That explains why I see things change from day to day without seeing any activity. Must be a crew from the North and not used to the heat down here. They are not a local crew (or Contractor doing earthwork) as most of their equipment is rented. (even the dump trucks). Since the equipment is rented I figure they want to finish ASAP to avoid additional rental costs.
I wonder if they can get a concrete truck through the tunnel. If not they will have to pump. I guess if they work at night I won't find out.