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By Gardner F. Williams

These mines are situated in Griqualand West, which is now a part of the Cape Colony. The town of Kimberley is in latitude 28o40' South, longitude 25o10' East, about 640 miles northeast of Cape Town and 450 miles from Port Elizabeth on the east coast. It is connected with these towns by a railroad, which has been completed during the present year. The mines are located in a desert country, resembling the desert portion of Arizona. The elevation above sea-level is about 4000 feet. The climate is exceedingly hot during the summer months. Diamond Deposits.—There are four large diamond-bearing deposits at Kimberley, all lying within a radius of one and one-half miles, having the De Beers mine as the center. These are named the " Kimberley," " De Beers," " Du Toit's Pan," and " Bultfontein " mines. There is, also, directly west of the Kimberley mine, a small deposit, called " St. Augustiue," which has been prospected only, and

Jan 1, 1887

By C. R. Austin

THE paper describes an investigation on the pressure welding of low-carbon steels. The work necessitated a reproducible mechanical means of making the weld and also a test that would indicate the nature and completeness of the union. An apparatus including a high-temperature furnace was devised for making the welds, and the ordinary tensile pulling test 'in correlation with macroscopic and microscopic observations was used as a means of examining the result. Initially it was intended to devise some simple test of weldability, but as the experimental work progressed, it soon became clear that with our limited knowledge of the exact nature of the mechanism of pressure welding it was impossible to interpret our results or to devise a simple test of weldability. Hence it was manifestly necessary first to study the mechanism of such welding and attempt to elucidate the fundamentals underlying the so-called welding of steel by pressing together two metal surfaces. It also became evident that it was necessary to define the term "welding." In many early experiments when, two heated rods were pressed together and then pulled in the cold, very high tensile values were obtained, and yet the fracture took place exactly in the line of junction except for a few small scattered areas. In other words, the' rods pulled apart just as they were before being "stuck" together and had certainly not welded completely, despite the high value indicating the strong cohesive force operating. In this paper, welding has been considered as a form of intimate contact between two metal surfaces, so that the units lose their individual identity and there is no change in physical properties in passing through the weld from one unit to the other. This is defined as "true welding." When true welding has taken place completely over the whole section, the probability is that the rupture in tensile test will occur outside the weld.

Jan 1, 1932

By Hallan N. Marsh

The subject of this paper is apt to bring to mind wells ranging from 6000 to over 8000 ft. in depth. However, it is uncommon to pump wells at depths greater than about 5000 ft. Fig. 1 shows the number of wells being pumped at various depths by one company in Southern California. A few companies have a very few wells pumping at depths greater than this. This paper will deal with wells between 3000 and 5500 ft. in depth. Most California oils at these depths are between 25" and 35" gravity. The subject is so broad that it will be necessary to omit many interesting phases, and to treat others very briefly. Power, power transmission equipment, power efficiency, counterbalancing, sucker rods, pumps and volumetric efficiency will be discussed. Power As a source of power, the 50/20-hp. electric motor is generally preferred. Input is generally between 10 and 25 hp. Due to the uneven-ness of the load, an input of 20 hp. on the low range is generally about all that these motors will carry without overheating, in spite of their overload capacity. In some cases the capacity of the motor limits the speed

Jan 1, 1929

By Lyman H. Hart

Some of the significant facts that will affect the supply and demand for metals during the next few decades are given in this presentation. This is important because the only hope for intelligent guidance of the national destiny depends upon presenting a consistent and accurate picture of basic problems. The metals problems now fomenting are only slightly less important than those precipitating the energy crisis. Admittedly, it is difficult to generate serious thinking on this subject when the world is enjoying easy access to all metals at modest prices. This is possible because of the current world capacity to overproduce, and United States credit standing, at least up to now, has permitted buying freely on world markets. Although both these vital conditions are subject to change, there is little doubt that if the U.S. financial house is kept in order, we can muddle along for a while on a generally expanding, metalbased economy. But should our credit standing be permitted to collapse, or should there be a tightening of world supplies of metals, the nation would immediately find itself in trouble. Unfortunately, clear signals indicate that both of these conditions are threatening.

Jan 4, 1973

By M. R. Geer, H. F. Yancey

Although the use of dense suspensions for coal cleaning was pioneered in the United States with the Chance sand flotation process, and during the past year a pilot plant using a magnetite suspension has started operation in this country, the more recent developments in this field of coal cleaning have occurred principally in the Netherlands. During the thirties the Dutch developed the Barvoys process, in which a medium of barite and clay is employed, the Tromp process, which utilizes a magnetite suspension, and the Loess process, in which is used the air-borne earth or soil known as loess.1-3 All these processes are finding increasing use in European coal-cleaning practice. Now a fourth process, the cyclone cleaner, is under development by the Netherlands State Mines. A cyclone thickener for reclaiming and thickening the dense suspension is a novel feature of the Loess process. Through accident, the discovery was made that the cyclone could be utilized as a cleaning device for fine coal. When the cyclone thickener at the Maurits mine plugged, the overflow was found filled with clean coal free of refuse, and from this observation developed the concept of the cyclone as a coal cleaner. In June 1945 the cyclone cleaner was observed by one of the authors,' and in September 1945 it was described by Dries-sen6 in a paper presented in London before the Institute of Fuel. As the cyclone seemed to offer unusual promise as a means of extending heavy-medium cleaning to the finer sizes of coal that cannot readily be treated in existing heavy-medium processes, the Bureau of Mines, following Driessen's, presentation, launched an investigation of the cyclone as a coal cleaner. Added impetus was given to this study by the present increased interest in heavy-medium cleaning in this country. Object and Scope of Investigation Driessen's report, although comprehensive in many respects, did not include a detailed description of the cyclone cleaner, and contained almost no information on the influence of the various operating variables of the cyclone. It was necessary, therefore, to investigate the influence of the cyclone adjustments on its performance before studying the application of the cyclone to various coal-washing problems. The present report is confined entirely to these preliminary tests, designed to demonstrate the operating characteristics of the cyclone. The investigation has been in progress

Jan 1, 1949

By John Fulton

THE increase in the production of iron has been accompanied by a growing demand for an improved quality, and more especially at the present time, in the manufacture of Bessemer steel, which is rapidly becoming an important branch of industry. This has led the makers of pig iron to a careful investigation of the composition of the materials from which their metal is produced, the inquiry being greatly assisted by a cordial alliance of science and practice. Formerly, chemical science was held in abeyance, or admitted in a hesitating experimental way ; but now it is received as a valuable auxiliary, and its decisions are accepted as final and conclusive. It is called on to assist the iron-maker in determining the quality of his stock, and to detect the presence of injurious elements in his fuel, ores, flux, or iron. The object of this paper is to submit the method now in use at the furnaces of the Kemble Coal and Iron Company in the Broad Top coal and iron region, for removing, by a process of crushing and washing, slate and other impurities from coal, designed, when coked, for furnace fuel. It is not contemplated to claim very advanced progress in this work, believing that it is susceptible of improvement, but to show that some progress has been made in a comparatively new field, and it is hoped in the right direction, since coke is probably destined to become the principal fuel in the metallurgy of iron. The Broad Top coal region occupies an isolated geographical position, standing 25 miles east from the Alleghany field. It is associated with the latter by the structure of its coal, and more closely with the Cumberland field by a similarity in the quality of coal.

By R. C. Philp, Allan Gibb

The term a matte " is applied to smelting-products so extremely diverse in composition and physical properties that it appears impossible to devise any generic formula to represent, chemically, the manner in which the varied proportions of the almost unlimited possible constituents combine with each other. Mattes produced in copper-smelting, in distinction from those produced in smelting-operations in which the recovery of cop per is secondary to that of other metals, cover a narrower range in composition. The copper-content of such mattes vary from 20 to 80 per cent., and even this range is much smaller in general practice since it is found advantageous, when possible, to produce mattes with about 50 per cent. of copper in the first operation. Further, it is unusual that arsenic or antimony occurs in copper-ores in sufficient proportions to form arsenides or antimonides in such quantities that they will separate out from the furnace-products, as is common in lead-smelting. Generally, the mattes produced in copper-smelting are composed mainly of copper (usually greater than 35 per cent.), iron and sulphur, the remaining elements being usually in proportions sufficiently small to allow of their treatment as impuritiee, rather than as essential constituents of the mattes. In modern practice of smelting copper-ores in blast-furnaces the tendency is to approach pyritic smelting as nearly as possible, the furnaces being low and the air supplied being largely in excess of that required for complete combustion of the carbonaceous fuel. Hence, the atmosphere of the blast-furnace thus used is usually oxidizing or nearly neutral, and, as a consequence, the reduction of metallic iron that was a necessary evil of former practice is of unusual occurrence in operations where the main object is the recovery of copper. Hearth-accre-

Jan 1, 1906

By Emby Kaye

It is the purpose of this paper to outline briefly some of the considerations that enter into the economics of so-called recycling, the generic designation of the relatively recently developed process by which a condensate† is separated from gas-distillate gas at high pressure and the residual gas returned to the reservoir. This subject necessarily embraces not only a discussion of factors that should be considered in projecting a recycling operation, such as estimating reserves, investment and operating costs, but also a comparison of condensate with other types of petroleum. The place of condensate in its relation to the total supply of crude oil is pointed out as well as certain logical methods of product disposal. The cost of drilling wells and lease maintenance is not pertinent to this discussion because income and revenue are in this paper confined to that retained by the plant or plant operator for supplying processing facilities for the gas. Before the development of recycling a great many gas-distillate gas fields in Louisiana and Texas provided no income to their owners. When gas was sold from these reservoirs it was accompanied by irretrievable losses of condensate in the formation. The understanding of the func- tion of retrograde condensation resulted in the introduction of a new commercial petroleum recovery process for these hitherto unexploited fields and now permits the conditioning of this type of wet gas field for the sale of dry gas therefrom without waste. Some Economic Factors The study of a gas-distillate field for possible exploitation necessarily involves the critical appraisal of a number of elements, chief of which will be discussed here: (I) estimate of distillate in place, (2) estimate of distillate that can be brought to the surface, (3) available market, (4) costs. The considerations affecting the estimating of distillate reserves in place are in the main subject to the same errors as are involved in determining dry gas reserves. Determinable data including acreage, sand thickness, reservoir pressure, reservoir temperature, porosity and connate water provide the basis for calculating the volume of gas in place. Ample allowance must be made for connate water, which may occupy from 20 to 35 per cent of the pore space of the sand. The factor of supercom-pressibility is to a considerable extent nullified by the reservoir temperature. It has been considered well advised to allow this factor to serve as a cushion. With the gas reserves calculated, it remains only to assay the distillate content of the gas. Those familiar with the handling of "wet" gas at high pressure readily appreci-ate the variables in sampling gas from

Jan 1, 1942

By Emby Kaye

It is the purpose of this paper to outline briefly some of the considerations that enter into the economics of so-called recycling, the generic designation of the relatively recently developed process by which a condensate† is separated from gas-distillate gas at high pressure and the residual gas returned to the reservoir. This subject necessarily embraces not only a discussion of factors that should be considered in projecting a recycling operation, such as estimating reserves, investment and operating costs, but also a comparison of condensate with other types of petroleum. The place of condensate in its relation to the total supply of crude oil is pointed out as well as certain logical methods of product disposal. The cost of drilling wells and lease maintenance is not pertinent to this discussion because income and revenue are in this paper confined to that retained by the plant or plant operator for supplying processing facilities for the gas. Before the development of recycling a great many gas-distillate gas fields in Louisiana and Texas provided no income to their owners. When gas was sold from these reservoirs it was accompanied by irretrievable losses of condensate in the formation. The understanding of the func- tion of retrograde condensation resulted in the introduction of a new commercial petroleum recovery process for these hitherto unexploited fields and now permits the conditioning of this type of wet gas field for the sale of dry gas therefrom without waste. Some Economic Factors The study of a gas-distillate field for possible exploitation necessarily involves the critical appraisal of a number of elements, chief of which will be discussed here: (I) estimate of distillate in place, (2) estimate of distillate that can be brought to the surface, (3) available market, (4) costs. The considerations affecting the estimating of distillate reserves in place are in the main subject to the same errors as are involved in determining dry gas reserves. Determinable data including acreage, sand thickness, reservoir pressure, reservoir temperature, porosity and connate water provide the basis for calculating the volume of gas in place. Ample allowance must be made for connate water, which may occupy from 20 to 35 per cent of the pore space of the sand. The factor of supercom-pressibility is to a considerable extent nullified by the reservoir temperature. It has been considered well advised to allow this factor to serve as a cushion. With the gas reserves calculated, it remains only to assay the distillate content of the gas. Those familiar with the handling of "wet" gas at high pressure readily appreci-ate the variables in sampling gas from

Jan 1, 1942

By B. B. Sandiford

It has been known for many years that the efficiency of a water flood can be improved by lowering the water-oil mobility ratio in the system. Such a change leads to better sweep efficiency and also to more efficient oil displacement in the swept zone. Data from our laboratory water-flood tests of both small cores and long sand packs are presented which show that water mobility can be reduced and oil recovery increased by the addition of certain polymer solutions to flood water. The reduction in mobility, in many cases, is greater than would be expected from conventional viscosity measurements. These solutions, however, do not cause significant reductions in oil mobility. The over-all effect of these mobility changes is increased waterflood oil recovery. Encouraged by results of our laboratory work, we expanded our study to include pilot field tests of floods with such solutions. One such test, made in the West Cat Canyon field, Santa Barbara County, Calif., is described in detail in this paper. Three other field tests are also discussed. INTRODUCTION Oil production from most reservoirs following primary depletion and/or water flooding is often less than 50 per cent of the original oil in place. Heavy oil reservoirs seldom yield over 15 per cent of their original oil. With new reservoirs becoming harder to find, the improvement of oil recovery efficiency is one of our very important problems. We describe here some of our attempts to increase the efficiency of oil displacement by adding a water-soluble polymer, partially hydrolyzed polyacrylamide, to flood water. This technique will be termed "polymer solution flooding". The concept of using high-viscosity water to increase the efficiency of water flooding is not new. In 1944 Detling (Shell Development Co.) obtained a patent covering the use of several additives for viscous water flooding.' His objective was to improve water-oil mobility ratios by increasing the viscosity of the flood water. Other patents2-27 have been granted covering specific water-SO~LIble polymers or specific conditions of viscous water flooding. Barnes'" described his laboratory model study of the injection of a viscous water slug into a reservoir which had been partially invaded by bottom water. He concluded that, for this type of reservoir, "the cost of viscous water should not exceed a few cents per barrel for viscous water slug injection to be economically feasible" Our studies have led us to a somewhat different conclusion in a number of cases where hydrolyzed polyacrylamide solutions have been injected into reservoir models or actual reservoirs. Possible reasons for this difference are discussed in this paper. Our studies have shown that polymer solutions may lead to an increase in oil recovery over that from an ordinary water flood by (1) improving sweep efficiency, (2) improving microscopic displacement efficiency, or (3) a combination of these mechanisms. In the work of Barnes, only the benefit of improved sweep efficiency was considered. Also, our work has shown that there are marked differences in the effectiveness of different water-soluble polymers as flood water additives. Partially hydrolyzed polyacrylamide is better than many other water-soluble polymers we have tested because, even in very low concentrations, it can lead to increased oil recovery. This is an important advantage when either a dilute polymer solution is injected continuously or a relatively concentrated slug is injected followed by water. In the latter case! portions of the slug become diluted and function in the formation as very dilute solutions. As dilution takes place the effective slug size will increase which, in turn, will reduce the cost per barrel of the effective flooding medium. The reason that partially hydrolyzed polyacrylamide solutions are more efficient at low concentrations than certain other polymer solutions of equivalent viscosity (when measured in conventional viscometers) is not fully understood. We do know that the shapes and sizes of macro-molecules dissolved or suspended in liquids influence the flow properties of their solutions or suspensions. Solutions of partially hydrolyzed polyacrylamide cause greater reductions in water mobility than would be expected from conventional viscosity measurements. LABORATORY STUDIES Laboratory water floods were run in linear and radial systems with different water-soluble polymers and under varying conditions of flow. including reservoir conditions of temperature, pressure and fluid composition. Some of these runs are considered in this section. OIL DISPLACEMENT IN LINEAR MODELS In this group of runs the sweep efficiency approached 100 per cent because the linear sand packs used were as nearly uniform as possible. Results reflect primarily the micro-scopic displacement efficiencies. The laboratory models were unconsolidat-ed sand packs the lengths of which varied from about 4 in, to 40 ft. Further information on the flow models used is listed in Table 1. Using conventional procedures, water floods were run on sand packs containing either refined or crude oil at restored state. Frequently, a repeat run, similar to the first, was made as a check. Then a third run was made on the restored-state model using either polymer solution or a combination of polymer solution (slug) and water. Details of these runs are also reported in Table 1. In Figs. 1 and 2 results of two different groups of runs are shown in which the oil used was a 62-cp refined oil and the flooding medium

Jan 1, 1965

By N. J. Grant, B. C. Giessen, Paul Predecki

ALLOYS of gold, silver, and aluminum with elements of the groups BII, BIII, BIV, and BV were prepared by a rapid quenching technique (splat) and were examined by X-ray diffraction. Five new intermediate phases were found and will be described briefly herein. For the gold and silver systems, the concentration ranges having an electron/atom ratio e/a of 1.4 to 1.5 ("3/2 Hume-Rothery phases") were studied primarily. Master alloys were prepared from high-purity metals (99.9+ pct or better) by melting either in evacuated fused silica capsules or by nonconsum-able-electrode arc melting in an argon atmosphere. Small pieces, 20 to 50 mg, of each alloy were blast-atomized to form a splat, by a technique similar to that described by Duwez and Willens.1 The technique used for this study is described in detail in Ref. 2; it utilizes a resistance-heated graphite crucible with a small hole at the bottom, directed toward a metal substrate or quenching plate. The prepared alloy rests over the fine hole, through which it is expelled by an explosion shock wave in the form of fine droplets (1 to 50 µ) of molten metal onto a copper or silver substrate, which is maintained at about -190°C. The resulting very high cooling rates (see Ref. 2 for quantitative measurements) can prevent the process of nuclea-tion and growth in many instances, resulting in the formation of metastable phases. The splat particles were transferred to a GE-XRD5 diffractometer and maintained at -190°C, where they were examined with CuKa radiation. The samples were then allowed to warm to room temperature or were heated to higher temperatures until the equilibrium structures formed. Of fifteen alloy systems considered, nonequi-librium structures were encountered in six; these are described below and summarized in Table I. In the system Au-Sb a metastable £ phase (A3 type, hcp, a = 2.898 + 0.002A; c = 4.731 * 0.004A; c/a = 1.633) was found in the concentration range Au + 13 to 15 at. pct Sb. This phase is isomorphous with the stable phases in the systems Au-Cd, Au-In, and Au-Sn, all at an average e/a ratio of 1.4 to 1.5. The concentration range of one-phase metastable was deduced from the small amounts of supersaturated gold solid-solution phase present in the splat product. It was found that ? could also be retained by splatting onto a substrate held at room temperature: however, decomposed into the equilibrium phases Au + AuSb2 after heating to 200°C for 1/2 hr, or on holding the powdered splatted alloy at 20°C for several months. Calorimetric measurements will be made in an attempt to decide the question whether ? is metastable at all temperatures or whether it is a stable phase at low temperatures. There is evidence that another phase, possibly also close-packed but with a different stacking sequence, can be obtained by rapid quenching of alloys with a different antimony content. Klement, Willens, and Duwez3 reported the existence of an amorphous phase on quenching Au-Si alloys (25 at. pct Si) to - 196°C. They found that on heating to room temperature another phase of unknown crystal structure was formed. This was confirmed (see Table I); however, the new crystalline phase, designated as ?, could also be formed simply by rapid quenching to room temperature, and even was found to exist already in the as-cast Au + 20 at. pct Si alloy. It was found that ? decomposed into Au + Si on the specimen surface at room temperature. This behavior, and the question whether or not there is an equilibrium-temperature region for ?, have not yet been resolved. It is probable that ? (Au + 20 to 21 at. pct Si) is cubic of the -brass type (D81-3) with a = 9.60, + 0.01A and N = 52 atoms per cell [compare 6 (CU-Sn)4]. Except for two very weak lines, the powder pattern of about thirty lines could be indexed on this basis; however, a determination of the atom positions has not yet been attempted. For Au-Ge the C phase was observed at about 21 at. pct Ge as reported by Luo et at.5 Lattice parameters a = 2.876A, c = 4.73,A, c/a = 1.64 were found. In the Au-Pb system, formation of a ? phase was not observed, but in the lead-rich region at 75 at. pct Pb, broad peaks belonging to an amorphous phase were found. The maximum diffracted intensity occurred at 28 = 32.4 deg which is about 1 deg larger than the position of the (111) line of lead (Cuka). For Ag-Pb, an amorphous phase analogous to the one found in the Au-Pb system was observed; this metastable phase exists probably at about 75 at. pct Pb. Since no lead-rich alloys were tested, all alloys consisted of silver + amorphous phase at -190°C. In A1-Ge alloys, line-rich and complex powder patterns were obtained at about 30 at. pct Ge; they bear similarities to those of aluminum and germanium, but are of lower symmetry; the existence of more than one intermediate phase is possible. The authors are grateful to the Kennecott Copper Corp. for Fellowship support, and ARPA (Contract

Jan 1, 1965

By Paul B. Crawford, Melvin B. Burton

A procedure is given which describes how the gelatin model may be-used to study the effect of mobility ratio on areas swept before and after breakthrough in fluid injection programs. Differences in mobility ratio are achieved through the proper selection of electrolytes for the invading and displaced fluids. The progress of the front is followed visually and photographed or traced onto plates (it desirrd positions before and after breakthrough. Example applications to standard flooding pattrrrls, vertically and horizontally fractured reservoirs and the in-situ combustion recovery process ore presentrtl. INTRODUCTION In water flooding, gas cycling and other fluid injection programs, the sweep efficiencies and swept areas after breakthrough are known to depend on the mobility ratio. Previous investigators have described the application of the X-ray technique, stepwise use of the poten-tiometric model and numerical procedures for studying these problems.1,3,4,6 Others have described the application of the electrolytic and gelatin models for studying sweep efficiencies at a mobility ratio near one.2,5,7,8,9 It is a purpose of this paper to describe a procedure for using the gelatin model to study swept areas at mobility ratios other than one. PROCEDURE The technique developed for gelatin model studies is composed of four phases: the construction of the model, the selection and preparation of electrolytes, the running procedure, and the recording of the swept areas. Each phase is discussed independently in order that the over-all procedure will not be confused. Construction of the Model Since some of the advantages of the gelatin model are its economy, and speed, it is desirable to have as small a model as is possihle without creating error through the inability to follow visually the progress of the colored front. For this work, it was found that a distance of 4 to 6 cm between salt bridges is convenient to use. Since the size is relatively small, it follows that the gelatin layer must be thin. For this study, 1/8 in. was used as the gelatin thickness in each case. The model was constructed on a flat 1/2-in. plastic (Lucite) base with boundaries constructed from 1/8-in. plastic strips. The well pattern to be studied was outlined with the 1/8-in. plastic strips on the base with narrow apertures (- - 2 mm) in the boundary to represent the wells. Behind each well opening, a rectangular area of some 8 to 12 sq cm was outlined by additional plastic strips. The plastic strips were fastened to the base by any suitable non-conducting cement so that the boundary system was liquid tight. The electrodes were constructed from sheet copper in a fashion that would allow easy removal. In this work, it was found that by simply forming a large U-shaped clip from a strip of the copper that would slip over the boundary was satisfactory and easily removed. The electrodes should be as wide as one of the sides of the rectangular area behind the well opening. If a fractured pattern is studied, fractures inside the well pattern may be represented by strips of copper of the desired shape mounted in some easily removable fashion. The reason that apertures (or salt bridges) were used for wells instead of metallic electrodes is that the plating of the electroactive ion at the cathode and the introduction of an electroactive ion at the anode has a detrimental effect on the swept area outline if these operations \rere permitted to be carried on within the well pattern itself. The anode may be used within the well pattern

Jan 1, 1957

By A. S. Yue

Small-angle tilt boundaries have been observed in a lamellar eutectic structure. These boundaries are morphologically similar to a theoretical till boundary originally proposed by Burgers. The production of a small-angle tilt boundary in the lamellar eutectic structure is attributed to the formation of an indentation on a planar solid-liquid interface during growth. Constitutional supercooling due to the accumulation of impurity atoms ahead of the interface is primarily responsible for the generation of an indentation. The distance between two faults of like sign, designated as lamellar fault distance, is calculated by the Burgers equation for small-angle boundaries. It was found that the lamellar fault distance decreases exponentially and the tilt angle increases exponentially with freezing rate. SMALL-ANGLE tilt boundaries have been observed in many crystals in the as-grown states by etching techniques. However, a detailed substantial proof for revealing the presence of dislocations in the form of etch-pits was recently accomplished by Vogel. These boundaries are described as an array of dislocations of like sign. The angle of tilt associated with a boundary is treated theoretically by Burgers3 and is given by 0 = b/D for small tilt-angle where b is the Burgers vector of the dislocations and D is their average spacing. During the course of experimentation on the solidi fication of the lamellar Mg-32 wt pct Al eutectic a microstructure which was strikingly similar to a dislocation tilt boundary was observed. An example of the type of microstructure is given in Fig. 1, which shows a combination of transverse and top sections of the lamellar eutectic structure. The lamellae of the top section on one side of the apparent tilt angle are not parallel with those on the other side. Consequently, some lamellae must be terminated somewhere. Fig. 1 shows that the termination of lamellae is analogous to a dislocation tilt boundary in a crystal lattice originally proposed by Burgers. This work represents a closer look at such structures. The factors governing the production of the small-angle tilt boundary are discussed in terms of the freezing condition and impurity distribution in the melt. The effect of freezing rate on the distance between two faults, designated as lamellar fault distance, and the tilt angle is also described. In addition, the lamellar fault distance is determined by means of the Burgers equation for small-angle tilt boundary. EXPERIMENTAL PROCEDURE The slightly impure Mg-32 wt pct Al eutectic rods, 5/8 in. in diam and 12 in. long, were made from 99.99 wt pct Al and 99.98 wt pct Mg and were cast in a high-purity graphite mold. Some of these rods were purified by zone-refining the eutectic using direct-radiation helical-coil furnaces5 A molten zone about 2 in. long was passed through the cast rods at a speed of 5.3 x 104 cm per sec for ten passes of the molten zone. Before the freezing experiment was begun, 2-1/2 in. of the material from the head and tail ends of the zone-refined eutectic were removed from the rod to eliminate any impurity. The freezing experiments were carried out under controlled conditions,8 using a protective atmosphere of purified argon. At the end of each run, observation of the tilt boundary was made throughout the entire length of the rod with a light microscope on the top, longitudinal, and transverse sections (three mutually perpendicular sections) of the lamellar eutectic solid. The experimental data used for the determination of interlamellar spacing and tilt angle were taken from the middle portion of

Jan 1, 1964

By Y. J. Wang

A critical path approach is presented for the problem of mine ventilation networks where regulators and fans are employed to control the airflow distribution. The problem is a classic one arising in mine ventilation planning. By identifying the analogy between the network for controlled flow and that for critical path method (CPM), the applications of the well known CPM technique to the ventilation problem become straightforward. The mathematical formulation of the problem is presented and the solutions are illustrated with examples. The cutset operation is introduced and employed for obtaining alternative solutions. The effects of booster fans on the total air power of the ventilation network are also discussed.

Jan 1, 1983

By D. L. Gardner, H. L. Barr

The following report covers the history of the development of the mine, present equipment, methods and costs of mining and milling. In addition, a description of the ore deposit is given with emphasis on the origin of the fractures, mode and types of ore occurrence, and mechanics of granite emplacement. An endeavor has been made to present a complete and accurate statement of the San Mauricio mine, the highest grade gold mine in the Philippine Islands. Credit is gratefully acknowledged to the mine staff for descriptions and details regarding their particular field of work. All analyses were made by Mr. T. A. DeVore, head chemist, San Mauricio Mining Co. Messrs. Edward Wisser, J. E. Fyfe, A. F. Skerl and W. B. Meek, geologists, have contributed geologic information and ideas, for which thanks are extended. The Executive Committee of Marsman and Co., Inc., Managers of the Company, has kindly given permission for publication. Mr. J. B. Stapler, Division Manager, Marsman and Co., has had the courtesy to read the manuscript and to give critical and helpful suggestions. Location of Area and Scope of Work San Mauricio Mining Co. controls a group of 113 claims that lie immediately north of the town of José Pafiganiban (formerly Mambulao), Camarines Norte, Luzon, P. I. (Fig. 1). Exploration work commenced in the spring of 1934; active development began in the fall of that year and has continued to the present date. Mill construction was begun Ocl,. 15, 1935, and production started March 10, 1936. Total production to June 1, 1939, is P10,499,105.15 ($5,249,552.57).

Jan 1, 1941

By D. L. Gardner, H. L. Barr

The following report covers the history of the development of the mine, present equipment, methods and costs of mining and milling. In addition, a description of the ore deposit is given with emphasis on the origin of the fractures, mode and types of ore occurrence, and mechanics of granite emplacement. An endeavor has been made to present a complete and accurate statement of the San Mauricio mine, the highest grade gold mine in the Philippine Islands. Credit is gratefully acknowledged to the mine staff for descriptions and details regarding their particular field of work. All analyses were made by Mr. T. A. DeVore, head chemist, San Mauricio Mining Co. Messrs. Edward Wisser, J. E. Fyfe, A. F. Skerl and W. B. Meek, geologists, have contributed geologic information and ideas, for which thanks are extended. The Executive Committee of Marsman and Co., Inc., Managers of the Company, has kindly given permission for publication. Mr. J. B. Stapler, Division Manager, Marsman and Co., has had the courtesy to read the manuscript and to give critical and helpful suggestions. Location of Area and Scope of Work San Mauricio Mining Co. controls a group of 113 claims that lie immediately north of the town of José Pafiganiban (formerly Mambulao), Camarines Norte, Luzon, P. I. (Fig. 1). Exploration work commenced in the spring of 1934; active development began in the fall of that year and has continued to the present date. Mill construction was begun Ocl,. 15, 1935, and production started March 10, 1936. Total production to June 1, 1939, is P10,499,105.15 ($5,249,552.57).

Jan 1, 1941

By S. J. Kidder, G. C. McCartney

THE Helen Mine, of the Algoma Steel Corporation, in the Michipicoten district, Ontario, Canada, has produced more than 6,240,290 tons of iron ore. Prior to and during World War I, 2,823,369 gross tons of brown ore were shipped, and from 1939 to the end of the 1944 season, 3,416,921 gross tons of siderite ore were produced from open-pit operations. Brief descriptions are given of the nature of the ore, the mining methods employed and the manner of treatment of the ore. Shipment of the finished product, known as Algoma sinter, is made to blast furnaces in both Canada and the United States. The iron-ore bodies-i.e., the oxide ores of the Old Helen and the siderite of the New Helen-are a part of a tabular shaped area of iron formation that extends over a length of more than 10,000 ft. and has a maximum width of 1000 ft. The ores are considered to be a product of introduction of iron-bearing material accompanied by replacement of the rocks already present. It is shown that introduction took place subsequent to the development of the major folded structures. It is believed the iron-bearing material emanated from an igneous source.

Jan 1, 1946

By Don C. Blackmar

THE production of non-ferrous secondary metals has become a large and important industry in the United States, and deals with practically every type of manufacturing concern. Its business is unique in that it generally buys from its customers as well as sells to them, whether they are individuals, cities, corporations, or the United States government. Its operations are of vital importance to the success and prosperity of many of the nation's most important manufacturers; yet there are few industries about which less is generally known by those outside it, whether concerning the magnitude of its operations or the details of its actual technique. The industry itself is to blame for this meager publicity, because its technical men have made few attempts to openly exchange ideas, in spite of the excellent examples set by the iron and steel or the copper and brass industries. Whether this is due to the ancient shroud of secrecy generally supposed to cover smelting operations, or because its technical men actually felt that the industry was too puny to be interesting, is hard to say. This paper will consider its subject in a general way, attempting to show something of the size and importance of the industry, as well as its fitness to do its work well. Attention will be called to the sound economic reasons for the handling of non-ferrous wastes by specialists, and to the often unseen losses of metals and labor which occur when manufacturers reclaim their own metallic wastes. MAGNITUDE OF THE MODERN INDUSTRY No particular thought is given to the kitchen accident whereby a ruined saucepan is sorrowfully tossed into the ash can, yet it is a fairly safe guess that within a month this saucepan, together with hundreds of its fellows, will again be in service, perhaps in an automobile crankcase, or in an electric vacuum sweeper. It is by this conversion of the useless into the useful, whether from home or large manufacturer, that the secondary tonnage is built up.

Jan 1, 1928

By Max Mason

IN 1923 a Western mining company was experimenting with the device of an inventor designed to locate buried ores by radio. Because the progress was slow and the results were confusing, the company began to doubt the usefulness of the method and invited me to review the whole question of the application of physics to ore detection. I was fortunate in securing the cooperation of several physicists who had worked with me during the war on the problem of submarine detection. This group has been increased and has been studying the problem of physical exploration for ores since that time. It was evident that the problem is a big one, with many angles of approach. Its general features may be set down, in rough outline, as follows: The soils, rocks and ores hidden beneath the surface differ one from another in many respects. These differences may be made to furnish a clew for the physicists working from the surface. To bring these differences into action the physicist creates some kind of an effect which penetrates into the ground and is distorted and reflected when it meets boundaries between different sorts of underground structure. In other words, he sends a message down, and the rocks and ore send back signals in reply. In picturing this process, we should not regard the ground as dense and impenetrable. The kind of messages used pass through the earth about as readily as a sound wave travels the air. If, then, the fundamental procedure is to shout down questions in the hope that an orebody will hear and answer back to us, it is clear that a large part of the expert's study must relate to the kind of questions best suited to the temperament and intelligence of orebodies. It will be easier for the ore to reply to some of our questions than to others, and it is for us to find the right questions. In certain cases, we are spared the necessity of using a messenger; because nature has already provided one. For example, we already have a terrestrial magnetic field which auto-matically and continually conveys messages from underneath. We also have available the earth's gravitational field. which furnishes us

Jan 1, 1927

By J. A. Hren, G. Thomas

A high-temperature stage has been used to study precipitation and dissolution in thin foils of Al-20pct Ag alloy directly in the electron microscope. The results show that the aging characteristics are similar to those observed for bulk materials, and in addition, direct evidence is presented for clustering at the solid solution temperature. The limit of solubility of G. P. zones is-350°C. The heterogeneous precipitation, the growth and dissolution of ?&apos;have been studied in detail. Growth of ?&apos; parallel to the basal planes, occurs by continuous motion of inter -facial partial dislocations. Growth stops at intersecting particles due to formation of sessile a/6 <110> interfacial dislocations. Growth normal to the habit plane occurs by the spontaneous nucleation of partial dislocations on alternate (111) planes and the thickening rate is --10-3= times the lengthening rate. The precipitates dissolve in layers and the final product is a whole a/2 <110> dislocation . The nucleation -growth -dissolution processes are thus completely reversible. Kinetic data obtained from the dissolution rates of ?&apos;particles enable the diffusion coefficient to be determined and the activation energy is found to be 37.5(±4) kcal mol-1, which is that expected for dzffusion of silver in aluminum. The velocity of the interfacial dislocations is thus dependent solely on the rate of diffusion of silver atoms. RECENTLY it was demonstrated that a high-temperature stage could be effectively used in the electron microscope to follow directly the processes of precipitation and dissolution in thin foils of A1-4 pct Cu alloy.&apos; These experiments also provided kinetic data which enabled the diffusion coefficient to be estimated. This new development of electron metallography opens up many fruitful areas of research and it was decided to investigate the aging behavior in thin foils of A1-20 pct Ag alloy, particularly the mechanism of heterogeneous precipitation (i.e., precipitation on lattice defects). This system was chosen because the aging characteristics of bulk specimens are now well known,2"7 and because we wished to obtain more details of the role played by partial dislocations and stacking faults in the nucleation growth and dissolution of the hcp ?&apos; phase. This is of interest for the general case of fcc-- hcp transformations. Part of the A1-Ag phase diagram is shown in Fig. 1. The use of a high-temperature stage also enables a study to be made of the clustering process (formation of G. P. zones) and to determine the structure of the solid solution prior to the usual quenching and aging procedures. It is also possible to obtain kinetic data from measurements of the rates of dissolution of precipitate particles. Unlike the results of previous experiments on A1-4 pct CU 1 where much of the initial precipitation occurred on the foil surfaces, the results on the A1-20 pct A1 alloy were identical to those reported for bulk specimens6,7 and no surface precipitation was ever observed. Thus, it was possible to follow the aging sequence: G.P. zones — ?&apos; — ? directly in the thin foils. This paper is concerned with the formation and dissolution of zones and the ?&apos; phase, and no attempt has been made so far to follow the mode of discontinuous precipitation of ?. I) EXPERIMENTAL DETAILS The high-purity A1-20 pct Ag alloy was prepared by the Aluminum Co. of America in the form of 0.001-in.-thick sheets. These were cold rolled with intermediate anneals to a thickness of 0.0004 in.,

Jan 1, 1963