Its incredible how big surface mines these days are. A couple of images from the recent Mining Reference Photopack which include an assortment of more than 570 images taken from a variety of strip mines, coal surface mines, open pit mines including big excavators, conveyor belts, vehicles big and small, equipment big and small, mining dumps, dirt and sand stockpiles and environmental shots.

Reference Pack Mining Vol 1:
https://www.artstation.com/a/37043298