The Gold Mine collects gold from an unlimited underground reserve and stores it until collected by the player and placed into a Gold Storage. When the mine is full, production will be stopped until it is collected (or raided by an enemy player).
The production rate and storage capacity depends on the level of the Gold Mine. One can estimate the amount of resources in the mine by looking at the cart at the right side of the mine.
The Gold Mine takes up a 3×3 space.
When you choose to upgrade a Gold Mine, it will automatically collect any uncollected Gold. Note that if your Gold Storage are full at that time, the uncollected gold will be lost! During the upgrade the mine stops producing gold.
Once the Gold Mine is level 5, you can temporarily boost its production with Gems. Spending Gems will double the Mine’s production for 1 day.
When you click to boost the Gold Mine a clock appears for a few seconds.