You are correct self replicating mining machines revolutionise mining.

Where are they today in mining?

I would suggest you study the work of Diane Newman at Caltech. She bred bacteria that breathe rock and **** valuable metals like gold and copper. They're working in copper mine tailings today and are revolutionising mining industry.

Others are looking at extending this capability to control weather.

http://www.niac.usra.edu/files/studi...Manobianco.pdf

I've made some small contribution to the art and have even commented on it here decades ago. Of course all I've gotten for my efforts is mindless abuse. Which makes your venue here so popular. Not! LOL.