There is a hypothesis in this question:

There are 4 Trasure chche in copper tresure card in basic game.

If all of the equipments are with heros, in other words, only tresure cache cards in pool. And then at the same time, heros open a copper chest in dungeon.

So all of the tresure cache cards can be drawed.

Question:

Whether All of the tresure cache cards are effective to heros (like gain coins or potion etc.) or there is auything else to limit tresure cache cards be drawed ?

yakumoran said:

There is no limit to the number of caches drawn in a row, if you get them that way (that I know of anyway.) In the case you describe, the heroes would draw out all the caches at once assuming they roll at least one treasure draw.