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By G. L. Fitzpatrick

Preliminary results of an experiment in seismic holography indicate that the techniques of acoustical holography may be successfully used with seismic waves to determine the size and general shape of underground objects. This experiment was carried out under field conditions on a moderately large scale compared with the typical laboratory experiments in acoustical holography. The object to be mapped was a 100-foot-diameter, spherical, low-velocity zone of explosively fractured rock in oil shale at an average depth of 80 feet. The seismic wavelength of the Fourier component wave used in making the seismic holograms was 50 feet at a frequency of 140 cps. The hologram sampling aperture was 226 feet square and was sampled by 441 geophones in a 21 by 21 rectangular array. One novel aspect of the experiment was the use of a wide-band polychromatic explosive source of seismic waves rather than a narrow-band quasi-monochromatic vibrator source. A successful laser reconstruction of the object image from a lensless Fourier-transform hologram in the form of a 5/l6-inch-square photographic transparency is illustrated. The size of the underground object measured from the laser reconstruction of the object and the size inferred from a knowledge of the amount of explosives used to fracture the site and the tensile strength of the oil shale are found to agree.

Jan 1, 1972

"The objective in controlled blasting is to reduce overbreak to control the final pit wall slope, shaft, drift ditch, bench, etc. to the final planned excavation limit. The six main types of controlled blasting utilized today are:1. Line Drilling2. Cushion Blasting3. Smooth Wall Blasting4. Buffer Blasting5. Presplitting or Preshearing6. Air Deck Presplitting"

Jan 1, 1994

For a large scale open pit mining and concentrating operation, on a low-grade disseminated ore body, it is possible to set an approximate lower bound on economically feasible operating scales and an approximate upper bound on economically desirable scales in a relatively straight forward manner. The optimum scale ofplanned operations, with respect to the objective ofmaximisation ofthe net value ofthe orebody, will have to be arrived at by iterative planning runs, but it may be expected to lie close to this upper bound. The effects of infrastructural costs and of the addition of a risk premium to the cost of capital, to form the discount rate for planning purposes, are considered theoretically and by worked example. It is concluded that a perceived special, unsystematic, risk should not be accounted for by the use of such a risk premium as this is inducive to placing a greater amount of investment capital at risk, for no greater return-rate to investment.

Jan 1, 1986

By E. Kamon

This report summarizes completed research pertaining to the reaction of human subjects exposed to Self-Contained Breathing Apparatus (SCBA) stressors during escape conditions (viz., resistance breathing, C02 breathing, hot air breathing, and static positive facepiece positive pressure breathing) and the development of an automated breathing and metabolic simulator (ABMS). Volume I contains summarizes of the studies performed under this contract. Volume II is an appendix which contains more detailed descriptions of these studies.

Jan 1, 1984

By Mark S. Stagg

Blast-induced ground vibrations from surface coal mine, quarry, and construction blasting were measured and analyzed for frequency content and duration characteristics. Eighteen commercially available ground vibration measurement systems were evaluated in the field and laboratory for linearity, accuracy, and crosstalk. Buried, surface, and sandbagged transducer placement methods were compared, along with peak and vector-sum measurements. The recommended minimum frequency ranges for ground vibration instrumentation are 2 to 150 Hz for coal mine and quarry blasting, and 5 to 200 Hz for construction and excavation blasting. When higher or lower frequency vibrations are possible, as in construction blasting or for a quarry shot close to a residence, care should be taken to insure proper choices of instrumentation and vibration criteria. Several instruments operating in these ranges are available, and all but one of the seismographs tested fell within ±3-dB accuracy limits (+41 pct, -29 pct). Waveform recordings of all three ground vibration components are recommended as the peak amplitude and frequency may vary among the three. Peak or vector-sum readings are adequate if only amplitude levels are desired. The soil density matched box should be anchored or buried, particularly for high-frequency, high-amplitude construction blasting.

Jan 1, 1980

By F. C. Gennari, D. M. Pasquevich

With the gradual exhaustion of natural rutile, there has been extensive research into its synthesising from lower-grade titanium minerals. The removal of Fe from pseudobrookite (Fe2TiO5) by chlorination was studied, using both isothermal and non-isothermal thermogravimetric measurements. Correlation of the results obtained from element distribution maps, scanning electron microscopy, energy-dispersive X-ray analysis and phases detected by X-ray diffraction in the chlorinated samples showed clearly two associated processes. First, the pseudobrookite particles reacted with chlorine and iron was removed selectively as FeCl3(g), leaving a solid residue rich in the TiO2 phases anatile and rutile, separated from an inner layer of unreacted pseudobrookite by a distinct interphase boundary. Second, chlorine allowed TiCl4(g) to form in the reaction bed, where it removed iron from the Fe2O3 crystals as FeCl3(g) and substituted Ti through a pseudomorphic reaction

Jun 21, 1905

By Federico Schwalb

Actualmente la minera Yanacocha opera cuatro mineras a tajo abierto que abastecen a tres operaciones de lixiviación de oro. Paralelamente a estas, la minera planea otro yacimiento a fin de asegurar su nivel de producción. En este sentido, el presente trabajo señala el nuevo yacimiento denominado Quinua, que está ubicado al suroeste de las operaciones actuales. Esta nueva área incluye la construcción de instalaciones de lixiviación, planta de aglomeración, sistemas de recolección, transferencia y manipulación de solución y el tratamiento de soluciones en una planta de procesamiento Merrill Crowe ubicada en el área de Yanacocha Norte.

Sep 13, 2001

By William A. Enrico

Umicore acquired the Pirdop Smelter in a privatization offering by the Bulgarian government in September 1997. Since that time, an investment program has been conducted to increase capacity to 225 000 tons per year of anode copper, while improving the environmental performance to meet Bulgarian and European standards. A significant part of this investment program involved reconstruction of the three Peirce-Smith converters and the associated gas handling system. During the period June, 2000 through April, 2002, converter capacity was increased, the existing water-cooled hoods were replaced, the waste heat boiler was replaced by two evaporative coolers, the dry ESP's were rebuilt and extended, and a Converter Control System (CCS) installed. From 2002 until the present, a continuous improvement of operating and environmental performance has been achieved. This paper will describe the converter reconstruction project, the operational, maintenance, and environmental improvements achieved since then and additional projects presently under consideration.

Jan 1, 2005

By R. P. Mohring

The South African Coal Industry had its beginnings in the Eastern Cape in 1859 when coal was mined to satisfy the fledgling settlements in the Eastern Cape. The growth in the industry was relatively slow up to the early 1970s when, firstly, the export business was expanded coupled with a major increase in the quantity of coal converted to liquid fuels and utilized for power generation. To meet this increased demand the industry developed many new operations employing the latest mining technology and systems. Coal production in South Africa reached 204 million tons in 1996 and revenue from exports reached R8 billion making it the second-largest foreign exchange earner after gold. In his address Rick P. Mohring describes the role coal plays in the international energy scene and outlines South Africa?s position as a producer and consumer of coal, and the challenges facing the industry. A wide range of steam-coals are produced to satisfy both the local market (power generation, coal conversion and the metallurgical industry) and the export steam-coal market. South Africa is in a unique position regarding the export market as it is still a relatively low-cost producer and is geographically well-placed to play in both the European and Far East markets. There are, however, a number of challenges facing the industry. To retain our competitiveness in the international market, ways of minimizing the cost pressures caused by high-cost inflation, increased environmental protection obligations and a decreasing quality resource base need to be sought. Locally the coal mining industry has a major role to play in Eskom?s goal of reducing the real cost of electricity by 15% in the next three years. Safety and health, productivity and the adaptation of the latest technology are issues being addressed by the industry to maintain its dominant position within the South African economy.

Jan 1, 1997

By G. W. Grove, E. E. Quenon

"INTRODUCTION During September, October, and November 1946 the Safety Division of the Bureau of Mines, off' the United States Department of the Interior, Pittsburgh, Pa., tested four new types of self-contained breathing apparatus and approved them in accordance with Schedule 13C. Approval was granted with the proviso that certain specifications outlined on the approval plate be made fully effective, and with the understanding that established safe practices in training in the care and use of self-contained breathing apparatus are of major importance.The excellent records made during the past 30 years in the safe use of self-contained breathing apparatus, some of which required the almost continuous wearing of apparatus during several hours daily for days, weeks, or months, may be attributed largely to the Bureau's system of rescue organizations, selection of physically fit rescue workers, effective training, and educational work done in rescue and recovery operations during fires or following disasters and in the care and use of self-contained breathing apparatus. Loss of life during wearing of breathing apparatus was due almost invariably to poorly assembled or otherwise defective apparatus, poor physical condition of the wearer, or insufficient training or some incorrect procedure.The newly developed breathing apparatus are of much simpler design than the conventional type used for the past several years; however, it is just as important to select rescue crews carefully and to train them properly in the care, use, and limitations of the new types of apparatus as for the older long-established types, if anything like safety is to be achieved in using them. The Bureau of Mines considers that 1/2-hour and 3/4-hour self-contained breathing apparatus should be used only as auxiliary equipment in mine rescue and recovery work, and their capabilities and limitations should be well understood by those who wear them."

Jul 1, 1947

By L. Nahai

Iran's petroleum industry is nearly 50 years old and the oldest in the Near East. According to published figures, Iran ranks third in production and reserves in the Near East. These reserves (including probable reserves) are estimated at 35 billion barrels and constitute about 11 percent of the world's total. Iran is the sixth largest producer of crude petroleum in the world. The 1961 output of more than 430 million barrels was 5 percent of total world output for the year. In the same year, Iran ranked fourth among world petroleum exporters, providing 8.4 percent of total world exports.

Jan 1, 1963

By Leandro Moosher

A crescente geração e disposição de resíduos sólidos tornou-se preocupante, para tanto busca-se um fim adequado aos mesmos. Este trabalho objetivou avaliar a viabilidade técnica, ambiental e financeira do uso das areias fenólica e verde usadas de fundição como co-produto em substituição parcial ao agregado miúdo areia natural de rio na fabricação de blocos de concreto para pavimentação. Produziu-se 3 traços com 25% e 50% de substituição da areia natural por uma composição de areia de fundição com os mesmos equipamentos e parâmetros comerciais e obteve-se resultados satisfatórios, como a resistência à compressão através do traço rico em consumo de cimento e com 25% de substituição da areia natural pelo co-produto atingindo 37,2 MPa, cerca de 6% acima do mínimo requerido pela NBR 9780. Já na avaliação ambiental esses blocos foram classificados como Resíduo Classe II-A Não Inerte e a análise de viabilidade financeira mostrou custo 1% menor que o bloco convencional.

Aug 8, 2018

Effect of Hydrophobicity and Frother Concentration on Bubble-Particle Interactions in Turbulent Flow

Sep 13, 2010

Ultrasonic Extinction for High Resolution Particle Size and Concentration Analysis

Sep 13, 2010

By Gandhi

Piled raft foundation under uniformly distributed vertical loads has been analyzed using Finite Element Method. The soil is considered to be linear elastic, isotropic, homogeneous. The raft,pile and the soil have been idealized with eight noded brick elements. Parametric study have been carried out varying pile length, soil modulus, raft thickness, and pile spacing. Design charts have been produced to achieve 50% load sharing between pile and raft for optimum design. Data available in literature is compared with the design chart results and found satisfactory.

Jan 1, 1996

Deep level block caving as a mining method is becoming more popular due to the fact that it is the lowest cost per ton underground extraction system. However, many block caves do not achieve their full potential due to draw horizon instability. In this paper five design rules are given to overcome this problem. The design rules described are applicable for slusher and trackless block caves where the operational depths exceed 500 metres.

Jan 1, 1999

By Tian Sugui

By direct aging treated, creep properties measurement and microstructure observation, the influences of the direct aging treatment on the creep behaviors of Hot Continuous Rolled GH4169 superalloy are investigated. Results show that the creep resistance of Hot Continuous Rolled GH4169 superalloy may be obviously improved by directly aged treatment. Under the applied stress of 700MPa at 660, the creep lifetime of the alloy is enhanced to 126h from 60h. During hot continuous rolling, the deformation features of the alloy are the twinning and the double orientations slipping of the dislocation activated within the twinning regions. After direct aging treated, the alloy displays a smaller grain size, and the finer g² phase is dispersedly precipitated in the matrix of the alloy, which is thought to be a main reason of enhancing creep lifetime of the alloy.

Jan 1, 2010

By Mark E. Emerson

1967 will be remembered as the year the world realized it was running out of silver. In May of this year a new era in tin the history of the white metal was begun as the power of the U.S. Treasury to regulate world .silver markets was staggered by one of the most intense speculative flurries in recent times. In the past few months the price of silver has risen from $1, 29 to over $1.80 per troy ounce and with it have spiraled the prices of a host of silver-bearing consumer items. Legislation has, been enacted to conserve our coinage and meager silver stocks and today large quantities of non-existent silver are trading hands at a fast pace on the commodity exchanges throughout the world. Now that the price of silver has been set loose, forces are in motion to dull the world's appetite for silver. At the same time there is strong incentive to provide greater quantities of silver to satisfy the world's hunger' for the metal.

Jan 1, 1967

By K. E. Stanfield

[Asphalt ~~d road oil ar8 the principal products manufactured from Wyor.1in~ Ilblack oilo" \r,hich, beca.use of th?lir hig.~ E\.sphal t and hig} sulfur COi.1Jce~1t, .!?re difficult e':ld costly to refine into hi?;h-gra.de motor f 101s, burning oils. and lucri ants by presont mothods. Accordin~ly. the demand for truHle asphaltic renidl urn for the construction of roade aJ1.d other uses is 3. controlling factor in the quantity of crud~ oil prod ICed. The increasiilg -u.tilization of special aST>ha.lts as ine}""Pensive bonding, in-]

Jan 1, 1941

By B. M. Larsen, J. W. Campbell

Several articles have recently been published discussing the conditions necessary for accurate measurements of temperatures in the open-hearth steel furnace. In the course of a study of refractories service conditions in steel furnaces, the present writers have taken temperatures in several open-hearth shops in the Pittsburgh district. The conclusions, as to conditions necessary for accurate measurements of temperature, are somewhat at variance with those of other investigators. The subject is closely connected both with the close control of steel-making and the prevention of overheating of the silica refractories used in roofs and walls. It is becoming more and more important to obtain furnace temperatures of fairly definitely known accuracy. At present, the most useful instrument for such measurements is the disappearing-filament type of optical pyrometer. This method of measurement has formed the basis of most other discussions on the subject and was also used by the writers. Previous Investigations In 1916, Burgess' made perhaps the first systematic series of measurements in steel furnaces. The emissivity figures of 0.40 for liquid steel and of 0.53 to 0.65 for liquid slags had been determined by the Bureau of Standards and were used by Burgess in this work. These correction factors are still being used and are regarded as fairly accurate, so that the tapping and teeming temperatures on metal streams given by Burgess should be very nearly correct. Most of his temperatures of furnace roofs and slag surfaces were taken while flames were present in the furnaces and include a few roof temperatures above 1700' C. (3100' F.).

Jan 1, 1927