30 CFR § 57.22605 Blasting from the surface (V-A mines).
(a) All development and production blasting shall be initiated from
the surface after all persons are out of the mine. Persons shall not enter
the mine until ventilating air has passed over the blast area and through at
least one atmospheric monitoring sensor.
(b) If the monitoring system indicates that methane in the mine is
less than 1.0 percent, persons may enter the mine, and all places blasted
shall be tested for methane by a competent person before work is started.
(c) If the monitoring system indicates the presence of 1.0 percent or
more methane, persons other than examiners shall not enter the mine until the
mine has been examined by a competent person and the methane level is less
than 1.0 percent.
(d) Vehicles used for transportation when examining the mine shall be
approved by MSHA under the applicable requirements of 30 CFR parts
18 through 36.
(e) This standard applies only to mines blasting within an oil