Search Documents

By AIME AIME

ALL technical men who are planning to visit the Century of Progress Exposition in Chicago this summer-and all reports indicate that it will be worth visiting-should try to be there during Engineers' Week, beginning June 26. At that time most of the national engineering societies of the country will hold important meetings in that city. Engineers will thus have an opportunity not only to see the Fair at a time when special programs have been arranged for their benefit, but will have the opportunity to meet their professional brothers and to attend technical sessions of direct interest to them. The A.I.M.E. headquarters will be at the Stevens Hotel, and it will be to the interest of every Institute member who expects to attend the Fair at that time to secure his accommodations as promptly as possible. A request to the Chairman of the Chicago Section, A.I.M.E., or to the Secretary's office in New York, will bring a copy of the program as soon as it is available, together with any in- formation desired about hotel accommodations or other matters. The Chairman of the Chicago Section is J. R. Van Pelt, and his address is Museum of Science and Industry, 1525 East 53rd St., Chicago.

Jan 1, 1933

Drilling has disclosed a sequence of Cainozoic sediments immediately to the west of the Ediacara mineral field containing little or no dolomitic debris in the lower and middle sections, but with gravel beds of dolomite derived from local rocks in the upper part. It is suggested that the lower and middle sequence of Cainozoic strata was deposited over the area of the Ediacara Range, and that this range was uplifted, probably as a horst block, during Quaternary times and was first exposed to subaerial erosion during the upper Pleistocene epoch.Lower Cambrian dolomites with associated stratiform lead mineralization, which formed the target of drilling on the western downthrown block of the Ediacara Fault, were eroded before deposition of Cainozoic sediments.Intense leaching of basal Cambrian dolomites around the periphery of the Ediacara Basin took place during Mesozoic and Tertiary times. This leaching process has resulted in enrichment of copper and lead mineralization in a thick marginal zone of residual clayey material overlain by dolomitic collapse breccia. These zones of leaching and enrichment were preserved under Cainozoic sediments which have subsequently been eroded. The Ediacara Fault appears to have been a major conduit for mineralizing fluids and is the main lineament of the Torrens Hinge Zone. Contemporaneous movements on this fault have controlled rates of depositionand thickness of sediments across the fault during Adelaidean and Cainozoic times. Though latest movements of this fault have been west block down, the predominant movement has been east block down with associated thickening of sediments to the east in the Adelaide Geosync1ine.

Jan 1, 1972

The Northland Peninsula of northern North Island, New Zealand contains a complex and diverse record of volcanism which reflects rapid tectonic changes during the late Cenozoic. The main volcanic associations observed on the peninsula are late Cretaceous- early oceanic crust obducted onto Northland at the end of the Oligocene, Miocene arc-type rocks and Pliocene-Quaternary intraplate basalts. This sucession of volcanic successions can be related to tectonic convergence developing into subduction and followed by a an environment of tectonic tension. While the volcanic activity is ultimately linked to specific tectonic regimes, because of rapid change magmatism was decoupled from the specific tectonic event. This decoupling of magmatism and tectonism appears to be a feature of the zones of plate interaction in the southwest Pacific region.

Jan 1, 1990

By George W. Maynard Maynard

IN this paper I desire to embody the results of some personal observations of the working of the Siemens direct process as I witnessed it for a part of three days at the works of the Siemens-Anderson Company, in Pittsburgh. This preliminary investigation was to have been followed up by one extending over a considerable period of time, and would have embraced analytical and physical tests. Circumstances over which I had no control, resulting in the temporary suspension of work, have postponed the presentation of a complete paper. If the opportunity is afforded me, I purpose doing this at a future meeting of the Institute. To those interested in the development of the process, reference is made to the papers of Dr. Siemens in the Journal of the Iron and Steel Institute for the years 1873 and 1877, and to the paper of our late lamented brother, Holley, in the 8th volume of the Transactions of our own Institute. Dr. Siemens, in the introduction to his paper "On the Manufacture of Iron and Steel by Direct Process," read before the Iron and Steel Institute in September, 1877, says: " In mixing comparatively rich iron ore in powder with about 25 per cent. of its weight of pounded coal, and in exposing this mixture for some hours to the heat of a common stove or of a smith's fire, metallic iron is formed, which, on being heated to the welding-point on the same smith's hearth, may be forged into a horseshoe of excellent quality. The admixture with the ore of some fluxing materials, such as lime or clay, will, in most cases, be of advantage to rid the iron of adherent slag." This is the keynote of the Siemens direct process. Dr. Siemens says further: "If we regard the production of wrought iron from an abstract point of view, we perceive that we have to accomplish two things, viz., the deoxidation of the ore, and the fusion of the earthy matter .mixed with it; and if we calculate the amount of carbon necessary to accomplish this end, we shall find that in using, say, hematite ore, consisting of peroxide of iron with from 10 to 15 per cent. of silica, we shall require barely 40 per cent. of carbonaceous matter per ton of iron contained in the' ore to effect its reduction, and also the fusion of the slag."

Jan 1, 1882

A Devonian metallogenic province is extended northwards from central Queen- -sland to the Burdekin Basin in the Charters Towers Gold and Mineral Field. Devonian sediments of the Burdekin Basin are intruded by mineralised quartz felspar porphyry which occurs as pebbles in Upper Devonian conglomerate. A mineralised volcanic complex lies on the crest of an anticline in Devonian sediments.Red siltstone is slurried and reduced to pyritic hornfels over folded limestone.A thick wedge of volcanogenic conglomerate overlain by marine shale lies on the mineralised rim of an ocean which suffered cataclysmic changes during Late Devonian times.

Jan 1, 1987

By P Vasconcelos, M-F Zhou, X-F Zhao

The eastern part of the Yangtze craton (eastern China ) is marked by a number of medium to small size porphyry Cu-(Au-Mo) deposits. A detailed geochronological study and existing data suggest that these deposits were emplaced in the 144 - 136 Ma interval. They are spatially and temporally related to voluminous mafic and alkaline magmatic rocks ranging in composition from gabbros, syenites, A-type granites and their volcanic counterparts. This indicates that the porphyry Cu-(Au-Mo) deposits in the eastern Yangtze craton were generated in an intra-craton extensional tectonic setting, which is distinctly different from the compressive environment of oceanic or continental arcs of the Pacific Rim where numerous giant porphyry Cu deposits were formed. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By M Begbie, R J. Norris, D J. MacKenzie

The Otago Schist is crossed by numerous deformation zones that formed in the latter stages of metamorphism and uplift of the metamorphic belt. These deformation zones are long (tens of km) linear features at the regional scale, and are generally narrow (km scale or less). Many of these structural zones separate schist domains with different rock types and structural/metamorphic histories. The Hyde-Macraes Shear Zone is one such deformation zone, and this zone hosts the active Macraes gold mine. The Rise & Shine Shear Zone, 80 km NW of Macraes, is also enriched in gold and has been mined historically. Mineralisation in both these shear zones occurred during the transition from ductile to brittle deformation as the schist belt was uplifted from greenschist facies metamorphic conditions. Recrystallisation of quartz and micas in the early stages was overprinted by cataclasis, with sulfide and gold precipitation throughout. Many of the other late metamorphic deformation zones formed under similar greenschist to sub-greenschist facies conditions, with similar overprinting of recrystallisation textures and folds by more brittle textures such as breccias. Under these conditions, originally regionally pervasive deformation at the highest metamorphic grades was evolving towards more focussed high strain zones at lower temperatures and pressures. Shear zones initially focussed fluid flow along microshears and mineral grain boundaries, resulting in 1 to 100 m scale alteration and replacement in the host schist, with only local development of quartz veins. Fluid flow was not controlled by open fractures, and the rate of fluid movement was probably slow and pervasive. After uplift into the brittle regime, the schist belt underwent tectonic extension. Extension was accompanied by development of swarms of steeply dipping veins, with localised mineralised normal faults. Hydrothermal fluid flow throughout this uplift history was a normal consequence of late stage devolatilisation of the metamorphic belt. Hence, all late metamorphic deformation zones should be considered prospective for gold accumulation.

Jan 1, 2005

Tholeiitic metabasalts comprise at least five geochemically distinct mafic volcanic associations of Late Palaeozoic age within the Gympie Province, southeast Queensland. Geochemical features indicate that parental magmas of the various metavolcanic suites were generated in contrasting tectonic regimes, although each of the suites shows some affinities with eruptives from convergent plate margin settings.Basalts from the Highbury Volcanics of the Gympie Group are island arc tholeiites (IAT) formed during an immature stage of eruptive activity in an intra-oceanic arc. They are unique among the analysed metabasites in possessing high Zr/Nb (Zr/Nb - 30) and very high Ba/Nb, and as well as low Ti/V, Ti/Zr and Ti/Y. These features are explicable solely in terms of contributions from a depleted, convecting upper mantle source, and large ion lithophile element (LILE) enriched fluids ascending from subducted oceanic crust.

Jan 1, 1990

By C. R. van Staal, L. R. Fyffe, J. A. Winchester

"The geochemical characteristics of Early Paleozoic volcanic rocks are used to establish the following tectono-volcanic regimes in the northeastern mainland Appalachians: foreland continental rift volcanics; fore-arc ophiolites; island-arc volcanics; back-arc ophiolites; and back-arc ensialic volcanics. A Late Precambrian calc-alkaline magmatic arc bounds the Early Paleozoic volcanics to the southeast.The Precambrian calc-alkaline volcanics of the Caledonian Highlands, primitive Cambro-Ordovician oceanic-arc volcanics of the Eastern Townships, and within-plate Ordovician volcanics of the Miramichi Highlands can be related to a progressive change in mode of subduction from compressional Andean-type in the Late Proterozoic to extensional Western Pacific-type in the Early Paleozoic. The development of marginal oceanic basins in the Paleozoic created a more favourable environment for volcanogenic sulphide deposition, particularly in back-arc areas.The influence of tectonic setting is reflected in the distribution, size and metal ratios of the massive sulphide deposits associated with the volcanic rocks; deposits within intra-oceanic arcs in the Eastern Townships of Quebec average two million tonnes grading 2.2% Cu, 4.0% Zn, and 0.6% Pb, whereas those within a back-arc, ensialic rift near Bathurst, New Brunswick, average nine million tonnes grading 0.6% Cu, 5.4% Zn, and 2.2% Pb."

Jan 1, 1990

By N. M. Steven, J. M. Moore, J. L. Kuyper

Abstract - Mineral exploration and research has led to the identification of four types of tungsten mineralization in the NE-trending, largely ensialic, inland branch of the late Proterozoic/early Paleozoic Pan-African Damara Orogen. The mineralization (mainly scheelite) occurs in a terrane (the Central Zone) that is characterized by multiple deformation, greenschist/amphibolite-facies metamorphism and numerous peraluminous S-type granitic and pegmatitic intrusions. The four major types of scheelite mineralization are (in ascending stratigraphie order of host rock): (1) thin (5 cm to 2 meter) quartz+ plagioclase+ diopside ± scapolite cale-silicate granofels with finely disseminated scheelite (scheelite-bearing granofels; SBG) developed as discontinuous intercalations within the cale-silicate rocks of the Khan, Spes Bona, Oberwasser and Kuiseb Formations (Nosib and Swakop Groups); garnet+ pyroxene ± vesuvianite + scheelite ± fluorite replacement skarns hosted by Okawayo, Karibib and lower Kuiseb Formation marbles in the aureoles of late tectonic, unmineralized leucogranites; metaturbidite-hosted scheelite- (and possibly wolfrarnite-) bearing tourmalinites, both stratiform and crosscutting, in the Kuiseb Formation located in the 'cleavage fronts' of late tectonic granitoids; scheelite-bearing vesuvianite +quartz+ garnet skarnoid rocks (several hundred meters in length) in the calcareous metaturbidites of the upper Kuiseb Formation. These scheelite occurrences were discovered by the follow-up of a large number of tungsten anomalies located during a regional stream sediment sampling program. Detailed mapping, ultra-violet surveys and rock sampling proved to be the most effective surface exploration techniques for locating mineralization; soil sampling and geophysics were of almost no use. The largest, continuous scheelite-bearing skarn of economic interest, Otjua, has a drill-indicated reserve of 250 000 tonnes at 0.53 wt% W03 and 8 wt% CaF2.

Jan 1, 1994

By N. M. Steven, J. M. Moore, J. L. Kuyper

Mineral exploration and research has led to the identification of four types of tungsten mineralization in the NE-trending, Iargelyensialic, inland branch of the late Proterozoic/early Paleozoic Pan-African Damara Orogen. The mineralization (mainly scheelite) occurs in a terrane (the Central Zone) that is characterized by multiple deformation, greenschist/amphibolite-facies metamorphism and numerous peraluminous S-type granitic and pegrnatitic intrusions. The four major types of scheelite mineralization are (in ascending stratigraphic order of host rock): (1) thin (5 cm to 2 meter) quartz+plagioclase+diopside ± scapolite calc-silicate granofels with fmely disseminated scheelite (scheelite-bearing granofels; SBG) developed as discontinuous intercalations within the calc-silicate rocks of the Khan, Spes Bona, Oberwasser and Kuiseb Formations (Nosib and Swakop Groups); (2) gamet+pyroxene± vesuvianite+scheelite ± fluorite replacement skarns hosted by Okawayo, Karibib and lower Kuiseb Formation marbles in the aureoles of late tectonic, unrnineralized leucogranites; (3) metaturbidite-hosted scheelite- (and possibly wolframite-) bearing tourmalinites, both stratiform and crosscutting, in the Kuiseb Formation located in the 'cleavage fronts' of late tectonic granitoids; (4) scheelite-bearing vesuvianite+quartz+garnet skarnoid rocks (several hundred meters in length) in the calcareous metaturbidites of the upper Kuiseb Formation. These scheelite occurrences were discovered by the follow-up of a large number of tungsten anomalies located during a regional stream sediment sampling program. Detailed mapping, ultra-violet surveys and rock sampling proved to be the most effective surface exploration techniques for locating mineralization; soil sampling and geophysics were of almost no use. The largest, continuous scheelite-bearing skarn of economic interest, Otjua, has a drill-indicated reserve of 250 000 tonnes at 0.53 wt5 WO3 and 8 wt% CaF2•

Jan 1, 1994

By Carlos Gonzalez-Rivera

An alternative cooling curve analysis method focused on the experimental determination of the latent heat of phase changes and phase transformation kinetics is proposed in this work. The method analyses the cooling process of a metallic sample, initially liquid that is contained into a cylindrical metallic mold, both of known weight, thermally isolated at its top and bottom. The method is based on an energy balance associated with the experimental measurement of the temperature change of the sample and the mold during their cooling process. From the numerical processing of the cooling curves, are obtained approximate values of the acting global heat transfer coefficient as a function of temperature in order to describe quantitatively the energy exchange of the metal/mold system with its surroundings. These relationships and other experimental data are used to process the cooling curve of the sample and the mold during solidification, in order to obtain the latent heat of solidification.The method was applied experimentally to zinc and tin of commercial purity, initially liquids and contained into stainless steel molds in order to determine its ability to measure the latent heat of solidification. The obtained results suggests that this method shows a good potential to characterize the solidification of metals.

Oct 30, 2017

By Emad Farouz, Ehab S. Shatnawi, Charles Winter

The increasing demand for small deformations and high-capacity drilled shafts without enlarging drilled-shaft diameters has motivated the development and increased use of a base grouting (BG) technique. This technique has been demonstrated to improve drilled-shaft axial capacity, especially for shafts tipped into loose cohesionless soils. To date, there are a couple of documented design methods for estimating the axial geotechnical resistance of base-grouted shafts. However, there is no or lack of research that addresses the lateral response of such shafts. A base-grouted drilled shaft test program was carried out during the design phase of the Wisconsin I-94 Zoo Interchange reconstruction project. The test program included installing and testing one base-grouted shaft and one ungrouted shaft under both lateral and axial loading. Based on test results, it was concluded that the lateral behavior of the BG drilled shaft is significantly stiffer than conventional drilled shaft . Hypothetical method was developed to account for potential increased, however, the method should be verified with more lateral load test.

By Ke Yang

"Drilled shafts are typically used to support structures subjected to large moments at the shaft head. The large moment can produce push and pull forces on the two sides of a drilled shaft. Consequently, the applied moment is partially resisted by the push-pull moment resistance induced from the vertical side shears. This type of push-pull resistance has not been fully recognized in most design and analysis methods. In this paper, a 30 finite element model for a drilled shaft subjected to lateral load and moment is presented and is validated against two field lateral load tests. Based on the 30 finite element model, a parametric study is carried out. It shows that the push-pull moment can resist 18-35% of the applied moment. The parametric study also shows that the push-pull resistance varies linearly with loading eccentricity when the eccentricity is less than the shaft embedment length. A method to estimate the push-pull resistance is proposed based on the results of the parametric study. Then, a new method for lateral capacity prediction is proposed to account for the push-pull resistance. The base shear resistance is significant for short drilled shafts; therefore it is also included in the proposed method. A case study on four lateral load field tests illustrates that the new method could improve the accuracy of lateral capacity prediction when compared with the traditional Broms method.INTRODUCTIONDrilled shafts are typically used to support a variety of structures subjected to large moments. Sound walls, highway signs, traffic signals, high-rise buildings, electrical transmission towers, and bridge piers are examples of cases where lateral loads with large eccentricity would result in high overturning moments on foundations.Current analysis methods for capacity predictions (Broms, 1964a and 1964b; Brinch Hansen, 1961) or deflection predictions (Reese, et al. 197 4) of laterally loaded drilled shafts are based on the lateral resistance of soils and rocks. However, O'Neill pointed out that moments can be partially resisted through the push-pull resistance provided by the vertical side shears due to the rotation of the pile (Reese, 1997)."

Jan 1, 2005

By S. Narasimha Rao

Significant amounts of lateral load may act on pile foundations supporting structures such as transmission line towers, tall structures, bridge abutments, offshore platforms, quay wails, harbour structures and anchorages for water front structures. There were several theoretical and experimental studies conducted on laterally loaded piles in clays to determine ultimate lateral capacity and deflections under working loads. Under a lateral load, a pile deflects in the direction of load application and the soil in front of the pile offers resistance to this movement. The ultimate lateral resistance of a pile can be estimated considering the statics of the pile for a known distribution of soil resistance with depth. In this paper, considering the contributions from both lateral shear drag and frontal passive earth pressure, a method has been proposed to estimate the ultimate lateral capacity of rigid piles in clays. The lateral shear drag has been estimated in terms of adhesion and shape factor. A few load tests were conducted on model piles subjected to lateral loading and these experimental values are used in verifying the proposed method. The reported results obtained from both model tests and field tests were used in support of the predictions made. In all the cases, there is a good agreement between the predicted and measured capacities.

Jan 1, 1996

By Joern Katzer

It is vitally important to any tunnel project to have an accurate and reliable survey control network inside the tunnel for layouts, as-built surveys, and to provide guidance to the tunnel boring machine (TBM). However, the concepts and methodology to provide such a survey network are sometimes not well understood. For example, the first anticipated survey task that takes place during the bidding process is often ignored, which is to provide a comprehensive survey network preanalysis for the surface network and tunnel traverse based on survey statistics that will be used to make informed decisions on the survey requirements and methodology. Instead, these steps are often only vaguely based on previous results and prior tunneling experience. But each tunnel is different, and a solution that worked for one tunnel project might be unsuitable for another. The purpose of this paper is to provide tunnel project engineers, managers and surveyors with the general concepts for tunnel survey methodologies and examines several statistical tools for a basic horizontal and vertical tunnel survey preanalysis. These survey statistics tools provide useful estimates of the expected lateral and vertical tunnel traverse accuracies, but are not a replacement for a comprehensive tunnel network preanalysis. The proposed formulas do not take centering errors into account, are using average distances for each traverse leg, and assume that the survey data is free of outliers in the measurements. It is very important that the estimated instrument accuracy is based on true values that are reflective of measurement precisions that are actually achievable inside the tunnel to provide accurate results.

Dec 1, 2022

By C. E. Dowker

"IntroductionMechanization underground at the Buffalo Ankerite mine in Deloro township, Porcupine district, had reached a high level by 1944, both in equipment available, and in the use of this equipment, for all stoping operations. Power feed leyners and the latest type of stopers for drilling, slushers for moving ore and fill, and tugger hoists for all servicing, did much to halt rising stope costs, and in some cases decreased them. On the other hand, little beyond the use of mucking machines and power feed leyners had been adopted in the effort to reduce level development costs, or to increase the advance per man-shift.Faced with ever increasing level development costs, caused by rising prices of equipment and supplies, coupled with increasing wage demands for less physical effort, it was realized that more mechanization of development work was essential. The objectives of such further mechanization were:(1) Decreased development costs(2) Increased footage per man-shift(3) Less physical effort by development crews, with greater take-home pay (4) A more satisfied and stable labour force"

Jan 1, 1950

By Amalia Giannakou

This paper utilises 3-D finite-element modeling to study the static and dynamic lateral harmonic response of inclined piles, in a homogenous and a non-homogenous soil, modeled as a linear hysteretic medium. The results of a comprehensive parameter study are presented in the form of dimensionless plots of: (a) static and dynamic swaying and rocking stiffnesses and damping ratios, and (b) distribution of internal forces (bending moment, shear and axial force) with depth. These plots can be readily utilised in practical applications and they offer insight on the role of the inclination in the response of flexible piles.

Jan 1, 2006

By Howard A. Perko

Soldier pile and lagging is a conventional means of temporary excavation shoring. Timber lagging design has traditionally been based upon the designer's experience or empirical rules. One such method is the Goldberg Zoino chart used by the Federal Highway Administration. Most of these methods restrict the designer to a consistent soil profile, certain pile spacing, construction grade timber lagging, and limited depth. The methods do not take into account surcharge loads or a variety of other factors that could arise. A designer working outside of ordinary circumstances with unusual loads, varying soil conditions, or alternate lagging materials has difficulty estimating lateral earth pressures. In rigid earth retention systems, lateral earth pressure is generally assumed to be constant along the length of the wall. In soldier pile and lagging systems, the lagging is often considerably less stiff than the steel soldier piles. As the lagging deflects, the soil tends to bridge between the stiffer elements resulting in a lower pressure on the lagging. Several previously published methods by others for determining this reduced pressure are summarized and discussed. These methods typically consist of using a portion of the active earth pressure in several different pressure distributions. A simple theoretical model is presented for determination of lateral earth pressures on wood lagging. The model is based on a three-dimensional "silo" shaped sliding wedge analysis. Results of the model are compared with other published methods. The model compares well with these methods which cover the normal spectrum of design situations. In addition, the model can be used to estimate lateral earth pressures outside typical situations.

Jan 1, 2008

By David E. Albus, Bidjan Ghahreman

A single-family home constructed on the side of a slope in Los Angeles, CA, was subjected to lateral forces due to soil slope creep on the pile foundation supporting the home. Impacts to the property included cracking and separations in the street, retaining walls, exterior concrete flatwork, and decorative concrete features in the rear yard area. The home was supported by concrete piles that penetrated the surficial soil mantle and were embedded in underlying bedrock. However, the home exhibited minor distress that suggested even the home was being affected by soil creep. Selected points on the home were monitored with an optical survey method and manometer over a period of two years to assess if the home was undergoing vertical or lateral movement. Monitoring data indicated the home was in fact moving down slope in a manner consistent with slope creep. As a result, the authors were concerned that continued movement due to slope creep could result in over-stressing of the piles that support the home and ultimately lead to failure of the foundation system. An evaluation was then undertaken to evaluate the behavior of the foundation system due to forces from slope creep. Research was performed during the course of evaluating the conditions to consider various approaches to modeling pile behavior of the piles supporting the home. Some research has been performed to field measure creep displacement of soils and rock in slopes. These previous works have found a diverse behavior of the soil displacement with depth (velocity profile) indicating the process is very complex. An example of various velocity profiles measured in field experiments is depicted in Figure 1. Other research focused on theoretical models of velocity profiles and exhibited similarities to some of the field measured cases.

Jan 1, 2018