Ore
Treasure - Reserve - $4
When you play this, put this on your Tavern mat.
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At the start of your buy phase, you may call this, for +$2.
This card is no Kingdom card. There are 24 Ores in the game.
So it's a new base Treasure, a la Potion. Unfortunately, there's really no indication when they're supposed to be used, and most of the cards in this expansion are severely underpowered/completely useless in the absence of Ores, so I suggest adding a new card type, such as "oredigger," that simply adds ore to the supply when present, similar to Looters and Ruins. Other than that, I like it. (We could also just be supposed to use it when any kingdom cards from Progression are used.)
Prospector
Action - $4*
+1 Action
Choose one:
+$1 +1 Action;
or +2 Cards and put 1 card from your hand on top of your deck.
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During your buy phase, this card costs $1 less for each Ore on your Tavern mat, but never less than $0.
I think that the first option will be chosen very rarely (Lab variant or Squire?), but other than that, it's good.
Demolition
Action - $3 $2
Trash this and another card from your hand. If you do: Gain 1 Ore and put in on your Tavern mat.
I don't really have anything to say about this one.
Melting Shop
Action - $3
+1 Buy
You may call any number of Ore from your Tavern mat for +$3 each.
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During this turn, when you call an Ore from your Tavern mat, you first get +$1.
That horizontal line isn't really needed.
Digger Camp
Action - $4
+2 Actions
Reveal the top 2 cards of your deck. Put the revealed Treasure cards into your hand. Put the other cards back on top in any order.
Interesting. Possibly too weak, though (Treasures are generally the rarest cards in people's decks, assuming all playgroups are like mine).
Double-card pile (5 Monks and 5 Sanctuaries)
Monk
Action - $4
+$2
+1 Action
You may trash a Treasure card from your hand.
Sanctuary
Action/Victory/Reaction - $4
+1 Card
+1 Action
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2 VP
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When one of your Treasure cards is trashed, you may reveal this. If you do, you may put that Treasure card on your Tavern mat or the top of your deck instead.
All sorted piles are sorted in order of increasing cost, but these two cards cost the same. How are we supposed to know which card to put on top? I suggest increasing the cost of Sanctuary to $5. It's probably strong enough to justify that cost, anyway. Also, it doesn't say where you may reveal it from. It should say "you may reveal this from your hand," not "you may reveal this."