Miners

Miners (8 (or 3 in the European version)) are the 2nd least powerful movable piece in Stratego (Not including the spy), but they can destroy bombs, meaning that they can actually defeat half of your opponent's pieces (including other miners). It is generally best to try to save at least some of your miners, as many players will surround their flag with bombs.

Strategies
You should usually try to save at least some miners, but miners also work well for scouting if your strategy involves capturing all of your opponent's pieces. It is generally best to have at least one miner easily accessible by each lane, as players sometimes block off lanes by placing bombs in the front row.