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By B. Bryan

The tank car price of gasoline today is controlled by oil in the ground, rather than by stocks of gasoline or methods of refining. Previous to the commercial cracking of fuel oil, there was a normal and continuous relation between gasoline stocks, consumption and prices. From the beginning of the new cracking era in 1923 to the summer of 1926 there was a changing relationship, growing toward a correlation between the potential gasoline in storage and the price of gasoline. Since the development of large reserves of shutin production in Wyoming, California, Seminole, West Texas and Venezuela, the relationship between stocks of gasoline and gasoline prices has disappeared. The extreme depression of the Group 3 price can only be accounted for by oil which is not being produced but which we fear may be produced at any time. In Fig. 1, the curve of gasoline stocks is simply stocks of finished gasoline. The curve of potential gasoline is made by taking 40 per cent. of all stocks except gasoline, kerosene and lubricants, adding to that stocks of finished gasoline and dividing the sum by total gasoline con-sumption to get the months' supply of gasoline at the current rate of consumption. The price curve is the lower figure given by the National Petroleum News for the first quoted date of each month, with the price scale reversed. Stocks of potential gasoline have decrrased from 17 months' supply at the peak of 1924 to a low of 7 months' supply during the past summer, yet the low immediately precedes the lowest price for gasoline since it was a waste product. The tendency of the price curve to parallel the curve of potential supply is quite pronounced until the summer of 1926, since which time they have abruptly separated. The curve of gasolinct stocks is equally remarkable in relation to price when it is considered that total consumption for the year 1927 is almost exactly twice that of 1924. Clearly a new factor has been introduced. There is no possible factor to account for this distortion except known reserves of oil in ground storage, and therefore, until such time as the Bureau of Mines or the

Jan 1, 1928

By S. C. Libby

Physical degradation of calcined bauxite is related to the presence of goethite in the raw bauxite and to the development of secondary gibbsite. Goethite in the bauxite matrix will shrink and decrepitate during calcining, leaving a friable matrix and allowing disaggregation of the calcined bauxite during transport and handling. A matrix consisting of cryptocrystalline gibbsite alone or mixed with hematite will not shrink during calcination, yielding a calcine with high abrasion resistance. The development of secondary gibbsite between coarse gibbsite crystals also reduces degradation of the calcine by reducing the amount of disruption between grains resulting from differential thermal expansion.

Jan 1, 1981

By Robert L. Schuster, James A. Doolittle, Ronald L. Sack

The effect of the height of a retaining-wall-supported berm on the slope stability of an idealized mine-tailings dam was investigated. The material in the dam was idealized as a two-layered system with the phreatic surface delineating the boundary between the layers. In each layer the tailings were assumed to be homogeneous and isotropic. The effect of variation in height of the berm was examined for tailings dams with three different, commonly occurring slopes. The stresses and displacements were obtained using the finite element method. An incremental analysis technique was employed to simulate sequential construction of both the tailings dam and the retaining-wall-supported berm. A one-dimensional element was used to represent all interfaces and discontinuities in the finite element model. Assuming a hyperbolic model, the nonlinear stress-strain relationship for the tailings was approximated using the method of successive increments. The stresses obtained in the finite element analyses were used in conventional slope stability analyses assuming circular failure surfaces. The results of the study show that the use of a retaining-wall-supported berm is an effective means of improving the stability of a tailings dam. This increased stability is greater for dams with steeper slopes. In addition, the increase in factor of safety is particularly notable for berm heights less than 25% of the height of the dam.

Jan 1, 1975

By Valentin R. Garfias, C. O. Isakson

The production of oil in Mexico during 1929 was approximately 45,000,000 bbl., or 5,000,000 bbl. less than in 1928. The production of the fields near Tampico showed a decline of over 10,000,000 bbl. for both the light and heavy crudes, which was partly offset by an increase of over 5,000,000 bbl. in the production of the fields in the Isthmus of Tehuantepec. During 1929 the retrenchment policy followed by practically all the companies was continued and no material improvement should be expected until the unsatisfactory conditions that brought about this situation are remedied. A new administration has just assumed control in Mexico; it should remain in power for 6 years, and the progress of the oil industry during that time will depend primarily on the policy pursued by the new government with respect to oil development. Development During 1929, there were drilled 214 wells as compared with 371 in 1928 and 583 in 1927. The percentage of producers in 1929 was 47.2 as against 34 per cent. in 1928. The new wells did not show water as quickly as in 1928, particularly in the Cacalilao field, where the greatest number of producers was brought in, their average initial daily production being 380 bbl. The flush daily production per well in the Southern fields was 1730 bbl., while the wells in the Isthmus of Tehuantepec came in with an average of 770 bbl. Development is summarized in Table 1. In the Southern fields 63 wells were drilled in 1929, of which 23 were producers, the best being drilled in Paso Real. This development tends to show that the southern extension of Dos Bocas-Alamo fault from Alamo to San Isidro terminates at San Isidro. The two wildcat wells completed in 1929, one in Magiscatzin and the other in Xicotencatl, were failures, and at the end of the year there were eight wildcat wells drilling and material was being hauled for two more.

Jan 1, 1930

By R. Hogg

The mathematical description of solids transport in mills is an important aspect of the development of comprehensive models for the analysis, simulation and control of grinding systems. The basic mechanisms of particle transport and mixing, including gravity flow, carrier fluid transport, and "diffusion", are reviewed and their relative importance in wet and dry ball mills is discussed. Specific models for transport and mixing in dry, grate-discharge and wet, overflow ball mills are described. The limitations of the models, parameter estimation problems, scale-up criteria etc. are discussed and the conditions which lead to particle size dependent transport, and hence to internal classification in the mill, are described in detail.

Jan 1, 1984

By J. Moore Samuel

INTRODUCTORY BEFORE the year 1909, no measurements of dust losses and flue gases had been made at the Copper Queen Reduction Works, at Douglas, Ariz. At that time the "unaccounted" loss of the smelter had reached a figure, that drew attention to the possibility of large stack losses. The measurement of dust losses had not been studied much at that time, and estimates of dust losses, with a few exceptions, were the results of tests by what has been termed "chemical methods," that is, the aspiration and filtration through cotton, wool or some similar medium of a few liters of gas, the dust being weighed on a chemical balance, and the volume of gas computed from the volume of aspirator water. The possible error of this method is enormous, and the probable error much too large for reliable results. Since the object of these tests was to discover not only the extent of the dust losses, but also the possibility of profitably reducing the same, it was decided that the method adopted must have the following characteristics: 1. The sample of gas taken for filtration must be representative of the whole volume of gas, that is to say, it must have the same dust content. This condition will be fulfilled in all cases if the gas sample is drawn off without change of rate of flow. Then it will contain the same proportion of entrained or suspended particles of dust as the original gas. In the case of flue gases which contain only fume, at a temperature above or near the sublimation point, this condition need not be adhered to since the fume will not behave as entrained particles, but more nearly as a true gas. Consequently the gas sample in this case only may be drawn off at any rate of flow. 2. The gas sample taken must be large enough (a) to yield sufficient dust to permit of accurate chemical and physical examination; (b) so that the ratio of the total volume of gas passing through the flue to the volume of gas sample taken shall not be too large.

Jan 6, 1916

By E. Alan Haley

Accurate and economic control of line and grade on long tunnels, large structures, excavations and waterways has been a problem to surveyors and engineers for decades. The conventional method of surveying, incorporating a level, transit and a number of surveying technicians, has proven to be a very expensive and time-consuming operation. Now, however, engineers have adapted the laser to help ease the problems of surveying, at the same time increasing the efficiency of such operations. The laser, which projects a continuous, narrow red beam of brilliant light, provides a constant alignment reference that does not interfere with personnel or equipment. A complete laser alignment system, specifically designed for and suited to a variety of mining and tunneling operations, has been developed by the Perkin-Elmer Corp. The engineering significance of this development can be fully realized when it is noted that, aside from potentially tremendous economic advantages in terms of labor savings, the laser beam provides a system of alignment that is at least ten times more accurate than presently used optical systems. The new laser system provides accuracies within 10 microinches per foot (1 x 10-5in.) when used with an accessory centering detector. In one of its first field trials, the laser was used for alignment of a two-mile tunnel which showed a total deviation of less than 5/8 in.

Jan 4, 1968

By R. F. Hewlett

All ore reserve estimates are based on some system for assigning an area of influence to each drill hole. Commonly used methods of calculation are the polygonal, triangular, statistical analysis, and cross-sectional. Each of these methods is based on different volumetric considerations and the weighting of grade with tonnage varies with each method. Because the characteristics of each mineral deposit are different, a preliminary survey of these characteristics should be made for each individual deposit to determine which method or methods should be used. In this project the several methods were not only compared with one another, but also against actual production records. Basic data was derived from a mined out portion of the Silver Bell pit near Tucson, Ariz. All calculation was carried out on a digital computer, and the first step was development of computer programs which would yield the desired information. The second step was the coding of input data into punched card form. Cost and speed of computer operation were measured, and these results are given with the computer program summaries on page 38.

Jan 1, 1961

By S. Norton, S. LeFevre

In the West, capitalists have expended many millions of dollars developing the low-grade porphyry ores of copper. Half a dozen of these great enterprises have proved to be wonderful commercial successes. They have demanded improved crushing and concentrating machinery and consequently it has been developed. Many improved methods, cheap power, superior business organization, all these have contributed to this success, but the main feature is the handling of the material in enormous quantities, on a manufacturing scale. The mining chance of "striking it rich" has been eliminated by the manufacturing certainty of handling large quantities of material of known value, which while of relatively low grade, is available in large tonnages, assuring a supply for many years' run of the mill. Then the returns on the money invested are sure. The concentration of low-grade magnetic iron ores, separating the magnetite crystals from the gangue by the use of magnets, is a field of work in which the lessons taught by the development of the porphyry coppers can be studied to advantage. Large-scale operations, and the liberal expenditure of enough money at the start to insure the most economical operations, are the means of securing the desired results. The problem is to utilize millions of tons, and we may safely say billions of tons, of now worthless iron-bearing rock and to produce from it 10,000,000 to 20,000,000 tons per year of high-grade ore carrying 60 per cent. iron or higher; to take the lean material as found in nature, varying widely in iron content, and bring it up to a uniform standard of shipping ore. At present these ores are mined carrying from 25 to 50 per cent, iron, and the shipping product is brought up to 60 or 65 per cent. Fe. If future economies of operation make it possible to extend this process so that 15 per cent. iron in the crude ore can be treated as a commercial success, the additional tonnage available will be enormous. A 15 per cent. Fe crude ore raised to 60 per cent. Fe concentrate with 5 per cent.

Jan 1, 1917

By G. W. Jarman

THE purpose of this paper is to present briefly a description of some of the special methods of separation or concentration, either singly or in combination with others, and to give certain operating data and examples. Explanation of the usual methods of large-production mill treatment, such as flotation or wet tabling, or of chemically treating industrial minerals, is not included in the scope of this paper, although one of these methods might be, in certain instances, augmented by one or more of the special methods that will be enumerated herein. Description of these special methods will be centered on magnetic separators, electro- static separators and air flotation or air tables. MAGNETIC SEPERATORS In general, separating is achieved by exerting upon a particle some kind of force opposed to gravity, either directly or at an angle. For example, in the Wetherill or cross-belt type of magnetic separator some particles are lifted vertically from the others because they have been exposed to a force to which they respond more readily than particles of lesser magnetic susceptibility. Of course, there is a limitation to this vertical rise, for the particle must be of a high enough susceptibility to receive a magnetic force greater than the 980 dynes per gram of gravitational urge. To overcome this limitation, the induction type of magnetic separator was developed, so that it is only necessary to instill, say, 30 to 60 dynes per gram instead of the 980, to cause a deflection away from the vertical in falling, and that deflection can be used advantageously when falling by inserting a dividing knife-edge. The induction magnetic separator (Fig. 1) has become a fairly well known method of concentrating and purifying. For example, abrasive grain was among the materials that did not respond to the previously best known type of magnetic separator, such as the Wetherill type, and the development of the induction magnetic separator in the plant of a

Jan 1, 1938

By R. P. Carreker, J. G. Leschen, J. H. Hollomon

The external appearance of a crystal which has undergone plastic flow suggests that adjacent blocks of the crystal have glided bodily past one another along the slip planes. However, the great discrepancy between the shear stresses calculated to effect such a movement and those actually observed has for many years stimulated searches for more satisfactory interpretations of the slip process. Appreciable success in these efforts has been realized by assuming the presence in the crystal of various sorts of imperfections and by considering the consequences of the presence of these flaws when stress is externally applied. The theory that has received the most attention recently—that of dislocations—postulates the occurrence of small, mobile imperfections or dislocations which move through the crystal along the slip direction, each dislocation being attended by a local shear displacement of one interatomic distance. Thus only that portion of the crystal through which the dislocation has passed may be said to have slipped. Since each dislocation produces a displacement of only one interatomic distance, an avalanche or train of many dislocations would be necessary to account for the observed displacements of several hundred or thousand interatomic distances. The salient point of the theory of dislocations is the concept that a slip band does not suddenly appear in its entirety. On the contrary, it grows progressively across the slip plane as the individual dislocations successively appear and advance in a train through the crystal. However, the concept of growth is not intrinsic only to the theory of dislocations, since atomistic mechanisms other than that postulated by the dislocation theory can quite probably also describe the growth of a slip band. For instance, a slip band might resemble a disc-like interface that appeared and then grew continuously from a small size, producing a displacement that increased with the size of the disc. Whatever the precise mechanism, the concept of growth is in itself consistent both with the observed low values of critical shear stress and with the experimental observation that slip bands frequently do not traverse the entire crystal. The likelihood that slip bands grow implies that they must first be nucleated and that the initiation of slip can therefore be analyzed in terms of the general concepts of nucleation. Indeed, this suggestion was advanced1 several years ago, but the matter does not appear to have been further pursued. Recent advances in the theory of nucleation 2,3,4 have encouraged such a treatment of the slip process. As will presently be demonstrated, this approach to the problem not only accounts successfully for the incubation periods that have been observed 5,6 to precede slip but also predicts certain transient effects in the deformation process. The existence of these transients apparently has not hitherto

Jan 1, 1949

By G. W. Land, A. F. Duzy

There have been some problems associated with hot coal, defined as oxidizing coal heating toward ignition temperature, in shipments from the US to overseas markets. This paper will provide, first, a brief review, together with a selective bibliography. Second, a thorough discussion of coal oxidation is covered. Third, potential effects of storage are presented and, lastly, methods are suggested for the safe storage and bulk transfer of coal. The scope includes coal storage for power plants.

Jan 1, 1986

By J. Amanat, H. J. Siriwardane

A numerical procedure based on nonlinear finite element analysis has been developed for predicting subsidence profile over longwall mine panels. The developed procedure has been verified by comparing predictions with published field observations at several mine panels. This paper presents certain aspects of predicting subsidence profile over mine panels located in hilly terrain. Analysis of four such cases are presented herein.

Jan 1, 1984

By E. H. Lovitt, A. C. Skerl

After nine years of continuous operation it is a good idea to take stock of the geological concepts that guide the working of a mine. This is a welcome opportunity to discuss the Lovitt gold mine, which has been a challenge in both the geological and operational fields. The occurrence belongs to the extensive group of epithermal gold-silver deposits once worked so vigorously in the western states, Hungary, and New Zealand and still producing in Central America and the Philippines. These deposits are characterized by a relatively shallow vertical range up to 2000 ft, and often much less, and by bonanza orebodies of even more limited range. The area in which they occur is frequently widespread, so that exploration must be directed along and across the strike of known favorable structures in search of repetitions.

Jan 9, 1958

By W. N. Logan

A survey of geological conditions, production and prices in Indiana oil fields. Shows no production and indefinite prospects from the sub-Trenton formation; good production and much untested territory in Trenton formation; and fair production from the Pennsylvanian with fair prospects for the future in both the Pennsylvanian and Mississip-pian formations. THE petroleum industry of Indiana made somewhat notable progress during the year 1923, considering the number of handicaps it encountered. The price of labor and materials continued to have an upward slant while the price of crude oil took a decidedly downward course. In spite of these adverse conditions, the quantity production will closely approximate that of 1922, when it passed the million-barrel mark. The progress of the industry in Indiana should be considered fairly satisfactory as long as the present production is maintained. In other words, if the loss of production from the waning old wells can be offset by the production from the new for a period of 10 or 15 years longer, the industry may have cause for congratulation.

Jan 3, 1924

By E. W. Davis

Iron-ORE beneficiation methods are determined largely by blastfurnace requirements. There are still many millions of tons of direct furnace ore in the Lake Superior district and blast furnaces are designed and operated for the most efficient use of this material. Beneficiated ore must be so prepared that existing furnaces may use it without alteration in design or radical changes in practice. Many attempts have been made to develop new furnaces or processes for smelting iron-ore concentrate not suitable for blast-furnace use, but these processes have gained little importance. It is, therefore, the endeavor in beneficiating iron ore to make a product that will give at least as good results as direct furnace ore in existing blast furnaces. The term "beneficiation," as applied to iron ore, does not necessarily mean concentration, but more accurately means "dressing up" the ore so that it is more acceptable to the blastfurnace operators. In modern blast-furnace practice the structure of the ore is quite as important as the chemical analysis. Certainly, the higher the iron content and the lower the silica, phosphorus and sulfur, the more desirable the ore bccomcs; but if the structure is bad, that is, if the blast-furnace gases can penetrate the charge only with difficulty, the ore is undesirable regardless of its analysis. This means that the ore should be as uniform in size as possible and free from fines, and also that the individual particles of ore should be pervious to the reducing gases of the furnace. Structure and purity are the primary requirements for a furnace ore and structure is just as important as purity. Iron-ore beneficiation processes can be divided, therefore, roughly into two main classifications: (1) processes that primarily improve the structure, and (2) processes that primarily improve the chemical analysis. During the past 10 years approximately 25 per cent of the ore shipped from the Lake Superior district has been beneficiated. Of this about half has been crushed and screened, a simple operation that primarily improves the structure but in some cases also improves the analysis slightly. The other half of the shipment of beneficiated ore, amounting to an average

Jan 1, 1935

By M. B. Yung

The Fu Chuan district lies near the eastern boundary of Kwang Si province in Southern China and is connected with the coast by the West river and its branches.

Jan 1, 1915

By Samuel S. Wyer

The installation of the gas-producer power-plant in America has been so unusual that all engineers have viewed it with interest; a large majority, however, regard it with a lack of confidence and many with positive distrust. Despite the fact that

Jan 1, 1906

By Subhas G. Malghan

The response of feldspar flotation to tallow diamine dioleate collector in the presence of sulfuric acid is studied using batch flotation experiments. Application of this nonhydrofluoric acid (non-HF) reagent system in the flotation of mineralogically and chemically different feldspar ores is compared with that of the conventional hydrofluoric acid system. The dependence of flotation recovery and concentrate grade on feed particle size distribution, conditioning time, pulp density, and pH, combined variation of collector and acid addition rates, sodium hydroxide concentration in the collector solution, and initial pulp pH Prior to conditioning is studied. The results have been discussed in relation to applicability of the non-HF system to plant trials, and the nature of the collector adsorption in the selective flotation of feldspar.

Jan 1, 1982

By Louis Ware

At the beginning of the present war, the United States faced the need to multiply its production of magnesium metal almost roo times within the shortest possible period. Urgently needed for construction of military aircraft, incendiary bombs, and other war uses, magnesium was at the top of the list of critical war materials. Up to that time only one Producer, employing Only One process and using One raw material in a single plant, represented this country's entire Production capacity. It was immediately desirable to plan a numher of plants located strategically over the Count'Y and to expand an industry more rapidly and to a greater extent than ever before had been attempted in so short a time. In '939 this American producer, the Dow Chemical .9 was making about 7 million Pounds of magnesium metal. It utilized as a raw material brine containing magnesium chloride, which was pumped from wells in Michigan. The logical ap-preach to certain increased production was to employ the same process on the same raw material in other sections of the United States. In Europe and other countries, different processes had been used and different raw materials were being utilized, but all of the skill and knowledge for production in this country was that of using the Dow type of cell and magnesium chloride as a raw material. The Government was testing other processes, but none then had been proved commercially feasible. Development OF New Process The International Minerals and Chemical Corporation had available a large quantity of magnesium ,chloride at Carls-bad, New Mexico, contained in the end liquor produced from its potash plant sillce the buildng of the plant in 1941 It was the only company mining commercially a magnesium ore and having anything like this quantity of magnesium chloride liquor. The magnesium ore, langbeinite, was being mined from the 800-ft. level for its content of potassium sulphate. This ore, a potassium magnesium sulphate, was reacted in a base exchange plant with potassium chloride to produce potassium sulphate, the discharge liquor having a high content of magnesium chloride. Three potash-producing companies are in the Carlsbad area, but only International has developed and is commercially producing the potash-magnesium ores. The lower, or No. 4, veil, in that area is potassium chloride ore, and is continuous through all the properties. The langbeinite, or No. 2, vein is minable at the International property, but occurs sparsely, if - at in other areas being mined in that vicinity. It is understood that most of the mag. nesium produced] by Germany comes from magnesium and magnesium-potassium ores obtained from potash mines. It was logical for International to pro-pose to make available this magnesium material and to offer its technical staff to design, construct and manage a magnesium plant for the account of the Government. The plan that finally was adopted by the

Jan 1, 1944