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By R. Taggart, G. R. Purdy

DURING a study of the tempering of ß-quenched alloys of cobalt in titanium, parallel lines were observed crossing certain faces of retained-ß crystals in the early stages of tempering, Fig. 1. The lines closely resemble stress-induced martensite' or substructures attributed to clusters of faults in titanium-nickel2 and copper-silicon3 alloys. The markings were observed only in intensely etched quenched and tempered alloys having compositions ranging from 4.5 pct* Co (the composi- formed by the lines was reproduced upon repolishing and reetching. Close metallographic examination indicated that the markings were troughs, Fig. 2, and that the characteristic surface substructure persisted within the troughs. The occurrence of the troughs was associated with the age hardening reaction due to the metastable u) phase (previously reported in titanium-cobalt alloys by Raub and Beeskow4 and indicated in this work by the broadening of 0 diffraction peaks and by hardnesses approaching 600 Dph). The troughs

Jan 1, 1961

By E. C. Reed

Oil was discovered in Nebraska on Nov. I, 1939, when the Pawnee Royalty Company's Boice No. I well, about 3 miles west of Falls City (NE 1/4 NE 1/4, sec. 18, T.r N., R.16 E., Richardson County) was drilled into the Hunton formation but the develop-ment of the area took place during 1940. After a pumping test lasting 18 days, the Boice well stopped producing and failed to qualify for the State bonus of $ 15,000 offered for the first oil well to produce go bbl. per day for 60 consecutive days. On May 9, 1940, the Pawnee Royalty Company's Bucholz No. I well was completed about M mile southeast of the discovery well and flowed at the rate of about 330 bbl. per day, easily meeting the State bonus requirements. In addition to the discovery well, which later was reconditioned, and the bonus well, 28 producers were drilled in the Falls City field during 1940. Of these wells, 23 are in sec. 20, two are in the northern part 'of sec. 29, two in the southwestern part of sec. 17 and three in the eastern part of sec.

Jan 1, 1941

By Gram Curtis

The keen and close competition now ruling in the iron and steel manufacture requires imperatively, in the design and construction of the machinery employed, the fulfilment in the highest practicable degree of two cardinal conditions: economy of labor in operation, and durability. The daily pay-roll and the cost of repairs far outweigh in importance the interest on the first cost of this part of the plant. It is believed that the apparatus here described will be found to embody, in these respects, a substantial imprevement upon the present manner of handling ingots and moulds at our large steel-works. Although it includes a number of novel features, it consists essentially in the choice and grouping of certain approved economical devices specially suited to the particular service required. Fig. 1 is a plan, and Figs. 2 and 3 are elevations of parts of a Bessemer converting-house, together with a small portion of the blooming-mill—suficient to illustrate clearly the means and manner of handling the ingots and moulds. A short cable-road of simple form, somewhat similar to those used

Jan 1, 1892

By Adrian C. Dorenfeld

Concentradora "Doña Aida" (100 t /d capacity) was built in 1971-72 to treat dumps and ores containing mixed oxide-sulfide copper-gold-silver minerals derived from two veins. The veins, Don Felipe and Maria, are about 150 m apart, but are distinctly different mineralogically. The deposits are near Sun Juan de Guadalupe, Durango, Mexico. All new process equipment was manufactured locally, in or near Torreon, Coahuilu. Sampling, ore testing, flowsheet design, plant design, drawings, purchasing, financing, and construction, etc., were planned and directed by two engineers. Construction was executed by local miners and common labor (largely agricultural). The paper presents detailed costs for equipment and construction. The subsequent breaking-in operation is discussed.

Jan 1, 1982

By P. H. Thornton

MaNY intermediate phases are solid solutions which have a solute-solubility range greater than 3 at. pct. These phases, which are generally very strong and often have simple crystal structures, are usually extremely brittle so that specimens of simple shape cannot be produced by the usual mechanical-deformation techniques. Furthermore, single crystals of reasonably uniform composition are difficult to grow by the Bridgman technique because the phases generally form by a peritectic reaction, which causes pronounced segregation. In this note, a technique is described for the preparation of thin-rod specimens of brittle intermediate phases, which may be used for physical-property studies such as resistivity changes' and for the conversion of such rods into single crystals. The method has been used for the preparation of rod single crystals of the phases and Ingots, of about 100 g weight and 11 mm diam, were made by melting together the appropriate amounts of high-purity materials (usually 99.999 pct) in sealed

Jan 1, 1967

By Calvin Bjorne, John Keeley

In the face of a highly competitive iron ore market, the Cleveland-Cliffs Iron Co. developed a process now being practiced at the company's Republic mine in Michigan's Upper Peninsula. By this process, a specular hematite crude ore is being beneficiated to produce a high iron-low silica concentrate with a suitable size structure for the production of a high quality pellet. This process involves crushing, primary grinding and primary flotation, followed by regrinding, heating and refloating the primary flotation concentrate. The ores consist predominantly of specular hematite with relatively minor amounts of magnetite and martite in a recrystallized chert gangue. A wide variety of silicates have been identified, particularly in association with intrusives of various description. The more abundant of these are sericite, talc, grunerite and chlorite with some carbonates, primarily calcite.

Jan 6, 1964

By J. B. Hiskey, G. Ramadorai

This paper presents the kinetics of leaching pure wulfenite (PbMoO,) with sodium sulfide solutions. Wulfenite dissolves in the presence of sulfide ion according to the following reaction: PbMoO , + S= PbS + MOO;. Synthetic galena is formed and molybdenum is released to solution as molybdate ion. The reaction follows the shrinking core model and the leaching mechanism involves mixed kinetics where both diffusion and chemical reaction are rate controlling. Molybdenum extraction is explained in terms of temperature, particle size, and sodium sulfide concentration.

Jan 1, 1977

In the seven years that have elapsed since the AIME World Symposium on Mining and Metallurgy of Lead and Zinc, there have been a number of significant milling innovations and trends implemented in lead-zinc flowsheets to either improve grade and recovery or to control escalating mill costs. First, mill controls and instrumentation, which only had a foot in the door in 1970, have become increasingly common. In Australia, research into automatic crushing control has been implemented by Mount Isa Mines, and in virtually any large lead-zinc mill worldwide, an assortment of on-stream x-ray analyzers, grinding circuit controls, level detection devices, and reagent metering methods can be found. The increased circuit control offered to mill operators by this new technology points to more efficient flowsheets, as well as to a greater dependence upon computer-controlled operation.

Jan 11, 1977

By P. G. Coombs

The kinetics of the cyclic oxidation and reduction processes for palladium powder were examined in the temperature range 848 to 923 K. The changes in oxidation behavior due to cycling are shown to result from the decrease in surface area. Sintering is found to occur only during the reduction process. Oxidation kinetics were found to follow a cubic law with time and yield a relation for the oxidation rate constant of k x = (1.05) 106 exp P74.0). 103 / RT] The kinetics of reduction are demonstrated to be first-order with the rate constant described by the expression: kr = (7.69) 1012 exp [-(208.0) 103 / RT] . In both expressions R is in J.mo1-1.K-1.

Jan 1, 1984

By C. W. Schulties, W. J. Mallio, L. J. Petrovic, J. A. L. Campbell

Roof control comprises about 35% of direct and indirect underground mining costs. In addition, difficulties in estimating roof control costs for new areas lead to the greatest uncertainties when negotiating coal contracts. And obviously, coal cannot be mined if the roof can't be held. Accordingly, there are strong incentives to attack this problem on as many fronts as possible. One successful geological modeling technique for predicting future roof conditions was recently applied at Peabody Coal's Simco mine No. 5, located in Coshocton, Ohio. Benefits derived from it included: - A better identification of areas where poor safety conditions may be encountered. - Improved roof control cost estimates for contract negotiations. - Estimates of time-duration while mining in bad roof areas. - Labor and materials cost predictions in an existing mine. - Productivity increases through prior knowledge of areas to avoid.

Jan 10, 1975

By D. O. LIVINGTON

(Presented by invitation at a meeting of the Spokane Local Section of the institute, Feb. 17, 1912.) THE Pilares de Nacozari mine is located in Sonora, 75 miles south of Douglas, Ariz. The town of Douglas is on the International Boundary and is the place at which the ores from the Bisbee mines are smelted. The Moctezuma Copper Co. owns the mines at Nacozari, and the copper-concentrates shipped to the Copper Queen smelter, at Douglas, make a good smelting-mixture with the Bisbee ores. The Moctezuma Copper Co. and the Copper Queen smelter at Douglas, as well as the railroad from Douglas to Nacozari, are owned by the Phelps Dodge Co. The ore-deposit occurs in the form of a large ellipse with a major axis of approximately 2,000 ft. and a minor axis of about 600 ft., the major axis bearing about 90 W. of N. The whole of this ellipse is more or less mineralized; the surface being principally an iron gossan with some occasional copper-stains. Below the oxidized zone, which is not more than 50 ft. deep, the minerals are pyrite and chalcopyrite, with occasional seams of chalcocite, the latter being rare. There appears to be no well-marked zone of secondary enrichment, the oxidized gossan over the greater part of the deposit changing suddenly to what is apparently the original unaltered ore. The copper-values are concentrated around the perimeter of the ellipse, and it is principally around this perimeter that the mining is done. The ore mined averages a little more than 3 per cent. of copper, with a small amount of silver, less than an ounce per ton. Some ore of considerably higher grade than this has been shipped, however, but the above average is of the mill-run. The ore is wider near the two ends of the ellipse than along the sides, and is mined in some cases to a width exceeding 200 ft. The country-rock for the first vertical 500 ft is a volcanic acid breccia, probably rhyolitic; below

Sep 1, 1912

By Forrest W. Kinsey

The use of pellets in North American blast furnaces has made the mixes used in the associated sinter plants unique. These mixes generally contain a high percentage of fine waste oxide materials as the principal iron bearing portion of the mix, with iron ores and concentrates added in minor amounts only. Additionally, the sinter basicity is always above one and can be three or higher. This paper will discuss the large body of knowledge and experience developed by one company on this type of sinter mix. Results of laboratory tests will be used to illustrate how mix composition and feed preparation affect sinter productivity and quality.

Jan 1, 1977

By G. R. Palmer

The occurrence of mercury minerals in precious metal-bearing ores has long been noted. During cyanide leaching of these gold-silver ores, some mercury forms a soluble cyanide complex, which is present in the pregnant leach solution and passes through the process operations of the cyanidation mill. As a result, mercury is found on the electrowinning cell cathodes, on the stripped carbon before It is volatilized during carbon regeneration, or in theme tailings pond. The U.S. Department of the Interior's Bureau of Mines is examining the effectiveness of two ion-exchange resins to adsorb gold and/or mercury from a cyanide leach solution. The resins, Duolite A-7 and Ionac A-305, were contacted with leach solutions containing varying concentrations of mercury, gold, and silver. The resin A-7 reached a maximum mercury loading of 0.0165 lb Hg/ft3, and A-305 reached a maximum mercury capacity of greater than 0.44 lb Hg/ft3. Adsorption of gold by both A-7 and A-305 is influenced by the presence of additional ions in the solution.

Jan 1, 1984

By S. Chander, D. W. Fuerstenau

The inherently sluggish nature of the reactions involving sulfide minerals, particularly molybdenite, in aqueous solutions under ambient flotation conditions make their investigation complicated and difficult. Since the physicochemical nature of sulfides is known to be controlled by electrochemical reactions, a number of attempts have been made in the past to study sulfide mineral-collector interactions through rest potential and electrode polarization measurements. The purpose of the present investigation was to study the interaction of potassium diethyldithiophosphate (KDTP) with molybdenite. In the present investigation of the interaction of KDTP at the molydenite surface, molybdenite electrode rest potential measurements and electrode polarization behavior were experimentally determined under various solution conditions. The standard reduction potential for the equilibrium between dithiophosphate ions (DTP-) and bis(diethoxythiophosphoryl)disulfide (DTP) [(DTP). + 2e :i7-± 2DTP- (1)] can be evaluated from the electrode rest potential measurements on a platinum electrode in deoxygenated KDTP solutions saturated with freshly prepared (DTP)2. Experimental A platinum wire was used as the electrode for potential measurements. Prior to each measurement the elec-

Jan 1, 1975

By John P. Bingham

GRACE mine and mill, owned by Bethlehem-Cuba Iron Mines Co. and operated by Bethlehem Cornwall Corp., are being developed to produce 9600 tons of 42 ½ pct Fe magnetite ore, to yield 5760 tons per day of agglomerated iron concentrates averaging 65 pct Fe. Located about 14 miles south of Reading, the property is ideally situated in relation to good highways and railroad. Three major steel plants, at Bethlehem, Steelton, and Sparrows Point, Md., are about equidistant from the mine. Discovery of the orebody resulted from an airborne magnetometer survey, completed in 1948, con¬sisting of 7000 lineal miles of flight lines spaced one-fourth of a mile apart and extending from the Delaware River on the east to Gettysburg, Pa., on the west. After examining the magnetic maps, Bethlehem's geologists made limited surface traverses over the Grace mine and Warwick area to check the location, and realtors were engaged to purchase the desired properties over and adjacent to the area showing favorable indication of ore.

Jan 1, 1957

By Adrian E. Ross

DRILLING through caving formations in diamond drill holes at depths greater than 2000 ft has long been a serious problem. These caving formations are normally passed only by casing the hole or by cementing the hole. Casing the hole is possible only when a resulting smaller hole is acceptable. In as much as only a limited number of reductions are economically practical, cementing is frequently considered the only method suitable for solving these problems. Cementing either by pumping a slurry into the hole or by dropping cylinders containing cement has proved satisfactory on holes under 2000 ft. In holes substantially deeper than 2000 ft these methods are not satisfactory, since during the pumping process cement separates out, whereas cylinders usually break before the bottom of the hole is reached. A new procedure, the injector method, apparently solves these problems.* With this method, cement is lowered in the hole in a cylinder, the cement being

Jan 1, 1952

By A. P. Young, L. I. Marsh

HE relationship between microstructure and *- fracture is of interest in many metals and alloys. This relationship is sometimes established by examining the fracture surfaces and the flat surfaces near the fracture path in tensile samples. However, it is often difficult to tell from examining the fractured sample whether the fracture is intergranular, intra-granular, or a mixture of both. Also, it is often of interest to follow the progress of slip, twinning, or crack formation along the fracture path before fracture occurs. The ambiguity concerning the type of fracture generally can be resolved if the area along the path of ultimate fracture can be photographed at inter-

Jan 1, 1959

By J. T. Burwell

THE crystal orientation in silicon iron that has been given a particular treatment described by Goss,1 has been studied by Goss, by Bozorth2 and by Sixtus,3 but their results do not agree and are almost entirely qualita-tive. The following pages give a description of the orientation of the crystals in the material as determined by means of X-rays and expressed graphically in a pole figure. The treatment consists of hot-rolling the material into strip and then giving it two cycles of cold reduction followed by recrystallization. This produces remarkably good properties in the rolling direction, the product having a maximum permeability in this direction of more than 25,000 and a permeability at 16,000 Gauss of more than 2200, It is now generally agreed that Goss's original conclusion' that the crystals in the final product are randomly oriented was incorrect, since Bozorth2 and Sixtus,3 using different methods, have shown that there is a decided preference in orientation. Those writers, however, expressed their results only in terms of one or more ideal orientations with deviations therefrom.

Jan 1, 1940

By Fred D. DeVaney

MINNESOTA taconites are extremely hard, and fine grinding is required to produce an acceptable concentrate. To reduce grinding costs, waste material is rejected by magnetic separators as soon as it is liberated. Cyclones are now used in all Minnesota taconite plants to close the grinding circuits. Erie Mining Co. installed its first grinding section at Aurora, Minn., in 1948-a 9 ½ x12-ft. mill and a fine grinding section consisting of a 10 ½ x12-ft ball mill in closed circuit with a duplex 60-in. spiral classifier. Concentrates from the magnetic cobbers treating the rod mill discharge passed directly into the classifier; the ball mill discharge was also treated in magnetic separators and the concentrate from these machines also went to the spiral classifier. Both concentrates passed through ac demagnetizing coils. It is axiomatic that for proper classification the material in suspension must be well dispersed, and it follows that magnetic concentrate must be almost completely depolarized if classification is to be successful.

Jan 8, 1957

By Plato Malozemoff

Our young, technically oriented people today are entranced by the space program, by physics that unlocks the secrets of nature, by electronics, and by other new technologies. The mining industry seems to be their last choice. Enrollment in mining schools is dropping and so is the interest of our great universities in mining curricula. The image of the mining industry appears to be one of being conservative, nonprogressive, resistant to change, and lacking in excitement and challenge. I submit that this public image is wrong. While the initial development of mines is usually slow and seemingly plodding, the problem of solving the imponderables of nature-the ore emplacement, its structure and physical characteristics, its response to recovery processes, and its probable ultimate profitability-is stimulating to the most acute and searching of minds and requires careful application of a combination of many technologies. The paths to obtaining the desired results must be within the bounds of reasonable expenditures in the early stage of development when risks are still high, and this financial discipline is a further stimulus to the imaginative search for the right answers.

Jan 6, 1968