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Sealing of huge water ingress in headrace tunnel of Uma Oya Project, Sri Lanka
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2020
A. Rahbar Farshbar, A.H. Hosseini
The Highland series rocks cover the whole project area. They include pre-Cambrian rocks formed under high grade metamorphic conditions and are composed of two main types of rocks namely metasediments and charnockites or Charnochitic-gneisses. The metasedimentary rocks are metamorphosed sedimentary rocks and consist of garnet sillimanite gneisses or Khondalites, quartzites, quartz feldspar granulites, garnet gneisses, marble and impure crystalline limestone. Charnochitic gneisses are the most common rock types of the Highland series. Quartzite’s are very hard rocks and difficult to drill through. Marble and impure crystalline limestone may ran into a problem when encountered in tunnels, shafts and dam foundations or across reservoir periphery, especially when associated with faults and karstic zones. The project area is folded into a series of large domes, basins, anticline and syncline structures [Rahbar, A. & Rostami, J. 2016].
Sealing of huge water ingress in headrace tunnel of Uma Oya Project, Sri Lanka
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2019
A. Rahbar Farshbar, A.H. Hosseini
The Highland series rocks cover the whole project area. They include pre-Cambrian rocks formed under high grade metamorphic conditions and are composed of two main types of rocks namely metasediments and charnockites or Charnochitic-gneisses. The metasedimentary rocks are metamorphosed sedimentary rocks and consist of garnet sillimanite gneisses or Khondalites, quartzites, quartz feldspar granulites, garnet gneisses, marble and impure crystalline limestone. Charnochitic gneisses are the most common rock types of the Highland series. Quartzite’s are very hard rocks and difficult to drill through. Marble and impure crystalline limestone may ran into a problem when encountered in tunnels, shafts and dam foundations or across reservoir periphery, especially when associated with faults and karstic zones. The project area is folded into a series of large domes, basins, anticline and syncline structures [Rahbar, A. & Rostami, J. 2016].
Compositional characteristics of mineralised and unmineralised gneisses and schist around the Abansuoso area, southwestern Ghana
Published in Applied Earth Science, 2023
Raymond Webrah Kazapoe, Olugbenga Okunlola, Emmanuel Arhin, Olusegun Olisa, Daniel Kwayisi, Elikplim Abla Dzikunoo, Ebenezer Ebo Yahans Amuah
The Sefwi-Bibiani Greenstone Gold Belt is situated northwest of the Ashanti Greenstone Gold Belt and is underlain by metavolcanic and metasedimentary rocks that are granitoids and mafic units (Galipp et al. 2003; Senyah et al. 2016). The majority of the metavolcanic rocks are massive and pillow basalts, basaltic andesite, dacites, and rhyolites with tholeiitic to calc-alkaline signatures (Perrouty et al. 2012; Senyah et al. 2016). The majority of the metasedimentary rocks consist of phyllites, wackes, and a volcaniclastic unit with pyroclastics and epiclastics (Jessell et al. 2012; Perrouty et al. 2012). The metavolcanics and metasedimentary rocks are intruded by syn-volcanic tonalitic to granodioritic granitoids (Jessell et al. 2012). These granitoids have now been metamorphosed into various gneisses (Kazapoe et al. 2022). The Sunyani Basin is bordered to the west by the Sefwi-Bibiani Greenstone Gold Belt and to the east by the Kumasi Basin (Griffis and Agezo 2000).
Sedimentology in metamorphic rocks, the Willyama Supergroup, Broken Hill, Australia
Published in Australian Journal of Earth Sciences, 2018
B. P. J. Stevens, G. M. Bradley
The GSNSW group formulated an objective classification and nomenclature system for the metamorphic rocks of the Willyama Supergroup (Stevens & Willis, 1983). The aluminous schists and gneisses and their interlayered fine-grained siliceous rocks were recognised as metasedimentary rocks, i.e. metamorphosed sandstones, siltstones and shales rather than just metamorphic mineral assemblages (e.g. ‘sillimanite–biotite–garnet gneiss’). Each layer was recognised as a (metamorphosed) psammite, psammopelite or pelite bed, based on objective criteria, and the mapped units represent various proportions of these beds. The compositions and textures of the very minor layered calc-silicate rocks identified them as metamorphosed carbonate-rich sediments.