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By Enver Alan, MerkeziYapı

People are migrating because of economic, social, natural and political reasons. These natural and humane factors effects the distribution of populations. The need for tunnels has grown in order to provide a comfortable life and reduce losses such as waste of time, labor, energy, efficiency and so on. It is inevitable to carry out excavations in rock tunnels (shears, platforms, lines, connections, wastewater, distribution, energy, transportation etc.), that will be built by excavating with conventional method, by controlled blasting regarding with constrains. In this study of applied explosives engineering the blasting applications are evaluated, which were carried out for research and development purposes at Yenisahra Station tunnels in Kartal Formation which was built with the aim of solving İstanbul's transportation problem within the framework of the Kadıköy-Kartal Metro Project. Twenty-four shots were made by using explosives in 60 blastholes that were drilled in the tunnel faces, which were located between and outside of two different faults. Six microphones were used to measure the air shock and eight geophones were used to measure the parameter values of the vibrations (particle velocity, frequency, displacement, acceleration, amplitude, wavelength etc.), which were placed at predetermined points of the surface, occurred during the blasting applications. Data from the geophone and microphones were recorded on six seismographs. The coordinates and the distances between the shot points and the measurement stations are determined by an electronic theodolite. The total number of seismic records, recorded in seismographs, is 118. The number of records of vibrations that crossed the faults is 42 and the number of records of vibrations that did not cross the fault is 76. The particle velocity, frequency, amplitude, acceleration, displacement and wavelength were measured in transverse, longitudinal and vertical directions. The total number of measurements is 354. By evaluating all seismic records, the effect of delay intervals, faults and scaled distances on the particle velocity, frequency, amplitude, displacement, acceleration, wavelength and air shock were investigated. When the vibrations formed during the Research & Development (R&D) blasts were examined, it was determined that the parameter values of vibrations that crossed the faults are lower than the ones that did not cross the faults. In addition, when the particle velocity values of all vibrations are examined according to the present circumstances, it is determined that the waves did not cross the fault in all delay intervals are superposed in all directions, and that the least superposing occurred in the 50 ms delay range.

By Robert M. Matyas, P. E. Sperry, Robert J. Smith, A. A. Mathews

INTRODUCTION The first Dispute Review Board (DRB) was utilized on a tunnel project 20 years ago. Increasingly utilized on a wide range of construction projects, DRB's are becoming the norm on tunnel and underground projects. This paper summarizes the growth in this usage, uses observations and experience to establish that barriers to the utilization of DRB's are more perceived than real and that many arguments against the DRB concept are not valid, and notes some of the salient elements that should be considered in practice to optimize DRB effectiveness. The purpose of the paper is to provide an annotated checklist for current and prospective users. The basic concept, structure, and operation of DRB's are described elsewhere and will not be repeated here (ASCE, 1991). DISPUTE REVIEW BOARD USAGE A compilation of Dispute Review Board usage for tunnel and underground projects to January 1994 indicated use on 63 contracts with a cumulative construction value of $3.8 billion and a total of 60 disputes settled. As of that same date, DRB's were planned for another 63 contracts with an estimated construction value of $4.7 billion. (A listing of these 126 projects is available from the authors.) This success and popularity have spread to other civil projects as well as process and building construction. The increase in DRB usage has been exponential. See Figure 1.

Jan 1, 1995

By Rossana Bezerra de Azevedo Vasconcelos Seabra de Melo

O presente estudo apresenta um método de avaliação de desempenho de operadores nas análises químicas que caracterizam o minério de ferro. São eles: Ferro total (Fe), sílica (SiO2), alumina (Al2O3), manganês (Mn), fósforo (P) e perda por calcinação (PPC). O desempenho é avaliado em termos de precisão e veracidade. Estes dois indicadores primários são combinados num secundário denominado de indicador de “confiabilidade metrológica”. O método foi aplicado nos laboratórios da Mina (no estado do Pará) e do Porto (no estado do Maranhão) de uma empresa mineradora onde foi possível: 1) conhecer o desempenho de cada laboratório assim como conhecer o desempenho de cada operador; 2) identificar os pontos fortes (identificar o procedimento que leva a melhores desempenhos) e oportunidades de melhorias (atuar nas causas, capacitar); 3) equalizar a forma de executar cada uma das tarefas com as melhores práticas identificadas; 4) proporcionar oportunidade de desenvolvimento técnico dos profissionais envolvidos no processo. O desempenho neste indicador tornou-se critério avaliação de aptidão para executar análises.

Aug 2, 2018

Aaby, Alton O , (S'47) Univ of Minnesota, Mimeapolis, Minn Aaby, Waldo S , (S?48) Univ of Minnesota, Minneapolis Minn Aalde, Kaare, (S'48) Univ of Nevada, Reno, Nev Aaring, Floyd D , (S'48) Univ of Oklahoma, Nor man, Oka Aaronson, Hubert I , (S'47) Carnegie Inst of Technology, Pittsburgh, Pa Abbott, Peyton Osborn, (S'46) 1502 Westover, Austin 21, Texas Abel, Malcolm D , (S'47) Univ of Texas, Austin, Texas Aberg, Richard S , (S'47) Univ of Minnesota, Minneipolis, Minn Abrahamson, Guy C , (S'43) 420 W Dennis St , Wilmington, Calif Abrahao, Benjamin, (S'46) Escola Politeenica da Unnersidade, de Sin Piulo, Braizil Achter, Meyer R , (S'46) Carnegie Inst of Tech , Pittsburgh, Pa

Jan 1, 1952

By lonkion M. Font

Due to the known disadvantages of the use of iron silicate slag in the nickel converting stage, i.e., high metal losses, high magnetite content, and low fixation of impurities in the slag, the development of the new proposed "ferrous calcium silicate slag" for smelting and converting processes of nickel is very promising. Hence, considering the successful experimental results of using CaO base slag for the nickel smelting process, a study based on a detailed comparison for the phase equilibrium, and the minor elements distribution between the NilS2-FeS matte with either FeOx-CaO or FeOx-Si02 base slag was investigated. The main results are summarized as: no difference in the nickel losses between both slags was found at high nickel content in the matte, and the fractional distribution analysis for arsenic and antimony pointed out their preferential fixation in the calcium ferrite slag rather than in the iron silicate slag. Considering the energy and pollution issues, the technical feasibility of using calcium ferrite slag in a converting process of the Bessemer matte will have a prominent future for the nickel industry.

Jan 1, 2003

By Ronald F. Balazik

This Bureau of Mines study identifies and examines the costs of Federal, State, and local environmental protection controls on domestic phosphate rock mining, The costs include the expenditures needed to comply with government regulations and the effects that these expenditures and regulations have on supply. The study analyzes costs of environmental impact assessments, air and water quality standards, reclamation laws, potential solid waste controls, and local government restrictions. In addition, an industry survey and the Bureau's Minerals Availability System (MAS) are used to evaluate land management policies that restrict access to phosphate resources, Conclusions drawn from these analyses confirm that (1) domestic phosphate mining has incurred substantial control costs and may be subject to significant new regulatory costs in the next several years, (2) certain environmental controls can discourage mining investment, (3) environmental policies governing land-use controls affect the disposition of sizable phosphate resources, and are key determinants in the development of those resources on the Federal do- main, and (4) environmental costs could diminish the competitiveness of domestic producers.

Jan 1, 1983

By Jonkion M. Font

Due to the known disadvantages of the use of iron silicate slag in the nickel converting stage, i.e., high metal losses, high magnetite content, and low fixation of impurities in the slag, the development of the new proposed "ferrous calcium silicate slag" for smelting and converting processes of nickel is very promising. Hence, considering the successful experimental results of using CaO base slag for the nickel smelting process, a study based on a detailed comparison for the phase equilibrium, and the minor elements distribution between the Ni3S2-FeS matte with either FeOx-CaO or FeOX-Si02 base slag was investigated. The main results are summarized as: no difference in the nickel losses between both slags was found at high nickel content in the matte, and the fractional distribution analysis for arsenic and antimony pointed out their preferential fixation in the calcium ferrite slag rather than in the iron silicate slag. Considering the energy and pollution issues, the technical feasibility of using calcium ferrite slag in a converting process of the Bessemer matte will have a prominent future for the nickel industry.

Jan 1, 2003

By Henry Kreisinger, WALTER T. RAY

General statement.-The briquetting tests conducted by the technologic branch of the United States Geological Survey had their beginning in the testing of coals and lignites at the Louisiana Purchase Exposition, St. Louis, Mo., in 1904. Briquetting tests were made at the fuel-testing plants at St. Louis, Mo., and at Norfolk, Va. Similar tests to be made at the experiment station of the Bureau of Mines at Pittsburg, Pa., form an essential part of investigations looking to the determination of the fuel value of the coals and lignites belonging to or for the use of the United States. The tests have comprised (1) the manufacture of briquets to determine the adaptability of different coals and lignites to the process and the merits of different binding materials; (2) physical tests to establish the fitness of the briquets to withstand weathering, transportation, and handling; and (3) steaming tests to prove the calorific value of the briquets in boilers of different types used by the Government, and, by comparison with the raw coals, the benefits to be derived from briquetting. Details of the tests have been issued in other publications. list of Government publications on fuel testing and briquetting is given at the close of this volume. Tests at Norfolk.-The fuel tests conducted at Norfolk included a detailed investigation of a number of Virginia and West Virginia coals that are bought by the United States Government for the Navy and for use in constructing the Panama Canal, and are extensively used by the merchant marine, manufacturing plants, and railroads. Through a cooperative arrangement with the Navy Department steaming tests of the coals were undertaken to determine the relative merits of the same coal when burned raw or as briquets in marine boilers. Preliminary arrangements were made between Joseph A. Holmes, then expert in charge of the technologic branch of the United States Geological Survey and now director of the Bureau of Mines, and Rear-Admiral Charles W. Rae, Chief Engineer of the United States Navy. The tests were made on board the U. S. torpedo boat Biddle, designated for the purpose, beginning December 6, 1907, and ending January 27, 1908. The coal used in these tests came from the Sewell and Beckley beds in the New River district of West Virginia. With the particular equipment used in the tests both coal and briquets were far. from smokeless; consequently the data of this bulletin are applicable only by analogy to parallel operation with a coal more nearly smokeless, but nevertheless applicable with much reliability. The possibilities of coals of different composition are indicated by the data to be published in a bulletin of the Bureau of Mines, wherein the present authors describe a number of tests in which only a very slight amount of smoke was emitted while burning raw coal from the Pocahontas No.3 bed, West Virginia, and briquets made therefrom at rates of combustion very much higher than any rates used in the torpedo-boat boiler. At a combustion rate of 120 pounds of the Pocahontas briquets per square foot of grate surface there was scarcely any smoke. It was the original intention to make a set of preliminary steaming tests alongside a dock (which tests furnish material for this bulletin) and to finish with a set of running tests at sea; but the running tests were never made, for lack of time and men.

Jan 1, 1911

By Floyd C. Kelley

THE literature of the last decade is rich with information relating to the cause and means of control of grain growth in pure metals, but is deficient concerning the role diffusion plays in grain growth, although during this period many new products that depend on diffusion for their properties and success have been developed. Among these are cementation products, produced by calorizing, chromizing, and carbonizing, or by mixing, pressing, and sintering powdered metals such as Syke's iron-molybdenum die material, Genelite, and Elcon Metal (copper, tungsten) etc. This is a fertile field for new developments, but before it can be utilized to the fullest extent there must be a thorough investigation of the processes by which diffusion and grain growth take place. Grain growth plays no small part in the process and certainly the physical properties of these products depend largely on the grain size and state of equilibrium produced. The field of investigation does not end here, but may be extended to the effect of diffusion on impurities, segregations and dendrites in the broad field of ferrous and non-ferrous metallurgy. A number of years ago the author investigated several of these cases and noted, with striking regularity, the pronounced effect of diffusion in promoting recrystallization and grain growth. An example of this phenomenon is given in his paper on chromizing1 which contained photomicrographs of large radial or columnar crystals produced by diffusion of chromium in the solid state. Another manifestation of this effect was discussed by Austen,2 who showed the part hydrogen plays in the decarburization of steel and the effect of diffusion upon the grain structure. DIFFUSION OF METALS IN IRON It seems to be a general law, whenever two metals are brought into intimate contact at a temperature at which diffusion takes place, that a comparatively rapid, or abnormal, grain growth results. The grains

Jan 1, 1928

By Floyd C. Kelley

The literature of the last decade is rich with information relating to the cause and means of control of grain growth in pure metals, but is deficient concerning the role diffusion plays in grain growth, although during this period many new products that depend on diffusion for their properties and success have been developed. Among these are cementation products, produced by calorizing, chromizing, and carbonizing, or by mixing, pressing, and sintering powdered metals such as Syke's iron-molybdenum die material, Genelite, and Elcon Metal (copper, tungsten) etc. This is a fertile field for new developments, but before it can be utilized to the fullest extent there must be a thorough invest,igation of the processes by which diffusion and grain growth take place. Grain growth plays no small part in the process and certainly the physical properties of these products depend largely on the grain size and state of equilibtiuni produced. The field of investigation does not end here, but may be extended to the effect of diffusion on impurities, segregations and dendrites in the broad field of ferrous and non-ferrous metallurgy. A number of years ago the author investigated several of these cases and noted, with striking regularity, the pronounced effect of diffusion in promoting recrystallization and grain growth. An example of this phenomenon is given in his paper on chromizingl which contained photomicrographs of large radial or columnar crystals produced by diffusion of chromium in the solid state. Another manifestation of this effect was discussed by Austen,2 who showed the part hydrogen plays in the decarburization of steel and the effect of diffusion upon the grain structure. Diffusion of Metals in Iron It seems to be a general law, whenever two metals are brought into intimate contact at a temperature at which diffusion takes place, that a comparatively rapid, or abnormal, grain growth results. The grains

By W. L. Remick

THE hydrotator coal-cleaning process was developed as an economic necessity to meet the ever-increasing demand for an inexpensive method of cleaning coal down to the sizes ordinarily referred to as "dust." As the most urgent demand seemed to be in the anthracite field, all experimental work has been conducted in that territory during the past 2 years, with the exception of a few months during the strike of 1925-26, when some experiments were performed in the Alabama bituminous fields. The first commercial plant was constructed at the Middle Creek Colliery of the Philadelphia & Reading Coal & Iron Co., Pottsville, Pa. This plant is now operating. APPLICATION The field of application of the process is: 1. Cleaning anthracite fines, ordinarily described as "slush" or "silt." Slush contains all sizes from %2 in. down to and including "dust." (Anthracite passing a 32-in. mesh is also referred to as No. 2 Barley and No. 4 Buckwheat.) 2. Cleaning sizes too fine for recovery by other methods. 3. Removal of coal from sand circulated in the Chance sand-flotation process. 4. Cleaning of bituminous sizes. from 3/8 in. down to "dust. 5. As equipment for the performance of the froth flotation process. 6. Other separating, extraction and _washing. processes which may be considered outside the realm of coal cleaning. PRINCIPLE OF OPERATION Fig. 1 shows the method of classification practised under the Hydrotator patent:1 In coal cleaning the machines are operated as "hindered settling" classifiers, the flow of solids and liquids being so controlled that the units may be combined in series.

Jan 1, 1927

By G. O. Rading, B. O. Odera, M. J. Papo, R. Couperthwaite

"Platinum-based alloys are being developed with microstructures similar to nickel-based superalloys for potential high-temperature applications in aggressive environments. Since the chemistries of nickel and platinum are similar, Pt-based alloys can be made with gamma prime ~Pt3Al precipitates in a gamma (Pt) matrix. Currently, the Pt-Al-Cr-Ru system is one of the bases for developing Pt-based alloys, where Al allows the formation of thePt3Al precipitate and also gives protection from the alumina scale formed, Cr provides oxidation resistance and stabilization for the L12~Pt3Al phase, and Ru provides solid solution strengthening in the (Pt) matrix. Four Pt-Al-Cr-Ru-V and two Pt-Al-Cr-Ru-V-Nb alloys were made, with compositions based on a quaternary alloy, ~Pt82:Al12:Cr4:Ru2, which hadpreviously been identified as having optimum properties. Four of the as-cast alloys had the targeted two-phase structure of ~Pt3Al and (Pt), and two were single-phase ~Pt3Al. Vanadium partitioned more to (Pt) than to~Pt3Al. There was an improvement in hardness compared to the quaternary alloys. The best addition of V was ~15 at.%; higher additions resulted in brittle intermetallic phases of the Pt-V system. The effect of Nbcould not be ascertained because of its high losses."

Jan 1, 2015

By Sadettin Bagdatli, Ali Kahriman, Umit Ozer, Alper Celtikci, Yucel Karakus

Due to population growth and rapid urbanization in Turkey, the need for the construction of residential units, transportation and infrastructure facilities has become increasingly more pressing. Since rock units encountered in the surface and underground in the construction of the subway, infrastructure and housing facilities, it is a necessity to use blast excavation methods. In recent years, large housing construction projects have been carried out especially in Turkish metropolitan areas, involving foundation excavations giving rise to great amounts of earthmoving. Since rock units encountered during foundation excavations are usually hard and solid, excavation with conventional machinery proves to be inadequate and unproductive, hence the necessity for the application of blasting technology.

Jan 1, 2014

Iran possesses very large copper resources, estimated to contain around 4-5% of the world's known copper inventory. There are several small private sector copper mining operating in the country, but Iran's copper industry is dominated by the state-owned National Iranian Copper Industries Company, which operates the world-class Sar-Cheshmeh open-pit Mine. This mine was developed in 1970s before the 1979 Islamic Revelation by the Atlantic Richfield Company (ARCO), the former Anaconda Copper Mining Company. Current Iran?s copper cathode production is about 250,000 mtpa and recently it is targeted to reach to 700.000 t by 2014. The required finance for this target is estimated US $2.25 -b, i.e. US $5000 for each tonne capacity. The copper content of the mineable reserves of the country is estimated about 19 Mt. It is not unlikely this amount increases in close future. Currently, almost 30 projects consist of mine, concentrator, smelter, refinery, acid plant, leaching, bio-leaching are underway. These projects are a golden opportunity for the local and foreign companies, but the recent sanctions are very challenging that all studied in this paper.

Jan 1, 2012

By Hassan Ghaffari

? HPGR Process/Overview ? HPGR vs. SAG ? The Manufacturers ? Mine Operations using HPGR ? Projects by Wardrop/Tetra Tech ? Economic Benefits ? Questions Main Operating Parameters ? Press Force (N/mm2) ? Roll Speed (m/s) ? Moisture Content (%) ? Feed Particle Size Distribution Specific throughput M* = throughput/D*L*V (ts/hm3) Flake thickness/strength in balance with the compressing force (floating roll situation)

Aug 1, 2013

By Anthony T. Iannacchione

The Roof Fall Risk Index (RFRI) is a new method introduced by the National Institute for Occupational Safety and Health (NIOSH) to assist the underground stone mine operator in 1) assessing defects the mine strata and 2) rating the relative roof fall risk these defects pose. The RFRI utilizes observational techniques to identify defects in the roof strata caused by local geologic, stress, and mining conditions. Assessment values for ten defined defect categories provides the foundation for estimating a range of risk conditions between 0 and 100 that define the potential for a roof fall. This paper examines how the defect information is collected using two field verification sites and proposes methods to analyze the RFRI data. These examples provide information on how well the method replicates observed conditions and how it might be applied in practice.

Jan 1, 2006

By Cleiton Rodrigues de Vasconcelos, Elizeth Oliveira Alves, Kleber Gonçalves Bezerra Alves

Em virtude da periculosidade do Pó de aciaria (PAE), práticas alternativas, como a reinserção do resíduo no processo produtivo, ou sua incorporação em outros materiais fizeram com que a reciclagem tenha se tornado uma via para este subproduto. O presente trabalho tem como objetivo identificar as áreas de desenvolvimento tecnológico de utilização do PAE, avaliar a potencialidade de reaproveitamento e reciclagem do resíduo oriundo do processo de produção do aço carbono, comparando as características obtidas do PAE analisado com os requisitos indicados através da análise de patentes. O PAE produzido no estado de Pernambuco foi caracterizado pelas técnicas de Fluorescência de raios X (FRX), separação granulométrica via peneiramento, distribuição do tamanho de partículas, Difração de raios X (DRX), Microscopia eletrônica de varredura (MEV) e Espectroscopia por energia dispersiva (EDS). A prospecção tecnológica foi realizada nas bases de patentes europeia EPO e na base nacional de patentes nacional do INPI. As análises realizadas mostraram que o material apresentou aproximadamente 28,5% de suas partículas com granulometria inferior a 53μm, composto em sua maioria por ferro e zinco presentes na forma de óxidos, organizados nas fases franklinita, zincita e magnetita. A baixa granulometria e composição química possibilitam a sua aplicação no campo dos materiais cerâmicos, bem como sua reinserção no processo de fabricação. O resíduo estudado apresentou características similares com os demais resíduos observados nas patentes.

Mar 1, 2019

By Arthur B. Foote

THE ball mill has superseded stamps for the reduction of gold ores in most of the recently designed plants, partly because stamps are not suited to die fine grinding required for flotation, and partly to save space and construction cost. Experience with these new mills seems to confirm the idea that it is more difficult to recover bold from a ball-mill product than it is when stamps are used for crushing. Microscopical examination of particles of gold that have passed through a ball mill show that the gold has been pounded into exceedingly thin flakes coated with a talcy surface, making it more difficult to save by amalgamation, flotation, or concentrating. Bearing in mind that gold is extremely malleable, it seems reasonable that this should be so. Contrast the action in a stamp battery, where the crushing is by impact in the presence of mercury, to the grinding and rolling under pressure in a ball mill. It is well known that a better recovery can be obtained by panning or amalgamation from a sample of ore that has been crushed by mortar and pestle than from one reduced on a bucking board.

Jan 1, 1937

By M. Tangstad, B. Monsen, H. Midtgaard, R. Ishak, M. Syvertsen, I. Solheim

Charcoal is an interesting reducing agent because it is produced from growing wood which is renewable and does not contribute to global warming, provided that there is a balance between the felling of timber and growth of trees. In the biocarbon project the possibilities for using charcoal is investigated as well as other biological based and renewable reductants for ferroalloy production. The background for the project is that the Norwegian ferroalloy producers wish to contribute to reduction of CO2- emissions. This paper focuses on the use of charcoal instead of coke for the production of manganese alloys, and the consequences of doing so. Results from practical SiMn smelting experiments on a pilot scale have previously been reported, where only 12-14 % Si in the metal was obtained when charcoal was used. Recently we have attained satisfactory 18 %Si also for charcoal, but good results are indeed dependant on good furnace performance. There is no tradition for using charcoal for manganese production in Norway. A change from using mainly coke to the use of some charcoal will demand new routines for furnace operation, raw material and off-gas handling. Hence, characteristic properties of charcoal, which may cause change of furnace operation, have been measured and are compared to coke. The following results are presented: ?Thermal abrasion strength together with CO2- reactivity; important parameters for the performance of the upper part of the furnace. ?Coke-bed resistance; it will increase with the use of charcoal (a review of new results). ?Slag reactivity; a relevant method for testing slag reactivity of industrial reductants is of interest. The suggested method can serve for comparing slag reactivities towards graphite.

Jan 1, 2007

By Leandro Miranda Nascimento

A maior parte da produção mundial de aço passa pela conversão de minério de ferro em grandes altos-fornos, tendo o coque como uma das matérias-primas. Por um lado, boas propriedades mecânicas a quente do coque, como o CSR e CRI, são necessárias para que o consumo de coque seja o mínimo, pois é também, junto com os óxidos de ferro, um dos maiores componentes dos custos variáveis do ferro gusa. As misturas dos vários tipos de carvões minerais utilizados exigem a participação de uma fração Hard, a mais cara e com maior poder de coqueificação, e de uma fração Soft, mais barata e inerte. Logo, quanto maior for a participação do Hard mais caro será a mistura a ser coqueificada. Uma maneira de aumentar a fração de Soft na mistura de carvões, reduzindo o custo da mistura, e ainda assim obter um coque com boa qualidade é aumentar a densidade a granel da mistura. Para isso alguns métodos já são empregados com sucesso, como o Stamp Charging e a Briquetagem Parcial. Este artigo apresenta um novo método, que consiste na densificação da mistura de carvões dentro do forno via dispositivos de vibração. Foram realizadas simulações físicas a frio e em escala reduzida para avaliar o potencial de aumento de densidade a granel da técnica. Os resultados mostram um ganho de aumento de 30% da densidade a granel da mistura.

Aug 17, 2017