Rom's minefield worked on the Bajoran wormhole because it was at a fixed point - everyone knew where the wormhole was, how to get there, and how to deploy the mines.
That's not the same as the Borg technobabble conduits - they can open pretty much anywhere the Borg decide to exit into normal space. Obviously they didn't have this technology durin' the events of TNG 'Q Who', 'The Best of Both Worlds, Part One' or First Contact
Don't forget, it took time for the Defiant to lay the minefield across the wormhole's access point, and the mines weren't cloaked until the entire field was ready.
So, how exactly would anyone be able to predict where the Borg would show up, from one vector/origin, and figure it out in time to produce the mines and lay 'em out in a field without detection?