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By Wayne E. Glenn

A centennial meeting should be a time to take stock, to evaluate performance, to plan ahead. It is like a line in a televised commercial that goes, "You've come a long way to get where you've got to today." And no less should be said of the mining and energy industries. We have come a long way. A hundred years ago when AIME was founded, this country produced 23 million tons of bituminous coal and 5.2 million bbl of oil. The figures in 1970 were about 580 million tons of coal and 4.1 billion bbl of oil. In spite of such accomplishments, serious and compelling voices are heard in the land - doubting sincerity, questioning corporate structures, and challenging ethics. Those doubts are raised in one part of Washington at the same time that other sections of the Capitol are asking us to produce more energy in order to keep up with population growth, emerging nations, and new technologies. Those of us in the fuel or energy business frequently talk about the race for energy. The question is, can we develop enough energy fast enough to outdistance our present and increasing demands? Recently I heard of an incident that - in an odd way - caused me to think of the energy race. The incident involved a sky-diver who jumped from an airplane without a parachute. He was handed a chute in mid-air by a sky-diving companion. He put it on, opened it, and landed safely. In a way, it seems to me that our society is hurtling through space and that it needs some help from the energy industries to land safely. We're doing our best, but under some rather difficult conditions. Because of illegal strikes and work stoppages the coal parachute is snarled a bit. The cut in percentage depletion and other tax changes have put some holes in the oil parachute. And the gas ´'chute has been in trouble for some time because of unrealistic controls on producer prices. The irony of the situation is that some of the very people who have been taking potshots at the energy parachutes for a long time are the ones who are complaining loudest now because the 'chutes are not functioning the way they could. The safety of the entire nation can depend on the energy industries.

Jan 1, 1971

By J. E. Johnson

THE production of metal-working tools has been revolutionized within the last 18 years, since the invention by Taylor and White of a process of heat-treating steel tools, which resulted in increasing their cutting capacity several fold over what it had been before. This was an exceedingly important invention, although it consisted principally, in establishing this fact overheating when it accidentally, occurred in the ordinary:-process of forging, spoiled the steel, but if carried very much farther or to-a point that would have been considered absolutely ruinous to the steel under the old ideas, it resulted in imparting a cutting power several times as: high as had ever been obtainable before. The quality that gives the steel this power eventually received the name of "red hardness." This name originated in the fact that tools possessing this property retain their resistance to deformation even when subjected to, such severe cutting stresses that the metal just back of the point is heated, under certain conditions, to a visible red. It is interesting in this connection to note that the edge of the tool itself does not become red because it is continually cooled by the fresh metal into which it is forced. The result of Taylor and White's invention was an intensive study, of tool steels all over the world and, although there was-great diversity of analysis in the high-speed steels of the early days, these steels today generally have an approximately similar composition, the principal constituents being froth 15 to 20 per cent. of tungsten, from 4 to 6 percent. of chromium, from 1 to 2 per cent. of vanadium, and from 0.50 to 1 per cent. of carbon. It is probably safe to say that standard brands of such high-speed steels will do from five to ten times as much work in a given time as the carbon steels, and even the Musket steels, which were the sole dependence up to the beginning of this century, when the Taylor-White process was discovered. With the increasing cost of labor, it is not surprising that these steels have driven froth the market, for all but limited purposes, the older types of steel.

Jan 2, 1919

D. EPPELSHEIMER, * Middletown, Ohio.-The housing of employees has so many and so varied aspects that in order to reach even an approximately correct solution it is necessary to have in mind a few fundamental principles; but it is not possible as yet to write these housing principles in the clear and correct form that is possible with many of our natural laws. Manifestly, the problem depends first on the kind of people it is necessary to house. What is suitable for the Southern unattached negro is not suitable for the married skilled American. The influx of colored labor has affected quite a number of what were satisfactorily housed communities. The second important factor is the relative proportion of the number of employees to the total employable population of the community in which the industry is located. The employer of a hundred men in. a large city has little responsibility in the matter of housing his employees. If he employs 75 per cent. of the employable population in a community of 27,000, as is the case of the company with which the writer is connected, it means a large responsibility. In the establishment of an entirely new plant in a more or less isolated place, the responsibility becomes greater. As engineers, we design and write the specifications for the machinery to accomplish a definite purpose, and proceed to house it, provide the necessary buildings with their accessories in the way of cranes, or heating systems, or sprinkling systems, as the case may be. There is no reason why the operating force should not be built up in very much the same way: design the organization, write its specifications so that the employment department can secure the proper men, and then house that organization with just as much thought and care as is given the plant. In the plant, the various machines will work along certain definite lines and accomplish certain results; but even if we start with the proper organization it takes considerable time to get that organization working together. One of the most important elements to this end is the proper housing of the organization. A man usually spends more time at home than at work. Proper surroundings and a comfortable, convenient house of good appearance exercise an influence that cannot be denied, and an employee situated in such surroundings is far more inclined to follow the policies of his employer and take an active part in furthering them

Jan 5, 1919

By D. M. Dunbar

LONG before Columbus discovered America the original inhabitants toiled in the copper workings of the Andean Cordillera. Their best diggings appear to have been at Chuquicamata, site of the huge present-day open pit owned by the Chile Exploration Co., subsidiary of Anaconda Copper Mining Co. Located in Antofagasta Province of northern Chile, Chuquicamata is in the Atacama desert, high on the western slope of the Andes at 9500-ft elevation. In the Chuquicamata area the Atacama desert merges into the Cordillera. The climate is extremely arid and precipitation, either in the form of rain or snow, is very infrequent. The temperature varies from 50° to 85°F during the day, and drops to 20° to 40° at night. The Antofagasta and Bolivia Railroad, which connects the Chilean Port of Antofagasta with La Paz, Bolivia, passes within approximately 6 miles of the plant. A branch from the main line to Chuquicamata serves the property for outgoing copper and incoming freight. The distance to Antofagasta by rail is 163 miles. Previous to the Inca conquest, this region was inhabited by the Chuco Indians, a small tribe, descendants of the Aymaras and Quechuas. The Incas, whose capital was located in Cuzco, Peru, gradually extended their empire to the south, reaching at one time to what is now central Chile. It is believed that they built crude primitive furnaces on the banks of the Rio Salado where on a small scale they smelted copper ore from Chuquicamata. At the time of the subsequent Spanish conquest, legend has it that Diego de Almagro, on his return to Cuzco in 1536 after his invasion of Chile, obtained from these furnaces metallic copper for horseshoes. During the period from 1560 to 1879 the high grade veins of the Chuquicamata deposit were worked superficially by the Spaniards and Bolivians. The treaty signed after the war of 1879 recognized the sovereignty of Chile over this territory and Chile, realizing the importance of the district, started to develop it in an orderly manner, although only high grade veins were worked. New Process Is Key Reports on the deposit were brought to the attention of Albert C. Burrage, a Boston lawyer and financier, in 1910. Chuquicamata was described as a huge deposit of ore that was not amenable to the usual treatment by concentrating and smelting since much of the copper occurred as oxides. He had been working on a process for the recovery of copper from sulphide ore which involved a sulphating roast, leaching of the roasted product, and pre-

Jan 1, 1952

By W. B. Weeks, H. K. Shearer

The year 1937 brought to south Arkansas increased drilling activity and production. Oil production amounted to 12,159,440 bbl., an increase of 1,504,500 bbl., or 14.1 per cent over 1936. This was the largest production since 1931, and the first annual increase since 1925, when the deeper sands at Smackover were developed. There were 177 wells completed during the year, with 103 oil wells, 6 gas wells, and 68 dry holes, an increase of more than 100 per cent over 1936. Of the 56 wildcat wells drilled, 52 were dry and 4 produced oil. Two new fields, one important extension and three minor extensions were discovered. The trend toward deeper drilling is shown by the fact that 97 wells were more than 5000 ft. deep, including 80 over 6000 ft. and 13 over 7000 ft., although the depth record of 7973 ft., made in 1935, was not exceeded. Geological Section Deeper and more extensive drilling during the past few years, not only in south Arkansas but also in adjacent parts of north Louisiana and east Texas, has furnished much important geological information and has brought out some very unexpected facts in regard to structural and depositional conditions in the series of formations laid down in the interval between the end of the Pennsylvanian and early Cretaceous time. It is now evident that an important basin of salt deposition existed in the Arkansas-Louisiana-Texas area, but it is still an open question whether this salt basin was contemporaneous and continuous with the even larger Gulf Coast salt basin extending from Mississippi to Mexico. The accompanying columnar section (Fig. 1) shows the producing zones and names that have been applied to the several subsurface formations, most of which have no outcrop equivalents. This is for the convenience of readers unfamiliar with recent developments, but the correlations and nomenclature cannot yet be considered final. These formations will be discussed in more detail in various papers to be published in the near future.

Jan 1, 1938

By Elmer W. Pehrson

The term "survival" in the title means the preservation of a society in which men are free from the political and economic restraints that characterize totalitarian systems, be they communist, socialist or facist. It means the ability to withstand the enemy's offensives in the fields of propaganda, commercial competition and, if necessary, war. The temptation to substitute "victory" for "survival" is great but a realistic appraisal of the creeping socialism and demagoguery that pervade our time indicates that we may have to be content with survival in status quo. "Mineral strength" means assurance that adequate supplies will be available to meet all the contingencies of cold and hot wars. The overall mineral position of the U. S. viewed in the light of these premises is far from secure. It is true that we are the leading producing and consuming nation of the world, but the Soviet Union is gaining and the Sino-Soviet Bloc confronts us with a sobering potential. The emergence of the Common Market in Europe as an economic and political unit places a third independent entity into the competition. Our total mineral output continues on an up- ward trend but the reverse is true in certain strategic commodities. Moreover, consumption is moving ahead faster than production so that there is increasing dependence on imports which has significant adverse geopolitical connotations. There is widespread belief that our resources can at least maintain present levels of self-sufficiency during this critical period in world history, but social dreamers, the labor monopoly, and trade and taxation policies have discouraged aggressive activity in exploration and development, and access to essential foreign sources is threatened by a variety of circumstances. Our stockpiles, belatedly built up to achieve minimum protection against shortages in time of war, are under. political attack and threatened with partial destruction on the basis of what are at best uncertain assumptions regarding the new: look of global warfare.

Jan 11, 1962

By William P. Blake

In addition to uintaite, the Uintah Mountains contain a deposit, or vein, of the peculiar hydrocarbon mineral, to which I have given the name wurtzilite, * in honor of the chemist, Henry Wurtz, Ph.D., of New York, who, in 1865, described grahamite, and who has added to our knowledge of the composition of the hydrocarbon minerals. Wurtzilite and uintaite are very similar in appearance, but are very different in their physical and chemical properties. Both are black, splendent and shining in fresh fracture; but the wurtzilite has a decided toughness, and a degree of elasticity, especially when warmed, which suggests to some persons a resemblance to caoutchouc. It was at first, at Salt Lake, believed and reported to be a mineral form of India-rubber, and great expectations of its value as a substitute for crude rubber were indulged in. It was, however, found that it would not act like rubber with sulphur; it would not incorporate with it and become "volcanized," and it was very refractory and insoluble in the ordinary solvents of rubber and of uintaite. The elasticity, though unlike the elasticity of rubber, led to the reference of the mineral to the species elaterite, the only name under which an elastic bitumen is described in the mineralogies; and it is so called in the list of the mineral products of Utah, given in the last message of the Governor of the Territory. The name elaterite, as used by Dana, covers at least three differing substances, ranging in specific gravity from 0.905 to 1.223. Two of the varieties are soft and elastic, much like India-rubber, and one is occasionally hard and brittle, imbedded in the softer kinds. All are rare, and comparatively unknown, and not generally represented in mineral collections. One of the varieties referred to here is the subterranean fungus from Derbyshire, described by Lister as early as 1673.

Jan 1, 1890

By Alan Morris

THE investigation of the hot-working properties of metals and alloys furnishes a problem which has been attacked in many ways. Tensile, impact and hardness tests on heated specimens have furnished interesting data, but in most cases either the tests are difficult to make or the results hard to translate into terms of practical value. Some investigators have used the drop hammer to advantage. It furnishes a rapid and simple method of comparing the plasticity of metals at elevated temperatures. The indications obtained by its use are of value only in so far as their significance is understood and they can be intelligently used to predict the behavior of a given metal under given hot-working conditions. The work reported here was undertaken not only to add-something to the existing volume of such data but also to contribute to our understanding of the results. Doerinckel and Trockels1 used cylindrical specimens and determined the work required to reduce the specimen to one-half the original height. Ellis2 studied the effect of constitution on the malleability of steel at high temperature. His method and that of Kent3 were similar to the one used in the present work. The tests described by Kent were made on samples of tin, zinc, aluminum, copper, lead, 70:30 and 60:40 brasses, with and without a small quantity of lead. He concluded that the test would "indicate whether a material can be forged at a given temperature without cracking." This interpretation must be used with caution. While it is probably true within limits, one must consider the severity of the forging operation. Again, it will not apply strictly to forms of hot working other than forging. For instance, an alloy running 61.0 per cent. copper, 3.25 per cent. lead, remainder zinc, will crack badly in the test, yet it is extruded commercially. When the possibility of hot-working a new alloy is being considered a study of its drop-hammer test should help

Jan 1, 1931

By R. J. Linney

Reserve Mining Co. produces 5 million tons of iron ore pellets per year. The finished product runs about 65.50 pct Fe, with 7.75 to 8.00 pct SiO2. Less than 12 pct arrives at the blast furnaces smaller than % in. This plant was originally designed to produce 3.75 tons annually—not 5 million. To handle the increased tonnage a fifth fine crushing line was added, and some very minor changes were made. When production can be stepped up 33 1/3 pct without extensive additions or changes—within the short period of a year—basic engineering has been sound. Operators of the plant consider it the best design job they have seen or heard of, and competent authorities have said that start-up was quicker and easier than for any previous large-scale minerals beneficiation plant. One big advantage is the elbow room allowed. Generally speaking, there is an eternal conflict between operator and designer over space. The designer has his costs per cubic foot, and he is keenly aware that if he permits the number of cubic feet to rise unnecessarily, total costs will be too high. But this was a new operation, and on a large scale. There were no proven standards to go by. Realizing this, Reserve's engineers provided ample and efficient access to machinery, allowing extra space for unanticipated situations. In three years of production this planning has paid off handsomely. Gravity Flow Saves Time and Money: This plant is on a rocky hillside, the car dumper about 270 ft above Lake Superior. In locating buildings and placing machinery the designers mad= good use of gravity flow, at considerable financial savings. In the concentrator building from rod mills to filters, gravity carries the material between all stages of the operation except one—the closed circuit pumping of concentrate between cone classifiers and ball mills. Since no machine is located directly above any other, an observer can stand on the truck ramp adjacent to the offices and laboratory and see practically every phase of activity in the huge building. The first mill section started in August 1955. After a day's run several modifications were made on auxiliary chutes and launders where spillage had occurred. This procedure was followed for the first

Jan 1, 1960

By Y. A. Chang

Phase relationships in the system Cr-Si have been established based on the melting point, X-ray, metallo-graphic, and DTA studies. The three intermediate phases, Cr3Si, Cr5Si,, and CrSi,, melt congruently at 177V ± I@,Cr3Si, 1680"i 20°, and 1490" *20°C, respectively, while the fourth intermediate phase CrSi, melts peritectically at 1413" i 5°C to Cr5Si3 and a melt containing 51 at. pct Si. The temperatures and compositions of the four eutectic isotherms occurring in this system are given below: DTA and metallographic evidences indicate that Cr5Si, undergoes a phase transformation at 1505" i20°C. The high-temperature form of this phase could not be retained by the quenching techniques used in this study. TECHNOLOGICAL interest in the developing of composite systems, consisting of Sic on the one hand as a fiber-reinforced material and metallic substances such as chromium, nickel, or Cr-Ni alloys as a binding agent on the other hand, stimulated the present investigation of phase relationships in the binary system Cr-Si. Earlier works concerning this system have been evaluated and summarized by ansen and Anderko.' Their phase diagram was based mainly on the works of Kieffer, Benesovsky, and schroth2 and Kurnakov.~ According to these authors, the three intermediate phases Cr3Si, CrSi, and CrSi, all melt congruently at approximately 1730°, 1600°, and 1550°C. However, they did not agree on the compositional stability of the fourth intermediate phase between Cr3Si and CrSi. Later Parthe, Nowotny, and schmid4 determined the structure of this phase to be tetragonal T-1 type using the single-crystal method, and concluded that this phase had a formula of Cr5Si3. Since the compilation of Hansen and Anderko,' a new phase diagram for the system Cr-Si has been proposed by Elliott5 based on the works of Goldschmidt and rand,' Guseva and ~vechkin,~ and Trusova, Kuzev, and Ormont8 and the earlier works quoted by Hansen and Anderko.' According to this proposed phase diagram, all four intermediate phases have large ranges of homogeneity and all melt congruently. More recently, Svechnikov, Kocherzhinskii, and yupkog studied the system Cr-Si by the DTA-method. According to their findings, the three intermediate phases, Cr3Si, Cr5Si3, and CrSi,, melt congruently at 1700°, 1720°, and 1475"C, respectively, while the fourth intermediate phase, CrSi, melts peritectically at 1475°C to Cr5Si3 and a melt containing 50 at. pct Si. The temperatures and compositions of the four eutectic isotherms were found to be: In view of the discrepancies existing in the literature concerning the system Cr-Si, it was decided to rein-vestigate the phase relationships in this system. EXPERIMENTAL a) Starting Materials. Chromium disilicide and chromium or silicon powders were used in the present study to prepare the melting point and DTA samples. CrSi, was obtained by directly reacting cold-pressed elemental powders in an atmosphere of Hz at a temperature of about 1250°C. Chromium powder, purchased from Stark Chemical Co., had the following impurities in ppm: Fe, 200; Mg, 1000; and 0, 250; while silicon powder, purchased from the Welded Carbide Co., had the following impurities in ppm: Ca, 700; and Fe, 3500. b) Melting-Point Determination and Differential Thermal Analysis. Cylindrical melting-point samples of approximately 13 mm in diam and 30 mm in length with a rectangular groove in the center were prepared by hot-pressing of well-mixed powder mixtures in graphite dies. Before the melting-point determination, the hot-pressed samples were ground on a sand paper to remove any minute surface contamination of graphite. A small hole of 1 mm in diam, drilled on the center portion of the samples, served as a blackbody cavity for the temperature measurements. DTA samples approximately 13 mm in diam and 15 mm in length were prepared in a manner similar to the melting-point samples. Melting points were determined using the Pirani technique under a helium atmosphere of 40 psi. The design, performance, and operation of this apparatus have been described in detail by Rudy and ~ro~ulski.'~ The temperature measurements were carried out with a calibrated disappearing-filament-type micro-pyrometer. The measured temperature was corrected for losses from the quartz window of the melting-point furnace and for deviations from blackbody conditions of the observation hole. The procedure for temperature correction has also been previously described." The DTA method of Heetderks, Rudy and Eckertl' was also used to check any phase transformations of selected alloys in the system Cr-Si. It was not possible to make remated runs on the same sample once melt-

Jan 1, 1969

By Russell G. Wayland

THIS paper gives the author's personal idea of the general viewpoint of the world's largest mica consumer, the U. S. Army, toward the supply, uses, and conservation of mica. However, to cover so broad a subject in a brief paper will require the dismissal of many phases with little or no mention. For example, it will be necessary to omit further reference to phlogopite or amber mica, even though amber block and splittings for certain spark plugs and commutator segments present some supply problems. This paper will deal entirely with muscovite, or white mica. MUSCOVITE MICA Muscovite mica is available commercially in four general forms; namely, as block mica, as splittings, as washer punch, and as scrap mica.1 No strategic importance is attached to washer punch and scrap mica, even though scrap has found some use in military construction and in electrical ceramics. The use of washer punch as such has fallen off with the non-manufacture of household electrical appliances. Some qualities of block mica are also of little or no interest, but other qualities of block mica and all splittings are considered of vital importance. Army equipment requires large amounts of muscovite mica splittings in the form of built-up mica commutator segments and coil insulation in motors and generators. Other military items using significant amounts of muscovite splittings are transformers, switchboards, and blasting apparatus. Flexible mica tape, made from bookform or loose-dusted splittings cemented to paper, linen, glass cloth, and other backing, is widely used in coil insulation in heavy electrical equipment and in aircraft generators. All muscovite mica splittings come from India, principally because of the enormous amount of hand labor required in their preparation. In this emergency, the need for them was anticipated and large industry and government stocks were on hand, while shipments have continued to come by sea in spite of wartime hazards. With the possible exception of certain bookform splittings, no trouble is anticipated in supply. Accordingly, the remainder of this paper is devoted to block (or sheet) muscovite mica, including condenser film that is split from block. THE MICA PROBLEM Block muscovite mica is commercially classified into the following general qualities, beginning with the best quality: I. Clear and Slightly Stained (C & SS). 2. Fair Stained (FS). 3. Good Stained (GS). 4. Stained (S). 5. Heavy Stained (HS). 6. Black Spotted. The ratio of relative commercial abundance in the present new supply of these micas is approximately I C & SS to 4 FS to 10 GS to 14 S to whatever the

Jan 1, 1944

By Lucien Eaton

THE accuracy with which detachable bits can be sharpened and gauged by grinding has made possible refinements in design that cannot be attained by forging. This applies particularly to gauging, where accuracy is of the greatest importance. Gauge changes of 1/32 in., and even 1/16 in., are now feasible, whereas 1/16 -in. changes are about the limit in accuracy for forged bits. These small changes in gauge are feasible, however, only with certain fundamental principles of design. Within reasonable limits the depth to which a hole can be drilled is dependent primarily upon the loss in gauge, or diameter, of the bit. In drilling there is always a certain amount of " overdrilling "-the bouncing of the bit in the hole and its rotation wear away the walls-so that the actual diameter of the hole is greater than the diameter of the bit. The amount of this overdrilling depends upon the kind of rock being drilled, and is sometimes sufficient to permit the use of the same diameter of bit for the full depth of the hole. If, for instance, a 1 ¾ -in. diameter bit overdrills 1/32 in. in diameter, and loses 1/64 in. in gauge in drilling 2 ft. of hole, the bottom of the hole is still 1/64 in. larger than the original diameter of the bit, and a new 1 3/4-in. bit can be used to drill the next 2 ft. If, however, the overdrill is less than the loss in gauge, the next bit must be of smaller diameter. The first requisite in reducing loss of gauge in drilling is to have the points and corners of the wings of the bit cut circles of the same diameter, thus producing a reaming surface with continuous bearing on the wall of the hole. The greater the reaming surface, the less the gauge loss that is to be expected. If the reaming surface, however, is too large, it may impede the rotation of the bit through excessive friction. This principle was probably first recognized in the design of the Carr bit (Fig. 1)) a bit with a single cutting edge of wide angle, a definite reaming edge, and a large center hole. The same idea was followed in designing the double-taper cross bits, which are now standard almost everywhere Fig. 2 illustrates a typical double-taper cross bit. The taper from the point of the wing A to a little behind the corner B is 5° and from

Jan 1, 1939

By Geo. H. Ashley

The following paper is intended to be suggestive only, and to open the way for discussion and further observation. Its preparation was requested only two days before the time limit set for the submission of the papers comprising this symposium. Thus no time existed for detailed studies, so it is largely a memorandum of such facts as have come incidentally to the notice of the writer in the study of coal in the field. The field study of sulfur in coal has received very little special attention or description from coal student's. The presence of sulfur concretions is noted in hundreds of descriptions, and certain benches of a coal bed may be described as "sulfury" or the presence and position of sulfur bands may be noted in coal sections in connection with sampling. It may be accepted that some sulfur is present in all coal. The amount varies greatly in different regions, in different beds, and in the same bed in different areas. The anthracite of Rhode Island comes the nearest of any coal known to the writer of being free from sulfur, several analyses of that coal showing less than 0.1 per cent. Subbitumi-nous coals in Colorado in a few places have close to 0.2 per cent. of sulfur on the dry-coal basis and in other states subbituminous coals approach this lower limit. Bituminous coals seldom run under 0.4 per cent. of sulfur on the dry basis, though in a few places dry bituminous coals in Colorado and Washington have between 0.3 and 0.4 per cent. The better known bituminous coals have almost everywhere over 0.4 per cent. The best of the Pocahontas and New River coals run close to 0.4 per cent., but there is very little commercial coal in Pennsylvania, Ohio, Indiana, Illinois, Kentucky, or the other states, that runs under 0.5 per cent. on the dry basis. From these minimum figures, the amount will range up to 5 or 6 per cent. or higher if visible sulfur is not excluded. It must be remembered that the usual analysis of a coal bed is not intended to give the total proportion of sulfur in the bed but the amount in the coal after the removal of the more obvious and larger sulfur masses. Professor Parr has already pointed out that, chemically, sulfur occurs in several forms: as pyrite, organic sulfur, sulfates, and possibly as un-combined sulfur. Sulfur in the form of sulfates is commonly the obvious result of the weathering of pyrite and may be found in the coal within .

Jan 1, 1920

By James C. Bayles

The ideal pressure-tube is obviously the one which combines the greatest strength with the least weight of material consistent with the uses for which it is designed or employed. The inside of the pipe is the first concern of the engineer. It should be cylindrical, smooth, and of the requisite capacity for the purpose in view. It should be in lengths as great as can be oonveniently handled, so that the couplings may be as few as possible. With the walls of the tube the engineer has no further occasion to concern himself than to make sure they are adequate to carry the internal and external pressures to which they will be subjected. It is as true of a pipe as of a truss, that when it is strong enough to give the requisite factor of safety, nothing is gained by having it stronger. Anything more than this means dead weight, which has to be paid for many times, first as material, and again and again in the costs of transportation and handling, until it reaches its place in the trench or on supports. In use it must be and remain tight against all leakage, and must sustain whatever is placed over or upon it, or suspended from it, without deformation or injury. Finally, in addition to meeting all the immediate requirements of service, it must possess qualities of durability which warrant a reasonable expectation of a long life of usefulness. The wise engineer no longer regards it as reasonable to depend upon mere bulk of its own material for the protection of a metal as readily impaired or destroyed by oxidation as iron or steel. The metal must have a coating which will be and remain impervious and indestructible. When all these conditions are met, we have as near an approach to the ideal tube as can be attained with the materials now available for their manufacture. Steel wed constructively, to the best advantage, meets these requirements most perfectly. Gold alone would do it better. If we search through the whole list of metals and alloys we find nothing available which so perfectly meets the requirements as a pipe material as steel. Mr. Hamilton Smith, Jr., in a paper on the expedients adopted on

Jan 1, 1891

By John Shelton

ONE of the heaviest burdens uselessly cast by our mineral land laws upon the holder of the title conveyed by a patent from the United States is due to the provision excepting known veins from land patented as placer. In many instances the expense of defending such titles from the assaults of the owners of lode locations made upon the theory that the veins so located were known to exist at the date of the placer application for patent has exceeded many times the value of the land in question. Neither the lapse of time, however long after the issuance of the patent nor repeated adjudications by the courts serve to quiet such titles or to prevent them from being questioned. In the passage of laws providing for the acquisition of title to the mineral lands of the United States, Congress provided that the title to known veins should not pass from the United States by a patent based upon a placer location. As construed by the courts, the law (Sec. 2333 R.S.U.S.) provides that the applicant for a patent upon a placer claim may, if any vein of sufficient value to justify the expenditure of money in its development is known by him to exist within the boundaries thereof, include in his patent application an application for patent upon the vein as a lode claim; and failure to do so is to be deemed a conclusive declaration that the applicant makes no claim to the vein nor to an area of surface ground extending for 25 ft. (7.6 m.) on each side of its middle or center. As to such vein and, such area of enclosing surface ground under the circumstances stated, the title remains in, the United States notwithstanding the issuance of a patent that purports to convey the entire surface of a described area and everything beneath it, excepting only the segments of veins the apices of which lie outside of such area. Such known veins with such area of enclosing surface ground are, of course, at any time, so long as they remain unlocated, subject to location and appropriation in the same manner as other veins upon the public domain. The history of the operation of this law in one district will serve to illustrate its effect generally throughout the mining regions of the United States. In the Butte district, the mineral that first attracted the atten-

Jan 8, 1919

By D. A. Stevenson, R. A. Burmeister

Single-phase silver antimony telluride has been prepared by zone-melting techniques using initial compositions of A new phase appears upon prolonged annealing of this material, but the reaction does not appear to be a simple eutectoid decomposition. A complete analysis of the phase equilibria is complicated by the slow kinetics involved. The Hall coefficient, magneto -resistance, electrical resistivity, and Seebeck coefficient are all sensitive to the presence of second phases. The low Hall mobilities measured for single-phase material indicate that the usual band theory is inadequate to explain the observed transport properties in the system. Density anomalies of up to 2.5 pet between measured and theoretical density were observed but are not conclusive evidence for a defect structure. COMPOSITIONS in the Ag-Sb-Te system have been studied previously by several investigators.1"18 The interest in this system arises from potential thermoelectric applications of alloys on the Ag2Te-Sb2Tes vertical section. Although the composition corresponding to the formula AgSbTe, has received most attention, it has been found to consist of more than one phase.7'8 A thorough understanding of the properties of this heterogeneous material has been impeded by both lack of knowledge of the properties of the homogeneous phases comprising it and the problem of analysis of transport properties in an inhomogeneous system. The present work describes the preparation of the homogeneous ternary phase and the corresponding electrical properties of both homogeneous and heterogeneous material. MATERIAL PREPARATION Most specimens for this investigation were prepared by encapsulating the elements in evacuated quartz tubes after which they were melted and homogenized in the liquid state. The ambient temperature was then dropped to 500°C and the resulting ingot zone melted. The growth rate, width of zone, stoichiometry, and number of passes have an effect on the resultant microstructure. Grains several centimeters in length were easily produced by this method. Other solidification techniques were also used, including uniform slow cooling of the entire specimen and rapid freezing. The microstructures of specimens produced by these techniques frequently differed appreciably from similar compositions prepared by zoning. A variety of nonequilibrium microstructures characterized by long needlelike particles resulted from the rapid-freeze method. PHASE EQUILIBRIA The lack of information on phase equilibria is a major difficulty associated with a comprehensive study of the Ag-Sb-Te system. Considerable confusion has resulted from the use of the formula AgSbTe, to identify the cubic ternary intermediate phase even though it has been established that material of this stoichiometry normally contains AgzTe as a second phase.798 In this paper, silver antimony telluride will denote the cubic ternary intermediate phase comprising the major portion of AgSbTe,. The term "single phase" will denote material which consists of only the cubic phase (as evidenced by metallographic examination and X-ray diffraction) and the term heterogeneous will describe multiphase material containing AgzTe, SbzTe3, or other phases in addition to the cubic phase. The single-phase material may actually contain a variety of inhomogeneities—gradual changes in composition on a macroscopic scale, localized fluctuations in composition, clusters or other products of early stages of the precipitation process, and a variety of point and line defects—all of which will not be detected by the present techniques for determining homogeneity. Single-phase material has been prepared from compositions close to 59 mole pct SbzTe3 21 (this notation refers to the location on the Ag,Te-Sb2TeS vertical section). Zone widths of =2 cm and growth rates 51.2 cm per hr were used. The single-phase region at elevated temperatures extends off the vertical section to a composition which can be expressed approximately as Ag,,SbzgTes,.9 The latter two compositions as well as AgSbTe, are represented in the conventional Gibbs triangle in Fig. 1. It is not presently possible to ascribe exact values to the limits of the single-phase region on a given isotherm or vertical section due to the extremely

Jan 1, 1964

By Michael Hoch, Walter C. Wyder

The isothermul section of the Nb-Ti-Zr-O system at 1500°C was investigated using X-ray dzffraction and metallographic techniques. UP to 66.7 at. pct 0, the system contains nine four-phase regions. Tsopleths at 10, 20, 30, 40, 50, and 55 at. pct 0 weye constructed. The purpose of this investigation was to determine the general shape of the quaternary equilibrium phase diagram of niobium, titanium, zirconium, and oxygen at 1500°C. The system was truncated at 66.7 at. pct. O., PREVIOUS INVESTIGATIONS The Ti-Zr-O system was investigated in this laboratory.' The binary systems of interest have been compiled and discussed by anssen2 and Levin, McMurdie, and Ha11. Elliott4 has determined the Nb-O system by metallographic and X-ray diffraction techniques. He shows the existence of three oxides, namely NbO, NbO2, and Nb2O5. At 1500°C the solubility of oxygen in niobium is about 4 at. pct. No solid solubility region is shown for either NbO or NbO2. EQUIPMENT The same equipment as that for the study of the Ti-Zr-O system was used. The X-ray diffraction patterns were analyzed with the help of the ASTM card set5 and NBS circulars.6 MATERIALS The niobium powder (99 pct pure), the titanium powder (99.6 pct pure), the niobium pentoxide, and the zirconium dioxide used in this study were purchased from the Fairmount Chemical Co., Newark, N.J. The zirconium powder (99.4 pct pure) was obtained from the Charles Hardy Co., Inc., N.Y. Reagent-grade titanium dioxide was purchased from the Matheson Co., Inc., Norwood, Ohio. The oxides were dried in air at 700°C for 24 hr before use. Though the materials used were not "hyper-pure," the impurities present do not affect the results (lattice parameters, phase boundaries), within the experimental accuracy. PROCEDURE Samples of the desired compositions were made up, in mole pct, from the materials listed above. In some cases the intermediate binary compounds, such as NbO and TiZrO4 were prepared beforehand and used in the preparation of the samples. This technique enabled equilibrium to be reached from two sides. The components of each sample were mechanically mixed in a mortar and pestle and pressed into 3/16-in. diam pellets. The pressures used in compacting were of the order of 50 to 100 x 103 psi. Sintering was accomplished by heating the samples in a tungsten crucible (3/4-in. high, %-in. diam, 1/8-in. wall, lid with XB-in. hole). The pellets were separated from each other and from the crucible by means of small spiral coils of tungsten wire placed between the stacked pellets and on the bottom of the crucible. The sintering time was from 4 to 12 hr at 1500°C under a vacuum of 6 x 101-5 to 1 x 10-6 mm of Hg. All samples were reground after the first or second heating repressed, and reheated. In most cases: equilibrium was obtained after the first heating, as the X-ray diffraction pictures after each heating remained unchanged. Quenching of the samples from 1500°C was at first only possible by allowing the crucible and its contents to lose heat by radiation. The temperature dropped from 1500° to 900°c in approximately 1 1/2 min, which was considered adequate when compared to the times used by other investigators to reach equilibrium in the temperature range of 1000°c and lower. Later, a new technique for faster quenching of the samples was cleveloped. This technique involved the removal of the samples from the crucible, whereupon they were quenched by coming in contact with the water-cooled copper base of the furnace. This manipulation was performed without breaking the vacuum. The sample pellets were placed on a tungsten wire rack inside the crucible. The wire rack passed through the hole in the crucible lid, where it was connected to a small nonmagnetic chain. The chain was fed to the side of the furnace by means of a brass rack which fitted between the body and lid of the furnace. Suspended at the end of the chain, near the furnace wall, were three magnetic washers. With the use of a strong

Jan 1, 1962

By A. L. Holley

There is a growing demand for pure and cheap material for fine open-hearth steel; a material not only very free from phosphorus, but from carbon and silicon; so that it may he rapidly converted into steel. Iron and steel scrap are not trustworthy as to quality, and they are often dear. There are three methods of purifying cheap materials for the open hearth. 1. Mechanical puddling, as done at Creusot, which removes 90' per cent. of the phosphorus from the pig iron. 2. Krupp's washing process (the conduct and results of which 1 fully described in a former paper*), which eliminates 70 to 80 per cent. of the phosphorus and most of the sulphur and silicon from pig iron. Neither of these processes would sufficiently purify, for very fine steel, those very impure pigs which are cheapest in many parts of the United States. 3. The process of producing directly from the ore an iron which is practically pure chemically, although mechanically mixed with the impurities of the ore. This is the oldest of iron processes ; one form of it, the CataIan forge, employed to produce charcoal blooms, is still in use, but its great cost is rapidly throwing it out of competition. Among the modern attempts to produce iron direct from the one, on a large scale and at a cheap rate, several have been in various respects successful. Dr. Siemens's process of treating a ton and a half or more of ore and the coal to deoxidize it, in a rotating gas furnace, and bringing out, in some four hours, a ball of chemically pure iron so soft that the fluid and impure slag may be sqneezed out of it, is the most attractive and the most highly developed of all the modern direct processes. I hare watched it, from time to time, since 1874, and have noted a steady improvement. It may now be said to have passed the experimental stage, although, like older processes, it must be adapted by practice to special materials. The cause which has been more potent than all others, including the defects of the best direct processes, to bring these processes into disrepute, is the wasteful treatment of the direct product. With one or two exceptions (when failure mas due to other and obvious causes), the direct product has been made into wrought iron (weld iron). Even Dr. Siemens has, at Towcester, in England, and at Park, Bro. & Co.'s, in Pittsburg, set up his apparatus for this purpose. Is it likely that

Jan 1, 1880

By R. H. Johnson

All strata not yielding oil or gas in commereial quantities or a corresponding amount of water may be called dry in a wide sense. In petroleum geology, however, we may exclude all sands of too low or fine porosity to yield gaseous or fluid contents to the hole drilled in the sand before any original pressure that its contents may be under is disturbed. Most rocks are of this class and they are not reservoirs in our definition; their "dryness" is wholly a matter of course. What are the contents of the pores or what is the exact porosity of such rocks is of almost no concern to us, for economically they are "dry." What does interest us is the content of a rock having sufficient porosity and the pores of sufficient size to yield oil or gas in commercial quantities, if they were present under original pressure. Dryness of these reservoirs is a matter of supreme practical importance. Three views current as to such dryness seem, to me, to apply in a few cases only. It is the purpose of this paper to give reasons for this position and for believing that, in ordinary sedimentary rocks, there is only rarely a reservoir of competent porosity and undisturbed pressure that is dry in the sense of not yielding water, oil, or gas when first penetrated. 1. Gardnerl writes of some Kentucky sands, "There has never been present any salt water or other water in the sand." Absence of water cannot demonstrate this position. It is necessary to show that the rocks were not laid down in water, but in air, and that they became so enclosed, while still above the water-table of the ground water, that water has not been able to enter since. Most of these sands, and certainly the productive limestones, were deposited in water; and such sands as have been commercially productive show no reason for believing that the overlying shale or limestone was not laid down progressively from one direction and in water that would have flooded it. NO adequate explanation has been offered for this hypothesis, which is so inherently improbable. 2, Reeves2 urges that "sands originally water filled may have been drained of their water and not filled when later covered." It is difficult I James H. Gardner: Kentucky as an Oil State. Science, N. S. (1917) 46, 279-280. Reeves: Origin of the Natural Brines of Oil Fields. Johns Hopkins Univ. Circ., N. S. (1917) N. 3; Absence of Water in Certain Sandstones of the Appalachian Field. Econ. Geol. (1917) la, 354-378.

Jan 1, 1921

By Neil O. Johnson

In the cyanidation of gold, silver and mixed ores, the solids, suspended in the pulp after fine grinding, primary settling and scries agitation arc subjected to a washing step known, generally, as countercurrent decanta-tion, abbreviated C.C.D The conventional C.C.D. plant consists of a series of separate thickeners—three to five in number—arranged in series on slightly different elevations. Solids settled in the first thickener are pumped at maximum density into the second thickener, where they arc diluted with weak solution overflowing the third. After settling in the second thickener they are pumped to the third, where the process of repulping with still weaker solution is repeated, and so on throughout the system, until they reach the last thickener and are repulped with barren solution or water. Recently there has been developed a new type of thickener, known as the Dorr Washing Tray Thickener, consisting of up to five individual thickeners, which performs in a single unit all the functions of a conven-tional C.C.D plant. Fig. 1 illustrates the essential features. It is a multicompartment tray thickener, in which the trays operate in scries instead of in parallel for countercurrent washing. Feed enters the top compartment via a central, semisubmerged feed well. Strong solution overflows into a peripheral launder. Solids settle to the bottom, are raked to the center and flow into the top of the second compartment, directly below, via an inverted cup and scal. Solids pass downward, compartment by compartment, against a counter flow of wash solution and finally of fresh water. Thus, in accord-:trice with the basic C.C.D. principle, the solids transfer the dissolved metal content to the wash solution and finally are removed by a diaphragm pump from the bottom compartment virtually free of valuable material. Similarly, the wash water, as it flows through the system, becomes increasingly enriched in dissolved metal until it overflows from compartment two and returns to the process.

Jan 1, 1939