What is the basis for that statement? What price point would be used to determine if it were 'economical to produce'? Where in the rule change is this stated, especially in light of probable and possible reserves?

"Where in the rule change is this stated, especially in light of probable and possible reserves? "

this is not stated in the rule change, but is in the basic definition of proven reserves. wrt possible oil shale reserves i suppose someone could call them possible reserves, based upon estonia, but imo, that is even a stretch. i dont think anyone gives any credibility to possible reserves anyhow.