Why not spawn a ship or turret, with whatever mesh you want, keep it stationary or mobile using the abilitydeploy ability and put a lifetime on it, say 120 seconds? The ship holds the ability to spawn your mines, then the ship dies at the end of its expiration time from the abilitydeploy ability?
That is what i would do, its less messy and is less complicated.
Sometimes that counts for a lot.
Sometimes it doesnt if it doesnt do what you want.