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By D. S. Hutton, W. C. Leslie

S. Floreen (1nteumtio)lal Nickel Co.)— One fairly simple way to differentiate between embrittlement due to surface microcracks or due to a dislocation barrier effect might be to load a brittle rock salt crystal in tension to some stress just below the fracture stress and then immerse the loaded crystal in water. If a surface film is retarding plastic flow then one should observe some plastic deformation of the rock salt as

Jan 1, 1962

By M. P. Nackowski

Geological engineering expanded its role and significance during 1966 in the areas of construction, raw materials exploration and inventory, water supply and pollution, mechanical properties of earth material and regional environmental planning. Efforts varied immensely in scope and magnitude, in simplicity, difficulty and importance. Observations, measurements, and analysis encompassed both simple and sophisticated procedures. CONSTRUCTION Activities in construction ranged from preliminary to detailed evaluations of sites, development of preventative measures and designing corrective measures following construction failures. Most investigations concerned dam sites, highway locations and slope stability, building sites, tunnels and underground storage facilities.

Jan 2, 1967

By Robert L. Marovelli

A recent reorganization placed the health and safety research activities of the Bureau of Mines under a director, Division of Minerals Health and Safety Technology. The new health and safety research organization and its position in the Bureau hierarchy is shown in Table 1.

Jan 11, 1979

Tourism is the second largest industry in the Tasmanian copper mining center of Queenstown, Australia, but it is not the historic mine the tourists come to see. The attraction is rather the devastation the mine has brought to the surrounding countryside which has made Queenstown literally the most colorful mining town in Australian history.

Jan 6, 1972

By Robert W. Bruhn

An investigation was made of ground response to pillar retreat mining in a 1.7 meter thick seam at 108 meter depth at a site in northern West Virginia. This paper describes mining-related stress changes and movements at mine level, displacements within the overburden, ground surface subsidence and groundwater level variations. Subsidence approached 40 per cent of the mine height and continued more than a year after mining. Water levels declined in certain deep-lying strata.

Jan 1, 1984

By E. P. Pfleider, C. A. Dufresne

The problem of mooing open-pit ores over large vertical distances is increasing in importance because of the immense deposits being mined. Gravity fall of ore through transfer raises to central haulage points underground has advantages for certain open-pit operations, and this method is being seriously considered for the Carol Project now underway in Canada.

Jan 6, 1961

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1917

By W. L. Hill, W. H. Armiger, S. D. Gooch

The physical properties, chemical behavior under thermal treatment, and fertilizer value of fluorine-containing pseudowavellite (hydrous calcium aluminum phosphate) that occurs as phosphate clay admixed with quartz sand in an extensive deposit near Bartow, Fla., were determined by experiments in laboratory, pilot-plant, and greenhouse. When the mineral was heated at 500°C, 80 pct of the phosphorus became citrate soluble. The heated product, however, deteriorates markedly under moist conditions such as obtain in the soil.

Jan 6, 1950

IRON AND STEEL COMMITTEE. ALBERT SAUVEUR, Chairman. A. A. STEVENSON, Vice-Chairman. HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Cambridge, Mass. John Birkinbine, William Kelly, J. S. Unger, William H. Blauvelt, Charles Kirchhoff, Felix A. Vogel,. James Gayley, Richard Moldenke, Leonard Waldo, Henry D. Hibbard, Joseph W. Richards, William R. Walker, Henry M. Howe, C. F. W. Rys, William R. Webster, Robert W. Hunt, E. Gybbon Spilsbury, Frederick W. Wood: J. E. Johnson, Jr.,

Jan 12, 1913

(Under this heading will he published notes sent too the Secretary of the Institute by members or other persons introduced by members.) Management or superintendency desired by member, graduate mining engineer of large practical experience in the details of mining, milling, concentration and cyaniding. Experienced in the efficient mechanical equipment and operation, and in the general business management of a mining property. No. 444. Metallurgist and operator who has specialized in the hydrometallurgy of. gold and silver, particularly stamp milling and cyaniding, desires change from present position. Ten years' experience in Western U. S. Thirty-six years old, married, in best of health and will go. anywhere. Available in 30 days. No. 445.

Jan 4, 1918

By R. G. Ward, John Henderson

It has been shown1 that the observed density1-' of liquid iron silicates in contact with solid iron depends upon whether nitrogen or argon is used to protect the experimental system from oxidation. These densities have been measured by the maximum bubble-pressure method, in five different labora-

Jan 1, 1965

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

While great strides have been made in the machinery for mining rock on the surface of the land, comparable advances have not been made with underground equipment. In fact, excavation of underground openings has actually declined in importance. On the other hand, surface mines are getting deeper and approaching the economic limits at which they can be worked. In the face of these approaching limits and the added problem of escalating labor costs, James Boyd, President of Copper Range Corp. and AIME, has suggested that "science and engineering must come to grips with the need for making subsurface openings more quickly and cheaply.

Jan 10, 1969

By T. F. Adams, L. G. Margolin

The Bedded Crack Model (BCM) is a constitutive model for brittle materials. It is based on effective modulus theory and makes use of a generalized Griffith criterion for crack growth. It is used in a solid dynamic computer code to simulate stress wave propagation and fracture in rock. A general description of the model is given and then the theoretical basis for it is presented. Some effects of finite cell size in numerical simulations are discussed. The use of the BCM is illustrated in simulations of explosive fracture of oil shale. There is generally good agreement between the calculations and data from field experiments.

Jan 1, 1982

By H. Firmstone

Deposits of cadmia, or impure oxide of zinc, are of common occurrence in the upper parts of blast furnaces using ores containing zinc, and were very common in the charcoal furnaces of Virginia working the brown hematite ores found near the Cadent black slate. These deposits were known to the old charcoal founders as "sulphur rings," and the characteristic green flame of burning zinc frequently to be seen at the tymp of furnaces working ores containing zinc, was held by them to indicate the presence of a "sulphur fall." When zinc is burning in considerable quantities at the tymp, the

Jan 1, 1879

By Claudio Gutierrez

It has been claimed (Eadington and Rosser, 1969) that when freshly precipitated lead sulfide is in contact with oxygen-containing water, there is an "induction period" of at least a few hours during which no detectable oxidation of the lead sulfide takes place This effect would be of the utmost importance for the adsorption of xanthate on galena in flotation mills. It was tried here to reproduce the results obtained in (Eadington and Rosser, 1969), but no "induction period" was found. Besides, reasons are given to prove that the oxidation mechanism proposed by Eadington and Prosser (1969) is not realistic.

Jan 1, 1982

By Shiou-Chuan Sun, R. F. Wesner, J. D. Morgan

A new apparatus termed a "distribution analyzer" is introduced to ascertain the optimum conditions of electrostatic separation of minerals. It was found that with similar surface condition, testing environment and a constant feed rate of not higher than one layer of particles fed on the grounded roll of the separator, the behavior of each component mineral in a synthetic mixture or ore is roughly similar to that of the same mineral when tested alone.

Jan 3, 1950

By Victor Phillips, J. P. Blair

Jan 1, 1952

By G. W. Toop, C. S. Samis

Jan 1, 1962

By B. R. Palmer, G. Gutierrez B., M. C. Fuerstenau

Flotation responses of chrysocolla and rhodonite are correlated with electrophoretic mobility and infrared spectroscopy measurements. Flotation is effected in the pH ranges in which hydrolysis of the metal ions comprising the mineral occurs. The roles of mineral solubility and precipitate formation are suggested.

Jan 1, 1976