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By R. G. Weavind, R. S. Young, I. Wolf

ONE of the most important fields of investigation at the Diamond Research Laboratory in Johannesburg is concerned with improvements in metallurgical practices for the diamond mining companies, with particular reference to increased recoveries of the smaller industrial stones. Considerable work has been done on the possible application of flotation processes to the diamond industry. From the viewpoint of recovery processes, diamonds in their natural state may be grouped into two classes, the water-repellent diamonds, which adhere to a grease surface, and the water-avid diamonds, which, because of their wettability, will not adhere to a grease surface and must be recovered by means other than the grease tables used for water-repellent diamonds. Experiments in the flotation of small diamonds from both kimberlite and alluvial deposits indicate the following conclusions: Water-repellent diamonds: Satisfactory flotation of —16 mesh diamonds, which are naturally water-repellent, may be accomplished using either Aero-float 25 together with cresylic acid, or Du Pont B23 as frother together with kerosine as auxiliary oily conditioner or froth stiffener. The quantities of reagents required are of the order of 0.15 lb per ton Aerofloat and 0.18 lb per ton cresylic acid. The use of acid circuits is detrimental, and for best results a pH between 7 and 9 should be maintained. R. G. WEAVIND and I. WOLF are with the Diamond Research Laboratory, Johannesburg, South Africa, and R. S. YOUNG, Member AIME, is Director of Research, Diamond Research Laboratory. TN 76B. Manuscript, March 23, 1951. A flotation period of 5 to 10 min is necessary to insure that all floatable diamonds are removed. Diamonds larger than 16 mesh cannot be recovered satisfactorily by flotation. Xanthates do not act as collectors for diamonds, and this is probably associated with their inability to impart a water-repellent surface to this mineral. Water-repellent diamonds smaller than 28 mesh can be floated quite well by the addition of a frother alone, such as pine oil or Du Pont B23. Water-avid diamonds: Partial flotation of the smaller sizes of wettable diamonds can be achieved by preconditioning with fatty acid soaps, cationic amines, and similar reagents, which will impart a water-repellent film to diamonds. Washing to remove excess reagent, followed by flotation, will result in a fair recovery, but the latter is much lower than for water-repellent diamonds. Crushed boart: Recovery of crushed boart from the waste products of industrial uses is best accomplished by first conditioning the diamonds present in the mixture with fatty acids, cationic amines, etc., removing the conditioning agent by washing, and floating in a cell of the pneumatic type. Flotation reagents found to be most suitable are Du Pont B23, and Aerofloat 25 together with cresylic acid. The optimum quantities are 1.2 g Du Pont B23, and 0.55 g Aerofloat plus 1.4 g cresylic acid, per liter of pulp in the cell. A solids-to-water ratio of 1 to 4 is found to be the most suitable, and alkaline circuits are necessary for best results. Diamonds larger than 28 mesh are not recovered satisfactorily by this procedure, but for finer sizes flotation offers an excellent procedure for the reclamation of this strategic industrial material.

Jan 1, 1952

By C. M. Nickerson

IT is apparent that repressuring of the oil measures is becoming increasingly important to the oil industry, and is a matter that warrants the best efforts of the petroleum engineer charged with applying this method of operation to a producing property. Considerable attention has. been directed to repressuring in various California oil fields, such as Dominguez and Seal Beach, which have served to sell the more progressive operator on this idea and also to keep him sold. The projects that have received most attention are in comparatively young fields where the fluid levels are high, the wells, perhaps, still flowing, where the wet gas production is of considerable volume, and where there is vital need of immediate conservation of gas, which otherwise would be blown to the air. The new State of California Gas Law, which prohibits the waste of gas, has served to interest the oil industry in -means of conserving the gas that is now being blown to the air because of lack of markets. This vitally affects the operator in the older, well-depleted oil fields of the state, because in many cases he has a limited market for gas, on account of the flush production from the more active oil fields. While the waste of gas is relatively small in these older fields, such as the Midway-Sunset area, it now attains considerable importance, since under the new State Gas Law it must be put to some beneficial use. Repressuring in the older fields of California has not received the attention of the petroleum engineers that is warranted by the present situation. This paper was prepared with the view of presenting the salient features connected with repressuring in the well-depleted oil measures of the older fields, and to show what results have already been obtained in these fields by injecting the unmarketable. gas into the sands, particularly in the Midway-Sunset field in the San Joaquin Valley of California. Other projects in the older fields of the state offer some supporting data in this connection, such as the Shields Canyon and the Brea Canyon fields.

Jan 1, 1929

By Edward Steidle

Those who have followed the rapid progress in rock-dusting bituminous-coal mines must admit that opinion crystallized during the year just closed in support of this preventive of coal-dust explosions. Up to 1924 only one mining company in America practiced rock-dusting on a large scale, but during 1924 forty-two companies had adopted this safety measure, and the "boom" is expected to extend over the next two or three years. Alabama is represented by 1 company, Colorado by 3, Illinois by 4, Kentucky by 1, New Mexico by 4, Pennsylvania by 20, Utah by 8, and Wyoming by 1. A total of about 500 miles of entry has been dusted. Illinois leads with 275 miles of dusted entries and Pennsylvania holds second place with about 175 miles. In each case there is a sense of great security, not only on the part of the operator but by the miner as well. It is also interesting to note that during 1924 the compensation rating or inspection bureaus in twelve of our coal-producing states revised their rating schedules so that a credit would be given for rock-dusting. This credit ranges from 10 to 20 cents per $100 payroll. Recent drastic federal and state regulations approved by mine operators made rock-dusting compulsory in bituminous coal mines in Utah, beginning July 1, 1924. Legislative action favorable to rock-dusting may be expected in other states. Colorado has already proposed a change in its laws, and Pennsylvania, Maryland, Washington, and West Virginia are giving the matter consideration. If the rock-dusting problem is handled properly and proves to be entirely successful, no mining man of any standing will delay applying it in his mine. State legislation regarding this matter may or may not solve the problem. At present, the mining companies that are rock-dusting of their own choice are doing it carefully and thoroughly. In Utah, some are doing it conscientiously, trying to get what benefits can be obtained while others are reported to be doing it only to keep within state regulations. In any event, if we are to have new legislation, it is essential that the various states know what they are about and then, if possible, work for uniform regulations.

Jan 1, 1925

AALL,Christian H.,(M '49), Asat.Research Dir , Phosphate Div Monsanto Chem.Co.,Monaanto, Tenn. AAMOT,Olav Crone, (M '29), Dir of Tech., Chromium Min. & Smelt. Co Ltd Box 6215, Hillyard, Spokane, Wash. AARING, Floyd Daniel, (J '48), Prod. Engr., Canadian Gulf Oil Co., 8035 - 102nd St., Edmonton, Alta., Canada AASE, Glenn D., (J '40), Met Engr Western Research Div. ,Amer. Smelt. & Refin. Co., Selby, Calif ABADIE, Henry G (M '43), Senior Prod Engr., Long Beach Oil Dev Co., 255 S Santa Clara Ave Long Beach 2, Calif. ABBOTT,Clarence E (M '04), Civil Engr., 901 Insurance Bldg., Raleigh, N.C. ABBOTT, John, H., (M '46), Resident Mgr., Hickman, Williams & Co., Rm 2205,230 N Michigan Ave., Chicago 1. I11.

Jan 1, 1952

By William L. Russell

A new instrument for measuring bulk and grain vol-urnes is described, and compared in accuracy with two modifications of Nutting's method, All three methods are reasonably fast, and in all three the probable error in the determinations of bulk volume can be kept down to about 0.1 to 0.2 per cent. INTRODUCTION The new pycnometer described in this paper is designed to give speed without sacrificing accuracy. Some time ago Russell1 described a somewhat similar appa-ratus; however, the instrument described in the present paper is more accurate. Nutting' designed the pycnom-eter shown in Fig. 1 (A and B), and Pirson3 has shown points like those of Fig. 1-D. The procedure described in this paper for using Nutting's pycnometer has been modified from that used by Nutting. CHOICE OF LIQUIDS The best liquids for measuring grain volumes are hydrocarbons or chlorinated hydrocarbons which evaporate slowly. Trimethylbenzene or mesitylene, triethylben-zene, carbon tetrachloride, and tertalin have been used for this purpose. Any of these liquids or mercury may be used for measuring bulk volume. PREVENTING ERRORS DUE TO INVASION OF LIQUID Errors due to the invasion of the porous, permeable bulk samples by the liquid of measurement may be prevented or greatly reduced by using mercury, by applying an impervious coating, or by soaking the bulk samples in the liquid of measurement until bubbles cease issuing from them. Errors are produced only by the invasion of the samples which occurs between movement when the samples are weighed in air and the moment the weight of liquid displaced by the sample in the pycnometer is determined. No error is produced by varying degrees of filling of the pore space of the samples by the liquid of measurement. The excess liquid should be wiped from the samples immediately before the weight in air W1, is determined, and they should be placed in the pycnometers immediately. OPERATION OF NEW INSTRUMENT The new pycnometer is shown in Fig. 2. It consists of two glass parts which fit together at a ground glass joint. The spaces J and D are connected by fine glass tubes E, and the space J must be larger than the space D by at least the volume of the largest sample to be tested. The projections H afford a grip for twisting when the two parts tend to stick together. The position of the sample in mercury is shown by I, and in other liquids by M. F is a permanent mark on the glass, and G is a tem-Some marker. In order to determine the position at which G should be placed, invert the instrument so that A is at the bottom, and fill space D. Place the cub K

Jan 1, 1958

By M. R. Geer, H. F. Yancey, P. S. Jacobsen

Two growing problems confront the preparation engineer—still further restrictions on stream pollution and a greater proportion of fine coal as more and more continuous miners come into use. The de-watering screens, centrifuges, and settling ponds that sufficed a few years ago must often be supplemented by more effective equipment, and in some instances the finest solids are now being recovered by vacuum filtration, once considered too costly in many coal washeries. Unfortunately not all slurries can be readily filtered. Some are virtually unfilter-able, and others do not permit the high cake rates needed to hold costs within reason. Often, however, these difficult slurries can be rendered filterable by flocculation. Starch and lime have long increased settling rate in thickeners and can also aid filtration. More recently there have been other flocculants, primarily synthetic polymers or gums. Reports of their great effectiveness prompted the U. S. Bureau of Mines to test their use in filtration as part of its program on recovering and cleaning fine coal. The object of the present work was to compare some of the newer flocculants with starch and lime and to test the reaction of different types of slurries to flocculation. Three natural slurries, three synthetic coal-clay mixtures, and five flocculants were tested, all with a laboratory filter leaf. Slurries and Flocculants Tested: First of the slurries was the thickener feed from the washed coal section of the Michel colliery of Crow's Nest Pass Co. Ltd., Michel, B.C. As shown by the screen and ash analyses in Table I, practically all this slurry was finer than 28 mesh, and about half the solids were finer than 200. Substantially all material coarser than 200 mesh was clean coal, but the ash content of 20.7 pct in the finest size indicates a moderate amount of impurity. This coal is medium-volatile bituminous in rank. Slurry was also obtained from the Black Diamond washery of Palmer Coking Coal Co., King County, Wash. This underflow of a 1/2-mm vibrating slurry screen is a waste product discharged to a settling pond. As shown by the data in Table I it contained about 20 pct material finer than 200 mesh, which analyzed 77.5 pct ash, indicating a high proportion of clay. The coarser sizes were also high in ash content because of the presence of bone and shale. Black Diamond coal is on the dividing line between bituminous and subbituminous rank. The third slurry, from the washery of Roslyn-Cascade Coal Co. in Kittitas County, Wash., was the underflow of a battery of 8-in. cyclones that is wasted with the coarser refuse from the plant. In both size and ash content this slurry was similar to the Black Diamond, but since it was a cyclone-underflow product, the fraction finer than 200 mesh undoubtedly contained a much smaller proportion of finely divided clay than was present in the Black Diamond slurry. The Roslyn-Cascade coal is high-volatile A bituminous in rank. Initially the slurry samples were stored in the laboratory at a concentration of 40 pct solids. A progressive change in filtration and flocculation characteristics during storage was noted, however, presumably because of progressive disintegration of the clay. After careful testing demonstrated that the slurry solids could be dried and then repulped without changing the original filtration characteristics, this procedure was adopted. The flocculants used were Separan 2610, Kylo 27, Jaguar MD-A, Idaho potato starch, and lime. The lime was used as a slurry, the Separan 2610 as a 0.10 pct aqueous solution, and the other flocculants as 0.50 pct aqueous solutions. The starch was causti-cized with sodium hydroxide before use. As some of the flocculants are reported to deteriorate on storage, new batches of flocculants were prepared every two days. Test Procedure: Fig. 1 diagrams the filter leaf apparatus employed. This consists of a test leaf having an effective area of 0.10 sq ft., a 60°, 8 1/2-in. diam cone to hold the slurry sample, a variable-speed electric stirrer, vacuum gage, bleed line for controlling vacuum, filtrate flask, moisture trap, and vacuum pump. Two filter cloths were selected—Saran SA 603, a monofilament, coarse-weave cloth, and polyethylene PO-801 HF, a monofilament, fine-weave cloth. The Saran was selected to provide maximum cake rate without regard to clarity of filtrate and the polyethylene to provide the best quality of filtrate without regard to cake rate. The test charge for the filtering vessel consisted of 800 g of solids (previously soaked for 24 hr) and

Jan 1, 1960

By F. W. Glaser, Benjamin Post

A LTHOUGH most transition metals form a wide variety of boride compounds, the existence of only one zirconium boride, ZrB2, had been established prior to this investigation.' The crystal structure and some properties of a hitherto unreported zirconium boride, ZrB12, are described in this paper. Only one other dodecaboride of a transition metal, UB12, has been reported up to the present.' Chemical analysis of the new compound showed 44 pct Zr and 56 pct B, compared with 41 pct Zr and 59 pct B computed for ZrB12. The difference is within the range of error of the analytical method employed. ZrB12 shows marked metallic properties. It is obtained as a fine black powder. Measurements of electrical resistivity were made at —79°C, + 22°C and +64°C. At 22°C the electrical resistivity is approximately 60 microhm-cm. Over this range the temperature coefficient of resistivity is +0.00162. The thermal conductivity at room temperature is 0.122 watts per cm per "C. The product of the electrical resistivity and thermal conductivity is therefore 8.05, which is not far from the normal Wiedemann-Franz ratio (approximately 7.5 at room temperature). These measurements were made on hot pressed samples which were not always high density specimens. The hardness of ZrB12 on the Rockwell A scale varies between 92 and 92.5. Crystal Structure Determination Single crystals of ZrB12 of a size suitable for X-ray diffraction analysis could not be obtained and powder samples had to be used. Filtered Cu radiation was used throughout. Powder diagrams were indexed on the basis of a face-centered cubic unit cell. After correction for film shrinkage, a Bradley and Jay extrapolation³ to ? = 90" indicated that a, = 7.408 ±0.002A. The volume of the unit cell is 406.5A.V he assumption that there are four "molecules" of ZrB12 per unit cell leads to an X-ray density of 3.63 g per cc. The measured density is 3.7 g per cc (as measured by the immersion method). Relative intensities of reflections were determined by integrating the intensities of diffraction peaks using the count register of a North American Philips wide range spectrometer. Intensities measured in this way showed good agreement with photographic intensities estimated visually using multiple film techniques. The usual Lorentz, polarization, and multiplicity corrections were applied to the observed intensity measurements. There are striking similarities between ZrB12, and UB12. The unit cell of the latter is also face-centered cubic and contains four molecules. a, = 7.473, compared with 7.408 for ZrB12. The radius ratio rB/rU is 0.57; rB/rZr is 0.54. In both ZrB12, and UB12 the four metal atoms in each unit cell are in special positions; only the boron positions need be determined. The latter may be inferred from the extent to which diffraction of X-rays by the 48 boron atoms reinforces or weakens the diffraction by the metal atoms. This effect is relatively much greater in the case of the zirconium compound. In their determination of the crystal structure of UB12, Berthaut and Blum' assumed holohedral symmetry (space group Oh5 , Fm3m) and reported that the U atoms are in positions 4(a): 000; 01/2 1/2; ½ 0 ½ ; ½ ½; the boron atoms were reported to be in positions 48(i) with x = 1/6: ½xx; ½xx; x½x; x½x; xx½; xx½; ½xx; ½xx; x½x; x½x; xx½; xx½

Jan 1, 1953

By Douglas J. Harvey

The surface tension of lead-tellurium alloys (in the range 0 to 6.70 at. pct Te) ad lead-arsenic alloys (in the range 0 to 10.53 at. pct As) has been examined by the maximum bubble pressure method. The surface tension of high purity lead can be expressed over a range of temperatures (M.P. to 750°C) by the relationship = 512 — 0.133t. Arsenic and lellurium were both found to be surface active in lead. The surface excess concentration at 700°C was .found to be constant at 0.74 x 10-10 moles per sq cm for tellurium. The surface excess of arsenic at 700°C varied between 0.26 x 10-10 moles per sq cm at 0.16 at. pct to 1.5 x 10-10 moles per sq cm at 8.3 at. pet. The surface tension of lead has been investigated sporadically over the last 90 years. The first recorded study was made by Quincke1 who used a rather crude application of the drop-weight method. Hogness2 obtained the first reliable value for the surface tension of lead by measuring the pressure necessary to force the liquid metal from the end of a small capillary of known radius. Hogness gives the empirical formula: ?(surface tension)= 444 - 0.077 (l-327) which describes the relationship between surface tension and temperature ("C); This work was followed by that of Bircumshaw3 who applied the two-capillar maximum bubble pressure method of Sugden.4 The values published by Bircumshaw are in good agreement with those found by Hogness. Matuyama5 examined the surface tension of lead by the drop weight method. However, the values found are somewhat higher than those previously reported. More recent investigations by Greenaway6 and by Melford and oar' have resulted in data which are not in close agreement, but which are well within the expected range at most temperature levels. The study of the surface tension of lead alloys began with Drath and sauerwald8 who examined the lead-bismuth system. They found that the surface tension values of the alloys in this system deviated only slightly from the ideal mixture rule. Matuyarna5 examined the lead-antimony system. Bircumshaw the lead-tin, and the lead-indium system was studied by Hoar and Me1ford.10 The results of these investi- gations are summarized in Fig. 1. It may be seen that the data vary only slightly from the ideal mixture rule. As none of the metals studied and reported in the literature has a very interesting effect on the surface tension of lead,*the next logical step might be to examine the effect of metals of low solubility or nonmetals having some liquid solubility. Baes, and Kellogg11 have pointed out that the elements most likely to be surface active in liquid metals are ones of limited solubility in the liquid state and possessing weak intermolecular bonding forces in the solid state. Therefore, Group V, VI and VII nonmetals are most likely to be surface active. It was decided to examine the effect of a borderline metal, arsenic, and a nonmetal tellurium. Arsenic forms a eutectic with lead having a melting point of 290°C and a composition of 6.9 at. pct As.13 Pure arsenic sublimes when heated above 610°C. Even though alloying with lead lowers the vapor pressure, fumes containing arsenic are evolved at a very noticeable rate when lead-arsenic alloys are heated above 650°C. Tellurium raises the liquidus temperature of lead sharply to 904°C,14 the melting point of PbTe (lead-telluride). The solid solubility of tellurium in lead was determined by Greenwood and worner15 to be 0.0007 at. pct at room temperature. EXPERIMENTAL METHOD Surface Tension Measurement—The two capillary maximum bubble pressure method for measuring surface tension developed by Sugden,4 and used later

Jan 1, 1962

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872-1874 A L HOLLEY1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 - 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882 ROBERY W HUNT 1883 JAMES C, BAYLES 1884-1885 ROBERT H RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B POTTER 1888 RICHARD PEARCE 1889 ADAM S HEWITT 1890

Jan 1, 1923

By Y. C. Liu, H. Margolin

Investigation of martensite habit plane in water-quenched Ti-Mn alloys was carried out in the range of manganese contents between 4.35 and 5.25 pct. On the basis of 22 measurements, the poles were observed to fall into two groups, indicating the existence of two habit planes. The Miller indices of the poles close to these two groups were found to be <334>ß and <344>ß. TITANIUM has an allotropic transformation at 882.1° ± 0.5C1 by which the high temperature ß (body-centered cubic) phase changes to a (hexagonal close-packed) phase. It is well known, as in the case of low carbon steel, that the unalloyed high temperature ß phase cannot be retained no matter how rapid the cooling rate. However, the addition of alloying elements usually lowers the transformation temperature continuously and stabilizes the ß phase to a temperature much lower than the allotropic transformation temperature in pure titanium. A typical example of this behavior is found with manganese-alloying of titanium. Fig. 1 shows the titanium-rich Ti-Mn equilibrium diagram as established by Battelle Memorial Institute.&apos; The addition of manganese lowers the ß transus line and the eutectoid reaction takes place at 550°C, the eutectoid composition being 20 wt pct Mn. However, upon quenching to room temperature from the ß field, the ß phase can be completely retained with much less manganese, see Fig. 2. If the composition is less than that required to stabilize the ß phase completely, a plate-like structure, similar to that of martensite in other alloy systems, appears as shown in Fig. 3. Much lower alloying content merely intensifies the amounts of these transformed structures, as shown in Fig. 4. This paper presents the results of an investigation of the habit plane of these martensitic structures in Ti-Mn alloys. Experimental Procedure Investigation of the pole of a given platelet was made using the two-surface method of analysis." In order that a given martensite trace on two surfaces be readily recognized both at low and high magnifications, it is desirable that only a small amount of martensite be present. From a review of the data obtained at Battelle Memorial Institute4 on quench hardening in Ti-Mn alloys and the results of Duwez" on transformation in Ti-MO alloys, it was decided that the most appropriate Ti-Mn composition for this study would be about 6 pct Mn. A group of alloys containing from 3 to 10 pct Mn was made to bracket this composition. The choice of the 6 pct alloy was apparently proper, since it was later learned that approximately 5.5 to 6 pct Mn is required to stabilize the ß phase on water quenching.

Jan 1, 1954

David THOMAS 1871 R. W. RAYMOND 1872-1874 A. L. HOLLEY 1875 ABRAM S. HEWITT 1876 T. STERRY HURT 1877 ECKLEY B. COKE 1878-1879 WILLIAM P.SHINN 1880 WILLIAM METCALF 1881 RICHARD P. ROTHWELL 1882 ROBERT W. HUNT 1883 JAMES C. BAYLES 1884-1885 ROBERT H. RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B. POTTER 1888 RICHARD PEARCE 1889 ABRAM S. HEWITT 1890 JOHN BIRKINBINE 1891-1892

Jan 1, 1929

By James E. York

AT a meeting of the American Society for Testing Materials at Atlantic City, June, 1908, Dr.. C. B. Dudley, in his presidential address,&apos; showed the vital necessity of not only making a steel rail as good as in the past, but of making it considerably better in order to meet the present and prospective require¬ments of railroads. Doctor Dudley requested the co-operation of all who from personal experience could give information that would result in bringing about the production of a steel rail that could be relied upon to meet the present requirements. I have had considerable experience in the practical manufacture of steel of almost every grade, during the past 40 years, and I shall suggest changes that will bring about the results desired. Doctor Dudley has had a long experience as chemical and metallurgical expert for the Pennsylvania railroad, but he frankly admits that up to the present time both he and other metallurgical experts lack the practical knowledge of steel-making that is necessary to state correctly the reasons for the unreliability of the steel rails now produced. The necessity is self-evident for more positive practical knowledge on the part of these experts of what is possible and what is impossible regarding the practical manufacturing of steel rails from the ingot to the, finished product. Chemical knowledge in steel-making is far in advance of what it was years ago, and might be said to cover every requirement (in that department) for producing reliable steel. The study of the metallography of steel has been of great value, also the physical testing of steel, but this knowledge will only de-

May 1, 1909

By Samuel S. Wyer

THE following description of methods for conducting gas-producer tests is probably the first attempt to give the subject an analytical, thorough and comprehensive treatment. In some cases where tests have been made, the methods have been so unsystematic and ambiguous that it has been impossible to secure comparable results. To eliminate this difficulty, the following provisional code of gas-producer tests-which has some resemblance to the code of boiler-trials of the American Society of Mechanical Engineers-has been developed. The primary object in testing a gas-producer is to determine whether the producer is working satisfactorily or, what is the same. thing, to see if the efficiency is as high as it should be with the type of producer in question, and also to find out if the composition of the resulting gas is adapted to the work it has to do. In order that the test shall be of any value, it must be thorough and comprehensive, and must be conducted with skill and care. When so conducted, the test will reveal the economy of the producer; and, by making suitable changes, the efficiency will often be increased very much. As a result of the tests made by Jenkins, 1 the efficiency was raised from 56.2 to 71.2 per cent. This shows the large saving that may frequently be made in the fuel-consumption by studying the results of a careful test.. The log of the test, given in Fig. 1, shows that, just as soon as the temperature became regular, the percentage of CO, decreased and that of CO increased.

Mar 1, 1905

By E. G. Schempp, W. A. Morgan

The influence of modifications in the molybdenum, vanadium and, to a limited degree, carbon and boron content to a basic composition of 5 pct Cr, 0.75 pct Mo, 1 pct V hot-work tool steel composition, was studied in respect to hardenability, grpain- coarsening temperature, and tempering charactevistics. Tensile, impact, and fatigue pvoperties were studied for the most promising compositions. An alloy with a typical composition of 0.43 pct C, 4.97 pct CI-, 0.33 pct Si, 2.25 pct Mo, and 1.00 pct V uas found to offer the most favorable combination of properties in respect to high-strength applicntions when tempered at 1100°F. MANY 5 pct Cr high-strength steels are at present being manufactured in North America which fit well into the classification of the AISI-SAE system. Much interest has been shown in these materials as ultra-high-strength steels for use at elevated temperatures. The limiting temperature of use lies at the point where the steels begin to soften rapidly. Although a great deal of information has been made available in the past two years on the properties of selected alloys in this series, little information exists on the effect of systematically varying the ccntent of one or more elements in the 5 pct Cr-base alloy. This paper presents the results of an investigation of the effect of variations of the carbon, molybdenum, vanadium, and, to a limited extent, the silicon, manganese, boron, and niobium content of a 5 pct Cr steel to the AISI H-13 base analysis. EXPERIMENTAL PROCEDURE All experimental heats were melted in a 50-lb. induction furnace. The melting stock consisted of

Jan 1, 1962

By ED. E. Furman, R. H. Atkinson

HITHERTO the practical creep testing of precious metals has received little or no attention. The only previous creep tests of precious metals have been made with wires under conditions such as to yield much more rapid rates of creep than in engineering tests.&apos;, &apos; Up to the present time the value of creep bars of adequate size, in the absence of real need for engineering data, has deterred investigators. However, the increasing use of platinum at high temperatures has demonstrated the need for reliable creep data for the guidance of engineers, especially those engaged in designing certain specialized chemical plant equipment. In order to supply this need, creep tests were conducted at 1382°F (750°C) on 0.290 in. diam specimens of platinum, 90 pct Pt, 10 pct Rh and palladium. The platinum was high purity, nominally 99.95 pct Pt. The 90 pct Pt, 10 pct Rh was of the same high quality as is used for making gauzes for the catalytic oxidation of ammonia. The palladium was also of high purity; two batches of palladium bars were tested, one deoxidized with calcium boride and the other with aluminum. Spectrographic examination of the palladium confirmed its good quality; the only significant impurities apart from the residual deoxidizers were traces of silicon and lead. Procedure The creep bars, which were furnished by Baker and Co. to our specification, were 6 ¾ in. in overall length with a 4½ in. (4 in. gage length) reduced section 0.290 in. in diam and had the ends threaded (?-NC16). It may be of interest that the bars were valued at up to $600 each. The specimens were supplied in a 50 pct cold-worked condition to facilitate attachment of the creep extensometer, which was of the push rod type. Because of the softness of the platinum and palladium, the extensometer rings were secured to the test section by means of circular knife edges instead of the usual pointed set screws. The extensometer rods extended through the bottom of the furnace and readings were taken with a 0.0001 in. "Last Word" dial gage fastened to the rods for the duration of the test. The bars were directly loaded by hanging weights from the lower specimen grip. All tests were conducted at 1382°F ± 2°F, and an effort was made to maintain the temperature gradient over the test section within 2°F. The ends of the furnace tube were packed with asbestos wool, which allowed a very slow circulation of air through the tube. Annealing was accomplished in the creep furnace before the load was applied. The platinum and palladium specimens were annealed at the test tem- perature for about 17 and 24 hr respectively; in the case of the rhodioplatinum it was found expedient to anneal for 1 hr at 1922°F (1050°C). Pilot samples cut from the same stock as the bars were used to check annealing procedures. Pertinent measurements of grain size and hardness were recorded. Results and Discussion The creep data obtained are given in Table I and the creep curves are plotted in Figs. 1, 2, and 3. Two platinum specimens, tested under a stress of 250 psi, had almost identical creep rates at 2000 hr, namely 0.000008 and 0.000009 pct per hr. A third platinum specimen, stressed at 400 psi, had a creep rate at 2000 hr of 0.000026 pct per hr; the reason for a rather sharp decrease in creep rate during the period from 1200 to 1600 hr is unknown. As it was thought that 90 pct Pt, 10 pct Rh would have a lower creep rate than platinum, the first sample was tested at 400 psi; however, the creep rate was approximately 50 pct greater. Microex-amination revealed that differences in grain size might be responsible for the unexpected result, as annealing at 1382°F developed an average grain diameter of 0.0021 in. in the rhodioplatinum specimen compared with 0.004 in. in the platinum bar. Annealing the alloy for 1 hr at 1922°F (1050°C) increased the average grain diameter to 0.0032 in. and materially improved the creep resistance, making it much better than platinum. A second specimen annealed at 1922°F (1050°C) and tested under a stress of 550 psi had a creep rate of 0.000022 pct per hr at 2000 hr, which was still substantially lower than that shown by the specimen annealed at 1382°F (750°C) and stressed at only 400 psi. In contrast to the creep behavior of the platinum and rhodioplatinum specimens, the palladium bars, whether deoxidized with calcium boride or aluminum, were characterized by high first stages of creep. However, after about 1200 hr of test, the creep

Jan 1, 1952

By J. J. Beeson

Page I. PrimaRy MineRalization............................................ 356 1. Introduction..................................................... 356 a. Scope of Work............................................... 356 6. Acknowledgments............................................ 357 c. The Bingham Mining District.................................. 357 d. General Geology.............................................. 357 e. The Utah Copper Mine....................................... 376 f. Field and Laboratory work.................................... 376 2. The Quartz-Monzonite.............................................. 377 3. The Pegmatite Veins.....:.•..............................:........ 378 4. The High-Temperiture Veins.........................-.............:379 5. The Early Hydrotherma! Period.:......................&apos;............ 380 6. The Late Hydrothermal Period................................:.... 385 II. Seconuabx EnricuMENT............................................. 386 . 1. Author&apos;s Note;..... ;............................................ 386 2. Factors Governing Enrichment.....................................: 387 3. The Enrichment.................................................... 387 4. The Covellite Enrichment.; .:; ; : .:. :..:.............:................ 388 a. The Capping above the Covellite Ores:....:....................... 388 b. Conclusions Drawn. from a Study of the Capping and the Covellite ; Ores....,.............................................:.....,.&apos; 392 c. Covellite Enrichment at Depth......:......................... : : 392 5. The Chalcocite Enrichment...................................... ; 394 a. The Carbonates in the Capping above .the Chalcocite Ores...:..: .. 394 &apos; b. The Formation of Chalcocite..:.:. :......:..&apos;...........,......&apos; 394 . 6. Secondary Chalcopyrite and Bornite.............................i ..., . 395 111.- Conclusions as to the Formation.oF the ImpoRtant Sulphides in the Disseminated ORes........................................,.......... 400 I. Primary MiNeRalization 1. Intrdtiction a. Scop. e .of Work.. first part bf, this paper deals with the country rock, its pegihatitic, pneumatolytic&apos;, and hydrothermal altektions; also, the effect of magnetite on the deposition of the primary chalcopyrite and pyrite.

Jan 1, 1916

By R. McDonald, B. C. Maine

CERRO&apos;S power system consists of three main hydroelectric plants and one steam-electric plant. These are located on the eastern slope of the main Andes range at altitudes between 12,000 and 13,000 ft. The hydroelectric group utilizes the watershed which extends for about 150 kilometers south from Cerro de Pasco, divided into two catchment areas which lie adjacent. The northern area serve,, the medium-head plant of Mal¬paso. while the southern area provides for the high-head plants at Pachachaca and Oroya. The rainfall, as registered at the rain gauging stations of the three hydroelectric plants, averages 33 in. per year; all these stations are subject to the same hydrological conditions, and the bulk of precipitation occurs between October and March. Rainfall during the dry season, April till September, has no appreciable effect on the total annual runoff. Table 1 shows the storage capacities of the main reservoirs of the hydroelectric group. The four plants are tied together electrically by a 50-kv. transmission network, the system being 3-phase 3-wire at 60 cycles with a solidly grounded

Jan 1, 1945

By H. W. McCue, Henry Rogatz

Oil.—In the Texas Panhandle, 502 oil wells were drilled during the year 1940, with a total daily initial production of 139,187 bb1.—that is, 137 more oil wells drilled than in the previous year, with an increase in total daily initial production of 8219 bbl. The total daily potential of the field on Dec. 31, 1940, as determined by the Texas Railroad Commission, was 1,375,502 bbl., an increase of 30,825 bbl. over the previous year. On Dec. 31,1940, a daily allowable of 85,050 bbl., which was a decrease of 35 per cent over 1939, was assigned to the field to be produced from 4788 wells. The total amount of oil produced for the year was 26,788,590 bbl., making a cumulative total of 378,960,728 bbl. during the past 19 years. No new oil-producing acreage was discovered. Gas.—During the year, 92 gas wells were drilled, having a combined open flow of 2,402,900.000 CU. ft.; that is, 6 more than the number of wells drilled in 1939, with an increase in the open flow of 204,900,000 cu. ft. per day. The gas production for the year was 670,435,112,000 CU. ft., and the total gas removed from thc ground during

Jan 1, 1941

By Henry Rogatz, H. W. McCue

Oil.—In the Texas Panhandle, 502 oil wells were drilled during the year 1940, with a total daily initial production of 139,187 bb1.—that is, 137 more oil wells drilled than in the previous year, with an increase in total daily initial production of 8219 bbl. The total daily potential of the field on Dec. 31, 1940, as determined by the Texas Railroad Commission, was 1,375,502 bbl., an increase of 30,825 bbl. over the previous year. On Dec. 31,1940, a daily allowable of 85,050 bbl., which was a decrease of 35 per cent over 1939, was assigned to the field to be produced from 4788 wells. The total amount of oil produced for the year was 26,788,590 bbl., making a cumulative total of 378,960,728 bbl. during the past 19 years. No new oil-producing acreage was discovered. Gas.—During the year, 92 gas wells were drilled, having a combined open flow of 2,402,900.000 CU. ft.; that is, 6 more than the number of wells drilled in 1939, with an increase in the open flow of 204,900,000 cu. ft. per day. The gas production for the year was 670,435,112,000 CU. ft., and the total gas removed from thc ground during

Jan 1, 1941

By R. G. Hite, R. G. Rowe

The Crandon deposit, located in northern Wisconsin, is a 65.8 million ton Precambrian volcanogenic massive sulfide deposit which averages 1.4% copper and 5.8% zinc. The deposit is classic in origin, mineralogy and shape. Comprehensive understanding of the geology of both the deposit and the project site has been fundamental to the credibility and success of project feasibility studies and regulatory permit preparation. Mine development in the current investment and regulatory climate requires thorough and timely application of geologic tools. From 1977-1980 geologic activities were focused on the typical objectives of orebody delineation, reserve estimation, depositional geology, and general site investigation. Results from these programs formed the basis for the project&apos;s preliminary feasibility studies. Since 1981 further geologic investigations have provided criteria for project design, site management, and operational permitting. Activities have included mine entry position definition drilling, developing geostatistical reserve modeling, large diameter (150 mm) core drilling for mill pilot samples, rock mechanics testing, and evaluation of the glacial overburden/deposit geohydrology for computer simulation.

Jan 1, 1984