[Experimental] Mineshaft generated in the air without any support

Summary:

Mineshaft generated in the air without any support.

The problem seems to be a great distance from the ceiling and floor of the cave. There are chains near the stone passage.

Seed: -1927884317
Coordinates: -106 5 -735

Steps to reproduce:

1. Create a world with the specified seed.
2. Move to the specified coordinates.
3. Explore the generation of mineshaft.

Observed results:

Mineshaft hovers in the air (without any support).

Expected results:

Mineshaft will be with chains or columns.

Image: