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By N. B. Davis

I . INTRODUCTION WHILE working with a number of very sticky cracking clays from western Canada the writer became interested in a study of the cause of the excessive plasticity, This led to a review of the rather bulky literature on the subject and the finding that plasticity still remains to be satisfactorily explained. Most of these investigations seem to have been carried on solely from the chemical viewpoint, the geologic aspects having been ignored. In nearly every case, the investigators have worked with the higher-grade clays of low to medium plasticity, such as the kaolins, the excessively plastic ones having generally been neglected, partly because of their limited application, yet the author believes that these are

Jan 2, 1915

By Theodore Simons

I. INTRODUCTION PERMISSION to present this paper at the February, 1915, meeting of the Montana Section of the American Institute of Mining Engineers was liberally granted by W. A. Clark, Jr., President and General Manager of the Timber Butte Milling Co., and by the representative of the Minerals Separation Co. For the many courtesies shown the writer on his visits to the mill and for information supplied, he is indebted to all the officers of these companies, especially to W. N. Rossberg, W. D. Mangam, Hamilton Cooke, Jr., T. M. Owen, T. C. Wilson, R. McGillivary, L. L. Quigley, C. Bartzen and others. The writer takes this opportunity to herewith express to them his appreciation and sincere thanks.

Jan 6, 1915

By F. Lynwood Garrison

The enormous growth of the manufacture of Bessemer steel in this country within the last few years, due to the almost constant large demand for steel rails, renders it very desirable that our knowledge of the physical and chemical properties of a material upon which we place so much dependence should be increaqed by every possible means. It was with this end in view, and also in hopes of learning something of the causes affecting the regularity of the Bessemer product, that I took up the subject of this paper a short time ago. The lise of the microscope as an instrument of research in the metallurgy of iron and steel is now fairly well established;

Jan 1, 1887

By Thomas Robins

About six years ago the writer had occasion to visit a large magnetic iron-ore concentrating-plant, and then saw for the first time rubber belts employed for conveying-purposes. These belts were from 20 inches to 30 inches in width, and some of them were as long as 500 feet between centers. When I spoke of the enormous amount of material they handled with a small expenditure of power, the superintendent assented, but at the same time complained that although he bought the best quality of belts, the abrasion of the ore wore them out very rapidly, causing continually very large bills for repairs and renewals. On close examination several interesting points were discovered :

Jan 1, 1897

By C. R. Garr, A. R. Troiano

FLAKING or hair-line crack formation has been a major problem confronting the producer of large alloy steel forgings.' Today it is generally conceded that hydrogen in one or more forms in alloy steel sections is a requisite for flaking. Hence an obvious remedy is a thermal cycle that reduces the hydrogen content to some low level. In practice, this generally means holding the material at some subcritical temperature for a period of time depending on the size of the ingot or forging. Another method that will suffice in some cases is to cool large forgings slowly, i.e., bury in ashes. In practice, this hydrogen bake is sometimes accemplished inadvertently by a series

Jan 1, 1958

By W. W. Roepke

One phase of Bureau of Mines research deals with reduction of primly respirable dust generated by bit cutting action at a coal seam face. This paper presents a summary of coal cutting technology addressing this problem. All aspects of the cutting system affecting miner health and safety are discussed. Cutting design concepts are considered that minimize dust generation, energy used, and Ignitions, while maintaining production. With present equipment, an operator can maintain production and minimize dust energy and conditions by cutting at maximum depth (maximum sumping or advance rate) at all times, at minimum rpm with fewest possible bits, and with lowest possible included bit tip angle, i.e., minimum bit wear.

Jan 1, 1985

By Thomas Fraser

BECAUSE of the present interest in the subject of sulfur in coal and its removal, such information as is available in the coal-washing literature on the various factors that determine the adaptability of a coal for wash- FIG. I.-COAL-WASHING TABLES OF ONE-FOURTH COMMERCIAL SIZE. ing have been collected and are presented here together with some observations based on results of experimental work carried out in the coal-washing laboratory of the mining department of the University of Illinois, and investigative work at Illinois washeries in connection with the work on reduction of the sulfur content of coal, being carried on at the Urbana Station of the.U. S. Bureau of mines. This investigative

Jan 9, 1919

By Ralph D. Parker

A STRIKING testimonial to the value of safety was contained in an ad- dress given in May, 1936, by A. R. Young, vice-president of the United States Steel Corp.: In the period from 1906 to 1935 we have spent $24,860,540 on safety work. By comparing the cost of "prevented" accidents by the cost of settling similar accidents, we found that we had made a saving of $117,224,238. Even if those figures are 50 per cent wrong, at least we got back every dollar we paid for safety and another with it. I don't think anyone has to blush before his board of directors for an investment of that kind.

Jan 1, 1937

By Philip D. Pearson

IN recent years, there have been many changes in mining operations in the Lake Superior district. To follow these trends on the Menominee Range of Michigan, information has been assembled from all of the iron mining operations in the area. There are 15 operating underground mines in the Iron River-Crystal Falls area of the Menominee Range. Within the past two years, two idle properties were re- opened and are now producing, and a third and fourth are being reopened. Also, there are two siliceous openpits operated by independent companies outside this immediate area. Six companies operate the underground mines, employing some 1850 employees. Table I shows pertinent facts about these properties.

Jan 4, 1951

By D. M. Francois-Bongarcon

The idea of parameterizing reserves has only been formalized and scientifically applied for a few years. Its most fully developed application, that of open pits, has been operational only since 1976. Two new versions which have just been issued provide a complete solution to the problem and also a powerful tool for mine planning, and they open up a new field of investigation. This paper describes the basic principles for parameterizing reserves, their application for open-pit mines, the algorithm used, the physical interpretation of the results obtained, their economic use as well as the first prospects offered by a complete parameterization in tm of (I. ti), or of the metal price.

Jan 1, 1984

By C. C. Spencer

A CHARGE of 12,200 lb of scrap was used on all heats. The slag materials that were added to the furnace along with manganese ore were kept constant; that is, 230 lb Coxey sand was put on the banks at the slag line before each heat was charged, 35 lb limestone was added after the carbon boil. manganese ore was the only item varied in the four series described herein. I might add here that it is impractical for us to get the carbon clown in one boil, for the steel would come out through the doors and run over the floor. We take the carbon down in two vigorous boils.

Jan 1, 1947

By R. W. Raymond

Some months ago I heard from a party of returned tourists an amusing story of a Chinese laundryman in the National Park who had included in his cabin a hot spring, of which he was accustomed to avail himself in his business, and who, on one occasion, having thrown a lot of linen into this spring to soak overnight, had added a piece of soap to facilitate the process, and had been considerably surprised when, stimulated by this soap, the spring had suddenly become a geyser and wrecked his establishment. The story went on to say that the practice of "soaping" geysers to make them, active had become general, but had been forbidden by the authorities.

Jan 1, 1889

By R. Maddi, I. R. Kramer

C. S. Roberts (Dow Chemical Co., Midland, Mich.)— In this study we have seen another example of how modern electronic instrumentation can be of great value to metallurgical research. The authors have shown much ingenuity in their experimental work. However, I wish to point out that anelasticity theory tells us that we must be cautious when we use pulse methods for measurements which are to be correlated with knowledge of static stress-strain behavior. The basic stress calibrations used by the authors depend on the use of static moduli combined with the pulsed strains. No recognition of a possible modulus defect has been indicated. The general agreement of critical resolved shear stresses may indicate that a

Jan 1, 1953

By Joseph G. Wargo

A meteoric rise in selling price has revived gold exploration activity throughout the world. In the United States the effort is, in large measure, channeled toward discovery of disseminated gold deposits such as the Carlin-type, i.e., with size and grade characteristics similar to Newmont's Carlin mine in Nevada. The subtle surface indications characteristic of Carlin-type gold mineralization have been examined by a number of geologists, and the more obvious prospects have been tested by surface sampling and drilling. It is likely that most of these readily recognizable deposits have already been found and, as a consequence, prospectors are now entering a new, second stage of exploration for Carlin-type and related disseminated gold deposits.

Jan 9, 1979

Frank Williams, Johnstown, Pa. (Communicatioll to the Secretary): As the manager of the company which manufactured the " American " magnesite and the silica-brick mentioned by Mr. Pennock, I beg to say that he was quite right in placing a mark of interrogation after " American " (page 268). While the users of magnesite in this country are at a disadvantage as to cost by reason of not having any large bodies of sufficiently pure material at hand, the manufacturing concern referred to has secured an advantage as to quality by a mixture of the different foreign magnesites, which vary considerably in their composition and physical structure. The American (?) magilesite tested was a sample of the next

Jan 1, 1897

By H. K. Shearer

There is little of importance to be added to the production record of south Arkansas, north Louisiana and Mississippi as a result of developrnents during 1931. No discoveries of any probable commercial value were made, and the only additions to proven acreage were extensions to the Zwolle producing area. " Includes 29 parishes: Avoyelles, Bienville, Bossier, Caddo, Caldacll, Catahoula, Claiborne, Concordia, De Soto, East Carroll, Franklin, Grant, Jackson, LaSalle, Lincoln, Madison, Morehouse, Natchitoches, Ouachita, Rapides, Red River, Rich-land, Sabine, Tensas, Union, Vernon, Webster, West Carroll and Winn. Tables I and 2 show the number of wells completed in 1931 in 25 counties of south Arkansas and 29 parishes of north Louisiana, with the

Jan 1, 1932

Papers in Classes A-Metal Mining, B-Milling and Concentration, H-Indus¬trial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Papers in Classes C-Iron and Steel Division, D¬-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. Papers in Class G-Pe¬troleum Division are distributed in PE¬TROLEUM TECHNOLOGY, which is issued every other month. TECHNICAL PUBLICA¬TIONS in Classes F-Coal Division, J¬-Mineral Industry Education Division, K¬-Mining Administration, and 1-Geophysics, are issued as separate pamphlets. Contributions are papers that when printed or mimeographed are available but only on request.

Jan 1, 1943

By P. Somasundaran Discussion by Knut L. Sandvik

Knut L. Sandvik (Mining Engineer, Mineral Dressing Laboratory, Technical University of Norway, Trond-heim, Norway) — The discovery that adsorption at solid-liquid interfaces is influenced by adsorption at other interfaces may prove very fruitful in the further development of flotation theory. Having reached the same conclusions as P. Somasundaran in some experiments with amine hydrochlorides, I would like to offer more direct evidence of the interfacial adsorption mechanism based on surface tension measurements and adsorption studies.' This evidence was derived from flotation tests carried out in a Hallimond tube at neutral pH and 60°C. The amount of amine solution and quartz surface were chosen to insure measurable concentration changes during flotation due to adsorption. Adsorption data for

Jan 1, 1969

By Magnus Troilius

The heat-calculations of gas-analyses involve cumbrous multiplications, which are apt to lead into errors. The foliowing tables and formulae have been found useful as facilitating such calculations, and therefore I hope that they will be of interest to some of the members. By "heat-unit" will, in the following, be understood the amount of heat required to raise the temperature of 1 kilogram of water l° Cent. All the tables refer to cubic meters at O0 and 760 mm. pressure. The following gas is chosen as an example: C02, - 4.0 vol. per cent. co, = 20.0 " CHI, - 3.5 " H, - 7.0 " N, - 65.5 " " 100.0

Jan 1, 1884

By W. H. Hoffman

The writer does not claim a right to discnss this subject as a furnace-man or user of iron-ore in this new form. His efforts have been confined to mining, preparing, and separating the magnetic ore from the gangue. Two years' experience in experimenting and another two years in producing concentrates on a commercial scale, have led me to believe that the new trade of making concentrates must be well learned in all of its details. If there have been any partial failures in this most useful branch of the iron business, the failures have been caused chiefly by inexperience or lack of patience. Although I have, within the past five years, constructed machinery

Jan 1, 1892