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By Junius D. Edwards, Cyril S. Taylor

Magnesium is the lightest metal used for structural purposes, for which reason perhaps more than usual interest is attached to measurements of its density. Although the density of solid magnesium has been det,ermined frequently, no measurements of the density of the liquid metal are available. Because of unusual experimental difficulties in measuring the density of the liquid, only a limited number of measurements of good precision were secured. The results, especially the value for the crystallization shrinkage, are of great interest in connection with the casting of the metal. A number of samples for these measurements were made available through the courtesy of the American Magnesium Corp. They were in the form of extruded bars 3/8 in- in diameter and several were of exceptional purity, as indicated by careful analyses. Table 1 gives the density values (at 20" C.) for magnesium of varying degrees of purity. The density was measured at room temperature by comparison of the weight in air, and when immersed in distilled water. The necessary buoyancy corrections were applied, so that the density could be expressed in absolute measure—grams per milliliter. The effect of the buoyancy of the immersed suspension and the surface-tension pull of the water upon the suspension were eliminated from the results by a preliminary weighing of the suspension immersed to the working depth. Great care was necessary to prevent the introduction of a significant error by the formation of gas bubbles upon the clean magnesium surfaces; these are sometimes very minute and easily escape observation. They may be detached by raising the specimen from the water and again immersing; this should be done just prior to completing the weighing. Their formation may be almost entirely prevented during a measurement by previously immersing the specimen in a solution of paraffin in petroleum ether. The thin film of paraffin remaining after the evaporation of the solvent prevents wetting of the magnesium surface by the water. In one such determination, the paraffin coating on a 22-gm. Specimen

Jan 1, 1923

By Paul F. Kerr

Uranium mineralization occurs in the footwall of the Sunshine vein from the 2900 to the 3700 level. Veinlets of uraninite associated with pyrite and jasper have been so extensively divided and recemented that units more than a few feet in length are seldom observed. The wall rock is St. Regis quartzite of the Belt series. The age of the uraninite, on the basis of isotopic analyses, is 750 t- 50, which agrees with geological data suggesting that phases of the Sunshine mineralization are pre-Cambrian.

Jan 5, 1953

By David G. Chedgy, Wen L. Chen, Bill S. Taylor

Theoretically the heavy medium cyclone is capable of cleaning raw coal from a top size of about 38 mm (1 1/2 in.) to a bottom size of about 200 mesh. With this idea, plants have been built recently using the heavy medium cyclone without desliming. The full size range down to zero is fed into the cyclone. Products + 28 mesh are removed in the normal manner on drain and rinse screens. The 28 x 200 mesh products are recovered separately from the magnetic separator tailings. Simplicity of flowsheet and plant operation coupled with the high efficiency of the heavy medium cyclone makes this a very attractive approach.

Jan 1, 1980

By Arthur F. L. Bell

Prior to 1908 the oil production in the State of California had been almost entirely a heavy fuel oil, with a high flash point, but changed within a short period to a large percentage of refining oil with a low flash, by reason of the heavy production of light oil coming in from the Santa Maria field, the Midway field, and the increased production of the Fullerton field. This is clearly shown in the following tabulation of California's pro- The bringing in of these high percentages of light oil with their dangerous low flash and the increasing demand for the refined products necessitated the devising of some cheap and efficient means of quickly separating the lighter elements either in the field or at the main distributing points; also it became necessary to remove the excessive percentage of water which many of the light oils carried in emulsion. Union Oil Co. Port Harford Plant Probably the first important attempt to top light oil in California by other means than the ordinary stills was tried about 1908 by the Union Oil Co., at its plant at Port Harford, San Luis Obispo County, with Santa Maria oils. The process was the invention of Hubert G. Burroughs who afterward obtained a patent for the process, No. 998,837, dated July 25, 1911. The apparatus used consisted of a series of 12-in. pipes mounted in units of three pipes, one above the other, the crude oil being admitted to the upper pipe and filling it about two-thirds of its

Jan 1, 1916

By M. Vallée

This case study compares the actual production figures for the No. I and No. 2 copper orebodies of the Société Miniére Louvem, Val d'Or, Quebec, with the preproduction estimates and a postmortem geostatistical estimation using kriging techniques. The deposits considered are small subvertical sulphide orebodies which were mined from August 1970 to April 1973, producing 648,000 tons at 2.04% Cu versus the 1968 computed reserves of 671,000 tons at 2.51% Cu (with 20% dilution), thus showing a 25% overestimation of the copper contained. The postmortem geostatistical estimation based on the same 44 D.D.H. intersections available in 1968, shows 2.24% Cu (no dilution), compared to 3.23% Cu (no dilution) given by the conventional section method. Block by block kriging techniques were used, but within the ore contours as determined by the geologist. In this case, Characterized like many sulphide deposits by highly dispersed sample values, geostatistical kriging techniques permit a more realistic estimation of the metal contained within a given volume, than the conventional methods which overestimate it. This study has been conducted by the Mineral Exploration Research institute (IREM-MERI) for SOQUEM, and is one of the few case studies released with all pertinent data. More postmortem of this kind are required for geologists and geostatisticians to improve their methods and their "batting average".

Jan 1, 1977

By John P. Bernardi, Ralph B. Hall

Past and present phosphate production in the central Florida phosphate district has been predominantly from the unique Bone Valley formation. As these lucrative reserves are depleted, production will shift to the Hawthorn formation in all areas, but particularly so within the southern extension, where vast potential reserves of low grade phosphates exist. Use of existing plants can be extended for some years by mining deeper into the underlying Hawthorn formation, and by mining previously ignored peripheral areas if erratic combinations of the two formations. Hawthorn Production, as compared to the Bone valley, will be characterized by lower grade; lower tonnage yield, lower pebble percent of product, higher mining ratios, higher slimes (- 150 mesh) content, and more complex mining and beneficiation problems. Geological control and more sophisticated operational procedure; will become increasingly more important as the lower quality reserves replace Bone Valley production.

Jan 1, 1981

By Donald Ofte, L. J. Wittenberg

The absolute viscosity coefficients and activation energies for viscous flow of bismuth, lead, and zinc are reported. The viscosities were measured in an oscillating cup viscosimeter from nearly 1000°C to within 1 deg of the melting point of zinc; 2 deg of the melting point of lead; and in the supercooled condition of bismuth, 9 deg below the melting point. Two methods of relating the change in the viscosity coeflicient with temperature were compared. From the plot of the logarithm of viscosity (77) as a function of reciprocal absolute temperature (1/T), the equations of the lines which fit the data are: AS a part of the Reactor Fuels and Materials Research program at Mound Laboratory, precise measurements of the physical properties of liquid metals are of interest because the desirability for a low vapor pressure liquid coolant in high-temperature nuclear power plants has focused attention on the properties of the liquid metals.' Also, a clearer understanding of the liquid metal state can be achieved when better measurements are available. For these reasons, the viscosity values of certain liquid metals have been determined. The viscosities of the liquid metals, bismuth, lead, and zinc are measured in an oscillating cup viscosi-meter. In this apparatus the liquid is sealed in a right-circular cylindrical cup which is attached to a torsion fiber so that the system forms a torsion pendulum. The damping effect of the molten metal upon the normal oscillations of the torsion pendulum is a function of the viscosity of the liquid. This method is advantageous because of the small amount of sample required (8 to 10 cc), the ease of remote operation of the apparatus in a vacuum system, and the containment of the liquid metal in a hermetically sealed, nonreactive, tantalum crucible. With the liquid metal sealed in the crucible, loss of liquid by vaporization and chemical reactions with atmospheric gases are prevented. Additionally, an absolute viscosity determination is obtained which avoids the sources of possible error in a relative measurement. The difficulties in a relative method include the repetitious cup calibrations, and the uncertainty inherent in the practice of calibration of the apparatus at room temperature and extrapolation to the high temperatures necessary for the investigation of most liquid metals. The oscillating cup viscosimeter was first described by Meyer in 1891.2 The first complete mathematical treatment offering an absolute measurement of viscosity with this type of apparatus was proposed by Andrade and chiong3 in 1936 for an oscillating sphere filled with a liquid. This solution was modified to include a right circular cylinder by Hopkins and Toye4 in 1950, and R. Roscoe5 in 1958. Roscoe's treatment for the calculation of the viscosity of a liquid at a particular temperature from the logarithmic decrement and period of oscillation of the torsion pendulum was used in this investigation. A detailed description of the method of calculating the viscosity from these measurements has been reported earlier.' This calculation has been programmed for the IBM 704 and IBM 1620 computers for expedition of the otherwise laborious calculations. APPARATUS The cutaway view of the apparatus in Fig. 1 shows the suspension system within the high vacuum enclosure. The low residual gas pressure. maintained between 1 x 10-4 and 5 X 10-6 mm Hg during a determination, avoided both air drag on the pendulum and

Jan 1, 1963

H. H. Bleakney (Dept. of Mines and Technical Surveys, Ottawa, Canada)— The work of Dr. Machlin and his colleagues at Columbia University is so scholarly that one hesitates to take issue with them. Nevertheless the writer feels compelled to enter a demurrer to the mechanism of intercrystalline cracking proposed in this paper. The principal obstacle to its acceptance is found in its preoccupation with purely mechanical influences and its disregard for the chemical effect of impurities. The writer believes that the destruction of metallic cohesion by concentration of impurities at the grain boundaries is a necessary and sufficient condition for the development of intercrystalline cracking; and he believes that discussion of the numerous mechanical explanations proposed should wait until some valid objection to the chemical hypothesis has been advanced. It is nearly twenty years since Gillett" drew attention to the possibility that the chemical influence of precipitation might be the cause of intercrystalline cracking. As early as 1935, Greenwood'" remarked that grain-boundary precipitation of impurities in lead appeared to promote intercrystalline cracking. Again in 1939, Scott commented as follows on a paper by Thielemann and Parker:'" "There are at least two familiar phenomena that can influence grain-boundary cohesion: 1) intergranular oxidation; and 2) grain boundary precipitation. An important consideration in this work, therefore, is to determine which, if either, of these factors is responsible for the low values of cohesive strength observed." In 1952. the writer presented evidence," some original and some abstracted, which indicated that in copper, silver, aluminum, lead and iron, intergranular cohesion was a function of the purity of the metal. In 1954 Glen, discussing a paper by Ridley and Tapsell14 indicated his belief in a precipitation mechanism for the intercrystalline embrit-tlement of molybdenum steel and suggested that with an absolutely pure metal it would be almost impossible to obtain an intercrystalline crack. This suggestion has

Jan 1, 1959

NEW MEMBERS The following list comprises the names of those persons who became members during the period Sept. 10, 1916, to Oct. 10, 1916. BLOOMFIELD, EDWIN CHARLES, Min. Engr., 1012 Standard Bank Bldg., Vancouver, B. C., Canada. BRINGS, HENRY, Min. and Met. Engr., Chief Engr., and Geol., Mollet-Mesrine, 1212 Mills Bldg., El Paso, Texas. CHASE, MARCH F., Vice-Pres., Commercial Acid Co., 1906 Boatmens Bank Bldg., St. Louis, Mo. CUMMINGS, ALVIN M., Asst. Mine Supt., Witherbee, Sherman & Co., Inc., Mineville, Essex Co., N. Y. DOUGLASS, GEORGE M., Genl. Safety Inspector, Amer. Smelt. & Ref. Co. 120 Broadway, New Fork, N. Y. EMRICH, CLARENCE T., Chief Chemist, Old Dominion Copper Min. & Smelt. Co., Box 1163, Globe, Ariz. GARDANIER, SUTTER ALBERT, Assayer, Mgr., Douglas Assay Co., Douglas, Cochise Co., Ariz.

Jan 10, 1916

By Benny J. Nelson

To obtain information on the effect of gallium upon the corrosion of magnesium alloys, tests were made on the commercial alloy AM52S (Mg-3 pct Al-1 pct Zn-0.2 pct Mn) and experimental

Jan 1, 1957

By J. S. Ross

OIL-FIELD waters enter into many underground problems with which the petroleum engineer has to deal. Whether the problem is one of infiltration or natural encroachment, it is always desirable to determine the source of the water before commencing repair or remedial work. The usual mechanical tests for determining the source of extraneous water in wells are slow and expensive. An excellent means for the identification of oil-field waters may be afforded by their chemical characteristics when the chemical character of waters from the various sands has been established, by careful sampling and analysis cautiously interpreted. In the Salt Creek field, Wyoming, a fairly high degree of efficiency has been attained in the controlof field operations by utilizing the information afforded by the analysis. All of the operating companies appreciate this means of identifying waters, with the result that water-sampling has become general practice. Most of the chemical work dealing with Salt Creek waters has been done since the laboratories of the Midwest Refining Co. and the U. S. Geological Survey, were established in the field; the former in 1922, the latter in 1924. A spirit of cooperation has existed between the company and the government personnel by which many of the data for this paper were made available.

Jan 1, 1928

By R. G. McQueen, E. G. Zukas

THE production of isotropic fine-grained ingot iron would be most useful since physical measurements associated with the elastic properties of iron are influenced by the size and orientation of the individual grains. This can be accomplished at present for small samples by established metallurgical procedures, but for large samples (in excess of 2 in. diam by 1 in. thick) it is virtually impossible to produce reasonably small uniform grains with random orientation. Such pieces can, however, be produced by impulsive loading followed by a suitable recrystallization treatment. The shock loading system employed is diagrammed in Fig. l. Here the 3/8-in. iron plate is accelerated by the plane-wave initiated high explosive charge through a 1 5/8-in. air space. Collision of this plate and the specimen of interest generates a shock wave in excess of 300 kbars which passes through the specimen. For this type of work it is not necessary to use machined parts: for example, the ingot iron pieces are saw cut from the billet so that they can be inserted in short sections of iron pipe. The recovered specimens are less distorted, however, if the air gap between the iron sample and pipe is filled with Woods metal. The dimensional changes resulting from this type of loading technique are minor, usually less than a 10 pct reduction in thickness. Compressive yield

Jan 1, 1962

By David Phillips, George Jura

WHEN Bridgman1 determined the volume-pressure relationships of bismuth to 100 kg Cm-2, he found two small volume discontinuities at 45 and 64 kg em-2. Probably every investigator in high pressures has determined the electrical resistivity of bismuth in this pressure range. Until Zeitlin and Brayman2 reported discontinuities in the resistance of bismuth at these pressures, no one had found resistance discontinuities

Jan 1, 1968

By Frank Doxey

Louis A. Turnbull (U.S. Bureau of Mines, Washington, D. C.)—This paper is a well-organized concise discussion of progress in mechanization at coal mines in Nova Scotia during the last 50 years. It shows the perseverance and resourcefulness of those responsible for the production of high-quality coal essential to steel production in the area. The development of the Dosco miner and its use in longwall mining at the Sydney

Jan 1, 1955

By Hamish D. S. Miller

Currently the underground potash mines in Canada extract about 40% of the available ore, leaving the other 60% behind in the form of stabilizing pillars. The presence of water in the overlying formations requires that any disturbance due to mining be such that no water will enter the workings. This paper deals with the factors that influence the stability of the rock surrounding the mine excavations and looks at the effects of these factors when a system of increasing the extraction is considered.

Jan 1, 1983

By T. G. Decker, A. F. Witt, A. M. Gaudin

The historical development of the concept of contact angle hysteresis is reviewed. The measurements of contact angles reported in literature have all been made under static conditions. For the measurement of dynamic advancing and receding contact angles, four methods are described together with an evaluation of their precision. Three of these methods were adapted from devices already used for the measurement of static contact angles. The fourth method uses a new principle and apparatus and is the most accurate. While the relationship between surface tensions and the contact angle was extablished as early as 1805 by T. Young,' it was only in 1890 that the existence of contact angle hysteresis was reported by Lord Rayleigh. His observations, however, remained almost unnoticed. With the invention of froth flotation, the contact angle and its behavior became the subject of investigation. In 1907, L. Sulman and collaborators investigated the cause of discrepancies between recorded values of contact angles. They found that certain variations existed in most cases, but that definite maximum and minimum values of contact angles are obtainable. The difference between the maximum and the minimum contact angle in a given system was termed "hysteresis" by Sulman. First attempts to explain hysteresis were made by E. Edser. In the following years extensive studies of contact angles in various three-phase systems

Jan 1, 1963

By H. E. T. Haultain

The study of rock crushing or grinding in tube-mills is difficult on account of the large size of the units employed in the field and the large number of variables entering into the problem. Three or four years ago, in the laboratory of the Department of Mining Engineering of the University of Toronto, a serious effort was commenced to study the matter under laboratory conditions. Experiments were carried on in a cylindrical tube-mill 18 in. long and 12 in. in diameter, inside measurements,

Jan 1, 1923

By H. E. T. Haultain

The study of rock crushing or grinding in tube-mills is difficult on account of the large size of the units employed in the field and the large number of variables entering into the problem. Three or four years ago, in the laboratory of the Department of Mining Engineering of the University of Toronto, a serious effort was commenced to study the matter under laboratory conditions. Experiments were carried on in a cylindrical tube-mill 18 in. long and 12 in. in diameter, inside measurements,

Jan 1, 1923

By D. A. Crerar, R. L. P. Kleinmann, R. R. Pacelli

A bacterium, Thiobacillus ferrooxidans, is of prime importance in the formation of acid drainage from pyritic material. Above pH 4.5, T. ferrooxidans increases initial acidification; below pH 4.5, it allows acidification to continue by oxidizing Fe2 +. Below a pH of approximately 2.5, the activity of F3+ is significant and results in steady-state cycling between oxidation of pyrite by Fe3 + and bacterial oxidation of Fe2 +. Laboratory and field tests demonstrate that inhibition of T. ferrooxidans by controlled release of anionic detergents can inexpensively reduce pyrite oxidation and acid formation.

Jan 1, 1982

By Jack White

W. I. Garms-—The authors state that when they added 11 tons of balls to the 45 pct volume ball load, the power needle did not budge. The question arises as to whether any increase in capacity accompanied the 11-ton addition. It is hardly conceivable that all of the balls making up the l l-ton addition were sterile. However, as the work done in the ball mill is not by kilo-watthours per se or balls per se but by kilowatthour-balls, it is possible that the kilowatthourballs in the mill before the ll-ton addition had a different amperage, voltage or robustage than those in the mill after the addition and that the overall outcome was that equal work was done before and after the addition. The authors can keep the efficiency that they got with the 45 pct volume 1-in. ball charge and get additional capacity by putting more kilowatthourballs to work in the form of the addition of 11 tons of 2-in. balls to the present ball charge, and subsequent makeup additions by weight of 20 pct 2-in. balls and 80 pct 1-in. balls. J. F. Myers (authors' reply)-—Mr. Garms points his finger at the 11 tons of "sterile" balls added to the Tri-cone mill. A fact so interesting to us that we felt it should be reported. Clearly, ball slippage at the existing mill speed prevented any further transfer of power from the shell to the ball mass. We agree that the kilowatthourballs would increase, were we charging rough 2-in. balls as suggested by Mr. Garms. The assumption is, of course, that we would get a corresponding increase in work done. Our reported data (CIME meeting, Vancouver, 1946) shows a gain of work accomplished of 7.6 pct as we decreased the ball size from 2 in. to 1% in. and a further gain of work accomplished of 2.1 pct when we went from 1 % in. to 1 in. The small ball results reported by H. R. Banks at Chapman Camp are also very convincing. In the case of 2-in. balls they would take the conventional ball path and start cascading. They would thus destroy the classifying pool over the "foot" of the

Jan 1, 1951