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By Allen R. Rowen

One of the greatest deterrents to more widespread use of manufactured lightweight aggregate is the fact that no industry-wide standards for its application exist. It is true that ASTM has specifications covering lightweight aggregate, but they are so broad as to be of little assistance in mix design work. Today even an engineer who has worked with one lightweight aggregate may be faced with re-education on his next light- weight concrete job if he is in an area served by another producer. Manufacture of lightweight aggregates has grown with the country, appearing in the patent literature at least as early as 1875, when a patent was issued covering use of burnt clay aggregate as an admixture in manufacture of artificial stone. The widely known Haydite came into the picture prior to 1920 as a result of work by Stephen J. Hayde, and there have been many others since who have contributed significantly to the growth of the industry and its technology.

Nov 1, 1956

POSITIONS VACANT (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) Wanted for a mill on the Ivory Coast of Africa an experienced amalgamator and millman. Salary, $160 to $200 per month. No. 18. ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) Chemist-metallurgist of broad technical training, university graduate, with experience in chemical and metallurgical research work, desires position, preferably in the East. Has successful past that stands investigation. No. 73. Member, mining and metallurgical engineer; thorough technical training, Ph.D., Columbia University, aged 39, married, with-an-extensive experience in smelting, mining, and economic geological work in U. S., Mexico, and South America, desires position as assistant to the Manager or Superintendent, or as a director of experimental and research work, with a reliable mining or metallurgical company. The West, Mexico, or South America preferred. No. 98.

Jan 6, 1914

By L. Mair

A STUDY by J. R. Low, Jr.1 on the effect of quench aging on the Charpy-impact specimens of semikilled 1020 steel disclosed that a decrease in cooling rate from 1275°F raised the transition temperature. This was demonstrated in his investigation by controlling the cooling rate of impact specimens to duplicate that of a heavier plate and com- paring the properties with air-cooled specimens and quenched specimens. The transition temperature of the samples that had been cooled at a rate estimated to be similar to that of an air-cooled 3/4 in. plate was approximately 45ºF higher than the quenched samples. The transition temperature of the air-cooled series was between that of the slow-cooled and the quenched series. On the basis of this work, it appeared that the cooling rate of plates after rolling in a hot mill would have a bearing on the brittle fracture of the

Jan 1, 1955

GWILLIAM H. CLAMER (Philadelphia, Pa.).-About 16,000 tons of tin is used annually in the production of white metals. The real reason for using the so-called genuine babbitt, which is a high-tin base babbitt, perhaps in the majority of cases, is that tin has always been. a high-priced metal and people naturally believe that what they pay a high price for must be good. Mr. Jones has shown that the common metal, lead, is a superior base for most purposes for Which babbitt metal is used. The addition of lead is often looked upon as adulterant to genuine babbitt, and specifications for this reason rigidly restrict the lead content. A sub-committee of the Society for Testing Materials, at the meeting in June, presented tentative specifications on babbitt metal, in which were included twelve formulas, containing from zero to: 20, per cent. of tin, and several containing from 65 and 92 per cent. Babbitts. containing

Jan 1, 1919

By T. A. Boyden

The Free World uranium market is now characterized by production nearly twice that of consumption result- ing in a rapid build-up of uranium inventories. Low- cost production from high-grade deposits in Australia and Western Canada will gradually add another 10 to 15 million pounds U308 annually into Free World production throughout the 1980's. This latter material cannot be absorbed in further inventory build-up and can only displace higher cost production. The result is a restructuring of the Free World producer industry. United States and Eastern Canadian producers have the higher cost production which gradually will be displaced from the market during this decade. As United States production declines, United States utilities must increase their reliance on foreign supplies in order to meet their needs. This paper reviews the elements that will cause the restructuring of the Free World producer industry and the expected response of the United States utility industry to that developing situation.

Jan 1, 1982

By Norman P. Goss

The Chairman.—Thank YOU, Mr. Goss Gentlemen, I believe we have heard one of the finest papers, especially since Mr. Goss has been very generous in his frank discussion of continuous casting. One point he has brought out which 1 think some of us have not thought through to the same extent that he has—that the continuous casting process offers the small producer an opportunity to compete with the larger, more conventional and presumably better established industries. The meeting is now open for discussion. Are there any questions concerning the first two papers? J. A. Malone.*—I should like to ask Mr. Goss whether there is any special problem involved in the first part, the upper part of the mold before he gets to the first graphite lubricant area. N. P. Goss.—You mean in the forming chamber where chilling first takes place? J. A. Malone.—Yes. N. P. Goss.—So far I have not had any trouble in this part of the setup. My only

Jan 1, 1945

By John W. Gruner

On account of the tremendous increase in the production of steel there has been much speculation as to the reserves of iron ore. A number of estimates of world scope have been published, which show that these reserves are definitely limited if a long range view is taken. There are, however, optimists who believe that in perhaps two generations the metallurgy of iron will have advanced to the point where any kind of iron mineral combination of perhaps 20 pct iron will be usable. This thinking has been particularly applied to the new taconite developments of the Mesabi Range, for here is an iron formation of such vast extent that its iron could almost last forever. Let us briefly examine this most favorable of all low grade ore reserves in North America. Nothing will be said about the 1,000 million long tons of material now classified as ore, for they will be largely gone in less than 20 years.

Jan 3, 1954

By Milton Glicken

The airborne geophysicist is a busy man these days. In his plane he may have the airborne magnetometer, the airborne scintillation counter, and the airborne electromagnetic surveying system. Each of these is an independent tool, but all require additional auxiliary equipment for locating the aircraft in space: recording altimeters and Shoran or aerial cameras. Now there is still another piece of equipment, the airborne magnetic gradiometer, an accessory to the magnetometer. To understand its uses, consider the function of the magnetometer itself. Aside from detecting magnetic ore, the airborne magnetometer finds greatest use in spotting intrusions of igneous material. Where there is enough contrast in magnetic susceptibility of igneous rock and adjacent formations, it outlines the intrusion. Certain minerals also influence the magnetometer directly, but with the exception of magnetite and possibly one or two others, their effect is weak and can be detected only when there is sufficient ore and the magnetometer flight passes very close to it.

Nov 1, 1955

By Howard E. Kremers

Since the discovery of the first-known rare earth elements more than a century ago, these metals have always been of academic interest. It is not so well known, however, that a rather stable, respectably large industry based on rare earths and their related materials has been in operation for more than 60 years. Rare earths, of course, are the elements having atomic numbers 57 through 71--lanthanum through lutetium in the periodic table. The most important commercial members of this group are mixtures of the lower atomic-numbered rare earths, and cerium. Although yttrium is not a rare earth, it occurs with rare earths and its properties are so similar to them that. it must be included in a discussion of these elements. In addition, thorium is important to most producers of rare earths because their ores generally contain this element. Thorium extractive metallurgy and technology is closely related to rare earth chemistry due to the frequent similarity of properties.

Jan 4, 1962

By Hal M. Scrugham

UNITED States Steel Co.'s Tennessee Coal & Iron Div. Wenonah mines present definite materials handling problems arising from the natural features of the operation. Trackless equipment went a long way toward supplying the answers-but at the same time gave birth to several new posers. Machines-trackless or otherwise-require maintenance and Wenonah's experience may do much to add to the body of information already available on this type of equipment. Let's look at the mines themselves. Ore is of sedimentary origin, extending over an area of several square miles. A thickness from 8 to 14 ft is mined. Bed dip varies from the horizontal to 20 pct in local rolls. Practice is to mine across the dip at 14 pct or less. A parting forms a smooth footwall in some of the mines while in others the footwall must be blasted smooth. Ore weighs 215 lb per cu ft in place and is extremely abrasive.

Jan 6, 1953

By Whitmell J. Smithwick, Charles E. Dandois

The first operating unit of the ring or annular shaft kiln as developed by Mr. Karl Beckenbach of West Germany was rated 185 tpd and was installed in 1962. Today, there are approximately 84 units in operation in Western Europe and Japan. Twenty-one additional units are under construction or on order. Sizes range from approximately 100-330 tpd, however, units of over 500 tons are in the design stage. The ring shaft kiln is a single vertical cylinder to which are attached the required service platforms, combustion chambers, injectors and distribution piping (Fig. 1). Auxiliaries such as recuperator, exhaust fan and dust collector are mounted on the appropriate service platform. The charging pan, feed conveyor, etc., are mounted at the kiln top and at the bottom of the kiln is the silo with a vibrator type discharger. Mounted separately is the required blower for injector air and fan for internal cooling.

Jan 4, 1973

By Samuel G. Bonasso

The article by Benavides and Schuster provides an in-depth study of this transportation alternatives for a four-mine complex in western Kentucky. The examination of aerial tramways was not undertaken as an alternative solution. We feel this is an oversight since industrial ropeways are competitive with both belt conveyance and overland truck hauling. In fact, there are aerial tramway system, operational today, which are 100 years old and operating with some original components. Maybe unfortunately, there are no fixed rules or guidelines whereby the most cost-effective means of transporting and handling material for a given situation may be selected. Each situation must be evaluated m the variables that influence the selection of the desired alternative can be clearly defined. However, there are in-place industrial ropeway system that have proven economically feasible over a range of 1.6-50 km (1-31 miles). The more difficult the terrain, the greater the cost efficiency.

Jan 1, 1984

Thirteen Directors, the Secretary, and seven guests were present. The formation of a Philadelphia. Section was discussed. The proposed rules for admission of additional societies to membership in Engineering Council were approved. An invitation was extended to the American Institute of Metals to become affiliated with the Institute upon the general terms proposed in the report of the Joint Conference Committee of the American Institute of Metals and the American Institute of Mining Engineers. The request of the Iron and. Steel Committee to hold a meeting in Milwaukee during the week of Oct. 7, 1918, was granted. The reports of the Treasurer and Finance Committee were accepted. A change in the By-laws was proposed. Thirty Members, two Associates, and four Junior Members were elected. The status of two Junior Members was changed to Member. The resignations of seven members were accepted. The clues of two members who are on active duty at the front were remitted. One member was reinstated to membership.

Jan 5, 1918

THE CHAIRMAN (F. K. COPELAND,* Chicago, Ill.).-At this particular time conditions existing in this, country, and elsewhere, make all questions of milling or smelting or mining, or anything else, absolutely secondary to the one question of labor. We have always devoted our attention largely to the efficiency of machinery, and to reductions in costs, etc., and have let this tremendous problem of our relation to labor more or less take its own chances. There has never been a time when those who are responsible for the operation of business of different kinds were as com-pletely at a loss as they are now, so that anything that can be brought out that relates to labor is, to my mind, of utmost importance. T. T. READ, Washington, D. C.-This formulation of a method of curtailing forces at the Copper Queen is a notable step in advance of our treatment of personnel in the mining industry. So far as I know, it is the

Jan 12, 1919

By W. M. Corse

W. M. CORSE,?Mansfield, Ohio.-The conservation of tin, in view of the shipping situation; is one of great importance. Several methods of conservation can be employed: 1. Reduction of the amount of tin in an alloy or compound. 2. Substitution of an entirely different metal or compound for tin. 3. A combination of the first and second methods. The second method is the one that I wish to discuss. Metallic aluminum has been known for a long time, and its use in copper alloys was discovered about 1855 by Lord Percy. The high cost of production of metallic aluminum retarded its commercial development, and it was not until the discovery of the electrochemical processes for its production that it came to be known as a common metal. I have been particularly interested, for the past few years, in working with the alloy known as aluminum bronze, which is usually composed of approximately 90 parts of copper and 10 parts of aluminum, by weight.

Jan 12, 1918

DISCUSSION, A. Y. Bethune presiding M. E. Wadsworth and W. M. Fassell (University of Utah, Salt Lake City)—The authors of this paper should be complimented on the experimental techniques they have employed to investigate the rate of solution of galena in sodium hydroxide solution. Studies of this type are important not only as a practical means of leaching normally non-leachable substances, but also to determine the mechanism of solution at the solid-aqueous solution interface. There is some question, however, as to the conclusions which have been drawn by these authors concerning their proposed mechanism. Unfortunately, the contribution of OH- was not definitely established in their work, and concentrations less than 0.5 N NaOH evidently were not investigated. The pressure data at 123°C and 0.5 N NaOH were used to determine pressure dependency and the subsequent model proposed was taken as correct on the basis of the three points presented in Fig. 5 of the paper. In developing the

Jan 1, 1954

By James L. Hendrix, Pat Vreeland, Hamilton Vreeland, Marcel F. DeGuire, Peter L. Comanor

A study of the ground area surrounding the Getchell, Nev., gold mine mill tailings was conducted so that a better understanding of the effects of arsenic toxicity on Upper Sonoran vegetation could be obtained. The Getchell area was selected because of the known high values of arsenic currently contained in the tailings waste (1% or higher). Mill wastes as well as the scrubber product As2O3 are contained in the tailings pond. In order to determine the effect of the tailings disposal on the surrounding vegetation, plots and line-transect techniques were employed to obtain plant ecological information on the area surrounding the ponds, and also non-affected control plots. Data for percent ground cover, species frequency, and plant vitality as a function of distance from the tailings ponds were collected. In an attempt to isolate naturally occurring factors for varying plant communities from induced factors derived from the close proximity of the tailings, soil cores were

Jan 1, 1975

By E. H. Rutter, J. Hadizadeh

The development of microcracking with progressive strain through failure in an orthoquartzite has been studied by means of optical and electron microscopy of specimens deformed experimentally at 200 MPa confining pressure, 20°C. Microcrack maps and statistics have been prepared. The rock fails through the development of arrays of microcracks which form around grain boundaries and are initiated at notches on pore spaces. No special microstructural characteristic appears to be associated with the peak strength, and axially oriented cracks do not begin to develop until well past the strength peak. Axial microcracking is a precursor to shear fault localization. Because most cracks form in highly shear stressed orientations, it is inferred that most of the work done in rupturing the rock is against the frictional forces on crack surfaces. An attempt is made to integrate the work done in this way, to compare it with the work done by the external forces.

Jan 1, 1982

By Frank C. Schader

JOHN CARTER ANDERSON, Kingman, Ariz. (communication to the Secretary *).-From an extended study of the Oatman and Secret Pass districts of Mohave County, Arizona, I believe that the genesis of the ore deposits, in most cases, is directly connected with rhyolitic intrusions later than the Tertiary flows; and that the developments of, the future will prove these intrusives to be the primary source of the ore. In support of this opinion I will instance the Wilhelm-Eclipse dike in Secret Pass and the Murdock, Nellie, Black Range dike and ledge in the southern part of the Oatman district. The Wilhelm-Eclipse dike is a very fine-grained light-colored siliceous rhyolite dike with a strike of N.45W. traversing the full length of the Secret Pass district about midway between two major faults which mark the easterly and westerly boundaries of the district. These faults .have lifted the block between so that erosion has exposed the pre-Cam-

Jan 4, 1917

By Nick Turner, E Walker, George C. Bowser

A fully field tested mine-wide data/communications system is presented which integrates total data acquisition, control, and instrumentation into a single system. Installations at Kitt #1 and Amonate Mines (W.Va.1 use an LSI-11 series computer which communicates with easily installed field data stations over a single twisted wire pair. Complete field test data are presented, identifying the problems and successes experienced in the development, installation, operation and maintenance of the system, and the training of mine personnel. Of particular interest is the system installed at Kitt #1 which has been in continuous use since February 1982. The paper will also deal with the application of a computer-based carbon monoxide monitoring system installed at the Amanate mine in September 1982. The purpose of that system is to monitor air quality and to provide early fire detection in the belt entry to permit the use of belt air for face ventilation.

Jan 1, 1983