Damage from minefields.

[Dog Soldier]

FWIW,
Minefields by themselves cause little casualties. Their main function is to channel an attacker to avoid them. They do cause significant movement delays.

Minefields have some indirect and more subtle advantages for the defender.

Because minefields are passive, defending players should cover minefields with adjacent units, preferably in covered hexes and at least in IP or TRENCHES if possible.
Have another unit or more close by if possible.

Units in minefield, IIRC defend against an assault at 1/2 strength. Disrupt an attacker in your minefield and they defend against an assault at 1/4 strength, like a broken unit. I know this is stated in the manual for engineers attempting to clear a minefield. It has been a while, but I think it any other units in minefields suffer a defensive penalty or a reduced assault value to hurt your units.

Now assault that unlucky enemy unit with whatever force you can. Be sure to move another friendly unit into the hex you assault from to maintain the fortification (IP, TRENCH etc) if one exists. Watch your stacking limit so your assaulting unit(s) can return to their original positions.
Units which start adjacent to the minefield can assault and return to their original positions after a successful assault. Calculate the movement costs of any units which have to move up to join the assault carefully.
The risk is that the assault will fail and leave your defenders disrupted in the enemy turn. Since there are no guarantees, weigh the costs versus the benefit of the assault in the current tactical and strategic terms.
There will be times when such attacks can pay off handsomely.

Such assaults can cause anywhere up to 40% of the unit in the minefield depending on its condition at the time of assault. Even a good order unit in a minefield can be damaged significantly. In many cases the unit in the minefield will be disrupted and forced to retreat. If it cannot due to stacks behind it, well.... it can really be punished. Such opportunities are to die for...I mean for your opponent to die for.

Now this technique will not always yield great results. It works best if the defender plans ahead for it. Artillery or an unlucky die roll for the unit entering the minefield causing disruption of the unit in the minefield sure make advance planning pay off for the defender. At the very least, the defender will upset the attacker's time table a bit. And every bit of time bought when defending helps. Another benefit is this counter attack on attacking units disrespecting your defending minefields may make the attacker more cautious and slow his advance.

Dog Soldier