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By L. E. Mannion

Sodium carbonate (soda ash) is one of two principal commercial alkalis. Its principal competitor is sodium hydroxide. The use of sodium carbonate is recorded in ancient Egypt, where naturally occurring brines and solid salts provided impure soda for early glassmaking. Until the 19th century, soda ash (as well as potash) was recovered mainly by leaching wood or other plant ashes. In 18th-century Europe, for example, leaching seaweed ash with hot water produced a brown laundry lye. One of the better grades of this material was a Spanish product, barilla, which analyzed 24 to 30% Na2CO3 (Hou, 1942). The modern chemical industry was born in 1691 with the LeBlanc process for making sodium carbonate from salt, sulfuric acid, and lime. English industry used this process extensively in the 17th and 18th centuries. The next major advance was in 1863, when Ernst Solvay devised the ammonia-soda, or Solvay process. The first of many Solvay plants was built in 1874. These supplanted the LeBlanc method and dominated worldwide soda ash production until 1974, when mined sodium carbonate became predominant. Although considerably less important until recently, natural sodium carbonate deposits historically have supported small soda ash operations throughout the world. Shortages during World War II stimulated production of "natural" soda ash from such deposits, particularly at Searles Lake, CA and Lake Magadi, Kenya. More spectacularly, increased production from the vast trona deposits in Wyoming has virtually supplanted the Solvay process in the US. Principal producers of natural soda ash as well as the character of the source deposits are listed in Table 1. [ ]

Jan 1, 1983

By Robert Bosworth

THE liability for damages to the surface caused by subsidence is an ever present threat in all underground mining. In ordinary lode mining, this threat rarely materializes into an action, due to the method of mining metalliferous ores, the dip of the veins, and the nature of the ground itself. In the mining of coal, however, this threat is very real. The coal frequently lies close to the surface, in beds underlying large areas of land of which the surface is suitable for: agricultural or urban development. Furthermore, the coal is generally mined by the "room and pillar" method and when the pillars of coal are removed, the subjacent support is destroyed. This question of the duty of surface support has now become a very live one in Colorado. What was waste prairie land a few years ago has become valuable agricultural land dotted here and there with growing towns. Frequent references will' be made here to Colorado conditions and adjudicated cases, but those conditions and cases and the conclusions to be drawn therefrom are applicable to all coal-mining states. Briefly stated, the question is "Does the owner of the substrata or underlying mineral owe any duty of surface support to the owner of the superjacent strata or surface?" There is no absolute duty of support owed by the mineral owner and this assertion is made with full knowledge of numerous expressions to the contrary by courts of Pennsylvania, Illinois, Colorado and other coal-mining states. Whether or not any duty exists depends upon the circumstances surrounding each case, and since in the nature of things those circumstances are rarely identical, there can be no absolute rule.

Jan 1, 1928

By F. C. Frischknecht

Most early development and application of electromagnetic prospecting methods took place in Scandinavia, where geological conditions favor their use. In other parts of the world these methods have aroused cycles of interest, but in Scandinavia they have been used continuously and successfully since the 1920's. Electromagnetic methods may be classified into two general groups. One group includes methods in which the source of the electromagnetic field remains stationary while the receivers are moved about to explore the area. The other includes procedures in which the energizing and receiving systems are moved together. Other classifications could be based on the size of the energizing source, the particular components of the electromagnetic field which are measured, or the mode of transporting the equipment. The difference between fixed-source and moving-source methods, however, is of such great fundamental importance that it will be emphasized in this discussion. FIXED-SOURCE METHODS Essentially, a fixed-source method consists of the measurement of electromagnetic fields about the source. The mutual coupling between the source and the earth is constant, but the mutual coupling between the receiver and the earth (unless the earth is homogeneous) and also between the source and the receiver changes at each station. The results are usually normalized by relating the field data to the calculated free space or primary field. Turam and Radio Reference Signal Methods: The turam or two-frame* (see Fig. 1A) is probably * Turam means two-coil. the most common fixed-source method. The energizing source is an insulated cable grounded at both ends or formed into a large rectangular loop. Measurements are taken along a traverse at 5 to 50-meter intervals using two small receiving coils, the lagging coil being placed at the position previously occupied by the leading coil. The complex ratio (i.e., inphase and out-of-phase ratios) of the voltages induced in the two coils is measured. Operating frequency range is about 100 to 800 cps. In a typical turam survey a straight, grounded cable several kilometers long is laid out parallel to the probable strike of the ore deposits or conducting strata being sought. An area extending 1 or 2 km on each side of the cable, and within 1 or 2 km of the ends of the cable, is surveyed. Measurements are made at stations 5 to 25 m apart along traverses perpendicular to the cable. Measurements may be made along lines parallel to the cable to serve as base lines for the traverses or for other special purposes. Commonly the receiving coils are oriented with their planes horizontal so that only the vertical component of the field is measured. If additional information is required, one of the hori- zontal components may also be measured by orienting the coils with their planes vertical. In a modified turam technique developed recently for both ground and airborne measurements (Fig. 1B) the amplitude of the complex voltage induced in a single receiving coil is measured and its phase compared with that of a reference signal transmitted from the energizing system by a radio frequency carrier. Thus the un-normalized field is obtained directly, whereas with the turam method it is obtained by calculation from the ratios. The turam method and its modifications have a greater working depth than the other electromagnetic procedures used in ore prospecting. Under favorable conditions conductors have been located at depths of 200 to 300 m. A modified turam method with one of the electrodes grounded in the upper end of a plunging orebody was used to follow the extension of this body to a depth of 200 m beneath a layer of conducting schists. Straight grounded cables are usually preferred to insulated loops because they are easier to lay out and because they often make the method more sensitive. The greater sensitivity of a grounded cable is a result of ground return currents which may flow in the orebodies in addition to the eddy currents caused by induction from the current in the cable. Anomalies in the vertical field due to eddy currents are characterized by a correspondence between high values for the inphase component and positive out-of-phase components and/or low values for the inphase component and negative out-of-phase components. Also the inphase component may approach zero, but it does not become negative. In very long continuous conductors that are parallel to a grounded cable the effect of ground return currents may far exceed the effect of eddy currents. These ground return currents cause a lack of correspondence between the inphase and out-of-phase components and may cause negative inphase or anti-phase components. It becomes difficult to carry out the measurements and often difficult to interpret the results. Such results immediately suggest the presence of graphitic strata, however, since ore deposits are rarely extensive enough to accumulate sufficient ground return current to cause these results. A cable laid out perpendicular to the strike or an insulated loop is sometimes used in areas where graphitic schists and slates are present. Anomalies are then completely or almost entirely due to eddy currents and are easier to interpret. The measured voltage ratios are normalized by either subtracting or dividing by normal field ratios calculated from free space considerations. The normalized ratios are then plotted as individual profiles. When significant anomalies occur in the ratio measurements, the actual normalized fields are calculated by beginning with a measured or an assumed value for the field at a point near the cable and successively multiplying this value by the normalized ratios. There is a similarity between this process and a numerical integration of the ratio curve. Conversely, in many respects the ratio curve is similar to the first derivative of the field curve.

Jan 1, 1960

By W. F. Stowasser

downdraft traveling grate process to agglomerate pelletized iron ore concentrates has been successfully demonstrated in a pilot plant at Carrollville, Wis. Work there followed several years of development in the Allis-Chalmers Mfg. Co. laboratories, and the pilot plant phase was carried out in cooperation with Arthur G. McKee & Co., consultants and engineers to the iron and steel industry. End result of the process is conversion of iron ore concentrates into a form which can easily be transported and smelted in the blast furnace. Process Description The first of two process steps incorporates the art of balling and prepares the concentrates for burning. The second step consists of burning the green balls on the grate machine to the hardness required for shipping and handling purposes and for reduction in blast furnaces, see Fig. 1. Facilities are provided at the pilot plant to receive carload quantities of concentrate. The concentrates are loaded into a 50-ton bin direct from railroad cars. Because of the variable moisture content of the concentrates after shipment in an open railroad car it is necessary to repulp and refilter the concentrates to maintain a uniform and proper moisture content for the balling operation. Concentrates are conveyed to slurry tanks, and the slurry, at 50 to 60 pct solids, is pumped to a 4x4-ft drum filter. The filter provides feed of uniform moisture to the plant. Magnetite concentrates are normally filtered to produce a cake containing about 10 pct moisture, a necessary requirement for the following balling operation. The filtered concentrate is conveyed to a rotary bin table feeder which acts as a surge bin for the filter cake and delivers a steady flow of concentrates to the balling drum. It is often desirable to make additions to the concentrates as they are fed to the balling drum. These additives, such as bentonite, increase the strength of the finished green pellet and improve ballability of the concentrate. A vibrating feeder supplies additive to the feed belt, and the additive is mixed with the concentrate in the balling drum. The balling drum, shown in Fig. 3, is 8x3-ft diam. An oscillating cutting bar maintains the lining in the drum by trimming off the buildup of excess concentrate as it forms. The drum is operated in closed circuit with a lx4-ft rod-deck vibrating screen. Undersize pellets or seed pellets from the screen are returned to the balling drum until they grow to the desired size. Size of pellets is controlled by the opening in the screen deck. The formation of pellets in the balling drum is affected by many variables. Some of these are: the size distribution of the feed, the particle shape of the concentrate, the feed rate to the drum, the moisture in the concentrate, the speed of rotation of the drum, the slope of the drum, and the type of trimming obtained with the cutting bar. In this process, attempts are made to control the pellet size within the limits of % to 5/8 in. diam. The screened oversize pellets are conveyed under a coal feeder where sufficient powdered coal is added to the belt to produce desired results in the burning process. The top size of the coal successfully used has been 20 mesh, and anthracite was used in the test program. Fig. 4 illustrates the vibrating screen and the coal feeder. The pellets and free coal are conveyed together to the 5x3-ft diam- reroll drum that rolls the coal onto the surface of the pellets. This drum is also equipped with a cutting bar. The prepared pellets, containing bentonite, water, and surface coal, are elevated to the traveling grate, which consists of a continuous strand of 37 pallets. Each pallet, with a grate bar area 2 ft wide by 1 1/2 ft long, has 14-in. high side plates, Fig. 5. Feeding and distribution of the green balls to the grate is handled by a short conveyor which oscillates back and forth across the 2-ft width of the grate. An adjustable vertical plate located several inches in front of the head pulley of the oscillating conveyor controls the height of the bed and levels the moving bed of pellets. This method of feeding prevents segregation of various size pellets as well as fines and produces a uniform, permeable bed. The pallet train moves under the furnace and across four windboxes, located beneath the pallet frames, see Fig. 2. As the green pellets are deposited on the grate, partial drying of the pellets begins over a 2-ft long updraft windbox. The low temperature air reduces the moisture in the pellets in the lower level of the bed and this operation is essential to prevent sagging of the bed during later stages of the Process. The air used for this drying is recuperated from cooling the pellets on the grate, and supplemental heat, required for starting the Process, is obtained from an auxiliary burner. The pellets are then moved by the grate into the furnace and over an 8-ft windbox, designated as the downdraft waste windbox. Products of combustion are exhausted from this windbox to atmosphere. The furnace, shown in Fig. 6, is constructed with three chambers to provide downdraft drying, preheating, and ignition, respectively, to the pellet bed as it passes through. Overall length of the furnace is 5.57 ft; however, the exterior wall ends may be moved to reduce the length and also adjusted to Obtain the bed height desired, The drying, preheating, and ignition sections of the furnace are supplied with medium temperature

Jan 1, 1956

By G. H. Gronhovd, W. H. Oppelt

Complete gasification to produce synthesis gas for manufacture of synthetic chemicals and fuels offers possibilities for utilization of the vast lignite fuel deposits in the U.S. The design of a slugging, fixed-bed, pressure gasification pilot Plant is described. Results are presented for initial operation of the plant at moderate pressure and using low-temperature char as fuel. Gasification of solid fuels is becoming increasingly important in the future overall energy picture, both in this country and abroad. Snythesis gas from gasification of coal consists chiefly of carbon monoxide and hydrogen, and after suitable purification and modification this gas can be used in the production of synthetic ammonia, methanol, higher alcohols, and synthetic liquid fuels, or as a reducing gas in the metallurgical field.' Most synthesis gas used in this country is made from natural gas, petroleum oils, and refining tail-gases, but the direct gasification of coal will become more attractive as costs of petroleum oils and natural gas increase.' A gasification process designed for use with brown coal and lignite was developed by the German Lurgi Co. prior to World War 11. In this process a fixed bed of lump-sized fuel is gasified with steam and oxygen at pressures ranging from 370 to 440 psi. Effective heat exchange between the ascending high-temperature gases and the descending solid fuel results in low gas outlet temperatures, high thermal efficiency, and favorable oxygen consumption. Lurgi gasifiers are used commercially for the production of synthesis gas or as a substitute for coal gas in many countries, including Germany, Czechslovakia, Great Britain, South Africa, Australia and Pakistan.3-6 The chief disadvantage of the conventional Lurgi gasifier which operates under nonclinkering conditions is that large quantities of excess steam must be supplied with the oxygen-steam mixture to reduce the temperature in the fuel bed below fusion temperature of the ash. Most of the steam leaves the gasifier undecomposed with the product gas and, after cooling, produces large amounts of dilute liquor. Evaluation of fixed-bed gasification experiments using dry-ash removal indicated that by increasing the oxygen concentration in the oxygen-steam blast the temperature in the combustion zone could be raised high enough to operate under slagging conditions. 7-8 Operation of a fixed-bed pressure gasifier under slagging conditions would reduce the steam requirements and the volume of waste liquor and would increase the steam decomposition, the overall thermal efficiency of the process, and the rate of gas production per unit cross sectional area of the gasifier. Because the Lurgi gasification process, modified for slagging operation, offered possibilities for efficient gasification of American lignite, the Bureau of Mines decided to investigate the process on a pilot-plant scale at the Grand Forks, N. D., Lignite Research Laboratory. DESIGN Description of Pilot Plant: A flowsheet of the Grand Forks slagging gasification pilot plant is presented in Fig. 1. The gasifier unit consits of the coal lock, the gas generator, and the slag lock. The fuel, which is periodically charged to the coal lock, moves by gravity flow into the generator and is continuously gasified by an oxygen-steam mixture introduced at the bottom of the gasifier. Molten slag is formed at the hearth and flows through a central taphole into a water quench bath. The slag-water slurry is periodically discharged from the slag lock. Process steam is generated and superheated in separately-fired, oil-burning units. Oxygen is supplied to the gasifier from a gas storage bank located some distance from the pilot plant. The capacity of the oxygen storage bank is about 130,000 standard cu ft at 2200 psig. Liquid oxygen is delivered by truck and is converted to gas during the filling operation. The superheated steam and oxygen are metered separately, then mixed and fed to the gasifier tuyeres. The gas generator is surrounded by a water jacket. The steam formed is separated in the steam drum and then discharged to the gas offtake, thus equaliz-

Jan 1, 1961

By W. E. Keck

THE potential iron ores of Michigan can be classified from the stand-point of the predominant impurities into siliceous, sulphurous and phos-phorous ores. Research on the flotation of each of these classes of ore was carried out in the following Planner. The flotative properties of the valuable minerals of iron and of the worthless and deleterious ones were first determined under carefully controlled conditions. This information was then applied to synthetic mixtures of these minerals, which simulated the potential ores. Finally, data obtained during the two foregoing stages of the investigation were used in the flotation beneficiation of samples of the potential ores. Hematite is the most important mineral of iron in each of the above classes of iron ores. This paper deals with a study of that mineral in the very nearly, pure state. There are two varieties of the mineral-specular hematite and massive hematite. The latter is the principal variety, but the former is an Impor-tant mineral of iron in some of the potential ores. Because of this condi-tion, flotation research was performed with both varieties. This research consisted essentially of: (1) a survey of the literature on hematite flota-tion, (2) the preparation of pure massive hematite, (3) the preparation of pure specular hematite, (4) the; development of a laboratory procedure and (5) flotation experimentation. For the purpose of this discussion, the results of previous work on the flotative properties of hematite can be summarized as follows: Specular hematite has been readily floated with terpineol and sodium oleate or heptylic acid1. Further, hematite has been likewise floated with a pro-prietary frother and oleic acid or other soluble oils 2. Finally, lead nitrate, copper sulphate, silver nitrate, chromium nitrate, mercuric chloride, ferric

Jan 1, 1937

By A. L. Holley

The application of scientific methods to the investigation of natural laws and to the conduct of the useful arts which are founded upon them, is year by year mitigating the asperity and enlarging the outcome of human endeavor. More notably, perhaps, are these the facts in that system of productive and constructive arts of which engineering is the general name. In metallurgical engineering especially, within the period of our own recollection, how rapid has been the rate and how wide the scope of progress: the scientific discovery and mining of metalliferous veins; the economical separation and reduction of ores of every grade; the production and regulation of high temperatures; the varied improvements in the manufacture of iron, in saved heat and work, in uniformity and range of products; and, most important of all, the creation and the utilization, to be counted by the million tons a year, of the cheap constructive steels. Wonderful as this range and degree of development may appear to the public eye, the close and thoughtful observer must, nevertheless, conclude that neither the profession nor the craft of engineering may congratulate themselves too complaisantly, but that they should rather acknowledge to each other the embarrassing incompleteness of the union between engineering science and art. There is a small school of philosophers whom we may designate as original investigators, men who come close to nature, who search into first principles, and who follow that scientific and therefore fruitful method by which the relations of matter and force are discovered, classified, and brought within the reach of practice. These wonderful men do not indeed create the laws of nature, as they sometimes almost seem to, but they go up into the trembling mountain and the thick darkness and bring down the tables upon which they are written.

By Arthur Phillips, E. S. Bunn

During the past few years considerable interest has been shown in the study of fiber, and its effect, in wrought metals. Fiber has recently been defined as a "condition of parallelism of important lines or details in the structure."' Briefly stated, two distinct types of fiber are commonly encountered. One results from the alignment in the direction of working of constituents, more or less segregated, such as slag, oxides, carbides and dendritic formations. The second, and least understood, type is produced by working the metal below the recrystallization temperature in such a way as to develop a parallelism of the grains. This condition is readily recognized by the pronounced elongation of the grains in the direction of working. Under certain deformational treatments the grain fragments produced by cold working tend to orient in certain definite directions with respect to the axis of extension. Furthermore, even in metals that have been annealed after cold working preferred orientations may be present. It is perhaps logical to assume that such marked parallelism of structural elements would be manifested by directional properties in the metal. As a matter of fact, tests on many kinds of materials have shown differences in varying degrees. In recognition of this condition, proper design, for many purposes, places the fiber axis in such a way as to present the direction of maximum strength to the greatest applied stress. Earlier Investigations Howe2 has written at considerable length regarding the causes and practical significance of fiber in steel and wrought iron. His studies showed that wrought iron and the puddled steel sheets (materials of plastic origin) were weaker transversely than longitudinally. The transverse deficit ranged from 5 to 29 per cent. The longitudinal tests

Jan 1, 1931

By Klaus Schoenert

In the analysis of comminution processes, it is necessary to have a detailed knowledge of such subprocesses as: transportation of the particles to the zone where they are stressed; the stressing of particles to a level high enough for breakage; removal of the fragments that are smaller than the limit size from the grinding zone; and prevention of agglomeration of the fine fragments. Breakage phenomena of particles is the most difficult subprocess to understand. It can be understood only by applying the principles of fracture physics to obtain information about the stress-strain field in particles which are loaded either by compression or by impact, and by using this theoretical knowledge to interpret experimental results obtained from single particle crushing studies. Two important features of the "Science of Communition" are discussed: the fracture physics and crushing under controlled conditions with special reference to single particle crushing, packed bed crushing, measurement of energy needed for fracture, fragment size distribution, and new surface area produced. The important features of these aspects are detailed, namely, energy balance of a crack, influence of environment, specimen size problems, and energy utilization in single particle crushing.

Jan 1, 1973

By John A. Emery

The Pea Ridge iron ore deposit near Sullivan, Missouri, is a dike-like mass of magnetite enclosed in Precambrian porphyries. The ore body tops at the Precambrian surface at a depth of 1300 feet below the present surface and extends to an unknown depth. It dips nearly vertically, intersecting the dip and strike of the enclosing porphyries at an extremely sharp angle. Faulting, both pre- and post-ore, appears to be of minor consequence, and present knowledge indicates that no preferred structural conditions existed prior to emplacement. The ore body is composed of magnetite with specular hematite, quartz, apatite, and pyrite occurring as accessory primary minerals. Specular hematite in appreciable quantities occurs on parts of the cap and the footwall of the ore body. Fresh porphyry breccia is enclosed in the magnetite along the hanging wall and in the western portion of the ore body. Hanging-wall quartz-amphibole and footwall quartz-hematite occur as replacements of certain porphyries. Further alteration has caused sericitization of parts of these zones. The ore deposit is interpreted as having been formed essentially by a single injection of a magmatic differentiate with hydrothermal end phases forming the quartz-amphibole and quartz-hematite portions of the deposit.

Jan 1, 1968

By W. H. Herrnstein, J. B. Clark, E. C. Utley, A. J. McEvily

The ratio of the endurance limit (10' cycles) to tensile strength of age-hardened aluminum alloys is approximately 0.3, whereas the ratio for annealed alloys is about 0.5. The lower value for the age-hardened alloys has been associated with the instability of coherent precipitate during cyclic loading, but it has not been definitely established whether this instability is due to overaging or reversion during cyclic loading. The results of the present investigatzon support the reversion viewpoint. In this work specimem of 2024-T4 aluminum alloy were aged for 16 hr at 150°C after cycling for 10 pct of the life at 25.000 psi. These specimens were then tested to failure and exhibzted a marked increase in fatigue life. It is proposed that during the early stages of fatigue in this alloy dislocations cut through the coherent precipitate and bring about the reversion of the precipitate. Subsequent aging at 150ºC induces reprecipitation in the precipitate-free zones so that the weakened regions are strengthened and the fatigue life is extended. It Is recognized that the fatigue strengths of precipitation hardened aluminum alloys are unusually low relative to their tensile strength.'-= This feature is illustrated in Fig. 1 where it can be seen that age-hardened alloys have lower fatigue ratios (the ratio of the fatigue strength to the tensile strength) than those in the annealed or cold worked state. Further, as shown in Fig. 2, the more an alloy is dependent upon precipitation hardening for its total strength, the lower is the ratio of the fatigue strength to the tensile strength. This state of affairs has been associated with an instability of the metastable metallurgical structure of precipitation hardened aluminum alloys during cyclic loading. Evidence2 in support of this view is that the fatigue ratio increases in these alloys as the test temperature is lowered, thereby indicating that thermo-mechanical instability, rather than some other factor such as a non-uniform distribution of precipitate, is the factor responsible for the low fatigue ratio at room temperature. Two mutually exclusive proposals have been ad- vanced to account for this instability. Hanstock has proposed that overaging takes place during cyclic loading, and in support of this view, Broom et a1.2 have indicated that an overaging process might be promoted by the large numbers of vacancies which are created during cyclic loading. The creation of vacancies by radiation4 has been shown to lead to rapid overaging. Hanstockl obtained visual evidence of overaging in an aluminum alloy after cyclic loading, but in this instance it has been pointed ou? that because of the high frequency used (60,000 cpm) the observed effect may have been due to normal high temperature precipitation around energy dissipating cracks. Efforts to discern visual evidence of overaging in this alloy at lower test frequencies were not successful.3 The alternative postulate3 is that reversion takes place during cyclic loading and leads to localized soft spots at which fatigue cracks are readily initiated. Evidence for this process has recently been provided by Polmear and Bainbridge5 who demonstrated metallographically that regions depleted of precipitate were created during cyclic loading of an aluminum alloy. Inasmuch as precipitate particles bordering the depleted region had not grown in size, it was concluded that the solute atoms which had constituted the missing particles had gone back into solution. No mechanism for the reversion process was presented. The present study was undertaken to investigate further the conditions leading to instability during cyclic loading, and to determine whether reversion or overaging had taken place as a result of cyclic loading. BACKGROUND AND TEST PROCEDURE In order to differentiate between the processes of reversion and overaging, rest periods at an elevated temperature, which ordinarily would insure additional precipitation, were used in this investigation. It was expected that after a period of cyclic loading an elevated temperature rest period would result in a decrease in the remaining life of the specimen if overaging were occurring during cyclic loading, whereas in the case of reversion, reprecipitation would occur and the fatigue life would be extended. Such an expectation is based on the assumption that the crack-nucleation phase is a significant portion of the total fatigue life, and that such a treatment is of influence in the crack-nucleation stage and is relatively unimportant thereafter.

Jan 1, 1963

By Charles M. Behre

Under the caption "fault," geologists intend to include all mass movements of solid rocks over adjacent rock masses. When these are studied long after their origin, however, circumstances make it possible to recognize as "fault" only formations showing clear evidence of actual movement of one side with respect to the other. Necessarily the chief evidence consists of the offset of a vein, bed, or other key structure. Planes of movement parallel to the bedding, or nearly so, are recognized with difficulty or are overlooked and hence many important faults are wholly unrecorded. Indeed, among standard American references on structural geology, one alone emphasizes the importance of bedding-plane movements and that one only briefly1. For some time the writer, cognizant of this difficulty, has paid special attention to such movements, both as observed in the field and as recorded in the literature. It is believed that enough data are now at hand to justify a short discussion. Its purposes are fivefold. It is desired first to briefly classify and describe at least the more common kinds of bedding-plane faults, and second, to examine the causes and manner of their formation, at least in instances where the subject has not yet been well covered by other investigators. Third, certain by-products of bedding-plane movements are of such conspicuous importance to the economic geologist and mining engineer as to merit mention. Fourth, concrete illustrations should be placed before the reader in order to lend reality and to furnish a basis of comparison with his experience; such illustrations will necessarily be scattered through the text of this paper. They are only in part from the writer's own field observations. The fifth and prime objective of this paper is to direct attention to the great importance of movements on the bedding planes, in the hope that the recognition of such movements and their significance may simplify mining problems.

Jan 1, 1937

By E. H. Fahmy, L. C. Uren

During recent years, oil producers have observed with interest the practical success which has attended the application of water as a medium for displacement of oil from its reservoir sands in the Bradford field of northern Pennsylvania and southern New York. Here, according to various authorities, additional recoveries of frorn 2,000 to 12,000 bhl. of oil per acre have heen secured by this method, after ordinary flowing and pumping. rnethods of production had practically reached the lower limit of economic operation. Notwithstanding the success which has attended the practical use of the flooding process in the Bradford field, oil producers in other regions are skeptical of its value when applied under physical conditions differing markedly from those which characterizc the Bradford field. Its usc would probably he construed as illegal in most of the oil-producing states. This general relnctance on the part of oil producers in other regions to accept the flooding process is due in large part to lack of infor-n~ation regarding the factors that influence its operation and efficiency. With the purpose of clarifying to some extent the issues involved, and of determining when the flooding proccess may or may not beeffee-tivcly ernployed, the writers have conducted a serics of laboratory exper-imentments under carefully controlled conditions, designed to indicate, the influence of various physical, chemical arid lithologic factors. These experments have not been conducted under conditions identical with those which exist at depths far below the earth's surface, so that direct quantitative comparisons with field results are not justified, hut it is believed that the experimental results at least warrant qualitative inter-pretations that may he applied to field conditions. The methods employed in the conduct of these experiments are briefly explained, and the results, together with the conclusions based thereon, arc presented. FactoRs Influencing Displacement of Oil froM SaNdS by WAteR- flooding Before presenting the experimental data, it, will he desirable to con-sider the manner in which the residual oil is retained within the oil sand

Jan 1, 1928

By William B. Phillips

The concentration of natural magnetites has been carried on in this country for several years, and more or less information has been collected on the subject. Various inventors, availing themselves of the magnetism which is inherent in such ores, have devised machines for separating the impurities from the ore by means of the electric current; and a greater or less degree of success has rewarded their painstaking and persevering efforts. We are now fairly in position to judge of the value of the process as applied to such material. It is not my purpose to speak of this matter further than may be required by the emergencies of the case. I shall assume that most engineers and metallurgical chemists are already acquainted with what has been done at the Chateaugay mines, at Mineville, at the Benson mines, at the Weldon and Ogdensburgh mines, and at Cranberry; although, at this latter place, there has not been so much done as we could wish. I shall not now speak of the various types of separators. From the time of William Fullarton, to whom was granted an English patent, in 1792, for separating iron-ore by the application of magnetic attraction, down to the present time, a great. many devices have been suggested, and a great many patents taken out for this purpose; but it is not necessary now to enter upon a discussion of their merits. Perhaps, at some future meeting of the Institute, after we shall have experimented further with some of the machines on the market, there may be an opportunity to contribute something to the current knowledge of the efficiency and economy of separating-machines. In this paper I propose to give, as briefly as possible, the results already reached in converting a non-magnetic ore into magnetic ore, and then concentrating it over a magnetic separator of the alternate-polarity type. I am aware of the work

Jan 1, 1896

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Trustees, Inc. When Mr. Carnegie made his gift which made possible a home for the engineering societies, a separate corporation was organized to act as a holding company and to manage the common property. This was long known as the United Engineering Society, but the name has now been changed. to one which more nearly reflects the real function of the corporation. It holds title to the Engineering Societies Building and to various funds placed in its charge and is managed by a Board of Trustees, of which three are chosen by each of the four societies, American Institute of Mining and Metallurgical Engineers, American Society of Mechanical Engineers, American Institute of Electrical Engineers and American Society of Civil Engineers, which have equal and undivided interests in the property. The land and building cost two million dollars. During the gear 1934, the constitution and By-laws of The United Engineering Trustees, Inc., were thoroughly revised and a better organization of its functions was affected: The Engineering Foundation and the Engineering Societies Library were made "departments? of the United

Jan 1, 1936

By J. B. Morgan

The mechanical behavior of MgCu2 from 20 o to 725°C has been determined by "brittle-ring" tensite-test techniques, axial compression, and bending experiments. Compressive ductility begins at 450°C (0.65 T/Tm) and slowly increases with increasing temperature white the tensile ductility is characterized by an abrupt brittle-ductile transition at 600°C (0.8T/Tm). The compressive strength increases eightfold from room temperature to 400°C with a "normal" decrease as the temperature is further increased. The tensile strength goes through a rather abrupt threefold increase above 600°C with a subsequent decrease at higher temperatures. The slip system is (111)[110] and the twinning system is (111)[112]. At high temperatures MgCu2 is quite rate-sensitive, and dynamic yield points are observed that are extremely orientation-dependent. The high-temperature creep behavior under constant load is characterized by an increasing strain-rate with time. The general characteristics of the mechanical behavior make it possible to classify MgCu2 with those materials in which initial mobile dislocation density and the dislocation velocity-stress dependence are significant in determining mechanical response. Mgcu2 is the C15 prototype of the cubic Laves phase. Its range of homogeneity extends from 32.8 to 35.5 at. pct Mg at 500°C and narrows at lower temperatures. The lattice parameter is reported to vary from 7.02 to 7.05A,1 and the compound is completely ordered to the melting point of 819°C. MgCu2 has a brassy metallic appearance, is extremely brittle, and many of its physical properties are intermediate between those of the constituent elements: the electrical resistivity is 3.5 x 10-6 ohm-cm, Young's modulus is 10x 106 psi, the shear modulus is 6 x l06 psi, and the thermal coefficient of expansion is 18.7 x 10-6 cm per cm per "C from 20" to 250°C. Usually, properties of intermetallic compounds as functions of temperature have been determined by hardness, compression, or impact behavior, and almost all of these experiments have been performed on polycrystalline materials. Tammann and Dahl,2 for instance, determined the onset of ductility in a series of binary intermetallics by ball-hardness measurements and found the onset to range between 0.71 and 0.96 T/T,. Lowrie's3 investigations included some tensile properties, and he found ductility beginning around 0.65 T/Tm for most materials examined. His work did include some data on polycrystalline, nonstoichiometric MgCu2, however. The present work is an attempt to extend the examination of the particular compound MgCu2 in single-crystal form in order to aid the formation of general concepts about mechanical be-

Jan 1, 1965

By H. L. Luo, P. Duwez, C. C. Chao

BY rapidly cooling alloys from the liquid state, it is possible to obtain solid solutions beyond the equilibrium concentrations, provided that the components are miscible in the liquid state. Typical such cases include CU-Ag,1 Pt-Ag,2 CU-Rh,3 nickel-base alloys with silicon, germanium, and tin,4 and cobalt-base alloys with silicon, germanium, tin, aluminum, and gallium.5 In the present note it is shown that terminal solid solutions can be appreciably extended in A1-Mg alloys. The alloys whose compositions are given in Table I were prepared by induction melting in tantalum crucibles under an argon atmosphere. Both aluminum and magnesium were 99.99 pct pure. Weight losses after melting were less than 0.2 pct for the aluminum-rich alloys and less than 0.4 pct for the magnesium-rich alloys. From these weight losses it was estimated that the compositions of the ingots after melting were accurate within 0.3 at. pct for aluminum-rich alloys and within 0.5 at. pct for magnesium-rich alloys. As indicated in Table I, the compound AuCd10 in which there is an ionic contribution to the bonding. The authors thank Dr. J. H. Westbrook of the Research Laboratory, General Electric Co., for arranging the supply of materials and for his interest. This investigation was supported by the U.S. Atomic Energy Commission under Contract AT(30-1)-1002, Scope I. some of the alloys were also chemically analyzed and the results confirmed the limits of uncertainty based on weight losses. Rapid quenching from the liquid state was achieved by techniques previously described.8,7 The principle of these techniques consists of propelling a small globule of liquid alloy (about 20 mg) onto a copper substrate. The thin foils easily detached from the copper substrate were analyzed by X-ray diffraction using a Debye-Scherrer camera 114.6 mm in diameter and either nickel-filtered copper Ka or iron-filtered cobalt Ka radiation. Since the back-reflection doublets were resolved, the wavelengths used in the computatioas were CuKal = 1.54050A and CoKa1= 1.78892A. Lattice parameters were obtained by extrapolation of the Nelson-Riley function, and the tables compiled

Jan 1, 1964

By H. S. McQueen

The insoluble-residue method for the examination and correlation of limestones and dolomites, or other sedimentary rocks containing calcium and magnesium carbonates, originated and was developed in the laboratory of the Missouri Geological Survey. The numerous and ever-increasing problems in the field of applied geology, and the need for a tool or aid in the solution of them, led to experimental work with samples collected from deep wells, in the early part of 1924. The success attained, almost at the outset, with this method was so great that the method has now been developed from the state of the experimental to the realm of large-scale, every-day routine. In a previous paper the writer1 described the procedure in detail and the characteristics of the residues obtained from certain Paleozoic formations in Missouri. The purpose of the present paper is to discuss the economic application of the insoluble-residue method. Developmental History Within the Ozark region of southern Missouri the geologic column consists of Lower Ordovician (Canadian of Ulrich) and Upper Cambrian formations, which are composed mainly of dolomite with subordinate amounts of sandstone, shale and limestone. Chert is found to some extent in all except one of the dolomite formations. The stratigraphy of the region is complex because the dolomites have lithologic similarities, fossils are few and often poorly preserved, and identifiable horizons within the comparatively thick formations are not common. Although considerable stratigraphic work of an areal nature had been done for a period of many years by the Missouri Geological Survey, the detailed geologic succession had not, until a few years ago, been systematically worked out. The problems of subsurface stratigraphy were even more complex. This region constitutes the main ground-water province of the State of Missouri and within it wells of varying depths are drilled in order to obtain supplies of ground water. In the work of the State Geological Survey in connection with the drilling of water wells for public supplies * Published with the permission of the Director, Missouri Geological Survey and Water Resources. Manuscript received at the office of the Institute Feb. 20, 1936. Assistant State Geologist of Missouri; Missouri Geological Survey, Rolla, Mo. References are at the end of the paper.

Jan 1, 1937

By W. L. Finlay

Size effects in quenching steel are particularly prominent and well recognized because of the existence of a critical cooling rate separating nuclea-tion and growth transformations, as exemplified by the formation of pearl-ite, from the shear type of transformation characterizing the martensite reaction. The absence of a similar, sharply demarcating cooling rate is characteristic of precipitation hardening systems and size effects in these are correspondingly less prominent. This paper is concerned with a size effect in high-purity, precipitation-hardenable alloys which appears not to have been recognized previously. This effect is believed to result from the thermal fluctuations which inevitably occur in quenching a specimen of finite size into a cooling liquid rather than from the existence of a critical cooling rate. QUENCHING "ANOMALIES" The precipitation hardening literature contains many references to so-called anomalous quenching and aging results. By "anomalous", investigators usually meant that their alloys did not consistently harden on aging after quenching according to some anticipated pnttern: not infrequently virtually no age hardening occurred with compositions known to be precipitation-hardenable. Perhaps the most prominent series of anomalies was reported over a 15-year period by Gayler and coworkers on aluminum-copper.l,2,3,4 Working with silver-rich copper alloy, Cohen5 secured some very interesting Rockwell F hardness changes of from 1-5 Rockwell points between the first peak and valley. Fink and Smith borrowed one of Cohen's specimens and, following his heat treatment and quenching practice to the letter, secured6 very different results in which only one peak was obtained and in which the hardness level at the aging lime of Cohen's first peak was 20 Rockwell F points higher. Fink and Van Horn7 encountered serious deviations in age-hardening high purity aluminum-zinc alloys. They stated that "the discrepancies were larger than might be expected from possible experimental errors in the Brinell readings." Geisler, Barrett and Mehl8 likewise encountered anomalous hardening results in aluminum-silver alloys, securing quite different age-hardening curves from two identical specimens. They stated that "the treatments of these samples had been the same, so that the different behaviors could be attributed only to accidental variations in the quenching practice."

Jan 1, 1950

By G. R. Hodgson, M. P. Lebourg

The introduction in the field of a new type well completion called for the setting of tubing open-ended in the well before perforating the casing. This paper describes a new perforating tool of the shaped charge expendable type, small enough to pass through tubing and powerful enough to perforate the casing. The perforations are produced at an angle and are large enough for optimum production. Performance of this tool in targets and under various well conditions is described. Very often no lifting equipment will be available at the well. In some cases, pressure will exist in the well at the time of the perforating operation (workover wells or multiple trip perforation) ; therefore, new equipment and new technique for the perforating operation were devised. This paper describes this equipment and technique, particularly casing collar recording, sheave support, and cable pull-down device. this last item being necessary for wells under pressure. Results obtained with this tool in the field are given. INTRODUCTION One of the key requirements for the introduction in the field of a new method of permanent well completion was the development of a new perforating method involving the use of a perforating gun small enough to go through tubing and with enough penetrating power to perforate the casing satisfactorily. The equipment described in this paper was basically designed to go through open-ended two-in. tubing and to perforate 5 1/2 in. casing. The equipment is illustrated in accompanying figures. NEW COMPLETION METHOD With the new permanent type well completion, the production string of casing is run and cemented through the potential producing zone. Open-ended tubing is -then run into the well and used to replace the drilling fluid with oil or water. The amount of the oil or water "cushion" can be varied according to the expected bottom hole pressure. Thus, if desired, the hydrostatic head can be greater, equal to, or less than the expected pressure within the zone to be perforated. Mud having been displaced, the tubing is -then positioned so that the end is above the zone to be perforated. The Christmas tree and flow lines are installed and tested. The drilling rig can now be removed from the well since it is not necessary for the perforating operation, thus resulting in a saving in rig tme. The perforating equipment is then moved to the well and the gun lowered through the tubing. After the gun passes out of the open end of the tubing, the depth measurements are correlated with casing collars and the gun placed opposite the zone to be perforated. Upon firing, the gun body is shattered and falls to the bottom of the well. Since the lubricator has been closed before firing, it is possible to withdraw the casing collar locator and head and then open the well immediately to the tanks. DESCRIPTION OF GUN An investigation of two basic types of Perforators, namely a bullet perforator and a shaped charge gun, was undertaken towards the development of a gun to meet the aforementioned requirements. Preliminary tests on various bullet perforator designs within the diameter limitations did not give results encouraging enough to warrant further study. Somewhat better results were obtained by using conventional shaped charges; but, as in the case of the bullet types, the necessarily small overall diameter proved to be a severe limitation and resulted in insufficient penetration. A shaped charge employing a new design was developed which gave excellent penetration. These shaped charges were designed to produce a large hole directed upward at a 45" angle. In order to obtain the maximum space possible for these charges, it was decided to use an expendable carrier made of drillable material, usually aluminum, which would shatter at the time of firing, leaving only harmless fragments at the bottom of the hole. The fixed spacing is five shots per ft. wit11

Jan 1, 1952