Tropico 5

This trophy will almost surely be obtained naturally during your campaign but if somehow you missed it start up a sandbox game with unlimited money and no disasters and on a large map. Now find suitable mining sites and make sure they're all connected to roads and a construction office. It will take a short while before you have mined the needed number so just keep playing the game but make sure you do just enough to keep people happy so you keep winning elections and that your government doesn't get overthrown by rebels.