30 CFR § 57.4660
Work in shafts, raises, or winzes and other activities involving hazard areas.
During performance of an activity underground described in Table C-2 or when
falling sparks or hot metal from work performed in a shaft, raise, or winze
could pose a fire hazard--
(a) A multipurpose dry-chemical fire extinguisher shall be at the
worksite to supplement the fire extinguishing equipment required by
§57.4600; and
(b) At least one of the following actions shall be taken:
(1) Wet down the area before and after the operation,
taking precaution against any hazard of electrical shock.
(2) Isolate any combustible material with noncombustible
material.
(3) Shield the activity so that hot metal and sparks
cannot cause a fire.
(4) Provide a second person to watch for and extinguish
any fire.
Table C-2
+---------------------+-----------------+-------------------------+
| Activity | Distance | Fire hazard |
+---------------------+-----------------+-------------------------+
| Welding or | | More than 1 gallon of |
| cutting with | | combustible liquid, |
| an electric arc | | unless in a closed, |
| or open flame | | metal container. |
| Using an open flame | Within 35 feet | More than 50 pounds of |
| to bend or heat | of-- | non-fire-retardant |
| materials | | wood. |
| Thawing pipes | | More than 10 pounds of |
| electrically, | | combustible plastics. |
| except with | | |
| heat tape | | |
+---------------------+-----------------+ |
| Soldering or | Within 10 feet | Materials in a shaft, |
| thawing with | of-- | raise, or winze that |
| an open | | could be ignited by |
| flame | | hot metal or sparks. |
+---------------------+-----------------+-------------------------+
(5) Cover or bulkhead the opening immediately below and
adjacent to the activity with noncombustible material to prevent sparks or
hot metal from falling down the shaft, raise, or winze. This alternative
applies only to activities involving a shaft, raise, or winze.
(c) The affected area shall be inspected during the first hour after
the operation is completed. Additional inspections shall be made or other
fire prevention measures shall be taken if a fire hazard continues to
exist.