Some things to consider..
Freshly laid mines are quite visible, no matter how you try to hide them..
Mines are always laid in a pattern, and that pattern of disruption of the ground
is easily visible.. The longer they are in place, natural weathering of the ground
will make them vanish.. Just like animal tracks.. But it doesn't happen overnight..
Considering the time frame in this game, they should not be "Invisible"..
Mines are an "Area denial weapon", and that would be their effect in game..
Mines are ALWAYS laid in a orderly pattern.. Not only to make them more effective,
but to make it possible to PICK THEM UP.. Range diagrams showing their location,
the borders of the minefield, and listing the Numbers and Types are ALWAYS filed
with the engineer command structure.. So they can be marked on the "Detailed Maps"
used by planners.. (Special Maps we should have for ground Combat)
Love the Idea in General, but IMO, NO MINES WITHOUT SAPPERS!
This should come with an "Engineer Function" in the game..
It's their Gig!
Edit: Also, Mines have NO FRIENDS, just like a Smokin Hand Grenade..