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By Feng Liu, Bingji Yan, Zhiwen Shi, Hongwei Guo, Jianliang Zhang

During production of a large quantity of steel, slag is produced at the same time. This paper chooses blast furnace slag (BFS) as the main material for the research. The purpose of the research is to explore its optimal physicochemical properties and the use of BFS in building stone field. The paper elaborates the experimentation process of producing glass-ceramics and presents the results. The results show that SiO2 content in BFS and amount of Cr2O3 and Fe2O3 added as nucleating agents have certain effect on the properties of glass-ceramics. The results also show that the exothermic peak temperature of base glass is the lowest when adding 20% SiO2 to the BFS, and 2% Cr2O3 and 3% Fe2O3 as nucleating agents, which makes easy crystallization and optimal properties of the glass-ceramics.

Jan 1, 2015

By Tatsuo Itou

Both sales volume of Aluminum Can and its recycling rate are remarkably increasing here in Japan. In 1993, recycled can volume was 11.78 billion cans ( 116,258 metric tons ) and its recycling rate 57.8 percent. We, MITSUBISHI MATERIALS CORPORATION. the leading manufacturer of aluminum can in Japan and our affiliated companies are very deeply involved in recycling used beverage cans ( U.B.C ) and recycling them back to can stock. In this paper. I would like to present the following; 1. Recent trend of beverage can consumption in Japan. 2. Trend of aluminum can and its recycling rate in Japan. 3. Future of aluminum can business in Japan.

Jan 1, 1995

By Rudolf E. Greuer

Introduction The Institution of Mining and Metallurgy and the Institution of Mining Engineers organized the Third International Mine Ventilation Congress held in Harrogate, England. Sixty-one papers were presented and about 300 participants registered. About 30% of the participants came from Great Britain, 20% from South Africa, and about 5% each came from Australia, Canada, China, France, US, and West Germany. The remainder of the participants came from 18 other countries. Eleven of the papers presented dealt with methane, three with diesel exhausts, four with dust, four with radioactivity, 18 with heat, and 15 dealt with main and auxiliary ventilation. Six of the papers dealt with mine fires, which is a boundary region between main ventilation and gas concerns. Ventilation Congress proceedings are available. See ME, December 1984, page 1687, New Books page. With CH4 and radioactivity topics, the Australians dominated since they are becoming large coal and uranium producers. With diesel exhausts, the most important problem in highly mechanized mines, the North Americans were prominent. The South Africans, working in 90% SiO2 in their gold deposits, were preeminent in presentations on dust. They also led in topics related to heat, joined by the West Germans whose mines are getting deeper. In main and auxiliary ventilation, Great Britain and West Germany provided the majority of contributions. Methane The large number of methods for the precalculation of CH4 liberation in longwall mining all contain three elements: gas content of the coal, gas emitting zone (or influence zone of face), and degree of gas emission. Determination of the gas content, commonly accomplished by taking coal samples, does not pose much difficulty. But this is not the case with the other two factors. Most existing approaches rely on rock mechanics observations. Some only rely on intuition or speculation. The West German coal mines conducted a large research project between 1977 and 1982, in which gas pressures around longwall faces were measured. Gas pressures and gas contents can be related. Therefore, influence zone and degree of gas emission can be determined simultaneously. The precalculation of CH4 liberation in room-and-pillar mining is simpler. Since foot and hanging walls remain essentially intact, gas pressure distribution and gas flow can be calculated using hydraulics equations. A key to these calculations is permeability. A group of Australian researchers reported that the permeabilities of rock under three dimensional stress differs from rock under destressed conditions. This fact was known, but no systematic observations existed. These were provided. Methane drainage has been practiced for more than 40 years. It is used with great success in longwall operations. Some of the West Germans think that methane drainage from the footwall is neglected. Under certain geological conditions, they claim this is as important as drainage from the hanging wall. A research project was presented in support of this claim. Considerable efforts have existed for more than 10 years to use methane drainage in room-and-pillar mining. A paper described the accomplishments of Consolidation Coal Co. Since coal and rock are not fractured as much as in longwall mining, gas transport takes place by the slow diffusion from micropores into the cleats. Then, it is transported by laminar flow along the cleats until a drainage borehole or the mine workings are reached. Boreholes about 300 m (1000 ft) long can reduce the gas content of a band of coal 100-m (330-ft) wide by 50% in one year. A paper from India described methane drainage from gob areas. A French paper reported that especially high methane concentrations can be drained from gob areas if the face ventilation is descensional. Methane buoyancy and ventilating pressures compensate each other, and little air dilution by leakage takes place. Another French paper described a newly developed gas and air velocity monitoring system making use of a microcomputer. Four papers on methane dealt with gas outbursts. Two Australian contributions described the problems encountered with CH,-CO2 mixtures and the attempts to solve them with drainage boreholes having 10 to 20-kPa (1.5 to 3-psi) suction pressures. A Hungarian paper described problems and attempts to reduce the risks of gas outbursts in Hungary. Prediction of gas outbursts in coal seams was the focus of an English paper. Observations show that they are frequent when coal, through its geological past, has become soft and brittle with a resulting increased desorption rate. An instrument for gravimetric de-

Jan 1, 1985

By Nicholas J. Grant, Klaus M. Zwilsky

EVER since the unusual high temperature creep resistance and structure stability of SAP (Sintered Aluminum Powder) and similar aluminum-alumina alloys were reported,'," there has been a need to determine whether other metal-metal oxide (or other hard stable particle) alloys, not so ideal as the Al-Al 2 O 3 system, would show similar high temperature strength and stability. Of the many possible methods of obtaining a metal-metal oxide alloy,a one that offers many practical and theoretical advantages is the simple mechanical blending of metal powders with hard stable particles, followed by pressing, sintering, and hot extruding. With this purpose in mind copper powder and silica and alumina were selected for experimentation because these materials are readily available, cheap, reliable, and lend themseives te the simplest processing and testing. Starting Materials—Two sizes of electrolytically deposited copper powders were used, a —200 mesh powder referred to as A powder in this investigation and a —325 mesh powder referred to as C powder. Silica was added in the form of pure Potter's flint from which a —10µ fraction had been separated. Alumina of the a variety was used in two size ranges. The first was a —10µ fraction separated from a coarser aggregate, the second a commercial product of 0.3µ average diam manufactured by Linde Air Products. Preparation of Powders—Five-hundred gram batches of A copper with 1, 3, and 10 volume pct of each of the three oxides mentioned above were prepared, as well as C copper containing 1, 3, and 10 volume pct of —lop silica. Powders were weighed out carefully and blended by ball milling in air for 24 hr. Since this treatment resulted in surface oxidation of the copper, the charge was hydrogen reduced at 260°C for 5 hr. The next step consisted of hydrostatically compacting the powder into a shape suitable for the required hot working. For this purpose a slug about 11/2 in. in diam and 31/2 in. in length was produced by placing the mixed powders into a rubber sleeve, holding in a perforated steel canister, and rubber stoppering at the ends; the assembly was then subjected to a hydrostatic pressure of 50,000 psi. The air was evacuated from the assembly prior to pressing in order to prevent

Jan 1, 1958

A series of physical tests have been conducted to determine the actual performance of bunton to shaft side wall connections typically used in new shaft construction in South Africa. The test set-up is described, together with the applied loading, which incorporates a cyclical load component and a quasi-static load component, in an attempt to simulate actual conditions in the shaft. The test results are given and it is shown that generally the performance is adequate, provided double-slotted holes are not used. Generally the fatigue performance is found to be good, with the only exception being cases where the bottom of the bunton is lower than the seating level for the bunton to side wall connection. Arising from the tests, typical design values of connection stiffness, strength and fatigue life are proposed and a design procedure including these three key aspects of connections is described.

Jan 1, 2005

By Jeff Ardron

Unlike the first predicted deep-sea mining (DSM) boom 35 years, the public response to the re-emergent possibility of DSM is this time round is not entirely optimistic, with serious economic, social, and environmental concerns being voiced. In the intervening years, the troubling notion of the ‘resource curse’ has been popularized, whereby the economies of developing nations rich in natural resources (agriculture, minerals, and fuels), paradoxically appear to fare more poorly than their brethren who have fewer such resources. There have been a variety of explanations and counter-arguments regarding why the resource curse occurs, including how it can be ‘escaped’, and even some disagreement on whether it in fact does occur. Nevertheless, many commentators appear to agree that that the quality of governance is strongly implicated in the socioeconomic success, or failure, of these resource-dependent nations, and could indeed be the deciding factor. Unlike nations with diversified economies, the majority of the income from natural resource economies, in the form of royalties and rents, flows through national government; hence, good governance and fiscal management is of particular concern.

Sep 1, 2014

By E. A. Holbrook

LOCAL yearly taxes levied on bituminous coal lands in Pennsylvania have become a cost of first importance to the coal industry of the State. In Pennsylvania there is no State tax on real estate, but local taxation of real estate furnishes the greater part of the revenue necessary for the small governmental unit, as counties, townships, boroughs, and local school, road, and poor districts. Coal in place in the ground, whether or not title thereto has been severed from ownership of the surface, is assessed as real estate and on its supposed sale or market value. There are eight classes of counties in Pennsylvania, based on population; in populous counties of the first, second and third class, assessments are made by a county board appointed by the county commissioners and are fairly uniform throughout the county. In counties of the fourth to the eighth classes inclusive, property assessments are made by property assessors elected by and for each township within a county. In these counties the board of county commissioners acts as a board of equalization and review to hear appeals. In most counties, therefore, where there is a large unmined reserve of coal, assessments on that coal vary for each township, irrespective of the fact that the coal bed is continuous under many townships.

Jan 1, 1933

By Eldon Keith Stanek

This annual report deals with four distinct tasks related to research on the safety and reliability of mine electrical power systems. Task one is to develop tests and the associated instrumentation to detect incipient faults on a mine or any low-voltage power system. Task two is a dual effort related to the digital prediction of electrical transients on mine power systems and laboratory testing of transient suppression devices. Task three is also a dual effort. This task consists of both theoretical and laboratory work to assess both the reliability and the fail-safe characteristics of several items of protective equipment used in mine power systems. Task four consists of an effort to use programmable calculators and/or computer terminals to check overcurrent protective device coordination.

Jan 1, 1976

By Charles B. Escapule

The first successful heap leach of silver ores in the State of Arizona has been under continuous operation since early 1976 at the State of Maine Mine, two miles southwest of Tombstone, Arizona. The silver produced from leaching old mine dumps at this property vas the first in the Tombstone mining district to achieve a 999+ purity. While cyanide leaching of silver and gold ores is a time-proven accepted practice, a relatively new method of treatment called "heap" leaching was employed. Heap leaching is a comparatively inexpensive fast way to recover precious metals from low grade material.

Jan 1, 1981

By Rossiter W. Raymond

BY the courtesy of Mr. Charles W. Jenks, of Boston, one of the owners of this interesting mine, I am enabled to lay before the Institute a suite of specimens, illustrating its peculiar formation and the paragenesis of mineral species which it presents; and a recent brief visit and rapid reconnoissance of the locality permit me to supplement this exhibition with a general description, based upon personal observation. The mine is situated upon the Culsagee Fork of the Tennessee River, in Macon County, North Carolina, a few miles from Franklin. The most practicable route by which it can at present be visited is by wagon (or preferably on horseback) from Seneca City, S. C., a station on the Charlotte and Atlanta Air Line Railroad. The itinerary is as follows: to Walhalla,* nine miles; Walhalla to Highlands, twenty-nine miles; Highlands to the Culsagee, fourteen miles. By passing the night at or near Highlands, the mine can be reached and examined and the return to Highlands made on the second day; and the round trip, if performed in the saddle, can be completed in three days from Seneca City. It is not easy, with due regard to steed and rider, to do it in less time. The rough and precipitous mountain roads do not permit rapid travel ; and the journey is at best a fatiguing one. But its slight hardships are overpaid by the stimulating effect of the climate and the great beauty of the scenery, both of which are destined to become more widely known than at present, to seekers for health and pleasure. Indeed the town of Highlands, already named, is almost entirely made up of northern immigrants, attracted by these advantages and by the inducement of cheap land for agriculture and stock-raising. The Culsagee or Sugartown fork of the Tennessee traverses the belt of ancient crystalline schists on the west flank of the Blue Ridge. This belt abounds in valuable minerals. Among those of the nonmetallic class may be mentioned graphite, soapstone, serpentine, ashes- * A branch or cross railroad is in operation as far as Walhalla ; but the single daily train runs at an hour not convenient for this expedition ; and Seneca City is probably the best starting-point. At all events, I obtained there an excellent mount for the trip.

Jan 1, 1879

By Theodore Simons

The rapid and comparatively recent development of flotation has opened so fascinating a field for study and research that the older processes of gravity concentration no longer receive the attention they deserve. The early work of Munroel and Richards12 and the more recent contributions by Clevenger and Coe,3 Laist and Wiggin,4 Ammon,5 Bardwell,6 Crowfoot,' and Hayden8 (to mention only some which have appeared in our own Transactions) and by Schu1z,9 have furnished so much data that to offer something new seems a difficult task. It is still possible, however, to present known facts from a different point of view, and, with this in mind, the writer has undertaken to express basic principles of gravity concentration in terms of simple mathematics and mechanics; the conclusions thus reached will be found to correspond, in general, with those obtained by experimental methods. Rittinger, in his classic Aufbereitungskunde (1867)) reached analogous conclusions by way of intricate higher mathematics, for which reason his interesting investigations have remained a sealed book to most of us. The writer hopes that a more elementary treatment of the subject, based in part on Rittinger's metheds, may arouse new interest in the study of basic principles.

Jan 1, 1923

By Theodore Simons

The rapid and comparatively recent development of flotation has opened so fascinating a field for study and research that the older processes of gravity concentration no longer receive the attention they deserve. The early work of Munroel and Richards12 and the more recent contributions by Clevenger and Coe,3 Laist and Wiggin,4 Ammon,5 Bardwell,6 Crowfoot,' and Hayden8 (to mention only some which have appeared in our own Transactions) and by Schu1z,9 have furnished so much data that to offer something new seems a difficult task. It is still possible, however, to present known facts from a different point of view, and, with this in mind, the writer has undertaken to express basic principles of gravity concentration in terms of simple mathematics and mechanics; the conclusions thus reached will be found to correspond, in general, with those obtained by experimental methods. Rittinger, in his classic Aufbereitungskunde (1867)) reached analogous conclusions by way of intricate higher mathematics, for which reason his interesting investigations have remained a sealed book to most of us. The writer hopes that a more elementary treatment of the subject, based in part on Rittinger's metheds, may arouse new interest in the study of basic principles.

Jan 1, 1923

By Jérôme Girard, Shiu Kam, Sue Longo

"Historically, tailings management in a northern climate has involved the deposition of tailings into the Tailings Management Area (TMA) as conventional slurry. This type of system is obviously viable but presents challenges that are difficult to manage as circumstances change over the life of mine. These issues can include:? Increases in mill throughput, and? Life of the TMA for the life of mine.This case study will present how thickened, high-density, non-segregating tailings are used as an alternative to conventional slurry disposal to achieve greater storage capacity and enhanced environmental performance for a gold tailings facility in a northern climate. This paper will focus on how this change in deposition strategy accommodated the increased throughput of the mill and the increased life of mine. Specifically, the paper will discuss the addition and integration of new processes to the exiting mill system to accommodate the tailings management issues. It will highlight the challenges from laboratory testing to pre-feasibility to the engineered design of the thickened tailings system implemented at Musselwhite Mine.BACKGROUNDGoldcorp Canada’s Musselwhite Mine, in Northwestern Ontario (120 km north of Pickle Lake), is an underground gold mining operation that began production in 1997. The current mill throughput is about 4000 tpd (1.4 Mtpa). Gold extraction is based on a CIP process with cyanide destruction.The existing tailings management area (TMA) is located about 2 km southwest of the mill complex. The TMA is contained by high ground to the north and to the west and flanged by a moraine ridge along the south side. A number of dams have been constructed along this ridge. The dams were first built in 1996 and subsequently raised in 2000 and again in 2005. Excess tailings pond water is discharged to a polishing pond then released to the environment via a wetland.The TMA was originally designed to contain 13.7 Mt of tailings under a ponded surface for closure. The water cover was to inhibit adverse long-term environmental effects because the tailings contain pyrrhotite and other sulphide-bearing minerals that are potentially acid generating. The design was modified during Stage 3 Construction in 2005 to expand the storage capacity to 17.3 Mt (Golder, 2005). As of end of 2009, over 16 Mt of tailings had been deposited in the TMA. The slurried tailings were historically deposited at 50% solids."

Jan 1, 2011

By W. T. Isbell

In the Parkes process of lead refining, after desilverization has been completed by means of the addition of zinc, there remains in the lead from 0.5 to 0.6 pct zinc. At this stage in the refining operations virtually all impurities are reduced to refined lead specifications except zinc and antimony. All excess copper, nickel and cobalt have been removed by the zinc additions. The silver remaining should not exceed 0.1 oz per ton. It then remains only to remove the zinc and antimony in order to produce refined lead. At the Herculaneum plant of the St. Joseph Lead Co., practice formerly was to complete the refining by means of oxidation in a reverberatory furnace. This process consisted of heating the lead to 1400O to 1500OF and allowing it to come in contact with excess air passing over the surface of the lead and periodically agitating the bath of lead with air. This procedure not only resulted in the loss of zinc but of a considerable quantity of lead converted to the oxide in the form of dross and fume. The fume, collected in the baghouse, together with the dross was returned to the blast furnace, thus adding appreciably to the circulating load on the blast furnace and refinery. In addition, operation and maintenance of the reverberatory furnace were expensive and required the performance of disagreeably hot and somewhat hazardous work. The process of dezincing with high vacuum was developed at this plant as a substitute for the oxidation process and finally led to lower operating costs, the practical elimination of dross and fume and the direct production of metallic zinc, which is very suitable for re-use in the desilverization process. Essentially this process consists of subjecting the lead to high vacuum, in a kettle provided with means for heating, a bell-shaped member open at the lower end so constructed that it can be immersed in the molten lead, and means for evacuating the interior of the bell and for sealing an agitator. Metallic zinc is thus produced and collects on the upper cooled part of the bell member. This metallic zinc is periodically removed and re-used in the desilverization process. The process is quite simple. It is conducted at a low temperature, thus permitting the use of iron equipment, and shows a material saving in refining costs over the old method. Equipment and Its Uses Degincing Machine.—The equipment employed in this process consists of a dezincing machine, a steel kettle of 120 tons capacity, a vacuum system and equipment for handling the dezincing machine (Fig 1). The dezincing machine consists of a compact assembly, suitable for handling with an overhead crane, consisting of a treating chamber and the agitating mechanism. Treating Chamber.—The treating chamber is a bell-shaped shell (4), similar in shape to a hemispherical kettle with a lid

Jan 1, 1949

By X. Louw

"This paper examines the change in surface properties of the Polyurea used on spirals at different operational times: unused spiral, 28 months in operation and 58 months in operation. This is being done to investigate the alleged statement that spirals have a decrease in spiral separation efficiency after a certain period of operational time. Observing the surface characteristics under 1.5x and 36x magnification it can be concluded that the surface roughness decreases with increased operational time. This may be explained by a decrease in air inclusions and streak lines as the spiral surface wears. Decreased surface roughness should in theory have a beneficial effect on spiral separation performance. This leads to the conclusion that if a decrease in spiral separation performance is observed after a certain period of operation, it can’t be attributed to the change in surface properties. Uneven wear of the spiral surface, material creep or application of force to the spiral will change the profile of the spiral and could cause an adverse effect on spiral separation performance. The metallurgical test work showed that the best results are obtained at 30 - 35% solids by mass in the spiral feed. The iron recovery was significantly higher in the new spiral in comparison to the 2012 and 2010 spirals. The mass yield to concentrate in the new spiral was approximately three times more than for the older spirals. In conclusion, the yield combined with the grade, which equals the recovery was the best for the new spiral.IntroductionAn investigation was launched to research the common belief that spirals experience a decrease in efficiency, and therefore recovery, after a certain period of operation (a period of seven years has been used in the industry). The properties of the spiral that may have an effect on the efficiency are:"

Jan 1, 2017

By A. L. Marshall, F. J Norton

The object of this investigation was to make a comprehensive study of the degassing of molybdenum in order to determine how rigorous a treatment was necessary to completely remove sorbed gases from molybdenum electrodes in vacuum tubes. Some work has also been done with tungsten, nickel, iron and carbon. As a logical development of this work it has been shown that the gas is present throughout the body of the metal and a study has been made of the solubility of nitrogen in molybdenum and tungsten and the rate, of diffusion of nitrogen through molybdenum has been calculated. Tests were made on molybdenum from all the commercial sources and no difference was discovered in the nature of the gases present, the amounts or the ease of removal. The reason for this was apparent when a study was made of the manner in which gases are absorbed by gas-free molybdenum. It is necessary to heat molybdenum to 1760°C. in a vacuum of the order of 0.001 micron for a time which varies lineally with the thickness, in order to obtain a condition in which no further gas is evolved by the sample. A sample so degassed can be handled and subsequently assembled in a tube and then degassed readily. The gases obtained from molybdenum are carbon monoxide and nitrogen, the nitrogen being the more difficult to remove. Apparatus and Technique The apparatus is shown in Figs. I and 2. It consisted of two units, a degassing system and an analytical system. Each had a bake-out oven, as shown surrounding the systems in the sketches. The system , will be traced, starting from the sample in the degassing system. A water-cooled quartz chamber surrounded the sample. The high-frequency coil, which heated the sample, extended only around this chamber and was cooled by an air blast. High-frequency power of 1800-meter wave length was obtained from a self-rectifying oscillator circuit with a maximum power input of 20 kw. A graded seal connected the quartz to the rest of the apparatus, which was of hard glass. The temperature of the molybdenum sample was observed by an optical pyrometer through an optical window about 40 cm. distant from the sample. Since the object viewed under these conditions was not a black body, true temperature was not observed, but the so-called "brightness temperature." The correction of this to true temperature is discussed in a later section. The apparatus was taken apart just above the graded seal; the quartz chamber was slipped off, washed with nitric acid, water and alcohol, and dried by an air stream. The old sample was removed by unscrewing the lower nut, and the new

Jan 1, 1944

By A. L. Marshall, F. J. Norton

The object of this investigation was to make a comprehensive study of the degassing of molybdenum in order to determine how rigorous a treatment was necessary to completely remove sorbed gases from molybdenum electrodes in vacuum tubes. Some work has also been done with tungsten, nickel, iron and carbon. As a logical development of this work it has been shown that the gas is present throughout the body of the metal and a study has been made of the solubility of nitrogen in molybdenum and tungsten and the rate, of diffusion of nitrogen through molybdenum has been calculated. Tests were made on molybdenum from all the commercial sources and no difference was discovered in the nature of the gases present, the amounts or the ease of removal. The reason for this was apparent when a study was made of the manner in which gases are absorbed by gas-free molybdenum. It is necessary to heat molybdenum to 1760°C. in a vacuum of the order of 0.001 micron for a time which varies lineally with the thickness, in order to obtain a condition in which no further gas is evolved by the sample. A sample so degassed can be handled and subsequently assembled in a tube and then degassed readily. The gases obtained from molybdenum are carbon monoxide and nitrogen, the nitrogen being the more difficult to remove. Apparatus and Technique The apparatus is shown in Figs. I and 2. It consisted of two units, a degassing system and an analytical system. Each had a bake-out oven, as shown surrounding the systems in the sketches. The system , will be traced, starting from the sample in the degassing system. A water-cooled quartz chamber surrounded the sample. The high-frequency coil, which heated the sample, extended only around this chamber and was cooled by an air blast. High-frequency power of 1800-meter wave length was obtained from a self-rectifying oscillator circuit with a maximum power input of 20 kw. A graded seal connected the quartz to the rest of the apparatus, which was of hard glass. The temperature of the molybdenum sample was observed by an optical pyrometer through an optical window about 40 cm. distant from the sample. Since the object viewed under these conditions was not a black body, true temperature was not observed, but the so-called "brightness temperature." The correction of this to true temperature is discussed in a later section. The apparatus was taken apart just above the graded seal; the quartz chamber was slipped off, washed with nitric acid, water and alcohol, and dried by an air stream. The old sample was removed by unscrewing the lower nut, and the new

Jan 1, 1944

By E de Villiers

Several methods exist by which the capacity of a dense media separation (DMS) plant can be improved: 1) Increase the feed rate in spite of efficiency 2) Replace with bigger equipment 3) Add whole new module 4) Replace total plant 5) Change over to four shift/ seven days per week roster 6) Replace with alternative process 7) Increase the availability and utilization Options 1 ? 6 have varying degrees of cost implications. The seventh option would seem to be the easiest. Normally it is also the function of the plant operating and maintenance team to maximize this. Usually higher operating and maintenance cost are associated with an increase in these parameters. A general principle that is applicable to plants and systems is that as the complexity increases, the total availability decreases. By simplifying the flow line it may be possible to reduce cost while at the same time increase the availability and utilization. The typical standard DMS flow line contains components that compensate for the variance in pump performance or for the inefficient recovery of ferrosilicon with additional equipment. Things have changed though: 1) Advanced electronic control and monitoring is possible 2) More efficient magnetic separators are available 3) New more user friendly densifiers are available ORIGINAL FLOW LINE In principle the process consists of four flow lines or streams 1) Ore flow ? the feed is divided into a waste and product stream by means of the separating vessel

Jan 1, 2006

By Veena Sahajwalla

The cupola furnace is a coke-fueled shaft furnace used as a primary melting unit in iron foundries. Control of chemical composition of the iron tapped from the cupola is a key factor in productivity and quality control. In an effort to develop a control model for the cupola, a fundamental approach based on physical and chemical principles has been taken to describe the melting process. The behavior of oxidation of the solid charge in the stack of the cupola has been studied. Sulfidation of the charge materials by sulfur-bearing components released to the furnace gases from the coke has been described. Carburization of metal droplets of iron and of steel in separate molten streams has been characterized. Finally, reactions with alloying elements in the hearth (well) of the furnace have been defined. These reactions have been described in a computer-implemented model developed to predict the composition of the iron tapped from the cupola. The model has utilized the thermodynamics and kinetics of the oxidation, sulfidation, and carburization reactions, including temperature and physical aspects, in the various zones of the melting unit. The model predictions have been compared favorably with operating results.

Jan 1, 1992

By W. J. Kingwell

Where the equipment, technique and materials are available for the construction of large diameter rock socketted piles, this is frequently the most economical and environmentally acceptable method of supporting very large concentrated foundation loads in geoglogically appropriate areas. This paper outlines the current approaches in Australia to design and installation of large diameter rock socketted piles. The equipment and procedures described generally reflect those developed or used by Vibro-Pile (Aust.), a company which, while installing the usual range of driven and bored piles, specializes in the design and construction of large diameter rock socketted piles and possesses special expertise in drilling in high strength rock. A high capacity crane attached drill for large diameter drilling in rock is briefly described. Discussed in detail are the construction techniques employed and structural and geomechanical design methods adopted.

Jan 1, 1989