Same here, dude, and I have a feeling we're not going to get an answer anytime soon. Even confirming that someone on the outside is pulling the strings would give us way too much information about the world we're working with here.

[Newt will join Hiro at the volcano's edge and PUSH HIM IN HAH HE WAS THE MAFIA THIS WHOLE TIME jk but he sure is checking out that lava down in there. Neat!]

The Breach isn't so much a physical construction as it is, like, a bridge between two dimensions. I don't think a volcano would melt it down. That said, a volcano definitely would melt down some robots, so... Yeah, looks like we struck out. Bummer.