system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] Just how deep did the Dwarves dig in Moria?

Rewatching The Two Towers right now, and watching Gandalfs fall while battling the Balrog popped the question into my head. Now I realize that is certainly a natural chasm, but the Dwarves were living there for a very long time before awaking the Balrog. 

Watching the fall made me realize that I'm bad at math and physics, trying to do that calculation and guesstimate the height and speed and such from that one scene. So hoping someone else is able to do that better also as a secondary question.
gpt
>'Deep is the abyss that is spanned by Durin's Bridge, and none has measured it,' said Gimli.

Even the dwarves don't know about the extent of the natural tunnels they pierced when they set free Durin's Bane, and they don't talk about the deepest levels where they dug for mithril, only that it was found "at the root of the mountain".