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By Philip D. Wilson

FEAST and famine-or, chronologically, famine and feast-have characterized the aluminum supply program during 1943. Fortunately for the war effort the famine phase is over and aluminum production is now in the happy position of being abundantly able to supply all the requirements of the armed services plus a monthly surplus which is building up a substantial stock pile as a reserve against any contingencies. But the present condition of oversupply cannot be attributed to the super-efficiency of the aluminum production program which was designed to take care of the over-all requirements of the war with little or no margin of safety. The present more than comfortable situation is due primarily to the fact that the armed services generally have not consumed anything approaching the amount of aluminum which their requirement estimates indicated.

Jan 1, 1944

By M. J. Pool

The partial molar heats of solution in liquid tin of cadmium, silver, tellurium, and zinc have been measured at 655°. 700°, and 750°K by liquid-metal solution calorimetry. Silver, cadmium, and zinc are endothermic at these temperatures while tellurium is exothermic. Only the heat of solution of silver depends on composition while all four elements show a temperature-de pendent heat of solution. The heat of solution of tellurium is constant up to 0.6 g-at. pct, becomes increasingly more exothermic, and reaches a limiting value at 1 g-at. pct Te. The limiting value has been used to calculate the heat of formation of SnTe at 750°K. The heat effects associated with the dissolution of the compounds Ag2 Te, CdTe, and ZnTe in liquid tin were measured at 750°K. These values are cotnOined with the measured hat effects at 750°Kfor silver, cadmium, tellurium, and zinc to detertrline the heats of formation of the telluride compounds. Cadmium lelluride exhibits a heat of dissolution which has a compositional dependence. THERE is a considerable amount of interest in the compounds of tellurium because of their electronic properties. Both cadmium and zinc tellurides are thermoelectric materials and considerable work has been done on their electronic properties but a limited amount of data is available on their ther-modynamic properties. This work was undertaken to elucidate the heat of formation data on cadmium and zinc telluride. Since both cadmium and zinc are in Group II it seemed to be of interest to compare the values obtained for them with the heat of formation of a Group I telluride. Silver telluride was selected for this comparison. In the course of the work it was also possible to determine the heat of formation of tin telluride and therefore to make a comparison of some of the Group I, 11, and lV tellurides with the metallic elements silver, cadmium, and tin being in the same period. There is also a great deal of interest in the energetic changes which occur upon addition of solute elements to a common solvent. This investigation provided an opportunity to study the partial molar heats of solution of silver, cadmium, tellurium, and zinc in liquid tin. The partial molar heats of solution are of theoretical interest because solute-solute interactions are a minimum in dilute solutions and application of solution models is simpli- fied. In order to complete the analysis of solute-solute and solute-solvent interactions the temperature dependence of the partial molar heats of solution was also measured. MATERIALS AND EXPERIMENTAL PROCEDURE All materials were of the highest purity available. The silver, zinc, cadmium, and tellurium were obtained from American Smelting and Refining Co. and were reported to be 99.999 pct pure. The silver telluride, zinc telluride, and cadmium telluride were obtained from Atomergic Chemetals Co., a division of Gallard-Schlesinger Chemical Manufacturing Corp., and were electronic-grade material of 99.999 pct purity. Tin used for the solvent bath and for calibration was obtained from the Vulcan Manufacturing Co. and was reported as being 99.99 pct pure. The liquid-tin solution calorimeter used in this work is similar in principle to the differential twin-type calorimeter described by K1eppa.l Two of three identical calorimeter wells are used together during any set of experiments, one well being active and the other being passive. The wells are positioned 120 deg apart in an aluminum calorimeter block. Each well contains a multijunction thermopile and a Pyrex test tube to hold the liquid metal bath. Forty-eight of the thermopile junctions are distributed over the surface of each calorimeter well adjacent to the test tube and serve to integrate the heat effects occurring. The other forty-eight are next to the aluminum calorimeter block. The thermopiles for the three wells are connected differentially so that any change in temperature at the outer junctions (which will be the same for both wells because of the high conductivity of the aluminum block) will oppose for the two wells and result in no shift of the zero. The electrical output represents the true temperature difference between the two reaction vessels. A reaction occurring in the active well gives a comparison with another body of very similar thermal properties. In this way, any spurious heat effects due to slight temperature drifts within the entire calorimeter block are eliminated. The output of the differential thermopile goes to a dc amplifier with multiple ranges of from * 10 pv to 1 30 mv. The output of the amplifier is then fed into a Leeds and Northrup strip-chart recorder. The adiabatic temperature change is then calculated using the technique of Howlett, Leach, Ticknor, and ever.' The aluminum calorimeter block is contained in a cylindrical furnace with main and control heaters

Jan 1, 1965

By G. A. Koenig, Moritz Stockder

Locality and Geological Occurrence.—The Atpine region of Southwest. Colorado. cort~prieiog the San Juan and Uncon~paghre Mountains, is con~posed of a deeply eroded sheet of acid eruptive rocks, overlying in part gneissic schiets, and in part limestones and sandstones, including portions of the Silurian, Devonian, arid Carboniferous systems. The section is clearly and beautifully exposed along the Uncompghre River from its headwaters to its exit from the mountains. The river's course from the town of Ouray towards the Los Pinos agency is due north, and four miles from Ouray, in this directiou, the Uocampaglire receives from the east the Red Casm Creek. Following up the narrow canon we find the section through white. sandotone in strata dipping to the north and west, and belonging either to the lower or middle Devonian system. Presently the steep cafion-like character of the ravine gives place to more gentle slopes, ad we have entered crysralline rock—porphyry. The contact is well marked, for the sandsbne, to a depth of from six to ten feet, resembles quartzite, i. e., is serui'fusd. Ascending still higher, a small

Jan 1, 1881

By Thomas R. Smith

This paper covers oil shale resources in those countries that border the Pacific Rim. The major known resources around the Pacific Rim occur in the Western United States, Australia, the People's Republic of China, (PRC) and the Thailand/Burma region. The location of these deposits is shown in Figure 1. In 1965, the U.S. Geological Survey estimated world oil shale deposits of over 4 quadrillion tons having a potential oil yield of over 2 quadrillion barrels. If all this were extracted, it could meet the world's entire energy needs far into the future. However, the Survey also estimated the spent shale waste could cover all of the surface of the world to a depth of about 10 feet. Thus, for this and many other technical and economic reasons, it does not appear to be feasible to develop a large portion of the world's oil shale resources in this century; nor will shale in itself solve our energy problems. Nevertheless, shale oil and other ' synthetic fuels are expected to play an important role in new energy supplies in the longer term. WHAT IS OIL SHALE OR SHALE OIL? The term "oil shale" is sometimes a misnomer, in that the rock is often more of a limestone or siltstone than a shale. The common link between resources termed “oil shale" is that they all contain an insoluble substance cal led kerogen (which is from the Greek words for waxmaking). Kerogen is a form of organic carbon derived from a variety of plants ranging from algae to higher plants. When heated sufficiently, the kerogen generates hydrocarbons called shale oil, a form of synthetic crude oil that in most cases is lower in hydrogen content than conventional crude oil. The amount of oil in oil shale is relatively small --roughly 10 percent (by weight) in the richer shales. To upgrade this synthetic oil to usable products, additional processing is necessary. This brief sketch gives an idea of what this different, but significant, form of hydrocarbon is like. ENVIRONMENTS OF DEPOSITION Most oil shale deposits fall into three environments of sediment deposition: 1ake (called lacustrine), sea (marine) and river (fluvial-deltaic). In each case, the deposition of oil shales took place in quiet water environments where plant life, particularly algal plants, could flourish and, after dying, be deposited in unoxygenated water where the kerogen precursors would be safe from destruction by oxidation. The oil shales that were deposited in large lake basins (lacustrine) have attracted the most attention for development over the years. They often have multiple seams, deposited in a cyclic nature with extensive areal distribution and rapid vertical changes in kerogen content. Grades are moderate to high, ranging from 80 to 200 liters per tonne. Rundle in Australia and the Piceance Creek Basin in Colorado are examples of this type. Both deposits represent large volumes of oil shale in small areas which could provide the large volume of feedstock needed for future commercial operations. The stratigraphic sections of these two deposits feature thick oil shale seams with average grades of 80 - 125 liters/tonne conducive to both open pit, and underground operations. However, the rock strength of the Rundle shale is not sufficient to - support underground mining. On the other hand, the Colorado deposits, being more carbonate in nature, are sufficiently strong to support either type of mining depending on the overburden to ore ratio. These latter types of deposits will likely provide the first target for development of a commercial industry. The marine type is characterized by extensive areal distribution with relatively thin seams. The grades are generally low to moderate, ranging from 50 to 120 liters per tonne. The marine oil shales are common worldwide, and their attractiveness for mining is dependent on the overburden to ore ratio. Because of their widespread areal distribution, their in situ resources can be quite large. The Toolebuc Formation in Central , Queensland, Australia is a good example of this type of deposit being 7-10 meters thick over an extensive area. The Julia Creek deposit with its favorable overburden-to-ore ratio is being studied for possible development. In a fluvial-deltaic environment, there are many small lakes or bogs associated with rivers in which a very pure type of oil shale called torbanite could form. Torbanites are very high grade containing up to 75 percent hydrocarbons. The known occurrences are generally small lenticular deposits associated with coal seams. Even with the high grades, it is not likely that any of the known deposits would warrant commercial development because of their small size. The torbanite deposits in New South Wales, Australia were processed prior to World War I1 near the town of Glen Davis. However, today's known resources of this type are not large enough to warrant a commercial plant.

Jan 1, 1982

By ROBERT E. CROCKETT

MAGNETITE mining and milling in New York, New Jersey and Pennsylvania continued to remain comparatively inactive during 1933, owing to the low rate of output of the steel industry and also to unrestricted importation of foreign ores. However, some improvement over conditions existing in 1932 was noticeable, particularly in New Jersey, where one plant, that of the Washington mine of the Alan Wood Mining Co., at Oxford, went on full production in August. At Lyon Mountain, N. Y., the Chateaugay Ore and Iron Co. resumed mining and milling operations in October, on a reduced scale, principally to provide employment during the winter months. The Chateaugay company produces a special low-phosphorus pig iron. During the year they obtained a contract to supply their product for use in the manufacture of the suspension cables of the New. Golden Gate Bridge.

Jan 1, 1934

By W. N. Poundstone, G. R. Spindler

A comprehensive report on extensive experimentation in degasification of the Pittsburgh Coal seam is presented. Detailed accounts of the procedures and results are given for permeability tests, vertical bore hole tests, measurement of gas flow from sealed drainage areas, horizontal rib hole tests, and water infusion tests. The removal of methane gas from coal seams in advance of mining is not a new idea with mining men—much attention has been given to the possibility for many years. In other parts of the world, a principal concern has been in the recovery and utilization of the gas and a number of successful projects have been developed in Europe and elsewhere. In this country, the principal motivation has been related to the safety aspect with some possible side benefits concerning costs and efficiency in mining as secondary objectives. To date, experimental work in this country has been largely or entirely exploratory to determine bed characteristics with respect to the liberation of combustible gases to investigate or establish the possibility of degasification in advance of mining and as an aid in projecting mine ventilation systems to provide for safe, effective and economical handling of combustible gases liberated during mining. With these objectives in mind, the School of Mines and Engineering Experiment Station at West Virginia University, in cooperation with the Christopher Coal Co. of Osage, W. Va., initiated some experimental work in May 1952 and the project has been more or less continuous since that time. The work has been centered entirely in mines of the cooperating company in Monongalia County, W. Va., and Greene County, Pa. LOCATION AND GENERAL CONDITIONS OF THE AREA The principal mining in the area involved is in the Pittsburgh coal seam which lies at the bottom of the Monongahela series of the Pennsylvanian. The Pittsburgh coal in the area is generally uniform in its structure and physical characteristics. The bed thickness averages about 7 to 8 ft and the coal has a characteristic blocky structure as the result of pronounced face cleats and definite, but somewhat less pronounced, butt cleavage. It is a medium volatile coal, averaging about 37 pct, and is marketed principally as a steam fuel and for metallurgical purposes. The Pittsburgh coal outcrops along the Monongahela River and dips gradually, but not uniformly, slightly north of west (about N75°W). The westward extensions of the bed, from the areas contiguous to the Monongahela River which have been heavily mined, constitute the principal reserves and are all well below drainage with the depth of cover increasing with the distance from the river. In general, with deeper cover, it may be expected that methane liberation will be more of a problem in future mining as compared to areas mined previously; therein lies the interest in possible de-gasification in advance of mining. Fig. 1 shows the Pittsburgh coal area in the vicinity of Morgantown in Monongalia County, W. Va., and Greene County, Pa., in which the experimental work discussed is located. Fig. 2 shows the contours on the Pittsburgh coal in the test area. It will be noted that the first two bore holes for the experiments were at the edge of a bench or terrace with considerable change in the gradient in the immediate vicinity of the test holes and that the same general condition applies to later test areas. Mining is intensively mechanized in the area and in the mines involved in the experimental work with corresponding rapid advance of working faces a typical characteristic. In the areas now mined the total methane liberation ranges from moderate to relatively heavy, but the actual face liberation is extremely variable and may range from practically

Jan 1, 1961

Charles Catlett, Staunton, Virginia (communication to the Secretary*): I have had occasion to examine a few of the irondeposits in the immediate section of which Mr. Watson speaks, but have not had an opportunity to visit any of the well-known manganese-deposits. I find the former can be very safely read in light of the information which it is possible to get from the same measnres farther. north, where they are less completely decomposed. In the same way all of his conclusions in regard to the geology of the manganese-deposits bear out their occurrence in Virginia, when we allow for the far more complete decomposition in the section he has so carefully studied. Judging from the same measures farther north, I think he will be safe in agreeing even further with Penrose as to the origin of these ores. Some years ago I carried on prospecting work in these measures in Virginia, in which the iron-ore and manganese-ore were followed down to undecomposed material, and in which their occurrence along a definite line of stratification, and apparently a part of the original bedding, was plainly shown. This is unusual, however, even in the section of which I speak. At Crimora, Virginia, the decomposition is quite complete; at the same time the results of some hydraulic work, which has been done there, disclosed, at the time of my last visit, the manganese interbedded in the residual clay along a definite and distinct plane parallel to the bedding of the underlying quartzite, and which, as is shown at other points, corresponds with the plane of the original material. In view of the phosphorus reported by Mr. Watson as existing in the Cartersville ores, and the not uncommonly prohibitive amount in southern ores, I am interested to know whether

Jan 1, 1904

By A. J. Opinsky, J. L. Orehotsky, L. L. Seigle

TUNGSTEN incandescent lamp filaments possess a typical structure of elongated crystals generated upon heating the silica-alumina doped wire rapidly to 2200°C or above.&apos; It is known that these very long grains exhibit a preferred orientation, but there is disagreement in the literature about the direction. Rosi,2 and later Rieck; reported that the <135> direction of the large grains in doped wire tends to be parallel to the wire axis, but other investigators have reported that <110> is the preferred direction. Some further investigation of the orientations of large grains in tungsten wire is reported in the following. In the first series of experiments, 6-in. lengths of wire were heated rapidly in a bell jar. Current was passed through the wires and within 15 sec the wires had reached the grain coarsening temperature. 2 min was the annealing time. Wires were heated in hydrogen, nitrogen, and vacuum. Later, wires were heated in an evacuated tube furnace in which the tube was brought from 1000°C to the operating temperature within 25 sec and held 5 min at temperature. Temperatures were measured with an optical pyrometer. After heating, the wires were electro polished and etched, and the orientations of the large grains determined by the Laue back-reflection technique. Most of the experiments were carried out on a single spool of 5-mil silica-alumina doped wire, but a few tests were made with 5-mil thoriated tungsten wire and 10-mil undoped wire. 5-mil silica-alumina doped wires were reduced to smaller diameters by electropolishing for one series of experiments. Orientations of the large grains in silica-alumina doped wire heated in various atmospheres are presented in Figs. 1 and 2 as plots of the direction of the wire axis relative to the cube axes of the crystals. For most of the conditions studied, the preferred orientation cannot be described as a single direction, but the points might be said to group themselves about the arc passing through <110> and <113>. This arc is the trace of the (211) planes and contains the <135> and <124 as well as <011> directions previously observed by other investigators. The preferred orientation of large crystals in silica-alumina doped tungsten wire might be most generally described, therefore, by stating that a (211 ) tends to be parallel to the wire axis. This is true also for wires reduced in diameter by etching and furnace heated, Fig. 2, i.e., the recrystallization texture is apparently unchanged upon removal of the outer layers and substantially independent of the temperature gradient within the wire.

Jan 1, 1962

By Eugene McAuliffe

THE Coal Division undertook its most ambitious program this year at the New York meeting, with six full&apos; sessions and a luncheon on Monday which had a record attendance and at which the newly elected officers for the Division were announced. Eugene McAuliffe, president of the Union Pacific Coal Co., Omaha, Neb., was unanimously selected as Chairman; J. B. Morrow, preparation manager of the Pittsburgh Coal Co., as Vice-Chairman; and H. E. Nold, Ohio State University, Secretary. During the past year two new and interesting activities were conducted by the Division directed at stimulating the interest of junior and student members. Reports were presented at the luncheon meeting by the chairmen of these commit¬tees. J. B. Morrow. chairman of the paper prize awards, and H. N. Eavenson reported on the work of the mining machinery manufacturers fellowship, the work on which was completed the first of the year. Several excellent papers are expected from these two groups for the next meeting of the Division to be held in Pittsburgh some time in the fall. The regular six-session program was filled from start to finish with interesting papers and much discussion, but unfortunately not enough time for the latter. The papers covered the field of prospecting, mining methods, preparation, utilization, mechanization, and safety, and all through the program we were constantly reminded of the value and need of research in the coal industry.

Jan 1, 1936

By Ira B. Jorafemon

In the interesting Institute symposium of the preservation of peace by force, through mineral control, one important aspect of the question was not presented. This is the responsibility the United Nations, and particularly the United States, will incur the through limitation of the economic activities of nations that are now friendly to us, as well as of nations that are enemies or are under the control of enemies. After the war all nations, friends as well as enemies will be poor. Hunger and bankruptcy will, will like the sword of Damocles, hang over the heads of all of us on this blundering planet. When the actual fighting is over, there will be a universal attempt to squirm out from under the sword by resuming production of peacetime goods, for trade as well as immediate consumption.

Jan 1, 1944

By Emery C. Olsen

Most coal mining areas of the Western United States are characterized either by thick beds, steep pitches or heavy cover. Individually, each of these may present inherent safety hazards that influence mining. When all are met at one location, the combined effect is to make the safe operation of the mining property a challenge to management. These combined conditions are met in the coal mines of the Columbia-Geneva Steel Div. of the United States Steel Corp., in southeastern Utah. This coal bed measures up to 16 ft in thickness, the pitch is as much as 25 % and mining is under a cover approaching 3000 ft. The Sunnyside coal bed is found in the Book Cliff Mountains, a great escarpment extending from west of Castle Gate, Utah, some 180 miles to Grand Junction, Colo. West of Green River, Utah, the Book Cliffs swing sharply to the north because of the domelike uplift of the San Rafael Swell to the south- west. It is in this northerly extension of the Book Cliffs that the Sunnyside coal in the Blackhawk Formation of the Mesa Verde Group, Upper Cretaceous Age is found. The strata are transected by numerous faults with from a few inches to as much as a hundred feet of displacement. All of these faults have had some effect on the mining operation, either in roof control or, in the case of major faulting, the pattern of mine development.

Jan 10, 1963

By J. Mazia, H. Rosenthal

An investigation has been made of residual stress in the head and body of caliber 0.30 cartridge cases. The head was divided into four ring-lie sections which were cut off by a jeweler&apos;s saw. Spring-out was measured after a radial cut had relieved the circumferential bending moment. The residual stress corresponding to the observed spring-out was calculated by formulas in which the computed stress was a function of wall thickness. All rings sprang open, indicating compressive stress on the inner wall and tensile stress on the outer wall. The production stress-relief anneal of 475 F. for 45 min. reduced the stress to almost half. The priming and crimping operation, however, again raised the stress, especially in the flange section. The dect of stress-relief heat treatments on residual stresses in the body of caliber 0.30 cartridge cases was investigated by the split-ring method. Although this method did not reveal any large stresses in the body, the neck before mouth anneal was found to contain a computed stress of 30,000 psi. at the surface. This value was reduced to 15,000 psi. in 120, 30, and 15 min. at 400, 475, and 500 F., respectively.

Jan 1, 1945

By B. A. Rogers

THE etching effect which is produced on a piece of polished iron or steel when it is heated in hydrogen or in a vacuum seems to have been observed first by Osmond,1 who believed that he could distinguish four systems of grain boundaries on a piece of steel which had been heated in hydrogen. In a number of other investigations, samples of pure iron were found, after heating, to have complex networks in which two or three systems of grain boundaries could be detected. It was further noticed that samples that had been polished plane before being placed in the furnace were, after treatment, roughened and undulating over their entire surfaces. From a comparison of the temperature of heat treatment with that of the A 3 transformation, it was concluded that the changed appearance of the samples was definitely related to the latter phenomenon. Certain other deductions were made but these are not of importance here and only observations on the appearance of the samples will be reviewed. Ewen2 heated a strip of polished iron in a vacuum in such a way that one end was maintained at a temperature of 1000° C. and the other at 580° C. On the cooler end there was outlined a simple polyhedral network, and at the hotter there appeared the complex system of lines and the undulating surface characteristic of iron which has passed through the A3 transformation. He found that in going from the cooler toward the hotter end the sample maintained much the same character of surface up to the beginning of the transformed area, but that near this region double grain boundaries were of frequent occurrence. Rawdon and Scott&apos; concluded that the simple type of network brought out by heating a sample of pure iron in a vacuum was of the same type as that developed by ordinary etching methods. They also confirmed the observations of

Jan 1, 1929

By M. J. Blackburn

The ordering reaction and its effect on dislocation awangements in alloys based on Mg3Cd has been studied by transmission electron microscopy. Ordering occurs by the growth of ordered domains until they impinge, thus producing an antiphase domain boundary (APB) network. In the disordered alloy, slip is confined to the basal plane while in the ordered condition slip occurs on the basal, prism, and pyramidal planes. Superdislocations have been identuied on these planes and their origin and expected spacings are discussed and compared with the observations. The APBs between the dislocation pairs have been resolved and have proved useful in the identification of superdislocations. Observed slip structures are related to the changes in mechanical properties produced by ordering. At high temperatures magnesium and cadmium form a continuous series of disordered hexagonal solid solutions. At lower temperatures three ordering reactions occur; two based on the compositions Mg3Cd and MgCd3 are transformations to DO19-type superlattices while alloys based on the composition MgCd transform to a B19 lattice. The ordering process in alloys near the composition Mg3Cd has been studied by several workers&apos;-4 and it has been shown to be a first-order type transformation. The variation of mechanical properties with the degree of order and temperature have been reported in some detail by Stoloff and Davies.5 It was shown that the disordered alloy was stronger and less ductile than the ordered alloy, the differences being attributed to changes in the number of active slip planes and to the presence of short-range order in the disordered alloy. In this investigation the ordering reaction has been qualitatively followed by transmission electron microscopy. The effect of this ordering transformation on the dislocation arrangements in deformed specimens has been studied in some detail. EXPERIMENTAL Alloys were melted in a stainless-steel crucible under a flux and chill cast; both melting and casting were performed in an argon atmosphere. The ingots were hot-rolled and tensile specimens cut from the resultant strips. Some large-grained specimens were grown by the strain-anneal method. Heat treatment was carried out in inert atmosphere furnaces and in oil baths at the lower temperatures. Thin foils for transmission electron microscopy were produced by electropolishing in a cooled solution (temp = -40°C) containing 50 cu cm of nitric acid and 180 cu cm of methanol at a potential of 10 v. The ordering reaction was followed by transmission electron microscopy, X-ray, and electrical resistivity measurements but this paper will be concerned chiefly with the electron-microscopy results. Much of the work described in this paper was performed on an alloy containing 26.10 at. pct Cd although two of the micrographs are taken from work on a 25.55 at. pct Cd alloy. RESULTS i) The Quenched Solid Solution. Specimens which were quenched from above the critical temperature showed diffuse superlattice reflections. sark-field analysis on these reflections failed to reveal the presence of ordered domains and thus the superlattice reflections were assumed to arise from regions of short-range order. Quenching from temperatures of 400" to 450°C results in the formation of dislocation loops and helical dislocations. Such defects have been observed and analyzed in detail in several hexagonal metals6-&apos; and as the crystallography and interactions of such loops appear similar in this alloy they will not be reported in detail. Fig. 1 shows a high density of loops

Jan 1, 1968

By C. E. Birchenall, M. H. Davis

The rate of oxidation of titanium in the temperature range 650° to 950°C has been measured. &apos;The linear rate law obtained is explained by interface reaction control of the process. Tracer experiments indicate the oxygen diffuses in at least one phase of the scale. THE kinetics of oxidation of titanium, principally at low temperatures and under varying oxygen pressures, have been reported.¹,² In the present investigation the rates of oxidation of titanium have been determined by the gravimetric method in the temperature range 650" to 1000°C under 1 atm of oxygen. Some of the scales formed were powdered and an endeavor was made to identify the phases present by X-ray diffraction. Alexander and Pigeon1 ascribe a logarithmic rate law to the growth of thick films formed at temperatures up to 565"C, and Gulbransen and Andrew&apos; suggest that the parabolic rate law holds up to 600°C. In both cases large initial deviations from those relationships are apparent and no explanation is offered. In the present experiments it is shown that a linear rate law holds in the temperature range 650" to 1000°C, and it is suggested that the initial deviations observed are due in part to a spurious surface area effect and also to the high solubility of oxygen in titanium metal. Positive information on the mechanism of oxidation is not available, but oxygen ion diffusion through the lattice is inferred from the re- sults of trace experiments. X-ray analysis of the scale confirms Gulbransen and Hickman&apos;s&apos; observation on the presence of rutile TiO². Experimental Details The titanium used in these experiments was prepared by the reduction of titanium tetrachloride with magnesium and was used in the form of rolled sheet. Samples approximately 0.040x0.5x0.75 in. were cut and polished to a fineness of 4/0 on metal-lographic polishing papers. Individual samples, suspended on a platinum wire, were lowered into the hot zone of a furnace, in vacuo, by means of a winch, and oxygen was admitted after the desired temperature was attained. The increase of weight of single samples oxidized for fixed times at certain temperatures was determined by weighing the sample before and after oxidation on a chemical balance. In these instances the sample was used for only one time at one temperature. In some cases the course of oxidation was followed by attaching the sample to a sensitive spring balance and noting periodically the extension of the spring with time of oxidation. Kirkendall type experiments were carried out by marking the surface of the titanium prior to oxidation with a solution containing radioactive silver. After drying, the specimen was heated in vacuo to decompose the silver nitrate used, leaving a small amount of metallic radioactive silver on the surface. Following oxidation, these samples were mounted, ground, and then placed in intimate contact with

Jan 1, 1952

By C. F. Willis

Many of the failures in vocational education are due to the fact that the educational methods were not designed to the capabilities, habits, and environments of those to be trained; rather they were based on the policy that education is education and lessons are lessons, whether for youngsters of fifteen or for men of forty. Vocational education among miners involves, first, a study of the men themselves, their habits, and the use of their leisure time; second, a study of the differences between the methods of teaching required for men and for children. Certain fundamental requirements of training methods for miners are reasonably universal and may be applied with success to any ordinary mining community. The rate of labor turnover is another consideration; it would be useless to design a four-year course for men who remain in one place only a few months. Length of Course The first consideration should be the length of the course. Few mining communities have a sufficiently stable population to make it possible successfully to carry on a course for over a year. While some men might complete a four-year course, the number is comparatively small compared with the number to whom a shorter course would be of service, and it is better to raise the standards of education even a little for a large number than to raise them to a high level for a few. It is perfectly possible to attain both objectives by arranging the courses in small units; all the units, when grouped together, should comprise a fairly complete course, yet any one unit should be complete in itself and of benefit to the workman. It should not take many of these units to make a miner or a timberman out of a mucker; but to do this the course should be short, because muckers seldom stay in one place long. By grouping a number of these units together it Would be possible for a miner to become a shift boss or a shift boss a foreman, and so on. As far as possible the units of the course should not be dependent on those preceding or following. The workman understands the completed job but he is not accustomed to carrying on several jobs at the same time and

Jan 1, 1920

By AIME AIME

ELECTRICAL methods of geophysical exploration attracted major attention at the three sessions devoted to geophysics on Monday and Tuesday. At the opening&apos; meeting Monday morning Hans Lundberg gave the paper by himself and Folke Kihlstedt; he described the use of the Racom, discussed last year, and the method whereby it is possible to eliminate all but subsurface, effects in electrical exploration. In the discussion Theodor Zuschlag pointed out some of the theoretical considerations behind the field procedure. Karl Sundberg&apos;s paper on the effect of impregnating waters was presented by title only, and S. F. Kelly then gave an abstract of a paper on the electrical properties of ores, by J. J. Jakosky, R. N. Anderson and Clyde H. Wilson. , This dealt with an exhaustive series of laboratory tests on the variation of -conductivity of ore specimens with the frequency of the energizing current, and of the effect of moisture content in typical clays and gouges on their conductivities at various frequencies. Considerable discussion was provoked during which the authors came in for some-criticism on their measuring circuits and for their assumption that a solid conductor could be compared with linear ones. They were praised, however, for making a start toward a compilation of resistivities for ores and rocks. Dr. Slichter disagreed with them that the conductivity of an orebody was primarily capacitive. He also called attention to the fact that it was high time geophysicists adopted the standard physical expression of ohm-,centimeters or ohm-meters to express resistivities. This same point was the burden of the next paper,. "Uniform Expression for Resistivity," by Sherwin F. Kelly, presented by title only.

Jan 1, 1932

By W. R. Crane

THE effect of mining in the red-ore mines of the Birmingham district has been observed for some time, but, except in a few localities, little difficulty has been experienced from disturbance of cover. Cave-ins near the outcrop and fracturing of the surface at greater distances are the most pronounced manifestations of disturbance, while limited areas at points distant from the outcrop and under greater depth of cover have actually subsided. There is no doubt but that in time, because of failure of pillars, extensive fracturing and widespread settlement of the surface will result, particularly along the slope of Red Mountain, where mining has been under way for many years. Were it not that the orebed is overlain by one or more water-bearing formations, the fracturing or settlement of the surface would not be serious; but because of these formations, fracturing of the top rock may in itself be of sufficient importance to warrant the adoption of protective measures. Until development openings and surface plants are transferred to Shades Valley, protection of the surface will probably not be considered imperative, as the area involved is not of particular value for agricultural or building purposes. Further, the collapse of pillars over a wide area may develop squeezes that, if not controlled, may jeopardize the integrity of the mines and necessitate a change in development, from slopes to vertical shafts, at a much earlier period than is now contemplated. The occurrence of heavy beds of strong tough materials at varying distances above the orebed make it doubtful whether any serious disturbance of the surface will be experienced at any considerable distance from the outcrop, although some settlement will probably take place. It is certain, however, that no great volume of water will enter the mines from fracturing of the Fort Payne chert bed, as this is known to be a compact and practically impervious formation beyond the leached zone. Not so much can be said, however, regarding other possible sources of water, as pervious beds and through faults that may be encountered in future mining operations.

Jan 8, 1925

By S. S. Raymond, C. R. Hayward

In reheating quenched steel to remove part of the hardness, the softening effect has generally been considered to be a function of temperature and time. The temperature effect is well known, and long before pyrometers were heard of the blacksmith was able to do a good job of tempering, by rule-of-thumb methods and experience in judging temperatures. Modern conditions, which demand steel that will withstand the severest tests, require that the heat treatment be carried out with every possible precaution to secure the best results obtainable. Pyrometers and heat-treatment furnaces of many types are on the market and improvements are continually being made so that it is now possible to regulate the temperature in heat treatment very accurately. There is still a question regarding the time that the steel should be subjected to treatment. It is customary with all operators to insure the desired temperature throughout the specimen and it is generally supposed that a longer treatment of a hardened steel produces a further softening but there are few published figures showing the exact effect of time of treatment at constant temperature. A search of the literature disclosed several brief statements that the tempering effect was a function of both time and temperature, but in no case were any figures given. The opinion is very generally held that the well-know tempering colors are accurate indicators of the degree of tempering. This is disputed by Brearley (The Heat Treatment of Tool Steel, page 102) who states: It has been said that the result would be the same in respect to both hardness and other properties whether the colors were obtained by a shorter heating at a higher temperature or a longer heating at a lower one. This, to say the least, is a very doubtful conclusion, and is certainly not borne out by mechanical tests on oil-hardened and tempered motor car steels which, after tempering for periods varying from 15 min. to 2 hr., show no very great bifferences. The present investigation had for its object the obtaining of some definite data regarding the effect of time, which might serve as a guide to those engaged in the heat treatment of steel. The Rhode Island Tool Co. cooperated by furnishing the steel and machining the test specimens.

Jan 1, 1917

The housing of labor and sanitation at mines in India are difficult problems to solve because-no more than two or three castes will accept the same conditions, and conditions suitable to one coal-field are not applicable to other fields. It is also necessary to consider the financial standing of the different companies. The European companies, which pay 30 per cent. and more dividends, can erect more suitable houses than the Indian companies, which are just able to keep their heads above water. The Santhal will not live in a bucca-roofed house as a permanent dwelling, and both the Santhal and Koras have an aversion to living in a line of attached huts. They have forsaken a whole, line of houses in one of which a case of sickness or death has occurred, and those houses were afterward considered unfit by all other classes of natives. The Santhals, Koras, and Douri castes will not take drinking water from a stand pipe; wells must be furnished. When well water is not available, these people will take water from the nearest pool or tank regardless of whether or not the water is stagnant. The well tops should not he completely enclosed, nor should there be a drain around the top. The ground should slope away from the well. In the Girieih coal fields, the miners have a great objection to pucca floors; they prefer earth which is lapped, easily cleaned, and renewed. As it is customary for the miner to build his own house, the company supplying the roofing material, he takes a special interest in it, keeps it in order, and hesitates to leave it. Each house is surrounded by its own bit of land, which the inmate cultivates.

Jan 12, 1918