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By J. G. Koenigsberger

The electrical specific resistance of rocks in the field is measured by sending a current through a medium of great volume, compared to the electrodes, whose resistivity should be measured. The whole resistance can be determined by the Wheatstone bridge and the specific resistance calculated by a well-known formula. The resistivity of some rocks in place in Germany and in Switzerland is given; first, of a rock near the surface, and especially near electrodes. Practical applications are made in the determination: (1) of the continuity of a conducting orebody; (2) of the surface ares of an orebody; (3) in the detection of a water-bearing fault in a salt mine. Preliminary 'observations are described: (1) on the influence of the depth of ground-water table; (2) on the detection of gas under high pressure in coal seams. The observations in this paper of the electrical resistivity of rocks and soil in place are along the lines of the very interesting method and results of the Messrs. Gish, Rooney, Hotchkiss and Fisher. 1,2 All the work described has been done since 1920. Method Used The very simple method consists in the application to the rock of two plane circular electrodes of iron or brass of a suitable diameter, with the aid of a contact substance, and in measuring the resistivity in a Wheatstone bridge with alternating current of 100 to 400 Hertz frequency per sec.). The general formula is known to be R= R0 +d/4(1/a+1/b-1.7/l+0.8(a+b)/l2) (1)

Jan 1, 1929

By C. M. Wayman, R. Bullough

The selection rules fir twinning in fcc, bcc, and hcp lattices as established in Part I are used to predict the positions, relative to the matrix (untwinned) reciprocal lattice, of reflections due to double diffraction from the twins. These doubly diffracted reciprocal lattice points, which often coincide with ordinary matrix reciprocal lattice points, are deduced from kinematical considerations. 1. INTRODUCTION. A Bragg diffracted beam under certain conditions may be rediffracted to produce a third beam i .e., the incident beam, the first diffracted beam, and the rediffracted beam). In such a case an initial incident beam is diffracted by a set of planes; the diffracted beam may then be rediffracted by a second set of crystallographically different planes. The initially diffracted beam acts as an incident beam for the second set of planes, thus resulting in a twice-diffracted beam. This twice-diffracted beam may be regarded as a singly diffracted beam from a set of lattice planes whose structure factor is zero. In order to find the reciprocal lattice point corresponding to the doubly diffracted beam, it is customary1,2 to combine vectorially the component reciprocal lattice vectors which head to the extra reflections. For example, hcp metals may exhibit the forbidden (0001) reflections.* As Fig. 1 shows, the (0001) reciprocal lattice point results from: (1010) + (1011) = (0001) Similarly, combination of the beams (1011) and (1010) gives rise to: (1011)- (1010) = (0001) As Pashley and stowell2 have pointed out, even if in fact the double diffraction points lie on the Ewald sphere, they may not actually represent observed doubly diffracted beams because the initially diffracted primary beam, i.e., the source, must also correspond to a reciprocal lattice point which lies on the sphere of reflection; however, the reciprocal lattice point corresponding to the planes causing the rediffraction need not lie on the sphere. A little consideration of the Ewald construction in Fig. 2 makes this argument clear. In Fig. 2 the incident beam is represented by the wave vector ko. This beam is initially diffracted by the lattice planes (hkl) which are represented by the reciprocal lattice vector r(hk1) The reciprocal lattice point (hkl) of course lies on the Ewald sphere in order that the Bragg condition be satisfied. The initially diffracted beam is represented by the wave vector kl. If now kl is rediffracted by a second set of planes (h'k'l') resulting in k2 the lattice point (h"k"l") must lie on the Ewald sphere if the double diffracted beam k2 is to be observed. It is clear that (h"k"l") is the vector sum of (hkl) and (h'k'l'), and that (h'k'l') need not in fact lie on the Ewald sphere. In the usual1,2 analysis the origin (000) of the reciprocal lattice is shifted to the point (hkl). However the translation (000)— (hkl) automatically shifts the point (h'k'l') to the Ewald sphere, i.e., (h'k'l')— (h"k"1"). It is to be seen that (hkl), the source reflection, must lie on the Ewald sphere; if it does not the translation (000) — (hkl) places the "new" origin off the sphere, not satisfying the Ewald construction and hence the Bragg condition. The point (h"k"1") of course must lie on the sphere if it corresponds to an observed doubly diffracted beam. It is to be noted that crystals having the hcp structure, as just discussed, are intrinsically capable (i.e., without lattice defects such as twins) of double diffraction, as contrasted to fcc and bcc crystals which are extrinsically capable (requiring lattice defects or reoriented lattice regions). The "allowed" bcc reciprocal lattice points (which comprise an fcc lattice) are (110), (2001, (211), (220), (310), (2221, (321), (4001, and so forth. The combination

Jan 1, 1967

By G. J. Wilson

Difficulties experienced in correlating vertical and lateral locations of subsurface features that are encountered in directional wells prompted critical review of the tangential method of computing directional surveys. Inherent discrepancies were indicated to cause small incremental but significantly large cumulative errors in computed vertical depth and horizontal departure. A radius of curvature method, developed for planning and analyzing directional wells, was studied as a means of more accurately calculating survey data. Errors incurred in the tangential method were not present in the radius of curvature method. Conflicting assumptions in calculating dog-leg severity by the tangential method were resolved by a new procedure that was derived from the radius of curvature method. Results of the investigation showed the radius of curvature method to be an improved method for computing directional surveys. Introduction Many improvements in directional drilling tools and techniques have been made in the past 10 years,' but the method of computing survey data has remained virtually unchanged. While use of computers greatly aids the process of calculation' and eliminates many human errors, manual and computer calculations are still made with the assumption that the wellbore consists of straight-line segments. This paper points out discrepancies in the method and presents an improved method in which the wellbore is assumed to be curved. Tangential Method The method presently used to calculate vertical depth, horizontal departure and direction coordinates with measured values of well depth, inclination angle and direction angle is termed the tangential method. This term stems from performing calculations with a series of straight-line segments, with each segment assumed to be tangent to the wellbore at a corresponding survey point. A segment is defined by inclination and direction angles measured at only the lower or deeper end. Consequently, a discrepancy or error is introduced for each segment. Errors are not of extreme magnitude, but cumulatively are significant due to the need to define as accurately as possible the vertical and lateral location of subsurface features such as pay tops, fluid contacts and fault cuts encountered in expensive directional well bores. In Fig. 1, the curved-line segment ab represents a portion of the actual borehole as viewed in the vertical plane. Points a and b are survey stations and +, is the inclination angle at point b. The curved-line segment ab is assumed to be the straight-line segment arb of a length equal to ab and tangent at point b to the curved-line segment. Lengths a'c' and c'b are equal to a'b cos +, and a'b sin +,, respectively. Point a already has been fixed by calcillations performed with survey data obtained at point a, and calculated lengths m'c' and c'b are projected as lengths from point a, rather than from point a'. Point b1 is thus fixed and assumed to represent the actual point b. Calculated length ac" is shorter than actual length ac, and calculated length c"bl is longer than actual length cb. Since b1 is the point from which the next deeper segment will be projected, errors are cumulative. Cumulative error continues to increase as long as the inclination angle continues to increase. When the inclination angle decreases (Fig. 2), calculated length ac" is longer than actual length ac, and calculated length c"bl is shorter than actual length cb. These errors also are cumulative, but differences between calculated and actual lengths are opposite in mathematical sign to differences demonstrated in

Jan 1, 1969

By D. A. Flanagan, P. B. Crawford

A study has been made of the feasibility of storing liquid meihane at low pressures in undergrohd caverns. Methane liquefies at — 258°F at atmospheric pressure. It is shown that the methane evaporation rates will rapidly decrease and cool the surrounding rock so that at the end of one month they would be between 50 Mcf/hr for a cavern of 25-ft radius and 700 Mcf/hr for a cavern of 100-ft radius. At the end of 10 years, the evaporation rates would be 18 and 100 Mcf/hr, respectively, for caverns of the same radii. The evaporation rates may be reduced by a factor of 2 to 10 by the application of insulation. The cost for mining the caverns is estimated to be $.75 to $1.25/Mcf of storage. This is substantially less than surface storage; it is believed to be safer and to result in lower maintenance, savings in space and savings in strategic materials. INTRODUCTION During the past few years, there has been an increasing interest in the economic feasibility of liquefying methane. Methane liquefaction is being considered for tanker transport; in addition, liquefaction is being reconsidered for shaving peak gas demands. Several articles have described natural gas liquefaction and the progress of the tanker in making trial runs from the United States to Great Britain to determine the feasibility of tanker transport. At the present time, pipelines are not designed to supply peak gas loads during extremely cold periods such as are oiten encountered in the North and Northeast. Gas is being stored in underground reservoirs en-route to its destination, but in many instances satisfactory storage in porous reservoirs has not been practical, especially along the Eastern seaboard where few petroleum reservoirs have been found. In England and other foreign countries, it is unlikely that satisfactory porous structures could be found, and it may be desirable to mine or excavate the rock to obtain storage. By storing the methane near the consumption point, product availability can be increased during periods of need. Methane liquefies at - 258OF at atmospheric pressure, and 1 cu ft of liquid methane will make about 600 cu ft of gaseous methane. Methane liquefaction for shaving peak gas demands was conducted in Cleveland, Ohio in the early 1940's. The Cleveland plant was designed to liquefy 4 MMcf/D of natural gas.' Development of several low-temperature processes has resulted in some improvements in the design of low-temperature storage vessels. Liquefied-methane storage vessels can be designed for various evaporation rates. The desired rate will depend on the reason for liquefaction. For shaving peak gas demands, the desired evaporation rates would be low, possibly between 0.2 and 1.5 per cent/day. For methane tanker transport and supply, the evaporation rates must be high and must equal the total daily rate of supply. It is apparent that the cost of storage facilities will depend on the objective and will vary appreciably. Surface storage of methane may cost between $3,000 and $20,000/MMscf, depending on the size and design. The failure of the surface storage vessels at Cleveland, with the resulting injury and loss of many lives, has caused considerable emphasis to be placed upon developing new, safer and improved methods of storing liquid methane. Storage of liquefied propane and butane in underground salt domes has been very satisfactory. The per-barrel cost of underground storage for any sizeable capacity is very small compared to the cost of surface storage for LPG mixtures. The larger the capacity of the underground storage, the less is the per-barrel cost. Numerous advantages appear to exist if liquefied methane could be satisfactorily stored underground, the principal advantages being increased safety, lower initial cost, lower maintenance cost, savings in space and savings in strategic materials. The purpose of this paper is to determine the feasibility of storing liquid methane underground in mined caverns. If a large spherical cavern is dug underground and is filled instantaneously with liquid methane, the surface of the sphere may approach the liquid methane temperature almost instantaneously. The temperature distribution for a sphere of radius r. in an infinite medium, initially at one temperature with spherical surface kept at T, from time t = 0, is given by Eq. 1.'

By Philip D. Shelton

INTRODUCTION Traditional design of support for permanent underground mine excavations place great emphasis on the magnitude of the maximum radial load which a specific support or lining must sustain. However, this depends upon so many factors that reliable prediction in advance of excavation is very difficult except in strong-self supporting ground. Some of the factors affecting the loads acting on a support are illustrated in Table 1. [ ]

Jan 1, 1984

By W. A. Vine

When a hole is made in a stressed solid, such as rock pierced by mine openings, equilibrium of the solid is destroyed. To restablish that equilibrium the stress condition in the rock surrounding the opening becomes rearranged. This rearrangement may or may not develop local stresses in the vicinity of the opening which exceed the elastic strength of the rock. Since stability of the opening depends, therefore, on the strength of the naturally occurring rock surrounding the opening, this rock is an engineering material of construction, and all rock affected by the associated opening or system of openings may be considered a structure. The term invert is chosen to describe the formation of the structure built from the inside, as it were, and a consequence of mining rather than an entity built for a purpose. By definition, an invert structure is formed when openings are made underground and is com- posed of that material on the solid side of a rock-air interface wherein the stress condition is affected by the associated opening or system of openings. The shape of an invert structure is never clearly defined; the skin of the structure may be mapped, and even described, but the boundary of the structure within the solid rock mass must be arbitrarily set.

Nov 1, 1955

CHARLES KIRCHHOFF, Chairman. ALBERT SAUVEUR, Vice-Chairman. A. A. STEVENSON, Vice- Chairman. HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Cambridge, Mass. John Birkinbine, J. Esrey Johnson, Jr., Felix A: Vogel, William H. Blauvelt, William Kelly, Leonard Waldo, James Gayley, Richard Moldenke, William R. Walker, Henry D. Hibbard, Joseph W. Richards, William R. Webster. Henry M. Howe, E. Gybbon Spilsbury, Frederick W. Wood. Robert W. Hunt, A. A. Stevenson is appointed an additional Vice-Chairman of the Committee. He will serve as Acting Chairman during the absence abroad of Professor Sauveur. For the meeting of the Institute which is to be held in New York City, Oct. 16 and 17, 1913, the following papers are now assured

Jan 7, 1913

By Colin J. Dixon

The full realization of the potential of computers in geological in- formation system demands new approaches to the machine representation of information. At the same time, the feasibility of such a system, particularly in commercial field, demands greater freedom in input preparation and a degree of standardization in the arrangement of subject matter system. The paper describes some of the basic notions of project "GEOSEMANTICA 70". The aim of the project is to devise means of storing real geological informations in a machine rather than the representation of the information in human language form. This is seen as the only long-term solution to the problems of the complex vocabulary of geology and the complex syntax of geological description. Effectively, a machine language is being defined, consisting of a set of symbols and a date structure for representation of geological and related information. Beyond this, is the definition of a set of rules allowing the use of constrained text as an input/output medium. The investigation is oriented primarily to the representation and handling of information about mineral deposits and the associated geographic, economic and engineering information.

Jan 1, 1969

By AIME AIME

ON the afternoon of Feb. 20 of this year a new volcano was born in the center of the State of Michoacan, Mexico, about 100 miles inland from the Pacific Coast. Creation of this new mountain - forming crater began on an almost flat cultivated field at the south margin of a small basin about a mile in diameter and having an altitude of approximately 6800 ft. above sea level. This basin is connected to a gently inclined plain that forms the Parangaricutiro valley, the chief town of this municipality, bearing the same name as the valley, being situated three miles from the site of the new crater. The village of Paracutin, from which the new volcano received its name, is about one mile to the northwest of the crater. From the City of Mexico to the volcano is a distance of 330 miles. The paved highway running from Mexico City to Guadalajara, by way of Toluca and Morelia, is left at Carapan; from here another paved branch highway goes to Uruapan. The town of Paracutin is reached by a narrow dirt road 18 miles from Uruapan and connects with a road leading to Parangaricutiro where horses may be hired for a 40-minute trip to a place where visitors can enjoy a magnificent view of the volcano. It is possible to get within half a mile of the point of eruption in this manner.

Jan 1, 1943

By C. C. Templeton, J. C. Rodgers

A key step in feed water treatment for generating wet steam for thermal oil recovery is the removal of calcium and magnesiunt hardness by cation-exchange series softening. Knowing the solubility of any scale forming salts in brines at elevated temperatures is necessary for fixing the level to which the feed water must be softened. Such calcium sulfate solubility data, previously not available above 392F, were determined by the authors in a flow equilibrium apparatus mud will be reported elsewhere. These data were used to develop a method for predicting the solubility of anhydrite in hot water or steam droplets for saturated steam pressures as high as 2,000 psig (637F). (The calcium sulfate solubility product is represented by a combination of two factors, one reflecting the effects of ionic strength and the other accounting for the effects of complex ion formation in either calcium-magnesium-rich or sulfate-rich brines.) The method is applied to a calcium-magnesium-rich brine If moderately high salinity from a pilot hot-water flood, I nd to several sulfate-rich, low-salinity feed waters and l lowdown (cooled steam droplets) samples from steam s ak operations. The predicted calcium hardness levels corresponding to the calcium sulfate solubilities agreed reasonably well with the results of laboratory solubility determinations run on the field samples. Further testing of the method is needed for brines of other composition classes. Existing field cation exchange softeners in the cases tested are performing adequately since all the samples were found to be undersaturated with respect to calcium sulfate at their operating temperatures. Introduction Prevention of scaling caused by precipitation of calcium sulfate (anhydrite) is of considerable concern in connection with thermal recovery processes using wet steam or hot water. To avoid anhydrite precipitation in a heated system, an engineer must keep the product of the calcium and sulfate concentrations in the water or steam droplets below the value of the solubility product of anhydrite for the temperature and brine composition in question. Usually it is most practical to keep the concentration product lower than the solubility product by keeping calcium low in the presence of high sulfate, or by keeping sulfate low in the presence of high calcium. This can be done by a choice of combinations of natural waters and water treatment processes (such as series cation exchange softening to remove calcium). Until recently, few anhydrite solubility data, particularly for solutions containing other salts, were available for temperatures above 392F (211 psig steam); Marshall, Slusher and Jones' studied the CaS0,-NaCI-H,O system up to 392F and surveyed the work of previous investigators. To model natural brines, one needs to study the solubility of anhydrite in aqueous solutions of sodium chloride, sodium sulfate, calcium chloride, magnesium chloride and their mixtures. Since steam pressures as high as 2,000 psig (637F) may be involved in thermal oil recovery projects, a solubility study was conducted between 482 and 617F.' Discussed in this paper is the application of these data to the prediction of anhydrite precipitation in some practical steam soak and hot-water injection projects. Any simple method for predicting the solubility of an inorganic compound over a wide range of temperatures and solution compositions must be based on some assumptions, and therefore must yield approximate results. On the one hand, natural brines contain too many ionic species for all to be included in a simple scheme; on the other hand, there is no adequate theoretical basis for the exact prediction of solubility in even simple solutions of mixed electrolytes. However, it is possible at a given temperature to base a reasonable prediction scheme on two phenomena:'-' the increase in solubility with increasing total concentrations of all ions (as measured by the ionic strength; see the Appendix), and an increase due to formation of cornplexes between calcium ions and sulfate ions and between sulfate and magnesium ions. Stiff and Davis' developed such a scheme for predicting the solubility of gypsum (CaSO, ¦ 2H,O) in brines at temperatures u~ to 212F. However, for the higher temperaturei of present interest, the stable solid phase is anhydrite (CaSO,). This study involves a two-part method for predicting anhydrite solubility products. First, one predicts a value K, for a given ionic strength I and a given temperature T corresponding to mo./msr, = 1 from data of the CaS0,-NaCI-H,O system. Second, one determines a group of factors F .= F(Ca) • F(Mg) • F(SO,), where the individual factors account for increases in the solubility product due to complex formation by high concentrations, respectively, of calcium, magnesium and sulfate. Combining the two parts, one obtains the solubility product in molalities as

Jan 1, 1969

THE discussion of this topic at the Open-hearth Conference at Detroit on Nov. 3, 1927, was opened by statements of the general principles involved, made by manufacturers of molds. Because of their general interest they are printed below. WILLIAM HAIL RAMAGE,* Hubbard, Ohio.-I did not come prepared to read a paper, thinking. the most I would be called upon to do would be to make a few, remarks by way of discussion. A number of our friends have pre-viously asked questions. similar to this which really does not permit a direct "yes" or "no" answer. If I may he pardoned for so doing, I believe it advisable to discuss rather what we consider the principal factors which in-fluence mold life. I think possibly a little undue weight has been given to the subject of the analysis of the metal. For the last eight years we have spent a lot of time, effort, and money investigating this very problem from a chemical, physical and microscopic standpoint. We have had the benefit of complete records and history of over 100,000 molds in service at a variety of plants and over long periods of time. Obviously, I cannot be so specific that I should divulge information that is really a trade secret. In our opinion the principal factors influencing mold life are: (1) design of the mold; (2) process of manu-facture, including workmanship; (3) care in the steel plant or what might be termed "the use or abuse" in the steel plant; (4) the analysis of the iron and the physical con-dition of it. Under normal conditions these factors are of importance in the order named, although in specific cases they might be rearranged in any order you choose. For instance, the best mold made can be destroyed in one or two pours by subjecting it to certain conditions which are occasion-ally met in steel plant practice. Obviously, in that case, nothing else matters but that one item. On the other hand, I have seen molds made of such a terrible design that it was a foregone conclusion it would have to be broken after the second pour of the ingot to get it out. In that case, nothing but design mattered. As to the effect of process of manufacture, let me cite a case. Some years ago there were two batches of molds sent to a certain company. They were the same sized molds, used under the same conditions and in the same kind of service. There were, 20 molds in each batch. The second batch sent gave ten times the life of the first batch. It is true that the design was changed a little, but not very much, and it was not. a bad mold to begin with. It is possible that the iron may have been better in the second consignment but not very much. In my opinion, it is con-servative to say that of the 900 per cent improvement in life, 5 per cent was probably due to better iron, 25 per cent to better design and the remaining 870 per cent to process of manufacture and workmanship.

Jan 2, 1928

By K. S. Lane

As the initial chapter in this section entitled "Role of Fluid Pressure in Rock," this attempts to fulfill an assignment for (1) summarizing the state-of-the-art and (2) illustrating engineering problems resulting from rock pore pressure. Hence, the chapter is presented in two parts: 1) Basic Concepts, and 2) Examples of Engineering Problems, including failures. Neither of these objectives has necessarily been completely met: partly from limitation of space and partly as the case histories have been restricted to the author's own field in civil engineering, and there deemphasizing those applications which will be covered in more detail by subsequent papers in this section. As with any state-of-the-art attempt, contributions of some have undoubtedly been overlooked (or omitted for brevity). Notwithstanding the foregoing limitations, it is hoped that this summary of the situation will at least: 1) Outline current concepts on effects of fluid pressure in rock-both as a pore pressure in interconnected void spaces of the intact rock and as a cleft pressure or hydraulic force acting in the joints or other discontinuities of the rock mass. 2) Indicate the often fragmentary nature of evidence presently available to support these concepts and thus encourage further research. 3) Illustrate the major significance of fluid pressure in several types of engineering problems and thus stimulate its consideration as designers encounter related situations.

Jan 1, 1970

By ir. H. Eraly

The allocation of miners to teams, and of teams to production faces, is complicated by the high degree of absenteism of miners in Belgium. Therefore, the exact knowledge of who is actually present at the beginning of a shift and of the exact skills of those present, enables the foremen and mine captains to constitute their teams before all men go down into the mine in the most effective way possible. This paper describes the system of attendance recording and of displays which the foremen use to constitute their teams and/or to interrogate the personnel data base in order to do so. It shows how the foremen dialogue with the computer, to change the function of a miner within a team, to another team, or the function of a team as a whole. The implementation of the system, data bases, and data communication equipment and procedures, is described. The benefits obtained are presented for each level of the company: foremen and team supervisors, engineers, mine management.

Jan 1, 1977

By R. H. Martinson, E. Teghtsoonian

The effects of magnesium-rich surface layers of varying thickness on the mechanical properties of LiF have been studied. The yield stress, critical tensile stress, and work-hardening slope increase linearly with layer thickness, while the strain to fracture decreases yapidly with increasing layev thickness. The results of tension tests, supplemente!d by metallogvaphic evidence, indicate that the yield stress and the critical tensile stress of LiF are not determined by surface-source operation. DESPITE many studies, which have recently been reviewed,' certain fundamental aspects of the plasticity of LiF remain obscure. For instance, one question still awaiting a satisfactory resolution is: does the nucleation and/or multiplication of dislocations in LiF occur preferentially near the crystal surface? It is now well-known that mobile dislocation half-loops are readily introduced into LiF by surface damage and that the mechanical properties of LiF are affected by such surface damage. However, it is not known whether, in the absence of large numbers of artificially introduced surface sources, dislocations arise more easily near the crystal surface than in the crystal interior. It is also not known to what extent existing mobile dislocations multiply preferentially near the crystal surface. The present work is an experimental study of these matters. A short investigation of the effect of magnesium -alloyed surface layers on the deformation of LiF single crystals has been published by Westwood.~ Some relevant conclusions drawn from this research are restated here for purposes of comparison with the present work. 1) Tests on as-cleaved, chemically polished, coated and uncoated specimens show that a coating can restrict the operation of artificially introduced surface sources, thereby raising the yield stress. A coating also decreases the initial rate of work hardening of as-cleaved LiF crystals by reducing the number of active dislocation sources, so that mutual dislocation interference effects are lessened. 2) A catastrophic breakthrough of groups of edge dislocations piled up against the coating can cause stress drops in the stress-strain curve. 3) A surface coating can act as a stable barrier to the egress of dislocations, causing pile-up,

Jan 1, 1965

By E. B. Swanson

There is only one way to transport natural gas and that is by pipe lines. In the past few years, these lines have been extended rapidly into areas which previously had been served mainly by solid and liquid fuels. In the subject given me, this extension is referred to as an invasion, which implies a rather forceful entry. Whether or not such an implication may be applied to recent natural-gas developments is unimportant. It is the fact of the extension, not its definition, which is important. For centuries, natural gas has been utilized for various purposes in many parts of the world. It was the foundation of fire worship at Baku. The Chinese used it for the evaporation of brine in salt manufacture. In our country, its history seemingly dates back 110 years to the vicinity of Fredonia, N. Y., where seepage gas was assembled and used for lighting purposes. A few years later, a %inch pipe was laid to a lighthouse on Lake Erie, and the early records of the Lighthouse Service tell of the difficulties surrounding this use. With the discovery of oil in Pennsylvania, there followed further development; the town of Titusville was piped with natural gas and, some few years later, gas was made available for manufacturing plants adjacent to the oil fields. For more than a half century, the industry was concentrated in the

Jan 1, 1932

Jan 1, 1900

By F. L. Sizer

SOME old-time views which have recently come into my possession have inspired me to record that part of the early history of Leadville, Color- ado, with which I am familiar, the years 1878 to 1882, in the hope that others will add to what is here mentioned. My first appearance in Leadville was in June, 1878, immediately after graduation from the University of Michigan, and I found a congenial and lively crowd of young men, already there. The old log hotel, at the corner of Pine and State streets, housed some distinguished guests in the summer and fall of 1878. It was my good fortune there to make the acquaintance of James B. Grant, afterwards Governor of Colorado, in July of that year, when we were both glad of the accommodation afforded by cots in the second floor loft of the hostelry presided over by Herman Hibschle. Grant was then building his smelter and our associates were Eddy and James, August R. Meyer, and Berdell and Witherell. The Grand Hotel-Harris and Walsh, pro- prietors-was the first-class hotel of the place; but in a very few months there were many competitors.

Jan 1, 1924

By L. S. Birks

The bainite transformation in a 3.5 pct Ni-1.25 pct Cr steel was studied under various conditions of cooling and stress. Several characteristics may be specified: 1) transformation in the bainite region (925° to 575°F) is very little affected by the manner of cooling from the austenitizing temperature at 1600°F to 575°F)tothe upper limit of bainite transformation at 925°F; 2) starting time for the bainite transformation is the same order of magnitude for either isothermal transformation or continuous cooling, but the rate of transformation is somewhat greater for isothermal transformation; 3) tensile stress accelerates both isothermal and continuous cooling transformation, and 32,000 psi stress changes the form of the isothermal transformation diagram to correspond in appearance to the continuous cooling diagram; 4) transformation for nonlinear, continuous cooling may not be determined directly from the linear, continuous cooling transformation diagram, but may be predicted by assuming first that the fractional amount of austenite transformed in a given small temperature interval depends on the approximate linear cooling rate during that temperature interval and then by summing stepwise over the whole temperature range. IN a previous publication' an X-ray spectrometer was described with which the X-ray diffraction from a specimen could be observed continuously under controlled temperature and tensile stress. This instrument has now been applied to a study of the austenite-bainite transformation in a Ni-Cr steel for both isothermal and continuous cooling conditions, with and without stress. Certain characteristics of the transformation lead to a method of predicting the amount of transformation to be expected at a given temperature for any type of cooling curve. Material and Specimen Preparation The steel chosen for the investigation was a Ni-Cr steel having the composition in the following percentages: 0.30 C, 0.27 Mn, 0.019 P and S, 3.50 Ni, and 1.25 Cr. In order to fabricate specimens suitable for the X-ray spectrometer, a 1/4 in. plate was ground down to 0.060 in. and then cold rolled to about 0.035 in. Next it was heat treated by quenching in oil from 1650°F and tempering at 1200°F for 1 hr. Then it was etched in dilute nitric acid to reduce its thickness to 0.014 in. and cut into blanks in the shape of flat tensile specimens 3 1/4 Vi in. long, 7/16 in. wide, with a notch % in. long and 7/32 in. wide; see Fig. 1. X-Ray Technique Since the X-ray spectrometer has been described in detail elsewhere,' only a brief outline of the principles will be repeated here. A focusing, pow- der-diffraction arrangement' was used, as shown schematically in Fig. 1, and the specimen was mounted vertically in a vacuum furnace (not shown in the figure). The X-rays, moving in a horizontal plane, enter and leave the furnace through beryllium windows. As shown in the figure, X-rays diverging from the line source A are diffracted by the specimen B and converge at the detector slit C. The detector D and the slit C may be set at the proper angle in the horizontal plane to receive X-rays diffracted by either the face-centered phase (austenite) or the body-centered form (ferrite, bainite, martensite). The specimen is heated by electrical conduction between connectors E, and E,, and a Pt—Pt-10 pct Rh thermocouple spot-welded to the center of the notched region on the side away from the X-ray beam indicates the temperature continuously on a Brown recorder. Temperature control is exercised manually with a variable transformer on the input to E,-E,. Any desired time-temperature relationship is easily obtained by first drawing the desired curve on the temperature recorder chart and then adjusting the variable transformer during the run so that the thermocouple

Jan 1, 1957

By J. L. Workman

The Putnam Coal Mine, at design capacity, will be the third largest underground bituminous coal mine in the world and will feature the world's longest single flight belt conveyor. Construction is now in process; initial mining will commence in early 1969 and design capacity will be reached in 1971. The Putman Coal Mine reserves are located in south-central West Virginia and contain approximately 27,000 acres of prime Pittsburgh No. 8 coal; reserves are sufficient to support a 3.5 million tpy operation for over 30 years. The mine portal area is located some six miles inland from the Kanawha River. The river loading facility is located approximately 156 miles by way of river from the market.

Jan 1, 1969

By W. O. Philbrook, C. W. McCoy

The reduction of chromous oxide from lime silica alumina slags by carbon-saturated iron behaves as a first-order process having a rate of 0.001 grams Cr min 1 cm 2 (pct Cr ) , substantially independent of slag composition and temperature over an important range for iron smelting. The equilibrium ratio (pct Cr)/[pct Crl is below 0.04 for slags having lime-silica ratios above 0.6. MANY studies have been conducted on chromium in slag-metal systems under oxidized conditions. The Purpose of these investigations has been twofold; namely, (1) to determine those conditions which lead to greater chromium recovery in electric-furnace and open-hearth practice, and (2) to determine the nature of oxide inclusions and de-

Jan 1, 1959