The Boring Company Achieves "Holy Grail" Zero-People-in-Tunnel Continuous Mining

I wonder how this would work in hard rock mining? Hard rock, AKA 'competent rock' is often encountered in mineral extraction. A deposit is often deep in the ground - so an 'open pit', AKA 'open cast' mine would need a huge pit - 500-1000 or more to be opened to reach the ore. Currently this is done by drill/blast methods to create a ramp large enough for a mine truck(battery powered) is driven to the face of the deposit where the ore is drilled and blasted into moveable fragments (AKA 'muck') which is then moved to the surface by these trucks. The ones shown here state they are small in size - what is the largest? Can it work in competent rock - granites etc? Can 4 - 36 inch small tunnels be driven within a ~~ a foot of each other and then caved to a squarish cross section that can be squared? It is an interesting idea. The Las Vegas underground rock is very fragile compared to the competent rock encountered in mineral exploration at depth = might not work well in the hard rock. These deep rocks are often well below the water table = high pressure water that is must operate within or pump out = hard if fractured?