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Geomorphology and Flooding
Published in Saeid Eslamian, Faezeh Eslamian, Flood Handbook, 2022
Giovanni Barrocu, Saeid Eslamian
The inorganic component of soils, representing the final stage of weathering, mostly consists of residual products such as iron and aluminum oxide clays, and quartz, very resistant to chemical attack. Weathered rock in situ is named saprolite, of which the characteristics primarily depend on climate, rock type, and time. Its thickness reveals the long-term balance between weathering and erosion. The surface deposits of various characteristics lying over the bedrock constitute an overburden of rock-waste, termed regolith, of various extension and depth. The regolith of different types passes gradually downwards from soils of different profiles through a zone of shattered and partly decomposed rock, named subsoil, to the parental bedrock.
Twin tunnels excavated in mixed face conditions
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2020
M.A.A.P. Silva, F.L. Gonçalves, A.A. Ferreira, H.C. Rocha
As described by Oliveira et al. (2017), this saprolite (and some residual soils) has usually stiff to hard consistency and, thus, requires high amount of liquid addition (very liquid foam or water) in order to give it some plasticity. However, according to Hollman & Thewes (2012) clogging tendency methodology (Figure 2), adding liquids will take this material to the strong clogging tendency field and, thus, it will increase the probability of needing a hyperbaric intervention to clean the cutterhead.
Mineral exploration
Published in Odwyn Jones, Mehrooz Aspandiar, Allison Dugdale, Neal Leggo, Ian Glacken, Bryan Smith, The Business of Mining, 2019
Odwyn Jones, Mehrooz Aspandiar, Allison Dugdale, Neal Leggo, Ian Glacken, Bryan Smith
Saprolite, or moderately to highly weathered rock, is a common geochemical sampling medium being sampled in shallow drilling programs, as it is likely to reflect the chemistry of the bedrock it is derived from. In saprolite, however, depending on conditions of weathering, some ore and pathfinder metals may have been leached out. Due to this, saprolite should be sampled through its depth extent, which is generally done as composite samples every 2 to 4 m. Saprolite can be divided according to its degree of weathering or oxidation into upper or lower saprolite or fine or coarse saprolite, and these zones can also be specifically sampled. An end of hole (EOH) sample is taken from the least weathered rock or saprock.
Geotechnical properties of residual soils from the North-east of Argentina
Published in International Journal of Geotechnical Engineering, 2019
Gustavo O. Bogado, Hugo O. Reinert, Franco M. Francisca
Vargas (1974) proposed a weathering profile for residual soils from Brazil derived from granite, gneisses and basalts. The author defined the upper soil layers as ‘mature residual soils’ what it is now known as lateritic soils and the soil layer below it as ‘young soils’ or saprolite. The term lateritic soil and saprolite were adopted during the International Conference on Tropical Soils in 1985. Saprolite refers to that part of the weathering profile where the soil largely preserves the microfabric and volume of the parent rock (Aydin 2006; Lacerda 2010; Pineda, Colmenares, and Hoyos 2014).The criteria for soil to be described as saprolite is (Wesley 2010): (a) it is soils in the geotechnical sense, (b) it exhibits clear inherited structural features that make possible the identification of the parent rock and (c) it is authentically residual, meaning it is derived directly from the weathering of the rock below it.
A model-based estimate of the groundwater budget and associated uncertainties in Bengaluru, India
Published in Urban Water Journal, 2021
S. K. Tomer, M. Sekhar, K. Balakrishnan, Deepak Malghan, S. Thiyaku, M. Gautam, Vishal K. Mehta
The Greater Bangalore Metropolitan Corporation called Bruhat Bengaluru Mahanagara Palike (BBMP) has an area of approximately 741 km2 and lies between 12°48ʹ-13°9ʹN latitude and 77°27ʹ-77°47ʹ longitude. The city core is above mean sea level, on a divide with a roughly North-South axis, with the Arkavathi river drainage westward, and the Ponnaiyar drainage to the East (Figure 1). The climate is classified as ’topical savannah (Aw)’ in the Köppen–Geiger classification system (Beck et al. 2018), with a long-term mean annual rainfall of 820 mm (Sekhar et al. 2017). Monthly rainfall during the study period (January 2016–December 2016) is shown in Figure 1. 764 mm rainfall occurred in 2016, of which 75% was received from May–August. The Arkavati river basin has NNE-SSW and ENE-WSW lineaments, while the Ponnaiyar drainage is along the NW-SE and WSW-ENE fractures. The city is underlain by Precambrian granite and gneiss, weathered to a maximum depth of 60 m, covered by red loamy and gravelly soils. The aquifer system in the larger Bengaluru urban district is a combination of this shallow weathered zone and the underlying hard rock system (CGWB 2011; Sekhar and Kumar 2009). Hard-rock aquifers of this kind are characterized by low hydraulic conductivity (10–65 m2/d) and specific yield (0.005–0.01) and high lateral heterogeneity. Bore-well yields are typically very low, from 0.8 to 5 litre/s. A typical weathering profile is presented in Maréchal, Dewandel, and Subrahmanyam (2004). The saprolite or regolith is a clay-rich material derived from prolonged in situ decomposition of bedrock and is few tens of meters thick. The saprolite can reach a quite high porosity, depending on lithology of parent rock, and generally has low conductivity.
Advanced Review on Extraction of Nickel from Primary and Secondary Sources
Published in Mineral Processing and Extractive Metallurgy Review, 2019
Pratima Meshram, Banshi Dhar Pandey
Saprolite is leached at atmospheric pressure and is a high acid consumer (up to 1 t acid/t ore), which is a drawback compared to the conventional HPAL process. Table 9 highlights the selected literature on the atmospheric acid leaching process for laterite nickel ores.