Section R11-1-262. Mixing plant,” located on mine property

A.       At each mining operation where field-mixed ammonium nitrate-fuel oil blasting agents are being used, all mixing shall be done under the supervision of competent personnel, duly instructed in the proper mixing of the blasting agent involved.

B.       Mixing plants shall conform to the requirements of this Sec- tion unless otherwise specifically approved by the Inspector.

C.       Mixing plants shall be located, with respect to the inhabited buildings, passenger railroads, and public highways, in accor- dance with the American Table of Distances. One-half the quantity of unmixed ammonium nitrate shall be included with the quantity of finished product, the total of which shall be considered as explosive, for determining the proper distances.

D.       A mixing plant building shall be of noncombustible construc- tion or sheet metal on wood studs.

E.       The layout of a mixing plant building shall be such as to pro- vide physical separation between the finished product storage and the mixing and packaging operations.

F.       Floors in a mixing plant building shall be of concrete. Con- crete floors must have at least one inch of finished cement, Terra Cotta finish, or other material approved by the Inspector. Floors shall be constructed so as to eliminate open floor drains and piping into which molten materials could flow and be con- fined in case of fire. The floors and equipment of the mixing and packaging room shall be washed down or cleaned when necessary to prevent accumulation of oxidizers or fuels and other sensitizers.

G.      Isolated fuel storage shall be provided at fixed plants to avoid contact between molten oxidizer and fuel in case of fire.

H.      The mixing plant shall be well ventilated.

I.         Heat, if needed, shall be provided exclusively from a unit out- side the building.

J.        All electric switches, controls, motors, and lights, if located in the mixing or blasting agent storage area, must conform to the requirements of Class II, Division 2, of the most recent edition of the National Electrical Code. The frame of the mixer and all other equipment that may be used must be electrically bonded together and be provided with a continuous path to ground which is separate from the ground provided for power equip- ment.

K.       The design of the mixer shall minimize the possibility of fric- tional heating, compaction, and especially confinement. All bearings and gears should be mounted outside the mixer and protected against the accumulation of product dust. All sur- faces must be accessible for easy cleaning.

L.       Mixing and packaging equipment shall be constructed of materials compatible with the ammonium nitrate composition.

M.      All discarded empty ammonium nitrate bags and other trash must be disposed of daily by burning outdoors.

N.       All sacks or containers used for storage of blasting agents must be properly marked and must show the mixing date.

O.      Blasting agents used underground shall be mechanically mixed in order to ensure a homogeneous mixture of the proper composition, but the mixing shall not be done underground.

Historical Note

Former Rule 2:62.