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By J. Morgan Clements

PETROLEUM has been known in Japan since at least 668 A. D., for a picture shows the presentation, during that year, to the Emperor Tenchi (Tenji) of "burning water" and." burning earth" by his subjects from Echigo Province, which today is the largest producer of petroleum in Japan. The burning water was doubtless petroleum and the burning earth either bituminous shale or oil-soaked earth or rock from near the oil seepages. The early methods of getting the oil were simple and similar to methods used today in Japan and in China. Where the seepages occurred, trenches or shallow wells were dug along the seepages and allowed to fill with oil which was then bailed out; in some cases, they filled with oil and water and overflowed. During the 300 years following 1500 A. D:, the use of petroleum in Echigo Province seems to have increased considerably, as compared with earlier centuries, and records show that in 1818 the depth of the wells had been greatly increased. Doubtless, they passed through the seepages and tapped the shallow oil-bearing strata; probably some of these deeper wells were dug before that time. The real value of petroleum was not recognized until early in the Meiji era, which began in 1868, when the Japanese learned that the kerosene that was being imported was derived from petroleum. Guided solely by information obtained from books, they refined the oil and increased the depth of their wells in order to increase the production. The deepest well, dug by hand, about this time was 894 ft.1 (273 m.) and by 1874 the recorded production reached 3499 barrels. In 1876, Benjamin Smith Lyman prepared geological maps of the Echigo oil field, which were the first. of such geological maps made in Japan, and based on these a more enlightened development of the oil fields began; the. Japanese, however, still dug the wells by hand. Toward the end of the '80s, an American well-drilling outfit was secured, but the efforts to use it failed from lack of experience by the operators. In 1888, a complete well-drilling outfit was, purchased and American oil-well

Jan 7, 1922

By Edmund C. Pechin

I REGRET that I am unable to present this subject in definite form and detail. All I shall attempt at this meeting is to lay before you some curious facts, the bearings and explanations of which must be reserved for future consideration. I hope before the next meeting to have carried experiments far enough to furnish a more important contribution to the science of iron metallurgy. The Wickersham process consists in the introduction into the molten metal, as it runs from the furnace, of air from the hot blast. Mr. Samuel Wickersham is the originator of the plan, as applied in practice, although Mr. Martien had the idea a long time ago, and, I believe, .went to England about it. But at that time Mr. Bessemer was coming before the public with his invention, which engrossed the attention of iron-masters, and Mr. Martien accomplished nothing. The principal difficulty in our experiments at Dunbar was to get a practicable runner or trough, through which the molten metal should pass, and in which it should be exposed to the action of the blast. The runner we used was ten feet long, and perforated on the sides to permit the entrance of the air-currents. When we used a cast-iron and fire-clay runner, the heat was so great that before we were more than half done with a run, the lower part of the runner was melted, and we had a magnificent Fourth of July display of fireworks until the blast was shut off. We had to abandon fire clay. The runner with which we have had the best success ,is made of wrought-iron tubes, 2 1/2 inches in diameter, attached to a wrought-iron frame, and lined with a mixture of crushed conglomerate (quartz) and a little fire clay to give it cohesion. The wrought-iron shell curves inward over the upper edges, so as to catch and throw back into the current the flying sparks and particles of metal thrown out by ebullition. With this we have been able to run 12 to 14 tons at a heat with great ease. Mr. Wickersham has since prepared this material (pounded quartz) into a shaped brick or tile, with the necessary perforations for the passage of the air, which promises to answer every requirement for steady working. As regards the improvement in the quality of the iron, there seems to be no question. A large number of practical tests were made in

Jan 1, 1873

By F. M. Lewis, J. F. Myers

W. I. Garms-—The authors state that when they added 11 tons of balls to the 45 pct volume ball load, the power needle did not budge. The question arises as to whether any increase in capacity accompanied the 11-ton addition. It is hardly conceivable that all of the balls making up the 11-ton addition were sterile. However, as the work done in the ball mill is not by kilo-watthours per se or balls per se but by kilowatthour-balls, it is possible that the kilowatthourballs in the mill before the 11-ton addition had a different amperage, voltage or robustage than those in the mill after the addition and that the overall outcome was that equal work was done before and after the addition. The authors can keep the efficiency that they got with the 45 pct volume 1-in. ball charge and get additional capacity by putting more kilowatthourballs to work in the form of the addition of 11 tons of 2-in. balls to the present ball charge, and subsequent makeup additions by weight of 20 pct 2-in. balls and 80 pct 1-in. balls. J. F. Myers (authors' reply)-—Mr. Garms points his finger at the 11 tons of "sterile" balls added to the Tri-cone mill. A fact so interesting to us that we felt it should be reported. Clearly, ball slippage at the existing mill speed prevented any further transfer of power from the shell to the ball mass. We agree that the kilowatthourballs would increase, were we charging rough 2-in. balls as suggested by Mr. Garms. The assumption is, of course, that we would get a corresponding increase in work done. Our reported data (CIME meeting, Vancouver, 1946) shows a gain of work accomplished of 7.6 pct as we decreased the ball size from 2 in. to 11/2 in. and a further gain of work accomplished of 2.1 pct when we went from 11/2 in. to 1 in. The small ball results reported by H. R. Banks at Chapman Camp are also very convincing. In the case of 2-in. balls they would take the conventional ball path and start cascading. They would thus destroy the classifying pool over the "foot" of the

Jan 1, 1951

By J. F. Myers, F. M. Lewis

W. I. Garms-—The authors state that when they added 11 tons of balls to the 45 pct volume ball load, the power needle did not budge. The question arises as to whether any increase in capacity accompanied the 11-ton addition. It is hardly conceivable that all of the balls making up the 11-ton addition were sterile. However, as the work done in the ball mill is not by kilo-watthours per se or balls per se but by kilowatthour-balls, it is possible that the kilowatthourballs in the mill before the 11-ton addition had a different amperage, voltage or robustage than those in the mill after the addition and that the overall outcome was that equal work was done before and after the addition. The authors can keep the efficiency that they got with the 45 pct volume 1-in. ball charge and get additional capacity by putting more kilowatthourballs to work in the form of the addition of 11 tons of 2-in. balls to the present ball charge, and subsequent makeup additions by weight of 20 pct 2-in. balls and 80 pct 1-in. balls. J. F. Myers (authors' reply)-—Mr. Garms points his finger at the 11 tons of "sterile" balls added to the Tri-cone mill. A fact so interesting to us that we felt it should be reported. Clearly, ball slippage at the existing mill speed prevented any further transfer of power from the shell to the ball mass. We agree that the kilowatthourballs would increase, were we charging rough 2-in. balls as suggested by Mr. Garms. The assumption is, of course, that we would get a corresponding increase in work done. Our reported data (CIME meeting, Vancouver, 1946) shows a gain of work accomplished of 7.6 pct as we decreased the ball size from 2 in. to 11/2 in. and a further gain of work accomplished of 2.1 pct when we went from 11/2 in. to 1 in. The small ball results reported by H. R. Banks at Chapman Camp are also very convincing. In the case of 2-in. balls they would take the conventional ball path and start cascading. They would thus destroy the classifying pool over the "foot" of the

Jan 1, 1951

By D. L. Blakeman, Trimble. J. W., S. W. Banning

Noranda's Grey Eagle mine and mill, in the Siskiyou Mountains of northern California, began shakedown operations in the late fall and early winter of 1982. This paper describes some of the unique features in mineralogy, milling, and water treatment operation at Grey Eagle. In addition, major start-up problems in the mill and water treatment plant are discussed along with measures taken to correct these problems.

Jan 1, 1986

By Arthur Clark, Terrill

THE Tri-State field is now believed to be the largest zinc district in the world. It has a potential production sufficient to supply the entire zinc demands of the country. It is estimated that a train 70 miles long would be required to haul the district's 1919 output of 60 per cent. zinc concentrates. For many years,, including 1917, Missouri surpassed Oklahoma in zinc production. In 1918, however, Oklahoma led by a wide margin and, in 1919, Missouri produced less than one-sixth of the total for the three states, when Kansas replaced Missouri in second place in the production. The district is now producing one-third of the zinc of the world and twice as much as ever before at the present price.

Jan 1, 1920

By R. W. Gurry

IN the course of a series of measurements of the rate of diffusion of carbon in austenite at about 960°C. (1760°F.) and 1110°C. (2030°F.), it became necessary to determine carbon concentration when austenite is saturated with graphite, because of indications that the hitherto accepted value of the solubility of graphite in this temperature range is too low. Specimens of carbonyl iron were saturated at temperature in a hydrogen-toluene atmosphere which was in equilibrium with graphite. The carbon content of the steel was measured either by combustion or by the loss of weight after substantially complete decarburization in an atmosphere of hydrogen saturated at room temperature with water vapor. The absence of carbide or graphite as a phase at temperature was demonstrated by microscopic examination of saturated specimens that had been drastically quenched. The mean result of concordant measurements is that gamma iron saturated with respect to graphite contains 1.39 per cent carbon at 957°C. (1755°F.) and 1.89 per cent at 1110°C. (2030°F.). These two values, plotted along with what appears from the literature to be the best value (0.69 per cent) at the iron-graphite eutectoid temperature (738°C. or 1360°F.), yield a curve that is almost linear, and which, continued upward through a short interval, leads to a limiting solubility of 1.98 per cent at the iron-graphite eutectic temperature 1135°C. (2075°F.) instead of the commonly accepted value of about 1.7 per cent. EXPERIMENTAL PROCEDURE The samples of carbonyl iron, with the exception of those for microscopic examination, were cylinders 3.8 cm. long, 0.475 cm. in diameter. They were placed in a graphite holder and suspended in a vertical furnace, the temperature of which was controlled precisely by means of the resistance of the platinum winding.1 In the empty furnace the range of temperature over a distance of 4 cm. at the heat center was 9°C. (16°F.) but at a given location the temperature remained within ±0.5°C. (0.9°F.); it was measured by inserting a platinum-rhodium couple calibrated at the melting point of palladium, 1555°C. Since the presence of the sample probably improved the uniformity of temperature, it was decided to consider the average temperature of the sample to be 3°C. lower than the maximum measured in the empty furnace with the same setting of the controller. Data were obtained in the vicinity of two temperatures, 960°C. (1760°F.) and 1110°C. (2030°F.). The samples for microscopic examination, 2.2 cm. long, 0.475 cm. in diameter, were suspended individually on pure iron wire; for these no temperature correction was applied. The carburizing gas passed into the furnace was dry, oxygen-free hydrogen saturated at room temperature with

Jan 1, 1942

By R. S. Busk, R. F. Marande

The magnesium-aluminum-zinc 'system contains most of the magnesium-base alloys used commercially, although in practice the ternary alloys are usually modified by the addition of a small amount of manganese. Table I contains the magnesium-base commercial sand-casting alloys most widely used throughout the world, together with their typical tensile properties. These alloys may be regarded as a single family of varying aluminum and zinc content, disregarding manganese. A concise means of presenting data for them is by means of iso-property lines plotted on triangular coordinate paper. Constitutional, casting, and mechanical properties are presented in this manner. The data are given with the obiect of providing reference material, and to aid in the choice of a commercial alloy to serve a particular purpose. Detailed, critical analysis of the commercial alloys has been covered in a previous paper.' All alloys reported were made in rj-lb. melts, superheated to r700°F. for 15 min., cooled to r400°F. and poured in sand molds. The test bars produced had a 1/2-in. reduced section and were about 6 in. long. Except for the data represented in Figs. I and 3 the alloys used were of commercial purity and contained 0.1 to 0.2 per cent Mn in addition to the aluminum and zinc. Constitutional Data Under the heading of Constitutional Data are included all known data on con-

Jan 1, 1946

By R. F. Marande, R. S. Busk

The magnesium-aluminum-zinc 'system contains most of the magnesium-base alloys used commercially, although in practice the ternary alloys are usually modified by the addition of a small amount of manganese. Table I contains the magnesium-base commercial sand-casting alloys most widely used throughout the world, together with their typical tensile properties. These alloys may be regarded as a single family of varying aluminum and zinc content, disregarding manganese. A concise means of presenting data for them is by means of iso-property lines plotted on triangular coordinate paper. Constitutional, casting, and mechanical properties are presented in this manner. The data are given with the obiect of providing reference material, and to aid in the choice of a commercial alloy to serve a particular purpose. Detailed, critical analysis of the commercial alloys has been covered in a previous paper.' All alloys reported were made in rj-lb. melts, superheated to r700°F. for 15 min., cooled to r400°F. and poured in sand molds. The test bars produced had a 1/2-in. reduced section and were about 6 in. long. Except for the data represented in Figs. I and 3 the alloys used were of commercial purity and contained 0.1 to 0.2 per cent Mn in addition to the aluminum and zinc. Constitutional Data Under the heading of Constitutional Data are included all known data on con-

Jan 1, 1946

By G. B. Kasik, George Sachs, George Espey

IT has been reported frequently that the hardness and strength vary over the cross section of cold-worked, particularly cold-drawn, material. Brass rod and wire usually has been found to possess a maximum strength and hardness near the surface.1,2 According to Sachs,1 the center fiber has about the same strength as a wire stretched by the same amount in a tensile-test machine, the strength increasing toward the surface (Fig. I). These differences are particularly large for wire given a small reduction on drawing through a die with a wide opening. However, with increasing reduction and hardness, a tendency to form a thin soft surface skin becomes apparent. On the contrary, copper wire has usually been found to possess a soft surface skin" and it has been reported by Harris3 that during the cold-drawing of hot-rolled wire the surface layer becomes increasingly softer than the core, while the layer of maximum strength moves toward the core, it being found near the surface at first. The increase of strength and hardness from the core to the skin is readily explained by the observation that, in addition to the stretching, the layers of a rod or wire are sheared more the closer they are to the surface.1,6-8 However, the presence of a soft surface layer can be attributed only to an annealing effect. The source of such a softening might be the extremely high temperature that originates from the friction between [ ]

Jan 1, 1941

By J. O. Brittain, E. P. Lautenschlager, D. A. Kiewit

Compression tests were run in the temperature range of 700° to 900°C ox 0' phase NiAl intermetal-lic alloys of several grain sizes. At these temperatures the minimum strengths were observed at the stoichiometric composition. While significant increases in strength occurved in both the low-nickel (vacancy) and high-nickel (substitutional) regions, the highest strengths were found in the high-nickel region. During deformation serrated flow was sometimes observed in the low-nickel alloys. After deformation transgranular cvacking and deformation striations were observed in all compositions tested. AS part of a general investigation of the properties of NiAl inter metallic compounds, a preliminary study of the role of point defects upon plasticity was made by high-temperature compression tests on ß' NiAl specimens of several grain sizes and compositions. ß' NiAl is an intermetallic compound having a CsCl structure and a rather wide range of composition from A1-45 at. pct to 60 at. pct Ni.1 According to Bradley and Taylor2 and to cooper,' it possesses a defect lattice in which departures from stoichiometry in the direction of decreased nickel content lead to the presence of vacant nickel sites (although Cooper's work indicates that a small amount of substitution also occurs) whereas departures on the high-nickel side lead to substitution of nickel on aluminum sites. NiAl forms congru-ently from the melt at approximately 1650°C,1 and thus has a higher melting point than either of its component elements. Up to this time, although this and other high-melting intermetallic compounds have been suggested for elevated-temperature usage,4 only the hardness4 and a few tensile-strength measurements5 have been reported for NiAl at high temperatures. In the present investigation the effects of composition upon the compressive-strength properties in a range of 700° to 900°C have been measured for NiAl of several grain sizes. EXPERIMENTAL PROCEDURES The alloys were made as described elsewhere6 from an A1-46.8 at. pct Ni master alloy furnished by the International Nickel Co. with additions of high-purity nickel and aluminum. The charges were vacuum-induction-melted in A12O3 crucibles with small amounts of helium added to the atmosphere to suppress vaporization. They were cooled slowly from the melting temperature to achieve uniform grain size. In order to refine the as-grown grain size a special rolling technique was developed. Alloys were packed into 0.10-in. wall-type 302 stainless-steel tubes which were partially filled with magnesium oxide to prevent bonding between the alloy and the steel jacket. The ends of the tubes were closed by hot forging, and the packets were then hot-rolled. The alloys with greater than 50 at. pct Ni were rolled at 1100°C, but it was found necessary to increase the temperature to 1350° C before alloys with less than 50 at. pct Ni would roll without cracking. With these temperatures, reductions as high as 48 pct were achieved in a single pass. The rolled alloys will hereafter be referred to as "fine grained" whereas the as-grown material will be designated "coarse-grained''. The compression specimens were made by cutting square cross-sectional pieces, approximately 3/16 by 3/16 by 1/2 in., with a water-cooled diamond cut-off wheel from the as-grown or the rolled alloys. Specimens were ground to their final dimensions by polishing through 3/0 grit silicon carbide papers. The final shape was a rectangular parallelepiped of square cross section having a height-to-width ratio of 3:1. Compression testing was carried out in a compression rig of our own design mounted on an In-stron Floor Model. The specimen chamber could be heated to 1000°C and was controlled within ±2°C. The compression rig was enclosed within a bell jar and was maintained at a 50 µ of mercury vacuum throughout the duration of the test. The test cham -ber was heated from room to test temperature within 15 min. Specimens were then held at the test temperature 30 min prior to testing. Previous experiments indicated that no grain growth would occur within this time. An Instron Variable Crosshead speed unit was used to adjust for small variations in specimen lengths in order to have a constant initial strain rate, €, for all specimens of a group. For the fine-grained specimens the strain rate was changed rapidly at constant temperature by a factor of 10 with the speed lever on the Instron. For a given € the compression data was analyzed in terms of true plastic strain (E) and true compressive stress (0).

Jan 1, 1965

By K. J. McGrew, J. W. Murphy

Introduction Maximization of profit consistent with environmental protection is the principal goal of new applications development for any conventional or in situ mining technique. Efficient evaluation of all the parameters that contribute to mining costs and production hinges on proper design and evaluation of testing programs and data. The program discussed uses several field and laboratory procedures to estimate ore deposit characteristics and optimize lixiviant compositions. Ore characteristics and lixiviant compositions are then used in a long path leaching test (stream tube test). Stream tube test data are analyzed by mathematical models with computer assistance to predict such wellfield rate parameters as target metal production, lixiviant consumption, and restoration. When these predicted rates are combined with market values for target metals, capital expenditures, prices of lixiviant chemicals, and other economic variables (labor costs, power rates, and licensing fees), an assessment of the relative feasibility of various proposed mining plans is possible. The flowsheet in Fig. 1 illustrates this process. [ ] Field and Laboratory Procedures In general terms, the procedures followed in the evaluation of an in situ leaching application aim at accomplishing: •rapid leaching and maximum recovery of the target metal in a marketable form, •low consumption of lixiviant chemicals, •unquestionably satisfactory restoration of the mined aquifer, and •minimization of capital and operating costs for the above through development of an optimum mine plan. Keeping these goals in mind, the following minimum test program is generally recommended. Geology •Estimate of ore reserves and their variability. •Average disequilibrium value for uranium deposits. •Ore thickness, depth to ore, water level, degree of confinement, and consolidation. •Characterization of quality and quantity of other ore deposit constituents (e.g. sulfide minerals, ion exchange parameters). Hydrology •Single well pump and injectivity test. •Downhole vertical permeability test to compare flow rates of barren and mineralized formations. •Groundwater quality as it may affect licensing, hydro metallurgy, and restoration. Hydrometallurgy • Flask or autoclave tests for optimization of lixiviant parameters and determination of specific reaction rate constants. • Flask or autoclave tests for assessing amenability of lixiviant solutions with ore, consumption of lixiviant, stability of metal in solution contacting ore, and environmentally important species mobilized. • A long-path leach test for modeling the behavior of the lixiviant solution flowing through a long mineralized streamline (stream tube testing). •Metal recovery tests from lixiviant solutions (ion exchange, electrowinning, etc.). •Lixiviant regeneration tests. •Environmental restoration tests.

Jan 1, 1985

By Charles Goodale

THE principles and theory on which the U. S. mining law of 1872 was based are well understood, and have been discussed at great length by many writers. The papers by Dr. R. W. Raymond1 in the Transactions of the American Institute of Mining Engineers have covered the subject very fully, with explanations of practical results in many adjudicated cases. It is believed that the following instance of the application of the law in recent years will have some weight in a discussion of proposed changes in our mining laws. The litigation between the St. Louis Mining & Milling Co., and the Montana Mining Co., Ltd., a British corporation, over portions of the Drumlummon lode covered more than 20 years, and resulted in a judgment for damages in favor of the St. Louis Co. of such an amount that the Montana Co. declined to pay the judgment, and therefore lost the entire property. The Drumlummon lode claim in the Marysville district, Mont., was located in 1876 by Thomas Cruse. When he staked out his claim, he assumed that the discovery on the Drumlummon vein, and another showing of mineral about 200 ft. distant, were on the same vein, and the center line of the claim was given a course of N. 57'2'E. Development of the Drumlummon vein soon showed that its strike was about N. 15 E., and that the other outcrop was on the North Star lode; so it was inevitable that the Drumlummon vein would cross one or both side lines of the location, and the Montana Co. found it advisable to acquire adjoining claims on both sides of the Drumlummon, in order to avoid possible litigation over apex rights. They bought the Marble Heart, but would not purchase the Hopeful (see Figs. 1 and 2), at the terms proposed for the reason that exploration in the Cruse level had shown the vein to be barren in that region. The owners of the Hopeful were sinking an incline from that claim in 1889, and the Montana Co. enjoined them, contending

Jan 5, 1914

By John J. Dran

The elaborate analytical techniques for risk analysis used by the large mining companies in conjunction with the valuation of mineral reserve sites are totally inappropriate for the small miner. The small miner does not possess the financial and technical resources which are available to the large companies for such risk analysis. Even if these resources were available to him, the relatively small size of his investment would not justify a huge expenditure for risk analysis. What is required by the small miner is an improvement over the single point estimates provided by the valuation techniques that he currently uses. Such improvement should provide an indication of the extent to which the true value (known only after the fact) might differ from his estimated value of the mineral reserve site. In addition, a rough indication of the chance of occurrence of various differences between the true and estimated values would be helpful to him. These improvements must be obtained at low cost to be useful to the small miner. Such improvements would have to be based on a simple system requiring very few additional estimates by the miner. The small miner is not accustomed to dealing with sophisticated risk analysis techniques. Hence, any complex, time-consuming approach would be doomed to disuse or possible misuse. A simple, uncomplicated approach requiring a minimum of additional estimates by the miner can be based on a system devised by Frederick S. Hillier Although Hillier's method can be applied to various mineral reserve valuation methods used by the small miner, this note is specifically oriented to the discounted cash flow model. The basic discounted cash flow (DCF) approach provides a single point estimate of value and introduces the concept of risk (i.e. the possibility that the annual cash flows may differ from their estimated values and thus lead to an incorrect investment value) through the use of a risk-adjusted discount rate. This approach simply lowers the present value estimate with increases in the discount rate (i.e. increases in the risk assessment). The single point estimate still remains. Although the lower value estimate makes it less likely that the risky investment will be deemed profitable and undertaken, it provides no indication of risk that is suitable for examination and analysis. In addition to the "best guess" estimate of annual net cash flows required in the DCF model, application of the Hillier risk analysis model requires that the miner

Jan 1, 1976

By Thomas L. Kesler

Essentially all of the barite produced in Georgia has come from the Cartersville district in the northwest part of the state. The earliest recorded shipment of ore, 60 tons, was made in 1894.1 With the exception of the four-year period 1931 to 1934, the separate yearly output has been recorded and published since 1915, whereas the total yearly output of the United States has been published since 1880. The separately recorded production of Georgia (Cartersville) through 1947 is 2,232,544 short tons valued at $14,900,746,2 but unpublished data on the period 1931 to 1934, plus the estimated unrecorded output prior to 1915, make the actual total about 2,400,000 short tons. This is about 21 pct of the total production of the United States, which, through 1947, is 11,328,440 short tons valued at $71,683,386.2

Jan 1, 1949

By Mungo Park, C. Baring Horwood

This paper is intended, in the light of recent investigations, to call attention to some of the essential features of good practice in sampling and mine-valuation. Mine-sampling may be divided broadly into two classes: (1) development-sampling and cornputatioll of ore-reserves; and, (2) stope-sampling and estimation of stope-values. Development-Sampling. It is with development-sampling only that this paper deals— the term development being taken to mean the opening-up of a mine by cross-cuts, drives, connections, etc., preparatory to actual extraction of the ore for milling. In development-sampling the work of the sampler and the consequent estima-

Jan 1, 1909

By ROBERT E. HARDWICKE

THE QUESTION of whether the production of oil should be limited to market demand has been constantly discussed during the last two years. Oil men, legislatures and courts have reached highly conflicting conclusions. Opponents of limitation to market demand assert that it is a scheme of the big purchasing companies to fix prices and to create a monopoly. Proponents, on the other hand, declare that such a limitation is necessary to prevent physical waste and that the effect on prices is merely incidental. A brief review of market demand legislation will disclose the confusion existing. The laws of Oklahoma,' prohibiting waste of oil and gas, specifically' authorize limitation to market demand as a method of preventink such waste. These laws and the proration orders based thereon have been upheld by the Supreme Court of Oklahoma, by several three-judge Federal District Courts, and by the Supreme Court of the United States.' Kansas has a similar law3 but no case has been found which discusses its validity. About a year ago the California Legislature passed a comprehensive conservation act, generally known as the Sharkey Bill giving authority to restrict production to an amount representing current requirements for use, taking into consideration oil and products in storage. This may be considered as equivalent to limitation to market demand. The Act was defeated upon referendum vote after a hard fought campaign in which it was charged that the Act would result in destruction of the independent operators.

Jan 1, 1932

By K. H. G. Ashbee, J. W. Heavens

One consequence of the distribution in orientation of Bragg diffracting planes in an elastically bent foil is that simultaneous diffraction occurs from ±g pairs, where g is the reciprocal lattice vector to a diffracting plane. If such Bragg contour pairs are indexed, then the variation in orientation with respect to the incident electron beam is known. This note describes a construction by means of which Bragg contour pairs may be indexed by inspection. Referring to Fig. 1, the Ewald sphere radius is l/h, where is the wavelength of the electron beam, and the half spacing of first-order reciprocal lattice planes is l/d, where d is the corresponding spacing in direct space. The angle subtended by the zero and first-order planes at the center of the Ewald sphere is a = sin-' Thus, to represent a pair of first-order Bragg contours on a stereographic projection, measure ±a from, and along the normal to, the zero-order plane. The traces of the required Bragg contours pass through these points and parallel to the zero-order trace. In practice, it is desirable to enlarge a stereographic projection of the zero-order planes before making the construction. As an example, a stereographic projection of first-order Bragg contours up to line 27 for an fcc crystal is given in Fig. 2; if required, higher-order contours can easily be added. Fig. 2 is, of course, a map of first-order Brillouin zone boundaries. One use of this construction is the measurement of large elastic fields in electron microscope specimens. Fig. 3(a) shows a pattern of Bragg contour pairs due to lattice distortions near a large precipitate. This particular example is of a T-phase precipitate in Hidu-minium 54 (A1 + 6 wt pct Cu, 0.5 wt pct Mn). Foil buckling is produced by annealing during observation and may be evidence for evaporation from the precipitate.' Comparing Figs. 2 and 3(0), it is evident that the axis of high symmetry in Fig. 3(a) is [lll]. The strain in a bent foil is approxinlately t/2r, where / is the foil thickness and ? the radius to which the foil is bent. From the projections of grain boundaries and of helical dislocations, it was estimated that ( - 3000A, and values for ? were obtained from the

Jan 1, 1968

By C. M. Shigley

The record of the largest magnesium plant in the country utilizing sea water as a primary raw material stands as another victory in the struggle for large-scale production of pure chemical elements from the oceans. Bromine was the first element to be economically and commercially recovered when, in 1933, a six million pound per year unit was built on the Atlantic Coast near Wilmington, North Carolina, by the Ethyl-Dow Chemical Co.' The bromine was reacted with ethylene to produce ethylene dibromide, a necessary associate of tetraethyl lead in ethyl antiknock fluid. Within eight years that plant was doubled and redoubled, and another large unit was put into operation at Freeport, Texas, taking bromine from the Gulf of Mexico. In 1940, in fortunate anticipation of the impending demand for magnesium and the limitations of the production from natural brines, the Dow Chemical Co. turned again to the sea, and designed and erected a plant at Freeport to produce 18,000,000 lb. of magnesium per year from sea water.2 In March 1941, two months after the new plant had been put into successful operation, construction of an 18,000,000-lb. Government-financed addition was started. Late in 1941, as a part of the $400,000,000 defense program intended to produce 600,000,000 to 700,000,000 lb. of magnesium per year, Dow was asked to build and operate for the Government a 72,000- ooo-lb. plant near its original plant at Freeport. Within a few days after the Japanese made their attack at Pearl Harbor, preparation of a site was started at Velasco, Texas, for the construction of the Texas plant of the Dow Magnesium Corporation—the largest known magnesium plant utilizing sea water as its raw matcrial. Less than six months after the first piling was driven, urgently needed magnesium was in steady production. Five months later, the plant had exceeded its rated capacity. It remained above rated production until the general magnesium curtailment was applied to Government-owned plants in September 1944. Credit for the construction and operation record of the Dow magnesium plant must be divided among the efforts of a very determined group of men, an extremely favorable location, and a simple process. It is with the two latter aspects of the plant that this article will deal. The site for the new enterprise was chosen near Velasco, Texas, on property bordering the Brazos River at a point approximately 6 miles inland from the original magnesium plant and 7 miles inland from the Freeport Harbor on the Gulf of Mexico. This location was far enough away from the operating units to reduce both interference from construction and the vulnerability of closely bunched manufacturing operations to the then feared air attack. Yet the distance inland was not too great for the economical construction of a barge canal from the harbor to serve both the transportation of raw

Jan 1, 1949

By Laurance Reid

HIGH compression ratios, resulting from high injection pressures and relatively low recovery process pressures, constitute a major problem, which has confronted those engaged in gas recycling for condensate production since the beginning of that practice. Despite the numerous process developments and improvements, no entirely satisfactory solution for this prob-lem has been presented to date. Often, where the residue gas from the recovery process must be recompressed for subsurface injection, there is a substantial difference between the required injection pressure and the plant-operating pressure required to produce maximum recovery of condensate. These limitations result in high compression ratios, which, in turn, neces-sitate excessive compressor investment and operating cost. As an alternative, the operating pressure may be increased in order to lessen the compressor requirements but such a saving often is purchased at the expense of decreased condensate recovery, caused by operation at the higher pressure. Regardless of the choice, the net result is a diminished return on the capital invested in the project. The goal of future development in this field must be the complete recovery of all valuable hydrocarbon components in the reservoir fluid at pressures that, regarded as compressor suction pressure, will require minimum compressor horsepower to inject the residue gas into the formation. A com-pression ratio of 1.5 has been established as an optimum for modern compressor equipment." Therefore, in order to con-form to this optimum condition, a 3000-lb. injection pressure would require that the condensate recovery process be operated at 2000 lb. per sq. inch.

Jan 1, 1940