I build my base over ore surface marker so I know there will be ore beneath the base. Base is 2 story, 15x15 and put 4 columns to support roof. I mine beneath the base, clearing all stuff up to the where base walls meets the ground. I continue the columns, making identical ‘rooms’ same size as the main floor of the base. I make 3 such rooms beneath each other. First sub-base room is where all the generators go. Second sub-floor is where I put a water pool for water supply. Third sub-base room is where I put all the workstations and forges that I eventually moved from the first floor of the base. All walls of the mine are smooth, eventually reinforced concrete. Same for ramps dug to bedrock started from the middle of each wall of bottom-most sub-base rooms so the ramps are straight and one each north, south, east and west. So, yes I’m ocd to the max lol.