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By R. S. Dean

REQUIREMENTS for war materials have led to large scale experimentation upon metallurgical innovations. It is of interest to inquire what this may contribute of permanent value to our existing technology, as innovations adopted during war are apt to be discarded promptly at its end. This is because utilization of substandard ores usually requires a new technology for ore treatment, and a new use-pattern for employment of the products. Thus two very different problems are involved: first, devising a process; then, adopting its products by industry, with readjustments of the use-pattern if necessary. A new process may be as good or better than an old one, but the readjustments required for use of its products may prevent its general adoption if this implies scrapping existing plants and investing much additional capital. Metallurgical innovations are of three kinds: I. The use of substandard material in processes already established; 2. The grading-up of substandard material to render it more suitable for established processes; 3. The adjustment of technology and use-pattern to the raw materials that we have.

Jan 1, 1945

By C. G. Dunn

James, Jones, and Leak (JJL) conclude that growth-rate and orientation-distribution data obtained in a steep thermal gradient should be used with caution to account for isothermally produced recrystallization textures. I agree. However, it is not clear whether they conclude a) that the orientation dependence of rate of growth of secondaries in (commercial) silicon iron depends on both temperature and a temperature gradient or b) that, in applying rate data obtained in a steep thermal gradient, the isothermal annealing temperature must be close to the temperature for which the rate data apply. Also, it is not clear what tem-

Jan 1, 1967

By Peter G. Groer

Several methods1-3 are being used to determine the WL and individual Rn-daughter concentrations in uranium mine atmospheres. The best of these methods is the one given in Ref. 3. According to this method, the WL and the Rn-daughter concentrations are determined from the total a-counts observed during three consecutive time intervals. Its only disadvantage lies in the fact that rather involved calculations are necessary to convert the observed counts into WL or pCi/l (picocuries per liter). There are, however, counting intervals that give simple weighting coefficients for the observed counts. This fact makes it possible to convert from a-counts to WL or pCi/l with the aid of a graph. After some trial runs on a computer the following equations emerged as the basis for the most practical procedure: [ ] NA, N.., and & stand for the number of RaA, RaB, and RaC atoms per liter of air. C(t1,t2) denotes the counts observed from time t. to time t2 (in minutes) after the end of the 5-min sampling period. E is the detector efficiency and V is the flow rate in liters per minute. With an accuracy loss of less than -5% one finds from [Eq. 1] by adding the corresponding terms: If the WL would have been calculated according to [Eq. 2] instead of using the graph, the result would have been 0.31. Since the values used for C's under [Eq. 3] represent the exact number of counts from a Rn-daughter mixture in equilibrium with 100/3 pCi of Rn the exact WL of this mixture can be calculated easily. The exact value is: [ ] This shows that the method is quite accurate for the 0.3 WL domain. The precision of the method excluding errors made in reading the graph can be estimated with the help of the following formula: [ ]

Jan 1, 1974

By Arthur C. Spencer

IN extension of a suggestion already made to account for certain features observed in the Juneau gold-belt in southeastern Alaska,' it is the object of the present paper to indicate in detail certain conditions in which deformation of rocks under their own weight might lead to the production of fractures in which veins could be deposited. A direct, uniformly-distributed pressure of sufficient intensity applied to an elastic brittle mass offering strong resistance to deformation produces rupture. In a material of ideal properties the surfaces of rupture under such pressure would be shearing planes inclined at 45° to the line of force, unless there be preliminary deformation, in which case this angle would be greater than 45°. This general conclusion, resting upon ana¬lytical mechanics, is completely supported by the results obtained by Daubrée in experiments upon the deformation of wax and resin prisms under compression. Let us then first con¬sider one of Daubrée's diagrams. In the case illustrated in Fig. 1, four sets of fractures in two appproximately right-angled pairs (that is to say, in conjugate sets) were produced by end-wise compression of the square cross-sectioned prisms. These fractures cut the axis of compression at approximately equal angles, not varying greatly from 45°. The location of the four sets of fractures is obviously determined by the shape of the prism, since the material in each corner acts in a way as a buttress, permitting the bulging to take place most readily on the sides. By limiting the directions in which bulging may take place, results of a more simple nature could be obtained. Take, for instance, a square prism and place it between two fixed and

Nov 1, 1905

Howland Bancroft (A Modern Approach To Foreign Mineral Development, P 666) was born in Denver, Colo and attended the University of Colorado, University of Michigan and received a B S and B A degree From 1907 to 1912 he was with U S Geological Survey In 1911 he was involved in study of mining resources of Peru Mr Bancroft resigned from Federal Survey and opened offices as consulting mining geologist in Denver in 1912 From 1919 to 1920 he was a consulting engineer in San Francisco He was manager of Sinclair Panama Oil Corp in Panama City in 1920 From 1921 to 1923 he was vice president and managing director of same corporation He did independent examinations in Western states and an exploration trip through Turkey in Asia from 1924 to 1925 Mr Bancroft was vice president and general manager of Lago Petroleum Corp in charge of operations in Venezuela Mr Bancroft has spent time in 34 different countries in the world and in a number of different Latin American States, Europe, Asia Minor and Africa

Jan 1, 1952

By S. A., Taylor

IT is very difficult to arrive at exact figures for the cost of maintaining excess capacity of coal mines, but we can approximate the various items. To do this, I will take the Pittsburgh district of Pennsylvania and the other districts can be compared to this one. I believe we can take the depreciation item of plant ac- count as a whole and discount it over a period of 20 years; while this is high for some items it is low for others and I believe it is not far from a safe basis. This equals 5 per cent per year, and this depreciation will take place about as rapidly when not in use as when in operation. A fair value in the Pittsburgh district to- day for plant and houses is close to $4 per ton per annum. At 5 per cent this will equal 20 cents per ton per year. The item of keeping the mine in condition, free from water, etc., will be close to an average of 2y2 cents per ton per annum.

Jan 1, 1928

By George W. Maynard

(Pittsburg Meeting, March, 1910.) AT the Pittsburg meeting of the Institute, May, 1879, I made the first announcement in America of the results obtained by Sidney Gilchrist Thomas and Percy C. Gilchrist, ill their efforts to eliminate phosphorus in the manufacture of steel in the Bessemer converter and the open-hearth furnace.1 The first published statement in an American newspaper was a reprint of the first Thomas-Gilchrist paper, 2 which I sent to J. C. Bayles, at that time the editor. At the suggestion of many friends who were present at the Pittsburg meeting, and others who are cognizant of the beginnings of the process in the United States, and for the information of the younger generation of the iron and steel fraternity, I have thought it eminently proper that the history of the process in detail should be given where I made the first announcement and where the process has had its largest development. During my residence in England, from April, 1873, to February, 1879, and as a member of the Iron and Steel Institute since 1874, I was present at many of its meetings during those years. At nearly -every meeting the burden of discussion was the question of the use of pig-iron containing phosphorus in the. manufacture of steel by the Bessemer or the open-hearth process. In my biographical notice of Thomas;3 read at the New York meeting of, the Institute, February, 1885, I show that the working-out of the process was not a hap-hazard or accidental inspiration, but the culmination of many years of investigation of experiments and theories which had been carried on and advanced by chemists and metallurgists at home and abroad. 1 Trans., viii., .5 (1879-80). 2 The Iron Age, vol. 22, No. 17, p. 3 (Oct. 24, 1878). 3 Trans.. xiii., 785 to 791.

Jul 1, 1910

By FREDERICK C. BROWN

THE practice of fine-grinding is now being so successfully - carried on in some fields, notably in West Australia, and its advisability has been so frequently pointed out' that the matter in this paper is not put forward as being new ; its chief object being to call attention to the importance of fine-grinding in the treatment of comparatively low-grade ores. I have been engaged during the last five years in the cyanide-treatment of ores in the Ohinemuri district (North Island), New Zealand, and I consider that, in the near future, extremely fine-grinding (almost sliming) will become a very important feature of the milling-methods in this field, since it seems absolutely necessary to reduce the most of ores to a very fine state of division if a high extraction is to be obtained; and, in most cases, the extra percentage of saving will leave a good margin above the increased cost of treatment due both to the fine-grinding and to the interest on the capital spent for the grinding-machinery. The average ore of the Ohinemuri field is composed of a quartz-gangue with some calcite, carrying the gold-value in the form of an alloy of gold and silver in about equal proportions, and the silver-value in the form of mixed sulphides of silver, usually associated with a considerable amount of iron pyrites. In the upper levels, the ores are decomposed and carry large quantities of black manganese oxide and some iron oxide, but, as. depth is reached, the decomposed ore gives place to sulphides and, in some mines, rhodonite, manganese silicate, is present in fairly large quantities. The average value of the

Jan 1, 1906

By Rclssell Gibson, F. S. Turneaure

The tin deposit of Monserrat; Bolivia, consists of one major vein 1600 m in length. The ore is unusual because of the notable quantity of teallite, even though cassiterite is the principal tin mineral. The deposit, formed at shallow depth under a wide range in temperature, may be classed as xenothermal. Polished sections reveal a complex history of replacement, with low-temperature minerals deposited before high-temperature minerals.

Jan 1, 1950

By Charles Hart

THE-report of the advisory committee to the U. S. Bureau of Mines, on the use of oxygen in metallurgy, brings to the art of steelmaking a radical change in the method of operation of the many processes of this widely diversified industry. When completed, the improvements suggested by the use of oxygen will be far-reaching and revolutionary. As to its effect upon the iron blast furnace, the use of oxygen should be as important as any of the improvements in the art of iron smelting and should take its place beside the German "Hochofen" which was the first attempt to use a shaft for preheating the stock, and beside the hot-blast stove which heated the blast before entering the furnace. The former initially produced molten iron and the latter made unbelievable economies in fuel consumption. It would seem that a discussion of this paper would be best served by following the conclusions on page 17 of the report and analyzing them seriatim. 1. (a) A decrease in costs, due to higher smelting heats is only attainable by taking full advantage of these heat units. This is affected by, adding additional ore to the burden which in turn increases production and yields a larger tonnage upon which to figure costs. These economies appear in decreased cost per ton of iron for coke and limestone consumed, and a proportionate reduction in all items entering the cost above materials. We can take no exception to these. premises. It is a well-known fact that silicon in the iron and sulfur removed" are the result of hearth temperature, other matters remaining constant. To a practical furnaceman the most satisfactory manner of controlling a furnace is by increasing the burden. It is not necessary, therefore, to consider the question of refractories, for this discussion presupposes that the temperatures in the furnaces will be kept practically where they now stand for making the various grades of iron. The same situation obtains in regard to the height of the furnace, which, as intimated, was one of the great strides forward in this art, and its abandonment at this time, is inconceivable. The shaft prepares the stock so that at each succeeding step we have exactly the proper conditions. All the stock entering the furnace is dried and preheated. The limestone is calcined by sensible heat practically at no cost, for this is sensible heat which otherwise would pass from the top with the gases. Under normal conditions, external calcination has been attempted without tangible results. Under normal average furnace operation, limestone requires about 760 B.t.u. for calcination and the loss of sensible

Jan 11, 1924

The annual report of the Secretary of the Southern California Local Section for the year ending May, 1919, says that the Section was called upon to give all the assistance possible for the different Liberty Loan drives, for the Red Cross drives and not only in the canvass of our membership, but the canvass of all of the mining companies represented in this city. The committee on the Red Cross drive on which we were represented raised a larger proportion of the total amount than any other in the city. The subscriptions for Liberty Bonds from the members of our' Section that were credited to the Committee of the Joint Technical Societies exceeded in amount the subscription from the members of all the other technical societies combined. Members of our Section slid splendid and efficient work throughout the first half of the year at the Red Cross headquarters in this city, and under the leadership of A. B. W. Hodges and F. B. Close, systematized the work of handling the enormous quantity of material that passed through that organization. Mr. E. A. Montgomery directed the canvass of the mining companies of this city in the bond drives, and the Executive Committee did its part in solicitation among the mining engineers. The Section, together with the local sections of the American Chemical Society, American Institute of Architect, American Institute of Electrical Engineers, American Society of Civil Engineers, American Society of Mechanical Engineers, and the local Engineers and Architects Association, forms what is called the Joint Committee of the Technical Societies. of Los Angeles. The honor of having the first president of this combined organization of engineers was given to us with, the election of Mr. Seeley W. Mudd. Upon Mr. Mudd's entering the service, Mr. George A. Daman of the Electrical Engineers was elected to the position and served splendidly during the latter part of the year. It devolves upon this Section to be represented upon this Joint Committee by three members, and it is our duty to supply a speaker once in six weeks to address the engineers in attendance at the weekly luncheon. During the year not a few of the most prominent men of the engineering professions have spoken upon subjects of the greatest interest to us all. Had it not been for the organized team work in the engineering profession available through this Joint Committee, there would have undoubtedly been passed in the recent session of the legislature of this state a bill for licensing and registering all professional engineers in this state, which, in the opinion of your Executive Committee and a large proportion of the membership of this Section, would have fallen far short of either protecting the engineer or protecting the public from impostors. That the public is awakening to the importance of what our National Society represents in the profession of mining engineering can be well inferred from the increasing number of inquiries your Secretary receives regarding the reputation of mining engineers. The necessary qualifications which a membership in the Institute requires and the membership of an engineer in this National Organization is more and more a criterion as to the ability of an engineer who represents himself as such, to the general public.

Jan 9, 1919

By R. A. Pallanch

IN his recent paper, "The Controversial Art of Flotation," (Mining Technology, March, 1944) E. H. Rose states that "flotation is a science in so many variables that only art can blend them." This statement is apt. It contains meat. In other words, a valid scientific reason is behind every flotative effect. Some of these reasons we understand, but much the greater number of them still escape us. This does not prevent us from "going places," as familiarity and experience with the problems result in an increasingly intelligent and artful handling of these effects. Hypotheses are built up by the individuals concerned to explain certain happenings. Many of these hypotheses have to be abandoned when placed under the glaring scrutiny of actual trial. A few survive the severest of tests, come through unscathed, and are elevated to the rank of theories, something susceptible of certain chemical and physical explanation, under the conditions of the particular plant concerned. If these theories continue to hold water under all the variations existing in most milling plants, they gradually become accepted as facts in the minds of the plant operators. But-and here is a big BUT-these so-called facts may fall down completely in another plant working under an entirely different set of conditions. In other words, each plant tends gradually to build up its own facts, which may or may not be facts at another operation.

Jan 1, 1945

By T. T. Read

JAPAN'S iron and steel industry has always been closely connected with military strategy. Many years ago it became evident that the country's iron-ore resources were too small to support any extensive industry. As a result a belief in the imperative necessity of securing such resources has influenced Japan's political and economic policy in the Far East. Iron-ore developments in China are too well known to need repeating except to note that they have been rather unsatisfactory to both China and Japan. The ore deposit at Tayeh, in China, is not as large as was first believed and, though that and other sources of supply in China proper are now furnishing Japan a little more than a million tons of ore yearly, it cannot be counted upon as a large permanent source of supply. The deposit in Shantung proved so disappointing on further exploration that operations there have, so far as I know, long since ended. The operations at Pen-bsi-hu, in South Manchuria, which C. F. Wang de¬scribed in the A.I.M.E. TRANSACTIONS for 1918, Vol. 59, were reported to have yielded 84,000 tons of pig iron in 1928 and about 50,000 in 1935, so they seem to be going back.

Jan 1, 1937

By R. F. Slack, J. C. Draper, J. A. Younkins

In 1959, the Duquesne Light Co. was faced with the problem of moving more than 40 million tons of bituminous coal in Greene County, Pa. The coal had to travel a distance of about 4 ½ miles from a new mine portal in Rocky Run Valley to the company preparation plant and loading facilities on the Monongahela River. After careful study of this immense transport problem, Duquesne decided that the belt conveyor system described in the following pages offered the best solution. This system, now in operation, is probably one of the four or five longest permanent overland conveyor systems in existence. The general layout of the entire system is shown in Fig. I. A detailed description of the salient features of the system is presented below. THE MINE The valley of Rocky Run where the system begins is very, very narrow and very steep. It was chosen as the site of Duquesne's new mine portal because it was the only place on this particular property where the Sewickley coal seam cropped out. The valley also had two other advantages. First, it fronted on a state road and, second, it offered a site where some 4 million gallons of water could be stored for use in dust-allaying sprays needed in the mine. The company elected to construct a drift mine in the valley because this would require neither the hoisting time of a shaft mine nor the walking time of a slope mine. As part of the mine construction project, the valley was leveled by relocating its stream and filling its center with material cut from each side.

Jan 11, 1966

By Floyd E. Bliven

A century ago, Thomas Carlyle sketched the Emblem of the Wasting Candle in one of his papers. "Terar Dum Prosim" he wrote under the candle-" May I be wasted so that I be of use." The application of his reasoning is an excellent guide for a discussion of the scrap problems of today. The General Electric Co. has addressed itself to the need of proper and careful preparation of scrap metals for many years. A supervisor of salvage directs this work in each of the works. Generally he is an engineer and has had broad factory training. He gives general direction to the collection, preparation and disposition of scrap materials. He operates the extensive facilities which each works has provided for the centralization and control of scrap accumulations, and also initiates studies leading to the reduction of scrap accruing from machining and assembly operations. r We recognize that each industry, each factory, each locality faces a different set of conditions. Irrespective of size, in a plant employing 20 men or a large works with 15,00 employees-certain fundamental principles can be applied for organization and the collection of scrap. The manufacture of electrical apparatus is a highly complicated intricate business. In one area we make electronic tube and adjacent buildings house the manufacture of steam turbines. Both are instruments for power-different in size and in many cases serving different fields of application. Unlike the great industries that build automobiles, trucks, or engines where repetitive operations, once solved, set the stage, electrical manufacturers' plants are large jobbing shops. Therefore, we must carefully plan every step in handling the scrap that "in so wasting to produce the finished motor or locomotive-we can return this product to reprocessing and ultimate use." ESSENTIALS FOR SALVAGE EFFICIENCY The essential steps for an efficient salvage department are: I. Selection of Personnel.-An able foreman would be a man of broad experience and understanding-one who commands the respect of the entire foreman group as well as that of his own men. In the interest of clean scrap, it is necessary to acquaint the foremen in the separate manufacturing units with the need of careful segregation in the shop and the best methods of obtaining it. At least 40 per cent contact time should be devoted for this purpose. 2. The physical equipment of the salvage department should be devised and selected to handle complete, at one point, all scrap operations. Bulky materials as produced by some large shops can be economically placed in salable shape at the divisional point. Because salvage

Jan 1, 1943

By GEO H. DEIKE

NOT much activity has been evident during the past year in the establishment of co-operative scholarships but the interest among the coal-mining companies is more pronounced than ever. This is apparent from the replies received to a letter sent out by the Committee on the Promotion of Student Interest in Coal Mining to over 120 coalmine operating officials. With that letter was forwarded a bulletin issued by the school of mineral industries of The Pennsylvania State College entitled ?Industrial Scholarships ? a Partnership of Industry and Education.? In that circular was outlined the need for trained men in the war and postwar world, and particularly as such demands pertain to the growth of the mineral industries.

Jan 1, 1943

By WILLARD HAYES

(Glen Summit Meeting, June, 1911.) THE determination of the question whether the Mayari and Moa mining-claims of the Spanish-American Iron Co. have been rightly denounced under the third section of the law of bases rests on the findings in the following questions of fact: 1. Is the mineral an iron-ore? 2. Is the iron-ore a bog iron-ore? 3. Is the iron-ore ocher? 4. If ocher is present, can it be mined separately and independently of the iron-ore ? 1. IS THE MINERAL AN IRON-ORE? Since the material is shown by a large number of analyses to contain from 41. to 50 per cent. of metallic iron and less than 0.02 per cent. of phosphorus, and since it has been and is being actually used on a commercial scale for the production of iron and steel, it must be classed as an iron-ore. 2. IS THE IRON-ORE A BOG IRON-ORE? Bog iron-ore has certain invariable characteristics of chemical composition, physical appearance, geological relations, and origin by which it can always be recognized with certainty. In chemical composition, it is the hydrated sesquioxide of iron, limonite, or a mixture of limonite and other closely-related iron hydrates. It never contains the anhydrous oxides-hematite or magnetite; is never magnetic, and never contains either nickel, chromium, or cobalt oxides. On the other hand, it is invariably high in phosphorus-content. In physical appearance and texture it is a yellow or reddish-brown amorphous spongy material, and always contains water-worn sand-grains, silt, clay, and plant-remains. In its geological relations it is wholly independent of the rock

Mar 1, 1911

By William Catron, Cyril U. Colledge

BECAUSE the rich La Colorada orebody of the Cananea Consolidated Copper Co. does not outcrop at surface, after its discovery (by churn drill) and before mining was begun, a large amount of development work was done to learn the shape and extent of the ore and to provide for economic and effective mining. As these openings progressed, the actual shape of the orebody became known and with this knowledge came the realization that mining this rich and unusual deposit without loss of ore or danger to workmen presented several difficult problems. This paper will describe one of these problems; namely, the handling of an inverted cone-shaped core of barren rock, on the periphery of and below which the ore occurred. It was clear that as the ore was mined out from around and under this inverted cone of rock, weighing about 3,000,000 tons, it would hang over the workings, held suspended only by its own tensile strength and threatening to crash into the stopes below with disastrous results to men and mine. The method of mining developed during the years 1928, 1929 and 1930 anticipated and provided for the eventual collapse of this core of rock. In November 1936 the core settled down gradually on the edges of the stopes descending a total of about 50 ft. vertically. The men in the stopes had ample warning and no lives were endangered. There were no air blasts in the mine. The core broke loose from its top support at the 500-ft. level along old fracture planes and evidently is crushed to the ninth level. Movement was of short duration; the following shift went to work in the stopes as usual. No ore was lost. GEOLOGICAL STRUCTURE The shape of the orebody is illustrated in Fig. 1. The geology of the Colorada orebody has been described by V. D. Perry1 and by W. G.

Jan 1, 1938

OFFICERS AND DIRECTORS For the year ending February, 1932 PRESIDENT ROBERT E. TALLY JEROME, ARIZ. FREDERICK W. BRADLEY SAN FRANCISCO, CAL. WILLIAM H. BASSETT,P WATERBURY, CONN KARL EILERS NEW YORK N. Y.

Jan 1, 1929

By Howard S. Bryant

FROM the viewpoint of the oil producer, the oil refiner, the oil marketer, and the investor, in oil securities, a brief picture of the crude oil supply and demand in the present critical season of the year will be timely and interesting. Although crude oil production has been in a comparatively poor statistical position this year, increased sales and sustained refinery and crude oil prices have allowed increased profits for many oil companies. The large amount of crude oil going into storage during the present period of peak consumption, just previous to the major yearly fall decline in consumption, has caused oil producers to make plans to leave the oil in the ground for the present in several of the areas of large flush production. The present moment is looked on as the turning point in the current year.

Jan 1, 1929