Scenario:

• Player is using Babylon (side B)
• 2nd wonder has been completed (allows playing last card of each age instead of discarding)
• Player has a Mine in play (can produce either Stone or Ore)
• Player has no other way to produce Stone or Ore and no money to purchase from a neighbor
• It is the 6th turn of Age I
• Player has a Barracks and a Baths in hand (resource cost of one Ore and one Stone, respectively)

Can the player play both Barracks and Baths?

The 2nd wonder allows the player to play both the Barracks and Baths (assuming he can pay the costs), instead of having to discard one. The Mine can produce both resources, but the rules regarding cards that can produce more than one type of resource state:

the player can use one OR the other resource to build a structure (or a wonder phase) but NOT both in a given turn.

Both cards would be played in the 6th turn, so it would seem that the player cannot use the Mine to pay the cost of each card. However, is the limitation on using resource cards only once per turn really meant to be once per construction? (Which is how we ruled it during a game.)

This question really applies to any resource producing card, not just the multi-resource producing cards. It was just simpler to explain this way, and the issue is more fuzzy due to the specific prohibition on multi-resouce producing cards being used more than once in a turn.