Built this myself in 7 days. Took 54 hours. Not proud of how no life i went on building this, but its a cool build. You can find it at x:513 z:-4156. In the nether the closest portal is at x:58 z:-508 theres a cobble stone slab path to it. You'll need to max your render distance to see it from the viewing platform
I don't ever play vanilla, but doesn't a vanilla cobblegen involve standing there staring at it and actually mining?
you dupe tnt to blow it up, pistons push it into a blast zone, all automatic. Mojang wont patch tnt duping because of how relied upon it is in the redstone community until they replace it with something better in the future