Each mine has some objectives, and you can get the rewards when you close the mine. If you complete a mine (all 30 of the shafts unlocked and to lvl 800, plus Elevator and Warehouse to lvl 2400), you will unlock the next Mainland level.
You complete mines down the path to earn different kinds of Gems for hiring Super Managers, and Materials for crafting Super Manager Equipment.
You can also end the Mainland levels early if you decide to. Tap the "End Mine" button and you will be able to exit, but you won't get all the possible rewards.
You complete mines down the path to earn different kinds of Gems for hiring Super Managers, and Materials for crafting Super Manager Equipment.
You can also end the Mainland levels early if you decide to. Tap the "End Mine" button and you will be able to exit, but you won't get all the possible rewards.