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The history of surface mining is essentially that of mining coal, copper, and iron ores and the non- metallic minerals, i.e. clays, gypsum, phosphate rock, sand, gravel and stone. The accompanying table comparing world production with that of the U. S. indicates that two thirds of the 8.8 billion tons of ores mined throughout the world come from surface operation. Assuming that the stripping ratio for surface mining in the U. S. applies equally to world production, then over 21 billion tons of waste, or a total of nearly 27 billion short tons of material are mined annually in the world by surface methods. Several factors are significant indicators of economic and technologic trends in surface mining. Among these are increasing production, a shift in emphasis from underground to surface mining, a decline in the grade and quality of some crude materials and, with few exceptions, an increase in the productivity of labor.

Jan 10, 1967

B. S. Crocker (Screened Ore Used for Fine Grinding at Lake Shore Mines, P. 499) was born in Toronto, Ont. and attended Saint Andrews College and University of Toronto. He received a B.A. and M.A. degree. He was graduated with honors and received a fellowship in metallurgy. Mr. Crocker did post-graduate research at University of Toronto from 1933 to 1934. He was employed by Beattie Gold Mines in 1933. He did research in milling at Lake Shore Mines from 1934 to 1936 and from 1936 to 1940 was head of experiment laboratory. At the present time he is mill superintendent with Lake Shore Mines at Kirkland Lake, Ont., Canada. Grinding, cyanidation, flotation and roasting are of special interest to him. He is a member of AIME. Mr. Crocker has presented several papers before C.I.M.M. and also holds membership in this society as well as Professional Engineers of Ontario. Skiing, yacht racing and photography are his favorite hobbies.

Jan 1, 1952

By AIME AIME

BORN a Chicagoan, on Aug;. 31, I879. Oscar Johnson lived in that city until young manhood. As a youth delivering newspapers he set his sight on the l university of Chicago and at sixteen years of age he began working summer vacations in the foundry of the Pullman Company. Misfortune came to his family during the summer of 1898 when tuberculosis took his only sister and brother. His mother, apprehensive of Oscar's health, urged him to try the West at least for awhile. So late summer found Oscar in Salt Lake City, employed by the Trent Engineering & Machinery Co. At that time it was busy building equipment for use in the war with Spain. Though he did not know it then, Oscar war was laying the groundwork for his present membership on the Mining Equipment Industry Advisory Committee of the W.P.B., a post which keeps him commuting between Denver and Washington.

Jan 1, 1944

By W. C. Lacy

A WIDE variety of metalliferous deposits in Peru shows a close and consistent relationship to intrusive and extrusive igneous rdcks. This relationship furnishes a clue to the comp(osition of ore-bearing fluids and to the timing in separation of these fluids from differentiation magma Conclusions presented here are based on ten years' study of a large number of metalliferous deposits in Peru. The most important of these areas are shown in Fig. 1. The structural relationship of meta1 mineralization to the intrusive series and of the members of the series to each other can be illustrated by three examples: I The well described Cerro de Pasco (Ref. 1, p. 160) sulfide mass shown in Fig. 2 is localized along the ' eastern contact of an agglomerate-filled crater. Quartz-monzonite porphyry and related intrusive breccias, which in places border the pyrite mass On west, are replaced by the pyrite and cut by later transverse vein structures. Late unmineralized but

Jan 1, 1958

By O. Bilharz

The rules laid down by Peter von Rittinger in his classic Lehrbuch der Aufbereitungskunde (Berlin, 1867, p. 513) concerning the designing of dressing-works still possess authority for such works and their operation. Nevertheless, some modifications and additions suggested by practice may be of value at the present time. Rittinger says: "I. Choose the apparatus and machines which can be, under the existing con-' ditions, easily constructed and kept in running order!' This rule contemplates the construction of apparatus (mostly of wood) on the spot, with the command of good sbops and especially of good workmen in wood. But in many cases, particularly for the sake of a prompt supply, the construction of apparatus is now left to special manufactories, which pay more attention in the choice of materials to durability and strength than to easy manipulation and erection. Nevertheless, here,as in many other instances, simplicity of construction and solidity of execution are to be recommended. Especially important is the convenient and cheap replaceability of

Jan 1, 1894

By R. P. Rothwell

A Reference to the geological map of Alabama shows the Goalmeasures of that State to form three distinct fields. The Coosu, or most easterly, contains about one hundred square miles ; the Cahaba, or middle field, which is also the most southern true coal in the United States, contains about 230 square miles ; and the Warrior field, which contains in the State of Alabama some 5000 square miles, is the southern extremity of the great carboniferous deposit, which extends through Pennsylvania, West Virginia, Kentucky, Tennessee, and Georgia. But very little has yet been done towards developing those coalfields, partly owing to the absence of all commercial manufacturing enterprise in the South under slavery, and partly owing to the want of capital and the disturbed condition of the South since the war. During the past three or four years I have devoted a large part of my time to the examination of the coal and iron ores of this range,

The mining companies on the page opposite are among the elite industrial 500 in Fortune magazine's June Directory of U. S. firms that rang up the largest dollar sales volume in 1967. The companies are listed according to their 1967 sales rank, which is given along with their 1966 rank for comparison. Mergers played an important role in the addition and deletion of several companies to the list. Tenneco, Occidental Petroleum and Gulf & Western Industries made the list of mining companies by their purchases of Kern County Land, Island Creek Coal, and New Jersey Zinc, respectively. In turn, these three companies disappeared from the list. General Aniline & Film acquired Ruberoid, and Ideal Cement is now a part of Ideal Basic Industries -a name change only. Only two companies, St. Joseph Lead and U.S. Smelting, Refining & Mining, were actually displaced from the list. The mining industry increased its sales 14.5%, placing fourth among the 22 industrial classifications listed in the Directory. However, among the ten biggest losers in sales were four mining companies-Kennecott Copper, -33.8% ; Asarco, -21.8% ; Amax, -16.5%; and Anaconda, -15.1%.-which was mostly a result of the copper strike, except for Amax which suffered strikes at its molybdenum and aluminum operations. Mining heads the list of industries for return on sales and assets per employee, while it rests at the bottom with respect to sales per dollar of invested capital.

Jan 8, 1968

By George Rice

SINCE my earliest recollection, the coal business has been in a state of unrest. It has always been a matter of bewilderment to the serious thinking, the instability of this most important industry; second only to agriculture in its effect on the great development of this country, and even more important in certain aspects, because without fuel railroads could not run, agriculture could not get its products to market, nor would the great manufacturing enterprises have been possible. I will not attempt to discuss the present serious -labor dispute or similar disagreements of the past; in the settlement of which more or less successful attempts have been made to equalize, temporarily at least, natural conditions through "joint agreement" as to prices paid labor; but will confine my views to the general underlying conditions of which the disputes are symptoms, and try to show how these must be remedied before there can be any hope of stabilizing conditions.

Jan 5, 1922

By G. C. Mudd, E. J. Myers

Within the last 15 years David Brown Gear Industries has manufactured approximately 200 large mill gears over 6m diam., 58 of them over 9 m and up to 12 m diam. The experience has not been without problems, due to a lack of clear understanding of the loads and stresses imposed on large gear wheels. American Gear Manufacturers Association (AGMA) practices suggest that a service factor be used for mill gears. But what is meant by "service factor"? The layman might be forgiven for believing that the term is synonymous with "safety factor," but this is certainly not true. The service factor is an aggregate of the following in some proportion: -An application factor, i.e., an allowance for the fact that systems do not run smoothly with uniform torque. -An ignorance factor covering the imperfections in the basic gear calculation. -Possibly a safety factor. In the following sections some of the ways in which the limits of applicability can be overstepped are discussed.

Jan 1, 1983

By John E. Riddell

This review is based on a questionnaire sent out in 1959 to 24 Canadian exploration companies, known to be active in the mineral exploration field, concerning their practice in the use of applied geo-chemical techniques in Precambrian terrains. Of the companies questioned, 21 returned completed questionnaires and of these, 15 companies stated that they had some experience in this type of work. Of the companies who stated that they had no experience in geochemical prospecting in glaciated Precambrian areas it is interesting to note that only three have reported that they do not use applied geochemistry at all. The others have reported that they make use of applied geochemistry in New Brunswick and in the Cordillera in areas of light glaciation. Their opinion is that it is a useful aid when accompanied by other techniques in evaluating mineralized areas. GEOCHEMICAL SURVEYS Table I reviews the type of geochemical surveys used by these companies, and the following points of interest should be noted.

Jan 11, 1960

By K. Koneko, T. Nokoyama, S. Shibato

SEYBOLT et al.' have detected various silica films formed on a 3 pct Si-Fe alloy after heating at low oxygen potentials with the electron diffraction method, and they have made some observations on the H,0/H2 ratios required to form them. The purpose of this note is to describe the structure of the oxide film formed on either mechanically or electrolytically polished surfaces of a 3 pct Si-Fe alloy containing small amounts of manganese after heating at low oxygen potential. The samples were prepared from a Si-Fe alloy made in the laboratory using electrolytic iron, 76 pct ferrosilicon, and 76 pct ferromanganese, vacuum-in-

Jan 1, 1969

By W. B. Lewis, M. E. True, M. C. Leverett

Tars paper states the theory underlying the design of two kinds of dimensionally scaled models of parts of idealized oil fields. One of these simulates an oil well and its surrounding sand for a distance of 16 ft. radially from the well. The other model simulates linear flow through layered sands. Construction and operation of the models are described and typical data are given. The unique features in the design of the models are: (I) the treatment of the permeability-viscosity quotient as a single variable and (2) the use of previously reported experimentally developed relations between relative permeability and saturation and capillary pressure, saturation, porosity, perm ability and interfacial tension. The models at present simulate flow of oil and water only, through unconsolidated sands. They are superior to unscaled models, which may give rise to erroneous conclusions. The models are designed to study the desirability of various methods of sell completion and the effects of various factors on recovery of oil from layered sands.

Jan 1, 1942

By H. N. Wolcott

AMONG the many cases of replacement of one mineral by another, that of quartz or silicates by pyrite, or even other sulphides, is not uncommon, but the reverse of this process does not appear to have been recorded, even if it has been observed. It, therefore, seemed to the writer that the case described below was worthy of record. FIG. I.-GROUND MASS OF CHALCOPYRITE (C) CONTAINING ROUNDED GRAINS OF PYRITE (P) SHOWING DIFFERENT DEGREES OF REPLACEMENT BY QUARTZ (Q), AND ALSO QUARTZ VEINLETS CUTTING THROUGH THE PYRITE. (PHOTOGRAPHED BY REFLECTED LIGHT.) The specimens described in this paper were obtained by R. B. Morton of Idaho Springs, Colo., from the Old Town Mine, in Russell Gulch, and are in the collection of Cornell University, where the writer studied them. In the rough, the specimens appeared to consist largely of chalcopy- rite, with some grains of tetrahedrite. The polished surface of some of

Jan 6, 1917

By Frank Foote

PRECISION lattice-constant measurements have been widely used in the study of cubic solid solutions but as yet have been rarely applied to noncubic solid solutions. (See, however, references I and 2.) With the high precision at present attainable in the measurement of lattice constants, the X-ray method should be readily applicable to noncubic solid solutions. In the work reported here, hexagonal close-packed magnesium was used as the solvent and either lead, bismuth or gold as the solute. In the magnesium-lead and mag-nesium-bismuth systems the a and c lattice constants were determined as a function of composition, densities were calculated from these lattice-constant data, these theoretical densities were compared with those directly measured and the solid solubility limit was determined on quenched specimens over a considerable range of temperature. In the magnesium-gold sys-tem, the solid solubility is very small but we have obtained an indirect check on the solubility limit previously reported.

Jan 1, 1940

SEC. 1. This Institute is incorporated under the Membership Corporations law of the State of New York; its corporate name is American Institute of Mining and Metallurgical Engineers, Inc.; and its abbreviated title A. I. M. E. SEC. 2. The objects of this Institute, as set forth in its certificate of incorporation, are: "To promote the arts and sciences connected with the economic production of the useful minerals and metals, and the welfare of those employed in these industries by all lawful means; to hold meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members the information the obtained, and to establish and maintain a place for meeting of its members, and a hall for the reading of papers and delivery of address, and a library of books relating to subjects cognate to the sciences and arts of mining and metallurgy."

Jan 1, 1939

By C. E. Birchenall, H. M. Schadel, G. Derge

EXISTING distribution data' for silicon between liquid iron and silver at steelmaking temperatures, 1500" to 1600°C, has made activity relationships in liquid silver-silicon alloys desirable as a method of determining the silicon activity in molten iron. To this end, through the use of radioactive Ag110 and the molecular beam technique described in a previous paper,' the vapor pressure of silver as a function of temperature has been measured over three silver-silicon alloys containing 3.9, 9.3, and 15.4 atomic pct (eutectic composition) silicon. The technique was that described for pure silver with the exception that a porcelain liner was used inside

Jan 1, 1951

By John Hays Hammond

IT was but a few years ago that the mining engineer, and his confreres, the civil, mechanical and electrical engineer, were stigmatized by politicians of the parish? pump variety as advance agents of unprincipled exploiters of backward countries. Today he is recognized as a most important missionary of civilization in opening up new territory to contribute its mineral wealth and incidentally its other resources for the needs of mankind. An engineer, it is now conceded, is not only a benefactor of the world at large, but is a primary factor in the betterment of conditions of the inhabitants of those countries developed by his skill and indomitable courage-for courage is requisite in pioneering and his indefatigable industry. The engineer will, I believe, become a real "Ambassador of Good Will," when the slow-consenting academic mind realizes as it must that beneficent deeds are more enduring and more convincing than mere gestures of professed amity.

Jan 1, 1929

By John D. Ridge, Betty S. Moriwaki

The significant chromite producers listed in Table I11 are not major steel producers, with the exception of the USSR. After manganese, chromium is the most important alloying metal in steel. It would not be surprising to find a direct relationship between steel production and chromite imports. The precise connection is concealed by the other uses of chromite and the grades of steel produced by the various countries involved. In addition, the amount of ferrochromium made for export must figure in any calculation. Norway, a producer of considerable amounts of ferromanganese, imports significant quantities of chromite for ferrochromium manufacture. Most of the ferrochromium is exported to European steel- producing nations. Sweden imports only half as much chromite as Norway but makes far more chromium-bearing steel. Thus Sweden has far less ferro-chromium for export, although it supplies about 2000 tons per year to the U.S. and probably some- what more to such chromite-poor steel producers as Germany and Belgium-Luxemburg.

Jun 1, 1955

SEC. 1. This Institute is incorporated under the Membership Corporations law of the State of New York; its corporate name is American Institute of Mining and Metallurgical Engineers, Inc.; and its abbreviated title A. I. M. E. SEC. 2. The objects of this Institute, as set forth in its certificate of incorporation, are: "To promote the arts and sciences connected with the economic production of the useful minerals and metals, and the welfare of those employed in these industries by all lawful means; to hold meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members the information thus obtained, and to establish and maintain a place for meeting of its members, and a hall for the reading of papers and delivery of addresses, and a library of books relating to subjects cognate to the sciences and arts of mining and metallurgy."

Jan 1, 1934

PHILIP L. GILL, New York, N. Y. (written discussion*).There is one feature of the fire-refining of electrolytic copper which I believe should be mentioned when the relation of oxygen content to the "pitch" or "set" of refined copper is under discussion; that is, the segregation of impurities. Variation of "pitch" or "set" is frequently noted in castings of different shapes, cast at the same time from the same furnace, though the oxygen content remains identical. For instance, it is possible to cast two wire-bars in the same shaped molds from the same ladleful of copper, the one 2 in. thick showing a good level set, the other, 4 in. thick, being overpoled. Also, when two bars are cast of the same weight and at the same time from the same furnace, one bar in a copper mold at the proper temperature, the other in a mold that has been allowed to get overheated, the bar in the hot mold will show

Jan 8, 1918