Well, my concept is that it should also be able to take out missiles, so someone with one of these things could cool down a missile fight to some extent fairly quickly too, but they'd be extremely ammo-limited. On the other hand, I also think that mines should persist. Having objects (other than player ships) suddenly disappear because someone logs off or leaves the sector doesn't make much sense to me. This could create some interesting situations where such a demining weapon may only just be enough. Especially if we eventually get the ability to hire bots and program them to do simple things and/or more scattered mine deployment.

That is to say, 500m is wide enough to fly through, but it's not very deep either. :)