I've noted some further remarks with respect to PEA/PFS guidelines on SI. The subject matter is very complicated, and I am not willing to lead a workshop on the subject.
I will attempt to simplify the issues, as an entry point for this complex subject matter. I would like to caution readers, however, that simplification inevitably leads to the loss of validity.
http://www.cim.org/~/media/Files/PDF/Subsites/CIM_DEFINITION_STANDARDS_20142
Clicking on that link will automatically download the latest update of the CIM standards, which are incorporated automatically into 43-101 (incorporation by reference).
Here's my simplification. A PEA is based on finding comparable projects, and assuming similar costs and engineering solutions. It is a hypothetical model of an actual mine, but is not based on data obtained about the project location itself.
A PFS is based on actual engineering data obtained from assessments of the potential mine location itself. These categories of data are detailed in the section under the heading "Modifying Factors". You'll have to read the whole document, including the italicized parts, to get a sense of what those modifying factors are, and how they're assessed. The goal is to assess a specific project, based on its unique economic influences.
Ultimately, a PEA and PFS are as different as apples and oranges. They are each based on different information, and serve different purposes.
Lar
