Related by context. Frequent words. (Click for all words.) 45 monitored 42 shaft 42 shafts 40 hydraulically 38 exhaust vent 38 hydraulic jacks 37 visually inspected 37 intake valve 37 louver 36 oxygen saturation 36 odorless colorless gas 36 closely monitored 36 Elandsrand mine 36 noxious gases 36 coolant temperature 35 stopes 35 monitors 35 visually inspect 35 borehole 35 longitudinally 35 Analytical accuracy 35 hydraulic hose 35 ventilation shaft 34 miners 34 workpieces 34 properly ventilated 34 pulley 34 underground workings 34 programmable logic controller 34 valves 34 electrodes attached 34 workpiece 34 penstock 33 intervals 33 Although Nextgov does 33 mine shafts 33 near Carletonville 33 windings 33 transmitted wirelessly 33 rescuers 33 electroencephalogram EEG 33 methane concentrations 32 silica dust 32 intermittently 32 flammable vapors 32 ventilation shafts 32 hydraulic 32 submersible pump 32 underground 32 trapped miners 32 adits 32 securely fastened 32 ductwork 32 Fire extinguishers 32 flammable gases 32 carbon monoxide 32 dewater 32 Kroondal 31 Trapped miners 31 backpressure 31 retractor 31 Seepage 31 stope 31 compressed air 31 vacuum hose 31 Marikana 31 Borehole 31 ultrasonic sensors 31 magma chamber 31 Ventilation 31 continuously 31 downhole 31 sump 31 radioactivity 31 winch 31 depressurize 31 Sulfur dioxide 31 hydraulic cylinder 30 wearing breathing apparatus 30 centimeter diameter 30 acetylene torch 30 radioactive vapor 30 hydrogen sulfide 30 oral corticosteroids 30 crane 30 monitoring 30 camshaft 30 tightly 30 mineralized interval 30 methane 30 SAG mill 30 adit 30 Centrally 30 Ezulwini Mine 30 #mm diameter [001] 30 mine shaft 30 gasoline vapors 30 #ft #m [002] 30 confined spaces 30 poisonous gases 30 steel rods