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5. The medal committee may invite nominations from the membership of the Institute, such nominations to be accompanied by an argument in favor of the award and details sufficient for a proper citation to be drawn. This medal has been awarded as follows: 1927—David William Brunton. 1929—John Hays Hammond. 1928—Herbert Hoover. 1930-Daniel C. Jackling. Miscellaneous Prizes Many of the Local Sections have established or administer prizes for the best paper presented within the year by any junior member. Annual Lectures Howe Memorial Lecture The Howe Memorial Lecture, in memory of Henry Marion Howe, Past President of the Institute, was authorized in April, 1923, as an annual address to be delivered by invitation under the auspices of the Institute by an individual of recognized and outstanding attainment in the science and practice of iron and steel metallurgy or metallography, chosen by the Board of Directors upon recommendation of the Iron and Steel Division. The following were the Howe lectures and lecturers for the years indicated: 1924 What is Steel? By Albert Sauveur. 1925 Austenite and Austenitic Steels. By John A. Mathews. 1926 Twenty-Eve Years of Metallography. By William Campbell. 1927 Alloy Steels. By Bradley Stoughton. 1928 Significance of the Simple Steel Analysis. By Harry D. Hibbard. 1929 Studies of Hadfield's Manganese Steel with the High-power Microscope. By John Howe Hall. 1930 The Future of the American Iron and Steel Industry. By Zay Jeffries. Institute of Metals Lecture An annual lectureship was established in 1921 by the Institute of Metals and it has come to be one of the important functions of the Annual Meeting. A number of distinguished men from this country and abroad have served in this lectureship. The roll is quoted below: 1922 Colloid Chemistry and Metallurgy. By Wider D. Bancroft. 1923 Solid Solution. By Walter Rosenhain. 1924 The Trend in the Science of Metals. By Zay Jeffries. 1925 Action of Hot Wall: a Factor of Fundamental Influence on the Rapid Corrosion of Water Tubes and Related to the Segregation in Hot Metals. By Carl Benedicks. 1926 The Relation between Metallurgy and Atomic Structure. By Paul D. Foote. 1927 Growth of Metallic Crystals. By Cecil H. Desch. 1928 Twining in Metals. By C. H. Mathewson. 1929 The Passivity of Metals, and Its Relation to Problems of Corrosion. By Ulick R. Evans. 1930 Hard Metal Carbides and Cemented Tungsten Carbide. By 8. L. Hopt.

Jan 1, 1930

By Frank M. Howell, Claude E. Schmidt

To counteract the spiralling costs of labor and materials against the fixed sale of its product, namely, gold at $35 per oz, Homestake Mining Co. has revised the milling flowsheet once and effected increases in the daily milling rate twice in the past 12 years. During this period the mining department has been able to hold production costs steady by increased productivity through technical improvements and utilization of the most modern mining by CLAUDE E. SCHMIDT and FRANK M. HOWELL, JR. 46-MINING ENGINEERING, APRIL 1963 equipment. The flowsheet alteration occurred during 1951-1953 when the two crushing plants at the shaft head frames were converted to a three-stage crushing system with the third stage closed circuited to produce a minus 5/8-in. product as rod mill feed.

Jan 4, 1963

By Clifton W. Livingston

So many factors influence blasting results that theories and rules are usually dismissed as impractical; the practice prevailing today is arrived at by cut and try. Usually the first step is to experiment with drillhole patterns and spacing until an arrangement is found that gives best results. The next step is to experiment with different types of explosives and sequences of blasting until the most satisfactory degree of fragmentation is achieved and until no further reduction in cost is immediately apparent. Improved fragmentation is generally attributed to the type of powder used, the sequence in which the holes are blasted, or the use of millisecond delays. Various types of drill rounds have been evolved in tunneling operations, underground development headings, and stoping, and various patterns of blasting in open pit mines and quarries. These practices usually are carried from mine to mine or from district to district, and great skill is exercised by those experienced in the art of blasting.

Jan 1, 1960

By Thomas F. Evans

This study shows that statistics on the rate of coal dumping can measure the effectiveness of freeze conditioning agents. The use of appropriately indexed dumping intervals or interval logrithms provides a more sensitive indication of unloading problems than does a simple calculation of average loading time because of the abnormal form of the distribution of dumping intervals. The paper presents information that indicates suitably applied coal freeze conditioning agents are effective in reducing coal handling problems attributable to frozen coal. Graphs and figures show that the severity of coal freezing potential due to subfreezing temperatures is proportional to the exposure time and average departure of the temperature from the freezing point.

Jan 1, 1982

By Catherine T. Aimone

Specimens of copper-bearing quartz monzonite were subjected to a plane shock wave simulating high compressional stresses in the proximity of a borehole wall. Fragmentation was studied as a function of stress levels between 1.6 GPa (23 x 104 psi) and 7.3 GPa(105.8x104 psi) and pulse durations ranging from 1.1 µs to 6.9 us. Both explosive pressure and pulse duration were shown to have a strong effect on particle size distribution. While the effect of pressure is well recognized, the effect of pulse duration indicates that ultimate fragmentation increases with the time of application of a plane wave pulse. At high pulse durations, degree of fragmentation is more sensitive to changes in pressure than at low pulse durations.

Jan 1, 1984

W. P. PUTNAM,. Detroit, Mich.-There is one company that is heating these tubes in an upright position by passing electrical energy directly through the tube itself. The lower connection is attached to an indicator, which shows the point at which the steel passes through the critical range At that point the clamps are released and the tube is dropped into a well of oil. This method simplifies the heat treatment of tubes in long lengths. H. J. FRENCH.-I am not entirely familiar with. the method outlined, but it appears to have one serious disadvantage; that is, the length of tubing that is directly connected with the electrical contacts is wasted and must be cut off due to either heavy oxidation or burning. That is a serious difficulty, if true in all cases, and cannot be overcome, inas-much as it is very difficult to draw long tubes of thin wall. Having once obtained a lot of tubes, to cut, say 14 ft. in length, there is often little excess metal available to discard. Am I correct concerning the burning or heavy oxidation of the metal where it comes in contact with the tube.

Jan 12, 1919

By A. M. Gaudin

MANY studies of comminution have been made to ascertain the size distribution of the product and to evaluate the work of comminution in the light of the size distributions of the feed and product. Up to now, these studies have been essentially statistical in character, that is, a certain lot of feed was subjected to comminution in some specified way, and the aggregate product was fractionated into sizes, thereby losing all knowledge of individual relationship of feed to product pieces. Radioactive tracers offer a means to do something in this respect which could not be done before, namely, to follow the rupturing of some particular piece in its normal environment of other pieces. That is, it permits going beyond the usual statistical limitations of size distribution studies to what may be termed a personalized or individualized study. The purpose of this paper is to present some preliminary experiments conducted with this tool.

Jan 11, 1951

Upon nomination of the President, _the following Committee on Membership was appointed: Karl Eilers, Chairman, Arthur. S. Dwight, Lewis W. Francis, Louis D. Huntoon, Arthur L. Walker. The following resolution was then unanimously passed: WHEREAS, the integrity and life of this nation is dependent upon its ability to successfully defend itself against foreign aggression and attack, and WHEREAS, it is necessary that the nation he properly prepared to the end that our untrained patriotic volunteers he not uselessly slaughtered and our country disgraced and defeated, be it therefore RESOLVED: That the Board of Directors of the American Institute of Mining Engineers believe that compulsory universal military training should be at once instituted and that adequate, complete and immediate preparedness, should he provided. BE IT FURTHER RESOLVED: That, we believe that thorough and complete preparedness in the army, the navy and the industries of the country is vital; anything less is unsatisfactory and inefficient and may result in disaster to the nation.

Jan 5, 1917

SAMUEL L. HOYT,* Minneapolis, Minn. -I was privileged to see the apparatus used by Mr. Scott, which is quite unique. It is, as the author says, a modification of the apparatus designed by Dr. Rosenhain, but it is evidently quite an; improvement. The author is to be congratulated on the fact that lie has given us, with his apparatus, a quantitative thermal analysis of these critical points. I notice the author refers to Ac3, Ac2, and Ac1. His designation of the Ac2 point is all right, but naturally in a steel with as much carbon as this, which would mean a hypereutectic steel, the other point might better be considered as an Ac, point with possibly another point above the Ac, point. Another important point brought out is the fact that, in Fig. 3, the lines representing the Ar1, transformation and the Ac,1_3 transformation do not intersect at the zero rate curve,

Jan 5, 1919

By Lennart Bergstedt, Olov Fägremo

Boliden Metall Aktiebolag, the prime base metal mining company of Sweden, treats some 10-10.9 t/y (11-12 stpy) of sulphide ore in nine concentrators. During the years considerable effort has been devoted to the development of all phases of the technology of ore prospecting, mining, milling, smelting and refining. This has been necessary due to the complex and low grade ores. The autogenous grinding technique was first studied within the company as early as 1945. Basic test work commenced during the early fifties, whereby the merits of pebble grinding could be evaluated.

Jan 2, 1978

By T. M. Anderson

Open pit mining at Inspiration began in 1947 after 32 years of underground mining. Two separate pits are included in the operations: the Thornton pit, which measures approximately 2500 x 2000 ft, and the Live Oak pit, which is 1500 x 3000 ft. The geographic centers of the two pits are approximately 4000 ft apart, and at the closest point, the two slopes are only 500 ft apart. Today, much of the open pit mining is being carried out in areas which were broken by earlier underground block caving operations; less than 50% of the total material moved has required drilling and blasting. In the solid or virgin areas, the, material ranges only from soft to medium hardness, thus simplifying drilling, blasting and loading operations. As a result, most mining costs and problems have been centered around truck haulage, truck maintenance and the ever-increasing length of the grade haul.

Jan 3, 1963

By H. C. Meister

The zinc-smelting industry of the United States has grown very rapidly in recent years and bids fair to outrival that of all other countries in the future. On account of the geographical situation of the chief ore-supplies, the industry may be divided into two main groups, the eastern and the western. The eastern and older group includes the works of Penn-

Jan 1, 1905

I strongly endorse Mr. Jackson's (Inland Steel Company) oral comment on the authors' paper that, as blast furnace slag is removed from the BOF charge, lime solution may be retarded. After two or three pourings, the blast furnace slag will contain some iron oxide and considerable manganese oxide, and it is hot and possibly still liquid. A few thousand pounds of this slag will speed up the slag development rate considerably and could be considered a good auxiliary flux. Although the removal of blast furnace slag from the BOF charge lowers the total sulfur load by 40 to 50%, we must have a good, quick slag development in the BOF to bring .030 to .035% sulfur hot metal to .020%, a requirement on a high percentage of our steels today. In discussions at off-the-record meetings and one not published at last year's annual meeting as well as discussions with many operators over the past 1-1/2 years, I predicted that the removal of blast furnace slag could slow down lime dissolution and that, if a shop had dissolution problems before, the problem could be quite serious.

Jan 1, 1972

IN recognition of thirty-one years' service as professor of mining in McGill University the friends of Dr. Porter gave him a complimentary dinner at Montreal, on Jan. 24. The affair was appropriately held under the auspices of the Montreal Branch of the Canadian Insti-tute of Mining and Metallurgy, George C. Riley presid-ing, and was made the occasion of presentation to him of a Canadian landscape painted by Maurice Cullen, and of a silver plate to Mrs. Porter. Among those speaking were Messrs. George E. Cole, F. D. Adams, Sir Arthur Currie, W. C. McBride, and J. G. Ross. Mr. Cole spoke of the large part Professor, Porter had played in the development of mining in Canada through training the men who had become the leaders in the work. More than 200 mining engineers graduated from the University during Dr. Porter's tenure of office and while not all of them had continued to practise their profession, as a body they had had an immense influence.

Jan 2, 1928

Members whose deaths were reported from Mar. 5, 1919, to Apr. 5, 1920. Elected Died 1895 ANDERSON, ROBERT HAY 1920 1916 ATWATER, M. W 1919 1905 BARD, D. C 1920 1893 BECKER, GEORGE F 1919 1914 BIGELOW, BRAXTON 1917 1917 BLACK, HERBERT F 1919 1911 BOWLER, ROBERT P 1919 1902 BROWN, ARTHUR H 1919 1913 BURNHAM, WILLIAM 1918 1905 Carnegie, Andrew 1919 1900 CARPENTER ROLLA C 1919 1908 CONNER H. MCKEAN 1919 1883 COOK, ROBERT A 1919 1903 COOPER, JOHN 1919 1875 CROXTON, SAMUEL W 1919 1889 DICKMAN, R. N 1919 1893 DUFOURCQ, EDWARD L 1919 1917 FAY, CHARLES H 1918 1875 FOHR, FRANZ 1919 1879 FRICK, H. C 1919 1880 GAYLEY, JAMES 1920 1917 GARVIN, JOHN C 1920 1915 GIBBS, CHARLES H 1919 1917 GODBE, RALPH T - 1918 GREGORY, A. E 1919 1917 HAMILTON, A. McL 1918 1914 HEISE, HENRY C - 1913 HINCKLEY, E. R 1918 1884 JENNINGS, HENNEN 1920 1895 JOHNSON, J. E., JR 1919 1895 KANN, MEYER M 1919 1895 KAYSER, H. W. F 1919 1918 KENNEDY, DANIEL J 1903 KING, PAUL S 1919 1901 LANGTON, JOHN 1920

Jan 1, 1923

R. B. BrinSmade, Ixmiquilpan, Hgo., Mexico (written discussion*).—While agreeing with Mr. Gibson that his net-profit tax is the fairest and best for mines, I believe that the tax he describes can be more accurately defined by another name. In accounting, net profits are usually considered to be the residual of the gross income after operating expenses and the annual charge for upkeep of plant have been deducted. Even the necessary interest on bonds or mortgages should not be subtracted in this calculation, for this interest represents merely that fixed portion of the net profits going as a return to that fraction of the total property value owned by the bondholders. Applying this method of calculation to the gross income of a mining property, we should onIy deduct operation expenses and upkeep of plant to get the net profits on its whole property value. So Mr. Gibson in deducting a further sum, to cover the interest and amortization of the capital expended in mine development and equipment, really arrives at something quite differen't from net profits; which can properly only be defined as the annual value of the mineral in the ground, or the royalty value in miners' parlance. From one viewpoint, Mr. Gibson's first principle, which assesses taxes, "proportionate to the benefits received by the person or property taxed," is identical with his third principle wbich assesses "with reference to the extent and value of the natural resources enjoyed." With one exception, everything of use around a mine represents a cash expenditure, or its equivalent in human labor, and state action has not added an iota to its value. The one exception is what makes the enterprise possible and it includes the mineral deposits and their associated surface; water and other landed rights. These natural resources are origin2!1y the gift of tile people acting through their agent, the state, and it is evident that a tax laid on whatever profits may arise from their enjoyment will be exactly "proportionate to the benefits received by the person or property taxed." Mr. Gibson is mistaken in his belief that the general property tax of the United States has the same incidence as his system of taxing profits, because the general property tax falls not only on land1 value—as does

Jan 1, 1920

By J. N. Houser

THE industrial relations between the Tennessee Copper Co. and its employees have developed a number of interesting things and have been most, profitable to the employees and to the company. It is noteworthy that considerable has been done without a formal organization of any kind built up through the efforts of the company. From time to time there have been discussions regarding the advisability of a formal organization and the decision has always been in favor of the present method. In the year 1919, the company was dealing with its employees through union committees and, after an understanding was reached, satisfactory results began to be obtained, but as time went on the committees did not function and it came to a question of how to reach the men. For the past two years, about once a month, but at no stated time, there has been a meeting with a committee of employees consisting of 40 or 50 men out of 700. This committee is secured by notify-ing the locals. In addition, the Service Department notifies a number of men not represented in the union, so as to have a large representative committee. The meetings are on company time and the men are rotated, so that in time every employee attends , at least one meeting. All department heads and a number of foremen also are present. The operating plans and policy of the company are set out at the meetings and the market outlook for products is discussed. Explana-tions are also given of anything that has come up since the last meeting which affects the employees, and an effort is made to inform them of what will probably happen in the next month or two. Once a week there is a meeting of department heads with the manager, for discussion of all operations as a whole and such depart-mental details as seem advisable. When the depression started, it was necessary to curtail operations and the reasons were carefully explained; before the men were laid off, the employees as a whole were advised of the coming layoffs through these meetings. They were also advised generally who would be retained and given an opportunity to express their agreement or their. disapproval. In fact, an effort was and is being made to keep the employees advised in advance of matters affecting them and to give them full opportunity to express themselves.

Jan 12, 1922

By Abderrafih Guessous

INTRODUCTION Morocco is an important lead-zinc producing country: 120,000 tons of lead concentrates were produced in 1968. Zinc ore production is less, 67,000 tons of concentrates in 1968. Most of the present production comes from three districts (fig.1) (i) Touissit-Bou Beker district, in the eastern part of the country, close to the border with Algeria. (ii) Aouli-Mibladen district, in the central part of the country. (iii) Aouam district, about $0 miles south of Meknes. In the first district lead and zinc are always found together. The two other districts produce mainly lead. This paper will be limited to a short description of geology and mining methods in the three aforementioned districts. More detailed geological informations can be found in the symposium on lead-zinc deposits in Africa (1).

Jan 1, 1970

ARSENIC and orpiment are two mineral substances of a similar kind, and they are by nature pure, without admixture of other species. In regard to their apparent qualities we shall say that their composition is scorched, well-purified earth; and because of a certain subtlety and easy digestion they penetrate very easily into fused metals, indeed they act in such a way that they corrupt and convert almost into another nature any metal with which they find themselves. Orpiment and arsenic act in almost the same way as do tin and mercury. With these the fraudulent alchemists blanch copper, brass, and even lead to the whiteness of silver. According to the physicians they are in fourth part hot and dry. They are also corrosive because of certain powers; indeed, they are a most powerful poison to the life of all things. Arsenic is found in white and citrine colors. Orpiment seems to be a separate thing, although both are formed in the same ore and both are in lamellae or scales. These lamellae or folds are thinner than paper, in fact

Jan 1, 1942

By H. A. Bauman, T. S. Spicer, C. C. Wright

Experimental data are presented showing the influence of size consist and firing rate upon the performance of bituminous coal-fired, single-retort, industrial underfeed stokers. Size segregation, degradation, and distributor data are also included. The conclusion is reached that size consist of the fuel as fired, is a critical factor in its performance on this class of equipment.

Jan 2, 1950