My over the road days were back in the 70's and 80's. Never spent much time around Springfield MO., and I never heard of this underground terminal and storage space either. On the top side is Prime's terminal and headquarters. The video is a driver taking a load into the caverns and dropping the trailer. Then he proceeds top side and into Prime's terminal, truck maintenance and parking. This terminal is beyond anything I have ever saw. The underground is an old lime quarry.
Take a look. The video is 15 minutes long. The second link explains the quarry, which is an independent business in itself.

This link is the quarry. It explains how large it is, with over 3 miles of road, underground, and 224 doors for delivery's.