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By T. W. Camm, J. C. Johnson, S. D. Rosenthal

"Most engineers are bright, hard-working, reliable and prefer to avoid conflict. An engineering curriculum tends to self-select these characteristics. By most standards, you would expect workers exhibiting these traits to require minimal supervision. But, is this true? Is this how most current engineering managers lead? Looking at some current theories on leadership combined with personal anecdotes, this article will look at some common misconceptions about leading engineers.Engineers are different. There, it has been said. From cartoons to movies to television shows and more, there is a reason stereotypes of engineers resonate. Yes, you can find a lot of individual variation among specific engineers that you may know, but they do not detract from some of the overarching commonalities that engineers are known for.Clash of culturesWhat distinguishes a professional? Raelin (1985), in his book Clash of Cultures, describes professionals as having superior intellectual training, maintaining their own standards of excellence and being supported by associations that maintain the quality of the profession. Engineers obviously fit all three of these ideas: an engineering degree is still regarded as one of the most difficult to attain. Standards are maintained both through peer review and in academia, through ABET accreditation and through professional associations like SME to promote the discipline and foster technical growth.Six characteristics representing professional status are described by Raelin (1985, p. 9):• Expertise — prolonged specialized training in a body of abstract knowledge.• Autonomy — the freedom to choose the means to solve a problem.• Commitment — primary interest is in pursuing the practice of one’s own chosen specialty.• Identification — identifying with the profession and with fellow professionals, both through formal associations and through peers external to the organization.• Ethics — providing service without concern for oneself or without becoming emotionally involved with the client.• Standards — committed to help in policing the conduct of fellow professionals."

Jan 1, 2018

In this work, the crystallization of Carnallite from waste brine of Qaidam Basin in Qinghai province was studied based on NaCl-KCl-MgCl2-H2O phase diagram. According to this study, a new crystallization pathway to recycling waste brine was developed. The carnallite salt was formed by using this technology during the waste brine evaporation. The experiment data shows that 5 tons of waste brine was required to form one ton of the carnallite. The average grade of carnallite prepared by using this procedure was about 19.40% of KCl, 16.92% of NaCl, 28.80% of MgCl2, and 0.82% of CaSO4. This study provides an opportunity to utilization of the waste brine.

Jan 1, 2012

By Walter J. Johnson, Robert L. Chufo

A unique non-contracting coal thickness measurement technique has been developed to measure both the dielectric constant and thickness of a coal seam as part of a sensor array supporting an autonomous coal mining machine. The sensor measures the reflection of an electromagnetic signal from the coal/shale interface. Underground measurements of coal 6- in thick with a dielectric constant of 4 have been confirmed. Measurements were also made of a 31-in thick coal pillar for application of the sensor to highwall mining. The electromagnetic measurement technique, the data reduction process and field test experience will be presented.

Jan 1, 1992

By Tian Sugui

By means of the measurement of the enduring property and microstructure observation, an investigation has been made into the influences of the element Re and TCP phase on the enduring property of the single crystal nickel base superalloys. Results show that the needle-like TCP phase is precipitated along the <110> orientation on {111} planes in Re-containing/free superalloys during the long term aging, the TCP phase is identified as µ phase, and the precipitated µ phase in 4.5%Re alloy is gradually spheroidized during aging. Thereinto, the needle-like µ phase may obviously decrease the enduring lifetimes of the alloys due to the consumption of the refractory elements and the effect of the stress concentration. But the stress concentration is not easily generated in the regions near the spherical-like µ phase, which is a main reason of reducing the enduring lifetime of 4.5%Re alloy to a small extent.

Jan 1, 2010

By A. O. Dufresne

WITHOUT transportation, mining would be quite impossible. Any person familiar with the operation of a mine knows full well that from the minute ore is blasted, it is kept moving until it reaches the treatment plant. In the mill, by means of conveyors and elevators, the ore is brought from receiving bins to one machine after another until finally its valuable mineral is separated from the gangue. The finished product must then be shipped -either by boat, rail, or motor trucks to industrial centres, where it undergoes further treatment and transformation into finished commercial goods. Everybody appreciates that the winning of an or-e includes, amongst various operations, the moving of large quantities of material of generally low value. Transportation, therefore, must be considered One of the most important factors in the economics of mining. My assignment, this afternoon, is not to treat of that phase of transportation as it directly affects mining operations, but rather to consider some of the aspects of overland transportation and its influence in bringing about the development of mining camps in Canada. I shall take the liberty of rapidly surveying conditions facing prospectors, mine developers and operators from the time a region is still in a pre-pioneering stage until such time as a mine starts shipping its concentrates.

Jan 1, 1956

By R. C. Milici

Historical production data and reserve decline rates can be used both to predict future coal production rates and to estimate when the reserve will be depleted. Reserve estimates inferred herein from historical production data and decline rates are commonly lower than estimates made from geologic data. The latter include significant amounts of lower quality (deeper, thinner, higher sub) coal which may be mined when the better deposits are depleted.

Feb 24, 1997

By Roger Frank

"Abstract After noting the importance of standardization for piles, the European system is described (execution, tests and design, etc.). Some important aspects of Eurocode 7 are outlined (like the role of pile load tests). Finally, the calculation methods in the recent French standard for the design of piles following Eurocode 7 are shortly addressed.Importance of standardization for piles Like for other fields of geotechnical engineering, pile engineering is a complex art. For piles, the challenges are particularly numerous and many things must be mastered properly: - the soil investigation must be serious and adequate (for instance, deep enough!);- the choice of the pile type and the assumed behaviour must be assessed in order to reach a safe and economic design of the overall foundation;- the execution itself (construction and/or installation) deserves special attention and must follow strict state-of-the art rules.The geotechnical engineer, in charge of the design of a pile foundation, must have in mind the parameters linked to the variety of soils, of soil conditions and of pile types. A wide range of strong environmental issues are also to be considered: minimum disturbance during the execution processes, long-duration friendliness of the “inclusions” into the ground (to avoid pollution of the soils and waters, for instance) and respect of the neighbouring structures.Pile engineering plays in a world which is constantly moving and progressing: constructions expand in new difficult areas, actions on piles are more and more important, new execution techniques of piles are developed, research into the complex behaviour of pile foundations has no end, etc. Our views on how piles and group of piles really work are constantly evolving!"

Jan 1, 2014

By A. Manohar Rao

Underground mining in general and more so the coal mining is a hazardous venture as it is a struggle against nature and natural forces. The stability of roadways has a direct impact on production and productivity. The roadway stability can be strongly influenced by the direction of the drivage. The stress studies are useful to provide a frame work for understanding the influence of drivage direction on roadway conditions, and to illustrate how mapping techniques can enhance this understanding. The act of mining can concentrate and re-orient the original stresses. Whenever coal is removed, the overburden weight that it carried is transferred. Vertical stresses are similarly affected when the roof is deformed or failed. The Singareni Collieries Company Ltd., a joint Public sector undertaking of the Government of Andhra Pradesh and India is conducting coalmining operations in the Godavari Valley Coalfield and is catering to the needs of a large part of South India. With the technology update, it is looking for safe mining and to achieve higher production. As a part of this, an attempt is made to understand the stress conditions prevailing on the mine blocks by different ways and means in terms of geology, structure and tectonics of the Godavari Valley coalfield, satellite imagery studies, cleat pattern, stress measurement studies conducted in different mine blocks, and stress mapping technique.

Aug 1, 2013

By David S. Yantek, Paul Jurovcik, Eric R. Bauer

Workers in coal preparation plants, where vibrating screens are significant noise sources, are often exposed to sound levels exceeding 90 dB(A). The National Institute for Occupational Safety and Health, a major coal company, and a vibrating screen manufacturer conducted a cooperative study of vibrating screen noise. Rubber isolators reduced sound levels by 1 dB. Urethane screen panels did not reduce sound levels in this case. Drive noise was determined to be the dominant noise source on the screen. Damped side plates reduced vibration levels on the screen sides by 1 to 7 dB(A). Detailed results of the study are presented.

By V. I. Ryaboy, S. A. Kondratyev

"The paper describes influence of desorbed species (DS) of a number of xanthates and higher dialkyldithiophosphates on the collective ability of these reagents. Adsorbed on mineral DS of the reagents in the form of products of non-stoichiometric interaction between xanthates and heavy metal salts can pass to the gas–liquid interface and remove liquid from the layer between mineral particle and water surface. A high-speed video recording displays the process of spreading of DS of xanthates and dialkyldithiophosphates over water at the moment of local rupture of the water layer. Expansion of “dry” spot on the mineral surface after DS of xanthate capture and displace liquid from the layer has been proved with video images. The comparative analysis of collecting ability and dynamic surface activity of dialkyldithiophosphates shows that these characteristics are in good correlation. The forces exerted by spreading film of the reagent’s DS on liquid in the water layer are evaluated, and the water flow rate from the layer is determined. The line of the reduction in thickness of the water layer behind the front of spreading film of DS of dialkyldithiophosphates and xanthates coincides with the line of the increase in their dynamic surface activity. Their force on the liquid volume in the water layer characterizes collecting ability of the DS film of xanthates and dialkyldithiophosphates. It has been supposed that the collecting ability of DS of a reagent is a part of its overall flotation activity, conditioned by surface tension of solution and, thus, defined by the structure of hydrocarbon fragment of the reagent.INTRODUCTIONIt is believed that collecting ability and selectivity of collecting reagents is mainly governed by adsorption of a reagent at the solid–liquid interface. A few studies have shown that activity of collecting reagents at the gas–liquid interface may have deep influence on their collecting capacity and selectivity. Experimental researches have revealed correlation between surface pressure in a carboxylic acid film on liquid’s free surface and floatability of useful components (Kulkarni & Somasundaran, 1975; 1980; Quast, 2006). According to Quast (2006), it is not always that surface pressure of a reagent film influences collecting ability of carboxylic acid. For instance, pH range of adsorption of tetradecanoic acid on hematite does not coincide with pH range of high surface pressure. So, surface properties of this acid contribute little to flotation efficiency.The correlation between reagent film surface pressure and mineral floatability has been reveled for quartz and cationic reagents, too (Bleier, Goddard, & Kulkarni, 1977). Finch & Smith (1973) showed that combination of adsorption of ion–molecular amine complexes on mineral surface and high surface tension of “fresh bubbles” was favorable for flotation performance. The use of bubbles with reduced surface tension resulted in a decrease in quartz floatability."

Jan 1, 2016

The Production Profile Program is written for use on a Digital Model PDP 11/70 computer using a Fortran IV level G language. It may be run on any system which uses G level or an upward compatible version of Fortran IV language. Please note, however, that the Model PDP 11/70 for which the program was written is programed to read DEC026 type keypunching. If the user&apos;s computer is programed for another type of keypunching it may be necessary to re-keypunch the Production Profile Program. The Production Profile Program uses a fourteen card input. The data must be keypunched according to the layout described in detail in the multiple card layout forms (following). The output from this program must be printed on wide paper, as a full 120 columns are used. The samples of output at the back of this appendix have been reduced for inclusion in this report.

Jan 1, 1977

By Robert W. Schaut

The use of micropiles is increasing for new construction and to retrofit distressed foundations in expansive soils. Typical micropiles in expansive soils have a lower section where the micropile grout is embedded in direct contact with the soil, and an upper section that is cased with rigid PVC pipe or other material to reduce the friction between the micropile and the surrounding expansive soil. In the upper cased section, the micropile grout is in direct contact with the inside of the casing. During construction, grout can flow upward into the annular space between the soil and the outside of the casing as the grout is tremied into the micropile. Thus, various interfaces may exist in a typical micropile, including soil-to-grout, grout-to-PVC, and soil-to-PVC. As the surrounding soil heaves, shear stresses are mobilized along the interfaces. The frictional characteristics of the interfaces are design variables that must be evaluated. For this study, an experimental program was conducted to evaluate the shear strength of the three interfaces listed above. Conventional direct shear testing was performed at a commercial testing laboratory. In addition, specialized testing was performed at Colorado State University (CSU). For the CSU testing, an interface testing protocol was designed using a modified triaxial cell to allow evaluation of the interface characteristics between rigid PVC and cylindrical specimens of grout or clay soil. It is shown that the shear strength of the soil-to-PVC and grout-to-PVC interfaces are similar, both of which are significantly lower than the shear strength of the soil-to-grout interface. This indicates that the use of a PVC casing in the upper portion of a micropile has a positive effect in reducing friction and the shear stresses resulting from expansive soil.

Jan 1, 2011

By D. C. Fuller

CoaLiquid, Inc. (CLI) has been in the coal- oil-mixture (COM) business for over five (5) years. The initial pilot processing facility was replaced by a 2000 barrel per day commercial production facility in August of 1979. For over two (2) years CLI has been expanding its efforts and conducting large scale production and combustion demonstrations successfully in many locations across the United States. To facilitate the marketing effort, CLI has recently constructed a special trailer containing all equipment needed for a temporary COM retrofit. CoaLiquid has conducted commercial scale combustion demonstrations in the following types of combustion units: kilns, calciners, industrial boilers, blast furnaces and driers.

Jan 1, 1982

By Brenda Myers-Bohlke, Tor L. Brekke

INTRODUCTION In recent years several cities in the Eastern United States have constructed subway systems in deeply weathered igneous and metamorphic rocks. Portions of these transit tunnels and shafts have penetrated zones of saprolite. The purpose of this paper is to define saprolite and discuss saprolite behavior in terms of construction and design of tunnels and shafts. Saprolites are products of in situ weathering of rock, with properties intermediate between those of soil and rock. A well-developed weathering profile can be divided into zones of residual soil, saprolite, transition zone materials, weathered rock, and fresh rock. Saprolites are distinguished by a high degree of weathering and by retention of parent rock textures and discontinuities. These structures persist as relict features because of iso-volumetric weathering (Cleaves, 1974) and formation of intergranular bonds that give cohesion to the saprolitic material. As saprolite continues to weather, the bonds are broken, causing the saprolite to decompose and disintegrate into a true residual soil mass without relict structure. Saprolites may form from igneous, metamorphic or sedimentary rocks, but are most easily recognized when derived from igneous and metamorphic rocks because of their inherent structures. The physical characteristics and properties of residual material vary as a function of mineralogic composition, structure, and discontinuities of its parent rock.

Jan 1, 1985

By Christopher Mark

Knowledge of in situ stresses is fundamental to many studies in earth sciences, and coal mine ground control is no exception. During the past 20 years, it has become clear that horizontal stress is a critical factor affecting roof stability in underground coal mines. The theory of plate tectonics and the World Stress Map (WSM) project has been extremely helpful in explaining the sources and the orientations of the horizontal stresses observed underground. Recently, WSM geophysicists studying deep-seated stresses have developed a model of how stress magnitudes vary with depth in the crust. They have devoted relatively little attention to near-surface stresses, however. This paper explores the relationships between deep-seated and shallow in situ stresses in several of the world?s coalfields, using a data base of more than 350 stress measurements from underground coal mines. The analysis indicates that distinct regional trends exist, corresponding roughly to the regional stress fields identified by the WSM. The paper presents equations for estimating stress magnitudes that were developed by treating depth and elastic modulus as independent variables in regression analysis. The magnitude of the horizontal stress increases with depth, at rates that range from 0.8 to 2.0 times the vertical stress, just as the WSM ?critically stressed crust? model predicts. Overall, it seems that the stress regimes encountered in underground coal mines are closely linked to those that exist deep in the earth?s crust.

Jan 1, 2008

By Humberto Tronconi Coelho

The use of friction dampers are wide proposed for a variety of mechanical systems for which it is not possible to apply viscoelastic materials, fluid based dampers or others viscous dampers. An important example is the application of friction dampers in aircraft engines to reduce the blades vibration amplitudes. In most cases, friction dampers have been studied in a passive way, however, a significant improvement can be achieved by controlling the normal force in the contact region. The aim of this paper is to study four control strategies for friction dampers based on three different hysteresis cycles. The first control strategy maximizes the energy removal in each harmonic oscillation cycle, by calculating the optimum normal force based on the last displacement peak. The second control strategy combines the first one with the maximum energy removal strategy used in the smart spring devices. Finally, is presented the strategy which homogenously modulates the friction force. Numerical studies were performed with these four strategies defining the performance metrics. The best control strategy was applied experimentally. The experimental test rig was fully identified and its parameters were used for numerical simulations. The obtained results have shown the good performance for the friction damper and selected strategy, also, the agreement between numerical and experimental results.

Jul 31, 2018

During recent years there has been a marked increase in the use of explosives in Queensland coal mines. Delay detonators have been introduced and their use has extended with the wider application of mechanised methods of mining.The need for careful study of the characteristics of delay detonators is stressed so that the advantages of simultaneous firing, from the points of view of safety and efficiency, may be obtained. With their use new potential hazards are introduced. These hazardsare considered and means whereby the overall safety may be improved are discussed.The increase in the number of misfires since the introduction of delay detonators is shown and the examination of misfired detonators is described. Lessons to be learned! from these misfires are noted and details are given of the essential requirements for safe and efficient blasting using delay detonators.INTRonUCTIONOne of the aims of mechanization in coal mines is to reduce the physical effort applied to the winning of coal. Explosives play an important part in achieving this and, following the introduction of power borers for the drilling of shot-holes in Queensland coal mines, much of the arduous work associated with coal getting has been eased. During recent years there has been a marked increase in the consumption of explosives, as shown in Table 1, and it must be the aim of all to use these explosives safely and efficiently. That there are dangers associated with the use Of explosives cannot be denied. The shotfiring operation is fully covered by legislation and, being under the control of one man, shQuld be capable of being carried out with a high degree of safety. The main source of accident appears to be the failure to take proper cover and this has resulted in...

Jan 1, 1958

By Sanjiv Dhanjal

"Often mineralogy dictates the physical properties of a material rather than chemistry. This in turn affects how that material behaves in a process plant, and whether optimum conditions for refining one mineral are different to those for refining another. For example how does refining copper from chalcopyrite differ to refining copper from bornite?Minerals are naturally occurring inorganic solids that have a definite chemical composition and an ordered atomic (crystalline) structure. X-ray diffraction is a common and highly developed method to identify and quantify minerals. X-rays are fired onto a material and the mineral is identified by the angles where the diffracted X-rays are in phase.Most X-ray analyzers are laboratory based. A sample is prepared and analyzed by a detector that travels in an arc to collect the diffraction pattern. COSMA has a curved detector which picks up the complete x-ray pattern instantaneously. Therefore, material is collected and transported through the machine where is it is analyzed continuously.COSMA measures about 0.5 tons of material per day, while laboratory analyzers measure a few grams at a time. Real time data trends are produced allowing for improved process evaluation and automatic control. The COSMA on-line system has taken X-ray diffraction out of the laboratory into the field.There are a number of systems in operation in cement production. It is recognized that on-line mineral analysis has a role in many other processes. This paper presents the technology and invites further discussion should the technology be beneficial to members of the audience.INTRODUCTIONThis article describes COSMA, a system that provides direct and continuous on-line mineral analysis using X-ray diffraction in the field. While X-ray diffraction is a common technique used in mineral analysis, the time from sampling to analysis can be hours and plant operators typically do not get the data in time to control a process or respond to an upset. COSMA provides rapid measurement, analysis and feedback of data, in real time. This provides powerful information that can be used to optimize operation, thereby reducing costs and increasing quality."

Jan 1, 2009

By J. Richard Lucas

Today, the future of the coal industry is extremely bright because coal can be produced at a cost which makes it competitive with other energy sources. However, the industry has been forewarned that further cost reductions must be made if it expects to remain a serious contender in the growing energy market. Surface as well as underground operations must be improved. The very same elements which affected production a. few years ago still exist today and will continue to be present in the future. Improvement&apos;s in production mining equipment, mining methods, and auxiliary equipment have resulted in reduced costs over the past few years. Efforts must be continued toward further reducing costs in areas which have been improved previously, and new areas should be investigated for possible improvements. Therefore, new techniques must be developed which will enable the industry to augment its current efforts in reducing the cost of mining. The logical place to begin evaluating the factors affecting production and cost is in the immediate face area where a substantial part of the total cost of mining is incurred. The coal industry stands to gain much through the development of new techniques for analyzing the numerous variables affecting production and by establishing methods for eliminating or minimizing the adverse effect of those variables which can be controlled. Intuition and trial-and-error methods have been the standard means used to resolve many of the factors which influence production. As a result, many elements are overlooked or ignored because their effect on production is not pronounced and cannot be readily resolved. The need for a method of analyzing such factors was recognized by the Office of Coal Research. Therefore, in April 1962, under OCR sponsorship, a. research project was initiated at Virginia Polytechnic Institute (VPI). The objective of the project was to identify the factors which influence mining costs in the immediate production area, and to develop methods and techniques which will enable the coal operator to minimize production costs. The objective of the research at VPI has been successful, and techniques have been developed for establishing quantitative facts concerning the interrelationships of production activities.

Jan 1, 1965

By C. B. DUTTON, W. F. RITTMAN, E. W. Dean, M. S. HOWARD

NOMENCLATURE USED IN THIS REPORT. In this report the ending ene has been used throughout, except in the bibliography and in quotations from the writings of previous investigators, for all aromatic hydrocarbons, as, for instance, benzene, toluene, xylene. The ending ol, though largely used in technical description, is not correctly applicable to these hydrocarbons, and should be used to designate the impure mixtures of commerce, as distinguished from pure chemical compounds. PRESENT STATUS OF PETROLEUM-REFINING INDUSTRY. Although petroleum is widely distributed, being found in many parts of the world, and although information as to its occurrence and general characteristics seems to have existed from vcry early times, our knowledge of the chemical nature of this substance has been acquired largely within the past 40 years. Within this period a voluminous literature has accumulated, which records work as painstaking as has ever been undertaken in the whole field of chemistry, such as that of C. M. Warren, F. H. Storer, S. P. Sadtler, S. F. Peckham, and C. F. Mabery. Despite this fact, the commercial method of treating crude petroleum for the purpose of procuring marketable products is, in the main, essentially empirical. Much knowledge has been acquired as to methods of separating from crude petroleum such products as are desirable commercially, but little has been done to attain the maximum recovery of such products.

Jan 1, 1916