My neighbor hood is in a classic karst region. There are many sinkholes varying from medium to large. Development resulted in covering the bottoms of several. The result is always runoff filling and sometimes flooding. The dirt fill usually clay has to be removed before proper drainage is restored. The drainage is underground to the river half mile away.
Another way they can find tombs, mineral deposits, other subsurface things, is remote sensing (spectral, 5 or 7 bands) of vegetation. The false colors can be adjusted so that vegetation with slightly more copper, for instance, content looks different in the display and mineralized ground is right there, just go and run some core samples to ground truth it.