Couldn't find any info on this here, so I guess I must have missed some crucial info in the manual, but here goes. How do you prevent units from clearing your own mines?
Don't walk into your own mine fields with regular infantry and don't point your engineer units at your own minefields. Just remember that regular troops have to be in the minefield to clear them and engineers can work from the adjacent hex but ONLY if they are facing towards the mines.
So..... you may ask "how do I set up my engineer units to defend directly behind my own minefield" and the answer is you don't. Leave at least one hex between your defending engineers and your own minefields
Don
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If you find you are constantly reacting to your enemy's tactics instead forcing the enemy to react to yours, you are losing the battle..