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By N. S. Keith

(Read at the Wilkes-Barre Meeting, May, 1877.) THIS question is suggested by a statement made by Dr. Siemens, widely printed in the journals of the day, that a continuous rod of copper, thirty miles in length and three inches in diameter, is capable of conveying that distance, electrically, energy equal to 1000 horse-power. It is not attempted to advance the statement that the source of power shall be zinc, nor even coal, but waterfalls, which from their situation are not practically available for manufacturing establishments in their immediate vicinity. In order to fully consider this subject., we must understand the doctrine, I may say the science, of the correlation of the forces, so called. We must understand that all matter is endowed with an amount of force, and that each atom and molecule, simple and compound, has its specific portion of the whole. This force, at rest, is called latent heat, intrinsic energy, or potential. In motion it is called heat, light, electricity, chemical affinity, attraction, magnetism, power, etc., according to its sensible manifestations. These are the effects of the one force active in different substances, or in different assemblages of matter. Force put in motion comes to rest by reason of the resistance to motion which it encounters; in overcoming

Jan 1, 1878

By N. S. Keith

This question is suggested by a statement made by Dr. Siemens, widely printed in the journals of the day, that a continuous rod of copper, thirty miles in length and three inches in diameter, is capable of conveying that distance, electrically, energy equal to 1000 horse-power. It is not attempted to advance the statement that the source of power shall be zinc, nor even coal, but waterfalls, which from their situation are not practically available for manufacturing establishments in their immediate vicinity. In order to fully consider this subject,, we must understand the doctrine, I may say the science, of the correlation of the forces, so called. We must understand that all matter is endowed with an amount of force, and that each atom and molecule, simple and compound, has its specific portion of the whole. This force, at rest, is called latent heat, intrinsic energy, or potential. In motion it is called heat, light, electricity, chemical affinity, attraction, magnetism, power, etc., according to its sensible manifestations. These are the effects of the one force active in different substances, or in different assemblages of matter. Force put in motion comes to rest by reason of the resistance to motion which it eucounters; in overcoming

Jan 1, 1879

By R. F. Frantz, T. P. McNulty

The upper-level mineralization of the din Buttes, Arizona copper orebody consists primarily of dilute copper silicate impregnation in fault clay and throughout the altered limestone hostrock. Cuprite and native copper are minor with true chrysocolla rare. Owing to the high calcium carbonate and to the hydrogen ion exchange capacity of the clays, acid leaching would be economical only with cheap acid available. Leaching of the silicate copper with reagents other than sulfuric acid is slow and incomplete unless the ore is first heated to disorder the mineralized grains and to reduce partially the contained copper. Following heat treatment, 70 to 90 percent of the nonsulfide copper can be dissolved in aqueous anrmonium carbonate. Recovery of a pregnant solution by counter-current decantation is effective provided ammonium carbonate solution is added to the washing stages in order to oppose adsorption of dissolved copper by clays in the residue. Thermal stripping of the pregnant solution permits recovery of ammonia and carbon dioxide while precipitating copper either as oxide or carbonate. The research program was carried from batch tests through continuous miniplant operation to a five-month campaign in a 20 TPD continuous pilot plant. Pilot plant results, the relationships among key varibles, and a detailed flowsheet are given.

Jan 1, 1973

By T. S. Fuller

The tensile properties of steels at elevated temperatures have been studied by numerous investigatorsll primarily for the purpose of determining their suitability for structural uses. Tests with this objective have been confined largely to the temperature range of approximately 20" to 500' C., because of the rapidly decreasing tensile strength at the latter temperature. Tests have also been extended to higher temperatures2 for the purpose of determining the most suitable forging range. This temperature range is also of theoretical interest. The phenomenon if increased tensile strength and decreased ductility .in the so-called "blue-heat" range, approximately 200" to 300" C., is well known. It was suggested to the Bureau early in 1926 that a study of the properties of rail steels in this temperature range might prove of interest in relation to the studies of transverse-fissure failures in rails. There were available from another investigation3 several new rails from several different heats made to approximately the same specification requirements, the complete manufacturing histories of which were known. It was decided to determine, at least in the preliminary series of tests, only the ultimate tensile strength, elongation and reduction of area, because of the difficulty, time and cost involved in determining the proportional limit and yield point at elevated temperatures.

Jan 1, 1930

A permanent exhibition of mining machinery has just been opened in the Grand Central Palace, New York City. The exhibits include: Aerial tramways, amalgamation, assaying and laboratory appliances and supplies, blast furnaces, coal, coal-breaker plant, coal excavation, coal products, compressed-air plant, concentrating, crushing, cyanidation, distillation, drainage and pumping, drilling, earth excavation, electrical supplies, explosives, fire prevention, flotation, general supplies, hoisting, hygiene, welfare, iron products, leaching, mechanical conveyors, metal products, natural gas, petroleum, petroleum products, electric, steam, hydraulic, gas, air, and internal-combustion engines, power machinery, preparation of coal, pumping, refining, roasting, rock excavation, rotary drilling; boring, safety appliance, screening and washing, sizing and classifying, smelting, storage of coal, storage of petroleum, surface transportation, surveying, underground timbering, underground trans-port, ventilation, mine. This exposition is operated by the Merchants and Manufacturers Exchange of New York for the purpose of showing under one roof all lines of machinery and mechanical appliances. As for as possible, the exhibits will be shown in operation. The Advisory Committee is as follows: General Howard R. Ward and H. C. Parmelee. Coal and Coke.-Prof. H. H. Stoek, Samuel A. Taylor, Edwin Ludlow. Petroleum and Gas.-Frederick G. Clapp, Ralph Arnold.¬ Extraction of Metals.-Charles W. Merrill, E. Gybbon Spilsbury. Refractories.-Kenneth Seaver.

Jan 12, 1919

By W. J. C. Venter

The use of activated carbon to improve the selectivity in the separation of base metal minerals from bulk concentrates played an important role in the development of separation techniques employed at Tsumeb and Kombat mines. The Kombat mine, owned and operated by Tsumeb Corp. Ltd., is located in the Otavi Valley in the northern part of South West Africa, approximately 213 air miles north of Windhoek and 38 air miles south of Tsumeb, at latitude 19° 43'S and longitude 17º 41'E. The mine is linked to all major centers by both national railroad and tarmac highway systems which pass right through the town. The Otavi Minen- and Eisenbahn-Gesellschaft (OMEG) mined ore on the farm Asis from 1908-1925. Tsumeb Corp. Ltd. acquired the mineral rights in 1947, started diamond drilling in 1954 and commenced mine development in 1960. The mill started production in 1962 when proven ore reserves were 3,378,084 st containing 2.85% Cu and 2.90%Pb. Annual production of 248,411 st was increased in May, 1967 to the rate of 422,990 st, which was still being maintained in 1971, when ore reserves stood at 3,054,701 st of grade 1,91% Cu and 2.5% Pb.

Jan 4, 1973

By F. R. Hensel

ACCORDING to statements by Guertler,1 Smith and Hamilton were the first to study the copper-titanium alloys, but owing to the presence of large amounts of impurities their data are inconclusive. M. A. Hunter and I. W. Bacon later investigated the electrical conductivity and the temperature coefficients at room temperature. The present writers reported their results2 in November, 1930. Recently Droll published data on copper-titanium alloys3 which agree closely with those obtained by the authors. MATERIAL TESTED The titanium used was in the form of square sintered rods, the analysis of which runs as follows: titanium, 95.4 per cent; silicon, 0.7; iron,1.8; aluminum, 1.4; copper, 0.1; manganese, 0.05. . The ingots were prepared in a high-frequency induction furnace in air atmosphere. Their analyses are given in Table 1. Up to 5 percent titanium the alloys could be forged. Above that amount they were red short and broke up easily. Owing to their rapid absorption of nitrogen and oxygen from the air, the alloys with the higher amounts of titanium tend to form surface films which greatly increase the casting difficulties, especially when small masses of metal are handled. It was, however, possible to prepare sound ingots up to 25 per cent titanium.

Jan 1, 1931

By Howard L. Hartman, Burke O. Trafton

There is a fruitful area of computer competence which has gone virtually unnoticed by the mining industry. This is in the solution of its numerous fluid-flow distribution problems, involving the circulation of air, water and other fluids in conduits through mines. Typical of these is the mine ventilation system, which circulates air through mine openings to the working faces. The networks of interconnected airways in large mines-often resembling a tortuous maze or labyrinth defying representation by schematic, let alone solution-must somehow be resolved and analyzed, if effective and safe control of the ventilation is to be maintained. These are admirably suited to programming for solution by high-speed electronic computer. Not only can direction of flow be determined but quantity and head loss as well. EARLIER EFFORTS AT NETWORK SOLUTION The only prior attempt to solve mine ventilation networks by digital computer methods was made by a Japanese investigator1 in 1958 whose work went unpublished. Unfortunately, he employed a method of network analysis little used in the United States and one which could accommodate a maximum of only 30 airways. While his analysis seems unnecessarily cumbersome and involved, it did suggest that a digital computer approach was feasible.

Jan 9, 1963

By James H. Allen

The development of large diameter rotary drilling techniques and equipment in the last nine years has been the main factor for the rapid advancement made by this method of shaft construction. In 1959, less than 5000 ft of large diameter hole was drilled in the United States for the mining and construction industries. By 1967, large diameter hole footage had increased to 117,000 ft. Part of the increase in footage for holes drilled represents AEC requirements due to the discontinuance of atmospheric testing of nuclear devices. The increase in footage for holes drilled for the mining industry can be attributed to cost savings of shaft construction by rotary methods as compared to conventional blasting methods. Until the late 1950's most large diameter holes were drilled with positive displacement rig pumps or air compressors, direct mud or air circulation, conventional sized oil well drilling strings, and multipass reaming techniques. In some very soft formations it was possible to run a pilot bit with one or more hole openers in tandem to drill the hole in a single pass. The main problem with single pass drilling using tandem hole openers was in providing sufficient circulation fluid for proper hole cleaning through conventional sized drill pipe.

Jan 11, 1968

By Herbert Dumont

Since 1947 Preussag AG Metal1 has used a process for fuming zinc- and lead-containing dump slags and residues from vertical retorts in a half-shaft furnace at their Hüttenwerk Harz at Oker. Contrary to the classic shaft furnace, only one side of the half-shaft furnace is fitted with tuyeres. The opposite side is a bricked slope. The upper shaft section is piped. There zinc vapor and combustion gases are burned by sucked-in air. Gases and fume enter a boiler located on the rear length of the furnace via a piped fire bridge. The gases are then cooled in an air preheater prior to dedusting in a bag filter. The furnace is charged with briquettes of metal-bearing materials, coal and pitch. The leaded zinc oxide fume is comparatively rich in both lead and zinc. The copper in the feed is recovered in low-copper matte. The slag can be discarded. The Oker plant comprises 13 furnaces of 2.9 to 4.9 m length in the tuyere area. Two other plants in Italy and Spain are processing zinc leach residues by this technique. Fuming of zinc-lead-oxide ores as well as partially roasted sulfide- zinc-lead-copper bulk concentrates will be possible.

Jan 1, 1970

By D. O. Noel

IT is, of course, expected that manufacture of the various metal powders should involve numerous methods adapted to the specific characteristics of the metals themselves. Several methods for powdering a particular metal may be available, but the physical characteristics of the powder as produced by the several methods may be quite different. In the final analysis, the application of the metal powder dictates the physical properties that the metal powder must possess, and this, to a very large extent, will determine which of several possible methods of manufacture is adopted. Sometimes powder of the same metal is produced by more than one method, each powder having specific characteristics that make it particularly suitable for its application. For purposes of classification, the various methods of powdering metals can be grouped as follows: 1. Machining. 2. Milling (by ball mills, stamps, attrition mills, etc.). 3. Shotting (pouring molten metal into water, air, etc.). 4. Granulation (by stirring molten metal while solidifying). 5. Atomizing (disintegrating by steam, compressed air, etc.). 6. Condensation of metal vapor. 7. Reduction of oxide powders. 8. Chemical precipitation. 9. Electrolytic deposition. 10. Sintering (for producing alloy powders). 11. Formation of an alloy followed by dissolving or otherwise remov-ing one of the alloying constituents.

Jan 1, 1938

Raphael PUmpelly, who became a member of the Institute in 1871, the year of its organization, and retained his membership for a long period, died at his home in Newport, R. I., Aug. 10, 1923. He is survived by a son, Raphael, Jr., and by two daughters, one of whom is the wife of Prof. Henry L. Smyth, of Harvard. Doctor Pumpelly was born in Oswego, N. Y., in 1835. He studied sciences and mining engineering in Paris and at Freiberg, later taking his Doctor's degree at Princeton. He was Professor of Mining at Harvard from 1866 to 1873. Doctor Pumpelly made geological explorations in many lands. In 1861-63, he conducted a scientific exploration for the Japanese government, and for two years thereafter carried on researches in central, western, and northern China and Mongolia. In 1864-65, he undertook a voyage of exploration across the Gobi desert, returning to Europe through Siberia. He was State Geologist of Michigan from 1869 to 1871; Director of the Missouri Geological Survey from 1871 to 1873; and Chief of Division, U. S. Geological Survey, directing the mineral industries division of the tenth census. He organized and directed the Northern Transcontinental Survey, 1881-84; directed the explorations inaugurating the iron ore industry of most of the ranges of Michigan and Western Ontario, 1897-1901; initiated and directed a physical-geographical and archeo-logical exploration of Central Asia under the auspices of the Carnegie Institution of Washington, 19034.2.

Jan 1, 1924

By T. Sterry Hunt

I HAVE already referred to this interesting locality in the opening address, but at the request of some of the members of the Institute, brought before them specimens of the ore and the accompanying rock. The ore, which is cassiterite, is also met with elsewhere in Maine, at Paris and Hebron, but it there occurs associated with orthoclase, quartz, tourmaline, and beryl, in concretionary granite veins, which cut the micaceous gneisses of the White Mountain series. At Winslow the veins traverse an impure gray micaceous limestone, which is found in many parts of this region, and is subordinate to the same gneissic series. The veins, which are seldom more than an inch or two in thickness, are abundant through a considerable breadth of the rock, and are interlaminated with it, occupying places between the sedimentary layers, which are distinctly marked by different shades of color. Occasionally, however, they cut across the stratification for a little distance, showing that the disrupting action was not always confined to tearing the layers apart. The vein-stone consists of purple fluor-spar, and silvery white mica with quartz. In this gangue the cassiterite, nearly black in color, is disseminated in small crystalline masses, sometimes one-half an inch in diameter, and is associated with a little mispickel. I have only seen the veins as exposed at a single point, but was informed that similar veins holding the ore are met with at a distance of several thousand feet

By W. J. Babyak, F. N. Rhines

It has long been supposed that, regardless of the mechanism by which grain boundaries increase the hardness of a ductile metal, the effect should be linearly proportional to the grain boundary area. At the present time two methods for determining grain boundary area in an isotropic aggregate are available. The first, derived by Angus and Summers,' presumes that the grain boundary area is equal to 3vn, where n is the number of grains per sq mm in a random section through the metal. This estimate is based upon the assumption that the grains are equivalent to cubes whose faces correspond with the grains as observed in the micro-section. Measurements on copper, bronze, and a brass showed that a nearly linear relation exists between 3vn and hardness. This is illustrated, for the case of brass, in Fig. 1. The second method, developed independently by Smith and Guttman2 and by Duff in, Meussner, and Rhines,3 is absolute and employs a simple linear intercept count for measuring grain boundary area. It involves no assumptions with respect to the shape and distribution of the grain boundaries. The total surface in unit volume is 2 NL , where NL is the number of intercepts between grain boundary and unit length of a test line passed randomly through the sample. In practice, NL,, the average number of grain boundaries intercepted by unit length of traverse across a prepared microsection, is ob-

Jan 1, 1961

By T. Sterry Hunt

I HAVE already referred to this interesting locality in the opening address, but at the request of some of the members of the Institute, brought before them specimens of the ore and the accompanying rock. The ore, which is cassiterite, is also met with elsewhere in Maine, at Paris and Hebron, but it there occurs associated with orthoclase, quartz, tourmaline, and beryl, in concretionary granite veins, which cut the micaceous gneisses of the White Mountain series. At Winslow the veins traverse an impure gray micaceous limestone, which is found in many parts of this region, and is subordinate to the same gneissic series. The veins, which are seldom more than an inch or two in thickness, are abundant through a considerable breadth of the rock, and are interlaminated with it, occupying places between the sedimentary layers, which are distinctly marked by different shades of color. Occasionally, however, they cut across the stratification for a little distance, showing that the disrupting action was not always confined to tearing the layers apart. The vein-stone consists of purple fluor-spar, and silvery white mica with quartz. In this gangue the cassiterite, nearly black in color, is disseminated in small crystalline masses, sometimes one-half an inch in diameter, and is associated with a little mispickel. I have only seen the veins as exposed at a single point, but was informed that similar veins holding the ore are met with at a distance of several thousand feet.

Jan 1, 1873

By C. G. Dunn, J. L. Walter

COULOMB' and Coulomb and Lacombe2,3 have recently discussed secondary recrystallization in soft iron (99.5 pct Fe). They found that the appearance of this phenomenon was dependent on both the presence of impurities and the thickness of sheet specimens. They concluded that impurities such as carbon, sulfur, and oxygen in the soft iron stabilized the matrix structure and allowed growth of a few grains of specific orientations. They also found that secondary recrystallization ceased when the final thickness was small and attributed this complete inhibition of growth in thin sheet to the restraining action of thermal grooves. When purer iron (99.99 pct Fe) was used, normal grain growth but not secondary recrystallization was obtained. On the other hand it is known that the necessary stabilization of the matrix structure for secondary recrystallization in high-purity silicon iron probably does not depend on impurities but more likely results from the specimen thickness effect of Beck et al.,4 according to evidence and ideas advanced by Walter and Dunn,5,6 and Detert.7 Furthermore, Mullins8 has indicated that if a gas-metal surface energy difference exists across a grain boundary equal to or greater than about 3 pct of the grain boundary energy, then such a grain boundary should not become stuck. Similarly, Walter and Dunn have estimated that any increase in restraining force due to increased thermal grooving with decrease in

Jan 1, 1962

By Andrew Button

INTRODUCTION This review deals with the controls exerted by unconformities on the stratigraphic and areal distribution of gold (and uranium) in Precambrian conglomerates. The relations described are drawn mainly from Precambrian basins in southern Africa, particularly the Witwatersrand Basin. The mining industry of South Africa started in earnest with the discovery of diamonds in 1866. Gold was first discovered in 1870, and in March of 1886, two out-of-luck prospectors stumbled across what was to become the world's greatest goldfield, in the vicinity of Johannesburg. George Harrison and George Walker sold their claims for a pittance and were heard of no more. The Witwatersrand goldfield has been in continuous operation since that time, some 150 mines having operated at one time or another. Deep mining technology developed here has allowed operations to proceed to depths approaching 13,000 feet. The Witwatersrand has produced some 55% of all the gold ever mined, and currently produces 60% of the world's supply, some 650,000 kg Au per year. To 1971, the Witwatersrand had produced some $32 billion of gold and $2 billion of uranium (when average prices were less than $35/oz. for Au and $10/lb. for U308). At present prices, the annual Witwatersrand production of close to 700,000 kg would be worth about $10 billion. Uranium was discovered in the Witwatersrand in 1923. In the $15-30/lb. bracket, the basin contains a reasonably assured plus

Jan 1, 1983

By A. N. Winchell

Petrographic studies of over 1400 rock and mineral samples, and studies of their field relations, show that there is a complete gradation between sandstone and limestone; the lime-silicate rocks were produced by recrystallization of limestone; mineralization and silicification occurred after silication and at considerably lower temperature; carbonation occurred at still lower temperatures. IN CONNECTION with law suits between mining companies at Bingham, Utah, a few years ago, the writer made petrographic studies of more than 1400 rock and mineral samples in thin sections, and also careful studies of their field relations. In petrographic studies, even when an area is studied intensively, attention is commonly centered very largely on the unusual features of special interest, so that the relative abundance of rock types (or minerals or textures) can only be determined by a study of map areas outlined largely by field methods, and cannot be based directly on microscopic work. It is very uncommon, and usually impossible, to take samples at regular short intervals along and across formations. It is precisely because such methods were used at Bingham that the work presents a rare opportunity for determining, on a microscopic basis, the relative abundance of rock types and the continuity of gradations between rock types. At the same time, a study was made of the alteration of sediments under the influence of igneous intrusions, with results that are believed to be of interest and importance.

Jan 3, 1924

M. A. SCHEIL (presented in written form).-Messrs. Franks, Binder and Brown are to be congratulated for the splendid paper that they have presented. We have not made stress-corrosion tests with the cantilever type of specimen which they describe, but it is well known that a uniform stress across a certain portion of the gage length can be obtained with such a specimen. This type of specimen would appear quite expensive to make. The writer was interested in the authors' remarks concerning the erratic results obtained from specimens with cold sheared edges. It might be of general interest to record here some results we obtained with annealed sheet N4 in. thick of type 304 stainless steel. After specimen No. 4 had been exposed 65 days without any signs of cracking we applied a strain gage and measured the stress as 25,810 psi. This value is considerably higher than we find for some of the type 347 stainless alloys and suggests that 18-8 might have a different threshold value for stress-corrosion cracking than 18-8 columbium. The test data in Table I show that strain caused by cold work or polishing has a pronounced effect in lowering the time for failure. In my paper I showed values of 8 hr. and 17 hr. to stress crack cold-rolled type 301 stainless steel stressed beyond the yield point. This steel contained 8.31

Jan 1, 1945

By Charles Fettke

IN THE present day manufacture of glass nearly pure quartz sands are used almost exclusively as the source of the silica, which is the major constituent of all common varieties of glass. Ordinary soda-lime, such as bottle, common tableware, plate, and window glasses, contain from 65 to 75 per cent. of silica. OCCURRENCE Glass sands occur in nature either in the form of loose, unconsolidated sediments or in deposits in which the individual grains have been more or less thoroughly bound together by some cementing agent so as to form sandstones. While deposits of sand and sandstones occur both widely and abundantly distributed, deposits that are sufficiently free from other constituents than quartz grains, so that they can be employed in the manufacture of the better grades of glass, are, comparatively speaking, of rare occurrence. The major portion of the glass sand produced in the United States comes from sandstones. In order to be suitable for glass sand, they should be rather friable. The rock should break down readily along the cementing material between the grains and should not break across the grains rather than along the bond. Some of the sandstones used are so friable that only light shots of slow-burning dynamite are necessary to disintegrate them sufficiently for hydraulic mining, while others have to be passed through crushers in order to disintegrate the rock into its individual grains.

Jan 2, 1926