30 CFR § 77.1304 Blasting agents; special provisions.
(a) Sensitized ammonium nitrate blasting agents, and the components
thereof prior to mixing, shall be mixed and stored in accordance with the
recommendations in Bureau of Mines Information Circular 8179, "Safety
Recommendations for Sensitized Ammonium Nitrate Blasting Agents," or
(b) Where pneumatic loading is employed, before any type of blasting
operation using blasting agents is put into effect, an evaluation of the
potential hazard of static electricity shall be made. Adequate steps,
including the grounding and bonding of the conductive parts of pneumatic
loading equipment, shall be taken to eliminate the hazard of static
electricity before blasting agent use is commenced.
(c) Pneumatic loading equipment shall not be grounded to waterlines,
airlines, rails, or the permanent electrical grounding systems.
(d) Hoses used in connection with pneumatic loading machines shall be
of the semiconductive type, having a total resistance low enough to permit
the dissipation of static electricity and high enough to limit the flow of
stray electric currents to a safe level. Wire-countered hose shall not be
used because of the potential hazard from stray electric currents.