Has any one considered this? If they were mining deep inside the mine portal vs surface mining then there would be less activity to be witnessed from the outside. So if someone took pictures outside the mine it might look different or not as active as opposed to surface mining. The old blue surface mining equipment may have been abandon because it sucks! New mining equipment can be constructed and then covered with a metal warehouse to protect it. The satellite and surface images would appear not as active as before when they were surface mining.