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By Daniel R. Shawe

Ore deposits of the western U.S. are divisible broadly into two genetic groups, a smaller one that fits the plate tectonic model of subduction and a larger one that appears unrelated to subduction. Some of the middle Paleozoic and lower-middle Mesozoic ore deposits in the western U.S. are associated with eugeosynclinal rocks and lie a few hundred kilometers west of reconstructed continent margins. These deposits probably formed as a result of subduction beneath oceanic or thin continental crust that was analogous to subduction predicated for the Kuroko massive sulfide deposits of Japan. Some middle Mesozoic porphyry copper deposits may have formed east of the continental margin when subduction-generated magmas were emplaced high in continental crust in a manner analogous to subduction-generated magmas that formed the Andean porphyry copper deposits. Most Cretaceous-Cenozoic ore deposits lie in a broad region extending many hundreds of kilometers east of the continent margin and characterized by conjugate tectonic zones, high terrestial heat flow, and low seismic velocity in the upper mantle. The deposits likely were formed in relation to magmas generated along the conjugate tectonic zones during differential northwestward drift and internal wrenching of the continental plate.

Jan 1, 1978

By T. Suganuma

Mitsubishi-Cominco Smelting Co. is a joint venture of Mitsubishi Metal Mining Co. Ltd. (M.M.M.) of Japan and Cominco Ltd. of Canada. The smelter, which is located alongside M.M.M.'s Naoshima copper smelter, was completed in May, 1966 and has a capacity of 36 000 metric tons per year of refined lead. The concentrate feed for the smelter from Pine Point Mines Ltd. is high grade with low impurities; particularly silver, bismuth, antimony, and arsenic, which facilitated a simple plant layout and operation. Concentrate, fluxes, recycle granulated slag and return sinter are drawn from bins by automatic control over weigh belt feeders, sintering is carried out on a 20 m2 Lurgi updraught sintering machine, furnacing in a 3.0 m x 1 ½ m water jacketed blast furnace equipped with an Asarco continuous tapper, refining in four 120 metric ton kettles and casting on a 25 metric ton/hour automatic casting machine. The S@ gas from sintering is cleaned in a high temperature baghouse utilizing glass bags and is then delivered to the M.M.M. copper smelter acid plants. The furnace gases after cleaning in a low temperature baghouse are vented to atmosphere.

Jan 1, 1970

By J. A. Cordier

USINOR has conducted four blast furnace tests with formcoke made from marginal coals in the pilot plant of HBNPC ("H. B. N." process) in four different blast furnaces of various sizes and with medium and high grade burdens. The tests in which up to 30% of the blast furnace fuel burden was replaced by HBN formcoke yielded good results on furnaces ranging in hearth diameters from 5.6 to 9.5 m. The tests demonstrated that: - the slight increase of pressure drop in the stack did not prevent smooth operation at record production rates with the same blowers - the total coke rate was not significantly affected, but there was a slight increase of the calorific value of the top gas - the hot properties of the formcoke are satisfactory as seen from the samples withdrawn at the tuyeres and tapholes. At the end of the two months test on BE nº 2 of Dunkerque, the hearth was as permeable and clean as with good standard coke. Our conclusion is that HBNPC formcoke made from lean coals is an adequate substitute for conventional coke in the range of 20 to 40% replacement, which is of interest to USINOR.

Jan 1, 1977

By Kenneth E. Mathews, Ross D. Hammett, S. Byron Stewart

Theoretical models have been important throughout the history of engineering as a means of understanding past experiences and predicting future performance. Most modelling involves assumptions and a degree of idealization, and it is shown that it is important that the effects of these be recognized when making use of models. One of the principal concerns in underground mining is the effect of the excavations on the states of stress in the rock adjacent to these excavations. As mining proceeds to depth, stress concentrations may be sufficiently high to cause inelastic behaviour of the rock and yielding along joint surfaces. At this stage, attention must be given to the sequencing of the mining process to ensure that the ground control techniques applied are optimized. Increasing use is being made of computer modelling techniques to assist with design. Three case studies are presented to illustrate the application of computer models in mine planning and ground control. In all cases, the data available for design was limited, but the mines were fully developed and openings could be inspected. The mining methods studied are cut and fill stoping, room and pillar stoping, and longhole stoping.

Jan 1, 1983

On Wednesday evening, Jan. 27, 1915, were held in the auditorium of the Engineering Societies Building the inaugural exercises of The Engineering Foundation, established by the United Engineering Society. The initial gift to the Foundation of $200,000, made by Ambrose Swasey, Past President of the American Society of Mechanical Engineers, was formally accepted at this time. So far as known this is the first instance of a foundation devoted to engineering purposes. This meeting con-stituted also an appropriate tribute to the generous gift made to the Foundation and gave opportunity for expression of the satisfaction and approval which are felt by engineers everywhere at the establishment of a means of promoting the good of mankind through the work of the engineer along the broadest lines. Gano Dunn, President of the United Engineering Society and Past President of the American Institute of Electrical Engineers, acted as presiding officer, and on the platform were seated representatives of the three societies constituting the United Engineering Society, and of the American Society of Civil Engineers. Members of the four societies and many other friends interested in the profession composed the audience.

Jan 3, 1915

By R. R. Sayers

VENTILATION may be defined as the process by which vitiated air of an inclosed or partly inclosed space is continuously replaced by fresh air. Fresh air has been defined as invigorating pure air. Pure dry air at sea level contains the following gases:1 Analysis of Air at Sea Level PER CENT. Oxygen 20.94 Nitrogen 78.09 Carbon dioxide 0.03 Argon 0.94 Helium, krypton, neon, xenon, hydrogen, hydrogen peroxid, ammonia, ozone traces CARBON DIOXIDE LIMIT For many years carbon dioxide was used as an index of the purity of the air vitiated by the metabolism of people. It was, however, well known that the untoward effects produced on those exposed to such air was not due to the concentration of the carbon dioxide. It has been found that the untoward effects on the comfort and efficiency of those so exposed are due to the increased temperature and humidity. It has been found that men can breathe air containing many times the amount of carbon dioxide found in our worst ventilated theaters and assembly halls, which, according to Rosenau, do not contain above 0.5 per cent. carbon dioxide.

Jan 7, 1926

By A. P. Coldren, V. Biss

SINCE the r ? a transformation rates of many carbon-free ferrous alloys and low-carbon alloy steels are relatively fast, conventional equipment is not suitable for the dilatometric determination of continuous cooling transformation diagrams. On the other hand, a method based on metallographic analysis of quenched specimens would not be practicable because the various products of shear-dominated transformation are essentially indistinguishable in low-carbon iron-base alloys. Both problems may be avoided by a thermal analysis method employing gas quenching of small specimens austenitized in vacuo. The laboratory equipment employed in the present study consisted of a Tektronix Type 564 Storage Screen Oscilloscope and a Kinney high-vacuum evaporator, modified as shown in Fig. 1, to permit heating a small specimen and cooling it slowly by programmed cooling or rapidly (up to about 8000°F per sec) by a controlled quench with helium gas. The oscilloscope records the electromotive force of a 40-gage (0.003-in.-diam) Chromel-Alumel thermocouple in the specimen during cooling. The temperature at which the cooling curve begins to show the influence of the heat produced by the phase change in the specimen was arbitrarily taken as the transformation-start temperature.*

Jan 1, 1970

By H. M. Chance

THE great outspread of the coal measures over portions of thirty-one of the sixty-seven counties Of Pennsylvania, and the large number of workable seams comprising the coal series, together with some workable seams lately shown to belong to the (so-called) barren measures, create the impression that these fields contain a practically inexhaustible supply of fuel, and those who have estimated or attempted to estimate their available tonnage have generally promulgated this view. But the actual total contents of this coal-field is of no importance to us at present; calculations including all seams, whether thick enough to mine or not, whether pure enough to furnish a marketable fuel or not, whether accessible at reasonable depth or not, are of no practical value. As coal producers, we are interested not in the total contents, but in the total amount of easily accessible coal of good quality con-tained in beds thick enough for remunerative mining. The estimates contained in this paper refer exclusively to workable and accessible coal of commercial value, we may call it "available" coral. I am not aware, that any one has as yet attempted to estimate in

Jan 1, 1882

By O. W. Ellis

IN VIEW of the extensive use of the brasses and bronzes in engineering practice it is indeed surprising that so little scientific work has been done on the oxides in these alloys. Recognition of the ill effects of these compounds is universally accorded, both in foundry procedure and in such specifications as cover the melting of these useful mixtures. In the latter, limits, for example, are placed on the proportions of scrap metal in the charge, and clauses governing the use of fluxes are included, the addition of fluxes to the charge being made with the object of avoiding oxidation during the process of melting and of subducing and separating non-metallic matter from the melt.1 In the manufacture of brass it occasionally, though rarely, occurs that the virgin metals, copper and zinc, alone are used. In the event of virgin metals being employed, that of the higher melting point is always melted first. If it is melted under suitable conditions, little or no oxidation will occur. Whether oxidation has occurred or not, however, can best be determined by microscopic examination of a sample taken from the melt.

Jan 1, 1930

By E. DeGolyer

THE petroleum production of the world for 1924 again passed the billion-barrel mark, as it did in 1923. A preliminary estimate of production is 1,016,000,000 bbl., a decrease of 1,100,000 bbl., or less than 1 per cent. from the 1,017,100,000 bbl. produced in 1923, the year of greatest production. FIG. 1.-TOTAL WORLD AND UNITED STATES PRODUCTION. Production in the United States decreased 18,500,000 bbl., the. first decrease in yearly production since 1906. Mexican production decreased almost 10,000,000 bbl. Russia, Persia, Roumania, Venezuela, and Peru increased their production by an amount almost great enough to offset the decline in the United States and Mexico. The decline in the production in the United States and Mexico was considerably less than anticipated by leading geologists, economists, and statisticians; nor did the increase in consumption entirely meet the expectations of estimators. Early in the year, the statistical department of one of the most important oil companies forecast a draft on stocks, from an excess of demand over supply, of about 80,000,000 bbl. Instead of decreasing our stocks, they were increased by about 33,000,000 barrels.

Jan 3, 1925

By C. W. Clark

Two papers have been written previously concerning operations at the Montreal East plant of Canadian Copper Refiners Limited. The first one,1 written in 1932, described silver-refinery operations at the time for producing silver and gold bullion from tankhouse anode slimes; the second,2 published in 1933, consisted of a description of the entire plant. Since publication of these papers the refinery has become the world's larg-est producer of refined selenium. The first selenium was produced in August 1934. Tellurium production on a. commercial scale followed in October 1935. This paper will deal with selenium and tellurium produc-tion and also with present operations in the silver refinery. Blister cakes from Hudson' Bay Mining and Smelting Co., Flin Flon, Manitoba, and commercial anodes from Noranda Mines Limited, Noranda, Quebec, are refined at Montreal East. Both these bullions have unusually high gold, selenium and tellurium content. The average assay of raw slimes produced from domestic and Noranda anodes is about 40 per cent Cu, 3600 oz. per ton Ag, 800 oz. per ton Au, 22 per cent Se and 3.7 per cent Te.

Jan 1, 1938

By R. R. Sayers

VENTILATION may be defined as the process by which vitiated air of an inclosed or partly inclosed space is continuously replaced by fresh air. Fresh air has been defined as invigorating pure air. Pure dry air at sea level contains the following gases:1 Analysis of Air at Sea Level PER CENT. Oxygen 20.94 Nitrogen 78.09 Carbon dioxide 0.03 Argon 0.94 Helium, krypton, neon, xenon, hydrogen, hydrogen peroxid, ammonia, ozone traces CARBON DIOXIDE LIMIT For many years carbon dioxide was used as an index of the purity of the air vitiated by the metabolism of people. It was, however, well known that the untoward effects produced on those exposed to such air was not due to the concentration of the carbon dioxide. It has been found that the untoward effects on the comfort and efficiency of those so exposed are due to the increased temperature and humidity. It has been found that men can breathe air containing many times the amount of carbon dioxide found in our worst ventilated theaters and assembly halls, which, according to Rosenau, do not contain above 0.5 per cent. carbon dioxide.

Jan 7, 1926

By J. B. Stubbins, D. F. Coates, K. L. McRorie

Twenty-two pit slides that occurred in two Canadian open pit mining properties are analyzed. Information on the results of laboratory tests of the rocks and a brief description of the geological environment are also presented. One deduction from the study is that slides seem to be predictable by using established theory. This corroboration indicates that, contrary to normal mining practice, the appropriate slope angle should vary with the height of the wall. In addition, if the general ground water level around an open pit can be reduced, the appropriate slope angles of the walls could then be increased by a determinable amount. The ultimate objective of these investigations is to determine the relationship between the percentage probability of failure of any slope designed with specific strength paraheters. With this relationship it would then be possible to determine optimum slope angles. Because of changes in various economic factors, open pits are now being mined to much greater depths than previously. The need to keep stripping ratios low without endanrrerine.-- lives and equipment provides a strong incentive to determine the maximum practicable wall slopes. Applied research work is currently being conducted to establish the methods for analyzing optimum slopes.

Jan 1, 1963

By Frank E. Shepard

Electric power in mining-operations is now successfully applied to haulage, hoisting, lighting and pumping; and until lately, drilling was the one department of mining in which an electric source of energy had not been introduced. Drilling by electric power has been the field for much investigation and several forms of electric-drills have been tried; but in the severe service of rock-drilling many dieculties have been encountered, and the heavy cost of repairs has caused a deep prejudice against this system of drilling. In the majority of electric rock-drills previously placed on the market, two principal factors have been considered; first, a portable electric motor usually of heavy pattern, coupled to the driving-mechanism of the drill proper by means of a flexible shaft; and second, the coupling of some form of reciprocating cross-head to a piston by means of a spiral spring, the drill-bit being fastened to the piston-rod by some suitable form of chuck with fastening bolts and nuts. In this latter form of drill, the cross-head has a fixed stroke, while the piston with drill-bit attached is allowed a variable stroke through the

Jan 1, 1904

By C. A. Crawford

NICKEL and the nickel-copper alloy, the latter generally referred to as morel metal, are available in a variety of wrought and fabricated forums, of which the following are regular commercial products: Form Monel Metal Pure Nickel Roc Hot-rolled; round, hexagon, Same as morel metal square, and flat shapes Cold drawn; round, hexagon, square, and flat shapes Hot-rolled wire rod Cold-drawn wire rod Plates Hot-rolled Same as morel metal Sheets Hot-rolled annealed Same as morel metal Hot-rolled annealed, pickled Full-finished Full-finished, No. 3 grind one side Full-finished, No. 4 grind one side Cold-rolled (annealed) Cold-rolled, No. 5 polished finish Strip Hot-rolled (flat rods) Same as morel metal Cold-rolled (annealed) Cold-rolled (unannealed) Tubes and pipe Gas-welded tube Seamless tube Seamless tube in I. P. S. Gas-welded tube Forgings Bolts, rivets Same as morel metal Nuts and washers Forging to order Castings Sand castings Same as morel metal Centrifugal castings Electrolytic Cathodes of high purity Anodes Cast anodes Rolled anodes Shot and block for 25 to 50-1b. pigs 5, 25 and 50-1b. pigs melting. Shot Shot

Jan 1, 1927

By D. J. Jr. McAdam

PART I. OUTLINE OF INVESTIGATION, DESCRIPTION OF MATERIAL AND METHODS RESULTS of investigation of corrosion-fatigue of metals at the U. S. Naval Engineering Experiment Station, Annapolis, Md., have been discussed by the writer in several recent papers.1,2,3,4 In those papers references were also given to the work of Haigh in 1917.6 Efforts by the writer to obtain a better understanding of some of the factors involved in corrosion-fatigue finally developed into a general investigation of the effect of time and cyclic stress on corrosion of metals. Corrosion fatigue of Metals As described in the papers mentioned, rotating-cantilever specimens, conically tapered so that the stress is nearly uniform over a length of about 1.5 in., were subjected to simultaneous fatigue and corrosion. For this purpose a stream of water was diagonally applied so as to sweep the specimen from the outer to the inner fillet and surround the stressed surface with water. The fresh water is a calcium carbonate water, the composition of which has been given in a previous paper.2 The salt water is Severn River water having a saline content about one-third that of sea water.

Jan 1, 1928

By R. I. Jaffee, F. C. Holden, H. R. Ogden

The properties of quenched Ti-Fe alloys have been correlated with their microstruc-tures. For specimens quenched from equilibrium in the a-ß field, the dominant micro-structural variable is the a-ß ratio. A comparison of specimens having equiaxed a-ß structures with those having acicular a-ß structures shows that the equiaxed specimens have better tensile ductility, but lower impact resistance. There is evidence to show that specimens with acicular structures reach equilibrium in the a-ß field more rapidly than specimens with equiaxed structures. Both strength and ductility are lowered by heat treatments below 700°C. IN previous work,1, 2 certain principles of the physical metallurgy of a-ß titanium alloys have been evolved. Most of these principles have been based on data obtained on alloy systems which undergo no eutectoid reaction, or in which the eutec-toid reaction is so sluggish as to be inoperative. The alloy systems previously studied included the Ti-Mn alloys, with and without a-stabilizing additions, and the binary Ti-Mo alloys. The most important of these principles are: I) The compositional factors which affect mechanical properties are solid solution strengthening, the martensite transformation, and instability of

Jan 1, 1957

By Lennart Wellenius

LAISVALL - ONE OF THE BOLIDEN MINES Until the Aitik Mine (2,000,000 mtpy) started in 1968 the Laisvall Mine (1,200,000 mtpy) was the biggest unit of about 20 producing mines, belonging to the Boliden Company Ltd. As shown in Fig. 1 the mines are spread over a wide area. Most of them are small complex ore mines (50,000 - 300,000 mtpy), for which reason the total mine production does not exceed 5,500,000 mtpy. When our company was invited to present a paper, Laisvall was chosen because it is the biggest European galena-mine in production today. The Laisvall Mine is situated in the county of Norrbotten, Sweden, at the eastern border of the Caledonian mountain-chain. The road distance to Slagnäs, the nearest railway station, is 60 miles. The railway between Slagnäs and BOLIDEN's smelting plant, the Rönnskär Works, is 140 miles long. PRODUCTION STARTED IN 1943 In the Autumn of 1938 a boulder was discovered, consisting of sandstone with galena, on the shore of the Lake Stor-Laisan. The boulder came from an Eocambrian sandstone formation, which is overlain by Cambrian-Silurian rock.

Jan 1, 1970

By H. S. Choi, I. Iwasaki

The effect of temperature as a parameter in ore flotation has not been systematically studied, although for some ores it has been known for many years that selectivity and grade of concentrates can be improved by conditioning or flotation at moderately or substantially elevated temperatures. In 1934 Coghill and Clemmer' stated that "elevated temperature seems to make hard water more tolerable" in soap flotation, and a cursory examination of the literature indicates that some earlier investigators were aware of beneficial results obtained by floating above room or mill-water temperatures. Tartaron,2 Mitchell et aL.,3 and particularly Hamilton et al.' have shown that high pulp temperatures give high recovery and selectivity in soap flotation of fluorite from a variety of gangue minerals. As a result of the work of these and of other investigators, high-temperature flotation has been successfully applied to industrial flotation of fluorite. Falconer" stated: "The use of high temperature conditioning (above 35°C and preferably above 60°C) in connection with the soap flotation of nonsulphide ores, as covered in B. Kalinowski's French Patent No. 847,-215, Dec. 7, 1938, is claimed to provide more intense activation, better separation of values from gangue, and reduction in quantity of reagents." The various investigations quoted above clearly demonstrate the improvements to be realized by increasing the temperature at which fluorite is floated, and it is surprising that little or no information has been published on systematic investigation of the same method as applied to other ores. The present article describes comparative results obtained at room temperature and at elevated temperatures by otherwise conventional flotation of iron ores, by single-mineral flotation in the Hallimond tube, and by contact-angle measurements. It is not the purpose of this article to evaluate the commercial feasibility of high-temperature flotation of iron ores, although preliminary calculations show that the cost should not be excessive and that the gains to be realized may well outweigh the extra cost of heating the pulp. LABORATORY FLOTATION TESTS Experimental: All flotation tests reported in this article that use a laboratory Fagergren cell were made on ore A (either containing the primary slimes or deslimed at 20µ as specified) following the preparatory procedures described elsewhere- or this particular ore. Ore A contained hematite, goethite (limonite), quartz, chert, and minor quantities of magnetite. Confirmatory tests made on other ores show that the same general principles apply to ores of similar mineralogy and structure. Conditioning was performed by adding the collector, as a soap, to the vigorously stirred and heated pulp. Conditioning time was 5 min, the pulp contained 60 pct solids, and the equivalent of 0.5 Ib of fatty acid was added per ton of original (unde-slimed) ore. The pH of the pulps ranged from 6.8 to 7.1 (25°C measurement) during conditioning. The pH was adjusted in the flotation cell by addition of either NaOH or H2SO4, the values reported being those of the pulp cooled to 25°C. During conditioning and flotation the pulp temperatures were controlled within l° to 2° by immersion of Variac-controlled Calrod elements in the conditioning beaker and in the cell, and by the use of water, heated to the appropriate temperature, for transferring pulp, adjusting pulp volume, and washing. Selectivity indexes have been calculated on the same basis as those reported in the article by Cooke, Iwasaki, and Choi." Results: Table I gives the results obtained by floating deslimed ore A with pure oleic acid at 25" and 50°C, and Fig. 1 shows the selectivity indexes plotted against pH of flotation. Inspection of Table I

Jan 1, 1961

By H. C. Chang, N. J. Grant

Creep of very coarse grained high purity aluminum was studied at 400°, 700°, and 1100°F at initial stresses of 50 to 1200 psi. Local strain measurements were made across the grain boundaries and in different regions of various grains during creep, thereby permitting the drawing of component creep curves. The relative amounts of elongation as measured across a grain boundary and in the grains adjacent to the boundary depend on the temperature of testing. The significance of creep curve equations and activation energies is discussed. THIS paper presents some of the results of a research program devoted to the study of the mechanism of creep in high purity aluminum. Previous publications have dealt with the cyclic processes of alternating grain boundary sliding and migration, and the deformation in the grains caused by these processes;' the direction and the driving force of grain boundary sliding and migration;' the deformation in the grains and the restricting effects of the grain boundaries on this deformation." These previous papers were based mainly on either microscopic observations or X-ray data, or both. Sometimes creep curves across two closely spaced reference marks (about 0.6 to 0.7 mm apart) were also presented with a view to correlating the elongation values with the optical observations in general, and with certain deformation processes in particular. These curves shall henceforth be referred to as component creep curves. No attempts were made, however, to compare either the component creep curves which were obtained in different regions of a specimen, or those obtained from different specimens subjected to different creep test conditions. It is the purpose of this paper to present these component creep curves. Among the factors influencing the behaviors of these curves, those studied were stress, temperature, and grain arrangements in the specimens. It is proposed to show how greatly the deformation can vary from grain to grain and within an individual grain in a coarse grained specimen. The experimental technique and procedure have been presented.' It remains necessary to emphasize that the reference marks were produced by pressing a thin sewing needle into the surface of the specimen before the final annealing at 900°F for 24 hr and at 1150°F for 12 hr. The cold work around the needle indentations was therefore removed. The depth of these holes after electropolishing the annealed specimens was about 0.01 mm. This depth and area were negligible in comparison with the thickness of the specimens, 2.3 mm, and hence would not affect the creep behavior. Results Fig. 1 shows a development diagram of specimen P-8. The dots on the surface locate the needle point reference marks used to obtain the component creep curves. A curve obtained between two dots across a grain boundary measures not only the boundary deformation but also the deformation associated with boundary sliding occurring in the grains in the region between these indents. The original distance between two reference marks was about 0.6 to 0.7 mm. The maximum error of measurement was 0.01 mm, or in terms of percentage elongation, of the order of & 1.5 pct. Whereas the component creep curves shown in the figures to follow were drawn as a gross average of the points, in view of the fineness of some of the steps of grain boundary sliding and migration, as shown in the previous publications,¹,2 it appears logical to expect that some of the finer cycles of movement have not been delineated for the strain sensitivity of the measuring system. It seems justifiable to say that the curves are not as smooth as shown. 700°F Tests: Fig. 2 shows component creep curves across four of the grain boundaries in specimen P-8, tested at 700°F and 85 psi. These curves clearly show alternate cycles of increasing and decreasing

Jan 1, 1954