Swelling and osmotic flow in a potential host rock

2007 ◽  
Vol 32 (1-7) ◽  
pp. 408-420 ◽  
Author(s):  
S.T. Horseman ◽  
J.F. Harrington ◽  
D.J. Noy
Keyword(s):  
Host Rock ◽  
Potential Host ◽  
Osmotic Flow

scholarly journals Characterizing mineralogy and redox reactivity in potential host rocks for a UK geological disposal facility

2015 ◽  
Vol 79 (6) ◽  
pp. 1353-1367 ◽  
Author(s):  
J. Quirke ◽  
C. M. B. Henderson ◽  
R. A. D. Pattrick ◽  
K. M. Rosso ◽  
A. Dent ◽  
...  
Keyword(s):  
Iron Content ◽  
Host Rock ◽  
Azo Dye ◽  
Total Iron ◽  
Geological Disposal ◽  
Potential Host ◽  
Fine Grained ◽  
Reducing Conditions ◽  
Redox Reactivity ◽  
Host Rocks

AbstractGeological disposal facilities (GDF) are intended to isolate and contain radioactive waste within multiple protective barriers, deep underground, to ensure that no harmful quantities of radioactivity reach the surface environment. The last line of defense in a multi-barrier GDF is the geosphere, where iron is present in the host rock mineralogy as either Fe(II) or Fe(III), and in groundwater as Fe(II) under reducing conditions. The mobility of risk-driving radionuclides, including uranium and technetium, in the environment is affected significantly by their valence state. Due to its low redox potential, Fe(II) can mediate reduction of these radionuclides from their oxidized, highly mobile, soluble state to their reduced, insoluble state, preventing them from reaching the biosphere. Here a study of five types of potential host rocks, two granitoids, an andesite, a mudstone and a clay-rich carbonate, is reported. The bulk rocks and their minerals were analysed for iron content, Fe(II/III) ratio, and for the speciation and fine-grained nature of alteration product minerals that might have important controls on groundwater interaction. Total iron content varies between 0.9% in clays to 5.6% in the andesite. X-ray absorption spectroscopy reveals that Fe in the granitoids and andesite is predominantly Fe(II), and in mudstones, argillaceous limestone and terrestrial sandstone is predominantly Fe(III). The redox reactivity of the potential host rocks both in the presence and absence of Fe(II)-containing 'model' groundwater was investigated using an azo dye as a probe molecule. Reduction rates as determined by reactivity with the azo dye were correlated with the ability of the rocks to uptake Fe(II) from groundwater rather than with initial Fe(II) content. Potential GDF host rocks must be characterized in terms of mineralogy, texture, grain size and bulk geochemistry to assess how they might interact with groundwater. This study highlights the importance of redox reactivity, not just total iron and Fe(II)/(III) ratio, when considering the host rock performance as a barrier material to limit transport of radionuclides from the GDF.

scholarly journals Application of Geochemical Technique in Exploration and Evaluation of Copper, Lead and Zinc Resources of Nepal

1993 ◽  
Vol 9 ◽  
Author(s):  
B. M. Jnawali ◽  
K. M. Amatya
Keyword(s):  
Base Metal ◽  
Host Rock ◽  
Mineral Exploration ◽  
Soil Sampling ◽  
Reliable Estimate ◽  
Soil Geochemistry ◽  
Potential Host ◽  
Lead And Zinc ◽  
Copper Lead

Application of Geochemical technique in mineral exploration was used in Nepal during 1975-1985 by the Mineral Exploration Development Board (MEDR). Systematic drainage reconnaissance over 40,000 km2 area resulted in the recognition of a large number of anomalies several of which are related to previously unknown mineralizations. The anomalies were categorized  into  1  to 4   assessed  on  the  basis  of  magnitude,  homogeneity,  area and potential host rock. All anomalies of category 1 and 2 that were investigated by follow-up stream sediment and soil geochemistry of varying stages were finally found to disclose the mineralized sources. In all cases, detailed grid soil sampling results in conjunction with geologic observations enabled to ascertain the location, extent and continuity of sub­ outcropping bedrock source with considerable precision, but it was not possible to make reliable estimate of grade. It has been attempted to evaluate the base metal resource based on the data available of the MEDR work as well as Department of Mines and Geology (DMG) and others. Although no economic deposits have been discovered except Ganesh Himal Zinc Lead, about 20 base metal prospects have been drilled and tonnage and grade proved and estimated. Of these, Kalitar Copper and Wapsa Copper deposits are considered to be of marginal economic grade, while the rest are inventoried a deposits of subeconomic to non-economic grade.

Tourmalinite as a potential host rock for gold in the Caledonides of Southeast Ireland

1989 ◽  
Vol 24 (2) ◽  
Author(s):  
P. McArdle ◽  
M. Fitzell ◽  
M.G. Oosterom ◽  
P.J. O'Connor ◽  
P.S. Kennan
Keyword(s):  
Host Rock ◽  
Potential Host

scholarly journals Kajian Geologi, Radiometri dan Geokimia Granit Banggai dan Formasi Bobong Untuk Menentukan Daerah Potensial Uranium di Pulau Taliabu, Maluku Utara

EKSPLORIUM ◽  
2016 ◽  
Vol 37 (1) ◽  
pp. 13
Author(s):  
Ngadenin Ngadenin
Keyword(s):  
Host Rock ◽  
Uranium Mineralization ◽  
Geochemical Data ◽  
Potential Host ◽  
Geological Setting ◽  
Vein Type ◽  
The Future ◽  
Uranium Exploration ◽  
Lignite Coal

Kajian geologi, radiometri dan geokimia granit Banggai dan Formasi Bobong telah dilakukan untuk mendapatkan daerah potensial uranium. Pulau Taliabu dipilih sebagai lokasi kajian karena secara tektonik pulau Taliabu adalah benua mikro pecahan dari benua Gondwana yang terpisah pada akhir Mesozoikum hingga Paleogen. Beberapa tipe mineralisasi uranium terbentuk pada periode Gondwana antara lain adalah mineralisasi tipe batupasir, mineralisasi tipe batu bara lignit dan mineralisasi tipe urat. Pulau Taliabu merupakan serpihan dari benua Gondwana sehingga diharapkan di Pulau Taliabu akan ditemukan mineralisasi uranium atau paling tidak ditemukan indikasi keterdapatan mineralisasi uranium. Tujuan dari kajian ini adalah untuk mendapatkan lokasi potensial uranium untuk pengembangan eksplorasi uranium di masa mendatang. Metode yang digunakan adalah mengkaji data geologi, radiometri, dan geokimia yang berasal dari berbagai sumber. Hasil kajian menunjukkan bahwa data geologi, radiometri, dan geokimia memberikan indikasi positif terhadap pembentukan cebakan uranium tipe batupasir. Granit Banggai berpotensi sebagai sumber uranium. Batupasir pada Formasi Bobong berpotensi sebagai batuan induk. Lapisan batubara dan pirit berpotensi sebagai presipitan. Daerah potensial uranium terletak di wilayah Formasi Bobong dan sekitarnya. Geological, radiometrical, and geochemichal studies of Banggai granites and Bobong Formation have been conducted in order to obtain  potential uranium area. Taliabu island is selected for the study because Taliabu island is a micro continent fraction of the Gondwana super continent that separated at the end of the Mesozoic to Paleogene period. Some types of uranium mineralization formed in the period of Gondwana include sandstone-type, lignite coal types and vein-type. Taliabu island is a small part from the Gondwana super continent so it is expected will be found uranium mineralization or at least indications of uranium mineralization occurences. The aim of this study is to obtain uranium potential areas for the development of uranium exploration in the future. The methods used are reviewing geological, radiometric, and geochemical data from various sources. The results of review showed that geological setting, radiometric, and geochemical data gives positive indication to the formation of uranium mineralization for sandstone type. Banggai Granite is a potential uranium source. Sandstone of Bobong Formation as a potential host rock. Coal and pyrite as a potential precipitant. Potential areas for uranium is located around Bobong Formation.

scholarly journals Potential Uranium Migration within the Geochemical Gradient of the Opalinus Clay System at the Mont Terri

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1087
Author(s):  
Theresa Hennig ◽  
Michael Kühn
Keyword(s):  
Pore Water ◽  
Host Rock ◽  
Multicomponent Diffusion ◽  
Opalinus Clay ◽  
Potential Host ◽  
In Situ Experiments ◽  
Homogeneous Models ◽  
Uranium Migration ◽  
Clay System ◽  
Mont Terri

Transport properties of potential host rocks for nuclear waste disposal are typically determined in laboratory or in-situ experiments under geochemically controlled and constant conditions. Such a homogeneous assumption is no longer applicable on the host rock scale as can be seen from the pore water profiles of the potential host rock Opalinus Clay at Mont Terri (Switzerland). The embedding aquifers are the hydro-geological boundaries, that established gradients in the 210 m thick low permeable section through diffusive exchange over millions of years. Present-day pore water profiles were confirmed by a data-driven as well as by a conceptual scenario. Based on the modelled profiles, the influence of the geochemical gradient on uranium migration was quantified by comparing the distances after one million years with results of common homogeneous models. Considering the heterogeneous system, uranium migrated up to 24 m farther through the formation depending on the source term position within the gradient and on the partial pressure of carbon dioxide pCO2 of the system. Migration lengths were almost equal for single- and multicomponent diffusion. Differences can predominantly be attributed to changes in the sorption capacity, whereby pCO2 governs how strong uranium migration is affected by the geochemical gradient. Thus, the governing parameters for uranium migration in the Opalinus Clay can be ordered in descending priority: pCO2, geochemical gradients, mineralogical heterogeneity.

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