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By S. G. Kumar, R. G. Reddy

"Niobium aluminides offer the advantage of higher high temperature capability compared to other intermetallic aluminides due to the refractory nature of niobium. However, the reaction sequence in Nb-Al system is sluggish and currently there is a great interest in the processing aspects of these materials. In the present study, a systematic investigation was undertaken to compare the effect of different powder metallurgy processing routes on the phase relations and microstructure of 66Nb-22AH2Ti (in atom percent) alloy. The three different process routes adopted were: (i) cold pressing followed by reaction sintering; (ii) cold pressing and hot pressing followed by sintering; and (iii) arc melting, hydride-dehydride process to make the alloy powder followed by cold pressing and then sintering. The samples are analyzed by XRD, Optical Microscopy, SEM-EDS and EPMA. The analysis showed that alloy pellets made from pre-alloyed powders i.e., arc melting followed by hydride-dehydride process, gave good densification and more Nb3Al formation.1. IntroductionTo improve the performance standards of turbine engines, materials scientists are challenged to develop materials that have· high thrust-to-weight ratio with high specific strength, high specific modulus and good environmental properties at elevated temperatures. The conventional high temperature materials like nickel based superalloys are high in density and hence many of the high temperature materials scientists have focussed their attention on intermetallic aluminides like Fe-AI, Nb-AI, Ni-AI and Ti-AI in recent years. The phase relations and properties of alloys based on Fe-AI, Ni-AI and Ti-AI are fairly well known whereas little is known about the alloys based on niobium aluminides."

Jan 1, 1996

By N. H. Grace

"IntroductionDURING the past half century, the economy of Western Canada was largely centred on agriculture. However, the impact of World War II has led to an acceleration in the development of a variety of natural resources so that, today, Western Canada is experiencing great industrial development. Consequently, the availability •of low-cost energy assumes prime importance. In the final analysis, industrial growth and expansion are intimately linked to the energy resources.Coal ReservesHas Western Canada adequate coal reserves to meet the present accelerating demand for power in the days that lie ahead? This question must be answered before detailed consideration can be given to the probable patterns •by which various energy sources in Western Canada may be expected to meet the expanding demand. Figure 1 indicates the extent and distribution of the Canadian coal reserves, the data having been prepared by Dr. B. R. MacKay for the Royal Commission on Coal in 1946 (1). The amount of readily recoverable coal is listed as one-half the quantities shown on the chart. It is interesting-to note that upwards of 90 per cent •of the Canadian coal reserves .are located in the three most westerly Canadian provinces. It has been estimated that the coal reserves, at the present rate of mining, would be adequate for about 3,000 years. Consequently, it may be concluded that the coal •reserves in Western Canada •are indeed adequate to meet tremendous energy demands for many centuries. When the oil and natural gas have been exhausted, the great coal reserves will still be available."

Jan 1, 1953

By Chase E. Sutton

The porosity of a sand is usually the measure of its capacity for holding fluid, although porosity is sometimes selective; that is, a small percentage of the actual pore space (voids), particularly in fine-grained sandstones, may be isolated by the cementing material which prevents the entrance of fluids under normal conditions. Obviously, however, porosity determinations are essential to an engineering study of underground conditions of an oil field, and a simple and reliable method of obtaining a reasonably accurate figure for average porosity is desirable. This report describes a method suggested by Ruasell,3 which was used by the writer in the preparation of a report on the Texhoma-Gose pool, Archer County, Tex.4 The conditions in this pool were particularly favorable for obtaining an average porosity figure, in that some 30 to 35 core samples of the pay sand were available for analysis.

Jan 1, 1928

General Gold was discovered in quartz veins at Wiluna in 1896, and the first lode was discovered in 1904. Since 1896, some 2.5 million ounces of gold have been produced from the Wiluna area. The mining operations at Wiluna are 100 per cent owned by Wiluna Gold Pty Ltd, a wholly owned subsidiary of Wiluna Mines Ltd. Oxide and sulphide gold ore is extracted by conventional open pit mining techniques, and ran-of-mine ore is processed through two separate circuits. The oxide circuit has a capacity to treat 600 0(X) tonnes per annum and the sulphide circuit has a capacity to treat 400 (XX) tonnes per annum. Additional gold is won by dump leaching sub-grade oxidised ore and by retreating of primary ore flotation tailings from previous operations. Testwork carried out in 1990 indicated the viability of leaching dumps of run-of-mine oxide ore, and in June 1991 Signet Engineering of Perth, WA, was awarded an EPCM contract to construct a nominal 2.5 million tonne dump leach facility, for a total construction estimate of 51.75 million.

Jan 1, 1994

By Dave Shook

A Mineral Processing facility in Montreal has recently implemented a leading-edge intranet solution for monitoring the performance of plant operations, and providing condition-based maintenance. This innovative multi-faceted software implementation incorporates: web-delivered plant information systems; area-wide control loop performance assessment (using sophisticated algorithms to evaluate poorly performing controllers); and integrated alarm management functions. The system has enabled a project to improve plant operations through better process control. Maintenance technicians, engineers, supervisors and managers all can see the performance of the controllers, and the performance of the plant itself, through webdelivered graphics and reports. Information is combined from many sources, real-time, historical, relational and analytical, to provide a complete picture of plant operation. The web-based solution centralizes the administration of user access, and simplifies the deployment of several different kinds of information to many desktops. It is an extensible system that allows users to create and share their own web pages and data views. The paper will discuss the solution architecture and the improvements the I.T., operations, maintenance, and engineering groups have experienced, and overall benefits to the facility.

May 1, 2002

By R. E. MacDougall

Very few mineral properties spend their entire lifespans from discovery to depletion in the hands of one owner. More likely, properties will have several owners, and partial interests may change quite often. Similarly, mineral companies are bought and sold with frequency, in recent years at what appears to be an accelerating rate. The reasons for selling a property can be manifold -need for additional capital in other parts of the business, need for development capital, realization of a large gain at a perceived high point in the market, pessimistic commodity outlook, retirement of principals, or resolution of estate problems. Regardless of the reasons for a sale, there are specific steps that logically follow. Spruce up the business, package the information, market the property, negotiate the terms, close the sale, and make sure it stays sold. Adherence to certain very basic ground rules in property sales can maximize the profits and minimize the effort.

Jan 1, 1990

By Jurgen te Kook

State-of-the-art for subsidence calculation are stochastical models. Although these models were successfully used all over the world they have their limitations due to the fact that they are not based on mechanical laws. For example the models did not take the rock mass structure and the rock mass characteristics into account. Therefore in a research program the skills of geomechanical numerical models for subsidence calculation were investigated. A case study shows that numerical models which are in principle based on the elastic theory are suitable for subsidence prediction. Due to the principles of these models the results are not sufficient in the case of multiple seam extraction. More extended geomechanical numerical models like FLAC and UDEC were investigated in further steps of the research work. Up to now large area geomechanical models require unrealistic long calculation times if the level of detail is similar to that of small scale calculations. Due to this it was necessary to implement a simplified description of the rock mass structure and characteristics. Different case studies show that this approach is successfull for subsidence calculation by numerical geomechanical models even for multiple seam extraction.

Jan 1, 2008

By C. Y. Sun

China is a country with abundant resources of tungsten, taking one of the world?s top-positions regarding both the total reserve and the amount of industrial production. China?s tungsten resources occur mostly in multi-metallic deposits rather than in single-metallic deposits. China?s multi-metallic tungsten ores have the characteristics of coexistence with other valuable components such as molybdenum, bismuth, copper, sulfur and fluorite. These ores are usually low in grade and difficult to process. The technological challenge in mineral processing lies in separation of multi-metallic components in these complex ores and a comprehensive utilization of natural resource. Several cases of industrial practice of processing China?s typical multi-metallic tungsten ores are presented.

Jan 1, 2014

By José E. Rondoña

El presente trabajo desarrolla un estudio comparativo de la producción de dos tipos de hornos usados en la fundición de cátodos de zinc en la planta de La Oroya, para asi determinar cúal es el equipo más idóneo para futuras expansiones del proyecto. De los puntos comparativos se encontró que el horno SICE desarrolla más productividad de personal en operaciones, así como en el rendimiento de la energía eléctrica. Mientras que respecto de las consecuencias de las filtraciones del metal, se encontró que el horno Ajax es el más adecuado, dado que la producción de barras se afecta solo en la producción que el horno afectado representa en la instalación total. Por ende, es conveniente el uso de dos hornos SICE tamaño mediano dada la capacidad y productividad de esta.

Nov 20, 1967

By B. Das

The processing of banded iron ore by direct anionic and reverse cationic flotation to produce pellet grade concentrate is investigated. This low-grade iron ore, known as banded hematite quartzite (BHQ) contains 41.8% Fe, 41.5% SiO2, 1.2% Al2O3, and 0.5% LOI. The flotation behavior of BHQ is studied by varying the effect of concentration of collector, frother, dispersant and pH. Oleic acid and dodecylamine are used as the anionic and cationic collectors respectively. The parameters that gave the best results in cell flotation are utilized in 100 mm diameter flotation column. All the results are compared with regard to the iron grade and recovery in concentrate. It is observed that, anionic collector with dispersant dosage of 220 g/ton, at pH ~8.5 is selective and yielded a high-grade iron concentrate with low silica as impurity. Also, it is possible to achieve an iron concentrate with 64% Fe at 30-37% weight recovery. The characterization studies of the BHQ ore using X-ray diffraction (XRD) technique and liberation analysis with QEMSCAN® are carried out. The sample contains 58.8% hematite and 37.7% quartz and the liberation of hematite particles are found to be 90.3% in -25 µm size. An alternative statistical modeling approach called response surface methodology was also undertaken to optimize the operating parameters in order to maximize the iron grade and recovery. The predicted results by the model are in agreement with the experimental values.

Sep 1, 2012

By E. Poiate, P. R. Cabral, A. V. N. Santos, P. V. M. Costa, C. S. Amaral, A. M. Costa

This paper discusses the design of underground salt caverns, opened by solution mining, for the production of brine and storage of natural gas under high pressures. The caverns are located in the salt basin in Maceio City, Alagoas State, at the northeast region of Brazil. Special attention is given to the geomechanical structural design of the caverns using computer codes specially developed for the simulation of excavations in salt rock formations, considering validated constitutive creep laws under different initial stress states and temperatures. The behavior of sedimentary rocks intercalations presented in the salt layer is simulated using elastic-plastic models. The excavation of the caverns by solution mining is also simulated starting from a geostatic initial equilibrium state of stresses, with a unique formulation only implemented in these computer codes, without the need of the application of boundary stresses to the model in order to develop the initial state of stresses. These computer codes have being used in the design of several clusters of caverns for brine production used as raw material of Poly Vinyl Chloride (PVC) of the Chemical Industryin Brazil. These computer codes and methodology were also applied to the design of the underground conventional potash mine in the state of Sergipe, overlying tachyhydrite and carnallite with very high creep strain rate. They have also been used in the design of the pre-salt oil wells through thick layers of stratified salt rock in Santos Basin, for the exploration and production of the pre-salt reservoirs in Brazil. The constitutive creep equations implemented in the codes are based on a double mechanism creep law. The creep constants adopted in the simulation are taken from a previous investigation carried out on an experimental panel of the potash mine, considering the stratified geology with different salt rocks of the basin where the mine is located. These constants were also obtained by lab tests under different confined and differential stresses and temperatures.

Jan 1, 2015

By Bawden WF, Paynter JT

This investigation involves laboratory testing and stability analysis of paste fill at the Golden Giant Mine. Site-cast samples are tested in unconfined, confined, and consolidated-undrained triaxial compression. Pore pressures during shear and consolidation characteristics are measured to determine both drained and undrained shear strength parameters and assess the potential for undrained loading. Liquefaction potential is also considered. A limit equilibrium solution is used to obtain factors of safety against failure of the fill during mining of adjacent stopcs

Jan 1, 1998

By Ricardo Dobry, Alain Pecker, George E. Leventis, Ralph B. Peck

"This year’s DFI Outstanding Project Award is for the design and construction of the foundation scheme for the largest cable-stayed bridge in the world. In 1993, Gefyra, SA (a French/Greek consortium led by VINCI of Paris, France) was awarded a €750 million ($1billion+ USD) Concession Contract to design, build, fi nance, operate and maintain a three-span cable-stayed suspension bridge connecting the Peloponnese, Greece’s southernmost peninsula, with the mainland across the Gulf of Corinth. The contract extends over a 42-year period, 7 years for design and construction and 35 years for operation. The project was fi nanced through a combination of public funds, private equity and bank loans. Alternative foundation concepts that were considered included traditional driven piles, deeply embedded caissons and soil improvement. PROJECT CHALLENGESThe extreme technical challenges faced included:??Weak foundation soils composed of soft alluvial deposits consisting of interbedded layers of granular and cohesive materials with thin layers and lenses of gravel and liquefi able sand pockets; rock is believed to be at a depth of 1,000 m (3,500 ft) or more.??A very deep seabed exceeding 60 m (200 ft).??The requirement to withstand the collision of 180,000-ton tankers traveling at 16 knots.??Maximum wind forces of 250 km/hour (155 mi/hour).??Design seismic forces corresponding to Richter magnitudes of 7.0+ with peak ground accelerations of 0.48 g at seabed.??Design tectonic movements of 2 m (7 ft) in any direction between any two adjacent bridge pier foundations/pylons.Considering subsurface conditions and local seismicity and water depths, foundation design and construction methods were the key drivers for this project. In large part, the success of the project is owed to the unprecedented partnering and collaboration between all partners involved fostered under the leadership of Jean Paul Teyssandier and Gilles De Maublanc of VINCI Group (France) who served as lead Concessionaire and General Contractor. The joint venture’s lead Greek partners were Elliniki Technodomiki/AKTOR and J&P/AVAX. Alain Pecker of Geodynamique et Structure (France) served as lead Geotechnical Consultant/ Designer while Buckland and Taylor (Canada) served as Design Checkers with Ralph Peck and Ricardo Dobry (U.S.) as Special Advisors on foundation issues, Langan International/Langan Engineering and Environmental Services P.C. (George E. Leventis, Gregory Biesiadecki and Diane Fiorelli) served as Technical Advisor on geotechnical, geodynamic and foundation/marine construction issues."

Jan 1, 2007

By Richard J. Mainiero, Michael J. Sapko, Marcia L. Harris

Since 1988, there have been thirteen documented incidents in the United States and Canada in which carbon monoxide (CO) is suspected to have migrated through near surface strata into structures or other enclosed spaces as a result of nearby trench blasting or surface mine blasting. From these incidents, there are thirty suspected or medically verified CO poisonings and one fatality associated with these incidents. To better understand the variables contributing to this hazard, the National Institute for Occupational Safety and Health (NIOSH) carried out a small- scale field study to identify key factors that may contribute to the migration of CO through the ground. NIOSH conducted single- hole heavily confined experimental test shots to measure the radial pressure pulse as it propagated through surrounding monitoring holes to determine if a relationship existed between the pressure pulse and resulting CO measurements afterwards. NIOSH also monitored blasts at an airport construction site. Following the detonations, the concentrations of CO, nitric oxide (NO), and nitrogen dioxide (NO2) were monitored for several days in the surrounding satellite holes. The peak CO measurements relative to distances from the shots were compared. Pressure histories and peak particle velocities (PPV) were measured at monitoring boreholes. It was found that the differential pressures recorded within the boreholes give some indication as to the likelihood of CO appearing, whereas the PPV measurements do not seem to be as good an indicator for potential CO migration. In this limited study, changes in barometric pressure had very little influence on removing the trapped detonation products, whereas applying a vacuum to the monitoring holes was effective in reducing the entrapped CO concentration.

Jan 1, 2005

By C. G. McLachlan

INTRODUCTION The work described in the following paper was under-taken with a view to determining, if possible, the relative importance of some of the phenomena on which flotation seems to depend, in the hope that, if this information could be obtained, it would be of value in dealing with the problem as a whole. At the outset, brief reference will be made to three papers which had a considerable bearing on the course followed in the present investigation. In 1919, Langmuir, in a paper on 'The Mechanism of the Surface Phenomena of Flotation', showed that mono-molecular films of very great stability could be produced on solid surfaces with oleic acid, but that pure paraffin oil, though spreading readily on a dean dry surface, was easily displaced by water.

Jan 1, 1926

By Jessica Egan, Daniel Hodouin, Mohammed Reza Khalezi, Steve Bellec, Claude Bazin, Carl Duchesne

"A model for gold leaching was developed and implemented into a simulator. The simulator uses a description of the ore that is based on the mineral composition and precious metal content. The model accounts for the distribution of minerals and precious metals through the size intervals. An ore texture model based on precious metals and minerals grain sizes within the ore is used to predict the exposed surface of the species in the various size intervals. A model is proposed to predict the rate of dissolution of any species dissolution using the exposed surface, particle size, cyanide and oxygen concentrations, temperature, pH and agitation. The flow of slurry through a leaching tank is modelled using a parallel arrangement of perfect mixers to simulate a bypass and a Cholette-Cloutier mixer model. The simulator can be used for circuit optimization but was developed to provide an environment for learning the basic concepts of process analysis methods. Examples are given to illustrate the application of the simulator for planning tracer tests and sampling campaigns.INTRODUCTIONThe constant pressure to improve the operation of processes that are already close to optimum imposes to plant engineers to be aware of the available process analysis tools and to be able to use them to assess process operation and make a diagnosis to possible problems. Some of these tools are:•,Sampling the streams of a process;•,Data reconciliation;•,Analysis of mixing in reactors;•,Estimation of rate parameters;•,Optimal tuning and flow sheet modification;•,Automatic control and real time optimization.Although some of these tools are part of the curriculum of many university engineering programs, the students are not exposed to actual process analysis problems. In addition the complexity of the ore dressing processes compounded with unavoidable measurement errors and plant disturbances can discourage many motivated engineers. These factors often lead to an incomplete valorization of the collected data and a poor return on the investment associated with the sampling, testing and analysis of the samples.Simulators are readily available for process optimization (Yalcin and Shang, 2006) by allowing:•,The simulation of various flow sheet configurations;•,The simulation of a change of operating conditions;•,The simulation of various control strategies;•,The training of plant operators.However few simulators have been developed with the objective of providing an environment for training plant engineers and technicians to the use of tools for process analysis and optimisation."

Jan 1, 2008

By P. D. Rao

Although phosphorus is a very important biogenic element, its concentration in coal is generally low. Phosphorus concentrations typically range from 0.001 % to 0.229% in raw coals of the contiguous 48 states. Some Alaskan coals in the Cook Inlet region contain horizons unusually high in phosphorus. A foot by foot analysis of deep drill core, containing 70 ft. of sub bituminous 'C' coal from the Beluga coal field, Alaska, showed certain increments contained as high as 17.03% P2O5 in the coal ash; 1.01 % P on a moisture-free coal basis. Crandallite has been identified by electron microprobe analyses as a phosphorus numeral in these coals. The authors could quantify calcium, barium, strontium and phosphorus concentrations from the coal attributable to crandallite. These high phosphorus coals provided a unique opportunity to study the association of phosphorus in coals using chemical fractionation for exchangeable cations and acid extractable elements. Since the source of high phosphorous horizons in Cook Inlet coals is attributed to volcanic ash, it is suggested that the profiles of acid extractable phosphorous concentration may be useful for coal seam correlations.

Jan 1, 1992

By D. A. Paice

A power supply to operate fluorescent or mercury vapor lamps from 300 volt dc coal mine trolley wires has been developed for the Bureau of Mines. A high frequency regulated inverter unit incorporates ballasts for a mix of lamp loads up to 650 watts. For 600 volt trolley systems an additional power converter unit was developed to step down the dc voltage to 300 volts for the inverter unit. Both units have operated in a working coal mine for over 12 months without need for servicing. The lamp load in these tests included two 100 watt mercury vapor head lamps and six 75 watt fluorescent lamps.

Jan 1, 1979

By J. E. Shelton

This presentation covers the results of laboratory studies conducted by the Bureau of Mines Mineral Dressing Section, Northwest Electrodevelopment Laboratory, Albany, Oreg., on alluvial sands from Dismal Swamp, Bear Valley, and Cascade, Idaho. The search for radioactive minerals has led to the reexamination of alluvial deposits; in the process of this reappraisal the frequent presence of minerals bearing columbium and/or tantalum was toted. Because of increased demand for these metals by the defense industries and because these industries depend upon foreign sources for their supply the domestic alluvial black sands are being considered, as a possible domestic source. However, utilization of these alluvial deposits depends upon development of methods of concentrating these valuable minerals. The primary objective of the test work was the study of the effect of attrition scrubbing, sizing, magnetic, electrostatic, and gravity separa¬tion as methods for concentrating and recovering the columbium and tantalum-bearing minerals, samarskite, euxenite, ilmenorutile, and columbite.

Jan 1, 1955

By Robert B Sosman

The relative temperature distribution within a coke oven and among the ovens in a battery can be obtained automatically for the operator's guidance by sighting a total-radiation pyrometer on the face of the coke as it is pushed out, and recording the surface temperature. Keeping the instrument clean and keeping its view of the coke unobstructed by smoke and dust are the principal problems. Typical records from three plants are presented in this paper, showing that the temperature patterns are reproducible. Development OF Method The method of coke pyrometry described in this paper was introduced in 1936 by E. A. Lee, then Assistant Superintendent, now Superintendent, of the Coke Plant at Lorain Works, National Tube Co., Lorain, Ohio. At the request of the Coke Committee of the United States Steel Corporation, the Research Laboratory of the Corporation undertook to adapt the method to the somewhat different conditions met with at the Gary Works of the Carnegie-Illinois Steel Corporation, Gary, Ind., and at the Clairton Works of the same Corporation at Clairton, Pa. This work was done in cooperation with the Leeds and Northrup Co. of Philadelphia and later with the Brown Instrument Co. Division of Minneapolis-Honeywell Regulator Co., Philadelphia. We of the Research Laboratory wish to express our appreci- ation of the courtesies extended by Mr. Lee, by A. N. Cole, Superintendent of the Gary coke plant, and by D. P. Finney, Assistant General Superintendent in charge of coke-plant operations at Clairton. We are also indebted to the instrument companies for the loan of a part of the equipment. At Gary and Clairton the instruments were installed and various experiments were made by J. W. Bain, of the Research Laboratory of the United States Steel Corporation. Pyrometry of Coke The coke inside a by-product oven is almost completely inaccessible to pyro-metric instruments. The temperature in the walls can conceivably be measured with thermocouples, but the atmosphere is usually strongly reducing, a condition well known to be destructive to the accuracy of the customary high-temperature couples. In some plants, periodic readings are taken with an optical pyrometer sighted into the top of the combustion flues. This is a useful measure for safety and general control, as it tends to prevent the damage that would result from overheating of the ovens. It does not, however, tell much about the temperature of the coke itself, because of the continually changing gradient in the wall between the coke and the combustion chamber. The best indication of the temperature of the coke itself must therefore be obtained by observation of the product as it is pushed out of the oven. The human eye is very sensitive to variations in brightness of a surface, and particularly to differences in brightness over a continuous hot surface.

Jan 1, 1943