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By J. D. Templeton

A petroleum well that is not in use because it has ceased to produce oil/gas economically and dry holes are referred to as abandoned wells. Once a well is abandoned it is plugged with cement and can take anywhere from two days up to a week to cure depending on the number of plugs in the well. Since plugging a well costs capital, most wells are abandoned at the lowest possible cost and with the minimum obligations set by regulation agencies. These wells can present an enduring liability to petroleum companies. However, the depth and abundance of abandoned petroleum wells makes them an economically attractive source of geothermal energy. Geothermal energy harvested from an oil/gas well is a renewable energy source as long as it is extracted in a sustainable manner. The energy can be used to generate electricity, used directly for heating, incorporated into a water desalination process, or used by a heat pump for heating/cooling applications. In this paper we examine the possibility of extracting geothermal energy from abandoned oil/gas wells by studying the heat transfer in underground geothermal heat exchangers installed in these wells. The design configurations for the geothermal heat exchangers embedded inside a petroleum borehole can be a u-tube design or a shell and tube design (i.e. double pipe). Using in-situ gathered information from some representative petroleum boreholes, the effects of key parameters such as geothermal gradient, ground temperature values, and the flow inside of the tubes are evaluated. In order to provide a constant power production the inlet temperature can be adjusted to keep the difference between outlet and inlet temperatures equivalent. Higher differences between inflow and outflow temperatures will result in a less sustainable load put on the in-situ geothermal energy. Adding insulation to certain sections of the designs can minimize the transfer of thermal energy from the fluid to the surroundings. Insulation can also limit the thermal loss between the inflow and outflow tubes in the shell and tube design. Minimizing the energy loss of these designs leads to an increase in the outlet temperature, meaning a higher grade of heat. The sustainability of long term geothermal heat extraction is a balance between the rate at which geothermal energy is extracted and the rate at which the ground formation can replace this heat. Higher outlet temperatures can lead to a larger amount of power generation, and a higher coefficient of performance for heat pump applications.

Aug 1, 2013

By R. Codell, D. L. Hughson

The authors benchmarked the integrated finite-volume code MULTIFLO against the analytical solution of Philip et al. (1989) for cylindrical underground openings. They found that the numerical simulation of dripping threshold flux was consistently higher than the analytical solution for rectangular and unstructured grids. The magnitude of this error was proportional to the alpha parameter characterizing capillarity. This error may bias estimates of seepage into drifts for repository performance towards nonconservatism.

Jan 1, 2002

By Fernando Altamirano

Dado que en las unidades mineras existen problemas respecto al manejo de la información relacionada a la seguridad, salud e higiene tales como que los reportes enviados a las autoridades competentes (MEM, DGM, DGAA, OSINERG, DIGESA, etc.), se hacen en forma manual, generando una revisión y conteo previo tedioso y donde no existe una clasificación o estructuración de la información. En ese sentido, se plantea la utilización de las herramientas tecnológicas modernas para optimizar la administración de la información generada en las operaciones de forma diaria. Este sistema está desarrollado bajo una arquitectura Cliente/Servidor con bases de datos que soportan SQL., que se asegura una solidez en la generación de tablas relaciónales, un desarrollo práctico de las pantallas de entrada, flexibilidad para generar reportes y capacidad de expansión e integración a otras aplicaciones, donde se busca que el usuario se sienta a gusto utilizando su interfase full Windows diseñada para efectuar los registros y operaciones de manera intuitiva y versátil.

Aug 25, 2002

By Clarence Carleton Semple

At a number of mines in eastern Nicaragua, 3.5- or 5-ft. Huntington mills are used for grinding gold-ore after a pre-liminary breaking in jaw-crushers. The smaller mills are made sectional to facilitate transportation to the more difficultly accessible mines. The capacity of the smaller mills is about 20 or 25 per cent. that of the larger, but in proportion to the quantity of ore ground they require more power and are subject to greater wear. The notes herein given are from records of the performance of the larger mills at one of the mines, but, in general, apply to the smaller mills also. The Nature of the Ore. The ore occurred as a series of flat veins in a' highly-decomposed rock, probably alaskite. The primary mineralizatioll comprised pyrite, pyrrhotite, marcasite, chalcopyrite, and quartz; the oxidation-products of which were chiefly hydrated iron oxide or limonite, chrysocolla, azurite, and malachite. The kaolinization of the feldspar of the country resulted in the admixture of a great quantity of clay with the oxidized ore. The quartz was sandy, imbedded in the clay; and probably the greater part represented the residue from the crushed rock in the fissures after leaching, and kaolinization of the feldspar. There was little vein-quartz in the unaltered primary sulphide ore. Only the oxidized ore was mined for the gold that it contained in amouiits that averaged $4 per ton. No specks of gold mere ever seen in the ore, and the gold obtained by panning was always exceedingly fine. The amalgamation-bullion was about 800 fine in gold and from 60 to 80 in silver. The ore delivered at the mill contained from 5 to 15 per cent. of moisture; during the rainy season the quantity was much greater. The moisture and clay made the ore so sticky that it had to be raked over steeply-inclined grizzlies; it hung in the ore-bins,

Jan 1, 1912

By W. S. Weldon

The use of spiral separators for the beneficiation of fine coal typically in the size range -2+0.1mm is now well established process technology. Developments during the mid 1980's resulted in the production of cost effective, efficient large diameter coal spiral separators. Recent developments and research have been geared to optimize metallurgical performance, materials handling and equipment geometry of large diameter coal spiral separators.

Jan 1, 1997

By Mike L. Aziz, Keith D. Ferguson, Glenda Ferris

The Equity Silver mine has been a severe producer of Acid Rock Drainage (ARD) since 1982. The mine was closed in 1994 and a compacted clay cover installed, but ARD continues to be produced. Three permanent employees manage the collection and treatment system at the site. The site still poses a significant environmental risk to the environment and downstream users and requires a high level of diligence. Various stakeholders' perspectives of the risk posed by Equity, and what constitutes acceptable risk, will be examined in this paper from a company operation staff, corporate environmental manager and downstream environmentalist perspective.

Jan 1, 2000

By Henry S. Mackay

The interesting paper recently submitted by Messrs. Tobelmann and Potter1 shows that chemical problems have developed which are of great interest in this new and important branch of metallurgy. Those who realize what a process of this kind really involves will agree that it deserves a better name than '(leaching process." The word leaching conveys the idea that the copper is simply leached out of the ore with acid and then precipitated on iron; the chemistry of such a process would be of little interest. As, however, during the first year's operation of this plant 24,400,532 lb. (11,067,837 kg.) or about two-thirds of the produce, was electrolytic copper, while 7,992,033 lb., or about one-third, was cement copper, it would seem more appropriate to term the process electrochemical. It further appears, from the particulars given, that efforts have been made to have the entire production in the form of electrolytic copper. This could be done if the chemistry of the problem were kept in balance, so that it would not be necessary to discard any solutions that carried copper and acid of commercial value. A process, such as that under consideration, in which the copper is precipitated from solution by electrolysis, the solvent being at the same time regenerated, is one that requires special chemical and electrochemical knowledge and experience if all the copper in solution that has been extracted from the ore is to be successfully and economically produced as electrolytic copper. The object of this paper is to discuss, from the practical and theoretical standpoints, the chemical and electrochemical problems involved in the working of a process of this kind, and which must be solved to keep it in chemical and electrochemical equilibrium. In such a process, if the chemical balance is maintained, a solution can be used alternately as a solvent for the copper in the ore and as an electrolyte of high efficiency for the precipitation of the copper. To maintain the chemical equilibrium and so attain this result, the process must be so controlled that the solu-

Jan 1, 1921

By H. Cecil Spicer

The results described in this article are based on field work conducted during the periods APril-May, 1939, and MaY-JulY, 1940. The United States Potash CO. is mining potash on Government land under a permit from the Department of the Interior and the geophysical investigation mas completed under a cooperative arrangemerit made between that company and the Conservation Branch of the Geological Survey. The writer, a member of the Section of Chemistry and Physics of the Geologic Branch, was assigned to this investigation. Four definite objectives were in mind for the geophysical work in the studies over the salt deposits. The first was to determine the measure of success that could be attained in this type of work with the resistivity methods that were to be employed. These methods had been introduced into the work of the Conservation Branch by Benjamin E. Jones for the investigation of dam sites, and have been used under his direction by the author for such work. If the method proved to be applicable, an l was to be made to contour the top of the salt beds and also the other formation boundaries known to be present in this area. Salt-water aquifers were to be studied in an effort to determine their boundaries, and an attempt was to be made to delineate the potash-bearing beds. Others have made, and reported, resistivity studies over saliferous deposits in different areas. Friedell and Messrs. Schlumberger2 reported geophysical work performed in the disrovery of the salt domes of Alsace; Carrette and Kelly3 described the geology of the same area. Leonardon and Kelly4 published a resistivity curve obtained over the Hettenschlag dome, and a further discussion of this same area was given by the Messrs. Schlum-berger5 in a communication. Messrs. Alty6 described studies 0" salt deposits in which the sing[e-probe method was used. Sinerez7 mentions that electrical methods were tried over salt deposits in Spain. Geoffrey and Charrin8 show a resistivity curve obtained over marl, gypsiferous marl and salt which is similar to that obtained over the New Mexico salt deposits. Kelly9 reported resistivity work performetl with the ground comparator of Zuschlag over the salt deposits near Syracuse, N. Y., where the Salina formation is at a depth of 700 to 800 ft. Some structural studies on the potash basin of Alsace are described by Poldini.10 Another single-probe resistivity study, made over salt deposits in New Mexico, is briefly described by Heiland,ll through the courtesy of Harry Aurand, of the Midwest Refining CO.

Jan 1, 1942

THE science of topography deals with the various natural and physical features of the earth's surface. These features are determined by the manifold constructive and destructive processes of nature, and their many diverse forms and characteristicsare dependent primarily upon geologic structure. Thus it is that a close relationship exists between the rocks of a region and the topographic features of the lJountry wherein they occur. Again, the existence of all sorts of mineral wealth is dependentupon the nature of the rocks, and their extension is directly connected with the topographic features represented upon the enclosing land-area.In studying any district with a view to deciphering its geological structure, to locating any mineral deposits it may contain, and to ascertaining, so far as a surface-examination may show, their probable and economic possibilities, it is therefore ofprimary importance to have at hand a correct topographical map of the area under investigation.GENERAL REMARKSThe actual amount of topographic detail shown will depend upon the money and time available for topographic surveying and upon the scale upon which the final map is to be produced...

Jan 1, 1912

By I. R. Muirhead

"One approach to making new technology available is to demonstrate its value under full-scale operating conditions. Studies were undertaken to assess the feasibility of this approach to introducing a longwall mining system to the western Canadian coalfields.The longwall method of mining coal is described, world and Canadian usage is reviewed, and the merits of the system in comparison 10 other coal mining methods are discussed.The rationale for a longwall demonstration in western Canada is presented, along with a proposed organization for the design, operation and dissemination of the findings from such a trial. The factors which must be considered in the design of the demonstration, and in the assessment of a potential site are highlighted. It is concluded that a demonstration of this technology is both timely and essential to prepare the way for the western Canadian coal industry of future prospects for coal.IntroductionFor many years CANMET has encouraged research work organized on a cooperative basis. This requires that a working consensus must be negotiated by researchers and operators at the beginning of the project and continuously refined as work proceeds. The result is usually a more relevant selection of research problems, improved direct ion and con duct of experiment al work and often a validation phase in which research concepts are tested in an opera ting environment. All this tends to narrow the gap between obtaining research results and applying them.Even under the best of circumstances cooperative projects require a good deal of coordination and enthusiasm to maintain focus and the pace of work. The working perspective of a research scientist in a government laboratory is substantially different from that of a mine operator at a producing mine, and a common ground must be found. This is difficult to do and cooperative projects typically evolve over several years as experimental results progressively define the potential solutions to mining problems."

Jan 1, 1985

By L. Tejeda, J. R. Donald, R. Parra, J. Duran, P. H. Lauzon

"Crucible slag tests were employed to evaluate different refractory brick classes for the Cerro Matoso electric furnace. Comprehensive analysis was conducted to evaluate the crucible erosion and characterize any slag/refractory reaction products.The classes of refractories investigated were:•,tar-impregnated magnesia;•,rebonded fused grain magnesia-chrome;•,direct bonded magnesia-chrome;•,alumina-chrome;•,picrochromite; and•,magnesia-alumina (spinel).It was concluded that tar-impregnated MgO bricks were the most suitable for the slag chemistry and furnace environment according to corrosion and infiltration resistance. A picrochromite (MgCr2O4) brick performed exceptionally well with regards to erosion resistance, however, the slag infiltrated extensively through the brick pores. Alumina-chrome, direct bonded magnesia-chromite, and spinel (magnesia-alumina) bricks were evaluated as not suitable for use in the furnace."

Jan 1, 1999

By J. B. Gwiazda

Maintenance of a constant load setting throughout longwall support units and selection of the proper initial bearing capacity depending on the type of roof strata are the basic factors that ensure good performance of roof support in a longwall. These requirements can only be met by hydraulic support. The greatest advantage of hydraulic support is achieved when uniform pressure is imposed on the roof throughout the length of the longwall. Such support, however, is provided only if each of the support units acts with the same force against the roof, i.e., has the same setting load. In such cases, the roof behaves like a uniform plate without bending and shearing stresses, thereby ensuring an undisturbed structure. Without a positive set value system, achieving an equal setting load for all units of the longwall support is impossible. Due to alterations of the feed line pressure of support units as well as some reasons related to man's psychology, operators extend the height at different setting loads. This produces nonuniform roof stress, and disturbs the structure. Consequently, the roof usually cracks. The author has developed a positive set value system, which is described in this Technical Note. Selection of the setting load Two pressure values in the feed lines are usually applied in longwall hydraulic systems. Lightweight support is fed by 25 MPa (250 bar) liquid, while heavy duty units receive a nominal pressure of 31.5 MPa (315 bar). Such pressure is required not only for the props but also to power the adjust¬ment jacks and the advancing ram. If the feed pressure is too low, there will be difficulty in shifting the unit despite the inversion system of the advancing rams. On the other hand, for many roof types, the feed pressure often appears to be too high when applied as the setting load pressure. An excessive setting load acts too strongly against the roof, crushing weak strata close to the roof. The author has recognized a case where an excessive setting load destroyed not only the nearby roof strata but also the strata above a 2-m (6.6-ft) sandstone layer. In addition, an excessive setting load relieves the side¬walls, increasing the resistance when using cutting machines. As a result, the yield of coarse coal is diminished, and increased fines dominate in the final product, lowering its economic value. As indicated, selection of the proper setting load, depend¬ing on the mining and geological conditions of the extracted seam, is extremely important. In some mines, measures applied to prevent disturbances include reduction of the feed line pressure by adjusting the feed pump valve. The disadvantage accompanying reduced feed line pressure is more difficult operation in advancing the ram. Due to the reduced feed line pressure, the force of the advancing ram is much lower than the designed value. Other designs suggest using a third feed line. However, installation of supplementary valves on the support units is required, a time-consuming and expensive procedure. The disadvantages of the powered supports are eliminated by a system designed by the author. So far, such a method of setting load control has not been used in any type of support. Setting load control unit The designed positive valve set for prop loading and the setting load control correspond to existing control systems for hydraulic powered support. The layout of the unit connected to the hydraulic prop control is presented in Fig. 1. The unit is marked LIDS. It incorporates three valves that may operate separately or connected. Valve A automatically opens and closes with liquid flow in the prop feed circuit. The valve is opened when the canopy touches the roof and closed when the support unit is withdrawn. Valve B serves as the setting load control. Valve C automatically opens and closes the flow in the line connecting the under-piston space of E to the prop F with the separator G. The valve block of each support prop is marked BZ. The UDS unit is connected by the hydraulic lines to the F prop control circuit. A valve is connected by H to pressure line J and by K to the G separator. In the UDS-3 version, line L is connected to M, linking the over-piston space of F prop with the G separator. Valve B is linked with valve A by a connector; it is also connected to the under-piston space E of prop F by line P. Valve C is fixed between lines K and P, connecting space E of prop F with the separator G. When setting the support, the liquid flows from line J through separator G, the BZ valve, and valve C to the space E of prop F. When reaching the roof with the canopy, valve A is opened and C closes. In this way it is impossible for the operator to cause the liquid pressure in space E of prop F to reach the level of line J. The prop pressure is set by valve B of the UDS unit. When withdrawing the support, valve C is automatically opened and A closed. Three UDS units have been fabricated and are designated

Jan 1, 1990

By Elard Miranda, Carlos Lopez

El éxito extractivo en el tratamiento de los minerales auríferos, depende fundamentalmente de su buena caracterización física y metalúrgica, de modo que para un determinado grado de liberación del mineral brinde información acerca de tamaño del elemento valioso y si este se encuentra liberado o incluido en alguna especie mineralógica; del mismo modo debe conocerse el tipo de elemento valioso, si es oro o electrum y los porcentajes de Plata que presenta este último.

Sep 1, 2017

This Association is made up of Alabama members of the following technical societies: The American Society of Civil Engineers, American Institute of Mining Engineers, American Society of Mechanical Engineers, American Institute of Electrical. Engineers, American Chemical Society and the American Institute of Architects. The association organized last winter for the purpose of maintaining an organization among the technical men of the State of Alabama, to stimulate the development of the natural resources of the State, to foster public interest in all things beneficial to the State, to advance the interest of the technical profession in the State and to encourage social intercourse among its members. On June 30, 1917, an excursion was made to the power house of the Alabama Power Co. at Lock 12 on the Coosa River. This is the first meeting held outside of Birmingham and is also the first meeting to which ladies were invited. About 85 members and guests attended and the excursion was voted a great success by all present.

Jan 8, 1917

By A L. Welsh, P S. Newling

Mill operators are entrusted to manage what are normally the largest capital assets on any mine site. Achieving maximum utilisation and lowest costs that drive operating margins are realised by applying well known fundamentals of good housekeeping and proactive (as opposed to reactive) maintenance programmes. Historically, maintenance and operations staff are bought in late during the construction stage and often do not have the time, know how or tools to put in place (let alone train the incumbent staff) a functioning maintenance system before commissioning starts. They then get drawn into a reactive maintenance paradigm as teething problems post commissioning are dealt with and day to day issues envelop the line tradesmen and supervisors. Additionally, even when some semblance of a planned maintenance system is established, it is often the case that over time personnel and cultural issues mask the development of problematic maintenance practices. As has been observed by the authors on many occasions, even when some basic programmed maintenance system is in place, the collection of maintenance data is often inaccurate, incomplete and not subject to analysis. The net result is of course a high incidence of machine failure leading to lower than expected availability, which ultimately translates to lower revenue and higher net maintenance costs. The time taken and the cost to repair a failed machine is always greater than the timely and planned repair of a worn machine.Upon review of a number of processing plants around the world, especially gold and small base metal operations, it is apparent that companies need to implement maintenance systems whereby the operators are not overwhelmed with data and can manage by exception. Inadequate or inaccurate data collection and analysis result in poor decisions being made and misguided actions taken. GR Engineering Services (GRES) has developed a system to enable the custodians of mining plant assets to make more effective and effective use of maintenance data by being able to focus on the indicators of plant deterioration and to programme concurrent maintenance activities to maximise plant availability and utilisation.This paper outlines the structures that can be employed to address the challenges of implementing a proactive asset management system. The best practice strategies described herein have been based on the fundamentals of a sound asset management framework:a phased approach to the development of Asset Management methodology and processeseffective implementation of programmed maintenance routinesmanaging asset condition data collected from various sourcesefficient analysis of asset data and management by exceptioninterfacing asset management data with Computerised Maintenance Management System (CMMS) and Electronic Management Systems (EMS) systemstips to assist with maximising asset performance.CITATION:Welsh, A L and Newling, P S, 2015. Operating strategies for custodians of company assets creating wealth, in Proceedings MetPlant 2015, pp 338–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By D. Koch

Bentonites and bentonite containing sealing materials are used since many years for sealing purposes in foundation, dike construction, hydraulic engineering and landfill construction, especially for encapsulation of old waste deposits In the near future compacted bentonites will be important components of multi-barrier systems for dry charge of old mines, for underground disposal of hazardous or radioactive wastes. Because of their exceptional physical, structural and chemical properties, bentonites are offering manifold possibilities to protect the environment against the negative effects of dumping grounds. Often the compliance with legal regulations for waste dumping or the isolation of contaminated areas is possible only by using bentonite containing sealing systems. The essential properties of bentonite, bentonite containing building materials and the different techniques of making horizontal technical base liners and vertical cut-off walls are explained. For horizontal technical base liners the adsorption ability, the ion exchange capacity and the swelling behavior of bentonites are important. For cut-off walls bentonite controls the rheological behavior of the slurry and is responsible for the low permeability of the hardened bentonite-cement-wall. In the multi-barrier systems of repositories for chemical or radioactive wastes compacted bentonites are considered to be favourable sealing and backfilling materials because of their high swelling capacity, their adsorption and ion-exchange ability and their plasticity in water saturated state.

Jan 1, 2005

By Joseph Hartshorne

Ever since the introduction of the Siemens regenerative furnace, it has been recognized that a certain amount of gas is lost each time the furnace-action is reversed. This loss comes, first, from the gas which passes through the free connection between the stack and the gas-main, which exists during the time the reversing-valve is turning over; and, secondly, from the gas which is in the chamber and flues, from the hearth to the reversing-valve, and which flows back into the stack when the valve is reversed. The amount lost each time is, of course, small; but, since a furnace is reversed from four to six times every hour for, say, 300 days in the year, the aggregate is large enough to be well worth attention. The estimate has been published1 that, in Germany aloue, the loss from the first of the above causes amounts to 500,000 barks per year. The loss from the second cause is, of course, much greater.

Jan 1, 1907

By Tong Gao, Jingyu Qin, Xiangfa Liu, Zengqiang Li, Yaoxian Zhang

"The recycling of aluminum materials is a green industry while Al–Si–Fe is a typical scrap aluminum alloy. The key point of recycling Al–Si–Fe alloys is to separate Al and Fe. A method by introducing Al–Si–Fe alloy into Mg melt has been investigated in this work. A separation layer with gathered Fe–rich and Al–poor Fe3Al0.7Si0.3particleswereobtained at the bottom of the cooled ingot, indicating that ß–Al5FeSi phase evolves to Fe3Al0.7Si0.3,and quantities of Al are released to the upper Mg matrix simultaneously. However, the evolution of Al3Fe by adding binary Al–Fe alloy into Mg melt is different. It is supposed that element Si plays an important role in the phase evolution procedure, thus affects the performance of this method.INTRODUCTIONThe rapid development of aeronautic, automotive and aerospace technologies strongly depends on the consumption of materials while sustainable development is the future direction. Aluminum is a recyclable material and Fe is one of the most common impurities. Fe can be introduced into Al alloys by adding low–purity alloying materials and by using unprotected ferrous crucible, tools, or equipment (Belov, Eskin, & Avxentieva, 2005; Lu& Dahle, 2005).For instance, wear–resistant rings are usually inserted into piston head when producing Al–Si pistons and an infiltration procedure by putting the cast iron rings into Al melt before casting is always essential. As a result, both the re–melting of pistons and the reuse of Al melt for infiltrating rings lead to the enrichment of Fe element, which can be even high to5 wt.%(Viala, Peronnet, Barbeau, Bosselet, & Bouix, 2002).It is widely known that coarse ß–Al5FeSi particles will form in high Fe–contained Al–Si–Fe alloys which is harmful for the mechanical properties. In the past decades, several methods to eliminate the harmful effect of ß–Al5FeSi have been investigated which can be widely referred (Munson, 1967; Lee, Kawamura, Inoue, Cho, & Masumoto, 1997; Suárez–Peña& Asensio–Lozano, 2006; Eidhed, 2008).These methods can be divided into two kinds. One is to aggregate and remove the Fe–rich phase through the methods of centrifugation, gravity filtration or magnetic separation. The other way is modifing the morphology of flake–like ß–Al5FeSi by overheating the melt or adding neutralized elements. However, these traditional methods are rarely used due to respective disadvantages, while the commonly used method in industries is using primary aluminum for dilution. However, only less than 30wt.% of scrap Al can be added into primary Al melt for each melting work while it also results in the decrease of product quality simultaneously(Zhang, Liu, & Liu, 2016)."

Jan 1, 2018

By M. W. Strong

THE technique of handling drilling muds varies somewhat, partly because of personal factors but mainly because of differences in forma-tion, the type of problems met with, and the general drilling conditions in different localities. The much greater depths to which bore holes are now carried have made necessary closer attention to and great modifications of all aspects of drilling-mud technique. Increased depth means smaller hole, smaller drill pipe, smaller clearances, higher pumping pressures, higher differen-tial pressures between shows and the mud column, less accurate control of the weight of the mud column, delayed receipt of formation data, and poorer samples. It means longer delays and greater hazards in rectifying mistakes or dealing with accidental occurrences. Equipment on a larger scale is necessary and more pains must be taken with layout. Lastly, the budget costs of raw materials have risen to high figures and economy of time and of direct monetary expenditure have come to mean much more than formerly. A mud laboratory is now part of the essential establishment of a modern oil field and to it current problems can be submitted for the most thorough investigation. The detailed chemical properties of all mate-rials purchased or quarried have to be investigated. Detailed data on the physical properties have to be ascertained and research on improve-ment of material and its most efficient use has to be carried out. In this paper we propose to discuss the main mud problems with which we have to deal in Iran, some of which are peculiar to our local conditions while others are of the general type common to all workers in this subject.

Jan 1, 1938

By N. K. Chen, R. Maddin, R. B. Pond

A METHOD has been described by Andrade' for obtaining very rapid grain growth so that single crystals of high melting point metals could be made with comparative ease. The furnace construction was essentially a very thin wire through which was passed an electrical current so that "a high uniform temperature" was maintained. The wire was surrounded by a fused quartz tube from which the air had been evacuated. Andrade applied this method to the growth of single-crystal wires of alpha iron, and Tsien and Chow2 prepared single crystals of molybdenum 0.25 mm diam in this way. In the present report a method is described in which the basic idea of the Andrade furnace is utilized. However, modifications are employed so that large single crystals of molybdenum or of any refractory metals can be grown. Furnace The modified Andrade furnace is shown in Fig. 1, and the detailed drawing of its construction can be seen in Fig. 2. The furnace proper consists of a 2'/2-in. diam fused silica tube, 20 in. long, which is evacuated continuously at the bottom. Two water-cooled copper electrodes hold the specimen by means of collets held in place in the electrodes by set screws. These electrodes serve also to transmit power to the specimen. The lower electrodes can be clamped to the stand, while the upper electrode is fastened in place to the bellows which in turn is further connected to one side of the lever arm, flexibly supported at the top. After the specimen is mo;nted- and the vacuum is secured, the lever arm is adjusted by means of the counter weight so

Jan 1, 1952