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By Bruno Deves Flores

O presente trabalho tem como objetivo investigar a influência da adição de carvão vegetal e do seu tamanho de partícula na reatividade do coque. Para isso, um carvão vegetal de eucalipto foi adicionado a um carvão médio volátil americano em três teores (3%, 5% e 8%) e em duas faixas granulométricas distintas (abaixo de 1 mm e entre 3 mm e 4 mm). O carvão individual e as misturas de carvão/carvão vegetal foram carbonizados em um forno de escala laboratorial (1 kg). A reatividade dos coques produzidos e do coque de referência foi avaliada e comparada usando análise termogravimétrica. Também foram realizadas análises morfológicas através de microscópio óptico e eletrônico, usando amostras antes e após os ensaios termogravimétricos. Baseado nos resultados, a influência da introdução de carvão vegetal na reatividade do coque foi analisada e discutida neste trabalho.

Aug 1, 2018

By Robert W. Waytulonis

Mining regulations pertaining to the use of diesel engines were solicited from foreign countries with mining operations by the Bureau of Mines. Responses were received from 27 countries; the information received and U.S. regulations were reviewed, and those parts pertaining to the use of diesel engines in underground mining were synopsized according to the following subject categories: types of engines permitted, testing and certification procedures, fuel quality specifications, emission control requirements, procedures and frequency of testing exhaust gases, mine air quality and quantity (ventilation) requirements, procedures for testing mine air quality and quantity, and noise standards. All categories except the types of engines permitted and testing and certification procedures are summarized in tables. Contacts are provided for each country to facilitate inquiries concerning regulation revisions or interpretation.

Jan 1, 1987

By Arne M. Myrvang

Rock stress measurements have been carried out by the Mining Department, the Norw. Institute of Technology (NTH) since 1964. Before that time rock stress measurements were carried out at a few locations by the Swedish professor Hast as early as 1958. From the very beginning the NTH engagement in the rock stress measuring field has been very practically aimed, and we have all the time enjoyed a very good cooperation with the Norwegian mining industry. At a very early stage the industry realized that proper measurements with proper equipment could be a very valuable practical tool. Hence the industry also was willing to grant considerable funds for the education of experts and development of measuring techniques. Since 1964 measurements have been carried out in the great majority of Norwegian mines. During the last years a large number of measurements have also been carried out in connection with hydro-electric power plants, road tunnels etc.

Jan 1, 1981

By G. R. Hopkins

According to reports received by the Bureau of Mines, Department of Commerce, as of January 1, 1929 there were 413 completed refineries in the United States, with a total daily crude-oil capacity of 3,509,540 barrels. In addition, 14 refineries, with a potential capacity of 99,000 barrels, were being constructed. Of the completed refineries, 341, with a capacity of 3,325,890 barrels, or 95 per cent of the total capacity, were in operation; and 72, with a capacity of 183,650 barrels, or 5 per cent of the total, were shut down. The improved condition of the refining industry in 1928 was indicated in several ways; namely, in an increase in the total capacity of the completed plants, in the opening up of a few plants which were shut down during 1927, in a decrease in the number of plants dismantled, and in an increase in the number of plants under construction. The majority of the refiners have followed a steady expansion program commensurate in most cases with the increase in demand for petroleum products. Obsolete equipment has been dismantled and modern equipment has been installed, with the net result that the total capacity of the completed refineries in the United States has shown a steady increase since January 1, 1918, the date of the first Bureau of Mines survey. Between January 1, 1928, and January 1, 1929, the number of completed plants fell from 423 to 413, but their total capacity increase 259,160 barrels, or 8 per cent. This compares with an increase in runs to stills of domestic and foreign crude petroleum of 10 per cent, and of domestic crude alone of 7 per cent.

Jan 1, 1929

More than 400 academic, government, and industry representatives attended the second symposium on ash utilization and technology held in Pittsburgh, Pa., March 10-11, 1970. Sponsored by the National Coal Association, Edison electric Institute, American Public Power Association, National Ash Association, and the Bureau of Mines, the symposium featured 23 formal presentations by leading experts from Europe and the United States on all major phases of ash production, utilization, and research. Abstracts of all the papers are grouped right after this introduction, and the full symposium proceedings follow. Biographical sketches of the representatives are given in an appendix. Sponsoring organizations and their chief representatives were the National Coal Association, James R. Garvey, Bituminous Coal Research, Inc.; Edison Electric Institute, C. E. Brackett, Southern Electric Generating Co.; American Public Power Association, Howard J. Stemm, Columbus (Ohio) Electricity Division; National Ash Association, Inc., John A. Tillinghast, American Electric Power Service Corp.; and the United States Department of the Interior, Bureau of Mines, William L. Crentz.

Jan 1, 1970

By H. S. COOLEY

TO talk about a "factor of economy" in connection with the wire ropes used in mining practice may be coining a new phrase. If such be the case it needs no other apology than that economy in wire rope usage is so bound up with the factor of safety as to justify a similarity in naming that makes one suggest the other. At the latest Wire Rope Research Conference, held under the auspices of the A. S. M. E., Re- search Committee and Engineering Foundation, data were introduced covering mine ropes working under

Jan 1, 1930

By F. D. Forgeron

"ONE OF THE FIRST DOCUMENTED APPLICATIONS of soil geochemistry in the Canadian Shield was that carried out by Chisholm in the Kenora district in 1949. This survey proved successful in outlining sulphide-associated gold veins utilizing cold-extractable metals. Since then, mining companies, government agencies - both provincial and federal - and universities have conducted soil investigations. Some of the results are documented in publications, others are on open file in provincial and federal mines departments and, unfortunately, many other investigations with both successful and unsuccessful results are buried in company files or have been discarded. This paper deals with soils within the scope of chemical studies of overburden in the Canadian Shield. The subject is a broad one and some definition is required. The soil investigations discussed herein are those aimed at the testing of specific targets more or less in the source area. This definition distinguishes soil investigations from other overburden studies which commonly monitor metal accumulations at some substantial distance from the metal source. Naturally this distinction is relative, because in many instances there is overlap."

Jan 1, 1971

By Paul Sarnoff

The economics of precious metals -- depending upon who is involved --could be the economics of hope, of fear, indeed of profit and perhaps survival. For those investors seeking capital gains in a puzzling economy, precious metals involve the economics of hope. Those who are convinced that currency soon won't be worth the paper it's printed on turn to precious metals because of the economics of fear. Gold and silver have been a storehouse of wealth since biblical times. The economics of fear during the past 500 years on the Continent has caused almost every European family to make sure a private stockpile or hoard of gold, silver or coins is at hand in case the paper currency of their country undergoes the kind of disaster that came to the German Mark after World War I. Understandably, for mining companies involved in the production of precious metals, the elements of operations and management are directly concerned with the economics of profit -- and perhaps survival. To the American miner the price of precious metals in the marketplace is a matter of daily concern. After decades of selling silver to the US Government at 64.64 cents an ounce, producing silver mines suddenly became faced with prices breaking $5, $10 and $20 per ounce, and approaching $50 an ounce during the period 1978-1981. What should the miner expect one year in the future? Five years?

Jan 1, 1981

By K. H. J. Clarke

"ALTHOUGH nickel was not identified as a separate element until a Swedish scientist, Axel Frederick Cronstedt, did so in 17 51, its utilization dates from pre-historic times. From its humble beginnings nickel has grown in importance until, today, in our clocks, television sets, automobiles, and air-planes, in our bridges, tableware, farm implements, and the equipment which processes our food, it is constantly at our service.For convenience in assembly, data and information relative to The Marketing of Nickel will be outlined in five phases: (A) Sources, (B) Distribution, (C) Utilization, (D) Market Development, and (E) Conclusions."

Jan 1, 1960

By Roger C. Malan

The Monument Valley and White Canyon districts are in northeastern Arizona and southeastern Utah. Exploration and mining for uranium has been conducted in these districts since the late 1940's. In July 1965, ore reserves plus ore production at 174 properties were approximately 3.3 million tons of ore containing about 19 million pounds U3O8, of which about 10 per cent remained in reserves. The two largest mines, Monument No. 2 and Happy Jack, together account for about 45 per cent of the sum of production and reserves. Approximately half the deposits in these districts contain less than 1000 tons of ore. Nearly 5000 feet of Permian, Triassic, and Jurassic sedimentary rocks, mainly continental in origin, are exposed in these districts. All the important uranium deposits are in the Shinarump, the basal member of the Chinle Formation of Triassic age. The Shinarump lies on a widespread unconformity. It is composed of fluvial sediments, generally less than 100 feet thick, that were deposited by streams flowing from a source to the south. Most of the deposits are in an arcuate belt, convex to the west. This belt, 3 to 12 miles wide, extends from Monument Valley northward nearly 130 miles. It is along the western flank of the ancient Monument Valley-Monticello upland, an area that was slightly uplifted at the beginning and again at the end of deposition of the Shinarump. Erosion and subsequent reworking of the Shinarump sediments in the vicinity of this upland are postulated to have made possible the transportation, in solution, of the uranium contained in these sediments. The soluble uranium probably was carried by migrating ground water into sites favorable for precipitation in Shinarump beds bordering the upland. Thus, the original very small amounts of dispersed uranium in the early Shinarump sediments were accreted in the favorable belt where the accumulations of carbonaceous plant remains and their decay products provided a persistent reducing environment.

Jan 1, 1968

By Primak. George J.

"In the development of a new product as well as during its introduction on the market, it is very important to give due consideration to problems involving patents, licenses and trade marks. At the very beginning of the research and development program, it is obviously essential to ascertain, through a suitable patent search, that the product in question will not infringe any patents which are still in force. Then, a possibility of achieving one's own patent or proprietary position on the product or the process of its manufacture should be carefully explored. Licensing arrangements that one may reach with respect to patents and know-how covering such new product may, in the final analysis, determine its over-all success or failure. If one can count on licensing revenues or some favourable cross-licensing arrangements with respect to a newly developed product, this may go a long way to achieving profitability and success. The selection of a good trade mark is probably one of the most important acts that one has to perform once the product is developed, as customers will identify the new product by such a trade mark. In many instances, successful marketing and widespread acceptance of a product are largely due to its appealing name or trade mark, accompanied by proper promotion and advertising. Once the trade mark has been adopted, it should be registered in the Trade Marks Office to provide the protection afforded by federal statute. If the product is to be manufactured, sold or licensed in some other countries, similar considerations should be made with regard to each such country."

Jan 1, 1973

The accompanying supply/demand flow diagrams and 10-year tables for mineral and fuel commodities present essential data required by government, industry, and others to formulate policies and programs that can help assure an adequate and continuing supply of mineral raw materials. The 10-year data base terminates with 1975 figures because adequate world information was not available beyond that date. The selected mineral supply/demand tables and flow diagrams comprise but one "output" from the massive body of information and data collected and compiled by the Bureau of Mines on a continuing basis covering mineral production, consumption, prices, shipments, imports, exports, and stocks, as well as industry activities in all States and abroad.

Jan 1, 2012

Law of the Sea. - The Ninth Session of the Law of the Sea Conference resumed July 28 at Geneva and will run for 5 weeks. The 160-nation Conference began in 1973. Two of the major factors to be discussed are the transfer of technology to the UN-controlled Enterprise or mining authority, and how the 36-member Council will make decisions. As the session completed its third week, delegates expressed little hope of completing a treaty text this year. There was a feeling, though, that substantive issues might be settled so that a treaty text can be completed next year. The Deep Seabed Hard Mineral Resources Act signed by the President on June 28, provides an interim regulatory procedure for ocean mining activities conducted by U.S. nationals that may be superseded by a law of the sea treaty.

Jan 1, 1980

By James T. McCartney, Joseph D. Davis

For more than 10 years coke-oven technologists have been investigating the expanding properties of coal on a scale larger than that afforded by laboratory test tubes. Koppers 4/ was among the first to realize that coals can not be differentiated satisfactorily with respect to expansion in coke ovens by the simpler test-tube methods; in his first method 80 grains of fine coal were coked in a cylinder heated from the bottom, so that the zone of fusion (plastic layer) advanced from the bottom to the top. The scale of test was too small; it has been modified by other investigators, but without significant improvement in practical application of the results. Somewhat later Koppers and Jendne 5/ experimented with a small-scale coke even, one wall of which was movable, in which the layer-coking in a coke oven could be simulated closely. This oven was heated from both sides. Their results with this oven showed a peak in the time-pressure curves near the end of the coking, period when the two plastic layers, advancing from opposite walls, meet. They also found that although the smaller oven was heated from one side only and did not show the Pressure peak characteristic of two-sided heating, it still gave results entirely too high. Russell built an oven similar to the movable-wall oven of Koppers and Jenkner and compared results obtained in it on Beckley expanding coal with these obtained on the some coal in the Altieri 7/ small-scale apparatus. Both tests were conducted at the same constant pressure, but heating was from two sides in Russell's oven and from one side in the Altieri tester. Russell found that the two types of test gave comparable results under constant pressure conditions even though the heating procedures were quite different. He showed later, however, that a "borderline" coal 8/ that contracted in the Altieri tester at constant pressure developed a peak pressure of 4 pounds per square inch in the movable-wall oven heated from both sides at constant volume. He concluded from this that testing at constant volume gave results more accurately indicative of dangerous expansion tendencies than those at constant pressure. He also found that heating from both sides in this oven gave higher pressure than heating from one side only.

May 1, 1942

THOSE who dabble in mining are no exception to the general rule that persons who know a little of a subject are apt to think that they know all about it. Some colour may be lent to the belief that anyone may succeed in mining when we hear stories ofsuccessful diggers and others who have accidentally dropped on to something good through no foresight on their part; but we seldom hear the contra account of the far larger number who fail. Those who go more thoroughly into the subject, and take up mining as a profession, know very well that it is not one that can be carried out successfully by rule of thumb, but when they point this out to the public they are credited with trying to make it a closed profession; and outsiders are for ever trying to find out the "trade secrets," at the same time spurning the main one, which is hard study, experience, and the ability to apply their knowledge. The average mining man is not rich. When he amasses a fortune it is generally through speculation rather than professional work, thought no doubt his technical knowledge may have assisted...

Jan 1, 1910

By Vaughan R. Voller

"The wide range of length and time scales found in solidification processes are outlined and discussed. Methods for Direct Microstructure Simulation (DMS) are introduced. Key features in sharp interface and phase field models are presented. Concepts in micro-macro solidification modeling are covered. Basic details of microstructure and segregation models are provided. A description of a recent segregation micro-macro model is presented in detail.IntroductionA solidification process involves the containment of a liquid region, which, due to cooling, transforms over time to form a fully solid product. The development of the solid microstructure and the segregation of solute components during this transformation are controlled by phenomena that occur across a wide range of length and time scales. A ""successful"" model of a given solidification process needs to account for these phenomena. Standard models of solidification employ a discrete grid of node points and associated volume elements in the special domain, with a discrete time step to track the transient changes of nodal values, describing the composition and microstructure. Through the use of such models significant progress has been made towards a complete understanding of solidification process and phenomena (see the conference proceedings in Refs [1-9]). As solidification models become more sophisticated, however, they all run into the problem of resolving the full range of disparate space and time scales.Two approaches can deal with this problem1. Direct Microstructure Simulation (DMS) where the grid size and time step are chosen to scale with the smallest length and time scales of the given problem.2. Micro-macro modeling where the grid size and time step scale with the macroscopic process scale and phenomena at smaller scales are accounted for via sub-grid modeling and volume averaging.Currently full DMS of solidification is beyond the reach of available computer power and the application and development of micro-macro models is an important and critical research area."

Jan 1, 2001

By Corwin L. Cooper

This vapor, which describes mining and milling methods and costs at the Knob Hill gold mine, is one of a series being prepared by the Bureau of Mines on gold mining and milling practices in the United States. The mining properties owned or controlled by Knob Hill Mines, Inc., are situated in the Eureka mining district on a country road 2 miles up Eureka Gulch from the town of Republic, county seat of Ferry County, Wash. The district is about 140 miles northwest of Spokane by road and 35 miles south of the international boundary line. The altitude at the mine office is 2,700 feet.

Jan 1, 1940

By Percy W. Bidwell

THE statisticians had defeated Germany months before she invaded Poland. With batteries of adding machines they had proved that she was suffering from serious deficiencies in critical food- stuffs and in practically all of the raw materials necessary for the conduct of modern warfare. Their calculations showed that with respect to fats, oils, wool, cotton, hides, petroleum, iron, copper and other metals, the Reich was bound to be at a great disadvantage vis-a-vis the French and British as long as the latter could keep open the lines of sea communication. The conclusion seemed obvious-"Germany can't win." The more cautious of the commentators introduced qualifications as to the length of the war and the tightness of the British and French blockade. They also made a third qualification as to the character of the struggle- whether it was to be a war of attrition or a war of movement. But since the invasion of Norway in April, there is no longer any doubt on this score. It is a war of movement-a war in which fuel, lubricants, and metals are being consumed on a scale never before seen.

Jan 1, 1940

By D. A. Larson

The Bureau of Mines conducted basic experiments to study the process of crack propagation with a wedge indenter. The work was conducted under plane stress conditions in a hard, brittle limestone. The purpose of these experiments was to first gain an understanding of the basic crack propagation process under a sharp indenter, and second, to determine how the crack propagation process could be used to improve mechanical fragmentation systems. Three methods of rock fracture with the wedge indenter were investigated in this program. These were the confined indentation tests, the unconfined splitting tests, and the edge chipping tests. The confined indention tests represent worst case conditions for crack growth and formed the lower bound on fracture efficiency. The unconfined splitting tests represented best case conditions and fixed the upper bound of fracture efficiency. The edge chipping tests represented an idealized fragmentation process based exclusively upon the highly efficient fracture propagation process. Edge chipping achieved a specific energy of 25 in lb f/in3 compared to conventional drag cutters, which required a specific energy of at least 2,385 in·lb f/in3? Thus edge chipping is up to 100 times more efficient than conventional drag cutting. Because of these promising results, more work is planned with the fracture propagation process in three dimensions.

Jan 1, 1987

The Canadian concept for nuclear fuel waste disposal is being assessed by AECL Research in a series of experiments at its Underground Research Laboratory (URL) near Lac du Bonnet. Manitoba, Canada. As pan of this research, the Mine-by Experiment has been designed to obtain information on rock mass behavior, the development of an excavation-induced damage zone and failure mechanisms around a circular bored tunnel. An iterative design approach was used to effectively reconcile the experiment objectives and construction logistics. This paper discusses the design considerations and construction methodology adopted on the project.

Jan 1, 1991