On a different not, besides the brewing of their fine ales, I was idly trying to come up with some questions I had about Dwarves (for no particular reason and with no outward motivation or ulterior motivation) and the one that tickled my fancy was about their caves.
Many meandering thoughts so will will sort of stream of consciousnesses them.
The creation of dwarves. Do you think their stature and strengths drove them to the caves or became from them? Nature vs. nurture I suppose. Regardless of the reason they were pushed or stayed in the caves, I think of them gollum wise. And if they aren't a distinct species that developed there per a god or what have you, then who did they evolve from and how would that bend a fantasy campaign? Dwarves were once elves 150,000 years ago!? AAAHHH
So then the caves themselves. If I was mining a mountain for precious metals and came across a mighty cavern of intense beauty, I am not sure I would care. I would probably use the natural portions of it to continue my dig in the most economical way I could. I would divert the water to run some machinery, use the stalagmites and such as stools and or stepping stone and basically scoop out the innards in a way to make it easier for me to keep digging. I was just thinking about making a cave type sub and decided not to but still had these thoughts. So a cavern made by dwarves, at first I sort of thought of it as a borg-like structure. Very utilitarian and economical. Of course they might have more ornate things going on, but the bulk of heavy moving of rock would be pretty darn efficient and logical, so I thought.
Continuing along those thoughts, I remembered what I do in minecraft. I clean very large sections of room but only as high as I can reach. No sense going too high unless there is a reason. If I feel I may have missed something above, I will create a stairs and cycle upwards and clear the next level leaving a block or two inbetween the levels. Effectively creating stories of excavating. More often than not though, I will hit a vein which will detour me, however I need to go, to get it all. Then, since I am there, I start clearing another larger room till I find something else.
So even efficient and utilitarian digging is going to create an insane amount of unorganized twisting, turning, rising and falling of tunnels which follow the veins. These will be sporadically interrupted by huge halls where the veins were lost and random mining is searching for the next possible metal cache. While it may not make sense to a human explorer and the patterns appear random and half-hazard, there is perfectly logical explanations for the most convoluted series of tunnels.
Just random thoughts...