Search Documents

By W. E. Gaby

THE form of dip chart here presented for the use of the profession was devised by the author when he was confronted with a particularly heavy job of geological section making and. did not have any of the usual tables or charts at hand. This was at the property of the Teziutlan Copper Co. in Puebla, Mexico, where the orebodies are much faulted and lie conformably with a slightly inclined and. much folded schist. Because of the low dip and the folding of the orebodies, the engineering, and geological data respecting them were best represented on vertical cross-sections quite closely spaced. A less finished form of the chart was published in the Mining & Scientific Press of Aug. 6, 1921, with an explanation of its use. I have checked the new drawing for accuracy against the calculated table given, and constructed an explanatory diagram beneath. As some geologists are accustomed to using the table, I have included it, since no advantage is obtained by mere interpolations from the chart to get the required angle, except as it gives a mental picture of this angle. The chart gives a more rapid and much easier solution when cases multiply so that it becomes desirable to eliminate the tedious manipulations of a separate protractor. In fact, using the parallel ruler as des-cribed, it is not even necessary to make note of the angle sought. It is brought out graphically, leaving the mind free to note the correlations. The chart itself may be made more convenient by reproduction on celluloid with a slot running on the zero line of the protractor.

Jan 9, 1922

By S. S. Hartranft

FuRnace-men of the present day agree very nearly as to the best cooling-devices for the protection of blast-furnace hearths and boshes, and the best location of the cooling-system in the brick-work for the maintenance of favorable furnacelines throughout the blast. The replaceable bronze and copper plates are practically faultless; and there seems to be no reason why a furnace-hearth and bosh should not be held in good condition, by intelligent management and the use of replaceable plates, for a period several times the length of the average blast of to-day. While furnace-men have taken these .precautions to protect the hearth and bosh beyond the life of the lining, the portion of the lining above the mantle has been partly protected by some and wholly neglected by others. Some would not construct a furnace without mantle-plates, and others would not construct a furnace with them. In most cases, furnace-men have either trusted to Providence or to the bosh-plates for the continuance of favorable working-conditions above the mantle, and the prolongation of the life of the lining; consequently furnaces are constantly blown out for repairs to the lining, or for relining, when the hearth and bosh are in good enough condition to last through another blast. The following extract from one of Mr. James Gayley's con-

Jan 1, 1901

I HAVE already described to you many kinds of fusions and fires and still have many to describe if1 am to guide you, as I intend, among the operations of these processes. In all these, quantities of charcoal and various kinds of it must be handled continually and it therefore seems to me necessary to tell something about charcoal for aiding you in these processes. Without it artificers could scarcely bring their works to an end, because it is the food that nourishes the fire both for smelting and for softening the metals, or for calcining or drying things out. [61] It is a very powerful means and not only is its fire used for many more works than other fires, but it is also essential. Although there are many other things that make fire and would make it, I do not know of any that are better adapted for this purpose, or that can be more easily procured in large quantities, than wood and charcoal. For, as you can see, very great forests are found which make one think

Jan 1, 1942

By Chester Washburne

LEASING the Teapot dome to the Mammoth Oil Co. is the culminating anticlimax of the "conserva-tion movement." It is just the touch required to make a full fiasco of the whole affair. If the revered wielder of the "Big Stick" were still with us, we could hear it fall harder than it did on Ballinger. Of all the oil reserves set aside by presidential decree, there was only one which certainly could con-serve much oil for the future. This was Naval Reserve No. 3, on the Teapot dome, Wyoming. After secret negotiations, carefully guarded from the press and from the knowledge of other oil men, we are suddenly informed that this last and only known chance to save much oil for future naval needs has been given away for early development.

Jan 6, 1922

FRANK N. SPELLER,? Pittsburgh,. Pa.-Mr. -Hayward's paper again draws attention to the fact that copper in steel is not the enemy that a good many of us it one time thought it was. He shows clearly that steel with over 0.75 per cent. of copper is as dependable, under the :conditions which he describes, as the same steel without copper. I might add that you-can weld copper-steel- satisfactorily up to that point; in fact, we have succeeded in welding pipe by the lap weld process up to 1 per cent. copper. Notwithstanding the date that have been presented on the effects of copper on the physical properties and corrosion of steel, a maximum copper limitation is still found in many specifications. In some cases the limit is extremely low, such as below 0.05 .or 0.03: per cent., or thereabout. That is a relic of days gone by, and I think the practice should be discouraged. E. F. CONE, New York; N. Y.-Not so many years ago steel-casting makers were very particular as to the amount of copper that existed in the pig iron that they used. They would not use copper-bearing pig iron unless mixed with non-copper iron. I do not know what the practice now is in the particular foundry where I was metallurgist at one time,

Jan 4, 1918

Capital, as represented by mineral resources, is being exhausted rapidly without possibility of identical replacement. The public must be discouraged from thinking-why worry about the bank balance so long as there are plenty of blank checks? Instead of each man, woman, and child being owners of a mineral capital of $89,000 as former Secretary Ickes once stated, they are really the guardians of a mineral reserve which, when harvested, cannot be reproduced. The proper use of this material is the basis of modern civilization and military power. The best American institutions cannot be maintained or transmitted to our children unless this trust is guarded. It is unfortunate that more attention has not been focused on the fact that this country is headed for a have-not status in the family of great nations if some- thing is not done to preserve its mineral heritage. It is the privilege of the United States now to champion and implement democracy because it is industrialized and can get at its raw materials. A high price is being paid every day in mineral depletion for the privilege. No one can eat his cake and have it too. The United States still must face world-wide economic competition and, perhaps, World War III. In the final analysis all wealth comes from the ground, whether plant, animal, or mineral. Value is in-

Jan 1, 1950

J. Parke Channing, New York, N. Y. (communication tb the Secretary*):—Mr. Wright, in his introductory paragraph, says: "It is commonly believed by metallurgists that in copper-smelting, the copper in the slags, which is irreducible by continued smelting, is retained in the form of 'prills' of matte." On a recent visit to Greenwood, B. C., I was discussing with J. E. McAllister, the general manager of the British Columbia Copper Co., and the former metallurgist of the Tennessee Copper Go., this very question; and he held strongly to the idea that the copper in slag was in two forms—one portion contained in occluded matte and the other as an oxide. He believed that this same rule would apply to the silver in the slag. From my experience I am strongly inclined to agree with Mr. McAllister; and it appears quite reasonable that in furnaces treating oxidized copper-ores, and to a less degree in furnaces treating sulphide ores, there is always bound to be present a certain amount of copper oxide and silver oxide, which will behave like any base and get into the slag as such. We all know that in Arizona, in the early days, when it was customary to produce black copper, because the ores were nearly all oxidized or carbonates, and eulphur was scarce, the slags as a rule carried 2.5 per cent. of copper and seldom ran

Jan 1, 1911

By C. G. Dunn, J. L. Walter

COULOMB' and Coulomb and Lacombe2,3 have recently discussed secondary recrystallization in soft iron (99.5 pct Fe). They found that the appearance of this phenomenon was dependent on both the presence of impurities and the thickness of sheet specimens. They concluded that impurities such as carbon, sulfur, and oxygen in the soft iron stabilized the matrix structure and allowed growth of a few grains of specific orientations. They also found that secondary recrystallization ceased when the final thickness was small and attributed this complete inhibition of growth in thin sheet to the restraining action of thermal grooves. When purer iron (99.99 pct Fe) was used, normal grain growth but not secondary recrystallization was obtained. On the other hand it is known that the necessary stabilization of the matrix structure for secondary recrystallization in high-purity silicon iron probably does not depend on impurities but more likely results from the specimen thickness effect of Beck et al.,4 according to evidence and ideas advanced by Walter and Dunn,5,6 and Detert.7 Furthermore, Mullins8 has indicated that if a gas-metal surface energy difference exists across a grain boundary equal to or greater than about 3 pct of the grain boundary energy, then such a grain boundary should not become stuck. Similarly, Walter and Dunn have estimated that any increase in restraining force due to increased thermal grooving with decrease in

Jan 1, 1962

By Robert Greenwood

The advent of the space age and its promise of interplanetary flight has prompted new ideas for propulsion systems that will allow maximum energy with minimum fuel weight. The use of cesium as the source of energy for such rocket flights has been found desirable. Theoretical efficiency of a rocket fuel is measured in terms of specific impulse, defined as the number of pounds of thrust per pound of propellant consumed per second. Specific impulse is usually expressed in seconds (the number of seconds for which one pound of fuel would produce one pound of thrust) although it is really a measure of total energy, not of power. The most sophisticated chemical fuels have a specific impulse of 300 to 400 sec; liquid hydrogen heated by nuclear reactor has a specific impulse of 1000 to 1200 sec. Specific impulses as high as 20,000 sec, however, are theoretically attainable with the ion rocket, in which free cesium ions are accelerated across a voltage drop and ejected at high velocity.' Characteristics of the system have been sketched by Boden. The desirable properties of an ion propellant are: 1) low ionization potential, 2) low boiling point, and 3) high atomic weight. Alkali metals best fulfill these requirements, and Table I indicates the superiority of cesium. The use of heavy complex ions such as UCl; is ruled out by their instability and other disadvantages.

Jan 5, 1960

By W. R. Ingalls

THE MAJOR use of spelter has always been for the coating of iron and steel products, the process of coating being known as "galvanizing" and the products themselves as "galvanized," except for a couple of years during the war, when the consumption for brass making became superior, in the United States at least, owing to military demands. Since 1919, however, the consumption of spelter for galvanizing has regained the premier position, but not with such a long lead over brass making as previous to the war. The last development is ascribable to two main reasons, viz., an increased demand for brass in new industries, especially automobile manufacturing; and a diminished use of spelter per unit of iron and steel galvanized. MAJOR IMPORTANCE OF SUBJECT The last mentioned matter has already been the subject of some discussion and of some literature. The galvanizers have been charged with deliberately thinning their zinc coatings, with the consequence of producing inferior goods and thereby jeopardizing the whole galvanizing business. Zinc producers have been concerned about this, out of consideration of both the less use of zinc per unit of iron and steel and the fear that, the number of units produced may be curtailed. It has been argued, among other things, that the present policy of American galvanizers would impair their ability to compete in foreign markets with British galvanizers, who have been represented as making a superior product.

Jan 7, 1923

Jan 1, 1901

THE following employment items are made available to AIME members on a nonprofit basis by the Engineering Societies Personnel Service, Inc., operating in cooperation with the Four Founder Societies. Local offices of the Personnel Service are at 8 W. 40th St., New York 18; 100 Farnsworth Ave., Detroit; 57 Post St., Son Francisco; 84 E. Randolph St., Chicago 1. Applicants should address all mail to the proper key numbers in care of the New York office and include 6c in stamps for forwarding and returning application. The applicant agrees, if placed in a position by means of the Service, to pay the placement fee listed by the Service. AIME members may secure a weekly bulletin of positions available for $3.50 a quarter, $12 a year. MEN AVAILABLE Geologist-Petrographer. Experienced subsurface geology and petrographic rock and mineral identification. Desires position as either geologist or petrographer. M-682. Geologist, 36, married, employed. Nine years' experience geology connected with engineering, includes planning and supervising core drilling programs, study of stratigraphy and structure, special problems, report writing. Three years' teaching experience. Desires responsible position offering opportunity for advancement with progressive concern. Will travel part time. Available reasonable notice. M-683. Mining Executive with record of accomplishment organizing and directing efficient low cost mining and ore dressing operations available for position in the United States. Broad experience engineering, mechanized mining, flotation, safety, union labor relations and preparation of reports. Married. Employed; available upon reasonable notice. M-684.

Jan 1, 1952

By L. P. (Les) Haldane

Building a small underground coal mine is a risky endeavor, especially in the recent economic environment. ARCO's Mt. Gunnison No. 1 Mine, located in western Colorado, was designed and built as a small expandable speculation mine with initial production to be sold on the spot market, so it was very important to minimize capital exposure. This mine, operated by West Elk Coal Company, a subsidiary of Anaconda Minerals, was successfully built under budget at $35 million, and has been operating successfully since completion of construction in late 1982. The initial planning phase of a project is extremely important for testing the economic and technical feasibility of a proposal. The construction phase, by contrast, carries with it significant cost and quality risks which can relate to long-term economic and operating problems and therefore directly affect the viability of the project. This paper discusses several different aspects of the cost overrun risk involved in building an underground coal mine, and how attempts were made to minimize these risks during construction of the Mt. Gunnison Mine. Good people, construction planning, and execution are essential factors in assuring a quality, cost-effective project, with corresponding risk minimization during the construction phase and long term favorable implications for the operating phase.

Jan 1, 1985

By H. H. Clark

ELECTRICITY must be safeguarded everywhere that it is used. The conditions that exist underground make the use of safeguards more essential there than almost anywhere else. Electric Shock Electric shock is the greatest danger in connection with the use of electricity in mines, because conditions existing underground are so favorable to its occurrence. Men are often obliged to work in more or less uncertain light near bare wires that are carrying dangerous potentials. The fact that the men are standing on the earth practically connects them to one terminal of the electric generator. The most dangerous piece of electrical equipment underground is the trolley wire. It is necessarily bare and extends for long distances throughout a mine, often less than a man's height from the track rail. Sometimes the making up of trips of cars must be done near low-hanging trolley wires. All bare wires offer the same danger that trolley wires do, although not to the same extent. Apparatus that has accidentally come in contact with the ungrounded side of an electric circuit is almost as dangerous as the trolley wire. A severe and even fatal shock may be obtained by coming in contact with the frame of a motor or a switch box that has become charged with electricity, or "alive," as it is usually termed. It is also possible to obtain shocks from the frames of locomotives and cars if track. sanding, poor bonding or a similar cause has put a high resistance to earth in the path of the current.

Jan 4, 1914

By D. W. Rudd, D. W. Vose, J. B. Vetrano

In an earlier paper the permeability character of Mo-0.5 pct Ti to hydrogen was described.' It was shown that this alloy is a more effective barrier to the passage of hydrogen than previously studied systems, i.e., copper,2 nickel,3 and several stainless steels.4 The permeability of Hastelloy B to hydrogen was investigated as a material having promising high-temperature structural properties which might have a low permeability to hydrogen. The general theory of permeation has been previously discussed,' and here only a summary of the more important results are given. It is found that except for very thin membranes, at low temperature, permeation of a gas through a metal barrier is determined by the rate of diffusion of the gas through the crystal lattice of the specimen, and that for hydrogen and the common diatomic gases, this passage involves dissociated particles as the diffusing species. The rate of permeation for hydrogen is therefore proportional to the square root of the pressure. It has also been found that the rate of permeation is inversely proportional to the thickness of the barrier. The apparatus used in this investigation was fundamentally the same as that employed in previous studies,' except that several simplifications result in the case of Hastelloy, since oxidation at the temperatures investigated is no longer a problem and welding of the specimen is relatively easy. A cross section of the membrane assembly is shown in Fig. 1. When finished, the assembly is about 5 in. long. The wall thickness is about 6 times the membrane thickness. The membrane (A) can be maintained at

Jan 1, 1963

GENERAL GEOLOGIC DESCRIPTION The Escalante silver deposit located in southwestern Utah is an epithermal vein system consisting of a hanging wall and footwall vein, straight along strike and dipping about 1.2 rad (70°). The veins consist of banded quartz and calcite fissure fillings between volcanic wall rock that are silicified for some distance outward from the vein. The walls of the veins are sharp and the silver values are irratically distributed through the various bands within the vein. Only very low grade values are to be found in the wall rock on either side. The portion of the veins above the water table have been somewhat leached, with some secondary enrichment below. The mineralogical zonation is variable due to a fluctuating water table through geologic time. SAMPLE MANAGEMENT AND COMPOSITE ASSAYS Sample data for the deposit was obtained from over 50 diamond drill holes, from channel samples cut at intervals across a drift, and from scattered surface trenches along the out- crop of the hanging wall vein. Fig. 13-1 is a surface plan map showing the vein outcrop and some diamond drill locations. Two cross sections through the vein are shown in Figs. 1 3-2 and 13-3. Nearly all of the diamond drill core of vein material was assayed in 0.3-m (I-ft) lengths, from which weighted composite assays were manually calculated for the horizontal thickness of the vein. The centers of the composited samples were plotted in north and east coordinates and by elevation, and locations and assay

Jan 1, 1980

By N. C. Gay, P. J. Van Der Veever

The Klerksdorp gold mining district, South Africa, experiences a relatively high level of seismicity with many seismic events of magnitude greater than 4. These large events appear to have foci close to fault planes, most of which displace the strata by several hundred metres over a wide area. To help understand the mechanism of these large mining- associated seismic events, in situ stress measurements were made at 4 sites using "CSIR doorstopper" strain relief techniques. The sites were chosen close to, or some distance from fault planes and other structures. The results show that at all 4 sites a relatively large horizontal stress is oriented approximately north- west. The magnitude of this stress ranges from 0,78-1,O of the vertical stress. A marked horizontal stress anisotropy, varying from 13-30 MPa is also present. The dominant structural features are large, north-east striking normal faults which extend across the entire length of the goldfield. Displacements across these faults vary from a few centimetres to several hundred metres. Bedding plane faults across which large displacements may occur are also common as are north and north-west striking dykes. The majority of the faults strike at approximately 90º to the maximum horizontal stress and at all sites a large compressive stress plunges in the direction of dip of the strata and fault planes. Thus a significant shear stress may act across suitably oriented planes causing them to be in a state of potentially unstable equilibrium. This abnormal stress situation would exist along the entire length of the fault

Jan 1, 1982

By Howard L. Hartman, Burke O. Trafton

There is a fruitful area of computer competence which has gone virtually unnoticed by the mining industry. This is in the solution of its numerous fluid-flow distribution problems, involving the circulation of air, water and other fluids in conduits through mines. Typical of these is the mine ventilation system, which circulates air through mine openings to the working faces. The networks of interconnected airways in large mines-often resembling a tortuous maze or labyrinth defying representation by schematic, let alone solution-must somehow be resolved and analyzed, if effective and safe control of the ventilation is to be maintained. These are admirably suited to programming for solution by high-speed electronic computer. Not only can direction of flow be determined but quantity and head loss as well. EARLIER EFFORTS AT NETWORK SOLUTION The only prior attempt to solve mine ventilation networks by digital computer methods was made by a Japanese investigator1 in 1958 whose work went unpublished. Unfortunately, he employed a method of network analysis little used in the United States and one which could accommodate a maximum of only 30 airways. While his analysis seems unnecessarily cumbersome and involved, it did suggest that a digital computer approach was feasible.

Jan 9, 1963

By J. S. Bowles

DISCUSSION, M. Cohen presiding J. W. Christian (The Inorganic Chemistry Laboratory, oxford, Englandl)—I was very interested in Dr. Bowles' results on the suppression of the transformation by solid films of alcohol or propane. The transformation in cobalt, which is also martensitic, can be explained by a mechanism involving the reflection of "half dislocations" down a series of atomic planes.* This reflection process is similar to that considered by Frank13 for plastic deformation on a single slip plane and, as he pointed out, reflection would be impossible if the metal were immersed in a liquid of higher density. It seems possible that solid films of alcohol have a similar effect on the lithium transformation. Reflection should also be possible at a grain boundary, though a higher kinetic energy of the dislocation, and hence a lower temperature would be required. As Dr. Bowles used coarse grained polycrystalline speci- mens, transformation on cooling should still have occurred in grains which did not form part of the outside (free surface) of the metal. This may account for the X-ray lines of the low temperature phase which were found. There is thus the interesting possibility that in a polycrystalline specimen a liquid, or in some cases a solid, film of material of or or higher density will lower M,, while in a single crystal it should suppress the transformation completely. In the case of cobalt it is necessary to find a dense liquid which will not react with the metal at the transformation temperature. The most promising liquid appears to be pure lead, but it is very difficult to devise a method of investigating whether or not this does suppress the transformation.

Jan 1, 1952

By Carle R. Hayward

The growing importance of metallography has caused a corresponding interest in the improvement of apparatus for preparing specimens of metals and alloys for microscopic examination. The purpose of this paper is to describe an electric heating-furnace, a grinding- and polishing-machine, and a device for mounting specimens, which are used in the metallographical work at the Massachusetts Institute of Technology. These three pieces of apparatus were designed and made in the laboratory of the Institute, and each possesses some original features which may be of interest. Electric Heating-Furnace. The accurate control of heat necessary for metallographic work is best obtained by the electric-resistance furnace. Uufortunately, however, even the platinum-wound furnaces cleteriorate with use and ultimately burn out, while the cheaper resistance-materials are often short-lived. Since the resistance-coil must be replaced from time to time, it is of advantage to be able to make this change with as little trouble as possible, and this is an important feature in the furnace shown in Fig. 1. A is a cylindrical galvanized-iron can, with two handles, B. A porcelain tube, C, passes through the central hole in the cover of the can and rests upon the asbestos disk, D; the bottom of the tube is held in place by the asbestos ring, 3. The space, F, around the tube is filled with powdered magnesia. G is an ordinary assay-crucible, with the cover inverted so as to present a smooth top for supporting a second porcelain tube, H. The latter is wound with " Excello " resistance-tape, 0.014

Jan 1, 1912