Hi all!

So I'm in the mentioned quest where you have to (I think) go the second time without the dwarves. I went deep and found a place indicating me to blow up with a Grapeshot. I donno if this is the end target of the quest. I didn't have a Grapeshot so I had to go back out and get one. Now I cannot remember where that place to throw the bombs. Or isn't it something unnecessary thing to do? What's the end goal of this quest?

Thanks for any input!

With Flickering Heart sends you to the catacombs, not the Vergen mines. You're thinking of 'Hey, work's on in the mines' where you have to destroy rotfiend tunnels.

***** SPOILER *****

See here...
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http://www.gamebanshee.com/thewitcher2/walkthrough/heyworksonintheminesiorveth.php

No, I have finished the Mines quest. I'm doing the Flickering Heart. So, you don't go to the mines. Ok, I'll see where are the catacombs

Ok, then make sure you go to Felicia Cori (the femaile trader at the entrance to Vergen) and buy the surgical tools. This is very important if you want to collect evidence while in the catacombs.