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By L. R. Burdick, R. Wiggers, J. F. Berkley

"INTRODUCTION On February 23, 1944, Solid Fuels Administrator Harold L. Ickes stated that the existing fuel shortage made it necessary to utilize a great surplus of freshly mined anthracite ranging in size from Barley (No. 3 Buckwheat) downward through the smaller sizes. As a part of the program to increase the use of such coal, field trials of mixtures of bituminous slack coal and anthracite Barley were made on industrial-size stokers at many fuel-burning plants. The following covers the test information it was possible to accu-mulate during the work of initiating the use of these mixtures at the plants.SUMMARY AND CONCLUSIONSField tests of various mixtures of bituminous slack coal and anthracite Barley on industrial-type stokers show that the use of such mixtures is very practicable and that it is possible to change and usually to adjust to an improved condition the characteristics of a fuel bed of eastern bituminous slack coal by the addition of proper amounts of anthracite. The improved uniformity of the fuel bed of single-retort stokers makes possible less manual attention to the bed. Air flow through the fuel bed is affected.Smoke is decreased. In general, the fly ash and also the unburned combustible in the fly ash and refuse are increased. Clinkering in the fuel bed is generally lessened. The peak-load carrying capacity of the stoker is definitely affected, usually adversely for the higher percentages of anthracite."

May 1, 1946

By R. M. Scafe

Although hydrogen has been intensively studied in its relation to steel quality, the methods of sampling and determinations are still open to question. It is true that various procedures have been proposed but actually there has not been sufficient agreement to establish a common base from which to work. As a result, it is difficult, to say the least, to correlate the reported results of some of the investigators in this field. The present symposium, premised on methods rather than effects, should prove of considerable value. For the purpose of this discussion two methods of sampling and analysis will be considered. First, sampling of molten steel in the ingot mold by use of an evacuated tube and cylinder using conventional methods of analysis for the gases collected; second, analysis by vacuum extraction involving the use of heating equipment and the determination of the amount of hydrogen evolved from solid steel samples by measurement at reduced pressures. Both methods have been used at Duquesne Steel Works and it is believed that either may be used with considerable benefit if the limitations of each method are recognized. Evacuated Tube and Cylinder Sampling devices for gases in molten steel suggested by various investigators range from very cumbersome and complicated devices to the relatively simple evacuated tube and cylinder used by Soler for deter- mining the CO content of the bath. This latter device was adopted (Fig. I) and modified to meet conditions at Duquesne Works. The principal modifications were in placing the cylinder at the side of the tube and the use of a sleeve on the immersion end of the tube. The first modification was made so that the cylinder could be readily detached and taken to the laboratory; the second, because of the difficulty encountered in obtaining an airtight seal after sampling and because of our practice of re-using the tube. Rigid control of the method of sampling and of the handling of the sample according to plan are of primary importance in hydrogen determinations. This applies to both the sampling of molten steel and the determination of the hydrogen content of cold steel samples. Except for a few preliminary samples taken from spoons, all work on molten steels using the evacuated tube was confined to the sampling and analysis of molten steel during the pour. As mentioned, uniformity of sampling was a basic consideration. As a result, every effort was made to follow definite sampling techniques and procedures. These included control of the depth below the surface from which the sample was taken, the timing between the shutoff and taking of the sample, as well as maintenance and care of the equipment. The distance below the surface at which the sample was taken was readily controlled bv means of a crosspiece and centering device attached to the tube. The steel was poured into the mold to the hot-top junction, the tube was then lowered into the 75

Jan 1, 1945

By D. Nie, M. Ren, T. Mo

This paper studied the phenomenon of room temperature creep deformation at crack tip and its effect on fatigue crack growth rate of a X-70 pipeline steel using compact-tension (CT) specimen on a MTS 810 testing machine. Time-dependent deformation at the crack tip under constant load was observed in this steel at room temperature and the amount of deformation produced was seen to depend on loading rate and the magnitude of stress intensity factor. It is found that there exists a critical stress intensity factor below which the deformation decreases with time when the applied load remains constant. It is also found that the occurrence of room temperature creep obviously affects the subsequent fatigue crack growth rate. The observed behavior was explained based on dislocation theory.

Jan 1, 2005

By Albert E. Ketler

Introduction – The introduction of computerized monitoring and control (M/c) equipment into the U.S. coal mining industry may prove to be of truly revolutionary proportions in the 801s.Many of you are aware that the British have developed and have been using such sophisticated M/C equipment for performing production and safety related tasks in their coal mines for nearly a decade. The benefits of M/C systems in the mining industry are usually separated into those which improve productivity, and hence make money for the company, and those which improve safety, and hence cost money. The economic benefits of M/C are startling for the production related functions such as for monitoring and controlling conveyor belts, de-watering pumps, electrical power distribution, and the like. It doesn't take much analysis to show that hundreds and even thousands of tons of coal don't get mined every time a belt shuts down or when power is out due to circuit breakers tripping for any number of reasons. A flood, caused by a malfunctioning pump which goes undetected for lack of feedback monitoring of pumping parameters, can destroy literally millions of dollars worth of mining equipment. The M/C system would be justified or not based on whether or not the productivity benefits balanced the cost within a timespan commensurate with the return on capital philosophy of the company. The safety related benefits are easily underestimated or ignored completely and the purpose of this paper is to under-score some of these benefits, as well as to review the application of M/C to the coal mining industry. The companies involved are Transmitton Ltd of England and Minetics Corp of Pittsburgh, Pennsylvania. Transmitton is probably the most experienced manufacturer of M/C equipment in the world having some 200 installations to its credit. Minetics is the marketing and manufacturing arm for Transmitton in the U.S.A. and is responsible for all aspects of distribution and service. Plans are underway for manufacturing of the Transmitton hardware for U.S. sales to be transplanted into U.S. subcontractors by 1981. Thus our coal mining industry will benefit from British technology, but without the delays and additional costs usually involved in international shipments.

Jan 1, 1981

By Hai Rong

EH-4 Electrical conductivity imaging system has been playing an important role in prospecting, looking for water resource, and determining coal mine gob boundary by virtue of its significant advantages such as collection of large volume of data, light weight, fast analysis, high-precision, and low cost. However, it has little application in determining the overburden failure zone and development of water flowing fractured zone and bed separation space in complex extra thick coal seam conditions. In order to confirm the overburden failure range and evolution of water flowing fractured zone and bed separations in complex extra thick coal seam conditions the panel 63005 of Laohutai coal mine in China was selected for study in this paper,. EH-4 magnetotelluric method was used to determine the overburden failure zones and bed separations in the overburden. Theoretical analysis and numerical simulation were employed to verify the EH4 survey results. The results show that the failure height in the overburden of the three coal splits was 120m to 170m before panel mining, and increased to 150m to 220m after panel mining. The overburden failure height was on average 7.4 times the equivalent mining height in complex extra thick coal seam condition of Laohutai coal mine when the sand backfilling and fully mechanized top coal caving methods were employed. After mining of panel 63005 started, bed separations were found on the hanging wall and footwall of the F18 fault where water bodies existed. The results obtained in this research not only provide a theoretical guidance for safe mining at Laohutai coal mine but also serve as a reference for predicting and preventing water inrush accidents for coal mines under similar condition in China.

Jan 1, 2014

By Ludmila Vieira da Silva Matos

O presente artigo investigou como a condição de operação das zonas de resfriamento em máquina de lingotamento de placas contribui para o desempenho de lanças air mist. Tal investigação foi realizada no laboratório da Spraying Systems Brasil a partir das premissas de projeto de uma nova máquina de lingotamento e um novo conceito de lança air mist: menor consumo de ar comprimido, amplo turndown e qualidade de cobertura por toda a curva de operação do resfriamento. As curvas de performance foram montadas para diferentes condições de utilização de ar comprimido: de 1,5 a 4,5bar de pressão constante. Cada lança teve das vazões mínimas às máximas de água ensaiadas. A qualidade do perfil do jato produzido foi verificada para cada ponto das curvas obtidas, em mesa de distribuição no laboratório da Spraying Systems. Com as imagens em mãos, foi possível selecionar aquelas condições de vazão de água e pressão de ar comprimido com melhores perfis de jato e cobertura. Como resultado, a fabricante da máquina pode validar e/ou modificar a curva de trabalho de resfriamento da máquina e garantir as melhores condições do perfil do jato e uniformidade de resfriamento.

Oct 1, 2019

By Chris Larsen, Ian Orford, Marilene Renaud, Mike Cooper, Lud Strah

"An AG/SAG mill was commissioned at the Brunswick Mine concentrator in October 1998. This paper discusses the original liner design for the bi-directional AG/SAG mill, observed liner wear, subsequent liner design modifications, and benefits. The mill liners consist of steel top hat shell liners, steel end liners, rubber grates and rubber lined pulp lifters.Lifter profile and plate thickness measurements were made on monthly shop days. Trends of wear rates were used to project when liners required replacement. Wear profile information was also used to determine where liner re-design would improve wear life or minimize scrap loss. Charge motion simulation modeling was used as a tool to assist liner design modifications.INTRODUCTIONThe Noranda Inc. Brunswick Mine, located near Bathurst, New Brunswick, is a large underground lead/zinc mine with a nominal production rate of 10,000 tonnes per day. The Brunswick concentrator commenced operation in 1964 with conventional surface crushing followed by rod and ball milling to reduce run of mine ore to the required size to feed two parallel flotation circuits. In 1998 the AG (autogenous grinding) mill was commissioned for a nominal production rate of 9,000 tonnes per day replacing two surface crushing plants, three rod mills and three primary ball mills. In May of 1999 the mining rate was increased and the service of the AG mill was changed to a SAG (semi-autogenous grinding) mill with the addition of 4 inch steel balls (4% volume). The mill operates in closed circuit with 0.66 meter horizontal cyclones to produce a ground product of 90 micron nominal size (K80).The AG/SAG mill liners are steel (Norsteel, chrome-moly steel) with rubber grates and rubber lined pulp lifters.The original liner design was based on studying other AG/SAG mills and recommendations by the liner supplier, Norcast. Design factors taken into account were total cost of lining (including material and labour), protection of mill shell and impact on operating performance."

Jan 1, 2003

Since 1955 Gaspe Mines has produced 144 million tonnes of ore, averaging 0.87% Cu, mined from two open pits and underground workings. In 1994, four exploration drill holes discovered a buried porphyry/skarn Cu-Mo deposit at depths of between 1000 m and 1700 m below the top of Porphyry Mountain. The mineralization and alteration associated with the Porphyry mountain quartz monzonite does not outcrop. A total of 19,500 m of drilling in 12 drill holes has outlined 200 million tonnes grading 0.73% Cu and 0.08% Mo. Mineralization occurs as veins and disseminations of chalcopyrite and molybdenite. Drilling and feasibility studies continue.

Jan 1, 1998

By H. R. Quina

Phosphate is one of the most important minerals in our world today. It contains the life-giving element of phosphorus, which is essential to the growth of every living cell in plant, animal, and man. This vital mineral is found in twenty-three states of the United States; however, for more than 70 years, Florida has led the nation in phosphate-production and now produces 70% of the requirements of this country. Since the early 1880% when rich phosphate deposits were accidentally discovered in a river-bed in Central Florida, the industry has developed into a multi-million-dollar operation. Phosphate mining began in Florida in 1887 with very crude methods and equipment. The original process was necessarily slow and tedious, resulting in total production of 3000 tons in 1888. Progress was made in improved mining operations, and by 1894. Florida had grabbed the lead as the nation?s largest phosphate-producing area, and is still in the top position.

Jan 1, 1962

By Donald F. Kennedy

During the past several years Climax Molybdenum Co. has been engaged in testing various types and sizes of hollow drill steel. The majority of tests have been on 7/8-in. hexagon st.ee1, inasmuch as it represents approximately 70% of total drill steel consumption at the Climax operation. Prior to December 1960, tests on 7/8-in. hexagon drill steel were conducted on steel with a forged collar and, in most cases, with a threaded bit connection. Through these tests and research, some improvement in steel life was achieved by making changes in heat treatment, design and alloying constituents. However, during that month, research and testing commenced on a rubber collar which was designed to replace the forged collar on 7/8-in. hexagon drill steel. Manufactured by the LeRoi Div. of Westinghouse Air Brake Co.. the collar. is very simple in design, consisting of a 1 ½ -in. diam steel cylindrical sleeve 2 in. long, containing a bonded rubber insert and attached to the steel with an epoxy cement

Jan 8, 1962

By George P. Demopoulos, Yan Zeng, Zhibao Li

Precipitated silica is marketed with a rising demand as reinforcing filler in the rubber industry and as a potential raw material for the synthesis of lithium-ion battery electrodes. Due to an awareness of the environmental impact of the existing processes for the production of precipitated silica, a green and sustainable process was proposed by using sodium bicarbonate (NaHCO3) as an alternative to sulfuric or hydrochloric acid in the precipitation reaction with sodium silicates. The use of NaHCO3 allows for better control of the supersaturation and pH to form silica with desired quality. Additionally, Na2CO3 solution as the process by-product is recyclable because it could be recovered to produce NaHCO3 by absorbing CO2. The solubility of sodium metasilicate nonahydrate (Na2SiO3·9H2O) in the Na-CO3-HCO3-OH-H2O system was measured using a dynamic method in the temperature range from 288.15 to 308.15 K. It is found that the solubility of Na2SiO3·9H2O decreases with increasing concentration of either Na2CO3 or NaOH over the investigated concentration range. With the aid of the OLI platform, a chemical model for the Na2SiO3-Na-CO3-HCO3-OH system was established with newly obtained interaction parameters of the Bromley-Zemaitis model by regression of experimental solubility data. The new model predicted the solubility of Na2SiO3·9H2O in multi-component systems with good agreement and was used to conduct a preliminary feasibility study of the new process.

Jan 1, 2015

By Pervez Patel, Martin G. Frohberg, Demetrios Papamantellos

Model experiments were carried out on the mass transfer of iodine between n-hexane and a 4 2 X 10-3 M aqueous sodium hydroxide solution. The influence of mechanical stirring by means of small gas bubbles (ca. 0.01 ml in volume) on mass transfer was examined in independent experiments. The results were described with the help of the penetration theory and in the case of bubble stirring with the help of a mathematical model based on this theory. S LAG-METAL reactions, especially those in steel-making processes, often occur under conditions where gas is evolved in the form of bubbles that break through the slag-metal interface. It is known that stirring by means of bubbles increases the mass transfer coefficient, but there has been very little quantitative work done in this field. Because of the difficulties that attach to experimental work at high temperatures this study was confined to model experiments at room temperature. EXPERIMENTAL APPARATUS The transport of iodine from an n-hexane layer into a weak sodium hydroxide solution was studied a) with stirring by means of bubbles and b) with mechanical stirring. The apparatus for the experiments with bubbles consisted of the cell, two Dreschel bottles filled with hexane in order to saturate the nitrogen flow, one flow meter, and a nitrogen gas cylinder fitted with a fine-regulating valve. Fig. 1 shows the cell consisting of a glass cylinder 33 cm in height with an overall diameter of 7.5 cm embedded in a copper flange. The flange is connected to a Plexiglas plate and to the gas inlet. The Plexiglas plate has holes of 0.2 mm diam bored into it which are spaced 1 cm from each other. For the experiments with mechanical stirring the bottom of the cell was sealed off by a Plexiglas plate. The upper layer was stirred by means of a glass stir-rer and the bottom layer with the help of a magnetic stirrer in a counter rotatory direction. Both stirrer speeds could be varied continuously. EXPERIMENTAL PROCEDURE Iodine dissolves in n-hexane producing a stable violet color thus enabling the iodine concentration in

Jan 1, 1970

By R. G. Reddy

The Margules .equation is used for interpreting excess Gibbs energy of several ternary systems. In the present study activity coefficient of 'a dilute solute, 2, in a binary solvent 1-3 was derived. The derived expression is used to interpret logarithmic activity coefficient of oxygen and sulfur in several metallic systems. Self interaction parameter of the solute is derived from the partial function of solute using constant compositional path. An expression for logarithmic activity coefficient and self - interaction parameter of solute is also derived using Maclaurin infinite series. The derived equation is based on Maclaurin infinite series used successfully to deduce thermodynamics of self interaction of oxygen as a interstitial atom in two metallic systems. The predicted thermodynamic parameters values using Maclaurin infinite series and Margules. equations, are in excellent agreement with the experimental data and also our predictions are far more accurate than the predictions made by other models.

Jan 1, 1996

By R. Asmatulu

According to Darcy?s law, the rate of filtration should increase with increasing pressure drop across a filter cake. In centrifugal filtration, the driving pressure is created by the centrifugal forces applied in the free water on the surface of a filter cake. However, the pressure drop can become negative when the free water surface disappears, which makes it difficult to achieve low cake moistures. In hyperbaric centrifugal filtration, this problem is overcome using air pressure to restore the pressure differential. In the present work, various mineral and coal fines have been subjected to hyperbaric centrifugal filtration tests. The laboratory tests show that the moistures of various mineral fines, such as copper and zinc concentrates, phosphate, talc, kaolin clay, and precipitated calcium carbonate, can be reduced substantially below that achieved by conventional centrifuges. Similar promising results have also been obtained with various coal fines in laboratory and pilot-scale test programs and in full-scale plant demonstrations.

Jan 1, 2012

By Zhigao Xu, Ming Wu, Jun Qu, Rong Zhang, Wenrui Nie, Ruan Chi, Zhenyue Zhang, Zhengyan He

The leaching processes and mechanisms of weathered crust elution-deposited rare earth (RE) ores with ammonium sulfate were investigated for their high efficiency and low consumption exploitation. The leaching process is a typical reversible heterogeneous ion exchange reaction in liquid–solid systems. The raw ore and leached tailings were analyzed by SEM and FTIR. Results indicated that no dissolution or structural changes of the ores occurred during the leaching process. The migrations of RE3+, Al3+, and NHþ 4 in the leaching process were studied under various liquid–solid ratios. With increasing liquid–solid ratio, the content of NHþ 4 adsorbed on clay mineral by physical effect decreased, NHþ 4 adsorbed by ion-exchange increased, and the content of exchanged RE and Al increased until reaching equilibrium. The adsorption capacity of the RE ores for NHþ 4 remained about 0.61–0.63 mg/g. It was difficult to desorb NHþ 4 from RE ores with washing water alone. The leaching mechanism of Al was the same as RE, but the leaching of Al slightly lagged behind RE. At the optimal liquid–solid ratio of 0.4:1, the leaching efficiencies of RE and Al were 95.51% and 90.99%, respectively, and 56.65% of NHþ 4 remained in the leachate. After impurity removal and RE precipitation, the leachate can be reused by replenishing fresh leaching agent. The aim of this study is to enhance the leaching process of RE, restrain the leaching of impurities, and decrease the consumption of leaching agents.

By Kenneth Cottingham

The area described herein is situated on what is known as the Arches Fork anticline in Roane and Calhoun Counties, W. Va. When the area was first mapped, it was felt that well records would give a more intimate idea of conditions, both structural and lithologic, than could be expected from surface horizons. The surface formations are chiefly members of the Monongahela series, though northward the hilltop outcrops are those of the Dunkard. Neither series offen a key horizon sufficiently definite to be satisfactory, although the structure as determined from well records was later checked against two of the more persistent surface sandstones. In mapping the subsurface structure, the top of the Big Lime (Green-brier) was employed as the key horizon. The average depth to the top of the Big Lime varies from 1600 to 2000 ft. (487 to 609 m.), while the average thickness as indicated by well records is 113 ft. (34 m.). The oil-producing formation is the Big Injun, lying just below the Big Lime. In two instances, well records show the Lime and Injun separated by a few feet of "break." The Big Injun is recorded as having a variable thickness. Seven logs report it as missing and one gives it the maximum thickness of 105 ft. (32 m.), while the entire average for thickness is 19 ft. (6 m.). Relation of Structure to Thickness of Big Injun The seven wells reporting the Big Injun as absent were located near the anticlinal axis. Moreover, the general tendency is a thickening of the Injun on the flanks of the anticline, increasing with distance from the axis. Manifestly, this apparent anomaly has no stratigraphic basis, as the actual thickness of the Big Injun and the overlying Big Lime was determined by original deposition which no amount of subsequent folding could appreciably alter. Fig. 1 is a skeleton map of structure based on the top of the Big Lime; Fig. 2 is a cross-section showing the thickness of the Big Injun.

Jan 1, 1923

By Kenneth Cottingham

The area described herein is situated on what is known as the Arches Fork anticline in Roane and Calhoun Counties, W. Va. When the area was first mapped, it was felt that well records would give a more intimate idea of conditions, both structural and lithologic, than could be expected from surface horizons. The surface formations are chiefly members of the Monongahela series, though northward the hilltop outcrops are those of the Dunkard. Neither series offen a key horizon sufficiently definite to be satisfactory, although the structure as determined from well records was later checked against two of the more persistent surface sandstones. In mapping the subsurface structure, the top of the Big Lime (Green-brier) was employed as the key horizon. The average depth to the top of the Big Lime varies from 1600 to 2000 ft. (487 to 609 m.), while the average thickness as indicated by well records is 113 ft. (34 m.). The oil-producing formation is the Big Injun, lying just below the Big Lime. In two instances, well records show the Lime and Injun separated by a few feet of "break." The Big Injun is recorded as having a variable thickness. Seven logs report it as missing and one gives it the maximum thickness of 105 ft. (32 m.), while the entire average for thickness is 19 ft. (6 m.). Relation of Structure to Thickness of Big Injun The seven wells reporting the Big Injun as absent were located near the anticlinal axis. Moreover, the general tendency is a thickening of the Injun on the flanks of the anticline, increasing with distance from the axis. Manifestly, this apparent anomaly has no stratigraphic basis, as the actual thickness of the Big Injun and the overlying Big Lime was determined by original deposition which no amount of subsequent folding could appreciably alter. Fig. 1 is a skeleton map of structure based on the top of the Big Lime; Fig. 2 is a cross-section showing the thickness of the Big Injun.

Jan 1, 1923

By S. I. Sobol

The results of the study of the mechanism of a cathode process of cobalt electrolysis to explain disagreements in a form of kinetic equations of autoclave reduction of nickel and cobalt have been used.

Jan 1, 1993

By Wolfgang Van Hooff

Encouraged by a strongly growing and evolving market for granulated products, Paul Wurth continuously improves its granulation and dewatering technologies to provide customers with state of the art installations. Continuously developed know-how about the granulation process of iron blast furnace slag enabled application to non-ferrous materials such as Ni-Slag, Pb-Slag, Blister Copper, Cu-Matte and even TiO2-Slag, which rank among the most difficult materials to granulate. This paper identifies how critical objectives in granulation and dewatering technologies applied to different molten materials with respect to various product quality objectives can be addressed. The differences between hot and cold water granulation systems are explained, including the step from cold runner to granulation water tank. Development of a flow and pressure controlled blowing box is the latest step to optimize the granulation process in order to meet the latest standards in terms of quality, power consumption and environmental protection.

Jan 1, 2006

By J. Blodget Britton

Six different samples of anthracite, each a firm compact lump, were finely pulverized and immediately put in bottles. Portions of these were weighed and placed upon an ordinary water-bath and dried for one hour; the average loss was 1.24. The same portions were then placed in a hot-air oven, and for two hours kept at a temperature of 285° F., and, after cooling in a dry chamber, were again weighed, when there was found a further average loss of 1.22, making a total so far of 2.46. They were then immediately returned to the oven and for two hours more kept at a temperature of 530° F. and cooled and weighed again, when no further loss was found, but an average gain of .55 upon the previous weighing. The same portions were a third time placed in the oven and for about ten minutes kept at the last-mentioned temperature, and then, while still hot, were poured into one-quarter inch glass tubes, each with a bulb at one end, and heated over a Bunsen burner at a temperature below a red heat, when more water vaporized and condensed in small clear globules on the cold parts of the tubes. Fresh portions of the coals were then taken, and the total amount of water determined, and the average was found to be 3.04, or 1.80 more than was found at the temperature of the water-bath, which was perhaps a little below 212° F., and .58 more than at 285° F. Tests were afterwards made by placing other fresh portions of the

Jan 1, 1877