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By D. E. Norquist, J. E. Moeller

The results of wear on marked balls, 4, 31/2, 3, and 2 in. diam are given. All balls were forged steel of practically the same chemical analysis and hardness. The results indicate that balls in a given mill for a given length of time will have equal diameter losses, regardless of size.

Jan 1, 1950

Edward K. Landis, Philadelphia, Pa.: In studying Mr. Thackray's paper it seemed that a critical comparison of the results from different methods therein reported would he of interest. For this purpose Table I. was constructed by grouping all determinations made by the same method, and the probable errors were calculated. In this table all chemists titrating with permanganate (A1, E, F, G and 0 of Mr. Thackray's paper) are classed under "Emmerton;" those titrating with nitric acid (C, J, S and Y) under " Handy; " those re Probable error of result: a, ±0.0008996; b, ±0.000694; c, ±0.00107; d, ±0.00115; e, ±0.000674; f, ±0.000473; g, ±0.003675; h, ±20.0007959; i,0.000.5098; k, ±0.0008303. Probable error of single determination: a, ±0.001989; b, ±0.001547; c, ±0.00214; d, ±0.0023;e, ±0.00116;f, ±0.000818;g, ±0.0019;h, ±0.00224; i, 40.00143; k, ±0.00234. The formula for calculating the probable error is 0.6745, where N (N— 1)' S is the sum of the squares of the differences from the mean and N is the number of determinations.

Jan 1, 1897

For the convenience of members who may be trawling from place to place, the Secretary has compiled a list of libraries or other places in the United States and foreign countries here MINING AND METALLURGY or the Transactions may he consulted. This list will be sent to members if they so request.

Jan 1, 1923

[United Engineering Society ARTHUR S. DWIGHT J, VIPOND DAVIES J, V, N. DORR Engineering Societies Library Board SYDNEY H. BALL ALEXANDER C, HUMPHREYS GEORGE C, STONE JOHN H, JANEWAY Engineering Foundation Board H. M. BOYLSTON J. VIPOND DAVIES GALEN H, CLEVENGER Society for Promotion of Engineering Education WILLIAM KELLY ALLEN H. ROGERS]

Jan 1, 1928

IT is not enough to know how to melt well and to have the bellows and charcoal for your purpose. If you wish to make small castings turn out well, on account of their thinness, it is necessary to aid the metals with unctuous and corrupting materials like tin, sublimate, arsenic, or realgar,

Jan 1, 1942

For the convenience of members who may be traveling from place to place, the Secretary has compiled a list of libraries or other places in the United States and foreign countries where MINING AND METALLURWGY or the Transactions may be consulted. This list will be sent to members if they so request.

Jan 1, 1925

For the convenience of members who may be traveling from place to place, the Secretary has compiled a list of libraries or other places In the United States and foreign countries where MINING AND METALLURGY or the Transactions may be consulted. This list will be sent to members if they so request

Jan 1, 1923

By Jack White

This paper gives details of the results of careful testing carried out on two types of ball mills, conical trunnion overflow and cylindrical grate discharge, on identical ore. The object of the test work was to determine which ball mill was the most economical to install for future extensions to the Mufulira concentrator.

Jan 1, 1950

For the convenience of members who may be traveling from place to place, the Secretary has compiled a list of libraries or other places in the United States and foreign countries where MINING AND METALLURGY or the Transactions may be consulted. This list will be sent to members if they so request.

Jan 1, 1925

For the convenience of members who may be traveling from place to place, the Secretary has compiled a list of libraries or other places in the United States and foreign countries where MINING AND METALLURGY or the Transactions may be consulted. This list will be sent to members if they so request.

Jan 1, 1925

"Acta Metallurgica" Robert Madden, Dec '60 Alfred Noble Joint Prize Committee F B Foley, Dec '61 American Association for the Advancement of Science William L Fink, Dec '60, H K Ihrig, Dec '61 American Geological Institute F C Kruger, Oct '60, Thomas L Kesler, Oct '61 American Power Conference Howard A Herder

Jan 1, 1960

By B. Das, V. Hucka

Two different types of filtration methods for in-situ gasification of coal are described. The different factors, i.e., geological, technological, and others, which affect in-situ gasification are given. The layout and operation of filtration methods of in-situ gasification are described in detail. The results of a case history are described.

Jan 1, 1977

United Engineering Society ARTHUR S DWIGHT J VIPOND DAVIES J V N Dorm Engineering Societies Library Board SIDNEY H BALL ALEXANDER C HUMPHRFYS GEORGE C STONE JOHN H JANEWAY Engineering Foundation Board H M BOYLSTON J VIPOND DAVIES GALEN H CLEVENGER Society for Promotion of Engineering Education WILLIAM KELLY ALLEN H ROGERS

Jan 1, 1923

By D. E. Norquist, J. E. Moeller

The results of wear on marked balls, 4, 31/2, 3, and 2 in. diam are given. All balls were forged steel of practically the same chemical analysis and hardness. The results indicate that balls in a given mill for a given length of time will have equal diameter losses, regardless of size.

Jan 6, 1950

By A. W. Asman

An analysis is made of three different types of section production units that represent the manner in which most of the nation's bituminous coal is produced. The general delays and production characteristics of these sections are presented along with a method for evaluating section performance based on actual and theoretical production characteristics.

Jan 9, 1951

W. M. Courtis, Detroit, Mich.: Except for free-gold ores, I have always believed in scorification. I think the crucibleassay gives silver low. We found this out at the Wyandotte works in assaying Silver Islet ore. The mine-managers made us, and also the check-assayera, run one of the duplicates by

Jan 1, 1896

By Luis A. Fierino, M. Ashraf Mahtab

This paper reviews the background of, and solution techniques for, the major geomechanics problems affecting caving operations, including prediction of cavability, defining size distribution of or fragments, stability and support of production openings, and control of rock bursts and subsidence. Further research is also suggested in the solution of the various geomechanics problems.

Jan 1, 1984

By Martin C. Kuhn, Lawrence G. Stevens, J. Mark Richardson

The majority of the world's known and anticipated reserves of nickel ores are lateritic deposits At present, there are several different process alternatives for recovering nickel and other desired metal values from laterite ores An overview is given of the selective reduction roast/ammoniacal leach process, one of the processes in commercial operation.

Jan 1, 1981

By P. R. Hanes

A description of the methods used in driving two tunnels, 2 miles long each, one a 9-ft. and the other a 19-ft. diameter section, for the Owyhee Irrigation Project, Oregon. One heading of the smaller tunnel was driven 1315 ft. in 73 shifts in one month and 10,966 ft. of this section completed in ll½ months using two shifts for eight months and three shifts the rest of the time. This is a good illustration of the proper use of a mechanical shovel and the importance of careful selection of supplernentary equipment to secure best results. Large cars, speedier and heavier locomotives, 36-in. gage track of 45-lb. rail, and a good switching method increased actual shoveling time and cut down muck removal period about 45 minutes from average. The larger tunnel, after trying out standard electric revolving shovels of both the rail mounting and caterpillar tread types, was excavated with a mechanical mucker. This is the first time that a tunnel of so large a section has been handled this way. This record work was accomplished without drill carriages.

Jan 1, 1934

PREPARED BY THE PETROLEUM DEPARTMENT OF THE BOARD OF TRADE, LONDON THERE is very little to add to the report printed last year by the Institute as no developments of importance have taken place during the year. The following is a brief note on the various countries: GREAT BRITAIN The United Kingdom is a very small producer of petroleum, practically the whole output being derived from the oil-shale deposits of the Lothians of Scotland. The crude oil produced by distillation of shale in 1922 amounted to 180,000 tons, and the estimated production for 1923 is 207,000 tons. Because of the recent- decline in the market value of petroleum products, the production of oil, from shale can no longer be regarded as remunerative, and the future outlook for the industry is serious unless prices recover. As regards naturally occurring petroleum, the drilling operations undertaken by the Government have now been closed down. Out of the eleven borings undertaken only one, that at Hardstoft in Derbyshire, proved to be a producing well; its output was 125 tons in 1922 and 136 tons in 1923.

Jan 3, 1924