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By Meguru Nagamori

DURING the smelting of the sulfide ores of copper, nickel, and certain other metals, a matte phase is formed. For a better understanding of the physico-chemical properties of mattes, binary systems such as Cu-S, Ni-S, Fe-S, and so forth, should be studied, especially in the vicinity of liquid compounds such as Cu2S, Ni3S2, FeS, and so forth. These compounds are relatively stable in the solid state although they can exhibit appreciable deviations from stoichiometry. With small deviations from stoichiometry there are large changes in the activity of both sulfur and metal this is a characteristic of both solid and liquid sul-fides near the stoichiometric compositions. In the vicinityof molten Cu2S,1 for instance, the activity of sulfur increases about 100 times for a 0.012 increase in the mole fraction of sulfur and, correspondingly, the activity of copper decreases greatly. In this sens the minor deviations from stoichiometry should be carefully taken into account in studies of such metal-sulfur melts. Metal-sulfur melts may be considered to have properties intermediate between metallic solutions and molten salts, i.e., neither entirely metallic nor entirely ionic. The radius of the ion sZ- is 1.84 as compared with 1.04? for a single bond covalent s.2 It is therefore inferred that when the sulfur is more ionic its partial molar volume is larger, although metal-metal, metal-sulfur, and sulfur-sulfur interactions may bring about further complexities. Thus, it is to be expected that the molar volumes, which are derived from density-composition relations, will help in resolving the structure of the melts. In this study the maximum bubble pressure method with bubbling gases of H2, H2S, and Ar, .was employed to measure the density. EXPERIMENTAL Materials. Silver of 99.95 pct purity was melted in an alumina crucible and hydrogen gas was then bubbled through the liquid for the deoxidation. In preparation of Cu2S, electrolytic copper powder (>99.9 pct Cu) was mixed with precipitated sulfur and heated to 1200°C in an alumina crucible under a hydrogen atmosphere. Mixtures having the approximate compositions FeS and Ni3S2 were prepared by heating reagent grade electrolytic iron or reduced nickel powder with precipitated sulfur under a hydrogen atmosphere. The H2S gas was of 98.5 pct purity, the impurities being mostly CO2 and CS2 which hardly contaminate the melts. Apparatus. The crucible system is shown schematically in Fig. 1. To minimize the variation of melt composition during a density measurement, the apparatus was designed in such a way that either Ar, H2, H2S, or mixtures of these gases could be used as the bubbling gas. When the melt had a high partial pressure of sulfur, H2S gas was used. When the partial pressure of sulfur was so low that oxygen might dissolve in the melt, the use of H2 was preferred. In intermediate cases, argon or mixtures of H2-H2S were used. Density of Dibutylphtalate. Dibutylphtalate was used as the manometer fluid. Relative to distilled water, the density of the dibutylphtalate, pdib g per cc, was measured and found to be: pdib (25°C) = 1.046 i 0.002. With the use of the temperature coefficient reported by Kemppinen and Gokcen,3 the following value was

Jan 1, 1970

By Keros Cartwright

Sanitary landfilling has become one of the most widely used methods of disposing of solid refuse. A principal concern of regulatory agencies and the public itself is that landfill operations do not degrade the physical environment, including water resources, and the ground-water reservoir in particular. Ground-water and engineering geology can guide landfill operations into suitable terranes or develop measures to compensate for any natural limitations at a particular site Experience and research in Illinois suggest four activities relating to landfill disposal that warrant attention by geologists and engineers: (1) Regional delineation of favorable and unfavorable hydrogeologic conditions to facilitate planning and preliminary screening of potential landfill sites. (2) Site evaluations, with considerations of geologic materials, topography, water levels, flow systems, and local occurrence and use of water resources. (3) Re- search on aspects of the hydrogeologic environment that control effects of, or are modified by, landfills. (4) Formulation of practices in the siting, construction, and operation of landfills that prevent, mitigate, or isolate deleterious effects. The first two activities are basically in the domain of earth science, requiring the application of fundamental concepts of geology and hydrology and conventional site-exploration methods. The third activity, research, requires contributions from geology as well as other disciplines, including soil physics, sanitary engineering, and chemistry. The fourth calls for policy decisions by regulatory agencies and elected officials, using the contributions of scientists and engineers.

Jan 1, 1970

By R. K. Govila, E. H. Parkison

THE interplanar angles for hcp metals vary with c/a ratio, and therefore must be computed separately for each particular metal or alloy. Manual computation of these angles is laborious and time consuming, and for this reason computer programs have been developed to accomplish this task.1"3 However, these programs have certain disadvantages. For example, they require prior knowledge and understanding of ALGOL or FORTRAN languages. Further, they will not print out specific angles but instead give all angles between given limits—thus program2 prints out a total of 26,649 angles between planes with indices and in the range from (4 4 4) to (4 4 4) for any given c/a ratio. The purpose of this note is to present a simple and inexpensive computer program for accomplishing this task. This program is written in BASIC language4 which does not require any prior knowledge of computer programming, and is ideally suited for nonprofessional programmers. It also provides flexibility for the user by allowing him to select any indices for as many or few planes as desired for any given c/a ratio. The computer program proposed below is based on the relationship in which + is the angle between any two planes and . TO illustrate use of the program, consider the problem of calculating the interplanar an-

Jan 1, 1970

By P. W. Jeran

The Stereonet Analysis Program (SNAP) is a mathematics tool which, by means of a computer, reproduces mathematically the manual techniques of pre- paring stereograms. This computer program was developed to provide a fast, accurate, and economical means of analyzing fracture orientation data. It is mitten in FORTRAN IV for use on a UNIVAC 1108 operating under an Exec II system, but can be adapted to other systems. SNAP is currently being used to aid in the analysis of cleats and other geologically induced fractures associated with coalbeds that are being mined underground, Methane flows through the coalbed and into these mine workings predominantly through the fracture system. Therefore, knowledge of fracture orientation is an invaluable aid in the development of methane control technology.

Jan 1, 1970

By H. P. Dibbs

An account is given of the application of neutron activation analysis to the rapid, non-destructive determination of copper in minerals, using a 14-MeV neutron source. Elements that interfere in the determination of copper by this method are given, together with the errors in the estimation of copper that result from the presence of varying amounts of these elements. The possible use of a compact "sealed-tube" 14-MeV neutron generator for the field assay of copper in minerals is discussed.

Jan 1, 1970

By E. H. Herron, J. H. Perry

Mathematical simulation of reservoir behavior may be used to help understand reservoir processes and to predict reservoir behavior, thereby leading to the most economically desirable form of exploitation. In addition, simulation can be used as a tool for reservoir description to learn more about the physical nature of the reservoir and the mode of primary recovery. This use is essential in most reservoir studies and represents one of the more significant applications of simulation. Prediction of reservoir behavior provides information concerning displacement efficiency, optimum well locations, and the comparison of alternative producing processes. Since oil, water and gas all commonly occur in many reservoirs, a simulation that takes into account the simultaneous flow of three immiscible phases is a prerequisite for obtaining such information. Furthermore, a simulation that describes this flow in two dimensions provides the capability of evaluating combination gas- and water-drive reservoirs with either an areal or a cross-sectional description. Many reservoir problems require such a simulation. The objective of the research described here was to develop a mathematical model and associated computer program for accurate, efficient, and economical prediction of the reservoir flow of three phases in two-dimensional geometry. Several authors have discussed multidimensional reservoir simulation of two phases.l-3 Gottfried et al.' presented an analy- sis of three-phase simulation in one dimension. Fagin and Stewart" and Garrett6 have discussed the simulation of three-phase flow in two dimensions, but their solution techniques were different from the method discussed in this paper. In particular, previous models and computer programs have usually involved either fewer capabilities or inefficient and less rigorous descriptions resulting in limited applicability. In the following sections, we present a description of the model, an evaluation of the method, and the application to reservoir problems. Additional and supporting material is presented in the Appendix. The Three-Phase Model General Description The three-phase model consists of the mathematical description of the flow of oil, water and gas in a reservoir. Conceptually this description considers flow in all three space dimensions, but in the subject simulator it is assumed that no flow occurs in the third dimension. The model includes the effects on reservoir behavior of fluid and rock compressibility, viscosity, gravity, capillary pressure, relative permeability and gas solubility. Within the two-dimensional restriction, the reservoir considered may be completely heterogeneous and anisotropic. The differential equations governing multiphase, multidimensional flow in a reservoir are too complex to be solved analytically, so they are approximated by a system of finite difference equations and solved

Jan 1, 1970

By Lester J. Crow

This study advances the use of elemental sulfur in structural materials by demonstrating its value in bonding high-strength, well-graded basalt aggregates to form sulfur-basalt concretes. Sulfur is an excellent bonding agent, and the strength of a thermoplastic sulfur-aggregate mixture depends, to a large degree, on the strength and grain-size distribution of the aggregate used. A 3-cubic-foot, electrically powered mixer with heat applied to the barrel was used to mix the sulfur and aggregate. Sulfur content of several mixtures was varied to obtain the best workability with a minimum of sulfur in excess of that necessary to fill the voids. The average grain sizes and grain-size distributions were also varied to determine their effects on strength. Unconfined compression tests of forty-five 6-by l2-inch cylinders yielded average strendths of 3,348 psi to 10,398 psi. The highest strength single cylinder was 10,717 psi. The cylinders were tested from 24 hours to 6 days after pouring; after 24 hours the rise in strength was very slight. From the results obtained it appears that sulfur can be a useful construction material. An evaluation was made of a high-vacuum application for sulfur concrete. Sulfur has a high vapor pressure at elevated temperatures, 50° to 100° C; consequently, significant losses by sublimation can be expected. At lower temperatures the losses are not significant; however, this factor will limit its use at a higher temperature.

Jan 1, 1970

By Frank M. Randall

The Buick mill is located at the site of the old Buick general store, approximately 4 miles south of Bixby, Missouri on route KK. It is a part of the operations in the area now called the "New Lead Belt". The ore body lies at an elevation of 270 feet above sea level, and is fairly flat lying, becoming slightly deeper toward the south. The mineralization is due to the secondary deposition of galena, sphalerite, chalcopyrite, pyrite, calcite, dolomite and some localized drusy quartz in a country rock of dolomitic limestone. The galena is fairly coarse grained with some large crystaline structure, and some oxidized surfaces. The sphalerite is fine grained- small crystals containing Cd (about 0.7%) and Ag (about 10 oz per ton) in solid solution. The chalcopyrite is fine grained, fine crystals that are sometimes massive in nature. The mine plan is a modified room and pillar system. Broken ore at the mine face will be transported to several different ore passes by rubber tired load-haul-dump units. Ore passes will drop the ore to a rail haulage level some 90 feet below the mining level where bottom dump cars will deliver it to a 42 in. Nordberg gyratory crusher. Two 12 ton capacity skips in balance carry the ore some 1,200 feet to the surface. The hoist is equipped with automatic controls for loading, hoisting and unloading.

Jan 1, 1970

By C. W. Kovach, A. Moskowitz

Studies were undertaken to investigate the effects of manganese content on the machinability and other Properties of a free machining martensitic stainless steel (AISI Type 416). Machinability was found to be significantly improved in steels of high manganese content, and a direct relationship was obtained between machinability and steel Mn:S ratio. As the manganese content of the steel increases, the sulfide Phase present changes from CrS to (FeMn)Cr2S4 to (MnFeCr)S, and finally to MnS. The average sulfide inclusion hardness decreases through the same range of increasing manganese content. The mechanism for machinability improvement is discussed in terms of a soft ductile sulfide affecting deformation in the secondary shear zone. Type 416 containing relatively high manganese for improved machinability shows good general properties. The effects of increasing manganese content on mechanical properties, cold formability, and corrosion resistance are described. THE addition of sulfur is commonly used to improve the machinability of stainless steels. However, little attention has been paid in the past to the composition and characteristics of the sulfur-containing phase or phases present in these resulfurized steels. Recent information on the properties of sulfide phases, and their role in metal cutting, suggests that variations in these phases could have critical effects on machin-ability, as well as important effects on formability and other properties such as corrosion resistance. Manganese, chromium, and iron are strong sulfide forming elements present in stainless steels! of these, manganese has the greatest sulfide forming tendency and iron the least.1"1 The manganese content of resul-furized 13 pct Cr steels, often about 0.5 pct, can be insufficient or only barely sufficient to combine with the sulfur that is present; thus, the precise level of manganese can strongly influence the nature of the sulfide phase. Sulfide phases which may be present in stainless steels have been reported to include CrS, a spinel-type sulfide, chromium-rich manganese sul-fide, and manganese Sulfide.5,6 Detailed phase relationships for the Fel3Cr-Mn-S system have been reported by the present investigators,7 and a portion of this work will be referred to subsequently in this paper. Recent work by Kiessling6 and Chao et a1.8 has shown that sulfide phases can display wide variations in hardness, and may undergo considerable plastic deformation under isostatic loading.9-12 Early theories of metal cutting attributed the influence of sulfur to a lubricating effect. It is now apparent that the influence of the nonmetallic inclusions and their properties on crack initiation, deformation in the shear zones, and boundary films must also be considered in relation to the machining process. This paper presents the results of studies conducted to relate machinability to the various sulfide phases which occur in stainless steels. This work has led to the development of alloys with improved machinability, and has generated information on the effects of inclusions on metal cutting processes. Effects of sulfide inclusions and steel composition on other important metallurgical properties are also discussed. MATERIALS For drill machinability and inclusion studies, 10 lb laboratory heats were melted in an air induction furnace. These heats were made with sulfur contents be tween 0.10 and 0.50 pct and manganese contents be tween 0.05 and 3.0 pct. Residual elements were added to the heats in amounts typical for commercial steels. The typical compositional range covered by the heats is shown below: C Mn P S Si Ni Cr Mo Cu N 0.10 0.05 0.007 (M0 0.40 0.40 13.0 0.20 0.10 0.03 3.0 0750 The laboratory ingots were forged in the temperature range of 1800" to 2100°F to 3/4-in. sq bars, and all bars tempered to a hardness aim of 200 Bhn prior to testing. Because of differences in composition and tempering response, the tempered bars showed some variation in hardness (175 to 275 Bhn) as well as variations in delta ferrite content (0 to 50 pct). Composition, hardness, and delta ferrite content were considered in the analysis of the machinability data. Additional tests involving tool-life evaluation and determination of other properties were conducted on materials from commercially melted and processed 15-ton electric furnace heats. TESTS AND PROCEDURES Machinability of the laboratory heats was evaluated in a drill test. In this test, 1/4-in. diam holes, 0.4 in. deep, were drilled alternately in a test bar and in a standard bar for a total of four holes in each. This sequence was repeated three times using a freshly sharpened drill each time. The average time required to drill a hole in the test bar was compared to that for the standard bar. A drill machinability rating was assigned to the test bar relative to a rating of 100

Jan 1, 1970

By T. H. Patching

This paper provides a review of the available information on the origin and mechanisms of the release of gas from coal seams. With the opening up of new mines in Western Canada and the increased mechanization of underground coal mines, the study of gas emissions is of increasing importance in providing safe working places underground.

Jan 1, 1970

By John J. Stetler

The Companhia Vale do Rio Doce in Brazil operates one of the most extensive systems in the world for the mining, transportation, processing, pelletizing and shipping of high grade hematite iron ore and pellets. Current shipping of unbeneficiated, sized, high grade ore from its ports at Tubarão and Vitória is now at the rate of 17,500,000 metric tons annually. An increase in this annual rate is now under study. Using the technology and facilities of Lurgi (1) and Arthur G. McKee company CVRD undertook a program to process and pelletize two types of fines - "Blue Dust" and ?Itabira Fines?. Blue Dust is a high grade fine ore which was bypassed while mining the direct shipping ores and which, also, exists as a very large ore body called the Conceição Mine. Itabira Fines is a lower grade of fine ore which is comprised of in-situ fines and, also fines which are generated in sizing the direct shipping ores for a rigid specification market.

Jan 1, 1970

A portable electronic instrument was developed which will measure change of longitudinal wave velocity with change of uniaxial stress in rock columns. The instrument is a solid-state device powered by nickel-cadmium batteries. It uses a probe of two piezo-electric crystals spaced inches apart to send and receive a pulse through a stressed rock. A one-inch cathode ray oscilloscope visually displays the longitudinal wave. A reference chart is used to find the stress. Laboratory results have indicated that the average stress on a sandstone column can be found to within 35 psi. The feasibility of using this instrument to determine stresses in mine pillars is to be studied. The instrument may be used to investigate physical properties of rock.

Jan 1, 1970

By C. H. P. Lupis, Henri Gaye

There are m -I conditions for the stability of a solution of m components with respect to infinitesinzal flucturations. However, in most cases, only one of these conditions has to be considered to determine the domain of instability and the existence of this more restrictive condition greatly simplifies the calculations. It may be used advantageously for the prediction of miscibility gaps and the method is illustrated in details for the case of the Ag-Pb-Zn system. THE thermodynamic conditions for the formation of a miscibility gap may be viewed as a necessary consequence of the conditions for spinodal decomposition. A previous article1 has examined in detail the form of these conditions for multicomponent systems. There is only one condition for the stability of a binary system (with respect to infinitesimal fluctuations), but there are two conditions for a ternary system, and m — 1 conditions for an m-component system. The probability of violating a stability condition, and thus forming a miscibility gap, obviously increases with the number of components, a result which is rather intuitive since the atoms of the solution have now many more ways of redistributing themselves and introducing complexities in the form of the free energy hy-persurface. It is of interest to take advantage of this possibility of precipitating new phases and to examine which stability condition is the likeliest to be violated, that is, which stability condition is thermodynamically the most restrictive. The finding of such a condition would greatly simplify the application of the stability criteria since only one condition could then be considered, instead of m - 1. In Ref. 1, coherency strain energy terms were neglected, thus restricting the applications of the treatment to solutions where they are negligible, such as liquid alloys. In the following study the same assumption will be made. To generalize the treatment to systems where the strain energy terms are sizable, the reader is referred to Cahn's classical article on spinodal decomposition.2 Let us designate by Gij the second derivative of the Gibbs free energy with respect to the number of moles ni and n j. There are several equivalent sets of m — 1 stability conditions.' The one considered here expresses that the successive diagonal determinants of order 1, 2, ... m — 1, associated with the symmetric Gij matrix (for 2 5 i, j 5 m) are positive.' For a binary solution 1-2, the condition for stability is: O(u=G22^0 [1] For a ternary system 1-2-3, the condition [I.] is re- tained (the value of G22 will differ, of course, according to the concentration of 3) and another condition is introduced: £>(21 = G22G33 - Gl3 ^ 0 [2] In a composition diagram, these two conditions define two domains of instability. Starting at a point where the solution is stable (for instance at a point where the solution is very dilute) we gradually change the composition until the condition [I] or [2] is violated. As already noted in the literature, e.g., in the work of Prigogine and Defay,3 it is the boundary of the domain (2) which is first crossed. For if we assume that the boundary of the domain (1) is reached first, at this point G22 = 0 and the second condition is necessarily violated (D(2) = -& 5 0), in contradiction with our original assumption. An exhaustive study of the ternary regular solution case may be found in the work of Meijering.4 Moreover if the boundaries of the two domains have a common point, they also have a common tangent. For if the two lines were to cross each other as is illustrated in Fig. 1(a) any point M in the line QP would be such that £> = 0 and 0"' > 0 which, as shown above, are incompatible results. Thus, the two lines must be tangent at their common point Q as illustrated in the example of Fig. l(b). The reasoning of Fig. l(a) implies that the point Q is not a "singular" point for either boundary line. This singularity may be of two types. First, the lines meet without crossing each other and without being tangent. Second, the tangent at Q for D"' or 0"' is not single-valued. Other types of singularity are unlikely because of the usual analytical forms of D"' and 0"'. The exception to the common tangent requirement due to the first type of singularity was pointed out by John Morral;5 it occurs when the common point, Q' or (3" in Fig. l(b), is located at a boundary of the composition diagram, e.g., at the line X3 = 0. It may also be noted that at the common nonsingular point Q of D(1) and D(2), Fig. 1(b), G23 is necessarily equal to zero, whereas at a point such as Q' or Q", this conclusion is no longer valid because the product G22G33 is now indefinite (of the form 0. a). The exception to the common tangent requirement due to the second type of singularity occurs when two branches of the same boundary line intersect, for example when D(1)or D(2) decomposes into a product of functions, at a point which belongs to the boundary of the other condition. It is possible to show by a simple analytical calculation that, in this case, if Q is a singular point of D(1), then it is necessarily a singular point of D(2), and that the reciprocal is true except if G33 = 0 at Q. For the present article, however, more elaboration on these singularities appears to be unwarranted. To generalize the previous results to an m -component system, we use the mathematical theorem stating that if the diagonal determinant D(r) = 0, then

Jan 1, 1970

By R. Kossowsky, W. C. Johnston

CONSIDERABLE experimental data has been published in recent years on a few directionally solidified aluminum base eutectic alloys. The mechanical properties of A1-Al3Ni eutectic have been studied by Lemkey, Hertzberg, and Ford1',2 and Salkind et a1.3 where the alloy has been demonstrated to behave as a whisker reinforced composite with superior properties over many aluminum alloys. It has also been shown4 that aluminum reinforced with Al3Ni whiskers R. KOSSOWSKY, Member AIME, is Senior Metallurgist, Westing-house Research Laboratories, Pittsburgh, Pa. W. C. JOHNSTON, formerly with Westinghouse Research Laboratories, is Head, Department of Physics, George Mason College, University of Virginia, Fairfax, Va. Manuscript submitted March 28. 1969. IMD__________________ possesses excellent microstructural stability to 508°C. The effect of lamellar structure in A1-CuA12 eutectic was compared3 to the rod-like structure in the A1-Al3Ni eutectic, and was found to be better in low cycle fatigue. This was rationalized3 by postulating that a lamellar reinforcement was more efficient at blocking lateral plastic flow than a rod-like rein-forcement. The purpose of this study is to explore eutectic strengthening in other aluminum base alloys. The Al-Pd system5 forms a eutectic with aluminum and the intermetallic compound A13Pd at 25 wt pct Pd, and has a melting point of 615°C. A13Pd has an orthorhom-bic structure and transforms to hexagonal Pd2A13 at 785°C. Growth characteristics, compression yield strength, creep rupture, and microstructural stability of directionally solidified and as-cast alloys are investigated. Eutectic ingots having a nominal composition of 25 wt pct Pd were prepared by first compacting 1/2 in. diam by a in. high pellets from 99.99+ pct A1 and 99.99 pct Pd powders. The pellets were then levitation cast into 1/4 in. diam by 2 in. long copper molds. Directionally solidified bars were prepared by grinding the cast ingots to 0.195 in. diam, inserting them into alumina

Jan 1, 1970

By J. W. Spretnak, V. Kandarpa

Stress -induced ordering of carbon atoms is studied in a series of Fe-Mn-C alloys. A prominent peak is found in the vicinity of 280°C at frequencies of the order of 1.0 cps, with an associated activation energy of 37 kcal per mole. The height of the peak is linearly rekzted to the concentration of carbon in solution. The distortion of octahedral holes by manganese atoms appears to be predominant over carbon-carbon pair interactions. RELAXATION by stress-induced ordering of point defects is expected whenever the introduction of these point defects produces distortions which have a lower symmetry than that of the lattice. Under zero stress, the isolated point defects occupy the crystallographic-ally equivalent positions in the lattice, as these represent states of equal energy. However, if the defect sites are asymmetric, application of an uniaxial stress will split the energy states, and a redistribution of the defects among various states will take place. This is the case of the internal friction peak called the Snoek peak,1 resulting from isolated interstitials in bcc metals. The interstitial sites in this case have tetragonal symmetry. In the case of fcc and hcp lattices, such an effect is not expected from isolated point defects because of the symmetrical nature of the interstitial sites. However, internal friction peaks arising from interstitial diffusion have been reported both in hcp2,3 and fcc4-8 lattices. These peaks are often explained on the basis of stress-induced ordering of interstitial solutes, caused by the deviation of interstitial sites from their cubic symmetry through the presence of nearby defects. In the case of fcc lattices, evidence for interactions of both the substitutional-interstitial4,6,13 and interstitial-interstitial types5'798'14 have been presented by various investigators. The purpose of the present investigation was to study the internal friction peak attributed to the diffusion of interstitial carbon atoms in high purity austenitic manganese steels and to account for the peak in the light of the existing models. MATERIALS The Fe-Mn-C alloys used in the present investigation were made in two different ways, designated as Type I and Type 11. Type I alloys were made from high purity Fe-Mn alloys obtained in the form of 0.04- in.-diam wires from Materials Research Corporation, Orangeburg, N.Y. These alloys were carburized to different levels using gas mixtures of H2 and CH4 at 1000°C. Type I1 alloys were made in this laboratory starting with zone refined iron, spectrographically pure manganese, and spectrographically pure carbon. They were melted in an argon arc melting furnace and drawn into 0.04-in.-diam wires. All the wires were annealed at about 900°C for 3 hr prior to the internal friction experiments. After the measurements of internal friction, the phases in the samples were identified by X-ray diffraction and the carbon determined by the combustion method. EXPERIMENTAL PROCEDURE In the present work, a classical Ke-type pendulum was used. The details of the equipment were described previously by D. T. Peters.9 Dry helium at 40 torr was used in all the experiments. The internal friction, measured as the logarithmic decrement of the torsion amplitude of vibration was determined as a function of temperature, from ambient to about 500°C. The background internal friction was assumed to have the form of the exponential of the inverse temperature and was subtracted from the raw data. The height of the peak was measured at the position of the maximum in the plot of the internal friction versus temperature. The activation energies of the peaks were measured by the peak shift method. The internal friction values for an alloy were obtained as a function of temperature at different frequencies of vibration. The position of the peak changes with frequency, the higher the frequency the higher the peak temperature. The activation energy of the process associated with the peak is obtained using the formula

Jan 1, 1970

By V. R. Spironello

Operating variables affecting the efficiency of the basic oxygen furnace (BOF) and the level of contaminating elements in the steel product were investigated by the Bureau of Mines. Steel was made in a 400-lb-capacity BOF designed to rotate on its vertical axis to increase the area of hot metal surface subject to oxygen attack. Hot metal for the BOF was made by melting pig iron and scrap in an 18-inch (ID) cupola. The variables were BOF speed of rotation, rate of oxygen flow, number of jets and angle at which they were machined into the oxygen-lance tip, temperature of hot metal, reactivity of lime, and temperature of scrap for the BOF charge. Experiments were arranged according to a two-level fractional-factorial design. The effects of the seven variables were evaluated for 13 responses. The greatest ingot yield occurred while using the larger angle lance tip and jets. The most carbon burned per unit volume of oxygen resulted from rotating the BOF and using the smaller angle lance tip. The largest sulfur transfer to the slag occurred at the higher hot metal temperature levels and higher rate of oxygen flow.

Jan 1, 1970

Underground and strip mining (6,7) produce different hydrologic environments. Many underground mines are below the zone that is completely saturated with water and the mine openings may cause new and continuous contact between sulfurous material and water which flows from the saturated zone to the workings. Strip mines are usually above the zone of continuous saturation and contact between sulfurous material and water is generally restricted to periods of precipitation. A full appreciation of the problem of water pollution caused by drainage from deep mines requires a basic understanding of occurrences and movement of water in the ground and the modes of ground water entrance into mining areas.

Jan 1, 1970

By R. N. Lambert

This chapter discusses the evolution of high-speed shaft sinking in the South African goldfields. Whether we are talking of an additional shaft at an existing mine or the opening of a new mine, the increasing depth of the ore-bearing reef and the unremitting inflation of costs have provided the compelling incentive to shorten the time taken to sink a shaft and start earning revenue. The high costs of sinking a modern shaft system in South Africa are indicated by the recent example of a deep-level mine in the Orange Free State where the cost was nearly $22!42 million. This was for a single large shaft of 33 ft 6 in. diam (in all cases, shaft diameters refer to the finished diameter of the shaft, e.g., inside the concrete) and 7600 ft deep with a prestressed concrete brattice wall dividing the shaft into upcast and downcast compartments. Higher costs and the consequent demand for increased tonnages, deeper shafts with higher rock temperatures, which necessitate highly sophisticaled ventilation and refrigeration requirements, have all accentuated the importance of time in a shaft-sinking operation. Rectangular shafts with their simple design and comparatively reasonable sinking speeds remained popular for many years until greater mining depths combined with a host of the other allied problems inevitably led to changes in shaft design. Circular shafts appeared to offer many advantages, particularly when considering ventilation, strength, mechanization, and sinking through bad ground and heavily watered zones. However, these advantages were largely offset by the slow rate of advance necessitated by the need to stop sinking in order to line the shaft. The development of the curb ring which enabled lining to take place above the bottom of the shaft and the use of multideck stages allowing sinking and lining to be carried out concurrently resulted in a major break- through. Rectangular shafts, which are still popular elsewhere, have been superseded in South Africa by circular shafts which are almost without exception the only shafts sunk in our goldfields today.

Jan 1, 1970

By Milton Ohring, Stephen M. Edelglass

THE recently determined coefficients for diffusion of very dilute impurities in aluminum are shown in Table I. Of these data the activation energies for Ag110, cu54, Mn54 and zn85 are clustered about the value of self-diffusion in aluminum; for the remaining

Jan 1, 1970

By G. W. Diehl, G. A. Griffiths

"Gentlemen, one week ago, I attended the University of Minnesota's Annual Symposium on Mining, in Duluth. A good part of this symposium was dedicated to mill linings of rubber.At this symposium, three mining companies published results from long time full scale tests with rubber linings in mills at four different mines. These were the Republic and Empire Mines of Cleveland Cliffs Iron Company, the Groveland Mine of Hanna Mining Company and the Eagle Mountain Mine of Kaiser Steel Corporation. These papers will be printed in due time and I will not endeavour to relate their full contents, let me only say that in three of the plants, the linings were found to be very economical compared wi.th steel, and that these three are converting over completely to rubber linings, while the fourth, Empire Mine, reported no economical results as far as the shell lining goes, whereas the grates showed promise of becoming economical. The authors of the Cleveland Cliff's paper, however, stated that design improvements in the rubber lining possibly could result in an economical lining also for Empire Mine.That rubber linings in mills, in most cases, show better wear life than steel linings, is known by most of the audience. But, one thing that has not before been disclosed by the endusers is the effect of rubber linings on the grinding economy. All three papers mentioned above reported no change in capacity or grind and two of them reported a decrease in power consumption per ton ground. Hanna Mining reported an average decrease over a three year period for one mill of over 10%. This, of course, puts the economy of a rubber lining in a completely new light. Finally, a point of interest at this meeting was that all three papers emphasized the design aspect, Thus the industry has acknowledged what I believe to be a very important fact - the design of a lining is often more important than the material it is made of."

Jan 1, 1970