Of course you couldn’t dig a shaft without raking up the rock and dirt you were displacing. This material—"spoil"—had been distributed around the complex and used to buttress, or to completely bury, outlying facilities such as tanks, processing plants, and buildings that seemed to have a lot of expensive people in them ("command and control" in T.R.-speak). Without being terribly obvious about it, the designers had, in other words, hardened the site. Rufus, at a glance, had identified some of the spoil-piles as "revetments," obliging Saskia to look up the word. It meant a sort of blast wall built around a potential target to protect from near misses by artillery. It didn’t take a military expert to know that a cruise missile could obliterate anything on the surface. But it seemed proof against small, furtive attacks such as bomb-bearing drones or mountaintop snipers. Large areas were screened by nets with strips of fabric woven through them. Their purpose wasn’t entirely clear to her, but they would definitely stop drones, provide much needed shade, and make things complicated for surveillance satellites.