I've re-designed them to work a bit better. This is the proxy mine, it first lifts itself up on its legs, drills into the ground and then uses the clamps to force itself into the terrain. Once this is over the mine sits under the terrain. Small parts of the mine still protrude so that enemy craft can see them, but aside from that they are totally un-detectable.
Depending on how good they are, I may make them emit a light and a small beep once in a while, nothing fancy though to give them away.
See the animation here (all hand animated by me

http://www.youtube.com/watch?v=HeOp9SaAm5E