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By William P. Blake

The salt-beds at Salton, on the line of the Southern Pacific railway, in San Diego county, California, have been successfully worked for many years by the corporation known as the East Liverpool Salt Co., and the salt has been largely used upon the Pacific coast generally and in the interior. But the industry has lately been destroyed by the overflow from the Colorado river. The salt is dissolved, and the waves of the Salton sea now roll 50 ft. above the site of this once thriving and growing business. The salt-bed was evidently the residual accumulation from the waters of an ancient lake, which I have named Cahuilla, from the name by which a large part of the valley—the home of the Cahuilla tribe of Indians—is known. The deposit covered a comparatively small area in the lowest part of the valley, 280 R. or more below the sea-level. This depressed area is now generally known as the Colorado desert, but has a soil of wonderful fertility wherever water can be had on its surface. The deserted beaches, and the water-lines, only a few feet above tide-level, upon the rocks of the bordering mountains, as well as a great abundance of shells in the soil, all bear decisive testimony to the former occupation of the valley by water. The depression is topographically the northern end of the Gulf of California, from which it is now separated by the delta of the Colorado river, extending practically from the mouth of the Gila river across the valley to the coast mountains on the

Jan 1, 1908

By Jack Parker

The White Pine mine site lies five miles south of Lake Superior in Ontonagon County, Mich. Copper sulfide, mixed with some native copper, is mined by a room-and-pillar system from gently dipping Upper Kewee-nawan sediments. Depth of mining now varies from 700 to 1800 ft and the ore body continues to a depth of at least 3400 ft. An area roughly 21/2 miles square has already been mined. Mining height has varied from 61/2 to 22 ft. A rock mechanics program was set up in late 1963 to promote safety and mining efficiency. This note reports some of the findings. Rock Strength Compressive strength of small, dry specimens of sandstones, siltstones, and shales from the ore zone varies from 20,000 to 30,000 psi. This is intermediate between the softer coal mine sediments and the meta-morphic and igneous rocks of hard rock mines. Annual Cycle of Rock Failure Since 1963, every roof and pillar failure involving more than a few tons of rock has been examined and documented. Some 1500 stations have been installed for measuring convergence, -c1/1000 in., with Invar extensometers. At first it was thought that there was some kind of a cycle of roof failures; perhaps annual, perhaps even elated to the moon or to earth tides, but records (see

Jan 1, 1971

By Dorsey Hager

The possibility of oil and gas production in Alabama his been little considered as yet. Gas and some oil have been found in northwestern Alabama, near Birmingham, in the Pennsylvanian beds, but the oil and gas possibilities in the Cretaceous beds are not generally appreciated. The recent activity of oil companies in that State has attracted much attention, and in this paper the main structural and the general strati-graphic features are described. Four favorable areas are outlined. These contain folds of major interest. There are other favorable areas which have not been mapped-l Commercial pools discovered in this area would have the advantage of being near tidewater. Mobile, Ala., on the Gulf of Mexico, would be the logical site for refineries and shipping facilities. A pipe line could readily be laid to that city from the Hatchitigbee and the Jackson areas. The logical outlet for the Geneva and the Gordon areas would be Panama City, Ha., on the Gulf of Mexico. Topography The whole of the area under consideration lies in the Gulf coastal plain and slopes gently to the southwest and west. The elevations vary from 200 to 400 ft. (60 to 121 m.) above sea level. The streams have sunk their channels into this gently sloping plain, the main drainage flowing south or southwest into the Gulf of Mexico. Between the

Jan 1, 1918

By T. H. Courtney, G. W. Pearsall, J. Wulff

The mechanism, of the decrease in transition temperature of Nb3Sn was studied. Presintered Nb3Sn powder compacts were heated in a dynamic vacuum at elevated temperatures. Loss of tin resulted from these heat treatments and transition temperature as a function of tin loss was discontinuous at a critical value of tin loss. In general, decreases in transition temperature were correlated with deviations from AS a class, the A15 structure-type (also known as Cr3O or ß W) compounds have the highest superconducting transition temperatures.' In this class are stoichiometry and presence of vacancies in niobium sites. The effect of vacancy distribution on the physical properties of Nh3Sn is considered. It is concluded that the close-packed atomic A chain in the A3B A15 structure must be preserved both in coutinuity and direction if good superconducting properties are to he obtained. tempting to associate these high transition temperatures with the most unique crystallographic feature of the A3B structure: the three close-packed, orthogonal chains of A atoms.'0"' There are at least three principal mechanisms by which the perfection of these "A-atom chains" could be interrupted: changing stoichiometry, inducing disorder, or introducing vacancies. Departures from stoichiometry in either direction in V3Ga lower the transition temperature.7'8 In niobium-

Jan 1, 1965

By Arthur W. Sheafer

MR. ECKLEY B. COXE, in his able and interesting paper on " The Preparation of Small Sizes of Anthracite,"* read and discussed at the Glen Summit Meeting, October, 1891, refers to the reputed immense amount of coal contained in the culm-banks, which are the unsightly accompaniment of every mining operation in the anthracite coal-regions. Mr. Coxe thinks the available amount and value greatly exaggerated, giving among his reasons (1) the spoiling of the culm by mixing with other refuse; (2) its deterioration; (3) its destruction by fire ; and (4) frequent failures to realize expectations as to the size of the banks. These points are undoubtedly important factors in determining the advisability of working any individual bank, but they have a varying influence in the several regions, some prevailing more in one than in another. Although the amount of fuel lying waste in these banks is still an uncertain and undetermined quantity, yet no one can visit the Schuylkill region without being impressed with the fact that a considerable amount of culm, too valuable to be left merely to the mercy of the elements, surrounds and encumbers each site of an old or present colliery operation. The rapid increase in the number of washeries, and the demand for leases on old culm-banks, shows that, in the Schuylkill region at least, the question of deterioration doès not play an important part. The proportion of coal to refuse, the relative percentage of the sev-

Jan 1, 1895

By D. L. Gardner, H. L. Barr

The following report covers the history of the development of the mine, present equipment, methods and costs of mining and milling. In addition, a description of the ore deposit is given with emphasis on the origin of the fractures, mode and types of ore occurrence, and mechanics of granite emplacement. An endeavor has been made to present a complete and accurate statement of the San Mauricio mine, the highest grade gold mine in the Philippine Islands. Credit is gratefully acknowledged to the mine staff for descriptions and details regarding their particular field of work. All analyses were made by Mr. T. A. DeVore, head chemist, San Mauricio Mining Co. Messrs. Edward Wisser, J. E. Fyfe, A. F. Skerl and W. B. Meek, geologists, have contributed geologic information and ideas, for which thanks are extended. The Executive Committee of Marsman and Co., Inc., Managers of the Company, has kindly given permission for publication. Mr. J. B. Stapler, Division Manager, Marsman and Co., has had the courtesy to read the manuscript and to give critical and helpful suggestions. Location of Area and Scope of Work San Mauricio Mining Co. controls a group of 113 claims that lie immediately north of the town of José Pafiganiban (formerly Mambulao), Camarines Norte, Luzon, P. I. (Fig. 1). Exploration work commenced in the spring of 1934; active development began in the fall of that year and has continued to the present date. Mill construction was begun Ocl,. 15, 1935, and production started March 10, 1936. Total production to June 1, 1939, is P10,499,105.15 ($5,249,552.57).

Jan 1, 1941

By A. W. Furbank

In reviewing the aerial cameras produced in different countries, it becomes apparent that in nearly all of them an attempt has been made to secure the greatest possible angle of view. This angle, of course, is determined by the objective. The objectives most commonly in use in aerial cameras have a maximum angle of 65". The objective developed for this new Zeiss camera combines freedom from distortion and brilliant definition, with an angle of 95". Aerial mapping, it is claimed, has been placed on a different economic basis, and new possibilities presented, particularly in connection with automatic stereoscopic plotting instruments, to which some short references are made. One way of enlarging the angle of view is to couple several instruments with their axes convergent, thereby producing a multilens camera. Typical of cameras of this sort in the United States is the Bagley four-lens camera, which later was developed into the five-lens camera (T3-A) of the U. S. Air Corps. More recently, in order to get away from the unfavorable Maltese cross image field of the five-lens camera, and to obtain a more practical form, two five-lens cameras were combined. By using them in tandem and rotating them by 45" relatively to each other, a ten-lens camera was produced, covering an octagonal ground area, with a total angle of view of 140". Similar designs have been evolved in other countries. In all of them, however, a number of difficulties have arisen, quite apart from their large weight and high cost. Because of their complex mechanism, numerous shutters and magazines, and the high precision with which these parts must be interadjusted and synchronized, these cameras are far from dependable. Moreover, a multilens camera by itself does not yet constitute a complete outfit for producing pictures suitable for photogrammetric survey. Because all the component pictures, except the central one, are obliques, it is always necessary to employ rectifying apparatus which transforms the marginal views to the perspective of the central one. In multilens cameras with many individual magazines, it is not convenient to

Jan 1, 1941

By E. R. Borcherdt

Methods and equipment are subject to study in the Butte district at all times in order that advantage may be taken of any new developments that might serve to increase efficiency and lower costs. Detailed time studies of each operation involved in the entire mining process have been of invaluable assistance in analyzing the individual operation for possible improvement. In other words, the fact that a practice has been in vogue for many years does not exempt it from change provided an easier and cheaper method can be found. Exploration Ore occurs in the Butte district in such manner that structures must be drifted on, no matter how small or unimportant they appear when intersected by a crosscut. Parallel structures also add to the crosscut requirements. This prospecting work, which formerly was done entirely by drifting and crosscutting, is now being supplemented by diamond drilling, to aid in greatly decreasing the amount of waste. In long-shot prospecting, or in second or third class prospecting, where the chances of developing commercial ore are not very great, diamond drilling is of particular value. In prospecting where chances of encountering commercial ore are certain or where crosscuts can be used later for haulage or ventilation, drilling obviously is not applicable. Improvement in drilling machines and bits has contributed greatly to the present success of diamond drilling. For many Years square-set filled stoping was the principal mining method used in the Butte district. Later timbered and untimbered rill stopes were used, also some horizontal cut-and-fill stoping where both Ore and walls were particularly strong. Because of the amount of timber required for square-set stoping, and the relatively low production per stope unit, experiments with horizontal cut-and-fill stopes were begun in Ore bodies of which many had fairly weak walls. It was felt that increase in the speed of the stoping operation, followed closely by filling, to avoid weight being produced by permitting ore and walls to remain insufficiently supported over comparatively long periods, would maintain the walls and backs in safe condition without the use of timber and without ore dilution from wall slough. Cycles of drilling, scraping ore, and filling were devised, which have materially increased stope production and decreased timber consumption, so that both stope labor and supply costs were lowered appreciably without materially affecting grade control. In the larger mines of the district, where wide veins favor this stoping method, half of the total production is now being mined by horizontal cut-and-fill stopes (Fig. I). The increase of the filling rate demanded by the increased stoping rate was the greatest obstacle encountered in the accelerated stoping operations. Finally this problem was solved by replacing the time-honored method of transferring filling waste by small cars, which were hoisted or lowered in the auxiliary shaft, by a transfer

Jan 1, 1943

By John D. Sullivan, Chester R. Austin, Edwin J. Rogers

The problem of making a building unit combining the necessary physical and mechanical properties and good thermal insulation has been foremost in the minds of architects and ceramic and construction engineers for many years. This paper presents the results of studies on thermally expanding shales or clays to produce lightweight cellular products suitable for making building units. An expanded clay block suitable for building purposes should be large enough qo that substantial savings may be effected in labor costs in laying the wall. The permeability should be low and it should have sufficiently good "dry-wall" characteristics to permit exposing the exterior surface to the elements, and to permit plastering directly the inside wall surface. The thermal conductivity should be low and the mechanical properties should be adequate. Obviously, a unit possessing satisfactory qualities for constructing an - outside wall would be satisfactory for interior walls and for back-up purposes. The results of studies on bloating various shales or clays† and the properties of the expanded products are reported. In another paper1 basic factors involved in bloating of clays are discussed. Manufacturers of ceramic products, partitularly structural clay, may encounter bloating of the ware during burning, and precautions must be followed to avoid this phenomenon. About 1927 the C. F. Burgess Laboratories, Madison, Wis., while carrying on an investigation for the American Face Brick Research Corporation, conceived the idea of intentionally bloating clay while holding it in a restrained condition, with the hope of producing a unitary cellular mass. Work was carried on until about 1931, when studies were terminated because of business conditions. These studies were continued later by The Western Brick Co., Danville, Ill., which developed a process of "inwardly expansive bloating."² The major purpose of the latter investigation was to produce back-up tile to compete with concrete blocks made from Haydite or cinder aggregate. Haydite is a light-weight aggregate formed by heating certain clays or shales rapidly in a rotary kiln. While the investigations at the C. F. Burgess Laboratories or at Western Brick Co. were not carried far enough to lead to the commercial production of material for the construction of walls, particularly outside walls, they showed that certain clays could be thermally expanded and that it was possible to produce a material of low permeability with a large percentage of the total voids or cells closed. commencing in 1939, the Ozark Chemical Co. sponsored a research program at Battelle Memorial Institute for the Purpose Of determining whether it is technically feasible to make thermally expanded building units, and specifically to get answers to the following questions:

Jan 1, 1942

By J. B. Reed, T. A. Read, H. Rosenthal

Although the season cracking of brass has been a subject of experimental investigation for more than thirty years, the mechanism that is responsible for this phenomenon is still obscure. While at- tempts to elucidate the stress-corrosion cracking of some alloys have been relatively successful, the principal accomplishments made in the studies of the season cracking of brass have consisted of improved techniques for the fabrication of articles of alpha brass, which reduce the danger of season-cracking failure in service. The primary purpose of the present paper is to collect the published experimental data which appear to be of importance to the development of an adequate theory of the mechanism of the season cracking of brass. Some of the possible mechanisms which have been proposed will also be discussed, together with some promising avenues of future attack on the problems. Several excellent survey papers on season cracking are available, including the recent ones by Croft and Sachs(1)2 and by Gibbs(2). The principal facts concerning season cracking, as presented in these papers, may be summarized as follows. The season cracking of alpha brass is a special type of stress-corrosion failure, which may occur in atmospheres containing ammonia, air, and water vapor. The stress causing failure may be either the

Jan 1, 1945

By W. H. Brandt

ThEre has been much progress in the last two decades in understanding the hardenability of steel. Roughly, the progress has been along two lines, which may be designated as empirical and fundamental. This empirical work has progressed to the point where steels may be manufactured to the desired characteristics quite closely and heat-treatment and application problems can be approached with considerable confidcnce. Particularly noteworthy among the empirical work is that of Grossmann,12. who has given formulas for calculating hardenability as a function of composition, and the establishment of the isothermal transformation curve by Davenport and Bain.13 The latter does not fall entirely in the class of an empirical study, for while it provides a means of presenting a tremendous amount of empirical data in the form of a single curve, it also outlines clearly the problems that face the fundamental investigator. The isothermal transformation curve shows clearly that the phenomena occurring in the neighborhood of the knee of the curve are those that limit the hardenability of steel. Above the knee of the curve, the product of decomposition of austenite is lamellar pearlite and fundamental progress has consisted chiefly of a detailed study of structure and formation of pearlite, largely at the hands of Mehl and his collaborators.'-5 They have shown that formation of pearlite proceeds by a process of nuclea-tion and growth and they measured both the nucleation and growth rate. However, there is still a wide gap between our empirical knowledge and fundamental knowledge, owing largely to the fact that there is no satisfactory theory of nucleation rate or of growth rate. This paper is being written in an attempt to Hl in a small part of the gap. A method was prcsented recently1' for calculating the velocity of edgewise growth of pearlite using an expression for the carbon concentration that satisfies the diffusion equation. The edgewise velocity of pearlite growth in a plain carbon eu-tectoid steel was calculated, using linear extrapolations of the ferrite and comentite solubilities. While the results are in fairly good agreement with the experimental facts, the calculated velocity of edgewise growth is smaller at 600°C. than G, the radial growth velocity of pearlite nodules, whereas one would expect it to be larger. In this paper the calculation will be repeated using a new extrapolation for the ferrite solubility, which gives better agreement between G and T', the calculated velocity of edgewise growth. A calculation will also be made of the effect of carbon content on velocity of edgewise growth, and the problems of calculating the effects of other alloying elements on growth rates will be discussed. It will be assumed that the mechanism of pearlite growth, established by Mehl and

Jan 1, 1947

By Albert J. McIntosh

With petroleum consumption declining temporarily after V-J day, the oil industry is urged to use this period as a kind of stopgap to rebuild its war-depleted inventories and help cushion the effect of this decline on producers and refiners. Higher inventories should be reestablished, since recent experiences have indicated that, by and large, the present inventories of crude oil are too low even with the tremendous current production available. The following analysis indicates that inventory levels could be built up to about 490,000,000 bbl. by the end of 1947, an increase of about 40,000,000 bbl. over the reported stock estimated for the war's end. If at the end of the war the military have some 20,000,000 bbl. on hand, this inventory will either be resold to the industry or certain demands that have been assumed to be met by industry will be supplied out of these military stocks, which would leave about 20,000,000 bbl. (net) to be built up from current production. For stock rebuilding the industry could use 10,000,000 bbl. of crude plus 10,00,000 bbl. of products, totaling 20,000,000 bbl. If this were spread over a year, this would mean 55,000 bbl. a day. By analyzing the average inventories held in a year with the total quantity of goods handled during the year, the following study and tables indicate how far the inventories should increase in the immediate postwar period. Introduction For the period immediately following V-J day, most of the petroleum economists have forecast a considerable decline in the total consumption of petroleum and its products in the United States. This will be caused by the elimination of most of the military demands and the inability of civilians to immediately replace automobiles, burners, etc., and thus increase their requirements to make up for the military decline. When the automobile industry has been back on full production for two or three years, civilians will be able to consume much larger quantities of gasoline. Delay in the manufacture of new oil burners and the time it takes to construct new homes, adds up to the same story for distillate fuels. In reviewing this outlook, the question has arisen whether the petroleum industry should not use this period of lower consumption as a kind of stopgap to rebuild its war-depleted inveritories and help cushion the effect on producers and refiners of this sudden drop in requirements. Some persons have indicated that hundreds of thousands of barrels a day could be used for this purpose extending over a year or more. Refineries will be in existence, which could run over 5,000,000 bbl. of crude oil a day and crude-oil production might be running 600,000 to 700,000 bbl. a day above the demands now forecast for the period after V-J day. Reasons for. Making Inventories In order to plan intelligently for this period, the petroleum industry should determine the needs for the establishment of higher inventories for crude and petroleum products than have been carried during the war. The reasons for trying to make such a determination are as follows:

Jan 1, 1945

By E. T. Turkdogan, L. S. Darken

Using the quadratic formalism, thermodynamic equations are derived for the composition dependence of the heat and entropy of mixing. The applicability of these equations is confirmed by available experimental data on the activities and heats of mixing for binary metallic systems of Group ZZB elements. In a recent paper arkeen' introduced a quadratic formalism describing the composition dependence of the activity coefficient in the terminal regions of binary metallic solutions. That is, in the terminal region, which may extend to as much as 60 at. pct, the logarithm of the activity coefficient, log y,, of component 2 is a linear function of (1 - N,)' where N2 is the atom fraction of component 2. Similarly, for the other component, log yl is a linear function of (1 - N,)'. A number of iron-base binary liquid alloys were shown to obey this quadratic formalism. arkeen' extended this formalism also to any corner of a ternary system and showed that the activity coefficients of the components 1, 2 and 3 (1 is taken as the solvent) can be represented by quadratic terms involving five parameters, four of the binaries and one for the ternary system. Numerous examples given by arkeen' demonstrated the general applicability of the quadratic formalism to iron-base systems over a wide composition range. In this paper further examples are given of binary liquid systems (Group IIB elements, Zn, Cd, and Hg) and of several solid solutions, again demonstrating the appropriateness of this concept. A further purpose of this paper is to extend the quadratic formalism to the enthalpy and excess entropy of binary metallic solutions and to test the equations so found using available experimental data. QUADRATIC FORMALISM FOR HEATS AND ENTROPIES OF MIXING OF BINARY METALLIC SOLUTIONS The following equations, reproduced from Darken's paper, are for the two terminal regions of binary systems. at infinite dilution and a's are temperature dependent parameters to be determined from the experimental data. Although the quadratic formalism is an assumed representation of the data, Eqs. [I] to [4] are thermo-dynamically consistent with the Gibbs-Duhem relation and satisfy Raoult's and Henry's laws as limiting cases. As pointed out previously,' the following form of the Gibbs-Duhem equation facilitates the integration in general but particularly in regions I and 11, where each of the derivatives is constant. The partial molar enthalpy of solution i, (and i; the value of i, at infinite dilution) are related to the activity coefficients y, and y," by the thermodynamic relation Differentiating Eq. [l ] with respect to 1/T and substituting the above thermodynamic relation gives for region (I) It is reasonable to assume that over a temperature range of experimental interest, the enthalpy of mixing is essentially independent of temperature, implying from Eq. [7] that the derivative da,,/d(l/) is also independent of temperature. On the basis of this argument, the temperature dependence of a has the form where £ and S have the units of enthalpy and entropy respectively; they are characteristic parameters for a terminal region of a binary system, e.g. for region (I), C12, S12 and for region (II), d:,,, S2,. Using this equation gives for dff ,/ d(l/), From Eqs. [7] and [9] an expre_ssion is obtained for the composition dependence of L,. Similar calculations are made for El and the results are summarized below for the two terminal regions. For region (I), The corresponding expressions for the molar heat of solution, AHM, are readily obtained from the above equations for the two terminal regions: For region (I),

Jan 1, 1969

By D. Turnbull, J. H. Hollomon

IN the most general sense, solidification refers to the formation of crystalline material from either a gas or a liquid. However, in this symposium, only the formation of crystals from liquids will be considered. Thus, in our present study the problem of solidification becomes that of determining the mechanism of the transition from a liquid to a crystalline solid, and our particular interest is in the transformation of metals from the liquid to the crystalline state. Metal liquids are seldom composed of only one kind of atom. Often solute atoms are added intentionally to make an alloy, or they may be present accidently because of incomplete purification. Furthermore, there may be small solid particles of various other crystals present in the liquid. Such small crystals may persist if their melting points are higher than any temperature to which the liquid is heated. Prior to solidification, the liquid metal usually is poured from one container to another. The second container, called the mold, usually is at a lower temperature than the container, or the crucible, in which the metal is liquified. The first solid that forms upon contact with the mold generally is of a different composition than the liquid, usually containing fewer foreign atoms or dissolved impurities. Heat is evolved upon solidification and is dissipated through the surroundings. Tree-like crystals, or dendrites, grow from the container walls and branch into the melt, enriching the remaining liquid in impurity atoms. In some alloys the remaining, relatively impure liquid continues to solidify until no liquid remains and the branches of the original crystal are cemented together. In other alloys, particles with a second type of crystal structure appear before solidification is complete. First the nature of the liquid and the solid states will be considered and then the mechanism of the initial formation of crystals from pure and alloy liquids. Later the problem of the growth of these crystals and the complexities of solidification in a mold, where the temperatures are not uniform and the composition of the melt changes continuously, will be discussed. LIQUID AND CRYSTALLINE STATES A liquid is an aggregate of atoms arranged with no apparent regularity (over distances of more than a few atom diameters). Nevertheless, any given atom generally has a definite number of nearest neighbors at definite distances, and thus order may be said to exist over a short range. In a crystal, on the other hand, a regular array of atoms continues for many hundreds or thousands of atom diameters, and a long-range order is apparent. Thus, a crystal having long-range order can be reproduced by linear translations for 10-5 cm or more of some fundamental unit possessing short-range order. A crude illustration of the difference between liquid and crystalline structures can be obtained by comparing the possible arrangements of oranges in a crate. If the oranges are simply dumped into the crate haphazardly until it is filled, the oranges will represent a static model of a liquid.

Jan 1, 1951

By Lewis Reeve

As. part of a program of investigation of the properties of electric arc welds carried out in the laboratories of the A. 0. Smith Corporation, considerable work has been done on the determination of the oxygen, nitrogen and hydrogen content of different types of weld metal, employing for this purpose the so-called "vacuum fusion method." It is the purpose of this paper to describe certain improvements that have been introduced in this method of determining the gas content of metals, with particular references to the steel specimens examined in this investigation. The method and apparatus used at the beginning of the investigation were essentially those of the Bureau of Standards as described by Vacher and Jordan.1 Later a number of changes were introduced which resulted in. more rapid evacuation of the graphite crucibles employed and which enabled larger volumes of gas to be dealt with than could be handled conveniently in the Bureau of Standards equipment. In addition, the analyzing of the gases evolved from a melt in the same apparatus as collected was abandoned in favor of analysis outside the equipment using standard methods of gas analysis. The time required for gas analysis in the apparatus itself, as described by the Bureau of Standards, was found to be considerable, and during this time the rest of the equip-ment was tied up, preventing its use for the analysis of further steel sam-ples. As a result of the modifications introduced, the time required for the analysis of a steel sample for gas content was reduced from about 8 hours to less than 3 hours. Subsequently, the whole procedure of melting the sample and collect-ing the gases evolved was modified so as to enable a distinction to be drawn between the easily reducible oxides such as iron oxide and the more stable oxides such as silica and alumina. At the same time evidence was obtained indicating the probable existence in the steels of other nitrides than those of iron alone and making possible their quantitative determination.

Jan 1, 1933

By D. L. Gardner, H. L. Barr

The following report covers the history of the development of the mine, present equipment, methods and costs of mining and milling. In addition, a description of the ore deposit is given with emphasis on the origin of the fractures, mode and types of ore occurrence, and mechanics of granite emplacement. An endeavor has been made to present a complete and accurate statement of the San Mauricio mine, the highest grade gold mine in the Philippine Islands. Credit is gratefully acknowledged to the mine staff for descriptions and details regarding their particular field of work. All analyses were made by Mr. T. A. DeVore, head chemist, San Mauricio Mining Co. Messrs. Edward Wisser, J. E. Fyfe, A. F. Skerl and W. B. Meek, geologists, have contributed geologic information and ideas, for which thanks are extended. The Executive Committee of Marsman and Co., Inc., Managers of the Company, has kindly given permission for publication. Mr. J. B. Stapler, Division Manager, Marsman and Co., has had the courtesy to read the manuscript and to give critical and helpful suggestions. Location of Area and Scope of Work San Mauricio Mining Co. controls a group of 113 claims that lie immediately north of the town of José Pafiganiban (formerly Mambulao), Camarines Norte, Luzon, P. I. (Fig. 1). Exploration work commenced in the spring of 1934; active development began in the fall of that year and has continued to the present date. Mill construction was begun Ocl,. 15, 1935, and production started March 10, 1936. Total production to June 1, 1939, is P10,499,105.15 ($5,249,552.57).

Jan 1, 1941

By H. A. Baumann, A. J. Rostosky

EVER since the first installation of wet-washing methods of coal preparation, the removal of the water added by the washing process has created serious technical and operating problems. The rapid development and widespread adoption of wet washing has necessitated a corresponding development of dewatering methods and equipment. The amount of water retained by coal varies with the size of the coal. The moisture that is largely on the surface of the particles is easily shaken off coarse coal; thus coarse coal can be dried comparatively easily and quickly. Fine coal presents a larger surface area than does coarse coal, so its capacity for retaining moisture is greater. In fine coal, moisture below about 5 per cent is held between the coal particles and its removal is difficult. Draining and drying of the finer sizes is a major problem at many washeries. Two common problems of coal-washing practice that are intimately connected with dewatering and drying are the clarification of washery water and the prevention of stream pollution. The first field has been studied from many angles, including the use of coagulating and settling agents followed by vacuum filters to remove the solids, and the use of sludge tanks with dewatering screens incorporated therein. In many districts, the disposal of sludges into streams has been stopped by law. The lack of space for impounding sludges has created problems of disposal in other districts. Reduction in moisture means a saving in freight costs as well as the elimination of difficulties in unloading and storing. Excess moisture in coal causes it to freeze in localities where severe climatic conditions prevail. Excess water in coals to be used in the production of coke and manufactured gas has a chilling effect on the walls of the oven or retort. Dryness of coal is important in producing good briquettes. CLASSIFICATION OF MOISTURE Moisture in coal can be classified as inherent and surface moisture. Inherent moisture is regarded as a part of the true coal substance, having been present in the original vegetal matter from which coal was

Jan 1, 1943

By Max Y. Seaton

THE scope of this paper will be limited to finished materials that contain a large preponderance (around 80 per cent or more) of magnesium oxide. The large and commercially important production of refractory dolomite and modified dolomites is not discussed here, and the production of magnesium basic carbonate for use as a heat insulator is barely mentioned. The discussion is confined mainly to magnesias produced in comparatively great quantity by direct processing of naturally occurring raw materials and hence excludes secondary or highly purified products such as pharmaceutical products or U.S.P. light and heavy calcined magnesias of commerce. NOMENCLATURE The nomenclature of the magnesia products that will be discussed is somewhat confusing, in that it is customary in the trade to designate as "calcined magnesite" the materials that result from the calcining of magnesite to temperatures that remove the contained carbon dioxide. The finished product, therefore, is not magnesite at all but simply a more or less pure magnesium oxide or magnesia. Furthermore, partly for statistical and partly for commercial reasons, it has been customary, during recent years, to classify as "calcined magnesite" products that result from the heat-treatment of magnesium hydroxide precipitated from magnesium-containing brines; products that, obviously, have no relationship whatever to magnesite. In the listing of magnesia-containing materials, tonnages of which are regularly reported by the Bureau of Mines, reports ordinarily are made under two headings: "caustic calcined" magnesite, in which all of the varieties of products treated at relatively low temperatures are lumped; and "dead-burned" magnesite, in which are included both high-purity and low-purity, and particularly both high-iron and low-iron, materials that have been so heat-treated that the magnesium oxide occurs predominantly as crystalline periclase-materials used almost entirely for refractory purposes. In 1940 the apparent domestic consumption of "caustic calcined" magnesite was approximately 17,000 tons, about 95 per cent of which was produced in this country. The apparent consumption of "dead-burned" magnesite was approximately 172,000 tons, some 82 per cent of which was domestically produced. In both total quantity and percentage of material produced within the United States, these figures are record highs for many years past. UTILIZATION As indicated by these figures, the major tonnage outlet for magnesia is the refractories industry, in which magnesia is employed principally in three ways: (I) as dead-burned grain magnesite for the construction and maintenance of the hearths or bottoms of basic open-hearth furnaces; (2) in the form of refractory magnesite bricks and shapes; and (3) as a chemical

Jan 1, 1942

By S. Dinda

A series of as -quenched 4340 bars were drawn through a carbide die to various reductions. The X-ray diffraction technique of Lopata and Kula was employed to detect preferred orientation in drawn martensitic steel bars with low amounts of deformation, as lord as 0.8 pct The specimen face of each bar examined was cut at a 45-deg angle to the bar axis. The reflecting planes in the 45-deg face were varied by appropriate rotation of the sample using a spectrogonionzeter. TIE X-ray bean of a diffractometer was reflected from the center of the bar and the diffracted intensity was delected with a proportional counter and recorded. Intensity peaks were developed by cold working for 110 planes oriented at 0 and 60 deg to the bar axis. The intensity peaks increased with increasing defortnalion us a preferred orientation with a 110 texture developed parallel to the drawing direction. The intensity peaks for deformed as-quenched specimens remain unchanged after tempering at temperatures as high as 1000°F. The same amount of preferred orienlalion was observed both inferritic (hot-rolled) and martensitic (as-quenched) structures after an equivalent amount of deformation. THE deformation of martensite with medium carbon content. less than 0.5 pct, has been studied by Breyer et a1.1,2 It was reported that changes in properties such as resistivity, carbide precipitation, and the introduction of a yield point phenomenon were produced after cold reduction of as-quenched AISI 4340 steel bars. Later, Breyer and Nachtman3 studied the effect of cold reduction upon X-ray line intensity. They showed that the integrated 110 line intensity increased with increasing deformation when the planes examined were perpendicular to the die drawing direction. The integrated 110 line intensity for planes oriented at 45 deg to the die drawing direction, in contrast, were found to slightly decrease. These changes were proposed to be consistent with the previously proposed model of a stress-induced ordering of carbon atoms in the vicinity of dislocations.1,2 Objections can be raised to the above interpretation of the X-ray results on two grounds: a) Rough structure factor calculations indicate that the intensity changes are too large (50 pct observed vs 2 pct calculated4,5) to be the result of changes in the location of iron atoms produced by the stress-induced ordering of the carbon atoms. b) The results might be explained in terms of preferred orientations, although X-ray evidence of the development of texture has not been reported in the literature for deformations as slight as 1 or 2 pct. The aim of the present work was to determine if preferred orientation was present in such cold-drawn martensitic steel bars. In drawn rod or wire there is generally a certain crystallographic direction which is aligned in the direction of the wire axis, and the crystallographic planes are distributed symmetrically around this "fiber axis".6-8 This type of cylindrical specimen, with the fiber axis located at the center, will show rotational symmetry. Lopata and Kula9 proposed an experimental method utilizing a specimen cut at 45 deg, see Fig. 1. The X-ray beam is diffracted from the center of this bar cross section. The specimen is rotated around an axis perpendicular to the bar axis and lying in the 45-deg cut face. This permits the angle between the normals to the reflecting planes and the bar axis to be varied from 0 to 90 deg.9 With this arrangement the errors due to absorption and irradiated volume compensate each other.' This greatly simplifies analysis of the data and is of considerable advantage for quantitative measurements. If there is preferred orientation in the specimen, more planes are oriented in a particular direction in the bar. When the bar is rotated to the favorable Bragg condition for that particular orientation, the intensity will be higher than that for some other angle. This technique was adopted for the present investigation.

Jan 1, 1969

By Edwards Wichers

The purpose of this paper is to set forth the matters of principal interest in connection with work done in the past few years on the purification of the metals of the platinum group, including the study and modification of methods already in the literature and the development of new procedures. For the most part, the results will be given in summary form, reserving the publication of detailed data and directions for a forthcorning paper to be issued by the Bureau of Standards. In recent years increasing interest has been shown in the preparation of the pure platinum metals, both by those concerned with the manufacture of the metals and their alloys for scientific and industrial purposes and those who are engaged in the study of the chemical or physical properties of the elements. The purification of the metals usually has been regarded as a matter so involved and difficult as to require the attention of specialists. It is hoped that this paper will show that any of the metals can be prepared in any desired degree of purity by relatively simple straightforward chemical methods. For the most part, it is thought that the methods given are suitable for small-scale refineries as well as for the laboratory; also, that they will bring the time required for the purification of any of the metals within reasonable limits. The new procedure suggested for purifying platinum should prove to be much shorter than any methods described in the literature. Treatment of Platinum Ore As is well known, the principal source of the platinum metals is a mixture of several native alloys of the metals, found chiefly in naturally concentrated deposits in stream beds or alluvial material. Without attempting to enumerate all of the minerals present, it may be said that the concentrated ore from such sources contains all of the six platinum

Jan 1, 1928