Missing a Breaching barrel for the Black Powder Mine

[Karl Franz]

I've searched the maps and all the breaching locations at least thrice and I cannot find the last barrel I need for the Black powder mine which contains the Raw ruby.
There are not enough resources to upgrade the weapons and I'd like to finish upgrading the hammer to 100% the game.
Can someone point out all the locations of the breaching barrels which you have found?

[Astronimo]

In the second location, do quest for Luca. You will eventually end up on map with one extra barrel.

But in general it seems like you have missed it. For reference, there is a barrel over that chest. It's hidden

[Karl Franz]

Thank you for the info although I did the quest already and I think it is not possible to go back? I will check!

[Narcissistic Cannibal]

https://youtu.be/WoaOVYd95G8
Barrel at 1:00

[Karl Franz]

Damn, this was my mistake. I took this barrel but did not open the breach XD
I am screwed. I will never know which barrel I missed.

[Astronimo]

There are limited amount of barrels. Each breach has an icon on the map. Just lurk around you have already opened