Ventilation | Midpage57.22201Mechanical ventilation (I-A, I-B, I-C, II-A, II-B, III, IV, V-A, and V-B mines).57.22202Main fans (I-A, I-B, I-C, II-A, III, V-A, and V-B mines).57.22203Main fan operation (I-C mines).57.22204Main fan operation and inspection (I-A, II-A, III, and V-A mines).57.22205Doors on main fans (I-A, II-A, III, and V-A mines).57.22206Main ventilation failure (I-A, II-A, III, and V-A mines).57.22207Booster fans (I-A, II-A, III, and V-A mines).57.22208Auxiliary fans (I-A, II-A, III, and V-A mines).57.22209Auxiliary fans (I-C mines).57.22210In-line filters (I-C mines).57.22211Air flow (I-A mines).57.22212Air flow (I-C, II-A, and V-A mines).57.22213Air flow (III mines).57.22214Changes in ventilation (I-A, II-A, III, and V-A mines).57.22215Separation of intake and return air (I-A, II-A, III, and V-A mines).57.22216Separation of intake and return air (I-C mines).57.22217Seals and stoppings (I-A, I-B, and I-C mines).57.22218Seals and stoppings (III, V-A, and V-B mines).57.22219Seals and stoppings (II-A mines).57.22220Air passing unsealed areas (I-A, II-A, III, and V-A mines).57.22221Overcast and undercast construction (I-A, II-A, III, and V-A mines).57.22222Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines).57.22223Crosscuts before abandonment (III mines).57.22224Auxiliary equipment stations (I-A and III mines).57.22225Auxiliary equipment stations (I-C mines).57.22226Testing for methane (IV mines).57.22227Approved testing devices (I-A, I-B, I-C, II-A, II-B, III, IV, V-A, and V-B mines).57.22228Preshift examination (I-A, I-C, II-A, III, and V-A mines).57.22229Weekly testing (I-A, III, and V-A mines).57.22230Weekly testing (II-A mines).57.22231Actions at 0.25 percent methane (I-B, II-B, V-B, and VI mines).57.22232Actions at 0.5 percent methane (I-B, II-A, II-B, IV, V-B, and VI mines).57.22233Actions at 0.5 percent methane (I-C mines).57.22234Actions at 1.0 percent methane (I-A, I-B, III, V-A, and V-B mines).57.22235Actions at 1.0 percent methane (I-C, II-A, II-B, and IV mines).57.22236Actions at 1.0 percent methane (VI mines).57.22237Actions at 2.0 to 2.5 percent methane in bleeder systems (I-A and III mines).57.22238Actions at 2.0 percent methane (I-B, II-B, V-B, and VI mines).57.22239Actions at 2.0 percent methane (IV mines).57.22240Actions at 2.0 percent methane (V-A mines).57.22241Advance face boreholes (I-C mines).