You collect Helmets by completing upgrades within your Frontier Mines. The more upgrades you do (and the more Frontier Mines you complete), the more Helmets you will collect.
The more Helmets you have, the higher your position on the Leaderboard.
You collect Helmets by completing upgrades within your Frontier Mines. The more upgrades you do (and the more Frontier Mines you complete), the more Helmets you will collect.
The more Helmets you have, the higher your position on the Leaderboard.