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By C. H. Li, S. H. Bendel, J. A. Sartell

Small additions of Mg to a 62 Cu-38 Ni alloy reduce the oxidation yates drastically between 500° and 850°C. Metallographic examination of the oxide scale disclosed a continuous network, identified by X-ray diffraction as (Ni, Mg)O solid solutions, located along the former alloy grain boundaries. This network acts as a barrier to diffusion. It is thought to result from the segregation of mg to the alloy grain boundaries. Oxidation occurs preferentially in these regions because of the presence of this more active element. To substantiate these ideas, homogenized alloys ulere oxidized. No oxide network was produced and oxidation rates were the same as for the parent 62 Cu-38 Ni alloy. An interesting aspect of the oxidation of the 62 Cu-38 Ni alloy previously described by the present authors, is the relationship between oxidation kinetics and changes in the microstructure of the oxide.' The oxide scale on these alloys consists of two layers: a thin layer of CuO outside a much thicker layer of Cu20 in which particles of NiO are dispersed. In addition, immediately beneath the oxide-metal interface there is an internally oxidized zone in which NiO particles are dispersed in a copper-rich alloy matrix. Experimental observations on the growth of the individual layers under isothermal conditions have led to the conclusion that the rate-determining step in the oxidation of this alloy is the diffusion of anions through the Cu20 layer. It has been found that this diffusion rate is increased by the recrystallization of the outer CuO layer. Willardson and Gorton have reported that the addition of magnesium to the 62 Cu-38 Ni alloy causes a decrease in the oxidation rate.2 The present investigation was undertaken in order to determine the mechanism by which magnesium additions improve the oxidation resistance of the 62 Cu-38 Ni alloy. EXPERIMENTAL PROCEDURE Fifty-gram ingots of Cu-Ni alloys were prepared by vacuum melting materials of 99.999+ pct purity. These ingots were then remelted in a He atmos- phere and magnesium added in the form of a previously prepared and analyzed Cu-Mg master alloy. This procedure was necessitated by the high reactivity of pure magnesium at high temperatures. The proportion of the alloying elements was adjusted so as to obtain alloys with the desired magnesium content while maintaining a Cu-Ni ratio of 62 :38 by weight. (All alloy compositions will be given in weight percent.) Since it was considered desirable to study the oxidation of only single-phase, solid-solution alloys, it was necessary first to determine the approximate limit of solid solubility of magnesium in the 62 Cu-38 Ni alloy. A series of melts with various magnesium contents was made, homogenized by annealing for 48 hr at 975OC, then cooled in the furnace. Metallographic samples were prepared, etched in a potassium dichromate solution and examined at XI500 for the presence of a second phase. The alloys were then chemically analyzed and it was found that the approximate limit of solid solubility of magnesium in the 62 Cu-38 Ni alloy was 1 pct Mg. The ingots containing less than 1 pct Mg (0.19, 0.29, 0.58, and 0.87 pct Mg) were cold-rolled down to thicknesses suitable for oxidation experiments and specimens for gravimetric studies were cut to dimensions of 3.0 by 1.5 by 0.05 cm, specimens for inert marker studies, 0.6 by 0.6 by 0.17 cm. These were heat-treated in a protective atmosphere at a temperature (975" C) well above the oxidation temperatures and furnace-cooled to insure structural stability of the alloy during oxidation. Immediately prior to oxidation, the specimens were chemically cleaned by immersion for 1 min in a solution of 2 parts nitric acid, 1 part acetic

Jan 1, 1961

By F. Lynwood Garrison

The enormous growth of the manufacture of Bessemer steel in this country within the last few years, due to the almost constant large demand for steel rails, renders it very desirable that our knowledge of the physical and chemical properties of a material upon which we place so much dependence should be increaqed by every possible means. It was with this end in view, and also in hopes of learning something of the causes affecting the regularity of the Bessemer product, that I took up the subject of this paper a short time ago. The lise of the microscope as an instrument of research in the metallurgy of iron and steel is now fairly well established;

Jan 1, 1887

By W. E. Glenn

The years immediately ahead-1961, 1962, 1963- will be critical years from every standpoint for the young engineer. In the next few years, he must learn to grow professionally. Most often, the rate and extent of this growth will be governed by his own initiative and perseverance. Habits and attitudes acquired during these early professional years relate very closely to, and even foreshadow, future accomplishments. The future goal of the young engineer is a moving target. It will change with professional growth, family requirements, changes in predominant interest, general economic and business conditions and geographic location. However ambitious and stead-fast in his goal he may be, the young engineer should not hesitate to adjust or change-for he really does not know initially what he is best fitted for and will not know until he has tried a number of things patiently and persistently.

Jan 1, 1961

By D. Hodouin, T. Gelpe

A digital simulator of classification and grinding circuits is used to evaluate the performance of various flowsheets. For a given flows he et configuration, unit process dimensions, and operating conditions, the simulator calculates the steady-state values of the process variables and determines the conditions that meet the required operation criteria for tonnage and product quality. Calculation examples are proposed for the design of wet and dry grinding circuits. The performance of different configurations of cement clinker and sulfide ore grinding flowsheets is evaluated and discussed.

Jan 1, 1986

By Clamer, G. H.

G. H. CLAMER, * PHILADELPHIA, PA.-Unfortunately, prior to the war no serious attention was given to the conservation of tin, notwithstanding that this country is practically dependent upon outside sources for its entire tin supply. Tin is of vital importance in many industries, but it is surprising how many and how excellent are its substitutes when we become acquainted with them. Tin has always been a relatively high-priced metal, and it is part of the human attitude to associate high prices with high standards; it is not until the price of a commodity becomes well-nigh prohibitive that we hunt for substitutes, because the idea of substitution seems always to involve an assumption that the substitute must necessarily be inferior. The history of the development of bearing bronzes is a striking example of this policy. In the early clays, copper-tin alloys were almost universally used, the idea then being prevalent, which is still held by many, that a bearing to resist wear must be hard, and the harder the better. The favorite bronze bearing contained 90 per cent. copper and 10 per cent. tin; frequently, in service which was considered severe, even higher proportions of tin were used.. Such hard alloys have great resistance to compression, but as a rule they had a very wide factor of safety in this

Jan 12, 1918

By J. J. Reed

The mines of southeast Missouri's Lead Belt have been in operation since 1864, almost 100 years. During this period about 10 pct of the total ore available has been left in place as pillars, and this now represents the best ore reserve left to the older mines. St. Joseph Lead Co. has been investigating various plans of pillar recovery for several years. The example to be described is only one possible approach under a specific set of conditions. Conditions vary greatly in the different areas within the Lead Belt, and the same approach would be entirely inadequate in certain other areas, but there are important sections where this system is clearly applicable. Horizon mining is practiced in the Lead Belt, and stopes may vary from 10 ft to well over 100 ft high. Fig. 1 is a plan view of 6100 stope, the area to be discussed. For these mines this is a small stope, only 10 to 12 ft high. Before any plans were drawn up for pillar recovery, three independent estimates of the pillar grades were made by the mine superintendent, the mine captain, and the mine geologist. After these results were averaged, pillars indicated to be of economic grade were marked for removal as shown. At this stage several alternatives were considered: 1) retreat with caving, 2) concrete replacement pillars, and 3) systematic bolting and retreat. A retreating system with caving was not chosen because the roof was known to be too bad even to permit loading a blasted pillar before caving would begin. Concrete replacement pillars would have been too costly and would have required a large crew, bulky materials, and unwieldy equipment. Systematic bolting was chosen as being most acceptable for the following reasons: 1) Limited area and spans were involved. 2) Only minor modifications to the jumbo would be required for bolting. 3) Only a two-man bolting crew would be needed. 4) Only compact bolting materials would be required. 5) The bolting plan could be modified to allow

Jan 1, 1960

By T. C. Rao

Oil agglomeration experiments were carried out on coal fines to study the effect of process variables such as pulp density, bridging oil dosage and intensity of agitation on (i) size distribution and (ii) yield of agglomerated product. It has been observed that the growth of agglomerates follows a self-preserving behaviour and using this, a characteristic curve has been derived. This curve has been found to be independent of the process variables. It has also been noted that the growth of agglomerates follows second order kinetics. In an attempt to model the process for predicting the size distribution and yield of agglomerates at different levels of the variables, the cumulative 50 percent of the agglomerates passing size (d50) has been correlated with the variables (i) through the kinetic equation and (ii) directly. These equations, coupled with the characteristic curve can predict the size distribution of the agglomerates at any levels of the variables tested. The yield of agglomerates has been found to follow a definite relationship with d50.

Jan 1, 1984

By J. O. Whiteley

IT is difficult to give a refining outline that may be followed for any and all combinations of the platinum metals; different combinations require different methods of attack. This paper does not pretend to go into all of the reactions of the metals of the platinum group, but will outline the commercial refining of platinum scrap. TYPICAL PLATINUM SCRAP As a concrete case, let us take 100 oz. of miscellaneous scrap, made up of jewelry scrap, dental scrap and laboratory ware. This lot will contain some platinum, palladium, iridium, ruthenium, rhodium, gold, silver and copper. The first problem is to get all of the metals in solution. If the scrap is principally platinum, palladium and gold, a treatment with aqua regia is the course to pursue; but if the scrap contains alloys high in iridium or ruthenium, aqua regia will act too slowly. In the case in hand, we are going to presume that we have scrap high in iridium and ruthenium, and proceed accordingly.

Jan 1, 1928

By Charles H. Hopkins, J. M. Lohr

A COMMERCIAL development requiring a suitable alloy or alloys for sealing into various grades of glass made it desirable to have a more exact knowledge' of the expansion characteristics of the nickel-iron alloys than appeared in the published literature. The expansion of the more common [ ] types of glass under consideration varies from 2.7 to 10.4 X 10-s per degree Centigrade, over the range 20° to 400° C. For reference, the thermal expansion curves of several types of glass used for sealing by the lamp and tube industries are given (Figs. 1 and 2). This paper covers a detailed investigation of the thermal expansion of a series of nickel-iron alloys in which the nickel content varies from 30 to 70 per cent. Particular stress is laid on the alloys that contain between 40 and 55 per cent Ni.

Jan 1, 1938

By R. A. Thomas, R. L. Solbod

The importance of transverse diffusion on the finger development in a miscible-phase displacement at an adverse mobility ratio of tbree was studied in a porous plate 1/4-in. thick, 3-in. wide and 18-in. long. Fast displacement rates (29 ft/D) and slow rates (1.6 ft/D) were used to determine the effect of residence time on the geometry of the fingers. The shape of the fingers was observed directly by use of the X-ray technique. At fast rates numerous narrow fingers were observed, but at slow rates a single somewhat bulging finger was produced. The amount of material moved transversely by diffusion across the plate was sufficient to modify the finger geometry in the slow-rate run because of the long residence time. These results are in contradiction to some of the postulates in the literature. The composition of the effluent stream, however, was not affected by the flow rate. This result is not inconsistent with the observed change in the shape of the finger in a short model, but it seems likely that a short model does not offer adequate and proper scaling of the reservoir. The model used was probably a valid one for studying the effect of transverse diffusion on the finger geometry, but a longer model would be needed for proper scaling of the effect of the change in the finger shape on the efficiency of displacement as measured by the composition of the effluent stream. INTRODUCTION Fingering can be defined as the uneven advance of the injected phase as it moves into a porous medium displacing the resident phase from the pore spaces of the rock. The use of this term is usually restticted to the situation in which the displacing phase is less viscous or more mobile than the fluid being displaced. Under these conditions, not only are fingers formed, but the length and width of the fingers grow with distance traveled in the porous medium. This subject has become one of great interest to the oil industry because of the present trend toward the use of various forms of miscible-phase displacement to increase oil recovery. Since in nearly all of the known modifications of the miscible-phase displacements an unfavorable mobility ratio exists (the displacing phase has a lower viscosity than that of the crude oil), the conditions are proper for fingering to develop. An appreciable amount of fingering appears to be a severe handicap to these processes for it increases the volume of agent required for the process to be a success, and such an increase puts a severe strain on the economics of the proposed processes. In some cases, such as for a mobility ratio of 200 unfavorable, it has already been demonstrated that the proposed process would not be economic if the fingering in the field were to be of the same magnitude as that observed in the laboratory. A number of aspects of fingering have been studied and reported in the literature. While the phenomenon of fingering cannot be regarded as a completely understood subject, considerable information exists on the effect of the path length and the mobility ratio on the growth of fingers. Less-complete data are available on the effect of the diameter of the flow path on the character and amount of the fingering, and even less agreement in results exists on the effect of rate of flow on the nature of fingering. This paper deals with one aspect of this latter subject. OBJECTIVE The objective of this study was narrowed down to one rather specific feature of the behavior of fingers in miscible-phase displacement in porous media. The variable studied was the effect of rate of flow on the nature and the development of fingers. It should be made clear at this point that, while rate was the apparent variable, the real variable was residence time; that is, at low rates the fluids are present at a given spot in the porous medium for a longer time interval than at fast rates. The purpose of the study, therefore, was to determine the changes which occur in the fingering and the possible benefits which might accrue from a longer residence time during that period when fingers are

By V. V. Strishkov, Zane E. Murphy, George Markon

Soviet industrial expansion depends on coal as a source of power and raw materials for the USSR's metallurgical and chemical industries. Knowledge of the Soviet Union's coal resources and production outlook is essential for a critical evaluation of the Soviet industrial potential. Although there is considerable literature on the Soviet coal industry, no single source provides an authoritative study of how the coal industry functions and how well it per- formed its job. Soviet reports are singularly lacking in the precise data in terms that are comprehensible to a westerner. It is essential, therefore, to clarify the terms in Soviet parlance. These terms are not comparable to those in common use in the West and are the cause of most inaccurate results. Official Soviet data on labor productivity refer to a limited group of "production workers" while in the West all wage earners are counted. Statistics are based on unprepared or run-of-mine coal, whereas it is customary elsewhere to measure productivity in terms of marketable coal. Thus, many western publications, while diligently and accurately reporting published Soviet data, overstate the case, presenting an exaggerated picture of Soviet progress in coal production and technology. (In terms of Western criteria, there is a three-fold exaggeration of labor productivity.)

Jan 5, 1973

By S. T. Sorrell

To obtain a negative determination for prime farmlands in its approved lignite surface mine permit application, Phillips Coal Co. conducted a soils mapping effort and a historic land use survey. In addressing the justification for topsoil substitute materials, the company relied on results of a geochemical evaluation to demonstrate improved drainage, trafficability, and fertility. It also relied on results of field test plots. Post-mining land use was determined through the use of overlay maps considering existing land use, vegetation, and historic prime farmland. The reclamation plan incorporated these elements plus indicator species, existing vegetation, and wildlife needs.

Jan 1, 1985

By L. C. Snider

All important industries have certain basic principles in common which govern them and give them a family resemblance. In addition, each industry has a certain individuality due to some principle or principles which govern, or are accepted as governing, that industry and which is not effective in others. The customs and practices of an industry depend on these basic principles much as the corollaries follow a proposition in geometry. After the proposition is proved or is accepted as proved, the corollaries are seen to be true almost without additional evidence or proof. In many cases, the corollaries are more important in practical affairs than the proposition on which they depend. By continued application the corollaries may come to be accepted as law and the fact that their truth depends on the correctness of the fundamental proposition is forgotten or ignored. If it is discovered that an error was made in demonstrating the proposition and that the proposition is untrue, the corollaries are, in most cases at least, equally untrue. Considerable time may be required, however, to realize the fact that the corollaries have failed, particularly if they have been embodied in custom and law. For example, in the business of government the proposition that women are intellectually inferior to men was formerly considered, by most men at least, to be duly proved if not axiomatic. This propositiot was never embodied in law, but its corollaries—that the rights of the wife in property and even in her own children were inferior to the rights of the husband, and that women had no place in governmental affairs—were duly incorporated in law or so completely approved by custom that they had the effect of law. Developments of the past few decades have proved, to the satisfaction of the majority, that woman's intellectual inferiority to man had not been satisfactorily demonstrated, and that the proposition that she was inferior, although accepted for many generations, was untrue. It was not so great a shock to men to discover that this proposition was wrong as it was to find out that its corollaries were also untrue and that the laws embodying them were not good laws and were subject to repeal. The adjustments which give women equal rights with men

Jan 1, 1932

No. 576.-Graduate mining engineer, married, 32 years of age. Have had 10 years' experience in mining from position of mucker to that of general superintendent. For past four years have been in Copper River District of Alaska as mining engineer, and superintendent of gold and copper mines. Desire position in U. S. Best of reference. No. 577.-Member, technical, age 27, married. Open for engagement. Past year in war mineral field work, operation and production. Ten years thorough experience in both subordinate and executive positions, gold, silver and copper in the U. S., Mexico and South America. Devel-

Jan 5, 1919

By L. W. Eastwood

PART 1. EFFECT OF HEATING RATE UPON RECRYSTALLIZED GRAIN SIZE OF ALUMINUM AND ALUMINUM ALLOYS AMONG those concerned with the annealing and heat-treating of aluminum and aluminum alloys, it is well known that after cold-working a coarser grain is usually produced by slow heating than by more rapid heating. Consequently, for the control of the grain size produced by annealing or heat-treating cold-worked aluminum and aluminum alloys, the heating rate is of considerable practical importance. References in the current literature on the effect of heating rate are numerous, but it appears neither necessary nor desirable to give here a review of the former work done on this subject. It became evident during some preliminary work on the recrystalliza-tion of aluminum and aluminum alloys that the effect of heating rate depended upon the type of microstructure of the metal. This observation led to the following study of the relationship of the type of microstructure of the alloy to the effect of the heating rate.

Jan 1, 1939

Draftsman and transitman for coal mine work in Middle West. Salary $125 per month. No. 277. Men capable of taking charge and superintending the construction of plants. No. 331. Position for mining engineer in district with two large operating mines, four mines under development, and two mines temporarily closed, because of water conditions. Another assistant is desired. Excellent school facilities in model town; house available for engineer. Would consider recent graduates. No. 332. Engineer or firm of engineers competent to survey and estimate the extent and the contents of a deposit of clay in the southern -mountains of Pennsylvania, and to figure on the cost of getting the material, presumably through a tunnel running into the side of the hill on which the property is located, as this is the method by which similar properties in the vicinity are being worked. Prefer to have some one who would bid on the actual work of opening up the deposit. No. 333. Four assistant division foremen. These men must be Americans who can talk Spanish, and must be good miners and familiar with handling large stopes by the cut-and-fill, square-set and top-slice methods. Salary $200 gold per month. No. 334.

Jan 8, 1918

By Howard M. Graff, Sidney C. Bouwer

The economics of mining has traditionally been viewed quite apart from the economics of blast furnace operations. It was realized, of course, that blast furnaces would operate best with good raw materials, but the shipping grade of ore, for example, was decided by a sort of collective bargaining process between the ore producers and the blast furnace operators. The mine operators had to keep their costs down, and were usually successful in convincing management that the ore in any particular deposit was endowed by nature with a certain iron content and that the mine grade could not be raised beyond a certain economic limit. The blast furnace operators would have liked a better grade, but as long as they were able to make a fairly good showing it was more or less accepted that they had to take the ore as it came. The mine operators were able to ship to the nation's blast furnaces thousands of tons of iron ore that would be completely unacceptable by present-day standards. As late as the early 1950's, the major steel companies were witnessing an actual decline in the iron content of their incoming ore supply as the mining companies mined progressively leaner material and upgraded it only enough to pass competitive market requirements

Jan 8, 1965

By David R. Maneval

At the turn of the century, 90% of the energy output in the United States was generated by coal, and Pennsylvania was the ranking producer of this fuel. With the huge resources of easily accessible coal found by its early settlers, the Commonwealth was the nation's chief powerhouse for nearly 100 years. In 1928 alone, Pennsylvania mined a billion dollars' worth of coal-or enough to fill a train reaching more than twice around the world at the State's latitude. Coal constituted nearly 67% of the freight of Pennsylvania and was responsible for the State's $4-billion iron and steel industry. Pennsylvania was slow to take up its position as the greatest coal-producing state in the union, but the knowledge of its coal assets was not slow in accumulating. In fact, long before the white man arrived, the Indians were aware that many of the hills were underlain by black stones that would burn. But awareness was not enough. The early Pennsylvania settlers confined themselves to the southeastern corner of the State and had little need or concern for resources further inland.

Jan 1, 1971

By Harold M. Mooney

RESISTIVITY measurements for determining depth to bedrock, water table, and other geo- logic discontinuities have had only limited success. Many of the difficulties can be attributed to complex geology and to basic limitations of the method; current flow through a continuous medium is a diffusion phenomenon, emphasizing irregularities near the source and smoothing out those at a distance. Some of the failures, however, are due to careless field work and incompetent interpretation. A forthcoming publication1 may help to reduce difficulties of this sort. The writer here attempts to bring order into the multiplicity of interpretation methods and, to a limited extent, to evaluate them. For all methods, the field data to be interpreted consist of apparent resistivity values plotted against electrode separation, Fig. 1. The interpretation should give depths to one or more geologic horizons. Direct currents and the Werner four-electrode configuration will be assumed, since these are widely used, although the interpretation problems remain essentially the same for other electrode configurations. Alternating currents higher than, say, 20 cycles per second introduce complications beyond the scope of this paper.

Jan 9, 1954

By R. H. Foley

It is difficult to consider any seam as unsuitable for longwall mining operation for something like 95% of British coal is produced by this system. The following is a brief report on how they do it-their techniques and equipment. Depth of working in British mines varies from about 150 ft to more than 3000 ft, with the average being about 1300 ft. Average seam thickness is approximately 40 in., but working seams vary from 16 in. to as much as 14 ft.

Jan 8, 1965