A very fair question. A PEA if/when produced, would provide an interpretive answer, albeit still lacking the many costs related to the highly variable S&A costs based on a given management team's good or poor choices leading up to and during production, and that would be IF production is even shown to be a feasible pursuit. I would think those that have been developing PGLC's drill results into a NI 43-101 compliant resource estimate, could also fairly easily and fairly accurately guesstimate an informal minimum gold trading value requirement, that would enable them to render a positive PEA.
I see management is instead spending aggressively towards expanding the resource base, as opposed to seeking a less expensive PEA, as a fairly good indicator that the RC mine either needs to increase in scale significantly to become a feasible project, or today's gold value needs to rise to ??/oz before a PEA makes any sense to pursue.
Investors should really be looking for the explorers that have quality properties and enough cash to survive a year or two. Of course, that cash portion could be an easy thing to find via continual share issuance campaigns, but the definition of "quality" could be the trip wire for management here, especially if/while the OS count continues to rise...
Bottom line for me is that if the RC mine in fact cleanly fit into the "quality" mold for potential acquirers at today's PPS for PGLC, due to a brisk M&A pace in the PM space, PGLC should have already announced a LOI with a serious acquirer by now.