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By T. P. Papazoglou, N. A. D. Parlee, W. C. Phelps

HE high vapor pressures of metals such as lead, calcium, lithium, bismuth, and magnesium at steel-making temperatures present experimental problems which have thus far rendered it almost impossible to obtain really reliable data for their solubilities in liquid iron. Many investigators have attempted to equilibrate liquid iron in the same crucible with the undissolved liquid phase of such volatile metals. The published results,l-6 although useful, are often questionable on the grounds of not being obtained under true equilibrium conditions. Such information is not always of practical value in any case since the equilibrium vapor pressure is often several atmospheres and steel is not currently made at these pressures. Solubility measurements at lower partial pressures (< 1 atm) appeared to be more practical and easier to make. These data could be used to calculate solubilities at other pressures where Henry&apos;s Law is obeyed, and to estimate solubilities under other conditions of temperature and pressure with useful accuracy. This note outlines the development of a general technique for the measurement of solubilities in systems of this kind. The method involves equilibration of the high-boiling metal at known temperatures with the vapors of a low-boiling metal at known partial pressures. Analyses of quenched samples provide vapor pressure-solubility data and make calculations of alloy thermodynamics possible. The principle involved is similar to the closed-system diffusion-transport method which is difficult to apply with most high-melting liquid metals like iron, due to closure problems. A two-zone horizontal (molybdenum wire element) tube furnace, Fig. 1, provides two constant-temperature zones in a reaction tuve (3/4 in. ID by 1 in. OD by 36 in.). A high-boiling metal sample, 9, introduced in the higher-temperature zone, is maintained at temperature T1, and a volatile metal sample, 7, in the lower-temperature zone, is held at T2. A stream of argon with 10 pct hydrogen is passed via flowmeters, 1, and mixing-drying towers, 2 and 3. through the reaction tube at a favorable flowrate and acts as a carrier gas which entrains vapor from the volatile liquid metal at a specific constant partial pressure. The gas mixture passes through a system of constrictions, 6 and 8, to the higher-temperature zone, establishes intimate contact with the high-boiling liquid sample, 9, and exits through a small condenser tube. The entire system is at (nearly) atmospheric pressure and the volume of carrier gas passed is measured with a wet gas meter. When the high-boiling sample attains equilibrium with the vapor phase, both samples are removed and quenched. Analysis of the high-boiling sample for solute content reveals its solubility for the low-boiling metal at a vapor pressure calculated from carrier-gas volume and either a) weight loss of volatile metal or 6) weight gain of high-boiling sample plus condenser (which collects the undissolved vapors). To test the capabilities of the method, liquid silver at 1403&apos;C was equilibrated with lead vapor at various partial pressures. The relatively simple Pb-Ag system was particularly suitable for uncovering experimental problems and providing the first step toward investigations with more volatile metals and more difficult combinations.

Jan 1, 1965

By B. E. Eakin, A. L. Lee, M. H. Gonzalez

Expeximental viscosity and density data of lour natural gases are presented for temperatures from WO to 340F and pressures from 100 to 8.000 psia. A correlation is also discussed and results reported. INTRODUCTION This investigation is one of several efforts by the authors to provide viscosity data for pure hydrocarbons and mixtures. Results of some pure hydrocarbons and their mix tures have been presented." Several predictive methods and correlations have also been reported.&apos;," This paper presents the experimental viscosity and density data of four natural gases and confirms a correlation in a previous study. APPARATUS The viscometer was described previously. 2,6 A bank of stainless steel pycnometers was included to determine density in conjunction with the viscosity measurements (Fig. I). DATA AND MATERIALS The natural gases were furnished by the Atlantic Richfield Co. (Samples 1 and 21, the Continental Oil Co. (Sample 3) and the Pan American Petroleum Corp. (Sample 4). Table 1 shows the composition of these gases obtained by mass spectrometer analysis. The pure component viscosity data used in the correlation have been published."".&apos;"&apos;, &apos;" Experimental and calculated viscosity data for the natural gases are presented in Tables 2 through 5. CORRELATION Starling and Ellington"&apos; have reported several semi-empirical expressions based to a certain extent on the theory of viscosity advanced by Born and Green.&apos; The final expression presented by Starling and Ellingto&apos;n is: i&apos;. (micropoise) -- /t,, exp rX(7&apos;) p ..... (I) Eq. 1 was modified by Lee et 01." to represent mixture and pure component data simultaneously. This equation has the form: F = K exp [XpY] :.........(2) where K=- (7.77 i 0.0063M)Ti 122.4 + 12.9M +T .................(3) &apos; &apos; &apos; X= 2.57 + ---1914.5+ 0.0095M .... (4) Y = 1.11 -r 0.04 X ........(5) Over the pressure and temperature range studied in this investigation, this equation represents the data on methane, ethane, propane, n-butane and four methane-n-butane mixtures with a standard deviation* of ? 1.89 per cent. Density data by Sage and Lacey" were used to fit the equations. Eq. 2 gives reliable values of the viscosity of light hydrocarbons without prior knowledge of experimental viscosity values, but accurate density data must be available. Eq. 2 was used to predict viscosity values for the natural gases studied in this paper. The particular set of parameters contained in Eqs. 3 through 5 gave values that reproduced experimental data within 25 per cent. Needless to say, in using Eq. 2 better density values will give better viscosity results. However, those engineers who do not have accurate density values at hand or the time, or such facilities as a library, computer, etc. readily available, may feel uneasy in using Eq. 2. Therefore, the authors sought the easiest but by no means best density prediction method, which was reported by Kaf 30 years ago. A set of density values, which were calculated based on Kay&apos;s method, and a generalized compressibility factor chart were used to fit Eq. 2. The results are:

Jan 1, 1967

By G. H. Lair, B. J. Langford, S. H. Rockwood

Volumetric reservoir analysis is dependent upon a firm relationship between porosity, connate water, and net pay. Capillary presswe data on core samples interrelate these three factors. It is shown that other reservoir problems may be resolved: (I) whether water production is indigenous or extraneous to the oil producing interval, (2) an oil-water contact is being approached, and (3) whether the oil-water contact is remotely situated. INTRODUCTION Volumetric analysis of carbonate reservoirs challenges the ingenuity of the reservoir engineer due to an absence of data on the minimum oil-bearing and oil-producing pores of a given reservoir rock. Many studies with this as the ultimate objective are available on the physical characteristics and fluid-flow behaviors of the carbonate reservoir. Some of these publications are: Hassler, Brunner and Deahl&apos;s1 study of the role of capillarity in oil production; Jan Law&apos;s&apos; and A. C. Bulnes3 statistical treatment of core analysis data; Chalkley&apos;s method4,5 or estimating specific surface areas and porosity; Walter Rose&apos;s9 report on porosity, reserves, and recovery; Archie&apos;s78 tex-tural classification of carbonate rocks; Stewart and Spurlock&apos;s9 large core analysis; Purcell&apos;sl0 mercury injection method in studying capillary pressure phenomena; Stewart, Craig, and Morse&apos;s" model multiple-phase flow test in investigating the relative permeability effect; and Fatt&apos;s12 illumi-nating network model of porous me-dia. The present study shows that the static reservoir parameters of porosity, connate water, and net productive thickness may be interrelated by utilizing a statistical arrangement of mercury capillary pressure data in addition to routine core analysis. This report summarizes the techniques that are followed to obtain these relations which are applicable to carbonate and sandstone reservoirs that do not contain clays. Capillary pressure statistical studies may be extended to include clay-bearing rocks by utilizing water capillary pressure data. POROSITY It is necessary that the laboratory determine the porosity value that includes the pores that are filled with hydrocarbons and water in the reservoir. This is the reservoir&apos;s total porosity. When true total porosity values are not available, correlations between porosity and capillary pressure characteristics lose their significance since they cannot be related through oil-base mud core data to the porosity and connate water values found in reservoirs. Methods used to obtain reliable porosity data will not be discussed; however, care should be exercised in selecting samples for measurement. In homogeneously porous formations, small core plugs sampled frequently will furnish adequate information. Where heterogeneity, particularly vugginess, is present, large-core porosity data may be required; in such reservoirs a suite of capillary pressure samples may be selected from small plugs. CAPILLARY PRESSURE Capillary pressure data provide a method for relating two carbonate reservoir parameters, porosity and connate water saturation, which in turn permit delineation of productive rock types necessary for selecting the third parameter, productive thickness. Specific applications of capillary pressure data to petroleum reservoirs were suggested by Archie8 and Pur-cell."&apos; Their work demonstrated that in preferentially water-wet rock, porc

Jan 1, 1958

By W. T. Lankford, Low J. R., Gensamer M.

The problem of sheet metal formability is one which has received a vast amount of attention during recent years. In spite of the great amount of study and experimental work which has been devoted to this problem, many of its fundamental aspects are still not well understood. No generally satisfactory test has been developed which is capable of providing a reasonably adequate evaluation of sheet metal formability, particularly in borderline cases. Anomalies persistently arise in which a lot of supposedly satisfactory material exhibits excessive breakage when formed. This lack of suitable technological tests greatly hinders the design of new parts and the substitution of new materials in parts of existing design, frequently necessitating considerable costly trial and error experimentation on an actual production basis. When, at the beginning of World War 11, it became apparent that mass production methods of forming would bc required in the aircraft industry if the large numbers of military aircraft needed were to be supplied, renewed attention was focussed on the problem of sheet metal formability. It was widely recognized that the formability requirements placed on sheet metals had been steadily increasing in severity through the years, especially as greater and greater emphasis was placed on streamlined designs with the resultant freer application of doubly curved surfaces. The recent advent of several new high strength aluminum alloys of more limited formability than some of the older alloys also served to emphasize the need for new approaches to the problem. It seemed evident that progress in the technology of sheet metal forming would depend to a great extent on the development of more reliable criteria for the evaluation of formability. Although the problem is admittedly very complex, the most logical approach appeared to be through studies of the fundamental material properties of sheet metals, especially under complex stress conditions simulating those prevailing in actual forming operations. Most previous investigations have failed to make full use of existing knowledge of fundamental material properties, and in many instances have attempted correlations with properties which are now recognized as being ambiguous in nature. This investigation was undertaken, therefore, with the aim of developing methods for the study of the flow and fracture of sheet meta1s under combined stresses, and of making use of such methods as might be developed in

Jan 1, 1947

By Thomas. Lisa, Mark Coleman

Schenck Process is an established customer-driven solutions provider, utilising its knowledge, expertise and technologies to transform production processes. Operating across several industries Schenck Process have developed quality solutions from their range of equipment to solve problems and fill holes in other people’s processes. In the non-ferrous metals industries Schenck Process have been using their Clyde Brand solutions in Pneumatic Transport to solve problems on smelter sites for a number of years, handling of concentrates, additives and metallurgical dusts. Working alongside clients around the world they have developed a number of dust handling systems for flash furnaces from New Boliden, through Codelco to PASAR. Solving handling issues in dust collection has proved to suit Schenck Process range of equipment well and now a series of solutions are available. Solutions have been developed to handle materials up to 600°C and can convey over 1 km. Conveying to remote location for disposal, injecting directly into a furnace through lances, return to furnace burner feed, or deliver and dose into leaching reactors, Schenck Process are ready to ‘make processes work’. Historic solutions at New Boliden and Codelco demonstrate a range of material application and the long term performance of the equipment. Recent installations at Pasar utilise the Schenck new ProPhaseTM equipment and handle the Waste Heat Boiler and ESP dusts directly and simplify the dust train. The paper will seek to show how this equipment can bring benefit in handling high temperature materials directly and eliminate several traditional steps that are often unreliable. The systems can be paired with Schenck Process new PHASiQTM and STREAMiQTM control systems which are complete PC, HMI, PLC, Interface system with full SCADA, Data Storage and IoT ready remote interrogation and support available. Installed in this challenging environment the systems are ready for smelter use. The systems can be also joined to our new E-nizingTM web portal. A perfect partnership to deliver the trend in ‘Big Data’ while providing visibility and off site support. The paper will show how these systems can deliver reliable equipment and remote support for these often isolated sites as well as delivering rapid return on investment. This paper discusses a step change in simplifying Flash Furnace Dust handling which Schenck believes shows the truth of Schenck Process Solutions claim that ‘we make processes work’.

Jan 1, 2019

By Andrew J. Hyett

The ISRM commission on testing methods has recently presented Suggested Methods for rock stress determination (Kim & Franklin, 1987). This proposes that even if the magnitude of in situ stress is not sufficient to cause significant ground problems, the optimum shape, orientation, and layout of underground structures can be significantly affected by it. In the design of underground excavations, the engineer often requires a knowledge of the average in situ stress tensor in the rock mass. However, attempts to measure a stress state applicable to design have proved frustrating, and a high degree of uncertainty is introduced by the variability in results. In the belief that deduced fluctuations are random in nature, many separate measurements are often made, so that a more reliable stress tensor average, and some indication of the associated variance (see Dyke et al., 1986) can be calculated. Unfortunately, this approach is limited by economic considerations and, as with any sampling procedure, it is imperative to understand the sources of measured variability, in order to design an optimum measurement programme. Cundall(1987) itemised the main causes of stress variability as a. Instrument and measurement errors, and b. Natural fluctuations of stress from point to point, induced by the action of a boundary stress on the internal rock structure. At least four categories exist: i. inhomogeneous rock, bedding, intrusions etc.; ii. differential contraction, creep, or changes in rock properties with time; iii. proximity to faults or discontinuities; iv. cycles of tectonic activity that cause movement on joints. The latter was successfully investigated using the distinct element programme UDEC. In this paper, the contribution of items (iii) and (iv) (i.e. the items related to discontinuities) to the total stress variability will be discussed, for the kind of rock mass shown in Figure 1. Although many authors have concluded that rock joints have an influence on the stress in their vicinity, a more analytical approach is required if the stress distribution associated with different jointed rock masses is to be (i) compared, and (ii) related to routinely measured joint parameters. If this can be achieved then, prior to any attempt to measure stress in a jointed rock mass, a consideration of joint geometry, joint deformability, and the geological kinematics of joints (e.g. the magnitude and direction of previous movements), can place valuable `common sense&apos; constraints on the expected stress system for minimal extra cost.

Jan 1, 1989

By Low J. R., Gensamer M., W. T. Lankford

The problem of sheet metal formability is one which has received a vast amount of attention during recent years. In spite of the great amount of study and experimental work which has been devoted to this problem, many of its fundamental aspects are still not well understood. No generally satisfactory test has been developed which is capable of providing a reasonably adequate evaluation of sheet metal formability, particularly in borderline cases. Anomalies persistently arise in which a lot of supposedly satisfactory material exhibits excessive breakage when formed. This lack of suitable technological tests greatly hinders the design of new parts and the substitution of new materials in parts of existing design, frequently necessitating considerable costly trial and error experimentation on an actual production basis. When, at the beginning of World War 11, it became apparent that mass production methods of forming would bc required in the aircraft industry if the large numbers of military aircraft needed were to be supplied, renewed attention was focussed on the problem of sheet metal formability. It was widely recognized that the formability requirements placed on sheet metals had been steadily increasing in severity through the years, especially as greater and greater emphasis was placed on streamlined designs with the resultant freer application of doubly curved surfaces. The recent advent of several new high strength aluminum alloys of more limited formability than some of the older alloys also served to emphasize the need for new approaches to the problem. It seemed evident that progress in the technology of sheet metal forming would depend to a great extent on the development of more reliable criteria for the evaluation of formability. Although the problem is admittedly very complex, the most logical approach appeared to be through studies of the fundamental material properties of sheet metals, especially under complex stress conditions simulating those prevailing in actual forming operations. Most previous investigations have failed to make full use of existing knowledge of fundamental material properties, and in many instances have attempted correlations with properties which are now recognized as being ambiguous in nature. This investigation was undertaken, therefore, with the aim of developing methods for the study of the flow and fracture of sheet meta1s under combined stresses, and of making use of such methods as might be developed in

Jan 1, 1947

By H. G. Doll

&apos;This paper discusses a method and apparatus for determining the dip of formations traversed by a drill hole, by means of electrical measurements in the hole. The process consists in recording the Spontaneous Potentials present along three oriented generatrices in the hole. By comparison of the three curves thus obtained, after application of a correction factor to compensate for any deviations of the hole, the dip angle and the dip direction are determined. Excellent accuracy is obtained for dip angles over 10°. Because the method is simp1e and the apparatus rugged, the measurements are rapid and reliable; consequently, they can be made at all the levels that are of interest at any time after the well has been drilled. Mechanical cores are not needed to evaluate the dips. A convenient, time-saving procedure is to perform the dipmeter survey at the time the electrical log is taken, using for both operations the same cable and truck. Actual examples of results obtained in wells of the Gulf Coast area are given. Introduction The problem of determining the angle and direction of the dip of the strata traversed by a drill hole has practical interest, and sometimes vital importance, which need not be emphasized to the oil industry. The need for that type of information has existed ever since wells have been drilled. Certainly it has not subsided, in spite of the numerous inventions and improvements made in other fields of the art of drill-hole exploration. The few examples given in this paper are but illustrative of this fact. In the past, methods have been devised, and used, to solve this problem, but generally they have met with limited success, possibly because they failed more or less to answer the requirements of a modern age for fast yet accurate measurements. If accurate, the results were obtained at the cost of very tedious and lengthy operations. The new S. P.* dipmeter service offered to the oil industry is the result of exhaustive and in this particular field. In 1032 a dipmeter and electromagnetic teleclinom-eter service was made available. The apparatus employed then was of a rather delicate and costly construction, and the measurements had to be made with precautions sometimes difficult to secure on the rig. Although the information given by the electromagnetic dipmeter was limited to the direction of the dip, very interesting results were obtained in California, Trinidad, Venezuela, Rumania and, most notably, in the Netherlands East Indies.+ Apparatus The S. P. dipmeter surveys present none of the drawbacks mentioned above. The apparatus is rugged and free from constructional complications, therefore well adapted to field use. This, combined with the new, basically simple approach to the problem, explains the rapidity of execution of the measurements. The results are remarkably accurate and they are complete, giving the

Jan 1, 1946

By H. G. Doll

&apos;This paper discusses a method and apparatus for determining the dip of formations traversed by a drill hole, by means of electrical measurements in the hole. The process consists in recording the Spontaneous Potentials present along three oriented generatrices in the hole. By comparison of the three curves thus obtained, after application of a correction factor to compensate for any deviations of the hole, the dip angle and the dip direction are determined. Excellent accuracy is obtained for dip angles over 10°. Because the method is simp1e and the apparatus rugged, the measurements are rapid and reliable; consequently, they can be made at all the levels that are of interest at any time after the well has been drilled. Mechanical cores are not needed to evaluate the dips. A convenient, time-saving procedure is to perform the dipmeter survey at the time the electrical log is taken, using for both operations the same cable and truck. Actual examples of results obtained in wells of the Gulf Coast area are given. Introduction The problem of determining the angle and direction of the dip of the strata traversed by a drill hole has practical interest, and sometimes vital importance, which need not be emphasized to the oil industry. The need for that type of information has existed ever since wells have been drilled. Certainly it has not subsided, in spite of the numerous inventions and improvements made in other fields of the art of drill-hole exploration. The few examples given in this paper are but illustrative of this fact. In the past, methods have been devised, and used, to solve this problem, but generally they have met with limited success, possibly because they failed more or less to answer the requirements of a modern age for fast yet accurate measurements. If accurate, the results were obtained at the cost of very tedious and lengthy operations. The new S. P.* dipmeter service offered to the oil industry is the result of exhaustive and in this particular field. In 1032 a dipmeter and electromagnetic teleclinom-eter service was made available. The apparatus employed then was of a rather delicate and costly construction, and the measurements had to be made with precautions sometimes difficult to secure on the rig. Although the information given by the electromagnetic dipmeter was limited to the direction of the dip, very interesting results were obtained in California, Trinidad, Venezuela, Rumania and, most notably, in the Netherlands East Indies.+ Apparatus The S. P. dipmeter surveys present none of the drawbacks mentioned above. The apparatus is rugged and free from constructional complications, therefore well adapted to field use. This, combined with the new, basically simple approach to the problem, explains the rapidity of execution of the measurements. The results are remarkably accurate and they are complete, giving the

Jan 1, 1946

By F. E. Harris

IT has been said that carbon is "ubiquitous" with reference to iron alloys. Certainly at temperatures where carbon and iron form the solid solution, austenite, it may be readily added to, or removed from, steel surfaces. Differences in concentration potential are the sole requirements for carbon flow. To measure the rate of carbon flow, a proportionality factor, D, is arbitrarily expressed in units of (length)2 X (time)-1. If the term used for carbon concentration is weight pct C, as is customary, then a factor must be found, changing this term to one of weight per unit volume when the diffusion coefficient, D, is used in flow formulae. The determination of D values for carbon is complicated since D varies with the concentration itself. The Matano method has often been employed for systems involving a variant D. This method expreses an evaluation of unsteady flow whereby .0 is given a relationship with the numerical value of C-X slopes. The author contends that this solution is incorrect, except when D is invariant. The primary purpose of this paper is to support this contention. Here diffusion is controlled under two conditions of flow. The first part deals with the steady state; the second part considers unsteady flow under definite restrictions. Beginning with the fundamental concept, the development is continued until equations for C-X curves are obtained. The solution is then subjected to experimental data. It is realized that a great amount of reliable data is required for a rigorous proof. No such research is claimed. Instead an attempt is made to set forth the physical significance of the diffusion mechanism, and particularly to express the factors which influence the flow of carbon in austenite. Of equal significance is the implication that gaseous media may be employed with reasonable accuracy in making these determinations. THE STEADY STATE DIFFUSION OF CARBON IN AUSTENITE The fundamental experiment defining diffusion in solid metals may be readily performed for carbon in gamma iron.1 For this experiment a thin plate of medium carbon steel is chosen. The surfaces of this plate may be taken as two parallel planes which may be considered infinite for points well in the center of the planes. These two planes are held at different concentrations of carbon at a constant temperature. This temperature, 1700°F for example, is one where the single phase, carbon in solution with gamma iron, exists. When these conditions are held for a sufficient time the concentration of carbon of the different points of the solid settles down towards its steady state value. At points well removed from the ends, the concentration will remain the same along planes parallel to the surfaces of the plate.

Jan 1, 1947

By R. D. Pehke, J. F. Elliott

The solubility of nitrogen in liquid pure iron has been measured as a function of pressure and temperature. Sieverts&apos; Law is obeyed at all pressures up to 1 atm and the temperature coefficient of solubility is 8 x 106 %/°C. The solubility of nitrogen in liquid iron alloys has been studied by the Sieverts&apos; method and by the sampling method. The solubility is decreased by Al, C, Co Cu, Ni, 0. Si atzd Sn, and it is increased by Cr, Cb, Mn, Mo, Ta, W, and V. Interaction coefficients eN, for the effect of these elements on nitrogen dissolved in liquid iron, are reported. 1 HE effect of nitrogen upon the properties of steel may be desirable or not, depending upon the composition, processing treatment, and the use of the product. To understand the behavior of nitrogen in the various steelmaking processes, it is necessary to have reliable fundamental data pertaining to the solubilities, rates of solution, and chemical reactions of nitrogen in steel, particularly in the liquid state. In an effort to extend our knowledge in these areas, an investigation of the thermodynamics and kinetics of the solubility of nitrogen in liquid iron alloys was undertaken. The thermodynamic aspects of the study are presented in this paper. The solubility of nitrogen in liquid pure iron has received the attention of several investigators whose results are summarized in Table I. Reasonable agreement among the more recent researches1-l8 is found for the solubility of approximately 0.044 wt pct at 1600°C and 1-atm pressure of N,, for the temperature coefficient of solubility being small but positive, and for adherence to Sieverts&apos; law for pressures up to 1 atm. The solubility of nitrogen in a number of binary liquid iron alloys has been studied: Fe-A1,3 Fe-As,16 Fe-C,3, 71 18, 19, 20 Fe-Cr ,5,7, 10, 11, 15 21 Fe-Co,&apos;4, &apos;6 Fe-Cu,&apos;6 Fe-Mn,10, 11, 18 Fe-Mo,13, 16 Fe-Ni,10, 11, 13, 15, 16 Fe-O,16, 17, l9 Fe-p,7 Fe-S,l6 Fe-Sb,16 Fe-Se,lg Fe-Si,4) 97 &apos;77 187 19>2° Fe-Sn,16 and Fe-v.51 &apos;3 A few ternary systems have been studied, most of which were reviewed by ~angenberg" who applied the methods suggested by WagnerPz3 Chipman,24 Darken and G~rry, and Morris and Buehl26 for predicting solubilities in multicomponent alloys. Langenberg22 and Humbert and Elliott15 compared the solubilities computed from simple binary alloy systems with experimental measurements of nitrogen solubilities in liquid iron containing two or more alloying elements. The interaction coefficients for nitrogen in

Jan 1, 1961

By John H. Bassarear

How best to grind? This article compares conventional crushing and grinding circuits to semiautogenous circuits, reviews recent installations of each circuit, and describes seven methods of using autogenous or semiautogenous techniques. In addition, steel and power consumption data are reported and benefits of a dedicated digital computer are discussed. Size reduction is the most expensive operation in most mills. Crushing and grinding are usually the greatest part of capital costs. They often make up 60-70% of total mill operating costs. Picking the proper crushing and grinding method must, therefore, be done with great care, so the best circuit is chosen. In the past 10 years, there has been a strong trend toward using autogenous or semiautogenous grinding in mills throughout the world. Autogenous grinding is favored when the ore is quite competent and a fine grind is needed. Semiautogenous grinding is applied when fine crushing could cause severe problems or when ore varies in hardness or competency. The taconite iron ores of northern Minnesota fit the description for an autogenously ground ore and many are successfully ground that way. Most im¬pressive are the nine lines of 11 x 4.9 m (36 x 16 ft) mills powered by 9 MW (12,000 hp) motors at Hibbing Taconite. Porphyry copper and molybdenum ores fit the description for semiautogenous grinding. Recent installations include Highmont in British Columbia, Canada, and Quintana in New Mexico. Sampling Many mills have been built based on inadequate sampling data or insufficient tests. With the cost of many mills exceeding several hundred million dollars, it is mandatory that geologists, mining engineers, and metallurgists work together to prepare representative testing samples. Simple, repeatable work index tests are usually sufficient for rod and ball mill tests. However, pilot plant tests on 50-100 t (55-110 tons) of ore are frequently necessary for autogenous or semiautogenous mills. Preparation and selection of the test sample is of utmost importance. Procedures for autogenous and semiautogenous mill pilot plant tests are relatively simple for those experienced in running them. Reliable and repeatable results can be obtained if simple, fundamental procedures are followed. The accompanying figure shows a typical conventional crushing-grinding circuit with three stages of crushing followed by ball mills or a rod mill-ball mill combination. This flowsheet is typical of many mills that have been built throughout the world. Also shown is a typical semiautogenous (SAG) circuit with feed coming directly from a primary crusher, and the semiautogenous mill product going to the separation process. Many similar semiautogenous circuits are built today because they are simple and flexible, lend themselves readily to high tonnages, and usually cost less to build and operate. With some ores, it is possible to send mine-run ore directly to the semiautogenous mill, eliminating the need for a primary crusher, as at Benquet&apos;s Dizon mill in the Philippines. An autogenous or semiautogenous circuit, as the name implies, uses the ore itself to assist in the grinding process. Generally, for this type of circuit, the ore must be competent so large ore chunks can be used to grind smaller ones. If ore alone is used, then the circuit is autogenous; but if balls are added to supplement the charge, then the circuit is termed semiautogenous. Ore competency is not always a criterion, to break up large pieces and wash away cementing material. Autogenous and semiautogenous mills have been very successful on relatively soft uranium ores where the values are frequently found in the material that cements together the sandstone grains. Autogenous Circuits When an ore is hard and competent, it is always possible it might make good "pebbles" that could be used for fine grinding media. Seven methods have been tried using combinations of autoge-

Jan 6, 1982

By Cleland N. Conwell

APPLICATION of seismic methods to the location of buried channels in placer mining is fairly common knowledge, yet some of the facets of seismic refraction surveys have remained obscure in their application to mining. This description by a member of the U. S. Bureau of Reclamation team investigating bedrock at the Oso Dam site, may offer a lead to wider application of the method for bedrock determinations in engineering of mine and mill plants, tailing disposal, and water supply. It may also offer assistance in planning geological exploration in areas covered by overburden. Pertinent, and perhaps more than passingly significant, is that the seismic survey of the Oso dam site started at noon and was completed the afternoon of the next day. Location Oso dam site is on the Navajo River, Archuleta, County, Colo., 30 miles southeast of Pagosa Springs, Colo., 10 miles northwest of Chama, N. M. Bedrock at the proposed dam site is Mesa Verde Formation, Cretaceous age sandstone. The nearest good sandstone exposure is about 5/8 of a mile upstream from the location of the seismic determinations. The material above bedrock is sand and gravel with sandy loam soil covering benches above the river. The site appeared favorable, after a geologic and topographic reconnaissance, but overburden thickness was unknown. Exploratory drilling was not contemplated in the near future so a short seismic investigation was selected as the most suitable method of determining depth to bedrock. Field Procedure Geophysically, a seismic depth investigation is simply the measurement of depth from ground surface to the top of a layer which transmits seismic waves at a higher velocity. In this case the high-velocity seismic layer tentatively correlates with the Mesa Verde sandstone. Field procedure required a seismic explorationline or "spread" with 12 geophones set at measured intervals. Explosive charges were buried at few feet in the ground and detonated at shotpoints near the ends of the spread, and at intermediate points. The time of travel of the seismic waves from the shotpoints through the ground to each of the geophones along the spread was measured and recorded photographically with equipment housed in a field truck. The seismograph on each spread provided a time-travel graph. From it were computed the speed of seismic waves in various layers below the surface and depth to each different seismic layer below the shotpoint. In the case of the Oso dam site it was possible, in addition, to determine the depths below certain geophones, because there were only two seismic layers involved. Interpretation In seismic exploration waves are refracted from the top of layers which often correspond to divisions between subsurface formations. When drill holes are available the geologic logs offer a means of correlating stratigraphic breaks with seismic layers, improving reliability of seismic interpretation in terms of depth to bedrock or other geologic terms. There were no drill holes available in the case of the work at the Oso dam site. Geologic conditions appeared favorable for seismic technique because of excellent contrast in seismic wave velocity between the overburden and the Mesa Verde formation. The upper layer had a velocity of approximately 2500 fps and was interpreted as overburden, the lower layer had a velocity of approximately 9000 fps and was assumed to be the sandstone. These velocities are of the order expected in these materials. The seismographs obtained at the Oso dam site were excellent. The energy from the shot came in strongly at each geophone, giving an easily read record. Time-travel graphs plotted from wave arrival times were uniform and made interpretation comparatively easy. In Spreads 1 and 2 near the river the lower velocity layer was 12 to 15 ft deep. For the spreads on higher ground, or the bench south of the river, it was from 15 to 29 ft deep.

Jan 1, 1952

By I. Bock

Selective Blast Mining (SBM) makes use of milli-second sequential blasting technology to separate the valuable reef material from waste rock in the blasting operation at stope faces in the mining of tabular ore bodies such as exist in the gold and platinum mines in South Africa. The waste rock is cast blast to the back of the stoping area, and the reef material is fractured and deposited close to the stope face. Only the reef material is transported to the surface. A simplified economic model is presented to evaluate the economic benefits of SBM. Although premature, in that adequate experimental demonstration of the validity of the model has not yet been possible, the model is presented since it indicates substantial benefits in the case of narrow reef gold mines. It is suggested that many marginal mines should seriously consider SBM. Benefits can also be realised in platinum mines, but a lot more experimental work is necessary to establish cost parameters more reliably. Some practical experience in the use of SBM in the mining of the UG2 reef is presented.

Jan 1, 1998

By R. E. Hobart

THE development of the Hauto power plant and the claims made by various engineers that electricity was more economical than steam for power purposes in and about the mines; led the Lehigh Coal and Navigation Co., in 1911, to conduct a test to ascertain the consumption of power used by a large steam hoisting engine. The question being one on which no reliable information could be found, and the opinion of various engineers differing to such an extent, it was decided that a test under actual operating conditions was necessary. This was arranged for at one of the collieries. The engine selected was a 30 by 60-in. (76.2 by 152.4-cm.) piston-valve engine of modern type, and comparatively new. The boiler plant from which the hoist received its power was about 600 ft. (182 m.) from the engine, the latter being fed by a 10-in. (25.4-cm.) steam line insulated with magnesia pipe covering. Two batteries of the boiler plant, aggregating 1200 hp., were cut off and fed into a separate steam line leading direct to the hoist engine. Steam auxiliaries, consisting of feed-water pump and blowers, were fed by the boilers in test, and their consumption charged against the hoist. A barrel weighing device was installed, as it was felt that this would be the most accurate way of determining the consumption of water. The fuel, No. 3 buckwheat, was carefully weighed, and every precaution was taken to make the test accurate in every particular. The test was run for 1 week, or a total of 168 hr. A record was kept of the number of trips hoisted or lowered, and continuous indicator cards were taken. One particular set of cards was taken with the hoist operating balanced, and also with the hoist operating with no counterweight other than the empty cage, the coal in the car being weighed. The speed of the hoist was taken by means, of a graphic recording instrument which registered the number of revolutions every 5 sec. From this record, speed-time curves were plotted.

Jan 2, 1918

By R. P. Alger, J. S. Wahl, C. W. Johnstone, J. Tittman

To overcome the problems of mudcake and hole irregularities, the new compensated formation density logging device employs two detectors spaced at different intervals from the source. The detector at the shorter spacing is particularly sensitive to the density of material immediately adjacent to the face of the pad. The contribution of this material, which includes mudcake and minor wall irregularities, affects the response of each detector to a different degree. The signals from both detectors are combined to give automatically a density correction which is added to the uncompensated density information from the detector at the longer spacing. Both the compensated density measurement and the amount of compensation are then recorded on the log. With the unwanted borehole effects removed, the measurement is recorded directly in terms of bulk density on a linear scale. INTRODUCTION Formation density is a very useful and diagnostic parameter for formation evaluation. When the matrix lithology is known, porosity is accurately and readily computed from density data.&apos;-" hen the density measurements are used with other porosity-responsive measurements, such as Sonic and Neutron logs, both lithology and porosity may be defined with good accuracy."&apos;" In the past, however, application of density logs was complicated by the need for corrections to obtain true formation densities from the log values. Mudcakes on permeable formations and roughness of the borehole walls have been particularly troublesome since, in each case, the device was prevented from direct contact with the formation. ~ttempts have been made to correct for such conditions by making a simultaneous caliper log, estimating pad standoff, and assuming knowledge of the composition of the intervening materials. While such corrections are frequently accurate, they are not always reliable because of uncertainties in the pad standoff and material composition. A further complication was the necessity for manual conversion of log counting rates to density. The newly introduced compensated formation density logging device (FDC) automatically corrects for mudcake and minor wall irregularities, and provides a log that is scaled directly in bulk density. The purpose of this paper is to discuss briefly the equipment, to explain the theoretical considerations involved in the compensation, and to present field examples of this new log. COMPENSATED FORMATION DENSITY EQUIPMENT The FDC tool incorporates two major advances over previous density logging devices: a second detector, spaced closer to the gamma ray source to provide increased sensitivity to material close to the pad; and the automatic derivation of a corrected formation density from the two counting rates. The arrangement of the source and detectors is shown in Fig. 1. The longer spacing detector is at the same spacing from the source and gives the same response as the single detector in the previous uncompensated device. By appropriate combination of the outputs of the two detectors, the FDC tool is able to compensate in large measure for effects of mudcake and hole rugosity. This is achieved, as will be described later, without specific knowledge of either the thickness or the nature of material between the pad and formation. To obtain corrected formation density, the two count rates are automatically processed by an analog computer in the surface panel. More specifically, the computer derives a value of uncompensated formation density from the long-spacing counting rate, computes a density correction p using both the long and the short spacing count-

Jan 1, 1965

By J. S. Lasater

Resu1ts of experinmental measurernents of heat capacities and thermal conductivities of some typical porous rocks are presented. Measured heat capacities agree closely with va1ues calculated front known chenlical . compositions of the rocks. On the basis of this agreement, heat capacitir.7 of fluid-satttrated rocks were calc~ililted. Therrnal conductivities of the rock samples were measured under varioits conditions of fluid saturation. From these data therrnal dif-fvsivities were calculated. A significant variation of thermal diflusivity with trnlperature is indicated. Knowledge of the thermal characteristics of fluid-bearing porous rocks has become increasingly important with the development of thermal oil-recovery processes. Reliable thermal data for petroleum reservoir rocks are not available and approximate values are generally assumed for reservoir calculations. &apos;The effects of temperature, pressure and fluid saturation on thermal properties of porous rocks have not been carefully studied. The purpose of the present work was to measure and report the thermal characteristics of some typical porous rocks. A group of eight sedimentary rock samples, including limestone, shale, sandstone and silt-stone, was selected for the study. Properties reported include heat capacities, thermal conductivities and thermal diffusivities. The effect of fluid saturation on these properties was also considered. Determinations of thermal properties require precise measurements which are time consuming and difficult to reduce to a routine basis. Methods have not been developed for measurement of thermal proper-ties under conditions of pressure, temperature, and fluid saturation, which may be encountered in thermal recovery processes. As one approach to these problems, some preliminary work on methods of estimating thermal properties from other more readily measurable characteristics of the rock-fluid system is reported. The samples selected for the studies were oilfield cores from within, or closely associated with oil-productive zones. Descriptions of individual samples are given in Table 1. Clay minerals present in the samples were determined by differential thermal analysis (DTA). Quartz content was estimated from DTA cooling curves. For all but the thermal conductivity tests, a representative 200-gm sample of each core was disaggregated, thoroughly extracted in diox-ane and oven dried at 100°C. The cleaned and dried sample was care- fully split into appropriate portions for the several tests. Chemical analyses of the samples were obtained to permit calculations of heat capacities by methods which are outlined later. Resuits of chenlical analyses are given in Table 2. Heat contents of the test samples were measured by a Runsen-type calorimeter. The heat content of the unknown sample is measured relative to the known heat content of platinum. The apparatus is referred to as a relative error type because of the comparative measurements, and has the advantage of canceling systematic errors. Experimental results are reproducible within 0.5 per cent. A temperature base of 298.16 K is taken for heat content measurements. Measurements were made at five temperatures (260, 440, 620, 800 and 980° F). It was necessary to preheal the sample above the maximum experimental temperature to eliminate volatile constituents. Assuming the weight loss on pre-heat, ing was mostly water, a correction to the observed heat content was made to account for the water originally present in the sample. This latter procedure was followed in the determination of calculated heat contents as will be described later. The apparatus and the method of measure-

By L. D. Wooddy, W D. Moore

Water drives may be natural or artificial. For the case of a natural water-drive reservoir, the volume of water influx corresponding to reservoir pressuve-production history may be calculated by means of the material bal-ance-unsteady state equation. For the artificial water drive or pattern injection water flood, the material balance equation is sufficient to determine the reservoir pressure-production, injection history. However, for both cases to reliably predict reservoir performance, it is necessary to calculate the saturation distribution of the reservoir fluids at different stages of depletion. This paper consolidates the various equations used to determine the performance of water-drive reservoirs into one approach that is applicable to any reservoir that has a natural water drive or is to be produced by water injection. The numerical procedure has been simplified considerably, and the solution is adaptable to either hand calculations or digital computer operation. INTRODUCTION A water-drive reservoir is one in which the predominant source of energy for production of oil results from the encroachment of water into the oil zone. The water drive may be either natural or artificial. Water invasion takes place by expansion of water in the aquifer as a result of the pressure decline transmitted from the oil reservoir. Because water is practically incompressible, a natural water drive requires an extensive aquifer containing a volume of water many times the volume of oil in the reservoir. Provided the permeability of the formation is reasonably high, a moderate decline of reservoir pressure usually causes adequate water influx. If the reservoir pressure decline becomes excessive because of low permeability or a high rate of production, part of the oil production may result from the liberation of dissolved gas which may cause excessive quantities of free gas to be produced along with the oil. In extreme cases, reservoir pressure may decline so rapidly as to cause the oil to be produced predominantly by dissolved gas drive, leading to abandonment of the reservoir before the advancing water has had a chance to flush the entire reservoir. In reservoirs that are not connected to extensive aquifers, an artificial water drive may be created by injecting water into or around the lower edges of a reservoir. Sometimes water is injected within the reservoir through wells interspersed among the producing wells. When injection is carried out in such fashion, the reservoir is in effect subdivided into a number of separate producing segments, in each of which the displacement of oil is simultaneously taking place, and the shapes of which are fixed by the well patterns employed. Because of the natural tendency of oil and water to segregate according to their relative densities, water will tend to migrate downdip regardless of where injected. Accordingly, the injected fluids can be retained within the intended reservoir segments only when conditions are unfavorable to their migration under the force of gravity. Pattern injections are usually confined, therefore, to reservoirs having low structural relief, or low permeability, or when production and injection rates are such that fluid movements in the reservoir are dominated by the pressure gradients rather than by the force of gravity. In the case of natural water-drive reservoirs and artificial water-drive reservoirs in which the water is in-

Jan 1, 1958

By J. Kucera, J. Vreštál

DIFFERENT authors1 &apos; have been engaged in meas-uring the vapor pressure of pure cobalt. The results of their measurements satisfy the expected temperature dependence of vapor pressure and are in mutual agreement, with the exception of the results by De Dyk Man and ~esmejanov.~ The latter authors, by using the effusion method, have achieved considerably higher values than other workers. By using the isotope exchange method they obtained much lower values than other authors. The determination of thermodynamic functions of the binary Ni-Co system was carried out, as far as we know, only by De Dyk Man and Nesmejanov.4 This determination was based on extremely low values of vapor pressure over pure cobalt obtained by the isotope exchange method. Therefore we considered it useful to repeat these measurements. Furthermore, the reliable values of thermodynamic functions should complement the migration characteristics, the inner magnetic field data obtained by Miissbauer effect measurements, specific heat data, and the K effect and positron annihilation characteristics that have been achieved for the Ni-Co system in the Institute of Metallurgy of the Czechoslovak Academy of Sciences in Brno.5-9 The measurements in this paper were performed by the isotope exchange method. In this method, as has been shown by analysis,10-&apos;3 the vaporization rate, w, can be calculated from the relation w = k/1oSw [1] i0Sw) [1] where L, is the activity per unit mass of the source, S is the area of evaporation, k is the tangent at the point t = 0 to the curve giving the radioactivity de-pendence of the target vs annealing time, t, and wis the probability for the tracer atom condensation on the target surface. The value for cc. can be obtained from the equation w = a + 2P(l-a) [2] where P is Clausing&apos;s coefficient and a is the condensation coefficient. In the present work the cylinder shaped containers for annealing the samples were used, characterized by the ratio 1:d = 1.06. Here 1 is the length and d the diameter of the container. For this ratio P = 0.514 and w =0.5, and w is independent of the condensation coefficient. The vaporization rate is related to the vapor pressure p by the relation where R is the gas constant, T is the absolute temperature, and M is the molecular weight of the component investigated. Measurements of the vapor pressure of the i component over the pure metal, p!, and the alloy, pi, at the given temperature and composition enable one to calculate the thermodynamic activity of this component from the equation ai=pi/pi [4] is and the activity coefficient ri=ai/xi [5] xi where xi is the molar fraction of the investigated alloy component. EXPERIMENTAL Evaporization rate measurements were carried out with pure cobalt and eight different Ni-Co alloys, which were kindly delivered by the Centre National de Recherches Me&apos;tallurgiques Liege, Belgium. The composition of the alloys is given in Table I. The cobalt used in these alloys contained the following impurities: 0.016 wt pct Fe, 0.014 wt pct Cu, 0.01 wt pct Mn. Other elements were present in much lower concentrations. From the melts, samples in the form of small cylinders of 12 mm in diam were ma-chined. The thickness of the targets and sources was 2.5 and 1.2 mm, respectively. The lower thickness of the sources was chosen to make their over-all ac-tivity as low as possible. Sources were activated in

Jan 1, 1970

By Carlos G. Valenzuela

The value generally accepted for stacking-fault energy, of copper has been approximately 40 ergs per sq cm based on Fullman&apos;s2 value for the coherent twin-boundary energy and the assumption that is twice the twin boundary energy However, Thornton and coworkers8 determined that the lower limit of for copper is approximately 60 ergs per sq cm, based on measurements of dislocation-node radii. They suggested that the assumption of = 2t is invalid. It is the purpose of this note to present results which indicate that the values of obtained by measurement of twin-grain boundary intersections and the values obtained by measurement of dislocation-node radii are actually compatible. The most reliable values for of the a brasses, based on electron-microscope observation of dislocation nodes, are probably those values reported by Smallman and Green6 who applied the Siems correction (1961) to data obtained by Howie and Swann.3 These values shown in Fig. 1 give an extrapolated value of approximately 70 ergs per sq cm for pure copper. In the present work, Fullman&apos;s method for determining the stacking-fault energy of copper was extended to the a brasses. High-purity copper (99.999 pet) and high-purity zinc (99.999 pet) were mixed in proportioned amounts and melted in sealed and evacuated quartz tubes. The alloys were homogenized for a week at 750°C and chemically analyzed by means of X-ray fluorescence. These alloys, along with a specimen of pure copper, were rolled to 98 pet reduction and a thickness of 0.009 in., resealed, and annealed for 40 hr at 715°C. Values for the ratio of twin-boundary energy to the grain-boundary energy, it gb, were obtained from measurements of dihedral angles formed at the intersections of twin boundaries and grain boundaries by using Fullman&apos;s2 mechanical analogy of surface tensions acting at the intersection of an annealing twin and a grain boundary. The angles between the twin traces and the grain boundaries were measured for a large number of twin-grain boundary intersections at a magnification of X500 using a rotating mechanical stage on a Reichert metallograph. The rotary stage has a calibrated angle scale with vernier so that measurements can be made to 0.1 deg. The mean twin-grain boundary energy and standard deviation were calculated for copper and each of the brasses by the use of an IBM 7072 computer. It was found that the mean value of gb stabilized after approximately 100 twin-angle measurements. This was determined by plotting the mean against the number of angles measured. Since the measured angles deviate from true dihedral angles, a correction factor for grain orientation, discussed below, was applied. The stacking-fault energy was then calculated from these values and the values of grain-boundary energy derived by Taylor.7 The data obtained are tabulated in Table I. Values for stacking-fault energy are plotted in Fig. 1. The value of gb for the specimen of 1.03 pet Zn is close to the value obtained by Fullman2 for OFHC (99.98 pet) copper, 0.045. It is believed that the purity of the copper affects gb significantly. The 99.999 pet purity Cu used in this investigation yielded a value of yt/ygb, 0.76, which is much higher than that obtained by Fullman. Additional evidence suggesting that the purity of

Jan 1, 1965