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By Vsevolod Krivobok

IT is generally recognized that "low temperatures" have a definite effect on the properties of metals and alloys. Furthermore, it is also generally understood that the effect is decidedly adverse. The possibility that the same low-temperature treatment might be employed for the purpose of improving certain properties of the .alloys has received less attention until recently, and the experimental and theoretical knowledge consequently is meager. The effect of low temperatures may be studied in two ways: by studying such properties as tensile strength, hardness, impact resistance, etc., at low temperature, and by studying the properties of alloys at room temperature after these alloys have been subjected to a low-temperature treatment. Even in the latter case, certain properties will differ materially from the same properties obtained on identical material but without cold treatment. In other words, subjecting alloys to cold treatment results in an irreversible change in mechanical properties. Changes of this character are usually indications of the appearance of a new phase or phases, and would be likely to occur in alloys which, either by virtue of their composition or by heat treatment, are retained at room temperature in a metastable condition. Consequently, studies of the effect of low temperatures logically should be conducted from the physicochemical point of view, since the results of such studies not only would furnish metallurgists with interesting theoretical data but would clearly indicate the classes of alloys that would hold promise of improvement, and, possibly, of new applications. As the present investigation deals with chromium and chromium-nickel alloys of iron of the stainless variety, it has been thought desirable to present the data concerning low-temperature properties of these alloys, available from the most recent and most comprehensive work of H: S. Russell.' A summary, of these data is given in Table 1. The data are confined to a limited number of alloys of the type dealt with in the present

Jan 1, 1931

NEW MEMBERS The following list comprises the names of those persons who became members during the period Nov. 10, 1916 to Dec.10, 1916. BARNSDALL, THEODORE N., Treas. & Mgr., Highland Gas Co., 24 West Corydon. St., Bradford, Pa. BEASLEY, FRED E., Asst. Supt., Copper Refinery, Consolidated Mining & Smelting Co., Trail, B. C., Canada., BREWSTER, THOMAS T., Vice Pres., Gen. Mgr., Mt. Olive & Staunton Coal CO., 1012 Federal Reserve Bldg.,-St. Louis, Mo. BRINDLE ARTHUR ST. C.... Mining Recorder's Office, Trout Lake, B. C., Canada. BULLOCK, Harry E., Pres Kentucky-Jewel Coal Co., Lothair, Ky. BUTLER, PERCY BENNETT, Mine Operator :..P. 0. Box 335, Joplin, Mo. BUTLER, ROBERT S Supt., Three Johns Mining CO., ,Joplin,.Mo. CABOT, Godfrey, L., Carbon Black Maker, Gas Engr., 940 Old South Building Boston Mass.

Jan 1, 1917

By Howard Eavenson

The data given in the paper were collected to furnish an idea of the amount required in various operations of bituminous mining to produce a ton of coal, the plants selected being well-managed ones. With these are included some figures compiled from U. S. Coal Commission's report showing the average amount of labor in various classes of mines. THE information contained in the following paper was collected at the request of the U. S. Coal Commission, and is, published with the permission of that body and of the various companies furnishing the data. For obvious reasons, the names of the companies are not given. No data were gotten from States south of Virginia or west of the Mississippi River. The data about the amount of labor, in man-hours, required in producing a ton of bituminous coal have been collected with the idea of showing what is being done at some well-managed plants, and not to show the average amount required by all mines, which undoubtedly is considerably higher than the average of the figures shown.* Almost all of the figures were supplied by the various companies in reply to a questionnaire; when they were obtained from other sources the company was asked to verify them. On account of the amount of work required, the data were only requested for one or two months for each plant, and the figures represent in each case a month when the car supply was good and the work was practically steady. In the case of most of the West Virginia and Kentucky mines, these conditions were best met in May and June, 1922. The mines for which the figures are given are arranged by states and as to whether the mine operates under union or non-union or open-shop conditions. The union mines listed are generally considered to be as well-managed as are the non-union ones. The production per month in a few cases includes the amount of slate which is loaded and hauled out of the mine, as of course this requires nearly as much labor per ton as does the coal. These cases are noted:

Jan 1, 1924

"In the spring of 1927, six members of the American Institute of Mining and Metallurgical Engineers met for dinner at the Chemists' Club in New York to discuss the possibility of setting up a committee within the Institute to further the current interest in the science of steelmaking. Attention' to this subject had been crystallized by a symposium held by the Faraday Society in 1925. ' After a prolonged discussion, ranging from thermodynamics to slag conditioning, it was decided to approach the Institute with the request that a standing committee on "The Physical Chemistry of Steel Making" be set up. This committee proposed to promote scientific and practical papers on the subject, and was designed to cooperate with the Open Hearth Committee of the Institute in bringing scientific developments to the attention of open-hearth operators throughout the country... . "As the life of the [Physical Chemistry of Steelmaking] Committee lengthened and general interest in the technical phases of steelmaking grew, it became evident that there was a distinct need for a book that might serve the open-hearth interests to better advantage than standard texts whose scope is necessarily wide and whose detailed exposition of the open-hearth process is, therefore, somewhat limited. With this thought in mind, the Committee, after some years of consideration and debate, embarked on the venture of writing a manuscript on `Basic Open Hearth Steelmaking'." The foregoing paragraphs, taken from the introduction by C. H. Herty, Jr. to the first edition, well describe the circumstances which led to the publication of "Basic Open Hearth Steelmaking" in the spring of 1944. The book consisted of nineteen chapters contributed by twenty-three authors and edited by the staff of Alloys of Iron Research and T. S. Washburn, B. M. Larsen, and J. S. Marsh with Frank T. Sisco as consulting editor. The Engineering Foundation and the Open Hearth Steel Committee of the Iron and Steel Division, AIME, made financial grants; steel companies and other organizations supported the publication by contributing time and expenses of staff members in their capacity as authors or editors. The volume was sponsored by the Seeley W. Mudd Memorial Fund and appeared under the

Jan 1, 1951

By L. C. Brown, J. S. Kirkaldy

AS part of a program to investigate the diffusive properties of dilute ternary austenites, we have made a determination of the effects of cobalt on the activity of carbon in y iron. Samples of pure iron and Fe-Co alloys were equilibrated at 1000°C in controlled CO-C02 atmospheres, following the procedure of R. P. smith.' The 0.010-in.-thick samples were analyzed for carbon by microcombustion analysis2 to give a set of isoactivity curves. The latter were converted to activity-coefficient (standard state at infinite dilution) plots by combination with Smith's data' for the activity of carbon in pure iron measured in a CO-C02 mixture. Table I shows the composition of the base alloys used, while Fig. 1 shows the experimental results superimposed on a set of curves generated by the relation In the notation of Wagner,' the interaction parameter is the second coefficient on the right, Eq. [I] adequately correlates the experimental points for those alloys which were prepared from electrolytic iron by arc-melting (2,4, and 7 pct Co). The results for the 10 pct Co alloy (supplied by Crucible Steel Co.) do not correlate with the others. In fact, the experimental points for this alloy correspond to an interaction parameter of It is possible that the interaction parameter is a function of concentration for large cobalt additions, but we are inclined to attribute the discrepancy to the presence of a significant amount of aluminum added to this alloy for deoxidation purposes (Table I). Preliminary measurements for the system Fe-C-A1 have indicated an interaction parameter of Which implies that the effect of aluminum in solution on the carbon activity is sixty times greater than the effect of an equal weight percentage of cobalt. These observations cast some doubt on the precision of the results of Chandhok, Hirth, and Dulis who used this same 10 pct alloy for their experiments, obtaining an interaction parameter of E = 2.2. There is considerable doubt as to the activity of a plane Fe-C system. Using a CH4-Ha mixture, Smith obtains cg = 6.1 for the effect of carbon on the activity of carbon in austenite, rather than the value of 8.9 given in Eq. [I]. The use of CHa-Ha mixtures has recently been questioned by Kaufman, Radcliff, and cohens who state that there is some possibility that other hydrocarbons are formed. Fortunately, the determination of the interaction parameter is not sensitive to the coefficient of Nc. For example, using the CHI-H2 results we obtain a value which is almost the same as that obtained using the CO-CO, results. The authors wish to thank Mr. E. J. Dulis of the Crucible Steel Co. of America for supplying us with samples of the 10 pct Co alloy used in their original work. Financial assistance from the American Iron and Steel Institute is gratefully acknowledged.

Jan 1, 1963

By S. Korman, S. B. Tuwiner

Chalcocite flotation is affected by agitation intensity during conditioning. Sodium sulphide in minute quantity may activate or depress, depending on conditions. Oxygen is a depressant while oxygen and sulphide neutralize each other by re-action at the mineral surface. Diffusion across a stagnant film at the surface governs reaction rates, while film thickness is reduced upon increase of agitation intensity.

Jan 2, 1950

By Benny Langston, Frank M. Jr. Stephens

IN recent years much attention has been given to recovery, treatment, and disposal of dusts discharged into the atmosphere from operations of industry. Considerable data has been accumulated on both operational1-4 and design5,6 of dust-collector equipment for commercial installations. On the other hand, there is almost no published data on design and construction of small-scale equipment to handle dust problems that arise in the ore-dressing laboratory. Dust-collection equipment such as multiclones, single-cyclones, scrubbers, chemical and mechanical filters, settling chambers, and electrostatic separators has proved its efficiency for collecting dust in industry. In the laboratory, however, the engineer is faced with the problem of collecting small quantities of dust, inexpensively, without diverting the major effort from the metallurgical problem to the problem of collecting dust produced by the process.

Jan 8, 1954

By Edmund B. Kirby

This meeting marks the point at which the long-standing dissatisfaction with the mineral-land laws, the innumerable protests against them, and the many isolated efforts to obtain relief, have developed into a general movement for their revision. That part of the mining industry which is affected by these laws has three general organizations which are able to speak for it: the American Institute of Mining Engineers, the Mining and Metallurgical Society of . America, and the American Mining Congress; all of which are represented in this meeting. In the series of able and thoughtful papers presented here, prominent men have discussed the evils of the present laws and some of the reforms which should be made in them. We all appreciate fully the ultimate value of these studies; but we are also painfully aware of the fact that discussion of this kind has been going on for a quarter of a century without any other effect than a steady increase in the mass of printed records stored on library shelves. In order to get any practical result we Gust induce an indifferent government at Washington to act, and to do this we must unite in pushing some practical plan whereby it may act in a simple and effective way and with the least possible amount of criticism or opposition. The actual question before us is not whether the mining laws are bad; for their evils and absurdities are not only beyond discussion but also beyond the resources of a temperate and dignified vocabulary. It is not what particular changes ought to be made; for it is premature to make . specific recommendations until there is some one to listen to them. Moreover, we all know that there are wisdom and experience enough available, and awaiting that time, for the creation of a code which would be a model to the mining world. The practical question now is, how to obtain the revision; and since the American Mining Congress has of late restricted its attention to this phase of the problem I wish as one of its representatives here to present its views upon the matter.

Jan 1, 1915

By K. A. Jackson, J. D. Hunt

The discussion by Tammann and Botschwar of the transition from eutectie grouth to denrdritic plus eu-tectic growth is reviewed and applied to metallic eutectic systems. Using expevimental data on the geowth rate of the Pb-Sn eutectic, and an extrapolalion of dendritic growth rate in tin and Sn-Pb alloys , qlcantitatice prerlictiotls of the extent of the eutectic region in tin-vich Sn-Pb alloys are made. There are no experimenta1 measuvements available for detailed comparison with these predictions. EUTECTIC structures form over a small range of compositions. The theory of lamellar growth presented by Jackson and Hunt' indicates that it is in principle possible to have eutectic growth over almost the complete range of compositions between the two solidus lines. This does not occur in practice. Alloys far from the eutectic composition grow dendritically followed by a eutectic as shown in Fig. I. The transition from a eutectic to a dendritic plus eutectic interface cannot be predicted from constitutional undercooling arguments because constitutional undercooling always exists ahead of the eutectic interface.' Reasonable predictions can, however, be made using arguments originally put forward by Tammanl. and Botschwar.3 These and later workers'"*6 carried out extensive experimental investigations of the extent of the eutectic range in organic materials. They concluded that the structure formed, eutectic or dendrites plus eutectic, depended on which structure grew faster at the given undercooling. This is, of course, equivalent to the structure which grows with the smallest undercooling at a given growth rate. In this paper, we will discuss these ideas briefly and then apply them to predict quantitatively the range of eutectic growth in tin-rich Pb-Sn alloys. The temperature dependence of the growth rates of dendrites and eutectic for a typical metal alloy of eutectic composition is shown schematically in Fig. 2(a). The growth rate for the eutectic increases more rapidly with undercooling than those of the dendrites because of the short diffusion path maintained in the eutectic, see Fig. 1. For an alloy off the eutectic composition on the A-rich side, the growth rates shift as shown in Fig. 2(b). The liquidus temperature of the a phase increases, that of the 3 phase decreases, and the temperature of zero growth rate for the eutectic does not change. The curves, particularly the dendritic ones, change shape as well, but for our purposes the principal effects occur because of the change in liquidus temperatures.3-6 In an isothermal system, only a dendrites will grow above TE, Fig. 2(b). If the temperature is below TE, and both phases have nucleated, a dendrites will grow ahead of the eutectic at

Jan 1, 1968

By T. E. Ockershauser

The Southwest Antioch Oil Field located in T2&3N - R2&3W, Garvin County, Okla., was discovered in February, 1946, by The Globe Oil & Refining Co. and The Vickers Petroleum Co. at their Melinda Gibson No. 1. Oil production was encountered at a depth of 6,525 ft in 14 ft of lower Pennsyl-vanian sandstone. The producing sand, locally called the ."Gibson" or "Third Deese," is a sand bar deposit strung along the west flank of the Pauls Valley uplift in a northwest-southeast direction. The oil reservoir is defined to the east by the edge of sand deposition along the uplift and to the west by the gradation of sand into shale. Within the Antioch Unit, the sand dips from 150 to 400 ft per mile southwesterly and has a pay thickness varying from 10 to 55 ft and averaging 28 ft. Several areas of Gibson production have been developed, including the Katie pool on the south, the Elmore Area of the Southwest Antioch Gibson Sand pool. the Southwest Antioch Gibson Sand pool proper, the Southwest Maysville pool and the New Hope pool on the north. Production extends over a belt 22 miles long by about two miles wide and is continuous except into the Katie and New Hope pools. It appears that drilling will soon prove these intervening areas productive. To March 1, 1950, approximately 18,000 acres have been developed with 450 Gibson wells. It is likely this count will ultimately reach 32.000 acres with 800 wells. RESERVOIR The natural production of oil from the Gibson reservoir is primarily due to solution gas expansion though gravity also plays a part. There is no indication of water drive or evidence that an initial gas cap existed. Gibson oil has a stock tank gravity of 43" API and was saturated at the original reservoir pressure of 2.925 psi. It contained 1,3440 cu ft of gas per bbl in solution and had a high shrinkage of 70 per cent. Connate water amounts to 15 per cent. Reservoir temperature is 130°F. Porosity averages 15.5 per cent and permeability ranges from less than one md to over 1.000. Based on meacurement of 400 core plugs from 15 wells, 78 per cent of the permeabilities fell within the 10 to 1,000 md bracket and averaged l67. Primary oil recovery is estimated at 140 bbl per acre-ft or 22 million bbl for the present 137-tract unit. Due to unitization

Jan 1, 1951

By Claude P. Heiner, Carl S. Westerberg

OBSERVATION of the clinkering action of coal from the Castle Gate D seam in underfeed stokers over a period of years has given rise to the present investigation of the effect of bony coal on clinkering. Some very costly examples of slagging clinkers in particular cases have been of especial interest to the authors. In such cases coal analyses and ash-softening and fluid temperatures have been found of little value. In general, it was noted that slagging was accompanied by a somewhat higher ash content of the stoker slack, and the suspicion naturally arose that foreign matter was the troublemaker. One would naturally suspect bony coal and rock impurities because of their occurrence and prevalence within the seam and the relative absence of sulphur or other impurities in the coal mined. The test results given herein indicate that the concentration of the bony coal and rock impurities in the coal determines the clinkering tendencies of the ash during combustion. CASTLE GATE D SEAM Extending from the Utah-Colorado line near Grand Junction, Colo., westward to Greenriver, Utah and thence in semi-circular form north and westward to Castle Gate, and from there southward to Mt. Hilgard in central Utah, is a line of nearly perpendicular cliffs, composed of interbedded massive sandstone and shales, making up the coal-bearing horizon of the Mesaverde formation of Upper Cretaceous age. The cliffs face roughly concentrically toward the south and southeast and the strata, with conformably enclosed coal beds, gently dip away from the face of the cliffs and at right angles to their front line. Back of these cliffs the mountain masses rise to an altitude of from 8000 to 10,000 ft. above sea level. Stretching away from their foot is a great shale plain, on which the towns are situated and over which the railroad lines and highways run. The Castle Gate mines enter the coal beds at their outcrop; the workings extending within a particular coal bed away from the outcrop and under the mountain mass back from the cliff line (Fig. 1). Throughout the Mesaverde formation in the Castle Gate general area, there are from two to five workable coal beds. Usually not all of these are coincidentally of workable size and merchantable quality throughout any given large tract. In the Castle Gate mine area, the base of the Mesaverde horizon and coal measures is marked by a massive, cliffmaking, gray sandstone bed 6o to 8o ft. thick. Locally this is referred to as the "Castle Gate sandstone floor." Frank R. Clark, in U. S. Geol. Survey Bull. 793, designates it as the "Aberdeen sandstone." At Castle Gate the various coal beds are designated by the letters A, B, C, etc., commencing with the lowest bed. Fig. 2 is a graphic generalized vertical section, compiled from physical exposures

Jan 1, 1941

By Frank D. Hoyt

BY far the most conspicuous of the Pennsylvania slate districts is that extending from the New Jersey line at the Delaware Water Gap westward almost to the Schuylkill River. This covers parts of three counties in east-central Pennsylvania: Northampton, Lehigh, and Berks. The most important development, both in geographic size and product importance, is in Lehigh and Northampton counties. The greater part of the region is underlain by only one formation-the Martinsburg, consisting of slates, clay slates, and sandy shales, all of the Ordovician period. The slate-bearing Martinsburg formation is underlain by Cambro-Ordovician limestones. Immediately overlying the Martinsburg formation is the Tuscarora quartzite of the Silurian period. The Martinsburg formation itself is divided into three distinct divisions, termed simply: the upper, the middle, and the lower members. Commercial slate has been extracted from all of these members, but the formation of greatest importance is the upper member, representing 2600 ft of the total formation thickness of nearly 11,000 ft. The upper member is commonly referred to as the "soft slate" and consists of three facies: 1) beds of blue-gray, very sandy, almost quartzitic slate, in many places, approximately a medium-coarse sand- stone with calcareous cement; 2) blue-gray sericitic slat-the dominant rock type of this member-with occasional chloritic beds; and 3) dark gray or virtually black, highly carbonaceous beds, referred to locally as "ribbons."

Jan 8, 1958

By Colin G. Wilson

This paper considers the heavy liquid laboratory tests used to determine the amenability of a potential ore to the heavy media process. The results of the laboratory testing are correlated to actual plant performance and establish design parameters for the heavy media process. These parameters are used in the development of the metallurgical flow sheet and in the sizing of equipment in the metallurgical plant design.

Jan 1, 1978

By Fred E. Beasley

Metallurgists have, in the last ten years, overcome many difficulties of high zinc in lead blast-furnace slags. This problem was brought to the front at the close of the war, by the price obtained for lead and the high cost of labor, fuel, and flux. The Port Pirie plant of the Broken Hill Associated Smelters, Australia, early in 1919 had increased the zinc oxide in its blast-furnace slags from 13.5 to 20 per cent., at the same time reducing the iron oxide in the slag from 33.5 to 25.6 per cent. These results were obtained by the addition of 10 to 12 per cent. granulated slag to the roaster charge, improved conditions of the crushing, mixing, and roasting of the constituents of the sinter. By experiments and improvements, the practice at this plant has developed a normal slag that carries 22 per cent. zinc oxide, and at times runs as high as 33 per cent. zinc oxide, with only slight furnace trouble. The granulated slag is used not only as a diluent to the sulfur in the roaster charge, but on account of its value as a slag-forming material and the physical properties it imparts to the finished sinter. The ore is mixed with flux and given a double roast. All the first roasting is by sintering with the Dwight & Lloyd machines. The final roasting is performed partly by Dwight & Lloyd machines and partly by H. & H. pots. The charge to the blast furnace consists chiefly of the final sinter, slag shells, siliceous and non-bearing sulfur lead ores. High blast and ore columns are the practice. The greatest care is taken to obtain in the final sinter as low a sulfur content as possible. Attracted by the success of the Port Pirie plant, The Consolidated Mining & Smelting Co. of Canada, at Trail, B. C., in 1920 treated its crushed primary sinter with about 15 per cent. granulated slag. The Trail smelter at this time was short of ore and a large part of the charge to the roasters consisted of the zinc-plant residue having the following analysis: 12 to 16 per cent. lead, 12 to 16 per cent. zinc, and 25 to 30 per cent. iron. The lead in the final sinter was low and the physical condition was so bad that all the sinter had to be screened before it could be charged to the blast furnace. Also it disintegrated on being trammed and dumped

Jan 1, 1925

By P. B. Knuckey, D. Littleford

The Kalengwa mine, situated in a remote area of Zambia in Central Africa, has presented some unique problems to the planners engaged in developing the deposit. This small, high grade copper deposit contains some 1,688,000 tons of ore at a grade of 9.3% contained copper. Of this 362,000 tons is classified as high grade ore at 27.2% Cu, the coarse fraction of which can be fed directly to converters; 733,000 is classed as intermediate grade ore averaging 6.3% Cu, and 593,000 tons classed as low grade ore containing 2.1% Cu. The geology of the deposit and the establishment of the mining operation is fully described. A concentrator is being built at Kalengwa to treat the high grade fine product, intermediate, and low grade ore, whilst the coarse high grade ore will be trucked to the Copperbelt smelters for direct smelting. Details of metallurgical processing are given. The decision to truck the coarse high grade ore to the smelters on the Copperbelt necessitated the construction of a new 200-mile road, the setting up of a fleet of heavy ore transport trucks and associated equipment. The remoteness of the area from established communication facilities on the Copperbelt necessitated the provision of radio communications between Kalengwa and the head office at Kalulushi, and the establishment of a regular mine air service. The paper also describes the training of an unsophisticated local population in the operation of heavy plant and machinery, the establishment of the township, and the provision of health services.

Jan 1, 1972

By J. B. Cohen, M. B. Beaver, R. J. Black

RECENT investigations have shown that face-centered cubic metals may deform by twinning. Blewitt, et al' found that at 4.2"K the mode of def~rmation of single crystals of copper changed at large strains and markings formed on (111) planes. Later they- emonstrated by X-ray diffraction and metallography that the markings were twins and showed that favorably oriented single crystals of copper deformed by twinning at 78°K. They also observed twinning in silver and gold deformed at 4.2 and 78°K. Wagner3 obtained evidence for twinning from the peak shape of diffraction lines of silver cold-worked at 78°K, but twins small enough to cause such effects are not likely to be detected metal-lographically. In the work reported here lamellar structures were observed in deformed silver-gold alloys. They appeared to be mechanical twins, but metallography could not establish this conclusively. Their tendency to form depended on strain rate, temperature and composition. Specimens of silver-gold alloys (0 to 83 wt pct Au) were deformed plastically. One set was worked by hammering under liquid nitrogen, at room temperature and at intermediate temperatures. Another set was compressed slowly in liquid nitrogen to the same reductions as those produced by hammering. Tensile specimens (0.015 x 0.120 x 1.5 in.) of various compositions and approximately equal grain size (0.011 to 0.016 cm) were tested at -195°C and at room temperature. In microsections of all specimens deformed by hammering at —195°C thin lamellae appeared, Fig. 1. They were aligned in definite directions in each grain. In some grains they had two orientations. Where lamellae intersected, a displacement was apparent. Near the center of the left margin of Fig. 1 shear has taken place beyond the fully developed intersecting lamella. Many lamellae resembled Neumann bands in alpha iron. They were parallel to one side of triangular etch pits in the matrix (as in Figs. 1 and 2). The individual lamellae were narrow and had little substructure. This suggested that they did not result from concentrated local slip. The shape of etch pits within the lamellae differed from that of pits in the matrix, as can be seen in Fig. 2; this indicated a difference in orientation. Specimens slowly deformed at —195°C contained regions in which the lamellae were clustered. In these specimens some lamellae were bent and presumably had formed before the termination of the deformation. Structures of greater width than the lamellae were also seen.4 More lamellar structures formed on impact than during slow compression to a given reduction. This was true of all compositions. The structures became less abundant with increasing temperature of deformation. None was observed after extension to fracture at room temperature, but they could be pro-

Jan 1, 1959

By R. W. Smith

A study has been made of the crushing and grinding circuits by the Portland Cement Association in nine cement plants. Five of the plants used the wet process and four, the dry method. Both raw and clinker grinding were studied in the four dry processing plants. The raw materials used varied considerably from plant to plant. Actual power consumption data were obtained for the majority of the grinding mills in these plants. Previously representative raw and clinker samples had been obtained from the nine plants, and Bond1 and Hardgrove2 grindability tests were run on these samples. All pertinent data concerning the grinding mills, such as mill size and speed, ball charge size and weight, size distribution of feed, and discharge materials were also obtained. Thus it became possible to calculate the actual horsepower used by the various mills, and to compare this figure to the theoretical horsepower as calculated by several different methods.

Jan 4, 1961

Illinois Mining Institute, 224 South Michigan Ave , Chicago, Ill. B. E Schonthal, Secretary. In 1929, 1930 and 1931, the Institute published the Proceedings of its meetings The volumes of the Proceedings are a record of the papers and discussions presented at the two meetings each year and deal with coal mining in Illinois. The Proceedings will be sent to those particularly interested on receipt of sufficient postage to cover mailing

Jan 1, 1933

By R. W. Raymond

The important question of the metallurgical value of the coals of the Rocky Mountains and the Pacific Coast is to be settled, of course, by practical experiment. Meanwhile, as I have had occasion to point out, the proximate analyses of these coals throws little light upon it, and is, indeed, likely to mislead the metallurgist, if he compares it with the results of similar analyses upon bituminous and semi-bituminous coals. With the view of showing how large a proportion of the material usually classed as(" volatile matters " consists of combined water, or oxygen and hydrogen presumably in chemical combination, I have collected a number of ultimate analyses from various sources, in the following tables. The numbered analyses in the first table are as follows: No. 1. Monte Diabolo coal—Analyst, H. S. Munroe, Col. School of Mines. 2. Weber Canon, Utah, " " " 3. Echo Canon, " " " " 4. Carbon Stat'n, Wyoming, " " " 5. " " " " " 6. Coos Bay, Oregon, " " " 7. Alaska, " " " 8. " " " " 9. Canon City, Colorado, " Dr. T. M. Drown, Philadelphia. 10. Baker Co., Oregon, " " " 11. Blockcoal,SandCr'k,Ind., " Prof. E. T. Cox. This table affords some suggestive comparisons, to facilitate which a remark or two, explanatory of its construction, will be useful. In the ultimate analysis of coals, the proportions are frequently calculated (as, for instance, in the report for 1872 of Prof. Cox, State

By E. F. Adkins, R. W. Douglas

The variation of the spectral emissivity of osmium and ruthenium with temperature can be expressed by the following relations: DURING a study of the sintering characteristics of osmium and ruthenium, discrepancies in the previously accepted melting points of the metals were noted. The melting temperatures had not been measured at the time of the work, but were estimated in the literature as 2700°C for osmium and 2450°C for ruthenium.' A recent investigation by Baird2 has shown the melting temperatures of osmium and ruthenium are 3000" and 2250° C, respectively. In the present work, osmium bars sintered at temperatures as high as 2900° C showed no evidence of melting, whereas ruthenium showed definite evidence of melting at temperatures as low as 2250°C. In view of the apparent discrepancies, the melting temperatures of both metals were determined. The spectral emissivities of both metals were determined as an aid to studies of the sintering characteristics of these metals. MATERIALS AND PROCEDURES The materials used in these studies were metal powders supplied by Englehard Industries, Inc., through the courtesy of The International Nickel Co. Analytical data from three laboratories, although not in complete agreement as to the purity of the material or the major impurity elements, indicated that the maximum impurity levels were 0.5 and 1.0 wt pct in osmium and ruthenium, respectively. The metal powders were pressed to 1/4 by 1/4 by 6-in. bars at 20Tsi using carbon tetrachloride as a lubricant. The pressed bars were presintered 1 hr at 1200°C after heating 1 hr at 400°C. The presintered densities of the several bars of the metals ranged from 65 to 80 pct of ideal density. Specimens were self-resistance heated in a vacuum sintering bell. Temperatures were measured with an L&N, disappearing filament optical pyrometer. True temperatures were read at the base of an 0.30-in.-diam, 0.150-in. deep hole drilled into the center of a presintered bar. Apparent temperatures were read from the surface of the bar adjacent to the hole. MELTING POINT DETERMINATION The melting temperature of the metals was determined as the temperature at which a slight additional increase in current through the specimen resulted in a reduced temperature at the base of the hole. The apparent reduction in temperature is a result of the liquid metal filling the hole, thus altering the black-body conditions. The melting points of osmium and ruthenium, based on three deter-

Jan 1, 1962