I love the idea of wireless so much and always have, I just don't trust it for stability.  Sometimes it works great, other times not so much.  I have a wifi security camera system that was horrible before I got a decent wifi router.  Now it's pretty much never offline.  In that case, it wasn't very practical for me to run ethernet to every single camera in and outside of my house.

In the case of running ethernet to one location where it currently doesn't exist, I'd just take the time to do it.  Make one cable run to a switch in your mining room.  Depending on the location of the router and the location of your mining room, it may not be super easy, but I'm happy that I made the choice to do it.