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By L. O. Howard

Much work has been done recently on the lead-antimony system' in connection with lead-rich alloys of commercial importance containing less than 20 per cent. antimony. Dean, Zickrick and Nix have called attention to the perpetuation in the literature of several erroneous data, such as a eutectic temperature of 228° C. at 12.5 per cent. antimony, instead of 247° at 13 per cent. The series is given as a classic example of a straight eutectiferous series in such late books as those of Heyn and Grossmann,2 Jeffries and Archer,3 Guillet and Portevin,4 Pulsifer,5 Rosenhain,6 and Liddell,7 as well as the somewhat earlier works of Hofman (1918), Wang (1909), and Williams (1920). The work of Dean has definitely shown a solid solution of antimony in lead at about 2.5 per cent. antimony. While lecturing to a class in general metallurgy at the University of Idaho, the writer had the students prepare a series of lead-antimony alloys for the purpose of illustrating methods of thermal analysis. Proper proportions of powdered antimony (sold as C.P.) and. test lead were mixed and melted in graphite crucibles under a reducing cover. Cooling

Jan 1, 1928

By M. D. Hassiaslis

THE nature of a collector-coated mineral surface has been the subject of some experimentation and much speculation. Various aspects of the problem have been isolated and studied; it is probable, however, that there exist aspects as yet unrecognized, which are needed for a complete description of the system. The recognized elements of the problem are: 1-The nature of the chemical units comprising the film and the nature of the forces holding these chemical units to the mineral surface; 2-The orientation of the chemical units at the surface; and 3-The disposition of the collector units at the mineral surface. This report touches upon all three aspects of the broad problem; it deals, however, with a new and heretofore unrecognized element-the mobility of the collector units in the two dimensions of the solid-liquid interface.

Jan 11, 1951

By D. O. Rausch

The economic relationship between steepening slopes and decreasing waste removal requirements ahead of ore mining is one of the most important factors in the design of open-pit mines. The steepness and stability of the pit slopes often spells the difference between ore and waste profit or loss in low cost open-pit operations. Unfortunately, the technology necessary for designing stable rock slopes is still in the early stages of development. Past and current pit-design methods have been, and still are, empirical, with rock slopes frequently made too steep or too shallow. As such, large expenditures are often made for correcting slopes after failures occur, or for unnecessarily removing more waste material than required.

Jan 6, 1965

SINCE you have asked me many times in particular how those mirrors are made that are commonly called spheres,* and even though I have told you at other times, I do not wish to omit writing of it here again in detail, so that you may have as complete information as I can give you, both in order to satisfy you fully and because it belongs among the subdivisions of the subject that I have proposed. Concerning this, I first tell you that it was an ancient discovery, and in those times as today was celebrated, and worthily so. For the effects these mirrors produce are miraculous things incomprehensible to me, and the more I think about it the more I am bedazzled with wonder, nor do I know how to explain by theory of perspective the causes demonstrated by their effects. Marvelous indeed is the beauty of their shining clearness, but much more so is the fact that (according to the shape that the craftsman has chosen to give them) they reflect back the shadow of the things

Jan 1, 1942

By P. E. Price, N. J. Grant

DURING the course of creep studies in iron-chromium-nickel alloys, it became necessary to establish the limits of the two-phase ferrite-austenite field at 1300°C. The shape of this region, predicted from the iron-chromium and chromium-nickel binary

Jan 1, 1960

By Frank S. Hurley

To comply with the California Mine Safety Orders pertaining to transportation of mine workers over mine railroads, the management of the New Idria mine in San Benito County, Calif., designed special man-cars. The new regulations, dated October 1958, make it mandatory for mine man-cars to be designed for carrying five or more men to and from the mine workings. At the New Idria mine, largest single producer of mercury in the U.S., each shift normally employs about 70 men. However, with the possibility of a future increase in the work force, seven man-cars were constructed with a total carrying capacity of 84 men. The general design of the mine man-cars was dictated by safety regulations plus the physical characteristics of the mine-low headroom, limited side clearance in haulageways, and track irregularities due to ground swells. The cars measure 10 ft long, 44 in. wide, and 50 in. high and were built at an average cost of $450 per car. All assembly work was done at the mine site.

Jan 7, 1960

On Feb. 16, 1948, the Board of Directors of NME authorized the publishing of "Technical Notes" in METALS TECHNOLOGY. The purpose is to provide prompt publication of very short items of the following general types: I. Results of short investigations which do not warrant a paper. 2. The conclusions of extensive investigations of insufficient general interest to justify a regular paper. 3. Conclusions arising in the course of an investigation, which, because of interest to others in the field, the author wishes to present prior to completion of the investigation. 4. Pertinent factual comment (not mere argument) on the subject matter of previous "Notes." Such Notes will be subject to the approval of the Auxiliary and AIME Publications Committees, but can be handled more promptly than regular papers because they need not be referred to readers. The recommended maxi- mum length is 500 words; notes in excess of 1,000 words will not be considered for this type of publication. A graph or photograph may be included as part of the note when particularly illustrative. As with regular papers, contributions to the new section should be submitted to the Secretary of the AIME. Please furnish two copies each complete with illustrations.

Jan 1, 1948

GRAHAM BRIGHT,* East Pittsburgh, Pa.-Bee-hive coke ovens are usually located at the mines, where the gases from the ovens are not strongly objectionable because the communities are not thickly built up. The byproduct oven will naturally he located near centers of industry, to which the coal can be brought from different directions and desirable mixtures can be made; where also the byproducts can be readily marketed, while the gas can be utilized for industrial and domestic purposes. Not much thought seems to have been given to the gases escaping from the byproduct coke oven, which are more or less objectionable in thickly populated sections. When the byproduct oven shall have been more widely installed, this question is likely to become serious, and it will be necessary to apply remedies. May I ask what has been done, or is going to be clone, in this direction? S. A. Moss, ? Lynn, Mass.-One cause of escaping gas is that the gas exhausters do not supply the proper suction. If a satisfactory regulating governor is applied and the correct kind of gas exhauster is used, the trouble will be eliminated. J. I. THOMPSON,? Pittsburgh, Pa.-The hoppers Co. has made a careful study of the question of smoke prevention. The smoke caused by the operation of the byproduct coke ovens is infinitely less than that caused by bee-hive ovens.

Jan 11, 1918

Electro-mechanical actuator, self-protected for mechanical and electrical overload, is developed by RACO. Tubular housing consists of squirrel cage motor with hollow rotor shaft and inner threads in the rotor. Features stroke distance of 2-72 in. and wide range of trust (20 lb-10 tons). (100) Agglomeration systems, offered by Ferro-Tech, incorporate pelletizing, briquetting and extrusion systems to agglomerate materials too fine to convey, load or feed to a process. Equipment includes disc and drum pelletizers, briquetter presses, compactors, extruders, pugmills and mixers, dryers, coolers, feeders and conveyors. (101)

Jan 9, 1973

By Immo H. Redeker

The Asheville Minerals Research Laboratory at North Carolina State University is engaged mainly in applied nonmetallic mineral processing research to assist the North Carolina mining industry. The laboratory helped to bring the flotation process to North Carolina feldspar. spodumene, mica and phosphate producers and it maintains a versatile batch and pilot plant. The conservation of mineral resources through improved processing methods has been the object of most of the laboratory's projects. Current laboratory work is sponsored by three feldspar companies, the State of North Carolina, and the U.S. Bureau of Mines. This work is aimed at reducing the amounts of feldspar tailings in the Spruce Pine area. Mineral dressing techniques are applied to these tails to reclaim salable mineral products such as feldspar, mica, quartz, and to make a more uniform material for possible ceramic and other applications.

Jan 1, 1970

By W. L. Austin

At the Steptoe metallurgical plant, where ore of the Nevada Consolidated Copper Co. is beneficiated, a small copper-leaching annex has been in operation treating flue dust from roasting-furnace dust chambers, together with a siliceous oxidized ore. This leaching plant was designed to obviate smelting low-grade siliceous flue dust, which interfered with the operation of the reverberatories by forming a blanket on the charge. The major portion of the copper content of the flue dust accumulating in the upper chambers of the roaster flue, and at the stack, is water soluble, and also contains much free sulphuric acid and soluble sulphates. It was found that sufficient acid could be obtained by mixing this material with water to provide a lixiviant for leaching the siliceous copper ore mentioned. This was the sole source of the lixiviant used in the operation to be described. An analysis of the flue dust showed it to be composed as follows : Per Cent. Copper.............................................. 3.00 siO2................................................. 23.41 Fe................................................... 4.08 CaO + MgO......................................... 2.72 Al203................................................ 0.07 Free H2S04........................................... 19.94 SO3 combined as sulphate.............................. 25.10 H2O combined with the sulphates....................... 10.67 0................................................... 2.50 Total................................... 97.49 Copper soluble in dilute H2SO4.......................... 2.56 The oxidized ore, locally known as carbonate, has the following composition:

Jan 1, 1915

By Atmaram H. Soni

A statistical study of machinability led the writer to examine existing data in regard to a thermal conductivity-mechanical properties relationship. Various functional relationships were proposed and the multiple correlation determined by statistical methods discussed in detail in the 1iterature.4 The relationship having the greatest engineering and statistical significance is discussed below. The data for cast and wrought aluminum alloys''2 have been compiled and analyzed separately. The results of these analyses are presented in Table I. The empirical equations for estimating the thermal conductivity (cal sec-' cm-I °C) are: for cast aluminum alloys K = 0.584 -0.00984/ -0.00263 Hb [1] and for wrought aluminum alloys K = 0.604 -0.00424l- 0.00170 Hb [2] where 1 and Hb are the percentage elongation and Brinell hardness number. Results of a similar analysis pertaining to stainless steel3 are also given in Table I. This empirical equation for estimating thermal conductivity (Btu per sq ft per hr per °F per in.) is K = 216.19- 1.716l - 0.0997 Hb [3] The relationship between electrical resistivity and mechanical properties was also examined for aluminum alloys using the same statistical method. These results are listed in Table II. While the situation of exact multiple correlation

Jan 1, 1965

By A. Patton

E. T. McCLEARY, Youngstown, Ohio (written discussion).-Perhaps there is no question before the steel manufacturers of America today that causes them more worry than that of maximum production, together with good quality, and Messrs. Patton and Speller have clearly shown in their excellent paper how this may be accomplished. Any operation that tends to uniformity is certainly conducive to good practice, and as the use of roll scale in the converter eliminates to a large extent the variations in temperature due to varying silicon content in the pig iron, it should certainly give a more uniform product. At the plant of The Youngstown Sheet & Tube Co. the use of roll scale was started in the year 1908. A great many tests have been con-

Jan 4, 1917

By J. B. Hiskey, G. Ramadorai

This paper presents the kinetics of leaching pure wulfenite (PbMoO,) with sodium sulfide solutions. Wulfenite dissolves in the presence of sulfide ion according to the following reaction: PbMoO , + S= PbS + MOO;. Synthetic galena is formed and molybdenum is released to solution as molybdate ion. The reaction follows the shrinking core model and the leaching mechanism involves mixed kinetics where both diffusion and chemical reaction are rate controlling. Molybdenum extraction is explained in terms of temperature, particle size, and sodium sulfide concentration.

Jan 1, 1977

By C. L. Dake

RESIDUAL deposits occur both as products of weathering and as products of hydrothermal decay. PRODUCTS OF WEATHERING That climatic conditions affect greatly both the rate and the results of weathering, is shown. in temperate, polar, arid, and tropical regions, each of which will be considered separately. Weathering under Temperate Climates The decomposition of any rock is accomplished by the removal of the more soluble bases, and a concentration of the relatively insoluble oxides of iron, aluminum, and silicon. By reason of its some-what greater solubility, silica is much more subject to removal than iron and alumina. The two important residual end products of weathering are sands and clays, the former consisting essentially of quartz, and the latter of kaolin and limonite.1

Jan 5, 1915

There is no simple answer to the question, "What is the meaning of life?" The expressions of life are so multiple that life has different meanings for different spheres of thought, such as art, science, or philosophy; and it conveys a different significance to different persons, according to their individual development and interests. Life is complex from a philosophical point of view. The meaning of life is superficially positive and unmistakable only when approached from a mechanistic view- point; namely, that of biology or biochemistry, since these deal with the physicochemical basis of life processes. However, such a purely mechanistic or biochemical approach to the significance of life and the interpretation of man's behavior on the basis of purely physical laws is certain to run into trouble. Similarly, a concentration of effort upon materialistic advances in world progress is extremely dangerous. The possible consequences of splitting the atom, development of guided missiles, and possible bacterial warfare are timely examples. Man becomes more self-reliant as he extends his scientific and technologic discoveries and learns how to shape natural conditions to his own desires. When man will be able to travel to other planets in atomically propelled space ships and destroy whole worlds by pushing a button, a possibility which now seems to be within the realm of the predictable future, he will need the strong-

Jan 1, 1950

By John Batchelder, David W. Blake, Ted. G. Theodore

The Copper Canyon CIL-Au-Ag deposits include two geologically distinct hypogene ore bodies developed primarily in late Paleozoic rocks adjacent to a 38-m.y.old potassic-altered granodiorite, whose emplacement seems to have been controlled largely by the Virgin fault, a north-striking normal fault. Widespread but subeconomic concentrations of sulfides as fracture and cavity fillings in skarn apparently preceded the final intrusion of the granodiorite. In the west ore body, metals reached ore-grade concentrations through the massive replacement of andradite by chalcopyrite, pyrrhotite, and pyrite mineral assemblages. The east ore body probably formed after the granodiorite reached its present level. Data suggest that fluids associated with potassic alteration here were most likely composed of magmatic water mixed with some meteoric water.

Jan 1, 1977

By A. Kenneth Schellinger

IF the ball mill is considered only from an energy standpoint, it can be thought of as a converter of kinetic energy into heat energy and surface energy. The law of the conservation of energy must apply to the ball mill as it does to any machine or process in nature. The heat energy output of the ball mill is apparent to any casual observer of the operating mill since the outflow pulp will be appreciably warmer than the inflow water and rock. The rock in the ball mill is crushed by shearing of its ionic bonding caused by some impact-induced stresses beyond the elastic limit. As the bonds holding the mineral crystal lattices together are ruptured, new surface area is created on each unit of which a definite number of unsaturated bonds exist. Such unsaturated energy of bonding may be termed the "surface energy," and is a potential energy figure. This created energy was withdrawn from the ball mill system and represents an absorption, or disappearance of heat. To reduce the size of the rock, surface area must be created and with it the at-

Jan 6, 1951

By G. W. P. Rengstorff, L. E. Olds

PREVIOUS research has shown that cast molyb-denum has good ductility at room temperature if the metal is sufficiently pure. In practice, however, it is very difficult to reduce the impurity content of molybdenum to a few parts per million—the maximum content of impurities allowable to obtain reasonable ductility in coarse-grained molybdenum. Also, subsequent fabrication may reintroduce enough impurity to damage ductility greatly, unless extreme precautions are taken to protect the metal during working. The major impurities which embrittle molybdenum are oxygen, nitrogen and, to a lesser degree, carbon. It is reasonable to assume that the harmful effects of such impurities might be neutralized by small amounts of alloying additions. The desired alloying elements would be those which might fonn stable metal oxides or nitrides that would not be harmful to ductility, or thosewhich might increase the tolerance of molybdenum for oxygen and nitro-

Jan 1, 1958

By H. Bernstein

WHILE the beryllium -copper (2 pct Be) alloy is nominally nonmagnetic, the presence of iron impurity causes variations in the magnetic proper- ties which, at times, attain excessive proportions. This investigation was carried out to establish the effect of small amounts of iron on the susceptibility of the material and to determine if the effect could be minimized. Beryllium-copper is an age-hardening alloy which

Jan 1, 1959