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By G. C. Bernard, L. W. Bernard, L. W. Holm, W. L. Jacobs

The effect of loam on the permeability of porous media to water was studied as a {unction of foaming agent concentration, specific permeability, pressure gradient, length of a porous medium and its oil saturation. At a given fluid saturation in a porous medium, the permeability to water was found to be the same whether loam was present or not. Foam decreases the permeability to water by developing a higher trapped gas saturation than that obtained by water flooding without loam present, increasing the concentration of foaming agent increased the trapped gas saturation and thereby decreased the permeability to water. The presence of oil reduced the capability of most foaming agents to decrease the permeability of a porous medium to water. A few surfactants were found to be effective loaming agents even in the presence of oil. These results are similar to those reported in a previous paper on the effect of loam on the permeability of porous media to gas. The effect of loam was found to persist in long porous media at moderately high reservoir temperatures and during the passage of many pore volumes of surfactant-free water. INTRODUCTION This paper describes part of a study on a novel approach in the use of surfactants for oil recovery; the use of foam rather than water to displace oil. Previously it was found that foam can displace oil which normally is not displaced by water.4 The foam is formed by successively injecting a suitable surfactant solution and gas into a porous medium. Foam appears to have at least two uses in the field: (1) it shows promise as a superior oil recovery agent, and (2) it shows promise as a selective permeability reducing agent. Foam may be very useful in water floods, or in other oil recovery processes, where highly permeable streaks or unfavorable mobility ratios are a problem. A previous paper reported the effect of foam on the permeability of porous media to gas.1 In the present study the effect of foam on the permeability of porous media to water is reported. The specific objectives of the study were to determine: (1) the effect of foam on the permeability to water in porous media of various specific permeabilities, (2) the effect of foam on the permeability to water in the presence of oil, (3) the effect of foam and crude oil on the trapped gas saturation, (4) the effect of foam on permeability to water at trapped gas saturation, (5) the effect of pressure gradient on the permeability to water under foaming conditions, (6) the persistence of foam during the passage of surfactant-free water through the porous medium, and (7) the effect of various foaming agents, length of the porous medium and temperature on the permeability reduction caused by foam. EXPERIMENTAL PROCEDURES EQUIPMENT AND MATERIALS The experimental apparatus consisted of consolidated and unco n soli dated porous media, wet test meters and constant delivery pumps. The porous media consisted of consolidated sandstone cores (6 to 36 in. long), and unconsolidated sand packs (3 to 30 ft long). The consolidated cores had permeabilities of 32 and 1,000 md and porosities of about 20 per cent. The sand packs had permeabilities of 3,500 to 211,000 md and porosities of about 40 per cent. (Throughout this report a term such as 100 md sand" is used. This term means that the porous medium had a dry, nitrogen permeability of 100 md.) Fluids used in the experiments were distilled water, 1 per cent NaCl solution, aqueous solutions of foaming agents, nitrogen gas, air and crude oil.

Jan 1, 1966

By E. T. Dumble

In the Bosquejo Geoldgico de Mexico, published in 1897 by the Secretaria de Fomento as Nos. 4, 5 and 6 of the Boletin del Institute Geologico de Mexico, the Director, Jose C. Aguilera, after a detailed account of the geological observations made by himself and his assistants on their several trips through the various districts of the Republic, gives in Part 2 a synopsis of the geology of Mexico, describing . al1 the formations recognized, the rocks comprised in them, their geographical distribution, disturbances, principal eruptions and economic features, as explanatory of the Geological Map of Mexico. In Part 3 Prof. Ordonez describes many of the interesting eruptive rocks of Mexico." This work brings together in a very satisfactory way about all of the published results of geological investigations in Mexico; and although the determinations of the authors with reference to some of the sedimentary deposits are very different from those of other writers, they seem to be based upon good paleontological grounds in each instance. From the map and the text of this paper it appears that the condition of knowledge in regard to the geology of the State of Sonora, at the time of its publication, was about as follows: The western portion of the State, lying between the coast line of the Gulf of California and the foot-hills of the Sierra Madre mountains, is largely Quaternary, interrupted by areas of Azoic rocks and of later eruptives, with two or three limited exposures of limestones of the Cretaceous; while the eastern or

Jan 1, 1900

By B. A. Wilcox, A. H. Clauer

The tensile and creep deformation characteristics of fiber reinforced composites have been studied, primarily at room temperature. The matrix was an alloy of Mg-14 wt pct Li-1 wt pct Al (LA141A alloy) and the reinforcing fiber consisted of continuous wires of a high strength precipitation hardening stainless steel (AFC-77 alloy). The ultimate tensile strength and strength-to-density ratio of composites were much improved over that of the mmix, both at room ternperatwe and up to 200°C. Creep studies at room temperature revealed logarithmic weep behavior for wires and composites and steady state creep for the nonreinforced matrix. It was concluded that creep of the fibers controlled composite creep. The instantaneous logarithmic weep rate of the composite, 6, was related to the average tensile stress on the fibers, where n = 3.4. Mg-Li alloys are the lightest structural metals commercially available, e.g., the alloy LA141A (Mg-14 wt pct Li-1 wt pct Al) is 27 pct less dense than beryllium Although Mg-Li alloys have moderate tensile strengths at normal strain rates and ambient temperature, their creep strength is relatively poor, even at room temperature. Reinforcement by fibers offers a means of increasing the tensile strength as well as overcoming the limitations of low creep strength. With a proper choice of reinforcing filament, composites could be designed with higher strength-to-density and modulus-to-density ratios than the matrix alloy. This communication reports a study on the tensile and creep characteristics of alloy LA141A reinforced with continuous wires of a high-strength precipitation hardening stainless steel (AFC-77 alloy). The matrix has a bcc structure, with possible precipitates of AlLi and MgLi2A1,3 and is ductile at room temperature Stainless steel wire was chosen as the -reinforcing filament since previous work at Battelle4 showed that a good bond between wire and matrix could be produced in this system. For all volume fractions of reinforcing wire, the theoretical composite strength-to-density ratio is greater than that of the matrix and the modulus-to-density ratio is somewhat lower than that of the matrix. EXPERIMENTAL PROCEDURES The 0.004-in. diam AFC-77 wire was obtained from two suppliers: National-Standard Co.* and Crucible 0.13 Si, 0.18 V, 0.011 P, 0.012 S, balance Fe. In the as-received condition, wires from both sources had room-temperature ultimate tensile strengths of 585,000 to 590,000 psi with approximately 2 pct total elongation and 40 pct reduction in area. Composite preparation was accomplished by the vacuum infiltration technique. This involved placing the continuous wires in a mild steel tube (1/8-in. ID), capping one end of the tube with a sheet of the matrix alloy, and evacuating the other end of the tube. When the capped end was placed in a crucible of the molten matrix alloy and held for 31/2 min at 70O°C, the liquid metal was drawn up the tube approximately 7 to 8 in. A cross-sectional view of a typical composite is shown in Fig. 1. This preparation technique promoted excellent bonding between the matrix and wires, and porosity was rarely observed. Test specimens for both creep and tension studies were prepared by machining off the steel tube. Tensile tests on the wires and composite specimens were made in an Instron using a cross-head speed of 0.01 in. per min. The composite specimens had no reduced section and were held in self-tightening grooved serrated grips. Most of the specimens broke in the effective 1-in. gage section. Even though several tests fractured in the grip section, their ultimate strengths were essentially the same as those of specimens which fractured in the gage section. Creep specimens of the composite were gripped in a similar manner, and

Jan 1, 1970

By S. Wallden, R. Lindstrom

The electrolytic copper refining process is an excellent method for producing high-purity metal for electric conductors and other demanding applications. However, the process involves very high capital expenditure, especially the amounts of metals bound in the process. Efforts have therefore been made for many years to increase the production rate by increasing the current density, without impairing the quality of the copper. One of the approaches has been to diminish the polarization by mechanical means, while another was to "polish" the cathode surface by periodic brief reversals of the current. Reversed current electrolysis was first developed for electro- plating purposes and in 1952 Boliden AB and the Dept. of Electrochemistry at the Royal Inst. of Tech., Stockholm tested the method for copper refining with good results. However, no suitable electrical equipment for current reversal was then available. The thyristor-controlled silicon rectifier became available during the '60s and provided the scope for industrial application of the process and the first large-scale development was made by the Bulgarian copper refinery in Pirdop. Many copper refineries are now studying or adapting the reverse current process. Further lab and pilot investigations have been carried out at Boliden AB during the past 4 years and these were mainly aimed at studying the optimization of factors influencing the quality of copper. A production unit containing two tank sections with a total of 56 cells and equipped with a rectifier for cur- rent reversal has been installed and will be started during 1973.

Jan 1, 1973

By R. J. Wasilewski

Axial expansion has been determined by X-ray diffraction up to 600° to 760°C in a titanium and four high-oxygen alloys. Expansion data cannot be fitted to the usual quadratic expression and anomalies observed are believed indicative of the changes in the bonding configuration of the valence electrons. Furthermore, there is significant disagreement between data obtained on poly crystalline and single crystal powder specimens. The major disagreement occurs within the temperature range (-470°C) where both mechanical and electrical properties also show markedly anomalous behavior. X. HIS work forms part of an investigation of physical properties of pure titanium and its osolid solutiono alloys with oxygen and nitrogen. In view of the anomalies observed in both the electrical resistivity' and the susceptibility behavior it was decided accurately to determine the thermal expansion behavior of the pure and alloyed a titanium. PREVIOUS WORK The axial expansion coefficients reported for pure titanium are listed below. As can be seen, there is a marked discrepancy between the axial expansion and the experimentally determined coefficients on poly crystal line material. Thus, if we take the most recently reported axial expansivities3,4 we obtain perature interval of 25o to 700°C. The experimental value reported for polycrystalline metal is, however, of the order of 9.7 x 10o6 per OC. EXPERIMENTAL I) Pure Titanium. High purity titanium powder of -325 mesh was used throughout most of this work. The only significant impurities present were the interstitials, oxygen and nitrogen, which analyzed respectively 650 and 80 ppm. The purity of the ma-

Jan 1, 1962

Minerals: When man first picked up an appropriately shaped stone and fastened it to a stick of wood to create a primitive axe or hammer he started down the long road of mineral dependency that has continued until today (Fig. 2). Though he did not realize it, that man and his stone axe created an extremely simple form of mineral economy. The struggle against extinction from that day has been fought with minerals. In addition to providing himself with a means to fight for survival, he also exhibited an increase in intelligence. As his curiosity was stimulated, his ability increased to provide himself with better mineral and metal weapons and tools. Today, when we examine the artifacts of past civilizations, we measure the degree of development that had been attained by the variety of metals and minerals possessed and how they were used. The metals employed are so characteristic of the level of intelligence that we have named the various stages of human progress by the metals that were most commonly utilized. Thus, mall went through the Stone Age, the 13ronze Age, the Iron Age and now has reached the Steel Age. The first period of mineral development, the Stone 4ge, began during late Pliocene time. In this first mineral age, prehistoric man began to shape stones by chip- ping off small pieces until the stone assumed the crude form he wanted. As his intelligence increased, he progressed to finer workmanship and turned out finished spear heads and barbed arrows. Throughout this very

Jan 1, 1950

By D. Hawington

HEALTH and safety in the mining and allied industries of the United States have unquestionably been progressing, particularly during the past three or four years, even though the progress has been anything but great in some branches of these industries. Statistical data to support this statement are readily available as to safety, but similar health data are unfortunately not available. In coal mining the rate of occurrence of fatal accidents per million tons of coal produced for the ten-year period 1911.20 inclusive was 4.27; this rate was 3.84 in 1930, .3.31 in 1931, 3.36 in 1932, and 2.69 (tentative) in 1933. In metal mining, the-rate of occurrence of fatal and- non-fatal injuries per .thousand 300-day workers (calculated) was 224.36 for- the same ten-year period. This fell slowly until after 1929 when it was 203.14, dropping to 170.78 in 1930, to 142.09 in 1931, to 138.46 in 1932, and to 155.13 in 1933. Here, again,-the real progress began in 1931 though the rate in 1930 was not particularly bad. For the same ten-year period, the rate of those killed and injured: in: quarrying per thousand 300-day workers (calculated)

Jan 1, 1935

Geological and Natural History Survey of Wisconsin, The University of Wisconsin, Madison, Wis - E. F Bean, State Geologist. A complete list of publications of this Survey will be sent upon request Only a portion of the Bulletins and Maps fall within the scope of this directory, and most of them are available They are: Bulletin 4, Building and ornamental stones of Wisconsin (1898), $2 50, 6, Preliminary report on the copper-bearing rocks of Douglas County, and parts of Washburn and Bayfield counties (1901), 50 cents, 7, The clays and clay industries of Wisconsin (pt 1) (1901), 50 cents; 14, Report on lead and zinc deposits of Wisconsin (the report is out of print but the 18 maps which accompanied it can still be had) (1906), 20 cents (a series of six maps, supplementary to these (1909), may be had for 6 cents), 15, The clays of Wisconsin and their uses (1906), 50 cents; 16, The geology of north-central Wisconsin (1907), $2, 17, The abandoned shore lines of eastern Wisconsin (1907), 50 cents, 19, Zinc and lead deposits of the Upper Mississippi Valley (1907), 25 cents; 34, The limestone road materials of Wisconsin (1914), 50 cents, 35, Underground and surface water supplies of Wisconsin (1915), $150, 36, The physiography of Wisconsin (new edition now in press) (1916), $125, 41, A study of methods of mine assessments and valuation (1914), 50 cents; 44, Mineral land classification in parts of northwestern Wisconsin (1915), $5, 45, The peat resources of Wisconsin (1915), 50 cents, 46, Mineral

Jan 1, 1933

By A. Vifian, I. lwasaki

Several samples of copper-nickel ore from the Duluth Gabbro were studied to relate their mineral-ogical characteristics with their amenability to concentration by flotation. The most common rocks in the samples were norites, gabbros, and troctolites. The texture of the rocks varied from coarse pegma-titic to very fine. The copper contents ranged from 0.2-0.7% and the nickel contents from 0.07-0.15%. The ore minerals were chalcopyrite, cubanite, pyrrhotite, and pentlandite. Most of the ore minerals occurred in interstices between laths of plagioclase, but some were included in the gangue grains. The samples responded readily to xanthate flotation. After a 65 to 100-mesh grind about 95% of the copper and 85% of the nickel were recovered in a bulk sulfide concentrate. Such recoveries remained constant even with grinds as fine as 270 mesh due to the extremely fine inclusions of sulfides in the silicate gangue. A finer grind than 270 mesh was necessary to free the copper-iron sulfides from the nickel-iron sulfides. A combination of time and British gum* was quite effective in producing concentrates analyzing 25-30% copper. The nickel concentrate averaged 1.5% nickel. Most of the nickel lost in the tailing was present as un-liberated sulfides and not as nickel in the olivine structure. The nickel content of the olivine was only about 0.05 or 0.08%. Western world nickel usage in 1967 is expected to be the second highest on record, amounting to 825 million lb. Despite a rise in mine production, however, demand is expected to exceed supply in 1968. ' Hence, exploration, development, and production expansion projects are being accelerated on a world scale. In Minnesota the copper-nickel bearing Duluth Gabbro is receiving much attention. During the past year 11 companies have been granted leases in the region, and the 1967 Minnesota legislature enacted a tax law designed to encourage the development of a copper-nickel industry. Although it is only during the past few years that mining companies have shown an active interest in the Minnesota copper-nickel deposit, copper-nickel minerals have been known to exist in northeastern Minnesota since 1899.3 At the 28th Mining Symposium, Dr. P. K. Sims, from the Geological Survey of Minnesota, gave a review of copper-nickel exploration in northeastern Minnesota,4 in which he emphasized that the potential of the Duluth Gabbro complex is large. Tests on samples from the Kawishiwi River area were reported by the United States Bureau of Mines in 1955.' In 1964, the Mines Experiment Station described tests on samples from the Gunflint Trail: and in 1966 the Minnesota Geological Survey published a geological map of the Gabbro Lake Quadrangle. The Mines Experiment Station published a study of the concentration of a Minnesota copper-nickel ore in 1967.7 The present paper is divided into three parts. The first describes the mineralogy of some rock samples from the Kawishiwi River area of northeastern Minnesota; the second summarizes the results of numerous flotation tests that were made on the samples, and the third explains the loss of nickel in the flotation tailing. MINERALOGY OF KAWlSHlWl ROCKS Recently five samples of mineralized gabbro from the Kawishiwi River area, a few miles east of Ely, were received at the Mines Experiment Station. One of the samples was a 175-lb composite, which was designated Ore 1556. The other four samples were 7-lb grab samples that had been obtained from four different exploration pits. They were designated Ore 1626, Lots 1 through 4. Basic Mineralogy: Many authors have reported that the rocks of the so-called gabbro of the Duluth Intrusion vary widely in composition.8-9 The samples on which our studies were based also contained a wide range of rocks. A gabbro, olivine-gabbro, anorthosite-gabbro, norite, and a troctolite were represented. The essential minerals in the samples were plagio-clase, pyroxene, and olivine, in variable proportions.

Jan 1, 1969

By J. H. Anderson, G. A. Parks, B. K. Jindal

Both temperature and humidity are important variables in electrical separations. By independent control of temperature and water vapor pressure, it is shown that charge depends primarily upon relative humidity, not on temperature or water pressure alone. All the effects of temperature changes other than modification of humidity are apparently small. However, humidity control can be achieved through manipulation of the more tractable variable, temperature. Both temperature and humidity are important variables in electrical separations. Some of their effects have been described in general by Fraas1,2 and by Ralston.3 The influence of temperature and humidity may be considered a problem in industrial separations because humidity, especially, is not normally controlled, hence leads to unpredicted quality control problems. The problem is significant whether the separation is based on conductivity differences or on contact electrification. There is no doubt that water adsorbs from humid atmospheres onto mineral surfaces resulting in conductivity changes.'-8 An empirical relationship between conductivity and humidity is1.4-6,8 where a and b are constants peculiar to the substrate, and s and h are the conductivity and relative humidity respectively. Some authors have taken advantage of differences in a and b among minerals to make or propose electrodynamic separations in which h is the key control variable. Fraasl,2 reported that the charge developed on quartz and feldspar through contact with aluminum is sensitive to humidity, as illustrated schematically in Fig. 1. Lawver9 found that the charge developed by quartz on contact with several materials was tem-

Jan 1, 1967

NAME AND OBJECT. SEc. 1. This Institute is incorporated under the Membership Corporations law of the State of New York ; its corporate name is American Institute of Mining Engineers; and its objects are such as are stated in its Certificate of Incorporation. ARTICLE II. MEMBERS. SEC. 1. The membership of the Institute shall comprise four classes, namely 1. Members ; 2. Honorary Members ; 3. Associates ; 4. Junior Members. All members shall be equally entitled to the privileges of membership, except¬ing that Honorary Members, Junior Members, and Members and Associates whose residences shall be outside of the United States, Mexico, and Canada shall not be entitled to vote. Members and Associates residing within the United States of America, Mexico, and Canada, and not in arrears for dues, shall be entitled to vote in person at the meetings of the Institute, or, as hereinafter provided for, by letter ballot. SEC. 2. The following classes of persons shall be eligible for membership in the Institute, namely : as Members, all professional mining . engineers, geologists, metallurgists, or chemists, and all persons actively engaged in mining and metal¬lurgical engineering, geology, or chemistry ; as Associates, all persons desirous of being connected with the Institute who in the opinion of the Board of Directors are suitable.

Jan 1, 1923

In the Philippines, where distances are spoken of in terms off fight time, the Sipalay copper mines are two flight hours southeast of Manila on the island of Negros. After landing at the airport in Bacolod, it is then 170 km (106 milers) by surface transportation to Marinduque Mining and Industrial Corp.'s expanding copper operation. While copper deposits were discovered in the area in 1936-and one mine, the Binulig, began operations soon after-it wasn't until 1956 that stripping at Sipalay and construction of a 4000-t/d (4400-stpd) mill began. The mill went into operation in May 1957, and the first shipment of copper concentrate was made three months later.

Jan 8, 1978

NAME AND OBJECT. SEc. 1. This Institute is incorporated under the Membership Corporations law of the State of New York ; its corporate name is American Institute of Mining Engineers; and its objects are such as are stated in its Certificate of Incorporation. ARTICLE II. MEMBERS. SEC. 1. The membership of the Institute shall comprise four classes, namely 1. Members ; 2. Honorary Members ; 3. Associates ; 4. Junior Members. All members shall be equally entitled to the privileges of membership, except¬ing that Honorary Members, Junior Members, and Members and Associates whose residences shall be outside of the United States, Mexico, and Canada shall not be entitled to vote. Members and Associates residing within the United States of America, Mexico, and Canada, and not in arrears for dues, shall be entitled to vote in person at the meetings of the Institute, or, as hereinafter provided for, by letter ballot. SEC. 2. The following classes of persons shall be eligible for membership in the Institute, namely : as Members, all professional mining . engineers, geologists, metallurgists, or chemists, and all persons actively engaged in mining and metal¬lurgical engineering, geology, or chemistry ; as Associates, all persons desirous of being connected with the Institute who in the opinion of the Board of Directors are suitable.

Jan 1, 1923

By Mason K. Banks

A process has been developed which produces spodumene concentrates assaying 6.0 pct Li2O and 0.45 pct Fe2O3, with 70 to 75 pct recovery of spodumene. Two flotation separations are required: the simultaneous removal of mica, feldspar, and quartz as a froth product using a cationic collector, and the subsequent removal of iron-bearing minerals as a froth product while spodumene is depressed as a tailing. SINCE the close of World War II there have been numerous developments resulting in the increased use of lithium by industry. Notable among these has been the development of an industrial lubricant, based on lithium stearate, which is fluid at low temperatures, stable at high temperature, and insoluble in water. A new bleaching agent, lithium hypo-chlorite, has also been developed recently.' Other well-known uses are listed below: 1—Lithium oxide in ceramics reduces firing time, lowers melting temperatures, lowers thermal expansion, raises refractive index, and improves chemical resistivity. 2—Lithium carbonate and lithium strontium nitrate are used in pyrotechnics for their brilliant red color.' 3—Lithium chlorides and fluorides are used as fluxes for welding aluminum and magnesium.' 4—The affinity of lithium for nitrogen is the basis for a process used in purifying helium." 5— Lithium chlorides and bromides are used in air conditioning for their powers to absorb organic amines, ammonia, and smoke.6-—Lithium hydride has been used as a source of hydrogen to inflate life rafts and balloons used by the Air Forces and Navy.' 7— Lithium metal and lithium hydride are useful in the atomic energy program in connection with the production of the isotopes of hydrogen." During the 1942-45 period of World War 11, Solvay Process Co. operated a flotation plant with a daily capacity of 300 tons of ore for the production of spodumene concentrate near Kings Mountain, North Carolina. The operation was shut down upon reduction of wartime demand for lithium chemicals, and until recently there has been no production from the Carolinas. In April 1950 an investigation of the problem of spodumene flotation from North Carolina ores was begun at North Carolina State College Minerals Research Laboratory at Asheville, N. C. This laboratory, operating under the combined auspices of North Carolina State College, North Carolina Department of Conservation and Development, and the Tennessee Valley Authority, undertook the spodumene project at the request of Foote Mineral Co. of Philadelphia. The work, involving a period of 15 months of intensive batch and pilot plant investigation, was completed in June 1951 and resulted in development of a process for concentration of spodumene by flotation which has been hereto unrecorded in the literature. A similar approach has been used before on iron, ilmenite, and other minerals, but the literature shows no record of its having been applied to spodumene. Parts of the process are now being used on a commercial scale at the Foote Mineral Co. plant near Kings Mountain, N. C., which has been in production since July 1951. It is the purpose of this paper to describe some of the results of the investigation. The Orebodies Spodumene-bearing pegmatites occur in a narrow belt 24.5 miles long and 1.8 miles wide extending southwestward from Lincolnton to Grover, N. C. According to statements judged to be conservative, the tin-spodumene belt of the Carolinas contains an estimated 4,300,000 tons of pegmatite ore averaging 15 pct spodumene. This amounts to "a reserve of at least 650,000 tons of spodumene (more than 20,000 tons of metallic lithium) to a depth of 100 ft."' This figure includes only bodies having an average thickness of 35 ft and length of 550 ft. There are hundreds of pegmatites in the belt, many of which are less than 10 ft wide. The largest pegmatite in the area has a maximum thickness of 395 ft and maximum length of 3250 ft.' These larger pegmatites are composed principally

Jan 1, 1954

By W. A. Backofen, D. H. Avery, W. F. Hosford

Sheets of the magnesium alloys AZ31B, HK31A, and ZE10A in several different tempers were tested in tension and determinations were made of the ratio of width-to-thickness strain. A marked increase in the ratio with tensile straining and a dependence upon alloy and test direction are rationalized in terms of a balance between the amounts of basal and prism-plane slip. All such variations are related, in turn, to the prevailing crystallographic texture. Fracture appearance is explained on the basis of anisotropy in plastic flow, and implications for developing texture -hardening effects in these alloys are discussed. ThE crystallographic texture or preferred orientation of a given material is determined by details of processing history. Such texture is known to influence many aspects of material behavior, in particular both the yielding and strain-hardening characteristics which are of special interest in the present work. Traditionally, the resulting plastic anisotropy has not been regarded as especially desirable. Earing in drawn sheet is perhaps the most common example of an unwanted effect of texture. However, it has also been recognized that suitable textures may be usefully employed to improve drawability,1,2 as a specific example, and generally to control yielding resistance under combined-stress loading.374 Texture would seem to be a detail of structure not yet exploited to nearly the fullest extent. A convenient basis for characterizing anisotropy in plastic behavior is the ratio of width-to-thickness strains obtained in a tension test;5&apos;6 the parameter is frequently labeled "R" and its value is revealing with respect to the nature of the prevailing texture. R gives a useful measure of a material&apos;s "thinning resistance". For an isotropic material, R = 1. With R > 1 the increased through-thickness strength in a sheet means greater resistance to yielding under biaxial tension, or "texture hardening";3&apos;4 if R < 1 the result may be a "texture softening" under the same loading conditions.4 Most R data relate to steel sheets for deep-drawing applications. Values for steel and other materials of cubic structures are not often much greater than 1 and nearly constant with strain in testing.1,2,7,8 To explore the implications of plastic anisotropy further, it was felt that experiments with much more strongly textured materials would be useful, and this led to the choice of magnesium alloys. The "ideal" sheet texture for magnesium contains the (0001) plane in the rolling plane, which ought to lead to R values approaching infinity. However, departures from the ideal texture, the possibility of slip in non-close-packed directions, and deformation by twinning would all be expected to introduce some range of R. Accordingly, studies on these materials were undertaken. EXPERIMENTAL Alloys in sheet form, Table I, were selected to obtain a variation in crystallographic texture, in the expectation that this would be reflected in differences in plastic anisotropy. Pole figures constructed by the Schulz surface-reflection technique9 were provided with the experimental materials by the Dow Metal Products Co. Profiles of pole density along great circles through the rolling (0 deg) and transverse (90 deg) directions were prepared from the pole figures and are collected in Figs. 1 and 2; considerable departure from the "ideal" (0001) alignment in the rolling plane is evident, with the largest angular spread in both directions being found in the ZEl0 alloy. Results of tensile tests on full-thickness specimens of 6-in. gage length by 1/2-in. width are given in Fig. 3 as engineering stress-strain curves* in rolling and transverse directions. All tests but one were made at a constant drive rate of 0.02 in. per min, and the final values of percent elongation at fracture, over the initial 6-in. gage length, are noted at the ends of the curves; one test on ZE10A-

Jan 1, 1965

By E. D. McMurry

INTRODUCTION Before discussing the use of the free piston; it may be well to explain briefly the type of gas lift valves with which the loo] is designed to function. The gas lift valve ii nothing more or less than a small back pressure regulator. It; construction consists of an outer hous ing covering a seamless metallic bellows in such a way as in form a sealed pressure vessel or pressure dome. To the bellow* in attached a stem and to this stem is attached a .rating member. When the valve is run into the hole, a pre-delermined pressure charge is placed in the pressure dome. As shown in Fig. 1. the valve is furnished in four different major assem-blies. to accomplish good results in different types of wells. The valve is mounted on a pup joint (Fig. 2a) : the eoin-plele assembly is entered into the tubing siring at the desired location. Each valve is furnished with a revere flow check valve (Fig. 2-b) to eliminate any back wash through the mechanism. Valve action is as follows: At any time the casing pressure is allowed to exceed the pressure forces within the pressure dome of the valve, the valve simply opens and passes gas from the rasing annulus into the tubing. When the casing pressure forces arc allowed to bleed to a force less than the pressure force within the dome, of the valve. the valve closes. With this type of construction. it is possible to open and close the valve or valves at will from the surface, the medium of the gas pressure in the rasing annnlus. The cycle of operation is governed by a tine cycle motor valve, commonly referred to as a gas lift interutitter or gas life surfacr controller (Fig. 3). In actual practice. after the well is unloaded only one valve is in operation . . . all other valve.: remain in the closed position. On pre-determined time cycles, it is possible to open and close this operating valve at will, and to pass the desired amount of gas through this valve wheneler needed. This method of gas lift is widelv used and has been found In be very efficient. However, it has long been known that even greater efficiency would be obtained if it were possible to place Piston between the injected gas and the fluid head. The free piston which will be discussed here was designed to accomplish this end and has been found to do so with very satisfactory results. DESIGN AND OPERATION OF THE FREE PISTON Basically. the free piston consist- of a telescoping assembly in which are incorporated the various control and operating parts (Fig. A set of sleeve valves which are opened and closed by movement of the telescoping section is contained in the. tool. A cross section of the free piston is shown in Fig. 4-11, &apos;rile main body cotain- a seamless monel bellows of the same type as that generally used in pressure charged gas lift valves (Fig. 4-c), and a valve core to permit placing a pressure charge in the bellows before the free piston is placed in service. The bellows is the main control unit of the free piston and performs two function: 1. It governs the opening and closing of the sleeve valves. a.: dictated by the producing activities of the well in which the piston is operating. 2. In its normal position, it holds a rubber packer in an elongated position to permit passage of fluid between the packer and the tubing walls. The lower section of the free piston contains a hydraulic shock absorber which cushions the return of the tool to its

Jan 1, 1953

By L. J. Erck, T. E. Ban

A discussion of laboratory procedures used to determine pellet quality and to simulate handling and firing conditions. Strength-temperature relationships in pelletizing; effect of chemical additives on agglomeration; and crushing, abrasion, and impact resistance of the pelletized products are discussed with respect to five different iron ore concentrates. IN most routine experimental work on products and processes, method:; of operation and product evaluation are established from accurately controlled laboratory tests. With particular emphasis on the pelletization of fine iron ore concentrates, standardized procedures of laboratory production and product testing have been established at Cleveland-Cliffs Iron Co. Research Laboratory at Ishpeming, Mich. A program of this nature was used for investigating the agglomeration characteristics of various iron ore concentrates. The factors which control the process were studied and subsequently controlled for these investigations. Pelletizing as applied to iron ore agglomeration involves the preparation of spheroidal masses from a fine moist concentrate, followed by high-tempera-ture firing to produce a final product. The preparation of moist spherorids is generally designated as balling. This produces the so-called green pellets or balls. After, these have been fired they are called pellets. Balling is accomplished by rolling moist concentrates in a revolving drum until small spheroids form by a snow-balling action. These balls are then heated in a shaft furnace, or a modification of this device, to a temperature high enough to cause agglomeration within the individual balls while they descend countercurrent to hot oxidizing gases. By this process the lour strength balls are converted through various chemical and physical-chemical processes into hard pellets. With correct balling and firing, the pellets are strong, resist abrasive action and handling treatments, and provide a suitable blast furnace and open hearth feed. In 1950 Tigerschiold and Ilmoni developed a working hypothesis to explain the formation and stability of green pellets.&apos; Their work was presented on the basis of geologists&apos; discoveries concerning the soil-water system and C. V. Firth&apos;s early postulates of green pellet formation.&apos; Fundamental reactions oc-curing within fired pellets have been described by Cooke and Ban, who showed the microstructure changes caused by different firing temperatures." All these investigators have provided scientific clarifications of agglomeration by the pelletizing process and have opened avenues for greater development. Mineral grain growth and ceramic bond formation are the two basic phenomena imparting coherency to particles within a fired pellet of iron ore. Each of these is established by the transfer of thermal energy to the mineral particles. Grain growth mechanisms are chiefly physical reactions wherein smaller particles consolidate into larger ones, with resulting decrease in surface energy conforming with the second law of thermodynamics. Ceramic bond formation is a chemical reaction usually between basic and acid metallic oxides of the gangue and ore minerals. CaO, MgO, A1203, and FeO of Fe3O4, react in varying proportions with SiO, or Fe2O3, to form a great series of compounds or amorphous solid solutions. These product bond iron mineral particles together by a bridging action or by direct reaction with the surfaces of the particles. The result of the grain growth-ceramic bond formations is a consolidated, coherent compact of gangue and iron minerals formerly held together by much weaker bonds of interstitial water and forces common to dry, unconsolidated particles.4 With respect to iron ore agglomeration, these high temperature bonding reactions have been described by Schwartz, who referred to the bonds in sinters," and by Cooke and Ban, who referred to the bonds in fired pellets." The extent of the bonding phenomena and the consequent strength of fired pellets is governed by

Jan 1, 1954

By H. Biloni, B. Chalmers

Metallographic studies of the segregation of solute in and near the surfaces of chill-cast alloys have shown that, under sufficiently severe conditions, nucleation on the cold mold surface is followed by the formation of a disc of solid of the same composition as the liquid. This disc is surrounded by two concentric rings in which the concentration first decreases and then increases. The discs and rings are surrounded by a region in which arms of low solute concentration separate regions of high concentration. These arms start at the periphery of the outer ring and are initially radial; they make a gradual curved transition from the radial direction to a crystallographic direction. A normal dendritic substrcture is established beyond the position at which the arms have become crystallographically aligned. When the cooling is less severe, the disc becomes less irregular in shape and has a concentration minimum at the center. The term "Predendritic" is proposed for these transitions. A qualitative explanation is outlined for the phenomena observed at the surface and in the equiaxed region of the ingots. It is well-established1-&apos; that the normal mode of solidification for alloys under most conditions is dendritic. A characteristic of dendritic solidification is the growth of rods or plates in specific crys-tallographic directions. The remaining liquid solidifies later, usually with a higher concentration of solute than the original liquid. Very little is known, however, about the transition from a crystal nucleus until the dendritic pattern is established. It is clear that there must be a transition because the nucleus is much smaller than the characteristic spacings found in the "steady-state" structure. And it also seems clear that the initial conditions must be important since the undercooling existing during the nucleation of the grains has a remarkable influence upon the grain size4 and the segregation pattern. The present paper reports a study of the micro-segregation in regions where crystals have nucleated, and the conclusions that can be drawn regarding the early stages of growth, in connection with the details of the solidification process. Aluminum of 99.993 purity, A1-Cu alloys containing 0.5 to 20 wt pct Cu, and Pb-Sn alloys with 5 wt pct Sn were cast and examined metallographically at the as-cast surface, close to the surface, and in the interior after casting. The alloys were cast from controlled temperatures against surfaces at different temperatures ranging from room temperature to approximately the liquidus temperature of the alloy. The surfaces were, in various experiments, graphite, stainless steel, copper, and aluminum. The methods used for metallographic examination were as follows. 1) The Nomarski phase contrast interferometer6 was used to obtain information on the topography of the as-cast surface. 2) The distribution of any solute present in A1 99.993 pct and copper in the A1-Cu alloys was studied by the anodic film technique originated by Lacombe and Mouflard7 and previously applied in the study of the solidification of aluminum by Biloni.8 The electropolished surface of the specimen is anodized under controlled conditions so that the thickness of the oxide film and therefore the interference colors under white light are sensitive to the local composition. This technique was applied to the as-cast surfaces and to metallographically prepared surfaces from the interior. 3) If in Al-Cu alloys, the surface is anodically oxidized for several minutes, instead of seconds as in the color-film technique, the copper segregation is outlined by a different level with respect to the matrix. This method is less sensitive but complementary to that for the color films. 4) The distribution of copper revealed and mapped by the metallographic techniques was confirmed by electron probe. 5) In samples with high concentration of copper, evidence for the copper distribution could be seen optically after electropolishing.

Jan 1, 1965

By Lee W. Abramson

INTRODUCTION The design of rock support for underground nuclear waste repositories requires consideration of special construction and operation requirements, and of the adverse environmental conditions in which some of the support is placed. While repository layouts resemble mines, design, construction and operation are subject to quality assurance and public scrutiny similar to what is experienced for nuclear power plants. Exploration, design, construction and operation go through phases of review and licensing by government agencies as repositories evolve. This paper discusses (1) the various stages of repository development; (2) the environment that supports must be de signed for; (3) the environmental effects on support materials; and (4) alternative types of repository rock support. Much of the information presented in this paper was derived from work conducted for Basalt Waste Isolation Project. Most of the information, however, would apply to other hard rock repositories. REPOSITORY DEVELOPMENT AND THE NEED FOR ROCK SUPPORT Repository development can be characterized by five general stages: exploration and design, excavation, waste emplacement, re trievability period, and backfilling. It is helpful to understand these phases of development to see where and when rock supports are required and how the design is verified. The description that follows is simplified. Details have been omitted, and future plans may not conform to this scenario.

Jan 1, 1984

NAME AND OBJECT. SEC. 1. This Institute is incorporated under the Membership Corporations law of the State of New York ; its corporate name is American Institute of Mining Engineers; and its objects are such as are stated in its Certificate of Incorporation. ARTICLE II. MEMBERS. SEC. 1. The membership of the Institute shall comprise four classes, namely 1. Members ; 2. Honorary Members ; 3. Associates ; 4. Junior Members. All members shall be equally entitled to the privileges of membership, except¬ing that Honorary Members, Junior Members, and Members and Associates whose residences shall be outside of the United States, Mexico, and Canada shall not be entitled to vote. Members and Associates residing within the United States of America, Mexico, and Canada, and not in arrears for dues, shall be entitled to vote in person at the meetings of the Institute, or, as hereinafter provided for, by letter ballot. SEC. 2. The following classes of persons shall be eligible for membership in the Institute, namely : as Members, all professional mining . engineers, geologists, metallurgists, or chemists, and all persons actively engaged in mining and metallurgical engineering, geology, or chemistry ; as Associates, all persons desirous of being connected with the Institute who in the opinion of the Board of Directors are suitable.

Jan 1, 1923