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By Frederick Forscher

Frederick Forscher (Nuclear Materials and Equipment Gorp.)—It is gratifying to see another series of experimental results that essentially reconfirms our reported observations of "Strain-Induced Hydrogen Embrittlement in Zirconium" (F. Forscher: AIME Trans., 1956, vol. 206, p. 536, noted as Ref. 3 of paper). However, several important considerations may have been overlooked, or—at least—have not been specifically pointed out. It is the purpose of this discussion to present some of these considerations. The statement is made that "the equilibrium concentration of hydrogen in solution at 20°C in zirconium is approximately 10 ppm; i.e., no zirconium hydride precipitates are formed at or below this hydrogen content." This is perhaps the case in the unstressed condition. In the presence of triaxial (plastic) strain however, even as little as 1.4 ppm H2 (Forscher's Figs. 6 and 11) will cause porosity near fracture in 20°C tests. The necked-down region that develops during a tensile test provides the triaxiality necessary for these pores to open. Both Beevers' and Forscher's micrographs show that porosity is concentrated in the necked region. So-called "pure zirconium" containing about 10 ppm H2 also shows pronounced porosity near fracture (Beevers' Fig. 3). Since it is generally agreed that such porosity is

Jan 1, 1965

By H. R. Hendricks

The ore of the Iron King mine, being very hard and having a very fine crystalline structure, presents many problems in milling that are not present in ordinary lead-zinc ores. This very fine crystallization causes much interlocking of minerals and is most prevalent between the gold and pyrite and the sphalerite and pyrite. The recovery of gold is extremely important in the economic value of the ore and therefore constitutes a large part of the metallurgical problem to be solved. All of the gold is free but it has not been observed in any of the mill products except under very high magnification. Some of the gold is tarnished, and this condition also makes recovery difficult. The gold values have been determined to be highest in association with chalcopyrite and arsenopyrite. The silver occurs mostly in association with galena and tennantite. A small amount of native silver has also been observed occasionally. The galena, being softer than the other minerals, frees much better in grinding. Some oxidation of galena is present in the ore, as the non-sulphide lead content amounts to approximately 10 pct of the total lead. Some oxidation of sphalerite is also present in the ore. Microscopic examination of the zinc concentrate shows many grains in the minus 325-mesh to be half pyrite, together with the fact that some of the zinc is marmatite, makes production of a high-grade zinc concentrate very difficult unless recovery is sacrificed. In the grinding, it has been determined that the flotation feed must be maintained at 85 pet minus 200-mesh to free the minerals sufficiently to make the best economic recoveries. Table I illustrates the effect of fine grinding. It shows that the bulk of the recovered minerals is in the minus 325-mesh size and is the part of the minerals that is more readily freed. The pyrite concentrate is not given in the table because it contains practically no minus 325-mesh. Development of Present Flowsheet and Milling Practice The first milling operation started in 1938, with a mill capacity of 140 tons daily, producing a bulk gold-silver-lead concentrate. After several stages of expansion and changes of the mill flowsheet, the mill is currently treating 380 tons of ore daily and three separate concentrates are produced. In order of their importance and value, these are: (I) lead concentrate, (2) zinc concentrate and (3) pyrite concentrate. The present average grade of mill heads is: gold 0.11 oz, silver 4.00 oz, lead 2.50 pet, zinc 7.60 pct, copper 0.22 pct, iron 22 pct and 30 pct insolubles. Specific gravity of the ore is 3.8. During the period when bulk flotation mas practiced, the flowsheet was very simple. The ore was ground fine enough to liberate as much gold, silver and lead as possible. Necessary collectors and frothers were added in sufficient quantity

Jan 1, 1949

By C. H. Johnson

THE year 1952 has seen the continuance of the trend pointed out by Tell Ertl in this magazine a year ago, toward mechanization in metal and mineral mines. Outstanding progress has been made in the adoption of rock bolting in situations where, a short time ago it would have seemed inapplicable. New devices, better equipment, and improved practices are in part responsible for shifting fashions in mine development, stoping methods, and transportation systems. Only new mines, of course, can take the advantage of the new ideas that are being tested and demonstrated throughout the industry, but the old mines often show a surprising adaptability

Jan 2, 1953

By Benjamin Gildersleeve

Uniquely colored, thin-bedded quartzite is quarried between Crossville and Crab Orchard in Cumberland County, Tenn. It is produced in all sizes up to the limits of transportation from beds usually ranging in thickness from less than 1/2 in. to 6 in. The stone is very resistant to wear and weathering and is marketed throughout the country for many different purposes in exterior and interior construction. The annual production exceeds 36,000 tons, valued at nearly $1,000,000.

Jan 8, 1950

By A. J. Nicol

Field experience in uranium has shown it is most economical to ram through a drilling program to obtain maximum footage per drill hour. Drift surveys can then determine the course of the holes. Using this method is generally cheaper than paying the additional cost involved in using the drilling technique and equipment necessary to maintain straight holes. Factors Affecting Direction of Bit Travel: In all rotary-drilled holes there is an interplay of forces or conditions affecting the direction of bit travel. Rarely is a straight vertical hole obtained. One of the major factors is weight on a drill string. In looking at a joint of drill stem it is hard to imagine its being quite flexible, but flexing of the steel increases when many joints are made up together, and even a slight weight added to the upper portion causes a buckling or spiraling effect in the hole. The result is that the bit deviates from the vertical.

Jan 1, 1959

By A. W. Brune

Conventional methods of calculating the duty cycle of a mine hoist are awkward in that a number of items must be remembered or that they must be collected together in order to have all the calculated data in one place. A more convenient way is to tabulate all factors involved, permitting a ready evaluation of the problem. An example illustrates the convenience of such a table for either of two types of drums, cylindrical and conical. Assume the following conditions: The hoisting depth is 600 ft. Balanced hoisting is used. The weights of empty skip and ore are 6000 lbs and 12,000 lbs, respectively. Production is 3600 tons per shift. Net hoisting time per shift is six hours with a rest period of eight sec, top and bottom, per trip. Acceleration and retardation are each six sec. The diameter of the drum is seven ft; its face is four ft. The sheave has the same diameter. The equivalent effective weight of the drum reduced to rope center is 15,400 lbs. The weight of each sheave is 2100 lbs. 1 The rope is 1 1/4-in. improved plow steel weighing 2.50 lb per ft.

Jan 9, 1961

THOSE MARKED THUS * ARE MEMBERS, MARKED THUS ?ARE ASSOCIATES. THESE SIGNS DOUBLED INDICATE LIFE MEMBERS AND ASSOCIATES RESPECTIVELY. THE FIGURES AT THE END OF THE ADDRESS INDICATE THE YEAR OF ELECTION. HEAVY-FACED TYPE SIGNIFIES HONORARY MEMBERSHIP. *AARONS, J. BOYD, Vivian Gold Mining Co., Ltd., Harris, West. Australia. '05 *ABADIE, EMILE R., Cons. and Min. Engr., 214 Union Savings Bank Bldg., Oakland, Cal. '76 ?ABBÉ, MAX F., Prest., Abbé Engineering Co, 220 Broadway, New York, N.Y. '07 ? ABBÉ, PAULO., Secy.,Abbé Engineering Co., 220 Broadway, New York, N.Y. '07 *ABBOTT, CHARLES W., Min. Engr. Pioche, Nev. ?08 *ABBOTT, CLARENCE Chief EDgr., Iron Mines, Dic Tennessee Caol, Iron & R. R. Co., Bessemer, Ala. '04 *ABBOTT, JAMES W., Min. Engr: Ploche, Lincoln Co., Nev. '94

Jan 1, 1917

By John V. Beall

If there is one thing that makes a fellow feel like the years are catching up with him, it is to go through a second cycle in which the adequacy of mineral resources is being "viewed with alarm." The first time we experienced such a flap was in 1951. At that time, the United Nations convened a meeting at Lake Success to study ways and means of averting a crisis in minerals. Presently there is some sentiment being expressed about the mineral scarcities that will occur in the decades ahead, in view of world population trends and increasing per capita consumption of metals. To be greatly concerned about the adequacy of metal supplies is to be highly pessimistic about the capabilities of technology. As in the past, shortages will be of temporary duration for as far ahead as the most ambitious prognosticators are projecting. The study of mineral economics is a fascinating and surprising subject. The law of supply and demand is but a starting point. The iron ore market for the steel industry is an example which comes to mind because of our receipt this week of the United Nations report "Survey of World Iron Ore Resources."

Jan 1, 1970

By Swapan Bhattacharya

United States federal and state regulatory authorities require underground mine operators to adopt adequate measures to minimize material damage to the surface caused by mine subsidence. This paper presents an approach to define and determine the extent of material damage due to subsidence from underground coal mining. The basic steps involved in the development of adequate criteria have been enumerated together with the approaches and methodologies used.

Jan 1, 1984

By Robert W. Hunt

HAVING devoted considerable time to the investigation of the Clapp-Griffiths converter and the metal produced in it, it may perhaps be of interest to the Institute to learn the conclusions which I have formed. Of course, it is well known that the stationary converter of small size is the very oldest type of vessel used in the pneumatic process. Hence it will be only necessary to call your attention to the points which are special features of the Clapp-Griffiths. This converter has a slag tap-hole, situated at such a height in relation to the metal under treatment that, when the cinder is formed and boils up as the blow progresses, it can run off and thus be removed from contact with the iron, and will also be out of the way when the decarbonized metal is tapped into the casting ladle and the manganiferous alloy added. The manner of shutting off the blast, when the process is completed and the metal is being tapped, is another distinctive feature. The tuyeres are situated around the sides of the vessel, and enter the interior some little distance above the bottom; they are provided with plugs through the centers of which there are small openings. When the blow is completed, these plugs are forced forward into the outer orifices of the tuyeres, thus shutting off the blast, excepting the small quantity' entering through the passages named. While this is sufficient to keep the metal from running into the tuyeres, it reduces to the minimum the action of the blast while the metal is being tapped. Of course, this is of great importance, as in an ordinary stationary converter any delay in getting open the tap-hole means overblowing, and even while the first part of the charge is running out the oxidation is in frill force. Duplicate or movable bottoms are used, thus more than doubling the possible output of the plant. The pressure of' blast is quite light, never ex-

Jan 1, 1885

By Henry M. Howe

The death of Sir Lowthian Bell removes almost the last of the group of heroic leaders who made their age and ours the Age of Steel—a group which his luster and the luster of his peers, Bessemer, Siemens and Tunner, made one of the most brilliant, perhaps even the most brilliant, in the annals of induetry. Born on February 15th, 1816, in Newcastle-on-Tyne, he was the eldest son of Thomas Bell, an alderman of Newcastle, and of his wife Catherine Lowthian of Newbiggin, near Carlisle, in Cumberland, and was christened Isaac Lowthian, the name of his maternal grandfather. His father was born about 1788, and came in 1808 from Newbiggin to Newcastle, where he entered the office of the Cumbrian firm of Losh & Company, manufacturers of alkali and wrought-iron, at the Walker Iron and Alkali Works, at Walker, near Newcastle. Young Isaac Lowthian Bell was educated at Dr. Bruce's school in Newcastle, whence he went to Germany and Denmark, learning there German and Danish. On his return he studied at Edinburgh University, and then at the Sorbonne in Paris. As a student he already showed the remarkable character and application which later gained him such distinction. After studying the manufacture of alkali near Marseilles, he returned, and when about twenty years old (A.D. 1836) was employed in his father's firm, then called Losh, Wilson, & Bell. After spending a year in their Newcastle offices, and after visiting the important iron-making districts of France, Germany, Poland, and Austria, he took charge of their rolling-mills at. Walker, and profited so well by his opportunities, and especially by the teachings of his father and of Mr. John Vaughan (later one of the founders of the great firm of Bolckow, Vaughan & Co.), that he was made manager of the Walker works in or about

Jan 1, 1906

Time Now For Thinking In these turbulous times a natural restiveness is created among the younger men of the mining profession. Many of them are veterans of World War II and the question is raised in their minds as to whether or not to go back into military service. There is time to think about this question now and it is advisable to do so in order that snap decisions may be avoided if war is declared.

Jan 2, 1951

By J. R. Finlay

THE other day, I fell into conversation with two gentlemen who desired to improve the condition of the people; so that the talk was semi-political. They seemed to agree that I was inclined to be "con-servative," "reactionary," perhaps an "evolutionist," looking upon "reform" with suspicion. Finally I rejoined somewhat in this manner: "You attach to me phrases that I have heard all my life but which convey no meaning to me. It is quite true that I do not make a fetish of terms like reform, liberty, democracy and so forth; neither do I worship the idea that `things are good enough as they are,' `leave well enough. alone' and so forth. There is more satisfaction in building something up than in tearing something down, or in just maintaining something that is already built. Progress is a popular word; but what is progress? In my opinion it is comprised, so far as public welfare is concerned, of two elements: Improvements in production of goods and knowledge; improvements in keeping order." This substitute for politics, economics, reform, pro-gress, conservatism, radicalism, democracy, socialism, monarchism and all the phrases of public welfare may seem over-simple; perhaps it is, but at least it defines something. It seems to me to be at least worth attention.

Jan 4, 1922

West Virginia University, Engineering Experiment Station, Morgantown, W Va C E Lawall, Director. For copies of Bulletins or other information address the Director Two classes of the Bulletins published by the Engineering Experiment Station are of particular interest in this directory- Research Bulletins, and Extension Bulletins, or bulletins published for use in extension work They are. Research Bulletin 1, The conservation of natural gas in West Virginia (1918), 2, Acceleration stresses in hoisting ropes (1927), 3, Classification of gas wells for operation (1927), 4, Mining methods in West Virginia (1929), 5, The whiteware industry of West Virginia, Extension Bulletin 1, Electricity in mines, series

Jan 1, 1933

By Charles A. Ashburner

DURING the early part of August, 1880, I was directed by Prof. J. P. Lesley, State Geologist, to assume charge of the geology and mapping. of the Second Geological Survey of the anthracite codfields. I visited the region uninaumbered by any instructions other than this,—that I should submit a plan for making the sur-

Jan 1, 1881

By Campbell Hunter

PETROLEUM is found in almost every province in Persia. On the northern frontier, along the southern shore of the Caspian Sea, it is found near Anzelli and Shakhtesar and gas at Khoremabad. Oil is also found at Gumush Tepe, northwest of Astrabad, on the southeastern shore of the Caspian Sea. Further inland, to the south of Astrabad, oil is found at Schahkuh-i-balae, also on the margin of the Khorasan desert at Semnan, 115 mi. (35 m.) east of Teheran. Along the western frontier, from northwest to southeast, oil is encountered at Ouschachi, north of Lake Urumieh; in the province of Azerbaijan, at Zohab, Khanikin, and other places in the district of Kormanshah in the province, of Ardelan. Further south, in the province of Luristan, oil is found east of Mendeli and in the Pusht-i-kuh districts. Considerable quantities of oil are also obtained from Schuster, Maidan-i-Naphtun, Ram-Hormuz, Beheban, which are almost on a straight line, running northwest and southeast along the foothills of the Bakhtiari Mountains. At Ahwaz, in the province of Arabistan, oil has been found along another range of hills whose axis also lies in a northwest-southeast direction. In the Fars province, boring for oil has taken place at Daliki, and indications of oil are found at Kheri, Fasa, Darab, and other places. A gas show is also recorded at Kuhi-Sung-Atush in this province, 30 mi. (48 km.) east of Darab. In the south of Persia, oil is encountered on. Qishm Island, also at Ahmedi and other places north of Bunder Abbas. On the southeastern frontier, oil is found on the Sarhad range of hills. Thus, oil indications have been noted over a distance of approximately 1100 mi. along the western and 700 mi. along the northern frontiers of Persia.

Jan 2, 1920

We are glad to print the following letter from Herbert C. Hoover, who has recently been appointed Food Administrator, by President Wilson. Mr. Hoover has a tremendous task before him, and we are sure that mining engineers will give him their hearty support by responding to his appeal to stop the waste of food.

Jan 7, 1917

By Joseph Hartshorne

Ever since the introduction of the Siemens regenerative furnace, it has been recognized that a certain amount of gas is lost each time the furnace-action is reversed. This loss comes, first, from the gas which passes through the free connection between the stack and the gas-main, which exists during the time the reversing-valve is turning over; and, secondly, from the gas which is in the chamber and flues, from the hearth to the reversing-valve, and which flows back into the stack when the valve is reversed. The amount lost each time is, of course, small; but, since a furnace is reversed from four to six times every hour for, say, 300 days in the year, the aggregate is large enough to be well worth attention. The estimate has been published1 that, in Germany aloue, the loss from the first of the above causes amounts to 500,000 barks per year. The loss from the second cause is, of course, much greater.

Jan 1, 1907

By V. Annamalai, J. B. Hiskey

Abstract-The kinetics of copper cementation on a rotating disc of pure aluminum were studied as a function of chloride ion concentration, rotational speed of the aluminum disc, hydrogen ion concentration, copper ion concentration, and temperature. The optimum experimental conditions for all the parameters were determined. Chloride ion was found to destroy the naturally existing aluminum oxide film, and enabled the cementation reaction to proceed. A two-step rate, observed in most of the experiments, was attributed to the attainment of a roughened surface. An Evans diagram for the copper-pure aluminum system was constructed and utilized in predicting the controlling mechanism of the system. At low temperatures (<33°C), the rate with an experimental activation energy of 20.36 kcal mol-1 was controlled by the presence of an oxide layer. While at higher temperatures presence of an oxide layer. While at higher temperatures (>33° mol-1 was controlled by ionic diffusion. The deposits obtained were pure copper and not a copper-aluminum alloy. The amount of aluminum dissolved was determined for each experiment, and the maximum excess consumption was found to be only 40%. The structural characteristics of the copper deposits were studied using a scanning electron microscope. These observations indicated that the deposits were either bulbous, massive crystalline, or dendrites of different degrees of fineness depending on the experimental variables. The reaction rates seemed to depend on the deposit structures in a predictable way when a particular experimental parameter was varied.

Jan 6, 1978

By Sam F. Harrison

Most hydraulic system malfunctions make their presence known by sending out warnings that are loud and clear to the initiated mechanic, according to Aeroquip Corp. service engineers. To detect problems in many systems, they suggest that the use of four senses-sight, smell, hearing and touch-and a knowledge of how to interpret the information gathered are all that&apos;s needed to identify hydraulic malfunctions.

Jan 3, 1978