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By J. T. Ryan

SAFETY practice or the elimination of accidents in our coal mines is specifically a problem of management. It cannot be delegated to any governmental agency except that the various coal-producing states do and should have some minimum safety standard laws. However, the legislative method of attempting to control mine accidents is ineffective because of the delay between the necessity and the action. It will always be impossible to keep our various state mining laws up to date; and when the law says you must do a certain thin there is a tendency to do this and no more. Unless the scheme for setting up state regulations is so flexible that when a new hazard develops it can be immediately and adequately covered and the whole responsibility for accident elimination placed undivided on the

Jan 1, 1937

By Andrews Allen

WE all remember when, a few years ago the preparation of coal was nothing but a matter of having somebody at the face or somebody in the railroad car pick out the impurities; also the sizes were generally' made" over a bar screen. Anything that was black was coal; and the only matecia1 picked out was the slate or rock-impurities that could be distinguished by eye or by hefting. This was all right as long. & coal could be sold at. a good price. After all, we are all in business to -make the most money honestly out of a certain acreage of coal and a certain plant. For this purpose what is required is the greatest possible recovery of marketable coal and the highest market price.

Jan 1, 1929

By W. G. Pfann

WHEN a molten zone traverses a long, solid ingot in a level, open boat the ingot becomes tapered. While the taper may be slight after one zone pass, it can be appreciable after repeated zone passes, even to the extent of causing an overflow of matter at the end of the boat. It will be shown here that such matter transport by a molten zone arises from the volume change on melting and that it corresponds in magnitude and direction to the magnitude and sign of the volume change. It will be shown also that the mechanism of matter transport is basically similar to that of solute transport by a molten zone, which has been discussed elsewhere,1,2 and that the two processes can be described by similar equations. Finally it will be shown that matter transport can be prevented by inclining the ingot at a critical angle. Contraction on melting results in forward transport, that is, transport in the direction of zone travel; expansion on melting results in reverse transport. The way in which forward transport arises from the contraction on melting may be seen as follows: At the starting end of a solid horizontal ingot of uniform rectangular cross section of height h., form a molten zone of length 1, as shown in Fig. 1. The height h of the liquid will be h. where a is the ratio of density of solid to that of liquid. Advance the molten zone, at constant length, a distance dx. The volume of solid melted will be hdx; the volume of solid frozen will be Izdx, because the height of the freezing solid will tend to be equal to that of the liquid. The resultant change, dv, in liquid volume will be the difference in these quantities multiplied by the density ratio. Hence the following equation may be used for a zone at any distance x from the origin: which is valid in all but the last zone length in the

Jan 1, 1954

By I. Havenaar

Various methods have been proposed in the literature to calculate the pressure losses in drill-pipe and bit-nozzles, i.e., those parts of the mud-circuit where the largest pressure-losses occur. Very few data, however, are available to check the validity of these proposals. Presented in this paper are the results of pumping experiments with clay-water drilling fluids of different specific gravities and different laminar flow-properties (differential viscosity and Bingham yield value), using pipes of different diameters. In addition, a series of measurements on bit-nozzles is discussed. Two main conclusions may be drawn from this work for the flow through pipes. 1. In the laminar flow region pressure losses can be calculated from the differential viscosity and Bingham yield value of the mud. 2. In the turbulent flow region pressure losses can be calculated with good approximation from a viscosity term which is determined by the volume fraction of the dispersed phase. Calculations making use of laminar flow properties may lead to erroneous results. The effect of temperature on the pressure losses in the case of turbulent flow can be calculated from the change in viscosity of the dispersing medium, i.e., water. The main conclusions determined for the flow through bit-nozzles are that for flow conditions prevailing in the field, the pressure-drops in bit-nozzles are independent of the laminar flow properties of the mud. They are solely determined by the density of the mud and the geometry of the nozzle. INTRODUCTION The last decades have witnessed a steady increase in the depth of oil wells. This is illustrated by the increase in the drilling depth record in the USA from 8,046 ft in 1927 to 21,482 ft in 1953. This increasing depth, together with the experience that high rates of mud circulation and high fluid velocities in the bit-nozzles enhance the rate of drilling, has emphasized the importance of selecting suitable mud-pumps when starting the drilling of a deep borehole. For such a selection it is necessary to be able to calculate the pumping pressures necessary to obtain the required circulation rates. The main part of the pressure-losses in the mud circuit occur in the drill pipe and the bit-nozzles. Various methods have been proposed in the literature to calculate the pressure-losses in the drill pipe1,2,3,4. These methods do not all lead to the same results, and at the time this investigation was started insufficient basic data were available to check their validity. Moreover, to our knowledge, no data are available at all on the effect, if any, of the flow-properties of the mud on the pressure-losses in bit-nozzles.

Jan 1, 1955

By M. A. Bryant, J. C. Goodwin, T. B. Faddies, L. D. Kornze

The Mercur Gold Mine is located 56 km (35 air miles) southwest of Salt Lake City in north central Utah; In July 1981 Getty Mining Company made the decision to put Mercur into production. The first gold bar was poured in April 1983. This paper provides details on: 1) the history of the camp, 2) past production, 3) geology of the deposit, 4) the exploration and development program, 5) ore reserve estimates, 6) detailed geologic pit mapping, 7) production blasthole sampling techniques and 8) the use of geostatistics (kriging) in handling assays and gold extractions to produce the required mill feed.

Jan 1, 1985

By Frank L. Nason

RECENT explorations with a diamond-drill, originated and conducted by Mr. J. A. Van Mater, Superintendent of the Lehigh Zinc and Iron Company, have revealed some very important geological facts, which, it is believed, will be of special practical interest to mining engineers. During these explorations the writer was frequently called in consultation, and hence the facts here recorded are almost entirely the results of personal observation. The franklinite-deposit upon which the explorations were conducted has a long continuous outcrop. Figs. 1, 2 and 3 give a map and sections. Beginning at the extreme southern point,

Jan 1, 1895

By G. Purcell, S. C. Sun

In an attempt to determine the relative collecting ability of 18-carbon fatty acids, studies were performed on rutile in aqueous solutions of the fatty acid soaps. The preceding article reported the electro-kinetic properties; this article outlines the flotation behavior. Results of these flotation experiments are described and correlated with the electrokinetic results. Recent studies of the electrokinetic1-4 and the electrochemical5,6 properties of a few solid-liquid interfaces have provided a better understanding of the flotation process. A number of investigators have attempted to determine the relative collecting ability of 18-carbon fatty acids, but their published results (even for the same mineral) vary widely. Such lack of agreement indicated a need for further investigation. In an effort, therefore, to resolve the problem, electro-kinetic studies were made on rutile in aqueous solutions of the fatty acid soaps. Following the determination of the electrokinetic properties, the flotation behavior of rutile was studied. Results of these flotation experiments are described in this paper and are correlated with the electrokinetic results. MATERIALS AND EXPERIMENTAL PROCEDURE Materials: Pure -28, + 35-mesh rutile crystals were used for all flotation tests, and nitrogen-saturated conductivity water was used throughout. Sodium hydroxide and hydrochloric acid were added for pH regulation. The methods of purification for these materials and the preparation of the soaps have been described elsewhere. 7 Equipment: A Hallimond cell, constructed in a manner similar to that described by Fuerstenau, Metzger and Seele,8 was used for the flotation of mineral particles; however, a coarse pyrex frit was substituted for the capillary. Procedure: Purified nitrogen was led through a two- way stopcock into a graduated cylinder partly filled with water. The gas forced water from the cylinder back into a header tank until the water level in the cylinder coincided with a predetermined mark. Reversal of the stopcock then allowed water in the tank to force nitrogen into the cell until the water in the graduated cylinder rose to a second predetermined mark. In this way a constant volume of nitrogen under practically constant pressure was used for each flotation test. However, the flotation time varied, depending upon the amount of mineral floated and the pH of the solution. Rutile crystals were transferred under water from a storage bottle by a glass scoop holding 1.7 g. Consistency of the scoop samples was good, varying from a low value of 1.67 to a high of 1.74 g. The water added to the conditioning bottle during mineral transfer was drained off, and then 2 cu cm of either hydrochloric acid or sodium hydroxide were added. The concentration of pH regulator was adjusted to give approximately the final soap solution pH that was required. The order of addition of reagents did not affect the results within the limits of experimental error. Soap solution of the required concentration was added under nitrogen pressure to fill the bottles completely. Conditioning for 1 hr was carried out on rolls rotating at 35 rpm. After conditioning, 2.5 cu cm of solution were run off into the container of a Beckman (model G) glass electrode pH meter. The electrodes were rinsed in this solution, which was then discarded, and 2.5 cu cm more were added for pH determination. The remaining solution and the mineral were transferred to the cell; care was taken to ensure that all mineral was washed out of the bottle by the conditioning solution. With the cell back in its flotation position the liquid just reached the desired level, and the test was started immediately. The amount of agitation in the cell was kept constant, and flotation was carried out without the use of a frother. In each series of ten tests one was run with no collector added to ensure that the mineral had not become contaminated, and two were conditioned at the same pH to check reproducibility. After each test the cell was dismounted, soaked in cleaning solution, washed in hot water and then rinsed with distilled water.

Jan 1, 1963

By H. Landsberg

In a previous report1 it was pointed out that a successful attack on roof troubles has to be preceded by extensive scouting. As Lord Kelvin once said, scientific progress can be made only if accurate data are available: "unless you measure, you do not know." The Convergence Recorder For the observation of roof movements in mines the convergence recorder has shown that it will enable us to get some of the necessary information. Results with convergence recorders were first published by Winstanley and other English investigators for rapidly moving longwall faces. In their investigations the speed of work and the heavy overburden produced a considerable amount of absolute values of convergence in a short time. Under the conditions frequently encountered in our investigations in Central Pennsylvania, under shallow, overburden and in mines with slowly proceeding extraction, the movements observed were much less in absolute value, for an equal interval of time. This mas partly because the mines in which our studies were carried on frequently had idle days, sometimes four or five in succession. Therefore continuous records were not employed and a simple convergence gauge was built. In its first models, it consisted only of two telescoping tubes pressed against roof and floor by a coil spring. At the side of the lower tube a rule divided into 1/2-mm. divisions mas fixed and a knife-edge, which was attached to the upper tube, mas slid over the scale in case of convergence between roof and floor. While the larger motions could be read on this device, it seemed to be desirable to increase the accuracy by inserting between the two tubes a dial meter reading in 1/1000 in. Such a gauge was first built in April 1937 and installed for experimental purposes in a bituminous coal mine in Pennsylvania (Fig. I). It was read at least once daily, 24 hr. apart, and if feasible at shorter intervals. After several months of experience it can be said that this type of gauge answers the scientific as well as the practical needs. It is easier to handle than the recorder; no clock is used, there are no pen troubles. The price of

Jan 1, 1938

By H. Landsberg

In a previous report1 it was pointed out that a successful attack on roof troubles has to be preceded by extensive scouting. As Lord Kelvin once said, scientific progress can be made only if accurate data are available: "unless you measure, you do not know." The Convergence Recorder For the observation of roof movements in mines the convergence recorder has shown that it will enable us to get some of the necessary information. Results with convergence recorders were first published by Winstanley and other English investigators for rapidly moving longwall faces. In their investigations the speed of work and the heavy overburden produced a considerable amount of absolute values of convergence in a short time. Under the conditions frequently encountered in our investigations in Central Pennsylvania, under shallow, overburden and in mines with slowly proceeding extraction, the movements observed were much less in absolute value, for an equal interval of time. This mas partly because the mines in which our studies were carried on frequently had idle days, sometimes four or five in succession. Therefore continuous records were not employed and a simple convergence gauge was built. In its first models, it consisted only of two telescoping tubes pressed against roof and floor by a coil spring. At the side of the lower tube a rule divided into 1/2-mm. divisions mas fixed and a knife-edge, which was attached to the upper tube, mas slid over the scale in case of convergence between roof and floor. While the larger motions could be read on this device, it seemed to be desirable to increase the accuracy by inserting between the two tubes a dial meter reading in 1/1000 in. Such a gauge was first built in April 1937 and installed for experimental purposes in a bituminous coal mine in Pennsylvania (Fig. I). It was read at least once daily, 24 hr. apart, and if feasible at shorter intervals. After several months of experience it can be said that this type of gauge answers the scientific as well as the practical needs. It is easier to handle than the recorder; no clock is used, there are no pen troubles. The price of

Jan 1, 1938

By A. P., Svenningsen

ECONOMICAL handling of a minimum of 25,000 tons of minus 3/4-in. ore per day, grinding it to 2 per cent on 65 mesh, and effecting a high recovery of the copper at the lowest possible cost were the principal aims in the design of the new Morenci concentrating plant. Dealing with a tonnage of this magnitude, it is obvious that lost motion cannot be tolerated. When ore is carried on a conveyor an unnecessarily long distance or elevated to a greater height than necessary, or when pulp flows in a launder by a circuitous route thereby losing elevation and distance, we have lost motion which is always costly both from the standpoint of construction and operation. In addition to the 25,000 tons of ore which must be handled, 100,000 tons of water per day has to be carried through the plant in the treatment of the ore. Though water is not so difficult to handle as the ore, the combined tonnage represents a figure which could easily run into a considerable monetary loss per day if all phases of the design were not carefully followed with the idea of eliminating any unnessary handing of materials.

Jan 1, 1942

By A. C. Fieldner

DURING 1939, 286 by-product coke ovens were completed and put into operation. These included 140 Witputte ovens for the Carnegie-Illinois Steel Corp., at Gary, Ind.; 61 Koppers-Becker ovens for the Ford Motor Co., at River Rouge, Mich.; 65 Semet-Sotvay ovens for the Great Lakes Steel Corp., Zug Island, River Rouge, Mich.; and 20 Curran-Knowtes ovens for the Midwest-Radiant Corp. plant at Mitlstadt, Ill. The Millstadt plant is unique in carbonizing a washed coat containing 3.50 per cent sulphur. The gas contains approximately 2500 grains sulphur per 100 cu. ft.; this is successfully removed with sodium carbonate solution by the Seaboard liquid purification process. The coke is intended primarily for use as a smokeless domestic fuel in the city of St. Louis.

Jan 1, 1941

By C. B. Dudley

bas shown us that the railroads of this country can save several milt liohs a par by adopting uniform rail sections, and as unfortunately for him, he cannot patent his idea, it only remains for the railroads to adopt it, and to thank him for his payer. Dr. C. B. Dudley, Altoona, Pa. : 111 rising to close this interestin~ discussion, I want, in the first place, to thank every one who has contributed to it for his full and open criticism. The work tvhich has been done on steel rails, and which has been diwu&e,l here Juring thee two days, was not done to establish any pet theories, nor to make out that any person was great or any person small, but with a sincere desire to get at what is the truth in regard to the wedring capacity of steel rails. There are enormous commercial coneiderations invoIved in this question, and, as I look at the matter, the more honest criticism and fair discussion there is, the Inore likely it is that the truth will appear. Ad first I would like to say that it seems to me very little has been said here upon the main conclusion of the paper, namely, that the softer rails give the better wear. All sorts of side issues have been discussed; but this poiat, which is really the principal one at issue, has been largely ignored, aid I cannot But feel that it still remains unshaken. Witb regard to ohemists end chemical work, there has been considerable said tending to throw discredib on chemists and their work; and while I believe that there have been in the past, are now, and may be in the futnre, a good many poor chemical analyses made, X also believe that chemists are, as a rule, as honest and competent as gentlemen who belong to other professiomc. There are chemisb who are chemists, and who are not chemists. The determination of -manganese has bee* called in question. Now I think the chemist at almost every steel works in the country will tell you that, in his experience, the manganese diffe1.s in different parts of the same ingot. Mr. T. T. Morrell, chemist of the Camhria Iron Company, whom I believe to be s thoroughly competent and hone6t chemist, tells me that he has often found different amounts of manganese in different parts of the same ingot. Come with me to Altoona, and I will take you into the machine shop where steel is king cut aud shaped, and I will show you that it is often necessary to stop the lathe or planer and take a cold chisel to cut oat a hard spot, or else ntn the risk of breaking the tool. This hard spot is simply a pttrt of the syiegel which was not thoraughiy mixed with the ma

Jan 1, 1881

By R. W. Smith

IN the manufacture of portland cement, the basic and fundamental essential is a limestone uniformly rich in calcium carbonate and carrying less than 3 per cent magnesium carbonate. In searching for such a deposit, also having in mind quantity of rock, accessibility and quarrying facilities, the Pacific Coast Cement Co. discovered and developed its present quarry at View Cove on the east coast of Dall Island, Alaska. Dall Island is about 100 miles west of Ketchikan and 650 miles north from Seattle. It is 70 miles in length and 5 to 10 miles in width. The climatic conditions are much more favorable than would be expected. The temperature ranges from zero to 70 degrees. The precipitation is considerably more than at Seattle, although there was less snow during the last season than at Seattle. The island is rugged and mountainous; the vegetation is moss and grass and a large portion is timbered with spruce, hemlock and cedar. Some of this timber has market value. The limestone quarry is about 30 miles north of the extreme southern end of the island. The company acquired 240 acres which contain limestone of remarkable uniformity, the percentage of calcium carbonate being about 95. It is estimated that there is ample recover- able rock on the holdings to supply the cement plant at its maximum capacity for well over 100 years.

Jan 1, 1929

By Horace C. Knerr

It has been shown that the resistance to corrosion of duralumin sheet is greatly influenced by the quenching medium used in heat treatment, or, more specifically, by the rate of cooling during quenching. The severity of corrosive attack after exposure to salt-water spray increases in .the following order: The tensile strength, yield point and elongation are only slightly affected by the quenching medium, as shown in Table 1. Tensile test requirements: yield stress, 25,000 lb. per sq. in. minimum; ultimate stress, 55,000 lb. per sq. in. minimum; elongation in 2 in., 18 per cent. minimum.

Jan 1, 1931

By Larry D. Patts

Section 317(e) of the Federal Coal Mine Health & Safety Act of 1969 directed the Secretary of the Interior to prepare standards under which all working places in a mine shall be illuminated by permissible lighting while persons are working in such places. Section 317(e) further provides that such working places shall be illuminated within 18 months after such standards are promulgated. In accordance with this section of the Act, there was published in the Federal Register for December 91, 1970, a notice of proposed rulemaking which prescribed the illumination to be provided in the working places of underground coal mines. In light of written comments, suggestions, and objections to this proposed rulemaking, the proposedstandards were withdrawn and reproposed in the Federal Register for Wednesday, October 27,-19h. In light of further comments, suggestions, and objections, a public hearing was held on April 4, 1974, and standards were again reproposed and published in the Federal Register for April 1, 1976. Promulgation of the final lighting standards took place on October 1, 1976, which means that the underground coal mining industry must comply with face illumination requirements by April 1, 1978. As mentioned previously, the first proposed rulemaking for illumination of underground coal mines was published in the Federal Register on October 27. 1971. In early 1972, Consolidation Coal Company (Consol) and the United States Bureau of Mines agreed to a cooperative study of underground face illumination: Consol felt that expertise is this field would become increasingly important. Consol's initial efforts in illumination were aimed at investigating practical lighting systems for underground face equipment. We were concerned with installing unobtrusive lights which provided sufficient face illumination for safety, but at the same time were readily maintainable, electrically reliable, and physically sheltered from damage. We believe that our initial lighting systems did provide sufficient face lighting for safety, but because only prototype components were available for field testing, the resultant poor system reliability and maintainability necessitated drastic improvement before face lighting could become practical. Final Lighting Standards Deem Early Lighting Installations Out Of Compliance On April 1, 1976, the Federal Register contained the final version of the illumination standards (as they were later promulgated in October). When these illumination regulations and measurement techniques were defined and measuring instruments were available, Consol checked their lighting systems underground and determined that the systems were not in compliance with these final illumination standards. More Lighting Hardware Added In An Attempt To Achieve Compliance. After determining that all of our face lighting systems were not in compliance, we began adding additional lighting hardware in order to meet compliance with published regulations. Unfortunately, to date, we have not been able to meet compliance with practical lighting systems. We have determined from our field installations that the required additional lighting hardware, (to meet compliance) with its increased vulnerability and decreased reliability, renders the lighting systems impractical, if not impossible, to reasonably maintain. Our attempts to provide 0.06 footlamberts have also produced adverse operator reaction to the glare and to illumination systems in general. BCOA Members Ask MESA To Demonstrate Practicability Of Compliance With Regulations Industry concern about meeting the impending lighting regulations was mounting, and in May of 1976 a meeting between MESA and BCOA members was held to discuss lighting compliance problems. At this meeting, BCOA offered to work cooperatively with MESA in testing the practicability of various lighting systems mounted on underground mining equipment. Field tests were to be conducted by United States Steel Corporation, American Electric Power Service Corporation, and Consolidation Coal Company. The purpose of this underground field testing was to develop capability to provide adequate face illumination in a safe, workable manner which would not detract from efficiency of operation. BCOA members involved in this cooperative study were to submit necessary machine drawings, sketches, etc. to MESA in order that MESA could perform a "black-box" study and specify the type and location of luminaires to be installed on the test machines. MESA was confident that they could specify lighting systems that would be in compliance and would be practical so as not to detract from efficiency of operation. Consol was first to install lighting hardware under the BCOA/MESA cooperative agreement. As per MESA specifications, Control Products HgV luminaires were installed on a Joy 2BT-2H boring machine at the Williams Mine of Northern West Virginia Region. As of mid-October, 1976, Consol had approximately eight weeks operating experience with the lighting system on this boring machine underground and had drawn the following conclusions: The lighting system installed at Williams Mine (1) does not meet compliance with lighting standards as originally proposed by MESA, (2) does not provide illumination in a safe workable manner, and (3) will detract from efficiency of the mining operation due to operational delays. Although Consol has rearranged lights on this boring machine in an attempt to reduce operator objections, a practical lighting system which is "in compliance" has not been arrived at as of this writing.

Jan 1, 1979

By Walter S. Weeks

CONFUSION appears to exist in the discussions of fan testing because engineers do not agree on what energy should be credited to the fan in certain cases, and because certain terms that are used in the discussions seem to have double meanings. The purpose of this paper, therefore, is to discuss the useful energy that should be credited to the fan and the methods of determining this energy, and to suggest changes in nomenclature for the sake of clearness. The instruments commonly used in the measurement of fan pressures are the manometer, the static tube, and the impact tube. The static tube is a tube with small pinholes in it. When connected to one leg of the manometer and placed in the air current with the holes facing at right angles to the direction of the current, this tube causes the manometer to register the static pressure, unaffected by the impact of the air. The impact tube is a tube with an opening that faces the air current. When connected to one leg of the manometer, this tube causes the manometer to register a pressure which is the static pressure modified by the impact of the flowing' air on the end of the tube. If the static tube is connected to one leg of the manometer and the impact tube to the other leg, and both instruments are inserted close together in the air current, the static pressure is eliminated and the manometer registers the impact pressure. The efficiency of a fan is the percentage of the expended power utilized in useful work. The items to be included as useful work are a matter of convention, and as the conventions are not universal I feel that the matter is open to discussion.

Jan 1, 1929

By Benjamin F. Tillson

THE past seven years, and 1937 in particular, have witnessed the return of New Jersey iron mining to a place of importance. Following the World War period, little mining was done for several reasons. The properties were operated by small merchant furnaces whose demand was not sufficiently large to warrant large-scale methods with their attendant low operating costs. Under those conditions, the ore produced could not compete with that from the Great Lakes. However, when on Nov. 1, 1.929, the Alan Wood Steel Co., of Conshohocken, Pa., leased the Scrub Oak and Washington properties at Mine Hill and Oxford respectively, they made radical changes in the mining and milling processes which greatly reduced the cost of production and pointed the way to a renewed interest in mining in New Jersey. The following factors have been advanced as influencing the reopening of New Jersey mines:

Jan 1, 1938

By Niels Hansen

Dispersion-strengthened sintered aluminum products are normally manufactured from surface-oxidized aluminum powder, SAP,' or from atomized aluminum powder.' The powder-blending technique consisting in mechanical mixing of the constituents has been used in the manufacture of numerous dispersion-strengthening alloys, but has never been successfully applied to aluminum alloys. This technique may, however, be applicable if it is possible to produce an unagglomerated mixture of the constituents in the form of fine powders, and the present study was initiated to test this assumption in the aluminum/aluminum oxide system.3 Table I lists the two grades of aluminum powder and the aluminum oxide powder used in the manufacture of the alloys. MD 105 A is an aluminum powder with an average grain size less than 5 IJ., which is isolated from the MD 105 powder by centrifugal separation in cyclohexanol. The aluminum powders and the aluminum oxide were blended in a high-speed blender and then subjected to cold compaction and hot compaction at 550" to 600°C. Subsequently the compacts were hot-extruded with an extrusion ratio of 15 to 1. The alloys were evaluated by tensile testing at room temperature and at 400°C, microscopic examination, and heat treatment at 500°C followed by tensile testing at room temperature. For the purpose of comparison, a commercial SAP quality supplied by Swiss Aluminium Ltd. was tested in the same manner. The tensile data at room temperature and at 400°C are plotted in Figs. 1, 2, and 3 as a function of the weight percent of oxide. The oxide content

Jan 1, 1964

By F. Keller

SOME PHRASEMAKER has aptly said that nature made aluminum light but research made it strong. Research has been a vital element in the past progress of the aluminum industry and its future growth likewise depends upon the application of the results of research. The role of aluminum products in World War II is well known and this metal will certainly be increasingly important in the postwar world. Some of the principal developments in the war years were in the field of high-strength aluminum alloys. New and stronger alloys were developed which enabled designers to get increased speed and performance in our fighter planes and bombers. The aircraft industry will continue to use these new materials for peacetime passenger and cargo airplanes. High-strength alloys will also find structural applications in trucks, buses, trains, ships, and bridges.

Jan 1, 1946

By Andrew Corry

GEOPHYSICAL investigations based on radioactivity have been applied to the earth's crust for the purpose of discovering bodies rich in radioactive substances, or for the location of solutions with high emanation or radioactive-salt content, or for the detection of oil, which, in virtue of colloidal properties, has strong powers of radioactive absorption. RADIOACTIVE SUBSTANCES Radioactive substances are distributed in all rocks, waters, and gases in the earth's crust in small quantities. Granites and similar acidic rocks are richest in uranium and thorium, two chief radioactive substances; yet the quantities present in such rocks are of the order 10-12g., this concentration being expressed in grams per gram of the whole substance per cubic centimeter. In granites the uranium yields, according to Haddock, 3 X 10-12 g. of radium per gram of rock. In basalts the uranium yields 1.19 X 10-12 g. per gram per cubic centimeter. Of thorium the granites yield -2 X 10-5 g. per gram of rock; the basalts, 0.77 X 10-5 g. per gram. Certain series of alkalis of low atomic weight, like potassium and rubidium, show weak radioactivity; this property has no significance so far for geological research. The uranium is esti-mated indirectly from the electrical properties of one of its derivatives as a -gas (emanation) into which it is transformed. The thorium is expressed directly, though it is measured as a derivative, thorium emana-tion. There is a measure for the gaseous radium emanation, the curie, which is that quantity of radium emanation, or radon, which stands in equilibrium with 1 g. of radium. The concentration of the emanation is the Mache unit corresponding to 3.64 X 10-10 curie per liter. When gases become permeated by alpha, beta, and gamma rays, plus and minus ions are produced in them by the decomposition of neutral gas molecules, and under the influence of an electrical field these ions are given opposite motions. The measurement of the alpha rays and the bisection thicknesses of the beta and gamma rays is a means of analyzing unknown radioactive substances. These rays accompany the disintegration of radioactive substances and arise from "spontaneous internal changes

Jan 1, 1929