Arizona Administrative Code › Title 11 - MINES › Chapter 1 - STATE MINE INSPECTOR › Article 2 - EXPLOSIVES AND BLASTING › Section R11-1-262 - "Mixing plant," located on mine property

Current through Register Vol. 30, No. 28, July 12, 2024
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 Section 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 accordance 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 construction or sheet metal on wood studs.
E. The layout of a mixing plant building
				shall be such as to provide physical separation between the finished product
				storage and the mixing and packaging operations.
F. Floors in a mixing plant building shall be
				of concrete. Concrete 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 confined 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 outside 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
				equipment.
K. The design of the
				mixer shall minimize the possibility of frictional heating, compaction, and
				especially confinement. All bearings and gears should be mounted outside the
				mixer and protected against the accumulation of product dust. All surfaces 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.