As outlined by standards and guidelines for quantifying mineral resources and reserves, key variables such as brine volume and grade, aquifer geometry, hydrogeologic unit, effective porosity, specific yield, flow rate, and recoverability are used in order to meet the definition of reasonable prospects of economic extraction and to define the mineral resource. Conversion of status from a mineral resource to a mineral reserve requires modifying factors ranging from mining methods, to processing strategies, to environmental, social, and permitting aspects of the project.
Production wells in deeper deposits, or extraction trenches for shallower systems, are generally the mining methods for extraction of brine resources. Hydrogeologic methods are thus critical to evaluating what portion of a defined mineral resource is economically extractable and can in turn be defined as a mineral reserve. Consistent with industry guidelines, we use the technical reporting terms “Drainable” and “Extractable” as factors for evaluating and advancing project status from mineral resource to mineral reserve. These hydrogeologic modifying factors are in part supported using exploration results, aquifer testing, conceptual modeling, and hydrodynamic numerical modeling methods simulating wellfield or trench extraction for mining the lithium-enriched brine.