EVALUATION OF IN SITU LEACHING PROCESSES: DUAL-POROSITY MODEL

Abstract

Mineral Resources EngineeringVol. 08, No. 02, pp. 205-225 (1999) No AccessEVALUATION OF IN SITU LEACHING PROCESSES: DUAL-POROSITY MODELJ. LIU and B. H. BRADYJ. LIUEnvironmental Engineering Research Group, Division of Exploration & Mining, CSIRO, Underwood Avenue, Floreat Park, WA 6014, Australia Search for more papers by this author and B. H. BRADYFaculty of Engineering and Mathematical Sciences, The University of Western Australia, Nedlands, WA 6907, Australia Search for more papers by this author https://doi.org/10.1142/S0950609899000220Cited by:1 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractA dual-porosity model is developed to study processes of in situ leaching. The model involves two overlaying continua at the macroscopic level: a permeable fracture system that determines the flow field of leach solution and a relatively impermeable matrix system that determines the leaching kinetics. The most obvious advantage of the model is that parameters it requires are minimal and easily available in practice. These parameters include the in situ hydraulic conductivity, longitudinal and transverse dispersivities, the lumped rate constant, and an empirical rock mass classification index, RQD (Rock Quality Designation). The simulation of in situ leaching processes is linked to RQD through the effective porosity of fractured media. The incorporation of RQD enables the simulation of in situ leaching processes to be carried out for a whole spectrum of ore deposits. When RQD approaches 0, it represents that the ore deposit may be a porous medium with a high effective porosity. This may reduce the double-porosity model to a single porosity model. When RQD approaches 100, it represents that the ore deposit may be considered as impermeable and unleachable. These values bound the possible ranges in behavior of the system. Based on the double-porosity model, the relation between particle size and leachability is developed, and the effects of double porosities on the concentration of a dissolved mineral are investigated. It is demonstrated through model results that the recovery rate of a valuable mineral is mainly determined by the effective porosity of the fracture pore system, the porosity of the rock matrix system, and their ratios in addition to the concentration of reagent and the ore grade.Keywords:Leachingmodeleffective porosityRQDflowtransport FiguresReferencesRelatedDetailsCited By 1Kinetics and mechanisms of leaching of rare earth elements from secondary resourcesJamal Ait Brahim, Sara Ait Hak, Brahim Achiou, Rachid Boulif and Redouane Beniazza et al.1 Feb 2022 | Minerals Engineering, Vol. 177 Recommended Vol. 08, No. 02 Metrics History KeywordsLeachingmodeleffective porosityRQDflowtransportPDF download