 52 per cent. ash, were burned without any trouble. So that ash really might be regarded as not burning, but simply diluting the fuel that was there, without doing any particular harm except that we had to put in more of the material to get the same quantity of heat. With anthracite, I burned coal right along with from 24 to 27 per cent. ash, but it took a furnace of peculiar form in which the products of combustion had to be diverted to the point of entrance of the fuel. With an ordinary furnace the fuel is deflagrated by its surroundings as soon as it enters the furnace. In a cement furnace this action is secured by the hot clinker passing clown, and the walls of the kiln are heated upon contact with it, revolving as they do', so that deflagration occurs very quickly in a cement kiln. Deflagration would occur very quickly in an open-hearth furnace also. There is no trouble in burning anthracite coal under those conditions for three or four days successively. It should be very well dried and thoroughly pulverized. Aside from that, there is no trouble. WILLIAM A. EVANS,* Boston, Mass. :-In a 52 per cent. ash, or any high-ash coal, what disposition is made of the ash ? MR. BARNHURST :-Most of it went out through the flues. Some of it remained in the boiler and a quantity remained in the furnace. We raked it out and carried it away. MR. EVANS :-Do you experience the forming of stags in flues with such coal as that?

Jan 12, 1913

By Hans U. Bartholet

The bentonite industry in Europe includes both the smectite and hormite groups of clay minerals. The smectites are, essentially, a compendium of cationic differentiatable montmorillonite platelets which can be expanded in liquid media, whereas, members of the hormite group are characterized by fibrous and chain structured lattices which are non-expandable. As was pointed out in the March '78 issue of Industrial Minerals, each of the minerals in these groups has acquired a variety of names due to historic or regional usage.

Jan 1, 1979

By Natalia Konstantinova, Georgy Novikov, Pavel Rekant, Goergy Cherkashov, Olga Bogdanova

The economic interest of oceanic ferromanganese crusts and nodules is determined by high grades of major, rare and earth rare elements in these types of marine minerals [1]. Modern oceanic ferromanganese deposits have a global distribution with the largest fields in the Pacific Ocean. The Arctic Ocean still remains a poorly explored region. The first ferromanganese deposits from the deep part of the Arctic Ocean were recovered almost at the same time in 2012 both in US and Russian cruises to the Chukchi Borderland (1) and Mendeleev Ridge (2). Preliminary results of mineral deposits from the first area were reported at UMI-2012 by James Hein et al. [2]. We present here the data of ferromanganese deposits from the Mendeleev Ridge.

Sep 1, 2014

By S. G. Valentine

BLAST-FURNACE blowing engines are broadly of two main types: either steam- or gas-driven reciprocating engines, or turbine-driven rotary engines. Some results of experience with a furnace blown by an engine of the latter type may be of sufficient general interest to relate. The first engine of this type was installed at Oxford Furnace, New Jersey, before the writer's connection with this plant, in March, 1910. This furnace uses chiefly New Jersey magnetites and had been in blast seven months on its old engines when the turbo blower was started. It was 80 ft. high by 17 ft. 6 in. bosh and 11 ft. hearth diameter. It is of interest to see from the records what happened when the turbo engine was put to work. But of course, as the old blowing equipment was rather antiquated, consisting of two I. P. Morris engines with air cylinders 72 by 72 in., in good running order, however, it is evident that the comparison between their work and that of the turbo blower cannot be interpreted as being between machines that were respectively of equal excellence as representatives of their types. Still the results were gratifying and -interesting. The records show that, with the old engines blowing 13,630 cu. ft: of air per minute, measured by piston displacement, the furnace was working up about 480 tons of stock per 24 hr. and producing an average of 132 tons per day and a maximum of 166 tons. The rotary blowing engine installed was a General Electric Co. machine, the driving end being a Curtis steam turbine and the air end a six-stage rotary compressor, all running at about 1,500 to 1,600 rev. per minute, and having a capacity of 25,000 cu. ft. of air per minute up to 25 lb. pressure, and equipped with an automatic constant-volume variable-speed governor. After running this blower, for a period equal to that covered above by the old engines, at an average rate of 15,000 cu. ft. of air per minute, the furnace worked up an average of about 592 tons of material and produced an average of 170 tons per day. Thus, on an apparent increase of 10 per cent. in the air volume there was an increase of about 23.5 per cent. in the materials worked up and of about 28.8 per cent. in the product. For the first calendar month's operation of the turbo blower, on an average of 15,040 cu. ft of air per minute, there is

Jan 2, 1914

By G J. Corbett, T M. Leach

Approximately 42 t of mercury were produced from Puhipuhi from the late nineteenth century until the end of World War II, with no significant gold or silver production. Sinter, eruption breccias and veins, mined for mercury at Puhipuhi and essentially barren of gold, are inferred in many geological models to represent the surficial levels of adularia-sericite style low sulfidation gold-silver systems. These systems may contain economic gold-silver mineralisation at depth. Conceptual geological models have been employed at Puhipuhi in the search for buried gold mineralisation. Homestake Mining utilised a McLaughlin model for exploration from 1982 to 1987, targeting mainly the vicinity of the sinter deposits. From 1987 to 1989 BHP sought deeper structurally controlled gold mineralisation within the basement greywackes, utilising models derived from studies of Round Mountain, USA and Hishikari, Japan. Macraes Mining Company Limited have accessed the previous work and applied a conceptual geological which invokes a north-south structural control for the emplacement of high-level felsic intrusions at depth. Dextral movement on these structures associated with oblique convergence facilitated the formation of a pull-apart basin in which lacustrine sediments overlie basement greywackes and are in tum overlain by Pliocene basalts. Continued activation of the NS structures created a series of inferred NE-trending dilational structures, which are targeted as fluid upflow centres for the surficial outflows. Upflows occur as eruption breccias (e.g., Plumduff) and outflow as silica sinters (eg Mt Mitchell, Williams) which are also partly obscured by the basalt cover. Argillic alteration and mercury mineralisation occur at elevated crustal levels (eg Puhipuhi mine). Modelling from structure and alteration zonations have targeted a fluid upflow in the vicinity of Bush Hill, which was not accessed by previous workers. This target was subsequently supported by surface geology and multi-element soil geochemistry.

Jan 1, 1997

By Christophe Bragard, Jason Choi, William H. Hansmire

This case history provides a physical benchmark of tunneling technology progress comparing an old hand-mined tunnel to a modern 20-ft-diameter EPB TBM that mined in the same ground. This rare opportunity to see how tunnels were constructed many years ago occurred when an old 10-ft-diameter storm drain tunnel in the way of os Angeles subway construction was demolished and replaced with obas berglass pipe. Steel rib and lagging initial support was exposed showing solid-sawn 2" × 12" × 48" redwood lagging. This paper documents the as-built old tunnel, how it was successfully replaced, and some lessons learned.

Jun 23, 2024

By C. P. Proctor

WESTERN Pennsylvania, eastern Ohio, and Illinois are carrying out experiments wherein much more slate and other impurities are loaded with the coal in the mine and hauled to the surface preparation plant for removal. In general everything is sent to the cleaning plant although there may be some gobbing in the mine. No conclusions have been announced as to the effect of such a mining system on clean coal costs. Such factors as ability of the surface plant to handle the impurities, land and facilities for disposing of the impurities, and the transportation facilities underground should be considered.

Jan 1, 1942

By Meyer Steinberg

"Some early experiences of a Cooper Union Chemical Engineer on the Manhattan project and his latest studies on CO2 Greenhouse Gas Mitigation Technologies are presented. Mitigating Global Greenhouse effect while maintaining a fossil fuel economy, requires improving the efficiency of conversion and utilization of fossil fuels, use of high hydrogen content fossil fuels, decarbonization of fossil fuels and sequestration of carbon and CO2 applied to all energy consuming sectors of the economy including electric power generation, materials production, transportation and industrial domestic heating. Decarbonization means removal of carbon as C or CO2 either before or after fossil fuel utilization and sequestration means long term disposal of C or CO2. The review will cover the principles of removal and recovery from power plant, stacks, the oceanographic and geological disposal of CO2 and the conversion of CO2 to gaseous and liquid transportation fuels. The global economic aspects of CO2 mitigation technologies are touched upon.IntroductionThis is an odyssey of a chemical engineer. My career started with the production of U235 at the Gaseous Diffusion Plant in Oak Ridge, Tennessee and the production of PU-239 metal at Los Alamos on the Manhattan Project. After 40 years at Brookhaven National Laboratory, I wound up performing studies on CO2 mitigation technologies. The following is a power point presentation on the subject of global warmingThe DOE is proposing to increase its sequestration development program in order to maintain the utilization of our vast resources in coal both for power and for transportation fuel production. Congress is considering steps to promote energy efficiency in attempts to solve not only the CO2 problem, but also the prime problem of energy supply. We will be promoting increases in energy efficiency as time goes on."

Jan 1, 2008

By B. M. Andreas

PRIOR to 1934 all haulage of ore and stripping on the Mesabi Range was by rail. Early rail systems had small narrow-gage locomotives with correspondingly small dump cars. These trains were replaced with larger standard gage rail systems powered by steam locomotives ranging up to 224 tons in weight, which have in turn been replaced by diesel electric locomotives. Along with this development cars have been increased to 30-cu yd capacity. Improvement of cars includes alloy steel construction for lower over-all weight and use of roller bearings to decrease rolling resistance. Despite all of these developments, the total material hauled by rail on the Mesabi Range has decreased every year. Yet, this is no reason to believe that rail haulage is becoming obsolete. Its adaptation to small mine operation has become impractical, but in large mines where normal railroad grades are possible or where hauls to plants or dumps are long, rail haulage is still one of the most economical methods of transporting large quantities of material.

Jan 1, 1954

By Alexander L. Field

This paper contains an account of experimental results obtained in an extensive investigation of steels containing zirconium. There recently appeared' an announcement by F. M. Becket, at whose suggestion and under whose general direction this investigation was made, a statement of the outstanding features of the work and a brief explanation of the factors that led to its inception. It is not possible, in a paper of this character, to record all of the operating and test data collected, which includes the production of more than 350 heats of steel. The difficulty of a complete presentation is increased by the fact that several lines of experimentation are too incomplete to warrant publication of the results at the present time. In addition to the methods of manufacture and test employed in the work, there is described experimental evidence on which are based certain definite conclusions regarding the remarkable effects brought about by the presence in steel of relatively small percentages of zirconium. When added to a molten steel bath, zirconium combines chemically with dissolved oxygen, nitrogen, and sulfur, in the order named, and is capable of neutralizing the embrittling effect of phosphorus in whole or in part; although in the case of phosphorus there is no evidence so far of actual chemical combination. These effects arc not in the nature of suppositions supported by theory, nor is their existence deduced merely on the basis of analytical evidence. In each phase of its relation to or reaction with the four impurities mentioned, zirconium affects beneficiauy the mechanical properties of the steel to which it is added, in a manner which it is one of the purposes of this paper to explain in terms of a tentative working theory.

Jan 1, 1923

By Alexander L. Field

This paper contains an account of experimental results obtained in an extensive investigation of steels containing zirconium. There recently appeared' an announcement by F. M. Becket, at whose suggestion and under whose general direction this investigation was made, a statement of the outstanding features of the work and a brief explanation of the factors that led to its inception. It is not possible, in a paper of this character, to record all of the operating and test data collected, which includes the production of more than 350 heats of steel. The difficulty of a complete presentation is increased by the fact that several lines of experimentation are too incomplete to warrant publication of the results at the present time. In addition to the methods of manufacture and test employed in the work, there is described experimental evidence on which are based certain definite conclusions regarding the remarkable effects brought about by the presence in steel of relatively small percentages of zirconium. When added to a molten steel bath, zirconium combines chemically with dissolved oxygen, nitrogen, and sulfur, in the order named, and is capable of neutralizing the embrittling effect of phosphorus in whole or in part; although in the case of phosphorus there is no evidence so far of actual chemical combination. These effects arc not in the nature of suppositions supported by theory, nor is their existence deduced merely on the basis of analytical evidence. In each phase of its relation to or reaction with the four impurities mentioned, zirconium affects beneficiauy the mechanical properties of the steel to which it is added, in a manner which it is one of the purposes of this paper to explain in terms of a tentative working theory.

Jan 1, 1923

By Ki-Bok Min, Seokwon Jeon, Seung-Beum Choi, Taehyun Kim

"In order to investigate anisotropic characteristics of Boryeong shale in Korea, which clearly shows transverse isotropy, a series of experimental tests were carried out. Using Brazilian test, five elastic constants and tensile strength of the shale were evaluated. Elastic constants were determined by iterative procedure and in order to perform this procedure, constitutive model was modified to fit the experimental condition. The anisotropic ratios of elastic constants were evaluated and the applicability of the methodology was assessed. Apparent Brazilian tensile strength profile was investigated and the ratio of the maximum to minimum tensile strength was estimated. Results showed that the tested rock type had low to moderate anisotropic characteristics.INTRODUCTIONMechanical, thermal and hydraulic characteristics of many rocks vary according to direction, which is known as inherent anisotropy, and it is originated from stratified and/or foliated structure of intact rock and discontinuity of rock mass. Anisotropy is one of the long standing issues of rock mechanics field and it has to be taken into account in several engineering fields such as civil, mining and petroleum engineering. An anisotropic medium has 21 independent elastic constants without any assumption of symmetry. If a material has any symmetry, the number of elastic constants required to define its behavior reduces and eventually two constants are necessary if it has complete symmetry, which is known as isotropy. An anisotropic medium that has remarkable planar structure due to its stratification and foliation such as bedding is often called as a transversely isotropic medium. Transversely isotropic model is frequently adopted in many applications especially for sedimentary rock formation and five elastic constants are required to establish the constitutive model."

Jan 1, 2015

By K. Morsi

Carbon nanotube (CNT) reinforced metallic composites have been recently generating significant scientific interest, due to their expected superior properties compared with other composites. Out of the metallic matrices investigated for reinforcement with CNTs, aluminum has received considerable attention. A major problem has been the dispersion of CNTs in metallic matrices. This paper discusses preliminary results on the mechanical dispersion of CNTs in aluminum powder, powder processing, stability and characterization of aluminum dispersed with CNTs at reinforcement levels equal to and below 5 wt.%.

Jan 1, 2009

By Stephen Krickovic

"Bleeding", as used in mine ventilation language, has a number of meanings among mining men and is regarded with different degrees of importance. This lack of uniformity stems from a number of specific situations. A method that is adequate in a mildly gaseous mine may fall short in a very gaseous mine. Projected bleeders could be dependable under a certain type of roof, and totally unsatisfactory under a different type. Similarly a plan of bleeders can be rendered useless due to undulations of seam and water in one mine and function well in another. Finally, what is effective in a mining system with partial recovery will not suffice with full recovery. You may wonder, then, if there is a common denominator for the essential function of "bleeding". In my opinion, there is, and it can be defined as controlled movement of air across an active pillar line toward the back and outby ends of the adjacent gob area into the headings provided for the purpose. The objective is to maintain as methane-free as practicable a belt adjacent to the working places, so that, if face ventilation is interrupted temporarily, the gas will not accumulate in dangerous volumes at the working faces before ventilation is restored. It's possible for these temporary interruptions to be unnoticed in time or at all. In such cases, ineffective bleeding could cause a disaster. This has happened. To control, there must be power. That is to say, there must be adequate air, pressure differential between the front and back ends of a pillar line to facilitate proper regulation for diverting of air to the various portions of the gob and as far away from the active section as is practicable. As an indication of the importance of pressure, it is noteworthy that one may provide and maintain in a reasonably open condition a heading or two for a bleeder system and fail to obtain effective bleeding .because air pressure differential is inadequate. On the other hand, you are all familiar with the fact that pillar lines in some seams can be ventilated adequately by air flow straight across the gob when the section is near a main return shaft and thus obtains a heavy pressure differential.

Jan 1, 1962

By G F. Brent, S Hawke, M Rothery, P Dare-Bryan

Mine-to-mill studies have previously demonstrated downstream productivity benefits from relatively modest increases in blast energy, or powder factor. These increases have up to now been limited by safety and environmental constraints, since excessive blast energy can result in flyrock, unacceptable vibration, airblast and wall damage.Here, a new blasting method that overcomes these constraints is presented. For the first time it is possible to employ powder factors that are several fold higher than conventional blasting. Independent modelling has shown that such powder factors can potentially increase mill throughput by 20 to 40 per cent. The economic implications are substantial, both in terms of increasing production in existing operations and in consideration of capital and plant requirements for greenfield sites. In addition, mill electricity and grinding media consumption and their associated costs and energy and emissions penalties can be reduced.This method represents a step-change in blasting practices. It involves a novel design utilising dual blast layers within a single blast event, all initiated with state-of-the art electronic blasting systems. The energies in the lower layer can be as high as five times the standard energies, providing for intense fragmentation of the ore. Results from blast models have been confirmed in field trials of the method.Open cut gold mining, in particular, stands to benefit from this method. As gold grades decline, milling costs and throughput increasingly become constraints on production that can be alleviated with this new method. Additionally, it opens possibilities for improved recovery. Blast modelling studies show that dilution of gold ore within the blast can be managed with the new method. Furthermore, it has been shown that vibration from the new method is actually lower than from conventional blasting, allowing the use of the technique in proximity to mine highwalls and other key infrastructure such as underground orepasses.It is concluded that this new method could substantially increase gold mine production and profitability while reducing overall energy consumption and associated emissions.CITATION:Brent, G F, Dare-Bryan, P, Hawke, S and Rothery, M, 2013. Ultra-high-intensity blasting - a new paradigm in mining, in Proceedings World Gold 2013 , pp 395-400 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By H. LeChatelier, B. Bogitch

Page Introduction........................... 134 Methods of Investigation....................... 135 The Tridymite Network...................... 137 Independent Variables....................... 146 Manufacturing Operations..................... 153 Introduction Silica brick are indispensable in the manufacture of steel because they alone are able to withstand the high temperature of regenerative furnaces. All attempts to replace silica brick by other refractory materials for this purpose have failed, but the reason for this failure has remained obscure; we shall give an explanation later in this paper. Before the war, silica brick employed in France came principally from abroad, for which reason, since the beginning of hostilities, certain French steel works have been seriously handicapped. Our attention was first directed to the question by M. Bied, Engineer of the Teil Works. With him, we began certain investigations, at first using our laboratory and the furnaces of neighboring steel works. The larger part of our experiments, however, have been made in the laboratory of the Faculty of Sciences at the Sorbonne. For the heating of our samples, we are deeply obliged to MM. Charpy, Yeatmann and Guerineau. In undertaking these studies, our first aim has been to render assistance to French industry, by indicating, as precisely as possible, the necessary conditions for the manufacture of high-grade brick; but at the same time me have

Jan 1, 1919