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By W. J. Taylor

Some eight years ago I became interested to a considerable extent in one of the well-known deposits of sulphury iron ore in New Jersey, and, as a consequence, soon became interested in the subject of the elimination of the sulphur. On investigation I found that no department of pig-iron manufacture had received less attention than that of roasting or calcining ores for the elimination of sulphur, carbonic acid, water, etc. My first devices to eliminate sulphur mere naturally in the limekiln line, with solid fuel mixed with the ore, in the same way = common lime is burnt with small coal. While this process will succeed tolerably well for carbonates or calcareous ores, even though they contain sulphur as sulphates, I soon found it would not answer for our magnetites, which are very hard and dense, carrying from 2 to 5 per cent. of sulphur as pyrites, and become very sticky as soon as any attempt is made to roast them at a high heat. Some laboratory experiments developed the fact that the nearer the gaseous current surrounding the hot ore approached in composition pure atmospheric air the more rapidly the sulphur was oxidized, while in an atmosphere composed largely of carbonic oxide, carbonic acid, and nitrogen, it seemed almost impossible to reduce the sulphur more than one-half, which was a confirmation of the well-known Pact that just one-half of the sulphur in pyrites volatilizes very easily, and that the trouble is mainly to remove the remainder. It was thus apparent that the atmosphere surrounding the ore was of as much importance as the temperature..• This led to the trial of a kiln to heat the ore by conduction through the brick. It was divided into ore-chambers, which were surrounded with flues, through which the products of combustion of gaseoua fuel passed without coming in contact with the ore. We did not, however, succeed by this arrangement in getting more than a cherry-red heat, which, of course, was too low to accomplish anything. I had at this point become convinced— 1st. That gaseous fuel only would accomplish the work successfully. 2d. That since a high temperature was required to insure a rapid oxidation of the sulphur, and also to make the ore open and porous,

Jan 1, 1881

By Y. C. Liu, R. H. Richman

The effects of gel,manium and tin on the deformation and 9-e-crystallization textures of copper have been explored in detail with in the copper-rich terminal solid solutions. Addition of solute to copper produces a change in deformation texture from the copper type to the 70 :30 brass type. This transition has been measured quantitatively The types mid proportions of recrystal-lization components have been determined as a function of com-position, and correlation of recrystallization components with specific deformation components is discussed. On the basis of information available in the literature, it has been suggested that the effect of solute elements on the recrystallization texture of copper

Jan 1, 1961

By Frank Firmstone

IN 1871, two furnaces at the Glendon Iron Works, which had been blown out on account of the "coal strike," were altered from the open-top plan with side flues for collecting the gas, to closed tops with cup and cone. In one furnace the suppression of the side flues permitted a considerable alteration in the profile, but in the other (No. 5) no change in this respect was made; the side flues were simply bricked up and new ones cut through the sides close to the top. This furnace was in blast over four years, and we can, therefore, form a pretty good idea of the effect of the alterations on the furnace process. The principal dimensions are; Height 72'; greatest diameter, 18'; diameter at tuyeres, 8'; diameter of top, 10'; diameter at stock line (point at which the top of the materials is kept), 11'; cubic contents, 11,900 cubic feet. The table below shows the average results for periods of twenty-six weeks each. 1st, of the open-topped furnace; 2d, of the furnace with the first charger used, which was an ordinary cup and cone (diameter of cone 5' 2") 3d, with the charger used ever since, a "double" cone 7' 5" diameter outside, having a central opening 3' in diameter. The diagram (Plate II) shows the daily variations, in the grade of the irons for the same periods.* * In calculating the average grade of each day's iron, each twelve hours was taken by itself whenever more than two kinds of iron were made in the 24 hours, and the diagram drawn accordingly. By counting, it will be found that there were more such days with the single cone than with the "double" cone, and more with this than with the open top. † Anthracite.

Jan 1, 1876

By AIME

NEW YORK'S largest hotel, the Pennsylvania, will be filled with mining and oil men and metallurgists the third week of February when some 3000 AIME members, their wives, and guests will gather for the Institute's 1948 Annual Meeting-its 166th general meeting. Except for the usual Sunday afternoon and evening sessions of the Mineral Industry Education Division at the Columbia University Men's Faculty Club, the big assembly will be under one top and members will not this year have to consult compass and map to find their next session. Possibly enervated by the stupendous effort of the Anniversary Celebration last spring and the plethora of highly successful fall meetings, the various committees have been a trifle slow in arranging their social and technical programs, but in mid December as we go to press there is already much to report indicative of substantial fare and high interest. The definite timetable schedule will appear in the February M&M.

Jan 1, 1948

By Elwin L. Fisk

The Cordero mine is located in the Nevada portion of the Opalite Mining district that straddles the Oregon-Nevada state boundary. The mercury deposits of the district occur along the margins of the broad east-west graben valley of McDermitt Creek. The only other major producers, the Opalite and Bretz mines, on the northern margin of the graben have thus far exploited only shallow deposits within 100 feet of the surface. Through December 1965, Cordero has produced 94,680 flasks of mercury, the most of which came from the large underground cinnabar deposit. Nearly all of the mercury ore deposits in this district have been found in Miocene rhyolitic intrusives, flows, tuffs, and lake beds. These rhyolites have been argillically altered at depth and extensively silicified at or near the surface. These silicified areas or "opalite" masses were the original cinnabar-bearing outcrops.

Jan 1, 1968

By A. A. Burr, D. G. Ebeling

The effects of casting texture, grain orientation and grain size upon the performance of Alnico permanent magnets is described. Single-crystal specimens were produced by special sintering and grain coarsening techniques to study the effect of crystal orientation. In addition to texture and orientation effects, an analysis of the results indicates that the permanent magnet performance is impaired by a refinement of the grain size. AN excellent historical review of the development of Alnico permanent magnets has been prepared by Bozorth.1 The desirable permanent magnet characteristics of Fe-Ni-A1 alloys were discovered in 1932 by Mishima.2,3 The work of Ruder' showed that the alloys were age-hardenable, and Betteridge5 defined the best composition and heat treatment for the magnetically isotropic alloy known as "Alnico 3." Horsburgh and Tetley0 increased the energy product by the addition of cobalt and copper, "Alnico 2," and Oliver and Sheddon7 demonstrated that cooling in a magnetic field improved the residual induction of this alloy. Jonas8,9 then disclosed the great practical benefits of heat treating an alloy of higher cobalt content in a magnetic field and the resulting alloy, "Alnico 5," has become the standard of the industry. This paper describes the fundamental aspects of a procedure which can be used to further improve the properties of these anisotropic permanent magnet alloys. A study of the casting techniques used in the production of anisotropic Alnico permanent magnets indicated that the magnetic quality was affected by the as-cast macrostructure. Improved performance was observed in magnets containing a high percentage of columnar grains whose long axes were parallel to the magnetic axis of the casting. McCaig10 studied the effect of such columnar grain structures upon the magnetostriction characteristics of similar alloys, however no data was presented showing the effects on other magnetic properties. The following paragraphs describe two experiments which were conducted to determine the effect of various grain orientations upon the energy product. Special composite molds were prepared of highly conductive and highly refractive components to remove the heat of solidification from the casting in a controlled manner. Representative macrostructures produced by these techniques are shown in Fig. 1, along with the relative volumes of favorably oriented columnar grains. The alloy, Alnico 5, has the highest permanent magnet performance of any commercial magnet material. It has the nominal weight composition of 8 pct Al, 14 pct Ni, 24 pct Co, 3 pct Cu, and 51 pct Fe. A heat of this material was cast into molds producing the type A and B grain structures shown in Fig. 1 and pairs of the resulting magnets were placed in heat-treating boats so as to eliminate any biasing effects of boat position. After a standard heat treatment the type A magnets, with 16 pct of the volume composed of favorably aligned grains, had a maximum energy value of 3,940,000 gauss-oersteds, while the type B magnets with 73 pct aligned grains averaged 5,090,000. This large im-

Jan 1, 1954

By Frank Fahrenwald

INTRODUCTORY A COMPLETE list of the elements as given for 1915 includes 18 that melt above 1,700° C. There does not exist one complete thermal equilibrium diagram for any pair of these 18 elements. Several of these elements have been combined, in relatively small proportions, with metals of lower melting point: e.g., tungsten, molybdenum, and vanadium, in steels, or with nickel and cobalt; but of this refractory group, platinum is the only one that has been extensively studied in this connection. When one considers that, with few exceptions, the industries have made use of alloys to the exclusion of pure .metals, it is reasonable to expect that alloys of this refractory group will invade fields in which the pure metals have found little application. The past neglect of this class of metals has, no doubt, been partly due to the rarity of some of them, for even though alloys of very valuable properties should be developed, their cost, unless in exceptional applications, would be prohibitive. There is also a well-founded reluctance to undertake research involving very high temperatures which, in the case of most of these elements, must be accompanied by an inert atmosphere as well. This combination of high temperatures* and control of atmosphere within the heating chamber of any furnace of present design is a difficult problem. It is the purpose of this paper to give results,1 of an investigation of one binary series of this group, in which methods were employed that avoided the usual difficulties accompanying high-temperature alloy investigation.

Jan 6, 1916

By Walter Miller

NOW, after a year's continued impact of war, the task of the petroleum-refining industry stands out clearly and looms up in larger aspect. This time it is not, as it was so largely in the first World War, simply a matter of increased quantity- more and more of the same petroleum products that had substantially been standard for years. In this era the emphasis is largely on newer and improved materials which had been produced, if at all, in comparatively insignificant quantities, and for which manufacturing equipment was not available on a large scale. At the beginning of 1942 four great product needs (besides a number of lesser one-) confronted the industry: 100-octane aviation gasoline, toluene for T.N.T. production, high-quality lubricating oils for aviation and Army equipment service, and petroleum chemicals for synthetic rubber manufacture.

Jan 1, 1943

By J. B. Austin

It is now well established, chiefly through the work of Davenport and Bain,' that the influence of temperature upon the rate of transformation of austenite to ferrite at constant temperature is represented by a curve of the type shown in Fig. 5 on page 295 and the reasons for this general shape have been discussed by them in a qualitative way. Thus, the upper part, or nose, of the curve is the resultant of two factors of which the rate of change with temperature is not the same, and by analogy with other like cases it is almost certain that these factors are: (1) the chemical potential, or driving force, of the transformation, which is zero at the equilibrium temperature and increases rapidly as the temperature falls below this point; and (2) a factor analogous to viscosity, or resistance of the crystal lattice to a change in structure, which also increases as the temperature is lowered. Just below the equilibrium temperature this virtual "viscosity" of the metal is relatively low—that is, the metal offers little resistance to a change in lattice—but the driving force is also small, and the net result is that the reaction proceeds slowly. As the temperature is lowered the magnitude of both factors increases; but at first the driving force increases more rapidly than the resistance and the reaction is observed to proceed more rapidly. At lower temperatures, however, the resistance begins to increase faster than the driving force, and eventually, at the nose of the curve, overbalances it, causing the reaction to proceed more and more slowly thereafter. This concept is somewhat, though not completely, analogous to that employed in certain electrical cases where the precise factors are known and are separately measurable. The current I (in amperes or coulombs per second) flowing through a given wire is proportional to the impressed potential, or driving force E, and is inversely proportional to the resistance R of the wire; that is, I = E/R. Stated in a slightly different way, the time required for one coulomb to pass a given point (1/I) is equal to R/E. If the temperature of the whole circuit is changed, the resultant change in 1/I will depend on the relative rates of change of R and of E,

Jan 1, 1935

By J. B. Austin

It is now well established, chiefly through the work of Davenport and Bain,' that the influence of temperature upon the rate of transformation of austenite to ferrite at constant temperature is represented by a curve of the type shown in Fig. 5 on page 295 and the reasons for this general shape have been discussed by them in a qualitative way. Thus, the upper part, or nose, of the curve is the resultant of two factors of which the rate of change with temperature is not the same, and by analogy with other like cases it is almost certain that these factors are: (1) the chemical potential, or driving force, of the transformation, which is zero at the equilibrium temperature and increases rapidly as the temperature falls below this point; and (2) a factor analogous to viscosity, or resistance of the crystal lattice to a change in structure, which also increases as the temperature is lowered. Just below the equilibrium temperature this virtual "viscosity" of the metal is relatively low—that is, the metal offers little resistance to a change in lattice—but the driving force is also small, and the net result is that the reaction proceeds slowly. As the temperature is lowered the magnitude of both factors increases; but at first the driving force increases more rapidly than the resistance and the reaction is observed to proceed more rapidly. At lower temperatures, however, the resistance begins to increase faster than the driving force, and eventually, at the nose of the curve, overbalances it, causing the reaction to proceed more and more slowly thereafter. This concept is somewhat, though not completely, analogous to that employed in certain electrical cases where the precise factors are known and are separately measurable. The current I (in amperes or coulombs per second) flowing through a given wire is proportional to the impressed potential, or driving force E, and is inversely proportional to the resistance R of the wire; that is, I = E/R. Stated in a slightly different way, the time required for one coulomb to pass a given point (1/I) is equal to R/E. If the temperature of the whole circuit is changed, the resultant change in 1/I will depend on the relative rates of change of R and of E,

Jan 1, 1935

By H. P. Wheeler

WHEN Germany invaded Poland in September, 1939, the only operating helium plant in the United States was that near Amarillo. Texas, supplied with helium-bearing natural gas from the near-by Cliffside gas field. Today the Bureau of Mines has five plants capable of producing more than 25 times the prewar helium output of the Amarillo plant. Two of the plants have received Army-Navy "E" flags for their part in the faraway "Battle of the Atlantic," where heliumfilled Navy blimps chased Adolf Hitler's submarines away from American shores. Meteorologists, watching balloons carried high into the stratosphere by helium, determined weather conditions that influenced the selection of D-day and dates for other military operation. Demand for helium doubled overnight when the Navy decided to expand its lighter-than-air activities; and as the blimp patrol proved effective, the helium demand became ever greater. A tribute to the success of the Bureau of Mines in meeting the demand for helium was paid by the late Secretary of the Navy, Frank Knox, in a letter to the Secretary of the Interior on April 10, 1944. Secretary Knox wrote, in part,

Jan 1, 1945

By Walter C. Holmes

IN the recently published book entitled "Man in a Chemical World," by A. Cressy Morrison, the several pages discussing explosives were included in the chapter on "Serving Industry." Such a classification is entirely correct, as blasting explosives function only as a tool for accomplishing certain useful work, a tool which is completely destroyed in one use. Explosives are so important to industry and to modern society, in fact, that it seems impossible to imagine the existence of civilized nations without access to commercial explosives as ready servants. Two main types of explosives are now in use, the low-velocity or deflagrating type, such as black powder, which is adapted for use in coal mining and other applications where a slow, heaving effect is desired, and high explosives of the dynamite type,

Jan 1, 1938

By D. M. Bondurant

AT the present time, the coal industry is greatly interested in any method or machine that will cut the cost of producing a ton of coal, while at the same time producing a product of quality and grade suitable to the customer. Comparatively new and, as yet, little known, auger mining is proving a profitable method of coal recovery. It may be used for the production of low-cost, high-quality coal with equal success from both the hard-to-mine seams, those with banded impurities and bad roof conditions, and the more easily mined seams as classified according to conventional mining methods. A number of units are now in operation and production information is available that should be of particular interest to coal operators and of general interest to anyone associated with the coal-mining industry. Auger mining refers to coal extraction with large size augers capable of drilling to great depths and having a high capacity. Consideration of the equipment and methods used in drilling an ordinary shot-hole will give a picture of auger mining on a smaller scale. At present, auger mining is used largely for recovery of coal from the highwall after strip mining becomes uneconomical because of the type and the thickness of the overburden which must be moved. Coal augers have many of the advantages of present continuous mining machines, along with many more. The four distinct operations of conventional mining-—cutting, drilling, shooting, and loading— are eliminated and replaced by the combined operation of boring and conveying of the coal. The coal recovery auger is an adaptation of the horizontal rock drill used for drilling shot-holes to shatter and loosen overburden in strip mining operations. During the war the Becker County Sand and Gravel Co. of Summersville, W. Va., experimented with drilling coal with 6 and 9-in. rock augers. The results led to the successive development of the 20, 24, 30 and the 36-in. machines, the latter having appeared in the coal fields within the past six months. Because of the great success of the smaller size

Jan 1, 1952

By H. E. Elliott, R. S. Busk, A. T. Peters

ONE of the problems of the fabricator of metals and alloys is the propensity of some composition ranges toward abnormal grain growth during certain stages of fabrication. In this respect magnesium alloys are no exception among alloys. Fortunately, convenient foundry control methods have been developed by which the abnormal grain growth possible in certain magnesium-alloy castings can be suppressed. An unusual characteristic of magnesium alloys, however, is that castings of some composition ranges are subject to local grain growth during heat-treatment without the necessity of intentional mechanical stressing of the part prior to heat-treatment. This effect occurs only under certain critical casting conditions, and only in certain alloys of greater than about 8.5 per cent aluminum content, such as C alloy (Mg, o per cent Al, 2 per cent Zn, 0.2 per cent Mn) and G alloy (Mg, i0 per cent Al, 0.2 per cent Mn). The first observation of this phenomenon in cast magnesium alloys occasioned much surprise, since it is not observed in other metals. Jeffries and Archer' have stated that "the grain size of cast metals, provided they have not been plastically deformed, cannot be changed by heating below the melting point." The study of the conditions leading to abnormal grain growth in cast magnesium alloys, and of the mechanism of this phenomenon, has led to some very interesting observations. Perhaps the most significant of these was the observation that stresses originating from cooling contraction in magnesium-alloy castings are the only stresses necessary, under certain conditions, to cause local recrystallization and subsequent grain growth in the casting during heat-treatment. of abnormal local grain growth was a definite problem in the production foundry on C alloy sand castings. Illustrated (Fig. r) is a picture of a casting scrapped because of this defect. A mottled effect is produced in coarse-grained areas by suitable etching solutions. The properties of metal in the affected area are much impaired by such grain coarsening. Ultimate tensile strengths of half the normal value have been measured in metal of this nature. In this paper are described the techniques that have been developed by The Dow Chemical Co. for studying, and in large measure solving, this production problem. Also discussed are studies of the mechanism by which excessive grain coarsening occurs, and the fundamental conditions that produce this effect. The abnormal grain growth discussed in this paper will be referred to as "germination," since this term has been defined' as any process leading to an abnormally coarse grain size. This paper deals only with abnormal local grain growth that may occur during the solution heat-treatment of certain magnesium-alloy castings, as dis-

Jan 1, 1945

By AIME AIME

The following acts of the Directors are reported for the information of members:¬ At a meeting held November 3, 1905, Messrs. Henri Le Chatelier, of Paris, France, and Andrew Carnegie, of New York, N. Y., having been nominated by a large number of members, and recommended by unanimous vote of the Council, were unanimously elected Honorary Members, in recognition of their distinguished services to the arts and professions represented by the Institute. At a meeting held February 7, 1,906, Dr. James Douglas, of New York, N. Y., having been" nominated by a large number of leading members, and recommended by unammous vote of the Council, was unanimously elected an Honorary Member, in recognition of his distinguished services to the practice and the literature of mining and metallurgy, his zealous and loyal devotion to this Institute, his fraternal generosity towards professional colleagues, and his effective advocacy, by public utterance and private example, of the free communication of technical knowledge and experience. At the same meeting, By-Law IV., which now authorizes the Secretary to appoint an '1 Assistant Editor," was amended by substituting the words, " Assistant with the title of Editor." At the same meeting, the resignation of Mr. Theodore Dwight, as Assistant Secretary and Assistant Treasurer of the Institute, was presented and accepted, and the Secretary was instructed to express to Mr. Dwight the thanks of the Board for his loyal and efficient services, and its regret that he could not continue in that position. . [SECRETARY'S NOTE.-Mr. Dwight's resignation, dictated solely by the demands of private business, covers only his immediate management of this office. He is still a Director and Councilor, and a representative of the Institute in matters connected with the new Carnegie Building, etc.-R. W. R.] At the same meeting, the Secretary and the Treasurer reported respectively their appointment of Mr. Henry WT. B. Howard as Assistant Secretary and Assistant Treasurer, to fill

Mar 1, 1906

By M. R. HULL

FOLLOWING the discovery of a body of ore that appears to have commercial possibilities there is a period of development work to determine its extent and grade and the most economical method of mining it. Laboratory tests are made in an effort to determine the most practicable and economical treatment for the extraction of the valuable constituents of the ore and these tests are carried farther and checked in a pilot or test mill. The rate at which the ore is to be mined and the daily capacity of the plants that are to treat it will depend on a number of important factors such as: The size of the orebody; the capital available for building the plants; the market or demand for the final product; the supply of skilled and common labor available for the construction, operation and maintenance of the plants; the quantity and quality of available water, and the amount and cost of power that can be purchased or that can be economically developed. Having decided on the treatment that is to be given to the ore and after full consideration of the above factors the management decides to erect a reduction plant of a given capacity.

Jan 1, 1926

By N. K. Chen, R. Maddin

THE textures of straight-rolled and of cross-rolled molybdenum were first determined with the aid of pole figures by Custers and Riemersma.' These authors have shown that for straight-rolling, the main texture was (100) [0111 with a considerable spread about the rolling direction. After cross-rolling a second texture was obtained in which there was a [111] axis perpendicular to the rolling plane, possessing a rotary symmetry. Recently Semchy-shen and Timmons2 in their study of preferred orientation of arc-cast molybdenum sheet obtained similar pole figures. In these two investigations, polycrystalline materials were used. In the main, the textures of molybdenum in these cases are qualitatively consistent with rolling textures of other body-centered cubic metals, such as iron and Fe-Si alloys." In the present investigation, single crystals of molybdenum were deformed by rolling with respect to specific crystallographic planes and directions. Since the deformation textures of polycrystalline aggregates have been related intimately to the behavior of individual grains,4 a study of possible correlations of final textures with respect to the initial orientations of the single crystals might conceivably lead to a better understanding of the textures. Annealing treatments were carried out after deformation in order to study the recrystallization characteristics as well as the recrystallization texture. Rolling of Single Crystals Single crystals of molybdenum (about 1/8 in. in diarn x 1-in. long), grown by the method previously described,5 were cold-rolled without intermediate anneals. Except for specimens MR-1 and MR-2, which were rolled at random in the preliminary test in order to find a proper rate of reduction, all other specimens were carefully documented as to their respective orientation before deformation by means of X-ray Laue back-reflection methods. A stereo-graphic projection was constructed from which it was possible to determine a particular plane and direction to be considered for rolling. Parallel flat surfaces were then polished metallographically with respect to a reference scratch on the specimen which was mounted in sealing wax. These flat surfaces contained the plane chosen for rolling. After etching, a Laue back-reflection photogram was again made of one of the flat surfaces to determine the exact plane of rolling. The initial orientations of all the specimens (specified by two elements for each crystal, direction of rolling and the pole of the rolling plane) are summarized in Fig. 1. The specimens were mounted in plasticene between two hardened Si-Fe plates. The sandwich was then rolled down, keeping the direction constant in the case of straight-rolling. In cross-rolling (MR-10, MR-11, and MR-12) the sandwich was rotated 90" after each pass so that every first and third pass contained the same rolling direction. Specimens MR-14, MR-15, and MR-16 were compression-rolled following the manner of Barrett." In these cases the direction of the sandwich through the rolls was changed by 3" to 5" for each pass until the specimens were rolled to the desired reduction in thickness. It was found that if extreme care was exercised in rolling, i. e., the amount of deformation per pass was extremely small, the specimens could be rolled to a large reduction in thickness. The rate of reduction used, with a single exception of MR-1. was generally 0.001 in. per 10 passes. Thus, it took about 800 passes to reduce a specimen to a final reduction in thickness of 87 to 98 pct. The results of rolling are shown in Table I. Cold-Rolling Textures The final orientations were determined by the conventional Laue transmission method," using molybdenum radiation, with or without a zirconium filter. Pole figures were plotted from (1101 and (200) reflections in which three degrees of intensity— heavy, medium, and light—were determined visually. Three main types of textures have been observed from the deformed single crystals. These are: 1—a

Jan 1, 1954

By C. O. Brawner

INTRODUCTION Tailings dams up to about 200 ft. high are proposed to store tailings for a major mining operation on Marinduque Island in the Philippines. The original design of the dam utilized a compacted laterite starter dam followed by hydraulic placement of cycloned sands to form slime retaining dykes along the outer face of the dam. The upstream method of construction was proposed. In view of the failure of numerous tailings dams in Chile during the EL Cobre earthquake (I), an investigation was performed to assess the earthquake stability of the proposed dam. This included a soil investigation on the first cycloned sand dyke, which had been built to a height of 45 ft. Results indicated that the density of the sand was much lower than existing empirical criteria consider to be necessary for resistance to liquefaction. As a result, the dam was redesigned. The downstream method of construction was selected and a yearly construction program was developed to make use of sand available by cycloning. To increase shear strength, improve resistance to liquefaction, and to utilize steeper slopes, compaction of all sand in the dam was specified. A special underdrainage layer and toe drains were incorporated in the design. Details of the decant system and surface erosion alternatives are described. SITE CONDITIONS The mining project is located in the Philippine Islands. At the present annual rate of production, about 4,230,000 cu.m. of tailings will be produced yearly. The volume requirements for tailings storage design for the first 10 years of operation are in the order of 45,000,000 cu.m. The topography near the mine is mountainous with many gullies and canyons carved out by high intensity rainfall and runoff. The bedrock, which is generally shallow and weathered for a considerable depth, is overlain by laterite soils. Vegetation is comprised largely of palms, banana trees, and tropical shrubs and grasses. Precipitation is heavy. The average yearly rainfall over 24 years is 65.2 in. and the maximum recorded 24 hour rainfall is 9.0 in. High intensity rainfall is associated with typhoon storms, which are a seasonal threat inthe Philippines. Fig. 1 shows a summary of monthly precipitation.

Jan 1, 1972

By O. G. Paasche, Yuan-Shou Shen

THERE is a disagreement among the various authors about the exact manner of transformation of ZrCr2. Rostokerl and others2 stated that ZrCr2 had a C-14 (MgZn2) type of structure below 1000°C and a C-15 (MgCu2) type of structure at temperatures above 1000°C. Alisova3 and others4 reached the opposite conclusion and stated that the transformation temperature is close to the melting point of ZrCr2. A literature survey shows that various investigators3'= who homogenized the specimens at a temperature higher than 1000°C have concluded that ZrCr2 had the C-15 structure at room temperature. Meanwhile, Jordan et al.4 reached similar conclusions without annealing the specimen. Other investigators1,2,6,7 who X-rayed the specimens in the as-cast condition without annealing reached different conclusions. The investigation reported herein was conducted with the aim of exploring the exact manner of transformation of ZrCr2 by various heat treatment tests. The alloys for this examination were prepared from iodide-reduced zirconium crystal bars, 99.9 pct purity, and electrolytic chromium, 99.9 pct purity. They were melted in a nonconsumable electrode arc furnace with water-cooled copper crucible in a helium atmosphere. The melting loss of each alloy was less than 1.5 pct by weight. Chemical analysis of a randomly selected specimen indicated that there was a very close agreement between calculated and analyzed compositions. Before being heat-treated each specimen was encapsulated in a vycor or quartz tube inside which an argon atmosphere was maintained at a pressure of lower than 1 atm. In determining the crystal structure of each specimen with a Debye-Scherrer camera, the standard procedure8 for X-ray quality analysis (Hanawalt method) was followed. The different series of heat treatment tests in this investigation are tabulated in Tables I and 11. The tests in Series I, specimens from 1-1 to 1-9, which were similar to Rostoker's experiment1 indicated that the transformation temperature seemed to fall between 870° and 900°C and that the crystal structure of ZrCr2 at lower temperature seemed to be of the C-14 type. However, once the compound is transformed to C-15 type, it is impossible to reverse the transformation back to the C-14 type by first heating the specimen above 900°C and then annealing it slowly below 900°C as shown in Experiments II-1 to II-3. Thus, it appears that the specimen of ZrCr2 will transform from C-14 to C-15 structure when heated above 900°C but will not transform from C-15 to C-14 when annealed slowly passing 900° C even after the extremely slow cooling process such as indicated in the experiment of Specimen II-3. As a valid transformation temperature is a temperature at which the transformation is reversible, therefore the temperature 900°C (or other temperature close to 900°C) is not the transformation temperature for ZrCr2 and the C-14 structure is not the stable structure of ZrCr2 at lower temperatures. The C-14 structure is retained at room temperature because the transformation to C-15 structure is very sluggish and the fast cooling after melting does not allow enough time for the transformation to take place. Additional energy is required to alter the metastable condition of the C-14 structure. The sluggishness of this transformation was again demonstrated through another series of experiments. Four specimens with C-14 structure were taken. Then they were annealed at 900°C but each specimen was soaked for a different period of time, Table 11. X-ray diffraction patterns of this group indicated that the C-14 structure gradually disappeared as the soaking period was lengthened. The figures listed under the column "C-14 Structure, pct" were estimated from the intensity of the d = 2.330 line of the diffraction pattern corresponding to the structure. Notice that the intensity of this line became weaker for longer soaking periods. To determine the transformation temperature of ZrCr2, specimens with C-14 structure (as-cast condition) were annealed at 1300°, 1400°, 1500°, 1550°, and 1600°C, respectively. A final specimen was first heat-treated to 1500°C in order to transform it to C-15 structure, then heat-treated at 1600°C again. From the X-ray analyses of this series of tests, Specimen Nos. III-1 to III-6, it is evident that a transition from C-15 structure at lower temperatures to the C-14 structure occurs at some temperature between 1550° and 1600°C.

Jan 1, 1969

By John C. Cosgrove

IT was just five minutes past midnight, on Wednesday, Jan. 5, 1938, that Mrs. Cosgrove and I sailed from New York City. Our trip was to completely circle the globe, to cover over 40,000 miles and stop at thirty ports-from New York to Trinidad, to South America, via South Africa to the Orient, to India, to the Malay States, to Indo-China, the Philippines, Australia, New Zealand, Fiji, and across the Pacific home via Honolulu. It is not my intention to make this a complete, technical study of coal or coal mining in the various countries that .we visited but more to outline the general in- formation that the mining engineer and coal operator would absorb in his travels. Coal is the universal fuel and is in use wherever there is commerce and industry. Even on our ship, which, like practically all ocean liners was an oil-burner, a considerable quantity of coal was used for cooking.

Jan 1, 1939