Two different experiences with Infested Mines

I have a problem that I'm trying to solve but I've also found something interesting with the infested mines. I'm curious if anyone has done any research into this. I play on two different worlds, separate characters, so no interaction between these worlds. Both worlds started during mistlands beta.

World A I have cleared 4 infested mines.

13 Black Cores

3 Sealbreaker fragments

0 Boss stones

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World B I have also cleared 4 infested mines

4 Black Cores

11 Sealbreaker fragments

1 Boss stones

World A, the mines have been pretty small with lots of secret rooms, probably 3 or 4 in each dungeon. World B, the mines are pretty sprawling with some rooms quite vast, only 1 hidden room in 4 dungeons. I often have to leave and come back for rested bonus, just to give you an idea of how large these are. I know 4 dungeons is not a large sample size, but I'm trying to figure out why they are so different. Is this something that can be taken advantage of based on what you need at the time. The first world is preferable because you need black cores before sealbreaker fragments. I am assuming those are to summon the boss.

I'm curious if proximity to the boss location affects what spawns in the dungeons. Or maybe dungeons to the south are a certain type and dungeons to the east and west are a different type. Or maybe you can tell what type of dungeon it will be from the entrance structure? I think I've seen 3 different types, a dverger building, a stairway coming up from the water practically, and a quarry looking place. Thoughts?