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By AIME AIME

ON THE occasion of the eightieth birthday of Captain Robert W. Hunt, the Iron and Steel Committee of the Institute, desiring to commemorate the great contributions made to the steel industry by Captain Hunt during his long career, conceived the idea of a Hunt Medal to be awarded annually by the Institute for meritorious contributions to the art of making steel. The project was received enthusiastically by all to whom it was proposed, especially by Captain Hunt's partners and employees who considered it their right, and asked for the privilege of -. - raising the necessary funds within their own circle. This was agreed to, and the Institute has received from them $7500 as an endowment fund to provide an annual award, and $1000 for the expenses of providing of medal.

Jan 1, 1920

By P. B. Crawford, W. L. Huskey

A study has been made to determine the effects of random vertical fractures existing in a reservoir matrix on the effective matrix properties and producing characteristics of a well. The study indicated that short vertical fractures may distort the isopotentials by 1 percent in the vicinity of the fracture. A correlation was developed which showed the effect of fracture density on the producing capacity of a well. The correlation indicated that fracture shape had little effect on producing capacity, but that total fracture length was closely correlated with the producing capacity. Effective values of reservoir permeability were found to correlate closely with fracture density when measured parallel to the direction of flow. INTRODUCTION In reviewing the petroleum literature, it is found that in most analytical solutions of hydrocarbon reservoir behavior the assumption is made that the rock is uniform throughout although core analysis and well logging surveys indicate that substantially all reservoirs are heterogeneous and some are fractured. Only in recent years have investigators studied the effects of reservoir hetrogeneity. Russell1 discussed the effect of fractures in reservoirs. The literature indicates that fractures greatly affect the exploitation of man reservoirs. This is described by Elkins and Skov2 and Little-field et al. 3 Several types of reservoir heterogeneity have been studied by unsteady-state methods. In 1959, Landrum et al. 4 showed that transient phenomena in hydrocarbon reservoirs could be studied by thermal models. pickering5 studied the flow of heat in stratified linear reservoirs consisting of plates of different metals separated by sheets of rubber which were suddenly exposed to a low-temperature source at one end. Cotman6 studied both laterally and vertically heterogeneous thermal model reservoirs with special reference to cross flow. Another type of reservoir heterogeneity involves the presence of highly permeable, circular lenses around or near the wellbore which was studied by Miesch7 using a thermal and a steady-state model. Many studies have been made of the effects of induced hydraulic fractures on well performance. 8-10 Work regarding vertical fractures that exist initially in the reservoir was reported by Givens, et al.11 Since there appears to be little published work on the importance and influence on reservoir performance of fractures that exist out in the rock matrix, this study was conducted to determine the effects of vertical fractures on pressure distribution, producing capacity and the effective permeability of the reservoir rock. The analogy between the flow of electrical current through a conducting body and the flow of fluid in a porous medium provides a convenient method of studying various aspects of petroleum reservoirs. For electrical radial steady-state flow,12 For steady-state fluid flow, With the above analogy, it is only necessary to establish the ratio of the values of the electrical units in terms of the corresponding flow units to make the analogy quantitative. The ratios are shown below.

By Carl R. Davis, J. L. Willey, S. E. T. Ewing

The first tube-mill on the Rand was put into operation in May. 1904, at the Glen Deep Mine. From that time onwards, tube-mills were added to various plants, although little was known regarding the capacity of a given tube-mill when working on banket ore. Within a few years, however, the so-called standard size (length of shell, 22 ft. 0 in.; diameter, 5 ft. 6 in.) was generally used until the last year or two. Practically the only exceptions were about 30 tube-mills having a length of 16 ft. and a diameter of 6 ft., and a few open-end mills of the roller-supported type. Most of the information obtained during the last 15 years has been obtained with mills of the standard dimensions. The adoption of the tube-mill as an accessory to the stamp mill was rapid; and where 3 tube-mills were working on the Rand at the end of 1904, 244 were in use seven years later.' By 1910, good practice provided 1 tube-mill for 20 stamps of 2000-lb. falling weight. The horsepower of the motors driving the tube-mills had increased from 80 to 100 and then to 125 at this date. Broadly speaking, current practice at that date aimed at a ha1 product of which 60 per cent. was suitable for sand treatment and 40 per cent. for slime. The sand grading was +60 mesh, 6 per cent.; +90 mesh, 25 per cent.; — 90 mesh, 69 per cent.; and the slime grading +200 mesh, 2 per cent.; —200 mesh, 98 per cent. It was recognized comparatively early that the tonnage of — 90-mesh product produced by a tube-mill per 24 hr. was a convenient measure of

Jan 1, 1925

Jan 1, 1889

By O. C. Holbrook, George G. Bernard

A new theoretical treatment has been obtained for the behavior of pattern waterflood injection wells when closed in. Two cases are treated: Case I where oil and water are assumed to have the same properties, and Case 2 where they arc different. In applying the method, one plots log (p — p,) vs closed-in time, where p is well-bore pressure at any tims and p, is static pressure. The value of p. is determined by trial and error as that value which makes the plot linear at large time. A value for the permeability-thickness product can be determined from the intercept of this linear part, and a value of the skin factor from the injection pressure at time of closing in. Application of the method to data from water floods at three fields seems to give reasonable results. For the case of unit mobility ratio, it is proved that this new method should give the same value for permeability-thickness product as the conventional pressure build-up method. In addition, the new method gives correct values for static pressure, whereas the conventional method does not, often indicating negative static pressures. The new method may be used in cases where the surface pressure persists after closing in as well as in cases where it does not. INTRODUCTION It is of considerable interest and importance to be able to determine the characteristics of the reservoir in an area surrounding a water injection well. Thus, if we can determine early in the life of an injection well that there is a considerable "skin effect", remedial measures can be started before a full-scale pattern flood begins. Similarly, if it can be shown that a gradual buildup of skin effect is occurring with time, measures to free the water of plugging material can be taken. Determination of static pressure in the water-injection well may show that the water is entering a thief zone and not the desired reservoir. Finally, determination of the permeability of the sand around the injection well will allow estimation of the future relation between injection pressure and rate. It should be possible to determine average reservoir permeability, skin effect and static pressure from pressure fall-off data. However, at the time we began work on this subject, it was thought that no adequate theory on which to base such determinations' was available. According to the conventional method which considers the reservoir to be filled with one fluid of small compressibility (see Van Everdingen, Joers2, and Nowak2), shut-in pressure is plotted vs log where is injection time, and At is closed-in time. The physical significance of injection time, may well be questioned in this case, since in a reservoir completely filled with a single fluid (as required by this theory) and with input and output rates equal, the pressure behavior after an initial transient is independent of t,. Attempts by our Tulsa area to use this theory led to negative values of static pressure in most cases. Because of these limitations of the method discussed above, it was decided to attempt to develop a new theory of pressure behavior in water injection wells, one which would apply when there is a gas saturation, as is so often the case in water floods. In the following treatment the assumptions and basic equations are given first, then the method of application of the equations. A complete example is given to clarify details of application. All difficult mathematics has been placed in the appendices so that the reader can follow the text without difficulty. However, if he wishes only to apply the results without knowing the basis for them, he can learn how to do this from reading only the sections entitled "Plotting of Experimental Results" and "Example." ASSUMPTIONS AND BASIC EQUATIONS Statement of Problem It will be assumed that a horizontal layer of constant thickness contains in its pore system a mixture of oil, gas and water. While water is being injected into this pore- system through a well at constant rate, an oil bank is built up, gas being expelled from the space taken by the oil as shown in Fig. 1. The saturations within each

By Tracy L. Atherton

THE mapping of slant-hole oil fields is complicated by the fact that relationships between wells are subject to variations in three dimensions and are not readily adaptable to representation on a plane surface. Formalized perspectives usually expand into an undecipherable maze of lines and peg models with the necessary supporting dividers serve only to awe the beholder with their perplexity. The usual compromise arrived at is a plotting of the projection of the courses of all of the wells in the field onto a horizontal plane (Fig. I). These complicated plots, when used in conjunction with the individual vertical projections of the wells, heretofore have been the most practical foundation for the study of general field problems. This method has many shortcomings, however, which are not found in the recently developed straight-hole equivalent projection method. The new method supplies a series of maps similar to the type now in common use in straight-hole fields. It is remarkably simple to use and supplies a ready check on clearances between wells. Perhaps the method can best be understood if the steps that led to its development are described. Common practice of oil-well surveyors is to supply the owner with a tabling of the survey and a plan view plotted against the true meridian. If a vertical projection is plotted, it is usually plotted separately and shows vertical depths against the projection of the stations along a section line joining the top and bottom of the hole on the plan view. A more practical method would be to plot the section line of the plan parallel to the abscissa of the vertical projection (Fig. 2). If this is done, any line parallel to the "base line" will pass through the points on each projection that represent a single point in the hole. Another very useful graph, which the well surveyor could provide, would be plotting of vertical depths against measured depths. Fig. 3 illustrates the next step facilitated by this form of plotting. The lines designated "well A" represent the proposed course of a hole to be drilled. Superimposed on the drawing, in its proper relative position, is the plan view and a portion of the vertical projection of a present producer, "well B." From an inspection of the plan view we arrive at the correct conclusion that the only indicated possibility of collision is at the point of crossing of the wells on the plan view. Referring to the vertical projection, note that the vertical depths of stations on B, in the vicinity of the crossing, are plotted on the same plane of projection as A. The clearance is the indicated distance between the two vertical sections measured along the parallel to the "base line," which passes through the point of intersection of the plan view. Repeat this process for the other wells crossing the proposed course of A on the plan view and you have a preliminary check of clearance for the proposed course. A similar comparison of crossings on the vertical projections of all

Jan 1, 1941

By E. Houdremont, H. Schrader, H. Bennek

The different influences exerted by the various alloying elements in iron and iron-carbon alloys give rise to a great number of complexities, which are difficult to grasp. It is important therefore to study any systematic relations that may exist between the effects exerted by the various alloying elements, in order to obtain a general classification and thus a clearer conception of the nature of alloy steels. A systematic survey of the alloys of iron, based on an investigation of the binary equilibrium diagrams, was recently published by Wever. Although his work deals little with properties of importance in works practice, its purpose being rather to point out the theoretical agreement among the types of binary equilibrium diagrams and the position of the alloying elements in the periodic system (atomic radii, etc.), the classification proposed nevertheless also suggests relationships among the properties of the alloys in question, even though the alloys may contain carbon in addition to iron and the alloying element. Wever divided the alloys of iron into one group exhibiting an open or enlarged gamma field and another exhibiting a closed or restricted gamma field, with both groups capable of further subdivision depending upon whether a continuous series of solid solutions is formed, or, owing to the separation of compounds, etc., only a limited series. Thus all alloying elements which with iron form a closed gamma field, a "gamma loop," produce alloys that beyond the composition corresponding to the greatest extent of the gamma loop are composed of ferrite alone at all temperatures. Alloys of this composition accordingly are not susceptible to ordinary heat treatment because of the lack of transformations. Steels of this class may thus be divided into steels that contain less than the critical amount of alloying element, and are subject to heat treatment, and those that contain more than the critical amount of alloying element and are not subject to heat treatment. Thus chro-

Jan 1, 1935

By H. Schrader, E. Houdremont, H. Bennek

The different influences exerted by the various alloying elements in iron and iron-carbon alloys give rise to a great number of complexities, which are difficult to grasp. It is important therefore to study any systematic relations that may exist between the effects exerted by the various alloying elements, in order to obtain a general classification and thus a clearer conception of the nature of alloy steels. A systematic survey of the alloys of iron, based on an investigation of the binary equilibrium diagrams, was recently published by Wever. Although his work deals little with properties of importance in works practice, its purpose being rather to point out the theoretical agreement among the types of binary equilibrium diagrams and the position of the alloying elements in the periodic system (atomic radii, etc.), the classification proposed nevertheless also suggests relationships among the properties of the alloys in question, even though the alloys may contain carbon in addition to iron and the alloying element. Wever divided the alloys of iron into one group exhibiting an open or enlarged gamma field and another exhibiting a closed or restricted gamma field, with both groups capable of further subdivision depending upon whether a continuous series of solid solutions is formed, or, owing to the separation of compounds, etc., only a limited series. Thus all alloying elements which with iron form a closed gamma field, a "gamma loop," produce alloys that beyond the composition corresponding to the greatest extent of the gamma loop are composed of ferrite alone at all temperatures. Alloys of this composition accordingly are not susceptible to ordinary heat treatment because of the lack of transformations. Steels of this class may thus be divided into steels that contain less than the critical amount of alloying element, and are subject to heat treatment, and those that contain more than the critical amount of alloying element and are not subject to heat treatment. Thus chro-

Jan 1, 1935

By Walter Crafts, C. M. Offenhauer

IN a previous study' of the carbide phase of chromium steels, it was shown that chromium carbide (Cr7C3) is a more stable carbide than cementite (Fe3C) at tempering temperatures above about 500°C. in quenched steels containing from about r1to 7.5 per cent chromium. Below this temperature the carbide phase was found to consist of cementite in all of the steels examined. In the present investigation it was found that a similar change in the carbide phase takes place in molybdenum and in chromium-molybdenum steels at approximately the same tempering temperatures. The approximate ranges of occurrence of the alloy carbides Cr7C3, Cr4C, and Mo2C have been determined in steels containing up to 5 per cent chromium, 1 per cent molybdenum and 0.60 per cent carbon. The experimental steels were made in small high-frequency furnaces from Armco ingot iron, low-carbon ferrochromium and calcium molybdate and were poured into 2-in. ingots, which were forged to 1-in. round bars. Sections of the bars were heated to the carbide-solution temperature and cooled rapidly to induce austenite transformation at relatively low temperatures. The steels were subject to some segregation, therefore comparatively high temperatures were necessary to dissolve all of the carbides. The microstructure of the quenched specimens was examined to verify the belief that the carbides had been dissolved, and also to determine the nature of the nonmartensitic structure of incompletely hardened steels. Ferrite and pseudomartensite were present in some of the specimens, but all specimens were quenched at such a rate that pearlite was not formed, in order to ensure the formation of the carbides at temperatures lower than about 500°C. It had been found previously' that in chromium steels the chromium carbide could be produced by transformation of austenite in the pearlite range above 500°C., and, in order to start the tempering treatment with the carbide present as cementite, the absence of pearlite was considered to be essential. The specimens were tempered for 64 hr. to permit the formation of the stable carbide. After tempering, the specimens were submitted to microscopic and X-ray examination. The carbides were separated either electrolytically in a 5 per cent HCl electrolyte or with an acidified copper-potassium chloride solution. The crystal structure of the carbide phases was determined by the Debye-Scherrer type of X-ray patterns. The X-ray patterns obtained from specimens near the boundaries between two types of carbides were generally weak and diffuse as compared with the other patterns. For this reason, and because the more soluble components may be masked, the boundaries between the phases could not be determined precisely. However, the X-ray analysis of electrolytically separated carbides has given consistently reproducible results

Jan 1, 1943

By OTTO HERRES

TO operate the bituminous coal industry in the United States in 1929 cost $770,237,000, of which $30,739,000 was paid for purchased power and $34,947,000 for new machinery and equipment. Equipment aggregated 3,124,000 hp. A mining industry that spends $65,000,000 a year for power and machinery is likely to be fairly well mechanized, and when the machinery in use takes three million horsepower to drive it, the probabilities are that mechanization has been in progress in at least some of the mines for quite a few years. Mechanization in its broadest sense implies machine cutting, power drilling, mechanical loading, electric haulage, mechanical sizing and cleaning, and lesser applications of machinery to mining operations. But the introduction and development of mechanical loading has been the feature of coal mining recently and its extraordinary progress is causing great changes within the industry. First, let us look at the records. The quantity of coal loaded mechanically in bituminous mines was:

Jan 1, 1933

By Claudio Barsotti, Leonard C. Kitchener

INTRODUCTION The major mining operations of the Ontario Division of Inco Metals Company are located in the Sudbury Basin. Around the rim of this geo- logical formation and within thirty miles of the City of Sudbury are located eleven under- ground mines of the Company, two of which are on standby. In addition, there is one mine in Northwestern Ontario at Shebandowan, 1127 Km (700 miles) northwest of Sudbury. In 1980 ore production totalled 10.6 x 10 mt (11.7 million tons) from underground and open pit operations. Underground mining methods include blasthole, vertical retreat, sublevel caving, cut-and-fill and undercut-and-fill. Inco reduction operations in the Sudbury area include two concentrators, one smelter, one iron ore recovery plant, a copper refinery a nickel refinery and a high purity plate rolling mill. As well, an electrolytic nickel refinery is located on Lake Erie at Port Colborne, near Niagara Falls. In the Sudbury District, Inco employees total 14,278 of whom 6,490 are directly employed in the mining and milling operations. I T H DRILLING Background - The use of long blastholes in underground operations at Inco mines in the Sudbury district started more than 30 years ago at the Levack Mine. At that time, diamond drills were used to mine ore by open stoping and for pillar recovery. By the 1950's the concept had been extended to all mines. The heavy percussion drill was also developed by this time and led to the acceptance of the 11.43 cm (4% in.) piston diameter drifter for bar and arm and fan drill applications. The use however, of the nominal 5.08 cm (2 in.) diameter blastholes drilled radially from the level or sublevel causes overdrilling at the periphery. As well, the smaller holes are subject to hole deviation, are difficult to drill beyond 38.1 m (125 ft.) and require the need for several drilling horizons or sublevels. The need to improve blasthole stoping techniques and our experience with large diameter blastholes in open pit mining led to the trial of an I T H drill in 1962. The test was unsuccessful however, since button bits were not available at the time and the tungsten carbide cross bit experienced short life, gauge loss, and caused hole deviation and poor penetration rates. The successful application of the raise borer beginning in 1964 and the ability to drill 20.32 cm (8 in.) to 27.94 cm (11 in.) diameter pilot holes led to the development of smaller, more portable, rotary drills for blasthole mining. As a result, a mining method based on the use of 20 cm (7 718 in.) diameter, 60.1 m (200 ft.) long rotary blastholes was developed and tested successfully at our C.C.North Mine. Between 1972, when the method was first tested, and 1973 over 4572 m (15000 ft.) of large holes were drilled with rotary drills in the recovery of 175,960 mt (194000 tons) of primary stoping and pillar remnants. A new mining method was developed that made use of this large hole drilling equipment. Instead of longhole carbide drilling by bar-and-arm or fan drill set-ups at sublevels, the large diameter holes were drilled full stope height from the top sill, which substantially reduced development, drilling time and improved fragmentation. These drills however, were difficult to move and set-up, and had a high maintenance cost and low productivity. The capital outlay and extensive technical development required to improve these drills and reduce the high drilling costs however, was economically unattractive. New development in drills and button bits INTRODUCTION The major mining operations of the Ontario Division of Inco Metals Company are located in the Sudbury Basin. Around the rim of this geo- logical formation and within thirty miles of the City of Sudbury are located eleven under- ground mines of the Company, two of which are on standby. In addition, there is one mine in Northwestern Ontario at Shebandowan, 1127 Km (700 miles) northwest of Sudbury. In 1980 ore production totalled 10.6 x 10 mt (11.7 million tons) from underground and open pit operations. Underground mining methods include blasthole, vertical retreat, sublevel caving, cut-and-fill and undercut-and-fill. Inco reduction operations in the Sudbury area include two concentrators, one smelter, one iron ore recovery plant, a copper refinery a nickel refinery and a high purity plate rolling mill. As well, an electrolytic nickel refinery is located on Lake Erie at Port Colborne, near Niagara Falls. In the Sudbury District, Inco employees total 14,278 of whom 6,490 are directly employed in the mining and milling operations. I T H DRILLING Background - The use of long blastholes in underground operations at Inco mines in the Sudbury district started more than 30 years ago at the Levack Mine. At that time, diamond drills were used to mine ore by open stoping and for pillar recovery. By the 1950's the concept had been extended to all mines. The heavy percussion drill was also developed by this time and led to the acceptance of the 11.43 cm (4% in.) piston diameter drifter for bar and arm and fan drill applications. The use however, of the nominal 5.08 cm (2 in.) diameter blastholes drilled radially from the level or sublevel causes overdrilling at the periphery. As well, the smaller holes are subject to hole deviation, are difficult to drill beyond 38.1 m (125 ft.) and require the need for several drilling horizons or sublevels. The need to improve blasthole stoping techniques and our experience with large diameter blastholes in open pit mining led to the trial of an I T H drill in 1962. The test was unsuccessful however, since button bits were not available at the time and the tungsten carbide cross bit experienced short life, gauge loss, and caused hole deviation and poor penetration rates. The successful application of the raise borer beginning in 1964 and the ability to drill 20.32 cm (8 in.) to 27.94 cm (11 in.) diameter pilot holes led to the development of smaller, more portable, rotary drills for blasthole mining. As a result, a mining method based on the use of 20 cm (7 718 in.) diameter, 60.1 m (200 ft.) long rotary blastholes was developed and tested successfully at our C.C.North Mine. Between 1972, when the method was first tested, and 1973 over 4572 m (15000 ft.) of large holes were drilled with rotary drills in the recovery of 175,960 mt (194000 tons) of primary stoping and pillar remnants. A new mining method was developed that made use of this large hole drilling equipment. Instead of longhole carbide drilling by bar-and-arm or fan drill set-ups at sublevels, the large diameter holes were drilled full stope height from the top sill, which substantially reduced development, drilling time and improved fragmentation. These drills however, were difficult to move and set-up, and had a high maintenance cost and low productivity. The capital outlay and extensive technical development required to improve these drills and reduce the high drilling costs however, was economically unattractive. New development in drills and button bits

Jan 1, 1981

By W. W. Anderson

A formula for quantitative efficiency is proposed, in which the efficiency value is a function of the improperly distributed material at the, gravity of separation effected by the cleaning equipment. The misplaced material is expressed as a percentage of the total material discharged from the equipment. Numerous examples are given, demonstrating application of the formula to various types of separation, including multiple-product separations.

Jan 1, 1950

By Robert B. Sosman

ONE of the most neglected fields for physicochemical education as well as for research is that of high-temperature phenomena. Few universities or technical schools give instruction in the physical chemistry of substances at high temperatures. On the contrary such instruction is almost entirely confined to the region between the freezing and boiling points of water. This field should be extended to a much wider range of temperatures, both low and high. Such an extension is logical, sound, feasible, and practical.

Jan 1, 1943

By T. L. Berger, M. C. lnman, M. F. Rose

AFTER shock loading, mechanical twinning has been observed by several authors1-4 for a variety of fcc metals and alloys. It has been shown2,3 that low stacking fault energy materials deform primarily by the formation of mechanical twins and stacking faults during dynamic loading. Further, Inman, Murr, and Rose2 have shown that a correlation exists between the average hardness and the volume percent of mechanically twinned material in stainless steel. It has been observed in nickel' that mechanical twins are produced during shock deformation if the peak pressure associated with the shock wave is greater than 350kbar. It is the purpose of this work to discuss shock-hardening mechanisms in nickel and to determine to what extent the initial condition influences the final response. The "flying plate technique" was used to generate planar shock waves with peak pressures as high as 710 kbar. The details of the technique5" have been discussed elsewhere and will not be repeated here. The material used in this study was polycrystalline nickel of 99.98 pct purity and had an initial grain size of 0.18 mm. Prior to any deformation, all samples were given a stress-relief anneal of 6 hr at 600°C in a vacuum furnace. After annealing, the initial condition of the samples was changed by cold rolling individual samples from 0 pct to a maximum of 80 pct reduction in thickness. This provided samples with controlled initial histories for shock deformation. Immediately after shock loading, the specimens were slowed and quenched by suitable arrangement of buffer material and water bath. This technique minimized specimen damage and the effects of shock heating on the samples. Since deformation twins in high stacking fault energy fcc metals are only produced at high stress levels, the initial defect configuration prior to mechanical twinning should greatly influence the number of twins formed. In fact, Zukas and Fowler7 have found that prestraining in iron and steel greatly suppresses the formation of mechanical twins during the shock deformation process. Following the methods of Warren and warekois8 and Cohen and Wagner,9 X-ray diffraction profile analysis was performed to determine the incidence of stacking faults and mechanical twins in the deformed nickel. Analysis was made on samples in the annealed, cold-rolled, shock-loaded, and cold-rolled—shock-loaded states. The estimated accuracy of the peak position measurements is *0.01 deg in 2?. Therefore the accuracy in the measurement of the relative peak shifts between the (400) and (222) diffraction line profiles is on the order of *0.04 deg in 2?. None of our measurements indicated peak shifts greater than 0.04 in 28. This would correspond to a fault density of -1 pct and sets the limit on the sensitivity of our instrument. Similarly, analysis of the shift in the center of gravity of the diffraction line profiles yields the minimum measurable value of the twin fault probabilitya to be -0.002. Fig. 1 shows mechanical twinning in nickel shock-loaded to 400 kbar. In this photograph, fault intersections are clearly visible. The thickness of the individual fault lamellae was determined from the image widths of their lines of intersections by the

Jan 1, 1968

By George S. Rice

GROUND movement and subsidence is an important matter from several points of view and it is regrettable that more papers have not been written on this subject in the past year. Damage may be done to surface buildings or to the higher workings of a mine, and a study of the subject gives valuable in- formation on hanging-wall or roof control. The latter objective is strikingly shown in a recent paper presented by Jack Spaulding on Oct. 21, 1937, before the Institution of Mining and Metallurgy, of Great Britain, entitled "Theory and Practice of Ground Control in the Kolar Gold Field, India." All may not agree with some of his theories that were deduced from studies of the many violent rock bursts at depths of 5000 to 7000 ft., but the data obtained are of great value. His theories of symmetrical ring stresses and symmetrical domes which are pictured as perfect are rather hard to understand as such uniformity is un- likely in view of the irregularities in the formation due to folds and fractures of various kinds. All will agree in principle with this idea of domal effects, which have been observed in many countries, but they are generally irregular.

Jan 1, 1938

By B. W. Howlett, M. B. Bever, Somnath Misra

The heats oj- formation at 0°C of the compounds AuSn,, AuSn2, AuSn, and the £ phase were measured in a metal -solution calorimeter with liquid tin or a liquid Sn-Bi alloy as solvent. The melting point, heat of fusion, and heat capacities near the melting point of- the compound AuSn in the solid and liquid state were measured in a constant temperature gradient calorimeter. The free energy and entropy of formation of the compound AuSn at its melting point and at 298 °K were calculated from the experimental results and published data. The heats of formation are discussed in relation to the nature of the compounds. The heat capacity below the melting point, heat of fusion, and entropy of fusion of AuSn are interpreted in terms of processes oc-curring before melting. The atomic arrangement in liquid Au-Sn alloys and the bonding in the intermediate phases of. the Au-Sn system are discussed in the light of the measured thermodynamic properties. THE available thermodynamic information on the intermediate phases in the Au-Sn system consists of the heats of formation of the compounds AuSn4, AuSn2, and AuSnly2 and of one composition of the < phase2 besides values of the heat content of the compound AuSn from 0" to 635".&apos; However, the heats of formation refer to different temperatures ringing from 90" to 450°C. Also, the reported error limits of some of the values are large and several inconsistencies are apparent. In the investigation reported here the heats of formation of the compounds AuS-, AuSnz, and AuSn and of three compositions of the < phase were determined for a single reference temperature of 0°C by liquid metal-solution calorimetry. The compound AuSn, which is the only congruently melting intermediate phase in this system, was further investigated in a constant temperature gradient calorimeter by measuring its heat of fusion, melting point, and heat capacity in the solid and liquid states near the melting point. From these data and published free energies of the liquid of composition Au~n,&apos; the free energies of formation of the compound AuSn at the melting point and at 298°K were calculated. The results shed light on the solid-liquid transition of AuSn and on the atomic bonding and state of association of gold and tin in the solid and liquid phases. 1) EXPERIMENTAL PROCEDURES 1.1) Preparation of Samples. Stoichiometric amounts of gold and tin, each 99.99+ pct pure, were melted in evacuated Vycor capsules (12 mm ID). The melts were maintained approximately 150°C above the liquidus for about 12 hr and shaken repeatedly. Samples of the compound AuSn were cooled slowly to room temperature. Melts of the other phases, all of which solidify by peritectic reactions, were transferred to the narrow end (5 mm ID) of the capsule, which was then quenched into iced brine. The solidified samples were annealed in the unopened capsules for 10 days at 30" to 50° C below the respective solidus temperatures. The absence of microsegregation and second phases was confirmed by metallographic examination. At least two batches of each composition were prepared. 1.2) Solution Calorimetry. The heats of formation were determined by liquid metal-solution calorimetry. In this technique, the difference between the heat effects on dissolution in a liquid metal, or alloy bath, of the compound and a mechanical mixture of its annealed components, adjusted for changes in composition of the bath, is the heat of formation of the compound at the temperature from which the samples are added. Details of the equipment and technique have been described."&apos; A tin bath at 300" or 350°C was used with the compounds AuSn,, AuSnz, and AuSn. The high gold content of the £ phase would have caused it to dissolve with an appreciable exothermic heat effect. In order to achieve thermal compensation, the samples were added from 0°C to a bath at 350°C consisting of 66.2 wt pct Bi (99.999+ pct pure), balance Sn (99.99+ pct pure). This solvent gives thermal compensation because gold dissolves exothermically in tin and endothermically in bismuth. The calorimeter was calibrated by adding from 0°C approximately 0.015 g-atom of the solvent.

Jan 1, 1965

By Edwin H. Olson, Morton Smutz, Charles J. Baroch

IN 1949 an orebody containing some 10 billion lb of recoverable rare earth metals was discovered in the Mountain Pass district of San Bernardino County, California.1 The following year Molybdenum Corp. of America purchased a number of claims at the deposit and a mill on the property which had been constructed to process the district&apos;s gold ores. Average composition of ore from the San Bernardino deposit is less than 0.1 pct ThO2, 25 to 35 pet calcite, 10 pet rare earth oxides, 15 to 20 pet silica, and 30 to 40 pet barite.2 Rare earth content of the ore analyzes 50.7 pet CeO2, 4.2 pet Pr6O11, 11.7 pet Nd2O3, 1.3 pet Sm2O3, and 34.3 pet La2O3, and others.2

Jan 3, 1959

By S. R. B. Cooke, Iwao Iwasaki, Hyung Sup Choi

John Dasher (Materials and Processes Engineer, Crucible Steel Co. of America, Pittsburgh, Pa.) The authors are to be congratulated for their excellent work, dramatic results, and persuasive explanation on the neglected subject of the temperature variable in soap flotation. The explanation includes why heat is helpful in conditioning and why heat is helpful in flotation. This is a fine start, but I hope the work will be continued to show which is the major effect. In the work of Noman and Dash er(1) it was found that substantially all the benefit of heat came from the conditioning step, and that results were much better if a thick pulp was conditioned hot and then diluted with unheated (or less heated) water for flotation (or agglomerate tabling) than if the same quantity of heat was used to condition and float at some intermediate temperature. In other words, heat for conditioning gives a Rood return, but additional heat for dilution water is near or beyond the point of diminishing return. Strathmore R. B. Cooke, lwao lawsaki, and Hyung Su0p Choi (Authors&apos; Reply) Mr. Dasher&apos;skind comments on our paper are appreciated. In view of the relative simplicity of empirical investigationsof the temperature variable upon conditioning and flotation, it ispuzzling why the subject is so neglected. Our work, being sub sidiary to the main investigation of the effect of structure of fatty acid collectorsupon iron ore flotation, was quite restricted, but we intend to return to the subject as soon as possible. Mr. Dasher&apos;s point, that given a certain number of calories it is better to invest them for conditioning in a thick pulp rather than to spread them out for both conditioning and flotation operations, is well taken and cannot be argued. On the other hand there is no question that high temperature during the flotation of iron ores induces superior frothing characteristics, and, in particular, greatly augments the rate of flotation and markedly decreases the time required for "difficult" particles to float.

Jan 1, 1961

By A. P. Coldren, V. Biss

SINCE the r ? a transformation rates of many carbon-free ferrous alloys and low-carbon alloy steels are relatively fast, conventional equipment is not suitable for the dilatometric determination of continuous cooling transformation diagrams. On the other hand, a method based on metallographic analysis of quenched specimens would not be practicable because the various products of shear-dominated transformation are essentially indistinguishable in low-carbon iron-base alloys. Both problems may be avoided by a thermal analysis method employing gas quenching of small specimens austenitized in vacuo. The laboratory equipment employed in the present study consisted of a Tektronix Type 564 Storage Screen Oscilloscope and a Kinney high-vacuum evaporator, modified as shown in Fig. 1, to permit heating a small specimen and cooling it slowly by programmed cooling or rapidly (up to about 8000°F per sec) by a controlled quench with helium gas. The oscilloscope records the electromotive force of a 40-gage (0.003-in.-diam) Chromel-Alumel thermocouple in the specimen during cooling. The temperature at which the cooling curve begins to show the influence of the heat produced by the phase change in the specimen was arbitrarily taken as the transformation-start temperature.*

Jan 1, 1970

Since its organization, in July, 1917, the War Minerals Committee of the Institute, of which William Y. Westervelt is chairman, has been studying important phases of the mineral industry and its relation to winning the war. From this has come a realization of the imperative need for more definite coordination than is possible without direction by some governmental agency. No privately controlled industry can have the detailed knowledge of war needs or the control of all its supplies and markets necessary to effect the adjustment of its activities for war purposes. Inevitable shortages of certain essential minerals confront us unless immediate steps are taken to stimulate and develop. the mining

Jan 2, 1918