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By John H. Bell

R. B. T. KILIANI, New York, N. Y.-I wish to present some figures based upon actual observation extending over a few months time which seem to prove the author's conclusions. It is a comparison of two machines operating on the same ore, in the same plant, one taking the undersize of ½ -in. screen and the other taking the undersize of 8-mesh. Each of the machines was first operated as a pebble mill, with flint pebbles, in open circuit, then with metal pebbles in open circuit and, finally with metal pebbles in closed circuit. For the first case, the percentage of oversize on 48-mesh, Tyler screen, in the discharge, varied, in the mill taking ½ -in- feed, from 37.2 to 19.9 per cent. The second mill, taking the 8-mesh feed, had a variation in oversize on 48-mesh, from 36.8 per cent: to 0.5 per cent.; so it is seen there is considerable variation in these figures. I have computed the tons per kilowatt-day reduced through 48-mesh for each machine under each one of these conditions, giving 6 sets of figures. The first of these I called 1.0 and determined the ratio of the others to this.. In the snipe way, I figured the relative mechanical efficiency according to Kick's law, using' the figures given by Mr. Taggart in his paper, for ordinal numbers of the Tyler screens. I have also figured the efficiency in mesh-tons per horsepower according to Gates' method by plotting the screen analyses of feed and product and multiplying the area by a constant dependent on the scale used. The commercial efficiency of tons per kilowatt-day reduced through 48-mesh checks very closely with the efficiency by Rittinger's law, within 1 per cent. except in one case. By Kick's law, the efficiency checks fairly closely, within about 5 per cent., with the commercial efficiency of the mill grinding feed, but when we start to grind a finer, 8-mesh material, and especially grinding very fine; with a

Jan 4, 1917

By Thomas W. Gibson

THE Province of Ontario in recent years has come strongly to the front as a producer of metals, especially nickel, copper, silver, and now gold. Of the last named, the output for 1922 was in the neighborhood of $20,000,000. The law governing the mining industry in a community where such develop-ments are taking place will be of interest, therefore, in other places where mining laws are up for revision The first mining of importance done in this province was for copper on the north shore of Lake Huron, where the Bruce mines were opened in 1846. These deposits of copper sulfides, notwithstanding the remoteness from markets and the cost of transportation, were vigorously worked for 12 or 15 years and also intermittently later, but the active career of the mines came to an end in 1875. From first to last, a little less than 10,000 tons of copper was produced, valued at $3,300,000. All the product was shipped to England as dressed ore, contain-ing up to 13 per cent. of the metal. In. 1866, a rich pocket of gold was found on the Richardson farm near Madoc, Hastings County, but was not followed by further discoveries of a like kind and in time the excitement it caused died away. Rich silver ore was found in 1868 on Silver Islet in Lake Superior, a speck of land not larger than a good-sized ball-room. The assemblage of minerals here was practically the same as that at Cobalt, discovered 35 years later, namely, native silver, cobalt, nickel and arsenic; in addition, there was considerable argentite, which has always been scarce at Cobalt. In all, the silver produced amounted to about $3,500,000. The belief persisted that the deposit was not mined out, and in the summer of 1922, some rich ore was extracted from the roof, perilously near the bottom of Lake Superior.

Jan 2, 1923

E L. DEGOLYER, our new president, though a petroleum geologist by profession, has always s been associated with mining, for soon after his birth at Greensburg, Kan., on Oct. 9, 1886, his parents moved to Joplin, and when he went, in the course of time, to the University of Oklahoma, he intended to follow his course there with another at a mining school. He became a field assistant in the U. S. Geo-logical Survey, however, while still an undergradu-ate, and after field experi- ence in Montana, Wyoming, North Dakota, Colorado and Oklahoma, he went to Mexico as geologist for the Mexican Eagle Oil Co. This was in 1909, and as a result he was unable to complete his work for his degree until 1911. In Mexico, he located the Potrero de Llaño No. 4, one of the world's largest oil wells, and also the dis- covery well in the Naran- jos pool; and the Colorado School of Mines conferred the honorary degree of : Doctor of Science on him in 1925. On his return from Mexico, he engaged in the consulting business, specializing in financial ap- praisement, the Union and Marland companies being among his clients. In 1919, he organized the Amerada Petroleum Co., with the backing of Lord Cowdray. Last year, control of the company was purchased by an American group, headed by Dillon, Read and Co. Mr. DeGolyer is n o w president of the company. He is also vice-president and general manager of the Rycade Corp, the Rycade Oil Corp., and president of the Geophysical Re-search search Corp. The l a t t e r represents the practical appli-cation of his inter-est in the use of the torsion balance in the locating of salt domes, in which he has pioneered, the Nash dome being the first oil field in America actually brought into production by these methods.

Jan 3, 1927

By William P. Blake

In addition to uintaite, the Uintah Mountains contain a deposit, or vein, of the peculiar hydrocarbon mineral, to which I have given the name wurtzilite, * in honor of the chemist, Henry Wurtz, Ph.D., of New York, who, in 1865, described grahamite, and who has added to our knowledge of the composition of the hydrocarbon minerals. Wurtzilite and uintaite are very similar in appearance, but are very different in their physical and chemical properties. Both are black, splendent and shining in fresh fracture; but the wurtzilite has a decided toughness, and a degree of elasticity, especially when warmed, which suggests to some persons a resemblance to caoutchouc. It was at first, at Salt Lake, believed and reported to be a mineral form of India-rubber, and great expectations of its value as a substitute for crude rubber were indulged in. It was, however, found that it would not act like rubber with sulphur; it would not incorporate with it and become "volcanized," and it was very refractory and insoluble in the ordinary solvents of rubber and of uintaite. The elasticity, though unlike the elasticity of rubber, led to the reference of the mineral to the species elaterite, the only name under which an elastic bitumen is described in the mineralogies; and it is so called in the list of the mineral products of Utah, given in the last message of the Governor of the Territory. The name elaterite, as used by Dana, covers at least three differing substances, ranging in specific gravity from 0.905 to 1.223. Two of the varieties are soft and elastic, much like India-rubber, and one is occasionally hard and brittle, imbedded in the softer kinds. All are rare, and comparatively unknown, and not generally represented in mineral collections. One of the varieties referred to here is the subterranean fungus from Derbyshire, described by Lister as early as 1673.

Jan 1, 1890

By F. A. Howard, R. T. Haslam

In a broad sense automotive fuel is simply fuel in general and includes coal, coke, wood, charcoal and gas, in addition to the full range of liquid combustibles. All of these are actually used, or have been used, commercially to some extent as fuel for automotive vehicles. The steam lorry burning coal and coke is a common sight on the roads of England. The fact that these coal-fired steam lorries have a distinct advantage in taxes over the conventional gasoline-driven lorry probably explains the survival of this vehicle. The omnibus, or charabanc, operated by city gas carried in a balloon container on the roof, was also at one time a common sight in England, although not as common as the ubiquitous steam lorry. These gas-operated vehicles have, however, disappeared from the streets in recent years, and probably owed their existence entirely to war conditions. In France one of the largest motor vehicle manufacturers had last year more than 30 trucks equipped with regular gasoline engines in service in the Parisian area operating on producer gas obtained from a small gas producer mounted on the running board of the truck. Both wood and charcoal have been used in these gas producers. The authors were interested enough in this unique commercial development to spend some time examining the apparatus used and inquiring into the success which it had met. The picture is by no means an impossible one purely from the standpoint of practicability, but there is no doubt of the soundness of the conclusion that this is not a development which has any present important significance. Powdered carbonaceous matter, coal, coke or lignite, has been used experimentally in special forms of internal combustion engines, but so far as is known, these have never been applied to automotive practice. Range of Liquid Combustibles In the field of liquid combustibles the full range has been exploited to some extent. Heavy residual fuel oils from petroleum have been

Jan 1, 1928

By L. B. Berger, W. P. Yant

This paper presents evidence of the general occurrence of methane in a large number of the coal fields of the United States and substantiates the apparent unnecessary differences in the ventilation requirements and codes in the various states, as was brought to the attention of the Committee on Mine Ventilation of the American Institute of Mining and Metallurgical Engineers at its Pittsburgh meeting in October, 1925, by J. A. Garcia. The data in his report have been compiled from the files of the Gas Laboratory of the Pittsburgh Experiment Station of the Bureau of Mines and represent samples collected throughout the various states and submitted for analysis by its engineers, also by mine operators and State mining departments, since 1911. Several thousand analyses were available but most of them were rejected because they represented abnormal conditions, undefined place of sampling, special investigations, or duplications in the same mine. Only those samples were included which, without reasonable doubt, were ascertained to fall within three major classes, namely, main return, air splits, and face and rooms of live workings. In the case of air splits, and face and room samples, only the one which contained the highest percentage of methane found in a given mine was taken. OCCURHENCE OF METHANE IN COAL MINES OF THE UNITED STATES Obviously it is not feasible to present the detailed analytical data here and accordingly these data have been compiled into groups in a manner which it was thought would bring out clearly their significance. These are shown in Table 1 which includes the analyses of 310 samples of return air of approximately the same number of coal mines in 19 states. Because of changes in ownership and names the exact number could not be ascertained. The table also includes 337 samples from air splits and 263 from the face and rooms of some of the same mines represented by return air samples and from other mines in these states. A total of more than 400 mines are represented by Table 1.

Jan 1, 1927

By Warren L. Howes

This paper deals primarily with an investigation of ball-mill liners that was conducted by the writer over a period of six years at the Mammoth mill in Arizona. The investigation covered a wide variety of designs of liners in both primary and secondary mills. The comparative results are presented herein as evidence of the extent to which design influenced liner life and mill performance. Flowsheet The feed to the Mammoth mill was a complex, oxidized, gold-silver-lead-molybde-num-vanadium ore with rhyolite, andesite and granite as gangue. Although the ore varied between stopes, the long-term average in character remained substantially the same. Capacity was 560 tons per day.† Fig. I shows an abbreviated flowsheet of the grinding section of the mill. Primary Ball Mill A 3-ft. Symons shorthead crusher in open circuit crushed to 1/4-in. maximum one-way dimension the feed to the 5 by Io-ft. Marcy open-end ball mill. The mill rotated at 80 per cent of critical speed and was charged with 4-in. forged steel balls. Cast balls were used for a few months at a slight reduction in ball cost, but breakage of the large balls reduced the ball size and grinding capacity to a point where the over-all costs suffered out of proportion to the saving in cost of balls. For metallurgical reasons, the finished product of the mill was maintained at minus 8-mesh. This coarse product, plus the very abrasive ore and the absence of fines in the feed, caused abnormally rapid wear of the mill liners. The resultant high operating cost led to the most extensive phase of the investigation. In order to clarify the difference in design of the various types of liners used, Fig. a shows the profiles with the arrangement in which grinding balls of maximum size would lie on the face of the liners. The results with each type of shell liner in the primary mill are shown in Table I. Since most of the testing was done with

Jan 1, 1943

By Warren L. Howes

This paper deals primarily with an investigation of ball-mill liners that was conducted by the writer over a period of six years at the Mammoth mill in Arizona. The investigation covered a wide variety of designs of liners in both primary and secondary mills. The comparative results are presented herein as evidence of the extent to which design influenced liner life and mill performance. Flowsheet The feed to the Mammoth mill was a complex, oxidized, gold-silver-lead-molybde-num-vanadium ore with rhyolite, andesite and granite as gangue. Although the ore varied between stopes, the long-term average in character remained substantially the same. Capacity was 560 tons per day.† Fig. I shows an abbreviated flowsheet of the grinding section of the mill. Primary Ball Mill A 3-ft. Symons shorthead crusher in open circuit crushed to 1/4-in. maximum one-way dimension the feed to the 5 by Io-ft. Marcy open-end ball mill. The mill rotated at 80 per cent of critical speed and was charged with 4-in. forged steel balls. Cast balls were used for a few months at a slight reduction in ball cost, but breakage of the large balls reduced the ball size and grinding capacity to a point where the over-all costs suffered out of proportion to the saving in cost of balls. For metallurgical reasons, the finished product of the mill was maintained at minus 8-mesh. This coarse product, plus the very abrasive ore and the absence of fines in the feed, caused abnormally rapid wear of the mill liners. The resultant high operating cost led to the most extensive phase of the investigation. In order to clarify the difference in design of the various types of liners used, Fig. a shows the profiles with the arrangement in which grinding balls of maximum size would lie on the face of the liners. The results with each type of shell liner in the primary mill are shown in Table I. Since most of the testing was done with

Jan 1, 1943

By J. P. Sheeha, W. F. Craig, M. Baeyertz

The loss in toughness caused by phosphorus within commercial ranges was studied in AISI-SAE 1340 steel and in molybdenum modifications of this grade. The replacement of part of the manganese by molybdenum in amounts which maintain the hardenability of the standard 1340 grade was shown to counteract to a marked degree the detrimental effects of phosphorus. THIS paper deals with the effect of phosphorus on the toughness of 1340 steel and with the effect on toughness of replacing part of the manganese by molybdenum while retaining the same hardenability as that of 1340. In previous work1 a progressive decrease in toughness was observed when the phosphorus content of 5140 was raised from 0.020 to 0.036 pct; that is, from a moderate phosphorus level to one higher but yet within the AISI-SAE specification for this grade. The structural condition of the steel was tempered martensite. Toughness was evaluated by the transition temperature determined by V-notch Charpy tests. Replacement of a part of the chromium in 5140 by molybdenum provided a factor of safety against loss of toughness caused by phosphorus, especially where the steel was cooled slowly after tempering. Scope of the Study: In view of the improved tolerance for phosphorus obtained by replacing a part of the chromium in 5140 with molybdenum, it seemed desirable to investigate the possibility of obtaining similar improvement in 1340 by replacing part of the manganese with molybdenum. Heats were made at different phosphorus levels, in a series that began with 1340 and ended with steels containing 0.32 to 0.35 pct Mo with 0.82 and 0.90 pct Mn. The analyses of the heats are given in table I. In order to facilitate later discussion, the 1340 heats have been placed together in the order of increasing phosphorus content, and the molybdenum modifications have been grouped according to phosphorus

Jan 1, 1951

THROUGHOUT the Colonial era, Philadelphia was easily the leading city of North America, and it still held that position at the end of the period, with a population of about 25,000, though closely pressed by Boston, which had slightly over 20,000, and New York, which had nearly as many. It was the center of a region in which mineral industry was important. Thomas Rutter's bloomery, built in the Schuylkill valley in 1716, was quickly followed by many others, and during the Colonial period at least 20 blast furnaces, 45 forges, and iron- works of other types were built in eastern Pennsylvania, which easily led all the other colonies in iron manufacture. During the Revolutionary period others were erected as far west as Fort Loudon, in the Cumberland c alley.6 After 1800 the rapid development of the anthracite mining industry profoundly affected Philadelphia's development, since transportation of the coal was then necessarily by water,, and the streams of the anthracite regions mostly flowed into either the Schuylkill or the Delaware Rivers. With an abundant near-by supply of coal and iron, with the seat of government, which had been there since 1774, and with a national Bank established there in 1791, one would have seemed safe in prophesying, at the beginning of the nineteenth century, that Philadelphia would permanently remain the leading city of the United States. Education in Philadelphia was at first wholly in the hands of the Quakers, who had established a "Public School" there in 1689, but in November 1739 George Whitefield, who had created a sensation in England by his preaching, though only 24 years old, passed through Philadelphia on his way to Georgia to found an orphan school there. He preached a series of sermons in Christ Church that were so disturbing to the established church that on Nov. 25 the Rev. Richard Peters (who was also Provincial

Jan 1, 1941

By George A. Guess

The increasing demand for greater speed and more accuracy, in making daily assays of ores and products from mills treating material containing but very small quantities of lead and copper, has caused the older analytical methods to be supplanted by new ones devised to meet the needs of modern work. For " control" work in copper-analyses, I had, previous to the present equipment, introduced in my laboratory the ordinary electrolytic method, using hollow cylindrical electrodes; and with these I began a series of experiments in determining the lead-content of daily mill-samples and controls. The results, proving accurate and satisfactory, I then devised, with Mr. H. E. T. Haultain, a cheaper electrode than the ordinary jaCket-electrode, which costs from $15 to $20,—the expense of the older form making the installation of many units very costly. The form of cathode finally adopted as the most satisfactory, shown in Fig. 1, is cut from 0.001-in. platinum foil. It is 12.5 cm. long, and is divided into a blade 4 cm. wide and 6.25 cm. long, and a tongue 0.7 cm. aide and 6.25 long, the immersion area being 50 sq. cm. and weight 1.5 grams. The blade is first sand-blasted and then corrugated lengthwise, in order to impart the necessary rigidity. Strips of platinum foil 0.001 in. thick, 12.5 cm. long and 0.5 cm. aide, having a median corrugation, form the anodes. Three electrodes are used in each cell; one anode in the middle and one cathode on each side of the anode. These electrodes are connected to slotted aluminum terminals, in which they are held by contact pressure. The terminals are 5/16in. rods, projecting 2 in. horizontally in front of the wall of the cabinet; at the back the middle electrode (anode) is connected with one pole of the current, and the two outer ones (cathodes) with the other pole.

Jan 1, 1906

By Warren L. Howes

THIS paper deals primarily with an investigation of ball-mill liners that was conducted by the writer over a period of six years at the Mammoth mill in Arizona. The investigation covered a wide variety of designs of liners in both primary and secondary mills. The comparative results are presented herein as evidence of the extent to which design influenced liner life and mill performance. FLOWSHEET The feed to the Mammoth mill was a complex, oxidized, gold-silver-lead-molybdenum-vanadium ore with rhyolite, andesite and granite as gangue. Although the ore varied between stopes, the long-term average in character remained substantially the same. Capacity was 560 tons per day. [t] Fig. I shows an abbreviated flowsheet of the grinding section of the mill. PRIMARY BALL MILL A 3-ft. Symons shorthead crusher in open circuit crushed to ¼ -in. maximum one-way dimension the feed to the 5 by 10-ft. Marcy open-end ball mill. The mill rotated at 80 per cent of critical speed and was charged with 4-in. forged steel balls. Cast balls were used for a few months at a slight reduction in ball cost, but breakage of the large balls reduced the ball size and grinding capacity to a point where the over-all costs suffered out of proportion to the saving in cost of balls. For metallurgical reasons, the finished product of the mill was maintained at minus 8-mesh. This coarse product, plus the very abrasive ore and the absence of fines in the feed, caused abnormally rapid wear of the mill liners. The resultant high operating cost led to the most extensive phase of the investigation. [ ] In order to clarify the difference in design of the various types of liners used, Fig. 2 shows the profiles with the arrangement in which grinding balls of maximum size would lie on the face of the liners. The results with each type of shell liner in the primary mill are shown in Table I.

Jan 1, 1943

By Charles Macdonald

It may seem to be almost unnecessary to occupy the time of the Institute in further consideration of a question which has been so comprehensively treated in papers already on file in our own Transactions and in those of the American Society of Civil Engineers. Unfortunately, however, the results of these concerted efforts have not been materially to increase our stock of Knowledge in the direction sought for; and as the necessity for this information is becoming.more and more apparent as the demand for structural materials increases, it is believed that by continuing the agitation by means of discussions in this and kindred societies, whose members are vitally interested in obtaining reliable data as to the properties of the materials they are called upon to work with, public opinion may be educated up to the importance of exerting such an influence upon the law-makers of the country as will result in the formation of a competent board, with adequate means at its disposal, to carry out this great work in a manner alike acceptable to the makers and users of the materials in question. It may be proper in the first place to glance briefly at what has been attempted thus hr, then to indicate some of the more important lines of needed investigation, and finally to consider reasons why government aid may with propriety be sought for in carrying on the work. At a convention of the Society of Civil Engineers held at Chicago June 5th, 1872, it was, on motion of General William Sooy Smith, resolved, that, " Whereas, American engineers are now mainly dependent upon formula for the calculation of strength of the different form of iron and steel, not based on experiments upon American materials and manufacture; and " Whereas, There differ greatly in many of their ch~racteristics front thoae of foreign production, both in their nature and forma: therefore,

Jan 1, 1882

By W. C. Lilliendahl, H. W. Highriter

The method developed and used in this laboratory for the production of metallic uranium of such purity that it is ductile and can be cold-worked to fine wire or thin sheet by rolling has already been described1. It consists, briefly, in the electrolysis of potassium uranous fluoride (KUF5) in a molten bath composed of equal parts of sodium and calcium chlorides. The bath is contained in a graphite crucible, electrically heated to about 775° C., the crucible serving as the anode for electrolysis. The uranium deposits in finely divided form mixed with salts upon a molybdenum cathode suspended axially in the crucible. Upon completion of the electrolysis the cathode is removed and cooled, the deposit broken and leached to remove salts. The metal powder is washed with water and dilute acetic acid and dried in vacuo to reduce oxidation. Suitable amounts are then prcssed into pellets and heated in vacuo by high-frequency induction, using a thoria crucible. The uranium melts and flows away from the pellet, leaving a shell, which is largely oxide. In general, this method produced a satisfactory metal, although at times tile uranium was not ductile. The investigations recorded here were made to find the cause of this embrittlement. It was known that the metal generally contained carbon, derived from disintegration of the graphitc crucible in which electrolysis is conducted, in amounts dependent upon the thoroughness of washing the metal powder. Accordingly, analyses of several samples, both ductile and brittle, were made by combustion and absorption of CO² in Ascarite, using air instead of oxygen to reduce the temperaturc and rate of oxidation. Several of these metals were made with special precautions to reduce carbon content. The results show no relationship between ductility and carbon content in the range investigated (Table 1). Microscopic examination of ductile and brittle metals disclosed the presence in the latter of an intergranular constituent, harder than the matrix and less easily oxidizable, which was absent from the ductile material. Rough estimates of the volume of the hard constituent

Jan 1, 1935

By Michael D. Martin

Pima Mining Co., managed and 50% owned by Cyprus Mines Corp., with Union Oil of California and Utah Construction and Mining Co. sharing equally in the remaining 50%, is a medium-sized open pit copper mine situated in the very active Twin Buttes mining district, 22 miles southwest of Tucson, Ariz. In 1965, a three-part paper described Pima's growth from 3,000 tpd (tons per day) in 1957 to 18,000 tpd nine years later. Within months of the completion of the last stage of this sixfold expansion, studies were being wound up on a further major expansion, this time to 30,000 tpd. This expansion is now a reality. Details of the enlargement of the crushing and concentrating plant have already been covered in a recent paper, and the present paper will cover pit engineering studies, equipment selection, and current operating practices. Key factors in top management's decision to go ahead with the latest expansion were: (1) a substantial increase in ore reserves coupled with an appreciable decrease in grade, (2) a generally favorable outlook for copper prices, and (3) better than expected performance by mine and mill equipment purchased for the expansion to 18,000 tpd. For the pit design studies, particular attention was paid to pit stability, a problem area at times in the past, and to the location and grades of the final ramp systems. In drawing up the long-term mining schedule, the attitude of the ore, with the higher grade material lying deeper, was a critical factor and considerable stockpiling of lower-grade material in the early years had to be accepted in order to keep the annual grades close to the average of the orebody. The expansion called for major purchases of mine equipment in order to gear up the mine for delivery of 30,000 tpd to the concentrator. In general, equipment chosen was of types already proven at Pima, al- though there were some exceptions to this practice. One of these excep-

Jan 1, 1969

By E. S. Machlin, A. J. McEvily

HE results of an experimental investigation by McEvily and Machlin have indicated that a strong relationship exists between the processes of cross slip and fatigue. Whenever dislocations can cross onto an intersecting plane and expand thereon, as in AgCl crystals, the usual type of S-N behavior is obtained, but when such a process is difficult, as in NaCl crystals, fatigue does not occur in its usual manner, if at all. MgO, because of its crystal structure (NaCl type) and slip systems ({110}<110>) would not be expected to fail in fatigue. However, Cornet and Gorum2 have found something akin to the usual type of fatigue behavior for MgO crystals. The purpose of this note is to attempt to resolve this apparent discrepancy. In Cornet and Gorum&apos;s work as-cleaved crystals were tested under cyclic axial loading, whereas in McEvily and Machlin&apos;s work chemically-polished crystals were tested in reversed bending. Because of the difference in specimen preparation, the major effort of the present work was directed toward comparing the behavior of as-cleaved as opposed to chemically-polished specimens. The effect of type of loading seemed less important, but a check was made on this also. Eighteen bend tests and one axial load test were made. The specimens were cleaved from Norton magnorite blocks, and measured 1 by 3/16 by 1/8 in. To avoid failures in the grips, the thickness of the bend specimens was reduced from 1/8 in. near the ends to 0.04 in. in the central portion. This reduction was from one side of the crystal only. Twelve specimens were polished in orthophosphoric acid to remove the damage due to cleavage. The other six specimens were not chemically polished so as to maintain the as-cleaved condition of the crystal faces which had not been reduced. The axial-load specimen was reduced from both faces to a thickness of

Jan 1, 1962

By A. S. Nowick, W. A. Goering

INspite of considerable interest in the kinetics of ordering of the alloy Cu3Au there is no direct information available on the activation energy for atom movements in this alloy, such as that obtainable by radioactive tracer-diffusion studies or by internal friction measurements. Accordingly, this alloy was examined to find out whether it displays an internal friction peak resulting from stress-induced ordering, similar to that studied extensively in other alloy systems.1-3 Measurements of the internal friction as a function of temperature were made in a torsion pendulum similar to that described by Ké.8 Wire specimens 0.032 in. diam and 11 in. long were used. The wire, obtained in the cold-drawn condition,* was annealed at 900C in a quartz tube to obtain a large grained sample, and then mounted in the torsion pendulum furnace. Internal friction is reported here as the lag angle, 4, which is equal to the logarithmic decrement divided by .ir. Fig. 1 shows the internal friction at three frequencies (the frequency given for each curve is the value measured at the peak). The data for these curves were obtained on cooling one specimen from 460C to just above the critical temperature for long-range ordering, which is about 390C for this alloy. In this way, the internal friction is measured under conditions where the alloy is in the disordered condition throughout the run. The curves obtained at frequencies of 2.15 and 1.29 cps show peaks in the range of measurement. The corresponding peak for the 0.78-cps curve is estimated, from the shift of this curve relative to the others, to be located slightly below the critical temperature (at 385C). The fact that the peak can be observed above the critical temperature is good evidence for the belief that it is a stress-induced ordering phenomenon similar to that which is observed in other disordered alloys. The fact that the peaks in Fig. 1 are not the same

Jan 1, 1959

By P. de Vitry, Oliver Bowles

THE conventional wire saw, introduced in the slate district of Pennsylvania by the Bureau of Mines in 1927, and used thereafter with remarkable success, consists of a three-strand steel cable having a diameter of 3/16 or 1/4 in. The equipment, methods used, and accomplishments have been described in previous reports.1-7 Similar wire saws have been used extensively in Europe, in quarries and in shaping blocks and slabs. During the period 1932-1937, competition in European marble quarries was keen, prices were declining, and orders were not abundant. When orders were received, there was generally an urgent call for speedy delivery. Because of the diversification of demands, it was impossible to maintain in stock marbles of the color, size, and thickness called for, therefore the material generally had to be fabricated after the order was received. The wire saw enabled stone mills to fill such orders promptly. With skillful handling, 7/8-in. slabs could be cut accurately and rapidly with this equipment. It was found, however, that, as the three-strand wire became worn, the cutting speed dropped rapidly and the cut became less accurate. To overcome these difficulties the junior author of this paper, after much experimentation, developed a new type of wire consisting of a single ribbon-shaped strand, twisted as shown in Fig. 1. To ensure straight sawing, the twist of the ribbon is reversed from right to left and vice versa every 25 ft. The reversal of the [ ] twist is shown in Fig. 2. This is not a new feature; it has been used to advantage with the three-strand wire both in Europe and America for several years. However, some difficulties arise in splicing the three-strand reverse-twist wire, and the claim is made that cutting is less accurate as the wire becomes worn. To make an endless belt, the ends of the single-strand wire are brazed together with

Jan 1, 1941

By W. C. Lilliendahl, H. W. Highriter

The method developed and used in this laboratory for the production of metallic uranium of such purity that it is ductile and can be cold-worked to fine wire or thin sheet by rolling has already been described1. It consists, briefly, in the electrolysis of potassium uranous fluoride (KUF5) in a molten bath composed of equal parts of sodium and calcium chlorides. The bath is contained in a graphite crucible, electrically heated to about 775° C., the crucible serving as the anode for electrolysis. The uranium deposits in finely divided form mixed with salts upon a molybdenum cathode suspended axially in the crucible. Upon completion of the electrolysis the cathode is removed and cooled, the deposit broken and leached to remove salts. The metal powder is washed with water and dilute acetic acid and dried in vacuo to reduce oxidation. Suitable amounts are then prcssed into pellets and heated in vacuo by high-frequency induction, using a thoria crucible. The uranium melts and flows away from the pellet, leaving a shell, which is largely oxide. In general, this method produced a satisfactory metal, although at times tile uranium was not ductile. The investigations recorded here were made to find the cause of this embrittlement. It was known that the metal generally contained carbon, derived from disintegration of the graphitc crucible in which electrolysis is conducted, in amounts dependent upon the thoroughness of washing the metal powder. Accordingly, analyses of several samples, both ductile and brittle, were made by combustion and absorption of CO² in Ascarite, using air instead of oxygen to reduce the temperaturc and rate of oxidation. Several of these metals were made with special precautions to reduce carbon content. The results show no relationship between ductility and carbon content in the range investigated (Table 1). Microscopic examination of ductile and brittle metals disclosed the presence in the latter of an intergranular constituent, harder than the matrix and less easily oxidizable, which was absent from the ductile material. Rough estimates of the volume of the hard constituent

Jan 1, 1935

By W. T. Thom

RegaRding the elements necessarily involved .in working out a scientific scheme of classification, Stansfield and Sutherland, (94)† quoting Grout, (34) make the following statement: All bases (for a scientific classification) should be capable of quantitative determination, or be exactly related to some property capable of such a test, so that, if no natural groups are found, arbitrary lines may be drawn to limit the classes. The best basis for classification should involve inherent and fundamental qualities of the materials considered. Allied to this is the requirement that advantage should be taken of any natural grouping. As a further help in selection, the bases or tests should be easily applied, widely known, and have a wide range of values in the material classified. In order that we may apply the philosophy thus expressed, it is necessary for us to have clearly in mind both the reasons why coals differ and the specific purposes to be served by the classification to be devised. Coals differ because, as modern science has shown, coal beds are actually neither more nor less than buried and altered peat deposits, formed in remote geologic time. And as is generally known, such peat beds consisted of masses of partly macerated and decayed trees, shrubs, plants, mosses and/or algae, deposited under swamp or semiswamp conditions. It is therefore to be expected that coals will vary: 1. Because of differences in the parent vegetation, due either to evolutionary plant changes, as from the fernlike types of the Paleozoic to the coniferous and hardwood types of the late Mesozoic and Tertiary; or due to the differences in floral assemblages (growing at the same time) induced by differences in local environmental conditions. For example, moss, sedge, woody and other peats are today accumulating simultaneously in different bogs in North America. 2. Because of differences in the stage to which bacterial decay proceeded in the peat bed. Peats laid down in stagnant waters suffer

Jan 1, 1932