Related by context. Frequent words. (Click for all words.) 49 underground 41 Zasyadko mine 40 Highly radioactive 40 Radioactive waste 39 near Carletonville 39 subterranean 38 No.2 reactor 37 Habo 37 undergound 37 tunnels dug 36 Meikle mine 36 shallow aquifer 35 Pulacayo 35 alluvial mining 34 underground workings 34 Marcellus shale formation 34 tunnels 34 magma chamber 34 Underground 34 Storage Tank 34 ventilation shafts 34 underground caverns 34 Guanajuato Mine 34 underground tunnels 33 cenotes 33 mine shaft 33 borehole 33 aboveground 33 underground aquifer 32 injection wells 32 dewater 32 penstock 32 caverns 32 undersea volcanoes 32 coalmines 32 mines 32 underground cavern 32 ventilation shaft 32 coal seams 32 La Colosa 31 sewerage pipes 31 mine shafts 31 fumaroles 31 Lake Vostok 31 manhole 31 cavern 31 tailings dams 31 geologic formations 31 crawlspaces 31 underground passageways 31 miners 31 artesian wells 30 underground passageway 30 coalmine 30 Goldstrike 30 trenchless 30 hydro fracking 30 flammable vapors 30 coal seam 30 zombie infested 30 breathable air 30 Gotthard Base Tunnel 30 coal mine 30 limestone cave 30 trapped underground 30 piping 29 trapped miners 29 induced polarization IP 29 Modder East 29 narrow passageway 29 highwall 29 cenote 29 methane gas 29 volcanic vents 29 steam vents 29 pipe 29 vertical shafts 29 underground piping 29 Homestake Mine 29 underground bunkers 29 mining 29 digging tunnels 29 aqueducts 29 trapped Chilean miners 29 ventilation ducts 29 earth crust 29 Chilean miners trapped 28 manholes 28 tailings dam 28 shafts 28 surface trenching 28 Subterranean 28 lush jungles 28 trench 28 adits 28 vertical shaft 27 passageways 27 limestone caves 27 tunneling 27 mined 27 surficial