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By AIME AIME

NO FEATURE of the annual meeting is considered more important at Institute headquarters than the assembly of delegates from the various local sections and divisions. There the president of the Institute and other officials may learn at first hand what the members are thinking and doing in every part of the country, and the delegates, in turn, may find that head- quarters is not a group of more or less cold-blooded New Yorkers whose primary function is to send out annual bills for $15. This year, the section and division delegates required three sessions to thresh out the matters of common interest: Monday morning and afternoon and Thursday afternoon. They were also guests of the Institute at the Directors' dinner on Tuesday night, and at the Directors' meeting afterward.

Jan 1, 1932

By Albert Stazicker

AT Climax the warehouse department operates as an independent unit similar to the mine and mill departments. It has the responsibility of receiving, checking, unloading, and storing all material and supplies delivered to the plant. In addition, the transportation of all supplies comes under the direction of the warehouse so that prompt delivery of supplies to all departments is one of its major functions. The transportation division operates heavy and light trucks, trailers, two large tractors, and two snowplows. In addition to delivering supplies it is also responsible for snow removal from the roads, hauling of sand and gravel for concrete and domestic coal to employees. and all miscellaneous work involving the use of tractors or trucks.

Jan 1, 1946

By Augustus Locke

San Francisco Meeting, October, 1911.) Two Opposed Interpretations of the Tonopah Structure.-The important geological publications concerning the Tonopah mining-district are those of Spurr 1 and of Burgess.2 In these publications are presented fundamental differences of interpretation, which are the more interesting because both authorities have had ample opportunity for observation, and because both are geologists of proved ability. I was vastly puzzled to know which had the better of it, and in order that I might reach a conclusion in my own mind, I recently spent some time in the district going over the physical evidence. Surprising as it may seem, this evidence looks agreeably conclusive. A review of it will, I believe, be of interest to those who are familiar with the previous publications. The general geological features of Tonopah are shown in Fig. 1, and the differences of interpretation referred to are outlined in the accompanying notes. Briefly, Burgess regards the various rocks as flows, lying in the order of their deposition. Spurr regards them in part as flows, and in part as flat-lying intrusives. The disagreement, then, concerns the rocks regarded on the one hand as intrusives, and, on the other hand, as flows. These rocks are chiefly the so-called calcitic andesite, the upper rhyolite, and the lower rhyolite. Economic Importance of the Question of Interpretation.-The economic importance of the question of interpretation is, of course, limited to its bearing on the probable distribution of 1 Geology of the Tonopah Mining District, Nevada, Professional Paper No. 42, U. S. Geological Survey (1905). Report on the Geology of the Property of the Montana-Tonopah Mining Co. (1910). An abstract of this report is given in the Mining and Scientific Press, vol. cii., No. 16,p. 560 (Apr. 22, 1911). 2 The Geology of the Producing Part of the Tonopah Mining District, Economic Geology, vol. iv., No. 8, pp. 681 to 712 (Dec., 1909).

Feb 1, 1912

By E. C. Rien

When the electrical system for a surface or open pit mine is designed, four major considerations should be satisfied in the following order: safety, reliability, flexibility, and cost. Careful planning initially will make expansion for future growth economical as well as possible without extended shutdown of operations. Electrical requirements in surface and open pit mining can be divided into three categories: main substation, plant power, and pit distribution. These systems are integral to each other, but will be dealt with separately here. 11.2-1. Main Substation. A main substation for a mining operation may vary from a 500 kva transformer supplying 480-v power to motor-driven pumps and conveyors, to a 50,000 kva substation serving a large beneficiation plant or a large strip mining operation. Regardless of size, it should be designed with the realization that a failure of the main substation will totally shut down the operation (Fig. 11.2-1.). Location of a main substation usually is a compromise between expense of running the incoming high-voltage transmission lines and the voltage drop of long secondary runs. Based on a geological survey for immediate and future areas of excavation, the main substation should be located as near to the center of load as possible. The site should be out of the blasting area, readily accessible to authorized personnel, and situated where prevailing winds will keep it free from dust or snow. DISCONNECTS AND OVERLOAD PROTECTION. The main substation should have a primary disconnecting device-either a pole top gang-operated switch and fuses of adequate interrupting capacity or, preferably, an oil circuit breaker with properly coordinated relay protection.

Jan 1, 1968

By D. Harrington

ONE of the main functions of the United States Bureau of Mines is to obtain and disseminate information that will promote safety in and around mines, and the health and safety of employees engaged in mining. Serious health and safety conditions arising out' of contamination of air in metal mines by dust, fumes from explosives and fires, and absorption of oxygen by timber and other causes, led the Bureau of Mines to cooperate with the United States Public Health Service in the study of dust occurrence and ventilation in metal mines in various parts of the country. Dr. A. J. Lanza, of the U. S. Public Health Service, and Edwin Higgins, mining engineer of the U. S. Bureau of Mines, in 1915, made a detailed study in the mines around Joplin, Mo., their reports1 are now available. In 1916, 1917, and 1918, a similar study was made in the Butte, Mont., region by Doctor Lanza and D. Harrington, mining engineer of the Bureau of Mines; the reports of this investigation will be available soon. In 1919, the study was continued in some of the Arizona mines by D. Harrington, of the Bureau of Mines, and G. E. McElroy and Dr. R. A. Koronski, of the U. S. Public Health Service, the underground work being completed in June, 1920; these reports are now being prepared for publication. In the spring of 1920, the scope of the work was extended, with D. Harrington in charge as supervising mining engineer, and short studies made in the mines of the Coeur d' Alenes in Idaho and around Oatman, Ariz. It is hoped soon to extend the work into mines of California, Nevada, Colorado, Michigan, and Minnesota, and ultimately to other states should the mining companies be willing to cooperate.

Jan 2, 1921

By E. S. Machlin, A. A. Hendrickson

Use was made of a recently developed surface-accumulation diffusion technique to measure the self-diffusivity of edge-type dislocation singular lines (Burgers vector along <110>) in a bent and polygonized single crystal of silver. Two factors are involved in obtaining a number for the diffusivity. One factor, the dislocation-line density, was measured by a microscopic technique recently developed, and the value of the other parameter, the effective "diameter" of a dislocation pipe, was estimated. With these parameters equal to 7.3 X 106 dislocations per sq cm and 10-7 cm, respectively, it was found that the self-diffusivity along edge-type dislocation lines was a factor of about two times the average grain-boundary self-diffusivity. The dislocation-pipe diffusivity is about 7x10-7 sq cm per sec at 450°C. THE possibility of short-circuit diffusion through imperfections in crystals has been recognized for some time. It was only recently, however, that concerted effort has been expended to obtain values of diffusivity for grain-boundary short circuits. The work, for example, of Hoffman and Turnbull1 on silver, Fisher&apos;s&apos; analysis of the grain-boundary dif-

Jan 1, 1955

By John W. Cahn

Tile avevage value of the mean curvature of surfaces in a specimen can be precisely delermined by sitrlple measurements performed on random sections or on 1 vojectiotzs of these surfaces. For surjaces enclosing particles, the quanlity is sllown to be velated to the probable tlurrrhev ot particles intevcepted by a random platne and, under certain conditions, to the perimeter of their Projected image and to the increuse in surjace area when the particles grow. Many of the velalionsl~ips are valid for any shape or size of the particles. THE recent growth of the field of stereology or quantitative microscopy is largely the result of the discovery of a limited number of rigorously defined geometrical parameters that can be precisely measured on random sections or projections of a structure without assumption about particle shape.&apos; Such parameters have been the volume fraction and surface area and line length in a unit volume. The present paper introduces the average of the mean curvature of surfaces in a volume, and shows that it can be rigorously measured by counting methods alone. AVERAGE CURVATURE ON A PLANE Consider a curve y = v (x) on the xy plane. The curvature Kp in the plane at any point is given by Kp = (dZy/dx2)/[1 + (dy/dx)2]3/2. The average curvature along the curve may be defined as Kp = (1/L) fKpdl |1] where dl = [(dx)&apos; + {dy)2]1/2 is the length of an element of the curve and .(dl = L is the total length of the curve. The integral on the right-hand side of Eq. [l] will be called the total curvature, It is dimensionless and readily evaluated by substituting d = arctan (dy/dx) to give ah which is the change in direction of the tangents to the ends of the curve, Fig. 1. Hence, Kp = (1/L)(?h) [2] It can also be seen that Eq. [2] is applicable in the limit of sharp corners. Even though the curvature is infinite at a corner, f Kpdl remains integrable and equal to the change of angle. The signs of the quantities Kp and dl are arbitrary and, if the areas adjoining the curve are equivalent, there seems to be no compelling reason to fix the signs. For a closed curve, however, it becomes worthwhile to use the signs to distinguish among different types of areas or phases enclosed. For such a closed curve AO = t2r and As a convention, we shall take the direction of the integration along the curve in such a way that the area or phase under consideration (henceforth called a) is kept to the left side of the curve, Fig. 1. Then Kp is positive where the curve is concave and negative where the curve is convex. For a closed curve Ad - +2n if the curve encloses a, and Ad = —2n if the curve is surrounded by a. PLANAR SECTIONS OF THREE-DIMENSIONAL STRUCTURE OF ISOLATED a PARTICLES Consider next a planar section of a microstructure containing particles of a in a matrix. We place no restriction on shape of connectedness of these particles, and begin by considering the curvature of only the boundary between a particles and matrix&apos; Clumps of contiguous a particles are then treated as a single a particle. The two-dimensional section will show in a unit area na simple closed curves enclosing a particles and nh closed curves of holes, in-

Jan 1, 1968

By N. Standish

By contrast with viscometry and sedimentation, no actual measurements of the applicability of Stokes&apos; law to steelmaking have ever been reported; instead, the proof for and against Stokes&apos; law has been inferred from the frequently observed phenomenon that inclusions collect in the top scum and the bottom of ingots. As such proof is unsatisfactory, continued reference to Stokes&apos; law in steelmaking, even as a model for calculating the terminal velocities of rising inclusions, should be avoided. In fact, all conclusions that have been reached regarding size, density, and viscosity on the flotation of inclusions could be made more rationally without Stokes&apos; law. A worthwhile exception is that of Mitsche1 who in 1934 used Stokes&apos; law to show not only the expected effects of size, density, and viscosity on flotation but also the beneficial effects of i) melting under a slag layer (now Electro Slag Refining); ii) treating melts with synthetic slags (Ref. 2 gives recent applications); iii) bubbling an inert gas through the melt (recent applications in Refs. 3 and 4); and iv) altering the solid/ liquid interface characteristics. At this point, it should again be emphasized that the boundary conditions for which Stokes&apos; law was derived place enormous restrictions on the law but its application, as noted earlier, can yield useful results in some fields under certain conditions and within well-defined limits. When compared with inclusions, which may be solid or liquid, spherical or irregular, dispersed or coagulated, interacting between themselves and the melt, floating in a liquid which is in a state of motion of varying intensity5 and contained in vessels of various shapes and sizes that may change with time as in a solidifying ingot, the conclusion is obvious-Stokes&apos;

Jan 1, 1969

By S. E. Buckley, M. C. Leverett

THE production of oil is accomplished as a result of its displacement from the reservoir by either gas or water, and the amount of oil recovery is limited by the extent to which the displacing gas or water accumulates. This paper describes the mechanism by which the displacement is effected and the advantages of water over gas as a displacing agent. In the light of the results of experimental observations of the flow of mixtures of oil and/or gas and/or water through sands, certain conclusions are drawn relative to the changing character of the displacement as depletion proceeds, and on the effects of the properties of the fluids and of producing conditions on the ultimate oil recovery. INTRODUCTION Crude oil has no inherent ability to expel itself from the pores of the reservoir rocks in which it is found; rather, it must be forcibly ejected or displaced by the accumulation of other fluids. Accordingly, a knowledge of the mechanism by which one fluid is displaced by another is essential to an understanding of the fundamental process by which oil is recovered. The displacing fluids normally available are gas and water, either or both of which may exist originally associated with the oil in a potentially usable form or may be supplied to the reservoir from external sources. Gas is present in most oil reservoirs. If the quantity is relatively small, it may exist originally completely dissolved in the oil, but if the quantity exceeds that which may be held in solution by the oil at the prevailing pressure, the excess will be found in the free state. Most reservoir sands appear to contain some water,1 and in the majority of fields the oil is trapped in the structure and held over water. In certain conditions the entrapping water may advance into the oil zone and displace the oil therefrom. This paper describes in a qualitative manner some of the characteristics of the displacement of oil by either gas or water, with an attempt to elucidate somewhat the mechanism by which such displacement is effected. ROLE OF DISSOLVED GAS When the pressure on an oil containing dissolved gas is reduced to the saturation or bubble-point pressure, gas escapes from solution and expands, imparting to the oil-gas mixture a high degree of expansibility and causing it to flow in the direction of reduced pressure. This expansibility has frequently been attributed to the oil; closer analysis, however, reveals that as gas escapes from solution the oil phase actually contracts. Hence, it is the accumulation and expansion of the liberated gas that supplies the propelling force for the oil. It has been shown experimentally2-5 that within certain limits a sand containing oil, gas and water will permit the simultaneous flow of all three; the readiness with which they may flow depends upon the characteristics of the sand, of each of the fluids, and upon the relative amounts of the fluids in the sand. Thus, in the initial stages of production by the mechanism of dissolved gas drive, the liberated gas is present in the sand in low concentration and is unable to

Jan 1, 1941

By O. C. Ralston

Flotation is now commonly practiced in alkaline ore pulps, yet little is known regarding the action of the alkaline solutions on the ore particles beyond the fact that films of oxidized material form. We wish to chronicle our discovery of the presence of soluble reducing agents in alkaline ore pulps of the United Verde, and present some data on lime consumption. During the grinding and flotation of a pyritic ore containing small amounts of ferrous sulfate and other soluble salts, an excess of lime was added to precipitate the salts, and filtered samples of the solution were titrated with standard permanganate solution. Even in pulps of high causticity an appreciable permanganate titration was always obtained, in spite of the fact that the solutions were shown to contain little iron. Investigation of the cause brought about the discovery of several previously unsuspected compounds in flotation pulps made from pyritic ore. Not only the reducing agents present had to be identified, but also the amount of dissolved oxygen, and a survey was finally made of the free oxygen content and reducing agents of the mill pulp in the concentrating mill at Clarkdale. A great many compounds might form, caused by oxidation of pyrite or other metal sulfides or by reaction between a lime solution and pyrite. The most probable compounds considered were calcium sulfides, polysul-fides, thiosulfates, and polythionates. Later it was discovered in the literature that in alkaline pulp polythionates do not exist and if introduced are decomposed into sulfites and thiosu1fates.l Any precipitated sulfur is changed by alkali into thiosulfate and polysulfide. Sulfites and sulfides react to form thiosulfate, so that in the end it is possible to have in an alkaline solution only thiosulfate and an excess either of sulfide or sulfite. Confirmatory tests were made and it was finally established that the alkaline mill pulps made from the United Verde ore contained

Jan 1, 1930

By F. T. Havard

The present truce in litigation between Western smelting and ranching interests gives opportunity for a summary of the results achieved by metallurgists in condensing fume and de-acidifying furnace-gases. In the absence of complete records of past experiments, there ha&apos;s been a good deal of unliecessary duplication of attempts and failures. Yet, especially uilder the recent policy of our large corporations, looking to the economic recovery of the values of by- and waste products, . original and, in some cases, effective measures have been developed by American metallurgists. In the case of Bliss us. the Anaconda Copper Mining Co., the Montana Suprenle Court, recognizing the progressive efforts made to render the flue-gases innocuous, and the value to the community of the smelting company&apos;s operations, refused to hamper its work, and returned a verdict in favor of the defendant. In the trial, the experimental farms of the company ill the so-called "aff&apos;ected region" were proved to be thriving perfectly, showing that immunity was guaranteed to vegetation and stock by tlle wide distribution of the sulyhurous acid gas in the dry air of Montana. Indeed, L. S. Austin has proved that by the time the fume is 4,000 ft, distant from the stack, the percentage of sulphurous acid has been diminished from 2.28 to 0.00045; and Angus Smith has shown that rain must contain 40 parts per million of free acid before vegetation is affected. The arsenic in the stack-gases is but a very small part of the original content of the ore, of which 80 per cent. and over is rejected in the coilcentrator and furnace waste-products or recovered in the flues, Nevertheless, neither the peace in Montana nor the armistice

Jan 1, 1911

By F. J. Longworth

For a number of years an intensive study has been made to improve the blast-furnace practice at Copperhill not only as to costs but to provide a good grade of gas for the acid plants. This study, took us back to the fundamentals of successful pyrite smelting; namely, a blast furnace working on a clean sulfide ore, free from fines, and the use of quartz high in silica as a flux. In 1919, the quality of the flux was improved and its effect on the metallurgy was very marked. To improve the practice further, it was necessary to work out some method of treatment for the sulfide fines and the siliceous and refractory ores, other than in the blast furnace. A series of milling tests indicated that these products could be successfully treated by differential flotation, and in 1922 plans were made and a flotation plant built. It was estimated that the flotation plant would deliver to the smelter 40 to 50 tons of concentrates per day; the problem was what to do with these concentrates. It was out of the question to attempt to smelt them in a blast furnace because of the dust losses and, because our practice demands a charge free from fines for satisfactory operation. There is no custom smelter in the vicinity to which concentrates may be sold, pending the time when the tonnage will be sufficient to warrant roasters and a reverbatory furnace. Sintering and nodulizing were investigated but neither method fitted into our scheme of metallurgy. A close study of the converter practice was then made to see if some method could not be evolved to smelt this tonnage of concentrates in a converter without preliminary treatment. At that time, the converter installation consisted of two 12-ft. Great Falls converters, which were handling 12 to 14 per cent. matte. The heat balance of the converters working with 12 to 14 per cent. matte was more than sufficient to smelt the contemplated tonnage of concentrates but the mechanical difficulties. of feeding fines into the Great Falls converter made the use of this type of converter impractical.

Jan 9, 1924

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&apos; 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.&apos; 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:&apos;-&apos; 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&apos; 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

By AIME AIME

ALL sessions of the Mining Geology Committee at the Annual Meeting this year were held jointly with other groups, a plan that seemed to work out to the satisfaction of every one. Certain of these sessions are reported in this issue by others; the ones held on Wednesday are covered here. Ten papers, as published in the February M&M, were on the program for the Wednesday morning session, held jointly with the Society of Economic Geologists. Mr. Eckel made a brief presentation of his paper, on which there was no discussion, and Mr. Peoples presented that of which he was a joint author. D. M. Fraser then discussed a gravimeter survey for chromite in Cuba, which blocked out some 50,000 tons of ore, and F. G. Wells told of work on chromiferous sands in Oregon.

Jan 1, 1943

By John J. Porter

The requirements of the standard specifications under which Portland cement is sold have materially increased within the past 10 years, but practically all companies are now furnishing cement better than these requirements; in some cases exceeding them by nearly 100 per cent. From a sales standpoint, it is desirable to have a product that is uniform to a high degree and free from occasional quality troubles. A failure in quality, even if it affects only a few hundred barrels out of a yearly output of a million or more, is apt to be talked about in the trade and to affect the salability of the entire output. For these reasons, there has recently been great activity along the lines of quality control and improvement; and some of the most interesting problems of the industry are in this field. From the manufacturing standpoint, the quality of cement is chiefly a matter of uniform and proper chemical composition of the raw mix fed to the kilns plus proper burning in the kilns; the fineness to which the cement is ground, the proportions of gypsum, the method of seasoning, and the like are contributory factors. Uniform chemical composition of the raw mix has been one of the most difficult problems to solve. Most plants will use from 1000 to 3000 tons of rock per day and in but few cases is this material as it lies in the quarry even approximately uniform in composition. The problem, then, is to quarry and mix this raw material in such a manner that every handful passing through the kilns will have practically the same analysis as every other handful. To accomplish this purpose there are two methods of preparation: the wet and the dry. In each process, a stone storage is the first requisite of a successful plant. This storage place may handle the stone before or after crushing; its capacity may vary from two to three days&apos; up to several months&apos; supply, but it should be so designed that it can be filled as desired by the chemist and drawn at such points as will give a mixture of the various kinds of stone coming from the quarry and a reasonably uniform material going to the mill. The size of the storage place and the method of handling should be varied according to the nature of the material.

Jan 1, 1925

By M. Kaufman, D. Rosenthal

IT would be of great importance to our understanding of the phenomena of fracture in metals if a unique relationship could be established between stress and some easily measurable parameter of deformation up to the fracture. It is known that no such relationshir, has been found when the parameter was the mechanically measured strain,&apos; the major part of which is plastic. The present investigation was initiated to determine, among other things, if the X-ray or lattice strain" might be a • For the definition of lattice strain see ref. 2. more suitable parameter. To this end, annealed stress free*&apos; specimens of 61s aluminum alloy were ** Freedom of stress in this particular case means absence of those stresses which can be checked by the technique employed. tested at room temperature and liquid nitrogen temperature (—195OC), by first maintaining the same temperature from the beginning until the end of the test, and then with crossovers from one temperature to the other. Three major factors had to be taken into consideration in designing the specimens and testing equipment. The test setup must allow X-ray pictures to be taken while the specimen is under load (for as much as 2 hr at a given load). Provision must be made for maintaining the test specimen at the temperature of liquid nitrogen as well as at room temperature. In addition, the specimen must be able to rotate to allow the X,ray beam to take in as large a sample of grains as possible, to maintain centering, and to correct for effects of large grains. The final design of the specimen and equipment is shown in Figs. 1 and 2. The specimen and grips are hollow, enabling liquid nitrogen to be poured in through a funnel-container arrangement while the specimen is rotating. The diameter of the specimens at the 2 in. gage section is 5/16 in. with a 3/16 in. diameter hole through the center. A small pilot valve in the lower grip allows a very small stream of liquid nitrogen to escape, thus assuring circulation of the liquid at all times. A low temperature silicone grease-tissue paper packing is used to seal all joints. The specimen is held in the grips by a pin. Spherical socket joints at top and bottom are used to allow for proper alignment. The grips are connected to the thrust bearings by means of plastic couplings to decrease the heat flow. Rotation is accomplished by means of a motor which drives a plastic gear (integral with the lower coupling) through a semiuniversal joint to allow for deforma- tion of the specimen. The torque applied to the specimen is very small. The maximum stress caused by this torque at the highest loads reached was found to be less than 200 psi, The whole unit was mounted in a 10,000 Ib testing machine. An insulation cage was placed around the specimen to cut down air circulation, and consequent frosting of the specimen, and also to reduce radiation and convection heat losses. A narrow window, covered on both sides with a thin plastic materiai allows the X-ray beam to reach the specimen. Thermocouples placed just outside the pilot hole at the lower grip, in the bottom of the funnel container and near the top of the funnel container permitted checks of the

Jan 1, 1955

By H. M. Chance, T. M. Chance

The term &apos;Llow-sulfur coal," as used in this discussion, is limited to coals containing less, or very little more, than 1 per cent. sulfur. For certain purposes it might be advantageous to include coals that contain as much as 1.25 per cent. sulfur, because such coals have been considered as available for making metallurgic coke of fair grade; but the same reasoning might apply to coals containing as much as.1 1/2 per cent. sulfur, if facilities exist for utilizing such coal by admixture with coal containing less sulfur. , In Pennsylvania, it is not possible to define the exact geographic limits of the areas in which coals relatively low in sulfur exist, because variations in the percentage of sulfur occur irregularly and often abruptly. It is not uncommon to find areas, more or less circumscribed in extent, in which the coal is relatively high in sulfur although all the surrounding territory contains low-sulfur coal; and, similarly, small areas of low-sul. fur coal exist in districts where the coal is normally high in sulfur. These generalizations apply, with few exceptions, to the whole area underlaid with bituminous coal in the State of Pennsylvania, and also to each of the individual beds of coal in this state. Pennsylvania is poorly supplied with coals of the low-sulfur class. We find, however, as an offset to this condition, very large areas in which coal ranging from 1 to 2 1/2 per cent. sulfur exists in beds of good workable thickness. This coal, by washing, can be reduced in sulfur low enough to make coke of a high grade. While a considerable tonnage of workable low-sulfur coal remains in the Pennsylvania bituminous districts, it has been necessary to turn to the areas of higher sulfur coal for the supply of metallurgical coke. This utilization of the higher sulfur areas has been made possible either by washing or by selective mining. Washing.—Fine crushing of the entire feed is not generally necessary to the successful washing of Pennsylvania coals. This is due to the fact that the pyrite is rarely finely and uniformly disseminated throughout the coal but is usually confined to high-sulfur benches in the bed or to concentrations on the cleavage planes of the coal. Hence, by graded crushing and sizing it is frequently possible to at once reclaim those portions of the coal bed containing coal that is relatively free from pyrite.

Jan 1, 1920

By J. L. McK. Yardley

There are two general classes of problems in connection with electric furnaces. First, those relating to the best utilization of the electrical power inside the furnace; second, those connected with the bringing of the electrical power to the point where it is to be utilized. Referring particularly to the latter class of problems, many calculations have been made, covering a wide variety of furnaces, to check the electrical capacity and power factor found from test. The following analysis, made for the purpose of determining the maximum capacity and approximate performance of a new furnace, to operate at 160 volts on a 60-cycle circuit, may be of interest. The first characteristic necessary to determine is the inductance, since this is the factor that limits the amount of power which can be put into the furnace. Inductance is calculated from the dimensions of the furnace, according to formulas of the U. S. Bureau of Standardsll as follows. Formula 99, for mutual inductance, is: M = 2l [log 2l/d-1 +d/l] Formula 103, for self-inductance, is: Both of these formulas are approximations which are nearly correct when 1 is great compared to d or R. 1 = length of circuit, in centimeters, d = separation between the conductors, in centimeters, R = geometric mean radius of conductors. For a circular tube, R = the radius of the circle. For a solid circular conductor, R = 0.7788 X the radius of the conductor. For a rectangular conductor, R = 0.2235 X (a + b), a being the length, and b being the width of the rectangle. To calculate the inductance of a three-phase circuit, it is customary to figure the inductance of one leg. In circuits where the three conductors

Jan 1, 1920

By D. V. BURR

THE ORIGINAL HUDSON RIVER TUNNEL. NOT quite forty years ago a man of uncommon character entered New York. He had several hundred thousand dollars earned by railroad building in the Nest. He was not an engineer, but he had ideas of engineering work which he was destined to prove correct.. He introduced new ways of tunneling, but his plans had only one distinguishing feature-they were simply interesting as showing how such work could be done; they added nothing to the science, have never been used since his clay, and never will be used again. Engineers of repute ridiculed his proposition ; he was an Ishmael in the profession. But if engineers looked askance at him, he certainly returned their contempt in the heartiest fashion, and had no hesitancy about expressing his views of them individually and collectively. This worked to. his disadvantage when he afterward tried to raise the means to go on with the work. He found that the opinion of engineers was respected by financiers, and that money would not flow contrary to their advice. While his conception of large constructions was distinguishingly original, much more marked was his method of demonstrating the feasibility of, his schemes. In the present clays of great undertakings it is the custom to make the other man pay for the experiments. But the man from the West had other notions of how the thing ought to be done. Having wonderful confidence in his own ability and in his perception of the task before him, he used up all his own money before seeking outside assistance. By building several hundred,, feet of tunnel he proved the correctness of his theory, and the tunnel then dug forms a part of the present tube. The result-he failed to finish the tunnel. He was blind in

Mar 1, 1908

By Lynn C. Jacobsen

Among the unforeseen consequences of the 1973 Arab oil embargo has been a considerable array of new or increased taxes on the so-called energy minerals. These taxes will be the subject of this report. Both Federal and State taxes have been enacted, but I will be concerned mostly with state severance taxes and particularly those on uranium. Severance taxes are considered to include all taxes having the distinctive feature of being applied on a natural resource at the stage of extraction. The tax may be based on units of production or on value, and if on values it may be on gross value or on gross value less either arbitrary or cost-related deductions. The tax has a number of aliases - resource excise tax, conservation tax, privilege tax, mining excise tax, ad valorem production tax, and more - and this makes comparison of tax burdens among states difficult. The windfall profit tax on oil is an example of a severance tax at the Federal level. Severance taxes are an established feature of state tax systems, but they continue to be a controversial issue, and proposals to raise or modify existing severance taxes are regularly submitted to the legislatures of the Western energy producing states. No concensus exists as to what is a reason- able and proper level of severance taxation or to the form it should take. The taxes which have been adopted by the various states reflect the interaction of a variety of interests and the specific circum- stances in each state. What follows is a summary of theoretical, practical, and emotional viewpoints and arguments that surface in any statehouse in which a severance tax bill has been introduced. The New Mexico experience will be heavily relied upon. THE ECONOMISTS Marginal effects. A severance tax which is based on a gross percentage of revenue or on units of production is a constant addition to variable costs, and to the mine operator has the same effect as any other increase in operating costs. The direction of these effects is straightforward: the tax will cause the property to have a lowered present value, to be mined at a lower rate than without the tax, raise the minimum grade that will be mined, lead to lower total recovery, make marginal properties sub-marginal and discriminate in favor of richer, more profitable operations (Lockner, 1965; Steele, 1967). In the short run, production facilities are fixed and imposition of a severance tax will have little effect on production levels. In the longer term, capital is mobile and investment and exploration expenditures will shift from minerals and jurisdictions with high taxes to those with low taxes. Over a considerable range of taxation the effect will be to change the relative position of the taxing state, but an overly optimistic evaluation of the capacity of mineral producers to absorb a tax can bring an industry to a halt. It is generally acknowledged that imposition of high severance taxes on taconite in Minnesota stopped development completely, and that only the adoption of a constitutional amendment limiting the amount of taxes that could be imposed in the future brought the firms back and encouraged them to make the huge investments required (Weaton, 1969). A tax which is a percentage of the net operating income (gross revenue less cash operating costs) does not influence the cut-off grade for recovery nor change the time preference for extraction, and hence, is free of the negative features of the tax applied to gross revenues or units of production. In theory it is a more efficient tax but relative administrative complexity and inherent difficulty in predicting revenue have discouraged its use. The Wyoming severance tax on uranium, which uses grade of ore as well as price in establishing taxable value, is the most cost related, and hence, the most neutral and efficient of the various state severance taxes on uranium. Economic rent. Despite the discrimination and the anti-conservation aspect inherent in most severance taxes, economists generally endorse their use because they are seen as a vehicle to appropriate rents - that is, returns greater than the long-run competitive supply price. Conspicuous examples of supposed economic rents are the returns to oil producers because of the OPEC cartel, the returns of the uranium producers under AEC buying contracts in the 19501s, and the high prices obtained by the uranium producers for contracts entered into in the 1976-1979 period. Mining of coal in the Western states is believed by some to generate huge economic rents because of the OPEC caused increase in price of a competitive fuel (McLure, 1978, p. 261), and possibly because of clean air regulations favoring the burning of low-sulfur coal. In theory, such surplus returns could be taxed completely away without affecting supply. In practice, the situation is more complex (Steele, 1967, pp. 234-236); economic rent of mineral production is an elusive quantity involving as it does replacement costs, and technical and market risk, and it, like beauty or pornography, probably exists mostly in the eye of the beholder. Rent may also be perceived to be present in the upper portion of a cyclic market which also has a downside. Where rent exists, it is almost certain to be short-lived - cartels self- destruct, government subsidies end, competitive adjustments occur - but the taxes imposed to capture it tend to be immortal. There is little doubt that the perception of un- usual and undeserved (obscene) profits in the mid- and late 1970&apos;s was a major factor in the adoption of energy mineral taxes strikingly higher than had been previously considered. At the New Mexico legislature of 1977 supporters of a moderate tax were repeatedly confronted with some variant of the statement, "You can&apos;t expect me to believe that a

Jan 1, 1982