[LintMan]

I think the mines are only cloaked on the sector display, not in tactical combat. The AI attacked one of my minelayers once, and I pumped out a bunch of mines, which the computer promptly targeted and destroyed.

I don't think mines are useful at all in tactical combat - they don't trigger when enemy ships get near, and even if an enemy ship explicitly rammed one, the mine doesn't do its explosive damage.