Quote from Bombenbodo2 on 2011/02/14, 11:42

Creating mine cards with activated diamond blocks works like a charm. Additionally I would suggest that a destroyed mine cart does not drop back to the player - people already started flooding the market with mine carts ...

PS: I would really appreciate if you could remove the bedrock at water level from lot l21 which was used to remove the text visible to the map - I thought I read the rules but didn't hit that one - sorry :/