The DSN is digging for Iron ore in this Lego Mine created by General Hughes. The Iron Mine is also known as the Jean Douglas Memorial Base inside the DSN. This build is a part of the Decisive Action 4, a collection of Lego MOCs that are creating a fictional world. The whole scene fits in a 20×20 stud base, but expands way up, 3 feet up! In the lower most level is the Ore Transport system responsible for transporting the minerals from tunnel to tunnel. The green LED lighting looks really great here, and helps to highlight the stone/cave design. On the second level is the main mining operation. The green lights being used again to highlight the giant drilling system. The third level reveals that the iron ore is being transported via rockets. The red LEDs help to differentiate this man made level from the lower green lit caves. Finally on the surface you can find the rocket being loaded up with ore from below. A perspective built micro city can be found on the hills, and a brick built background reveals other rockets blasting off.
You can find a lot more information and lore about this Lego DSN Mine over here: https://www.flickr.com/photos/188436807@N05/50017934347/