In Boom Beach Mines are used to defend your base against attacks. Unlike other defensive buildings they can be built immediately with no time delay. Mines will detonate as soon as a troop comes within close proximately, causing area effect damage to nearby troops.
Careful placement of mines is essential to use them effectively. If bunched up too closely together they can easily be avoided by other players using flares. Likewise a single mine is unlikely to do significant damage to a group of troops.
One of the best strategies is to spread out your mines a layer two or three deep around your base. This stops troops from being able to avoid walking through them and will usually mean at least two or three mines will damage the troops.
You can use the gun boats artillery and barrage to take out mines before deploying your troops. This is most effective if there are clusters of mines together or when used on Boom Mines.
Upgrading your mines at the Armory increases their damage on detonation.
The table below details the resource cost, damage and upgrade time applicable to mines.