Human scientists had chosen a planet with a reasonably good geological profile; there were basically no earthquakes or volcanic eruptions, nor were there any unknown microbes detected.
But due to its location on the outskirts of the planetary system, rare earth elements might be scarce.
There was no helping it, to reduce the likelihood of being discovered by the "Bright Galaxy" human offshoot, humans could only choose such peripheral planets, and initial industrial development might be more difficult.
Fortunately, in the process of developing the Planet Engine, humans had mastered the technology to mine deep crustal resources. With some time, the difficulty posed by a lack of rare earth minerals should be largely solvable.
The first batch of engineers had already started the excavators, digging out the Underground City... they were the hardest working group, operating in an environment devoid of daylight, not even daring to light the high-intensity fusion lamps.
