Do dropped mines in BF3 disappear when you die?
Solution 1:
Anti-Tank mines, EOD bots, Mortars, T-UGS and SOFLAM will not disappear upon death.
As of the latest patch, there is a limit of maximum (6) mines per player deployed. Deploying another causes the earliest one in the sequence to disappear.
C4's and Claymores will disappear upon death.
MAVs survive your death, but will always blow up shortly after respawn.
Radio Beacons disappear once you, the deployer, spawn on them. Also, note that as of the latest patch once you deploy a radio beacon, squadmates can no longer spawn on you, only the radio beacon.
Solution 2:
Placed Anti Tank mines do not disappear according to this Gamespot thread. According to thisBF3Blog.com post, though, claymore mines will disappear upon death