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By W. W. Adams

The accident-prevention record of the coal-mining industry in the United States was more favorable in 1936 than in 1935, both from the standpoint of the relative safety of the individual miner on the job and of the price in life and limb that the Nation paid for its year's supply of coal. The increase in relative safety of the individual miner was indicated by a lower death rate and a lower injury rate than in the preceding year per million man-hours of exposure to the hazards of mining; that is, per million hours of work performed by the employees. (See table 1.) A reduction in the price in life and limb that the Nation paid for a year's supply of coal was indicated by a smaller death rate and a smaller injury rate per million tons of coal produced. Thus the individual miner was a better insurance risk, as far as accidents were concerned, in 1936 than in 1935, and a ton of coal used in the homes and industries of the country represented less human suffering than in 1935. The two points of view are distinct, and both should be kept in mind when considering accidents and safety in coal mining or in other industries. More men were employed in 1936 than in 1935, and more workdays were available for the individual miner. Large gains were also made in the total number of man-shifts and man-hours worked in the industry as a whole. In number of tons of coal mined, 1936 showed large gains over 1935. Moreover, the average output of coal per man-hour worked was higher in 1936 than in 1935. All of these gains were made without lengthening the average number of hours of work per man per day.

Jan 1, 1939

By HOWARD RICHARDS

THE dollar was, selected as the unit of currency by the Congress of the United States of America on Apr. 2, 1792. This "Dollar" currency is so much more convenient than the older British currency that the Canadian Government, among others, has adopted it with corresponding success. Just as the dollar is the unit of United States currency, so the meter is the international unit for measuring length. The various weights and measures used in - the United States have since Apr. 5,. 1893, been based on the metric standards. These fundamental standards are kept by the International Bureau of Weights and Measures, which is supported by the United States, Great Britain and the, other leading countries. of the world. Copies are held-in Washington and other capitals. (2) As the dollar is divided into 100 cents, so the meter, which is 10 per cent. longer than the yard, is divided into 100 centimeters or cm. And as the cent is divided into 10 mills, so the centimeter is divided into 10 millimeters or mm. In measuring clothing and other articles which do not require great accuracy, the centimeter is most con¬venient, so that such work is done in terms of centi¬meters.. Instead of speaking of a 15;2-in. collar, a 40-centimeter or 40-cm. collar is referred to. Where accuracy is needed, as in mechanical drawing, machineshop work, etc., millimeters are employed. Thus 8 mm., is the convenient equivalent for 5/16 inch.

Jan 1, 1921

By Oliver Bowles

In 1940 the Bureau of Mines issued a report describing all the cement plants of Latin America, their design, capacity, and output, and the cement imports, exports, and requirements of the several countries. Since that time there has been such great activity in cement plant construction that a revision of the paper is highly desirable. The present compilation comprises the essential data in the previous report together with descriptions of all cement plants completed, under construction, or planned since that date and an overall picture of the supply and requirement situation of each country. Before World War I, Latin America was one of the world's largest export markets for cement. Its dependence on outside sources created no special problems of supply until the shortage of shipping and abnormally high prices of the First World War stimulated a movement toward greater self-sufficiency. Under this incentive many cement plants were constructed, and several countries were able by 1939 to manufacture enough cement for their modest needs. Substantial imports were still required for many important areas, and as the volume of demand was rapidly increasing the Latin American countries as a whole were far from self-sufficient in cement when tine Second. World War began. South and Central America depended to a large extent on European countries, chiefly Germany arid Belgium and to a smaller degree Scandinavia, United Kingdom, France, and Italy, to Supply their cement shortages. The cost of manufacture in these European countries was much lower than in the United States, and transportation expense had been kept at a particularly low level because of the two-way trade that had been developed. Ships destined for Latin American ports for coffee, tropical woods; fruits, and other native products could carry cargoes of cement on their westward voyages at very low cost In some instanced cement was taken in exchange for South American -products because cash was not available. Great Britain had withdrawn from this market to quite an extent because of low prices and because trade with its own Empire had been increasingly fostered. United States trade in cement with Latin America had been confined principally to white and other special varieties. In few places could ordinary portland cement made in the United States compete in price with the European products; although in general it was of better quality and cool d be delivered more promptly.

Jan 1, 1946

By Thornton L. Neathery

Vertical magnetic surveys have been made over about 3, 150 miles of the crystalline area of east-central Alabama. A contour map (100-gamma interval) showing regional magnetic anomalies has been prepared (scale 1:250,000) from data points located at quarter-mile intervals on all public roads. Small one- and two-station anomalies were eliminated, leaving only areally extensive anomaly features associated with regional geology. The regional gradient was "filtered" from the basic data and the resulting magnetic configuration compared to the regional geology. Regional lines of vertical magnetic intensity trend northeast and follow the structural framework of the area. Correlations can be made between a large number of geologic and magnetic features. The strongest regional anomalies are associated with the Goat Rock, Bartletts Ferry, Towaliga, and Brevard fault structures. The Inner Piedmont area is characterized by a broad regional high. The magnetic values of the northern Alabama Piedmont grades gently northwestward, disrupted occasionally by elongate highs and lows associated with amphibolites or granites. Scattered throughout the Piedmont are anomalous areas of high magnetic intensity; some are related to magnetic-bearing rocks, and some Indicate possible mineralization. Most of the anomalies have not been evaluated,

Jan 1, 1972

This: symposium was sponsored by the Bureau of Mines, U.S. Department of the lnterior, in order to critically examine the state-of-the-art of sulfide flotation chemistry and to define current and emerging problems that should be emphasized in future fundamental research. The topics covered through invited papers include both reviews and recent research results in the areas of thermodynamics of reagent-mineral interactions; collector adsorption processes; the effects of solid-state point defects on flotation; activation and deactivation phenomena; the electrochemical role of oxygen in sulfide flotation; environmental problems in flotation; and selective flocculation of fines. Papers riving perspectives on flotation research in relationship to our national mineral requirements and the relationships between industrial flotation research and academics are also presented. An edited summary of the symposium follows the papers.

Jan 1, 1980

By Hal J. Kelly

A number of problems that developed in processing the halloysitic clays of eastern Washington and northern Idaho were investigated by the Bureau of Mines. The deflocculating effect of tetra sodium pyrophosphate is compared with several other compounds, and on the basis of current theory, the advantage of sodium pyrophosphate as a deflocculating agent is explained. The adsorption of the sodium ion by clay in a clay"-water system was established by a radioactive tracer technique, and the deflocculating action of sodium pyro- phosphate was postulated. The effective dispersion of the halloysitic clays was limited by the occurrence of tightly bound aggregates of small, individual crystals. Disaggregation of the agglomerates was investigated by liquid extrusion and ball milling of dilute slurries and by extrusion of the clay in a plastic state. The greatest increase in the production of small particles was by high? pressure liquid extrusion.

Jan 1, 1963

By M. H. Attia

The concept of sustainable development has been evolved into a working framework for sustainable manufacturing, in which the environmental requirements are introduced into product development at the design stage. This keynote paper is discussing a number of issues pertaining to the impact of manufacturing on the environment. The conflicting requirements of sustainable development, sustainable manufacturing (SM) and economical growth are presented in the light of successful case studies that were able to convert conflicts into opportunities. Integration of SM into the product life cycle is also presented. A number of concepts that are related to Ecoefficiency, e.g., inverse manufacturing, demanufacturing and re-manufacturing are also discussed. The paper underlines the fact that the positive impact of this new philosophy is equally applicable and beneficial to both; developed and developing countries. The paper concludes with an overview of Global trends in environmentally benign manufacturing (EBM); e.g., product-take back and emerging material and processing technologies. The state-of-the-art approach to Life Cycle Impact Assessment and integration of design for the environment DfE principles are demonstrated through some case study.

Jan 1, 2006

By G. M. Bond

Reduction of the emissions of greenhouse gases, such as CO,, is currently the subject of extensive research. A novel strategy is put forward here, based on a biomimetic approach providing accelerated deposition into carbonate form for long-term sequestration. It offers the advantages of a process that: does not require concentration of CO, from flue gases; could potentially be used in an on-site scrubber to provide a plant-by-plant solution to reducing CO, emissions; is an environmentally benign procss with an environmentally benign product; and is based on readily available, low-cost reagents (except perhaps the catalyst).

Jan 1, 1999

By J. E. Dutrizac

"The end of an era in zinc metallurgy took place on July 31, 1976 when the horizontal retort furnaces of the National Zinc Company in Bartlesville, Oklahoma were permanently shut down (1) . For more than a century, horizontal retorting had been the most common method of producing zinc in the United States; it was a thriving industry in many parts of that country, especially in the natural gas belts of Oklahoma and Texas. With the Bartlesville closure, yet another metallurgical process has become an object of historical interest for North American metallurgists. Although shrouded in controversy, the origins of zinc metallurgy seem to date back at least 2000 years. Pyrometallurgical methods with carbon reductants are capable of producing zinc from oxidic zinc ores, but only above the boiling point of the metal. Although slow cooling results in re-oxidation of the zinc vapour by air or carbon monoxide, quenching yields liquid zinc; some form of rapid cooling, either accidental or intentional, was likely used by ancient metallurgists to liquify the metal. Zinc metal found in Athenian objects of the Roman era was likely of accidental origin. The Romans employed brass extensively for coins and ornaments(2) , and this was intentionally produced by the calamine process whereby oxidic zinc ores were added to molten copper under strongly reducing conditions. Zinc appears to have been known in China and India as early as 1000-1300 A.D., and was probably smelted commercially in those countries from the 14th century. Although the early metallurgical procedures were probably inefficient, they were able to produce zinc metal in significant amounts. The large heaps of zinc residues with clay retorts bear testimony to an early smelting industry of impressive magnitude. It is estimated that the heaps at Zawar, India alone represent the extraction of 100 000 tons of metallic zinc(2) In the 1730s the smelting of oxidic zinc ores was developed in England using a vertical retort method. In 1788 a British patent was granted for making zinc from zinc blends (ZnS) by roasting the ore in a coalfired reverberatory furnace, mixing the calcine with charcoal and smelting the mixture with suitable zinc condensation. The English process was very energy intensive, however, and early in the 19th century the Belgians developed a horizontal retort process for the reductiondistillation of zinc that was more fuel efficient. This technique was gradually developed into what came to be known as the Belgian process, the forerunner of the ""modern"" horizontal retort furnace."

Jan 1, 1999

By Jennifer A. Slatnick

Chlorofluorocarbons (CFC's), once universally accepted as ideal compounds for use in cooling and refrigeration, in foam production, and in cleaning electronic components, are being phased out and eventually banned under extensive international agreements because the chlorine in CFC's is thought to deplete the Earth's ozone layer. The industry has responded with the introduction of alternatives in the form of hydrofluorocarbons (HFC's), which contain no chlorine, and with hydrochlorofluorocarbons (HCFC's), which fill an intermediate gap in the replacement of CFC's. As a result of the elimination of chlorine in the HFC's and the reduction of it in the HCFC's, these alternatives contain more fluorine than the CFC's do. Other nonfluorocarbon substitutes, known as not-in-kind alternatives, contain no fluorine at all. As a result, the fluorspar mining industry, which is the source of fluorine in fluorocarbons through intermediate hydrofluoric acid, is being affected. Concern for this impact has led the U.S. Bureau of Mines to employ its capabilities to analyze various scenarios in the evolution of CFC replacements and substitutes to determine their effect on fluorspar mining. This report utilizes a network flow model to examine the effects of proposed replacements for CFC's, in terms of fluorine content, on fluorspar operations worldwide and on hydrofluoric acid plants in North America and Europe.

Jan 1, 1994

By C. M. Wright

Siendo la veta principal San Cristóbal, una de las estructuras que atraviesan el Anticlinal Chumpe en la provincia de Yauli, su explotación ha sido limitada a las rocas volcánicas y filitas en el flanco sur-oeste del anticlinal. Por tal motivo, el texto señala que el análisis de la distribución de los metales y minerales dentro de la veta, revela un zoneamiento horizontal bien definido, que es compatible con el origen de las soluciones hidrotermales en el centro del anticlinal. Asimismo, este estudio cuantitativo determina las características de las partes ricas de la veta, trazando líneas de contornos de los cuatro tipos de metal en secciones longitudinales, como los controles de la distribución de metal y relaciona las áreas ricas de la veta con su medio geológico. De otro lado, en San Cristóbal, la distribución del metal presenta una característica zonal donde la paragénesis y el zoneamiento están íntimamente relacionados. Concluyéndose que con la aplicación de los resultados de este estudio, se permitirá una mejor exploración y desarrollo de las áreas ricas de la Veta Principal San Cristóbal y se proporcionará una guía útil para la exploración y desarrollo de vetas paralelas en esta área.

Aug 20, 1963

By Bernard Lewis

During the past 10 years the technical investigations conducted by the Explosives Division of the Mine and Explosives Bureau of the Bureau of Mines have been described in a series of summarizing reports prepared by Wilbur I. Huff, consulting explosives chemist of the Bureau. These reports covered the…

Dec 1, 1947

By W. W. Adams

Every man-hour of work performed in and about the coal mines of the United States had a 2-percent heavier death load from accidents in 1938 than in 1937. This is an unorthodox way of stating that the death rate per million man-hours of exposure or employment was 2 percent higher in 1938 than in 1937, increasing from 1.74 to 1.78. Thus the average miner had a 2-percent greater chance of being killed in 1938 than he had in 1937. The average quantity of coal resulting from 1 man-hour of work increased 3.6 percent -from 0.615 ton in 1937 to 0.637 ton in 1938. The production of the average ton of coal was accompanied by a slightly smaller loss of life in 1938 than in 1937, the accident rate being 2.793 per million tons in 1938 compared with 2.833 in 1937.

Jan 1, 1941

By J. Keith Haddock

"Introduction The Luscar company, Forestburg Collieries Ltd., operates the Diplomat Mine located 14 km south of Forestburg, Alberta. Production is now at a declining rate from the 1 million tonnes achieved in 1978 as the reserves are being depleted. Three pits are operated at this prairie strip mine utilizing draglines and stripping shovels to uncover the coal. The coal is hauled to a tipple on site for shipment by rail or highway vehicles or is hauled directly to the adjacent Battle River Generating Station. Geology The mine is currently extracting the Battle River seam on the north side of the Battle River. This is the lower-most seam in the Horseshoe Canyon Formation and is the only one present in the area, the upper seams having been eroded by glaciation. The seam lies generally flat and varies from 2.0 to 5.0 metres thick. It lies under glacial till overburden varying in depth from 5.0 to 12.0 metres. The mineable coal extends from the side of the Battle River valley where it outcrops, to approximately 2.5 kilometres to the north. The mine is spread out over a distance of 8.0 kilometres in an east-west direction. Reserves and Coal Quality After over 30 years of mining at Diplomat, there are now less than 1 million tonnes of mineable reserves remaining on the property. With the commencement of coal production from the Paintearth Mine in 1981, supply to the Battle River Generating Station, formerly Diplomat's biggest customer, is being transferred to Paintearth. Rail shipments and domestic supply will continue until reserves are depleted. The coal has the following specifications:"

Jan 1, 1985

By R. C. FLEMING

MINING rock asphalt for use as a paving material is an industry which has grown with the spread of the good roads movement. "Mineral Industry During 1930" reports asphaltic pavements constructed, including maintenance and repair but excluding pavement constructed with road-oil, cut-back or emulsified asphalt, as grown from 23 million square yards in 1911 to a high of 144 million in 1927. In 1930 the same source reports 106 million square yards of such paving laid and, in that year, 664,871 tons of native rock asphalt were so utilized. Many states contain rock asphalt deposits of greater or less importance but in only a few places are the de¬posits being mined commercially. In the year cited Ken¬tucky produced 305,024 tons of bituminous sandstone, Texas 270,138 tons, mostly bituminous limestone, while Alabama, Oklahoma, California and Utah produced 89,709 tons of bituminous rock for road construction. In addition Utah produced 37,906 tons of the purer asphaltic products, gilsonite, wurtzilite and ozokerite, for other uses. Speaking generally, the rock asphalt is a sandstone or limestone naturally impregnated with asphalt to an extent that makes it an ideal road surfacing material without mixing or treatment other than crushing. The asphalt content of the commercial product runs 8 to 12 per cent.

Jan 1, 1933

1. Domestic Production and Use: In 1983, 12 companies operated 27 primary aluminum reduction plants, with 4 firms accounting for 65% of production. Washington, Oregon, and Montana accounted for 35% of the production; Indiana, Kentucky, Maryland, New York, Ohio, and West Virginia 35%; Tennessee, Alabama, South Carolina, and North Carolina 14%; other central States 16%. Based on published producer prices, output of primary metal in 1983 was valued at over $5.7 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Packaging accounted for an estimated 37% of domestic consumption in 1983, transportation 19%, building 17%, electrical 9%, consumer durables 8%, and other uses 10%.

Jan 1, 1984

By M. E. Steidlitz

FABRICATION of semiconductor devices.requires the formation of electrical contacts, often involving the use of lead, tin, and lead-tin solders. In several recent instances when germanium had been bonded to nickel with lead, a new metallic phase appeared, unattached to either germanium or nickel, but rather suspended as a continuous foil wholly contained within the lead matrix. Since such metallic structures do not form in nickel-lead or lead-germanium systems under identical conditions, a brief study was made of the characteristics and possible formation mechanisms of this material. EXPERIMENTAL Specimens were prepared by placing single crystal, transistor-grade germanium discs, 30-mils in diam by 6-mils thick, into a depression in a graphite boat. =A* nickel washers, 125 mils in diam by 5-mils thick, containing a center hole of 10-mils diam, and coined into a soup bowl shape, were loaded on top of the discs, so that the bottom of the

Jan 1, 1959

By W. F. Boericke

WORLD production of silver in 1929 totaled 256 million ounces. In 1928 production was 258 million ounces, and in 1927, 254 million ounces. With an actual decrease in the amount of silver produced last year, as compared with 1928, and an increase over 1927 of less than one per cent, obviously there has been no overproduction of the metal in the popular sense. But the price of silver tells a different story. For 1927, the average quotation was 56.37 cents; it was 58.17 in 1928, and 53.0 in 1929. During the last year it reached a high point of 57 cents in January, and fell steadily, without interruption to the downward trend, to a low of 47 cents in December. Since then it has dropped to an all time low of 43 cents on February 6.

Jan 1, 1930

By Albert Ladd Colby

A GLANCE through the Bibliography appended to this paper will show that the Transactions of this Institute contain what virtually contitutes a history of the development of the manu¬facture of steel rails in this country and abroad. It is, therefore, fitting that this paper, bringing one branch of this important subject down to date, should be here presented, and it is also appropriate to select this joint meeting of our Society with the Iron and Steel Institute to compare the specifications covering the rails produced in these two countries, and to propose a standard specification to govern the manufacture of American rails for export. During the last ten years the production of Bessemer steel rails in the United States and Great Britain has amounted to 32,128,720 gross tons. Nearly 19,000,000 tons have been rolled in the past five years. The next five years will see an even larger output, owing partly to the extension of railway projects in the Orient, in South and Central America, in Mexico, and in Australia and the other British Colonies. Of late years, the American rail-mills have so largely increased their daily output, that trade conditions have often made possible the delivery of American rails to foreign ports. The tenders submitted by American mills, however, have always been accompanied by requests for changes in the foreign specifications, chiefly in the reduction of the amount of testing required; and it has only been natural, especially at first, that the engineer, whose specification had always been accepted without question by British mills, should interpret American tenders 'as an evidence that an inferior rail would be furnished

Sep 1, 1906

By H. G. HYMER

B ECAUSE of its remote geographical position and inaccessibility, little is generally known of the mining and prospecting in Northern Rhodesia. In this rather new and promising region, the development of mines presents many difficulties. Although many mineral discoveries have been made, progress in .prospecting the huge mining concessions has been handicapped by the lack of roads, communication, transportation, native population and incomplete knowledge of geology.

Jan 1, 1929