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By Blake M. Loring, Robert A. Colton

MELTING procedures for most metals and alloys usually include some provision for the control of oxygen, since this element frequently has some undesirable effect on the properties of the metal or alloy concerned. In the melting of the various bronzes, this is especially true, since oxygen can be introduced into the melt in a number of ways, most of which are difficult to control. In making bronzes from virgin materials, oxygen is usually present in the commercial grades of copper used; electrolytic he refined copper ingots usually contain from 0.02 to 0.05 per cent oxygen. When ingot metal or scrap bronze is used in the charge, oxides are almost always present to some degree. Under certain melting conditions and in certain types of melting equipment the atmosphere over the metal may be highly oxidizing. This, of course, may be desirable in the melting practice used, but is certain to introduce appreciable amounts of oxygen into the melt, and that may not be entirely desirable. From the foundry viewpoint oxygen may have several harmful effects on bronzes. The formation of excessive amounts of oxides may produce drossy metal, which, in turn, means dirty castings and a potentially high rejection rate. It is claimed, too, that oxides in the metal may combine with hydrogen to form steam and thereby produce porosity in certain of the bronzes. The presence of certain refractory oxides, such as SnO2, may be undesirable from the viewpoint of making machining difficult, or as possible stress-raisers in the metal matrix. It is often said that excessive oxide present in the liquid metal makes the metal run sluggishly. Since it appears impractical to try to control the amount of oxygen introduced into the metal beyond taking the economical limit of precaution about charging dirty scrap, it would seem that control of the oxygen content of the liquid metal offers the most promising approach to this problem. This might be done by using slags, or covers, or by the use of some element or compound added to the melt to remove oxygen preferentially. Most aspects of this problem have been considered and considerable work has been done along these lines. A reconsideration of the problem is indicated, however, by the controversial nature of the evidence at hand, especially on the possibility of using a chemical deoxidizer to control the oxygen content of bronzes. CHOICE OF DEOXIDIZER The choice of the chemical agent selected as a deoxidizer would naturally depend first on the alloy in which it is to be used; in this particular case the alloy is Navy gun metal. In Table I are listed a group of elements that might be considered as

Jan 1, 1946

By S. D. Dahlgren

ORDERED G.P. zones having the cesium chloride structure were found to exist in the bcc iron-rich grains of an Fe-Au-Cu alloy that had been supersaturated with approximately equal atomic percentages of gold and copper, and aged at 400° and 350°C. Streaks and superlattice spots in electron diffraction patterns revealed the presence of the ordered zones in the aged material. The ordered Ll2 structure is commonly found for precipitates in fcc metals (e.g., Ni3A1 in nickelL7') but it is uncommon to find precipitates in bcc metals having the cesium chloride structure. The formation of the G.P. zones caused age hardening of the grains. Samples containing 3.8 at. pct each of gold and copper (with the remainder being iron) were annealed at 95@ or 1125°C in quartz capsules and were quenched by breaking the capsules under water. X-ray diffraction patterns revealed two solid solutions in the quenched samples. One solid solution was bcc and the other was fcc. The microstructure consisted of iron-rich grains of 0.3 mm diam surrounded by a yellow gold-copper-rich grain boundary network. The Au-Cu phase diagram %hows continuous solid solubility of gold and copper with ordered phases forming below 410°C. None of the ordered Au-Cu phases have the cesium chloride structure. Both Fe-Au and Fe-Cu phase diagrams3 show extended miscibility gaps and only terminal solid-solution phases. Consequently, it is reasonably certain the iron-rich grains consisted of an a-phase terminal solid solution, and the grain boundary network consisted of a gold-copper-rich terminal solid solution. Lattice parameters of the quenched solid solutions were consistent with the suggestion that the quenched phases were terminal solutions. The lattice parameter of the bcc phase (2.879A) obtained upon quenching from 950°C was higher than that (2.866A) for pure iron. The fcc phase in this sample had a lower lattice parameter than that for a 50 at. pct Au and 50 at. pci Cu solid solution, i.e., 3.866 compared to 3.877A. The lattice parameter for the 50 pct Au and 50 pct Cu solid solution was interpolated from data for Cu-Au solid solutions.4 More gold and copper were soluble in iron at 1125°C than at 950°C as indicated by a 0.012A increase in the bcc lattice parameter for a sample quenched from 1125°C. After the alloy had been quenched from 950° and 1125°C, the bcc lattice parameters were 2.879 and 2.891A1 respectively G.P. zones having the cesium chloride structure-which formed during low-temperature aging—were detected by electron diffraction and observed with electron transmission microscopy. In Fig. 1, the asymmetrical streaks parallel to ( 100) directions indicate that platelike G.P. zones had formed parallel to (100) planes of the matrix. The direction of streak asymmetry shows that the bcc unit cell of the G.P. zones was larger than the bcc cell of the matrix. The ordered cesium chloride structure is indicated by low-intensity superlattice spots at 010 positions which are nonallowed for bcc structures. The superlattice spots are streaked; therefore they are from the G.P. zones and are not caused by rel-rod effects of a thin matrix phase. The appearance and size of the zones observed in electron transmission microscopy and the appearance of the asymmetrical streaks in the electron diffraction patterns for the Fe-Au-Cu alloy were the same as those observed for a similarly treated Fe-Au alloy.' Ordered G.P. zones were detected also for an Fe-Au-Cu sample aged only at 400°C. The production of the ordered cesium chloride structure zones by low-temperature aging of super-

Jan 1, 1968

By D. C. Sharpstone

THE Polaris-Taku mine is a new gold property, situated in the far north-west corner of British Columbia. Production was started in November, 1937, at the rate of 150 tons a day, and recently has been increased to 200 tons. The property, which promises to become one of British Columbia's important gold mines, was developed and brought into production in twenty-nine months after work was started on it as a virtual prospect in June, 1935, by Edward C. Congdon and associates. Inaccessibility, extraordinarily complicated geological problems, and difficult metallurgy retarded development of the property before acquisition by the present interests, an::l, in fact, discouraged two companies that had spent substantial sums upon it from continuing development. This paper is concerned with reviewing the development of the property and describing the principal features of the geology, the mining and metallurgical practices, and the equipment employed. Acknowledgments The writer is indebted to Mr. Edward C. Congdon, President of the Polaris-Taku Mining Company, and to various members of the mine staff for their assistance in assembling the data for this paper. Special thanks are due to Mr. George G. Griswold, Jr., of Butte, Montana, who generously and painstakingly prepared the section dealing with milling and power. Microscopic studies of ores were made by Professors Frank Grout an::l G. M. Schwartz, of the University of Minnesota, and by Mr. Griswold.

Jan 1, 1938

Institute of Metals Division Iron and Steel Division Extractive Metallurgy Division J C Kinnear, Jr, President A W Thornton, Past President W R Hibbard, Jr, Vice-President R W Shearman, Secretary-Treasurer AIME, 29 West 39th Street New York 18, N Y Board of Directors J B Austin, D L Clark, H B Emerick, T D Jones, H H Kellogg, C T Marshall, E E Schumacher, C S Smith, J D Sullivan

Jan 1, 1957

By James K. Richardson

Today, the enigma of the "missing man" in the metal mining industry equals, and frequently surpasses in objective importance, the problems of ore development, drilling, sampling, pumping, milling techniques, geophysical prospecting, or any one of a hundred highly technical subjects. Unfortunately, as engineers, we have confined our attentions, in the main, to the scientific phases of mineral technology, relegating our man power problems to the background. But what good has all our scientific study and preparation been if we can't get the ore mined, milled, or smelted? What has happened to our labor supply? Where is the good old miner who could timber, drill a round, lay track, or do any job underground?

Jan 1, 1949

By Peter Silveston, Earl Shannon

Process-oriented experiments on the use of coal as an adsorbent for certain soluble components of sewage are described. The capacity of Canadian coals for these components was less than 0.1 per cent by weight for the highest concentration at which these components could be expected to be found in domestic sewage. This is much less than values reported in the past. A pronounced selectivity between components was observed. Experiments on bacteria removal in beds of coal, regeneration of spent coal to restore adsorption capacity and COD contributions of coal are reported in the paper. The simple application of coal as an adsorbent does not seem promising.

Jan 1, 1970

By Lindsay D. Norman

Eleven major pyrometallurgical processes and operations suggested for recovering manganese from domestic resources are described. These include seven pyrometallurgical processes that usually yield a ferroalloy or a product from which ferromanganese can be produced in one operation. The remaining four involve pyrometallurgical operations whose products require either an additional two-stage process to produce ferromanganese or chemical processing to recover a high-quality manganese oxide product.

Jan 1, 1962

By John J. Sammarco

The U.S. Bureau of Mines is conducting research into computer-assisted mining, which requires investigation of new techniques for development and application of computer-based technologies. Today's technology can require significant effort in software development, as has become evident in the early stages of this Bureau research. Technologies for software automation, such as computer-aided software engineering (CASE), are available. This report explores CASE, its general features, and its importance in software development. Information is presented to assist in selection and application of the variety of CASE tools and methods for automating various stages of software development. When evaluating CASE for use, it is important to examine tools that support an organization's existing methods of software development. Support for existing hardware platforms must also be examined. Merely selecting a "good" CASE tool does not insure success. Thorough evaluation of implementing CASE is also critical. Subjects to evaluate for CASE implementation include organization culture, support from management and end users, training resources, and pilot projects. Organizations that benefit the most from CASE evaluate CASE features with respect to their needs and they properly implement CASE.

Jan 1, 1990

By Oliver Bowles

In 1943 the Bureau of Mines began a review of trends in consumption and prices of the more important nonmetallic minerals. The first report covering building materials4/ appeared in December of that year. The present paper, which deals with chemical raw materials and fertilizers, is the second of the series. The 34 years from 1910 to 1943, for which statistics are presented herein, comprise periods of uneventful peace, unparalleled prosperity, industrial depression almost to the point of stagnation, and two wars of world proportions.

Jan 1, 1945

By T. E. Evans, C. T. Baroch

ZrB2 was produced in batches of 4 to 6 Ib by interaction of ZrO2, B4C, B203, and carbon at around 2000°C in a simple graphite resistance furnace. Techniques of production are discussed and the final design of a suitable furnace is described in detail. Several other borides were made by the same technique and the process appears to have possibilities for commercial production. N seeking out new hard and refractory com- pounds, many researchers have turned to the investigation of the borides and excellent papers have been published on the properties of these compounds. Few papers, however, have appeared on the techniques and problems concerned with the production of these high temperature substances. This report describes progress made in developing a method for preparing zirconium diboride, ZrB2, on a pilot plant scale. The literature of the borides and other refractory hard metals recently has been reviewed, annotated, and classified so completely' that it is needless to attempt such an outline here. It is enough to say that three borides of zirconium have been reported: ZrB, ZrB2, and ZrB12.2 ZrB2 is the most stable of these and is especially stable in the presence of carbon up to and including its melting point of around 3000°C. Like most borides, it can be prepared in several ways. It can be prepared by synthesis of the elements, but these are expensive and difficult to produce in a high state of purity. Obviously, production directly from the oxides would have decided economic advantages. In electrolytic production such as that of calcium boride,:' the product is recovered as a sludge mixed with electrolyte; and separation of product from adhering electrolyte and regeneration of the electrolyte is an involved and difficult process. The work on borides was started on a small scale in 1948. Late in 1949, Naval Ordnance expressed a specific interest in ZrB2 and the project then centered on this compound. After the usual experimental work necessary in a new field, ZrB2 of good quality was produced by heating mixtures of B4C, ZrO2, B2O3, and carbon to a temperature of about 2000 °C in a resistance-type electric furnace. Over 100 lb was made for experimental use tests, and the method of production probably could be expanded into a commercial operation. A similar process has been described by Kieffer and coworkers.' The main chemical problems were the development of proper charges to insure complete reduction of the elements, determination of the proper temperature range at which these reductions took place, and adoption of techniques necessary to pre- vent inclusion of such impurities as carbon and nitrides. The mechanical problems consisted of developing a simple practical furnace that would attain the high temperatures required and permit use of a controlled atmosphere when necessary and determining of suitable refractories. Both problems were solved by designing a crucible resistance furnace. Crucible Resistance Electric Furnace Attempts were first made to produce ZrB2 in an electric arc furnace, but such a furnace would not provide the degree of carbon control required for producing clean graphite-free borides, so it was decided to try working in a crucible. Obviously, the furnace would have to be constructed of graphite, as the temperatures required are too high for other refractories or heating elements. Crucibles were made by hollowing out segments of graphite electrodes, which were fitted with a cover and clamped between two electrodes so that the current passing through the thin wall of the crucible would generate heat, using the principle of the Helberger crucible furnace."? Preliminary tests with this type of furnace were encouraging and led to the furnace design shown in Fig. 1. The essential components were a thin-walled graphite crucible resting on a graphite block, which formed the lower electrode assembly, and a top electrode assembly swung from a pipe column making contact with the top of the crucible. The space around the crucible was filled with graphite prepared from waste electrodes crushed to about ¼ in. This packing had excellent insulating properties, both electrically and thermally, and could be removed easily and quickly from around the crucible by means of an industrial vacuum cleaner. The largest resistor crucibles were machined from 8 in. electrode stock and were 26 in. long, with a side wall Yi in. thick and a 1 in. bottom. Temperatures were determined optically by sighting down a 1 in. hole drilled longitudinally through the top electrode and the crucible cover. Sealing this hole at the top was a water-cooled brass sight-glass assembly, shown in Fig. 2. An opening was provided for a light flow of helium to keep the sight opening clear of smoke, and a glass prism above the sight glass changed the line of sight to the horizontal for easier reading. More recently, the prism and optical pyrometer were replaced by a photoelectric recording pyrometer. At first the charges were placed directly in the resistor crucible but this meant that everything had to be withdrawn from the furnace every time the charge was emptied. Later, smaller crucibles were made up that could be placed inside the resistor

Jan 1, 1956

By S. Pastor, S. Hahn

"As the concept of autonomous haulage systems (AHS) moves from prototypes to production-ready applications, the operating performance of the haul road will become critical to the overall success of autonomy in mining. Deterioration in road performance will require remediation, human intervention and significant, albeit temporary, changes to operating procedures, to accommodate road maintenance. With autonomous trucks comes the opportunity to reduce road formation and operating width. This will, therefore, generate potentially significant reductions in stripping ratios and improvements to mine economics, but only if the design of the road, and its associated deterioration rate, is predictable and manageable, based on the materials used to construct the road and the maintenance interventions to be carried out on the road.This article presents the assessment of a digital photogrammetric approach to the characterization of a mine haul road surfacing, or wearing course material. Design and maintenance parameters for these roads are currently determined partly from physical particle size distribution (PSD) assessments of ‘in-road’ material. However, this approach does not accommodate the need, nor leverage the benefits from, AHS. The digital imaging approach is assessed in this article, using two standard digital analysis software tools, together with in-service mine haul road wearing course samples and images that are analyzed to determine the applicability and reliability of the approach to deliver a real-time assessment of haul road surfacing conditions and thus to identify the road maintenance interventions required to address deterioration.Enhancements in mine road design, construction and management for the past 20 or more years has largely been focused on short-term tactical needs. These improvements have not been matched by advances in the fundamental technologies that underpin mine road design and management and, although the quality of mine roads have probably"

Jan 1, 2015

By Alonso Marchena, William Martínez

El estudio que se ve reflejado en el presente artículo tuvo como objetivo mantener actualizado el mapa metalogenético del Perú y desarrollar conceptos sobre el origen de los yacimientos minerales, basados en datos geocronométricos, geoquímicos, isotópicos, estratigráficos y estructurales, en la Cordillera Occidental entre Ica y Tacna. La zona de investigación comprende las franjas metalogenéticas IV, V, VIII, IX y X. Se destaca el valor de herramientas tales como la litogeoquímica en la discriminación de pórfidos de Cu (Mo-Au) y se muestra la efectividad de nuevos parámetros de elementos traza en la discriminación y reconocimiento de magmatismo fértil vinculado a pórfidos en el sur del Perú.

Oct 30, 2020

By Dennis Keay, Barbara Schickner, P. L. Longenecker, Glenn J. Philips, Lee Rice, Herman E. Knight, Wayne E. Veneman, B. W. Washington, Robert S. Hess

The outlook for coal continued to improve in 1980, fueling expectations that a long-awaited boom is at hand. The surprising surge in coal exports contributed to the latest wave of optimism. Overseas exports hit 66 Mt in 1980, buoyed by a significant increase in demand for steam coal, up from 1979's 2.3 Mt to 15 Mt in 1980. US coal production rose 6.9% to 750 Mt in 1980 and total coal consumption increased 8.1% to about 725 Mt, due primarily to higher world oil prices and setbacks in the US nuclear power industry. Yet the industry is beset with problems-both internal and external. Although demand for US coal is growing, the industry's excess productive capacity is estimated at over 90 Mt/a. Public utilities, where real increases in coal consumption must come, are still moving slowly, blaming delays on antipollution equipment costs. Coal supplies are uncertain, subject to the vagaries of the UMW. For the sixth time since 1964, the coal industry and UMW failed to renew their labor contract without a national strike, reinforcing the perception held overseas that the US is not a reliable supplier. The expected boom in coal exports will, in part, depend on our ability to assure foreign buyers that US sources are dependable. The US industry is also plagued by inadequate facilities linking mines and consumers: inadequate rail systems, coal ports, and barges, For US producers to be competitive, ports must be expanded, rail lines improved, and harbors dredged to allow 136-kt ships to load coal. The im¬provements will require an enormous commitment and investment. Despite these major problems and unresolved issues, two factors continue to favor an increased reliance on coal as an energy source: abundant US reserves and coal's comparative price advantage. Coal's performance in the 1980s may at last exceed its promise.

Jan 5, 1981

By I. Ionel Gardescu

During the latter part of 1930 an agreement was reached among operators in Rumania to curtail the production of oil to about 100,000 bbl. per day. This agreement lasted only a few months and 1931 shows a new peak in production with an average yield of 136,900 bbl. per day as against an average of 116,600 bbl. per day for 1930. The total production for 1931 was 49,210,000 bbl.; an increase of 18.4 per cent over the previous year's production. It is interesting to compare the percentage production of the major companies to the potential production figures determined by the Government in September, 1930 (Table l), on the basis of which the proposed curtailment was to have been made. The three companies listed first in this table show an increase in average production for 1931 over their estimated potential production rating. This increase might be attributed at least in part to the recent development of the Boldesti field, which is controlled by these companies and of which the production at present is nearly 10 per cent of the total oil output for Rumania. Among the other fields, Moreni still holds first place with an output of 33.6 per cent, followed by Gura-Ocnitzei with 29.3 per cent. In both these fields the main source of oil is from the deeper Meotic sands. Other

Jan 1, 1932

By E. D. Fox

Introduction The financial statement of the hypothetical Gold Mining Company, which forms the background of this survey, was designed for the Institute with the express abject of having it assessed in respect to Profits by the several taxing bodies representing the Federal and Provincial Governments, which comprise the Dominion of Canada. On the completion of the figures, copies were sent to the several Ministers of Mines, accompanied by a request that they be submitted to their taxing authorities and assessed accordingly. The response, while it was not general, was very favourable, and at all times we were treated with the utmost courtesy and patience, and what has been set forth in the compilation bears the authentication of the various government officials who are immediately concerned with taxation. The data itself constitutes a fairly comprehensive digest of taxation as it directly applies to gold mining profits in Canada. The Hypothetical Balance-Sheet (See Exhibit A) In the balance-sheet schedules 1 and 2 (Exhibit A), income is divided between taxable and non-taxable classifications, and here it should be noted that the division contemplates only the assessment for Dominion income tax. The same applies to the factors of exchange and depletion. Therefore, in making comparisons, it is to be borne in mind that the set-up for assessment to the Provinces, that is, Manitoba and Alberta, will stand as if the gross non-operating income is taxable, with the reservations as shown in the notes below the schedules.

Jan 1, 1934

By G. E. McElroy

As one phase of a general program of enthracite mine-fire research initiated by the Bureau of Mines in September 1935, a study of the records of past fires was considered a necessary approach to a proper understanding of present and future fires because only limited information could be obtained directly from existing active fires on account of their inaccessibility. Through the courtesy of interested operators, all available records of fires that had occurred in a large group of steep-pitch anthracite mines in the Western Middle and Southern fields of the Pennsylvania anthracite district were examined and analyzed for data on the causes, costs, behavior, and control of fires, and this report is primarily a discussion of these factors based on a close study of these particular records. Mining Conditions The records pertain to a group of mines that have contributed about 12 percent of the total Pennsylvania anthracite production and constitute a large proportion of, and well represent, steep-pitch operations in this district. Throughout the area represented, the coal occurs as a series of up to 20 parallel seams in folded slate and sandstone strata and almost entirely on pitches of 400 to 80°, with vein thicknesses of 5 to 60 feet. Practically all are old mines with histories dating back to 1850, or thereabouts, and present operations are either under or adjacent to mined-out areas extending to surface or to the saddles of anticlines. All operations are at relatively shallow depths, that is, within 1,000 feet, vertically, of the surface. Mining methods are largely a heritage of the past and embrace typical breast and pillar operations with practically no mechanized mining and with the coal shot ?off the solid.? Most of the mines are rated as gassy and are operated now on a closed-light basis. Permissible explosives are now used entirely for breaking coal, and dynamites for rock work and chute-starting blasting.

Jan 1, 1938

By Alvin Kaufman

ANTHRACITE mining in the United States is concentrated in a 480 sq mile section of north- eastern Pennsylvania. The producing area is broken up into four fields, known as the Northern, Southern, Eastern Middle and Western Middle fields. These areas represent intricately folded coal measures in synclinal residuals left by erosional forces. Destruction by erosion has eliminated some 95 pct of the original coal. However, discounting the 5 billion tons removed to date, 8 billion tons are believed to be still recoverable.

Jan 3, 1953

By B. G. Russell

A wide range of minerals is found within the Republic of South Africa, many of which are exploited to a greater extent than in similar deposits found elsewhere. It is often asked whether this is atributed to the high grade of the ores encountered in this country, or whether such factors as fiscal and Infrastructural incentives create an economic climate that has en bled the mining industry to successfully extract and market minerals at a profit. This paper views South Africa's mineral resources in a regional and global context In an attempt to place the country's geological wealth in perspective. It represents the author's own Views, and not necessarily those of the Department of Mine al and Energy Affairs.

Jan 1, 1986

Outline of situations when valuations required - from capital raisings and takeovers, stamp duty, rates and capital gains tax, to probate and litigation between joint venture parties. Definition of types of exploration and mining properties as background to discussion on what methodologies to use (from grass roots to operating mine). Discussion on nature of alluvial deposits in New Zealand and how their characteristics and tonnage/grade uncertainties affect choice of methodology. Assessment of risk factors in New Zealand û technical, financial and socio-political (legislation, access, Maori land rights, environmental). Discussion of appropriate methodologies.

Jan 1, 1992

By F. V. Meriwether

The Bureau of Mines, in cooperation with the Federal, State, and local health services, and the mining companies, and miners? organizations, has for several years been carrying on sanitary surveys of mining districts in various states, with the purpose of collecting information on good and poor practices in mine sanitation, construction of approved wash-houses and change houses, the measures being taken to combat preventable diseases, the essential features of good houses for mining towns, and other conditions affecting the health and efficiency of miners and their families. The knowledge thus gained is disseminated for the common benefit of the mining industry. The sanitary conditions in the coal-mining districts of Alabama, as found by a recent survey made by the writer, are presented in this report. In addition to the towns on which this report is chiefly based, at least twice as many were visited where no details :were taken, but their general conditions are taken into consideration in summing conditions in the coal districts.

Jan 1, 1926