Look for console-like thingys near the gates they can be manipulated top open the gates. The trouble is there is no description when your cursor is over them (unlike chests and shelves) so you'll have to watch the cursor to see if it changes shape. Once you know what they look like, you'll be ok.
If you defuse the mines you can reuse them or sell them. I never liked them much so I sold most of them. I didn't have a high enough traps skill to defuse the mines at Rock Falls but I went back later and retrieved them when Stevie had 80% traps.
Of course there's always the plan B (i.e. blow everything up) method - just shoot the mines to set them off (takes a lot of ammo if you haven't powerful guns).
Red
