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By C. M. McKinney

This report contains Bureau of Mines routine analyses of 492 samples of crude petroleum from 470 United States oilfields, each of which produced 2,500 barrels a day or more during at least 1 of the years 1946-56. The fields are listed alphabetically by State and field names in table 1, with information on the geographical and geological sources of the samples. Table 2 summarizes the general characteristics of the crude oils and analytical and computed data determined from the analyses. A previous report 4 contains similar analyses of 283 important United States oilfields; some of them are repeated in this report. Many fields for which analyses previously were published are represented by new analyses, which include data not previously reported. Refractive index nu and specific dispersion, ng minus nD divided by the density, for some of the distillate fractions are included in the analyses of 316 of the crude-oil samples. This is the first Bureau of Mines report on analysis of crude oils to contain such data, and their use in calculating hydrocarbon-type composition of the fractions is explained.

Jan 1, 1957

By D Bradshaw, R Dunne, S Farrokhpay

It is well known that clays affect the flotation performance, and many of the refractory gold ores around the world contain clay minerals. Therefore, an ore sample from the Carlin Trend was selected for this study as these ores contain large quantities of clays. The presence of clay minerals in an ore makes it susceptible to a range of variables, such as the solution chemistry determined by pH and the chemistry of the rheology modifiers. The viscosity of the ore slurry was measured as a function of solid concentration and particle size distribution, in addition to using different rheology modifiers and pH regulators. The results were correlated with the ore flotation performance. It was found that various reagents known commonly as dispersants or rheology modifiers have different effects on the ore slurry viscosity. This study revealed that the gold flotation recovery can be improved by changing the pulp rheology.CITATION:Farrokhpay, S, Bradshaw, D and Dunne, R, 2013. Rheological investigation of the flotation performance of a high clay containing gold ore from Carlin Trend, in Proceedings World Gold 2013, pp 333-340 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Markus Thewes, Mario Galli

"INTRODUCTIONProject-related studies showed that lab tests are a helpful tool for the planning of EPB tunneling and soil conditioning in cohesionless soils. This type of ground commonly represents the extended application range for EPB shields, which demands for a treatment with additives. Considering soil conditioning with foam, so far, approaches exist for the investigation of the foam quality and of the conditioning behavior of soils (e.g. (EFNARC GUIDELINES 2001 2003)), but not any standards for testing procedures related to soil conditioning. State-of-the-art research on the topic is and was conducted for example in Bochum (Germany) cf. (Budach 2012; Maidl 1995), in Lyon (France) cf. (Quebaud et al. 1998), in Oxford and Cambridge (Great Britain) cf. (Borghi 2006; Peña Duarte 2007), in Delft (Netherlands) cf. (Bezuijen and Schaminée 2001), in Turin (Italy) cf. (Borio 2010; Peila et al. 2013; Vinai 2006), and in Aachen (Germany) cf. (Vennekötter 2012). Additionally, applied science is reported by the tunneling practice and suppliers of conditioning agents. Although the research focus in all these and further studies varied, similar test methods and test series were applied. A standardization of essential properties and testing methods (setup and procedures) however did not take place. The results from laboratory testing can only function as index values for practice because in the studies, production and application of the conditioning agents mainly takes place under atmospheric conditions. Nevertheless, the tests enable basic understanding of feasibility as well as processes and interactions going on during soil conditioning. For recommendations for standardized and reproducible testing see (Budach 2012; Budach and Thewes 2015).The most extensive investigations on the flow behavior of soil-foam mixtures have been performed by using the slump test from concrete engineering, cf. (DIN EN 12350-2 2009-08), which originally is applied on evaluating the workability of fresh concrete. Although this test does not describe the actual flow behavior, it rather represents an index on the workability, very much experience exists with this test method. Besides others, the workability – or flow behavior – of the EPB support medium certainly is a major factor of influence on the properties of the material in the excavation chamber and thus, for effective tunneling with EPB shields, cf. (Galli and Thewes 2014). For a summary of various investigations on the workability of conditioned soils using the slump test and resulting recommended slump ranges see (Budach 2012; Vinai 2006). Thereof, slumps between 10 and 20 cm have been reported as suitable workability for EPB applications. However, there is actually not much known about the real flow behavior of soil-foam mixtures related to rheological properties such as the viscosity (?) or potential yield stresses (t0). These physical values are necessary for a realistic determination of face pressure, for the design of required torques, and for an evaluation of the material flow at different locations in the excavation chamber, in the screw conveyor or on the conveyor belt. To generate a linear pressure distribution at the tunnel face, as it is assumed a priori, a low-viscosity fluid is favorable, whereas in the screw conveyor, a high-viscous fluid is needed for a controlled pressure decrease. On the conveyor belt, yield stress plays an important role preventing deliquescence and spilling from the belt. Attempts in characterizing the actual flowing of soil-foam mixtures have so far only been made by few researchers, the application of rheometry is rare."

Jan 1, 2016

By S. H. Ash

The Pennsylvania anthracite region is composed of four fields, namely, the Northern, Eastern Middle, Western Middle, and Southern. It is in the eastern part of Pennsylvania and is shown on figure 1. The anthracite industry is confronted with a crucial problem of inundation by water impounded in underground pools in many mines and by infiltration of water from streams and pools on the surface (3). The deposits of anthracite in the United States are limited virtually to Pennsylvania, and the difficulties of this industry have been commonly considered as a State problem rather than a national one (1, 4, 6, 7). Anthracite was discovered in Pennsylvania in 1762, and the first mining company was formed in 1793. It was not until 1812 that anthracite began to receive recognition in the Philadelphia market as a domestic fuel, and by 1838 the annual production was nearly 1 million net tons. Since anthracite mining began, mine water has become progressively more difficult and costly to handle because of the extraction of anthracite both underground and along the outcrops of the beds, until at the present time mine drainage is a major anthracite-mining problem. Mine water is handled at the anthracite mines as follows: (a) by pumping, (b) by drainage tunnels, (c) by combination of pumping and drainage tunnels, and (d) by water hoists (hoisting water by means of large buckets) (4, 5,6, 7). This paper covers removal of the water from mines by means of pumping plants. Pumping is indispensable in the production of anthracite (5). The cost of pumping mine water has increased progressively since anthracite mining began. Some collieries have been forced to discontinue mining because of the high cost of pumping.

Jan 1, 1950

By John A. Organiscak

Enclosed cabs are a primary means of reducing equipment operators? silica dust exposure at surface mines. The National Institute for Occupational Safety and Health experimentally investigated various factor effects on cab air filtration system performance. The factors investi­gated were intake filter efficiency, intake air leakage, intake filter loading (filter flow resistance), recirculation filter use, and wind effects on cab particulate penetration. Adding an intake pressurizer fan to the filtration system was also investigated. Results indicate that intake filter efficiency and recirculation filter use were the two most influential factors on cab penetration performance. Use of the recirculation filter reduced cab penetration by usually an order of magnitude over the intake air filter alone because of the multi­plicative filtration of the cab interior air. Intake air leakage and filter loading affected the cab penetration to a lesser extent, while wind had the least impact on cab penetration between the calm and 10-mph wind velocities tested. Adding an intake pressurizer fan notably increased intake airflow and cab pressure with only minor changes to cab penetration. A mathematical model was developed that describes cab penetration in terms of intake filter efficiency, intake air quantity, intake air leakage, recirculation filter efficiency, recirculation filter quantity, and wind penetration.

Nov 1, 2008

By Kenneth L. Cashdollar

The Mine Safety and Health Administration (MSHA) and the West Virginia Office of Miners? Health, Safety, and Training (WVOMHS&T) investigated the explosion at the Sago Mine in West Virginia, which occurred on January 2, 2006, and resulted in 12 fatalities. As part of the investigation, the agencies requested that the National Institute for Occupational Safety and Health?s (NIOSH) Pittsburgh Research Laboratory evaluate the effects of explosions on specific mine ventilation seals and other structures and objects at its Lake Lynn Experimental Mine (LLEM). The results of the LLEM study would assist MSHA and WVOMHS&T in a more thorough understanding of the various questions that arose during their investigations of the explosion. Six large-scale explosion tests were conducted in the LLEM from April to October 2006. The protocols for these tests, and in particular the procedures for constructing various Omega block seals, were developed mainly by MSHA and WVOMHS&T. NIOSH developed the experimental procedures at the LLEM that would provide the required range of explosion pressures against the seals. Three 40-in-thick seal designs using Omega 384 low-density block were constructed in the LLEM and exposed to various explosion pressures. These seal designs are referred to in this report as the ?2001 design,? the ?hybrid design,? and the ?Sago design.? The 2001-design Omega block seal (80 in high) located in crosscut 2 of the LLEM survived all six explosions, with pressure loadings up to 51 psi. The 2001-design Omega block seal (88 in high) in C-drift was destroyed during Test 2, which subjected the seal to a head-on explosion that resulted in a pressure loading of 51 psi. The height difference between the two seals and the orientation of each seal to the explosion were contributing factors. The higher seal would be weaker for the same seal thickness. The hybrid Omega block seal in crosscut 3 survived an explosion at a pressure loading of 25 psi and failed during another explosion at a pressure loading of 39 psi at the seal. Based on these tests, it seems that the hybrid seal design is weaker than the 2001 seal design. The Sago Omega block seals were constructed in crosscut 3 and C-drift before Test 3. The crosscut 3 seal survived a pressure loading of 18 psi and was destroyed during an explosion at a pressure loading of 35 psi at the seal. The C-drift seal survived a head-on explosion that resulted in a pressure loading of 21 psi and was destroyed during an explosion with a pressure loading of 57 psi at the seal. Based on these LLEM tests, it seems that the Sago seal design is weaker than the 2001 seal design, yet it still complied with the requirements of 30 CFR 75.335(a)(2) that were in effect at the time of the mine disaster. During these LLEM explosion tests, the distance of seal debris travel was also measured. In Test 5, the C-drift seal was destroyed during a head-on explosion that resulted in a pressure loading of 57 psi, and the seal debris was thrown over 500 ft. In Test 6, the C-drift seal was destroyed during a head-on explosion that resulted in a pressure loading of 93 psi, and the Omega block debris was thrown over 900 ft. During these tests, the explosion pressure effects on other structures and objects were also documented. Unless otherwise specified, all of the pressure data listed in this report represent the highest recorded smoothed (averaged over 10 ms) explosion pressure loadings. The information in this report was used by MSHA and WVOMHS&T as supporting data in their analyses and investigative reports of the Sago Mine explosion.

Sep 1, 2009

By Mohsen Elsayed, Amr Sallam, Ahmad Mohamed, Xuebing Zheng, Mohamed Alrowaimi

The foundation is an essential component of the wind turbine that ensures continued operation under stable and safe conditions. Both shallow and deep foundations are utilized to support wind turbines including gravity spread foundation, anchor foundation, pier or drilled shaft foundation and pile and pile cap foundations. Conventional methods were typically utilized to design the wind turbine foundations. With the advances in numerical modeling in the geotechnical field, foundation designers may utilize numerical analysis to design wind turbine foundations. Geotechnical numerical packages allow modeling structural components and soil-structure interaction that is usually neglected in conventional methods. Furthermore, the subsoil conditions, geometries, stress-strain behavior, boundary conditions and load staging can be modeled, minimizing the assumptions and generalization. This results in better understanding of the stress strain behavior of the foundation leading to optimized foundation designs. This paper includes a brief review of current foundations used to support wind turbines with an emphasis on post tensioned single pier foundations. The current conventional foundation design methodologies and state-of-the-art foundation design utilizing numerical modeling of the single pier foundation will be discussed. Two case histories where the single pier foundation, designed using numerical modeling, were utilized to support the wind turbines will be presented. INTRODUCTION The foundation is an essential component of every wind turbine that ensures continued operation under stable and safe conditions. Turbine manufacturers provides load specifications for designers to be utilized for wind turbine foundations design. Loads include bending moments, torsional moments, lateral forces and vertical forces in both operational and extreme wind conditions. Essential specifications under seismic conditions might also be provided in seismic prone areas. Turbine manufacturers also include foundation design criteria including minimum rotational stiffness, minimum horizontal stiffness, maximum allowed inclination and maximum allowed lateral movement under both operational and extreme loads. Geotechnical explorations and evaluations are typically performed at early stages of the wind development projects. The field explorations usually include Standard Penetration Test (SPT) borings, Cone Penetration Test (CPT) Soundings, geophysical surveys, and laboratory tests to define soils stratification system and soil strength and compressibility characteristics. The most critical soil parameters for turbine foundation design are shear strength parameters (cohesion and friction), shear modulus, Poisson’s ratio, and unit weight. The depth to the groundwater table is also a crucial parameter in design. Advanced field explorations techniques such as Dilatometer Tests and Pressuremeter Tests may also be utilized. Laboratory tests for foundation design typically include index parameters, consolidation and triaxial tests.

Jan 1, 2019

By Manoj Kumar, Vinay Kumar, Nikhil Dhawan, Manish Wadhwa

"Electronic waste (e-waste) is a collective name given to discarded electronic devices such as Television, Cellular Phones and Personal Computers. Among the heterogeneous metals present in the e-waste are the base metals: copper, aluminium, nickel, tin, zinc, iron and precious metals: gold, silver, palladium, platinum apart from several hazardous and halogens metals. Hence there is a need to recover these metals from electronic scrap by recycling and then re-use, which can meet large amount of metals demand. Hydrometallurgical processing was employed for the recovery of metals from television printed circuit board (TV PCB). Different lixiviants such as hydrochloric acid, Sulphuric acid, and nitric acid were used to understand the dissolution behavior of copper, iron and lead present in the TV PCB. Effect of increasing concentration of nitric acid was also studied. Selective recovery of tin over 95% in the form of tin oxide was precipitated. The precipitated tin oxide was identified by X-ray diffraction technique. Tin oxide of purity more than 99.9% was obtained.IntroductionThe electrical and electronic industries comprising computers, television, mobiles, etc, which are manufactured utilizing printed circuit, boards, capacitors, resistance, soldering material etc. During production, at the end-of service life and degradation due to the advanced version with latest features generate valuable metallic and non-metallic constituents. European Union Council on waste electrical and electronic equipment (WEEE) has classified these into different categories as listed in Table 1 [Streicher-Porte et al., 2005]. Among these the information technology, telecommunications and consumer equipment constitute electronic waste (e-waste) [EC, 2002]. Almost all e-waste consists of an integrated part of printed circuit boards which is a valuable source of several metals such as copper, tin, lead, aluminium, iron, silver, gold, platinum etc. [Relay et al., 1990]."

Jan 1, 2008

By Kim Verbeken, Evelien Van de Steene, Marc Verhaege, Jeriffa De Clercq

"AbstractThe industry is confronted with stricter discharge levels and an increasing awareness to avoid toxic waste (such as heavy metal containing sludge obtained in physicochemical water treatment) and recover valuable metals. This can be realized by ion exchange or by electrodeposition. Both techniques however show an optimum concentration range to efficiently remove and/or recover metals: electrolysis can recover the metal in its metallic form but suffers from low efficiency when applied to diluted solutions, whereas ion exchange can only be applied economically in the low ppm range.A combination of ion exchange followed by electrodeposition was applied to an industrial wastewater. The strong acidic ion exchange resin was stripped with H2SO4 giving a solution of 9g/L nickel. From this solution, nickel was electrodeposited in an ammonia buffer on a Ti-mesh cathode with high current efficiency. It is shown that organic compounds (surfactants, brighteners, …) present in the industrial wastewater do not influence the recovery process.IntroductionAlmost all rinse waters emerging from metal plating plants are generated during the washing operation of plated materials. These solutions with low metal content must either be recycled within the process or be discarded to the surface water after decreasing their metal content to acceptable levels determined by the local environmental regulations, which become more and more stringent. Today, the most commonly used practice is a physico-chemical treatment (precipitation) and a resin post treatment to meet the standards. A more sustainable approach should use a technology to recover efficiently the metal or metal salt without the production of sludge and the effluent should be consistent with environmental regulations."

Jan 1, 2008

By Carlos Maurício Fontes Vieira, Sergio Neves Monteiro, Diogo Neves Henriques

"This work evaluates the effect of incorporation of an ornamental rock waste into an industrial clayey body used for roofing tiles fabrication. Formulations with 0, 10, 20 and 30 wt.% of waste were prepared by replacing the sand in the industrial clayey body. The plasticity of the formulations was determined by the Atterberg limits. Specimens were fabricated by 18 MPa press-molding and then fired from 850 to 1100oC. The specimens were tested to determine the water absorption, linear shrinkage and three points bending flexural strength. The results indicated that the waste improves the extrusion performance of the clayey body by decreasing its plasticity. The use of the waste was beneficial to the water absorption and mechanical strength of the fired clayey ceramic at temperatures above 1000 ° C.IntroductionOrnamental rock is a natural resource available in the municipal area of Santo Antônio de Pádua and located 150 km from the city of Campos dos Goytacazes, northe of state of Rio de Janeiro, Brazil. Intense industrial activity related to ornamental stones, especially gneisses, is traditionally occurring in the region. After mining, the flagstone is submitted to sawing to obtain blocks and then, after a manual operation, the final products are small flagstones [1,2]. During the sawing operation, a sludge composed of water and fine particles of rock is generated. A monthly production of 1000 tons of ornamental rock waste is estimated to be produced at Santo Antônio de Pádua. The final disposal of this waste has brought serious environmental problems. Since most industries do not have an adequate sludge treatment, the waste is contaminating the soil and underground waters as well as obstructing rivers and lakes.Ceramic bodies industrially fabricated in the municipal area of Campos dos Goytacazes, 280 km from the city of Rio de Janeiro, are still empirically elaborated using a mixture of local clays. These clays are predominantly kaolinitic mineral, associated with high plasticity. Due to the excessive plasticity of the ceramic bodies, it is common to have dimensional defects in the final products after the drying and firing processes. Moreover, the kaolinitic structure and the presence of aluminum hydroxide confer a refractory behavior to the local clays. This impairs sintering during the firing operation. In the case of clay ceramics for civil construction, this results in greater porosity associated with elevated values of water absorption and low mechanical strength [3,4]. To avoid these problems, it is necessary to reformulate the ceramic body composition. The addition of both non-plastic materials to reduce plasticity and fluxes to condition the refractoriness is a possible alternative."

Jan 1, 2008

By Nicola Baldo, Marco Pasetto

"Recycling of tyre rubber in the road pavement, may be one of the best way to reduce waste tires in large quantities and, at the same time, improve some engineering properties of asphalt mixtures. The paper discusses the results of an experimental study, developed in order to analyse the potentialities of crumb rubber from road tyres in bituminous mixtures, using the dry process. Two types of porous asphalt mixtures and reference mixes without rubber were formulated by the traditional Marshall methodology, and mechanically evaluated by means of the Indirect Tensile Stiffness Modulus test, the Creep test (with confinement), and the Indirect Tensile Fatigue Test. Results of this study indicate that the tyre rubber has a positive influence on the performance characteristics, depending also on the grading and volumetric properties of the mix being studied: an interesting increase of the fatigue life, a better stiffness behaviour at lower temperatures and a bigger permanent deformation resistance at high temperatures are guaranteed. Introduction Recycling the rubber from used tyres, in the construction of road pavement layers, is potentially one of the more interesting and advantageous solutions from both the technical and environmental points of view, in order to reduce the total amount of car and lorry tyres to dispose. In road-building techniques, a technology, termed “wet”, for modifying bituminous binders with crumb rubber has by now become well consolidated. There have been numerous scientific studies conducted on this technology and its applications, particularly in the United States, where it has been adopted and codified in specific technical regulations (ASTM D-6114). If the wet process can be considered amply tested, the same cannot be said for a second technology, termed “dry”, which deserves careful study to evaluate its suitability and advantages. In “dry” processes, the rubber is usually used as a partial substitute of aggregate of equivalent grading and mixed with bitumen after integrating the crumb rubber in the lithic skeleton."

Jan 1, 2008

By Ryosuke Matsuoka

Keywords: Tantalum capacitor, Scrap, Recovery, Titanium, Chlorination A recycling process for tantalum from capacitor scraps using an oxidation process followed by mechanical separation and chemical treatment was investigated. This study demonstrates that sintered tantalum electrodes inside the capacitor scraps can be mechanically collected after the oxidation of the scraps in air, and high-purity tantalum oxide powder (Ta2O5) was efficiently recovered after chemical treatment. By reducing the Ta2O5 obtained through magnesiothermic reduction, tantalum powder with 99 mass-% purity was obtained. Using the chlorination for tantalum recovery was also investigated, and the tantalum or tantalum compounds were reacted with chloride wastes such as FeClx. It was found that tantalum was effectively separated and purified when tantalum powder is reacted with FeClx at 1100 K under an argon atmosphere. This recycling process utilizing chloride scrap has now been extended to other reactive metals such as titanium.

Jan 1, 2004

By Frank Haehnig, Kurt Kogler

"With a height of 200 m, a crown width of 626 m and a concrete volume of 1.6 million m³, the Kölnbrein Dam in the upper Malta valley in Carinthia / Austria is the largest concrete dam in Austria. Boasting a storage capacity of 200 million m³ with a received water load of 54 MN, this is one of the strongest arch dams in the world.During its construction from 1974 to 1977, the dam was equipped with a comprehensive monitoring system capable of comparing developing deformations and stresses with the design values.With a planned reservoir level of 1,900 m a.s.l. the dam saw the reservoir level of 1,860 m a.s.l. breached in the year 1978. This led to extremely high seepage losses of up to 200 ltr/sec and a rise in the foundation water pressure up to 100% of the dam’s height. These observations were caused by the development of horizontal cracks in the area of the middle dam blocks, between the lowest inspection walkway and the waterside.As a consequence, power plant operations had to significantly be reduced and a number of additional measures were carried out – though these did not lead to the desired sealings.The developer subsequently decided that the dam should undergo a general rehabilitation from 1998 to 1994 in accordance with a concept developed by Professor Lombardi. This concept involved erecting a 50 m high support structure with a concrete volume of 500,000 m³ on the airside of the dam, along with the addition of neoprene bearings to transfer 1.2 million tons of the horizontal load. These measures were able to reduce the deformations in the dam enough so that mostly load-bearing injections into the cracks in the dam’s concrete could successfully be carried out by way of targeted grouting measures using injection resin (RODUR) specifically developed for this purpose.In the years 1998 - 1994, a total of 130,000 m of grouting, monitoring and control drillings were executed, and around 200,000 kg of synthetic resin was injected into the cracks in the dam’s concrete.These measures have ensured the dam‘s uninterrupted operation since 1994. A number of small re- injections were again carried out on the contact surface in the years 2011 and 2012."

Jan 1, 2016

By Rajarshi Pramanik, Nirjhar Dhang, Dilip K. Baidya

"This paper performs the reliability evaluation of pile foundation under vertical loading condition using the concept of fuzzy set theory. The uncertain parameters are expressed as fuzzy numbers. Monte Carlo simulation technique in conjunction with fuzzy set theory and fuzzy reliability index approach are implemented in evaluation of the probability of failure of pile foundations. The results are validated through some well established methods such as, First Order Reliability Method (FORM), Second Order Reliability Method (SORM), and direct Monte Carlo Simulation (MCS). Response surface method (RSM) is used to approximate the original limit state equation through second order polynomial. The effect of the position of the water table is also highlighted. Finally, the effect of the variation of applied load is examined and it is observed that the fuzzy reliability analysis gives more conservative estimate of failure probability than the other methods.INTRODUCTIONCivil engineering structures, such as high rise buildings, bridges, offshore platforms etc. are always subjected to vertical as well as horizontal loads. To support these structures, pile foundations are generally the solution in most of the situation. It transmits load from the superstructure to soil at a reasonably great depth. This transfer may be by vertical distribution of the load along the pile shaft or a direct application of load to a lower stratum through the pile tip. Different methods are available to estimate the capacity of piles embedded in different types of soil and under the application of vertical and horizontal loading. To consider the variability in soil and other unforeseen able situation, generally a reasonable value of factor of safety is used to estimate the designed capacity of the pile. Recent developments have shown a trend to place the treatment of uncertainty on a more formal basis, in particular by applying the results of reliability theory to geotechnical engineering. Keeping in mind the importance of pile foundation in the engineering structures it is essential to maintain a high structural safety which result in increase in reliability. The probability theory has been proved to be a powerful tool for representing variability in mathematical models. The variability associated with soil parameters and the modeling uncertainties are needed to be considered for the reliability assessment purpose.Recent development (Zhang et al. 2005; Misra and Roberts 2006; Haldar and Babu 2008; Basu and Salgado 2012; Teixeira et al. 2012; Pula and Rozanski 2012; and Chan and Low 2012) showed that the reliability analysis of pile foundations subjected to axial as well as lateral load has been one of the important current research topic in geotechnical field. Probabilistic based performance criteria were quantified for a single pile and pile groups in cohesionless soil by Eloseily et al. (2002). A p-multiplier approach was incorporated into the analysis to modify the p-y curve for a single pile to obtain the p-y curve for individual piles in a pile group. A statistical analysis of set up capacity of pile was carried out from the database of a large number of pile testing data in clay by Yang and Liang (2006). Load and resistance factor design (LRFD) using FORM was used for examining the different load and resistance factor for different target reliability index. Limit state analysis of drilled shaft was performed by Misra and Roberts (2006) in probabilistic framework. The fuzzy based reliability analysis (Dodagoudar and Venkatachalam 2000; and Park et al. 2012) of the earth slope was reported in the literature. Dodagoudar and Venkatachalam (2000) presented a new approach, called fuzzy point estimate method (FPEM) for reliability evaluation of earth slope. Park et al. (2012) reported a hybrid approach, fuzzy set theory in conjunction with Monte Carlo simulation technique, to determine the failure probability of earth slope. Second Order Reliability Method"

Jan 1, 2015

By Suzanne R. Hess-Brittelle, Sharon L. Schulz, Tyler J. Quick, Amy F. Ebnet

"Abiquiu Dam is a rolled earth fill dam with impermeable core located on the Rio Chama in New Mexico. Abiquiu has had a history of excessive seepage through the fractured sandstone abutments since water was first impounded in 1963. The foundation was treated with a single row grout curtain in the cutoff trench prior to placement of the embankment. During the 1960’s and 1970’s, the grout curtain was extended 1,000 ft. into both abutments and sections of the foundation beneath the embankment were regrouted. Grouting of the foundation beneath the embankment required drilling through the embankment. Drilling fluid loss or loss of circulation within the impervious core was observed during multiple phases of supplementary grouting and during verification drilling following the 1970’s grouting program. It is likely that the drilling methods employed for these grouting and drilling programs caused hydraulic fracturing of the impervious core. The fluid losses in the embankment may be related to seasonal shutdown layers in the embankment or benches in the abutment foundations. In addition, it is likely that the impervious core was fractured from grout pressures during installation of grout pipe through the embankment.INTRODUCTIONAbiquiu Dam is located on the Rio Chama in New Mexico and consists of a rolled earth fill dam with impermeable core, controlled outlet works, and an uncontrolled rock-cut spillway. The dam was authorized for flood control and sediment retention and was designed as a dry dam, holding flood pools for relatively short durations. The foundation is comprised of Permian and Triassic age, interbedded mudstones and sandstones that were deposited in an active braided stream system. Sandstones are moderately fractured and have variable aperture and infilling. Generally speaking, joints are near vertical. Abiquiu has had a history of excessive seepage through the fractured sandstone abutments since water was first impounded in 1963. The foundation was treated with a single row grout curtain in the cutoff trench prior to placement of the embankment. In 1966-1968, the grout curtain was extended 500-ft into the left abutment and the foundation beneath a 560 ft. section of the embankment was re-grouted. In 1978-1980, the grout curtain was extended 1,000 ft. into the right abutment, an additional 500 ft into the left abutment and the foundation beneath the right 520-ft section of the embankment was re-grouted. The alignments of these grout programs are shown in Figure 1. Grouting of the foundation beneath the embankment required drilling through the embankment. Drilling fluid loss or loss of circulation within the impervious core was observed during both phases of supplementary grouting and during verification drilling following the 1978-80 grouting program. It is likely that the drilling methods employed for these grouting and drilling programs caused hydraulic fracturing of the impervious core. In addition, it is likely that the impervious core was fractured from grout pressures during installation of grout pipe through the embankment. This paper provides a summary of the drilling and grouting methods used during these programs and the potential for damage to the embankment."

Jan 1, 2016

By Martín Reyes

Iron concentration by ion flotation techniques, from sulfate solutions in presence of zinc was studied in a laboratory flotation column by continuous mode using a synthesized sand shell plate sparger, an anionic collector, promoters, and surfactant propylenglicol 400. Effects of experimental parameters, such as the concentration of reagent: potassium amyl xanthate and dithiophosphate, superficial gas velocity, and superficial liquid velocity were studied in terms of the recovery and enrichment of Fe (III). The results show that the iron elimination from the solution in the presence and absence of zinc (II) are of 59 % and 72 % respectively. The flotation efficiencies decrease with an increase of the concentration of xanthate and air flow rate. The best recovery was achieved, at Jg 0.1 cm/s, Jl 0.72 cm/s and a mixture of xanthate and dithiophosphate as promoter. It was also demonstrated that it is possible to selectively separate and concentrate iron (III) from solutions containing zinc. The behavior of iron ion flotation in a flotation column is reported in this research as a gas hold up, superficial gas velocity, bubble size and superficial bubbles area flux function. The results show that the extraction of aqueous ions of metal iron by ion flotation is strongly affected by: [C], Jg (cm/s), eg (%), Db (mm), Jl (cm/s), y Sb (s-1).

Jan 1, 2009

By M. Omneya El-Hussaini, M. Galal Abdel Wahab, A. Mohamed Mahdy, M. Fathi El Shahat

"Um-Gheig Pb-Zn representative sample was collected from the main adite of Um-Gheig mine along Red Sea coast in Egypt. Its chemical analysis shows that, it contains 16% Zn, 2.3% Pb, 0.1% Cd and 0.1% B as elements of interest. After H2SO4 agitation leaching, the chemical composition of Um- Gheig Pb-Zn deposit ore residue assayed 2.26% Pb, 1.5% Zn, 0.085 % B and 0.01% Cd. This residue was leached with 20% HCl at S/L ratio 1/3 for 2 hours at 80o C. The chloride leach liquor was found to contain 18 g/l Pb, 13 g/l Zn, 0.1 g/l Cd and 0.75 g/l B with the corresponding leaching efficiencies 79%, 86%, 100% and 88% respectively. Lead was precipitated from the chloride leach liquor using concentrated H2SO4 to obtain PbSO4 with precipitation efficiency 96%. While boron was extracted by the selective resin Amberlite IRA743 with loading efficiency of 80%. On the other hand, Zn and Cd were precipitated using Na2S solution with 86.7% and 100% recovery efficiencies respectively.IntroductionLead-zinc ores occur in Egypt in a few localities distributed along the Red Sea coast between El Qusier and Ras Banas.. The reserve of the ore deposits has been estimated by Soviet and German Experts to be about 900,000 Ton, [1]. Onal et al., [2] recovered Pb from Pb–Zn sample containing 10.17 % Pb and 10.98 % Zn from Aladag in Turkey. El-Sherif, [3] used concentrated HCl to leach lead-zinc ore sample of Um-Sammuki area in Egypt. As had been published by Marchioretto et al. [4], the precipitation of heavy metals with lime, sulfide and caustic soda are the most commonly used economical methods for metal removal. Lead was completely removed from the anaerobically digested sludge by precipitation with NaOH and Na2S at waste water treatment plants. Mahdy et al., [5] had successfully extracted boron from the bittern solution of Qaron Lake by ion exchange resin (Amberlite IRA 743). The extraction of boron was mainly depending upon the pH value. They extracted 80% of boron at pH 5.5, while at pH 3.9 about 74% boron was extracted. Kabay et al. [6] used the column-mode to remove 1g/l of boron from geothermal waste water of the Kizildere-Geothermal Power Station by using Diaion CRB 02 Nglucamine- type chelating resins. In this regard, the removal of lead, cadmium and boron allow the residue to be reclassified as non hazardous material."

Jan 1, 2008

By Michael Gebman, Jack Gerwick

"With the opening of the new San Francisco-Oakland Bay Bridge East Span, the former bridge and its caisson foundations are being demolished. Caisson foundations are in the path of a future shipping channel and therefore need removal down to the mudline 50 ft below water (MLLW). For the first caisson to be removed (E3) a mechanical demolition was performed above the waterline and an implosion was done for the remaining caisson down to mudline. Mechanical demolition consisted of excavators operating from either on top of the caisson, from work platforms or from barges. The demolition was implemented on a trial basis with a successful implosion on November 14, 2015. The work was conducted in an environmentally sensitive area, with measures taken to protect fish, marine mammals and birds. This demolition technique was cost effective, faster to execute, and had a better environmental impact then an alternative option. The demolition, measures implemented to protect the environment, outcome, and lessons learned are presented.INTRODUCTIONThe California Department of Transportation needed a cost effective and environmentally friendly solution for removal of the remaining San Francisco-Oakland Bay Bridge (former East Span) caisson foundations, starting with caisson E3. This was necessary to clear a future shipping channel. One option was to construct a steel cofferdam around the caisson to allow demolition in the dry down to the mudline. This option would take years to complete, be cost prohibitive, and its noise would disrupt aquatic life and birds throughout the cofferdam construction and demolition. An alternative option was implemented on a trial basis to conduct a mechanical demolition of the caisson above waterline along with an implosion of the remaining caisson down to mudline. This had the clear advantage as a cofferdam was not needed, and the demolition project duration would be approximately 6 months, instead of several years for the cofferdam option. The potential impact on aquatic life and birds from the implosion was a concern, as the location is environmentally sensitive; however, measures were implemented to minimize these impacts. As presented in this paper, this demolition option was implemented on a trial basis for Caisson E3. The technique succeeded and will now be used on the remaining caissons.BACKGROUND INFO ON CAISSON E3The reinforced concrete Caisson E3 is the largest caisson which supported the former East Span of the Bay Bridge. It was constructed in 1934, with the Bay Bridge opening in 1936. Figure 1 shows the project location. The caisson had a cell arrangement of 7 x 2 above the mudline. Below mudline, the caisson had a cell arrangement of 9 x 4. A structural transition was made between the 7 x 2 and 9 x 4 cell arrangements with buttress walls. All cells were flooded, as underwater openings were included in the original caisson walls to equalize the hydrostatic pressure. Figure 2 shows the caisson layout with limits for mechanical demolition and for the implosion."

Jan 1, 2016

By Y. J. Cao

The purpose of this study was to investigate the flotation behaviour of unburned carbon in a cyclonic-static microbubble flotation column (FCSMC). The ash sample, collected from a power station in Guangdong province of China, was characterized by size analysis, X-ray diffraction, contact angle measurements, and X-ray fluorescence. The effect of the column flotation operating variables on the removal of unburned carbon from the fly ash was systematically studied. The feasibility of separating unburned carbon and ash was determined from the removal rate of unburned carbon (RUC) and loss on ignition (LOI). Within the range studied, the optimum diesel oil dosage was 1200 g/t, abies oil dosage was 600 g/t, pulp density was 20 per cent, superficial gas velocity was 1.4 cm/s, and circulating pressure was 0.20 MPa. The results indicate that the FCSMC technique is effective in removing the unburned carbon from the fly ash, which can be attributed to the generation of microbubbles and the continuous cyclonic circulation method. Under the optimized conditions, a cleaning ash with 2.13 per cent LOI and 94.21 per cent RUC was obtained.

Jan 1, 2012

By M. D. Riegel, P. B. Pizzimenti, E. M. Zamiskie, Britain A. Materek

"The Skanska/Kiewit/ECCO III team (SKE) in association with HNTB was awarded the design-build contract for Phase I of the Kosciuszko Bridge Replacement Project. As lead designer for the SKE team, HNTB was responsible for the design of the Brooklyn Connector which includes construction of approximately 2000 feet of new staged earth-filled embankments utilizing prefabricated modular retaining walls (T-Walls®). The proposed embankments will be constructed adjacent to and beneath the existing Brooklyn Queens Expressway (BQE) viaduct while the existing viaduct remains in service. Critical aspects of the settlement assessment relating to the soils supporting the existing BQE will be addressed, as their behavior drives the deformation of the viaduct. Furthermore, a construction monitoring program was used to enable the designer to assess settlement predictions and allow SKE to mitigate potential impacts to the existing BQE during construction. Additionally, the methodology for installation of the embankments in a limited access area underneath an active viaduct supported on settlement sensitive shallow foundations will be presented.INTRODUCTIONSkanska-Kiewit-ECCO III Joint Venture, in association with HNTB was contracted by the New York State Department of Transportation (NYSDOT) to design and construct the Phase 1 replacement of the Kosciuszko Bridge Design-Build Project. Phase 1 of the project involves the design and construction of the new eastbound structures of Interstate 278 over Newtown Creek from Brooklyn to Queens. The project runs between Morgan Avenue in Brooklyn and the Long Island Expressway Interchange in Queens (approx. 1.1 miles) and includes the staged demolition of the existing structures."

Jan 1, 2016