Greyspine Quarry

Greyspine Quarry, also known as the Keystone Quarry, is the dwarven mithral mine located in Kraghammer. In Season 1 of Critical Role, the mines are the central location where K'Varn sends his minions through in order to test the defenses of Kraghammer.

Mine Description
Greyspine Quarry is owned by House Greyspine. The mine itself is made up of three deep holes that stretch far into the side of the mountain going down. As the mine is dug out, Kraghammer slowly begins to build up in areas that are no longer in use, thus allowing the city to expand downwards. Many mining buildings stretch around the center of the quarry. There are also a series of tunnels that go off to the sides of these main tunnels, often times dwarves will come across a goblin den that needs to be cleared out.

Background
Prior to Lady Kima and Vox Machina's arrival, the mine had been fairly prosperous, though labor intensive as the owner of the mine, Nostoc Greyspine, tends to work his employees to the bone. However, at some point abominations began to come through the mine into the lower levels of Kraghammer. Eventually, these creatures caused the miners to close off several tunnels in order to protect Kraghammer. During this time many workers were caught either by these monstrosities or by Duergar and taken into the Underdark presumably to be used as lab rats or for sport by the Duergar.

Attack at The Quarry
Through Nostoc, Vox Mochina discovered Lady Kima with a group of mercenaries traveled into the Underdark through the quarry. While the party was in discussion with Nostoc, an alarm sounded as several goblins and a couple of ogres came through the quarry tunnels, killing several dwarves along the way. While fighting with the band of creatures, the group realized that the creatures were actually running from something. Eventually, a mutated Naga with five additional Naga heads broke through a stone wall Keyleth erected to slow it down. During the ensuing fight, Scanlan made his very first kill by shooting a bolt of lightning into the creature. Vox Machina then contracted with Nostoc to find and kill the source of these monster attacks while the foreman of the mine, Herris, provided Vox Machina much of their information on the mine.

Afterwards, the group prepared and went into the quarry where they discovered a mine entrance that fed into some underground caverns where everything had been coming from.

Aftermath
The party was able to recover Lady Kima and defeat K'Varn, however, Vax voiced concern that the Duergar or Illithid might want revenge and come up through the Greyspine Quarry mines after the events in the Underdark.