From the Introduction:
Dwarves are known for the grand halls they construct in their underground holds. This one can be seen as a good example to prove the point. The hall has two entrances. One in front of the throne sitting on a raised platform at the hall's center and one equally far away behind it. One entrance for the king under the mountain and his entourage and the other for the common folk.
The ceiling of the grand hall stretches across the width and length of the room far above, supported by enormous pillars. In between these pillars long tapestries and brass braziers are hung. The former to dived the vastness of the room and the latter to provide more light. Another source of light are the channels in floor where molten metal quickly flows along from the furnaces beyond one side of the hall to the molds beyond the other side of the hall.
This stream of molten metal not only lights and heats the hall it serves to show of the hold's wealth as well. The walls shaped to look like well hewn and set stones serve a similar purpose, as this is only ornamentation and the hall is actually hewn from the mountain. In addition the hall is large enough to allow all dwarves of the hold who are of any importance to gather at once.