Just need to make sure to calculate the exhaust fan m3 air sucking capability and the hole for it, start with a small hole, if the intake air is only coming from the hole then is good, if the intake air is coming from the hole and other places then it means the hole needs to be bigger or make small holes only, need to watch out for thieves, holes larger than 20x20 is dangerous but if your place is very safe then I'd say larger holes are better. A rule is, if you have a 50x50 exhaust fan then make a 50x50 hole but like I said before, it will depend on your exhaust fan sucking capability.
I have a couple different options for mining locations, but right now a hole large than 20x20 would be extremely dangerous in my opinion. I don't want anybody (or anything) crawling through it to get to me or my stuff. The hole should match the size of the exhaust fan, is that right, generally? I know the sucking capability calculations are going to be more accurate, but just for estimation-sake.
I think I've got everything I need and expected from this thread. Very helpful discussion, and I've got a pretty clear picture about how to proceed efficiently, without damaging my hardware in any way. Metroid is the MVP here, sorry that I don't have any merit to dish out to ya. I'll probably be locking this bad boy, unless I think of another question or run into another related issue. Appreciate the help.