Related by context. Frequent words. (Click for all words.) 41 ventilation 40 MSHA 38 coal mine 38 coal slurry 38 coal seam 38 ventilation shaft 37 Mine Safety 37 Kemerovo region 36 mineshaft 36 stope 35 Sago mine 35 Aracoma 35 J. Davitt McAteer 35 Coal Mine Safety 34 coal seams 34 Sago Mine 34 water 33 air 33 mine shaft 33 ductwork 33 air intakes 33 exhaust gases 33 coal mines 33 drainage 33 Crandall Canyon mine 33 ADEQ 33 water heater 33 coalmine 32 vents 32 blowout preventers 32 ventilate 32 breathable air 32 Crandall Canyon 32 ERCB 32 Clean Water Act 32 valley fills 32 Sergei Shoigu 31 toilets 31 ventilated 31 respirators 31 Montcoal W.Va. 31 Peter Whittall 31 DEQ 31 Kevin Stricklin 31 furnace 30 COGCC 30 OEPA 30 duct 30 flues 30 coolant 30 mine shafts 30 toxic gases 30 coal ash 30 firebox 30 ventilators 30 carbon monoxide fumes 30 boiler 30 electrical wiring 30 dryer vent 30 W.Va. mine 30 flue 30 ducts 30 vertical shaft 30 breathing apparatus 30 air ducts 30 passageways 30 DRBC 30 TCEQ 29 BOEMRE 29 Crandall Canyon Mine 29 furnaces 29 PHMSA 29 Randy Babbitt 29 exhaust pipe 29 trapped miners 29 longwall mining 29 Ventilation 29 Oppegard 29 portable heaters 29 gases 29 TDEC 29 Michael Bromwich 29 Massey Energy 29 longwall 29 automatic sprinkler 29 Sago Mine disaster 29 airway 28 nozzles 28 ducting 28 Li Yizhong 28 Barofsky 28 valve 28 recirculation 28 boilers 28 crawl spaces 28 Nuclear Regulatory Commission 28 compressed air 28 heat exchanger 28 evaporator 28 Thrift Supervision 28 stairwells