Compared to the technicians in the underground base, the personnel assigned to radioactive ores mining duties were much more fortunate. This was especially true when one realized how better off this group of people were compared to the rest. For one, because the mining area wasn’t attached to the underground base, it wasn’t checked multiple times for structural safety. In other words, many mines collapsed during the initial earthquake. They couldn’t withstand the level 9 quake.
However, because most of the mining operation had been automated, all the workers were above ground maintaining upkeep of the machinery when the earthquake hit. They retreated back to The Hope with a miraculous 0 percent fatality rate.