No, I worked in "material handling" designing (and selling) manufacturing processes. Everything from simple conveyor systems to fully automated storage and retrieval systems (warehouses run totally by robotics).
I know it isn't mining, but
most engineers & design people have a staff of helpers to expedite the process. Usually the head guy is juggling multiple projects and double checks the work done by his subordinates. Then when the package (drawings & reports) are ready, he signs off on it.
It's a common practice in industry. (unless the project is some cutting edge development, then he usually does more of the work himself.) This should be a slam dunk for Ausenco. That's why I think it can be done by the 'helpers' with only oversight by the head guy.
Ficoce points are valid. The testing will take longer than the design.