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By B. P. Mulcahy

When the phrase "selection of coal for carbonization" is used, there is always the implied continuance of thought "to make good coke.'' The reason for this, of course, lies in the fact that, in almost all instances, when coal is carbonized coke is the principal product. Under certain conditions the yield of gas may also be a factor, but even here it must be secondary to the coke yield, for in every instance coke represents the largest single product of the process. The importance of coke to the byproduct industry has been considerably enhanced during the past 20 years because of the continuously decreasing financial returns of all the by-products. This fact will account, in part, for the rebirth of interest and investigation in the carbonization process during the past 10 years. Many papers have been written on this subject, with naturally divergent thoughts because of the diversity of interests, but in each instance the common aim was the same—the making of better coke. Scope of Investigation In perusing this literature, the writer was struck with the constantly recurring imposed condition of asking for better coke, but with the distinct unwillingness to make any concession to temperature of carbonization. When there is a high demand for coke, the only means by which the industry can increase the quantity is to shorten the coking time by an increase in temperature, or to increase the quantity of low-volatile coal, or both; and since in many instances the percentage of low-volatile coal can be increased only in small quantities, because of factors to be discussed later, the big increase must come from shortening the coking time. When this is done most of the improvement accomplished by the selection of the coals in the mixture is lost. It is not felt necessary in this paper to discuss the advantages of minimum ash and sulphur and other materials in coal. The value of minimum contents of these materials in coke is well established. When the use of coals high in these contents is dictated, the selection of coals, as we will consider it here, cannot apply to full advantage. The scope of this paper, then, will be to discuss the factors of inherent coal characteristics and operating procedures that influence coke quality, for they are fundamentally related and both must be considered if we are to attain our objective of better coke. A study of either must embrace a study of both simultaneously. To properly evaluate the influence of the coal and to help in the selection, we must first be able to appraise the coke, and interpret fairly the influence of the process in all of its aspects. Appraisal of Coke To refer simply to the quality of coke gives no indication of what is meant, for the term is too general in its implication. An analysis of a coke is divided usually

Jan 1, 1944

By B. P. Mulcahy

When the phrase "selection of coal for carbonization" is used, there is always the implied continuance of thought "to make good coke.'' The reason for this, of course, lies in the fact that, in almost all instances, when coal is carbonized coke is the principal product. Under certain conditions the yield of gas may also be a factor, but even here it must be secondary to the coke yield, for in every instance coke represents the largest single product of the process. The importance of coke to the byproduct industry has been considerably enhanced during the past 20 years because of the continuously decreasing financial returns of all the by-products. This fact will account, in part, for the rebirth of interest and investigation in the carbonization process during the past 10 years. Many papers have been written on this subject, with naturally divergent thoughts because of the diversity of interests, but in each instance the common aim was the same—the making of better coke. Scope of Investigation In perusing this literature, the writer was struck with the constantly recurring imposed condition of asking for better coke, but with the distinct unwillingness to make any concession to temperature of carbonization. When there is a high demand for coke, the only means by which the industry can increase the quantity is to shorten the coking time by an increase in temperature, or to increase the quantity of low-volatile coal, or both; and since in many instances the percentage of low-volatile coal can be increased only in small quantities, because of factors to be discussed later, the big increase must come from shortening the coking time. When this is done most of the improvement accomplished by the selection of the coals in the mixture is lost. It is not felt necessary in this paper to discuss the advantages of minimum ash and sulphur and other materials in coal. The value of minimum contents of these materials in coke is well established. When the use of coals high in these contents is dictated, the selection of coals, as we will consider it here, cannot apply to full advantage. The scope of this paper, then, will be to discuss the factors of inherent coal characteristics and operating procedures that influence coke quality, for they are fundamentally related and both must be considered if we are to attain our objective of better coke. A study of either must embrace a study of both simultaneously. To properly evaluate the influence of the coal and to help in the selection, we must first be able to appraise the coke, and interpret fairly the influence of the process in all of its aspects. Appraisal of Coke To refer simply to the quality of coke gives no indication of what is meant, for the term is too general in its implication. An analysis of a coke is divided usually

Jan 1, 1944

By E. F. Johnson, F. H. Brinkman, H. J. Welge, A. L. Hicks

A method is presented for predicting the character of gas or water displacement in a radial system, which can be either horizontal or inclined. The latter case would comprise cone-shaped or dome-shaped symmetry. The method conriders the one dimension of radial distance, taken parallel to the bedding planes. Approximate allowance can be made for segregation of the two fluids perpendicular to the bedding planes. A complete saturation history can be obtained in about a day's time with the use of a desk calculator. Results of an example calculation agree well with the performance of simulated gas drive in a large model representing a section of a cone. This pie-shaped, sand-packed model was 8-ft long and 4-in. thick. The method of solution is useful in handling other partial differential equations of first order and first degree. INTRODUCTION A new analytical method has been developed for predicting the performance of gas or water drive in a reservoir having radial or cone-shaped symmetry (see Fig. 1). In addition, this new development offers a general method of handling partial differential equations of first order and first degree. This work extends those methods developed previously'- "or predicting the displacement of oil by gas or water in linear systems. The method of calculating oil recovery in a radial system involves two major parts. The first part is a calculation of the distribution of saturations at various times of depletion. The second part is the calculation of oil recovery and producing gas-oil or water-oil ratios through volumetric balance on the saturation distributions obtained in the first part. This second part differs only slightly in principle from similar calculations made with linear systems, for instance. The basic assumptions used in the calculations are as follows. 1. One-dimensional radial flow. An approach is explained later for approximating a second vertical dimension. (With- drawals of oil, and of the driving fluid after breakthrough, are assumed uniform around the periphery of the dome.) 2. Constant-volume fluid flow. Thus, in a gas drive there is no change in gas solubility, or in oil or gas volume due to viscous and gravity pressure drops. 3. Capillary forces are negligible. 4. Constant rate of injection. A program has been written for carrying out the calculations needed on a digital computer. However, a prediction can also be arrived at using a desk calculator; this latter method of work requires about a day's time for each prediction made. CALCULATION OF SATURATION DISTRIBUTION For definiteness, we describe the development of our method for the case of gas drive from the crest of the structure. The reader will note, however, that the method is just as applicable to an advancing radial water drive. The equation describing gas flow over an infinitesimal

Page Bronze Bearing Metals. By G. H. Clamer............... 162 Pennsylvania Railroad Anti-friction and Bell Metals. By F. M. Waring .. 166 The Tin-plate Industry. By D. M. BUck. Discussed by G. H. ClameR, J. W. RICHARDS............................ 168 The Aluminum Bronze Industry. By W. M. Corse............ 171 Bronzes, Bearing Metals, and Solders. By G. K. BURgess and R. W. Woodward. Discussed by G. H. Clamer, R. T. Roberts......... 175 Babbitts and Solder. By G. W. Thompson................ 184 The Cadmium Supply of the United States. By C. E. Siebenthal. Discussed by M. L. Lissberger, C. W. Hill, F. F. ColcoRd.......... 185 Solder, Its Use and Abuse. By M. L. LissbergeR............ 192 Bronze Bearing Metals G. H. ClameR,* Philadelphia, Pa.—Unfortunately, prior to the war no serious attention was given to the conservation of tin, notwithstanding that this country is practically dependent upon outside sources for its entire tin supply. Tin is of vital importance in many industries, but it is surprising how many and how excellent are its substitutes when we become acquainted with them. Tin has always been a relatively high-priced metal, and it is part of the human attitude to associate high prices with high standards; it is not until the price of a commodity becomes well-nigh prohibitive that we hunt for substitutes, because the idea of substitution seems always to involve an assumption that the substitute must necessarily be inferior. The history of the development of bearing bronzes is a striking example of this policy. In the early days, copper-tin alloys were almost universally used, the idea then being prevalent, which is still held by many, that a bearing to resist wear must be hard, and the harder the better. The favorite bronze bearing contained 90 per cent. copper and 10 per cent. tin; frequently, in service which was considered severe, even higher proportions of tin were used. Such hard alloys have great resistance to compression, but as a rule they had a very wide factor of safety in this

Jan 1, 1919

By H. M. Fisher, R. E. Snow, S. C. Sun

RAPID colorimetric estimation of the amount of transparent minerals has been applied successfully to instream mill products at the cryolite flotation plant of the Pennsylvania Salt Mfg. Co., Na-trona, Pa. Apparatus used was a Bausch & Lomb monochromatic colorimeter. The optical assembly of the colorimeter, shown in Fig. 1, passes light from a 6-v, 32-cp, prefocus incandescent lamp through two condensing lenses, a heat-absorbing filter, an aperture-control diaphragm, an interference filter, and a sample container. The light finally strikes a barrier-layer photocell and the output current of the photocell is measured by a galvanometer. The engraved index line of the collective lens, located between the lamp and the galvanometer, is imaged upon the transmission scale of the colorimeter by the galvanometer mirror. Reflected light from the galvanometer mirror, the position of which is determined by the output current of the photocell, enables reading of percent transmission throughout the mineral sample being tested. The colorimeter, Fig. 1, was standardized as follows: 1—The colorimeter was' connected to a Sola constant voltage transformer, A, of 6-v output operated from a 110-v ac supply. 2—Turning the toggle switch, C, illuminated the transmission scale, B, and the control knob, D, was adjusted with a blank in the optical system until the hairline on the scale read zero. 3—A No. 430 interference filter, E, was inserted into the filter channel, F. 4—A test tube, G, containing 7 cc of distilled water was pressed into the sample space, H, and the fine adjustment knob,

Jan 1, 1955

By Thomas L. Watson

MY thanks are due to Mr. Frank Firmstone, Easton, Pa., who has called my attention to the statement in my papers that " Barite, fluorite and quartz, though not observed in the Tennessee area," . . . as possibly misleading to the reader, if construed to mean that such a discovery had never been made. Mr. Firmstone is correct in assuming that this statement referred only to the study of the worked areas of the metallic ores, especially zinc, made in the course of the survey upon which my paper was based. The occurrence of barite and fluorite with lead-ores in Tennessee was reported by Prof. Safford,2 in 1869, and by Safford and Killebrew,3 in 1887, with the further statement that about 1,000,000 lb. of barite were annually mined in Greene, Washington and Jefferson counties, Tenn., and that considerable deposits occur also in McMinn, Smith and other counties. It is also noted that the barite ".usually occurs in veins, associated with galena." The present worked areas of barite are, however, distinct barite propositions, without workable quantities of either lead or zinc, so far as mining operations have gone, and the areas are more or less removed from the present areas of zinc-ores. Mr. Firmstone informs me also that, in 1892, he observed, in the magnesian limestone at Watauga Point, in Carter county, on the left bank of the Watauga river, a little below the mouth of Buffalo creek, small quantities of galena and some fluorite.

Jan 1, 1907

JOINT convention week has become a feature of the year with western mining men. The first was held at Denver in 1926, the second at Salt Lake City in 1927, and the third is about to take place at Los Angeles. Holding in the same city in one week the meetings of a number of related organizations has been .found to permit the development of a well-rounded program at the same time that it economizes time and money for the members, many of whom belong to several of the participating organizations. For the third time, the American Mining Congress, represented by its Western Division, of which Philip Wiseman is chairman, is taking the lead and assuming the main responsibility. The A.I.M.E. is furnishing the papers for two sessions and the California Development Association for one. The Southern California Section, Robert R. Boyd, chairman, is host for the Institute, but the Northern California, Nevada and Arizona sections have each contributed papers to the program, and will be represented at the meeting. It will be a real reunion of the mining men of the Southwest.

Sep 1, 1928

By F. H. Wilson, M. L. Kronberg

The low temperature recrystalliza-tion of very heavily rolled copper produces a fine grained structure with a high degree of preferred orientation. Additional heating to within a few hundred degrees of the melting point may induce an abrupt and pronounced increase in the grain size, with the resulting crystals having new orientations. This behavior at high temperatures is commonly termed "secondary recrystallization." Several investigations have dealt with the phenomenon arid have served to bare many features of the beha~ior.1-4 In general,observations have been made on the sizes and shapes of the grains, and data have been presented showing the existence of an induction period in isothermal experiments. Although it has been well established that the orientation before the change is statistically (100) 10011, the so-called "cubically aligned" texture, there is no such agreement on the orientation after the change. For example, Dahl and Pawlek1 describe it as being equivalent to an approximately 30" rotation about the [l00] axis of the ideal cubic texture which is parallel to the rolling direction, the resulting orientation being near (210)[001]; and Cook and Richards2 find an orientation of approximately (110)[L12]. Since the completion of most of the work to be reported in this paper, Rowles and Boas3 have published their ver] illuminating paper on "secondary recrystallization," in which they present convincing evidence for a third orientation and show that their esperiments give no evidence for either of the other two orientations. The orientation is described as equivalent to an approximately 30° rotation about a [ 111] pole of the ideal cubic orientation. The existence of a variety of reported orientations is not unique for copper, for a similar state of affairs exists for other systems that have been studied— aluminum, nickel, nickel-iron alloys, and others. It seems therefore that the existence of this variety does not necessarily constitute a contradiction, but rather indicates that different experimental conditions yield different results. The fundamental nature of the phenomenon has not been elucidated. However, it has been generally recognized that the large grains could be the end product of growth of a few select grains already existing in the sample in minor amounts—too small to allow detection—or that entirely new ones could be formed by a process of nu-cleation and growth. Existing experimental evidence does not distinguish between these two most apparent possibilities. Nevertheless, the former has been more generally favored largely because our current understanding of the state of an annealed metal has not made it seem reasonable to expect a nucleation event to occur at temperatures above those required for the primary recrystallization. Observations on the Preparation and Heating of Twin-bearing Cubically Aligned Copper The starting material used throughout. the investigation was a bar of OFHC copper, forged and annealed at 950°C. Visual inspection showed the grain size to be around 0.5 mm, and did not disclose any preferred orientation. A chemical analysis showed the following composition: Cu + Ag— 99.99 Pct S — 0.005 pct 0 — <0.005 pct For the preparation of cubically aligned copper, ¾ in. thick slabs were cut from the bar, heavily pickled in concentrated HNO3 and cold rolled to sheets about 0.012 in. thick. The reduction in thickness was approximately 98.5 pct. Standardized annealing techniques were followed. Samples to be heated were lightly dusted with alumina in order to prevent sticking and then sandwiched between 1/16 in. copper plates. The resulting sandwich was heavily wrapped with copper sheet, and then annealed in air. The protection was such that only very thin films of oxide were formed. That the associated light oxidation of the samples had no specific effect on the recrystallization behavior was shown by the similar results that could be obtained on annealing in highly purified and dried hydrogen. Two methods were used in bringing samples to temperature: (1) by placing the package directly in the furnace at temperature and (2) by placing the package in the furnace at room temperature, and then slowly increasing the temperature. The corresponding heating rates are illustrated in Fig 1, and will be referred to as "rapid" and "slow," respectively. Unless specified otherwise, all anneals will be of the former type. Metallographic examination was made on samples prepared by electrolytic polishing and etching as described in the Metals Handhook.* STRUCTURES FOUND BEFORE "SECONDARY RECRYSTALLIZATION" OCCURS Annealing the rolled material for 1 hr at 400°C produced a heavily twinned, cubically aligned structure, the grain size being of the order of 0.03

Jan 1, 1950

By Charles White Merrill

Mankind&apos;s progress is measured in minerals. Man&apos;s emergence from prehistory is marked by passage through a Stone Age and a Bronze Age and into the present era, sometimes called the Iron Age or the Age of Metals. With the evolution of civilization and the development of a modem industrial economy, minerals become more and more important. Structures, roads, and machines are built largely of minerals; the energy to heat the structures and to drive the machines is mostly mineral; agricultural fertility is maintained by mineral fertilizers and water; and military strength is provided by fortresses, armaments, and munitions, largely of mineral origin. Thus in the material world, in the productivity of the economy, access to minerals has paramount importance. Every evidence indicates increasing dependence on minerals in the modem economy, particularly on the mineral fuels as energy sources to provide the power base for advancing industrialization. Both the total and the per capita consumption of almost every mineral is increasing in the industrialized nations. Moreover, nations with predominantly agrarian economies call themselves underdeveloped and universally strive to industrialize. Most mineral consumption trends in the more advanced economies have been greatly exceeding population growth-which itself has been advancing at an accelerating rate-and sometimes have surpassed the growth in real income. Some minerals have only recently been adopted or grown to importance in use. Titanium metal did not appear as a commercial product until 1948, and even coal seriously displaced wood as a source of heat less than two centuries ago. On the other hand, minerals have always played an important role in construction. The prehistoric megaliths that form the dolmens of Salisbury Plain are stone; the pyramids are andesite faced with limestone; and many other ancient structures are built of mineral materials. In modem times the whole course of architecture has been redirected by new building materials, mostly mineral. Most conspicuous is the sky-

Jan 1, 1964

By C. M. Schwartz, A. E. Austin, W. B. Wilson

High-temperature X-ray diffraction studies were conducted with Th-U alloys with up to 10 wt pet U. The solid solubility of uranium in thorium as a function of temperature was determined by the method of lattice parameters. Thorium will dissolve up to 2.5 wt pet U at 950°, 4.5 wt pet U at 1150°, and 7.5 wt pet U at 1250°C. Determinations were made of the temperature of the transition of thorium and of the effect of uranium upon the transition. The a to ß transition for thorium was observed to occur at 1330&apos; ±20°C. Mean coefficients of expansion were calculated for thorium and two alloys, and for ThO2 in contact with the thorium, using X-ray lattice-parameter data. Values obtained at 950° C for thorium and Tho2 were 12.1 and 9.40 X 10-6 per OC, respectively. Impurities obtained during the X-ray exposure were identified by diffraction and were essentially Tho2 and ThC, with two additional unknown phases being detected. The effect of the impurities upon the results is discussed. DIRECT investigation (i.e., high-temperature X-ray diffraction studies) of the phase diagram of thorium-rich uranium alloys has been shown to be necessary since recent work1 - has disclosed the presence of an allotropic transformation near 1400°C in pure thorium with the room temperature face-centered-cubic phase transforming to a body-cen-tered-cubic structure at the elevated temperature. The effect upon the transition of the addition of uranium to thorium and of the solubility of uranium in thorium at high temperatures remained unknown, yet was of interest in understanding fabrication procedures and elevated temperature use. The present work was undertaken to provide information in this area by determining the transition temperature, the effect of uranium on the transition temperature, and the solubility of uranium in thorium as a function of temperature. Experimental Work The high-temperature diffraction data were obtained using a camera especially designed for the purpose3 and capable of reaching temperatures in excess of 2000°C at pressures as low as 1 x 10." mm Hg. Temperature regulation was provided by regulating the power input to ±0.1 pet variation, and by regulating the water flow through the camera jacket to provide a constant thermal load. The X-ray sample was a rod nominally 80 mil diam, which was further turned down to 20 mil and then etched to 18 mil over 1/2 in. of one end. This was placed in the sample holder and mounted on the camera so that the smaller part was surrounded by a cylindrical tantalum-sheet radiation-type heating element. Diffraction from the sample was recorded on film after passing through a slot in the heating element and radiation-baffle shield and through beryllium vacuum windows. The X-ray film mounting was of the Straumanis type4 with a camera diameter of 114.59 mm. Since previous work of Chiotti&apos; indicated that impurities considerably alter the transition temperature, chemical analysis of the arc melted iodide crystal-bar thorium samples was obtained prior to testing. The analysis disclosed the material to contain as low as 0.001 ±0,0002 wt pet H and 0.007 ±0.001 wt pet 0. Carbon was 0.003 wt pet and nitrogen less than 0.002 wt pet. This material was sealed in mild steel in an inert atmosphere and subsequently hot rolled to 3/8-in. diam rods at a temperature of 732°C. Following removal of the jacket, the material was pickled and cold swaged to 1/8-in. rods, from which the diffraction samples were prepared. The alloys were similarly prepared, with the uranium being added during arc melting. The uranium analyses of the alloys prepared appear in Table I. The experimental procedure for diffraction examination of the three samples of high-purity thorium differed from those of the Th-U alloys. The original practice, later modified, consisted of pumping down the camera with the diffusion pump on and then admitting liquid nitrogen to the cold trap of the system. This was modified for the Th-U alloys by maintaining liquid nitrogen in the cold trap at all times before and while the diffusion pump was heated. This minor change produced a reduction in the amount of carbon pickup by the sample during exposure to the diffusion-pump vapors. The sample was brought to the desired test temperature and exposed for 21/2 hr at pressures which were usually 2 x 10-6 mm Hg, or lower. Exposures were made at

Jan 1, 1959

By Louis V. Bender

THIS paper gives a short review of the installation for and the use of gas, as a. fuel, at the Anaconda Reduction Works of the Anaconda Copper Mining Co. Before putting in gas tile fuels used were pulverized coal, lump coal, coke distillate and oil. These fuels are now almost entirely eliminated. For nearly fifty years bituminous coals from Wyoming and Montana fields had been used. These coals were of a good grade, analyzing 11,300 B.t.u. and having an ash content of 12 per cent. When hydro-electric power replaced steam-driven equipment, the coal requirements were reduced; and, on account of improvements in metallurgy and/ or in furnace design, the quantity was lessened. Later, oil and distillate were introduced and used in some of the operations. All of these things tended toward the lessening of the amount of coal used, and had it not been for the increase in the size of the plant, the tonnage used would have been small when the change was made to gas.

Jan 1, 1932

EDWARD W. PARKER,* Philadelphia, Pa. (written discussion ?).-The two papers on coal-mine costs and pride fixing that Mr. Norris has contributed to the Transactions possess as much general interest and are of as much value to the coal-mining industry as any papers that have been presented in recent years. Until recently one of the troubles with the coal business, and especially the bituminous branch of it, has been that because of the lack of a uniform system of cost accounting (many operators, I regret to say, not having had any system at all), the industry as a whole may be said not to have known where it was at. The system adopted by the Federal Trade Commission may not be absolutely perfect but it has accomplished something in that it has compelled a uniform method of reporting and tabulating costs giving results of these compilations which are comparable. The Institute and the coal-mining industry owe a vote of thanks to, and of confidence in, Mr. Norris and his two associates on the Engineers Committee of the Fuel Administration, Messrs. Garnsey and Allport, for the great work they have done in interpreting the results compiled by the Federal Trade Commission, not to speak of the personal sacrifices made by them in giving their services to the government. Those who have read Mr. Norris&apos; paper will probably join me in wishing he had brought out a little more fully the real meaning of the charts so far as they indicate the difference between the cost of producing a ton of anthracite and the price the operators receive for their product. Mr. Norris could have done this more satisfactorily than anyone else. It seems to me that particular attention should be drawn to the fact that, according to these charts, and the tables accompanying them, not less than 25 per cent. of the total output of anthracite, whether "company" or "individual," during the period covered by Mr. Norris&apos; paper,

Jan 4, 1919

By Henry F. Hebley

INTRODUCTION How often has the thoughtful observer pondered the apparent contradictions experienced in the weather? One can take records of two days, one in the winter and one in the summer. The "degree days" indicate that space heating and domestic load were present in one case and not in the other. The Business Index may be about the same, indicating that the industrial activity of the area and its concomitant use of fuel were about the same. Thus the volume of the products of combustion released to the atmosphere varied only as related to the space heating demand. Yet on one day in winter the atmosphere may be clear and bracing, while on a summer&apos;s day the air is thick and murky and the visibility sharply reduced. The situation may be reversed. What are some of the factors that contribute to the creation of these conditions? These few notes have been prepared to indicate some of the influences that are exerted on the problem. THE SOURCES OF ATMOSPHERIC POLLUTION The industrial area of Pittsburgh, Pa., has been a dominant center for the production of iron and steel for over one hundred years. In fact, with the growth of the numerous auxiliary processes Allegheny County which contains Pittsburgh is probably the most industrialized county in the world. In addition, the type of manufacture carried out in this area is predominant dependent on thermal energy (heat). That energy is supplied from coke and coal produced in the vicinity of Pittsburgh. Indicative of the stupendous quantities of fuel that are employed in this industrial area&apos;s economy, the following (Table No. taken from the U. S. Census (1940) may I of interest. An influence that has never been fully appreciated by many individuals is the fact that no matter what adventures the gases of combustion experience as they pass through the various processes, ulti¬mately the spent gases are discharged through chimneys to the atmosphere.

Jan 1, 1948

By Frank Rieber

THE study of earthquakes long ago developed the fact that by studying the travel times of the various groups of waves from the same earthquake, as received on seismographs at varying distances, major discon-tinuities in the earth&apos;s crust could be reasonably well defined. Using this original discovery, and adapting the mathematical methods originally devised in seis-mology for determining the depth below the surface at which such discontinuities occur, other investigators were able to develop a new branch of seismology which promises to be extremely useful in extending the boun-daries of our information oil local conditions below the earth&apos;s surface. As an outstanding example of the applications of this work, we have the so-called "seismo-graph" exploration of the Gulf Coastal region, which has resulted in the discovery of a large number of salt domes, from many of which oil fields may be developed. The original seismological investigations, from which different major discontinuities in the earth&apos;s crust were deduced, as well as these later successful experiments in finding salt-dome structures, involve relatively simple problems. In each case we are dealing with surface materials in which elastic waves will be propagated with a fairly definite velocity. Under this material we have something very different, in which the elastic waves will be propagated with a much higher velocity. The transition from one medium to another is like-wise relatively abrupt. For example, in. the Gulf Coastal region the sedimentary formations have a velocity of 6000 or 7000 ft. per sec., while the velocity of elastic waves in the cap rock of a salt dome" may exceed 15,000 ft. per sec. Under such conditions, de-lineation of the formation is a relatively simple matter, and, furthermore, there is very little opportunity for ambiguous results.

Jan 9, 1928

By Arthur F. Taggart

THIS paper proposes two units (believed to be new) for designating, respectively, capacity and efficiency for primary and intermediate crushers. CAPACITY Operators know that the tonnage of rock that can be put through a particular crusher in a given time depends primarily upon the crusher setting (open setting for jaw and primary gyratory types; closed setting for cones and rolls), and secondarily on the lithological character of the feed, its maximum size, the amount of fines that it carries, its moisture content, and the method of feeding. The proposed capacity formula states a relationship between all of these factors in one empirical equation, as follows: TR = TR80KK&apos;K" [I] in which TR, called "reduction tons per hour" is the new capacity unit; T = tons of feed per hour requiring crushing; R50 = "80-per cent reduction ratio"; and K, K&apos;, and K" are constants that approximate quantitatively lithological character, moisture content and method of feeding, respectively. T is the hourly weight of material in the feed that is coarser than the coarsest discharge of the crusher. (For marked departures from the normal specific-gravity range-2.5 to 2.7-T should be adjusted to corresponding volumes.) In the crushers under consideration, discharge from the crushing zone is limited by the minimum dimension of a particle. Passage of the particle through a square-mesh screen is limited by its intermediate dimension. Sheppard&apos; has shown that the ratio of maximum: intermediate: minimum average dimensions of broken rock fragments may be taken as about I.5: I: 0.6 for nonslabby rocks such as are normally crushed, while for slabby rocks, such as thin-bedded sedimentaries, foliated schists and gneisses, and the blocky metamorphics, the ratio is of the average order I.3:I:0.3, with the possibility of an even smaller relative value for the thickness. Gaudin2 finds the corresponding ratio for -150 + 200-mesh pyrite to be I.4: I : 0.6. The hourly tonnage of crusher-plant feed, therefore, should be diminished by the amount thereof that would pass a square-mesh screen of which the aperture is S times the crusher setting, where S is a shape factor with the value I.7 for rocks that break exceptionally cubic; 2 for ores and rocks that exhibit no appreciable tendency to slabbiness; and 2.5 to 3, or, in exceptional cases, even larger, when the tendency to slabbiness is marked. R80 is the quotient of the theoretical square-mesh aperture that would pass 8o per cent of the feed, divided by the aperture that would pass S0 per cent of the product. It is best determined from screen tests.

Jan 1, 1941

A price list of publications of the Geological Survey, complete to May, 1931, and with separate monthly notices of publications to (late, will be sent upon application to The Director, United States Geological Survey, Washington, D. C. A leaflet is issued each month listing new publications; it will be sent upon application to the Director, as well as Circulars containing information about topographic maps. Book publications of the Survey include (1) Annual Reports, (2) Monographs, (3) Professional Papers, (4) Bulletins, (5) Water Supply Papers, (6) chapters and volumes of Mineral Resources of the United States, (7) Folios of the Geologic Atlas of the United States and the World Atlas of Commercial Geology, (8) Topographic Folios and Topographic Maps that bear descriptive texts. Monographs, Folios of the Geologic Atlas of the United States and the World Atlas of Commercial Geology, and Topographic Folios and Topographic Maps, are not distributed free. A publication of one of the other classes can be distributed free only until the end of the fiscal year following that in which it was issued. No person can obtain more than one free copy of the same publication, and general requests for free publications, such as all of any series or all on any subject, can not be granted. In ordering publications one is requested to give both the series designation, as Bulletin 738 or Professional Paper 122, and the title. Give full address, plainly written, including county. Prepayment is required and may he made by postal, or express money order payable to the official charged with the sale of the publications. requested, as indicated in the discussion of each classification following; or it may be made in cash-exact amount -at sender&apos;s risk. Postage stamps are not accepted in payment for publications.

Jan 1, 1933

By Anson Hayes, John Chipman

The quality of sheet and strip products made of rimming steel is closely related to the structure and chemistry of the ingots. The variation in composition throughout the ingot, as affected by segregation, is of great importance, as are also the form and distribution of the voids that result from the gases evolved. It is because of this importance that the considerable literature in this field has accumulated. No attempt is made in the present paper to compile a bibliography of the excellent work that has already been done, as this has been adequately covered in the many excellent reports on the heterogeneity of steel ingots prepared by a joint committee and published by the Iron and Steel Institute.&apos; From time to time, in any field of investigation new tools and new technique are developed, which make further progress possible. In the field with which this paper is concerned, this is true. The development of the vacuum-fusion method as a means of following oxygen segregation, and a technique for obtaining the volume and composition of the gases evolved during solidification, have opened the way to obtaining data by means of which some considerable progress has been realized in developing more of the detailed mechanisms of solidification and segregation in rimming-steel ingots. General Theory of Segregation The basic cause of segregation lies in the fact that the impurities are less soluble in solid than in liquid iron. The solid that forms from the impure liquid is more nearly pure than the liquid itself. If solidification proceeds slowly enough, or if the liquid and solid phases are maintained in contact with one another for a sufficient time, a condition of equilibrium is set up, which may be represented by a phase diagram. Portions of the

Jan 1, 1939

By Anson Hayes, John Chipman

The quality of sheet and strip products made of rimming steel is closely related to the structure and chemistry of the ingots. The variation in composition throughout the ingot, as affected by segregation, is of great importance, as are also the form and distribution of the voids that result from the gases evolved. It is because of this importance that the considerable literature in this field has accumulated. No attempt is made in the present paper to compile a bibliography of the excellent work that has already been done, as this has been adequately covered in the many excellent reports on the heterogeneity of steel ingots prepared by a joint committee and published by the Iron and Steel Institute.&apos; From time to time, in any field of investigation new tools and new technique are developed, which make further progress possible. In the field with which this paper is concerned, this is true. The development of the vacuum-fusion method as a means of following oxygen segregation, and a technique for obtaining the volume and composition of the gases evolved during solidification, have opened the way to obtaining data by means of which some considerable progress has been realized in developing more of the detailed mechanisms of solidification and segregation in rimming-steel ingots. General Theory of Segregation The basic cause of segregation lies in the fact that the impurities are less soluble in solid than in liquid iron. The solid that forms from the impure liquid is more nearly pure than the liquid itself. If solidification proceeds slowly enough, or if the liquid and solid phases are maintained in contact with one another for a sufficient time, a condition of equilibrium is set up, which may be represented by a phase diagram. Portions of the

Jan 1, 1939

By C. Schlumberger, M. Schlumberger

In order to explore electrically a terrain composed of a succession of horizontal beds, a current of known intensity i is caused to flow between two grounds A and B, and the resultant drop of potential , caused by the resistance of the earth, is measured between two given points in the soil, M and N. In practice it is convenient to choose the two points M and N so that they lie on the line AB and their midpoint coincides with the middle 0, of that line, although this is not imperative. When the lengths L and I of the two lines AB and MN are varied, equations are obtained which may be solved for the resistivity p of the subsoil at various depths. Recall briefly that the formula 4 x l gives the average resistivity, in the horizontal direction, of a layer of earth which extends to a depth1 about equal to L/4. This elementary concept is adequate for numerous practical applications. Nevertheless, it must be said that, in many cases, a rigorous mathematical analysis may be made, provided it is always a question of homogeneous, superposed horizontal beds. The authors expect to publish, later on, appropriate methods of calculation for some specific cases.

Jan 1, 1932

By Nelson Severinghaus

Mineral fillers have been defined as inert materials that are included in a composition for some useful purpose. Because this definition and the scope of this review are not specific-indeed, exceptions abound-accurate total statistics are unavailable. One source estimates the total production in the United States in 1979 at 11.3 Mt (12.5 million st) valued at $534 million, averaging $49.19 per ton. Included are a broad group of minerals-asbestos, barite, bentonite, ground limestone and dolomite, clays, diatomite, feldspar, micas, silica, talc. Additional references will be made to synthetic mineral-derived fillers such as aluminum hydrate, precipitated calcium carbonate, and pyrogenic and precipitated silicas and silicates. A section on related uses at the end of this chapter covers absorbents and filters. Mineral fillers can be included in compounds to accomplish a variety of final results. Hardness, brittleness, impact strength, compressive strength, softening point, fire resistance, surface texture, electrical conductivity, and a host of other physical characteristics may be modified by the inclusion of fillers. These effects are the result of properties of the fillers, including chemical activity, hardness, particle size, shape and distribution, surface structure, color, density, and refractive index. To facilitate an overview of the mineral filler industry, this chapter will review the general usage of fillers, the inherent characteristics that intensify their utilization, and similarly their manufactured characteristics. Major using industries will then be examined in detail. Specific information on deposits and processing for industrial minerals will be found in the appropriate commodity chapter. All of these same minerals have additional significant uses based on their chemical composition or other characteristics. References will be found in other use chapters and summarized in commodity chapters. The chart in Table 1, updated from the 4th edition of Industrial Minerals and Rocks, illustrates the major mineral fillers (both natural and manufactured) and their more important end uses. Use of Mineral Fillers Archaeologists have found that more than 5000 years ago, bitumen used for mortar and waterproofing contained mineral contaminants that acted as fillers. Since that time man has added mineral products to compounds to improve certain characteristics. Perhaps the most common objective of filler usage is reduction of cost of the end product. Certainly the inclusion of a filler that costs 2¢ per 0.45 kg (lb) will reduce the cost of a plastic product whose resin costs 50¢ per 0.45 kg (lb). But the decision to use a specific filler is not that simple. It may "soak up" binder, making a compound more viscous and perhaps preventing its flow into a mold as an injection molding compound, but similarly will give good anti-sag characteristics to putty, caulking compound, or undercoating. Fillers may be incorporated to modify: 1) Cost 2) Physical characteristics 3) Flow characteristics 4) Fire resistance 5) Density 6) Heat conductivity 7) Color or brightness and opacity 8) Hardness, brittleness, impact strength 9) Deformity, viscosity, softening point 10) Processing problems 11) Electrical conductivity 12) Surface texture 13) Thermal expansion characteristics 14) Abrasion resistance

Jan 1, 1983