Interpretation and application of hydrogeological concepts to commercial-scale brine extraction projects

Author(s): 
Pablo Cortegoso, Terry Braun, Vladimir Ugorets, Cristian Pereira
Date: 
Wednesday, May 18, 2016
First presented: 
Water in Mining 2016
Type: 
Published paper
Category: 
Civil Engineering
Water Management

Brine extraction for surface process and recovery of potash, lithium and industrial salt requires the application of traditional hydrogeological theories to hyper‐saline solutions. Such brines present additional technical challenges in comparison to fresh water due to density effects (e.g., 1.2 gram/cm3), density driven multi‐chemical composition flow on a large scale, and interaction between brines and fresh water over the course of the production period. Surface production facilities require estimation of brine composition over time. Therefore, the hydrogeologist is tasked with balancing extraction rates from multiple production wells, locating the production wells in space (and time), predicting chemical composition of the pre‐pumping and extracted brines and monitoring depletion of a “dynamic” resource. Each of these parameters can have a significant impact on project economics. The parameters such as effective porosity, permeability (“hydraulic conductivity” adjusted by density and dynamic viscosity), anisotropy, aquifer configuration (extent, thickness and heterogeneity), and wellfield efficiency are key in the estimation of resources and reserves for a brine extraction project. During the stages of prefeasibility and feasibility, an accurately built numerical groundwater model is required in order to develop a production plan. Recent guidance from the Ontario Securities Commission provides an indication of how to disclose brine resource and reserve estimates according to the Standards of Disclosure for Mineral Projects, namely National Instrument 43‐101. This paper examines the technical aspects of estimating extractable brine resources and reserves, and current public disclosure guidance.

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Feature Author

Pablo Cortegoso
Pablo Cortegoso is a Civil Engineer with over 8 years of experience in civil and mining projects; specializing in lithium brine projects. His main areas of focus are surface water hydrology and modeling, project management, design and implementation of field programs and data collection and analysis for hydrogeological and geotechnical studies. Mr. Cortegoso has extensive experience in hydrogeological field programs, with an emphasis on lithium brine deposits, including well designs, packer testing and aquifer tests. Mr. Cortegoso expertise includes solar pond evaporation design, modeling and operation for lithium and potassium brine projects. Mr. Cortegoso has been a key member in the preparation and completion of Technical Due Diligences, Technical Reports (Mineral Resource and Reserve Statements), Preliminary Economic Assessments, Pre-Feasibility and Definitive Feasibility Studies in accordance with NI 43-101 and JORC Guidelines for lithium brine projects throughout Argentina, Chile, USA, UK and Botswana.

 

Lithium Project Development Specialist
MSc Civil Engineering
SRK Denver
Terry Braun

Terry Braun has over 25 years of professional experience in mining and environmental projects. His practice incorporates various elements of environmental compliance activities as well as engineered solutions to potential environmental liabilities at mining and other industrial operations. He develops and often implements projects that require negotiations with regulatory agencies and other stakeholders to achieve client objectives. Terry leads multi-disciplinary project teams tasked with producing engineering studies in accordance with public disclosure requirements (i.e., Canada and U.S.) as well as internal due diligence reviews on behalf of clients. His project experience includes planning, permitting and implementing the large-scale closure program for the BHP Copper San Manuel mine and plant sites in Arizona. He has also led teams in mitigating legacy mining impacts at active and inactive mine properties in the western U.S.

Principal GeoEnvironmentalist
MSc, PE
SRK Denver
Dr. Vladimir Ugorets

Dr. Vladimir Ugorets, Principal Hydrogeologist, has more than 35 years of professional experience in hydrogeology, developing and implementing groundwater flow and solute-transport models related to mine dewatering, groundwater contamination, and water resource development.  Dr. Ugorets’ areas of expertise are in design and optimization of extraction-injection wellfields, development of conceptual and numerical groundwater flow and solute-transport models, and dewatering optimization for open-pit, underground and ISR mines.

Principal Consultant - Groundwater Management and Hydrogeology
PhD
SRK Denver
Cristian Pereira
Cristian Pereira is a geologist with more than 15 years of experience executing projects in the area of hydrogeology in Chile, USA, Canada, Colombia, Phillippines, Mexico and Argentina, with emphasis in conceptual and numeric modeling, as well as evaluation of underground water resources, mine dewatering requirements, environmental impacts of mining, pit lake infilling, brine extraction and pore pressure analysis. He has experience in field work, including control of Barber and Reverse Air type drilling, regional and local geological mapping, design and supervision of long and short duration pumping tests, and work with instruments with pressure transducers. He is skilled in the preparation of interpretative and compilation reports, management and creation of data bases (hydrological, bibliographic) and logistics. He has experience with hydrogeological interpretative software (Hidrochem, Aquifer Test, Aquasolve, among others), of Hydrogeological Modeling (Visual ModFlow and FeFlow) and geographic information systems (MapInfo).
Senior Hyrdogeologist
SRK Denver
SRK Turkey