30 CFR § 75.361
(a)(1) Except for certified persons conducting examinations required by this subpart, within 3 hours before anyone enters an area in which a preshift examination has not been made for that shift, a certified person shall examine the area for hazardous conditions and violations of the mandatory health or safety standards referenced in paragraph (a)(2) of this section, determine whether the air is traveling in its proper direction and at its normal volume, and test for methane and oxygen deficiency.
(2) Supplementalexaminations shall include examinations to identify violations of the standards listed below:
(i) § § 75.202(a) and 75.220(a)(1) — roof control;
(ii) § § 75.333(h) and 75.370(a)(1) — ventilation, methane;
(iii) § § 75.400 and 75.403 — accumulations of combustible materials and application of rock dust;
(iv) § 75.1403 — other safeguards, limited to maintenance of travelways along belt conveyors, off track haulage roadways, and track haulage, track switches, and other components for haulage;
(v) § 75.1722(a) — guarding moving machine parts; and
(vi) § 75.1731(a) — maintenance of belt conveyor components.
(b) Certification. At each working place examined, the person making the supplemental examination shall certify by initials, date, and the time, that the examination was made. In areas required to be examined outby a working section, the certified person shall certify by initials, date, and the time at enough locations to show that the entire area has been examined.