Couple things I noticed. It looks like they are about to or have already done some trench work because those large rectangular green things in the next to last video are used to shore up the walls of a trench so that someone can safely work in it without fear of it caving in on them. How they work is you use two of them connected with a few pipes (they slide into the big metal rings). then you can simply lower this into the trench. They are often used to do storm drain work or something similar where a moderately deep narrow trench is needed. Also in the last video you can see multiple pieces of storm drain. It looks like they might be working on the drainage system under the mine train, so hopefully that shows some progress in that area.