I've beaten the boss and cleared out the area, but when I click on the cart to set off the explosives - all I get is a statement that says "It isn't safe to unload the powder right now." I don't know what else to do at this point. I've finished all the other quests for this area.

Got the same bug. You will have to load a save before you enter the eastern or western part of the cave. That at least worked for me.

Dang. I was afraid that would be the answer. That will require a lot of rework, but I don't have much choice if it won't go. Thanks.

Did it worked? If you load again from autosaves from the start again you said that the glitch will pass?

Don't know if it has to be a autosave. On my first playthrough I used all available save slots. I just loaded a save before I entered the western part of the mine and it worked.

I also have this issue, unfortunately I have no older save, is there any plan to fix this issue?

There are supposed to be two barrels of explosives already set in strategic locations. One is near the end of the tunnel. The other is closer, opposite the flaming trench. If either one of these barrels is destroyed, either accidentally or intentionally the aforementioned message is displayed... erroneously and very misleading.

 

Is there a way to replace one of these barrels other than reloading? I don't know but I doubt it.

I also have this problem - I have probably done everything possible wrong that have already been raised - a number of mid-fight saves; destroyed the barrels etc etc. Is there any plan to fix this in a future patch? If so I will leave this game for a while and go play Skyrim/Two Worlds II/Witcher II and come back to it in a couple of months?

Sadly, I raised this bug in detail 4-5+ months ago with this exact error. It hasn't been fixed, and I have been trying the updates via steam in the vain hope it has been corrected. Well, it hasn't and continues to block my game, I haven't played in since and will not buy another Obsidian title ever again, regardless. In my opinion a bug this game breaking cannot go unfixed for any prolonged period, ever. DS3 was a far cry from 1 or 2, but due to the recent (back then) Obsidian titles that were pretty damn good, I decided to ignore the bad press and get it.....was quite enjoyable until this bug. So, uninstalled and the CD is now hanging in my veg plot as a 'scarecrow'. But hey, what do Obsidian care, they're developing new titles for the multi format gravy train which is killing PC gaming.

 

Sorry for the rant, but I cannot bear slack post sales support or multi platform titles for that matter, either.