[mac5732]

what if you tied "dumb mines" to the type of treaties you have with the AI or other players?
If you have trade/trade reasearch/military they would have access thru the dumb mines, other treaties they blow up. I would think if you had trade etc type treaties your partners would have to have access thru your fields or no trade etc could take place. Military similiar in theory or maybe on a restricted basis, possible example, anything up to a CA allowed thru without sometype of sensor, anything bigger it goes '"boom". You could make it that you would have to "gift" them the tech in order for them to get thru the mine field or something on that order.

just some ideas mac