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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 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 AIME AIME

THIS year's Chairman of the Institute of Metals Division is a relatively rare phenomenon in the metallurgical profession; he is an expert historian of metallurgy, he is a confirmed collector and student of old works on alchemy, chemistry, and metallurgy-vide: the famous Biringuccio and he is a profound student (with a somewhat idealistic slant) of recent trends in world affairs and in what some incurable optimists call civilization; and at the same time he is still possessed of a sense of humor. Incidentally he is also one of the bestknown nonferrous metallurgists in this country and abroad, and for fifteen years has been a willing worker in A.I.M.E and the Institute of Metals Division.

Jan 1, 1943

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 Theodore Marvin

USE of airplanes to facilitate mining and petroleum operations has definitely left the "doubting Thomas" stage. As a matter of fact, front pages no longer record the novelty of this efficient arm of the mineral industry. We are now down to the facts basis. The recent aviation issue of Engineering and Mining Journal added - to our fund of knowledge on applications which the A.I.M.E. Aviation Committee is extensively adding to through its world-wide compilation of specific data. Another indication of the advance of flying in our. industries is the addition of regular aviation specialists to the staffs of various mining and petroleum companies, who function in the organization the same as do the metal

Jan 1, 1936

By Frank Julian

After the solution of an iron ore, or metallic iron, in an acid, for the determination of phosphorus, it is necessary to evaporate the solution to dryness and to heat the residue to effect the complete separation of silica. Authorities differ as to the temperature required, some recormmentling not over 100' C., others as high as dull redness. For the purpose of securing some indications as to the degree of heat which may be safely or advantageously employed, I selected a gray pig-iron, a piece of Bessemer steel rail, and a sample of Ludington ore having the following composition; the phosphorus in the pig and steel being determined by Giutl's ferric chloride method:

Jan 1, 1884

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 Theodore Simons

The rapid and comparatively recent development of flotation has opened so fascinating a field for study and research that the older processes of gravity concentration no longer receive the attention they deserve. The early work of Munroe1 and Richards,2 and the more recent contributions by Clevenger and Coe,3 Laist and Wiggin,4 Ammon,5 Bardwell,6 Crowfoot,7 and Hayden8 to mention only some which have appeared in our own Transactions-and by Schulz,9 have furnished so much data that to offer something new seems a difficult task. It is still possible, however, to present known facts from a different point of view, and, with this in mind, the writer has undertaken to express basic principles of gravity concentration in terms of simple mathematics and mechanics; the conclusions thus reached will be found to correspond, in general, with those obtained by experimental methods. Rittinger, in his classic Aufbereitungskunde (1867), reached analogous conclusions by way of intricate higher mathematics, for which reason his interesting investigations have remained a sealed book to most of us. The writer hopes that a more elementary treatment of the subject, based in part on Rittinger's methods, may, arouse new interest in the study of basic principles.

Jan 7, 1922

By A. M. Gaudin, T. P. Meloy

Based on the equation for single fracture, a formula has been obtained for repeated fracture. Solution of this equation is obtainable analytically for a few examples and numerically for all others. Graphs of the size distribution equations have been obtained; they agree broadly with the experiments of others. In another paper1 we have considered a model and a comminution distribution equation for single fracture of brittle materials. Most comminuting devices, however, depend on the occurrence of repeated fracture. This is especially true of continuous cylindrical mills of the ball, tube, or rod type. But even in primary crushers there is some repetition of the breaking process, so that this paper should be of interest in connection with all comminuting devices. HALF LIFE AND PROBABILITY OF FRACTURE To facilitate the study of fracture it is useful to introduce the concept of the half life of a particle, In the ball mill, for example, we may start with 10,000 feed particles. The time, 7, by which one half of these particles have been broken is the half life of the feed under the prevailing experimental conditions. The probability of breakage bears an inverse relationship to the half life. In a ball mill, for instance, it can be shown that the

Jan 1, 1962

By AIME AIME

THE two illustrations below, furnished through the courtesy of J. P. Messervey, Deputy Inspector of Mines, Department of Public Works and Mines, Province of Nova Scotia, show a fourth-level stope in the salt mine at Malagash, N. S. Fig. I was taken when the stope was begun, and Fig. 2 shows how it looked two months later, the photographs being taken from the came point. This stope is at a depth of about 300 ft. and is on the MacKay seam, which is the central band of white salt running through the Malagarh deposit. As run be seen. the vein is vertical. and varies from a foot to 50 ft. in thickness. The

Jan 1, 1932

By William L. Zeller

IN the past 75 years industrial engineering has been highly developed in many fields, but the coal mining industry has just begun to realize its potential for cutting costs. To receive the maximum benefit, a company should apply industrial engineering from the time a new installation is contemplated, but the principles can also be used to reduce and control the costs of an established operation. One company that had been mechanized for seven years reduced its total labor cost 57 pct by industrial engineering. Of this reduction, 20 pct was brought about by a preventive maintenance, rebuilding, and scheduled lubrication program that eliminated 80 pct of the delay caused by mechanical and electrical failures. Thirty percent of the cost reduction was attributed to rearranging the work force into crews of the most effective size, changing working methods, and training all mine supervision in the principles of the cost reduction program. The remaining 7 pct reduction was brought about by a wage incentive program for all the men in the mine. The productivity of this coal mining operation was increased from less than 8 tons per payroll man to 20 tons. This increased productivity was brought about while using the same equipment, men, and supervision.

Jan 12, 1957

By John V. Beall

Many months ago, the ME staff began thinking about what to put on the February cover of the Centennial Commemorative issue. We have considered photographs of mines, equipment, symbolic artwork and various collages. Our theme is "the next 100 years in mining" and the cover ideally should convey a related message or idea. All of us are convinced that there are many exciting technical changes that will be coming. But even so, we decided that, in our opinion, the engineer is the most vital factor. For this reason we chose to put a man on the cover of this issue. At first it was going to be the face of a man with whom each member could conceivably identify himself. It was one of the Bobs on our staff (we have four) who came up with the thought that since it's the future we are talking about, we should have a young man's or a student's face. Of course we firmed up our idea at the ninth hour, and it was too late to canvass the mining schools. However, by a stroke of luck, we were rapping with a group of University of Arizona students on the terrace of the Pioneer Hotel on December 7, 1970, and met Dave Bolles.

Jan 1, 1971

By AIME AIME

ONE unique distinction can be claimed by the new Chairman of the Coal Division, C. E. Lawall: he is the only A.I.M.E. member also a university president, though several engineering colleges are headed by Institute members. Only last year he was promoted from director of the school of mines to president of West Virginia University, following a term as acting head of that institution of over 3000 students. He was born in Catasauqua, in eastern Pennsylvania, on Nov. 21, 1891, and went to Lehigh, receiving an E.M. in 1914, and an M.S. seven years later. His engineering career began in the Pittsburgh Testing Laboratories. After three years there he came to Palmerton for

Jan 1, 1940

By M. W. Lightner

IN 1947 the steel industry rebounded from its wartime effort and produced a record-breaking peacetime tonnage of steel ingots. During the first six months of the year the industry produced 42,000,000 tons of ingots and expected to produce 85,000,000 tons for the year. With a rated capacity of some 91,000,000 tons, production was at a rate of about 93 per cent of capacity. Credit must be extended to the steel producers who have maintained this steady state of operations while faced with many problems, not the least of which was a continued shortage of satisfactory scrap. Furthermore, the steel industry started a record-breaking peacetime expansion program at a total cost of more than $1,000,000,000. This program will increase the ingot-making capacity of the country by 2,500,000 tons and should be completed in 1948.

Jan 1, 1948

By H. I. Aaronson, S. M. Kaufman, G. M. Pound

WHETHER the carbides associated with bainite precipitate from the ferritic component of bainite, as originally suggested by Davenport and Bain, or from the adjacent austenite at aus-tenite:ferrite boundaries, as proposed by Hultgren, 2 remains in dispute.3-5 A recent metallographic investigation in this laboratory has shown that the bainitic carbides formed in a plain carbon hypo-eutectoid steel nucleate entirely within ferrite at higher reaction temperatures3 and in both ferrite and austenite at lower temperatures." The present investigation was undertaken to ascertain the effects of alloying elements on the nucleation sites selected by bainitic carbides. The compositions of the steels studied were as shown in Table I. Specimens of these steels were

Jan 1, 1958

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 L. D. Clark

Pay-out, the ratio of capital expenditure to annual cash return can be very revealing when employed to gage the merits of a proposed mining venture. It is a quantity, numerically but not physically equal to a factor, by which cash return may be discounted to equal required investment. The fewer the pay-out years, the greater the average annual earning power of the project. Considerable material has been written in the past about the most important and difficult problem mining management faces in evaluation of a property: the optimum production rate for the venture. What daily capacity should be adopted for the proposed operation that it may be the most rewarding to those underwriting it? H.C. Hoover has said, "The most important objective is the least cost per ton mined; and minimum working costs can only be gained by the most intensive production." Theoretically and practically, the quicker the ore is removed, the more profitable should be the venture because of the saving in fixed charges, the consequent lower unit costs and the interest unearned by the profit from the unmined ore. Yet, such performance will be tempered by policy and a restraint imposed by the ratio of capital expenditure to annual cash return. * The 'Annual net profit after taxes but including depreciation and depletion allowances. former will be based upon an analysis of the economic climate anticipated, with its many ramifications including the demand for the product, prices, tax laws, the conduct of labor and related wage scales. The variables and intangibles involved in estimating the optimum production rate for a mine do not readily lend themselves to mathematical relationships or equations and the problem can become complex indeed. The more readily applicable and relatively faster appraisal method will be used which, in addition to being reasonably adequate in most cases, will serve as a guide, should a more expanded and detailed estimate be desired. The first question is what is company policy with respect to the rate of investment return? This will depend on that significant period of time referred to as the pay-out, which can be defined as the estimated interval during which capital investment is returned through application of annual cash return to its recovery. Expressed another way, it is the ratio of capital expenditure to the annual cash return. For example, if the capital investment is $C and the annual cash return is $A (after Federal tax), then $C/$A = the pay-out period in years. That is to say, if $C = $1,500,000 and $A = $214,000, then which is the mathematical expression for the period of time it takes to recover the funds originally invested in a mining enterprise. The relationship yp = $C/$A can be useful — an expression which requires only the significant tern yp to be fixed; in other words, the long range investment policy. For what is the pay-out period but an expression of that policy in terms of the speed, within practical limits, with which an individual or company may want to recover capital expenditure? A policy by which pay-out will be fixed is imperative. This ratio must lie within relatively narrow limits governed by what is economically feasible. It cannot be too low, rendering the ratio impractical or absurd, nor too great, delaying the return of capital for reinvestment beyond a commensurate interval. What pay-out will govern this policy? Federal corporate taxes would seem to present the best measure. Consider mining in Canada where new mines are exempt from Federal income tax for 3½ yr from date of first production. This exemption expressly allows The Act states: "A corporation . . . i s not required to include the profits . . . for the period of 36 months commencing with the day on which the mine came into production in reasonable commercial quantites." a company to recover capital expenditure during the early stages of production. With such an incentive, it is logical to strive for as much capital redemption as possible during this period. Thus, 3½ yr would be a major contribution to the pay-out in Canada. Furthermore, it generally takes from 1½ to 3 yr to develop

Jan 1, 1963

By W. C. PAGE

HARVEY S. MUDD has the unusual distinction of having virtually inherited a Directorship in the -A.I.M.E., for he was appointed to the Board to fill the unexpired term of his father in 1926. Since then he has served as a Director continuously until 1936, and now he is a candidate for Vice-President. One of the first words that young Harvey tried to say was "ore," for he was born in Leadville, Colorado, in the heyday of that camp, where Seeley W. Mudd for years ran the Small Hopes mine. Stanford and Columbia gave him his mining education, and the Shattuck-Arizona, at Bisbee, his first job. Afterwards he examined many

Jan 1, 1937

By E. DeGolyer

PROSPECTING for new deposits is a part of the ordinary routine business of the petroleum industry to an extent that is not true for any other mineral industry. The health of the industry depends upon whether we are successful or unsuccessful. How many know what it costs to find oil today and what it has cost in the past? Very few, I will wager. The industry is not well informed upon this extremely important point. We cannot deal in averages for lack of information. Does it cost more or less than previously? Prospect wells are increasingly deeper and, since the introduction of the core drill, prospecting techniques have required increasingly expensive field oper-

Jan 1, 1939

By AIME AIME

ALFRED WILLIAM GAUGER ??Al" or '?Doc" to his many friends in the coal and chemical industries- is known for his research talents and organizing ability. Appropriately the first public recognition of his technical ability was by the A.I.M.E. in the publishing of a paper by George A. Burrell and Alfred W. Gauger in the "Transactions" for the year 1916. "Al" Gauger was born at St. Paul, July 31, 1892. He graduated in chemistry at the University of Minnesota in 1914. A year later he began his initiation into the mysteries of coal mining when he joined the safety division of the U. S. Bureau of Mines at Pitts- burgh, serving from 1915 to 1917.

Jan 1, 1944