Mines 3

Note that the minefield owner always rolls for the unit moving into the 
minefield so that it's nature is not given away.  (Oh, you rolled a 51 
and I wasn't attacked, so it must have a 50% chance of encounter.)  
Sorry, but no.

Types of minefield:
    Protective.  Easily emplaced and removed, used for close-in 
protection against an enemy's final assault.  Integrated into a company 
or platoon's defensive positions.  Usually fairly shallow and of 
greatly variable density.  A good average might be 50% chance of 
encounter.  May consist only of AP mines, in which case vehicles can 
ignore.
    Phony:  As per type of minefield simulated, except when the 
defender rolls the dice to tell whether or not the unit was attacked, 
it never is.
    Tactical:  Covered in it's own post!
    Nuisance:  Subset of tactical.  Small and irregular, generally 
small.	50% chance of encounter.  For game purposes, tied to a terrain 
feature, eg. "The crossroads between Hill 204 and Hill 402"
    
John M. Atkinson