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Saturated hydraulic conductivity of cemented paste backfill / M. Fall in Minerals engineering, Vol. 22 N° 15 (Décembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1307–1317 Titre : Saturated hydraulic conductivity of cemented paste backfill Type de document : texte imprimé Auteurs : M. Fall, Auteur ; D. Adrien, Auteur ; J. C. Célestin, Auteur Année de publication : 2010 Article en page(s) : pp. 1307–1317 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Cemented  paste  backfill  Tailings  Hydraulic  conductivity  Environmental  performance  Durability Résumé : The key design parameters of cemented paste backfill (CPB, a mix of tailings, water and binder) are strongly influenced by its saturated hydraulic conductivity (permeability). However, our understanding of the permeability of CPBs, as well as factors that affect it and its evolution with time, is limited. Hence, a laboratory investigation is conducted to study the hydraulic conductivity of CPBs and develop a model for predicting its evolution with time. The results show that the hydraulic conductivity of CPB is time-dependent. As the curing time increases, the hydraulic conductivity decreases. The permeability is also affected by the mix components. The permeability decreases as the binder content increases or the w/c ratio decreases. Medium tailings with 45% fine particles confer lower hydraulic conductivity to the CPB. The sulphate can have two opposite effects on the permeability of CPBs, contributing to an increase or decrease. However, the magnitude of the influence of the mix components depends on the curing time and is generally more pronounced at early ages (⩽7 days). Moreover, this study demonstrates that the hydraulic conductivity decreases with curing temperature and time for the studied CPBs. However, the effect of curing temperature on the hydraulic conductivity of CPBs is more significant in early age samples (up to 7 days) and depends on the binder type. Furthermore, the mechanical damage can significantly increase the hydraulic conductivity. Finally, the authors propose a simple function for the prediction of the evolution of the hydraulic conductivity of CPB with time. The validation results show that the developed model is able to predict the time-dependent change of the hydraulic conductivity with good accuracy. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001897 [article] Saturated hydraulic conductivity of cemented paste backfill [texte imprimé] / M. Fall, Auteur ; D. Adrien, Auteur ; J. C. Célestin, Auteur . - 2010 . - pp. 1307–1317. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 15 (Décembre 2009) . - pp. 1307–1317 Mots-clés : Cemented  paste  backfill  Tailings  Hydraulic  conductivity  Environmental  performance  Durability Résumé : The key design parameters of cemented paste backfill (CPB, a mix of tailings, water and binder) are strongly influenced by its saturated hydraulic conductivity (permeability). However, our understanding of the permeability of CPBs, as well as factors that affect it and its evolution with time, is limited. Hence, a laboratory investigation is conducted to study the hydraulic conductivity of CPBs and develop a model for predicting its evolution with time. The results show that the hydraulic conductivity of CPB is time-dependent. As the curing time increases, the hydraulic conductivity decreases. The permeability is also affected by the mix components. The permeability decreases as the binder content increases or the w/c ratio decreases. Medium tailings with 45% fine particles confer lower hydraulic conductivity to the CPB. The sulphate can have two opposite effects on the permeability of CPBs, contributing to an increase or decrease. However, the magnitude of the influence of the mix components depends on the curing time and is generally more pronounced at early ages (⩽7 days). Moreover, this study demonstrates that the hydraulic conductivity decreases with curing temperature and time for the studied CPBs. However, the effect of curing temperature on the hydraulic conductivity of CPBs is more significant in early age samples (up to 7 days) and depends on the binder type. Furthermore, the mechanical damage can significantly increase the hydraulic conductivity. Finally, the authors propose a simple function for the prediction of the evolution of the hydraulic conductivity of CPB with time. The validation results show that the developed model is able to predict the time-dependent change of the hydraulic conductivity with good accuracy. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001897

Suitability of bentonite-paste tailings mixtures as engineering barrier material for mine waste containment facilities / M. Fall in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 840–848 Titre : Suitability of bentonite-paste tailings mixtures as engineering barrier material for mine waste containment facilities Type de document : texte imprimé Auteurs : M. Fall, Auteur ; J. C. Célestin, Auteur ; F.S. Han, Auteur Année de publication : 2009 Article en page(s) : pp. 840–848 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Paste  backfill  Tailings  Acid  mine  drainage  Recycling  Barrier Résumé : This study investigates the feasibility of using bentonite-paste tailings (BPT) as a barrier (liner, cover) material for mine waste containment facilities. Improvements of the hydraulic properties are realized by using compaction to densify the paste tailings in the first stage and mixing an additive-like natural bentonite to paste tailings to further reduce the voids that control hydraulic conductivity in the second stage. A significant decrease in hydraulic conductivity is observed with these transformations. Values that are as low as 1 × 10−9 and 4 × 10−9 cm/s are obtained in 8% and 4% bentonite and BPT, respectively. Based on these satisfactory values, additional investigations are conducted to evaluate the freeze–thaw and wet–drying performance of BPT up to 5 and 6 cycles, respectively. The results show that negligible to acceptable changes in hydraulic conductivity occur. None of the changes reach one order of magnitude. As a final step, a cost analysis is undertaken to evaluate the economical benefits that can be obtained from such new material. When compared to conventional compacted clay–bentonite barrier or sand–bentonite with 12% bentonite concentration, it is found that the 4% BPT is less expensive by 66%. The results place this recycled BPT material as a promising candidate for barrier design while reducing the amount of waste to be managed and the cost of surface tailings management. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000685 [article] Suitability of bentonite-paste tailings mixtures as engineering barrier material for mine waste containment facilities [texte imprimé] / M. Fall, Auteur ; J. C. Célestin, Auteur ; F.S. Han, Auteur . - 2009 . - pp. 840–848. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 840–848 Mots-clés : Paste  backfill  Tailings  Acid  mine  drainage  Recycling  Barrier Résumé : This study investigates the feasibility of using bentonite-paste tailings (BPT) as a barrier (liner, cover) material for mine waste containment facilities. Improvements of the hydraulic properties are realized by using compaction to densify the paste tailings in the first stage and mixing an additive-like natural bentonite to paste tailings to further reduce the voids that control hydraulic conductivity in the second stage. A significant decrease in hydraulic conductivity is observed with these transformations. Values that are as low as 1 × 10−9 and 4 × 10−9 cm/s are obtained in 8% and 4% bentonite and BPT, respectively. Based on these satisfactory values, additional investigations are conducted to evaluate the freeze–thaw and wet–drying performance of BPT up to 5 and 6 cycles, respectively. The results show that negligible to acceptable changes in hydraulic conductivity occur. None of the changes reach one order of magnitude. As a final step, a cost analysis is undertaken to evaluate the economical benefits that can be obtained from such new material. When compared to conventional compacted clay–bentonite barrier or sand–bentonite with 12% bentonite concentration, it is found that the 4% BPT is less expensive by 66%. The results place this recycled BPT material as a promising candidate for barrier design while reducing the amount of waste to be managed and the cost of surface tailings management. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000685