Hey, you there! You got 12,000,000 dwarfbucks? Okay, I'll show you what I'm offering. Here in my hand is a book. Inside is the teachings of Gravity. Now, this seems useless on the horrors of the deep. Why, in the depths of the Earth, where would you find cliffs other than the chasm?
But lo, there is a secrect within this book. While I have yet to see the miracle blue gold myself, the cursed toumb of nightmares, I have seen the writings of those blessed by the gods to survive. While the depths do have a number if limitations when it comes to weapons of immsense power, there is one thing that we use every day, something that can cause the death of even Ironblood.
When you uncover the pits of despair, wall them off and dig out their surroundings. You WILL need the ground overhanging the chambers. Create a great earthen pillar, one resembling the hammer of Armok! You will collapse it onto the chamber, crushing the nightmares beneath the majesty of Dwarven egnineering!
Of course, I have never seen this attempted. It is a word of warning to whoever is crazy enough to open those cursed groves of chaos in greed. While this is a possibility, it would require the best Dwarven minds to construct such a holy structure of clensing.
Now included in this tome are plans for the entire fortress. Should the primary plan fail, a lever guarded in a closed vault hidden beneath the tombs of the dead heroes of battles past will cause the whole fortress to collapse into the pits. This will seal them again, saving the world from the horrors of the deep.