1. When a hero captures a Fortress or Castle, all mines change to their color, but this doesn't mean they provide you with everything they should. Until you visit them, a wood and ore mine will only produce 1 unit each, a crystal mine will produce 0, and a gold mine will produce 250 per day.
I recently played a skirmish, and I specifically didn't visit these mines as you suggest. I bought tons of troops throughout the war, rebuilt dozens of cities, and exchanged hundreds of wood and ore for gold. Still, at the end of the skirmish, I had hundreds of wood, ore, and crystals, and 200,000 gold. And I didn't play for very long. So, your information needs to be confirmed by several other forum members. IMHO
