With some careful poking and math... Yeah, more or less. 

All right. That's small enough for Solas to reach the far side with a barrier and prevent any retreat or reinforcements.

Cassandra will screen, then Solas, then the soldiers, then Varric and Lionheart.

Works for her, at least. 

And as no one else has a problem with it- They proceed.

The plan goes off without a hitch, Cassandra taking the initial attacks on her magically-imbued shield, Solas sealing the exit. And then it's just a matter of pushing front to back.

This time, she at least tries to get her hands on the remains of a wisp, even if she can't get a live one.

She can find a little cloth-like scrap on the floor where one faded out.

...Hm.

"Do demons normally not leave corpses?"

"Not unless they are possessing someone, no."

"...Weird."

"I'll need to get my hands on one to best use Amestrian alchemy against them, though."

"Containing a demon is difficult at the best of times."

     "Blood magic would do it," Varric says, then throws his hands up hastily to ward off Cassandra's glare. "Not that I'm suggesting anything, Seeker. But you know Kirkwall was full of fucked up shit towards the end there. I've seen it."

"What's blood magic?"

"When a mage would rather have instant power than any sort of moral center, they can steal the energy in someone's blood to power their spells."

     "Sometimes themselves, mostly it's other people," says Varric. "Usually winds up killing the poor idiot."

" - What does 'killing the poor idiot' usually look like?" she asks, totally failing to hide how she's now Very Suspicious of what blood magic might involve.

"Exsanguination. Messy."

"So they just bleed out? Nothing goes - missing?"

"Uh. Not that I could ever tell. What are you thinking, Shorty?"

" - There's a branch of Amestrian alchemy that sounded similar at first brush, human transmutation. It's pretty much illegal the same way suicide is, though, and it - has pretty notable side effects."

"Based on that name... yeah. Doesn't sound like fun." He shakes his head.

"Yeah. The domain of the foolish and the desperate."

"Then it is best avoided."

"I'll be keeping away from it."

Nod.

Then they continue on through the mine. There are a few more packs of demons, but no rift. No sign of Leliana's scouts, either.

Concerning... But they'll move as quickly as is safe. 

Which is reasonably fast, all things considered.

Once they make it through and out to the surface on the upper side, they can spot a small group huddled defensively with their backs to a steep drop-off being harried by a rift spawning demons.

She claps - kneels - 

And pulls a rifle from the ground. They're at a large range, still, with a lot of rough ground between them and the demons - so, long range weapons it is. 

She stays kneeling while she quickly sets up the sniper rifle and then starts taking pot shots at demons farther from the allied group. 

She's no Hawkeye, but Bellona's still a pretty good shot.