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By E. D. Gardner, E. M. Sipprelle

The Synthetic Liquid Fuels Act (58 Stat., 190; 30 U.S.C. Sup., Secs. 321-325) was approved by Congress April 5, 1944; it directed the Bureau of Mines to build demonstration plants to produce synthetic liquid fuels from coal, oil shale, and agricultural products. The most important oil-shale deposits in the United States are in the Green River formation of Colorado, Utah, and Wyoming. The oil shale of western Colorado generally is more amenable to exploitation, more persistent, and apparently richer than elsewhere in the Rocky Mountain Region. It occurs at the top of a high plateau surrounded by bold, nearly vertical escarpments 500 to 600 ft in height. The top 400 to 500 ft of these escarpments comprises an oil-shale measure that averages 15 gal of shale oil per ton; the bottom 70 90 100 ft of the measure, called the Mahogany Ledge, averages over 30 gal per ton. The full measure in a 1000-square-mile area is estimated to contain 300 billion barrels of shale oil;' the Mahogany Ledge is estimated to contain 100 billion barrels of oil. These estimates are based on numerous surfac,e samples and on core-drill holes drilled by the Government and by private enterprise. The oil-shale beds are undisturbed and lie nearly horizontal. The name "oil shale" is unfortunate, as the rock is a tough, strong marlstone. Organic matter named "kerogen" is a constituent of the rock. The oil-shale demonstration mine is on Naval Oil-Shale Reserve No. 1; it is about 5 1/2miles by mountain road from the plant site, which, in turn, is 2 miles from U.S. Highway 6 and 10 miles west from Rifle, Colo. The highway parallels the Colorado River, the Denver and Rio Grande Western Railroad, and a 66,000-volt public-utility power line. Early in the program it was realized that an oil-shale enterprise would have to be on a large scale to be commercial, and that unusually low mining costs would be necessary. The physical characteristics of the Mahogany Ledge and an overlying roof stone are unusually favorable both for large-scale operation and low mining costs. Quarry practices largely will be followed underground to mine the Mahogany Ledge. The aim has been toward complete mechanization of all mining operations. A mining unit would comprise a square mile containing 100,000,000 tons of oil shale with allowance for mining losses. An investment of $1,000,000 would be $0.01 a ton; such an expenditure, therefore, could be made to save, say, $0.015 per ton daily operating cost. A goal of a mining cost of $0.50 per ton was set up in 1945. Open-cut mining costs then were about $0.25 per ton of material handled; it was hoped that a cost double this amount could be obtained in mining the Mahogany Ledge. Costs of labor and supplies have increased since 1945 and so has the selling price of petroleum products. To those unacquainted with the character of the Green River deposits, the name "shale" suggested high mining costs. Others assumed that coalmining costs of $2 to $5 per ton would apply. To many, the expected mining costs appeared the principal handicap to the establishment of an oil-shale industry. The purpose of the Bureau of Mines is to demonstrate methods and to establish costs for mining the oil shale on a large scale. It is hoped this work will lead to the establishment of a large-scale, commercial oil-shale enterprise.

Jan 1, 1950

By T. Cantwell, N. C. Rasmussen, H. E. Hawkes

Beryl is a mineral that may be difficult to distinguish from quartz by casual field inspection. The easily recognized green color and hexagonal crystal form of coarse-grained beryl are by no means universal, even in beryl from pegmatitic deposits. If it occurred as a fine-grained accessory mineral in an igneous rock, it would almost certainly escape detection unless samples were submitted for petrographic or chemical analysis. There may be substantial deposits of some beryllium mineral, other than beryl, that has been overlooked because that mineral also closely resembles the common rock-forming minerals. A reliable and simple method of identifying beryllium minerals and determining the beryllium content of a rock would be helpful in exploration. This article describes preliminary experiments in applying nuclear reaction to the qualitative identification of beryl and to the semiquantitative determination of the beryllium content of rock samples. Gaudin,1,2 the first to apply a nuclear reaction in detecting beryllium minerals, developed a method that irradiates the sample with gamma rays, which react with beryllium nuclei to produce neutrons. The neutrons are then measured with standard equipment. The cross section for this reaction is about 1 millibarn. The cross section is a measure of the probability that a reaction will take place, for example, between a beryllium nucleus and an incident gamma ray or alpha particles.3-5 At 1-millibarn cross section for the reaction, satisfactory performance required a source strength of the order of 1 curie (3.7 x 10"' disintegrations per sec, where each disintegration releases one or more gamma rays). The reactions will not take place if the gamma radiation is below a minimum energy, in this case 1.63 mev. The size of the source and the energy of the radiation made heavy shielding necessary for these experiments, both to reduce the background count of the neutron counter and to safeguard personnel. The original discovery of the neutron by Chad-wick in 1932 resulted from experiments with another nuclear reaction, induced by bombarding beryllium with alpha particles in which the products are carbon-12 and neutrons. The equation for this reaction is as follows:' " ,Be" + ,He'? 6C12 + 8,n' [1] re-particle neutron In the above nuclear equation (Eq. 1), the sub- script number indicates the number of protons in the nucleus (the atomic number) and the superscript the total number of neutrons and protons (approximately the atomic mass). For the alpha-neutron reaction the cross section is about 250 milli-barns, or 250 times that of the gamma-neutron reaction used by Gaudin. The positively charged alpha particle is repelled by the positive charge of the beryllium nucleus; it must, therefore, have a certain minimum energy in order to approach close enough to the beryllium nucleus to react. For reaction with the beryllium nucleus, the lower limit of the alpha-particle energy is 3.7 mev. The alpha-neutron reaction, with polonium-210 as an alpha source, was selected for the present experiments. Alpha particles are emitted by polonium-210 at 5.30 mev, which is adequate for the reaction with beryllium. Furthermore, this isotope of polonium emits alpha particles with negligible associated gamma radiation, thus eliminating the necessity of shielding. The half-life of polonium-210 is 138 days. Inasmuch as alpha particles carry a possible charge and are large compared with most nuclear particles, their energy is rapidly dissipated in passing through matter. Their range in standard air is 3.66 cm,3 and they penetrate only a few tens of microns into a mineral sample. The short range in air can be minimized by preparation of a flat sample surface that can be brought very close to the alpha source during analysis. On the other hand, short range of alpha particles in air lessens the radiological health hazard and makes it possible to use this method without shielding. It must be emphasized, however, that the alpha emitters are potentially very dangerous if they enter the human body. Polonium must be handled with extreme caution. The literature has reported experiments on the yield of neutrons from reaction of alpha particles with beryllium nuclei. Feld" reports that in intimate mixtures of polonium and beryllium, 3 x 106 eutrons per sec are produced per curie of polonium. Elsewhere in the same reference it is stated that a sandwich-type source yields about one third as many neutrons as an intimate mixture. A table of neutron yields for full energy polonium alpha-particles on thick targets as reported by Anderson7 is the basis of Table I. From Table I it can be deduced that the elements most likely to interfere, i.e., those that also produce neutrons when bombarded by alpha particles, are boron and fluorine. These data also show that it will probably not be possible to determine very small quantities of beryllium in rocks because of the masking effects of the major elements, sodium, magnesium, and aluminum. The neutrons emitted in the alpha reaction are detected by another nuclear reaction. Either of the

Jan 1, 1960

By A. S. Yue

The movphology of the Mg-32 wt pct Al eutectic has been studied as a function of freezing- rate and temperature gradient. At slow freezing rates a lamellar eutectic was formed; whereas, a rod-like eutectic was generated at fast rates. The inter-lamellar spacing increased as the freezing rate decreased in aggreement with theoretical predictions. Lamellar faults, morphologically similar to edge dislocation models in crystals, were responsible for the subgrain structures in the eutectic mixture. A linear increase in fault density with freezing rate was observed. Fault concentl-ations of the order of 10 per sq cm for a range of freezing rates from 0.6 to -3.0 x 10 cm per sec were estimated. The transformation from lamella?, to rod-like morphologies was determined experimentally to be dependent on the freezing rate and independent of the temperature gradient. Moreover, the number of rods formed per- unit cross-sectional area increased exponentiallv with increasing freezing rote. BRADY' and portevin2 classified eutectic structures into lamellar, rod-like, and globular according to the morphology of the solid phases present. Although this classification is quite descriptive, very little has been reported on the details of the mechanism by which the eutectic structures are formed. Recent work by Winegard, Majka, Thall, and chalmers3 and by chalmers4 on lamellar eutectic solidification suggest that the maximum thickness of the lamellae decreases with increasing rate of solidification due to inadequate time for lateral diffusion. scheilS and Tiller' have shown theoretically that the lamellar widths indeed depend on the solidification rate. However, there has been no experimental evidence to support the theory. Chilten and winegard7 have studied the interface morphology of a eutectic alloy of zone-refined lead and tin. They found that the lamellar width decreased as the freezing rate increased in agreement with the theoretical predictions of scheils and Tiller.' More recently, Kraft and Albright' have investigated the microstructures of the A1-CuA12 eutectic as a function of growth variables. They observed lamellar faults present in the lamellar eutectic, similar to edge dislocation models in crystals. Furthermore, Kraft and Albright reported that they could not designate which extra lamellar was responsible for the formation of a lamellar fault even under electron microscopic magnification. In this paper, the morphology of the Mg-A1 eutectic structure is described. The effects of freez- ing rate on the interlamellar spacing and on the lamellar fault density are presented in detail. The transformation from lamellar to rod-like eutectics is discussed in terms of the freezing rate and the temperature gradient. EXPERIMENTAL PROCEDURE The experimental details of alloy preparation, the decanting mechanism and the determinations of the freezing rate and the temperature gradient have been reported elsewhere. Measurements of plate-edge angles were made with a microscope. The true angles used to determine the interlamellar spacings were determined by a two surface analysis technique.'' Since the decanted interface structure does not represent the true eutectic morphology on the solid,g all measurements were made from an area in the solidified bar behind the interface. Measurements of the apparent interlamellar spacings between the two phases of the eutectic were made on a photographic negative by means of a calibrated magnifier. Each value listed in Table I represents the average of thirty measurements on one negative. In general, these measurements are approximately equal with an error of less than pct. The average rod diameter for each specimen was also measured on a magnified photomicrograph. Each value of the diameter represents the average of fifty measurements. RESULTS AND DISCUSSION The experimental observations and their discussion to be presented here are restricted to the morphology of the eutectic structure and to the effects of the freezing rate and the temperature gradient on the solidification of eutectics. INTERLAMELLAR SPACING It has been shown previouslyg that the micro-structure of the decanted interface and the longitudinal section of the Mg-A1 eutectic is characterized by the presence of both lamellar and rod-like morphologies. The lamellae become more regular as the freezing rate is decreased. A three-dimensional photomicrograph representing a perfect lamellar morphology is illustrated in Fig. 1. The lamellae of the top and longitudinal sections of the specimen are regularly spaced while those in the transverse section are not quite straight and parallel. Their parallelism is slightly distorted because fault lines producing a discontinuity are present. A method for calculating the interlamellar spacings A, is described in Appendix 1. The true

Jan 1, 1962

By Henry Mulryan

THE largest and purest known deposit of diatomite is being actively mined and processed 3 ½ miles south of Lompoc, Santa Barbara County, Calif., by the Johns-Manville Products Corporation. The workings FIG. 1.-LOCATION OF DIATOMITE DEPOSIT AT LOMPOC. cover 4000 acres, the depth of economically recoverable diatomite being 1000 ft. (Fig. 1). Lompoc, a community of 2500 population, is situated in the Santa Ynez River Valley 10 miles inland from the Pacific Ocean. It is 44 miles

Jan 1, 1936

By W. B. Braden

This paper presents a suitable method for predicting gas-free oil viscosities at temperatures up to 500F knowing only the API gravity of the oil at 60F and the viscosity of the oil measured at any relatively low temperature. The API pravity and the one viscosity value are used as parameters to determine the slope of a straight line on the ASTM slanaord viscosity-temperature chart. Then, knowing the slope of the line and one point on the line, the vrscosities at higher temperatures can be determined. The line slope correlations were developed at I00 and 210F since viscosity data are frequently measured at these temperatures. A procedure is given for predicting line slopes from measurements at other tetnperatures. A nomogram is furnished for solving the relationship. The correlation has been evaluated at temperatures up to 5OOF for oils varyzng in gravity from 10 to 33 " API. The correiution is applicable only to Newtonian fluids. Comparison at 500F of true viscosities and those predicted from values at 100F shows an average deviation of 3.0 per cent (maximum deviation of 6.0 per cent). Predictions from the values at 21 0F for the same oils how an average deviation of 1.5 per cent (maximum deviation of 3.4 per cent). INTRODUCTION Correlations have been developed by Beal' and by Chew and Connally' for predicting viscosities of gas-saturated oils at reservoir conditions. Each of these correlations requires a knowledge of the solution gas-oil ratio and the viscosity of the gas-free oil at the reservoir temperature. For temperatures below 350F, measurements of the gas-free oil viscosities can be made easily using commercially available equipment. In thermal recovery processes, however, reservoir temperatures well in excess of 350F are encountered. Viscosity measurements at such conditions are more difficult and time consuming and require modification of existing equipment or the construction of new equipment. Measurements are further complicated by the difficulty of handling highly viscous oils associated with thermal recovery processes. Therefore, it is desirable to have a correlation which allows accurate prediction of viscosities at high temperatures. A commonly used technique for predicting viscosities at high temperatures is to measure the viscosities at two lower temperatures, plot the values on ASTM standard viscosity-temperature charts and extrapolate to the temperatures desired. If either of the values is slightly in error, the extrapolated value can be significantly in error. To justify an extrapolation, three points are actually necessary. This procedure can consume much time, particularly with heavy oils. Considering the cost of viscosity measurements, it would be desirable to eliminate the need for direct measurements by having correlations which would allow viscosity predictions from other physical or chemical properties. Beal1 investigated the possibility of correlating viscosity with oil gravity at temperatures from 100 to 220F. While showing that a general relationship exists, he also found significant deviations. It is possible that correlations will be developed based on oil composition as more information becomes available. While not eliminating the need for viscosity rneasurements, the method presented herein requires that only one viscosity measurement be made. The API gravity must also be known. The theory is based on the fact that the viscosity of paraffins (high gravity) changes less with temperature than does the viscosity of naph-thenes or aromatics (low gravity). The gravity. therefore, is used as a parameter to determine the slope of a straight line on the ASTM standard viscosity-temperature charts. The correlation is applicable only to Newtonian oils, and deviations due to thermal decomposition and nonhomo-geneity cannot be predicted. Oils containing additives have not been evaluated. PROCEDURE Fifteen oils were used in developing the correlation; eight were crudes and seven were processed oils. Oil gravities varied from 9.9" API (naphthene base) to 32.7' API (paraffin base). The temperature range studied was 81 to 516F. Each oil used had a minimum of three viscosity measurements and each plotted essentially as a straight line on the ASTM charts. In all, 91 viscosity measurements were used in the correlation. Saybolt, rolling ball and capillary tube viscometers were used for the measurements. Viscosity data for Samples 1, 2, 4, 7, 10, 11 and 14 were obtained in Texaco, Inc. laboratories. The data for Samples 3, 5, 6, 8, 9, 12 and 15 were from Fortsch and Wilson,3 and data for Sample 13 were from Dean and Lane.' All data points used in the correlation are plotted in Fig. 1. It is seen that some of the viscosity values deviated slightly from the straight-line plots at the higher temperatures. Properties of the oils after exposure to the

Jan 1, 1967

E. A. H. Tays, San Blas, Sinaloa, Mex. (communication to the Secretary*):—The results obtained by Messrs. Hofman and Hayward in their experiments, proving that a low percentage of copper sulphate with a variable percentage of salt, depending on the ore, gives the best results, confirm practical mill-work which I did in 1895. I have none of my notes, taken at the time, to refer to, so have to rely solely on memory, which precludes the conciseness that is alway desirable. In 1894 I took charge of the plant of the San Rafael Company, near Chinipas, Chihuahua, Mex., which at that time was treating a very refractory ore carrying about $15 in gold and from 20 to 25 oz. of silver per ton, the bullion being about 300 fine in gold. The silver in the ore was in the form of a sulphide. Although carrying an average of 0.75 oz. of gold per ton, free gold could rarely be seen by panning, but upon roasting a sample of the ore the gold became visible at once—a result which was discovered by chance and used to advantage later. In order to utilize the old mill to the best advantage, it was decided to use pan-amalgamation after roasting. The roasting, done in a lime-kiln, was similar to the ordinary " burning " operation. The roasted ore was trammed to the mill-bins and crushed by 10 stamps to pass a 30-mesh screen. The pulp was de-watered and fed to four 1-ton pans. My recollection is that upon starting the mill-work, the charge contained 1.5 lb. of copper sulphate and 5 per cent. of salt per ton. From the start the extraction was unsatisfactory and the loss of quicksilver was very large. Experiments were then carried out on a working scale. First, the quantity of copper sulphate was increased 4 oz. at a time; then it was reduced

Jan 1, 1910

By H. A. Doerner, F. D. DeVaney, J.B. Clemmer

Production of magnesium metal in the United States during the past decade has increased from less than 600,000 lb. in 1928 to more than 4,800,000 lb. in 1938.1 The growing industry has stimulated interest in methods of production and in sources of raw material. All of the present domestic production is from brines. However, the availability of large tonnages of magnesite in the state of Washington, together with the possibility of cheap power, have created interest in the utilization of magnesite for the production of magnesium metal as well as for other purposes. Magnesite, the carbonate of magnesium (MgCO3), usually is associated with limestone (CaC03) and dolomite (MgCO3. CaC03). It occurs in crystalline and microcrystalline (sometimes termed amorphous) forms.2 The more common crystalline mineral is found in various shades of white, gray, yellow and brown, the colors being due to impurities, chiefly iron. Magnesite has a hardness of 3.5 to 4.5 and a specific gravity of 3.0 to 3.1. It forms rhombohedra1 crystals in the hexagonal system, having a vitreous, pearly luster. The quarries and mines of the Northwest Magnesite Co. near Chewelah, Wash., are large producers of magnesite for refractories. The deposits are extensive, some veins being hundreds of feet wide. The boundaries of the veins are indefinite, and the magnesite is interfingered with dolomite. Calcite, talc, serpentine, quartz and shale are disseminated through the deposits. The quality of the ore cannot be determined by appearance or by simple tests; chemical analysis is required. These features make it difficult to determine the boundaries or total quantity of workable ore.3 Only the higher-grade ores are mined, and a considerable proportion of the magnesite content is discarded by hand-sorting and log-washing methods. After calcining, the sorted product meets the specifications for usual refractory material, as it contains approximately 81 per cent MgO, 7 per cent SiO2, 6 per cent CaO and 6 per cent Fe203 + A1203. A sample of the reject material had the following analysis after calcining: 65.4 per cent MgO, 6.3 CaO, 21.1 SiO2 and 6.5 R2O3. The percentage reported as R2O3 includes compounds whose chlorides are acid-soluble but give precipitates in ammoniacal solution that are ignited and weighed. The more common constituents are Fe2O3, A1203 and TiO2. The sorted magnesite product is not the best grade. even for refractory purposes, and leaves much to be desired for a reduction process. The rejected material contains a large proportion of magnesite. It is apparent that an effective concentration method would yield a higher recovery and a better product. In general, the refractory grade is not suitably pure for other uses. Recent developments in the production of

Jan 1, 1943

By J. B. Clemmer, F. D. DeVaney, H. A. Doerner

Production of magnesium metal in the United States during the past decade has increased from less than 600,000 lb. in 1928 to more than 4,800,000 lb. in 1938.1 The growing industry has stimulated interest in methods of production and in sources of raw material. All of the present domestic production is from brines. However, the availability of large tonnages of magnesite in the state of Washington, together with the possibility of cheap power, have created interest in the utilization of magnesite for the production of magnesium metal as well as for other purposes. Magnesite, the carbonate of magnesium (MgCO3), usually is associated with limestone (CaC03) and dolomite (MgCO3. CaC03). It occurs in crystalline and microcrystalline (sometimes termed amorphous) forms.2 The more common crystalline mineral is found in various shades of white, gray, yellow and brown, the colors being due to impurities, chiefly iron. Magnesite has a hardness of 3.5 to 4.5 and a specific gravity of 3.0 to 3.1. It forms rhombohedra1 crystals in the hexagonal system, having a vitreous, pearly luster. The quarries and mines of the Northwest Magnesite Co. near Chewelah, Wash., are large producers of magnesite for refractories. The deposits are extensive, some veins being hundreds of feet wide. The boundaries of the veins are indefinite, and the magnesite is interfingered with dolomite. Calcite, talc, serpentine, quartz and shale are disseminated through the deposits. The quality of the ore cannot be determined by appearance or by simple tests; chemical analysis is required. These features make it difficult to determine the boundaries or total quantity of workable ore.3 Only the higher-grade ores are mined, and a considerable proportion of the magnesite content is discarded by hand-sorting and log-washing methods. After calcining, the sorted product meets the specifications for usual refractory material, as it contains approximately 81 per cent MgO, 7 per cent SiO2, 6 per cent CaO and 6 per cent Fe203 + A1203. A sample of the reject material had the following analysis after calcining: 65.4 per cent MgO, 6.3 CaO, 21.1 SiO2 and 6.5 R2O3. The percentage reported as R2O3 includes compounds whose chlorides are acid-soluble but give precipitates in ammoniacal solution that are ignited and weighed. The more common constituents are Fe2O3, A1203 and TiO2. The sorted magnesite product is not the best grade. even for refractory purposes, and leaves much to be desired for a reduction process. The rejected material contains a large proportion of magnesite. It is apparent that an effective concentration method would yield a higher recovery and a better product. In general, the refractory grade is not suitably pure for other uses. Recent developments in the production of

Jan 1, 1943

By V. Balasubarmanian, Rajendra Kumar

ISOTHERMAL formation of martensite in a copper-aluminum-nickel alloy was previously reported by Hull and Garwood.' In the present work an attempt has been made to investigate some of the character- istics of the formation of isothermal martensite in binary copper-aluminum alloys containing 14.00 and 14.50 pct Al, respectively. Chill-cast alloys were prepared from OFHC copper and aluminum of greater than 99.5 pct purity. They were homogenized for 24 hr at 950° C. Polished samples were soaked at 1000°C and quenched in water to retain the p phase untransformed; martensite did not form during the quench. The surface was then repolished for isothermal microscopic studies at room temperature. The salient features of the martensitic transformation in copper-aluminum alloys observed in this investigation are: a) The transformation progresses (i) by nuclea-tion at new sites and (ii) by simultaneous slow isothermal growth of existing martensite plates. Slow isothermal growth of martensite has previously been observed by Holden2 in an uranium-chromium alloy and by Hull and Garwood in copper-aluminum-nickel alloy. b) Martensite plates nucleate preferentially at the pin holes formed during the casting of the specimen, Fig. 1. c) Some of the martensite plates pass right through other plates lying in their path, Fig. 1. d) Martensite plates cross grain boundaries without any change in the direction of growth. e) An irregular network of markings, Fig. 2, appears simultaneously with the formation of martensite. It was less prominent in the case of 14.5 pct alloy. The markings may arise due to spontaneous deformation under the lattice strains of the martensitic transformation. Crossing of martensite plates was first observed by Kulin and cohen3 when a high-nickel steel was cooled to 77°K. They suggested that the rapidly advancing plates atquire considerable kinetic energy and strike the obstructing plate with a momentum so as to nucleate the process on the other side of the plate. This, however, fails to explain the present observation where the slow isothermally growing martensite plates cross each other. Such plates would not possess large momentum to bodily displace the obstructing plate. Fig. 1 shows the martensite plates crossing each other without body displacements. This should be contrasted with Fig. 3 of Kulin and Cohen's paper where crossing of plates is accompanied by shearing or body displacements of the plates. The present observations can, how-

Jan 1, 1961

By J. A. Bownocker

THE production of oil in Ohio, in 1924, was characterized by no marked or surprising change. Low prices and the absence of promising territory made the year quiet. As is well known, Ohio has reached a state of "settled production," and the most that can be expected for the ensuing few years is to maintain the output at approximately the present figure 1921 7,335,000 1922 6,781,000 1923 7,085,000 Geographically, the Ohio fields may be divided into three areas, each of which gets its main supply of oil from a different stratigraphic horizon.

Jan 3, 1925

By J. A. Bownocker

THE production of oil in Ohio, in 1924, was characterized by no marked or surprising change. Low prices and the absence of promising territory made the year quiet. As is well. known, Ohio has reached a state of "settled production," and the most that can be expected for the ensuing few years is to maintain the output at approximately the present figure 1921 7,335,000 1922 6,781,000 1923 7,085,000 Geographically, the Ohio fields may be divided into three areas, each of which gets its main supply of oil from a different stratigraphic horizon.

Jan 3, 1925

By J. B. Clemmer, F. D. DeVaney, H. A. Doerner

PRODUCTION of magnesium metal in the United States during the past decade has increased from less than 6oo,ooo lb. in 1928 to more than 4,800,000 lb. in 1938.1 The growing industry has stimulated interest in methods of production and in sources of raw material. All of the present domestic production is from brines. However, the availability of large tonnages of magnesite in the state of Washington, together with the possibility of cheap power, have created interest in the utilization of magnesite for the production of magnesium metal as well as for other purposes. Magnesite, the carbonate of magnesium (MgCO3), usually is associated with limestone (CaCO3) and dolomite (MgCO3CaCO3). It occurs in crystalline and microcrystalline (sometimes termed amorphous) forms.2 The more common crystalline mineral is found in various shades of white, gray, yellow and brown, the colors being due to impurities, chiefly iron. Magnesite has a hardness of 3.5 to 4.5 and a specific gravity of 3.0 to 3.1. It forms rhombohedral crystals in the hexagonal system, having a vitreous, pearly luster. The quarries and mines of the Northwest Magnesite Co. near Chewelah, Wash., are large producers of magnesite for refractories. The deposits are extensive, some veins being hundreds of feet wide. The boundaries of the veins are indefinite, and the magnesite is interfingered with dolomite. Calcite, talc, serpentine, quartz and shale are disseminated through the deposits. The quality of the ore cannot be determined by appearance or by simple tests; chemical analysis is required. These features make it difficult to determine the boundaries or total quantity of workable ore.3 Only the higher-grade ores are mined, and a considerable proportion of the magnesite content is discarded by hand-sorting and log-washing methods. After calcining, the sorted product meets the specifications for usual refractory material, as it contains approximately 81 per cent MgO, 7 per cent Si02, 6 per cent CaO and 6 per cent Fe203 + A1203. A sample of the reject material had the following analysis after calcining: 65.4 per cent MgO, 6.3 CaO, 21.1 Si02 and 6.5 R203. The percentage reported as R203 includes compounds whose chlorides are acid-soluble but give precipitates in ammoniacal solution that are ignited and weighed. The more common constituents are Fe203, A1203 and Ti02. The sorted magnesite product is not the best grade, even for refractory purposes, and leaves much to be desired for a reduction process. The rejected material contains a large proportion of magnesite. It is apparent that an effective concentration method would yield a higher recovery and a better product. In general, the refractory grade is not suitably pure for other uses. Recent developments in the production of

Jan 1, 1940

By P. C. Badgley

The purpose of this paper is to demonstrate the usefulness of systematic analyses of weakness patterns. The term weakness here includes structural features such as fractures, foliation planes, lineaments and bedding. Many of these features are mapped by geologists in the field, but analysis of the field date is frequently overlooked. Examples are presented to show the value of such studies in petroleum and mineral exploration, in dam site selection, and in regional tectonic interpretations. Numerous theories have been presented to account for the mechanics and time of origin of fracturing. This is an extensive subject and cannot be reviewed in detail here. The reader may wish to refer to other papers.*"5 It is sufficient to say that most fracture patterns can be related to one or more of the following force mechanisms: compression, tension, torsion and fatigue (inheritance by upward propagation of pre-existing fractures). Fractures generally occur in sets in a district. The angular relationships and other characteristics of the individual sets frequently help in determining the force mechanism and movement history of the deformation. From a geometric point of view fractures are commonly referred to as longitudinal, cross, or diagonal (shear), depending upon their orientation relative to other major structural features such as anticlinal axes and so forth. These terms will be used from time to time and are illustrated schematically in Fig. 1. FIELD PROCEDURE AND TREATMENT OF DATA In fracture studies it is very important to collect adequate field data. Fig. 2 illustrates a notebook sheet for recording significant field observations in sedimentary rocks. Slight adaptations have to be made for igneous and metamorphic terrains. Fracture density and persistence are very important factors in petroleum exploration for fractured reservoirs and mineral exploration. The density for each joint set is recorded in terms of number of joints per linear yard. The total number of joints at any one

Jan 1, 1962

Upon the recommendation of its Technical Committee, The Com-pressed Air Society has adopted the following definitions of, certain terms. Displacement.-The displacement of an air compressor is the volume displaced by the net area of the compressor piston. Capacity.-The capacity should be expressed in cubic feet per minute, and is the actual amount of air compressed and delivered, expressed in terms of free air at intake temperature and at the pressure of dry air at the suction. Volumetric Efficiency.-Volumetric efficiency is the ratio of the capacity to the displacement of the compressor, all as defined above. Compression Efficiency.-Compression efficiency is the ratio of the work required to compress isothermally all the air delivered by an air compressor to the work actually clone within the compressor cylinder, as shown by indicator cards, and may he expressed is the product of the volumetric efficiency (the intake pressure and the hyperbolic logarithm of the ratio of compression), all divided by the indicated mean effective pressure within the air cylinder or cylinders.

Jan 8, 1918

I;. D. Godshall, Everett, Wash. (communication to the Secretary) : In Mr. Morse's interesting paper several statements occur which seem to require correction and comment. This is the more appropriate, since Mr. Morse has mentioned me by name, and has cited my "Review of the Russell Process,"* so that silence on my part might be taken as indicating an assent which I cannot give. On the first page of his paper Mr. Morse says that the " goingback " of chlorination was " the only difficulty encountered at Aspen," and adds that he has " never seen any explanation " of the cause. The plain inference is that he now fills this complete

Jan 1, 1896

By AIME AIME

DATA in this report enable comparisons to be made within the bituminous coal industry and comparison as well with copper and steel in respect to capacity and overdevelopment. The conclusions reached from the data will tend to correct numerous current misconceptions. The data have been prepared by various members of the Coal and Coke Committee of the A.I.M.E., from the most authentic sources avail¬able, and cover the period 1913-1924 wherever possible. CAPACITY AND OVERDEVELOPMENT Table 1 shows statistics for the industry, mainly from the U. S. Geological Survey sources, but partly from the U. S. Coal Commission reports. The mine capacity with equipment and labor as of given date is calculated for each state by obtaining the total man days worked as reported by the operators, and dividing this figure into the total production, getting the production per man day; this figure times the number of men employed times 308 (a theoretical full working year) equals estimated full-time capacity. Two major objections are made to this method-one that the total number of men employed is used instead of the number actually working, and the other that the number of days used only deducts Sundays and five holidays. Covering the first, the same number of men is used in estimating capacity as is used in actual production, and this condition exists at all times. Regarding the second, the opinion is general among coal men that 280 days is as great a figure as should be used, as it is practically impossible to keep any mine working full time at the same daily rate as when it is working part time. The capacity, as estimated on this basis, is much more nearly the true capacity, although even with present railroad efficiency this amount of coal could not be moved.

Jan 1, 1926

By ALEC CROWELL

Mississippi has had oil production for only the past six years and natural gas production of minor magnitude since' 1926. The search for oil and gas commenced in 1903 and 1496 wells had been drilled in search of oil and gas up to Jan. 1, 1946. As the year 1945 ended, 659 wells were producing oil and gas from 23 separate reservoirs. The production for the year was 8,353,719,000 standard cubic feet of natural gas measured on a pressure base of 15.025 lb. per sq. in. abs., 15.316,009 bbl. of oil¬field water and 19,093,766 bbl. of crude oil and condensate. Production for the year 1944 was 2,636,067,000 standard cubic feet of gas, 14,979,793 bbl. of salt water and 16,420,346 bbl. of crude oil and condensate.

Jan 1, 1946

By Robert L. Zook, Bernard J. Olup, James J. Pierre

Coal refuse slurry impoundments are dams constructed of coarse coal refuse to impound fine refuse (slurry) and water (25 to 30% solids). Both products are waste from coal preparation plants. A number of these structures in West Virginia, Pennsylvania, and Kentucky were investigated to determine embankment stability. During the investigation a variety of embankment designs were encountered. The investigation determined the soil and geological characteristics of the embankments and the sites. This was accomplished by a test drilling and monitor installation (observation wells and piezometers) program, geologic study, and large-scale mapping which allowed subsurface profiles of the embankments to be constructed. The laboratory testing program concentrated on textural classification of the coal refuse, permeability, and determining strength parameters to be utilized in the stability analyses. For the stability analyses, the modified Fellenius slip circle, simplified Bishop slip circle, and analysis for translational failure were utilized. In all stability analyses hydrostatic pressure and seismic acceleration probability were considered. This investigation indicated that 62% of the embankments analyzed were in a stable condition. The coal seam, the type of roof rock, and the gradation of the refuse influence the degree of compaction obtainable and the permeability of refuse. The shear strength of coal refuse appears to be controlled by its composition, moisture content, degree of compaction, amount and grain size of fines present. This investigation demonstrated these embankments should not be treated as pure state-of-the-art dams consideration must be given to the particular properties of coal refuse and the total refuse disposal system. Refuse dam slurry impoundments generally lack the site selection phase that is standard practice with siting most other types of dams.

Jan 1, 1976

By Charles H. Foreman

IN JUNE 1921, the Sullivan &lining Co., owned jointly by the Bunker Hill and Sullivan Mining & Concentrating Co. and the Hecla Mining Co, started work on the development of the Star Mine. The development work contemplated called for a crosscut from the Hecla workings on the 2000 level to the Star ledge. The length of crosscut necessary to encounter the Star ledge was approximately 8900 ft. from the Hecla shaft. By using workings formerly made by the Hecla Mining Co., only about 8100 ft. of actual crosscutting was necessary. This crosscut has a direction of S 20° W and would have a tendency to crosscut any ledges in the intervening ground.

Jan 1, 1924

By Morris E. Fine, Richard A. Kloske

The stress-strain beha1,ior in tension of Au-Ag alloy single crystals containing nominally 1,3, 5, 95, 97, and 9.9 at. pct Ag was studied uS strain role and lektlperalure down lo 4.2K. A slrain aging yield hob lc,rrs observed on aging under stress in the temperature range 30° lo 75°C. The species diffusing to the dislocation is thought to be a divacancy-solute complex wilh /he. solute then pinning the dislocation by short-Range ovdering and possibly Suzuki locking. At room tempevullcve the critical reso1ved shear stress .follo~c.s an empirical equation of the form tc = A +Bc' where A and B are 90 and 420 ,g per sy mm tor gold base alloys and 60 and 510 g p~r sq )11ttz .tor si1ver base alloys. This strengthening was attributed to a long-range size ejtect. The alloy slrenglliening at i.2'K is greafer than at room temperature. The additional atrloutzf was altribuled lo a uwak skovl-range i?~levacIion between the solute and dislocallon cove. The activation energy .tor deformation a/ 4.Z0h7 decreases on alloying. 11 increases irr other fee systetns. hi the 5 at. pcl Air-Ag- alloy in pmvlicular there is very extensive easy glide and lavge overshooting- of the synmetry line at 4.Z°K. There is also u sharp decrease in the vale of. strain hardenitlg near the widdle of stage II with the new rate bezng abold the sarne as tlzal In easy glide. This uws attributed to a sudden reduction of activity on the pvitrrarg sgstertr. In Au-Ag alloys the critical resolved shear stress Tc. at room temperature is essentially a parabolic function of atomic concentration:' the 50 at. pct Ag-50 at. pct Au alloy is about 10 times stronger than the pure metals. This strengthening occurs in spite of the similarity in valence and atomic size. Solid-solution strengthening in fcc metals is characteristically greater at low temperatures than at room temperature. In Ag-10 at. pct Au and Au-10 at. pet Ag; r, (20.4K)/Tc (300°K) is 2.3 and 2.5. respectively.- compared to 1.2 in pure silver.3 Suzuki' and Flinn5 explained the alloy strengthening at room temperature as a combination of Suzuki locking and short-range order hardening. The agreement between the computed and measured strengthening was very good: however, in Ag base-A1 alloys Hendrickson and Fine6 concluded that Suzuki locking resulted mainly in a yield drop effect. Recent reviews of the solid-solution strengthening in fcc metals by Fleischer2 and Haasen8, 9attributed the strengthening at room tenl-perature to the combined effect of atom nlisfit and change in shear modulus 011 the long-range stress field surrounding a dislocation. The parameter used by Fleischer was The shear tnoduli of Ag-0 to 6 at. pct Au alloys were measured by Pur-wins. Labusch. and Haasen.In While addition of 4 at. pct Au caused an appreciable increase in the C,, elastic constant. there was a decrease on increasing the solute to 6 at. pct Au: C,, and C :: were not measured in the 6 at. pct alloy. The greater solution hardening at low temperatures implies the presence of short-range interactions between the solute atoms and dislocations These include size and electronegativity effects. Whether the extra alloy strengthening at low temperatures is due to locking or friction hardening is still a controversy."".' In the present research the stress-strain behavior of Au-Ag single crystals containing 1 to 5 at. pct Ag and 1 to 5 at. pct Au was measured vs strain rate and temperature down to 4.2' K. Particular attention was paid to yield drop effects. These have not been previously reported. PROCEDURES The alloys were supplied by the Engelhard Industries. Inc.. as strips 0.050 by 0.250 by 12 in. The compositions are given in Table I. Single crystals were grown under static vacuum using a traveling molten zone technique. Crucibles shaped to the size of the strips were made of high-purity graphite prebaked for 24 hr at 1100°C in vacuum. The crucible and its charge were placed in

Jan 1, 1970