Search Documents

By Andrew Hyslop

IN our never ending search for new and better ways of underground mining, we find that transportation has had its share of new ideas in the past few years. The old and still effective method of track haulage has had some competition from rubber tired cars and belt conveyors, each of which has its own safety hazards which demand close scrutiny in any safety study. The use of shuttle cars, in particular, has introduced clearance hazards caused by the absence of the more or less positive guides formed by the rails of a track sys¬tem; likewise the requirement of greater clearance tends to increase roof hazards which we all know to be great enough with the best of methods. However, the subject of transportation hazards is too broad to be covered entirely in one paper, so I will confine myself to track methods which carry the preponderance of underground tonnage. I am quite sure that to this group it is an evident fact that haulage accidents are of major importance. However, to stress the point, it may be well to look at a few figures. Safety statistics can be quite boring and often are subject to question as to mathematical accuracy because of different

Jan 1, 1948

L. C. UREn,* BerkelEy, Cal. (written discussion).—I heartily concur with Rlr. .Fobs concerning the need for advanced courses on various phases of Petroleum Engineering. I think that his criticism is probably true of most of the engineering schools that are specializing at all in Petroleum Engineering, that is, that most of their so-called graduate courses are not of graduate caliber but are merely more specialized aspects of undergraduate subjects. It would undoubtedly be to the advantage of the petroleum profession if more advanced work could be offered in a few of the leading engineering institutions so that there would be something substantial to offer graduate students wishing to return after a period of undergraduate work, for additional training. There is no doubt but that a better trained engineer, more useful to the oil industry, could be secured from schools offering such advanced training. The problem of adpting our instruction to fit the needs of engineers trained along other lines who wish, after completion of their undergraduate work, to enter thc petroleum engineering field, is a more difficult one. It has been my experience that such men are usually sadly deficient along certain lines and that they are really not prepared for the more advanced work in Petroleum Production Engineering until they have gone back over the work which they have missed in their undergraduate training. I note that Mr. Fohs suggests that other eastern and western colleges not now stressing Petrolelim Engineering, should be encouraged to take up advanced work of this character. With this, however, I cannot agree unless the institutions arc also prepared to offer a full sequence of undergraduate work on which the more advanced courses may be superimposed. Whether or not there is a need for additional engi-ncering colleges entering the petroleum engineering field is an open qucstion. I believe that we arc turning out enough petroleum engineers at the present time and that none of the six institutions now specializing in this field arc overcrowded. Morc-ovcr, they are fairly well distributed over the country, though there may be room for an additional school in the field in the eastcrn section of the United States. F. W. Padgett, Norman, Okla. (written tliscussion).—Assuming that the stnclcnt has the proper fundamentals, that is, general science and a knowledge of the technology of the industry, then the problem is: What courses should be offered from the graduate standpoint? (a) Course Work.—His knowledge of the technology of the industry can be extended advantagcously by means of one and two-hour courses, which consist in a more detailed survey of the various branches of the industry. (b) Lilerdure.—This work may, or may not, be connected directly with his research problem. The student should become familiar with methods of locating articles in the 1iterature; should also become familiar with all the important original

Jan 1, 1928

By H. G. Sell, G. W. King

An investigation was made of the lensile proper-ties of recrystallized high-purity tungsten and a W-1 pel ThO2 dispersed-phase alloy over the temperature region of 800° to 2400°C. The thoria addition resulted in a modest strengthening effect over the entire temperature region. A decrease in ductility of both materials occurred above 0.5 Tm which was caused by void formation. Current theories of IT has long been recognized that a second phase of hard particles has a strengthening effect on a pure metal. At low or intermediate temperatures (<0.5 Tm), the strengthening effect is thought to arise mainly from the interaction of dislocations with dispersed particles. Above 0.5 Tm, dynamic recovery processes greatly alter the deformation mechanisms from those simply involving glide, and grain bound- strengthening by a dispersed second phase do not adequately explain the tensile results. Melallographic examination suggests that the improved strength of tire alloy results from the effect of thoria on the mierostructure. Stress-dependent thermally activated processes were found to occur high temperatures. aries may act as sources of weakness rather than strength because of grain boundary sliding. Grain boundary sliding at high temperatures has been postulated to be the primary factor giving rise to the formation of voids or cavities at grain boundaries1-3 which in turn cause premature failure and poor ductility.4 Voids, once formed, can grow by the condensation of vacancies from the equilibrium concentration&apos; or from the excess vacancies produced by the deformation.4,5 The high-temperature tensile properties of unalloyed tungsten have previously been investigated by Sikora and Ha116 and also by Taylor and Boone.7 The purpose of the present work was to investigate

Jan 1, 1965

By G. W. Brock

Experiments in the form of aging of overstrained tension specimens and elevated temperature tension testing, have been carried out on recrystallized arc-cast molybdenum. The aging behavior of molybdenum was found to be strongly dependent on the degree of plastic strain present in the lattice: the reason for this being the low solid solubility for the common interstitial elements in molybdenum. GEORGE W. BROCK, formerly Research Associate, Department of Theoretical and Applied Mechanics, University of Illinois, Urbana, III., is Research Associate, Department of Engineering Sciences, IBM Research Center, Yorktown Heights, N. Y. Manuscript submitted January 19, 1961. IMD THE term strain aging is familiar in connection with the recovery of the yield point in mild steel after tensile overstraining, and there are other instances where it is known to exert an appreciable effect on mechanical properties. For example, steel exhibits a greater tensile strength at mildly elevated temperatures than at room temperature and serrated stress-strain flow curves occur under certain conditions. It has been known for a number of years that the phenomenon of strain aging is directly connected with the presence of carbon and nitrogen in the lattice; and extremely small amounts of either element are sufficient to produce the effect. In this study, the aging behavior of overstrained tensile specimens of recrystallized molybdenum has

Jan 1, 1962

By C. Stansfield Hitchen

THE introduction of the logarithmic sector method of quantitative spectrography by Scheibe and Neuhäusser in 1928, and the subsequent .modification and improvement of the method by Twyman and Simeon, would seem to have marked yet a further advance in quantitative spec-trum analysis and its industrial application, inasmuch as it offers a simple means of eliminating some of the uncertainties inherent in the older methods based upon mere visual comparison of line intensities. In their recent admirable review of the position and capabilities of industrial spectroscopy, Brownsdon and van Someren1 say: Ways and means of facilitating the comparison of line-intensities so as to give them numerical values are helpful, and of these a logarithmic sector rotating in front of the slit appears to he one of the most promising; . . . the success recently experienced by the author in using this method for the examination of steels and solutions of metallic salts prompted him ,to investigate its possible use in estimating the impurities commonly present in crude and refined tin. The results of this investigation are submitted in the present paper. Details of a number of spectrographic analyses of tin for various impurities have already been published. Thus, Schweitzer2 describes the spectrographic examination of tin for lead, bismuth and cadmium, and was able to distinguish between such atomic percentages as 0.01, 0.05, 0.10, 0.30, 0.60, 1.20, 3.00 and 10.00. Negresco3 investigated the bismuth content of tin over a range of from 0.0005 to 35 per cent. Meggers, Kiess and Stimson4 compare spectrographic and chemical analyses of tin metal for copper, lead, iron, zinc, silver, nickel and bismuth. They stress also the value of spectrum analysis in the examination of tin used for boiler plugs, where the requirements that only minute quantities of impurities shall be present render the chemical analysis both tedious and difficult.

Jan 1, 1933

THE. extraordinary volume of work done in this period, and the multiplicity of subject matter, make a year-by-year historical account undesirable, if the account is not to be an assembly of unrelated fragments. We shall, instead, undertake to narrate the development in this period of each of the branches of the subject separately, hoping that their interrelations will be self-evident. There is a certain arbitrariness in the selection of subject matter in the following sections. The development of important engineering alloys-for example, high-speed steel-is disregarded, for it is the primary purpose of this account to relate the advances in ideas, the growth of the science of metals; other historical accounts relate these parallel advances. Nor are advances in techniques stressed, though occasionally the most important are noted; nor is the progress described in allied fields such as welding, cutting, etc.; for though these developments have very frequently made possible the advances herein related, they are far too numerous to recount in anything short of a ponderous volume. There is a more serious arbitrariness, however; it is not an easy matter to draw the boundaries of physical metallurgy, and some contiguous subjects have been omitted that perhaps should have been included, such as, for example, corrosion, gases in metals, the magnetic behavior of metals and alloys, and certain other fields in the physics of metals. REACTIONS IN ALLOYS--DIFFUSION Many of the reactions occurring in alloys proceed by the operation of the process of diffusion in the solid state: the annealing of mixed powders to form alloys, the homogenization of castings or forgings, the freezing of alloys, the treatment of clad metals, the loss

Jan 1, 1948

By C. W. Dunham

DESIGN of the structures for the Morenci Reduction Works involved many interesting problems. Naturally, the chief purpose of these structures is to house and support the equipment and other things necessary for or incidental to the conduct of production. hence most of the features of the design were developed to suit these particular conditions; however, several are so generally applicable as to warrant description.

Jan 1, 1942

By George H. West, Ross Cummings, L. V. Steck, B. P. Little, Robert D. Pike

The drilling of constantly deeper oil wells has made it imperative that the manufacturer of casing be ever searching for new methods and new materials to meet the increased demands. One phase of this search constitutes the subject matter of the present paper. Starting from the original Drake well in 1859, the depth of wells has advanced by leaps and bounds, until today depths of 6000 to 8000 ft. are common. Conditions point to the necessity for drilling to greater depths, and it is not at all improbable that much of the future oil produc- tion will be from wells around 10,000 ft. deep. The trend to deeper wells is nicely illustrated by the curve in Fig. 1.l The points plotted are the maximum depths attained in the various pools which were at their peak for the years given. It may be of some interest to observe the change that has taken place in the tensile and collapsing stresses over the last 25 years. The pressure at the bottom of a 900-ft. hole, equivalent to the pressure caused by an equal column of water, is only 450 1b. per sq. in. The equivalent water pressure corresponding to the depth of the deepest hole today would be 4762 1b. per sq, inch.

Jan 1, 1930

By H. E. McKinstry

MOVEMENT on a fracture of irregular shape can cause local widening of the fissure and thereby offer freer channelways for circulation of ore-depositing solutions. This influence, coupled with large areas of wall rock available for reacting with ore solutions in brecciated and shattered ground can account for locally active deposition of metals and the resulting ore shoots. Such irregularities in the fracture system may be caused by local variations in the strength of rocks and by pre-existing lines of weakness, especially if these stand at favorable angles to certain components of the fracturing stress. Therefore correct interpretation of the mechanics of fracturing should permit deductions as to structurally favorable places on unexplored portions of the vein system. INTRODUCTION IT has long been recognized that movement on a curved or irregular fault surface is capable of separating the walls in certain portions of the fault, but until very recent years the importance of this mechanism as a factor in localizing ore shoots has escaped proper recognition. A short time ago W. H. Newhouse&apos; presented a careful analytical study of displacements and their corresponding open spaces. For reasons that will be discussed later, it frequently happens that portions of the vein which are favorably oriented are not merely wider but also richer than the average. In many cases the widening with its accompanying richness coincides with very minor changes in the dip or strike of the vein, irregularities that commonly escape notice unless the vein is mapped in detail and a careful geometrical analysis made. While the relationship between the width of the vein and the changes in dip or strike has been recognized as a matter of observation, the irregularities have been accepted as more or less the result of accident. There has been very little effort except in isolated cases to find out the causes of these changes in dip or strike. Yet it is clear that if the causes can be recognized and expressed in terms of geologic structure the geologist will know where to look for repetitions of these favorable conditions either on extensions of the same vein or on adjoining veins. Any lack of understanding of the causes is due to the limitations of our ability to interpret our observations and not to the sheer capriciousness of

Jan 1, 1941

By Robert C. Linares

Cubic zinc sulfide has been grown from molten salt solutions substantially below the hexagonal-cubic phase transition of 1020°C. Crystals free of birefringence have been grown from molten lead chloride at temperatures from 500° to 800°C. Factors affecting the optical transmission and the birefringence are discussed. CUBIC zinc sulfide is of interest for electrooptic devices and as an optical coating material. However, it cannot readily be produced as large crystals which are free of birefringence. The birefringence arises from the fact that the cubic ZnS is usually grown as the high-temperature hexagonal phase and is transformed to the lower cubic phase by annealing.&apos; This results in stacking faults, stress, and birefringence. A requirement for the growth of cubic ZnS is that it be grown below the phase transition of 1020°C.2 Crystals of cubic ZnS have been grown below 1020°C by the hydrothermal,3 flux,4 and vapor transport5 techniques. However, these all appear to have limitations in size or quality of material produced. It was felt that a new flux method might have a good chance of overcoming some of the previous problems. Mita6 reported the growth of hexagonal ZnS from molten NaCl and wilke7 reported the growth of iron sulfides from molten lead chloride solution, indicating that molten chlorides make good solvents for sulfides. An investigation of a number of possible molten chlorides as solvents showed that molten PbCl2 has an appreciable solubility for zinc sulfide and that crystals can be grown at temperatures from 500° to 800°C. EXPERIMENTAL Crystal growth was performed in open or sealed Vycor or fused silica tubes, in an argon atmosphere or vacuum. There were no deleterious effects due to using vacuum; however, a sealed essentially isothermal system must be used to prevent vapor transport mechanisms from dominating. This will be discussed later in detail. Noble metal containers were not usable as they were severely attacked by these melts. The materials used were: reagent-grade PbC12, reagent-grade ZnS, optical-coating-grade ZnS, and Irtran 2 (ZnS). Crystal growth was accomplished by both slow cooling techniques and gradient growth techniques. In the slow cooling techniques, 15 g of ZnS and 100 g of PbCl2 were used. The components were placed in the silica tube, heated at 800°C for 2 hr, and then slowly cooled (l° to 10° C per hr) to 500°C. The furnace was constructed so that the tube could be inverted, thus allowing the liquid to drain off the crystals at the end of the run. The gradient runs were made by placing the above mixtures in a silica tube at 550° to 600°c, Fig. 1. A temperature gradient was maintained such that the floating mass of undissolved sulfide was 10° to 50°C warmer than the bottom of the tube. Growth occurred on spontaneously nucleated sites at the cooler bottom. RESULTS When using high cooling rates (5° to 10°C per hr), crystals form in thin sheets perpendicular to the {111} face. Crystals 5 by 5 by 1.2 mm, Fig. 2, have been ob-

Jan 1, 1969

By Andrew Fletcher

AS good health is the most important asset in life, the development of healthful conditions should be the one common meeting ground of agreement between management and labor. Health should not be a subject to be pulled apart, shoved around, or bargained about. Differences of opinion may exist in the procedure and techniques employed in approaching the goal of maintaining the health of workmen, and in the method of increasing the ultimate profit of the employer by improved working and living conditions. Such matters are doubtless appropriate subjects for discussions between the interested parties, but techniques are only tools. If an employer fails to remedy a hazard or a menace which contributes to poor working condlions, this constitutes a legitimate grievance. It should not be necessary, however, nor is it desirable that fundamentals of health maintenance become matters of collective bargaining, any more than should the principles of management and engineering. I have been especially concerned during the last few months with the propaganda in collective bargaining negotiations throughout the country for including in union contracts a given number of days of sick leave with pay. We all

Jan 1, 1946

By AIME AIME

COAL occupied a large place in the technical sessions of the Institute at its annual meeting for in addition to three sessions specifically de- voted to coal the two sessions on mine ventilation and the two on ground movement and subsidence, which are reported under their own headings, were primarily concerned with coal. The first session on coal was a joint one with the Iron and Steel Division, on Wednesday afternoon, with F. H. Crockard and J. R. Campbell presiding as joint chairmen and the latter actually officiating. The principal topic of discussion was G. S. Scott&apos;s paper "Evaluation of Coal for the Making of Blast- Furnace Coke," which has been published as T. P. 159. The author made a brief statement of its con- tents to start the discussion and the chairman, after briefly reviewing it himself, called on C. A. Meissner to start the discussion. He briefly reviewed the economic factors in the use of coal for coke-making, saying that not only .does the removal of 1 per cent of ash from the coal reduce the cost of pig iron 12 or 13c. per ton, but it also permits coke of satisfactory structures to be made from a coal which otherwise could not be used. He stressed the importance of uniformity in blast-furnace fuel and discussed the benefit of mixing different coals as raw material for the coke oven and cited experience with Illinois coals.

Jan 1, 1929

By N. J. Sather

A detailed description is given of Bunker Hill&apos;s concentration process employed at the company&apos;s lead-zinc property in the Coeur d&apos;Alene district, Idaho. The plant is equipped to process 3000 tpd of Pb-Zn ore. The history of the Bunker Hill mine dates back to Aug. 26, 1885, when Noah S. Kellogg found the outcrop of the Bunker Hill orebody on the hillside of Milo Gulch above the present town of Wardner, Idaho. A small concentrator was erected in 1886, and before the railroad came, the mine output was transported by mule teams to the head of navigation on Coeur d&apos;Alene Lake. After ten years of production, an interest was purchased in the Tacoma smelter at Tacoma, Wash., to which the entire output was shipped. In 1916 and 1917, a modern lead smelting plant and refinery was erected, and a modern electrolytic zinc reduction plant was built in 1927-1928 by the Sullivan Mining Co. which was 50 pct owned (and now totally owned) by the Bunker Hill Co. The first concentrator, a 100-tpd capacity plant, was built in 1886 near the Reed Tunnel in Wardner. The treatment consisted simply of crushing ore to 2 in. and then to 1/2 in. through rolls in closed circuit with a bucket elevator and trommel screen. The undersize was further sized in trommels to 10 mm and 3 mm. Oversize from the latter was treated in Hartz jigs. The 3 mm undersize was classified in crude hydraulic classifiers furnishing sands to sand jigs, the overflow being dewatered in a long V tank which supplied sands to a Cornish buddle and to Frue vanners. The concentrates were of excellent grade, old records showing assays of 69 pct lead and 29 oz. of silver per ton. Tailings were high inasmuch as the provision for treating the slimes was inadequate. Since the erection of the first mill, the Bunker Hill plant has gone through many changes and improvements. In succeeding years, the flowsheet was enlarged somewhat with Huntington and Chilean mills, vanners, tables, ball mills, and flotation cells being progressively added. In the transition period to the present day practice, the object was not only to improve the equipment for better mechanical performance, but to add new equipment whenever practicable so as to improve both grade and recovery of the product at a lower cost. For the modern plant and flow-sheet, see Figs. 1 and 2. The history of flotation at Bunker Hill dates back to 1913 when experimental work was done in a cell in which the pulp was circulated through a centrifugal pump set outside the cell and discharged against a baffle in the cell. The cell was built with a spitzkasten, and the quiet zone in the latter tended to let the froth break down before it got to the overflow weir. To remedy this situation, a belt drag with light metal flights was arranged for drawing off the froth over a ramp in each cell. Recovery of lead was not as high as present day practice, but was so much better than the vanners that the cells were multiplied gradually to eight cell units. The mill men called them mud hens. Flow between the cells was controlled by a weir, which determined the pulp level in each cell. These early machines were called Bunker Hill machines. The tailings were later treated in pneumatic scavenger flotation machines in a series, producing concentrates for retreatment in the Bunker Hill cleaners as well as the final tailings. This system of flotation served with minor changes until the Fahrenwald machine was developed at Bunker Hill during the period from 1921 to 1925. In 1925, the Fahrenwald flotation machine gradually replaced the Bunker Hill machine, although the Hearing pneumatic scavengers for retreatment of the tailings from the Fahrenwald machines were retained in the lead section until 1928. The use of the Hearing pneumatic machine for cleaning the rougher concentrates was begun in 1924. In 1941, plans were made for remodeling and modernizing the concentrator, the goal being a modern concentrator employing the latest equipment and milling practices. The old wooden building was to be replaced by a steel and concrete structure. Shortly after preliminary work got under way, the United States entered World War II and the demands for metals increased. To meet this requirement, the management decided to increase the capacity of the concentrator to 1800 tpd. This was accomplished in record time by the construction and operation of a sink-float plant. Installation of this plant was the first step in the general plan for modernization. In 1947 the concentrator (including the sink-float plant) was enlarged to handle 3000 tpd. Milling operations today are at the rate of 2300 tpd, five days per week. During 1959, 453,000 tons of ore was beneficiated. The Bunker Hill concentrator is in three sections: the crushing plant, a 3000-ton capacity storage bin, and the concentrator building. The crushing plant is of wood design with a gunnite coating on the exterior.

Jan 1, 1961

By W. Joseph Schlitt, William D. Southard, Bruce P. Ream, Lawrence J. Haug

The operation of Kennecott&apos;s Bingham Canyon copper precipitation plant, one of the world&apos;s largest, is described. This description includes a brief historical review of precipitation at Bingham and the general layout and operation of the present cone cementation facility. Current practices are based on results of studies undertaken to define improvements needed in each unit operation. These improvements were required to meet changing plant conditions and were implemented primarily within the constraints of the existing facilities. Specific unit operations included were the cone precipitators, the cone discharge thickener, the cone effluent settling basins, and the plate and frame filter presses. As a result of these improvements, loss of precipitated copper decreased and the degree of precipitation increased, raising copper recovery by 9 t/d. At the same time, iron consumption was reduced by 22.5 t/d. Problems in drying the cement copper were also overcome so that a product containing 12 - 15% moisture could be consistently delivered for smelting.

Jan 6, 1979

By William D. Southard, Joseph W. Schlitt, Bruce P. Ream, Lawrence J. Haug

The operation of Kennecott &apos;s Bingham Canyon copper precipitation plant, one of the world&apos;s largest, is described. This description includes a brief historical review of precipitation at Bingham and the general layout and operation of the present cone cementation facility. Current practices are based on results of studies undertaken to define improvements needed in each unit operation. These improvements were required to meet changing plant conditions and were implemented primarily within the constraints of the existing facilities. Specific unit operations included were the cone precipitators, the cone discharge thickener, the cone effluent settling basins, and the plate and frame filter presses. As a result of these improvements, loss of precipitated copper decreased and the degree of precipitation increased, raising copper recovery by 9 t/d. At the same time, iron consumption was reduced by 22.5 t/d. Problems in drying the cement copper were also overcome so that a product containing 12-15% moisture could be consistently delivered for smelting.

Jan 1, 1980

By L. C. Kern

This paper presents information on the use of a new propping agent (malleable aluminum particles) which has been used successfully for producing high-conductivity fractures. The conductivity of a packed fracture depends on the width of the fracture as well as the permeability of the propping material. It is significant that the flow capacity of a propped crack is often increased many fold by propping the crack with a sparse distribution of particles. However, the flow capacity of a sparsely propped crack can be limited by two phenomena: (I) crushing of the propping particles, and (2) embedment of the propping particles in the formation walls. Malleable aluminum particles exhibit interesting properties which tend to overcome these limitations. As high loads are applied to the particles they will deform slightly, rather than shattering. The deformation results in a greater bearing area against the formation wall. This reduces the stress on the particle and reduces particle penetration into the formation. The behavior of aluminum particles under load and the bearing capacities of serveral formation rocks have been measured in the laboratory. By properly using these data, as explained in this paper, the flow capacities of aluminum-propped cracks can be calculated for a variety of conditions. Aluminum particles have been used successfully in the field to prop fractures. Where high-conductivity fractures were needed, the aluminum-propped fractures have given greater well stimulation than could have been expected for conventional fracturing processes. INTRODUCTION The purpose of a hydraulic fracture treatment is to create a conductive channel from the wellbore out into the oil or gas formation. The word conductive is emphasized because we believe that the fracture conductivity (flow capacity) is one of the most important factors influencing fracturing results. Previous papers have pointed out the additional well stimulation that can sometimes be achieved by increasing fracture conductivity. Several years ago, we investigated in some detail the effect of fracture conductivity on productivity increases to be expeced from vertical fractures. Both electrical analog and theoretical studies of unsteady-state flow behavior were made. A discussion of the electrical analog equipment and some of the results of the study were given in a previous paper&apos; by Dyes, Kemp and Caudle. Further details were given recently by McGuire and Sikora.5 Fig. 1 shows the remarkable influence of relative fracture flow capacity and length on well stimulation. Briefly, the study indicates the following. 1. High-permeability formations require high-conductivity cracks for best results. 2. The longer the crack, the higher the fracture conductivity required for best results. 3. If the conductivity of the crack is very large compared to the formation (i.e., flow is not being limited by crack conductivity), then the longer the fracture, the better will be the results. Judging from recently published articles,1,314 there is current interest in methods for obtaining high fracture conductivities. Hence, we would like to present in this paper a discussion of a new fracture propping process (use of aluminum particle) which we have used successfully to obtain highly conductive fractures. There are several factors which influence the conductivity of a propped crack. Conventional fracturing techniques frequently result in a crack completely packed with fracturing sand. For such conditions, the crack conductivity is the product of the width of the packed fracture and the permeability of the propping material. It is significant that a large increase in conductivity sometimes can be obtained by propping with particles which are distributed sparsely (less than a

Prof. Mathesius analyzes the running of Howland&apos;s furnace No. 19, according to the method described by him in Stahl and Eisen, 1916, Nos. 30 and, 31, and in his work "Die physikalischen und chemischen Grundlagen den Eisenhüttenwesens" (Spamer, Leipzig). By assuming 500 Cal. lost from the hearth by radiation and cooling water per kilogram of pig iron made, a throat-gas temperature of 600° C., and taking the ratio of C02/CO as 0.64, he finds that his diagram would show 0.68 kg. of carbon oxidized per kilogram of pig iron, while Howland gives 0.66 kg. He expresses himself as well satisfied with this test of the accuracy of his theory. Making the further assumption that the heat losses from the shaft are 1,000 Cal. per kilogram of pig iron (twice as

Jan 5, 1917

By Walter S. McKee

When mixed with common cast steel in quantities ranging from 11 to 131/2 per cent. and properly treated, manganese increases the ductility of the metal and adds greatly to its toughness and resistance to abrasive action, which properties comprise the distinctive characteristics that make manganese steel so valuable for many purposes at the present time.. * At present the manganese-steel foundries of this country have an annual capacity of about 60,000 tons and most of the growth has occurred within the past 10 years. In the early days of the industry it was impracticable to make manganese castings weighing over a few thousand pounds, but at present crusher heads, rolling-mill pinions, and similar castings weighing up to 30,000 Ib. each are produced, and it does not appear that the limit of weight has been reached by a considerable margin. Manganese steel is similar in analysis to ordinary first-class converter metal except that it is high in carbon and contains from 11 to 13.5 per cent. of manganese. From one standpoint manganese steel is similar to malleable iron in that the casting as it comes out of the sand is hard and brittle and must be made ductile by a heat-treating process. The heat treatment is an essential part of the process of making manganese-steel castings and must be properly carried out to secure satisfactory results. The necessity for heat treatment limits the thickness of sections which may be made of manganese steel. Originally the annealing depth was comparatively small, but researches carried on during the past few years have resulted in an increase in the thickness of section up to 51/2 in., which it is possible to treat successfully. Large castings are cored out to a minimum thickness of 51/2 in., thus not only eliminating some of the internal stresses which are invariably set up in a very thick casting, but also reducing the weight and inertia of the piece, an important consideration if the casting is to be a moving part in a machine. At the same time, the thickness of 51/2 in. is sufficient to permit the use of manganese steel for the heaviest classes of machinery.

Jan 1, 1916

By William E. Ford, Edward Salisbury Dana

The Silicates are m part strictly anhydrous, in part hydrous, as the zeolites and the amorphous clays, etc. Furthermore, a large number of the silicates yield more or less water upon ignition, and in many cases it is known that they are, therefore, to be regarded as basic (or acid) silicates. The line, however, between the strictly anhydrous and hydrous silicates cannot be sharply drawn, since with many species which yield water upon ignition the part played by the elements forming the water is as yet uncertain. Furthermore, in the cases of several groups, the strict arrangement must be deviated from, since the relation of the species is best exhibited by introducing the related hydrous species immediately after the others. This chapter closes with a section including the Titanates, Silico-titanates, Titano-niobates, etc., which connect the Silicates with the Niobates and Tantalates. Some Titanates have already been included among the Oxides.

Jan 1, 1922

By F. G. Smith

A FEW years ago, the writer encountered a, problem that, at first, seemed to be due to peculiar conditions affecting grain growth. Large cups made from heavy metal failed in the first drawing operation in the process of making seamless tubes. The metal, as cast, appeared to be sound and strong; it rolled successfully and withstood the first cupping operation, but on the first draw it failed, with a crystalline fracture. The failure appeared in the slightly worked part of the bottom of the cup, and microscopic examination revealed exceptionally large grains. Knowing the general conditions governing recrystallization of brass, which were later published by Matthewson and Phillips, an investigation was outlined with the idea of including various conditions under which new grains might form, and which would include the effect that a previous anneal might have upon the anneal following. These conditions were produced by annealing specimens of brass at five different temperatures, indenting them with a 10-inn. ball under four different pressures, and then reannealing at each of the five temperatures five specimens each of which had been annealed at one of the five temperatures.

Jan 8, 1919