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By G. H. Kennedy

CYCLONE thickeners are "hydraulic centrifuges" designed either to produce a maximum practical separation between the water and solids of a feed slurry or to classify the slurry solids according to particle settling rate. The possibilities of utilizing the thickener to "close" plant water circuits have been investigated.

Jan 3, 1951

For the benefit of those of our members who are considerable holders of securities, but owing to their isolated situations are not in close touch with the metropolitan market and current quotations, we are publishing two very interesting graphs, showing the course of the bond and stock markets in New York over a long period. These graphs are furnished through the courtesy of the financial department of the New York Tribune.

Jan 12, 1919

By Charles P. Williams

THE determinations of the specific gravities of a number of samples of lead produced in Missouri, which form the subject of this note, were undertaken with the view of ascertaining if any approximation to the purity of such leads could be reached in this manner. The results would seem to indicate that, whatever value the method may have in the case of the crude and more impure

Jan 1, 1877

By Charles P. Williams

The determinations of the specific gravities of a number of samples of lead produced in Missouri, which form the subject of this note, were undertaken with the view of ascertaining if any approximation to the purity of such leads could be reached in this manner. The results would seem to indicate that, whatever value the method may have in the case of the crude and more impure

By S. H. Ash

Foreman remains key man in any safety program, as men attracted to the industry must be trained in safety thinking. Diesel engines underground aid safety and widespread use of roof bolting is reflected in reduction of roof-fall fatalities.

Jan 2, 1953

By B. Sadtler

The oldest producing district of Park county, and in fact one of the oldest producing gold-districts of the State, is situated on the head-waters of the Platte and tributary streams. Geo-

Jan 1, 1897

WHEN geologists began probing the grayish rock mass, natives of Adams County, Pa., called soapstone, they were paid scant attention. However, the soapstone, at first misidentified as pyrophyllite, was in reality sericite schist, a hydrous aluminum silicate whose chemical analysis resembles pyrophyllite, except that it has a slightly higher iron and potash content. In addition to its grayish color, sericite schist is foliated and has a greasy feeling much like that of talc.

Jan 10, 1953

By William P. Blake

The late Dr. Ebenezer Emmons of Albany, one of the geologists of the Survey of New York and the author of The Taconic System, brought to notice as early as 1838" a peculiar concretionary and lamellar form of phosphate of lime, to which he gave the name Eupyrchroite, from the Greek words for fire and color, with the pefix

Jan 1, 1893

By B. H. Bergstrom

In reading this article, it was difficult to follow through the example given as a starting point in the derivation of the theoretical equation which relates ball size to feed size. A discussion with F. C. Bond led to the following clarification: Bond postulates that "the breaking force exerted by a ball varies . . . as the cube of its diameter . . ." and that the force in pounds per square inch required to break a particle varies . . . as its diameter squared."

Jan 5, 1959

By K. A. Olsson

The Glenharold mine is a multiple seam dragline operation where many different stripping methods are employed. This paper describes the production operations of over-burden removal, coal loading, and haulage. Emphasis is placed on the methods used to uncover fie seam using draglines, scrapers, and a small shovel.

Jan 1, 1984

Extractive Metallurgy Division Institute of Metals Division Iron and Steel Division OFFICERS AND COMMITTEES John Chipman, President W R Hibbard, Jr, Past President C C Long, Vice-President T D Jones, Treasurer R W Shearman, Secretary AIME, 29 West 39th Street New York 18, N Y

Jan 1, 1959

By Clarence R. King

Diamond drilling of Cove Creek deposits and development of flotation-refining process may lead to commercial operation of property worked sporadically for almost a hundred years.

Jan 4, 1953

Jan 1, 1912

By I. R. M. Chatson

Radial layout's guiding principle is the grouping under one roof of the operating processes which require continuous supervision. Separate treatment sections are isolated by outside stockpiles fed with radiating conveyors. Hence the name "radial" layout. Many plants are designed with "linear" layout where successive operating stages are dotted like beads along a string of conveyors.

Jan 11, 1978

By D. A. Dahlstrom

D. R. Lyons (Republic Steel Corp., Cleveland)— Some tests using wet tables conducted by an operating company to determine the effect of table-water density on the quality of the washed coal should be of interest. The only variable during the testing period was the percentage of solids in the table water. Table operating data are shown in Table XV. The ash content of the washed coal remained constant or nearly so, as the percentage of solids varied while the sulphur content of the washed coal decreased as the percentage of solids increased.

Jan 1, 1952

INTRODUCTION The mineral sample is the fundamental unit upon which the mineral appraisal is built. Values derived from the sample are the most important quantitative measurements made in the total evaluation process. The sample value

Jan 1, 1980

By William L. Swager

This is the second in Mining Engineering's series of articles on sources, uses, production, and conservation of strategic minerals. "Cobalt" first in the series, appeared in February 1951.

Jan 5, 1951

CURRENT MATTERS Page Page New York Meeting : v 27th Engineers xl Year Book, 1918 v Professional Classes War Relief. x1i Minutes of Meeting, Board of W. S. S x1i Directors vi American Engineering Standards xlii President's Report vi Hadfield Prize xlv Local Section News: Members in Military Service... xlviii Columbia xiii Personal li San Francisco xiv Positions Vacant liii New York xvi _ Engineers Available liv Southern California xxxi Forthcoming Meetings 1v United Engineering Society xxxii Library...% lvi Engineering Council xxxv Membership lix Other Societies: Institute Committees lxxviii Mining and Metallurgical Soc- Officers and Directors lxxxvi iety of America xxxix

Jan 3, 1918

Jan 1, 1943

By R. E. Zimmerman

D. R. Lyons (Republic Steel Corp., Cleveland)— Some tests using wet tables conducted by an operating company to determine the effect of table-water density on the quality of the washed coal should be of interest. The only variable during the testing period was the percentage of solids in the table water. Table operating data are shown in Table XV. The ash content of the washed coal remained constant or nearly so, as the percentage of solids varied while the sulphw content of the washed coal decreased as the percentage of solids increased.

Jan 1, 1952