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By Gabriel Plascencia

Copper was oxidized in the temperature range from 300 to 1000 GC under different pressures of oxygen. In the range from 300 to 500°C, copper oxidizes following the logarithmic rate law; while in the range from 600 to 1000°C oxidation follows the parabolic rate law. Transition from logarithmic to parabolic growth occurs at about 525°C. X-ray diffraction was performed on oxide scales to account for the CuO/Cu2O ratio at different temperatures. Activation energies found in this work are in good agreement with reported values.

Jan 1, 2003

By F. D. Weeks

THE Salida smelting plant, owned by the Ohio & Colorado Smelting & Refining Co., is situated at an altitude of 7,000 ft., about 2 miles west of Salida, Colo., and 215 miles southwest of Denver. Salida is a division point on the. Denver & Rio Grande R. R. where the narrow-gauge line serving the Sari Juan region joins the through standard gauge. This narrow-gauge road also serves the coal and coke companies at Crested Butte and the lime quarries and mines at Monarch and Garfield, which are only 20 miles distant. These facts, together with the possibility of an appropriate site, doubtless influenced the builders to locate at this point. The smelting plant and yard occupy 80 acres of land on the northeast side of the Arkansas River. The slope of the ground is such as to permit of the ore being delivered by cars at a point 25 ft. above the feed floor; and in front of the furnaces there is a fall of 50 ft. for the slag clump. A recent purchase of river bottom has provided slag room for 20 years. As originally constructed, the plant consisted of four blast furnaces, 40 by 144 in. at tuyeres, two copper-matting furnaces, dust chamber, stack, power plant, blowers, sampling works, and one railroad trestle about 16 ft. from bed floor to rails. Later 12 hand roasters of excellent design were added and the practice of smelting leady matte in-a copper-matting furnace was abandoned. Since the plant passed under the present management the equipment has been increased so that the following is a brief description of the same at this date: Two lead blast. furnaces, 48 by 180 in. at tuyeres, 17 ft. 6 in. tuyères to feed floor; four lead blast furnaces, 40 by 144 in. at tuyères, 17 ft. 6 in. tuyères to feed floor; two copper-matting furnaces, not used; blast-furnace flue, 900 ft.; area 245 sq. ft.; blast-furnace stack, 150 ft.; above furnace floor, 190 ft. When smelting a 500-ton charge per day, the gases approximate 63,700 cu. ft. per minute and travel at a speed of 260 ft. per minute.

Jan 8, 1915

By Alan H. Goode

Of the 15 million tons of glass discarded in municipal wastes annually, about 2 million tons pass through incinerators and can be recovered by ore processing techniques. Although the primary use for this recovered waste glass would be as cullet in the manufacture of new glass containers, this approach is not always practical because of long shipping distances, high freight costs, and high purity requirements. Alternatives to the use of waste glass as cullet would be either as landfill or in secondary products. Although glass is considered a good landfill material, it is still wasteful of potentially valuable raw materials. Secondary products that can be made from waste glass1 include a variety of industrial and construction items. As part of the Bureau of Mines' program in secondary materials recovery, the Tuscaloosa Metallurgy Research Laboratory has conducted research concerned with the development of ceramic building products from waste glass. Materials employed in this research were obtained from municipal incinerator residues fractionated in the Bureau's continuous residue processing plant, College Park Metallurgy Research center.' The studies reported herein3,4 present research results using waste glass in the formulation and production of clay bricks, not only to produce improved products, but to reduce production costs, conserve natural raw materials, and most important, to reduce manufacturing energy requirements.

Jan 1, 1974

By T. F. Witherbee

The Iron Mountain, situated three-quarters of a mile NE. of the limits of the City of Durango, rises abruptly from a level plain, and trends N. 83' E. Fig. 1 gives a view of the mountain, with the company's iron-works. There are indications that the vein or deposit of iron-ore extends also about two leagues across the Murca ranch, in the same general direction. The Iron Mountain proper is divided into two great lenses by a horse of cantera or eruptive rock, some hundreds of feet in width.

Jan 1, 1902

The Regional Development Council has initiated a project that aims to find better ways for further investment by extractive industry companies in sustainable regional and community futures. It will be undertaken through collaborative actions that bring together the resources of private and public sector stakeholders in regional Western Australia.   The broad objectives of the project are to: describe and analyse the current situation with respect to the impediments to regional communities being more self sustaining, assess the effectiveness of the current and possible future levels of investment by extractive industry companies in the sustainable development of communities in regional Western Australia, identify and demonstrate collaborative ways in which extractive industry companies in Australia and other countries can play an enhanced role in sustainable regional and community sustainability through strategic engagement and investment; and confirm the effectiveness of the collaborative measures in delivering sustainable outcomes for regional communities by way of attracting and retaining populations and enterprises in Australia and similar environments.

Jun 1, 2010

[YEAR OF ELECTION 1913. FRANK DAWSON ADAMS Montreal, Canada 1938. HENRY CORT HAROLD CARPENTER London, England 1933. KARL EILERS New York, N. Y. 1922. FEDERICO GIOLITTI Torino, Italy 1906. SIR ROBERT A. HADFIELD London, England 1921. FRANK WILLIAM HARBORD London, England 1917. HERBERT HOOVER York, N. Y. 1939. HENRY KRUMB New York, N.' Y. 1921. C. McDERMID London, England 1913. EZEQUIEL ORDONEZ Mexico City, Mexico 1935. ROBERT PEELE New York, N. Y. 1938. A. M. PORTEVIN Paris, France 1937. JOHN V. W. REYNDERS New York, N. Y. 1937. GEORGE S. RICE Washington, D. C. 1911. ROBERT H. RICHARDS Cambridge, Mass. 1934. T. A. RICKARD Victoria, B.C., Canada]

Jan 1, 1940

By Hiroshi Ono

"By newly developed ICP method, trace amounts of As(III), As(V) .,Sb(III) and Sb(V) were precisely determined within accuracy of sub ng/ml. As(III) and Sb(III) were separated from As(V) and Sb(V) by extracting into ·xylene as diethyldithiocarbamate complexes using diethylammonium diethyldithiocarbamate (DDDC), and then back-extracted into nitric acid for a quantitative determiruition by ICP-AES equipped with hydridegeneration system The recoveries of As(III) and Sb(III) were satisfactory throughout the extraction with 0.04mol/l DDDC in xylene from lmol/l hydrochloric acid solution and the back-extraction with 7 mol/l nitric acid. As(V) and Sb(V) were reduced to As(III) and Sb(III) by ascorbic acid and potassium iodide, and their quantities were determined as mentioned above. The detection limits were found to be 0.58ng/ml for As(III), 0.63ng/ml for Sb(III) using 50ml of a sample. The proposed method was applied to analysis of the real sample.Introduction In drain, arsenic(AS) concentration is prescribed below 0.lmg/l, so As must be removed. As is existed at .the form of As(III) or As(V) in solution. For t1Jeir difference of chemic;µ property, it is not easy to remove As in solution. So it is an urgent necessity to develop for determining concentration of As(III) and As(V). Antimony( Sb) has resemblance .chemical property to As. So Sb was experimented the same as As.The separation and determination of As(III) and As(V) have been carried out using several methods, such as ICP after copreclpitating separation, HPLC, direct hydride generation atomic absorption. However these methods have some problems. One of main problems is that HPLC and direct hydride generation atomic absorption methods are influenced by coexisting elements."

Jan 1, 2000

By Edwin A. Rides

HISTORICAL ORIGIN OF THE EXPORT CREDIT AGENCIES Almost since the inception of international commerce sellers, having manufactured and/or sold and shipped goods to an overseas buyer, have been obliged to accept the risk that they will not be paid for one reason or another. There are many reasons why payment may not be forthcoming, for example, the goods may be lost at sea, or rejected by the buyer or the buyer nay simply not be creditworthy. These risks were brought into sharp relief as international trading became more sophisticated and the practice of giving credit to buyers gathered momentum. Inevitably enterprises sprang up which offered same mitigation of this exposure, accepting houses and later confirming houses and banks were prepared to assure acceptable credit risks an behalf of the seller, usually by discounting trade paper, and for many years the market ticked over reasonably satisfactorily. However, after the 1914-18 War international trade was at an extremely low ebb and its inherent risks were accentuated to a point where they were often commercially unacceptable. Yet a healthy and vigorous international market was indispensable to recovery of the world economy and a number of governments, led by the United Kingdom, perceived a need to offer their exporters a comprehensive form of insurance, particularly to facilitate the extension of credit to foreign buyers. In the United Kingdom the Export Credits Guarantee Department (ECGD) was set up to encourage trade through the provision of export credit insurance. Over the ensuing years others followed suit and now most of the developed trading nations and many developing nations have similar agencies. PRESENT DAY IDLE OF THE EXPORT CREDIT AGENCIES (ECAS ) Traditionally then the BA's role was to encourage trade through the provision to exporters of insurance against the risks of non-payment by overseas buyers of their goods and services. However, during the 1970's the manufacturing industries of most of the developed nations found themselves facing severe competition for business, particularly in the developing world. As a result the more aggressive ECA's began to introduce ancillary forms of cover designed to reduce exporters' risks outside of the credit field. For instance, most of the European agencies now have a form of cover against foreign exchange risks here contracts are denominated in currencies other than that of the exporter's country. Most of the agencies also provide cover to exporters against the risk of unfair calling of bid, advance payment, performance bonds etc and in certain countries, where high inflation rates were endemic, a form of cover against cost escalation. In certain circumstances it is also possible for an exporter to obtain cover against losses arising as a result of the involvency of a partner in a consortium or joint venture. These are all forms of insurance but, also during the 1970's, many of the national export credit programmes took a major step away from their original raison d'etre by facilitating the provision of preferential financing terns for the acquisition of capital equipment by an overseas buyer. This new line of business quickly became an important ingredient of major export financing packages and, as we shall see later, turned out to be extremely costly for the countries providing it.

Jan 1, 1985

By F. W. Bloecher

D ETERMINATION of the surface area of finely divided minerals is of interest to mineral engineers engaged in flotation, comminution, and dewatering studies. In the industrial minerals field, many materials are classified as to fineness according to their specific surface (surface area per unit weight). A method of surface area determination has been tested and used in the Richards Mineral Engineering Laboratories at M.I.T. It involves low temperature krypton adsorption measurements using the technique described by Beebe.1

Jan 3, 1951

By G. A. Smyres

The Bureau of Mines conducted laboratory studies to determine the feasibility of chlorine-oxygen leaching for treating low-grade zinc sul-fide flotation concentrates. Recovery of zinc sulfides by flotation from complex fine-grained sulfide ores is substantially higher in low-grade bulk sulfide concentrates than in the high-grade cleaned concen-trates required for smelter feed. However, there is no commercial process in the United States for the treatment of low-grade bulk zinc sul-fide concentrates. Leaching experiments using reactors of 500-mL and I-gal capacity were conducted on a bulk concentrate containing 19.3 pct Zn, 35.6 pct Fe, and 39.4 pct S. The effects of pressure, temperature, and percent solids on extraction were investigated. The chlorine-oxygen leaching procedure showed promise for treating the concentrates. Zinc extractions of 95 pct or more were obtained by leaching at 50 pct solids in the temperature range of 1000 to 1200 C. Zinc extractions by leaching with chlorine followed by oxygen at reactor pressures of 50 to 100 psig were independent of pressure.

Jan 1, 1985

The extinction of zinc from steelmaking dusts has been studied with a laboratory scale reduction-vapour deposition (RVD) process in the absolute pressure and temperature ranges of 13 - 1300 Pa and 1333 - 1513 K respectively. This process consists of pre-reduction of iron oxide by carbonaceous agent, carbothermic reduction of zinc oxide under reduced pressure to produce zinc deposits and subsequent re-evaporation of the deposits to liquedify the zinc. In the RVD, the gas mixture of Zn and CO quenched from the hot zone is separated into Zn deposit and CO which is transferred to the pumping system. The Zn are a layer of fine metallic zinc powders accumulated on the cold wall and removed to the vacuum distillation chamber. The experimental works have been carried out according to the following items: carbothennic reduction of zinc oxide under vacuum, carbothermic reduction o zinc ferrite under vacuum, and 3. distillation of the Zn deposits. It has been concluded from these experimental results that the recovery of metallic zinc from the EAF dusts is successful by this process, and a new concept for a practical zinc winning process has been proposed.

Jan 1, 1993

A. M. CANDY,* Pittsburgh, Pa.-I think more stress should be laid upon the question of welding with the carbon electrode, which we ordinarily call graphite arc welding. Mr. Miller's photograph indicated that the original parent metal had been decarburized to a marked degree. It would be interesting to know the carbon content of the parent metal, and whether or not Mr. Miller has made any investigations to determine if the metal is always decarburized or whether in some instances we actually have carbon injected into the weld, which has been the understanding that has been quite prevalent. There were one or two other points that Mr. Miller brought out concerning which I desire to ask one or two questions: The illustrations that he presented were obtained with what, I suppose, would be termed a real low-carbon steel welding wire, which gives in the deposited metal grains that are more or less symmetrical, whereas the Roebling electrode, which is a mild steel of higher carbon content, apparently gives a columnar structure. I do not know which-of these I structures is more desirable, but assuming that the structure produced by the really low-carbon steel wire is the more desirable, would it not be true that the very low carbon content would, probably owing to high temperatures that prevail in the arc, result in a greater amount of oxidation and probably result in either carrying into the weld more oxide or producing more oxide on the surface as the operator progresses? The short arc is an advantage in all cases. Whether Mr. Miller's trouble is oxide or nitride, the short arc helps him out, because the closer the end of the electrode is to the work the less chance there is for either oxygen or nitrogen to get in. And whichever is the cause of the trouble, the short arc keeps it out by lessening the time in which the steel is molten and the amount of air that gets in. It also makes sure that the molten metal will not fall into the crater. Everything is in favor of the short arc.

Jan 4, 1919

By John K. Wright

The segregation process involves heating oxide-type ores with a halide salt in the presence of a solid reductant. By a complex series of cyclic vapour-phase reactions, the desired metal is extracted from its original position in the ore and segregated to the vicinity of the reductant. In this form it is then amenable to concentration by physical methods. In this work the segregation behaviour or eight different nickel laterite ores has been examined using a laboratory rotary kiln. It was found that the silicate (serpentine) ores responded better to the segregation conditions used than did the limonitic ores. An examination of the segregated metal particles showed that they consisted of ferro-nickel. The concentration of nickel in the metallics was sensitive to the ore types and the segregation roasting conditions.

Jan 1, 1994

By J. J. Forbes

Investigations by the Bureau of Mines and by mining-research departments of European countries have established definitely the value of rock-dusting to prevent or limit the propagation of coal-mine explosions. Its effectiveness in this connection has been demonstrated not only by research but by actual coal-mine explosions in which hundreds of lives have been saved because of its presence. In a general way this paper gives pertinent facts concerning rock-dusting practices in the United States. Information has been obtained from many reliable sources, and various coal-mining companies have furnished data on cost and other details.

Jan 1, 1939

By George M. Fowler

THE Tri-State district, as outlined in this paper, refers to the entire mineralized area in southwestern Missouri, southeastern Kansas and northeastern Oklahoma (Fig. 1). The part of the district in Missouri and near Galena, Kans., is still sometimes referred to as the Joplin district (Fig. 2). The Picher-Miami area is that part of the Tri-State district located contiguously in Kansas and Oklahoma in the vicinity of Baxter Springs, Picher and Miami. This paper is confined almost wholly to the ore deposits of the Tri-State district and particularly to the Picher-Miami area. Our study of the ore deposits of this district dates from late in 1925 (by Fowler) and early in 1927 (by Lyden) to the present. Our work has been confined almost entirely to the search for ore for numerous companies and individuals. It was not possible for us to undertake numerous highly interesting investigations which presented themselves but which would not immediately help in finding ore. We particularly refer to the general structural geology of the Ozark uplift, the genesis of the ore, and other problems of a similar nature. The local and general structural problems of the district are being solved gradually as the work progresses. The factors that control the loci of the several orebodies are evident. This paper is based almost exclusively upon our own observations. Most of the important mines in the Picher-Miami area were studied in detail. A map (Fig. 5) is included which shows this area and the properties we have examined to date. When it was convenient we visited, studied and compared structural relations in numerous mines in states outside the district. Some of these observations are noted in this paper.

Jan 1, 1932

By D. A. Sutch

En 1958 se instalaron dos hornos Tysland-Hole en la planta Siderúrgica de Chimbote, construído por Elektrokmisk A.S, cuya sede social se encuentra en Oslo, Noruega. En ese sentido, el presente texto describe el funcionamiento de dichas hornos para la reducción de minerales de fierro en Chimbote. Para el revestimiento del horno se emplean materiales aislantes diversos y tres tipos de mezclas refractarias que se colocan mediante apisonado. Asimismo, estas mezclas retractarias son apisonadas contra moldes metálicos que permanecen "insitu", es decir, que reciben la primera carga del horno.

Sep 1, 1963

By Rudolf Fahn

Bentonites are best suited for the preparation of acid activated clays with efficient adsorption properties. They are weathering products of acid volcanic ashes and their natural deposits are world-wide spread. The main constituent of bentonite is the aluminium hydrosilicate nontmorillonite with a high ability to swell. Süd-Chemie owns bentonite deposits in Germany and subsidiaries in Italy, Mexico and Arizona.

Jan 1, 1979

By F. A. G. M. Camisani-Calzolari

The uranium production forecasting program described in this paper projects production from Reasonably Assured, Estimated Additional and Speculative Resources in the cost categories of less than $130/kg U. Originally designed to handle South African production, it has been expanded and redimensioned using available published information to forecast production for countries of the Western World. The program forecasts production from up to 400 plants over a period of fifty years and has built-in production models derived from documented historical data of the more important uranium provinces. It is particularly suitable to assess production cavabilities on a national and global scale where variations in outputs for the individual plants tend to even out. The program is aimed at putting the uranium potential of any one country into a realistic perspective, and it could thus be useful for planning purposes and marketing strategies.

Jan 1, 1987

By Philippe Charlier

Recycling of aluminium contained in used aseptic beverage cartons is a difficult task which has nevertheless to be tackled by our modern societies. Techniques have earlier been developed by the paper and pulp industry for the recycling of the board fibres from collected post-consumer beverage cartons. A joint technical feasibility study by Granges and a leading beverage carton producer has dealt with different techniques for handling residues from repulping facilities. The aluminium obtained can be used as raw material for the production of thin gauge foil, thus closing the recycling loop.

Jan 1, 1995

By Hani Mitri

Understanding the interaction between rock bolts and underground rock movement is critical for safe and cost effective underground excavation design. Although early research on this subject involved a balance of theoretical analysis and field measurement, recent work has been heavily focused on analytical and numerical studies. This paper describes technologies that have the potential to redress the balance through instrumentation of rock bolts deployed under routine operating conditions in underground mines. Two new products are presented in this paper. Firstly the U-cell coupler is a load cell device that can be routinely coupled to the threaded end of a bolt prior to installation. It measures the ?series? load at the head of the bolt. Secondly, the d-REBAR involves an array of small-diameter, long-base length displacement sensors recessed into grooves along the entire length of the bolt. Both new instruments are interfaced with on-board digital signal conditioning and telemetry. Methodologies for the deployment of the new instrumentation and guidelines are presented for the interpretation of results based on data obtained from field trials. Successful field installations demonstrate the viability and practicality of these new technologies and, moreover, provide important insight in to rock bolt/rock mass interaction.

Jan 1, 2012