Search Documents

By H.A. Bedworth

AlloTs of copper and silicon have been known for one hundred years or more but the commercial development of this type of alloy has taken place during the past few years. In 1905, Sperry l proposed the use of copper-silicon alloys for springs and other purposes for which copper-tin bronzes were used. Some attention was given to this proposal at the time but no one succeeded in producing a practical alloy containing more than a fraction of a per cent. of silicon. The equilibrium relations of the copper-silicon system were studied first by Rudolfi2 and later by Sanfourche 3 and Corson. 4 The constitution of the system has also been recently investigated by Matuyama, 5 and in the laboratories of the American Brass Co. by Smith. 6 Some of the physical properties of the copper-silicon alloys have been investigated by Norbury7 and by Geiss and Van Liempt.8 Summarizing the results of various investigators of the constitution of copper-silicon alloys, the solubility reaches its maximium value, 6.7 per cent. silicon, between 721" and '782" C. At 852" (1. the solubility is 5.25 per cent., while at 400" C. it is only 4.1 per cent. silicon. The copper-silicon alloy begins to get so hard at about 3 per cent, silicon that it is difficult to manage. It was found by Jacobs that the addition of manganese to this alloy considerably improved the working

Jan 1, 1929

By H. A. Bedworth

AlloTs of copper and silicon have been known for one hundred years or more but the commercial development of this type of alloy has taken place during the past few years. In 1905, Sperry l proposed the use of copper-silicon alloys for springs and other purposes for which copper-tin bronzes were used. Some attention was given to this proposal at the time but no one succeeded in producing a practical alloy containing more than a fraction of a per cent. of silicon. The equilibrium relations of the copper-silicon system were studied first by Rudolfi2 and later by Sanfourche 3 and Corson. 4 The constitution of the system has also been recently investigated by Matuyama, 5 and in the laboratories of the American Brass Co. by Smith. 6 Some of the physical properties of the copper-silicon alloys have been investigated by Norbury7 and by Geiss and Van Liempt.8 Summarizing the results of various investigators of the constitution of copper-silicon alloys, the solubility reaches its maximium value, 6.7 per cent. silicon, between 721" and '782" C. At 852" (1. the solubility is 5.25 per cent., while at 400" C. it is only 4.1 per cent. silicon. The copper-silicon alloy begins to get so hard at about 3 per cent, silicon that it is difficult to manage. It was found by Jacobs that the addition of manganese to this alloy considerably improved the working

Jan 1, 1929

By J Fraser, M Scoble

Within the past decade, incidents of mining–community conflicts have grown dramatically and represent one aspect of a phenomenon known as social risk. Research published in 2014 indicates that a lack of social acceptance is now a leading and costly cause of delays for mining projects.The rise of social risk, complemented by the need to earn the trust of an increasing number of stakeholders so that mining projects can be developed effectively, is problematic for the industry. Conflicts are occurring in situations where companies are fully compliant with regulatory and legal requirements, despite initiatives by mining companies to earn social acceptance and despite the proliferation of tools to support corporate social responsibility. Intensifying the impact of social risk is the fact that it has increased during a time in the global mining sector when companies have had to grapple with declining commodity prices, increasing capital costs and debt levels and the challenges of mining lower-grade deposits.This paper will explore a hypothesis that in today’s interconnected society, social risk in the mining sector constitutes a legitimate business risk that must be managed strategically. The reality facing mining companies is that information, once considered confidential, now travels quickly on social networks and via a growing number of groups and individuals that have earned a legitimate right to be classified as stakeholders in projects that affect their communities. To be successful, it is suggested that companies will benefit from increasing internal collaboration and providing training to equip teams to mitigate social risk to mining projects and protect reputation capital. The paper is based upon PhD research being undertaken to assess the points of intersection between social risk and social responsibility during the construction stage of greenfield mining projects.CITATION:Fraser, J and Scoble, M, 2015. Mining–community conflicts – can the future mining sector transform social responsibility?, in Proceedings Third International Future Mining Conference, pp 159–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By C Moorhead

The classification of Mineral Resource estimates for reporting in accordance with the JORC Code is a statement of the Competent PersonÆs confidence in the estimate and an attempt to convey that confidence to the various users of the resource estimate. In general the classification process is either largely subjective, relying on the Competent PersonÆs experience, or relies on statistical measures derived from the estimation process. These statistical measures may not necessarily relate to the overall confidence in the resource which must also take account of the confidence in the geological inputs to the estimation. Several authors, including Jackson et al (2003) and Dominy, Noppe and Annels (2004), have addressed methods of including consideration of geological data and its reliability into the classification process. Henry and Parker (2005) have discussed a quantitative measure for classification of Measured and Indicated Resources related to mine production parcels. These methods rely on the availability of sufficient information for the application of geostatistics, data evaluation techniques or repeated interpretation of data to provide an indication of confidence. They are suitable for very advanced projects. In 2005, using a modification of the financial audit æcontrol and quality criteriaÆ principles, then widely accepted within Newcrest Mining Limited (Newcrest), the principal author developed a scheme which categorised the classified resources into æcontrolÆ and æqualityÆ (or risk) categories. Control covers all aspects of the data collection, the geological interpretation, the data analysis and the modelling of tonnage and grade; it is also influenced by the documentation of the estimate. The quality criteria are a subjective measure of risk associated with the estimation of the resource and refer to the risk that the tonnage and grade are not realised and the consequences if decisions are made on the basis of these estimates. By evaluating the generally accepted level of risk attributed to these quality ratings by Competent Persons within Newcrest, a graphical representation of the confidence in the resource ounces was prepared for communication of the expected confidence in the resource statement.

Jan 1, 2009

By B. K. Shibler, W. G. Sandell, G. M. Potter, H. D. Snedden

"INTRODUCTION During the course of the investigation of the occurrence of manganese deposits in the western United States, examining 'engineers of the Bureau of Mines collected samples from seven manganese properties in Grand and beery Counties, Utah. These were supplemented by five samples submitted by property owners. Since all of the ores were too low-grade for use in producing ferromanganese for steel manufacture, some means of beneficiation was required to produce marketable concentrates, and metallurgical studies were made on each of the samples.Most of the ores Investigated are similar in one respect: At least part of the 'manganese oxide areas contains minute inclusions of gangue. This occurrence materially enhances the complexity of the ore, partly by .increasing the complexity of mineral association, but largely through making manganese-quartz liberation more difficult. In such ores, there is a marked tendency for the manganese minerals to be retained as shells or coatings on the surfaces of quartz particles when crushed. Particles of this type represent considerable loss of manganese in tailing, if gravity-concentration methods are employed, or tend to' float, thus carrying an appreciable quantity of gangue into the concentrate, if treated by flotation.Plus 48-percent manganese sinters were made from some of the ores tested, but, in general, intimate association of manganese minerals with silica limited the degree of beneficiation attainable."

Dec 1, 1947

By Mark I. Copeland

A study was conducted to determine if commonly used alloying additions or coating materials can prevent the formation of a liquid-copper phase during the reheating of copper-containing steels. If so, the tendency of such steels to surface-crack during hot-working might be eliminated. Steel specimens were scaled by heating them either isothermally or in a programed manner that simulated industrial furnace practice. Metallographic examination of the heated specimens showed that molten fayalite (Fe2Si04) completely prevented the formation of liquid copper at the surface. Fayalite, which melts at 2,200° F (1,205° C), was formed by internal oxidation of the silicon contained in the steel. By forming complex molten oxides, coatings of borax glass were also effective in preventing the occurrence of liquid copper at the steel surface.

Jan 1, 1972

By Takahiro Kubo, Katsunori Yamaguchi, Hidehiro Sekimoto

Equilibrium relation between B2O3 slag, RExOy-B2O3 (RE = rare earths) slag and Fe-C alloy formed by melting treatment of neodymium magnet and B2O3 was investigated. When neodymium magnet was melted together with B2O3 and Fe-C alloy in carbon crucible, 3 liquid phases of B2O3 slag, RExOy-B2O3 slag and molten Fe-C alloy formed and clearly separated by the difference of the specific gravities. In the case that excess amount of Cu was also introduced in that system, molten Cu phase additionally formed. Almost all amount of RE were concentrated in RExOy-B2O3 slag. The concentration of RE in RExOy-B2O3 slag increased with the decrease of the melting temperature. While chromium, phosphorous, nickel, cobalt, and copper were concentrated in molten Fe-C alloy, silicon and aluminum were distributed in B2O3 slag and RE2O3-B2O3 slag.

Jan 1, 2014

By P. Burmeister, R. A. Errath, A. Sapin

Sag Mills are becoming bigger in size almost every year. Concentrator plants are also becoming larger with more SAG and Ball Mills units with Gearless Mill drives installed in one plant. In contradiction to this development, concentrator plants are being built in increasingly remote areas, where the power supply and network conditions are not necessarily covering the needs for the operation of such plants. This paper describes sources of harmonic distortions and possible approaches to solve this problem. It also illustrates the permissible tolerances in terms of commutation of power electronics, based on already realized installations. Furthermore it explains how, and with which measures, harmonic currents created by non-linear loads with SAG and Ball Mill drives can be handled, and how harmonic standards can be fulfilled accordingly. Finally, this paper gives an overview about the technical impact of a strong versus weak network, and the economic relationship between them.

Jan 1, 2001

By F. S. Kendorski

This report presents the results of a search for viable-self-drilling roof bolt concepts, detailed development, design, and manufacture of such bolts that drill their own holes, and testing in the laboratory and in the field in two different coal mines of three self-drilling roof bolts. Three new types of bolts were designed and tested, which drill their own holes and then anchor in continuous operation. These were a spring-actuated mechanical expansion shell, a slot and wedge, and a self-contained resin anchor bolt. Such bolts when fully developed for mine use would allow safer and remote installation of ground support and increase productivity. Recommendations are given for further work to improve drilling and anchorage performance.

Jan 1, 1979

By Madan Kumar Annam, Hari Krishna Y

"Basement construction is one of the challenging geotechnical concerns in the urban environment. Several types of retention systems are practiced to support the earth which is suitable for restricted access, rapid mobilization, fast excavation and cost-effective designs. A thorough understanding of geotechnical engineering as well as the structural mechanics is important for the earth retention systems. This paper discusses a project with various types of foundation solutions including monitoring of deflections during excavation stage of a retention system.A multi storeyed residential building (3B+Stilt+18F) in Chennai having structure foot print area of 1500 m2 has to be constructed on large diameter pile foundations and also to support the proposed basement excavation. Ground water table was encountered at about 6m below the existing ground level (EGL). In order to support heavy structural loads, large diameter bored cast-in-situ piles were chosen and installed. Further, complete retention system was economically designed and built, which includes installation of Contiguous Bored Piles (CBP) in combination of vertical grout columns behind CBP wall to seal the gap between the CB Piles, installation of inclined ground anchors, construction of capping beam, stressing and locking of installed ground anchors. A detailed monitoring program was in place and continuous monitoring of wall deflections is being measured at the time of publishing this paper. This paper describes the design and construction aspects adopted for foundation and retention system including the monitoring results during excavation stage of the project.INTRODUCTIONIn general, stage wise open excavation will be opted for basement construction where plenty of space is available. Due to urbanization and restricted space, open excavation became a difficult task nowadays. To overcome this problem, suitable retention system need to be selected to retain the soil mass. Selection of suitable retention system for multi-level basement excavation is a great challenge in geotechnical industry, especially when the proposed site is located within the minimum set back distance from the existing structures. This in turn calls for the advanced and innovative methods of retention system.Several earth retention systems such as Diaphragm Walls, Secant Pile Walls, CBP system, Soldier Pile Walls, Sheet Piles, Deep Soil Mixing (block walls) etc. with or without inclined ground anchors are being practiced worldwide. Considering the advantages and disadvantages of the available retention systems in practice locally and keeping in view of present site conditions, the developer has chosen CBP system with inclined ground anchors so that all foundation related works of the project will be handled in a single package. The main advantage of such packaged solution will ease the coordination between design consultants and foundation contractor resulting in faster construction of foundation works which in turn reflect savings in time and cost."

Jan 1, 2015

By F. J. Tavera, J. A. Finch

A probe suitable for on-line measurements of gas hold-up in industrial flotation systems has been developed. It is based on an open cell for measurement of slurry-gas conductivity and a novel syphon cell for measurement of slurry-only conductivity. The desired behaviour of the two cells was demonstrated and estimates of gas hold-up were shown to be in good agreement with independent measurements. The gas hold-up probe was used as a diagnostic tool to assess the operation of flotation columns. Differences in gas hold-up between baffled sections in two industrial columns were detected

Jun 18, 1905

By Lukasz Maciag, Ryszard Andrzej Kotlinski, Ryszard Krzysztof Borówka, Dominik Zawadzki

Concentration and composition of rare earth elements (REE) and major elements in the sediment samples from the IOM H11 Fe-Mn nodule deposit, eastern part of the Clarion-Clipperton nodule field (located between the Clarion-Clipperton Fracture Zone - CCFZ; tropical Pacific), have been studied. We show the controls on REE concentrations and described vertical/horizontal variability of selected metals in pelagic sediments from the CCFZ. According to Kato et al. (2011), who analyzed 2000 seafloor sediment samples at 78 sites of the Pacific Ocean, deep-sea mud shows high concentrations (2230 ppm maximum) of ?REY and could be potential resource of these elements in the future. However, our work does not fully confirm that sediments in the IOM H11 are significantly enriched in REE.

Sep 1, 2014

By Richard L. Rains

The Bureau of Mines made a study of mines and prospects of the Benton Range RARE II area (No. 5056), Mono County, California in October and November 1980. The study area is west of Owens Valley and 30 mi (40 km) north of Bishop, California. The mineral deposits were evaluated by examination of mines, prospects, and mining claims by the Bureau of Mines. Geological, geochemical, and geophysical studies were conducted by the Geological Survey. The principal mineral commodities of the Benton Range RARE II area are gold and silver but tungsten deposits may also extend into the area. Properties with resources are listed in table 1; their locations are shown on figure 1.

Jan 1, 1982

R. W. Raymond, New York, N. Y,:—Since the presentation of my note on this subject at the New York Meeting, Professor Louis has pointed out an error in my statement of his conception of " pitch "—namely, he understands the pitch, in the restricted sense which he proposes, to be the angle of inclination of the axis of an ore-body, measured on the vertical plane drawn through the body; whereas, I represented him as proposing to define " pitch " as the angle of inclination of an oblique body, measured on the plane of the dip, in the direction of the strike. The difference will appear upon consideration of the accompanying isometric projection, Fig. 1, in which ABCD represents the plane of the inclosing ore-deposit (vein or bed), and AC the axis of the oblique ore-shoot. ABE is the angle of the dip, as universally understood; and ACE

Jan 1, 1909

By Annie G. Smelley

As part of its program to develop technology that will encourage maximum utilization of the Nation's mineral resources, the Bureau of Mines conducted research on debrining potash-clay waste slurries by means of flocculation with a high-molecular-weight polymer and subsequent solid-liquid separation on a rotating trommel screen. In laboratory batch tests, potash-clay waste slurries were consolidated from initial clay contents of 8 pct to final contents of 30 pct with a polymer dosage of 1.2 Ib/ton of dry clay waste. Small-scale continuous tests yielded debrined products containing 20 pct solids using a polymer dosage of 1 Ib/ton of dry clay solids.

Jan 1, 1983

Roles of Mineral Impurities and Sulfur in the Leaching Behaviour of Pre-Reduced Ilmenite Ores

Sep 13, 2010

By EDGAR K. SOPER, Clarence A. Wright, DOUGLAS C. LIVINGSTON, Thomas Varley

In 1917 the Federal Bureau of Mines and the University of Idaho arranged to cooperate in an investigation looking to the improvement of mining and milling methods in the mining districts of the State of Idaho, with an especial view to the wider development of the minerul deposits and greater efficiency in the treatment of the lowgrade ores of the State. This work has been made possible lnrgely through the generosity and active assistance of the mine operators, especially certain companies in the Coeur d'Alene region. As the first step in the work under the cooperative agreement it wa.s decided to gather all data possible on the various mining districts throughout the State, both active and abandoned, in order to ascertain their potential possibilities, especial attention being paid to methods of metallurgical treatment and to the solution of the many metallurgical problems in order to effect a greater commercinl saving. With this plan in view, field work was begun in the latter part of May, 1917, and was continued during the summer. E. K. Soper, formerly professor of mining, University of Idaho, and now dean of the mining department of Oregon Agricultural • College, Corvallis, Oreg., visited the mining districts in central and southwestern Idaho and also some of those in the northern part of the St.ate. D. C. Livingston, professor of geology at the University of Idaho, Moscow, Idaho, also visited some of the mining districts in central Idaho during the summer; in addition, much valuable information he had gathered on former trips to many other districts is included in this report. Credit is also due Mr. Livingston for the maps covering the State, as well as the bibliography nt the end of each chapter. Thomas Varley, superintendent of the Seattle mining experiment station of the Bureau of Mines, spent a short time in the field, principally in the mining districts in central and . northern Idaho, and made a brief visit to the southwestern districts with Mr Soper. The field work of Mr. C. A. Wright, metallurgical engineer of the Bureau of Mines, in direct charge of the cooperative work, was chiefly in the Coeur d'Alene region. Mr. Wright visited nearly all of the mining districts in the region and devoted most of his time to studying the milling methods. The results of the investigation are set 1iorth in this bulletin. The bulletin aims to give the l9Calities of the various mining districts, and the nature of the present operations and those that have been carried on in the past. The geology is discussed only in a general way, the descriptions being intended more especially to bring out the types of ore deposits and the character of the ores, a knowledge of which is essential in determining the proper treatment of the ores. The writers do not wish to imply that all districts mentioned in this bulletin were visited during the summer of 1917, for a great deal of the material has been gathered from other reports, especially from publications of the United States Geological Survey. However, it is hoped that this report will be of help to those who are interested in mining in the State of Idaho. The plan is to continue the field work and subsequently publish the results of the investigations in much more detail, with greater emphasis given the metallurgical treatment of the ores and the problems involved.

Jan 1, 1919

Core samples, which were collected by the author from the Busang prospect, East Kalimantan, reflect a progressive evolution of a large magmatic-related hydrothermal system that is comparable to that encountered in many similar systems elsewhere in the Pacific region. The initial, localized deposition of sheeted porphyry quartz-molybdenite veins took place at high temperatures and fluid salinities, and at relatively deep levels. This was followed by an extensive phase of phyllic (sericite-quartz-pyrite ¦ tourmaline-apatite) wallrock replacement and vein formation. Propylitic (epidote-chlorite-carbonate-quartz) alteration was formed marginal to the phyllic assemblages. These porphyry-related events were centred in the Southeast Zone, and are probably associated with the emplacement of a felsic intrusion at depth. This event contributed only trace gold to the system. The early stages of hydrothermal activity were followed by an episode of quartz (¦ adularia) û carbonate û base metal sulfide veining, which was accompanied by argillic (illitic-kaolin clay) wallrock alteration. This event was sulfide-rich in the Central Zone and carbonate-dominated in the Southeast Zone. Gold mineralisation was observed in Central Zone drillcore to be associated with both sulfide, as well as carbonate, deposition. A final stage of epithermal-style quartz ¦ stibnite û realgar veins are, in the Central Zone, locally gold-bearing. The latter two events are interpreted to be associated with the late-stage exsolution of metal-bearing brines from the felsic intrusion that formed the earlier porphyry quartz-molybdenite veins and widespread phyllic-propylitic alteration.

Jan 1, 2002

By Paul Kunze

When a new bridge was needed across the upper reaches of the Yellowstone River in Montana, removing the old concrete bridge piers became an environmental concern for the highway department engineers. The location is about fifty miles downstream from the north edge of Yellowstone Park. The determination was made by the federal and state agencies charged with protecting the resource, that the old piers had to go but the river bed had to remain unchanged. Concerns were expressed that removing the concrete presented the potential for environmental damage to this protected portion of the river. These concerns prompted the state to place stringent restrictions on the contractor in the way they carried out the demolition and disposal of the piers. The reinforced concrete masses had to be removed to an elevation at least fifteen feet below the river bed and every bit of concrete debris had to be removed from the river channel. Explosive removal was discouraged, but the only other options: saw cutting, mechanical or chemical breaking, were not viable.

Jan 1, 2014

By W. A. Lang

"I.-IntroductionAn attempt bas been made in this paper to provide a basis for appraisal of the future of the coal briquetting industry in Alberta by outlining the processes used for briquetting various ranks of coal, by specifying the requirements of a briquetted fuel, by indicating .the status of the industry in the United States, by giving developments in Western Canada, by assessing costs of processing, and by discussing briquetting researches in progress. Much of .the detail bas been omitted since this might mask, rather than reveal, the more important phases of the problem. Reference will be made when possible to published articles where many of the details can be obtained.It should be stated at the outset that, in the writer’s opinion, there are three possible developments in Alberta as regards briquetting: (a) an expansion of the briquetting of the fines of • non-coking and coking coals of semi-anthracite, and of low and medium volatile bituminous rank; (b) the processing of the fines of high-volatile C bituminous coals; and (c) the upgrading of the lower rank high-moisture sub-bituminous coals. Details of the chemical and physical properties of these coals can be obtained in publications of the Research Council of Alberta (1, 2), and of the Fuel Research Station, Bureau of Mines, Ottawa (3).Semi-anthracite and low and medium volatile bituminons coals occur in the mountain areas of Alberta, where, during the upthrust of the Rocky mountains, the coal beds served as the sliding surface. This resulted in the coals being; crushed and consequently they contain a h1gh percentage of fines. In some cases they are high in mineral matter and require to be cleaned before being processed. However, the cleaning of fine coal is both difficult and costly. Both the amount of fines present in the mine-run coal and the amount of mineral matter associated with the coal have increased through the introduction of mechanized mining and through the recovery of coal by stripping operations."

Jan 1, 1950