Pre-feasibility studies are detailed studies that involve the use of metrics and data specific to the project under consideration. Employment of project specific metrics is actually what sets them apart from preliminary economic assessments (PEA), or scoping studies, which are generally based on industry standards rather than derived from detailed site-specific data. For instance, in a pre-feasibility study, the intricacies of the processing methods will be based on initial metallurgical studies of the mineralization in the deposit in question, not standard industry methods.
Pre-feasibility studies usually include a range of options for the technical and economic aspects of a project and are used to justify continued exploration, to complete the required project permitting or to attract a joint venture partner. The overriding aim of a pre-feasibility study is to select the preferred option, also known as base case scenario, for the project development, which commonly factor in mine access, mining and processing methods. This base case scenario is then developed in sufficient detail to underpin decisions to devote any additional funds required to move the project through subsequent stages of development and to a final feasibility study.
By the time a decision is made to proceed with a pre-feasibility study, a preliminary mineral resource report has been finalized and an orebody model demonstrating its shape, tonnes, and grade is available. A thing to note about pre-feasibility studies, however, is that a resource cannot be converted to a reserve unless it backed up by at least a pre-feasibility study.
Lastly, owing to the highly technical nature of the term it’s useful to consult some official geo-speak coming from National Instrument 43-101 for the Standards of Disclosure for Mineral Projects within Canada, which describes a pre-feasibility study as a “comprehensive study of the viability of a mineral project that has advanced to a stage where the mining method, in the case of underground mining, or the pit configuration, in the case of an open pit, has been established and an effective method of mineral processing has been determined, and includes a financial analysis based on reasonable assumptions of technical, engineering, legal, operating, economic, social, and environmental factors and the evaluation of other relevant factors which are sufficient for a qualified person, acting reasonably, to determine if all or part of the mineral resource may be classified as a mineral reserve”.