536 resultados para Granite Quarries,


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Mode of access: Internet.

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Mode of access: Internet.

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None published 1891, 1905.

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"An illustrated monthly devoted to the history, story, scenery, industry, and interest of New Hampshire." (Varies slightly.)

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Includes index.

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"A New Hampshire magazine devoted to history, biography, literature, and state progress."

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At head of title: Ministère des travaux publics.

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Imprint varies.

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At head of title Jan.-Dec. 1928: New Hampshire State Magazine.

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The Greater Himalayan leucogranites are a discontinuous suite of intrusions emplaced in a thickened crust during the Miocene southward ductile extrusion of the Himalayan metamorphic core. Melt-induced weakening is thought to have played a critical role in strain localization that facilitated the extrusion. Recent advancements in centrifuge analogue modelling techniques allow for the replication of a broader range of crustal deformation behaviors, enhancing our understanding of large hot orogens. Polydimethylsiloxane (PDMS) is commonly used in centrifuge experiments to model weak melt zones. Difficulties in handling PDMS had, until now, limited its emplacement in models prior to any deformation. A new modelling technique has been developed where PDMS is emplaced into models that have been subjected to some shortening. This technique aims to better understand the effects of melt on strain localization and potential decoupling between structural levels within an evolving orogenic system. Models are subjected to an early stage of shortening, followed by the introduction of PDMS, and then a final stage of shortening. Theoretical percentages of partial melt and their effect on rock strength are considered when adding a specific percentage of PDMS in each model. Due to the limited size of the models, only PDMS sheets of 3 mm thickness were used, which varied in length and width. Within undeformed packages, minimal surface and internal deformation occurred when PDMS is emplaced in the lower layer of the model, showing a vertical volume increase of ~20% within the package; whereas the emplacement of PDMS into the middle layer showed internal dragging of the middle laminations into the lower layer and a vertical volume increase ~30%. Emplacement of PDMS results in ~7% shortening for undeformed and deformed models. Deformed models undergo ~20% additional shortening after two rounds of deformation. Strain localization and decoupling between units occur in deformed models where the degree of deformation changes based on the amount of partial melt present. Surface deformation visible by the formation of a bulge, mode 1 extension cracks and varying surface strain ellipses varies depending if PDMS is present. Better control during emplacement is exhibited when PDMS is added into cooler models, resulting in reduced internal deformation within the middle layer.

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The occurrence of hand grindstones at the Cogotas I archaeological sites is considered to be a common feature. Given that a distant-provenance raw material is frequently involved, determination of its source is a basic factor in the search for a better understanding of resource management and for any Political Economy approach. To progress in these directions an overall study should be planned, using selected grindstones with a view to covering diverse sub-zones of the Cogotas I dispersal area, especially because of its considerable distance from the granite basement source. Such a study may today includes diverse analytical procedures combining successive geographic, petrographic, mineralogical and geochemical criteria. To check the plausibility of the proposed methodology, a preliminary test has been carried out on two granite grindstones, obtained at the archaeological excavation at the Castronuño (Valladolid) Cogotian site, which is fifty km away from an inferred source area that was presumably located at Peñausende (Zamora). The result obtained validates the proposed operational process, yielding a generalizable knowledge to other similar situations.

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A perfuração em maciços rochosos desempenha um papel fundamental na área da exploração e extração de rocha ornamental, nomeadamente em granitos. Para esse efeito, e como irá ser abordado neste trabalho, são utilizados pela empresa Polimagra – Granitos, S.A, nas pedreiras que explora, dois sistemas de perfuração: perfuração hidráulica e perfuração pneumática. Sendo um dos objetivos deste trabalho perceber qual o tipo de perfuração que apresenta maior rentabilidade, torna-se importante perceber as principais características dos dois sistemas de perfuração em estudo. Para isso, com a realização deste estágio curricular na empresa Polimagra – Granitos, S.A, foi possível comparar as principais diferenças dos dois sistemas utilizados, através do acompanhamento dos trabalhos de lavra em pedreiras, da cronometragem de tempos de perfuração em maciço rochoso granítico e da realização de um estudo de fracturação nas pedreiras de Cinza Ariz e Amarelo Macieira. Durante este tempo do estágio foi ainda possível acompanhar os diferentes métodos de transformação utilizado sobre os diferentes granitos obtidos, nas instalações fabris da empresa Polimagra – Granitos, S.A. De destacar ainda, e dentro da área da transformação do granito, a utilização de um sistema robótico de tecnologia de ponta, para corte, acabamento e embalamento de produtos em granito.