Well for starters, I don't think you can throw the company who did the study under the bus. How would you feel if you were in their position. Cuu publicly stated they had manpower issues ect. You can't just cook up some story by undermining the company working on the bfs.
What if Elmer phones the company 4 weeks before the deadline and tells them "Hey the mine plan is no good. We have to revamp the whole thing and start from scratch." Tetra Tech "Are you kidding us. That will take months to do. We don't have the manpower to do it on your deadline as we have other projects we are working on now too." Elmer- "What are we paying you guys overtime for then? We got to get it done by Q1. No excuses." TT - "OK we'll try our best" Elmer -"Great, we'll check with you guys again in a couple weeks" Couple weeks later Elmer has a legitimate reason for his delay.