Once mature, a player must roll on the Mine Assay Table to determine the level of output the mine will yield each quarter. It is possible that it will be a bust and be worthless. I speak from experience. Other cards which can surface, as mentioned earlier, are troop cards, bandidos, indians and political offices. These cards are also bid upon and players can then use the soldier cards to perform various actions - taxing, raiding, burning, pillaging and the like.
Political offices can also prove quite powerful, as explained later.
And, of course, let's not forget the dreaded Event cards. Even Haley's Comet can make an appearance and cause troops to flee in panic. However, it is this vast variety that is the game's greatest obstacle. Unfortunately, the rules do not cover every possible event or direction that the game can take. He was more than kind to answer these, but even he admitted several times that the rules did not fully address some of the situations we encountered.