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By George M. Bouton, Lawrence Ferguson

The experiments described in this publication were inspired by the Bell System's large interest in lead-alloy sheathed cables and by the wide range of fatigue and corroding conditions to which they are sometimes subjected in service. The first experiments consisted of operating specimens of lead + I per cent antimony telephone cable sheath alloy in a fatigue test while they were immersed in water taken from a manhole. Because of many published reports concerning corrosion-fatigue phenomena of various metals and alloys, a reduction in fatigue life was expected(1)2 Instead, however, the fatigue test ran on for many times the normal number of cycles an4 was finally stopped without failure. Because of this, the experiments were broadened to include the effect of many media on the fatigue properties of four lead alloys over a wide range of testing speeds and strains. One material, a viscous tacky polymerized isobutylene3 used in

Jan 1, 1945

By Patrick M. Hurley

The relationships between mineral deposits and various plate margin mechanisms are examined under the constraints of radiogenic isotopes and other geochemical indicators. It seems like1 y that: (1) deposits of the spreading ridge association are fairly ubiquitious through most of geologic history and can be recognized by the lithologic assemblage and primitive lead isotope ratios; (2) most metals in the island arc association are not derived entirely from a subducting oceanic plate, and have a partly continental affinity; (3) subduction beneath a continental plate generates ores which are derived either from the downgoing plate or from the lower crust; (4) the heating of a continental plate by thickening or by mantle plumes may develop a metallogenic province involving extraction of metals from the curst; (5) rifts and grabens developing thick sections of marine sediments with evaporites may be the locus of base metal mineralization by movement of reducing brine solutions resulting from diagenesis and bacterial reduction of sulfates

Jan 1, 1978

By C. B. Foraker

THE Magma mine, of the Magma Copper Co., at Superior, Pinal County, Arizona, is 68 miles east of Phoenix and 21 miles west of Miami, Arizona, on highway U. S. 180. Temperatures and Underground Waters Surface Temperatures.—The average surface dry-bulb temperature at Superior is 72.4°; wet-bulb, 57.4°; with an indicated relative humidity of 38 per cent. The average yearly rainfall from 1921 to 1936, inclusive, was 18.74 in. The maximum condition of the atmosphere is in June, July and August, and the minimum is in January and February. The surface temperatures, of course, influence the temperatures of the downcast shafts; however, the variation between winter and summer causes a difference of only 2" to 3" in the stopes and working places that are not close to the intake shafts. Average atmospheric conditions are shown in Fig. 1. Rock Temperatures.—Rock temperatures on the deeper levels of the mine are as follows:

Jan 1, 1940

By C. B. Foraker

THE Magma mine, of the Magma Copper Co., at Superior, Pinal County, Arizona, is 68 miles east of Phoenix and 21 miles west of Miami, Arizona, on highway U. S. 180. Temperatures and Underground Waters Surface Temperatures.—The average surface dry-bulb temperature at Superior is 72.4°; wet-bulb, 57.4°; with an indicated relative humidity of 38 per cent. The average yearly rainfall from 1921 to 1936, inclusive, was 18.74 in. The maximum condition of the atmosphere is in June, July and August, and the minimum is in January and February. The surface temperatures, of course, influence the temperatures of the downcast shafts; however, the variation between winter and summer causes a difference of only 2" to 3" in the stopes and working places that are not close to the intake shafts. Average atmospheric conditions are shown in Fig. 1. Rock Temperatures.—Rock temperatures on the deeper levels of the mine are as follows:

Jan 1, 1940

By AIME AIME

POSSIBILITY of a greatly increased manganese production from domestic source; is indicated by news that the Bureau of Mines has been successful in producing concentrates with high manganese content from the low-grade deposit, in the Las Vegas, Nev.) area. The first unit of the comprehensive group of pilot plants built by the Bureau of Mines at Boulder City, Nev., under a defense appropriation has started operations, demonstrating definitely the applicability of a process developed in the Bureau laboratories. About 12 1/2 lb. of manganese is needed for the production of every ton of steel, and substitution is difficult. The United States produces only about 3 per cent of its total needs of this ore. Only high-grade ore, such as the Russian ore, containing 18 per cent or more manganese, is generally used by American producers in making ferro¬manganese the form in which manganese is usually added in steel manu-

Jan 1, 1941

By Carl E. Williams

A computer program has been developed which will locate the economic limits of an open-pit mine and also designate which ore and waste blocks to remove per period (years or quarters) to maximize the discounted cash flow over the life of the mine. A set of operating constraints was carefully selected so that the following functions are controlled: (1) the removal of overburden by preproduction and production stripping exposes a fixed amount of ore; (2) a constant manpower and equipment usage is insured (except for trucks); (3) the tons of mill ore, concentrate, and stockpiled ore are regulated; (4) the number and extent of shovel moves are minimized; (5) the grindability of the rock is considered as well as the variable haulage cost caused by variable haulage distances and depths; and (6) the size of the shovel working area is regulated. As many as 50 alternate schedules can be produced per computer run. They are arranged in descending order starting with the best solution.

Jan 1, 1975

By F. R. Hensel

The present study was made to determine the laws governing the formation of the primary? crystal structure during solidification. Most of the experiments were carried out on chill castings, but from the resiilts it will be possible to draw certain conclusions as far as sand castings are concerned. It is necessary to discuss first a number of theories, which are generally adopted for explaining the structure of an ingot. Usually, the structure of an ingot consists of the following three zones (Fig. 1): (1) a chill layer of small at-random oriented crystals; (2) a layer of columnar crystals; (3) a zone of equiaxed crystals. The tensile properties of the chill layer and the equiaxed range are usually much better than in the columnar range, particularly the planes that are formed by the columnar crystals growing from two sides at right angles have low tensile properties. This is one of the reasons why columnar crystals in ingot structures are undesirable.

Jan 1, 1937

By Arthur F. Johnson

THE principal costs of making a pound of aluminum are for 9 kw-hr of electricity and for 1.9 Ib of the oxide (A1203) called alumina. A pound of alumina is made by digesting 2 or 3 lb of bauxite in hot caustic solutions, settling and filtering out the oxides of silicon, iron, and titanium and precipitating and calcining the A1203 as a pure, white powder. The cost of foreign bauxite delivered at an alumina plant in the U.S. may equal or exceed the cost of its chemical treatment to make alumina. Some of the principal factors affecting costs in the utilization of foreign bauxites are: transportation from mine to market, mineralogical and physical composition of the bauxite, thickness of the bauxite beds and their clay and forest overburden, amen- ability of the bauxite to beneficiation and to caustic extraction of the alumina, and lastly size of bauxite deposits and rate of mining employed.

Jan 6, 1954

By B. Hyatt, E. Klokholm

The reesistivity of Cu-Pd alloys of 9.6 to 29 pct Pd alloys was measured after plastic deformzation in tension. For all compositions a continzting decrease in resistivity with increasing plastic strain was observed. By comparison with the results of Damask on a brass ad Cu3Au, it was deduced that these anonzalous decreases in resistivity are due to the decrease in short-vunge order caused by cold work. An anomalous decrease in the resistivity of cold-worked CU-Pd alloys was first reported by Jaumot and Sawatzky.' They observed decreases in the electrical resistivity when disordered Cu-Pd alloys drawing at room temperature. Recently, a similar anomaly was reported by Aarts and Houston-Mac-Mi1lan2 in Ag-Pd alloys containing 10 to 45 pct Pd. The plastic deformation in this case was produced by tensile strain at liquid-nitrogen temperatures. For AE-Pd alloys the relative resistivity change becomes positive for tensile strains of about 20 pct.

Jan 1, 1960

By I. Plaskin

Interaction of sulfide minerals and native metals I with reagents in flotation is largely determined by particle-surface changes resulting from action of the medium and dissolved gases. A number of early studies were devoted to the selective action of various gases on minerals.' Mc-Lachlan' paid attention to oxygen as the most active gas affecting flotation properties of sulfide minerals. Opposing views were expressed concerning the influence of sulfide oxidation on xanthate flotation: Taggart3 recognized the positive influence of oxygen, and I. W. Wark4 rejected it. Shvedovh ffered the hypothesis of partial oxidation. As to the influence of such gases as hydrogen" and carbon dioxide on mineral floatability, opinions also differed. Effect of Oxygen on Sulfide Mineral Flotation: Research on the influence of oxygen and other gases on the floatability of sulfide minerals and native metals has been carried out at the Institute of Mining of the USSR Academy of Sciences in

Jan 1, 1960

By Ross W. Smith, Salim Akhtar

INTRODUCTION Flotation of oxide minerals, particularly silicates, with cationic collectors differs substantially from classic flotation of sulfide minerals using sulfhydryl collectors. In the case of cationic flotation of these minerals, in general: 1. There is a greater importance of electrostatic interaction between mineral and collector. 2. Longer-chained collectors are required; as a rule at least 10 carbons must be present in the hydrocarbon chain. 3. Moderate concentration of collector is required. 4. Attachment between collector and mineral appears to be less strong even though the system may exhibit a large contact angle. 5. Required conditioning time before flotation is usually relatively short. 6. There is sensitivity to slimes. 7. The collectors usually possess frothing power. 8. Selectivity of cationic collectors for specific minerals is usually poor. Almost any of the oxide and silicate minerals may be floated using cationic collectors. However, specific response to these collectors varies with mineral type. The following classes and minerals are

Jan 1, 1976

By J. D. Miller, P. J. McDonough, H. Q. Portillo

Previous investigations have demonstrated the catalytic effect of silver additions in the ferric sulfate leaching of chalcopyrite [ ] The enhanced rate of leaching was found to be due to the formation of an intermediate Ag S film which forms on the Cures2 surface by an exchange reaction Under these conditions, unlike the uncatalysed ferric sulfate leach, the elemental sulfur forms a nonprotective reaction product on the Ag S crystallites As a result, the rate appears to become limited by an intermediate electrochemical reaction in {he Ag2S film rather than by transport through the elemental sulfur reaction product [ ] The reaction rate was found to have a complex dependence on the Ag+, Fe++ and Fe+3 concentrations, but independent of the Cu concentration Electrochemical measurements with a Ag,S-coated chalcopyrite electrode provide further information regarding the nature of the reaction mechanism The kinetics of the rate limiting, intermediate electrochemical reaction are analyzed in terms of the Butler-Volmer equation

Jan 1, 1981

By J. R. Campbell

During the past few years, the writer has had occasion to take several excursions into the realms of the washability of beds 3 and 4 of the Pocahontas coal and the proper handling of these coals in prepared sizes Fig. 1.—Washability curve for 4 by 2½-in. egg, PocahoKtas coal. Note that definite break occurs at about 1.60 sp. gr., and washing at this gravity removes all heavy rock and slate, amounting to about 5 per cent. Curve 2 indicates a bony coal, and washed egg coal might not have a good appcarance, and would be condemned by visual inspection, although it would be well prepared mechanically. to attain the greatest realization for the operator and yet produce a market product acceptable to the consumer. Preparation is not new in the southern field, but some new angles have presented themselves in recent years on account of the progress of mechanical preparation. Mechanical methods are entirely devoid of the five senses given to

Jan 1, 1931

By Charles H. Jacoby, Leo E. Read

IN diamond coring salt beds to evaluate deposits, special techniques are applied to standard slim hole drilling to obtain a representative sample of the water soluble sodium chloride. Industrial consumers generally require a run-of-the-mine material of 98.0 pct sodium chloride. Since no commercial beneficiation has yet been devised to upgrade the lower quality salt beds, the only processing is crushing and screening to the size required by the customer. Coring salt sections has recently become important not only in dry mining, but also in the development of brine cavities by hydraulic fracturing and the formation of jugs for storing liquid petroleum products. Drilling Fluid: The fluid used in coring salt beds in New York, Ohio, and Michigan is a thoroughly saturated brine made from 3.0 lb rock salt per gal of make-up water. This mined rock salt, -4 mesh +10 mesh, is dissolved in a lixator, a double-bottomed cone hopper that turns fresh water to fully saturated brine.

Jan 5, 1957

By J. C. Konopka, S. A. G. Poppen, E. K. Roesner

Many shafts have experienced stability problems during shaft sinking because the designer failed to fully appreciate the conditions he would encounter. Some shafts have failed during construction because the ground supports provided to compensate for the expected conditions were inadequate despite the most careful investigations and analyses. To design a ground support which is ultimately safe to achieve stability during shaft sinking would be too costly and impractical and, therefore, many shafts would simply not be constructed. The design of a ground support for shaft sinking based on an intimate understanding of the expected ground behaviour and stress development during excavation combines the art of mining with the science of geotechnical engineering. Where no historical design data is available, the designer of the ground support must: 1. classify the rocks and soils and assess their behavioural characteristics; 2. calculate the primary and secondary stresses; 3. design and/or select a ground support system which will ensure stability of the excavation during shaft sinking.

Jan 1, 1983

By Frederick Prime

AT the last meeting of the Institute, Mr. A. L. Holley read a paper on "Steel," in which he proposes for it a definition so opposed to the one generally received, as to call for some remarks. Until within the last five or six years there has been no dispute on the subject, and it seems worth while to investigate the matter. For not only does a proper tax on all importations depend on a proper appreciation of the term steel, but it is necessary to know whether steel, or wrought-iron, or homogeneous iron are requisite in all processes of manufacture in which malleable iron is employed, on account of cost, strength, etc. Karsteu* says : " Iron may be obtained, either as an unforgeable, unweldable metal, which melts at a high heat, termed cast-iron; or as a ductile, weldable, soft metal, which can only be melted at the * Karsten, Handbuch der Eisenhüttenkunde, 3d ed., vol. i, p. 6. Berlin, 1841.

Jan 1, 1876

By Akira Ishizu, Nobuo Matsui, Hideo Yamamoto, Tatsuya Nagahama

At Kamioka Mine of Mitsui Mining & Smelting Co., Ltd., Japan there are three mills, treating a total of 6400 t/d of lead-zinc Ore. In the lead-zinc bulk differential flotation at Shikama Mill the addition of reagents is automatically controlled by the feed rate, the lead and zinc content in feed, froth and tailing, the pH and the concentration of cyanide ion in the pulp. As the zinc thickener overflow at Shikama Mill contains CU(CN)3--, ZnS, CdS, CN-, xanthate and frother, all the ingredients in the over- flow other than CN are floated by using the Nagahm flotation machine, and the water containing only CN- is effectively recycled to the lead- zinc differential flotation circuit. In the lead-zinc straight differential flotation at Mozumi Mill, the overflow of tailing pond is recycled especially to the cleaning flotation circuit by decreasing the pulp density. Thus the integrated recycling of wastewater greatly reduces environmental problem and in addition, it generates sizeable profit.

Jan 1, 1977

By Rudolph G. Wuerker

WITH the growing complexity of ore dressing processes and the diversity of equipment, efficiency control has become increasingly important in beneficiation. In the case of iron ore dressing, there have been sporadic attempts1-3 to establish the optimum separation for various ores so that grade and recovery would be readily predictable. But no rigorous statistical analysis and graphical presentation of such tests could be found in the literature of this country. Tests Made with Iron Ores Expanding upon existing methods of plant supervision and efficiency control, an investigation was started in the ore dressing laboratory at the University of Illinois on the applicability of distribution analysis to iron ores. A sample of crude ore was obtained from the Ohio mine of Cleveland-Cliffs Iron Co. at Ishpeming, Mich., consisting mostly of alternating bands of hematite and siliceous gangue, both about ¼ in. wide. The ore was heavily coated with limonite, which often filled the cracks.

Jan 7, 1958

By Morris Muskat

ANALYTICAL calculations have been carried out on the effect of casing perforations on the productivity of wells, and formulas have been derived for general types of perforation patterns. The numerical calculations, however, show that the resultant well productivity is essentially independent of the perforation pattern, but is determined mainly by the total perforation density. Thus, for example, for a density of three perforations per foot of casing, the well productivity will be cut to one third of that of the uncased well for a perforation radius of 1/3 in., and to approximately one half for a perforation radius of 1/4 in,, regardless of the detailed manner in which the perforations are distributed over the casing surface. The analytical theory is also extended to include wells completed with slotted liners. It is shown that the reduction in productivity due to such liners will be relatively small as compared with that due to perforated casings.

Jan 1, 1942

By G. Howell Clevenger

PAGE Introduction,............891 L Nature of Precipitates,.........892 11. Experimental Work Upon Alloys,......895 Silver,............895 Gold,............896 Conclusions,............896 111. Present Methods of Refining,.......897 1. Refining by Roasting,.........897 2 Refining with Acid,..........898 3. Smelting with Lead,.........902 Tavener's Method,..........903 Merrill a Method,.,........903 Comparison of Costs of Acid-Refining and Smelting Processes,. . 904 Detailed Costs of Refining Cyanide Precipitates at Lead, So. Dak., September 29, 1903,.........904 Cost of Acid-Refining at the Horseshoe Mill, Terry, So. Dak.,. . 907 IV. The Removal of Zinc by Distillation,.....908 Experimental Distillations,.....,...910 Analysis of Precipitates Used for Distillation-Experiments,. . 910 Discussion of the Results of the Distillation-Experiments,. . 915 V. General Conclusions,.........917 VI. Outline of a Proposed MEthod OF Treatment,.... 917 Introduction. Attempts to discover, for the cyanide process, a better precipitant than zinc have been unsuccessful. Hydrogen sulphide, sulphurous acid, ferrous sulphate, etc., precipitate gold and silver from cyanide solutions either not all or incompletely.

Jan 1, 1904