By picking them up around the map, you can blow up a passage to get yourself some Supplies.
Considering that you are in a cave, it's not that odd to see TNT laying about. Excavating can be extremely tedious to do, and throwing a couple of explosives will easily lighten the workload.
Although, it doesn't really look like this cave is used for mining minerals. What exactly was this place used for?
- Try and get some survivors to help you find some TNT. The faster you find them, the faster you can blow up the rocks.
- To blow up the TNT, use the trigger box.
- You get 15$ for putting the TNT in the TNT Box.