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By Louis Jordan

THIS paper presents in an abbreviated form the chief points of interest in an investigation of the tarnish-resistant qualities of silver alloys, an investigation which has been carried out as a joint research by the Bureau of Mines and the Bureau of Standards and will later be reported in detail in an official publication from these bureaus. In 1923 a Commission of Gold and Silver Inquiry was created by a Resolution of the U. S. Senate to study the causes of the depressed condi¬tion of the gold and silver industry. In cooperation with this commission the Bureau of Mines made a preliminary survey to determine in what ways, if any, it might be possible to increase the uses of silver. One of the possibilities indicated by this survey was the development of silver alloys which should be non-tarnishing, or at least less-tarnishing, than the usual sterling silver (copper-silver). The preparation of a rather wide variety of silver alloys and the determination of their behavior under accelerated tarnish tests in the laboratory was therefore undertaken by the bureaus, of Mines and Standards as a joint investigation. PREVIOUS WORK ON TARNISH RESISTING SILVERS At about the time this work was undertaken interest in tarnish-resisting silvers was rather keen due to announcements from England that there had been developed a new silver alloy, "Silanca," which was resistant to tarnish. It was even frequently described in the popular press as "non-tarnishing." A few samples and several analyses of "Silanca" which were available indicated that it was an alloy of sterling fineness, that is, it contained about 93 per cent. of silver, with approximately 4.5 per cent. of antimony and either cadmium or zinc, or both, to make the remaining 2.5 per cent.

Jan 1, 1927

By W. H. Craigue

THE scope of this article covers only the mathematical principles involved in discounting to present worth future expected profits and it is believed answers definitely two questions, which were raised at a recent meeting of the Committee on Methods of Valuing Coal Properties, as follows: 1. The accumulative effect of carrying charges on the value of coal mines showing definitely the number of years beyond which the coal may not be mined at a profit and subsequent to which the possession of any unmined coal will be a liability rather than an asset. 2. The effect on the valuation of coal mines, in the presence of the carrying charges described in question 1, of an increase in plant capacity and production. In general, in considering these questions, it may be stated that the consideration of an increase in plant capacity and production follows as a matter of course after a determination has been made of the year beyond which no profits are to be realized (giving the carrying. charges accumulative effect, or in other words capitalizing the carrying charges, as shown hereinafter). For example, if it is determined that any coal that is unmined after 45 years will have no value or less than no value, the question immediately arises as to whether or not a plant should be constructed that would result in a yearly production great enough to extract the entire tonnage in a time less than 45 years, and if so the number 'of years less than 45 years that would, from a financial stand-point, be the most desirable, all under the assumption that the market for the product or the transportation facilities are such that the yearly production can be increased to the desired amount.

Jan 1, 1933

By Y. L. Yao

THE NaT1-type compound may be considered as the penetration of two diamond lattices in such a way that a superstructure of the bcc lattice is formed. Examples of the NaT1-type compound of lithium are LiZn, LiCd, LiA1, LiIn, and LiGa. Except for LiZn and LiCd, each molecule of these equiatomic compounds contains a total of four valence electrons. In LiZn and LiCd it was suspected (for example, see Ref. 1) that the fourth electron was withdrawn from the 18-shell of zinc or cadmium. An incomplete 18-shell would have to show strong paramagnetism. In 1955 Klemm and Fricke2 determined the magnetic susceptibility of LiZn, LiCd, LiA1, and LiIn (also NaTl and NaIn). The molar susceptibility of the outer electrons of LiZn and LiCd was found to be not strongly but weakly positive; that of LiAl and LiIn not negative but weakly positive. Thus they questioned the hypothesis about LiZn and LiCd in particular and the description of the NaT1-type structure in general. However, they did not determine the magnetic susceptibility of LiGa. This note is to report results for all five compounds of lithium. The starting materials are 99.9 pct pure lithium sticks containing less than 0.005 pct Na. 99.9 pct Zn, 99.9 pct Cd, 99.99 pct Al, 99.999 pct In, and 99.999 pct Ga. Weighed amounts of two components were wrapped in tantalum foil and placed in a graphite crucible. It was found that the tantalum sheath minimized the vaporization losses of lithium during melting. The sheath was easily stripped from the alloy rod and the tantalum in the alloy was barely detectable (less than 0.01 wt pct). The melting was performed in a resistance furnace under an argon atmosphere. Alloy specimens were annealed for 1 hr at 400°C in vacuum. The magnetic susceptibility at room temperature was determined by the Faraday Method, using the procedures previously described.' The results are shown in Table I. The interpolated values at 50 at. pct of Li and the average values at 48 to 52 at. pct of Li at 20°C determined by Klemm and Fricke2 are also shown. It is seen that the present value for LiZn and LiCd is slightly more positive but the present value for LiAl and LiIn is slightly less positive than their corresponding values. Also, it is noted there is an abrupt decrease of susceptibility of LiAl from 51.2 to 52.5 at. pct of Li. Klemm and Fricke2 found that the total susceptibility of LiZn, LiCd, LiA1, and LiIn is almost independent of temperature. slater4 gave a working expression for the diamagnetism of the atomic core as follows:

Jan 1, 1964

THE RELATION OF THE ENGINEER TO RECONSTRUCTION FIFTY-THIRD MEETING OF BOSTON SECTION The fifty-third meeting of the. Boston Section was held April 28. The speaker of the evening was the new president of the Institute, Mr. Howard V. Winchell, who spoke on "The Relation of the Engineer to Reconstruction." He told of the part engineers had played in the war and paid tribute to Herbert E. Hoover as an example of what engineers can do. He said that engineers are not taking enough interest in politics, although it is badly needed as shown by the evidences of Bolshevism even in America. Conditions have suddenly changed; whereas we formerly borrowed money we are now loaning widely to foreign countries and our investments, abroad have to be protected. A committee is badly needed to investigate and determine the actual conditions. The Government has already been invited to cooperate with the Institute along professional lines and this should lead to closer contact between our Society and the Government. Mr. Winchell then went on to describe some of the mining conditions in Russia. He brought out the point that the rich platinum deposits are exhausted and only the poorer sands remain. The largest copper properties average less than 2 per cent. copper and there are some 4,000,000 tons available in .the Caucasus region near Batum. There are approximately 100,000,000 tons of high-grade manganese ore scattered in small deposits in the eastern Ukraine. There are some copper mines in the East, butt they are almost exhausted. The Baku oil field is the second largest in the world and there is probably oil in Persia. There are also manganese in Siberia and coal veins of enormous thickness.

Jan 7, 1919

IN THE early evening of October 15, 1954, a large specially designed truck, convoyed by a second smaller one, arrived at Silver Bell, Arizona, completing a ten-hour 110-mile journey from Phoenix. The big truck was driven through gaps left in a previously prepared concrete foundation, the load was jacked up, the large girders that constituted the bed of the truck were pulled away, and the load was then lowered into place on the foundation. A crew of two men, the two truck drivers, finished the job in a little more than an hour. When they were through, a complete and attractive three-bedroom house, prefabricated in Phoenix, was almost ready for occupancy. About all that remained to do was to connect the utilities-water, electricity, plumbing, and gas. The kitchen and bathroom equipment and appointments were superior in every respect, and there was a built-in car port for the automobile of the prospective residents. This family domicile was one of more than one hundred, each averaging about $8,000 in cost, that the American Smelting and Refining Company has provided for its employees engaged in mining and milling 7,500 tons per day of low-grade Porphyry copper ore. Aside from the fact that it is more economical-partly because of the variety of union craftsmen needed to build and equip a house-to do the work in a city 110 miles away, the significant point is the high quality of housing that is provided for what may be called in nostalgic vein the "mining camp" of 1955. Silver Bell is typical of all the Porphyries in this respect though the community is relatively small. At San Manuel

Jan 1, 1957

By F. R. Hewitt

THE methods of mining talc are simple, and in western North Carolina are almost entirely by open cut and quarry. The larger part of the talc of this section lies in various-sized "veins" inclosed in quartzitic walls, the majority of which have by folding been thrown into a perpendicular position, or nearly so, and the exposed edges of which have been covered by debris from erosion of the mountain above. This covering of loose rocks and earth is from 5 to 25 ft. thick, and in most cases has to be removed because it is difficult to support. Sometimes the covering is heavy enough to "catch" and timber successfully, and in this case the talc can be worked out by the usual method of following the "vein," using stulls for holding up the walls until the vein is worked out, and then allowing the cut or drift to fall in. In some cases it proves more convenient to sink shafts and run drifts, following the talc "veins" until exhausted. The talc deposits of this section are badly broken and faulted both laterally and perpendicularly, and in some cases are found many feet below the level of drainage, necessitating pumping at considerable expense. . My own experience in mining talc has been that the chief point is to get a reliable "vein," and that then the mining is not as difficult, or any more so at least, than that of any common ore. If the. "veins" are pure talc it is simple; if the talc is admixed with foreign matter, such as tremolite in excess, or stains of iron or manganese, as is often the case, one had better abandon the deposit.

Jan 8, 1916

By Jan D. Miller

Under the name given to this column, I almost feel obliged to write about some aspect of grinding, but I have decided instead to comment on the future of chemical processing. In recent years, I have seen a tremendous interest in extractive metallurgy develop among undergraduate and graduate students at the University of Utah. For example, of the 12 graduating seniors this year, over half seem to prefer extractive metallurgy to physical metallurgy. In particular, they seem to be most interested in hydrometallurgy, or chemical processing, obtaining industrial exposure to the phenomena they study via part-time employment at the Kennecott Research Center and the USBM Metallurgical Center in Salt Lake City. The stimulus has been generated by society itself. Many students are dedicated to the proposition that new technology can circumvent the destruction of our environment, a concept which provides considerable motivation. At the governmental level, the recent concern for the quality of our environment has created action in the area of chemical processing both through imposition of stringent air and water quality standards, and through increased funding for technological research in this area. The National Academy of Sciences (NAS) gave impetus to this movement when it pointed up the need for development and support of such disciplines as extractive metallurgy, particularly chemical processing, in a recent report on Mineral Science and Technology. The recommendations in the NAS report have prompted governmental action on many fronts, including the Bureau of Mines, and have also given rise to direct legislation in the form of two bills -H. R. 3492 and S. 635- presently before Congress to a mineral engineering education. The report recommends that chemical processing technology (more generally extractive metallurgy) be developed by both new engineering techniques and unconventional chemical techniques such as application of the chemistry of nonaqueous liquids to mineral systems.

Jan 1, 1971

By Frank Firmstone

IN 1871, two furnaces at the Glendon Iron Works, which had been blown out on account of the "coal strike," were altered from the open-top plan with side flues for collecting the gas, to closed tops with cup and cone. In one furnace the suppression of the side flues permitted a considerable alteration in the profile, but in the other (No. 5) no change in this respect was made; the side flues were simply bricked up and new ones cut through the sides close to the top. This furnace was in blast over four years, and we can, therefore, form a pretty good idea of the effect of the alterations on the furnace process. The principal dimensions are; Height 72'; greatest diameter, 18'; diameter at tuyeres, 8'; diameter of top, 10'; diameter at stock line (point at which the top of the materials is kept), 11'; cubic contents, 11,900 cubic feet. The table below shows the average results for periods of twenty-six weeks each. 1st, of the open-topped furnace; 2d, of the furnace with the first charger used, which was an ordinary cup and cone (diameter of cone 5' 2") 3d, with the charger used ever since, a "double" cone 7' 5" diameter outside, having a central opening 3' in diameter. The diagram (Plate II) shows the daily variations, in the grade of the irons for the same periods.* * In calculating the average grade of each day's iron, each twelve hours was taken by itself whenever more than two kinds of iron were made in the 24 hours, and the diagram drawn accordingly. By counting, it will be found that there were more such days with the single cone than with the "double" cone, and more with this than with the open top. † Anthracite.

Jan 1, 1876

W. L. Saunders, New York, N. Y. (communication to the Secretary*):—The Laramie tunnel, though a small one, compares very favorably in the speed of driving with the great Alpine tunnels which have the record so far. I think it safe to say that, taking all things into consideration, the record made at Laramie is the best American record, though it still falls short of the long-tunnel records abroad. In discussing tunnel-records it must always be borne in mind that there are conditions peculiar to each individual tunnel job, so that no comparisons are complete, fair and conclusive. At Laramie there is one point which stands out prominently, and which distinguishes this from any of the recently-built Alpine tunnels, and that is that here we have great progress in an American driven tunnel without the use of a carriage for mounting the drills. At the Arlberg and Loetschberg tunnels, the carriage was an essential condition for progress. All the heading-drills were mounted upon a bar which rested upon a small carriage. This carriage was withdrawn after the drilling and run into the heading after the blast without much disturbance of the drills, and with very little adjustment except that required in jacking the horizontal bar across the tunnel. The carriage was so small in its track-area that it required little mucking to run it in to the face; and as the rock-drills used were heavy machines 38 in. in diameter, progress in setting up and drilling was very much accelerated by the use of the carriage. At the Laramie tunnel hammer-drills were used instead of piston-drills, and here we have an important distinction which

Jan 1, 1913

By P. J. Jorgensen, J. H. Westbrook

The anomalous indentation creep of nonmetallic solids is shown to be due to the presence of adsorbed water. Although a specific mechanism is not proposed, it is suggested that the water may be present in two chemically adsorbed states. DEPENDENCE of the indentation hardness of solids on the time of load application was first studied systematically by Hargreaves1 in a study of lead and certain low-melting alloys. This technique has become known as indentation creep and has been exploited particularly by underwood and by Mulhearn and Tabor3 as well as by others.4°7 For metals good correlations have been found between the time dependence of hardness over several orders of magnitude in the seconds range and creep parameters from conventional tests at the same temperature where creep strains were measured over hundreds or thousands of hours. However, Walker and Demer8 and Mitsche and Onitsch9 observed extensive indentation creep at room temperature (particularly for light loads) in certain minerals and in materials such as lithium fluoride and magnesium oxide for which conventional creep is ordinarily not observable unless the testing temperature is at a very much higher fraction of the melting point. Normal behavior was observed' for metals such as copper, i.e., negligible time-dependent flow during room-temperature indentation. Walker and Demer attempted to find some distinctive difference in the surface deformation markings about indentations in the anomalously behaving materials at short and very long indentation times. No significant differences were observed. Increased duration of loading was found, however, to result in an increase in the length of glide of edge-dislocation loops extending into the interior of the crystal. Jorgensen and Westbrook,10 in a recent study of

Jan 1, 1965

By Len Ramp

CHROMITE deposits in southwestern Oregon occur along definite zones or horizons in sill-like ultramafic intrusions. These horizons are here referred to as ore zones and are distinguishable only by relatively Shin and scattered, discontinuous chromite occurrences. The zones are tabular in shape but are usually folded and faulted by the intensive post-intrusion deformation the ultramafic rocks have undergone. A single zone may contain disseminated, nodular, banded, or pods of massive chromite. The typical chromite deposit is composed of a series of thin lens-shaped bodies that lie along a definite plane and generally show evidence of magmatic flow with their long dimensions aligned in the direction of flow. A body of chromite often pinches down to a narrow wisp only a fraction of an inch thick. This thin streak of chromite may point to or be connected with another body of chromite. In some deposits the orebodies have a definite rake. The depth at which chromite may be found can be predicted by its position in a folded intrusive, provided that adequate structural evidence is available. Although the ore shoots are characteristically discontinuous, there is theoretically no limit to the depth at which chromite may be found. Origin: All the chromite deposits examined in southwestern Oregon are of magmatic origin, that is, the chromite was an original constituent of the peridotite magma and became segregated in varying degree from the magma to form the ore de- posits. Examples of early, intermediate, and late magmatic chromite have been recognized in the area. Crystallization of the principal minerals (olivine, pyroxene, and chromite) was apparently near completion at the time of intrusion of the peridotite magma. The magma acted as a viscous crystal mush stringing out aggregates of pyroxene and chromite in the direction of flow. These streaky accumulations are termed schlieren.

Jan 8, 1957

By S. Usui, I. Iwasaki

The adsorption mechanism of dodecylammonium acetate (DAA) on mercury in potassium fluoride solutions at natural, near neutral pH was investigated. Difler-ential capacity combined with electrocapillary measurements on a dropping mercury electrode were found to provide a sensitive and reliable approach. A shift in the electro capillary maximum (or the point-of-zero-charge) towards positive polarization of the surface due to the adsorption of amine indicated a specific affinity of dodecylammonium ion for mercury surfaces. The amine was shown to adsorb competitively with potassium ion on mercury. Through correlation of the adsorption density of the amine, calculated from the thermodynamic analyses of the electrocapillary curves, and of the diflerential capacity curves, the adsorbed state and the orientation of the amine at the interface were considered. The similarities and the differences in the adsorption behavior of the amine on mercury and on such ionic solids as quartz, silver sulfide, and silver iodide were evaluated. With the promise of flotation providing a cheap and large-scale process for the upgrading of low-grade ores and magnetic concentrates, the iron ore industry has made a sustained search over the years for a flotation reagent of general applicability and high selectivity. Having shelves full of commercial reagents already on hand and anticipating more, both the users and the suppliers are in need of an experimental approach sensitive enough to differentiate the individual characteristics in each group of reagents. Therefore, the adsorption behavior of various flotation reagents on mineral surfaces from aqueous solutions has been a subject of much investigation. The current view of adsorption based on the electrical double-layer theory is formulated on the assumption that certain ions in solution act as potential-determining ions. Their concentrations fix the potential drop across the double layer and their adsorptions govern the surface charge.' Two methods used to study the adsorption

Jan 1, 1971

By Frank Firmstone

In April, 1873, No. 2 furnace at the Glendon Iron Works being out of blast, it was decided to alter it from an open to a closed top. The three side flues, through which a part of the gas was formerly taken off, were 15 feet below the top, and as, for various reasons, it was not convenient to cut new flues through the brickwork at the top, as is commonly done with closed-top furnaces, a modification of Coingt's charger was employed. This apparatus, as figured by De Vathaire,* consists of a cup or hopper, like that used with the cup and cone, and a central pipe for taking off the gas, which descends some distance into the furnace, and has a projection around it forming a seat for a ring of a triangular cross-section, which closes the opening between the cup and the central gas-pipe. The charge is put into the cup, and by lowering the ring, is thrown into the furnace, a part going outside of the ring toward the walls, and a part through the inside toward the gas-pipe. In this form the apparatus was not applicable, for: 1st. With a gas-pipe three feet in diameter, in a top eight feet in diameter, the openings left by lowering the ring would not be large enough to let lump coal pass through. 2d. For the charger to shut tight, the ring must bear equally against the projection made for it on the gas-pipe, and against the edge of the cup. This would not be difficult to effect when the apparatus is first put up, but a comparatively small change in the relative position of the parts, such as is almost certain to occur from expansion, would cause the ring to touch the pipe or the cup, whichever happened to be the lower, first, and leave a leak between it (the ring) and the other. In the plan adopted (Figs. 5 and 6, Plate I), the central opening in the ring is closed by the bottom of the gas-pipe, whereby more room is left for the passage of the stock when the charger is open, than if the pipe descended into the furnace; and the pipe, instead of being rigidly supported, rests on the ring, when the charger is closed, and follows it for two or three inches as it opens, until stopped by the counter-balance lever C. When the ring is raised to close the furnace top, it comes in contact first with the bottom edge of the gas-pipe, then both are raised together, until stopped by the ring touching the edge of the cup. In this way a good joint is made at both places.

By J. D. Anthony

The Australian continent possesses significant reserves of a wide range of minerals, including bauxite, coal, copper, diamonds, gold, iron ore, lead, manganese, mineral sands, nickel, phosphate, silver, tin, uranium, and zinc. Australia's identified economic resources of many minerals are very large as indicated in Table 1. A sophisticated and highly experienced mineral industry is now an established feature of the Australian economy and Australia is the world's largest exporter of iron ore, alumina, mineral sands and refined lead and amongst the leading suppliers of many other commodities such as coal, lead and zinc ores/concentrates, nickel, refined zinc, tungsten concentrates and bauxite. The industry exports 70% of its production. This is reflected in the value of Australian mineral exports which have grown from about $200m in 1960/61, comprising 10% of total export receipts, to about $1265m or 29% of export income in 1970/71 to around $7061 representing 37% of Australia's total export income in 1980/81. Details of the more significant minerals are as follows: Japan (42.1%) USA (11.3%) ASEAN (6.3%) UK (5.9%) F.R. Germany (3.8%) Republic of Korea (3.4%) New Zealand (2.6%) Also see Table 2. AUSTRALIA'S MINERAL RESOURCES POLICIES Federal and State Governments' Responsibilities Australia has a federal system of government comprising six States, a self-governing Territory and a Federal Government. Under the Australian federal system the Constitution sets down the powers of the Federal Government. All powers not assigned to the Federal Government in the Australian Constitution reside automatically with the States. Certain of these broad powers result in the Federal Government having a significant influence on resources development. For example, in being responsible for economic management, the Federal Government's fiscal and monetary policies have an important effect on industry as well as on State finances. In particular, the taxation regime employed by the Federal Government is of direct importance to decision-makers in the resources industry. The Federal Government is responsible also under the Constitution for external trade matters; and international trade and commodity matters are increasingly important in Australia's international relationships. Foreign investment is another area where the Federal Government has a role to ensure that national interests are protected. This foreign investment power flows from the Federal Government's control of foreign exchange movements into and out of Australia. However, before enlarging on these and others of the Federal Government's powers and policies, it should be emphasized that the State governments, by virtue of their wide powers to regulate matters within their own boundaries, are more directly involved in the day-to-day administration and regulation of mining operations. For instance, the powers of the State governments include the responsibility-for the granting of exploration rights and mining leases, the approval of mining operations and the levying of royalties and other like charges. Administrative arrangements covering the granting of minerals and petroleum exploration and development titles vary from State to State. Before development rights are granted, State governments consider environment protection and rehabilitation aspects of development proposals. The provision of infrastructure within State borders is a matter primarily of State government responsibility. It is usual practice in Australia for State governments to construct and operate infrastructure services such. as railways, ports and electricity generation and transmission. The States may also provide certain public services such as electricity. and water, port and loading facilities, communications, health and education services which form part of the infrastructure of mining operations. In remote areas the mining companies themselves usually are expected to provide much of this infrastructure. However, the Federal Government is primarily responsible in some fields, such as telecommunications and parts of the railways network. State governments carry out preliminary exploration and geological mapping and some are directly involved in the mining of coal for power generation. The Federal Government's responsibilities in addition to economic management, taxation, international relations, foreign capital and investment, include regulation of exports, environmental matters and matters affecting the Aboriginals of the Northern Territory. FEDERAL GOVERNMENT POLICIES The continued sound development of the minerals and energy resources sector is regarded by the Federal Government as being of very great importance. However, the Government does not seek to participate directly in resource developments. It sees its role rather as that of establishing a sound economic and policy climate in which private companies can identify opportunities, seek out customers and marshall the necessary capital for the development of resource projects.

Jan 1, 1982

By George Bain

METHODS of mining building stone of any sort are planned to pro-duce as few fractures as possible, and present a strong contrast to methods of mining metallic ores, which must be crushed eventually and have fractures produced in as great profusion as possible. Shocks transmitted to a stone invariably make it more porous and more permeable and reduce its effective life, therefore methods of mining building stone involve as FIG. 1. THE SUPREME COURT BUILDING, WASHINGTON, D. C. This building illustrates the fine detail of workmanship, unprotected sharp corners and thin edges, and tall narrow columns characteristic of marble structures. These features require exceedingly coherent stone, and preservation of these features for decades or centuries demands many special quarrying precautions to keep absorption to 0.14 per cent or less, a detail not essential to stone for coarser architectural types. few shocks as possible. This is singularly true for marble because marble structures are intended to have long life, greater delicacy of line, more gracefulness and fineness of sculpture than those made from any other structural material (Fig. 1). So that delicate lines may remain in almost perfect preservation for decades, or even centuries, it is important

Jan 1, 1935

By Roshan B. Bhappu, Ronald J. Roman, Dexter H. Reynolds

The reaction between manganese dioxide and molybdenite in a water- sulfuric acid medium was studied at atmospheric pressure and from 25° to 103°C. Both solids are dissolved to give, as final products in solution, Mo(VI), S(VI), and Mn(II). Stoichiornetric relationshifis are most simply represented by the equation MoSz + YMnO2 + 15H+ - HMoO-4 + 2HSO-4 + 9Mn++ + 6H20 The rate of this reaction was found to be dependent on temperature, manganese sulfate concentration, acid concentration, and, in a complex way, the surface areas of both manganese dioxide and molybdenite. Both the total amount of manganese dioxide and tnolybdenite and the ratio of manganese dioxide to molybdenite played a part in determining the over-all rate of the reaction. The effect of acid concentration on the rate was also dependent on the ratio of manganese dioxide to molybdenite. SEVERAL reports in the literature describe reactions using manganese dioxide in water-sulfuric acid media as an oxidizing agent. Nearly all previous work describes interactions between an ion and manganese dioxide, such as the oxidation of ferrous to ferric iron,' or the interaction between a molecule in solution and manganese dioxide, such as the oxidation of toluene to benzaldehyde.2 Only a few references describe the use of solid manganese dioxide to oxidize another solid in sulfuric acid. One report3 states, "Manganese dioxide in dilute sulfuric acid solutions had no beneficial effect (in leaching copper from chalcopyrite), but in more concentrated acid solutions the rate of solution was about the same as that for permanganate." In 1902 a German patent4 described a process which used manganese dioxide in strong (50°Be') sulfuric acid for oxidizing chromite ores to soluble iron and chromium salts. The process consisted of mixing the sulfuric acid with the finely ground ore and manganese dioxide. The pulp was then heated to about 120°C and an electric current passed through it. The manganese dioxide apparently dissolved in the strong, hot acid solution, oxidized the iron and chromium and itself was reduced to manganese 11! then was oxidized at the anode back to manganese dioxide, and the cycle repeated. An extensive study5 of the kinetics of the oxidation of pyrite with manganese dioxide indicated that in dilute sulfuric acid solutions (about 0.1 N) and at elevated pressures the dissolution of the pyrite was brought about by air oxidation of the iron to ferrous sulfate, followed by manganese dioxide oxidation of the ferrous sulfate to ferric sulfate. The mechanism proposed by the authors involved the oxidation of the iron at the surface of the manganese dioxide. Also! the oxidation of sulfide sulfur to sulfate was credited to the oxygen in the air, not to the manganese dioxide. Since the metallurgical literature is lacking in information concerning the use of one solid to oxidize another solid. the current investigation was under-

Jan 1, 1965

By R. G. Ward, P. L. Sachdev

Using an improved maximum bubble pressure technique, the densities of iron silicates at 1400°C have been measured under nitrogen. At the wiistite composition the density has been measured by bubble-blowing experments with both argon and nitrogen and calculated from the measured volume of a known mass of melt under nitrogen. The densities under nitrogen are significantly different from those measured under argon for melts containing less than 28 wt pct SiO2. THE constitution of liquid slags is not well understood, largely because no single property or parameter can be measured which gives conclusive evi- dence of the types and packing of the ions present. Of the many property measurements which can provide information leading to a picture of the constitution of slags, density gives the most direct evidence and has been studied extensively. The work reported here is part of a program of study of densities in multicomponent melts in which the iron oxide-silica system is the solvent. These melts are important as they are fundamental to basic steelmaking, and they allow the study of basic silicate compositions which have hitherto been largely neglected. As considerable disparity exists

Jan 1, 1965

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period June 10, 1916 to July 10, 1916: Arthur Adams, Miami, Ariz. John M. Lovejoy, New Rochelle, N. Y. J. H. Batcheller, Mattapoisitt, Mass. J. F. Manning, Seoul, Korea. R. S. Bonsib, Low Moor, Va. E. P. Mathewson, Anaconda, Mont. E. L. Booth, New York, N. Y. Edwin W. Mills, Seoul, Korea. C. L. Bryden, Scranton, Pa. Arthur Notman, Bisbee, Ariz. F. Crabtree, Pittsburgh, Pa. L. B. Reifsneider, Daiquiri, Cuba. L. B. Eames, Pueblo, Colo. W. S. Schuyler, Berkeley, Cal. S. J. Gormly, Guayacan, Chile. 0. N. Scott, Toronto, Ont., Canada. Ernest A. Hersam, Berkeley, Cal. Arthur F. Taggart, New Haven, Conn. A. W. Hudson, Douglas, Aria. Warren D. Thompson, Boston, Mass. Chas. W. Johnston, West Norfolk, Va. Thor. Warner, IGngman, Ariz. Rodolphe L. Agassiz has been chosen president of the Calumet & Hecla Mining Co., an office which has been vacant for over a year. Percy E. Barbour, Managing Editor of the Engineering and Mining Journal, resigned his commission as 2d Lieutenant in the Main Coast.

Jan 8, 1916

By William H. Spice

Drilling activities in South Central Texas for the year 1945 continued the steady increase over the past two years, while new fields discovered for the year included four new gas fields and one field extension. In the 30 counties included in this area, which comprises district No. 1, Oil and Gas Division, Railroad Commission of Texas, 141 exploratory wells were completed, compared with 61 drilled in 1944 and 29 drilled in 1943. Of these 141 tests, 55 were field well and 86 were wildcats; 38 were completed as oil wells, S as gas and gas-distillate producers, and 95 were abandoned as dry. Atascosa and McMullen Counties were the most active in the district, accounting for 73 of the wells drilled.

Jan 1, 1946

An appropriation of $4000 was made to the United Engineering Society for the support of the work of the Engineering Council. It was resolved that the proposed amendments to the Constitution, regarding requirements for membership, be sent to the membership without comment thereon by the Board of Directors. Forty-one members, and three associates were elected. The status of two junior members was changed to member. The resignation of one member was accepted. The dues of nineteen members who are engaged in active duty with the Allied armies were remitted. B. B. Thayer was elected a member of the Board of Trustees of the United Engineering Society for a period of three years, to succeed himself. John H. Janeway was elected a member of the Library Board for a period of four years, to succeed himself. George C. Stone was elected a member of the Library Board in place of E. F. Roeber, deceased. E. Gybbon Spilsbury was elected representative of this Institute on the John Fritz Medal Board of Award, to succeed himself. J. Parke Channing was elected a member of the Engineering Council for a period of three years, to succeed himself.

Jan 1, 1918