The Colonial Land Surveying thread is closed, I don't know if it got too bitchy, but I was going to post a little blurb about mineral surveys since it drifted that direction.
In the early 20th century patents begin to be issued without mineral ownership attached. It started with the Feds retaining coal rights and slipped into them owning all minerals.
Later, about mid century if I remember correctly even gravel was retained.
So now many mineral surveys are done that have nothing to do with surface ownership, except to get there the patent lines need to be considered. Here is an example of one:
This is an OG plat that helps to explain mineral ownership:
I would say Loyal is correct that most mineral surveys were also surface based since they were done on Federal lands, however, today many are done for minerals under surface ownership and have little to do with the surface owner, with the exception that patent lines need to be figured out. Because of that Scott also has a point, however, I suspect that split estate in Texas is private vs. private for the most part while out here in PLSS lands its private vs private,,,,,,,or private vs. government and often private vs private vs government.