Actually, it is a pit (or actually digging out of the side of a hill) which produces rip rap, or larger rocks used for stabilization; and also ballast. I am going to say that they are using dynamite to blast the rock of the mountain then scoop it up with the front end loader , transport it via truck to the conveyor and storage/loading bin then into the hopper cars.
However, down the road I may add a crusher (which really is only the size of a truck) so the materials can be made into aggregate for use in concrete and road construction.