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By M. W. Hildyard, M. O. Kataka

Seismic integration schemes aim to incorporate the rock mass response provided by the historical seismic activity to improve the ability of numerical models to reproduce future response to mining. Up to now, integration schemes considered the events using quasi-static models. This paper presents case studies that consider some of the seismic and modelling issues needed to extend these schemes to include the dynamic characteristics of seismic events. The ultimate aim of an automated integration scheme seems impractical for dynamic modelling. The predictions of the WAVE elastodynamic finite difference program are, however, suitable for modelling limited numbers of events to determine either the near-field velocities and damage or the effect of fractures and excavations on the far-field low frequency response. Les projets d’intégration sismique ont le but d’incorporer la réponse de la masse rocheuse à l’activité sismique historique pour améliorer la capacité des modèles numériques à reproduire la réponse future à l’exploitation minière. Jusqu’à présent, les projets d’intégration étudiaient les évènements avec des modèles quasi-statiques. L’étude présente révèle des études de cas qui considèrent certaines des questions concernant modelage et séismes qui sont nécessaires pour porter plus loin ces projets en incluant les caractéristiques dynamiques des évènements sismiques. Le but final d’un projet d’intégration automatisé semble impraticable pour la modélisation dynamique. En revanche, les prédictions du programme élastodynamique par la méthode des différences finies WAVE sont appropriées à la modélisation d’un nombre limité d’évènements de façon à déterminer soit les vitesses à petite échelle et les dommages, soit les effets des fractures et excavations sur la réponse de basse fréquence à grande échelle. Seismische Integrationsschemata zielen darauf ab, Reaktionen der Gesteinsmasse, die von den Berichten seismischer Aktivitäten stammt, zu inkorporieren um numerische Modelle in die Lage zu versetzen, künftige Antwort zum Bergbau zu reproduzieren. Bis dato betrachteten Integrationsschemata die Fälle mit quasi-statischen Modellen. Diese Arbeit stellt Fallstudien dar, die einige der seismischen und modellierenden Fragen betrachten, die benötigt werden, um diese Schemata auszuweiten, um die dynamischen Charakeristika seismischer Fälle einzuschließen. Das Endziel eines automatisierten Integrationschemas erscheint für das dynamisches Berechnen undurchführbar. Die Vorhersagen des WAVE elastodynamisch begrenzten Unterschiedprogramms sind jedoch verwendbar für das Berechnen von begrenzten Anzahlen von Fällen, um entweder die Nahfeldgeschwindigkeiten und Schaden oder den Effekt von Brüchen und Extraktionen auf der Fernfeld Niederfrequenzantwort festzustellen.

Jan 1, 2003

A Sun SPARCstation based computer network is utilised to store and process mining data at the Macraes Gold Mine. Techbase and Medsystem software running on the SunOS unix platform is used to generate all data plans, sections and other design data required on a daily basis to run the mining operation. The Macraes site is regarded as a fully integrated site where all geological, grade control, exploration, orebody modelling, resource estimation, pit optimisation and mine design is undertaken on site by MacraesÆ professional staff. The methodologies employed are regarded as æstate-of-the-artÆ where computerisation allows the rapid and efficient evaluation of large quantities of mining data by a handful of professional personnel. Ore reserves are estimated using an indicator kriging method and roving cone pit optimisation, a complex process that would not have been achievable in pre-computing days.

Jan 1, 1992

By Fathi Abdrabbo

Open caissons are used for many geotechnical engineering applications. Open caissons may be used as deep foundation elements bypassing weak soils to tip in firm deeper strata, and in rivers and maritime construction to reduce the risk of scour. Open caissons are also used for collecting sewage water through gravity sewer pipe networks or from sewer force mains. In such applications, the design and construction of open caissons require a detailed soil investigation program. In this way, the design and construction plan of an open caisson can be developed with full knowledge of the prevailing subsoil conditions. The engineering and construction techniques are key factors to achieve functional caissons. Based on close observations during construction stages, the current study presents some challenges that were encountered during the construction of two open caissons of internal diameters 20 m and 10 m (65.6 ft and 32.8 ft). This paper describes the procedure followed to alleviate the construction difficulties encountered. Site exploration program and control measures required to satisfy design and construction requirements are crucial aspects. Sinking of open caissons in dense or very dense sands is risky. Incorrect sinking of open caissons may cause extra cost, delay in construction, and harm to nearby structures. Air/water jetting near the cutting edge of an open caisson, outside slurry trench, and/or inside open trench may be used to drive an open caisson downward. Unsymmetrical work around an open caisson may lead to tilting of the caisson. If this occurs, the tilt should be immediately corrected before resuming the sinking process. Improper cleaning of fine materials on the caisson?s excavation bed, and/or inappropriate pouring of underwater concrete may result in a defective concrete seal. The paper contains a series of practical guidelines to assist those intending to use open caissons, and shares good caisson sinking practice with practitioners. Finally, the study aims to understand the difficulties encountered and to anticipate future problems.

Jan 1, 2012

By Craig T. Jones, Zachary Q. Maassen

"Jet grouting is a method of ground improvement that relies on the erosive capacity of high-speed jets to cut and mix the ground in place with a cementitious grout. A continuous return flow of cuttings, called jet grout backflow or spoils, is expelled to the surface during the grouting process. Data from projects completed in Toronto and Ottawa is presented where BOS Solutions’ services provided significant savings compared to the traditional spoils treatment utilizing vacuum trucks for spoils disposal. These traditional treatment methods are cumbersome and expensive by nature. BOS Solutions provided an alternative solution that is environmentally friendly and capable of handling full flow to process these jet grout spoils utilizing a tank system paired with centrifuges and flocculation additives to remove the ground soils and grout product from the spoils slurry. BOS’ process produced a clean water for reuse in the project while reducing the overall waste volume by producing a dry, stackable solid that could be hauled to a landfill. Benefits observed by using the BOS process were disposal waste volumes decreased over 30% and at least a 19% reduction on disposal costs.SCOPE OF WORKJet grouting is a method of ground improvement that relies on the erosive capacity of high-speed jets to cut and mix the ground in place with a cementitious grout. A continuous return flow of cuttings, called jet grout backflow or spoils, is expelled to the surface during the grouting process. The backflow, or spoils, is a mixture of grout, water and soils. Traditionally, the spoil would be collected in in-ground pits and allowed to solidify for a few days prior to hauling to a final disposal site. For the projects completed in Toronto and Ottawa, the jet grouting work was performed at street level, in high traffic congested areas, presenting the challenge of insufficient space for the contractors to process the jet grout spoils in the traditional way. At first, attempts were made of using vacuum trucks to collect and haul the wet spoils to an off-site location where the spoils would be allowed to solidify. However, this method proved cumbersome and expensive due to the high volumes of spoils generated daily and the high number of vacuum trucks required to support the jet grouting operations, respectively."

Jan 1, 2017

By R L. Brathwaite

The gold-scheelite-quartz lodes of the Wakamarina valley were the most productive of the mesothermal gold-bearing areas in the Marlborough Schist. Most of the production came from the Empire City and Golden Bar mines which worked the Golden Bar lode. Only 134 m of its 1800 m strike length are accessible, in the No.2 level of the Golden Bar Mine. A fault has downthrown the Golden Bar Mine section by = 47 m and displaced it left-laterally by 18 m. The lode is a typical ribbon-banded mesothermal vein, averaging c. 1.75 m wide, and enclosing narrow horses of schist country rock. It is composed of bands of milky æbuckÆ quartz with thin laminae of schist. Scheelite occurs in short strings of grains within quartz on the footwall side of the lode and also in small quartz-carbonate veinlets in the foot wall and hanging wall schist. The lode quartz contains only localised traces of pyrite and arsenopyrite. They are more abundant in the wall-rock schist.   The Golden Bar lode lies within a steeply dipping normal fault, which, on its footwall side, is adjacent to a 40 m-wide, shallow-dipping mylonite shear zone. Within 1 m of the lode, the shear foliation has been dragged down to nearly parallel the lode footwall. Wall rock alteration is manifested by a marked increase in K and Rb, which correlate with abundant illite/muscovite and K-feldspar within 2 m of the footwall of the lode. Amphibole, stilpnomelane, and pumpellyite show a progressive decrease towards the lode. As and Sb increase close to the lode, but are at background levels within the lode itself. Enhanced Cr (150-430 ppm) in the quartz, relative to the schists (~40 ppm), suggests that the source hydrothermal fluids passed through and leached mafic rocks, such as the metabasites from the hanging wall of the lode (~400 ppm Cr).

Jan 1, 1995

By N. Kumar, A. K. Dhawan, A. Varughese, S. K. Khullar

Abstract The in-situ stress field is one of the primary parameters influencing the performance of underground structures particularly in the Himalayas where there is strong influence of topography and geology on in-situ stresses. It is always advisable to measure the in-situ stresses, in whatever best way possible. Hydrofracturing is one of the methods by which in-situ stress can be measured. This paper briefly describes details of the concept of Hydrofracturing in arriving at the in-situ stresses of the rock mass at Pancheswar Project. The data obtained from the tests has been analysed, interpreted and the results are presented in this paper. Kurzfassung Das Spannungsfeld an Ort und Stelle ist einer der wichtigsten Parameter, die das Verhalten der Untergrund-Struktur beeinflussen, insbesondere in den Himalayas, wo die Topografie und die Geologie einen grossen Einfluss auf die oertlichen Spannungen ausueben. Es empfiehlt sich stets die Spannungen an Ort und Stelle so gut wie moeglich zu erfassen. Die Hydrofraktur bzw hydrografisches Zerstueckeln ist eine der Methoden, die bei den Messungen der oertlichen Spannungen verwendet werden koennen. Diese Abhandlung beschreibt kurz Einzelheiten ueber das Konzept von Hydrofraktur bei der Bestimmung der Spannungen an Ort und Stelle von der Felsmasse bezueglich des Projekts Pancheshwar. Die gewonnenen Daten aus den Messungen wurden analysieret und ausgewertet. Die Ergebnisse werden dabei vorgelegt. Sommaire Le champ de contraintes in-situ est un des paramèters principaux influencant l’exécution des structures souterraines particulierèment en Himalaya où les forces in-situ sont fortement influencées par les caractéristiques topographiques et géologiques de la région. La fracturation hydraulique est une technique qui permet de mesurer des forces in-situ des massifs rocheux. Cet article décrit brièvement le mécanisme de fracturation hydraulique et présente les résultats de mesure des forces in-situ des roches au site du projet hydroélectrique de Pancheswar.

Jan 1, 2003

By Corale L. Brierley

Accumulations of microorganisms in the in-situ leaching environment are believed responsible for plugging of the orebody and thus decreasing uranium extraction. To assess the contribution of microbial growth to this problem, packed columns of ore and core specimens were leached in the laboratory. Samples collected at four in-situ uranium mining operations revealed pseudomonads, xanthomonads, Bacillus sp. and Micrococcus sp. in numbers of 105 cfu/ml. These microorganisms, inoculated into simulated leaching conditions, decreased permeability in two uranium ores by one order of magnitude in 20 days. Hydrogen peroxide (0.2 g/l) alleviated microbial plugging in the laboratory. Periodic injection of hydrogen peroxide through the production well into the orebody may reduce microbial plugging problems in the field.

Jan 1, 1982

New GSP Trade Status Approved.--President Carter, by Executive Order effective March 30, has approved Generalized System of Preference treatment for imports of nonferrous metal products and other imports from Ecuador, Indonesia, Zimbabwe, Uganda, and Venezuela. As of May 2, Afghanistan and Ethiopia will be taken off GSP status. Under the Generalized System of Preferences, certain imports from developing countries are provided duty-free treatment. A country can lose its GSP status if its shipments of the product exceed $41.9 million or more than 50% of total U.S. imports during the preceding year. However, the President can waive the 50% rule in cases where total U.S. imports of an item in 1979 were less than $1 million. Certain nonferrous imports from Mexico, Peru, Chile, and Zambia are already covered by GSP. Hearings April 10 on International Tin Agreement.--The Fifth International Tin Agreement of which the United States is a signatory, which entered into force on July 1, 1976, will expire on June 30, 1981. A negotiating conference for a Sixth International Tin Agreement will be held under auspices of the United Nations at Geneva from April 14 to May 16, 1980.

Jan 1, 1980

By Paul Voigt, Mike Hourn, Glenn Stieper

Sable Zinc Kabwe Limited ("Sable") is a base metal processing plant, two kilometres south of Kabwe Town in Central Province, Zambia. The region has a rich history in mining and minerals production, being a major lead and zinc producer from the 1900s up to the mid-1990s. In 2006, a copper plant was built at the Sable processing site to treat third-party copper and cobalt oxide ores and concentrates. The oxide leaching plant included whole ore leaching, solvent extraction and production of 8,000 tpa LME Grade A copper cathode. The plant was placed on care and maintenance in 2014, and Glencore Plc ("Glencore") took the opportunity to convert the plant using a minimal budget, to an Albion Process™ plant to treat local refractory copper concentrates unsuitable or uneconomic for smelting. The Albion Process™ plant comprises an M100 IsaMill™ operating in acidic conditions such that raffinate from the downstream process is recycled back to slurry the concentrate delivered to site thus maximising copper tenor in solution and reducing water consumption. The finely ground concentrate feeds an oxidative leaching plant using the existing stainless steel oxide leach reactors converted to Albion Process™ duty by fitting HyperSparge™ supersonic oxygen injectors and gas dispersing agitators. The leached slurry is then directed to the existing solid/liquid separation equipment, and the PLS is then sent to the existing SX/EW plant. The plant also allows for cobalt recovery from the raffinate. The plant was designed based on testwork on regional copper concentrates. The plant was designed to toll treat a range of concentrates, and so the design was flexible With the flexibility of the Albion Process™ being one of its distinct advantages, the plant was ideally suited for tolling regional concentrates. The plant was commissioned and ramped up in six weeks using low-grade Zambian copper concentrate, and produced exclusively LME Grade A copper with over 99% leach recovery in the Albion circuit. INTRODUCTION The Sable Zinc Kabwe Limited ("Sable") process plant is located 2 km south of Kabwe town and 140km north of Lusaka in Central Province, Zambia. In 1902, rich deposits of zinc and lead were discovered with mines and processing plants operating in and around the town until mid-1994. In 2000, the Kabwe Mine tailings dams were sold to Sable, a newly established company, as part of a purchase deal for other plots and facilities. Up until 2004, Sable produced zinc cathodes in an SX/EW plant treating wash plant tailing material. In 2004, Sable was acquired by the South African mining company Metorex Limited ("Metorex"), and in 2006 a copper/cobalt SX/EW plant was built to produce copper cathode from malachite ore supplied from the Democratic Republic of Congo. In 2011, Jinchuan Group International Resources Co. Ltd acquired Metorex and Sable was in turn sold to a subsidiary of Glencore Plc ("Glencore").

Jan 1, 2019

By K. Webb, M. Hohn

"This paper reviews the evolving Ontario mining regime for mining industry-Aboriginal engagement and its apparent alignment with court decisions, domestic law, emerging international norms, mining industry rules, and mining firm-Aboriginal agreements, drawing on publicly available commentary from government officials, the private sector, and Indigenous communities. This paper provides a preliminary analysis of the potential implications of the new regime, especially for the mining industry and Aboriginal communities and, on that basis, discusses possible future developments.RÉSUMÉ Le présent article analyse le régime minier de l’Ontario pour l’engagement entre l’industrie minière et les Autochtones et son harmonisation avec les décisions des tribunaux, le droit interne, les nouvelles normes internationales, les règles de l’industrie minière et les ententes compagnies minières- Autochtones en se basant sur des commentaires, disponibles publiquement, d’officiels gouvernementaux, du secteur privé et des communautés autochtones. Cet article fournit une analyse préliminaire des implications potentielles du nouveau régime, surtout pour l’industrie minière et les communautés autochtones et, en s’appuyant sur ces données, il traite des futurs développements possibles."

Jan 1, 2016

By Keith A. Heasley, Frank E. Chase, Christopher Mark

Deep cover retreat mining (overburden in excess of 750 ft) is an important emerging issue which will intensify in the future as the more easily mined shallow seam reserves are depleted. Analysis of Mine Safety and Health Administration (MSHA) statistics indicates that deep cover pillar recovery accounts for a disproportionate share of the underground coal mine roof/rib fall fatalities and injuries. Past research has shown that previously recommended Analysis of Retreat Mining Pillar Stability (ARMPS) stability factors (SF’s) may be excessive for deep cover pillar design. The objectives of this study were to evaluate the various methods and strategies by which panels, production pillars and barrier pillars are developed and extracted under deep cover, and to develop appropriate design guidelines. In the course of the research, 29 mines in 7 states were investigated to collect panel design case histories. At each mine site, underground geotechnical data were collected on the pillar line in order to document roof rock, coalbed and floor conditions. The analyses indicated that squeezes were the most likely failure mode where the depth was less than 1,250 ft, but bumps predominated in the deeper cover cases. Immediate roof rock quality, the ARMPS SF’s, and barrier pillar stability factors were all found to be important parameters in determining the outcomes of the case histories. Design guidelines, including suggestions for barrier pillars to isolate active panels from nearby gobs in bump prone ground, are also proposed.

By Michael W. Neill, O&apos

Drilling slurry has become an effective aid to the construction of drilled shafts in caving and/or waterbearing soils. Historically, drilling slurry made of bentonitic clay and water was first used in the US in water well drilling as early as 1889. In coastal Texas drilled shaft contractors began using slurry, often made of on-site clay mixed with potable water, in the years following World War II, on a relatively routine basis. This type of slurry was used to "process" boreholes, in which the borehole was drilled "in the dry" until water or unstable soil was encountered, after which water and on-site clay were introduced into the borehole and mixed in place with the auger or other drilling tool. Drilling then continued under a slurry consisting of the uncontrolled mixture of clay and water until the excavation had reached a relatively impermeable and cohesive material. At this point, a steel casing was dropped into the hole and sealed into the lower stratum of impermeable geomaterial (soil or rock). The slurry inside the casing was bailed or pumped out, drilling continued to plan depth in the dry, a reinforcing cage was set in the partially cased borehole, concrete was placed and the casing was withdrawn. Some soil-slurry was undoubtedly trapped between the casing and the borehole wall, but the quality of that slurry was usually of no concern, because engineers of the period usually viewed drilled shafts as nothing more than deeply buried footings. Any unejected slurry would only serve to lower side shearing resistance, not yet considered in design, but would have no effect on end bearing. In the 1960 's the effectiveness of soil-slurry came into question because it was often ineffective in maintaining borehole stability at marginal drilling sites and because the economy of using shaft resistance, in addition to end

Jan 1, 1991

The National Economic Viewpoint? Any substantial project undertaken by private enterprise would normally be subjected to a Discounted Cash Flow analysis of its commercial viability, and would proceed only if the rate of return was judged satisfactory. A 'national viewpoint' analysis attempts to do the same but from the viewpoint of the community as a whole. The objective is to ensure that those projects are undertaken which yield the best return, economic and social, to the nation as a whole.

Jan 1, 1984

By George H. Hope, Steve Ciccone

"The Red Dog Mine is both the largest known zinc reserve and the largest zinc producer in the world. The mine started in 1989, and by 1999 had increased production from approximately 300,000 tonnes per year (t/yr) of zinc concentrate to in excess of 900,000 t/yr. The VIP Mill Optimization Project further increased zinc concentrate production to 1.1M t/yr while improving both product quality and zinc recovery. The Mill Optimization project also addressed a number of issues related to risk reduction: power generation capacity, water treatment capacity and concentrate thickening. The project was faced with numerous challenges, the most daunting of which was the schedule. This US$105M project was executed, from conception to completion, inside of two years. Less than nine months elapsed from concept to delivery of materials and equipment to site. The project also faced a 100-day ice-free shipping window, the challenges of construction in an Arctic environment, and an extremely tight labour market for qualified craft personnel. These challenges were successfully addressed with several innovative approaches to project execution, including an Alliance contracting arrangement between the owner, engineer and contractor; full integration of the team; construction of modules in Anchorage; and fast-track engineering, procurement and construction.INTRODUCTIONThe Red Dog Mine, which began operations in 1989, is located above the Arctic Circle in Northwest Alaska, approximately 145 km north of Kotzebue (Figure 1). An 80-km road connects the mine site to the DeLong Mountain Transportation System (DMTS) port site. Red Dog is the largest known zinc deposit in the world, with known reserves totalling 94.5M tonnes, and is the largest zinc producer with a concentrate production rate of more than 1.1M t/yr.Open-pit mining is by typical drill, blast and load operation using moderately sized mining equipment. Ore is processed through conventional crushing, grinding, and flotation to produce separate lead and zinc concentrates. Filtered zinc and lead concentrates are trucked year-round to the DMTS port site, where they are stored in two A-frame buildings, 330 and 440 m long. A lightering barge system is used to transfer concentrate from the shallow water load-out to deep-sea vessels anchored approximately two miles offshore. Shipping is limited to a 100-day, ice-free window beginning in early July."

Jan 1, 2003

By L. L. Hirst

Liquid fuel oils possess certain advantages over solid fuels. Ease in handling, precision temperature control, and almost complete freedom from ash are among those considered when a liquid fuel is selected for use in industrial processing. In some instances these fuels are desirable because more heating units can e packed in a Given space where space is limited, as on snips. In other cases the' are chosen because of lower actual cost per British thermal unit absorbed, or for control of the flame to increase the capacity of furnaces, as in steel and refining.

Jan 1, 1948

By Henri-Louis Jacob

Le Québec dispose de ressources en silice abondantes et diversifiées, pouvant convenir dans l'ensemble à la plupart des usages industriels. Dans les terrains Paléozoïques des BassesTerres du Saint-Laurent et des Appalaches, les ressources identifiées comprennent les grès quartzitiques purs du Croupe de Potsdam (Cambrien), exploités notamment à Saint Canut au nord de Montréal comme source de sable de silice pour l'industrie du verre; les arénites quartzitiques des Formations de Val-Brillant (Silurien moyen) et de Kamouraska (Ordovocien inférieur) exploitées dans l'est du Québec comme source de fondant métallurgique; les grès friables de la Formation de Guigues (Ordovicien) au Témiscamingue, à partir desquels on produit des sables de silice utilisés notamment en fonderie et en filtration. Dans la province structurale du Grenville, au nord du fleuve Saint-Laurent, les métaquartzites purs du Supergroupe de Grenville représentent une source importante de silice pour la production de silicium, de ferro-silicium et de carbure de silicium. Des veines et amas de quartz ont aussi été exploités un peu partout au Québec comme source de fondant métallurgique ou de silice ultra-pure pour la production de silicium métal. Quelques dépôts de sables naturels, généralement d'origine marine ou deltaïque sont finalement exploités dans la région de Montréal comme source de sable pour des usages n'exigeant pas un produit de haute pureté.

Jan 1, 2001

By Joseph C. Gillen

This paper discusses the design, construction, and performance of the support of excavation system used at The Atlantic Building jobsite. The support of excavation system had to be adaptable to the different conditions surrounding the site. These conditions included support of four historic building façades, including the nine-story Atlantic Building, as well as support of three historic row-houses along two walls. Directly adjacent to the site is the historic Ford?s Theatre and townhouse. Across a 15? alley is the American Immigration Lawyers Association (AILA) Building, and across a 30? alley is the Federal Election Commission Building and another ongoing excavation. Of historical note, these two alleys were the escape route for John Wilkes Booth following his assassination of President Lincoln. With the excavation being 53? to 58? deep, the system included driven and drilled soldier piles, drilled bracket piles, and two modified tangent walls. The bracing included tiebacks, corner braces, wales, cross lot struts, and a specially designed support system for the nine-story façade. The footprint of the excavation included 12 corners and all alleys and streets were to remain open during construction. The performance requirements for system movement at Ford?s Theatre and AILA Building were ½ inches in the horizontal direction. The modified tangent walls were used in these areas to provide stiffness. The soil conditions at the site were fill material on top of a shallow, sandy, silty, gravel layer on top of a deep layer of soft organic silt and clay. Below the silt and clay layer was fine sandy material at the subgrade.

Jan 1, 2006

By F. D. Sutterfield

This study was conducted to provide experimental evidence on the effect of modifications of gasoline front-end composition on the photochemical specific reactivities of automotive emissions. Evaporative and evaporative-plus-exhaust emissions from an automobile operated with four fuels of different volatility and varying levels of C.-C5 olefins were irradiated in a 10040 environmental chamber at three sets of initial hydrocarbon-nitrogen oxides concentrations. Reactivity was measured and expressed in terms of rate-of-NO2 formation and dosages of oxidant, peroxyacetyl nitrate, and formaldehyde. The compositional changes that were necessary in reducing fuel volatility were found to have no significant effect on the reactivity of the emissions. However, replacing C4-C5 olefins with saturated components resulted in sharp decreases in all reactivity manifestations observed for the evaporative emission samples. A lesser influence (of C4-C5 olefin replacement) was found with the composite exhaust-plus-evaporative samples; the effect that was observed could be attributed to the evaporative emission portion of the sample. The data therefore suggest that saturation of front-end fuel olefins had no large effect on exhaust emission reactivity.

Jan 1, 1971

By Tatsunori Matsumoto

In order to investigate the variation of the load-displacement relations of piles in a site, vertical load tests were carried out on 25 small diameter steel pipe piles. Out of 25 piles, 15 piles were close-ended pipe piles attached with a blade at the pile toe and 10 piles were open-ended pipe piles. To carry out these load tests in a short period, two types of rapid load test methods, Spring hammer load test and Falling mass load test, were employed. The load tests of all piles were completed in two days with 180 blows in total. In order to estimate a static load-displacement of a pile, non-linear damping method was used. It is shown from the test results that the performance of the pipe piles such as the ultimate pile resistance and the initial pile head stiffness is improved by re-driving.

Jan 1, 2006

By Donald L. Siebert

This profile study of the commercial secondary aluminum industry examines not only the elements that form the industry but also the technological contributions of each toward industrial growth. Concise descriptions of processing methods trace aluminum scrap from generating sources to marketable industrial and consumer goods. Economic and marketing appraisals are used to illustrate the impact that recent technology has had upon the secondary aluminum industry. Price, supply, demand, competition, and substitutes are selected as components of an economic model of the secondary industry and are used to illustrate the aggregate effects of technological changes. The final section is a conceptual look at the future in which sensitive economic indicators (such as die casting in the automotive and appliance industries) are examined as well as the problems of conserving mineral resources by retrieving secondary aluminum from solid waste.

Jan 1, 1970