About a 50hp tractor with a Beltec carbide tipped auger. You need the down pressure on the hydraulics to push through the rock.

Oh man, I just noticed you are in Wise County. I know just what you are getting yourself into. The Beltec carbide tipped auger is the only style that will do it. It will raise the rear wheels to place weight on the auger guide because the auger will try to skate when it hits that hard limestone. Then it uses hydraulic pressure to push down on the auger. It’ll drill through anything short of rebar reinforced concrete, and it will put the hole right where you want.

That’s how I’ve seen it done.

Dave’s way will also work if the front on the skidsteer is heavy enough to hold the auger in place.

Oh, don’t expect it to go quickly. It took my neighbor three days to drill holes for his backyard fence. He drilled dry though, I would water the hard bottom holes.

Any of you know if a BelTec will go through granite ? We have plenty of both granite and limestone up here. Sometimes fence posts get a pile of rocks for a base.