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By F. Ernest Brackett

Much new data on the flow of gases have been discovered by recent experiments by the United States Bureau of Mines and others. Although additional investigation is still desirable, the information now collected seems sufficient to attempt a tentative coördination of the friction factors. This study is confined entirely to fluid friction when the density throughout the duct is so nearly constant that it may be so considered. In the subsequent discussion the following notation is used: v = mean velocity of fluid in duct, feet per second. v' = mean velocity of fluid in duct, meters per second. R = hydraulic radius of duct, feet. R' = hydraulic radius of duct, meters. S = the hydraulic slope. P = pressure absorbed by friction, pounds per square foot. p = pressure absorbed by friction, pounds per square inch. p' = pressure absorbed by friction, kilograms per square centimeter. A = sectional area of duct, square feet. O = perimeter of duct, feet. L = total length of duct, feet. L' = total length of duct, meters. d = diameter of a cylindrical duct, inches. w = density of the fluid, pounda per cubic foot. g = specific gravity of the fluid compared with water = w % 62.4. C, k and B, coefficients for formulas using English measures. C' = metric coefficient, v' = C'R'S. n = coefficient of roughness for English or metric units. The basic formula for the flow of all fluids at constant density appears in the three following forms, which may be denominated: (a) The slope formula, v = CRS (b) The ventilation formula, " n = (c) The pipe formula, C is Kutter's coefficient, which is extensively applied to the flow of water in ducts and channels of all kinds; E is Atkinson's coefficient, used principally with air in ventilation problems; B is a coefficient conveniently adapted to studying the flow of water, gases and vapors in pipes. 312

Jan 1, 1927

By Bruno Nordberg

HOISTING is one of the earliest endeavors of man with machinery, for hoisting was probably used by the early Egyptians. Treadmills were used for general hoisting until early in the nineteenth century and it was a short step only to attach a Watt steam engine to the rope drum of a hoist. One of the earliest steam hoists was built for a coal mine at Frisne, near Valenciennes, France. It was a remarkable piece of engineering created by James Watt in 1811, using a wooden drum on a vertical shaft. This followed the crude hoist by Holtzhausen in 1803, which used a drum of wood on a horizontal shaft.1 In this country there were examples of crude mine hoists, which have been developed into the efficient machines in use today. African and Australian mines show examples of both extremes, and have an array of fine hoisting equipment exemplified in those built by British manufacturers. The influence of both English and American engineering in hoisting is interestingly evident in Canada. The information available to the writer does not reveal this to be true of South Africa, although American-built hoists have been furnished. Mining camps develop their own style of equipment, adapted to local conditions. For instance, the Butte mining district adheres to the straight drum with friction clutches, because of the great number of levels from which hoisting is done or to which men and material are lowered and the necessity for hoisting or lowering unbalanced. The north Michi-gan copper country uses both straight and cylindroconical drums and hoists continually in balance, so that the drums are not clutched to the main driving shaft. The Joplin mining district, Missouri, has its own peculiar small hoists. Other individual mines or localities in which a number of mines have been developed show individualisticc types of hoists, depending upon their particular problems. In each instance, however, the particular problem must be carefully analyzed, as conditions are seldom so near the same that a number of identical hoists can be used to advantage.

Jan 1, 1940

By Henry Wurtz

Jan 1, 1880

By Paul Weir

PRODUCTION METHODS in the bituminous coal mines in the United States are undergoing many changes. Although the primary object of these changes is the production of a better product at a cheaper cost there are other considerations such as the improvement of conditions under which miners live and work. The almost complete unionization of the manual workers in the industry during the past four years has 'brought with it a stabilization of wages on a relatively high basis and of hours of work per day and per week on a relatively low basis. With differentials in wages between producing districts firmly established, and with a nation- wide and uniform application of in-

Jan 1, 1937

By Henry Wurtz

HERACLITUS, a sage of antiquity, called the dark philosopher, who refused a throne, preferring a hermit's cell, propounded, twenty-four centuries since, the maxim : [ ] War (or strife) engenders all things. This, though probably intended by Heraclitus to apply especially to the internal forces of nature, is often said, with equal reason, of the affairs of men. Controversial strife, whether fortunately or unfortunately, is a crucible through which all new discoveries in science, and all technical applications of science must pass-a test which they must all endure before they can become so vitalized as to germinate, so to speak, take root in the human mind, grow tip, and overspread the earth. The greater the number and the power of the elements arrayed against such a growth, and of the influences hostile thereto, the greater should be the inherent vitality of the germ, the more strenuous, skilful, and persistent its cultivators and upholders. During the decade last past we have had, in spite of the severe stringency of the times, an active growth of this kind in progress, whose prospective importance it would now be difficult to overrate. This is the movement which has for its motive the idea that, generally speaking, fuel should be gaseous in form, and which has for its goal the introduction into general public use of gaseous products, made by cheap and rapid processes and on a gigantic scale, distributed throughout our cities and towns in distribution-systems which shall be proportionately gigantic, and sold at prices which will bring such fuel within the means of the poorest householders. Personally, for ten years past, the writer has never failed, on occasions public or private, to urge his belief that the realization of this idea, deemed by him a certainty of the future, will bring about

Jan 1, 1880

By Albert Sauveur

As THE years go by, names of distinguished metallurgists will be added to the list of Henry Marion Howe lecturers, and now and then an illustrious one, for to be chosen to deliver the Howe lecture will be, I do not hesitate to predict, a highly coveted honor. I pray, therefore, your indulgence, if I confess to a feeling of gratification in having been appointed the first of these lecturers. It does not follow, however, that I am losing all sense of proportion and that I have an exaggerated idea of the little I have been able to contribute to our knowledge of iron and steel. Indeed, I fully realize how small were my claims to so great a distinction. I realize, also, that those entrusted with the task of selecting a lecturer were actuated, in coming to a decision, by their knowledge of the long and intimate friendship that had existed between the leader we have lost and myself. For their generous impulse, I thank them from the bottom of my heart; and with becoming modesty, I take up my task as the first Henry Marion Howe lecturer. It would be pleasant and indeed most appropriate to devote this entire lecture to a eulogy of Henry Marion Howe and his work, but how short the time for so large an undertaking and how inadequate my qualifications! On Aug. 28, Sept. 4, 11, and 18, 1875, a series of articles appeared in the Engineering & Mining Journal entitled "What is Steel?" With one exception, these constitute the first professional paper of Henry Marion Howe. That was nearly fifty years ago, three years after graduating from Harvard University. He was then but twenty-seven years old and already his keenly inquisitive mind was actively at work. There is a touch of romance in this young metallurgist who, on entering his. scientific career, destined to be so brilliant and so fruitful, on the very threshold of it, seems to have selected as his motto "What is Steel?" Like a knight-errant of science, he started on his quest for an answer to that question, a quest which was to last forty-seven years and which death only brought to an end. And while thus engaged how many wonderful messages we received from him, each one bringing us nearer to the goal! How illuminating, inspiring and encouraging were those messages! How well-equipped he was to wrench from nature some of the secrets she so jealously guards! How broad his learning and how clear his

Jan 5, 1924

By R. L., Fullman

During the past year there have been a number of significant investigations that have furnished evidence on the driving forces governing grain growth and on the role played by boundary impurities. Thus Burke has shown that in high purity alpha brass the rate of grain growth in the earliest stages is approximately inversely proportional to the existing grain size. This relation agrees with one derived by Zener assuming that surface energy was the driving force in grain growth. Also in confirmation of the surface energy hypothesis, Burke found that growth virtually stopped when the grain boundaries or even only the grain corners were melted.

Jan 1, 1949

[Title PAGE 1 Contents Page 1 Officers and Directors5 Standing Committees 6 Professional Divisions7]

Jan 1, 1928

[Trans. No.Place Date Vol. Page 1. Wilkes-Barre, Pa.* .... May, '71.. 1 8 2. Bethlehem Pa Aug., '71.. 1 10 3. Troy N. 'l Nov., '71.. 1 13 4. Philadelphia, Pa Feb., '72.. 1 '17 5. New York, N. Y.• ....May, '72 1 20 6. Pittsburgh, Pa Oct., '72.. 1 25 7. Boston, Mass Feb., '73.. 1 28 8. Philadelphia, Pa.' May, '73.. 2 3 9. Easton, Pa Oct., '73.. 2 7 10. New York, N. Y Feb.. '74 2 11 11. St. Louis, Mo' May, '74.. 3 3 12. Hazleton, Pa Oct., '74.. 8 8 13. New Haven, Conn....Feb., '75.. 8 15 14. Dover. N. J.' Mav. '75.. 43] [ ]

Jan 1, 1925

By James A. Barr

Phosphate rock is a natural rock containing one or more phosphate minerals usually calcium phosphate, of sufficient purity and quantity to permit its use, either directly or after beneficiation in the manufacture of commercial products.1 The principal minerals in phosphate rock have the apatite structure which may be represented by the type formula: Ca10(X2) (PO4)6 where X represents the hydroxyl group (OH), chlorine or fluorine, either singly or collectively. The calcium may be partly replaced by sodium, magnesium, and other positive ions such as manganese, strontium, lead, uranium, cerium, yttrium and other rare earths. The PO4 radical may be partly replaced by small quantities of UO4, AsO4, SiO4, CO3, SO4, or Vo4. A typical commercial rock is usually a calcium phosphate containing 3 to 4 pct fluorine, the major impurities being limonite or other iron oxides, clay, aluminum phosphates and silica as quartz sand. A little vanadium is present in most of the domestic rock deposits (except the Tennessee Brown Rock), according to Jacob, Hill, Marshall and Reynolds! A little uranium occurs in the Florida leached zone, as will be brought out later. The chemical analyses are reported as P205, or tricalcium phosphate Ca3(PO4)2, the latter often designated by the trade name BPL (bone phosphate of lime). Commercial analyses usually report iron and alumina as oxides, lime as CaO and silica or insoluble. Colony3 examined many samples of apatite, staffelite, dahlite and American phosphorites and concluded that all have identical X-ray diffraction patterns. The phosphates in the phosphate rock have very minute crystalline structures. The mineral apatite Ca3(F.Cl) (PO4) 3 is the principal primary source of the element phosphorus, and occurs widely distributed in igneous rocks but rarely in a minable mass. Only about 12 pct of the world production of phosphate rock comes from primary apatites; the remainder is derived from secondary phosphorites. These phosphorites have been formed by the alteration of sediments by solutions containing phosphoric acid. Such solutions have come from the weathering or leaching of igneous rock containing apatite, bone deposits of prehistoric animals, marine life or guano deposits. These phosphorites are mostly alterations of phosphatic limestones. The sedimentary phosphate deposits are of marine origin and may have been enriched by subsequent solution of the more soluble calcium carbonate by waters containing carbon dioxide, by physical concentration by wave action, and by redeposition of the dissolved phosphate ions. Uses of Phosphate Phosphorus is the spark of life and is the structure builder and one of the main elements of plant food (fertilizer). Without phosphorus, life cannot exist. A "complete" plant food[t] in addition to phosphorus compounds contains potash, which acts as a catalyst to convert nutrients to useful forms, nitrogen to supply the growth element and many minor elements. The cycle of supply of phosphorus is from the apatite to solution and soil, absorption of plant life, decay and return to the soil or by animal life feeding on the plants. With insufficient supply of phosphorus in vegetation, life is not prolific. If crops are removed from

Jan 1, 1960

By P. Pietrokowsky

RECENTLY a comprehensive investigation of the various sigma binary alloys was published by Duwez and Baen.1 It was shown that the following conditions are necessary for the formation of the sigma phase: (1) the difference in atomic diameters of the two alloying metals must not be more than about 8 pct; (2) of the two elements which form sigma, one must exhibit a body-centered cubic structure while the second metal must be face-centered cubic, at least in one of its allotropic forms. In addition, a tetragonal unit cell was proposed and powder patterns of six sigma phases were indexed for d spacings greater than 1.640 kx. Since the indexing, based on tetragonal symmetry, led to only fair agreement, the possibility of sigma being orthorhombic was investigated. Various methods for indexing orthorhombic powder patterns are de- scribed in the literature.' The method used in this investigation was a graphical examination of the differences in values of sin' 9 for the adjacent lines of the powder diffraction pattern. This method led to a complete indexing of the Cr-Co (60-40) pattern. Because of the strong similarity between the various sigma alloys, it was then possible to assign indexes to the patterns of Fe-Cr (50-50), Fe-Cr-Mo (30-30-40), Fe-V (50-50), Co-V (50-50), and Ni-V (50-50). The values of sin' 9 and indexes of the six sigma alloys, together with visually estimated intensities, are presented in table 1. In general, the similitude between the six patterns is quite good. For spacings greater than 1.75 kx a few differences are noticeable. In the Ni-V pattern, no (320) exists and the two strong lines (030) and (031) are separated by only two lines of lower intensity, unlike any of the other sigma patterns. However, very little is known about the Ni-V phase diagram and it is possible that the equal atomic percentage composition in this system lies in a two-phase region. At lower spacings there is a close analogy between the patterns. The planes

Jan 1, 1951

[Trans. No. Place Date Vol. Page 1, Wilkes-Barre, Pa.* .... May, '71.. 1 3 2. Bethlehem, Pa Aug., '71.. 1 10 3 Troy, N. Y Nov.,'71.. 1 13 4. Philadelphia, Pa Feb., '72.. 1 17 6. New York, N. Y •.... May, '72.. 1 20 6. Pittsburgh, Pa..:.Oct., '72.. 1 25 7. Boston, Mass Feb., '73.. 1 28 8 Philadelphia, Pa.' May, '73.. 2 3 9. Easton, a Oct., '73.. 2 7 10. New York, N. Y Feb., '74.. 2 11 11. St. Louis, Mo.* May, '74.. 3 3 12. Hazleton. Pa Oct.. '74.. 38 13. New Haven, Conn Feb., '75.. 3 15 14. Dover, N. J.' May, '75.. 4 3 16. Cleveland, 0 Oct., '75.. 4 9] [ ]

Jan 1, 1925

By E. O. Wagner, V. F. Parry

This paper summarizes investigations during 1949 on three pilot plants for drying low-rank fine cool by entrainment in hot gases. Detailed operating results on processing seven coals having moisture ranging from 24 to 62 pct, formulas and data for calculating performance of large units, and general conclusions on the problem of drying fine coal are presented.

Jan 1, 1950

By I. R. Kramer

The stress associated with the high-dislocation layer at the surface of deformed aluminum crystals was measured by progressively polishing the specimen and determining the change in the initial flow stress when the specimen was reloaded. This surface stress increased linearly with strain in the Stage II and Stage III region. The depth to which the high-dislocation layer extends was found to be 0.0025 in. The influence of the surface layer on Stage I is discussed and it is shown that Stage I ends when, on the secondary slip system, the difference between the applied stress and the opposing stress due to the surface layer is equal to the critical resolved shear stress. In previous papers'-3 it was shown that the surface exerts a pronounced effect on the plastic-flow characteristics of metals. For fcc metals it was possible to increase the extent and decrease the slope of Stages I and II and decrease the work-hardening coefficient of Stage II by removing the surface of the specimen continuously during the deformation process.2,3 More recently,L it was shown that the activation energy for plastic deformation and the activated volume were also influenced by the surface. These changes were related to the existence of a high concentration of dislocations in the region near the surface of the deformed specimen and it was concluded' that the effective stress, T, acting on a dislocation was T = Ta-Ti-Ts [1] where 7, is the applied shear stress, Tj is the internal stress, and TS is the stress associated with the surface region containing the high concentration of dislocations. From Eq. [I] it is seen that the effective stress, 7, acting on a dislocation is a function of 7,. Therefore 7, becomes important in any description of the work-hardened state. In this paper the value of 7, as a function of strain and its variation with depth are reported for aluminum single crystals. In particular, it will be shown that the end of Stage I occurs when the net stress, 7, on the secondary slip system is equal to the critical resolved shear stress. To measure Ts, single crystals of aluminum were deformed in tension to various strains, whereupon the load was removed and a known amount of metal was removed by electrolytic polishing. The differ- ence between the final flow stress before the specimen was unloaded and the initial flow stress upon reloading is designated as ?Tp and is the decrease in the stress due to the removal of the surface layer in whole or in part. The value for Tp is taken equal to -Ts. EXPERIMENT PROCEDURE The details of the tensile apparatus, method of electrolytic polishing, and crystal preparation were the same as those used previously,1"3 The single crystals were 1/8 by 1/8 in. in cross section with a 3-in. gage length. The initial purity of the aluminum was 99.997 pet. The specimens were held in vacuo at temperatures 50°C below their melting points for 16 hr and furnace-cooled. Just prior to the application of the tensile stress the specimens were electrolytically polished to remove 0.004 in. from the thickness. This latter operation was conducted after the specimen was placed in the tensile apparatus. The tensile tests were conducted at a strain rate, i, of 10"5 sec-' and a temperature of 3°C. The aluminum crystals used for the determination of 7, are designated A1-3-12 and A1-116. The orientation of the various crystals used throughout the investigation is shown in Fig. 1. The ?Tp values for specimens A1-3-12 as a function of Ax were determined mainly at four strain levels, i.e., ? = 0.0217, 0.0381, 0.0593, and 0.075, where Ax is one half of the total reduction of the thickness after polishing and ? is the re-

Jan 1, 1965

How Mining Engineers Will Fare in 1977 Mining Education- The State of the Discipline Coal Mining Technologists are a New Force in the Labor Pool Trained Manpower Provided by Mining Technology Programs Putting New Engineers to Work-A Management Perspective

Jan 1, 1977

By Jay A. Carpenter

WAR?S impact on Nevada mining and rnetallugrcal operations has brought about a rapid rise in the gross value of the ores mined and milled for the atratezic metals, and a sharp decrease in that for the precious metals. The State?s total production over the present war years will averaged out 10 per cent above the good record of $39,000,000 in 1937. However. this annual production is low in contract to that of nearly $47,000,000 in 1877 in the days of the great bonanza on the Comstock, and that of nearly $49,000.000 in 1918 during the last World War..

Jan 1, 1944

The State Mining Experiment Station, Missouri School of Mines and Metallurgy, Rolla, Mo Charles H. Fulton, Director of the School of Mines Martin H. Thornberry, Director of the Mining Experiment Station. From the State Mining Experiment Station are issued all the general and technical bulletins of the School of Mines The latest bulletin containing a complete list of publications will be sent upon application to the Director of the Station Residents of the state may obtain bulletins as issued without charge, or may ask to be placed on the mailing list. Nonresidents should write to the Director for further information concerning specific bulletins. From the long list of bulletins the following have been care¬fully selected as being most likely to interest the geologist and the mining engineer. Vol 8, No. 1 (1916), Bibliography of concentrating ores by flotation, by J Cunningham, vol 1, No 3 (1912), Some apparatus and methods for demonstrating rock drilling and the loading of drill holes in tunneling, by L E Young, vol 2, No 1 (1915), Comparative tests of piston drill bits, by C R Forbes and L M Cummings; vol 2, No 3 (1916), Cupellation losses in assaying, by H. T Mann and C. Y Clayton; vol 4, No 1 (1917), The hydrometallurgy and electrolytic precipitation of zinc, by F D. James; vol 4, No 2 (1917), The effect of additional agents in flotation, pt 1, by M. H. Thornberry and H T. Mann, vol 5, No 1 (1919), The carbonization of Missouri cannel coals, by H L. Dunlap, K. K. Kershner and V. X Smiley. Vol 5, No. 4 (1921), Coal mining methods in Missouri, by W W Weigel, vol 6, No 1 (1921), The problem of the St Peter sand¬stone, by C L Dake, 50 cents, vol 6, No. 2 (1922), Bibliography on the electrothermic metallurgy of zinc, by B M. O'Harra, vol 6, No. 4 (1923), Experiments on the distillation of zinc from complex zinc-lead-silver ores, by B M. O'Harra and E S. Wheeler, vol 7, No 3 (1924), Underground loading devices, by C. E. van Barneveld, 81; vol 7, No. 4 (1924), Briquetting of zinc ores, by B. M. O'Harra; vol. 8, No 2 (1925), A treatise of Missouri clays, by M. H. Thornberry.

Jan 1, 1933

By Morris M. Fine, Norwood B. Melcher

It is out of the question, at this time, to select any one prereduction process as superior to the others. It is apparent that several share a basic similarity and that within the groups listed in Part 1, the reduction vessel is sometimes the only significant variable. Claims as to the virtues of one machine over another are difficult to substantiate: one may be rapid, another thermally frugal. Based on published data, however, all seem to be performing adequately. It would appear that processes based on carbonized pellets are most applicable to foundry iron at low production rates. Adaptation to large scale manufacture of blast furnace hot metal or to agglomeration of fine concentrates at the mine site is much less likely.

Jan 8, 1966

By D. I. Bardos

The occurrence of Laves phases (AB,) in various binary alloy systems has been reviewed in recent papers.13 Iron forms Laves phases with Sc-, Ti-, V- and Cr-group elements. However, two of the corresponding Laves phases with cobalt, namely MoCo, and WCo,, are missing. Nickel forms binary Laves phases with Sc and Y, but not with any Ti-, V-, or Cr-group element. These conditions are schematically illustrated in Table I. That electron concentration is a significant factor in determining which type of Laves phase is formed in a given case was recognized long ago by Laves and Witte,4 This concept has been more recently applied to Laves phases formed by transition ele-ments. It now appears that the average electron concentration (average number of electrons per atom outside of the closed shells of the component atoms) may be an important factor also in determining whether or not a Laves phase can occur at all in a given system. As shown in Table I, in the transition element systems considered Laves phases are absent at electron concentrations of 8, or larger (to the right and below the double line in Table I). These absences clearly cannot be accounted for on atomic size considerations, as evidenced by the many inconsistencies apparent in Table 11. While the ideal radius ratio for Laves phases is 1.222, in the systems which do have Laves phases the ratios of CN 12 radii range from 1.10 to 1.46. The consistent absence of Laves phases at RA/RB< 1.10 might be attributed to the low values of these radius ratios. However, Table II shows that absences also occur irregularly throughout the radius ratio range covered. In a previous paper7 it was concluded that, in transition element systems forming u-phases, silicon may act as an acceptor of electrons, thus stabilizing the u-phase at electron concentrations higher than

Jan 1, 1962

By George H. Jones

NO STRANGER phenomenon exists in the American mining industry today than the so-called bootleg anthracite industry in Pennsylvania which now produces probably close to 15 per cent of the total hard coal out- put of the State. Instead of being what - was first thought to be a temporary condition, countenanced because of the desperate condition of some of the miners at the depth of the depression. it is thriving now as never before. Re- ports of it have penetrated all over the world, as exemplified by inquiries concerning it in Durban, South Africa mentioned by John C. Cosgrove in his article in the July MINING AND META LURGY.

Jan 1, 1939