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By L. A. Puchkov

The paper presents the outline of the results in the algorithms and software of the microprocessor-based system for the powerful drugline bucket automatic motion, as well as the technological process control and functional diagnostics of the electrical equipment. The system is, aimed at the increasing both the draglines' working efficiency and the professional, competence of the operators. The excavator-dragline, equipped by the automatized operation, diagnostic and information processing system, possesses considerable technological: flexibility, which can widen therefore its field of application. The tasks of the dragline bucket motion optimal operation, programming of the excavation and overburden dumping processes, as well as the tasks of the control and the analysis of the technological parameters and the diagnostics of electrical equipment conditions, are defined in the paper. In our paper we present the results of these tasks being solved, providing the algorithms of the main mechanisms for the automatic operation for the swinging bucket controlled motion, the algorithms of the statistical analysis of the working efficiency parameters the algorithms of the diagnostics for electrical driving systems. The algorithms of the motion operation are constructed using the predicting dynamic models. The diagnostic algorithms at the normal working conditions form a number of algebraic invariants always equal to Ø with the accuracy up to when the electrical equipment is parametrically adequate. The algorithms of evaluating and analysis of the excavation efficiency make use of the direct measurement and analytical identification. The working condition and quality of the operation and control algorithms are investigated by simulation and natural testing. The results of the mathematical simulation of the bucket motion (with the 20 m3 capacity) of the excavator-dragline with the boom of 90 m in length are given in the paper.

Jan 1, 1992

By Ralph Loyd

One of the principal responsibilities of the California State Geologist is to provide local governments with maps and information regarding mineral resource occurrences within their jurisdiction. The primary objective of this effort is to furnish basic data that is essential in planning for and accommodating wise development of mineral deposits that are important to the economic well-being of the region, state, and nation. Local government agencies are required by law to incorporate the information provided by the State Geologist into their general plans and formulate mineral resource management policies that emphasize conservation and development of mineral deposits. The Mineral Land Classification program was initiated by the State Geologist in 1977 under authority of the California Surface Mining and Reclamation Act (SMARA). To date, about 33,000 square miles of land have been classified for mineral resource potential. Most of the mineral land mapping has been conducted in three principal areas: (1) metropolitan areas of the state where urban encroachment has greatly diminished available supplies of construction aggregate; (2) Sierra Nevada foothills, a region that is undergoing dramatic population increases; and (3) the Mojave Desert and Great Basin regions, where large Federal land withdrawals are pending that could preclude mining. Mineral land classification studies address the overall mineral potential of a region through the identification of local and regional geologic factors that control or influence the formation of mineral deposits. These studies are field-intensive surveys that enable project geologists to gain first-hand knowledge about the nature and distribution of mineral deposits in a given area and portray that information accurately in map form. This paper summarizes the progress made in the Mineral Land Classification program in the metropolitan, Sierra Nevada foothills, and the Mojave Desert/Great Basin regions of California. Selected projects from each area are discussed in detail.

Jan 1, 1995

By Dale R. Ralston, Roy E. Williams, Gerry V. Winter, George L. Bloomsburg

The purpose of this section is to demonstrate the development of a method that we believe can be used for simulating and predicting mine water inflow. It will also show how important it is for personnel who model mine water inflow to have considerable experience with this subject, and with the conversion of hydrogeologic frameworks to conceptual models. Several of the models described previously are said to be three dimensional. However, closer examination reveals that there is considerable limitation in the variation possible in the third dimension. A true three-dimensional analysis would require a very large program. Therefore, it seems more reasonable to develop a procedure by which information from a two-dimensional model can be used for analysis of a three-dimensional problem. For a vertical mine shaft this is relatively easy because most two-dimensional models have an option for axisymmetric flow. If it can be assumed that axisymmetry exists about the centerline of the shaft it can be modeled easily as has been illustrated previously. For a horizontal drift or tunnel the analysis is not nearly as straightforward. However, the flow can be divided into two parts as indicated in Fig. 59. Part 1 considers the flow into the side of the drift while part 2 considers the flow into the end of the drift. To calculate the flow rate into the entire drift from the unsteady flow into a unit length the instantaneous flow per unit length may be integrated over the total length of the shaft. This procedure is shown in Fig. 60. The radial flow through any incremental length of the shaft is q. The total flow rate, Q, into the drift at any particular time is given by: The discharge q is a function of the time during which a particular segment has been draining that is dependent on the location x. In other words, a location at x = 0 has been draining during the entire time of expansion while a segment at x = L has only started to drain. Therefore, the time of draining at any point, x, is given by: [ ] where t' is the time over which the mine has been expanded. To determine the relationship between q and t it is necessary to refer to Polubarinova- Kochina (1962, pp. 566-569) and the equation given for the unsteady flow problem. This is: [ ] where q is the steady flow, q,, q, are the coefficients, and t is the time since drainage began. The expressions for q0, q1, and q2 are given as:

Jan 1, 1986

By B. H. Kaye

Particle-size Distribution Specifications for Particulates. Feed to and finished products from size-reduction operations are defined in terms of the particulate sizes involved. It is also well to know whether the ultimate individual particle is being measured, or, if any aggregation or agglomeration of particles exists, whether this has been created by the size-reduction operation. The most complete description of a powder is given by its particle¬size distribution. This can be plotted in terms of cumulative percent oversize or undersize in relation to the diameters of particles, or it can be plotted as a distribution of the amounts present in each unit of diameter against the several diameters. It is common to employ a weight basis for percentage, but there are some data in the literature where frequency, or number of particles, is used. The basis of percent¬age, whether weight, frequency, or some less commonly used factor, should be specified, as also should be stated the diameter, its units, and preferably whether determined by sieve, settling velocity, or other¬wise. Fig. I presents two sets of distributions-ore cumulative and the other in unit intervals. The slopes of the 5-µ intervals of the cumulative curves are converted to percent per micron and plotted as a block, or histogram, from which smooth curves are derived. Powder A has a narrower, or tighter, size range for the bulk of its weight than powder B. Both materials have the same weights below and above the size marked by the arrow. Simpler treatments of distribution are possible. In some cases the significant value is the top size. Since the 100% point is dubious, some amount, as 95 or 98%, so specified, can be called top size. In other cases the percent on some sieve helps define coarseness. Merely stating that all, or all but a small percentage, passes a given sieve is inadequate for defining the true fineness or a material. Complete parti¬cle-size analysis to show the distribution is essential for most compari¬sons and calculations. Particle-Size Equations. A number of equations have been pro¬posed to correlate the quantity of a particulate material with its parti¬cle size to obtain a distribution relationship. 's 19 In the literature it is often assumed that a powder must follow some distribution, such as the Rosin-Rammler-Bennett:20, 21

Jan 1, 1985

By J. B. Ackerman, C. S. Bucans

The Sunshine Mining Co. has recently started up its new silver refinery in Kellogg, ID. The new plant recovers silver anc copper values from a high grade tetrahedrite concentrate using hydro- metallurgical processes. The plant and process are both new and have gone through the initial startup phase during the first six months of 1985. The full scale plant was developed from laboratory test work. While the metallurgy of the process worked as expected, the material handling problems were difficult to over-come. As might be expected, those parts of the plant that represented available technology started up easily, while the parts that represented new technology presented the most difficulty. Topics covered in this paper include: 1) insufficient type and amount of agitation in the leach vessels, 2) discharge of a non- homogeneous slurry from the leach vessels, and 3) problems associated with very low flow rates in slurry lines.

Jan 1, 1987

By Peter E. Hart

The search for mineral deposits is a difficult high-risk enterprise whose likelihood of success is influenced by a great many factors. Among the most important of these factors are the knowledge and judgment brought to bear on an exploration problem. If, for example, a panel of expert highly experienced geologists could be convened to examine every prospect, it is at least plausible that fewer deposits would be overlooked in the exploration process. Unfortunately, whether a project is undertaken by a private company or a government agency, it is not usually feasible to convene such a panel. Our purpose in this chapter is to describe an experimental system of computer programs called PROSPECTOR that is intended ultimately to provide expert consultation on problems of mineral exploration and resource evaluation. Ideally, PROSPECTOR would serve as a surrogate for a panel of expert economic geologists. However, because the cost of computation is very low and is projected to drop by a factor of about 100 over the next two decades, systems like PROSPECTOR could be made available to the exploration enterprise at large. When consulting about a prospect, the PROSPECTOR system first gives the field geologist an opportunity to tell the program about the most significant features of the site: the major rock types, minerals, and alteration products. The system then compares these observations with a number of stored models of various types of ore deposits and forms alternative hypotheses about the types of deposits that might be present. The system next engages the geologist in a dialogue in order to obtain additional data that would be useful in resolving the multiple hypotheses. The geologist can interrupt the system at any time to obtain clarifications of questions, volunteer additional data, request the reason a particular question has been asked, or obtain a general summary of the state of the consultation process.

Jan 1, 1979

By M. Poulton

Backpropagation, learning vector quantization, counterpropagation, functional link, probabilistic, and. self -organizing map are among the most popular neural network classification paradigms. Each paradigm finds a unique set of weights that will map the input pixels into their respective output classes. The usefulness of each network depends on its overall accuracy, ease of use, speed and scaling. The fastest and most accurate networks in this study were the functional link and counterpropagation. These networks, however, do not scale well to large input vectors or large training sets. A better choice is the LVQ network which achieves high accuracy, is fast, requires a minimum number of input parameters and presents fewer scaling problems.

Jan 1, 1992

By John L. Bolles

The mineral processing engineer must have some knowledge of mineral identification, and the greater his knowledge in this field, the greater will be his potential to do his own specialty well. Most metal-bearing ores and industrial minerals require processing of some kind to produce a salable product or a material suitable for further processing. The types of treatment are many, but each one is aimed at separating a mineral or family of minerals from others. Obviously, then, it is basic to all mineral processing to identify the minerals present in the raw material and in intermediate and final products resulting from processing. Very often the mineral processing engineer will enter planning while exploration of a mineral prospect is going on. He will examine hand specimens, drill cores and cuttings, bulk samples, and materials in place. He must identify the valuable minerals, their occurrence and associations with other minerals, and the identity of diluents or host rock. An exact and detailed knowledge of the raw material will usually suggest the treatment processes that should be investigated in the development of the most suitable scheme for that particular raw material in that particular location. Physical properties of a mineral often lead directly to a process for separating that mineral from others. Some well-known examples of these are: magnetic separations for such minerals as magnetite, rutile, ilmenite; gravity separations for gold, silver, galena. cassiterite; flotation separation for most sulfides; distillation of mercury from cinnabar; and selective dissolution in specific solvents such as halite or sylvite in water, gold and silver in cyanide solutions, copper oxides, carbonates, sulfates and silicates in dilute sulfuric acid. These processes and many others are described in detail elsewhere in the Hand¬book and so it is not appropriate to give details here, except to emphasize that processing is aided greatly by complete mineral identi¬fication. Developing a treatment scheme for a new mineral discovery is an exciting assignment fag the mineral processing engineer, but much more of the usual work relates to quality control in existing plants. Here too, mineral identification is important. Some processing is aimed toward producing an end product which will meet exacting specifica¬tions regarding purity or allowable diluents. In this situation it is vital that contaminants be identified so that the process can be adjusted

Jan 1, 1985

By J. Mark Richardson, Mary S. Sredanovic

The use of computerized steady-state process design balance systems has reduced engineering man-hours by as much as 80 to 1 over conventional manual balance calculations. The popularity and widespread use of such systems by the minerals industry increased dramatically in recent years, but these systems were mainly available for use on large main frame computers and lacked graphic capability. A considerable amount of engineering manpower was required to "conceptualize" a process flowsheet. After sketching the flowsheet layout, the engineer was still faced in most cases with a time-consuming reduction of his graphic concept of the problem to numerical data required by the balance program. Furthermore, output from these early systems was usually in tabular numeric form. The computer results then were transferred manually to a pictorial representation of the process. A new process design balance system has been developed which runs on a popular and inexpensive personal computer. This system combines modern Computer Aided Design (CAD) principles and the graphics capabilities of the personal computer to allow the process engineer to define a flowsheet problem while creating a process flow diagram. The system provides balance results in both pictorial and tabular form. Past, present, and potential applications of the system are discussed, and an analysis of the cost benefits derived from its use are provided.

Jan 1, 1985

By D. F. Symonds

INTRODUCTION Dense medium processes have been used to separate coal and ores for over a hundred years. In fact Sir Henry Bessemer first patented a process in 1858. In recent years, their importance relative to other gravity dependent processes has increased. This is particularly true in the coal industry where over 60% of all preparation plants operating in 1984 in North America (1) contained either dense medium vessel or cyclone circuits. In addition, the stringent product quality demands of the consumer, together with increases in mining costs, dictate that the cleaning circuits be both predictable and efficient. Dense medium systems are the most predictable and efficient of all gravity- dependent processes. The majority of the text of this chapter will be concerned with dense medium applications as they relate to the coal industry. However, the techniques and calculation procedures can be applied, in general, to all non-coal minerals (such as diamonds, marginal iron and lead-zinc ores and gravel) which take advantage of a difference in specific gravity between the saleable product and the reject. The object in dense medium cleaning is to produce a liquid whose effective specific gravity is between that of the concentrate and the reject. In which case the lighter product will float to the surface and the heavier product will sink to the bottom. Unfortunately, this simple process becomes complicated by the following practical necessities: (a) collecting and removing the float and sink products from the medium without disturbing the free settling effects; (b) maintaining and controlling the specific gravity of the medium; (c) separating and reclaiming the medium once the products have left the separating vessel; and (d) separating finer sized particles which take longer to fall through the dense, and often viscous, medium. As a result of the last issue (item d) two main types of dense medium separators have evolved: dense medium vessels and dense medium cyclones. Dense medium vessels are essentially large baths through which the dense medium flows at a relatively slow velocity. The lighter products float to the surface and are carried out of the vessel by the medium flow. The heavier products sink to the bottom of the vessel and are physically transported out either by means of a conveyor (usually a chain conveyor) or a rotating, lifting arrangement (Figure 1). They generally

Jan 1, 1986

By H. Beecher (Original by) Charmbury

Water is a most remarkable substance, essential for life of all kinds. As well as needing water to survive, man has always used it for agriculture, transportation, recreation, and many other things. When our country was young and inhabited by few people, the streams, rivers, and lakes were able to provide all the clean water needed by man and take away all the wastes created. However, with our growing population and an ever-increasing demand for goods and services, the public, industry, and government at all levels have become acutely aware of the need to manage the nation's water resources more efficiently. Abundant energy from many sources has helped this nation to become the greatest industrial nation in the world. Coal has contributed a major portion of this energy, generating electricity, running railroads, and maintaining national security during wartime. The result has been the highest standard of living in the world and a time of widespread economic prosperity. The use of water in coal mining is somewhat different from its use in most industries. With the exception of water used in cleaning plants, for underground dust control, and for fire protection, most of the water en- countered in coal mining operations serves no useful purpose. In other words, it is an undesirable element and must be removed, otherwise it will interfere with operations, cause potential water quality problems, and may even stop operations by flooding. In the past, removing water from working areas of most mines was usually a fairly simple matter. Pumps with piping were installed at sumps or low spots in the mine and the water was pumped to the surface or to drainage control facilities constructed for the operation. Ditches were often used to collect and drain the water by gravity to the outside or to main sumps for pump discharge. In either case, the water was allowed to flow into the nearest stream or river. The concept of "water is water' was generally accepted without too much concern for what was in the water since low-cost products and services, rather than clean water, were the public demand.

Jan 1, 1981

By David R. Klug, Chris Gause, Troy L. Page

The Inter-Island Tunnel is one of two undersea tunnels which are part of the Boston Harbor Clean-Up Program. The tunnel is 7.7 km (25,160 ft) long, bored to a 4.3 m (14 ft) diameter in the Cambridge Argillite Formation and was finished to a 3.5 m (11.5 ft) diameter final concrete lining. The owner is the Massachusetts Water Resources Authority (MWRA) who is a regional authority responsible for overall design and construction. The tunnel's primary purpose is the transport of untreated effluent from Nut Island facility in Quincy, MA to the new treatment plant at Deer Island. Two sludge lines are installed for the transport of sludge from Deer Island to Nut Island. During construction the contractor encountered fault zones, fractured strata, and soft ground tunnel sections which liberated more ground water than was originally anticipated by the project designer. Ground water was controlled during mining and the placing of the final lining. The final lining of cast-in-place concrete had to be backfill grouted to cut off water inflows and provide contact for equal tunnel loading which is critical in long-term design. This paper deals with an engineered backfill grouting system which was the first of its type to be used in North America. It discusses the geological conditions encountered, the design criteria used in the evaluation process, and an indepth review of the various system components. It demonstrates how contractors can use knowledgeable and professional industry suppliers to solve difficult construction problems.

Jan 1, 1999

By V. B. Achanti, A. W. Khair

Developing a laboratory procedure for the determination of coal-seam compressive strength has been a subject of discussion for many decades, and the reliability of laboratory determinations is often the subject of debate. A coal seam’s characteristics, the method of sample collection, the specimen preparation method and the testing procedure can often result in drastic variations in the test results. In this paper, the development of a laboratory testing procedure for the determination of coal-seam compressive strength is presented. Two samples that were collected from different coal seams were tested in this study. First, the inherent characteristics, i.e., coal structure. Hardgrove grindability index (HGI), Slake durability index, proximate analysis and mechanical properties (Young's modules and Poisson's ratio), of each coal were determined. The results were used to categorize the coal scams in terms of the characteristics liable to produce variable strength data in typical laboratory tests. Second, two commonly used laboratory specimen shapes, cylindrical and cubical, were tested to determine which shape produced the most reproducible strength values. Third, four loading rates within the static testing range, i.e., 0.007, 0.07, 0.34 and 0.7 MPa/s (1.0, 10, 50 and 100 psi/sec), were used to determine the ideal loading rate. Finally, the number of test samples required to produce strength data within the acceptable standard deviation, considering coal seam characteristics, were established. Background Laboratory testing of coal specimens for the determination of seam compressive strength has been a subject of discussion since the early 1900s. Many researchers have tested coal specimens to estimate coal-seam compressive strength for use in pillar design to insure the safe operation of [ ] mines (Unrug et al., 1986; and Hirt et al.. 1992). Yet, there is a lack of a universal procedure, and, no matter which approach is used, it becomes the subject of intensive debate. A great deal of work has been performed on the subject, and there is much information available in the literature. Some of this work concerns quantifying the influence of specimen shape and size on compressive strength (Bieniawski. 1968: Barron et al.. 1992: Khair and Xu 1994; and Khair 1994). As indicted in the literature, coal is a heterogeneous material, consisting of discontinuities such as cleats and bedding planes, which are likely to produce variable strength results (Holland, 1964; Unrug et al., 1986). Some of the prominent issues that influence the determination of coal-seam compressive strength in the laboratory are: •the collection of a representative sample from a coal seam; •the geometry, i.e., shape and size of the specimens to be prepared and tested: •the loading rate at which the specimens are to be tested:

Jan 1, 1997

By C. P. Shen, H. C. Tsai, Bennie Chu, Y. S. Hsieh

The Pinglin tunnels are situated within the fold-and-thrust belt structural region in Taiwan, due to continent-arc collision and plate tectonic setting. The pilot tunnel TBM (§=4.8m) became stuck ten times with the standstills to date. The westbound main tunnel TBM (§=11.74m) was buried in a collapsing calamity. The main tunnel TBM shall identify and overcome the adverse geology with high volume of ground water ingress itself. This paper presents our experience and methodology through the adverse geology with Pinglin large TBM.

Jan 1, 1999

By Stephen Stone, Kerby Dobbs, G. Richard Whittecar, W. Lee Daniels, Zach Agioutantis, Tess Thompson

A common result of Environmental Impact Assessments associated with mining projects is the construction of new wetlands in areas disturbed by mining operations. Where appropriate, this mitigation may be considered an integral part of the mine reclamation process under the principles of sustainable development in the minerals industry. Wetbud is a new tool for estimating wetland water budgets using available weather data and site-specific topographic, soil and geohydrologic data, coupled with mass balance mathematics. Wetbud is primarily intended as a planning tool for use in the design of created wetlands, but it can also be applied to native wetlands or wetland restoration sites where the required input parameters can be specified. Wetbud can be run in its basic form where wetland topography, soil parameters and groundwater flux are simplified, or in the advanced form, where these parameters are included in a more complex approach via integration of the MODFLOW package, a free 3D program that was developed by the United States Geological Survey. Both versions can also include overbank flow hydrology sources and the advanced form can also model sloping and irregular topography. The program downloads weather data from the nearest applicable station and selects appropriate wet-normal-dry (W-N-D) years following a modest user data clean-up step. Wetbud also has the ability to utilize existing short-term (e.g. 6 to 9 months) groundwater data from an up-gradient well to simulate longer-term groundwater level inputs for the selected W-N-D years. In addition, Wetbud features a “Wizard” version that comes pre-loaded with 14 pre-selected weather data sets for all areas of Virginia that can develop a simple monthly water budget in less than 15 minutes – a feature that could be expanded anywhere geographically with historic weather data.

Jan 1, 2017

By John Ralston, Rossen Sedev, Nicola Richards, Quinn Anthony, Geoffrey Reynolds

Derivatised 2,4-diketopyrimidine groups have been anchored to planar gold surfaces as self¬-assembled monolayers (SAMs) for chemical and photochemical studies. Three derivatives, 5-methyluracil (thymine), 5-trifluoromethyluracil and 5-nitrouracil, were chosen for the specific moiety present at position C-5, which can exert strong or weak inductive effects on the adjacent aromatic ring. The measured acidity constants decrease from 5-methyluracil to 5-nitrouracil as the inductive properties of the group at C-5 position increase. When grafted to the surface the acidity constants increase, albeit still adhering to the expected inductive trend. The functionality also exerts an influence on the surface wetting properties. Surface wettabilities indicate that the orientation of the pyrimidine groups at the surface occurs so that the C-5 position has a direct effect upon the surface chemistry. Upon dimerisation the surface contact angles increase signifi¬cantly. At pH 11 the contact angle changes reflect that the dimer has a higher pKa than the monomer. The monomer surface is deprotonated at this pH while the dimer surface is partially deprotonated, leading to changes in contact angle of up to 22 degrees. Large changes in contact angle were observed for 5-nitrouracil which were independent of surface charge and were appar¬ently due to conformational changes alone. Electrowetting of three fluoropolymer surfaces by electrolyte solutions was studied with the sessile drop method. The electrowetting curve (contact angle/potential) is analogous to the elec¬trocapillary curve (surface tension/potential) and may be described by a combination of the Young and Lippmann equations. We demonstrate that for some specific surfaces a systematic deviation occurs at positive potentials. This departure is attributed to double layer effects, namely the adsorption of hydroxide and halide anions. pH, ionic strength and polymer composi¬tion can all influence electrowetting behaviour.

Jan 1, 2003

By Jun Han

Coal has been mined in the Kailuan mining area for more than 130 years. The remaining reserves consist of, in large part, coals that would have been considered economically unminable or technically not feasible by the previous generations. Some of the current operations have to resort to overmining because the lower seams had been extracted in the past. This paper deals with the feasibility and proper layout of mining roadways of overmining carried out in the No. 5 seam of Qianjiaying coal mine of Kailuan mining area using numerical and physical simulation. FLAC2D was used to investigate the characteristics of stress and displacement in the overburden after extraction of the lower seams. It also analyzed the proper layouts of gateroads in the upper seams, i.e. locating them in the stress-relief zone of the gob so that their stability can be easily maintained. In addition, a two-dimensional physical model was constructed for investigation of damages to the upper seams due to mining of the lower seams. Finally, based on the results of investigations, proper gateroads layout was designed and successful extraction was implemented for panel 1357 in the No.5 seam.

Jan 1, 2009

By R. Allan Wallis

In the past mining engineers have tended to rely heavily on the advice of fan manufacturers in relation to fan equipment issues. A more adequate approach was advocated in a paper [ Wallis, 1965 ] submitted to the Eighth Commonwealth Mining and Metallurgical Congress held at Surfers Paradise, Australia during 1965. At that time Mount Isa Mine were in the process of installing 3 large 6096mm (20ft) diameter vertical axial flow surface fans of an advanced type [ Mathews et al, 1967 ]. The preliminary feasibility studies prior to preparing the detailed job specification for this project were extremely thorough with the result that it was possible to include detailed information and instructions in the document, ensuring the procurement of equipment that was satisfactory in all respects. Full advantage was taken of expert services provided by external organizations during the large coordinated multi-disciplinary exercise. My continuing activity and development in relation to the technology of axial flow fans is now at a stage where all known design and performance data are accessible through CAD programs [ Wallis and Kipp, 1987 ]. The extensive calculations that were necessary in 1983 can now be carried out in a mere fraction of the time, and with complete confidence. Model testing in order to validate the fan and duct design proposals is, in my view, no longer essential. The first of the computer programs enables a mine ventilation engineer to study a large number of alternative axial fan arrangements for comparison with the centrifugal alternative. By entering the volume flow rate, fan pressure and air density, he can then with ease, and rapidly, investigate the effect of various blading arrangements, downstream evasee area ratios, and hub ratios, on fan diameter and speed, with their related attainable fan efficiencies. This procedure had its origin back in the 60s when I was advising mining companies on new fan equipment. At that time such an investigation was quite lengthy and lacked the precision and completeness that is now available within the present programs. To obtain the major benefit from these outputs, it is most important not to be disconcerted by the three very important nondimensional parameters, namely, the tip flow coefficient (LAMt), the fan pressure coefficient (Kt or Kit), and the swirl coefficient (Es and/or Ep) as these are important when assessing the various design proposals. When seeking an understanding of the role and importance of each of these variables, ample help is provided in the user manual; the design recommendations are summarized in the help screens which are readily accessible within the design programs.

Jan 1, 1989

In spite of our deep conviction that it would be wrong for the United States to enter World War II, when, after Pearl Harbor, we were actually in it, I felt that I must do all I could to help. The country had been so good to me that I could not decently stay on the sidelines. My first thought was that I might help with supply and administration in the Air Force, as in World War I. So on the evening of Pearl Harbor I wired the chief of our Air Force in Washington saying that I had been on Gen. William Mitchell's staff in World War I and was offering my services again. I received a noncommital answer, but after a couple of weeks was told to take my physical examination. I passed it, but nothing further happened. After helping to make plans for the wartime operations of Summit King and Desert Silver, Dorothy and I went to New York to spend Christmas with Molly and Peter, both of whom were in college in the East. I had to complete a report on the Argonaut mine in California first, though the war made my recommendations of dubious validity. Before Christmas I received wires from Temple Bridgeman, Phil Wilson, and other friends who had taken positions with government agencies responsible for securing mineral products needed for war use. They urged me to join them. It was evidently a case of not whether but how I could be most useful. After six uncertain days with the family in New York I took the night train to Washington on the 28th of December. I had a hectic day there. First I saw Arthur Bunker and Phil Wilson at what became the Aluminum and Magnesium Division of the War Production Board. Their office was in an old converted barracks. They asked me to examine magnesium deposits in Nevada at once, and then to look at other magnesium and aluminum properties. After leaving

Jan 1, 1976

By Scott G. Britton

The first section of this text delves into construction engineering techniques for successfully completing necessary underground production support projects. I will discuss alternative design concepts, installation practices, materials and material costs, completion time, and necessary labor for individual projects. The emphasis of this section is on describing each project thoroughly and providing a practical guide for the supervisor or engineer. There are four main construction categories for typical underground mining projects. These are: 1) Transportation of men and supply materials. This refers to track and wire installation and roadbed grading and ballasting. 2) Ventilation, composed of overcasts, man doors, regulators, and stoppings. 3) Drainage, including sumps, pumping stations, drainage networks, pumps, and face drainage. 4) Haulage of coal and rock from the face to the outside. The focus here is in the installation of belt lines, belt drives, transfer points, and vibrating bins/feeders. The first section shall fully discuss these four categories in regard to the construction engineer or supervisor designing, building, or improving a system. In addition, special projects such as surge bins, rotary dumps, and underground offices not classified under these categories will be discussed. For manageable purposes, I have limited the installation discussions to one or two approaches I feel have merit. The variation of installations in coal mining is endless, each with its own advantages and disadvantages. Therefore, the reader should not dismiss or restrict his thinking to only the approaches in the text. It serves as a guide only.

Jan 1, 1983