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By L. Katgerman, H. J. Brinkman, J. Duszczyk

"The phase formation sequence in the in-situ synthesis ofTiB2 in A1 from elemental A1, Ti and B powders is identified with a combination of DSC and XRD. After the melting of A1, A1B2 and A13 Ti are formed at the contact areas between A1-B and A1-Ti. The influence of variations in starting composition on the reaction kinetics is explained in terms of there effect on the different processes in the formation sequence. Parameters in the starting composition that were investigated are; fraction ofTiB2 forming reactants, non stoichiometric Ti:2B ratio's, and addition of alloying element Cu.It was found that a liquid Al phase is necessary for the in-situ TiB2 forming reaction from the intermediate A1B2 and A13 Ti phases. If all Al is consumed by the formation of A1B2 and A13 Ti the TiB2 formation is halted until the decomposition of A1B2 and A13 Ti .Overstoichiometric amounts of B are needed for complete conversion of the Ti, present in A13Ti, into TiB2 This is explained by the fact that some of the stable A1B12 phase is formed after the decomposition of A1B2•The addition of Cu leads to an increasing reaction rate in the A1-Ti reaction. A possible explanation for this is that the A1-Cu liquid penetrates more easily between the Ti and its surface oxide than the unalloyed A1 liquid."

Jan 1, 1998

By Regina N. Tempel, Laurie S. Balistrieri, Lisa L. Stillings, Lisa A. Shevenell, Maggy F. Lengke

Dexter pit lake, within the townsite of Tuscarora, Nevada, has been in existence since 1990 and provides a natural laboratory for the study of cycles of trace elements associated with ore deposits (e.g. As, Cu, Pb, and Se). Our goal in this study is to develop and calibrate methods of geochemical modeling that may be applied to estimating the concentrations and fluxes of trace elements in pit lake systems. Our initial modeling work considers limnology, hydrology, wall rock mineralogy and geochemistry, benthic fluxes, and colloid composition. Results from our work may be useful in evaluating water quality in the arid West.

Jan 1, 2000

By Jin Qiu

Experiments were performed to determine the extent of minor element elimination that occurred when mixtures of copper smelter dust and copper concentrate, were calcined under vacuum. Almost complete removal of the As, Sb, Bi and Pb occurred due to the conversion of the minor element compounds of these elements into their highly volatile sulphides by reaction with sulphur from the concentrate. Heat and mass balance calculations of the slag-blow in a copper converter found that ~30 tonnes of the vacuum calcine could be used to produce 100 tonnes of copper as white metal. The use of dirty concentrate as the sulphidizing agent in the vacuum calcination means that the minor element treatment capacity of the smelter complex could be increased by 60 %. Also the productivity of the converters may be increased by up to 8 % due to the supply of copper values and oxygen in the calcined mixture.

Jan 1, 2005

By S. J. Haynes

"This paper documents the characteristics of the different quartz veins, and their relation to gold, in the turbiditic Meguma domain of eastern Nova Scotia. Eleven different types have been distinguished in the greenschist facies on the basis of form, internal structure, mineralogy, wallrock alteration and crosscutting relationships to each other and to regional structures. Gold is present as rare visible disseminations in host rock slates and in ore-grade, early-formed veins, that pre-date the formation of upright Acadian folds and intrusions of Devonian granitoids. Four vein types pre-date Acadian folding. Five gold-deficient vein types are associated with Acadian folding (syndeformation); whereas two gold-deficient vein types clearly post-date this deformational event: Previously unreported, wall rock alteration is associated with early crosscutting and semiconcordant auriferous veins. In contrast, early stratiform veins are devoid of wallrock alteration. It is suggested that the auriferous vein arrays formed as submarine exhalitive systems over synsedimentary tensional faults and that the Meguma domain may represent the opening of a basin similar to the modernGuaymas rift .IntroductionThe term ""turbidite-hosted gold deposits"" is introduced to distinguish gold deposits contained within a turbiditic sequence of wackes and shales (or their metamorphosed equivalents) from gold deposits in other types of sediments. Usage and justification for the term is similar to ""carbonate-hosted lead-zinc deposits"" or ""volcanogenic massive sulphides"". A range of different characteristics can be present in individual deposits, some of which may be indicative of specific deposit types in the same manner that volcanogenic massive sulphides can be subdivided into ""Cyprus type"", ""Kuroko type"", ""Besshi type"", etc. Historically, gold deposits hosted by turbiditic flysch were an important class of quartz-vein gold mines in the 19th century. They included the goldfields of Victoria, Australia, Otago, New Zealand and Nova Scotia, Canada. Production from most of these fields had ceased by World War II and interest in this type of deposit waned. However, the recent exploration interest in gold has resulted in both re-assessment of the classical mining camps and the discovery that ""turbidite-hosted"" gold deposits are present in many parts of the world.Mapping of the regional geology and gold deposits of the Megumadomain of Nova Scotia was carried out by E.R. Faribault of the Geological Survey of Canada between 1886 and 1939. Faribault produced a comprehensive series of maps and reports for each gold district, a compendium of which was published by Malcolm (1929)."

Jan 1, 1987

Currently raw brown coal is fired in the Latrotx; 'ahcc th,iki~, Lanying with it two major penalties, (a) boiler efficiency of 65 - 70 per cent (in terms of GCV), (b) much higher boiler cost than for black coal. Drying the coal, in energy-efficient, and cost-efficient manner, opens the way to efficiencies of order 88 per cent and enables the lower cost black coal type boilers to be used. With the higher boiler efficiency goes much higher combustion temperatures and the effect of this on radiative heat transfer is a major factor in reducing boiler cost. In a fluidised-bed combustor the temperature is controlled to 800C - 900C. In a pulverised fuel combustor higher temperatures are however achieved and can increase boiler fouling due to the salt content of the coal. This is a problem which needs to be solved. Victoria has the prospect of lifting efficiency from 28/29 per cent to 35 per cent, of reducing carbon dioxide output correspondingly and reducing cost of power stations. So far as gasification is concerned, efficient removal of liquid water from the coal is important to the overall efficiency.

Jan 1, 1992

By L. J. Cabri, J. M. D. Wilson, R Lastra

An image analysis program can search for gold minerals in polished sections by scanning about 100 x 100 back-scattered electron images at a magnification of x400, allowing gold grains as small as 1 micrometre in diameter to be detected. Typically, a c.15 h overnight search of a product smaller than 45 micrometres will scan c.1 500 000 particles, providing data that are not easily obtained through manual operation of an optical microscope. The program locates grains of the correct brightness, acquires gold X-rays from them by wavelength-dispersive spectrometry, filters the data to remove artefacts and record the images and stage locations for subsequent retrieval. At the end of the run, the program allows the operator to verify and identify the grains found. Industrial studies at Canmet have included determining the nature of gold in cyanidation tailings, checking the mineralogy and size of gold grains in samples from an Indonesian Cu-Au concentrator and locating and measuring gold liberation and grain sizes in an ore

Jun 21, 1905

By Douglas G. Jay

"Transfer points on belt conveyors have long been a source of problems for both designers and users. Conveyors are generally given a low priority in new equipment layout, thus designers are often forced to compromise due to space limitations. Consequently, for this reason as well as for reasons of initial economics, many conveyors are supplied with less than adequate transfer points.Although not intended as a cure-all, a number of existing installations have been modified with the result that spillage has been reduced to a minimum and belt life has been extended. The most striking modification consisted of replacing conventional rigid frame idlers with five-roll catenary idlers.Although catenary idlers can be traced back to the early 1900s in North America, with a patent having been issued in Washington, D.C. as early as May 29, 1907, the practical application of this concept has only recently reached North America. Major installations include applications at St. Lawrence Cement in Oakville and Iron Ore Company of Canada in Sept-Iles, as well as belt conveyors at Stelco's Nanticoke plant and yard conveyors at Syncrude in Alberta. These installations were part of major capital expenditures for new facilities and included complete conveyor systems.However, this article will discuss the use of catenary idlers on existing rigid frame conveyors for the purpose of absorbing the energy of falling lumps, protecting conveyor belts and reducing spillage. We will deal specifically with an installation at Inco Metals Company in Sudbury, Ontario, where approximately 40 five-roll catenary idlers were installed on a 42-in.-wide belt conveyor handling ore located under the railroad car dumper at the Clarabelle Mill. Before-and-after photographs clearly show the tremendous improvement in the cleanliness of the location, and the savings in maintenance costs and extended belt life have prompted Inco to consider modifying other conveyors."

Jan 1, 1982

By G. Bacon

The past decade has witnessed unprecedented growth in the development and implementation of solvent extraction technology in the extractive metallurgy of nickel and cobalt. Solvent extraction is proving to be a powerful tool, opening new opportunities for simpler, more cost efficient and environmentally sound metal refining processes. These advances, however, could not have been possible without the cooperative efforts between the nickel industry and the people and organizations involved with reagents, materials and equipment development and supply as well as solvent extraction research, aided by the accumulated knowledge and practical experience from the copper and uranium solvent extraction operations. This paper provides an overview of these developments and some of the challenges ahead.

Jan 1, 2002

By Thom Seal, S. J. Jung

This paper will combine three SME annual meeting presentations on reducing gold inventory in cyanide heap leaching. Information on Part I – Side slope leaching (SME 2003), Part II – Determining the dry zones using geophysical resistivity (SME 2004), and Part III - Presents a new technology “Hydro-Jex”, to introduce the required lixiviants to the un-leach or under-leach zones in heaps (SME 2005). This paper will describe how Newmont Mining Corporation continues to improve the economics of the heap leaching process for precious metals recovery.

Jan 1, 2005

By C. M. McKinney

The Bureau of Mines analyzed 626 crude oils from 546 oilfields in the United States that produced 2,500 BOPD or more during at least 1 of the last 3 years. Included also are crude oil analyses from eight fields that produced less but which were located in areas having few or no fields that produced 2,500 BOPD. The tables show the geographical and geological source, general characteristics. and determined and computed analytical data for each sample. The analyses were made according to the Bureau of Mines routine method and are directly comparable to other previously published analyses.

Jan 1, 1966

By H. C. Weed

THE Inspiration Consolidated Copper Co., located in the Globe-Miami district at Inspiration, Ariz., became a producer of copper in 1915. From 1915 until 1948, 116,278,000 tons of ore were produced from underground workings by the block-caving system of mining. In April 1948, open-pit ore production from portions of the ore body was started and earlier plans for block-caving in these areas were abandoned. The change was due to economic conditions.

Jan 8, 1950

By L. R. Todd

Gold Fields' Mesquite mine, located in southeastern California, heap leaches low grade gold ore at an annual rate of 2.7 Mt (3 million st). Ore is crushed in a two stage open circuit and belt agglomerated prior to loading on the leach pads. Since initial heap construction in October of 1985, a number of operating practices have been modified and several agglomeration techniques have been tested in an effort to improve percolation and reduce leaching time. Findings to date are discussed.

Jan 1, 1987

Nowadays, technology has improved to extract dimensional stone blocks at quarry sites and also to process these at processing plants for making slabs and tiles. In the process of quarrying and processing, performance evaluation of machinery is very important to achieve optimum output at minimum cost with improved technology. Cost analysis of improved technology includes parameters such as manpower, energy consumption, tool consumption, depreciation, maintenance and also others. The chainsaw machine with long boom and rail in marble quarries and multi-diamond wire saw machine for slab making from granite blocks at processing plants have recently been introduced in India. Thus, a study was carried out under a research project on these machines to assess their suitability. In this paper, performance evaluation and cost analysis of chainsaw and multi-diamond wire saw have been carried out with existing machines on the basis of research findings.

Dec 6, 2010

By Paolo Cavalcoli, Marco Ziller

"ABSTRACT: In the year 2010 the State of Denmark together with the Municipality of Copenhagen, launched a very important and complex Project : the complete construction of a new double Subway Line :the CITYRINGEN.Copenhagen is the capital with a metropolitan population of 1,9 million.This line is like a ring placed in the very town center which includes all the most historical and monumental buildings and churches, with a total length of 17 km, and the presence of 17 stations plus 4 service shafts.The buildings have been built in the last centuries in an area where the groundwater is near to the surface and there are lakes and channels: the techniques adopted were advanced for those times, but limited as far as regards settlements and resistance to horizontal movements.The soil consists in 2 main groups.1.Upper sediments of the glacial ages : thickness total = 5-20 m composed by clay- silt-sand-gravelcobbles- granite boulders and flint in blocs and in layers : frequency and size of these obstacles wherenot determined.2.Limestone layers : 2a. upper limestone : highly fractured ,highly permeable2b.Itermediate limestone : less fractured, medium permeability.2c. Lower limestone : almost not fractured, low permeability.2d Bryozoan limestone : composed by fossils with microscopic dimensionsIn all the limestone formations there are important layers of flint , having thickness variable up to 3 m and important extensions. Water : in a part of the areas of the Cityringen the water is drinkable and utilized in the public waternet.Pollution: there are polluted zones due to previous industrial activities. Benzene areas have been identified, and for those areas special protections against pollution have been implemented.METROSELSKABET ,the public owner of the Cityringen,has set as priority to operate for the construction of the Cityringen the full protection of the environment and the respect of all the stakeholders :Very strong limits for the exhausted gas emissions have been introduced, by far stronger than those applied from the State of Denmark, very strong limits for the acceptable noise emission. And last but not least very important safety measures and procedure to avoid any accident on site."

Jan 1, 2014

By J. M. Toguri, K. Grjotheim

It is known 1,2 that the equilibrium between titanium metal, TiCl2 , and TiCl3, in a solvent of molten metal chlorides, is influenced both by the total amount of dissolved titanium and by the type of solvent. Assuming that the trivalent titanium forms the complex ion Ti111 Cl4, the equilibrium reaction may be expressed by the following equation, (Me) TiIII cl4+ 1/2 Ti = 3/2 TiII cl2+ (Me) Cl The ideal ionic equilibrium constant for this reaction is, Where the N's are the molar ionic fractions in the equilibrium melt, and (Me) the different types of cations present in the equilibrium mixture. The following thermodynamic relation is derived between Kand the concentration of cations in the equilibrium melt, mix The N"S are the equivalent ionic fractions, and so forth are constants corresponding to the standard changes in free energy for reactions in melts where only the cation indicated is present, and f (y1) is a function of the activity coefficients in the equilibrium mixture. When this term vanishes, a simplified linear relationship between In Kideal and the concentration is obtained. The simplified relationship has been applied with satisfactory results to the experimental data of Mellgren and pie,' and Kreye and Kellogg.2 MANY existing methods for the production of light metals involve the reduction of their respective metal halides in the presence of salt melts composed of alkali or alkaline earth chlorides. In such a solution phase, the light-metal halide may undergo stepwise reduction from a higher, to a lower valence, and finally to a zero valent state. In this connection, the disproportionation equilibrium is of great interest. In the case where the higher valence is three and the lower valence is two, the disproportionation equilibrium may be written as follows, 3 Me11 = 2 Me111 + Me [I] If this equilibrium occurs in a salt melt containing a large excess of alkali chlorides, a typical ionic melt is obtained. It is then possible to formulate the cation equilibrium: 2 Me+h' + Me = 3 Me++ [II] Reaction [11] is analogous to a cation exchange reaction. It has been shown thermodynamically that the equilibrium constant for such a reaction in 2

Jan 1, 1960

By Austin E. Dwight

IT has been shown by Oelsen and Wever' that the effect of a solute element on the allotropic transformation in iron is dependent upon the quantity

Jan 1, 1957

By John Feddock

A recent increase in energy demand has resulted in the rapid growth of coal consumption in the People?s Republic of China (PRC), which is the largest coal producer and consumer in the world. Reportedly, the safety issues in Chinese coal mines have been improving, but the number of fatalities and serious injuries continues to be alarmingly high. The number of fatalities from catastrophic accidents have prompted researchers to review the Chinese mine safety situation and to look for potential solutions. Marshall Miller & Associates, Inc. (MM&A), along with various collaborators, has investigated these issues as part of its work on various projects in the PRC and has discussed the concerns with relevant Chinese officials. Preliminary investigations by MM&A of coal mine accidents during 2001?2006 in the PRC indicate that 65%-78% of the total fatalities were the result of gas explosions and roof falls in underground mines. Even though the drainage of methane has been practiced for decades, current practices do not always produce satisfactory results due to technical constraints and equipment limitations. Based on prior experience of in-seam degasification at the Daning Coal Mine located in Shanxi province, MM&A believes that in-seam directional drilling technology can be a viable solution to degas the low-permeability Chinese coal deposits. This paper 1) reviews current Chinese coal mine safety conditions, 2) analyzes the advantages/disadvantages of current degasification practices in China, and 3) presents the pre-mining degasification practices for the longwall panel at the Daning Coal Mine.

Jan 1, 2007

By Jack A. James

Lancaster Lime and Stone Corporation developed a quarry operation in 1971 and 1972 for the production of high calcium limestone and construction aggregates, or roadstone. The quarry operation is situated in southeastern Pennsylvania in the northern part of Lancaster County. The geology of the high calcium limestone deposit had a powerful influence on all aspects of planning this operation. My purpose is to trace the influence of geology throughout the planning and thereby point out the discipline that geology imposed on the planning, and indeed, continues to impose on the operation. Lancaster Lime and Stone Corporation is one of four wholly- owned subsidiary companies of Kurtz Materials Corporation. Kurtz Materials Corporation, through its operating subsidiaries, is a supplier of basic materials to the construction industry including crushed stone, ready mixed concrete, concrete masonry units and a wide range of precast and prestressed concrete products.

Jan 1, 1973

The University of New South Wales (UNSW Australia) has been a world leader in the development of innovative virtual reality technologies over the last 15 years. AVIE (Advanced Visualisation and Interactive Environment) was developed by iCinema as a collaborative venture between UNSW?s Faculties of Engineering and the College of Fine Arts. This is the world?s first 360°-surround, virtual reality (VR) stereo projection theatre system. The School of Mining Engineering at UNSW Australia has developed 18 different virtual reality modules aimed at mine safety training and mining engineering education. These modules are being regularly used in both the mining industry and the university. The School of Mining Engineering is continuously involved in the development of different modules. Research is also currently being conducted on the implementation of other technologies into this environment. Artificial intelligence (AI) and fuzzy logic are tools that the authors would like to consider implementing in future module development. This paper will review current research in both these areas and consider options for applying these technologies.

Jan 1, 2014

By RT White

For many years the concept of life cycle costing (LCC) was promoted for decision making in corrosion protection systems. Nevertheless, the application of LCC was limited. Input data was often sourced from suppliers and met with scepticism. As a result final analysis was often insufficiently rigorous to meet the needs of Project Managers in sound decision making. The need for expediency often resulted in non-optimal corrosion protection system specifications. With improved communications and the global reach of industries, case history data, based upon actual performance has been able to provide input to substantiate decision making. However, today?s focus upon sustainability whereby environmental, economic and even social aspects enter into decision making has extended LCC into Life Cost Analysis (LCA). In an LCA analysis energy and environmental inputs into systems are compared as part of an overall assessment. The development of Agenda 21 at the Rio summit of 1992 has challenged the countries of the world to look at sustainable development in every economic activity. This ranges from construction to mining to electricity production to automotive production, use and disposal. The protection of buildings, infrastructure and transport systems is part of the needs of sustainable development. Zinc based corrosion protection has been an important part of the arsenal of the corrosion protection industry. This paper will highlight the use of LCC and the development of LCA with reference to the use of zinc based protection systems in a number of important industries.

Jan 1, 2006