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By V. J. Sikora, T. S. Hutchinson

This paper presents a method for making a water-rlrive ana1gsis without prior knowledge of aquifer geometry and uniformity using a standard desk calculator. Although it is necessary to know the initial oil in place to use this method, this is a minor limitation to the scope of (he method since in most reservoirs it is possible to obtain reasonably accurate volumetric oil-in-place estimates. An equation is developed which relates pressure at the water-oil contact to the water influx rate as a function of time by a factor called the resistance function. The resistance function introduces the composite effect of the aquifer geometry and flow resistance disrribution. It is pointed out that the characteristic shape of this function makes it possible to start with on approximation of the function and successively improve the approximation until the correct resistance function curve is obtained. In this fashion water-drive estimates can be made without the limitation of assuming simplifed aquifer shapes and flow distributions. This is the novel feature of this development. Methods are given for extrapolating the final curve to calculate future aquifer behavior. Equations are developed for adjusting the pressures and water influx rates where it appears that possible errors in these quantities make it difficult or impossible to obtain a useuble resistance function curve without this adjustment. Application of the pressure build-up analysis techiiique to estimate. some of the aquifer properties is also presented INTRODUCTION A great many oil pools are the result of oil accumulation in some type of trap in an otherwise large and continuous porous stratum. The void space of this stratum outside of the oil pool itself is filled with water or brine. In analyzing performance of the oil pool surrounded by this water aquifer, it is quite necessary. in most cases, to include behavior of the water. When the pressure at any point in a fluid system is lowered, such as by opening a well in an oil sand, fluids in the immediate neighborhood of this point will begin flowing towards this lower pressure sink. As pressure in this area drops due to flow towards the sink, fluids from farther out will start to flow towards the lower pressure. As more and more fluid is removed from the system, the distance from the sink or well within which flow is occurring will continually increase; that is, thc region of disturbance will grow. If some rigid boundary such as a fault is reached by the disturbance, this area will cease to grow; but if some movable boundary is reached, such as a water-oil contact, the area will grow on out into the water, although rate of growth may and almost always does change. The relation between amount of pressure drop and amount of fluid flowing at any point and at any time in an aquifer depends on such factors as compressibility and viscosity of the fluids, the porosity and permeability of the rock, geometry of the whole system and withdrawal rate or pressure drop. With these factors known, it is theoretically possible to calculate the pressure-flow behavior of the system, However, in practice true solutions to the problem are next to impossible due to complexity of reservoir systems. A number of approximate methods of solution have been developed based on various simplifying assumptions. One frequent assumption is that the water-oil contact can be located and equations defining oil reservoir and aquifer solved separately by assigning values to various parameters so as to match past pressure and production history. Usually the properties of the aquifer are not known, since few, if any, wells are drilled through the aquifer; but the water influx and the pressure at the reservoir boundary are known over some time. If it can now be assumed that the aquifer is circular, pie-shaped, or linear, and that it has uniform properties, it is possible to fit a theoretical dimensionless curve to the past aquifer performance history and therefore calculate future water drive. These theoretical curves are available in the literature,1,2,3 Of course, the assumption of uniform aquifer properties is almost always somewhat in error. Fortunately, however, moderate variations from the average have little effect on behavior of the system; and, hence, the best fit of a theoretical curve is frequently satisfactory. In other cases variations in aquifer properties and geometry are large enough that none of the available theoretical curves will give an acceptable fit of the data. In these cases, methods of fitting the data with various electrical analyzers have been developed.1,2' It is the purpose of this paper to present an approach

By F. M. Morris

A large reserve of thick coal in southwest Virginia was developed by Clinch-field Coal Co. in 1957-1958 to produce a nominal rate of 1500 tph raw coal. Operation features coal cleaning in transit. Refuse removed averages 35 pct. Evolution of plant from initial conception to completion is discussed, selection of means applied is explained, and performance to date us design expectation is described. The long-range plan calls for ultimate handling capacity of 40,000 tpd raw coal with anticipated clean coal capacity of 26,000 tpd on a three-shift basis. From a materials handling viewpoint, the Moss No. 3 operation is principally of interest as an ensemble. Generally speaking, it uses time-tested equipment and ideas but some of these are employed on a scale that may be new in the industry. At present about 20,000 tpd of raw coal are being handled. This is expected to increase to 40,000 tpd as soon as business conditions justify it. The purpose of this paper is to discuss the evolution of the plant as to materials handling practices, to describe briefly the equipment and methods used, and to comment on performance in certain areas. The subject divides itself naturally into four phases: 1) operations at the mines, 2) transportation from mines to plant, 3) raw coal handling into the plant, and 4) transportation of refuse away from the plant. OPERATIONS AT THE MINES The coal reserves for Moss 3 are in southwest Virginia where Dickenson, Russell, and Buchanan Counties come together. This area contains about 15 square miles and over 100,000,000 tons of coal. Here the No. 4 (Tiller) and No. 5 (Jawbone) seams of the Norton Formation lie so closely together that for practical purposes, they constitute one seam of coal. This seam, which is called the Thick Tiller, varies from 10 to 18 ft in thickness and underlies Sandy Ridge, a mountain cresting between 2400 and 3300 ft above sea-level. At 18-ft seam height (which is considered to be the maximum practical mining height) the parting between seams will be about 3 1/2 ft thick and each bench of coal will be about 7 ft thick. Depending on the amount of impurities in the seams Drover. total reject in this height coal may approximate 50 pet by wt. It will average about 35 pet for the property as a whole. The first move in developing this resource was made in 1953 when contour maps of several square miles around Duty, Va., including all the known outcrop, were made by photogrammetry. At this time, it was felt the prospective operation would be served by the Clinchfield Railroad and a photogrammetric route survey was made by this railroad from Haysi to Duty. Study of the resulting maps indicated only one site—adversely owned—which might accommodate the size washing plant to be erected. Water resources of a dependable nature seemed nonexistent. In 1954 bulk washability tests were made on the Tiller Bench at the Moss No. 1 preparation plant. The tests indicated this portion of the seam, mined separately, would wash to 4 pet ash with good recovery. Also in 1954, development of Moss No. 2, south of Sandy Ridge, was begun. This mine is in the Tiller Seam where it is about 100 ft below the Jawbone Seam. The reasons for developing a mine in the normal Tiller Seam before tackling the Thick Tiller seemed compelling: Railroad service could be established quickly, communications were better (though not good!), more was known of the seam (it had been mined in the years 1911 to 19241, and there was no essential property to be acquired. After some legal skirmishing, the Norfolk & Western Railroad was granted the right to serve the new mine. Three decades earlier the old mine had been served by the Clinchfield Railroad. The event which triggered active development of Moss 3 was the Appalachian Power Co.'s decision in 1956 to build a 450,000-kva power plant on Clinch River at Carbo. This solved the problem of marketing the steam coal which inevitably must be a product of a mine in the Thick Tiller. Management promptly decided to build the preparation plant at Carbo where an excellent site was owned; where railroad service existed; where telephone service could be obtained; and where roads, bridges, and water supply were tolerable.

Jan 1, 1961

By J. L. LeBlanc, R. L. Lewis

This study presents an analysis of annular backpressure variations associated with controlled gas kicks and their pronounced effect on casing .strings and exposed under lying formations. A mathematical model describing the volumetric behavior of an extraneous gas as it is transported from reservoir to .surface conditions under changing temperatures and pressures has been programmed in a Kingston FORTRAN II language for digital computer analysis. The gases under investigation typify Gulf Coast reservoir gases within a 0.6 to 0.7 .specific gravity range. The program output has been substantiated by actual field cases. of gas kicks encountered in Gulf Coart we1l.s. The development of empirical equations for calculating suitable gamy deviation factors for unique temperatures and pressures was incorporated in the program to provide realistic solution.. An output listing of annular backpressures and corresponding equivalent fluid densities resulting at a predetermined critical depth (casing setting depth) and total depth for selected .stages of circulation is provided in a chronological .sequence. Additional information including reservoir pressure and temperature, kill rnrid density, produced gas or surface volume of the expanded gas intro vion, drill pipe and annular volumes can he obtained from the model. This paper illustrates that a precise knowledge of the volumetric behavior of extraneous gases in annular flow and its effect on equivalent fluid densities at a critical depth is significant and should receive .serious consideration in controlling threatened blowouts and in the design of drilling programs. Surface pressures in excess of formation limitations are a threat to zones of lost circula/ion and are potentially injurious to productive intervals. A knowledge of annular backpressure and equivalent fluid density profiles for probable gas kicks aids in a technological accomplishment of drilling programs and provides a .sale tolerance in the event a threatened blowout is encountered. Introduction Drilling operations are frequently interrupted when the drill bit penetrates permeable gas sands with reservoir CtfuJ manuscript was received in Society of Petroleum Engineers ofice Am. 1 1967. Revised manuscript received JuIy 7. 1968. Paper (SPE 1860) kae presented at SPE 42nd Annual Fall Meeting held in Houston. Tex., Oct 1-4, 1967. @ Copyright 1968 American Institute of Mining, Metallurgical, and Petroleum Engineem, Inc. pressures greater than that exerted by the drilling fluid. The differential pressures resulting permit an extraneous influx of gas into the wellbore. A suspension in drilling progress is necessary to restore fluid equilibrium throughout the system. Whether formation gas kicks originate unintentionally or by design, the prospect of a threatened or actual blowout exists and a method assuring a safe and effective well control procedure must be observed. A significant contribution to well control technology was advanced by Records et a1.l in 1962. Using the concept of transmitting a constant equivalent formation pressure at the point of intrusion, Records et al. introduced a calculation technique providing the annular backpressures encountered in a well control environment as a func tion of the volumetric behavior of a 0.6 specific gravity natural gas. In essence, the procedure outlined an annular backpressure schedule in terms of fluid volume circulated at different stages of a well control operation. A number of other publications2-' proposing various techniques for controlling gas intrusions in a wellbore achieve pressure control essentially through maintenance of a constant bottom-hole pressure by surface choke adjustments. The subsequent pressure effects induced in the annulus unfortunately receive little emphasis. Due to the tedious and repetitive nature of annular backpressure computations, a theoretical solution by digital computer is introduced for predicting annular backpressure and equivalent fluid density profiles associated with controlled gas kicks. We point out the effects of volumetric behavior of extraneous gases in annular flow and related field phenomena on equivalent fluid densities at a critical depth. The investigation indicated that equivalent fluid densities at a critical depth are of significance and should receive consideration in the control of threatened blowouts and in the design of drilling programs. Theoretical Considerations The mechanism of vertical gas flow through an annulus is governed by the PVT properties of the fluid, the pressure distribution within the system, the fluid flow rates and the geometry of flow. Due to the numerous variables involved in this type of problem, certain assumptions were imposed in deriving the mathematical model and in establishing the solutions. Two gases, characterized by specific gravities of 0.6 and 0.7, were selected to typify Gulf Coast reservoir fluids. The gas intrustion entered the wellbore as an immiscible 'References given at end of paper. JOURNAL OF PETROLEUM TECHNOLOGY

Jan 1, 1969

By Å. Sterten, R. Tunold, J. Brun, K. Dalatun

c axis compression behavior of beryllium single crystals at three purity levels under hydrostatic pressures up to 27 kbars was determined. Extensive non-basal slip, observed by two-surface trace analysis and transmission electron microscopy, occurred under a hydrostatic pressure of about 12 kbars (175 ksi) for the high-purity (twelve-zone pass) material and at about 19 kbar (275 ksi) for the lower-purity (zone-leveled) material. Prismatic loops with a (c + a) Burgers vector were observed in association with second-phase parti- A principal factor limiting the use of beryllium is its brittle behavior when tested at the usual strain rates (E = 10-4 sec- 1) at temperatures below about 200°C and under impact conditions at temperatures in excess of 200°C. It has been proposed' that the brittle-ness of beryllium is associated with the lack of a sufficient number of independent slip modes and the absence of a slip mode with a Burgers vector out of the basal plane [presumably (c + a) pyramidal slip mode] and to the ease with which beryllium cleaves on the basal and second-order prism planes. The absence of pyramidal slip has been attributed to a high Peierls-Nabarro stress associated with the motion of dislocations with a (c + a) vector and the ease with which cleavage occurs on the basal and second-order prism planes. The experimental evidence in support of the proposed explanation for the brittleness of beryllium is far from complete; for example, that the ductile-to-brittle transition in polycrystalline beryllium is associated with the operation of profuse (C + a) slip has not been unequivocally established. The occurrence of (c + a) slip ({1122}(1123)) has been experimentally established2-5 under conditions where basal and prism cleavage are restricted in a c axis compression test. In these investigations (C +a) slip was found in high-purity beryllium single crystals tested in c axis compression* at 200°C and in Be-4.4 pct Cu and Be-5.2 pct cles in the lower-purity materials tested. The loops were related to surface "extrusions" observed on many of these same specimens. Nonbasal dislocations operating on (1122) planes with a (c + a) Burgers vector were observed. The presence of c and a dislocations together with (c + a) dislocations suggests that the (c + a) dislocations dissociate presumably on unloading or after failure of the test crystals to c and a dislocations. terial, (c + a) slip has only been observed near the the fracture4 surface in room-temperature c axis compression tests. Fracture in these tests occurs without measurable plastic flow, as determined with a strain sensitivity of 10"6. Since it has been shown for many metals that the application of hydrostatic pressure suppresses fracture,?-' it was felt that studying the behavior of unalloyed beryllium single crystals stressed in c axis compression under a hydrostatic pressure would reveal whether (c + a) can occur if fracture was prevented, and that it might elucidate the role of (c + a) slip in the ductile to brittle transition. Evidence that (C + a) slip is associated with increased ductility in a high-pressure environment has been found in stress-strain tests on poly crystalline beryllium.10 The present paper describes a study on the influence of a hydrostatic pressure environment on the occurrence of (c + a) slip in beryllium single crystals. Material of two purity levels was tested in c axis compression over the pressure range ambient to about 27.5 kbars.* 1) MATERIAL PREPARATION AND CHARACTERIZATION Two lots of low-purity single-crystal beryllium were used. The first lot was "ingot secondary refined grade" and designated lot A. The second lot (lot B) was produced by a two floating zone pass zone-leveling operation in an argon-filled sealed quartz apparatus on a 1-in.-diam by 12-in.-long bar of Pechiney secondary refined-grade vacuum-cast and hot-extruded material. The high-purity material (lot C) was made by traversing twelve floating zone passes through a similar bar of Pechiney secondary refined-grade vacuum-cast and hot-extruded material. In a series of spark cutting and lapping procedures,11 single-. crystal specimens some 0.12 in. sq by 0.30 in. high were made with the sides Parallel to the first- and second-order prism planes and the basal plane within 3' of arc of the top and bottom surfaces of the specimen. Such an accurate orientation is necessary because of the large difference in resolved shear stress

Jan 1, 1970

By H. I. Aaronson, C. Wells

Configurations of ferrite crystals have been found in a plain carbon steel which appear to have resulted from the nucleation of new ferrite crystals at the interphase boundaries of previously formed crystals despite the high carbon concentrations which necessarily develop at these boundaries. This phenomenon has been termed sympathetic nucleation. An attempt has been made to reconcile the occurrence of sympathetic nu-cleation with current nucleation theory. THIS investigation is one of a series on the formation of proeutectoid ferrite from austenite. From the viewpoint of chemical composition, this reaction consists of the nucleation and diffusional growth of crystals of carbon-poor ferrite within a matrix of carbon-rich austenite. The austenite adjacent to the austenite-ferrite boundaries will be greatly enriched in carbon, approximately to the value of the y/(a + y) equilibrium curve or its metastable extrapolation at the temperature of transformation. Those areas of austenite appreciably farther removed from the growing ferrite, on the other hand, will be relatively unaltered in composition, especially at the earlier stages of transformation. Since rates of nucleation are considered to decrease exponentially with decreasing supersaturation,' the frequency with which ferrite nuclei appear at austenite-ferrite boundaries should be negligible in relation to that at which they form in other regions of the austenite. During this investigation, however, many groupings of ferrite crystals have been found which appear to have resulted from the nucleation of ferrite at austenite-ferrite boundaries. This phenomenon has been given the name of sympathetic 71.1tcleation. A number of micrographs of morphological configurations caused by sympathetic nucleation will be presented, after which an explanation for this reaction will be proposed in terms of current nucleation theory. Some of the structures to be considered are composed of bainite, an aggregate of ferrite and carbide, rather than of ferrite. Since ferrite and bainite differ only in that bainite forms under conditions which result in the nucleation of carbides behind the advancing austenite-ferrite boundaries,' it will usually be unnecessary, for the purpose of this paper, to distinguish between the two reaction products. All studies were performed on an electric furnace steel (obtained from the Vanadium Alloy Steel Co.) containing 0.29 pct C, 0.76 pct Mn, 0.25 pct Si, 0.005 pct P, and 0.007 pct S. The alloy was cast as a 150 Ib, 7x7 in. cross section ingot and forged into bars 2x2 in. in cross section. These bars were homogenized for 48 hr at 1250°C in an Endo-Gas atmosphere. The depth to which decarburization penetrated during this heat treatment was determined by chemical and microscopic analyses and the affected metal was removed by machining. Specimens for isothermal transformation studies were cut from the remaining material; most of these specimens were 1/2x1/4X1/16 in., though some with a thickness of 1/32 in. were prepared for use at the shorter reaction times and lower reaction temperatures. Specimens were austenitized for 30 min at 1300°C, isothermally reacted for various times at temperatures ranging from 775" to 475 "C, and then quenched in iced water. The austenite grain sizes within individual specimens ranged from ASTM Nos. 1 through —4. A commercial heat-treating salt which was continuously deoxidized by an immersed graphite crucible served to minimize the loss of carbon during austenitizing; thick covers of powdered graphite and immersed graphite rods effectively prevented decarburization in the lead pots employed for the isothermal reaction treatments. The heat-treated specimens were sectioned and mounted in Bakelite. Following the completion of standard grinding and mechanical polishing procedures, the specimens were electrolytically polished with a Buehler-Waisman apparatus and etched in 2 pct nital. Experimental Results Rules of Evidence for Sympathetic Nucleation—On the basis of observations made on a single plane of polish, one precipitate crystal may be considered to have been sympathetically nucleated at the inter-phase boundary of another precipitate crystal when the following conditions are fulfilled: 1) The sympathetically nucleated crystal is not in contact with a grain boundary or a subboundary in the matrix phase. 2) The shape, size, and location of the crystal at whose boundary sympathetic nucleation occurred (hereafter termed the base crystal) and the crystal formed by sympathetic nucleation substantially pre-clude the possibility that the plane of polish em-ployed may have concealed the fact that both crys-tals actually nucleated at a grain boundary or a sub-boundary in the matrix phase.

Jan 1, 1957

By N. A. Gokcen

The construction and operation of a simple and accurate vacuum-fusion apparatus are described in detail. Absolute accuracy of the oxygen analysis has been determined by the reduction of oxides weighed to 20.01 mg. The Bureau of Standards steel samples have been analyzed repeatedly, and their inadequacy for the acceptable range of oxygen is presented. The limits of interference of manganese, aluminum, and titanium, and the effects of tin and water-cooling of the furnace tube have been investigated in detail. ANALYSIS by the vacuum-fusion method consists of melting a sample in a degassed graphite crucible under high vacuum and extracting oxygen as carbon monoxide, and nitrogen and hydrogen as gaseous elements. The resulting gas mixture is analyzed for its constituents, from which oxygen, nitrogen, and frequently hydrogen may be determined within 1/2 hr or less. The history and summary of methods1-4 and extensive reviews of literature'.' for the determination of gases in metals have been published in detail. The foundation of the modern vacuum-fusion method of analysis was laid by Jordan and Eckman,11 and Oberhoffer and his associates.1, 10 Diergarten,11, 12 Meyer,13 Thanheiser et al.,14, 15 Ericson and Benedicks,16 Ziegler,17, 18 Sloman,16-23 Thompson et al.,24 and later many others contributed to the improvement, accuracy, and limitations of the method. In some investigations, however, the limitations of the procedure and the errors involved in the analysis require further critical examination and evaluation. In many apparatuses, lunnecessarily complicated and cumbersome features and elaborate precautionary measures do not have conclusive advantages. The purpose of this invest:igation was, therefore, a) to construct a very simple and accurate apparatus, b) to determine the absolute accuracy of results, c) to establish the limits of interference of manganese. aluminum, and titanium, d) to reexamine critically the reduction and recovery of oxygen from oxide powders of various sizes, and e) to evaluate critically the eight steels of the Bureau of Standards."' Apparatus The apparatus used in this investigation is shown in Fig. 1. It has been used for over three years, during which several modifications were made. A brief description of the apparatus is as follows. The transparent silica or Vycor tube, E, is joined to the Pyrex head, B, by mean of a face to face ground joint sealed with mercury. A similarly sealed ball and socket joint would also have been satisfactory. A standard tapered ground joint, successfully used by some investigators, was tried, but in the absence of grease or vacuum cement it was very difficult to disassemble the joint. The graphite crucible, G, 15/16 or l 1/8 in. OD, 2 1/2 or 3 in. high, 1/10 in. wall, shown enlarged in Fig. 3a, is made from the rods containing less than 0.08 pet ash. Two baffles, overlapping sufficiently to prevent spattering, are inserted in two opposite slots cut on a band saw. Two small holes in the baffles permit the temperature measurement of the melt. A second type of crucible, Fig. 2, G, shown enlarged in Fig. 3b, is also satisfactory, though not as convenient as the crucible shown in Fig. 3a. Somewhat similar but more elaborate crucibles with baffles were first tried by Ericson and Benedicks,'" but were abandoned in favor of a crucible with a stopper and a peripheral graphite powder filter. Various versions of their crucible with a stopper have later been used by other analysts, 10-27, 27-30 The crucible is packed directly in E, Figs. 1 and 2, with —35 + 48 graphite powder for shielding and insulation. A minimum layer of 7 mm of powder is necessary for keeping E cool and minimizing the blank. The first use of graphite powder was made by Sloman,10-23 Who found that —200 mesh was the most satisfactory. The author tried various size powders from +20 to —100 mesh and found that a) particles of 28 mesh or larger were not sufficiently insulating and were heated by the induction current, b) the powder finer than 60 mesh packed too much and did not readily permit the escape of gases even when the crucible was heated very slowly; hence, the powder was occasionally blown out of the side in the crucible and in the mercury pump. The optimum size powder is, therefore, 35 to 48 mesh size or 0.4 mm in average diameter. The furnace is designed to eliminate excessive amounts of

Jan 1, 1959

By Walter C. Lawson

THE primary objective in laying track in panel sections is to reduce the number of track laborers required. This is possible because the work is mechanized. Moreover, because the work is mechanized and each of the operations needs only a few men, and each is self-contained, the work can be carried on at night as well as in daylight; therefore, the method provides a means of preparing tracks on more than one shift. The laying of tracks in open pits and quarries in panel sections is not new but new methods have been made possible by the introduction of new types of equipment. The purpose of this paper is to describe the methods that are followed in' the Morenci open pit. GENERAL MINING OPERATIONS Full-scale ore production at Morenci is about 50,000 tons daily. The normal yearly output of ore and waste is 32,000,000 tons, of which 30,000,000 tons is handled by rail haulage. This requires the building of approximately 47 miles of loading and other temporary tracks during a 12 months' period (Fig I). Broken ore and waste, is loaded., into 90-ton capacity dump cars with 5-cu-yd full-revolving electric shovels. Shovel banks are uniformly 50 ft high:. They are blasted- with churn drill holes, and the broken material from a blast is loaded out with two shovel cuts, the first one being called (locally) the "splatter" cut and the second one the "clean-up" or "face-up" cut. When a shovel is making its clean-up cut, the loading track is about 70 ft from the toe of the bank and, under normal conditions, a bank is blasted against it without removing the track. It is thus evident that each track is used for two shovel cuts before relocation is necessary, inasmuch as a single position serves for both the clean-up cut prior to blasting and for the splatter cut following the blast. The normal advance of a solid bench by a single blast is 40 ft (Fig 2). PREPARATION OF PANEL GRADE In preparation of panel grades bulldozers and rooters are used for the bulk of the work and an auto-patrol road grader for the final stage. At Morenci, bulldozers have always been used for track-grade preparation, but before the introduction of the other two types of equipment grades were uneven and irregular at best, and always necessitated a big gang of track laborers to hand-block under the ties with rocks after a track was laid into place. High blocking also made poor track because of instability and caused frequent derailments. Under these conditions derailments were generally bad as re-railing became difficult. Much track was torn up and many ties broken in the process. The inadequacy of the hand-blocked track, together with the inefficiency of hand blocking, constantly pointed to the desirability of reducing the amount of labor required, so various means were tried to improve conditions, such as wood

Jan 1, 1947

By Cyril Stanley Smith

THE art of metallography is mature and the forms in which various micro-constituents appear are well known. Investigations almost without end have disclosed the importance of the exact manner of distribution of phases on the physical properties and usefulness of an alloy. Surprisingly, however, relatively little attention has been paid to the forces that are responsible for the particular and varied spatial arrangements of grains and phases that are observed. Like the anatomist, the metallurgist has been more concerned with form and function than with origins. In this paper it is proposed to develop the simple concept that many microstructures result from an attempted approach to equilibrium between phase and grain interfaces whose surface tensions geometrically balance each other at the points and along the lines where they meet. From this follows a number of principles which may prove to be of interest to the metallographer and of practical use in explaining failures and in designing alloys for particular service. In general, the discussion will be limited to structures obtained after full annealing. The simple principles do not apply to structures resulting from Widmanstatten mechanisms in precipitation, or to other structures not in local equilibrium and in which lattice coherency is a determining factor. INTERFACIAL TENSION Much has been written by physical chemists about the free energy of surfaces, which manifests itself as a measurable surface tension. Two- and three-phase interfaces in fluids seek a condition of minimum energy and approach a geometrical configuration in which the various forces are in vectorial balance.* Measurement of the angles established between the interfaces when in equilibrium provides a quantitative value for the relative value of the surface forces involved. The case of two fluids meeting at the surface of a solid (of great importance in connection with the flotation of minerals) has often been studied, but there have been few investigations of the equally definite interface between two or more crystals of a single solid phase, or the more complex cases where crystal grains of more than one phase are involved. The principles are best illustrated by considering first the case of two and three immiscible liquids. If, as in Fig I, a liquid, 2, is dropped into a less dense liquid, I, it will form a sphere-if gravity and viscosity can be ignored-for in this shape the interface has the smallest possible area. If these two phases should together encounter a third phase in which they are both immiscible, the geometry will change to become that which gives the lowest total energy for all three interfaces. Thus, if the spherical drop of liquid, falling through r, eventually reaches the interface between liquids 3 and I (we are assuming that the density of 3 is greater than 2, and 2 than I), it will assume the shape of a lens, the angle

Jan 1, 1948

By S. C. Tadolini

"Roof bolts are the primary means of roof support in underground mines in the United States. Presently, post installation loads are measured on about 10% of the expansion anchor and combination bolts by using standard torque wrenches that Unit the accuracy of the measurements to about ±30%. No system has been available for measuring the loads generated on full-column resin grouted bolts. Mine roof bolts are long, slender, non-uniformly sized, roughly forged, and placed in a corrosive environment, creating obstacles for researchers trying to utilize ultrasonic reflection techniques to measure strain. A complete measurement system has now been developed by the U.S. Bureau of Mines, Denver Research Center. This system is being used successfully in determining loads measured on expansion anchor and combination bolting systems, examining the transfer mechanics of full-column, resin-grouted bolts, and measuring loads generated on bolts in an underground roadway support system.IntroductionMillions of roof bolts are used each year to provide structural support in underground U.S. metal, non-metal, and coal mines. Approximately 45% of the bolts used are expansion anchor, 45% are resin-assisted combination or full-column resin-grouted, and 10% are friction anchored. The effectiveness of these bolting types is dependent on a number of factors including rock density, bolt length, in situ stresses, rock properties, bolt pattern, installation tension, etc. When implementing expansion anchor and resin assisted combination bolts , installation and post-installation tension, or load, is a major determinant of support quality and subsequent behaviour of the reinforced roof. The method by which these systems carry roof loads is well understood and documented(1,2).The importance of these installation and long-term bolt tension measurements is well recognized and are required in the federal government regulations(3). A statistical sample of the bolts, lout of 4 during installation and lout of 10 inby the last open crosscut, is required to be measured using current torque wrench technology. The disadvantages of this system are the disturbance and weakening of the anchorage and limitations of accuracy to approximately ± 30%. The method by which resin-grouted bolting systems carry roof loads is much less understood, mainly because testing procedures used to evaluate point-anchor systems are not effective on resin-grouted bolts.Due to these problems, the U.S. Bureau of Mines designed a measurement technique that provided a highly accurate, low cost-per- bolt system that led to the development of ultrasonic pulse echo instrumentation. The original system was designed to measure the tension only on expansion anchor bolts. Recent developments and system modifications have permitted measurements on resin-assisted and full-column resin-grouted bolts. The use of these types of support systems has been increasing steadily in underground coal mines.The development of this instrumentation has provided laboratory and field results that help to explain the mechanics and relationships between the applied loads and the interaction between the grouted bolt system consisting of the bolt tendon, grout, and rock."

Jan 1, 1990

By M. L. Holzworth, Philip R. Sperry, Paul A. Beck

INTRODUCTION THE basic work of Z. Jeffries1,2,3 has long ago established the main features of grain growth in the presence of a dispersed second phase. Working with sintered specimens of initially fine grained tungsten, to which various amounts of thoria have been added, Jeffries found that grain growth was inhabited, that is, practically prevented, up to a certain annealing temperature. When this temperature, which increased with the thoria content, was exceeded, extremely large grains developed abruptly from the fine grained matrix. Such a "coarsening temperature" was later found by Gross mann13,14 in certain types of steel, while Bain showed" that in other steels grain growth was gradual, without inhibition and abrupt coarsening. Later work16,17,18,19,21 demonstrated the connection between coarsening and aluminum additions. The viewpoint that the direct cause of inhibition and coarsening in aluminum killed steels is a fine dispersion of aluminum oxide21 appears to be held quite generally, although some doubts have been voiced even very recently.20 In steels with Ti additions the titanium carbide phase is considered responsible for the inhibition effects found.20 The coarsening temperature increases, with the titanium content. That coarsening may occur, as a result of certain heat treatments, even in low carbon rimmed sheet steel, was shown by Samuels,22 He also detected coarsening in a steel ingot of similar composition, after giving it the same heat treatment as that used by him for the sheet material, In this instance the identity of the inhibiting phase has not been determined, However, Tangerding found 23 that even the few small carbide particles, which occur in carbonyl iron, have a very marked inhibitive effect. As a result of an oxidizing anneal at 850°C, large grains begin to form at the surface of the carbonyl iron specimen, and gradually grow inward as the subsurface oxidation of the carbide particles progresses and eliminates the obstruction, The carbide particles can be removed also by annealing in hydrogen, with similar results. But if the oxidizing anneal of 10 hr at 850°C in air, is followed by annealing in hydrogen for 75 hr at the same temperature, grain growth is more spectacular; usually the whole specimen is transformed into a single crystal (approx. 1,5 cm X 5 cm). The reversed procedure, that is, hydrogen annealing followed by oxidizing annealing leads to smaller grains. Tangerding arrived at the logical conclusion that there must have been in his specimens some additional obstruction to grain growth resulting from a minor impurity, other than carbon. It seems likely that this obstruction was caused by an oxide formed during the oxidizing anneal and gradually reduced during the subsequent hydrogen-annealing. Other instances of grain growth inhibition of varying severity, associated with a dispersed second phase, have been described by several authors. Notable examples: lead with 0.06 pct Cu or Ni,24 cartridge brass with 0.12 pct Cr,25 or with up to 0.15

Jan 1, 1948

"Above ground, elevated belt conveyors that span more than 200 m (656 ft) between support points can cross valleys, rivers, forests and buildings with a minimal footprint. The cable bridge conveyor (CBC) is a new type of suspension bridge based belt conveyor system that has long spans between support points. It combines a typical belt conveyor and an improved simple suspension bridge to form a conveyor bridge. The improved simple suspension bridge places a widened bridge deck directly on suspended cables, without the need for high truss towers. The benefits include reduced cost and increase aerodynamic stability compared to conventional suspension bridges. The CBC’s compatibility with current belt conveyors allows versatility in application.A belt conveyor is a ubiquitous material handling system. Conveyors can be placed directly on ground or elevated above ground by support structures. Considerations of cost, design, environment, civil work, safety and process requirements are all factors in choosing the ground-based or elevated conveyors (Zhang, 2014). The ground-based conveyor has the lowest structural cost when the conveyor is placed on an existing road. Maintenance access is easy and straightforward. Compared to the groundbased conveyor, the elevated conveyor can cross existing buildings and structures, give passage to traffic beneath the conveyor, has a smaller footprint and requires less civil work to pass mountainous areas. The drawback of the elevated conveyor is higher structural cost, which can be compared with savings in civil work and other benefits. Conventional elevated conveyors are supported by rigid truss-type structures, with a typical span of 15 to 25 m (50 to 82 ft) between concrete support bents or steel trestles. Triangular truss, using steel pipes instead of hot rolled steel sections, is more efficient. The typical span of a triangular truss-supported conveyor is around 30 to 40 m (100 to 130 ft), while the weight is about 10 percent less than conventional box truss with a shorter span (Jennings, 2013).Long-span elevated structures based on suspension bridge is another step forward in increasing the distance between support bents, reaching 100 to 400 m (330 to 1,312 ft) and beyond. The wide distance between the support points of an elevated conveyor offers unique benefits. The conveyor can cross rivers, valleys, highways, forests and other obstacles with minimal footprint and reduced civil work. The versatility from long-span conveyors makes bulk material transportation over previously impossible terrains now a feasible option."

Jan 1, 2014

By D. R. Baughman

Copper oxide deposits that may be considered for in situ leaching exist in unique geologic settings, different from uranium deposits. A large number of interrelated factors must be considered in wellfield design. Many of these factors are hard to quantify and are directly related to geologic features of the orebody. This paper discusses some of the important factors in wellfield design and suggests an outline for a design procedure.

Jan 1, 1988

By T. A. Edison

A distinct hydrocarbon maturation anomaly coincides with the Gold Acres open pit, Nevada (Figure 1). Both atomic hydrogen to carbon (H-C) ratios and reflectance measurements of contained organic matter indicate significantly higher maturity in samples collected within the confines of the open pit than in samples from the surrounding region (not shown in Figure 1).

Jan 1, 1987

By M. Irish

This paper describes the emergency water control measures used at Pegasus Gold's Zortman Landusky mine during the September 1986 flood. The amount of solution stored increased by approximately 78 165 m3 due to receiving 0.2134 m of rain in a 24 hour period. Three methods of water disposal will be discussed including continuous chlorination, batch chlorination, and reverse osmosis. A water management program will also be discussed.

Jan 1, 1988

By H. H. Kleizen

The operation range and efficiency of dewatering apparatus are important factors in the selection of an apparatus for a given purpose. In this paper theories are presented allowing to predict these basic characteristics for different dewatering apparatus and compared with experimental and practical data obtained on coal and ore slurries.

Jan 1, 1989

By David M. Holmes-Smith

Many attempts have been made to design and build an AUV that is small, meets the sensing objectives and is cost effective. Many inventors have already designed smaller vehicles but the problem observed is an increased vehicle instability resulting in instrument instability where data gathered is not trustworthy. Additional problems include instrument weight to vehicle weight ratios and the lack of space for power storage and electrical components. The UFOceanic seeks to remedy these concerns by employing a completely different design and propulsion system. Still in the design stage ? now with a mock-up unit for testing, the results are encouraging. We have chosen a very low voltage embedded systems design using multiple PIC processors and fuzzy logic programming. We are designing the craft to rotate for stability and to provide friction reduction to minimize the need for instrument stability compensation and propulsion power. Additionally, we are looking and experimenting with a number of power plant drive systems including flywheels, GNP (plasma), fuel cells and more conventional systems. We of course plan for the UFOceanic to run for months at a time supported by a self-charging system.

Jan 1, 2001

By J. M. Keane

Critical to successful dump and heap leaching for copper is an adequate testing program for evaluation of the applicable parameters. This paper deals with testing methods to establish best conditions for dump and heap leaching of copper so that commercial operations can proceed on a rational basis. Discussion is also offered of ore occurrences suitable for dump and heap leaching.

Jan 1, 1985

By Richard Harrison, Frank Lim

"Lifting of slurry from the seabed mining machine to the surface production vessel is a critical element of any deepwater seabed mining system. A Vertical Transport System (VTS) comprises pump(s), riser string, connectors and hang-off assembly as its main components, but it is the pipe material, riser configuration and installation method that often attract the most discussions.This presentation will feature important VTS design work 2H has done over the years for different stakeholders, and highlight the work carried out as a partner to the EU funded Blue Mining Joint Industry Project.The key challenges faced by a deepwater VTS are:??High riser payload??Large deck space for storing riser joints??Long time to deploy and retrieve riser??Uncertain metocean conditions??Vortex induced vibrations??Weld and connector fatigueIncreasing the water depth further sees the longer and increasingly ‘springy’ riser experiencing axial resonance caused by wave induced vessel heave motions being close to the riser resonant period. This can lead to snatch loading and fatigue failure in the riser.The presentation will discuss the above design issues, analysis requirements and provide guidance on pump/riser selection. Solutions to mitigate the resonant response issues will also be proposed.."

Jan 1, 2017

Agenda 1.Energy consumption and energy costs ?focus and failings 2.Energy efficiency methodologies, people and supporting tools 3.Energy cost saving case studies from three minerals processing plants 4.The operations team and the supporting role of Operations IT 5.Conclusion: Reducing energy consumption and energy costs There are many good Energy Efficiency Methodologies ?Energy and GHG Emissions, Management Guidance Document, The Mining Association of Canada ?Energy Savings Toolbox ?An Energy Audit Manual and Tool, Canadian Industry Program for Energy Conservation (CIPEC) ?Lean and Energy Toolkit, Achieving Process Excellence Using Less Energy, www.epa.gov/lean ?Energy Efficiency Opportunities Assessment Handbook, www.energyefficiencyopportunities.gov.au

May 1, 2010

By S. Rajendran

Much advance has been made in offshore hydrocarbon exploration and exploitation in India. But the same amount of success could not be achieved in the case of other offshore minerals which are amenable for mining. However, employing present technology, there should not be any difficulty in successful exploitation with minimum environmental hazards. A demonstration is provided by considering the conditions prevailing in the Kerala offshore (southwest coast of India) scenario of monazite, ilmenite, phosphatic mud and calcareous deposits. Mud banks are unique phenomenon of the Kerala coast during monsoon season. Acting as barriers to waves, mud banks protect portions of the beaches from being eroded and trap sediments from either side facilitating growth of adjacent beach. The easy minable possibilities of the phosphatic mud during non-monsoon season with less pollution hazards and dumping back the waste material after processing for phosphate at the breaker zones to reduce the erosional effects on the coast make the exploitation economic and ecofriendly unlike the benefication of the lowgrade phosphate ores on land on a comparatively larger area and subsequent crushing, transport and resulting pollution.

Jan 1, 1993