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By R. L. Tobie

Handling and storing ore at transfer points underground are encountered frequently. An ideal solution to these troubles is probably still to be found, but at the Mather mine "B" shaft a method incorporating scraping trenches has been developed giving better service, from the standpoint of safety and simplicity, than obtained from other schemes. When shaft pockets are used for storage, the size of the ground opening required to assure capacity is often prohibitive, and shaft depth below the last level can become excessive, particularly if a crushing station is used. Also, if the material being handled contains large amounts of wet fines, it is difficult, if not impossible, to hold the material with regular chute gates. In order to remedy these problems Cleveland-Cliffs' Mather "B" has utilized three types of trenches. Types I and I1 are now in service and the third is under construction.

Jan 4, 1955

By R. S. Sandhu, S. H. Advani, J. K. Lee, B. L. Aboustit

A comprehensive finite element formulation for thermo-elastic consolidation based on a general variational principle is presented Sample one dimensional problems associated with isothermal consolidation, heat conduct ion, and thermo-elastic consolidation are presented. In addition, evaluations of thermo-elastic consolidation for an underground coal conversion field site are conducted.

Jan 1, 1982

By H. J. C. MAC DONALD

THE mining engineer must have a chest of books snug enough for a camelback or to be stowed away in a canoe; at the lowest possible cost, as he needs it the most in those early years when he earns the least; but at the same time one having an unusually wide range, for he may have to cut down a forest, put up a sawmill, build mine towns, construct dams, power houses, power lines, and railroads. In fact he may be called upon for many unexpected accomplishments and all in extension of the characteristically broad demands of his profession. Suppose that an average mining engineer with a thorough theoretical training and a specialized mining education has accumulated, during a cosmopolitan experience, a complete and up-to-date library, but, unfortunately, in accepting a long term assignment to a far country he is forced to discard the greater part of

Jan 1, 1925

J. J. CARRIGAN, Butte, Mont. (written discussion*).-I think all who have had experience in the operation of metal mines will agree with Dr. Lanza that many improvements can be made in the underground workings to improve health conditions. Physical examination would no doubt be a good thing and would do a great deal in abating the diseases now so common among metal miners, but I cannot see how it would be possible to put this examination into practical working order. Dr. Lanza says, "For the sake of argument, this physical examination should be under state supervision." I think if, this were attempted it would result in nothing but argument. While such a law possibly could he passed in a few states, I feel certain that in the greater number the miners would fight such legislation with the same determination that they would

Jan 4, 1919

By Hubert O. DeBeck

The following descriptions and explanations apply specifically to the use of the Hotchkiss Superdip, but there are no apparent reasons why they should not apply to any magnetometer. This paper is a product of work in the practical field for several years with the Hotchkiss magnetometer, mostly on mineral deposits in the southeastern United States. The paper describes the result of an attempt to develop a practical and economical field method that approaches, as nearly as possible, the utmost accuracy of which the magnetometer is capable. As there are many published descriptions of various magnetometers and magnetic methods, it would be superfluous to describe such instruments here, but a limited bibliography on the Hotchkiss and Askania magnetometers is appended. The Hotchkiss and the vertical Askania magnetometers have, respectively, maximum sensitivities of approximately 5 and 30 gamma per instrument scale division. Purpose of New Method The purpose of the method described in the following paragraphs is to eliminate, as far as possible, all corrections of field data that cause complexities and inaccuracies in the results of magnetometer surveys. Magnetometer field observations must be corrected for periodic variations in the intensity of the earth's magnetic field, as well as for temperature variations, both of which take place during the course of a day. These variations do not seriously handicap magnetometer work on highly magnetic deposits, but it is impossible to obtain accurate results, by the conventional methods in use today, over weakly magnetic or diamagnetic deposits. This is due to the physical inability to obtain by such methods sufficiently accurate data in the field to make dependable corrections. The magnitude of the necessary corrections of field observations frequently exceeds the magnitude of local magnetic anomalies obtained over various types of mineral deposits. Therefore if these corrections are neglected or made on the basis of inaccurate data, the entire magnetic picture of the area concerned is at least distorted, and perhaps destroyed altogethcr.

Jan 1, 1934

By A. Faber du Faur

At the request of some of the members to whom I have shown a collection of specimens of sulphur from southern Utah, I herewith present some notes relating to the mines and the method of extracting the sulphur from the ore. In preparing these notes I have borrowed from a paper by Prof. G. vom Rath, published in the Neue Jahrbuch fur Mineralogie, vol. i., 1884, dated Salt Lake City, December, 1883. The Cove Creek sulphur-bed, now worked by the Dickert & Myers Sulphur Co., is in Beaver county, near the line of Millard county. It was first discovered by Mr. Ferdinand Dickert in 1869 ; other beds in the same neighborhood mere found by him from 1872 to 1875, making altogether 22 mining claims. The want of railroad communication prevented the early development of these claims; but in 1883 Mr. F. Dickert put up a plant for extracting sulphur from the ore, which proved a perfect success; and in 1885 the property was transferred to a stock company organized under the laws of Utah. The railroad station nearest to the Cove Creek mines is Black Rock, on the Utah Central Railroad, 204 miles south from Salt Lake City, and about 26 miles west of the mines. The road from Black Rock to the mines passes through desert and lava-bed, to the road leading from Kanosh to Beaver, which latter road it joins near Cove Creek fort, a square stone enclosure, erected by the Mormons for protection against the Indians. Cove Creek fort is situated near the eastern limit of a plain bounded on the west at a distance of about 12 miles by the Mineral range, and on the east by the Sulphur mountains, forming part of the Tushar mountains. To the northwest the plain runs into the Sandy desert. About 3 miles from the fort rises a solitary hill about 1000 feet above the

Jan 1, 1888

By Lewis M. Haupt

IT has given me great pleasure to read, in the papers recently published by this Society, the discussions on the subject of Technical Education, which were developed at the joint meeting held at the Franklin Institute in June, 1876; and since it was impossible for me to be present, I desire to improve this my first opportunity of adding the weight of my testimony and experience to what has been so ably presented by others. It is a subject about which the people need to be kept agitated, that their views may expand with the demands made for a higher and more thorough education. It is the public at large, the capitalist, the manufacturer, and the laborer, who are to be benefited more or less by this elevation of the standard of our professional schools, and it is but just, therefore, that the schools should look to them for the means with which to accomplish so desirable an object. It is no doubt to the interest of a metallurgist to employ a skilled laborer who will prevent waste by properly proportioning his materials ; by regulating the supplies of air and fuel ; by arranging his plant in the most economical manner, and by disposing of his products to the greatest advantage. The engineer is benefited by selecting for an assistant a person able to determine the values of his factors of safety for the same materials in different forms and positions, avoiding expensive suits for damages and cost of reconstruction; he should be able to so locate a road as best to fulfil the requirements of a through traffic, and yet develop local industries. But I need not multiply instances to show what all will readily concede, viz.: the advantages of a theoretical education ; that was fully demonstrated at the previous special meeting, but it is still an open question whether the practical instruction should precede, accompany, or follow the theory.

Jan 1, 1877

By William I. Watson

Problems encountered in beneficiating mineral raw materials become increasingly difficult as there is a shift to lower grade and more complex raw materials, and because of the economic need to strive for ever higher recoveries, higher grade products, and lower processing costs. Methods of attacking the many problems should include not only the familiar chemical and physical tests and equipment, but such techniques as X-ray analysis, infra-red analysis, differential thermal analysis, and the use of electron and X-ray microscopes. Many people in the mineral-treating field are unfamiliar with these newer methods and techniques. The differential thermal analysis method, in particular, does not seem to be very well known, even though it offers interesting possibilities in the study of many ore treatment problems.

Jan 7, 1959

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Jan 1, 1942

By Lewis M. Haupt

IT has given me great pleasure to read, in the papers recently pub lished by this Society, the discussions on the subject of Technical Education, which were developed at the joint meeting held at the Franklin Institute in June, 1876; and since it was impossible for me to be present, I desire to improve this my first opportunity of adding the weight of my testimony and experience to what has been so ably presented by others. It is a subject about which the people need to be kept agitated, that their views may expand with the demands made for a higher and more thorough education. It is the public at large, the capitalist, the manufacturer, and the laborer, who are to be benefited more or less by this elevation of the standard of our professional schools, and it is but just, therefore, that the schools should look to them for the means with which to accomplish so de sirable an object. It is no doubt to the interest of a metallurgist to employ a skilled laborer who will prevent waste by properly proportioning his ma terials ; by regulating the supplies of air and fuel; by arranging his plant in the most economical manner, arid by disposing of his products to the greatest advantage. The engineer is benefited by selecting for an assistant a person able to determine the values of his factors of safety for the same materials in different forms and positions, avoiding expensive suits for damages and cost of reconsiruction; he should be able to so locate a road as best to fulfil the requirements of a through traffic, arid yet develop local industries. But I need not multiply instances to show what all will readily concede, viz.: the advantages of a theoretical education ; that was fully demonstrated at the previous special meeting, but it is still an open question whether the practical instruction should precede, accompany, or follow the theory.

By C. Baldwin Sawyer

J. S. Vanick,* Washington, D. C. (written discussion).—To those who have been confronted with the study of the gas-metal reactions, this paper is a most welcome contribution. My personal interest in work bearing upon this general problem, stimulated by an appreciation of the difficulties inherent to problems of this type, prompts a few words of discussion. Table 2 of the paper shows a gradual increase in the nitrogen content with an increase in pressure, and an interpretation follows in which nitrogcn is used as the compressed medium when the conditions admit that cyanogen gas could be active as a contaminating ingredient. Fusions of electrolytic iron made in the induction furnace in an atmosphere of deoxidized nitrogen and out of contact with contaminating materials have shown no microscopic evidence of -a nitrogen increase; using a refractory-lined graphite crucible in the furnace under the same conditions or admitting air often resulted in the occurrence of nitride needles in the solidified melt. These results suggested that a nitrogenous compound served as a vehicle for the introduction of nitrogen and that such compound was not available when the pure gas and carbon-free refractory were used. The fusion of pure iron in pure nitrogen is perhaps a matter of theoretical interest. The author's work serves a more practical purpose when applied to steels rather than iron. Table 2 reports the absence of nitride needles in melts made under pressure of one atmosphere, although the quantity of nitrogen present would seem to exceed microscopically detectable percentages. In some recent work29 on carburized iron, nitride needles have been observed in areas analyzing as low as 0.015 per cent. nitrogen. This low percentage of nitrogen would indicate that the solubility limit is less than 0.030 per cent. for hypoeutectoid steels. There is the possibility that the areas of pearlite which exist in a hypoeutectoid steel restrict the distribution of nitrogen and limit its presence to the ferritie fields. In view of this work and the references quoted by the author, I am led to expect that the value for the solubility of nitrogen in solidified iron may approach

Jan 1, 1924

Jan 1, 1914

The term metamorphism as commonly used means any change in a rock in either form or composition, from whatever cause. By metasomatism, according to Lindgren, is meant a metamorphism that involves a change in the chemical composition of a rock by the addition or subtraction of substance. Certain types of metamorphism are due to the action of mineralizing solutions, and are closely connected with ore deposition; they form, therefore, valuable guides in the exploration for ore- deposits. Other types of metamorphism are due to regional processes, and are not connected with ore deposition. By dynamo-regional metamorphism is meant a primary alteration of rocks over large areas under conditions of pressure, flowage, and heat. This process produces schists and gneisses from either sediments or igneous rocks. It is thought that there is little migration of minerals or of elements in dynamo-regional metamorphism, and that the changes are due chiefly to recrystallization and rearrangement of original minerals in bands with their major axes oriented normal to the direction of greatest pressure. Under these conditions limestones are commonly altered to marble, and sandstones to quartzite, basic igneous rocks to greenstone or serpentine, while rocks of normal or acid com- position commonly yield the usual types of schist or gneiss. Dynamo-regional metamorphism, extending over large areas, has no connection with mineralizing processes, and is, therefore, no guide to ore deposits; while this process has certain features, such as characteristic mineral associations, in common with contact metamorphism, the results of the two processes may usually be distinguished without difficulty.

Jan 1, 1932

Jan 1, 1885

By G. J. Benard

In the 1970’s, several plants have been built and others are in the design stage which use solvent extraction for recovery of copper from acid leach solutions. Other plants are presently being built for the recovery of nickel and cobalt from laterite ores by prereduction and ammonia leaching. A review will be given on the materials of construction for these leaching and solvent extraction processes. Many plants have factors in common which permit selection with a greater degree of accuracy. Based on pilot plant corrosion data, effective use of materials of construction includes proper selection of materials, substitution of lower cost plastics for alloys, and selection of materials resistant against chloride stress corrosion cracking.

Jan 1, 1974

By P. K. Guerrero, Nathaniel Arbiter

The correlation of power consumed by a tumbling mill with the dimensions, speed, and load has been attempted by three principal methods. One of these, the torque formula, has been reviewed critically elsewhere. This approach, while analytical, disregards the individual motion and speed of the tumbling bodies and assumes that the gross geometry of the entire load is sufficient to establish the power requirement. A more general approach, using dimensional analysis, has been applied in this laboratory by the present authors, and more recently by Rose. This disregards the internal conditions within the mill entirely and in effect is an empirical procedure for correlating data. Finally, the complete analysis of tumbling mill dynamics as first made by Davis attempts to develop the power requirement from individual ball and rod paths and velocities. Although Davis' result is applicable only at a single speed for a given size and load it could be useful, since his optimum speed is at the upper limits of conventional tumbling mill practice. Where power values predicted by the Davis equation were compared with actual mill requirements, they were found too low for small mills and much too high for the largest mills. This suggested that the agreement with actual intermediate range requirements might be fortuitous, and the development of the equation was examined critically.

Jan 5, 1960

Jan 1, 1913

By James Boyd

It is obvious that mining has been influenced to a high degree by political and economic events, many of which are of such a nature that the mining industry has relatively little influence in shaping them. I cannot present too optimistic a picture for the immediate future, although I feel that from the long-range standpoint one need not be pessimistic about the future of the mining industry. The population of the United States is continuing to increase and with it has come an expanded consumption of metals on a per capita basis. With this expansion there has and will continue to come the demand for more goods and in- creased products from our mines and our fabricating plants. World War

Jan 5, 1950

DURING the past year the Committee on Coal and Coke has been collecting data concerning various points in the bituminous industry about which a large amount of misinformation circulates through the press and, in some cases, through the coal trade papers. The data presented have been compiled by various members, from the most authentic sources available, and where possible cover the period 1913-1924. They will enable comparisons to be made within the industry, and of this and other industries, and will explain some of the differences between conditions existing now and in the prewar period. CAPACITY AND OVER-DEVELOPMENT The capacity of bituminous mines is frequently stated at figures ranging between 800,000,000 to 1,400,000,000 tons per year. Table 1 shows statistics for the industry, mainly from U. S. Geological Survey sources but partly from U. S. Coal Commission reports. Column 3 gives the mine capacity with equipment and labor as of given date, as estimated from the data published by the U. S. Geological Survey. This is calculated for each State by obtaining the total man days worked as. reported by the operators (multiplying average men employed by total days worked at each mine) and dividing this figure into the total production, getting the production per man day; this figure times number of men employed times 308 (a theoretical full working year) equals estimated- full-time capacity. Two major objections are made to this method-one that the total number of men employed is used, instead of the number actually working, and the other that the number of days used only deducts Sundays and five holidays. The first objection is answered by the fact that the same number of men is used in estimating capacity as is used in actual production, and while this number is always from 12 to 20 per cent. more than are actually working, this condition exists at all times, although it is worse at times of maximum output. Few coal men will agree with the conclusion that the use of 308 days is correct, as it is practically impossible to keep any mine working full time at the same

Jan 2, 1926

D. F. HEWETT, Washington, D. C. (communication to the Secretary*).-I am not prepared to discuss the metallurgical use of manganese in the form of alloys. In connection with other work for the U. S. Geological Survey, however, I have been investigating incidentally, for about 5 years, the American as well as other sources of manganese. There are some conclusions that come out of this investigation that may interest those whose greatest interest lies in the use of the alloys. From a geological point of view, most manganese ore deposits may be regarded as concentrated masses of manganese oxides, as there are few masses of the other manganese minerals that are rich enough in manganese and low enough in silica to warrant smelting. The deposits of the Huelva district, in Spain, which are largely manganese carbonate and silicate, are exceptions to this statement. Some deposits of manganese oxides, such as those of Russia and Cuba, are bedded with ancient sediments, and although they are clearly concentrated under unique conditions, the source of the manganese cannot be determined. Probably 60 per cent. of the world's production of manganese ore, or 95 per cent., if that of Russia be excluded, is derived from the superficial parts of deposits that have undergone weathering and enrichment near the surface. In other words, the situation with the manganese ore supply is such as it would be with regard to copper, if instead of being derived largely from deep zones of deposits of deep-seated origin, such as veins, it were derived solely from the zone of secondary enrichment. Manganese oxide occurs in all rocks but is most abundant in igneous rocks, of which, according to Clarke, it forms an average of 0.10 per cent. It also forms 0.05 per cent, of the average limestone, but only traces are present in shales and sandstones. It is interesting that although many commercially important manganese deposits occur in rocks that are but slightly richer in manganese than the average, the most important deposits occur in rocks of unusual character that are much richer in manganese than the average. Thus, the most important deposits of India and Brazil overlie or occur near masses of rocks that contain excessive amounts of manganese garnet and pyroxene.

Jan 5, 1917