Heart of the Mountain

The Heart of the Mountain is a new feature in the Dwarven Mines update. Which unlocks more levels by getting EXP for it will let you use more abilities and perks. It's a kind of skill tree that unlocks new pickaxe abilities. It requires 15 to use. Blocks of coal are abilities while the normal coal are perks. You can only use one ability at a time (they do not stack). In order to unlock more skills, you need to use Tokens of The Mountain, which can be obtained by increasing the tier of the Heart of the Mountain.

Tiers
To level up the Heart of the Mountain, players can complete commissions from the King of the Dwarven Mines, and take part in events which occur every 20 minutes. The first 4 commissions players complete every day will give significantly more HotM experience.

More info needed.