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By Dan Brown

This paper presents a case study of a cyclic lateral pile load testing program performed on two 18-in square prestressed concrete piles (PSC) in Savannah, Georgia. The load test program was developed to simulate the lateral behavior of a single pile under seismic loading conditions for the design and construction of a large LNG storage tank. The lateral load tests included cyclic loading to measure possible degradation in soil response followed by static loading to large displacements (around 6 inches at the loading point). The lateral load was applied through a reciprocating jack positioned to push and pull the piles against each other. The test piles were instrumented with multiple displacement transducers, downhole inclinometer, and strain gauges. This paper provides an interpretation of the test results regarding the pile performance and soil response to monotonic and cyclic lateral loading. A backfitted computational model of the soil resistance was developed to match the test results using the LPILE computer program. The load-deflection and deflection/moment versus depth comparisons suggest that this model appears to capture the behavior relatively well within the general range of suitability for design purposes. New design curves were developed based on the soil parameters derived from the lateral load test results.

Jan 1, 2003

By Mark A. Willian

The purpose of this short paper is to present soil profiles and basic soils information for the portion of the I-880 Replacement Project alignment where highway structures are to be built. The information presented here is derived primarily from foundation investigations conducted by the Caltrans Foundation Unit (currently the Structures Foundation Branch, Office of Structural Foundations) and by others under Caltrans direction. The foundation investigation for the I-880 Replacement Project began in May of 1991. The field work was completed in May of 1992 and consisted of 93 rotary sample borings, 11 consolidation sample borings, 6 TEXAM® pressure meter borings, six in-place vane shear borings and 57 electronic cone penetrometer soundings.

Jan 1, 1996

By H. K. Lin

Residual cyanide in cyanidation tailings can be detoxified by its oxidation to cyanate, as in the Inco and Degussa processes. However, cyanate, the product of detoxification and other oxidation processes, may be reduced to cyanide in reducing environments, e.g., deepwater discharge of cyanidation tailings. This study shows that the reduc-tion of cyanate to cyanide occurs and that the reduction rate increases with decreasing solution redox potential. Solutions with lower pH favor the reduction rate. No significant difference was observed between the results of tests prepared with distilled water and seawater, and the presence of cyanidation solid tailings does not show an effect on the reduction. Because cyanate can be reduced to toxic cyanide, causing environmental concerns, the deepwater discharges of cyanidation tailings must be handled carefully.

Jan 1, 2008

Jan 1, 1995

By R. L. Grayson

In 2010, MSHA began holding hearings on a new coal mine respirable dust rule, which proposes a 1.0 mg/m3 standard, a separate 0.1 mg/m3 quartz standard, and the use of single-shift samples for compliance. Small mines largely comprise the ?hot spots? where dust diseases of the lungs increased dramatically over the past decade. This paper presents findings on the feasibility of small mines? compliance with the proposed new 1.0 mg/m3 standard. It gives probabilities of noncompliance by MSHA district, seam height, and selected ?hot spot? counties. Because silicosis and respirable quartz dust appear to be the primary issues related to a recent doubling of the prevalence of dust diseases of the lungs, multiple regression models for prediction of the average total quartz content of compliance samples are given. These findings have significant implications on the need for better dust control methods.

Jan 1, 2012

By C. J. Kirkland

For two thousand years and more, we insular Britons have been grateful for the existence of the narrow strip of water that separates us from mainland Europe. It has given us a sense of security against invaders, though it has been breached many times. The first recorded serious consideration of a fixed crossing of the English Channel was in around 1802, when it was suggested to Napoleon I. The motive was not entirely peaceable and the British Navy, who saw themselves as defenders of our shores, were decidedly unenthusiastic A whole series of imaginative schemes were proposed in the course of the nineteenth century, embracing viaducts, immersed tubes, artificial islands as resting places for the horses which were to draw carriages, as well as mechanically bored tunnels. The first Channel Tunnel Company was formed in 1872, and an application for permission to construct a tunnel was made to the British parliament. A Colonel Beaumont, of the Corps of Royal Engineers designed and constructed a machine which, in around 1882, bored over a mile of tunnel out to sea from Britain which exists to this day.

Jan 1, 1991

Outotec?s direct leaching process is an atmospheric leaching process for sulphidic zinc concentrates. The direct leaching process, based on special leaching reactors developed by Outokumpu, is the most economical way to produce electrolytic zinc. The production scale applications of the process realized so far are in use at Boliden?s Kokkola and Odda zinc plants. A new full-scale application of Outotec?s direct leaching process will be started in 2008 in China. The process is integrated to the existing production plant, replacing part of the old production facilities by modern technology. Besides high zinc extraction the plant expansion and modernization offers also indium recovery, iron precipitation and solution purification processes. The process equipment includes tailor-made reactors designed on the basis of the work and experience of Outotec research center. Keywords: zinc, concentrate, atmospheric leaching, technology, indium, iron precipitation, solution purification, Outotec

Jan 1, 2008

By A. C. Fieldner, W. A. Selvig

For purposes of coal classification it is desirable to know the composition and calorific value of the pure coal substance; that is, of the coal free from its ash-forming minerals. Two methods suggest themselves: (1) To free the coal from most of the ash-forming material previous to the analysis; and (2) to analyze the coal as received and calculate the analysis, with certain more or less arbitrary corrections, to the pure-coal basis. Calculation methods are obviously more apt to give correct results with low-ash than high-ash coals. With coals of unusually high ash it would appear preferable to remove, previous to the analysis, as much of the inorganic matter as possible, by float-and-sink or acid-treating methods. Effect of Ignition on Inorganic Constituents of Coal The need of corrections in calculating analysis to the pure-coal basis is due to the fact that the ash, as determined by ignition, is not the same, in either weight or composition, as the inorganic mineral matter in the coal. On ignition a number of changes occur in the coal such as loss of water of hydration of the shaly material, conversion of pyrite (FeS2) to ferric oxide (Fe203) with evolution of the sulfur as sulfur dioxide or possible fixation of more or less of the sulfur in the ash as calcium sulfate (CaSO4), and decomposition of calcite (CaC03) to calcium oxide (CaO). The amount of sulfur from pyrite which remains in the ash as calcium sulfate depends on the amount of calcite and pyrite in the coal. Certain coals high in both calcite and pyrite show relatively large amounts of sulfate sulfur in the coal ash. The determination of total carbon and hydrogen in coal includes, besides the organic carbon and hydrogen, the carbon of inorganic carbonates such as calcite, and the hydrogen of the water of composition of some of the ash-forming minerals. For detailed discussion of corrections proposed for calculations of coal analyses to the " pure "

Jan 1, 1930

By K. Woo

The increasing move to block cave mining methods (including sublevel and panel caving) to access deeper and lower grade ore deposits as near surface sources become exhausted raises questions as to the extent and magnitudes of caving-induced subsidence as it may affect strain-sensitive infrastructure on surface. Predicting these surface deformations is difficult as they tend to be discontinuous and asymmetric due to large movements around the cave controlled by geologic structures, rock mass heterogeneity and topographic effects. Of further impediment is the sparse number of case histories available, in which actual subsidence measurements are reported to provide guidance and empirical constraints for subsidence calculations. This study reports the development of an exhaustive and comprehensive database of available (i.e. public domain) subsidence data from block cave mining operations from around the world.

May 1, 2009

By C. R. Austin

THE investigation described in this paper deals with the development of high-temperature alloys of the Konel series over a considerable period of time at the Research Laboratories of the Westinghouse Electric and Manufacturing Co. The word "Konel" has been coined to designate a class of alloys which are essentially nickel-cobalt-iron with other elements added, usually in small quantities. Most of these alloys contain titanium, usually about 2.5 percent. The main consideration related to strength at high temperatures but the thermionic characteristics of the alloys was also of considerable importance. It is, however, with the mechanical properties at elevated temperatures that we are herein concerned. Much attention has also been devoted to their age-hardening characteristics. There is little need to stress the utilitarian aspect of this subject, as it has been discussed frequently. Alloys exhibiting superior properties at normal or elevated temperatures rapidly find many suitable applications. There may be some question, however, as to what constitutes a "superior alloy, " or an alloy that may have good service possibilities at high temperatures. The problem is complex and various means have been employed to predict the useful life that may be expected of a material. In recent years the "creep limit" has been used as the best means of evaluation. Such tests necessarily are prolonged and hence collection of data is very slow. In a general survey of many alloys therefore the creep test is not desirable and recourse must be had to much shorter time tests in order more rapidly to select alloys which appear to show promise. For this reason the present survey has been made using the high-temperature tensile test and a bend' test developed by Howard Scott.1 In the tensile test the conditions have been standardized for all tests, so that values obtained are at least comparable, one alloy with another, although the absolute values recorded merely indicate the mechanical properties at the given temperature under a definite rate of loading.

Jan 1, 1931

By Xuan Li

Aluminum slag is generated when aluminum metals are recycled through a smelting process in the presence of salt. There are small amounts of aluminum metals trapped in the aluminum slag. This research aims at evaluating the use of aluminum slag as an expansion agent for the production of lightweight concrete by taking advantage of the residual aluminum metals in the slag. The research identified key elements of producing lightweight concrete products through utilizing various mixture components including sodium hydroxide (NaOH), lime (CaO), cement, and gypsum. The volumetric expansion rate was investigated and the density and strength of the products were determined. The results show that aluminum slag can be utilized for the production of lightweight concrete products.

Jan 1, 2010

By André de Albuquerque Vicente

Observou-se porosidade de Kirkendall em juntas soldadas dissimilares de liga Fe-Cr-Al do tipo 23Cr-7Al, e aço inoxidável austenítico AISI 310 (25Cr-20Ni). Utilizou-se como consumível de soldagem a própria liga Fe-Cr-Al. O processo de soldagem utilizado foi o GTAW. Caracterizaram-se 3 conjuntos de corpos de prova soldados com diferentes energias de soldagem, antes e após o tratamento isotérmico a 1150oC por 936 horas ao ar. Nos corpos de prova tratados termicamente, observou-se a formação de poros bem como significativas variações dos teores de Al nos metais depositados e formação de camada protetora de alumina nas superfícies oxidadas.

Oct 30, 2017

By Gregory A. Stephan

A case history of design, prediction, probe pile driving, and construction of a pile foundation for Building 3 of Waterside at Bay Beach Condominiums located in Fort Myers Beach, southwest Florida, is presented. Site geometry constraints, the presence of a 12.0 ft (3.6 m) deep lake occupying the southern one-third portion of the proposed building footprint, and marginal subsoils provided specific challenges for design and construction of the foundation. The subsoil conditions were explored by performing Standard Penetration Test (SPT) borings and a Piezocone Penetration Test (PCPT) Sounding to depths of 100 ft (30.5 m) within the building footprint. Additionally, borings were performed to envelope the building. Deep foundation alternatives included driven concrete, monotube, and steel pipe pile as well as drilled shaft. Following an evaluation of high structural loads, site-specific constraints, foundation test data from buildings 1 and 2, and preference expressed by the project owner, a pre-cast prestressed concrete (PPC) pile-supported foundation system was selected as an economical and effective foundation approach. Use of an augered cast-in-place (ACIP) pile foundation system was precluded by the project structural engineer. This paper deals with the design aspects and methodologies utilized in choosing and economizing the foundation system. The building foundation was designed for an allowable pile capacity of 40 tons (353 kN) in compression, 1.5 tons (12 kN) in lateral capacity for a deflection of 0.25-in (0.64 cm) and 15 tons (133 kN) in uplift capacity. For the single story extended garage structure, a pile capacity of 27 tons (238 kN) was indicated in compression. As part of the design process, an extensive probe pile driving program was carried out in order to evaluate the pile driving equipment, determine and verify pile capacities, and optimize the production pile lengths. A total of 33, 14-in (356 mm) square, PPC concrete piles were driven within the entire building limits, and dynamically load tested utilizing Pile Driving Analyzer (PDA) as part of the probe pile driving program. Utilization of PDA during probe pile driving helped in predicting pile set-up (i.e., increase in pile resistance with time) as well as reducing the pile lengths by as much as 20 percent. It resulted in variable pile lengths during the production phase. This information was effectively utilized as part of the overall quality control program to install a total of 559 PPC piles (including 33 probe piles) within the Building 3 footprint, including the reclaimed lake area, to depths ranging from 45 to 58 ft (14 to 18 m) below existing ground elevation as part of the foundation support system. Prior to installation of probe or production piles, a termination criterion was established using 1-dimensional wave equation analyses in addition to the design pile embedment requirement. The predicted pile capacities compared reasonably well with the capacities from the CAPWAP analyses for probe piles. This engineered, monitored and tested foundation solution provided a cost effective and satisfactory basis for completion and approval of the foundation work for the building resulted in cost savings over other foundation alternatives for the owner. The building has since been occupied and a recent reconnaissance has indicated that the building foundations are performing satisfactorily.

Jan 1, 2003

By H. L. Gilbert

Improvements in production of high-purity chromium metal by magnesium reduction of anhydrous chlorides and by hydrogen treatment of electrolytic chromium are reported. Hydrogen-treated chromium has been arc-melted, and the arc-melted material has been successfully forged, rolled, and swaged. The material also has been forged at liquid-air temperatures. X-ray and metallographic studies indicate the recrystallization temperature of rolled chromium sheet to be about 750° C. Preliminary investigation of hot-bending characteristics of rolled chromium sheet shows the minimum bending temperature to be about 325° C. The heat resistance of chromium has been investigated.

Jan 1, 1952

By Luis Angel De Montreuil

Ante el problema del tratamiento de minerales complejos, la demanda de eficiencia metalúrgica y bajos costos de operación, el ingeniero busca el apoyo de la mineragrafía como estudio microscópico de los minerales económicos. En ese sentido, el presente texto señala la importancia de la minegrafía -en tanto ayuda a la flotación de los sulfuros valiosos de los yacimientos peruanos. Asimismo determina las propiedades de los minerales con el fin de identificarlos.

Jan 1, 1986

According to the data provided by the most recent European Survey on Working Conditions, roughly 25 per cent of the European working population is exposed to mechanical vibrations for no less than one quarter of the work shift duration, while around ten per cent are exposed for the entire work shift. The occupational exposure to whole-body vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European Directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacturer). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace; actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253.

Dec 6, 2010

By Eric E. Cather

A mineral survey of the Fisher Gulch RARE II area (A5299), Trinity County, California was conducted by the U.S. Bureau of Mines and U.S. Geological Survey. The Bureau of Mines was responsible for detailed examination of mines, prospects, and mineralized zones; the Geological Survey conducted geological, geochemical, and geophysical studies of the area. The area is underlain by the Salmon Hornblende Schist. Tonalite stocks 1.5 mi (2.8 km) to the east and northeast of the area intrude the schist and are closely associated with the nearby nines (Cox, 1967). The mines have quartz veins containing sulfides and gold in shears trending east to north past in the schist and tonalite (Hotz, 1972). Strewn and terrace gravel s occupy most of the drainages, many have yielded substantial quantities of gold.

Jan 1, 1981

By Rocky (Yaokun) Wu

This paper introduces the development and application of a new cable anchor - Cable-Lok for pre-stressed cable bolting in mines. Cable-Lok is a spring-loaded cable anchor suitable for the drill hole diameter of 50 and 65 mm (2" and 2.5") in medium soft rock to hard rocks. The cable anchor is automatically set on installation and the cable can be tensioned immediately to provide active and primary support throughout its length. Post-grouting can be conducted independently. In comparison with the conventional cable bolting, Cable-Lok anchor will greatly speed-up the cable bolting circle and decreases the cost of cable bolting. Cable bolting anchored with Cable-Lok anchor has wide application in mines, e.g. pre-stressed cable bolting in large span drifts and intersections for permanent rock support, or in hanging walls or stopes for temporary support, or cable lace anchoring etc. This paper introduces the principle of pre-stressed cable bolting and the specifications of the Cable-Lok anchor, presented the testing results in laboratory and the application cases in mines.

Oct 1, 2010

By E. J. M. Jahnsen, I. Jauhari, T. Badrujaman, F. A. Stober, B. O. Wasmund, L. R. Nelson, T. Miraza, J. M. A. Geldenhuis, A. Taofik Hidyat

The role of dedicated operational support in the ramp-up and stabilisation of the FeNi-II furnace for ferro-nickel production at PT Antam?s smelter located in Pomalaa, Indonesia is described. The furnace was uprated to 32MW capability in a rebuild performed in 2005. This primarily involved installing a larger transformer, coupled with adoption of HATCH water-cooled copper plate, waffle and flanker coolers with integrated metal and slag tapblocks, HATCH air-cooled copper fin lower sidewall cooling and HATCH vertical sidewall binding system ? ?holddowns?. Following a smooth commissioning period, the progress in attaining the preliminary ramp-up target load of 24MW is described. This initial target was set by Antam, subject to some prevailing smelter equipment constraints, particularly kiln capacity. Stabilisation of the furnace operation is discussed, together with some of the specific commissioning and operational challenges surmounted by the joint Antam-HATCH team. These included: ?Mastering furnace integrity monitoring and operation with copper coolers, especially metal tapblock planned maintenance and repair strategies; ?Transition from traditional ?immersed electrode? to ?brush-arc? mode of operation approaching as closely as possible to the productive ?shielded-arc? mode of operation within existing equipment constraints; ?Reductant selection and control issues; ?Utilising the sophisticated furnace monitoring to provide detailed indication and warning of potentially destructive furnace upset conditions such as Si reversion and CO boils.

Jan 1, 2007

By Richard J. Mainiero, Michael J. Sapko, James H. Rowland III, Marcia L. Harris

All explosive materials produce a cloud of reaction products, the most toxic of which is nitrogen dioxide (NO2). In the study reported here, 4.5-kg (10-lb) charges of blasting agent confined in either thin-wall 10-cm (4-in) diameter galvanized pipe or 10-cm (4-in) schedule 80 seamless steel pipe were detonated in a closed chamber. The detonation gases were analyzed for NO2, nitric oxide (NO), ammonia (NH3), hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), nitrogen (N2), oxygen (O2), and methane (CH4). Data were evaluated to determine the kinetics of the oxidation of NO to NO2. Analysis revealed that the only mechanism for NO loss for the conditions existing in the chamber was the reaction 2NO + O2 6 2 NO2. The rate constant was 2.08 @ 10-38 cm6 molecules-2 sec-1 for the rate equation -½d [NO]/dt = K @ [NO]2 @ [O2] for NO concentrations up to 100 ppm. The rate constant is in agreement with that recommended by Baulch, Drysdale, and Horne (1973).