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Beyer Barometric Condenser The Ingersoll-Rand Co. is now offering to the trade complete steam­condensing plants for all service conditions. This equipment includes the Beyer barometric condenser, for' which the company has secured the patent rights, Imperial duplex and Ingersoll-Rogler straight-line reciprocating dry vacuum pumps and, where required, Cameron simplex and centrifugal pumps. The Beyer barometric condenser is of the counter-current type, in which air and cooling water flow in opposite directions. The steam inlet is at the bottom of the condensing v el, the water inlet above and the air-removal opening at the top. The sheets of cooling water over owing the pool at the inlet point meet the entering steam. The two are brought into intimate contact by conical baffle plates which assist the water to absorb to its full capacity the latent heat of the steam. The non-condensable air liberated in the condensing action rises through the falling water to the removal point at the top, being cooled to practically the temperature of the incoming water. It is also to be noted that ample opportunity is given for the removal of the air content of the water before

Jan 8, 1916

By A. Timur

Fluid flow properties of porous media have long been of interest in such varied disciplines as geology, geophysics, soil mechanics, and chemical, civil, and mechanical engineering. This interest has resulted in numerous models of porous media that have been proposed, tested, and found to be useful under, at best, only special circumstances. A critical review of most of these models is given by Scheidegger. 1 The application of each new tool to the study of porous media has helped to test some of the existing theories and to form new ideas based on the new parameters being measured. In the application of nuclear magnetic resonance (NMR) techniques to the study of the properties of fluids in porous media, the theoretical studies of Korringa et al.2 resulted in a model for the relaxation of spin polarization of protons in a hydrogenous fluid in a pore of a solid. Seevers3,4 verified this model, established a method for measuring the surface-to-volume-ratio distribution in a porous medium, and proposed a technique for determining specific permeability in sandstones. In the present investigation, the uses of NMR methods are extended and a simple model of porous media is developed from an analysis of pulsed NMR measurements. In this model, the pore spaces of a porous medium are divided into three groups on the basis of their surface-to-volume ratios. To evaluate predictions of the NMR model, laboratory measurements of spin-lattice relaxation time, porosity, permeability, and residual (irreducible) water saturation were conducted on more than 150 sandstone samples obtained from four oil fields in North America. Applications are discussed for estimating the volume of movable fluid, ?p, and the specific permeability, k, of sandstone samples. The former parameter, which can be considered as producible porosity, is expressed by ?p = [1 -- (Swr/100)]? , .... (1) where + is porosity in percent of bulk volume and Swr is the residual (irreducible) water saturation in percent of pore volume at a capillary pressure of 50 Psi. Fast, nondestructive laboratory methods are described for determining porosity, movable fluid, and permeability of sandstone samples from measurements with a pulsed NMR (spin-echo) apparatus. Procedures are given for adapting these methods to samples of irregular shape and small size. Theory General In the Korringa, Seevers, and Torrey2 (KST) model the observed decrease in the spin-lattice relaxation time, T1, of protons of a hydrogenous liquid contained in the pore spaces of a porous solid is attributed to an increase in the correlation time for the random motion of the water molecules and to the presence of paramagnetic centers at the liquid-solid interface. This KST model predicts the observed relaxation time of a hydrogenous liquid in a pore of a solid through

Jan 1, 1970

This appendix contains the list of equipment selected for the capitol cost estimate, with the respective quotations from their vendors/manufacturers. A vendor response report along with a separate equipment and motor list has been included in the first part of this appendix.

Jan 1, 1979

By André Boyer

El presente artículo señala que los revestimientos de goma en los molinos son un aporte positivo en la minería -en tanto reducen las horas de parada y su costo por tonelada por una mayor duración. En ese sentido, las parrillas de descarga en goma aumentan el rendimiento de los molinos entre 20 y 25% de su capacidad por overflow.

Jan 1, 1975

Jan 1, 1902

By A. J. Williams

"Conventional base metal milling practice normally consists of crushing, grinding and cyclone classification followed by flotation. It is the authors' belief that the commencement of flotation after cyclone classification leads to inferior metallurgical results and that implementation of flotation of grinding mill discharges can result in increased recovery due to reduced overgrinding, reduced activation of contaminating minerals and improved dewatering circuit results due to the production of coarser concentrates.The concept of recovering minerals from the discharge of grinding mills is not new! Gold concentrators have utilized jigs and flotation cells while iron ore plants have employed magnetic separators to recover gold and magnetite respectively from the discharge of grinding mills. More recently, a Reichert cone has been used to recover sulphide and oxide base metal minerals from screened rod mill discharge. 1To the authors' knowledge, the first application of flotation of base metal minerals from the discharge of a production plant grinding mill was at the Lake Dufault concentrator of Corpor'1tion Falcon bridge Copper. Located 10 miles north of Noranda, Quebec the Lake Dufault concentrator commenced operations in August, 1964.The installation of flot11tion cells in the Lake Dufault grinding circuit proved so successful that an identical system was installed in the Manibridge concentrator of Falconbridge Nickel Mines Limited. Located 90 miles southwest of Thompson, Manitoba the Mamibridge concentrator commenced operations in June, 1971 and due to exhaustion of economic ore reserves discontinued production in May 1977."

Jan 1, 1984

By Gabrielle Luana Jimenez

Aparelhos eletroeletrônicos como computadores e televisões são constituídos por telas de cristal líquido, que ao se tornarem obsoletos são classificados como resíduos, e dispostos em aterros sanitários. Entretanto, na composição das telas de cristal líquido há metais de valor agregado, como o índio (In). Com a fundamentação no processo de reciclagem de telas de LCD, este estudo propõe a recuperação e quantificação desse metal que é encontrado na forma de ITO (óxido de índio e estanho). Para tal feito, foram empregadas rotas hidrometalúrgicas, tendo como principal etapa a lixiviação. Como parâmetros de controle, os ensaios de extração sólido-líquido foram realizados em temperaturas que variam de 50 a 80°C. Com isso, foi obtido resultado de extração do índio em cerca de 60% em massa, nas condições de 60°C e após 4 horas de lixiviação.

Aug 17, 2017

By S. Schina

Part of the Imittos Western Peripheral Motorway in Athens is the twin road tunnel in the vicinity of American College, with 20m excavation diameter. In the paper, the environmental and other requirements, the geometry and the geological – geotechnical characteristics of the rock formations in the construction area are given. Information regarding the modeling and analysis methods that are used for the design of the temporary support, the final lining and the wedge and slope stability analysis is described thoroughly. Finally, the results of the analyses are compared with these of measurements and general remarks during the construction of the tunnels.

Jan 1, 2001

Recent developments in diamond drilling practice have been chiefly 'concerned with modifications in drill design and 'operating technique whereby an increase in daily footage rates and reduced footage costs have been achieved without any marked improvements in the recovery of core. This trend is perhaps due to the general acceptance by the mining and drilling engineer alike of the belief that diamond drilling has definite limitations in exploratory work on mineral deposits characterized by irregularities in continuity and grade, such a belief arising from the fact that drilling technique has not yet evolved coring devices to ensure the full recovery of the rock and mineral formations penetrated.Current diamond drilling operations at Moonta and Wallaroo Mines, carried out by the South Australian Department of Mines, have attained remarkable results in completely eliminating core-loss by the use of a special double-tube core barreI.It is considered that assays of borehole samples taken with this special barrel have a reliability comparable, if not superior to that of similarly situated mine samples and, provided they are spaced satisfactorily, can be used as, a basis for calculating tonnage and grade. Formerly, with only partial core-recoveries, positive borehole results on narrow irregular lodes, such as those in the Moonta and Wallaroo Mines, could be accepted mainly as indications of the presence of mineralization, and could have only a limited bearing on estimates of ore reserves.The value of this special double-tube core-barrel lies In the fact that it guarantees good core recovery and, therefore, good samples, and eliminates the need for sludge-sampling, which is prone to give unreliable assay results from several causes, such as gravity concentration in the bottom of the hole and return water losses which cannot be overcome.In view of the increasing demand for minerals and the probability that the search for them will be carried on largely by boring, it is felt that it would be of interest and value to direct the attention of mining engineers to core-recovery results obtained by diamond drilling plants in South Australia and the features of the special core-barrel, designed by the writer, which has made this possible. Also, the writer is desirous of placing on record two other core-recovery devices designed to extract accurate samples in relatively soft or unconsolidated formations. The latter are used with percussion and calyx plants, respectively and their value has been proven on phosphate rock and coal deposits in South Australia.

Jan 1, 1943

By Edgardo Caro Orellana

El yacimiento Coroccohuayco fue descubierto durante el transcurso del segundo año de exploración (1971-1973) a través de un programa de Levantamiento Geológico del cuadriángulo Velli-Yauri, Cusco, considerándose como un ejemplo de prospección científica. En esta perspectiva, el objetivo del texto señala cuáles son los métodos de exploración empleados para dicho yacimiento. Entre los métodos del estudio regional tenemos la fotogeología, aeromagnetría y gravimetría y entre los métodos del estudio local están la geoquimiica, geofísica y perforación diamantina. Asimismo se menciona la prospección geofísica por el método de polarización inducida y la perforación diamantina.

Nov 20, 1978

By Mario Del Risco V

El presente trabajo señala los diseños de fracturamiento hidráulico en los pozos de petróleo, donde se experimenta los nuevos fluídos y aditivos y se perfeccionan los procedimientos utilizados. Asimismo se describe el diseño, ejecución, clases de fracturamiento y costos del mantenimiento de este tipo de operación.

Nov 20, 1967

Experimental results are presented that test the hypothesis that the descaling behaviour of stainless steel slabs following reheating is controlled by interfacial roughening at the scale-steel interface. In this investigation, two stainless steels were considered: type 304 (austenitic, with 18% Cr and 8% Ni) and type 412 (ferritic/martensitic, with 11.6% Cr). It was found that the entanglement that arises at the scale-steel interface was in fact effective in maintaining scale-steel adhesion, under the mechanical descaling conditions used. In the case of type 304, descaling proceeded by fracture along chromite layers, which formed (by internal oxidation) on the austenite grain boundaries; for this steel, the extent of descaling depends most strongly on austenite grain structure, and not primarily on the conditions in the reheating furnace. In contrast, type 412 samples descaled only at the edge of the entangled zone, and showed a greater sensitivity to the reheating conditions; specifically, higher free oxygen in the reheating gas and longer reheating times were found to increase the residual scale thickness. Key words: stainless steel, reheating, scale, entanglement, descaling, fayalite, internal oxidation, grain structure, free oxygen.

Jan 1, 2003

By G. L. Smith

This paper consolidates the key elements of seven contributions, on strategic long-term planning, to two of the three international conferences on Strategic versus Tactical approaches in Mining held over the period 2005?2008. The holistic concept of strategic long-term planning as developed and implemented at Anglo Platinum is described. Consideration is given to the planning cycle, principles supporting the construction of the long-term plan, and aspects of unique best practice as developed in Anglo Platinum. Further description of Anglo Platinum?s approach to corporate governance, including the processes, methodology, systems, unique tools and techniques that are applied to value and select capital investment options is also given.

Jan 1, 2009

By N. Barton, E. Quadros

This paper addresses the prediction of groutable joint apertures, grout penetration limitations, and possible grout take volumes per cubic metre of rock, as a result of 5 to 10 MPa pre-injection pressures ahead of tunnels. Joints are obviously opened more than in the preceding Lugeon tests, and many rock mass properties can apparently be improved if stable micro-cement based materials are used. Cet article concerne la prédiction des ouvertures des fractures injectables, les limites de pénétration du coulis et les volumes injectés par mètre cube, d’après les résultats des injections à l’avant tête des tunnels sous pressions de 5 à 10 MPa. Evidemment les joints s’ouvrent plus que dans les essais Lugeon précédents. Maintes propriétés du massif peuvent apparemment être améliorés si l’on emploi des coulis a base de micro-ciment stable. Die Publikation widmet sich der Prognose injizierbarer Kluftöffnungen, Grenzwerte für Injektionsreichweiten und erreichbarer Injektionsvolumen pro Kubikmeter injizierter Fels, durch die Anwendung von 5 bis 10 MPa Vorinjektionsdrücken vor der Tunnelfront.Die Klüfte werden offensichtlich weiter geöffnet als in den vorhergegangenen Lugeon Versuchen und mehrere Felsparameter können durch die Verwendung von stabilisierten Micro-Zement basierten Injektionsmaterialien verbessert werden.

Jan 1, 2003

The Research on Refined Gold Bullions Surface Upgrading

Sep 13, 2010

By Robert A. Siokler

Approximately 75 percentage of the earth's land surface is comprised of shale or shale-like materials. Shale itself is composed of the residue from an almost infinite variety of weathered parent materials which have undergone deformations ranging from intense to negligible. Under standard test procedures, shales exhibit a very wide range of physical properties particularly if the test specimen is subjected to a change in moisture content, when the original test values may vary from 0 to 100 percentage. It is this wide variation in physical property values compounded by its ubiquitous presence that makes shale such a problem material to engineers. In reviewing the literature relating to shale, it is evident that the "problem" has been approached from many directions. In order to understand why shales behave as they do, investigators have sought mineralogical, geological, chemical, electrical, and physical answers. Each study yields valuable academic information, but few contribute much of value to the engineer in the field. Many valid relationships between shale strength or competency and clay type, clay content, organic content, water content, grain size, cementation, density, porosity, etc, have been established. Yet it is very difficult to extend these understandings to the in situ condition with results that can be used by the field engineer. One major reason earlier work has not produced better information lies in the ambiguity of the definition of shale. It is apparent that no one laboratory parameter can be successfully used to provide sufficient engineering information to properly describe in situ conditions. For example; shale with swelling clays will produce low strength values provided: the swelling clay is in sufficient quantity, the clay is dispersed throughout the medium involved, and there is a low value of cementation. Shales with high unconfined compressive strengths have been found with very low shear strengths. Sandy shales often provide as many ground control problems as clay shales. Shales of similar nature may provide good roof conditions in one part of a mine yet in another part of the same mine the apparently identical shale may cause substantial problems. A clear need exists to classify shale in a manner which will enable the engineer to better predict the strength and durability of shale-like materials. Studies at the University of Missouri-Rolla (UMR) have focused on finding parameters which influence durability and competency, while being discretely discernible through uncomplicated testing. Initial research concentrated on distinguishing shale8 on the basis of standard physical tests such as: unconfirmed compression, triaxial shear, and slake durability. As results accumulated, however, it became evident that moisture content played a much greater role in determining competency than had been recognized previously. As a result the focus of the research turned to developing tests which would evaluate the influence of moisture on shale behavior. The above work then became a foundation for a second phase of investigation in which a suite of standardized tests were developed to provide a classification procedure. From this study five tests were identified as being critical: Moisture Activity, Atterberg Limits, Submersion, Unconfined Compression, and Shore Hardness.

Jan 1, 1986

The Torington Lodes.This paper describes investigations into mineralogical, petrological and structural associations of cassiterite in occurrences of economic value. The work was carried out in three mines, during a number of years, in the hope that the, data collected might be helpfulin the search for occurrences of cassiterite in stanniferous zones and reduce unproductive exploratory work. Tin-bearing lodes at Torington, in the New England district, New South Wales, have been worked since 1880, and the locality is the most important centre of lode tin occurrence in the, State. The township of Torington is 18 miles westerly from Deepwater, a station on the Great Northern Railway, 446 miles from Sydney.The tinfield forms part of the Mole Tableland, which has an altitude between 3,000 ft. and 4,000 ft. above sea level. The country rock, in which the stanniferous lodes occur, is granite of Permian age, which has been intruded into Carboniferous claystone. An inlierof claystone is exposed to the west of the stanniferous area, 'and in it, close to' its contact with the enclosing granite, are occurrences of wolfram and bismuth. These minerals, together with chalcopyrite, pyrite, arsenopyrite, zinc blende, galena and molybdenite, in very small quantity, are associated with cassiterite in lodes traversing the granite, particularly near the claystone, but decrease in amount with distance from the contact. Their occurrence is sporadic and usually causes no trouble in dressing the cassiterite concentrate, the final product containing less than 1% of total penalisable impurity. In Curnow's mine, pyrite, galena and molybdenite have been observed at 700 ft. from surface.The granite is of the biotite type and its structure may be divided into four groups, or classifications, arising from segregation processes during cooling and consolidation. The four classes, in order of extent of distribution, are:1. Granite of normal type, in which the constituent quartz felspar and mica, have a particle size approximately 14, in.2. Porphyritic granite, in which the felspar particles are from % in. to lin. in size, that of the quartz and mica approximately % in.3. A fine-grained granite, in which the particles of all constituent minerals are % in. or less in size;4. A rock of highly siliceous ground mass containing very small particles of felspar and almost negligible biotite.Type 1 is the general type of granite in all mines of the field; types 2 and 3 may occur as large masses, or all three classes may merge rapidly one into the other, and all be disclosed in 20 ft. of driving. Usually, however, the segregations are massive, but are not associated with any special horizon. For instance, a mass of porphyiiticgranite extends from surface to a depth of 440 ft., for a distance of 350 ft. south from the New England main shaft. The upper levels of Curnow's mine, 14" mile south-east, are in normal granite, but a restricted mass 'of porphyritic granite occurred between Nos. 5 and 6 levels, or 400-500 ft. below the collar of the shaft...

Jan 1, 1950

By III, Peter J. Rogers, J. Gordon Ogden

A study is described which attempts to identify the chemical factors of common concern to environmental and exploration geochemistry as indicated by recent work in both disciplines in Nova Scotia. Cores taken in lake sediments define geochemical baselines for the modern and pre-industrialisation periods. The investigation of lake and stream drainage indicates the presence of numerous chemical and organic factors that can be attributed to man's activities, such as construction and energy consumption. Geochemical surveys of lake and stream sediments are used to locate potentially toxic, high risk areas in Nova Scotia. Rapid change occurs in most surface drainage systems with the possibility of numerous chemical reactions taking place. It is found that spatial and temporal variations in the chemistry of modern and recent sediments are of interest to exploration and environmental surveys.

Jan 4, 1992

By Bhaskar B. Thapa, Christopher Laughton, Michael P. Bruen

At Fermilab, located in Batavia, Illinois, a 4,000-foot underground complex of tunnels and caverns is being excavated on a decline of six percent, at depths of up to350 ft, below grade. The site geology consists of dolomitic and shale formations overlain by glacial till. Since the start of construction in March 2000, work to date has concentrated on the excavation and support of the Target Hall cavern, which is characterized by a low rock cover and a final lining of shotcrete. Ground vibrations, noise levels, and rock movement were monitored during excavation by drill and blast methods to prevent damage to experimental facilities, impacts on surrounding communities, and to allow evaluation of cavern performance. The cavern design was based on a UDEC numerical analysis that was validated during construction by comparison to encountered conditions and measured cavern movements.

Jan 1, 2001

By M. H. Moys, J. A. Finch, A. R. Laplante

"A detailed review of ball milling circuit control practices in industry has been carried out. Based on fundamental process performance objectives, a standard system for base-level control of most ball mill installations is presented. This system is simple, inexpensive, and provides the major economic benefits available from contemporary automatic control technology.Value Analysis of Grinding OperationsValue analysis (or engineering, or management), originally developed by Lawrence D. Miles of the General Electric Company (1), focuses on the identification of value (product or process worth versus cost) and provides a systematic procedure for its improvement. A recent research and development project involving the application of the principles of value engineering to grinding operations has provided a basic technoeconomic model of grinding processes (2). The functional objectives of the ball milling process and the means to achieve value based grinding circuit control originate from this study.The Need for Grinding Circuit ControlThe economic effectiveness of a process is determined by the quality or value of the product and the related processing costs. If the inputs (both the raw feed and the applied processing work) are absolutely constant, the product characteristics and the process efficiency will be determined only by the engineering design. The need for and degree of process control is therefore determined by the nature of variations or upsets in the process inputs, and the extent to which these effect product value and operating costs."

Jan 1, 1988