Search Documents

By J. C. Gerdeen

A new analytical model for the shear stiffness at a joint of the fully-grouted resin roofbolt is developed using the Theory of Elasticity and an analogy to a beam on an elastic foundation, Gerdeen [2]. The model developed in this study treats the elastic foundation modulus of the resin as being composed of both an elastic rock and an elastic resin. All previous attempts have neglected the elasticity of the rock and treated only the resin. A three dimensional finite element model of the bolt-resin-rock system is developed also and comparisons are made between the predictions made by it and the analytical solution. It is found that the agreement between the two representations ranges between 1.2% and 10.5%, with the greater differences being observed for systems of very large or very small bolt diameters and resin annulus thicknesses. Since such configurations are not the rule in practice parameter studies are performed using the analytical solution with the finite element solution being used as a check. For a 0.75 in. bolt, a resin annulus thickness of 0.1375 in., a resin with E = 7 x 105 psi and -1) = 0.210, and a rock of modulus E = 6.8 x 106 psi and V = 0.159 the shear stiffness is found to be 1.220 x 106 lb,/in, from the analytical solution and 1.245 x 106 lb,/in, from the finite element model. Applying the finite element model to the problem of the axial stiffness of the fully-grouted resin roofbolt a value of 6.002 x 106 lb./in. is obtained which proves to be at least 50% higher than any of the now existing analytical predictions.

Jan 1, 1976

By Yoichi Takeda

Copper solubility in SiO2-CaO-FeOx slag equilibrated with copper matte in 10% SO2 atmosphere at 1573K was estimated. Essential parameters are activity coefficients of copper oxide and sulfide, oxygen and sulfur potentials and activity of copper in the slag-matte system. A large number of experiments provide proper parameters to calculate copper solubility in slag, A classical thcrmodynamic model postulating CuO0.5 and CuS0.5 moleculcs assists in estimating copper solubility in slag. Additions of Si02 and CaO reduce copper solubility almost in any condition. Copper loss, that is function copper solubility and slag volume, in the silica saturated SiO2-FeO. binary slag is minimally equilibrated with less than 66% copper matte while copper loss in the 50% FeO.-SiO2-CaO ternary slag saturated with 2CaOSiO2 is minimally equilibrated with over 66% copper matte. This slag composition has potential for continuous copper converting, direct copper production or high-grade matte production.

Jan 1, 2003

By G. W. Grove

The Joseph A. Holmes Safety Association acid the Holmes Association have fostered many chapters that have served as a medium in increasing safety in the mining industry. Details relating to the formation, operation, and achievements of the J. J. Forbes District. Council of the Holmes Safety Association, which operates in the Uniontown-Brownsville bituminous coal district of western Pennsylvania will be of interest to all who are striving to increase safety in mines, quarries, and in the oil fields. The Joseph A. Holmes Safety Association The Joseph A. Holmes, Safety Association' was organized in 1916 by 24 of the leading technical societies and mining organizations to perpetuate 'the memory of Dr. Joseph Austin Holmes, first Director of the United States Bureau of Mines.

Jan 1, 1929

By David White

Jan 1, 1925

By Parker A. J, Muir D. M

Solutions of acetonitrile in water dissolve water soluble copper(I) chloride. Removal of volatile acetonitrile from the resulting solutions, by distillation with low grade steam, precipitates pure copper(I) chloride. This is used to purify a crude copper chloride sublimate from the chlorination of nickel matte but is applicable to other sources of copper(I) chloride. The pure product can be converted to pure copper(I) oxide, copper(II) oxychloride or pure copper metal directly.

Jan 1, 1980

By E. Morrice

This report of the Federal Bureau of Mines presents a laboratory procedure, with the requisite equipment, for electrowinning ingot (liquid) cerium metal from a fused-fluoride bath, the metal purity being about 99.9 percent. Physicochemical studies, including bath properties and electrochemistry, are included, with a speculative model of the mechanisms involved. An historical review of the methods used for electrowinning misch metals and yttrim-group metals, as well as individual rare-earth metals, is presented. The electrolytic preparation of metal from fused salt and nonaqueous media is summarized, along with the unsuccessful attempts at depositing the metals from aqueous solutions.

Jan 1, 1961

By John Ralston

"Interfacial chemistry plays a pivotal role in bubble-particle capture, for it controls whether or not attachment occurs. Surface heterogeneity, degree of surface hydrophobicity, bubble nucleation and related phenomena influence the stability of the aqueous wetting film between a particle and an approaching bubble. The latter must be unstable if capture is to occur. Various techniques that may be used to quantify this interfacial, chemistry-dominated behaviour, are described.The efficient capture of specific particles by rising bubbles and the delicate control of interfacial chemistry that leads to selective capture are central issues in froth flotation. For efficient capture to occur between a particle and a bubble, they must undergo a close encounter, a collision process dominated by hydrodynamics. Should this encounter bring the particle and bubble within the range of attractive forces, the intervening liquid film between the bubble and the particle will drain, leading to a critical thickness at which rupture occurs. The liquid-vapour interface then retreats over the solid particle surface until a stable wetting perimeter is established. The particle and bubble are then joined after this attachment process. The particle may only be dislodged from this state if it is supplied with sufficient kinetic energy to exceed the detachment energy in this detachment process. These various events are now well documented and may be followed using high-speed videomicroscopy (Schulze, 1984; Nguyen et al., 2001).The process of collision can now be described quantitatively for single bubbles colliding with bubbles under various flow regimes (Dai et al., 1998) and appropriate scale up is possible for multiple bubble particle collisions occurring under turbulent conditions (Pyke et al., 2002). In this paper we will be concerned with the role of interfacial chemistry and how this influences the attachment process."

Jan 1, 2003

By Jian Wang, Hongyang Cao, Binxiu Wu, Junhong Li, Jimin Wang

"The enrichment and separation of scattered metal indium component in the pressure leaching solution with sulfuric acid from vacuum furnace germanium slag were studied by iron substitute and P204 extraction, which is supplied by shaoguan smelter. The experimental results show that the extracting power of P204 for indium from pressure leach solution is powerful. The optimal technological condition were the ratio of P204 and sulphonating serosene 3:7, phase ratio 1:3, solution pH 1.2, and extracting 5 minute. The enrichment indium solution of 21.7 g/L In at 95.2% recovery ratio was obtained by three-stage counter flow extraction and four- stage counter flow stripping.IntroductionScattered metals, such as Indium and germanium, were inriched as intermediate product or by-product during the metallurgy process of other non-ferrous metals, such as lead, zinc, copper and tin. For example, the indium and germanium were inriched in vacuum furnace germanium slag, which is the by-product of zinc vacuum distillation operation from hard zinc. It is difficult to recovery the indium from the vacuum furnace germanium slag, because the indium content is low, and the chemical composition and phase compositon were complex.Recovery indium from bearing indium zinc slag was researched extensively, such as pressure acid leaching, high temperature evaporation, solvent extraction method[l-7], acid leaching method has the advantages of high leaching rate, which can be separated hydrochloric acid, sulfuric acid and silicon fluoride acid systems. Solvent extraction method has the advantages of low production cost, fast reaction speed, high enrichment ratio, and simple operation."

Jan 1, 2013

ARIZONA Established July 10, 1915 ROBERT W. THOMAS. Chairman ROBERT W. HUGHES, Vice-Chairman HUBERT O. WOODS, Secretary-Treasurer American Smelting & Refining Co., Hayden, Ariz. LYLE BARKER M. G. FOWLER RICHARD BRITTAIN M: C. HENRIE B. S. BUTLER F. D. 1. HONEYMAN T. G. CHAPMAN J. E. LANNING C. H. COLE A. MENDELSOHN G. C. DAVIS BRENT N. RICHARD E. Ii. DENTZER C. F. WILLIS

Jan 1, 1943

By R. D. Lindsay

"Pamour Porcupine Mines, Limited is involved in the mining, milling and primary refining of various gold, gold - copper and refractory gold ores. Pamour operates five mines in the Porcupine Mining District of Ontario, and two 2,550 t/d milling facilities.Both metallurgical facilities use conventional cyanidation technology including zinc cementation for precipitation of gold and silver from solution. The precipitation process, as applied to clarified leach solutions (less than 1 ppm suspended solids) at Pamour is called the Merrill - Crowe process. Precipitates from both milling operations are treated at Pamour's Area Refinery. Schumacher precipitates, unlike Pamour No. 1, require an ''Acid Treatment Stage"" prior to refining to remove the high contained copper. This is accomplished by leaching the precipitates initiallv with sulphuric acid to remove zinc and then with sulphuric acid and manganese dioxide to dissolve copper. Refining procedures after ''Acid Treatment"" are essentially the same for both precipitates.The following considerations highlight the basic principals applied to refining cyanidation precipitates at Pamour, including:"

Jan 1, 1986

By T S. Giraudo

The Macraes Gold Project, operated by GRD Macraes Limited, engaged GRD Minproc Limited to assist with the evaluation of a pressure oxidation circuit, this being the key component of a recovery enhancement project. The initial study gave sufficient confidence in the process to enter into project execution. GRD Macraes Limited was the first company to license Newmont Mining Corporation's pressure oxidation technology, which aims to improve gold recovery from the carbonaceous sulfidic flotation concentrate. This paper outlines the fundamental chemistry of the process followed by a description of the plant that was ultimately installed. A summary of the commissioning is given together with an overview of the production results to date. The project ramp-up was rapid, with design temperature and throughput being achieved within days of hot commissioning. Gold recoveries have exceeded expectations, improving from around 70% prior to the installation of pressure oxidation to above 84%. The project has increased the nominal gold output at Macraes from 120,000 oz/y to 170,000 oz/y. On-going plant optimisation for process parameters is discussed, giving rise to flexibility in gold production, with key controlling parameters exceeding design.

Jan 1, 2000

By Edward H. Peplow

Mr. Chairman; honored guests; ladies and gentlemen: The subject assigned me today by your committee, according to the program, is "the mineral industry and the public land law I have preferred to title the talk, "you can't mine here", for that is the essence of the message we, as an industry, have been getting from so many agencies of the federal government for so long. And, unfortunately, we can expect to hear the same message even louder and clearer -- with increasing frequency in future, unless. Every segment of the industry devotes the necessary time, energy and creative thought to combat successfully the forces that are writing and broadcasting that message. I said that agencies of the federal government are sending the message --- and this, of course, is true, the forest service, for example, and some bureaus of the department of the interior as well as others have appeared in recent years to be abiding by a policy designed to block mineral entry to as much of the public lands as possible and to wipe out existing mining claims.

Jan 1, 1967

By G. E. Johnson

E. D. HYMAN*—How much sorting of scrap is done ? G. E. JOHNSON (author's reply)—We do practically no sorting. We charge "run of mine" scrap to the furnace. The unmeltables, mostly iron, are in such demand today that there is no difficulty in disposing of them. It may soon be desirable to sort out from the unmeltables as much of the brass as possible. J. J. BRUGMAN†—We have somewhat similar problems in the secondary aluminum business. What is your method of removing the unmelted material from the furnaces? Why have you such an apparently small space in which to charge your materials? Do you find that you have to seal that opening, or can you have it open and continuously charge at one end and pull out the other ? G. E. JOHNSON—Our means of melting scrap is efficient only to the extent that we use the waste heat from the vaporizing chamber to do the job. It is a batch process. We open the charge door and place the scrap on the hearth by hand shoveling. The door is then closed during the melting down period. After the melting is complete, the opposite door is opened and the unmeltables are raked out. The doors are approximately 3½ X 4½ ft and are not sealed during the process only closed. They are nominally tight. Some metal is oxidized in the process. We have visualized a means of conveying the materials through this melting unit with the metals that are melted trickling out during its travel. T. H. WELDON‡—Mr. Johnson, in line with the last question, is it necessary to seal the furnace between the melting down and the vaporizing unit, or have you got an inverted syphon in the bottom of the chamber? G. E. JOHNSON—That was one of the first things we encountered. We had to have a sealed opening, and it is a molten metal seal. You have indirectly asked me another question, which was: "Do you have to seal up the melting unit?" I would say we should exclude as much air as possible, although we are not too efficient in doing that. We allow the melting unit doors to be open when we charge and when we remove unmeltables. You can readily see that that would lead to the idea of having a controlled atmosphere in the melting unit, and I think this would do a more efficient job of melting the scrap. T. H. WELDON—How often do you charge the furnace? G. E. JOHNSON—We charge the melting unit, and rake out the unmeltables, about every hour. H. R. HANLEY*—Are any provisions made for controlling the rate of oxidation for the production of various size particles for certain characteristics of the zinc oxide product? G. E. JOHNSON—Yes, there are many. You are getting pretty much into the fine points of zinc oxide manufacture. Some of us still think we have something to learn about that. In general, this muffle furnace as I have described it to you produces a rounded particle of zinc oxide which is generally formed by a rapid oxidation of the zinc vapor, followed by rapid cooling. We have gone to the other extreme in some of our experiments. We have changed the furnace to produce a type of zinc oxide, such as we thought was peculiar to American process zinc oxide, by controlling the temperature at the point of oxidation and maintaining that temperature for a much longer period of time than we do when we make the rounded shape. There are other relationships that this furnace readily provides. One of the important factors is the ratio of air to zinc vapors. We can vary that by varying the air supply to the baghouse, or vary the rate at which we are vaporizing the zinc by the simple expedient of regulating the temperature over the carborundum arch. We have a number of variables that permit us to produce all of the grades of French process zinc oxide from lead-free up through the highest grades of seal oxides. There are many controls that we can apply to the operation. What I have said is but a brief condensation. K. MORGAN*—Can Mr. Johnson give us some idea of the fuel consumption of the furnace ? How much oil does he use per ton of zinc distilled? I am also interested to know what sort of heat transmission he gets through the arch? What is the thickness of the tiles used to construct the arch? Some time ago we built a small furnace for a different purpose, using a carborundum arch, and we found that the reflectivity of the molten zinc surface was so great we had to use a very high arch temperature. We found we made an improvement by having a layer of carbon on the surface of the zinc. Has Mr. Johnson had any experience on these points ? Does he make any sort of insolu-bles which he leaves in the furnace which he cannot tap out ? G. E. JOHNSON—I believe your first question was the fuel consumption. If I recall, somewhere in this paper there is a test that I quote. I believe we used 800 gal in a given period of time. Offhand I cannot translate that into tons of metal. I might also state that we have this understanding; that the carborundum arch, as the temperature becomes higher, becomes more efficient in heat transmission. As a matter of fact, I believe it is at about 2600°F or higher that the highest efficiency of heat transmission becomes available. We have calculations that I cannot quote from memory which indicate that the carborundum arch does a really very fine job for this type of furnace. Another point that we had considered was the fact that this furnace could be readily constructed so as to furnish an ideal source of heat for waste heat boilers. If a carborundum arch was used over the melting unit, we would have no zinc vapors in the gases at all— just clean combustion gases from which we would have removed some of the heat. L. P. DAVIDSON†— The insolubles

Jan 1, 1950

By Lloyd F. Dunham

"Crucial to the implementation of new computer-based information systems at Sudbury Operations of Falconbridge Limited was a data communications network that would take computing power to the various mine and plant sites. Falconbridge required a capability to provide on-line data entry, inquiry, and reporting capabilities in three geographical areas, six mines, two mills, a smelter, approximately fifty shops, seven warehouses and numerous administrative offices throughout the Sudbury basin.Conventional cabling methods were rejected based on the projected cost of installation of necessary cables; lack of flexibility to meet the changing requirements of the mine environment; and the risk of losing service to an entire area depending on solitary communication lines.Instead, Falconbridge selected and installed a Data Carrier System (DCS) and Packet Switching Communication System from Teltone Limited, Markham, Ontario. This combined system ""piggy-backs"" computer data over voice-grade twisted pair wire, bringing data to the associated PBX equipment. From there data packets are assembled and routed to the central computer site where they are disassembled for entry into the host machine.Falconbridge has been successful in using existing technology to solve communications problems in a difficult environment. Plans for the future of this network will increase its utilization for technical and real time data communications in addition to the business systems workload it now handles. The Computer Services group in Sudbury is confident that the data highway will handle communications traffic well into the future.IntroductionIn late 1984, the Sudbury Operations of Falconbridge Limited undertook a review of their existing business computer systems. The results of this review indicated that there was an opportunity to improve the timeliness and quality of information coming from the existing computer-based systems while achieving an investment payback by undertaking the project. The greatest benefits from this project would be achieved if the computing tools could be delivered to the employees that were the day-to-day users of the data. Falconbridge's existing business systems were oriented to the batch mode of processing. An alternative solution to using the existing programs had to be found."

Jan 1, 1988

By Dyego Irineu Silva de Almeida

O presente trabalho foi proposto em sala de aula, na disciplina de tratamento térmico de ligas metálicas, do curso de Engenharia Metalúrgica da Universidade Federal do Ceará e teve como objetivo comparar as diferenças entre microestruturas e propriedades de um aço SAE 1016 após os tratamentos térmicos de normalização, têmpera e têmpera intercrítica. Três amostras do mesmo material foram tratadas termicamente. Uma amostra foi normalizada, outra temperada e outra temperada na zona intercrítica e após as análises metalográficas e ensaios de dureza foi possível concluir que a amostra normalizada apresentou uma microestrutura ferrítica com ilhas de perlita, a amostra temperada a 930ºC apresentou microestrutura martensítica e a amostra temperada na zona intercrítica formou microestrutura bainítica em uma matriz ferrítica.

Oct 30, 2017

By Leon J. Perrier

The paper describes the equipment in use, haulage grades, road conditions, tire sizes, tire performance and related problems. Various types of failures and causes, corrective action taken, tire records and reporting for control are also discussed.

Jan 1, 1977

By Beatryz C. Mendes, Igor K. R. Andrade, Roseli O. G. Martins, Gustavo H. Nalon, Rita de C. S. S. Alvarenga, Leonardo G. Pedroti, Carol F. R. Santos, Marcelo A. Alves

This work presents an experimental investigation of the influence of concrete blocks and mortar’s compressive strength on the flexural bond strength, normal to the bed joints, of concrete structural masonry. Third-point beam tests were performed on concrete prisms, considering two different kinds of concrete blocks (compressive strength of 5.9 and 8.2 MPa) and six different cement-lime mortar compositions (compressive strength around 30, 70, and 120% of the blocks’ net area compressive strength). Units’ absorption and mortar’s initial flow and water retentivity were not varied, but remained within the suitable range for use in structural masonry. For both types of concrete blocks, it was observed an increase on the prism’s flexural bond strength with the increase of the mortars’ compressive strength. A lower mortar’s water-cement ratio led to higher bond strength. When fixing the ratio between mortar’s and concrete block’s compressive strength, it was noticed that the increase on the blocks’ strength contributed to a slight increase on the masonry’s flexural bond strength, except when using high strength mortar, in which the increase was significantly greater.

Mar 1, 2018

By D. L. McCain

The movement of solids by pipeline is an art dating back well over 100 years as evidenced by many references in the literature. Even though all of the early pipeline transport systems were based on trial and error and relied mainly upon the designer's experience, hydraulic transport offered distinct advantages in convenience or cost for the chemical, mining, and civil engineering industries. It became well established for in-plant process lines, dredging, waste disposal, and other uses almost exclusively for short distances. During more recent times, much research work has been done in an attempt to understand the underlying principles involved in transporting solids in a fluid. Design criteria for pumping slurries have evolved to the point where pipelines designed for distances of several miles to several hundred miles can be accomplished successfully. Consolidation Coal Company designed and built a 10-inch diameter 108-mile long line1 for transporting coal in the 1950's and operated it from 1957 to 1963 when it was placed in mothballs because of falling freight rates for rail shipment. More recently, the 273-mile Black Mesa Pipeline2 was built and is operating. There are other examples of long distance pipelines,3 but all are for specially prepared fine slurries which allow the pipeline to be operated more economically.

Jan 1, 1975

By J. D. Braun, C. W. Powell

Diffusion between gold and indium at two temperatures below the melting point of indium (155.4oC) was investigated. The major, component of the diffusion zone was determined to be AuIn2; the other, intermediate phases in the system occur in much narrower layers In order of decreasing layer width these are: Au9In4, AuIn, Au4In. Inter diffusion coefficients of the four intermediate phases and the terminal solid solutions lie in the range of 2.4 x 10-l3 to 1.8 x 10-11 sq cm per sec. WHEN two metals which do not form a continuous series of solid solutions interdiffuse, each phase in equilibrium at the diffusion temperature should appear as a separate layer in the diffusion zone. In the Au-In system, diffusion plays a significant part in many commercial applications, particularly where indium alloys are used as solders for electrical contacts with very fine gold wire, for estab- lishing electrical contact to thin metallic films, and for mounting metal-coated piezoelectric crystals. A knowledge of the number, extent, and type of phases which form at diffusion temperatures below the melting point of indium, 155.4oC,1 and the diffusion constants for the system would be useful for these practical applications. Of more basic significance, additional information on polyphase diffusion in a system not previously investigated would be gained. The phase relationships in the Au-In system were determined primarily by Kubaschewski and Weibke1 and are based on thermal, microscopic, and X-ray analysis, Fig. 1. There are five intermediate phases in the system having approximate compositions corresponding to the formulas: Au4ln (ß)—80.0 at. pet Au; Au3In (?)— 75.0 at. pet Au; Au9In4 (d)—69.2 at. pet Au; AuIn—50.0 at. pet Au; AuIn2—33.3 at. pet Au. Solid solubility of indium in gold at 700°C is reported as 12.64 at. pet and at 406°C as 10.36 at. pet. No solid solubility of gold in indium is reported.

Jan 1, 1964

By AIME AIME

TWO days of solid discussion, with barely time out for meals, characterized the Tulsa meeting of the Petroleum Division. It was preeminently an earnest gathering devoted to technical matters. Sessions were held in the Crystal room of the Mayo Hotel with luncheon served each day in the back of the same room so that talk of methods, while slightly less formal, extended right through the lunch hour. Thursday evening the Committee did provide a little relaxation in an informal dinner at the Tulsa Club where, after a brief musical program and an amusing skit by the local Herman the Great, brief addresses in non-technical vein were made by President Farish and Vice-president Rice of the Humble Company, Henry L. Doherty of Cities Service, Secretary. Bain of the Institute, and others. The presence of leading executives of a number of the oil companies at the dinner and the sessions, and the cordial approval they expressed of the work of the Division were especially gratifying. The total registration was 215 with 100 at the dinner and 70-to 80 lunching together each day.

Jan 1, 1930