My most recent experience was with BM14b. An enemy fleet made it through a minefield (using the "soak up damage with plenty of armour" tactic). this left my minelayer fleeing while dropping one or two mines every once and a while. The enemy followed destroying the mines with PD. DUC fire too perhaps. Think of them as helpless units that just sit there. I've done tests where the enemy doesn't have weapons capable of targeting them. It'll chase after the minelayer, directly through mines. If they practically touch they'll go off. Anything further than basically on top of them and they don't do anything.
I'll also mention the mines in the B5W test can use weapons it seems, but we haven't gotten far enoguh for me to test them yet.
Is there anyway to deal with a large number of mines piecemeal? I have a 160 mines and my minesweeper only sweeps for 60. Do I really have to wait for 3 mine sweepers just to deal with them?
You want to wait until you get enough sweepers together. Entering a minefield with fewer sweepers will result in the remaining mines blowing your fleet up.
Under what conditions will SEV not allow me to save a map? I want to save a particular random map, but I forgot to save it when I generated it. Now it won't let me save the map. Does it have to do with the ancient race trait that I have? Or is there a time limit first?