Penumbra is real - possible inspirations?

[The Rock Worm]

Recently heard about this http://en.wikipedia.org/wiki/Qaqortuatsiaq To quote from the page
Qaqortuatsiaq is a former settlement on the northern shore of Appat Island in the Qaasuitsup municipality in northwestern Greenland. Its ruins lay against the Torsukattak Strait of Uummannaq Fjord.
Qaqortuatsiaq was a marble quarry[/url] and, though presently abandoned, seems likely to be revived in the future.[url=http://en.wikipedia.org/wiki/Qaqortuatsiaq#cite_note-noclose-3]
This just screams Penumbra to me. I wonder what monsters people would find if they drilled deeper into the abandoned (at least by humans) mine?