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By L. Ormsby, H. Lines

Drilling and blasting practices in the Morenci open pit have undergone considerable modification in recent years. Changes in the character of the ground being mined, modifications of working conditions, and continuous perimentation have been the contributing factors.

Jan 5, 1950

Jan 1, 1966

Jan 1, 1907

Jan 1, 1940

By George W. Orton

i\- number of investigations have established that tungsten monocarbide (WC) forms throughout a wide range of temperatures (800° to 2200°C), but the di-tungsten carbide (W2C) forms only at the high end of this temperature range.1"7 In addition the decomposition of WC into WzC and C at elevated temperatures has been observed.8"10

Jan 1, 1964

By J. B. Czirr, E. P. Palmer

In an effort to improve coal-mine safety, a spectrum analyzer was used to make a detailed examination of the vibration frequencies produced by tapping a mine roof. We show that spectral analysis can be used to distinguish between "solid" and "drummy" roofs to a degree approaching that of the human ear, but it can reveal little about roof-slab thickness or attachment. We recommend research into the utility of augmenting human hearing in roof testing and into utilizing microseismic emissions to help assess roof integrity.

Jan 1, 1983

Jan 1, 1962

Jan 1, 1897

By C. G. McLachlan

Laboratory flotation tests carried out on massive sulphide ores may not be reproduced in plant practice, and when this occurs the discrepancy can be the result of differences between laboratory and plant grinding. Results of parallel flotation tests are given to support this contention, and data show how tailing losses are affected in corresponding size zones.

Jan 4, 1951

Jan 1, 1940

W. M. PEIRCE, Chairman J. L. CHRISTIE, Past-chairman E. H. DIX, JR., Vice-chairman ALBERT J. PHILLIPS, Vice-chairman E. M. WISE, Secretary International Nickel Co., Bayonne, N. J. W. M. CORSE, Treasurer Executive Committee W. H. BASSETT, JR. R. H. LEACH' D. K. CRAMPTONR. F. MEHL J. A. GANN W. E. REMMERS G. O. HIERS H. J. ROAST JEROME STRAUSS Finance Committee J. L. CHRISTIE, Chairman W. M. CORSE C. H. MATHEWSON T. S. FULLER H. S. RAWDON

Jan 1, 1934

By G. W. Mao, A. M. Gaudin, D. W. Fuerstenau

Jan 1, 1960

By Major William R. King U. S. Engineer

My attention was drawn to this subject just twenty years ago this month, when I was detailed to rebuild one of the bridges in Richmond that had been burned during the evacuation. We took pos

Jan 1, 1886

Executive ARTHUR S DWIGHT, Chairman B THAYER CHARLES F RAND P MATHEWSON J V W REYNDERS Membership WILLIAM H BASSETT, Chairman W Y WESTERVELT Vice-chairman P MATHEWSON H G MOULTON F T RUBIDGE Finance WALTER H ALDRIDGE, Chairman GEORGE D BARRON GALEN H CLEVENGER

Jan 1, 1923

By A. B. Wood

In welding and metal working by electricity, two systems are in use,—the so-called. incandescent system, in which the material operated upon is traversed by currents of large volume and low electro-motive force, the current having a continuous metallic circuit during the welding operation, and the arc system, in which the electric arc is utilized. It is the purpose of the present paper to call attention to this last

Jan 1, 1892

By Phyllis A. Lyday

Jan 1, 1985

Jan 1, 1934

By P. W. Shimer

The purpose of this note is to call attention to a source of error in the determination of graphitic carbon, made by the usual method of solution in hydrochloric acid. Although the method is tedious, because of the necessary treatment of the separated carbon with caustic potassa, alcohol and ether, the text-books seem to give it preference; and it is, perhaps, used more generally than the method of solution in dilute nitric acid. Solution in hydrochloric acid usually gives higher graphitic-carbon results than solution in nitric acid, and many, therefore, consider it more trustworthy, the inference being that the lower results obtained by nitric acid are due to the loss of some of the finely-divided graphite by reason of the oxi-

Jan 1, 1896

Univ of Alabama-University, Alabama-Mining and Metallurgical Society William L Mason, Faculty Sponsor, E C Wright, Dept Head Univ of Alaska-College, Alaska-Mining Society of the Univ of Alaska Douglas W Huber, Faculty Sponsor, E H Beistline, Mining & Metallurgy Dept Head, Troy L Pewe, Geology Dept Head, James Crawford, Chapter Counselor Univ of Arizona-Tucson, Arizona-Miners Society Willard C Lacy, Faculty Sponsor, J D Forrester, Mining & Metallurgy Dept Head, F W Galbraith, Geology Dept Head Univ of California-Berkeley, California-Mineral Technology Association H E Hawkes, Faculty Sponsor, Joseph A Pask, Dept Head

Jan 1, 1959

By Desmond Y. M. Lee

Computerized preventive maintenance has been a long sought goal in many industries. People have firmly believed that proper implementation of such a system can result in tremendous saving of money. However, the preventive part has always been left out without realizing it due to the inflexibility of coping with environmental changes. With this in mind, the Iron Ore Company of Canada has developed a computerized system which schedules maintenance jobs preventively.

Jan 1, 1977