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By W. J. C. Venter

The use of activated carbon to improve the selectivity in the separation of base metal minerals from bulk concentrates played an important role in the development of separation techniques employed at Tsumeb Corp.'s Tsumeb and Kombat mines. The Kombat mill fiowsheet and metallurgical data are given with particular reference made to the separation techniques using activated carbon. The mine's historical background, geology, and mining methods are described briefly.

Jan 1, 1974

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York L. W. FRANCIS, Chairman, WILLARD S. MORSE, Vice-Chairman. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. P. A. MOSMAN, Treasurer. LOUIS D. HUNTOON. WILLIAM A. POMEROY. Boston HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. AUGUSTUS H. EUSTIS, Secretary-Treasurer, 131 State St., Boston, Mass. ROBERT H. RICHARDS,. ALBERT SAUVEUR. Columbia F. A.. THOMSON, Chairman. GEORGE W. RODDEWIG, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. R. S. McCAFFERY, S. H. RICHARDSON.

Jan 12, 1914

By F. W. Denton

Much has been written about the possibilities of the Vermilion and Mesabi ranges of northern Minnesota as producers of large quantities of high-grade iron-ore. The Mesabi range in particular has attracted considerable attention on account of the proximity of the ore-deposits to the surface, which has been as-

Jan 1, 1898

By J. E. Crawshaw, Francis B. Foley

In the first report1 disks of steel of known composition and history were exposed, under carefully prescribed conditions, to impacts of explosion products resulting from the explosion of 50-gm. charges of explosives having well-determined rates of detonation, or to impacts of a weight of known mass, falling through measured distances. There were available at the Bureau of Mines Experiment Station five explosives, having rates of detonation of 5716, 4470, 3190, 2296, and 1523 meters per second. It being desired to continue this exposure downward, and no explosives with a lesser rate of detonation being at hand, resort was had to the impact of a falling weight, the differences in the velocity of impact being attained by varying the height from which the weight was allowed to fall. It was expected by this means to demonstrate experimentally that the development of Neumann bands was determined by the suddenness of the deformation of the metal in which they were produced. But while progressive deformations were obtained with the explosive charges, the falling-weight method failed because the tup was progressively deformed, also the disks were so flattened as to be unfit for metallographic examination. A return, therefore, has been made to the use of explosives as the source of energy, an air-gap being interposed between the charge of explosive and the disk, as the effect diminishes as the function of the distance between the charge and the object on which the products of its explosion, or the shock wave from its detonation, impinge. The details of the arrangement of the tests by the air-gap method were the same as those described by Foley and Howell,2 except that after the system had been set up and the desired apparent specific gravity for the explosive attained by tamping it, the small lead block, with the steel disk adhering

Jan 1, 1926

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period May 10, 1916 to June 10, 1916: G. Aertsen, Philadelphia, Pa. Hennen Jennings, Washington, D. C. Frederick C. Alsdorf, Wickenburg, Ariz. H. M. LaFollette, LaFollette, Tenn. A. H. Anderson, Worcester, Mass. E. T. Lednum, Chicago, Ill. J. H. Batcheller, Mattapoisett, Mass. Francis Church Lincoln, Reno, Nev. Arthur B. Clark, Sheridan, Mont. H. Mortimer-Lamb, Montreal, Canada. J. Murray Clark, Toronto, Canada. Andrew W. Newberry, San Francisco, Cal. J. H. Collier, Oakland, Cal. C. E. Pettibone, Cleveland, 0. H. S. Emlaw, Spring Lake, Mich. Heinrich Ries, Ithaca, N. Y. E. L. Estabrook, Platteville, Wis. C. S. Robinson, Youngstown, 0. James W. Hambleton, El Paso, Tex. - M. K. Rodgers, Basin, Mont. James Henderson, London, England. E. J. Rossbach, St. Louis, Mo. G. P. Hulst, East Chicago, Ind. J. B. Tyrrell, Toronto, Canada. William F. Jahn, Riebeling, Mont. G. B. Waterhouse, Buffalo, N. Y.

Jan 7, 1916

By R. M. Board

This paper will focus on measurement and control of four main aspects of crushing, namely horsepower, bowl level, mantle position and feed rate, and will discuss related sensors and control techniques, some of them designed specifically for crusher control, that have proven successful and reliable in many installations.

Jan 1, 1982

By S. S. Clarke, Douglas C. Brockie

Longhole underground drilling has been carried on in the Tri-State area at various times over the past 35 years or more. W. F. Netzeband reported on this topic in 1926 and in 1930. More recently it has been found that in certain areas of the Picher field, Oklahoma, and under certain conditions, the jackleg or jumbo-mounted drifters can be used more economically and to greater advantage than surface churn drillholes for prospecting. To understand better the problems involved in Eagle-Picher's longhole prospecting program it would be helpful to cover the geologic criteria affecting it. Much has been written about the geology of the Picher field. A more complete description than that given here can be found in a recent paper by J. P. Lyden.

Jan 1, 1956

By Henry M. Howe

Jan 1, 1908

By Joseph E. Pogue

The past year in the petroleum industry was one of overproduction, rising inventories, low prices, and meagre to vanishing profits. This outcome was the result of a long period of intensive and uncompensated effort on the part of both financial and industrial interests, to stimulate supply on the theory that the primary problem facing the petroleum industry was the development of an adequate reserve of raw material to protect a large and ever-growing investment. The stimulus was applied in various forms and through diverse channels: capital had long flowed into the industry in excessive amounts under the attraction of large expected profits; the price level for crude petroleum had persistently been influenced by speculative considerations, with the result that prices declined slowly in periods of flush production and were quick to advance in anticipation of statistical improvement, thus maintaining a superfluous degree of stimulus on wildcatting and on drilling; speculation in inventories had led to the unsound, or at least unusual, business practice of accumulating huge stocks of oil; and, above all, the industry had directed the potent force of technology to the expansion of supply and achieved radical results in accelerating oil discovery, speeding up the rate of oil extraction, and enlarging the recovery of gasoline and lubricating oils from the raw material. In short, the economic conditions of 1927 were exactly those to which the objectively driven enterprise of the petroleum industry had long been directed; and the undesirable financial consequences arising therefrom reflected no lack of success in what had been set out to be achieved, but rather the failure to have established concurrently the necessary means of economic control to prevent the immediate conversion of reserves into current supply, and likewise the oversight in neglecting to apply the technological force to the enlargement and diversification of the market for petroleum products. Perhaps, when viewed in its longer perspective, 1927 will stand out as the turning point in the economic policy of the petroleum industry, when the technique of rationalizing production made its initial claim for recognition.

Jan 1, 1928

By Eckley B. Coxe

Having been appointed, on February 19th, 1890, a member of the Commission created by the Legislature of Pennsylvania for the purpose of investigating the " Waste of Coal Mining, with the View to the Utilizing of the Waste" (waste in this case referring specially to the small sizes of anthracite heretofore thrown away), my attention was naturally directed to the mash economical method of burning these small sizes.* Although I had been Familiar with the burning of anthracite for • many years, I found when I came to study the matter carefully that I was far from thoroughly understanding it, particularly with reference to the hurning of the smaller sizes, and that the literature of the subject, which was not very extensive, had more of a tendency to confuse than to enlighten me. I began therefore to investigate the subject so as to arrive if possible at some definite principles applicable to the question. With the aid of my assistant, Mr. John R. Wagner, I began at Drifton a series of experiments upon the burning of small anthracites. We first erected a small furnace with a grate 3 feet long and 2 feet wide, with which we experimented about two months. From the information thus acquired, we designed and built another furnace of about the same size, which gave us facilities for extending our investigations still further. After experimenting several months with the second furnace, we built a third one, which was much larger, having a grate area of about 68 square feet, which was exactly the size of the grate used in the boiler-plants of' Coxe Bros. &

Jan 1, 1894

By R. S. Hooper

In attempting to describe recent mining developments at the Bunker Hill mine, it may be well to recall first the old days of hand mining when holes were laboriously drilled by hand to a maximum depth of three feet, and were shot one or two at a time, in order that the miner could take advantage of every slip, crack or bedding plane, and so save as much drilling as possible. Broken muck, of course, was loaded by hand shoveling into wheelbarrows or small cars, and heading advances or stope tonnages were governed by the number of men that could find room to work in any given place. The first big improvement over these old methods was the introduction of the reciprocating type of air-powered rock drill. This innovation, crude as it was, enabled the miners to set up a machine and drill a complete round of holes in one shift; but broken muck was still loaded by hand, and the size and rate of advance in headings were limited by time required to remove the broken rock. The next improvement of consequence was the appearance of the hammer-type rock drill, which greatly increased drilling speed over the reciprocating type, and made possible the completion of a full cycle in one shift, by the use of crossbars in headings, and permitted drilling and mucking to be carried on at the same time. Rock drills continued to improve as time passed, and finally the smaller and more efficient mucking machines appeared on the scene, and it became possible to muck out a round of broken rock and have a clean setup for one or more drill columns and machines. A complete cycle of mucking, drilling, and blasting was completed in one shift with an average advance of five feet. These conditions prevailed for several years, but as the mine grew deeper, the distances to transport the workers grew longer, and this fact together with the shortening of the working day, soon presented the problem of attempting to complete a cycle of operations in a shift of only six hours at the working faces. Anticipating this condition, the operating heads at the Bunker Hill had started an intensive study of more and better mechanization, and over a period of comparatively few years have adopted and placed in service methods and machines that make it possible for a three-man crew to consistently advance headings seven by nine feet in cross section, at the rate of eight feet, and more, per shift, doing all the mucking, switching, drilling and loading. These improvements consist of the following major items: I. The development of a light, flexible, easily transported jumbo equipped with pneumatic columns (Fig I), that has decreased the "setting up" and "tearing down" time an average of 11/2 hr per shift, Or 25 PCt of the available working time. These jumbos were developed at the Bunker Hill mine by members of the staff and consist of two pneumatic columns attached to a suitable carriage. They fold

Jan 1, 1949

By Zay Jeffries

Page Introduction............................. 474 Nature of Experiments ........................ 476 Materials Used in Experiments..................... 476 Description of Samples........................ 476 Details of Tests and Apparatus .................... 486 Determination of Elongation...................... 488 Determination of Reduction of Area .................. 488 Results of Tests........................... 489 Quantity and Arrangement of Amorphous Phase............. 497 Properties of Amorphous and Crystalline Phases............. 501 Intercrystalline Fracture........................ 530 Trans-crystalline Fracture....................... 531 Rupture ............................... 535 Explanation of Beilby's Results..................... 536 Mechanical Properties of Copper Wires................. 537 Mechanical Properties of Tungsten Wires................ 542 Mechanical Properties of Iron Wire................... 546 Effect of Diameter of Wire on Mechanical Properties........... 554 General Considerations on Properties of Metals at Very Low Temperatures .. 556 General Considerations on Physical Properties of Complex Alloys...... 557 Summary.............................. 559 Discussion.............................. 562 Introduction DuRing the period 1914 to 1916. the writer observed many times that tungsten wire could be drawn hot until it became brittle but on cooling to room temperature it became ductile again. In searching the literature for parallel cases. it was found that Beilbyl had produced hard-drawn wires of gold. silver. and copper that showed less than 1 per cent.

Jan 1, 1919

By Lyall Zickrick, R. S. Dean, F. C. Nix

The first attempt to establish an equilibrium diagram of the lead-antimony series was made by Roland-Gosselinl in 1896. This investigation classified the system as a purely eutectiferous one, with the eutectic at 12.5 per cent. antimony and 228" C. In the next year, Stead2 placed the eutectic temperature at 247' C. The error in temperature made by Roland-Gosselin, however, has been perpetuated in the literature with a remarkable degree of persistency; this value was accepted by Campbell (1902), and Ewen (1910),3 and will be found in the last edition of Desch's3 Metallography (1922). Gonterman's investigation, made in 1907, was the most complete one available at the time .the present investigation was started. He concluded4 that the system was a simple eutectiferous one and placed the eutectic at 13 per cent. antimony and 247° C. Other investigations by Tammann (1907),5 Garbow (1909),6 Rudolfi (1910),7 Loebe (1911),8 and Leroux (1913)9 added little, if anything, to Gonterman's diagram. A number of investigations have been made of physical properties of the alloys. The electrical conductivity of the series was studied by Matthiessen (1860)10 and by A. W. Smith (1921);11 the thermoforce by Rudolfi (1910),12 and Pelabon (1923) ;13 the specific heat by Durrer

Jan 1, 1926

By Milton Ohring, Stephen M. Edelglass

THE recently determined coefficients for diffusion of very dilute impurities in aluminum are shown in Table I. Of these data the activation energies for Ag110, cu54, Mn54 and zn85 are clustered about the value of self-diffusion in aluminum; for the remaining

Jan 1, 1970

By AIME AIME

APPARENTLY unperturbed by any misgiving as to ill luck connected with the mystic number thirteen -for there were exactly that number of Directors on deck-the Board held two sessions on Tuesday, Feb. 21. , . Between the executive session at 5:15 p. m. and the general session at 8:30 p. m., 28 Section and Division delegates were wests of the Directors at dinner. Committee chair- " men and past officers brought the attendance to 75. Messrs. McAuliffe, Merica, Mudd and Tally had expressed their intention to be at the Directors' meeting, but each was prevented unavoidably at the last minute. At the executive session of the Board, J. V. W. Reynders was unanimously chosen to fill the unexpired term of Dr. Becket as Director: and Eugene McAuliffe in like " manner was selected to become Vice-president to fill the vacancy created hy Dr. Becket's assumption of the Presidency. Upon nomination of President Becket the following Executive Committee was appointed: Frederick M. Becket, chairman; Howard N. Eavenson, H. A. Guess, J. V. W. Reynders and William Wraith; and the Finance Committee was appointed as follows: Henry Krumb, chairman; Paul D. Merica and H. G. Moulton. Karl Eilers was reelected Treasurer and A. B. Parsons was re- elected Secretary to serve for the ensuing year, whereupon the executive session was adjourned.

Jan 1, 1933

By I. Milton LeBaron

Operation of the phosphate flotation plant at the Peace valley mine of the International Minerals and Chemical Corporation, Florida, began in the summer of 1942. Since that time several changes have been made in the flowsheet, with resultant increases in metallurgical results. Three flowsheets, together with the comparative plant results, are given in this paper, together with a discussion of the desliming circuit used for preliminary washing of the flotation feed. Fig. I lists the essential units in the original flowsheet at the Peace Valley plant. The figures for tonnage and grade are average for a period of two months. Mineral Separation Airflow cells are used for both the fatty acid and the amine float. Three immediate difficulties presented themselves in the use of this flow sheet: I. Floating a maximum amount of phosphate in the rougher section to give good recovery sent a low-grade concentrate to the silica float, resulting in high costs for amine reagent in that section.

Jan 1, 1947

PENNSYLVANIA ANTHRACITE LOCAL SECTION On Saturday evening, Jan. 31, 1914, about 40 members of the Institute met at the Hotel Sterling, Wilkes Barre, Pa., for the purpose of discussing plans for the formation of a local section in the Pennsylvania anthracite region. President Rand; Prof. Joseph W. Richards, of the Board of Directors; Dr. H. M. Chance, Chairman of the Committee on Coal and Coke, and Secretary Stoughton were among the guests present. R. V. Norris acted as Master of Ceremonies, and the arrangements were all made in advance by a Committee under the leadership of Charles Enzian, to whom an enthusiastic vote of thanks was accorded at the dinner. An address was made by President Rand, followed by .Professor Richards, who outlined the procedure necessary for the formation of a Local Section. Addresses were then made by W. J. Richards, F. W. Chase,. C. F. Huber, R. J. Foster, F. A. Hill, H. M. Chance, Bradley Stoughton, and others, after which a rising vote was taken, and it was unanimously decided to petition the Board of. Directors for the establishment of the Pennsylvania -Anthracite Local Section. More than the required number of members then signed -the petition, and President Rand announced the appointment of a Committee to organize the Section and arrange for a meeting in accordance with their By-Laws, consisting of R. V. Norris, W. J. Richards, R. J. Foster, Edwin Ludlow, C. F. Huber, Charles Enzian, Douglas Bunting, F. A. Hill, and J. M. Humphrey.

Jan 2, 1914

By G. Herget

Finite-element analysis of slopes and a field trial of a slope support system have shown that a considerable potential for excavation reduction exists if slopes are designed with variable slope angles with depth, and if artificial support systems are made an integral part of the slope design. A cost analysis has shown that the savings for a straight 500 ft. high slope with artificial support can amount up to $900 per foot of horizontal pit extension. Horizontal stresses and displacements can be overestimated by up to 100% by employing a two-dimensional finite-element analysis instead of a three-dimensional one. Stress magnitudes differ considerably when comparing results from slope models subjected to a gravity stress field with slope models subjected to high horizontal stresses. Because the latter case appears to be predominant for open pits, slope stability analyses have to be adjusted accordingly. A field trial measuring peak accelerations and displacements has shown that the use of pre- shearing for termination bench blasts, in cases of already heavily fractured ground, can be more detrimental than beneficial.

Jan 1, 1972

By I. Milton LeBaron

Operation of the phosphate flotation plant at the Peace valley mine of the International Minerals and Chemical Corporation, Florida, began in the summer of 1942. Since that time several changes have been made in the flowsheet, with resultant increases in metallurgical results. Three flowsheets, together with the comparative plant results, are given in this paper, together with a discussion of the desliming circuit used for preliminary washing of the flotation feed. Fig. I lists the essential units in the original flowsheet at the Peace Valley plant. The figures for tonnage and grade are average for a period of two months. Mineral Separation Airflow cells are used for both the fatty acid and the amine float. Three immediate difficulties presented themselves in the use of this flow sheet: I. Floating a maximum amount of phosphate in the rougher section to give good recovery sent a low-grade concentrate to the silica float, resulting in high costs for amine reagent in that section.

Jan 1, 1947

By M. Semchyshen, A. P. Coldren, W. G. Scholz

A survey of the Fe-Mo-B system was made to determine the extent to which boron might affect the microstructure and strength properties of iron-rich Fe-Mo alloys. Seventeen vacuum-induc tion melted ingots were prepared with approximate mo-lybednum contents 01 2, 4, 9, and 19 wt pct and approximate boron contents of 5, 14,50, and 630 ppm by weight. Phases extracted from annealed specimens and identified by X-ray diffraction analysis included E Fe3MO2, Mo2FeB2, and an oxide hazling a diffraction pattern practically identical to that of MnFez04. Three types of alloy strengthening were observed: a) Fe-2 pct Mo-B alloys were hardenable by a bainitic-type transformtion of austenite to ferrile; b) Fe-4 pct Mo-B alloys were hardened by the solid-solution mechanism; and C) Fe-9 pct Mo-B and Fe-19 pct Mo-B alloys were hardened by precipitation of the E Fe3Moz phase. Boron was observed to have a very strong hardening effect in the Fe-2 pct Mo alloys and a mild strengthening effect on the 1200°F properties of the Fe-4 pct Mo alloys. In the Fe-9 pct Mo alloys there was no consistent effect of boron on strength at either room temperature or 1200° F. The Fe-19 pct Mo alloys were so brittle that meaningful tensile or creep-rupture data could not he obtained. No dispersion hardening from borides was recognized in any of the alloys. THE high-temperature properties of iron-rich Fe-Mo alloys were studied by Reiter and Hibbard.' They found that the strength of the alloys increased markedly as the molybdenum content was raised from 0 to 15.9 pct by weight. The authors explained the various degrees of strengthening in terms of a) solid-solution strengthening, b) strengthening from a martensitic-type transformation, and C) precipitation strengthening. The objective of the present investigation was to conduct a survey of the iron-rich portion of the Fe-Mo-B system to determine whether the beneficial effects of molybdenum on the strength of iron can be enhanced by the presence of boron. It was thought that perhaps fine dispersions of molybdenum- rich borides would be found which could improve the high-temperature strength of ferritic alloys beyond the strengths attainable by molybdenum additions alone. Also, it was considered worthwhile to study the effects of boron in alloys which are essentially free of carbon. Most, if not all, of our present knowledge about boron in high-temperature alloys pertains to alloys containing carbon and carbides. EXPERIMENTAL PROCEDURES Alloy Preparation. Seventeen 8-lb ingots were prepared from electrolytic Plastiron, unalloyed molybdenum chips, and boron powder by a vacuum-induction melting procedure employing hydrogen as the main deoxidizer. The alloys were melted in alumina crucibles using 35-lb melts, with each melt being split four ways to achieve varying boron contents within four Fe-Mo base compositions. The results of chemical analyses conducted on chips machined from the chilled ends of the ingots are presented in Table I. The boron analyses were performed by a spectrographic method utilizing primary standards prepared from boric acid. They indicated that in ingots to which no boron was

Jan 1, 1964