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By Mait Mets

In Estonia, the deformations monitoring of 1500 buildings are currently under investigation, buildings on pile foundations make up 10 per cent of these. In the following text we will be considering the behaviour of pile foundation buildings in various parts of Estonia, in differing geotechnical conditions.

Jan 1, 2002

By K. L. Bainbridge

This report describes the results of a study to determine which types of, and to what extent, mining wastes can contaminate groundwater through leaching of acid-forming or potentially toxic constituents. The primary focus of this study was on coal mining wastes, especially overburden spoils and preparation plant refuse. In addition, the potential for contamination by leachates from clean coal stockpiles was also examined. The study approach included investigation of (a) the amounts and geographic locations of mining wastes in the United States; (b) the chemical character of mining wastes, especially with regard to potentially acid-firming or toxic constituents; and (c) the extent to which acid and/or toxic components are leached from mining wastes by rainwater. To evaluate the leachability of coal wastes, a laboratory waste leaching method was developed during this study to specifically simulate the leaching process over a long-term. Waste samples collected during this study were also leached by the EPA extraction procedure and ASTM waste leaching method. Results of the three leach test methods were compared to evaluate their relative capabilities to predict the leachability of mining wastes.

Jan 1, 1980

By R. Filippone, Donald Leroux, Colin Hardie, G. Leichtle, Cesar Gomez, Jim A. Finch

"Bubble surface area flux (Sb) is the surface area of bubbles per unit time per unit cross-sectional area of flotation machine. The units are: (m2 bubble surface/s)/(m2 cell) or s -1. For bubbles of mean size db (m), s b = 6-Qg/A db where Qg is the gas rate (m3/s), and A the cell cross-section (m'). This parameter is now receiving wide attention as the possible key machine variable in flotation diagnosis and modelling. The concept is described and the potential use of sb is illustrated by work on flotation columns and mechanical cells. In column flotation of recycled paper, the dependence of ink recovery on s b was the same regardless of size of column or type of sparger. In mechanical cells, it has been established that the rate constant is related to Sb independent of impeller type.The use of s b is limited by the problem of measurement, primarily that of estimating db. A prototype probe designed to estimate db (and hence sb) based on conductivity measurements is described. Exploratory work with the probe in a mechanical cell suggests the promise of making estimation of s b routine.INTRODUCTIONFlotation is the result of interaction among variables associated with the feed particles, chemistry and the machine (flotation cell). Trying to isolate the effects of each aids in process diagnosis and is at the centre of attempts to model flotation. The machine variables that have been investigated include the air flow number, the power number and specific power (Harris, 1976). None have survived as the basis for predicting flotation response perhaps because they did not include directly the properties of the bubble swarm (or dispersion). Recently, Gorain (1 997) explored the relationship between the flotation rate constant and various ""gas dispersion"" parameters notably: superficial air rate (Jg = Qg/A, where Qg is the volumetric gas rate and A is cross-sectional area of cell), bubble size (db), gas holdup (Eg, i.e., the volumetric fraction of a cell occupied by gas) and bubble surface area flux (sb = 6.Jg/db). Of them all, Gorain et al. (1997) conclude that the latter, the surface area flux, correlated best with the flotation rate constant. This concept was adopted from column flotation where it was used to estimate, among other factors, the maximum amount of gas that could be injected (Finch and Dobby), 1990). Let's start by reviewing the concept. Following that some examples of where the concept has been applied will be described to illustrate the current interest and finally we will consider how to measure the surface area flux."

Jan 1, 1999

By A. Brown

"The mining industry is no exception to the general rule that continuing research is essential to good management; in fact, because of the imperfect state of knowledge in regard to many important factors associated with a mineral extraction, mining research assumes a position of unusual importance. On the basis of a recent visit to mining research centres in a number of European countries, the author describes their organization and their role in the mining industries of these countries. Some observations are made on Canadian mining research efforts, with a view to indicating a more systematic basis of procedure."

Jan 1, 1960

By G. N. Shannon

Keywords: inclusions, slag, modeling, interfacial energy, capillary force, particle flotation, particle separation A previously introduced model of inclusions separating across a steel-slag interface, developed by Nakajima/Okamura and Bouris/Bergeles, is expanded to include different inclusions shapes (octahedral and plate-like, besides spherical) as well as comparison between model ladle-, tundish-, and mold-slags. Investigation of the relation of these shapes with the interfacial capillary force ? which arises due to the dynamic interfacial energy during separation ? has shown that the force has a significant effect on whether the inclusion separates rapidly or settles at the interface. For the slags considered, the most significant physical property is found to be viscosity, which resulted in fast separation times for inclusions in the mold and ladle slags, relative to the more viscous tundish slag. Particle dissolution (using experimental data) is included in separation modeling.

Jan 1, 2005

By Rodrigo Prestes Limberger

A investigação do comportamento de um mandril com diferentes diâmetros ao longo de seu comprimento no forjamento incremental em matriz aberta de eixos vazados para aerogeradores é estudada. Tem-se por finalidade a fabricação de um mandril que se adeque à peça forjada e atinja o formato proposto. Através do uso de simulações numéricas computacionais com o software Simufact.forming 12, e simulações com o material modelo plasticina, possíveis geometrias de mandris foram estudadas, variando a angulação na região de troca de diâmetros ao longo do comprimento. Foram estudados ângulos de 0º, 30º e 60º, analisando o comportamento da fluência do material na região.

Aug 16, 2017

By Xiaowen Liu

The DSC/TG, IR and XRD analysis were used to characterize the heating phase transformation of illite, which came from Ouhai deposit, China. It was discovered that the dehydration and de-hydroxylation of illite carried out stage by stage during heating. The adsorptive water and layer-inter water were dehydrated from room temperature to 500°C; and dehydroxylated in the range 500°C~800°C. In these stages of process, illite?s layer structure kept almost unchanged. After 800°Cillite began to change into disorder structure. At about 1100°C, the layer structure of illite had been destroyed, and amorphous SiO2 and mullite crystallite appeared. At about 1200°C the structure of illite completely destroyed and mullite crystal phase had become perfect..

Jan 1, 2006

By Padmavathi V, M. Najamuddin, M. R. Madhav

Granular piles are one of the leading ground improvement techniques, adopted for the betterment of bearing capacity and reduction in settlements of the foundations and also to accelerate consolidation of the surrounding soil. In the recent past, there has been extensive research on the settlement analysis and behavior of granular piles under varied soil conditions. The application of these theoretical solutions to practical problems requires a knowledge of representative values of the deformation parameters of the ground and the granular piles. However, very little information is available on these parameters. The paper presents a new method for the estimation of the modular ratio of granular piles and modulus of deformation of the surrounding in-situ soil from the compression load tests. The load - settlement response obtained from the compression test results are used in the back analysis for estimating the modulus of deformation of the ground. The presence of granular bed, under the rigid plate for load testing, has been given due consideration in quantifying the proportion of load transferred on to the stone column. Based on these considerations a new method is developed to estimate the modulus of deformation of the ground and the modular ratio of the granular pile.

Sep 1, 2022

By Chung Yu Wang

DURING the time I was in charge, of this mine, from 1914 to 1915, I had occasion to read the interesting papers by T. T. Read and C. M. Weld about these deposits, to find how far their observations corroborated mine. To quote from the paper on "The Mineral Production and Resources of China" by T. T. Read:' "The iron ores at Tayeh lie along the contact between a marble and an intrusive body of a dark gray syenitic rock. * * * * At one place it is slightly magnetic, apparently having been partly reduced to the magnetic oxide by the action of reducing solutions, which have deposited small amounts of copper and iron sulphides along the foot wall." To quote from the paper on "The Tayeh Iron Ore Deposits"2 by C. M. Weld: "I find the orebodies described as occurring along an approximately E-W contact between horn-blende-granite and limestone. * * * * The granite is a granitoid rock consisting essentially of quartz, potash-feldspar and hornblende." These quotations show the differences of opinion entertained by two observers. My own study of these interesting deposits has been intermittent amid the manifold duties devolving upon a superintendent. General Description of the Deposits The deposits are situated to the west of the Yangtse River, being con¬nected with the river by a standard-gage railroad of 56 li (16.16 miles, 26 km.) in length, as shown in Fig. 1. The general topography of the region is of mature age, showing broad valleys with sluggishly meandering streams. These deposits are worked as two mines, named the Tieh Shan Mining Department and the Teh Tao Wan Mining Department; the former consisting of three orebodies more or less connected, named Tieh Man Kan, Sha Mau Tze and Lung Tung, and the latter consisting of Chang Pei Shan, Sze Tze Shan, Ta Shih Men, Yeh Chih Ping and Tsin Shan, also more or less connected, as shown in Fig. 2.

Jan 3, 1917

By Chung Yu Wang

During the time I was in charge of this mine, from 1914 to 1915, I had occasion to read the interesting papers by T. T. Read and C. M. Weld about these deposits, to find how far their observations corroborated mine. To quote from the paper on "The Mineral Production and Resources of China" by T. T. Read:' "The iron ores at Tayeh * * * * lie along the contact between a marble and an intrusive body of a dark gray syenitic rock. * * * * At one place it is slightly magnetic, apparently having been partly reduced to the magnetic oxide by the action of reducing solutions, which have deposited small amounts of copper and iron sulphides along the foot wall." To quote from the paper on "The Tayeh Iron Ore Deposits"2 by C. M. Weld: "I find the orebodies described as occurring along an approximately E-W contact between hornblende-granite and limestone. * * * * The granite is a granitoid rock consisting essentially of quartz, potash-feldspar and hornblende."' These quotations show the differences of opinion entertained by two observers. My own study of these interesting deposits has been intermittent amid the manifold duties devolving upon a superintendent. General DescriptLon of the Deposits The deposits are situated to the west of the Yangtse River, being connected with the river by a standard-gage railroad of 66 li (18.16 miles, 26 km.) in length, as shown in Fig. 1. The general topography of the region is of mature age, showing broad valleys with sluggishly meandering streams. These deposits are worked as two mines, named the Tieh Shan Mining Department and the Teh Tao Wan Mining Department; the former consisting of three orebodies more or less connected, named Tieh Man Kan, Sha Mau Tze and Lung Tung, and the latter consisting of Chang Pei Shan, Sze Tze Shan, Ta Shih Men, Yeh Chih Ping and Tsin Shan, also more or less connected, as shown in Fig. 2.

Jan 1, 1918

By Gabriel Esterhuizen

The room-and-pillar mining method is used extensively in underground limestone mines in the Eastern and Midwestern U.S. The rock mass is typically a near-horizontal, bedded deposit at relatively shallow depth. A survey of 34 mines was conducted in which data on roof spans, rock mass properties and support practices were collected as part of a National Institute for Occupational Safety and Health research project into ground control in limestone mines. The average room width is 13.5 m (44 ft), accommodating large mechanized equipment. The results show that the immediate roof beam can consist of many individual layers and can contain several near-vertical joints. In spite of the room widths, the roof is naturally stable in many mines. Observed roof instabilities can generally be related to excessive horizontal stresses or unfavorable geological structures that cause block fallout or beam failure of the bedded roof rocks. The survey showed that the rock mass quality of the limestone does not vary significantly throughout the Eastern and Midwestern U.S. Roof conditions and the need for support were found to be closely related to the thickness and competence of the first layer of limestone in the roof. The findings highlight the need to identify local geological structures and the roof beam characteristics so that support alternatives can be evaluated. Monitoring and observational technologies that are available for identifying potentially unstable roof are presented, which include: roof characterization using the Rock Fall Risk Index, automated logging of roofbolt hole drilling, microseismic monitoring and displacement monitoring.

Jan 1, 2007

By Shu Xinqian, Zhou Weining, Shan Zhiqiang, Feng Jifu

"Modified calcination conditions on the extraction of rubidium resources from muscovite (KAlz[AlSi301o](OH)2) ore are systematically studied. The impact of various factors on the rubidium leaching rate is also analyzed, including the agent types, roasting time, the mass ratio, roasting temperature, etc. The results indicate that the best agent is a combination of sodium chloride and calcium chloride, its mass ratio ofmuscovite/NaCl/CaClz is 1:0.25:0.25. Calcined at 8500 for 30 minutes, the rubidium leaching rate is up to 90%. The reaction of muscovite ore with the chlorinating agent CaC12 has been studied by TG/DSC, the calcined intermediates are identified by XRD, and the surface morphology before and after leaching is characterized by SEM. Rubidium chloride products can be obtained with a purity of 92% by using t-BAMBP extraction, hydrochloric acid reextraction and purification.IntroductionRubidium is one ofrare alkali metals, which is found in 1981 by German R.W. Bunsen and G.R. Kirchhof. Rubidium includes the following features: atomic number is 37, each atom weight 85, the body-centred cubic lattice, each unit cell has two metal atoms, and the density is 1.532g/cm3. The properties of low melting point (312.46 K) and malleability make rubidium have a strong chemical activity and photoemission. Rubidium provides a main material for manufacturing phototube with a wide range oflight waves, which possess high sensitivity and stability. Efforts are being made to carry out research on rubidium ion gngine, magnetic flux generators and thermoelectric transudcer, etc. Rubidium exists in muscovite ore(KA12[AlSh01o](OH)2 (monoclinic system and hexagonal layered structure) as isomorphism and replace the large radius of the potassium atoms, as well as part of rubidium locate between structure layers. The complex components bring great difficulty in comprehensive recycling."

Jan 1, 2013

By Gregory B. Poole

As part of a $3.5 billion program to improve the antiquated waste water system in the city of Atlanta, the Nancy Creek Tunnel is being constructed across the northwest portion of the city. This tunnel is over eight miles long and is being constructed using Tunnel Boring Machines (TBM) for the majority of the tunnel and conventional drilling and blasting for three shafts, starter and tail tunnels and four connecting tunnels, totaling 2400 feet in length. An extensive public relations program was developed for this project. A group effort by the owner, engineer and contractor produced a public relations program that both informed and educated the public of the anticipated perceptions and effects of the blasting and TBM activities.

Jan 1, 2005

By Chu E. Ho

Current methods of determining jet grout column diameters are highly empirical and site specific, and do not take into account the jet hydrodynamics and soil parameters explicitly. A theoretical model which describes the jet excavation mechanism is introduced in this paper, with the aim of providing an improved prediction tool that can be used in jetting design. The model is based on the assumption that the velocity distribution in the cutting jet is equivalent to that of a free jet with boundaries corresponding to the dimensions of the cavity excavated in the ground. The shape of the cavity formed depends on the erosional properties of the soil and jet expansion is limited by the resistance at the jet-soil interface. The model predicts that the limit of jet penetration is reached when the average dynamic pressure at the jet tip becomes equal to the ultimate soil bearing resistance. The reliability of the model, evaluated using results from four case histories of jet grouting field trials, is within ±15%.

Jan 1, 2006

By M. J. Fairweather

"The development of means to maximize the selectivity between galena and sphalerite in lead zinc ores is extremely important to the lead-zinc industry. Two challenging studies recently undertaken by Cominco will be reviewed. The first required an unusually fine grind to achieve liberation between galena and sphalerite. The second contained partially altered galena which resulted in unusual early activation of sphalerite under normal flotation conditions. Means by which lead and zinc separation were optimized in these two ores will be discussed.There are two important factors in the separation of minerals by froth flotation: particle size distribution (grind) and pulp chemistry. Pulp chemistry includes a number of factors including pH, Eh, collector type and concentration, inorganic depressants, organic depressants and activators.Grind is important for two reasons. A sufficiently fine grind is required to optimize liberation. However, if the mineral dissemination is too fine, mineral selectivity in the flotation process is impaired. Due to the hydrodynamic constraints of conventional mechanical flotation cells, flotation works best over the single decade size range between 10 and 100 microns. The majority of new ores treated by Cominco until relatively recently were comparatively simple. The major factor in their treatment was defining optimum grind size. Accordingly, the focus within mineral processing at Cominco was on grind and supporting liberation studies. The relationships between grind, liberation and flotation response are intuitively easy to understand. An idealized relationship is shown in the first figure."

Jan 1, 1991

By J. B. Forrester

In the operation of the coal mines in Utah few adverse conditions confront us. Physical conditions for the economical extraction of the coal are as near perfect as it is possible for them to be. Still several obstacles are encountered to keep up our interest and prevent us from getting in a rut. Of these I shall speak only of Burning, Wants, and Sluffing of Ribs. Should one travel the outcrop from Ivy Creek in Emery county to the Utah-Colorado line, there would be one outstanding feature indelible impressed upon one's mind. That feature is the omnipresent indications of burning in place. Viewing the eastern escarpment of the Wasatch Plateau from a distance, many splotches of dark red are plainly seen always lying above the coal floor. This stratum is a felspathic sandstone, appearing as a white line running the full length of the above escarpment and about midway between the floor of the valley and the top of the plateau. The coal bearing complex consists of shales, sandstones and coal. This complex varies from two hundred to eleven hundred feet in thickness. The number of coal seams are exceedingly variable. As a rule the argilutites form the bulk of this complex. This material is baked by the burning of the coal and the iron present is oxidized to the ferric state, coloring the shale to a dark red. This baked material forms a shingle tales that in places cover the entire complex. It is natural to expect that the most extensive burning is in the canyons facing to the south and east and on the south slopes of the ridges running to the east or west. Such, indeed, is the case. Still in this arid region many crop fires have existed upon the north slopes, especially in those canyons that face to the east. In fact today, instances are not rare where grassy north slopes, heavily timbered with balsam and fir that have attained a diameter of 14 to 24 inches, are found growing upon the disintegrated baked shingle and later development proves that the coal has been burned at least 500 feet back from the outcrop. Still these conditions are not normal. In this arid climate the south and east exposures are steep and barren, except for the scrub pine, cedar, mahogany and kindred semixerophytes. Bunch grass is also a lover of such exposures. There is very little soil found in such places; it is either blown away as fast as formed or washed away by the rare torrential rains, or the rapidly melting snow. Thus we see that the physical conditions are favorable for the starting and maintainence of outcrop fires. This brings us to the probable origin of this phenomenon. There are four probable ways' that such fires, could be started, namely:

Jan 1, 1921

By M. P. Board, J. K. Whyatt, T. J. Williams

The U.S. Bureau of Mines has been conducting a series of rock mechanics investigations at the Lucky Friday Mime in the Coeur d'Alene Mining District of northern Idaho. In the present study, the energy release rate (ERR) index was used to evaluate three underhand stope backfill parameters--cement content, density, and placement gap-to determine their influence on rock bursts. This index provides a relative measure of the likelihood of rock bursting for a given rock mass. It is known that the elastic idealization of the rock mass inherent in this method causes underestimation of stope closure and hence underestimation of the influence of backfill on rock bursting. However, this evaluation still showed that (1) changing from present practice to one in which backfill was omitted altogether would increase the ERR by 42 pct and (2) perfect placement of backfill would reduce the ERR below present practice levels by 28 pct. The easiest step toward perfect placement would be elimination of the placement gap, which accounted for half of the difference in ERR between present practice and ideal placement conditions. There was no indication that increasing initial fill strength through increased cement content would affect the ERR.

Jan 1, 1992

By Dale Preece, Steven Sobolik, Richard Jensen

Recent events demonstrate that civil and government facilities and structures face an ever-increasing need to be designed for protection against malevolent explosions. Modification of existing public structures and especially design of new ones increasingly includes provisions for explosive protection. ISEE members endorse and promote responsible application of explosives to benefit mankind and deplore any other use. However, our knowledge of explosive behavior and our ability to predict the results of explosive events puts us in a unique position to give guidance to designers of civil and public structures. Recent advances in computational methods have resulted in new computer codes with ALE (arbitrary lagrangian eulerian) simulation capabilities. Historically, lagrangian computational methods have been used for modeling solids because the mesh or discretization moves with the material. Rock breakage resulting from explosively induced shock-waves has been successfully modeled with lagrangian codes. Explosive detonation has traditionally been modeled with eulerian techniques. Eulerian methods have been used to model gases and fluids, tracking the material as it moves through the computational grid. ALE computational technology couples the two methods together in a manner never before possible. An ALE simulation can accurately treat the explosive detonation, interaction of explosive gases with air, and the impact of explosive event on nearby solid structures. ALEGRA (Budge et al. 1997 a & b) is an ALE code developed at Sandia National Laboratories. ALEGRA simulations accurately predict the explosively induced impulse on the structure to be protected. It has been applied to the analysis and design of blastwalls to protect structures and people from explosive events. The impulse calculated can be used by structural engineers to design a blastwall. ALEGRA has also been applied to predict the effect of a blastwall on explosion overpressure some distance behind the blastwall to assess the effect on people present during the event.

Jan 1, 2000

By Robert W. Van Dolah

The prevention of fires and explosions involving the combustibles and oxidants likely to be found in flight vehicles requires a knowledge of the flammability and related characteristics of these materials. This circular is a compilation of the available charactersilics data for a series of combustibles and oxidants of current interest. Vapor pressure data are presented for fluorine, oxygen, chlorine trifluoride, nitrogen tetroxide, nitric acid, hydrogen peroxide, ethylene oxide, hydrogen, ammonia, pentaborane, unsymmetrical dimethylhydrazine, monomethylhydrazine, hydrazine, and a series of hydro-carbons including decalin, tetralin, bicyclohexyl and other high-density fuels. In addition, flammability characteristics diagrams are included for each of the fuels in contact with air and, where available, other oxidants (for example, oxygen and nitrogen tetroxide). To assist in understanding these data, sections on definitions and theory and applications have been included. Each section is complete in itself and can be used separately. For example, a reader who is familiar with the general theory of combustion and detonation may find the data sections more useful than the definitions and theory and the application sections. However, since pertinent data are included in these sections, they should also prove useful to the experienced engineer interested in preventing fires and explosions.

Jan 1, 1963

By R. J. Matetic, J. S. Peterson, P. G. Kovalchik

The National Institute for Occupational Safety and Health (NIOSH) has initiated a study of a roof bolter to reduce noise exposure to mine roof-bolter operators. An important segment of this research entails determining the affect of various drilling configurations on the performance (penetration rate) and sound power emissions when drilling into granite. Test conditions included using various combinations of rotational speeds and thrusts, using 2.54- and 3.49-mm- (1- and 1 3/8-in.-) diameter hexagonal and round drill steels, using vacuum and wet conditions and using drill media of differing compressive strengths. This paper details the affects of each of these variables on the performance and sound power level emission. When drilling into granite, it was found that wet drilling generated lower sound power levels and performed better than vacuum drilling.