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By Mrs. V. J. DeCarlo, G. P. Salvo, H. W. Schadler, L. M. Osika

The lattice parameter of the inlerrnetallic compound Nb3Sn has been measured as a function of temperature from 80° to 1290°K. The results are compared with published data on the thermal ex- ThE recent interest in the intermetallic compound, Nb3Sn, as an engineering material for the production of superconducting devices has necessitated that certain engineering data be obtained. Because of the difficulty encountered in producing bulk pansion of niobium and indicate that the compound when made by diffusion of tin into niobium at 1000°C, would be subjected to a tensile strain of about 0.1 pct when cooled to room temperature. material which is single phase, the coefficient of thermal expansion has not been measured by dilata-tional methods. Therefore the lattice parameters of fine-grained samples of Nb3Sn produced on the surface of a niobium sheet by heating in molten tin at 950°C have been obtained as a function of temperature. The results are compared with published data on niobium2 and Nb3Sn3 and with lattice-parameter measurements made on small single crystals of Nb3Sn.

Jan 1, 1964

By F. C. Sturges

FOR some time mining engineers have been interested in the possibility of using small diameter shafts, sunk by core drilling, as aids to ventilation and as emergency escapeways. The possibilities are interesting to contemplate, but new methods involve unknowns, and interest tends to remain passive until these unknowns are solved. Recently we have completed two 36-in. diam. core drilled shafts, and wish to make the data on these available to the industry. Both shafts were drilled for the McLain Fire Brick Co., one at its Buckeye mine and the other at its Colonial mine. Both mines are in the fireclay underlying the Lower Kittanning coal. Both mines have been in operation for a number of years [ ] and have required expensive maintenance work on return airways. It was decided that considerable savings could be effected by short-circuiting the air to the surface through small shafts. It was also realized that these holes, located near the present workings, would be of added value as emergency escapeways. Originally, 48-in. diam. shafts were considered, but actual computations showed 36-in. diam. shafts were more than ample at both mines. The shaft at the Buckeye mine is 240 ft deep, and that at the Colonial mine 258 ft deep. Both holes were started in the lower part of the Conemaugh formation and penetrated Conemaugh and Allegheny strata. The holes were started through the unconsolidated materials overlying bedrock by constructing a concrete collar with a wall thickness of 8 in. Then the shafts were drilled by the shot-core drill method. An annular groove was cut in the rock by the abrading action of chilled steel shot run under the shoe of the core barrel. The drilling was done in stages, the core barrel drilling the groove for a certain distance depending on conditions encountered, and then the cores broken off and taken out in sections. The core barrel had a 36-in. o.d. and the finished diameter of the shaft measured almost 37 in. The major questions that could not be answered until the completion of the first shaft were, (I) how much ground water would be encountered, how would it hinder the drilling, and how difficult would it be to seal off, and, (2) how would the walls of the hole stand up. The holes of course could be cased or lined, but that is considerable added expense in any shaft.

Jan 1, 1947

By R. E. Zimmerman

ALTHOUGH flotation of coal is considered relatively new in the United States by coal-preparation engineers, actually it has been practiced to some extent for the past 30 years, It is practiced much more widely in Europe than in the United States. Commercial plants are operating in nearly all major coal-producing countries of the world. A froth flotation plant has been operating since 1930 at the Champion No, 1 preparation plant of the Pittsburgh Coal Co. Unfortunately the term flotation is widely used in the United States by coal-preparation engineers to designate dense medium processes of coal cleaning. As used here, flotation means those processes for cleaning fine sizes of coal in which the coal is collected in a froth or matte at or near the surface of a pulp. The refuse particles remain in the pulp. Two distinct types of flotation are practiced: froth flotation and agglomeration. FORMS OF FLOTATION The theory of the principles of flotation and of the physicochemical foundations surrounding this process has become a complex and scientific field and coal-preparation engineers contemplating use of flotation processes would do well to study the works of Gaudin, 2, 5 Taggart, 3 Zimmerman, 4 Wark, 6 Ralston, 7 Petersen. 8 Bulk Oil Flotation.-In this process the separation of mineral from gangue is accomplished by virtue of the fact that minerals of metallic lustre, as sulphides, or hydrocarbons, as coal and graphite, are wetted preferentially by oil in the presence of water and consequently pass into the interface between oil and water; while gangue or rock is wetted by water and remains in the medium. Beginning in 1860 with Haynes and later between 1897 and 1907, at least 25 patents were granted for bulk oil flotation. Large quantities of oil are required, generally 3 to 25 per cent by weight of feed, and recovery of such oil is a major problem. The Elmore process 3 (1901 and 1902) is an example of a bulk oil process, The Trent process (1902-25) has been used for the cleaning of coal on a commercial scale, According to E. W, Davidson 9 there were five such plants operating in the United States by 1925. They have since been abandoned.

Jan 1, 1950

By C. B. E. Douglas

The following analysis was stimulated by a previous article on evaluation of the water problem at Eureka, Nev., which describes a method using formulas especially devised to calculate flow potential of extensive aquifers characterized by relatively even porosity and permeability throughout. The present discussion submits that the method was unsuitable for solving the kind of problem occurring at Eureka, where the amount of water available, rather than the flow potential, may have been the vital factor. IN an interesting article on evaluation of the water problem at Eureka, Nev.,1 W. T. Stuart describes how a difficult water problem, or one phase of it, may be evaluated by means of a small scale test. Test data are plotted by a method rendering, under certain conditions, a straight-line graph that can be projected to show how much the water table will be lowered by pumping at any specified rate for a given time. A formula is then used to determine the size of opening, or extent of workings, necessary to provide sufficient inflow to enable pumping to be maintained at that rate. At first glance this might seem the answer to a miner's prayer, but a word of caution is in order. It may not be the whole answer. Moreover, results obtained by the method described are reliable only for conditions approximating those assumed. Even where conditions do not meet this requirement, however, it may be possible to draw helpful inferences from the results, perhaps enough to facilitate another approach to evaluation of a problem. The two formulas Mr. Stuart used, the Theis formula and the one developed from it by Cooper and Jacob, were given field checks a number of years ago in valley alluvials by the Water Supply Div. of the U. S. Geological Survey and found to be reliable when the aquifer is very large in horizontal extent and sufficiently isotropic for the test well and observation wells to be in material of the same average permeability as the saturated part of the aquifer as a whole." Extensive valley alluvials, sands, and gravels can be evaluated in this way, and there are even cases in which the method could apply to porous limestones, such as flat beds of very large areal extent that have been submerged below the water table after extensive weathering. These are sometimes prolific sources of water for towns and industries. It is necessary for them to have been above the water table for some geologically long period of time in a fairly humid climate before submergence because the necessary high porosity and permeability, and large reservoir capacity, are the result of weathering, that is, of solution by the carbonic acid (H,CO3) in rainwater formed by the absorption of CO, from the air by raindrops, and this dissolving action must cease when all the H2CO3 has been consumed by re- action with the carbonate to form the more soluble bicarbonate. Consequently this weathering process is largely restricted to a zone that does not extend much below the water level, and submergence is necessary after the weathering to provide large reservoir capacity and good hydraulic continuity. On the other hand, water courses tend to form along faults and fractures in limestone, and to become enlarged by solution, well below water level when, as often happens, fresh meteoric water is circulated rapidly through them to considerable depth by hydrostatic pressure, as through an inverted syphon. Although the reservoir capacity of such water courses is relatively small they may extend far enough to tap more prolific sources. Cavities, and sometimes caves of considerable size, are found in limestones where the acid formed by the oxidation of sulphides has attacked them. This action can take place as deep below water level as surface water is carried by syphonic or artesian circulation, because the oxygen it carries in solution will not be consumed until it reacts with some reducing agent, such as a sulphide. Moreover, the formation of acid and solution of limestone in this way is not confined to the immediate vicinity of the sulphide. Oxidation of pyrite, for example, results in formation of acid in several successive stages, each taking place as more oxygen becomes available, as by the accession of fresh water into the circulation at some place beyond the sulphides. When the acid thus formed attacks the limestone, CO, is liberated and the ultimate effect of the complete oxidation of one unit of pyrite will be the removal of six times its volume of limestone as the sulphate and bicarbonate, both of which are relatively soluble. The reaction may be continued or renewed along a water course far from the site of the sulphides, where the small electric potential produced by contact with the limestone helped to start the reaction. Mr. Stuart refers2 0 caves in the old mining area in the block of Eldorado limestone southwest of the Ruby Hill fault at Eureka, Nev., and to the cavities encountered in drillholes in the downthrown block on the other side of the fault. Although he interprets these cavities as evidence that this formation was sufficiently isotropic (evenly porous and permeable) to give reliable results by the method he describes, they may, in fact, be entirely local conditions. There is reason to think they were probably formed

Jan 1, 1956

By G. P. Hulst

THE Parkes process lead refinery of the International Lead Refining Co., at East Chicago, was built by the International Smelting & Refining Co. to treat the lead bullion produced by its Tooele plant, at Tooele, Utah. The plant was designed and constructed under the direction of the writer. Ground was broken Apr. 16, 1912, and exactly six months later the plant was in operation and lead was being cast. The capacity of the plant, running 25 days per month, is 5,000 tons. The four products of the plant are common lead, corroding lead, antimonial lead, and Doré bullion. The site is an area, 64 acres in extent, lying north of 151st Street, between McCook Avenue and the Canal. The Indiana Harbor Belt Railroad, Baltimore & Ohio Chicago Terminal, and Pennsylvania Railroad enter, the yard at the plant. There are five, storage tracks and space for storing 100 cars in the yard. The main lead to the storage tracks passes over a 100-ton track scale on entering the yard...

Jan 8, 1914

By E. B. Burwell, R. H. Nesbitt

Designed by army engineers, the NX borehole camera provides the most economical method of subsurface exploration so far devised. Continuous cylindrical color photographs now reveal minor flaws in foundation bedrock not always disclosed by borehole samples. A unique projector transforms the photographs into true-to-scale images of three dimensions. ANEW milestone in the progress of photography and subsurface exploration was reached when the Chief of Army Engineers announced the development of the NX borehole camera. In obtaining continuous undistorted cylindrical color pictures of dry or water-filled borings the device surpasses all other cameras designed for photographing interior surfaces of pipes, wells, and conduits. The usefulness of the camera and the unique projector that comes with it are at once apparent. To the geological, mining, and civil engineer alike it signifies the end of guesswork with respect to underground conditions that have eluded identification by conventional core-drilling methods. To the medical profession it may well signal new progress in photo optics which could result in cylindrical color photographs supplementing the X-ray and existing photographic methods used in exploratory surgery. The pilot model of the camera has more than paid for itself as a result of its success in bringing to the surface at two dams information previously obtainable only by costly drilling of mansized boreholes for subsurface on-the-spot examination. Such bores cost as much as $200 per lineal foot as against $10 per ft for the conventional 3-in. or NX exploratory core borings from which the present invention derives its name. The NX camera can now photograph completely the interior surface of these borings. Research and development for the first camera and projection equipment were conducted by Engineering Research Associates, Division of Remington Rand, Inc., under the technical supervision of the Geology and Geophysics Branch, Office of the Chief of Army Engineers in Washington, in accordance with plans and specifications furnished by this branch. Subsequent modifications of the camera-lowering device, transporting equipment, and special field tools were made in the Corps of Engineers' Ohio River Division Laboratories in Cincinnati. The background of this development is interesting. Among the more difficult foundation problems involved in construction of concrete dams are those resulting from bedrock imperfections that escape disclosure by conventional exploration methods. Often these imperfections are of sufficient magnitude to introduce costly changes, especially when their presence is discovered only after foundation excavation is well in progress. Bedrock flaws most frequently camouflaged may be ruptures resulting from the enormous stresses to which rocks have been subjected, or they may be planes or zones of weakness related to chemical alteration and underground erosion. Obviously, detailed information on their location, dimensions, and structure is important, as these factors can affect the stability of a dam and the security of life and property downstream. Their discovery and appraisal entail extensive subsurface exploration. At present the most economical exploratory tool available to geologists and engineers is the small-diameter diamond core drill by means of which cores of the foundation bedrock are recovered for examination and testing. All too often, however, these samples fail to disclose minor foundation flaws that may be of major importance before a structure is completed. As a result, the small-diameter drillings are supplemented generally by more reliable but much more costly shafts, tunnels, or large-diameter calyx drill holes that permit the investigator to examine the foundation rocks in place. It was to reduce the number and cost of these expensive and time-consuming investigations, as well as to obtain more complete information on rock structure from the smaller borings, that the NX borehole camera was developed. That it has been eminently satisfactory in accomplishing that purpose is demonstrated by its success most recently at the Folsom dam, under construction on the American River, 23

Jan 1, 1955

By Charles Willis

THE time is no longer when a man can act as an independent unit; the appreciation of the interdependence of one man upon another has emphasized the importance of the social unit. Epidemics have made us recognize that even a man's health is not distinctly his own to control as he pleases. The physical examination of workmen previous to employment started with an effort to prevent the spread of tuberculosis, for tuberculosis may be .detected in its early stages and cured. But it was soon found that many other diseases were detected and the saving of lives made possible. The physical examination does not mean the elimination of the unfit-on that basis it would utterly fail- but rather the measuring of a man's physical fitness and placing the man where he can do the best for himself, his fellow worker, and the company. Industry as a whole cannot expect to live up to the standard of physical examination set for the army, nor should it expect to do so, for in all branches of industry there are types of work that do not require -the same amount of endurance as does army work, and the placing of men with physical limitations in the work for which they are' capable permits a higher average of physical fitness for the work requiring physical excellence.

Jan 7, 1919

By Henry W. Turner

The following notes were taken on a trip through northern Korea in the fall of 1910. We started with about 19 Korean ponies, and as many Koreans, from Shin Anju, on the railway from Seoul to Antung. We passed through the ancient walled city of Anju, and thence up the valley of the Anju river. We then crossed over to the north into the Kalsan drainage, thence over another divide to the Chasung river, and finally reached the old Korean copper-smelting camp of Tong Jom— in all a distance by trail of about 200 miles. The return trip was made with ponies to Mampochin on the Yalu river, and thence' down the river in a junk to Antung. The route of travel is shown on the sketch map, Fig. 1.

Jan 1, 1913

Aaby, Alton O , (S'47) Univ of Minnesota, Mimeapolis, Minn Aaby, Waldo S , (S?48) Univ of Minnesota, Minneapolis Minn Aalde, Kaare, (S'48) Univ of Nevada, Reno, Nev Aaring, Floyd D , (S'48) Univ of Oklahoma, Nor man, Oka Aaronson, Hubert I , (S'47) Carnegie Inst of Technology, Pittsburgh, Pa Abbott, Peyton Osborn, (S'46) 1502 Westover, Austin 21, Texas Abel, Malcolm D , (S'47) Univ of Texas, Austin, Texas Aberg, Richard S , (S'47) Univ of Minnesota, Minneipolis, Minn Abrahamson, Guy C , (S'43) 420 W Dennis St , Wilmington, Calif Abrahao, Benjamin, (S'46) Escola Politeenica da Unnersidade, de Sin Piulo, Braizil Achter, Meyer R , (S'46) Carnegie Inst of Tech , Pittsburgh, Pa

Jan 1, 1952

By C. E. Berry

NATURAL stone or manufactured porcelain pebbles are used as the grinding elements in pebble mills and the mills are lined with stone or porcelain blocks. Steel balls usually form the grinding medium in ball mills, and the mills may he lined with steel. Pebble mills are used to avoid contamination by metal of the material being ground, to avoid rapid wear due to corrosion, and for other specialized reasons. Belgian silex (silica) blocks formerly were used widely for lining pebble mills, because of their good resistance to wear, light color, and low cost, but the importation of these blocks was suspended early in the war. The stocks of Belgian silex diminished so rapidly that it was found desirable to compare the properties of a number of domestic substitutes for use in critical operations. Accordingly, a study was made to determine the best substitutes for fine grinding of white pigment and for certain heavy-chemical process work such as the disintegration of phosphate rock in weak phosphoric acid solution. A comprehensive survey of substitute lining materials was not contemplated. It was stipulated at the beginning of the investigation that only materials on the market, available in large quantities, would be tested and that these should be reasonable substitutes from a wear-resistance viewpoint as determined from known physical characteristics. Marble and limestone, for example, could be eliminated immediately. Quartzite, granite and porcelain were selected as likely substitutes for Belgian silex and were subjected to quality tests. MATERIALS TESTED I. Belgian Silex.-Sample blocks of a standard grade were taken from crates in which they had been imported. The stone was light gray in color and contained inclusions of small clusters of quartz crystals as well as light colored portions that might be calcite. This was a siliceous rock which appeared to be of igneous origin. 2. Quartzite.-Samples of quartzite were obtained from a quarry in Minnesota. The blocks exhibited a crystalline fracture. The stone was pink in color and composed of fine quartz crystals bound together with a siliceous cement. 3. Granite A was a fine-grained granite quarried in South Carolina. 4. Granite B was coarse-grained granite quarried in South Carolina. 5. Granite C was a coarse-grained granite quarried in North Carolina. 6. Porcelain A.-Sample blocks of the pebble-mill lining material were obtained direct from the manufacturer. It was white in color and of lower specific gravity than the natural materials. It did not have a crystalline structure. 7. Porcelain B.-Sample pebble-mill lining blocks of the porcelain were received direct from the manufacturer. It was white

Jan 1, 1946

By E. S. Wheeler

The conversion plant of the Clirnax Molybdenum Co. is at Langeloth, Washington . County, Pennsylvania, approximately 30 miles west of Pittsburgh. The molybdenite concentrates converted originate in the company's mine and mill at Climax, Co1orado.l They are delivered to the Langeloth plant by rail packed in 175-lb. bags. War production of concentrates at the mill started in 1918 but it was not until about 1920 that any peacetime uses of the metal began to develop. Early conversion of Climax concentrates was mainly into ferromolybden um, produced for the company by a custom smelter. Chronology of Plant Development In 1924 a small hand-rabbled roaster was built at Langeloth, the roasted concentrates being used principally in the production of calcium molybdate by a conventional wet method. The size of the original plant is indicated by the fact that during 1925 about 400,000 lb. of molybdenum was converted. In 1925-1926, a multiple-hearth roaster was erected (12-ft. 0.d. 8-hearth Nichols-Herreshoff); also the first experimental ferromolybdenum was produced at Langeloth. At this time sa.1cium molybdate was produced in the furnace by a process to be described. With continued interest in and increased use of molybdenum, it was necessary to arrange for enlargement of plant facilities. Although only one 12-hearth 16-ft. 0.d. roaster was erected at this time (1929), plans were prepared for a duplicate unit, which was completed in 193 5, giving a potential roasting capacity of some 16,000 lb. Mo per day under the then prevailing roasting practice. Shortly after this second unit had gone into production, increased demand overtaxed the plant, and as a result two 12-hearth 18-ft. 0.d. roasters were placed in operation in 1936 and 1937. This gave the plant a potential roasting capacity of 40,000 to 50,000 lb. Mo per day, and necessitated major changes in auxiliary handling equipment as well as improved facilities for producing ferromolybdenum. Following the introduction (1938) of a new product—molybdic oxide briquets— and because of the constantly growing demand for molybdenum, plant facilities were again enlarged in 1940 and 1941 by the erection of two 16-hearth 18-ft. 0.d. roasters. These two new units, along with a change in roasting practice, brought the potential roasting capacity to 150,ooo to 190,000 Ib. Mo per day, based on about 15 lb. per sq. ft. of hearth area. Other departments of the plant have necessarily grown, until today the plant is modern throughout and completely mechanized, with equipment geared to produce marketable products as follows:

Jan 1, 1944

By Charles H. Jacoby

In 1774 a Swedish chemist, C. W. Schule, first recognized manganese as an element. That same year Schule's associate, J. G. Gahn, isolated the element manganese for the first time. In 1856 the Bessemer process of steelmaking gave birth to the economic importance of manganese. Later, in 1882, Robert Hadfield discovered high manganese steels. Although the primary use of manganese is in the ferroalloy industry, two additional important uses for manganese are making chemicals and dry cell batteries. Manganese is also vital to plant and animal life. Various chemical compounds of manganese are used in fertilizers, feeds, glass manufacture, paints, varnishes, and for numerous medicinal and chemical purposes. For the study of industrial minerals and rocks, only the chemical and battery grade material is of concern, but for the sake of comparison, metallurgical aspects are included in this presentation. Although currently the world's largest consumer of manganese, the United States is producing only minor amounts of ore at the present time. This is due primarily to the fact that although huge deposits of manganese occur within our borders, all are of such low grade as to be economically unfeasible to mine. For many years various government agencies and segments of private industry have devoted sizable sums of money and time in an attempt to upgrade ores from the various deposits, and also in an attempt to recover manganese from blast furnace slags. In view of current world prices, and the quantity of high grade material available, there is little likelihood that any of these approaches will be found to be economically feasible in the near future. Geology and Mineralogy Mineralogy There are over one hundred minerals that contain manganese. These minerals vary from those with compositions that are predominantly manganese to those having only minor percentages. [ ] Geology From a geological standpoint most manga¬nese deposits are complex. In general, it can be said that all primary deposits of manganese are carbonates or silicates. The most productive and profitable have been those of sedimentary origin and residual concentrations. Examples of these residual types of deposits are associated with the metamorphosed lodes of Madhya, Pradesh, India, and the lateritic deposits of Orissa and Bihar, India; nodules in the residual clays of the Philippine Islands, U.S. southern Appalachians and Arkansas, Ghana, and Brazil. Sedimentary manganese deposits are best exemplified by the Nikopol district of Russia and the Tchiatouri area of Georgia, USSR. Hydrothermal replacements are characterized by the rhodochrosite deposits of Butte and Phillipsburg, Mont. In general, the hydrothermal type deposit has not resulted in any large tonnages being produced, but may have given

Jan 1, 1975

H. 0. Hofman, Boston, Mass. (communication to the Secretary*) :—The experimental demonstration by Professor H. Ries, of the fact that a mixture of clay and finely-ground flux will melt more readily than one in which the flux is less fine and therefore less intimately mixed, is very striking, and will be appreciated especially by those who have to discuss, before classes of students, fusions on a small or a large scale. The statement, that I " rather disputed" the influence of size of flux-particles on the ease with which fire-clay mixtures fused, is an erroneous inference from the paper written by Mr. B. Stoughton and myself in 1898.' We did not undertake to study the influence upon fusibility of the sizes of the particles, either of clay or flux. What we did try to find out was, whether the common practice of finely grinding raw or burnt clay, or a mixture of the two, before testing with Seger cones for resistance to heat and to fluxes, xould give the same results as if the materials were tested just as they were going to be

Jan 1, 1904

By J. O. Mack, J. B. Russell

IN recent years, solders containing 20 per cent tin with no bismuth or cadmium have been developed by a few companies, and personnel have been properly instructed in their use. In addition, since the tin shortage, a number of solders containing less than 10 per cent Sn, and some with no tin, are being used in special applications; however, a solder of this type has yet to be developed that is satisfactory for general use. [ ] The purpose of this investigation was to develop an alloy containing a maximum of 15 per cent tin, with no cadmium or bismuth, having solder properties equivalent to or better than those of substitute solders now specified containing i8 to 20 per cent tin (Table I), or even approaching the properties of the standard 40 to 60 tin-lead solder. The wartime restriction of bismuth and cadmium, elements that have beneficial effects on fluidity, solidification range and strength, makes it increasingly difficult to develop a general-purpose solder containing a maximum of 15 per cent tin. In the course of this investigation, 11 elements were used in various combinations with the basic 15-85 tin-lead alloy. These elements were antimony, silver, copper, indium, thallium, lithium, calcium, barium, potassium, sodium and arsenic. In all, 116 low-tin solders were investigated, with the idea of developing a solder that will give satisfactory working properties, specifically in regard to "wetting" of copper, brass and iron, solidification range, capillarity and shear strength of a soldered joint. The relative importance of these various properties plays an important role in the search for substitute solders, since it is almost impossible to retain all of the desired qualities of a high-tin solder and still make drastic changes in the alloy composition. Because of the expected uses of a general-purpose solder, it is necessary that it have properties, especially in regard to wettability, that will enable it to be used on the metals in common use. BASIC CONSIDERATIONS The maximum liquidus temperature of a solder is determined by the particular application involved and the temperature that can be obtained by the source of heat.

Jan 1, 1944

By F. E. Turton

THE town of Rancagua, at the junction of the state and Braden Copper Co. railroads, is located 82 km south of Santiago, the capital of Chile. From Rancagua 70 km to the east, situated in the Andes at an elevation of 7000 ft, is the town of Sewell, the location of a millsite. Two and one half km east of Sewell by underground railroad at an elevation of 7500 to 10,000 ft is the Teniente orbody. The history of El Teniente dates from the eighteenth century, when according to legend a Spanish lieutenant, or teniente, a fugitive from justice, escaped to the Andes and camped at what afterwards became known as the Mineral El Teniente. This man reputedly discovered a vein of high grade copper ore. The first official records date from 1819, when some exploitation was begun, and continue until 1870. The orebody was large and of relatively low grade and was beyond the capabilities of the small groups attempting to operate it. No effort was made to erect a concentrator until William Braden became interested in the property. In 1901 Mr. Braden promoted the necessary capital for the first practical exploitation of the orebody. Barton Sewell and E. W. Nash, both of the

Jan 1, 1952

GEORGE F. KUNZ, New York, N. Y. (written discussion*).-We have been informed that the nickeliferous ores of Sudbury could furnish more palladium than the whole of the present world supply, together with a large amount of platinum. As the quantity of ore melted in Sudbury in 1916 totaled 1,521,689 tons, giving 80,010 tons of matte, and as the average of 3 years, up to 1915, are stated to show an average of 0.10 oz. of platinum and 0.15 oz. of palladium per ton of matte, this would indicate the presence of 12,000 oz. of palladium and 8000 oz. of platinum in the ore mined in 1916.1 Interest in the platinum situation is now more intense than it has ever been, and the great importance of this metal for many special uses is being increasingly appreciated. For munition manufacture, for chemical apparatus, in dentistry, and for jewelry, it has been and continues to be in great demand in spite of the phenomenal rise in its value. It is true that this has necessarily led to a search for substitutes, especially for dentistry and chemical uses, but while some of these have been found to answer the needs fairly well, for many 'other purposes platinum is still employed in spite of its great cost. As to the jewelry industry, the most public-spirited efforts have been made to restrict its use, and its employment in the manufacture of watchcases, purses, bracelets, and catches has been abandoned, gold being used in its place. The prime cause of the present shortage is, of course, the elimination of 'the Russian supply which, in normal times, constituted probably more than 90 per cent. of the world's production. This makes an intensive

Jan 4, 1918

By R. M. Briney

A RETURN to nonwar conditions characterized the year 1946. The acquisition and forced use, under Government auspices, of low-grade and uneconomic ores, both foreign and domestic, ceased in 1945, but there was some carry-over into the early months of 1946. The world shipping situation delayed the procurement of some foreign ores, but conditions were improving by the end of the year. No actual shortage of any important alloy was experienced, hence the industry was able to make prompt shipment of orders placed. Price levels of ferroalloys, which had remained virtually constant through the war years, were forced upward, with increases on specific products as conditions necessitated. Standard ferroman-ganese and low-carbon ferrochrome were notable exceptions in that their price did not change. No new ferroalloy smelting plants were constructed. The Defense Plant Corp.. sold the works at Ashtabula, Ohio, to the Electro Metallurgical Co. A new type of ferroalloy furnace was described at the Birmingham meeting of the Electrochemical Society. Known as the "Elkem Rotary Furnace" it is distinguished by a rotating shell. The whole furnace, including shell, refrac-

Jan 1, 1947

By F. E. Griffith

Several disastrous and a great number of near-disastrous mine fires have been started by igniting the combustible conductor insulation and outer covering of trailing cables. Those who have had experience in fighting such fires know that they are extremely difficult to combat and extinguish owing to the irritating and noxious gases, fumes and vapors evolved from evaporation, distillation and combustion of the sundry compounds used in the construction of cables. When electric-motor-driven coal-cutting machines were first introduced in coal mines, the electricity was transmitted to the apparatus by two single-conductor trailing cables. Later, two-conductor parallel and concentric types were developed. These early cables were made with the materials available at that time with relatively little thought given to using new materials or utilizing the old to the best advantage. The copper conductors were stranded to give flexibility, but there were too few strands and the method of laying them was such that they did not endure well the stresses of twisting and pulling, to which trailing cables used in mines are usually subjected. The rubber insulating compounds used were not satisfactory in resisting water, high temperature, and the crushing stresses encountered in mine service. The outer coverings were cotton or jute braids saturated with tars or asphalts having relatively no abrasive resistance. In fact, the only consideration given to trailing cable design because of its extremely short life, was to construct it at the lowest possible cost. With increased electrification and mechanization, more serious problems were encountered. Cables used in mines were exposed to more severe conditions than in any other industry. The excessive overload currents, poor heat dissipation, severe abrasion, crushing loads from falling material, runovers, and any of the other things that tend to destroy cable, called for vast improvement in trailing cable design for mine use. About 1918, one manufacturer who recognized the need for improving the toughness of cables in order to obtain greater safety and longer life, developed a special rope-stranded conductor, a superior rubber insulation compound and a tough rubber sheath or jacket compound. As a result of this type of construction, broken conductor strands were practically eliminated, the insulating material withstood high temperature without undue disintegration, and the jacket, similar to that used for automobile tire tread, had high abrasion resistance, high tear resistance, and was waterproof. While the initial cost of these cables was higher than the jute-filled braided types, this disadvantage was more than offset by increased safety and longer service. Cables with these improved characteristics were first installed in mines in 1920. Since 1930, the use of braided trailing cables in coal mines has been almost completely supplanted by the more superior types, employing high-grade rubber compounds for insulation and sheath. The next steps taken to improve the

Jan 1, 1949

By H. R. Stahl

THE disseminated lead district of Southeast Missouri lies 70 miles south of St. Louis. The only metal of economic importance in the ore is lead, but minor amounts occur of iron, zinc, copper, cobalt, nickel, silver and cadmium. These minor metals, as might be expected, tend to concentrate in both the flotation and table middlings. In the past, some zinc has been recovered by differential flotation. The silver and cadmium tend to associate with the zinc, and some recovery is made of these two metals at the smelter. The lead occurs as galena, or lead sulphide. The minor metals are also present as sulphides. The presence of oxidized lead is suspected, but has not been definitely proved. The gangue is chiefly dolomitic limestone, with small amounts of sandstone and shaly glauconitic and chloritic minerals. The ore contains about 3.25 per cent lead, occurring as galena disseminated through the gangue. Some of the galena is very finely disseminated, and the mineral in the gravity tailings, or chat, is seldom or never in the free state. The method of treatment of the ore has been evolved over a period of 75 years; hence probably is not far from correct. The milling processes have tended toward simplification during the past 15 years, but recoveries have never been sacrificed for the sake of simplicity. In many cases, simplification of flowsheets has led to better recoveries and operating economies. A simplified flowsheet is shown in Fig. I. The St. Joseph Lead Co. operates four mills in the Flat River district, with a normal total capacity of about 21,000 tons per day, divided as follows: Federal mill, 11,000 tons; Leadwood mill, 4500 tons; Desloge mill, 3400 tons and Bonne Terre mill 2400 tons. The methods of concentration used at these plants are similar in principle; they differ mainly in details and in the type and size of the equipment used. The process of concentration may be divided into five main steps; i.e., dry crushing, wet grinding, classification with its attendant desliming, tabling and flotation. A brief description of these processes will be given, noting important differences in the various plants, and also noting the more important changes or developments of the past few years. DRY CRUSHING The run-of-mine ore is hoisted in skips, the capacity of these skips ranging from 2 ¾ tons to 8 ¼ tons. At the Desloge plant, the ore is hoisted in 2-ton mine cars on self-dumping cages. All ore is hoisted at shafts adjacent to the various crushing plants, no ore being transported on the surface. Primary breaking at all the mills is accomplished with 9E Telsmith breakers. Preliminary screening is provided ahead of most of these crushers, either by station-

Jan 1, 1943

MARSHAL Foch has been made an honorary member of the four national American societies of civil, mining and metallurgical, mechanical, and electrical engineers. The governing bodies of these societies, aggregating 45,000 members, conferred this signal honor in expression of the appreciation of American engineers for the unmatched services of this master of engineering principles. At Engineering Societies Building, in New York City, on Tuesday afternoon, Dec. 13, the presidents of the four societies presented one beautifully engrossed certificate of honorary membership in the four societies. The auditorium was filled so that not even standing room was left, more than a half hour before the cere-monies began, and the main entrance on the street had to be closed. J. Vipond Davies, president of the United Engineering Society, made the opening address. Col. William Barclay-Parsons, 'who was commander of the first engineer regiment to go abroad, addressed Marshal Foch in French. Colonel Parsons said: The art of engineering was defined a long time ago as "the art of directing the great sources of power in nature for the use and convenience of man." No better definition can be found today. Of all the sources of power in nature, the greatest, the most valuable, and at the same time the most difficult to direct, is the energy of man himself. He who can direct human energy and turn it to the service of mankind is a great engineer. You, Marshal, have directed a greater mass of human energy than any other man has ever done. And you have successfully directed this mass for the highest uses of mankind, in that you by its aid have preserved for him one of the most precious of human possessions-liberty-liberty not only for your own illustrious country, but for all the nations of the world. The four national engineering societies, of the United States now desire to make record of their appreciation of this fact and to convey to you an expression of their most profound admiration for the great leader of men by conferring on you honorary member-ship in all the societies, the highest honor in their gift and one hitherto never conferred on a single individual. Four thousand members of these societies were enrolled in the armed service of the United States, the greater part of whom had the glorious distinction to serve the common cause in France under your orders. They heard the voice and they saw the hand of the master as he led them through battle to victory. Now we desire that you will still continue to lead us, but in peace, by permitting us to inscribe your name at the head of our roll of honor, where it will be, as your deeds have been, an example to us to do better work, and where it will remain forever a noble inspiration for all future generations. Marshal, in the name of those members of the societies who served under your orders and particularly .in the name of those who fell on the field of honor in France, I salute you.

Jan 1, 1922