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By Mark Sheppard

DURING the winter of 1937, the writer visited a West Virginia stone, quarry at which the overburden is stripped hydraulically. The quarry is in a bed of limestone, about 200 ft. thick, which outcrops on a hillside above a small river; the quarry face is 175 ft. high. The top of the stone is cut in all directions by erosion channels, which are filled with a tough, red clay. Some of the larger channels are 30 ft. deep and 8 ft. wide, The thickness of the clay overburden ranges from a few inches to 10 ft., the average being estimated as less than 3 feet. The topography of the district is rugged, and the hillside above the quarry face is not suited to the use of the usual mechanical methods of moving dirt. Until hydraulicking was started 10 years ago, the over-burden was dug by hand labor, dumped to the quarry floor and trans-ported to the dump in quarry cars, Cleaning deep channels was a slow and expensive process. When hydraulicking was started, the top of the quarry face was over 200 ft. above the level of the river. The pipe line was carried in a semi-circle around the top of the quarry about 200 ft. from the face and about 50 ft, above it. As there is no adequate supply of water above the quarry, the water must be pumped from the river: As quarrying pro-gressed the pipe line was moved until the discharge points are now over 300 ft. above the river. Water is pumped from the river by a four-stage centrifugal pump having a 5-in. intake and a 4-in. discharge. It is direct-connected to a 200-hp,, 2300-volt, 1760-r.p.m. induction motor. At 1760 r.p.m. the rated capacity of the pump is 750 gal. per minute under a head of 600 ft. The pump is installed in a house of frame construction on the river bank, about 10 ft, above normal water level, which also houses the pump for the mill-water supply. Above the pumps are hoisting hays into which the motors are raised whenever the river reaches flood stage.

Jan 1, 1938

By Rafael C. Castro, John Overton, Gregg Sherry, David A. Sutter

This paper presents an innovative ground support solution developed to construct a tunnel cross-passage for the MUNI Metro Turnback (MMT) Project. A “soft center” jet grouting approach was designed to provide solid ground support while maintaining a soft center to allow for hand-mining of a 2.44 m (8 ft.) wide, 3.66 m (12 ft.) tall and 4.6 m (15 ft.) long cross-passage through soft Bay Mud. Prohibitive costs and schedule impacts associated with mining under compressed air (at the time being used for main tunnel construction) were the catalysts to search for alternative methods for cross-passage construction. Limited surface disruption, relatively low costs, ease of subsequent excavation, nominal schedule impacts and proven local success of jet grouting were key factors in selecting and designing this method of ground support.

Jan 1, 1997

By M. Rudman, L. Pullum, L. J. W. Graham

Centrifugal pumps are the workhorse of hydraulic conveying systems but their performance is derated when viscous non-Newtonian fluids, such as pastes and/or coarse solids are present. The reduced performance for purely viscous Newtonian fluids may be calculated using techniques such as the Hydraulic Institute method, but similar deration for non-Newtonian fluids is not so easy to apply. As part of the AMIRA P599 project investigating high concentration suspension pumping, centrifugal pump tests were systematically conducted on a wide range of non-Newtonian coarse particle suspensions. Suspension sup to 38% v/v of coarse particles with mean diameters in the range of 1.1 < d50< 3.4 mm suspended in carrier fluids with dynamic yield stresses of 0 < t?< 17.2 Pa and shear thinning indices in the range 0.35 < n< 0.79 were examined. Techniques such as the Hydraulic Institute de-ration method require a characteristic shear rate to be assigned before application with a non-Newtonian fluid, and a method based on pump geometry, fluid rheology and flow rate is proposed. This method predicts the dramatic characteristic reduction in head at low flow rates that is often observed and explains why larger pumps are relatively insensitive to this form of head deration. Head deration due to the presence of coarse particles in non-Newtonian carrier fluids is seen to follow similar trends to that of Newtonian suspensions and often dominates the total deration procedure.

Jan 1, 2007

By G. W. Center

This manual is intended to assist federal, state, and local regulatory and planning agencies, the mining industry and consulting engineers in determining the regulatory, environmental, technical and economic constraints influencing the site selection, planning, construction/operation and reclamation phases of a waste disposal facility. The information presented illustrates that factors affecting an individual site may be simple or very complex. This manual discusses methods for making future land use decisions, determining regulatory requirements, evaluating physical, chemical and structural properties of the disposed waste and selecting appropriate waste disposal methods and control techniques. Procedures and guides in the manual will assist personnel in assessing the complexities of waste disposal on a site specific basis. The major types of waste disposal systems are discussed and evaluated in terms of their advantages and disadvantages and applicability to varying site conditions and waste characteristics. Appropriate references following each chapter provide more detailed data on material presented in the text.

Jan 1, 1982

By Robert R. Walden, LaMont West

KENTUCKY&apos;S first acid-grade fluorspar flotation mill, shown in Fig. 1, was placed in operation Aug. 1, 1952, by the Pennsylvania Salt Manufacturing Co. at Mexico, Ky. During 1951 a critical shortage of acid-grade fluorspar developed and it became necessary for the company to produce part of its fluorspar requirements. In 1951 the company purchased the Crider and Lennen metallurgical fluorspar mill and an adjacent stockpile of tailing at Mexico, Ky. The tailing, assaying about 26 pct calcium fluoride, originated from log washer and jig mill concentrators in the area. As the mill did not have a fluorspar dryer or convenient rail facilities, the company leased the Burleson concentrator at Marion, Ky., where these facilities were available. At Marion, Ky., on the Illinois Central Railroad, dry acid-grade fluorspar is transported direct to the company&apos;s Calvert City, Ky., hydrofluoric acid plant.

Jan 5, 1954

By Dean Newman, Michael Behrens, Mark Trim, Justin Arifin

Road tunnels in recent infrastructure projects in Sydney, Australia, are designed to have a fire resistance level of either a 4-hour cellulosic fire or a 2-hour hydrocarbon fire. Where permanent ground support for tunnels consists of systematic rock bolts and relatively thin layer of shotcrete, it is important to ensure that during and after the fire event the ground support is designed/predicted not to pose risks to the tunnel occupant. The global behavior of the ground support can be predicted using finite element analysis, and its resistance is derived with consideration of the material strength degradation due to the elevated temperature.

Dec 1, 2022

By João Alberto Fioresi Altoé

Nas indústrias petroquímicas, nucleares e farmacêuticas o avanço tecnológico tem como objetivo a segurança e confiabilidade dos equipamentos com relação à resistência mecânica e à corrosão. Atualmente, o uso dos aços inoxidáveis superausteniticos é uma solução interessante, para uma maior vida útil dos componentes industriais submetidos a ambientes agressivos, como em meios salinos. Esse trabalho tem como objetivo investigar o aparecimento de pites em um aço comercial superaustenitico de composição química aproximada 25Cr28Ni4Mo em solução salina de cloreto de sódio. O aço foi fundido e tratado termicamente por solubilização a 1050ºC por 1h com o objetivo de eliminar os precipitados. As análises microestruturais antes e após os ensaios de corrosão foram feitas por microscopia óptica e eletrônica de varredura. Observou-se com os ensaios eletroquímicos de Polarização linear e impedância, que o aço inoxidável superaustenítico apresenta excelente resistência à corrosão em meio salino, caracterizado também pelas imagens que não revelaram a formação de pites, mesmo quando submetidos a elevados potenciais.

Aug 16, 2017

By J. K. Stanley

Iron-cobalt alloys in the range of 35-50 pct cobalt are of interest in the electrical industry because they possess the highest magnetic saturation of any magnetic material known. l1,2The magnetic saturation induction of the 35 pct alloy is 24,200 gausses, compared to 21,600 for pure iron (Fig I). This difference is significant in electrical apparatus, whcre weight or space is at a premium. Saturation values higher than that for iron can be attained up to about 70 pct CO hut economics restrict the use to as low a cobalt content as possible without sacrifice of saturation. Fig 2 shows the iron-cobalt equilibrium diagram. Up to the present time, two factors have retarded the use of iron-cobalt alloys in the electrical industry for magnetic purposes.? One is the high cost of cobalt ($I.50 per pound) and the other ig the inherent brittleness of the binary iron-cobalt alloys. Straight iron-cobalt alloys up to 25 pct cobalt are ductile and easy to process to thin sheet or strip by conventional methods of hot and cold rolling, but the alloys containing higher percentages of cobalt, including those for which the saturation magnetization is a maximum (35 to 40 pct), are increasingly brittle with increasing cobalt, at least up to 50 pct, and are consequently difficult to process, either hot or cold. Work by White and Rah13 indicated that iron-cobalt alloys could be made ductile by alloying with vanadium, and after quenching the alloys (vanadium up to about 4 pct) were found to he colt1 rollable to very thin gauges. With this as a background, we resumed our work on these alloys with the objective of developing methods for economical commercial production of wide strip. For this purpose we have concentrated on the 35 pct alloy in order to obtain the highest possible saturation value. Experiments were carried out on many alloy additions to the iron-cobalt alloys and on the response of these compositions to heat treatments. This work finally culminated in a commercially producible iron-cobalt alloy which has been named Hiperco.* Materials StudIEd and Procedur&apos; Binary alloys of iron and cobalt in the range of 35 pct cobalt are difficult to hot work (by forging or rolling) without such additions as C, Mn, Si, V, Cr, Mo, W Or perhaps others. Another beneficial effect of such additions is that they increase to a greater or less extent the strangely low electrical resistivity of these alloys about 10 microohms per cm3

Jan 1, 1948

By J. K. Stanley

Iron-cobalt alloys in the range of 35-50 pct cobalt are of interest in the electrical industry because they possess the highest magnetic saturation of any magnetic material known. l1,2The magnetic saturation induction of the 35 pct alloy is 24,200 gausses, compared to 21,600 for pure iron (Fig I). This difference is significant in electrical apparatus, whcre weight or space is at a premium. Saturation values higher than that for iron can be attained up to about 70 pct CO hut economics restrict the use to as low a cobalt content as possible without sacrifice of saturation. Fig 2 shows the iron-cobalt equilibrium diagram. Up to the present time, two factors have retarded the use of iron-cobalt alloys in the electrical industry for magnetic purposes.? One is the high cost of cobalt ($I.50 per pound) and the other ig the inherent brittleness of the binary iron-cobalt alloys. Straight iron-cobalt alloys up to 25 pct cobalt are ductile and easy to process to thin sheet or strip by conventional methods of hot and cold rolling, but the alloys containing higher percentages of cobalt, including those for which the saturation magnetization is a maximum (35 to 40 pct), are increasingly brittle with increasing cobalt, at least up to 50 pct, and are consequently difficult to process, either hot or cold. Work by White and Rah13 indicated that iron-cobalt alloys could be made ductile by alloying with vanadium, and after quenching the alloys (vanadium up to about 4 pct) were found to he colt1 rollable to very thin gauges. With this as a background, we resumed our work on these alloys with the objective of developing methods for economical commercial production of wide strip. For this purpose we have concentrated on the 35 pct alloy in order to obtain the highest possible saturation value. Experiments were carried out on many alloy additions to the iron-cobalt alloys and on the response of these compositions to heat treatments. This work finally culminated in a commercially producible iron-cobalt alloy which has been named Hiperco.* Materials StudIEd and Procedur&apos; Binary alloys of iron and cobalt in the range of 35 pct cobalt are difficult to hot work (by forging or rolling) without such additions as C, Mn, Si, V, Cr, Mo, W Or perhaps others. Another beneficial effect of such additions is that they increase to a greater or less extent the strangely low electrical resistivity of these alloys about 10 microohms per cm3

Jan 1, 1948

By R. S. Dean

In an earlier paper Dean and Hersberger5/ gave preliminary results a d discussed briefly the use in flotation of organic reagents of the type known in the textile industry as "wetting agents.? These reagents are those with a molecular structure comprising a long hydrocarbon chain attached to a. highly molar or hydrophile group in such manner that ionization is nearly complete in dilute solution and the resultant ionic grouping has a very considerable hydrophile-lipophile unbalance in the structure. As a result of this characteristic structure these reagents are more or less powerful frothers and emulsifiers. Ten the degree of bydrophile-lipaphile unbalance is sufficiently great and specific chemical factors are absent these compounds behave in flotation as noncollecting frothers insensitive to reasonable changes of pH.

Jan 1, 1937

By R. S. Dean

In an earlier paper Dean and Hersberger5/ gave preliminary results a d discussed briefly the use in flotation of organic reagents of the type known in the textile industry as "wetting agents.? These reagents are those with a molecular structure comprising a long hydrocarbon chain attached to a. highly molar or hydrorhile group in such manner that ionization is nearly complete in dilute solution and the resultant ionic grouping has a very considerable hydrophile-lipophile unbalance in the structure. As a result of this characteristic structure these reagents are more or less powerful frothers and emulsifiers. Ten the degree of hydrophile-lipaphile unbalance is sufficiently great and specific chemical factors are absent these compounds behave in flotation as noncollecting frothers insensitive to reason¬able changes of pH.

Jan 1, 1937

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations No. 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the fifth. The data are accompanied by maps showing the location of holes drilled and deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project except the deep holes drilled to test the geophysical anomalies. The locations of those holes show on figure 13 in Volume I. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion of that area.

Jan 1, 1948

By Alexander Malahoff

A shipboard research system capable of operating in waters of up to 2,000 m has been designed and implemented by the Hawaii Undersea Research Laboratory (HURL), University of Hawaii. It uses a remotely-operated ocean bottom survey camera system, ROV, bottom TV grab, the PISCES V submersible, and a submersible emergency recovery system aboard the 225-foot RN KA&apos;IMIKAI-O- KANALOA. All systems are operated from the stern of the KA&apos;IMIKAI with a mounted Caley telearm and articulated A-frame system. The system was designed for multi-purpose use of the telearm for launch and recovery of the PISCES V submersible on a lift recovery line (with or without diver assistance), or night-time operations with an electro-optical cable using either the HURL ocean floor sidescan, or photo and video system operated at 10 m above the ocean floor. The 1.14-inch diameter cable is also used to operate the RCV-150 garage/ROV system. The garage/ROV system has also been designed to act as a submersible rescue system with a submersible lift capability.

Jan 1, 1992

By Junji Shibata

Extraction behavior of Ti(IV) and other metal ions, such as Fe(III), Fe(II), Cu(II), Zn(I1) and Co(I1) from acidic solutions like sulphuric acid and hydrochloric acid was studied in order to recover titanium from the waste solution in Ti02 production. Extractant used was tri-alkyl phosphine oxide whose trade name was Cyanex 923. Then, a study was made of the idea of simulating a countercurrent multistage extraction system, using the results of batch extraction. The simulation was camed out on extraction and saipping behavior for a Ti(1V)-H$O,-Cyanex 923 system. From the simulation result., the optimum operating condition of the system was considered.

Jan 1, 1994

By Bruce E. Holbein, Dennis K. Kidby, Ann L. Huber

World gold production figures and the processes used for gold production indicate a high dependence on both cyanide leaching and carbon adsorption metallurgies. Problems associated with the use of carbon in the treatment of refractory ores as well as economic and environmental considerations associated with the use of cyanide point to the advantages that can be realized through the use of more efficient gold adsorption media and with cyanide recovery. We have developed a process termed AurosaveTM-1 which provides a number of advantages through the use of a new synthetic robust gold adsorption medium, termed Vitrokele TM V-911. This process allows further recovery of gold from a variety of ores and allows for a simplified process for use not involving thermal regeneration or high pressure elution. We have also developed a cyanide recovery process termed Cyanosave ™ which uses Vitrokele TM V-911 and allows efficient recovery of cyanides from decants or tailings and re-use of recovered cyanide. This obviates the high chemical expenses for cyanide destruction where environmental issues require such water and tailings management.

Jan 1, 1998

By Claudio Ballota

Los sistemas de gestión empresarial son importantes -en tanto las estrategias de negocios acompañadas del apoyo de sistemas de información, permiten planificar, ejecutar y controlar el desempeño empresarial. Por ello, la integración de la información en una empresa a través de reportes gerenciales y herramientas de análisis, son fundamentales para cualquier ejecutivo que quiera desempeñarse exitosamente en el mercado moderno. En ese sentido, el presente texto señala la eficiencia del outsourcing de sistemas integrados en la administración de las empresas como un proyecto tecnológico de negocios que está dirigido a todos los empleados de la empresa que interactúan con sistemas para realizar sus tareas operativas diarias y para los gerentes que buscan información para tomar mejores decisiones.

Jul 17, 2000

By Hongmin Zhu, Guihua Wang, Xiangsheng Wang

"The anode process of carbon electrode in fluoride melt was studied by voltammetry and chronoamperometry. Anode gases were analyzed by gas chromatography on-line during controlled-potential electrolysis. Two peaks were observed on the cyclic voltammograms. According to the results of gas chromatography, the first peak was corresponded to the discharge of residual oxide ions, with the formation of CO and CO2. Discharge of fluoride ions occurred at 4.1 V vs. Li+/Li, and leading to the anode effect. With the occurrence of anode effect, small amount of CF4 was detected. As the potential reached 4.5 V, CF4 and C2F6 gas evolution occurred, and the current increased to form the second peak.1.IntroductionIn the primary production of Aluminum and some rare earth metals like neodymium, a departure from normal cell operation known as anode effect results in the generation of perfluorocarbons (PFCs), which have high global warming potentials [1]. Owing to the pressure of environmental protection, considerable research has been carried out to clarify the mechanism of anode effect and PFC generation of industry and laboratory cells in the aluminum electrolysis system [2-9]. The common result on PFC generation is that the PFCs are emitted from Hall-Heroult cells only when they are on anode effect. In this article, we selected LiF, the main electrolyte for the neodymium electrolysis [10-11], to perform further investigation on the underlying kinetics of PFC generation and the nature of the reactions at the electrode.2. ExperimentalAll experiments were carried out in an alumina tube reactor, which was filled with high purity helium atmosphere. Spectrographic graphite crucibles were used, which played the dual role of molten fluoride container and the counter electrode. Lithium fluoride was analytical grade. The experiments were carried out at 900 °C."

Jan 1, 2011

By Isadora Maria Oliveira Anício Costa

Desenvolvimentos recentes no emprego de ligas NiTi superelásticas (SE) na confecção de instrumentos endodônticos rotatórios envolvem a aplicação de tratamentos térmicos nos instrumentos inicialmente produzidos a partir de ligas SE. Neste trabalho foi estudado o efeito de tratamentos térmicos e sua contribuição para a evolução das propriedades funcionais de um fio de NiTi SE. Os fios comerciais de NiTi, aproximadamente equiatômicos, foram ensaiados após o tratamento de recozimento por 1 hora, em temperaturas de 300°C a 500°C, e então temperados em água. A caracterização física do material foi realizada por calorimetria exploratória diferencial e as propriedades mecânicas foram obtidas em ensaios de tração e de recuperação de forma. Os resultados apontaram aumento nas temperaturas de transformação dos fios com o recozimento, o aparecimento da dupla transformação austenita - fase R - martensita B19’ durante o resfriamento. Observou-se também diminuição do módulo de elasticidade aparente e aumento da deformação residual com o aumento da temperatura de recozimento, indicando, em concordância com a variação nas temperaturas de transformação, que o material passou a apresentar o efeito memória de forma.

Aug 8, 2018

By Jorge Luis Barreto

A CBMM aplicou aços microligados ao nióbio de elevada resistência mecânica em caminhões basculantes que operam nas suas instalações de Araxá, com o objetivo de reduzir o peso das caçambas e obter maior desempenho com aumento da carga transportada, redução do consumo de combustível bem como das emissões de CO2. Também tinha o objetivo de eliminar as trincas de fadiga que ocorriam sobre os chassis desses equipamentos. Os caminhões já operam há 12 meses e o objetivo desse trabalho é apresentar os resultados obtidos até o momento. Com a aplicação dos aços de elevada resistência, foi possível desenvolver um novo desenho para sua estrutura e componentes. Houve uma redução de 25% da massa da caçamba o que proporcionou um aumento médio de carga transportada de 40,0t para 41,1t ou 2,7% por viagem, trazendo até o momento, economia de 3,00% no custo total de transporte e redução de consumo de combustível de 8,00%. Não houve trincas ou deformações no sobre chassis que apoiam as caçambas.

Aug 8, 2018

By M. J. Davie, D. S. Ross

"The successful design of a new mine water pumping system is in part dependent upon the accuracy with which the operating conditions can be forecast. This paper outlines the data which should be obtained on water quantity and quality. Methods of modifying the quality are also discussed. Some pumping systems for disposal of sludge are described, citing operating examples. The various types of mine dewatering pumps are described in terms of design characteristics as they affect operating efficiency and installation and maintenance costs. Piping system parameters are outlined. Finally, a hypothetical case study of pumping from a depth of 3,000 ft is assessed, with particular reference to capital costs.IntroductionMany mine operators would agree that the pumping system usually receives a low engineering priority during the design stage, and as a consequence causes some of the most frustrating problems during production. For a ""dry"" mine (up to 200 gpm), design of the pumping system may indeed be simple, but outside of the potash industry such mines are not common. For ""wet"" mines, the pumping system is important because it significantly affects the initial capital and on-going energy costs of the mine and, in the area of sludge disposal, the working conditions and production costs. Indeed, a failure in the pumping system usually has serious, and sometimes disastrous, consequences.The intent of this paper is to outline the factors which should be considered in the design of a pumping system and to describe the types of pumps used in mine dewatering and relate them to practical operating systems."

Jan 1, 1980