From Guild Wars 2 Wiki
“Throw out a remote-controlled land mine that damages, knocks back, and removes a boon from nearby foes.
— In-game description [?]
- Mines are proximity-triggered, but the engineer may also Detonate them remotely.
- On land, Throw Mine is a ground-targeted skill. Underwater, Throw Mine is a normal use skill, with the mine deploying directly on the player.
- Mines last for 60 seconds, and then disappear.