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By R. Steven Maxwell, Ulrich Petersen

Most minerals have experienced a slow hut perceptible decline in their annual primary production growth over the past hundred years. This decline is due to a combination of factors: (1) increased recycling; (2) exhaustion of the more accessible or higher grade ores; (3) partial substitution; (4) the more efficient use of materials; (5) progressive saturation of markets as living standards rise. Therefore, future demand for new mineral resources will probably be lower than anticipated. As the world population stabilizes, this slowdown in production growth will become even more pronounced.

Jan 1, 1979

By Harold E. Thomas, Samuel S. M. Chan, Nicholas Bada

The U.S. Bureau of Mines has developed a technique for locating and evaluating bedding plane cracks in mine roof by an air-injection and hot-film flow logging technique. It is ultrasensitive to cracks and is especially useful for detecting the early stage of crack development. Potential applications include: (1) correlation with roof sag measurements, (2) locating cracks for grouting, (3) comparison of mechanical and resin roof bolt effectiveness, and (4) possible delineation of the fracture zone to confirm the arch hypothesis. The required equipment is inexpensive and simple to operate.

Jan 1, 1975

By Rodney P. Smith

The solubility of niobium carbide in y iron has been determined for the temperature range 1000" to 1300°C from the carbon content of a series of Fe-Nb alloys equilibrated with hydrogen-methane mixtures. The method is similar to that used by Darken, Smith, and Filer 1 to determine the solubility of aluminum nitride in y iron and by smith2 to determine the solubility of niobium nitride in y iron. The samples* were strips 1.2 by 3 by 0.035 cm. The niobium oxide.* For samples of composition slightly

Jan 1, 1967

By R. E. Tate, F. W. Schonfeld

In 1899, Lebeau1 reported the preparation of the compound Lis As through reduction of lithium arse-nate with carbon. Brauer and zint12 have described the preparation of Li3 As by combining the elements in liquefied ammonia and by melting the elements in a zirconia crucible coated with lithium fluoride. In 1953, at the Los Alamos Scientific Laboratory, LisAs and a previously unreported compound, LiAs, were prepared by the reaction of the elements. PREPARATION OF THE COMPOUNDS Attempts to form lithium-arsenic compounds by

Jan 1, 1960

The surface area that mining requires is a minuscule fraction of the total land mass of the United States, according to the US Bureau of Mines' latest report "Land Utilization and Reclamation in the Mining Industry, 1930-71." During the 42-year period from 1930 to 1971, the mining industry utilized 3.65 million acres-only 0.16% of a total 2.27 billion acres of land-and reclaimed 1.46 mil- lion acres, or 40% of what it used. Which leaves, as still unreclaimed, 0.096% of the nation's total land mass.

Jan 10, 1974

By James W. Dally, William L. Fourney, Anders Ladegaard Peterson

For the past 3 years, the authors have been conducting research sponsored by the National Science Foundation (RANN) to improve the process of excavation by drilling and blasting. The approach followed has been experimental where the development of stress waves and fractures initiated at the bore hole have been investigated in order to obtain a complete understanding of the dynamic Fracture process. The second step in the approach has been to introduce modifications in the drill and blast procedure which will permit closer control of the fracture process.

Jan 2, 1978

By E. B. Thornhill

In this paper on the recovery of mercury as sulphide, from the residues from the amalgamation and cyanide treatment of high-grade ores and concentrates, I will not discuss the many reactions, chemical and other- wise, that take place in the general process, but confine myself more particularly to the methods of recovering the mercury. I submit charts of two amalgamation-barrel charges, Figs. 1 and 2, which are self-explanatory. The flow sheet of the high-grade and the mercury extraction plants is showh in Fig. 3.

Jan 1, 1916

By J. F. Pashak, T. E. Leontis

The effects of zirconium on the properties of sand cast Mg-rare earth metal alloys were discussed in detail in an earlier publication.' It was shown that a significant improvement in strength properties at temperatures up to 400°F resulted from the zirconium addition. In general, the properties of cast Mg-Didymium-Zr alloys were superior to the corresponding alloys containing Mischmetal and the optimum rare-earth level was approAmately 3 pet. Jessup, Emley, and Fisher have also shown the advantages of didymium in Mg-rare earth-Zr alloys, 2

Jan 1, 1961

By G. S. Hume

The production of petroleum in Canada is relatively small in proportion to the amount of oil consumed. Production figures are given in Tables 1 and 2, which show that the production in Alberta for 1934 was more than for the whole of Canada in 1933. The production of natural gas for Canada is shown in Table 3, In Turner Valley, the largest producing gas and oil field in Alberta, seven naphtha wells from the Paleozoic limestone and one crude oil well from Lower Cretaceous strata were completed during the year. Six-

Jan 1, 1935

By Robert Keeney

IMPORTANT recent developments in the melting and annealing of non-ferrous metals include: 1. Melting of nickel silver in the vertical ring induction furnace. 2. Electric melting of stereotype metal. 3. The rotary-drum gas-fired brass melting furnace. 4. The low-frequency coreless induction furnace. 5. Finishing annealing of brass sheets with city gas1 replacing wood. -in the large brass-rolling mill. 6. Electric annealing of brass and copper tubing and sheets. 7. Replacement of oil by gas and electricity in the annealing of nickel-silver shells and stampings.

Jan 1, 1930

By J. W. Lewis

This review covers that portion of the area between the Llano mountains and the Red River which lies between Fort Worth and Abilene. The counties and fields included are listed in Tables 1 and 2. During 1929 there was a marked lull in both prospecting and development in this part of Texas. Archer, Coleman, Cooke, Wilbarger and Young were the counties most active. The total gross production of the year was 52,611,000 bbl., 3 per cent. more than for 1928. The production of the Coleman, Cooke-

Jan 1, 1930

By C. H. Loux

THIS paper deals primarily, with the advantages realized from the adoption of methods more suitable than those previously used. The improvements noted include: (1) modification of practice in shrinkage stoping, (2) use of sublevel caving over grizzlies, (3) improved haulage and loading, (4) use of contract wages wherever possible. The Washington mine is on Jonestown Hill, one mile south of Oxford, in northwestern New Jersey. It is producing 16,000 tons of concentrates a month, which are being shipped to the Alan Wood Steel Company's furnaces at Swedeland, Pennsylvania.

Jan 1, 1933

By Ta M. Li

Expanded mine-mill capacity and greater operating flexibility are part of the dramatic changes taking place in the Tennessee mining operations of Asarco, Inc. Climaxed by the recent start-up of the $6.3 million Young mill in September 1975, Asarco has pushed Tennessee back into number one position as the leading zinc mining state. Furthermore, start-up of the Young mill is expected to insure a much-needed and continuing domestic zinc supply, at a time when US mines can only supply one-half of 1975 domestic consumption.

Jan 5, 1976

By U. W. Lisner, V. J. Hucka

Coal, which was discovered in Utah in 1849, covers about 18% of the total area. Production in 1981 was more than 13 Mt (14 million st). However, some Utah coal mines are quite gassy. If longwall face technology is applied, then release of a large volume of methane may be expected during the mining process. Investigations on methane content have been made by use of an isothermic bubble desorbometer. A desorbable methane content of 0.5 to 16 m3/t (20 to 632 cu ft per st) of coal has been determined.

Jan 1, 1985

By S. W. Ihle, L. J. Warren

A sample of garnet from the scheelite ore body on King Island, Tasmania, Australia, was upgraded and ground to produce an ultrafine portion suitable for micro-electrophoresis. X-ray and chemical analysis identified the garnet as andradite with some admixed grossular. At neutral pH the garnet particles were negatively charged, their zeta potential becoming rapidly more negative with increasing pH. An iso-electric point was found at pH 3.5. The effects on the zeta-potential of various electrolytes, hydrolyzable metal ions, and flotation collectors were also studied.

Jan 1, 1976

By K. Shoji, R. Hogg, L. G. Austin

The flow of dry powders through continuous ball mills has been investigated. Based on a physical model of the system, expressions have been derived which relate the holdup of material in the mill and its variation along the length of the mill to the mill dimensions, speed of rotation, material feed rate, and the mill discharge geometry. Experimental results obtained in a small (4 in.) mill using 3/8-in. steel balls and a feed of silicon carbide particles are in good agreement with the prediction of the model.

Jan 1, 1976

By F. C. Blake

The apparatus which I shall describe in this paper has been in ase for some time at the laboratory of the Pennsylvania Lead Company's works, and has been found to give good results, and to be simple and convenient. Steam Bath.—This steam bath is shown by Figs. 1, 2,3 and 4. It is made of sheet copper, about one-twelfth of an inch thick, the joints being brazed, and is used for heating the bottles in which the silver samples are dissolved,-previous to the fineness determina-

Jan 1, 1882

Through a unique Department of Commerce program a group of US mining equipment manufacturers spent 18 fruitful days in the, Far East, meeting with government and industry leaders in Thailand, Indonesia, and the Philip¬pines. The US Mining and Exploration Equipment Semi¬nar Mission, held April 3-20, 1979, was sponsored by the Special Activities Group of the Commerce Department's Office of International Marketing. The program included a series of technical overview papers presented by the manufacturers, aimed at promoting the sale of US products and services throughout the world.

Jan 7, 1979

Organization Place Date 1918 American Chemical Society Cleveland, O. Sept. 9-12 American Society of Sanitary En Engineers Chicago, Ill. Sept. 3-5 National Petroleum Association Atlantic City, N.J. -Sept. American Institute of Mining Engineers Colorado Sept. 2-7 National Association of Stationary Engineers.... Cincinnati, O. Sept. 9-13 Association Iron, Steel, Electrical, Engineers Baltimore, Md. Sept. 9-14 British Iron and Steel Institute, Autumn Meeting London, Eng. Sept. 12-13 National Exposition of Chemical Industries New York, N. Y. Sept. 23-28 American Electrochemical Society Princeton, N. J. Sept. 30- Oct. 2

Jan 9, 1918

By Walter Crafts

STRUCTURAL steels containing chromium have become widely used in the last 20 years. In the earlier part of this period the major applications were in chromium-molybdenum aircraft tubing and similar special high-strength steels. During the past 10 years there has been a notable expansion in the use of chromium-bearing steel for structural purposes when welding was utilized for fabrication. The chromium-bearing steels introduced by Saklatwalla1 (chromium-copper), Kinzel2 (chromium-manganese-silicon), and Schultz3 (chromium-copper) are being extensively used at the present time.

Jan 1, 1939