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Jan 1, 1892

By A. S. Richardson

VENTILATION of the Butte mines has long been a rather difficult problem because of the natural high temperature of the rock. With increase in mining depth, higher rock temperatures have been encountered, and this has caused a constantly growing demand for more effective ventilation measures. During recent years the hazards of dust in mine air have been more clearly recognized, and have necessitated the adoption of dust-prevention methods. To meet these ventilation problems in the mines of the Anaconda Copper Mining Co., a mines ventilation department was organized in 1918, to act under the direction of the general superintendent of mines. At the present time, under normal operating conditions, the force employed includes the ventilation engineer, two chief assistant ventilation engineers and eight assistant ventilation engineers. The activities of the department are, briefly: (1) planning and supervising operation of the general ventilation system; (2) planning and supervising the operation of dust-prevention measures, together with dust sampling and related microscopic work for the quantitation of the dust samples and determination of particle-size distribution; (3) the design and development of air- conditioning methods to meet present exceptionally severe temperature conditions and in anticipation of future requirements. To a large extent the technical features of the ventilation methods have been described in earlier papers by the author. This paper is written mainly to summarize past accomplishments bearing most closely on health and safety, with a somewhat more detailed account of the dust- prevention measures that have been developed comparatively recently. FACILITATING FLOW OF AIR As a basic requirement for the safety of the men, all ventilation plans are subject to a ruling that the main operating shafts must be maintained as inlet air courses. Under this condition, a safe, fresh-air escapeway is assured if a fire occurs within the mine, and the shaft is available as a base for fire-fighting operations. Control of the direction of air flow is

Jan 1, 1938

By Robert M. Jimeson

At the recent SME Fall Meeting in Salt Lake City, Robert M. Jimeson, Physical Science Administrator of the U.S. Bureau of Mines, cited the research programs underway in the Bureau's Division of Coal Research, and outlined their current status. These research programs have been selected by the Division because of their relative value and high probability of success in contributing to the conservation of the Nation's coal and to the expanded use of coal in current or new markets. Since about 50% of coal consumption in the United States is in the production of electric power, 20% in production of metallurgical coke, and over 20 % by industry in producing process steam and power, the Bureau has placed much emphasis on research that will maintain coal's leadership in these established areas. This emphasis is reflected in the projects discussed on these pages. Bear in mind that this survey is not all-inclusive. Other projects underway include studies on furnace performance factors, improved burner design, and other critical boiler work which can be used immediately by industry to improve efficiency of current practices in power generation; other investigations are aimed at reducing fireside deposits and corrosion of boiler and super- heater tubes, fly ash utilization, and control of SO, from flue gases (a major step in preventing air pollution). These plus many other projects during the past years have served to focus attention on the fact that the U. S. Bureau of Mines is presently making the largest single contribution to this Nation's coal research effort.

Jan 11, 1963

By Charles R. Simcoe

It was pointed out in a recent paper'g that the initial flow stress of as-quenched martensite is very low even in an alloy steel with an M, well above room temperature. It was also shown that the high ultimate tensile strength resulted from a very high rate of work

Jan 1, 1967

By Victor Phillips, J. P. Blair

Jan 1, 1952

By D. B. Grove

THE heavy media separation process plays an outstanding role in the concentration of 4000 tons of zinc ore per day at the Mascot mill of the American Zinc Co. of Tennessee. Of the total tonnage, 72 pct is treated in the heavy media separation plant to reject 56 pct of the ore as a coarse tailing, which has a ready market. Concentrates from this separation are beneficiated further by jigging and flotation. Approximately 25 pct of the total zinc concentrate production is made in the jig mill. Jig tailings are ground and pumped to the flotation circuit where the balance of the production is made. Fig. 1 shows a generalized flowsheet of the mill.

Jan 8, 1951

By C. C. Hatch, A. L. Mular

The methodology employed to develop a digital simulation of the Brenda Mines Ltd., Peachland, B. C., secondary crushing plant is described. Methodology includes data acquisition, data adjustment, model building, and the construction of a simulator structure. The simulator was utilized to study the effects of secondary and tertiary crusher close side settings, secondary screen opening, plant feed rate, and percent + 1 in. in the feed on the following responses: percent - 1/2 in. in the final product, plant reduction ratio, circulating load ratio, and screen efficiency. Results are presented in graphical form.

Jan 1, 1983

By Russell G. Haworth

Three companies, United States Potash Company, Potash Company of America, and International Minerals and Chemical Corporation, are now operating potash mines and refineries in the Carlsbad, New Mexico, area. The three mines are located approximately twenty miles east of Carlsbad. The deposits have been found ideal for mechanized mining methods. This summary has been compiled from information made available by the three operating companies.

Jan 1, 1949

By Charles White Merrill

Money is one of the most .pervasive elements in human life. The compensation for a workman's daily efforts is expressed as a wage and is measured in money. What an individual may consume depends largely on his income which also is expressed in terms of money. If he would start an enterprise its size would be determined in large part by the amount of money available for capitalization and its success would be measured in net income expressed in money. In short, the most widely used common denominator for comparing merchandise, real property, jobs, enterprises, gross national product, or personal success is money. Despite this use of money by almost everyone past infancy to express his appraisal of the in- numerable values he sees around himself, the complexity of the device called money makes its nature and workings a mystery to most users. Some of the difficulty in understanding money results from the fact that it has three distinct but interrelated functions: (1) a medium of exchange, (2) a unit of account, and (3) a store of value. In many statements about money the discussion moves from one function of money to another without the speaker or the listener recognizing the changes. For example, the housewife says "We took the money we had saved up to make the down payment and after twelve monthly payments the television will be ours." When this housewife spoke of "saving up the down payment" she referred to money in its function as a store of value; when she spoke of "the down payment" she was using money as a medium of exchange; and when she referred to the "monthly payments" she spoke of money as a unit of account. Another cause of confusion in understanding money is its paradoxical nature in that it represents both the power to produce and the power to consume. For example, when the rich uncle dies one nephew may regard his inheritance as an opportunity to buy a farm and leave the ranks of the wage earners to become an independent producer, whereas the other nephew may regard his portion as the means of living in complete leisure as a pure consumer.

Jan 1, 1959

By P. D. Southgate

VIBRATION, both ultrasonic and sonic, can affect the course of a variety of metallurgical processes. Reports of work on this subject have appeared at intervals over the last twenty years and a thorough review has been made by Hiedemann,' who gives a full list of references. It has been established that both refinement of structure and outgassing of the melt can be produced in most metals with sufficiently intense vibration. Many of the experiments in this field have been carried out using alloys of direct commercial interest in production- type casting equipment. Here a different approach is adopted, and simple binary alloys which exhibit different types of structure are used to facilitate examination of the effects produced under well-controlled conditions. Results from this kind of experiment should enable the basis of larger scale experiments with similar types of materials to be better substantiated. The alloys selected for this work are: 1) aluminum of 99.2 pct purity, the principal impurity being iron, near 0.4 pct; 2) A1-1.8 pct Fe, which is near eutectic composition; 3) A1-4 pct Fe—the second phase, of composition FeAl3, forms distinct acicular crystals; and 4) A1-12 pct Si—although this is of eutectic composition, the silicon normally appears in the form of large plates. Experimental Method There are three practicable methods by which acoustic vibration can be transferred to liquid metals: a) vibration of the whole of the container; b) electromagnetic induction; and c) insertion of a vibrating probe into the liquid. Method c is chosen here, and a frequency of 8 kc per sec is used. The end of the probe is electrically heated so that the metal near it will be the last to solidify. This ensures that vibration is transmitted directly to the liquid metal without passing through any solidifying and pasty intermediate region, which would attenuate acoustic waves severely. In addition, the heating prevents solid metal adhering to the probe, with consequent detuning. The transducer assembly is shown in Fig. 1. A stack of Permendur laminations 30 cm long acts as a half-wave vibrator and a winding along its length carries polarizing and energizing currents. It is joined by a half-wave coupling bar to a mild steel exponential horn, which tapers from 3.8 to 1.1 cm diam. A stainless steel stub 3 cm in length is welded on the free end. The assembly is supported by a plate located at the node of the coupling bar. Acoustic radiation losses are minimized by allowing the free end of the transducer to protrude above the surface of the cooling water. The exponential horn serves the function of matching the acoustic output impedance of the transducer to the radiation resistance of the probe into the melt. Electrical drive is provided by a 1 kw generator. Measurements of probe vibration amplitude during melt treatment are obtained from a gramophone pick-up with the needle attached to the wide end of the horn. This device is calibrated with a microscope before use. Liquid aluminum is very actively erosive and solution of materials with which the molten metal comes into contactcauses difficulties. Erosion of the probes in particular can be severe since it is greatly accelerated by the vibration. Tests of various acous-

Jan 1, 1958

By K. A. Natarajan, I. Iwasaki

Electrochemical measurements were made wing chalcopyrite and pyrrhotite electrodes in aqueous solution containing a xanthute collector and ground ore mineral particles. The purpose was to investigate the electrochemical reactivity of ozone with respect to dissolved xanthute, surface adsorbed xanthute, and the sulfide mineral itself. Electro-chemical evidence for the removal of xanthate coatings from chulcopyrite, pyrrhotite, and platinum surfaces by ozone is presented. The oxidizing power of ozone is compared with that of oxygen and other common oxidizing agents to portray the superiority of ozone as an oxidant.

Jan 1, 1986

By Kalanadh V. S. Sastry, D. W. Fuerstenau

Design and operation of a batch balling drum that can be used easily for experimental investigation of the balling or granulation behavior of particulate materials are described briefly. An experimental procedure for ascertaining the growth kinetics of iron ore concentrates or other particulate materials with this kind of apparatus is outlined.

Jan 1, 1972

Jan 1, 1936

By H. W. Fox, M. R. Achter

IN a previous study of the effect of atmosphere on creep-rupture properties,' it was shown that the relative strength of nickel in air and in vacuum may be reversed by a change in either stress or temperature, Fig. 1. At low stresses and high temperatures the metal is stronger in air but stronger in vacuum at high stresses and low temperatures. A mechanism to explain this reversal was proposed involving two competing processes; oxidation strengthens the metal while adsorption of gas lowers the surface energy, relative to that in vacuum, and reduces the work required to propagate a crack. The process which controls is determined by stress and temperature. In a number of private communications, however, the objection has been made that even in the vacuum of objection mm of Hg used in this study, the surface of a

Jan 1, 1960

By D. A. Kinneberg, J. W. Donaldson, N. J. Themelis

In the Kennecott Converter Smelting process (KCS), copper concentrate pellets are smelted and converted to high-grade matte in a modified Peirce-Smith converter using oxygen-enriched air and fuel. A high-grade matte bath is produced and maintained in the converter. Periodically, the slag layer is skimmed, slowly cooled, and its copper content is recovered by milling. Ladles of matte are transferred and finished to blister copper in another converter. The gases from the Kennecott Converter contain the SO2 products of the smelting and converting processes and can be treated in an acid plant, eliminating the problem of low-concentration gases associated with the operation of the reverberatory furnace. Pilot tests at Utah Copper Division were followed by a full-scale prototype converter test at the Chino Mines Division of Kennecott Copper Corporation. The concepts of the process and the results of this campaign are presented.

Jan 1, 1976

By Edward H. Robie

IN many ways, the Annual Meeting of the Institute in February was the most successful yet held. Attendance surpassed even that of the 75th Anniversary Meeting in 1947 with its international flavor. The number of technical sessions and the number and quality of papers presented almost certainly set a new record. The banquet was the best attended of any yet held even though the price reached a new high. Despite the demand for almost 1700 tickets to the banquet, some felt that the price-$13.50-was higher than they could afford. There are two points of view: One is that this is the big social event of the year for members and that it is worth from three to five dollars more to have it at the Waldorf and to have a luxury menu, as we did this year, with turtle soup, a fish course, guinea hen for the entree, and wild rice (which we understand is $3.50 per lb) for a vegetable. The other point of view is that a seven or eight dollar banquet of more simple food at the Commodore Hotel would more than make up in appeal, especially to the younger and less well-heeled members, what it would lack in glamour.

Jan 1, 1952

By Fred K. Stieler

The largest updraft sinter machine built has a roasting area of 132 sq.m. Sinter machines with an area of over 200 sq.m. are under consideration. These large machines require new techniques with regard to drive thrust and sealing mechanism. To optimize the results of sinter plants, the charge preparation systems and the return fines circuits were improved. Special crushers were developed for crushing return sinter of up to 800 ºC to a size of minus 6 mm. Strand cooling of Pb-sinter was investigated. Different methods for plant ventilation were compared. New processes, which might replace sintering in the future, are in the stage of large - scale testing.

Jan 1, 1977

Jan 1, 1936

By C. L. Berrien

Many fires have occurred in the mines of Butte in recent years, and while all have been of a serious nature, simply because they were mine fires, six of them have been especially dangerous in respect to loss of life and property, and the expense of extinguishing or controlling them. It is not my intention to discuss the relative merits of methods used in fighting these different fires because the conditions under which they occurred varied in each case, and it was not always advisable to expend the large sum of money necessary to actually extinguish them if they could be bulk-headed off from the rest of the mine. It is needless to say that everything possible has been done to check all fires at the beginning, but without success in some cases; and it has then become necessary to bulkhead all connections to them, in which state several now exist. The mine fires of Butte, or fires in any mine, may be divided into two classes, namely: Those occurring in accessible workings, and those occurring in inaccessible workings; because these two conditions govern to the greatest extent the methods of fighting fires. Accessibility and inaccessibility in the case of mine fires concern not only new open workings and old closed workings, respectively, but also the condition of the ventilation in and about those places. When a fire is accessible at the start it should not be difficult to confine it to a small area and extinguish it in a relatively short time, but when it is impossible to actually reach a fire in old filled, abandoned workings, or there is no opening by which the gases may be conducted away from the fire zone, then the time consumed in changing those conditions permits the fire to increase to such an extent that it is a long, hard fight to overcome it. These different conditions have been met in Butte, and of the six fires of serious proportions the Steward mine fire and the High Ore-Modoc mine fire were in new accessible workings and were extinguished in a month or so. The Anaconda mine fire, the Leonard-Minnie Healy mine fire, the West Colusa mine fire, and the Mountain View mine fire, were all inaccessible. The Anaconda mine fie started about 25 years ago and though safely bulkheaded is still active. The Leonard-Minnie Healy

Jan 1, 1916

By D. S. Choi, H. von Schonfeldt, H. D. Dahl

The design of pillars around a longwall panel in which the effect of the adjacent and worked-out panel is taken into consideration is discussed. A mathematical model is used to duplicate field observations such as opening closure and pillar rib movement. The model is then used to predict the effect of changes in mining geometry on the opening stability.

Jan 1, 1976