The blaster in charge is responsible for all
aspects of explosives use and must:
(1) Carry a current license with the correct blaster classification
for the type of blasting being performed.
(2) Comply with all federal, state, and local government regulations.
(3) Meet the general license qualifications identified in WAC 296-52-64020,
General qualifications.
(4) Use every reasonable precaution to ensure the safety of the general
public and workers. Reasonable precautions include the use of:
(a) Blast area surveys.
(b) Warning signal posters, which must be posted in suitable
locations. Table T-1 shows the information that must be on
the poster.
TABLE T-1
warning signal
A 1 minute series of long blasts 5 minutes prior to
blast signal.
blast signal
A series of short blasts 1 minute prior to the shot.
all clear signal
A prolonged blast following the inspection of the
blast.
(c) Flags and barricades.
(d) Blasting mats or other suitable protective material.
(5) Exercise and apply independent professional judgment regarding
blasting activities, when following instructions from others could result
in an illegal act or affect the outcome of a blast.
(6) Blast operation activities. The blaster in charge must:
Have authority over all blasters and be able to promptly
correct all actions taken in any area of the blast operation
Manage the blast operation properly for any type of blasting
being performed
Control blast activities associated with a blast
Supervise explosive material activities, which include:
Keeping a running inventory of all explosives and
blasting agents stored at the blast area
Supervising all on-site transportation, storage,
loading, and firing of explosives
Notify local jurisdictions when blasting may affect them
Designate safe locations for personnel during the blast
Designate a method to determine when all personnel are
accounted for in designated safe locations
Make sure blast observers are able to communicate with
the blaster in charge
Make sure all possible exits to the blast site are observed
immediately prior to each blast
Distribute explosives in the shot
Be present when a charge is detonated
Personally detonate the charge or give an order to a designated
blaster to detonate the charge
(7) Notification - Blast incidents. The blaster in charge must
notify the department within 24 hours when:
(a) A misfire isn't cleared
(b) Vibration and air blast limits cause injury or property
damage
(c) Flyrock causes injury or property damage
(8) Blast records. The blaster in charge must:
(a) Keep an accurate inventory of all explosives and blasting
agents stored at the blast operation
(b) Keep a blast record with the following information:
Name of the company
or contractor
Exact location
of the blast
Date and time of
detonation
Name, signature,
and license number of the blaster in charge
Type of material
blasted
Type of explosives
used
Number of holes,
burden, and spacing
Diameter and depth
of holes
Total amount of
each type of explosives used
Maximum amount
of explosives per delay period within 8 milliseconds
Maximum number
of hole per delay period within 8 milliseconds
Method of firing
Type of circuit
Direction, distance
in feet, and identification of the nearest dwelling, house,
public building, school, church, or commercial/institutional
building not owned or leased by the blaster in charge conducting
the blasting
Weather conditions
Type and height
(or length) of stemming
A statement indicating
whether blast mats or other flyrock protection were used
Type of initiation
system used
Type of delay periods
used
Seismograph records and readings, if required or used,
must accurately identify the:
Name of the person
and business analyzing the record
Exact location
of the seismograph
Distance of the
seismograph from the blast
Sketch of the blast pattern. The sketch must include the:
Number of hole
Burden
Spacing distance
delay pattern
Sketch of the hole
profile if decking was used
General comments
which include:
Unusual conditions/situations
during the blast
The calculated
scale distance number
Misfires
Complete and sign
each blast record
Retain blast records
for a minimum of 3 years
Make sure blast records are available for department inspection.
Note: A nonmandatory sample blast record
can be found in Appendix B. You may use this format or create
your own but all the information in this section must be included.
Be handled by only competent and authorized personnel
Be delivered and issued only to a purchaser or a purchaser's
authorized agent
Be delivered into authorized magazines, approved temporary
storage, or handling areas
Be carried to the blast site from the main storage magazines
by the blaster or blaster's helper in special insulated containers,
day boxes, or original U.S. DOT shipping containers
Never be carried in pockets or clothing, including detonators.
(1) Dust storms. Blasting operations must be completely stopped
and all personnel removed from the blast area if a heavy dust storm
approaches or is present because it could cause static lightning.
(2) Thunderstorms. Blasting operations must stop and all personnel
be removed from the blast area if a thunderstorm approaches or is present.
WAC
296-52-67060 Extraneous electricity and radio frequency (RF) transmitters.
Precautions must be taken to prevent unintended electric detonator
discharge from extraneous electricity and radio frequency (RF) transmitters.
The following are sources of common hazards for extraneous electricity
and RF transmissions:
(1) Extraneous electricity. Common hazardous sources of extraneous
electricity include:
Adjacent power lines
Dust storms
Lightning storms
(2) RF transmission sources. Common hazardous sources of RF
transmissions include:
Mobile transmitters
Citizen band (CB)
Side band radio
VHF (FM) radio
UHF cellular telephones
Radar
Fixed location transmitters
Base stations for CB
Side band or FM radio communications
UHF cellular telephone transmitters and service extension
repeater systems
AM and FM (commercial) radio broadcast transmitters
TV broadcast transmitters and repeater system transmitters
Surface scan and radio navigation beacons
Low flying aircraft (in particular military aircraft)
create the most common serious RF exposures. These highly unpredictable
mobile transmitters are very powerful and transmit on a broad
spectrum of frequencies, which include, but are not limited
to:
Radar
Laser
All common communications bands
Note: The two most dangerous examples are:
Low flying automatic terrain following guidance systems
Airplanes which are equipped to jam all common radar and
communications frequencies for a distance of several miles
around the airborne transmitters.
(3) Transportation. Transportation of explosives must meet these
requirements:
Public highways. The Washington utilities and transportation
commission (UTC) and Washington state department of transportation
(WSDOT) require compliance with ANSI D6.1-1988, Uniform Traffic
Control Devices
Private roads.
You do not have to comply with ANSI on private roads under
department jurisdiction if required warning signs are properly
placed when electric detonators are present
(4) Site survey. The blaster in charge must conduct or assign
a designated appointee to conduct an accurate survey of the entire blast
area, to determine:
The clearance points where roads or right of ways enter and
exit the required clearance zone
If the 1,000-foot clearance zone needs adjusting to maintain
the permissible clearance zone at all times, if the blast area
moves as the job progresses
(5) Clearance zones.
Required clearance zones for:
Number of feet
Construction operations
1000 feet
Demolition operations
1000 feet
General industry operations, not subject to construction
Requirements
350 feet
(6) RF-transmitter warning signs.
F-TRANSMITTER WARNING SIGNS
(a) RF-transmitter warning-sign specifications.
Signs must:
Be a specific size. See the signs above for sign dimensions
Have a “construction” orange background
Have black letters and borders
Use all upper case letters that are at least the size shown
above
Note: Larger signs may be required where the highway speed
limit is more than fifty-five miles per hour.
(b) Posting warning signs must:
Be adequately placed to warn:
All transmitter users against the use of:
Radio frequency transmitters
CBs
Mobile phones
2-way radios
All users of routes into the electric detonator clearance
zone
Be prominently displayed when an electric detonator initiation
system is being used during blasting operations and when the
electric detonators have been removed from the original U.S.
DOT approved shipping container
Be posted at the beginning of the blast zone minimum clearance
point saying:
“turn
off cb, mobile phone, 2-way radio”
(c) Blast zone signs.
The “blast zone 1,000 feet” sign must be posted
one thousand feet before the “turn off cb, mobile phone,
2-way radio” sign
The 1,000 foot separation distance limit may be reduced
(not less than 300 feet) in very slow vehicle travel zones
(such as off-road construction right of ways, rock pits, or
quarries)
(d) An “end
blast zone” sign must be posted outside the blasting
zone clearance limits.
(e) Signs must be covered or removed when blasting operations
are not being conducted.
(7) Voltage identification. Electrical transmission and distribution
line voltage must be accurately identified.
(8) System clearance identification. The required clearance
for each system must be accurately identified.
(9) RF transmitters. Mobile RF transmitters must be deenergized
or disconnected when they're less than 100 feet from electric
detonators that are not fully contained in their original U.S.
DOT shipping containers.
Note: Fixed location RF transmitters represent
a higher level of hazard to both storage and blasting operations involving
electric detonators because the transmitters are more powerful and transmit
dangerous levels of RF exposure over much greater distances.
(10) Prevention of radio frequency hazards:
(a) Electric detonators in storage or at blasting operations must meet
the appropriate distance table requirements published in the IME Publication
Number 20, 1988, “Safety Guide for the Prevention of Radio Frequency
Hazards in the Use of Commercial Electric Detonators (Blasting Caps).”
(b) If it is necessary to conduct blasting operations inside the required
separation distances specified in the IME Pamphlet Number 20, 1988:
Storage and use of electric detonators is prohibited on
the site
Only detonating cord, safety fuse, shock tube, or other
approved nonelectric systems can be used.
Either Table 8-A or Table 8-B can be used to determine the maximum
limits of ground vibration for any dwelling, public building,
school church, commercial site, cofferdams, piers, underwater structures,
or institutional building nearby the blasting site. The methods used
for monitoring vibration and calculating frequency must be included
in the blast plan.
Table 8-A peak particle velocity limits
Distance from blasting site
Maximum allowable peak particle velocity1
0 to 300 ft (91.4 m)
1.25 in/sec (31.75 mm/sec)
301 to 5000 ft (91.5 m to 1524 m)
1.00 in/sec (25.4 mm/sec)
5001 ft (1525 m) and beyond
0.75 in/sec (19 mm/sec)
1 Peak particle velocity must be
measured in three mutually perpendicular directions
and the maximum allowable limits must apply to
each of these measurements.
(a) Frequency versus particle velocity graphics. In lieu
of Table 8-A, a blasting operation has the option to use
the graphs shown in Figure 8a or 8b to limit peak particle
velocity based upon the frequency of the blast vibration.
If either of the graphs in Figure 8a or 8b is used to limit
vibration levels, the methods used for monitoring vibration
and calculating frequency must be included in the blast plan.
Figure 8a
Alternative
Blasting Level Criteria
(b)
Scaled distance equations. Unless a blasting operation uses
a seismograph to monitor a blast to assure compliance with
Table 8-A or Figures 9a or 8b, the operation must comply
with the scaled distance equations shown in Table 8-B.
Table
8-B
Scaled-Distance
Equations
Distance from Blasting Site
Scaled Distance Equation
0 to 300 ft (91.4 m)
W (lbs) .= (d (ft)/50)2 or W (kg) .= (d (m)/22.6)2
301 to 5000 ft (92 m to 1524 m)
W (lbs) .= (d (ft)/55)2 or W (kg) .= (d (m)/24.9)2
5001 ft (1524 m) and beyond
W (lbs) .= (d (ft)/65) or W (kg) .= (d (m)/29.4)2
Key:
W .= The maximum weight of explosives in pounds
(or kilograms) that can be detonated per delay
interval of 8 milliseconds or greater.
d .= The distance in feet (or meters) from the
blast to the nearest dwelling, public building,
school, church, commercial, or institutional
building not owned, leased, or contracted by
the blasting operation, or on property where
the owner has not given a written waiver to the
blasting operation.
Note: To convert English Units of scaled distances
(ft/lb2) to metric units (m/kg2) divide by a
factor of 2.21.
(2) Air blast - Maximum limits. Air blast must not exceed
the maximum limits listed in Table 8-C. Use Table 8-C to determine
maximum air blast limits at any dwelling, public building, school,
church, commercial, or institutional building not owned, leased,
contracted, or on the property where the owner has not provided
a written waiver to the blasting operation.
Table 8-C air-blast limits
Lower
Frequency of Measuring System in Hz
(.+
or - 3 decibels)
Measurement Level in Decibels
0.1 Hz or Lower
Flat Response
134 Peak
2 Hz or Lower
Flat Response
133 Peak
6 Hz or Lower
Flat Response
129 Peak
C-Weighted
Slow Response
105 Peak dBC
(3) Flyrock outside the blast area:
(a) Uncontrolled flyrock. Flyrock traveling in the
air or along the ground can't be cast from the blast area in
an uncontrolled manner, which could result in personal injury
or property damage. Uncontrolled flyrock (airborne or along
the ground), that could cause personal injury or property damage,
isn't allowed from the blast area.
(b) Contract or written waiver. Flyrock can't be propelled
from the blast area onto property where the blasting operation
has not contracted or received a written waiver from the owner.
(c) Use of protective material. When blasting in
congested areas or close to a structure, railway, highway,
or any other installation that could be damaged, the blast
must be covered, before firing, with a mat or other protective
material that will prevent fragments from being thrown.
(i) When there is danger of drilling into a charged or
misfired hole.
(ii) Until all remaining butts of old holes are examined
for unexploded charges.
(b) Unexploded charges must be refired before work proceeds.
(2) Distance limits during drilling. Blasters can't load
or use explosives closer than:
(a) The length of the steel being used for drilling
OR
(b) Within 50 feet of drilling operations, whichever is greater.
(3) Prior to loading drill holes.
(a) Holes must be checked prior to loading to determine
depth and conditions.
(b) Drill holes that have contained explosives or blasting
agents can't be deepened.
(c) Drill holes must be large enough to allow unobstructed
or free insertion of explosive cartridges.
(4) Enlarging or springing a drill hole.
(a) A drill hole can't be sprung when it is near a loaded hole.
(b) A minimum of 2 hours must pass after a charge has exploded
in a drill hole that was enlarged or “sprung,” before
loading another charge of explosives into the hole.
Note: You don't have to wait 2 hours if
the sprung hole is thoroughly wet down with water before it is
loaded.
(c) Flashlight batteries can't be used as a power source for
springing holes.
(1) Power lines and portable electric cables. Power lines and
portable electric cables must be kept at a safe distance from explosives
or blasting agents being loaded into drill holes.
(2) Equipment, machinery, and tools.
Any machine or tool not being used to load holes must be
removed from the immediate loading area
Equipment cannot be operated within 50 feet of loaded holes
except when:
It is needed to add burden or mats
Tracking drills out of the loading area
(3) Holes that may be loaded. Only holes that will be fired
in the next blasting round may be loaded.
(4) Tamping.
(a) A primer must never be tamped.
(b) Tamping must be done with wood rods or approved plastic
tamping poles that don't have exposed metal parts.
(c) Nonsparking metal connectors may be used for jointed
poles.
(d) Violent tamping must be avoided.
(5) Pneumatic loading. When loading blasting agents pneumatically
over primed boosters:
A semiconductive delivery hose must be used
Equipment must be bonded and grounded
(6) Stemming. All blast holes in open work must be stemmed to:
(a) The collar.
or
(b) A point, which will confine the charge.
(7) Attendance of holes. Loaded holes must be attended or protected.
(8) Unused explosives. After loading, all remaining explosives
and detonators must be immediately returned to an authorized magazine
or day box.
(i) The blaster in charge must provide adequate on-the-job
training and supervision in the safe use of initiation
systems.
(ii) All members of the blasting crew must be instructed,
by the blaster in charge, in the safe use of the initiation
system to be used and its system components.
(b) Manufacturer recommendations. All initiation
systems and system components must be used in accordance
with manufacturer recommendations and instructions.
(c) Vehicle use precautions.
(i) Explosives bulk trucks or other vehicles operated on
a blast site can't tread on:
(A) Tubing
(B) Connectors
or
(C) Any surface delay component
(ii) If a vehicle must pass over loaded blast holes. Precautions
must be made to consolidate tubing, connectors, or any
surface delay component at the collar of the hole to prevent
vehicle contact.
(d) Connecting the firing line. Firing lines can't
be connected to the blast initiating device until all personnel
are:
(i) Accounted for
(ii) Removed from the blast danger area
or
(iii) Are in a blast shelter or other location that provides
equivalent protection
(e) Visual inspection. The blaster in charge must
visually inspect the initiation system to make sure it is
assembled according to the manufacturer's recommendations,
before firing the shot.
(f) Explosives not used:
(i) Unused detonators or short capped fuses can't be placed
in holes that may be used for blasting.
(ii) Unused detonators must be removed from the work area
and disposed of or stored in a licensed magazine.
(iii) Loose cartridges of explosives, detonators, primers,
and capped fuses that aren't used by the end of the work shift
must be returned to and locked in their magazines.
(2) Nonelectric initiation systems.
(a) Shock tube lines. When a nonelectric shock tube
initiation system is used:
(i) Spools of shock tube lines can't be spooled from trucks
or equipment.
(ii) The shock tube line must:
(A) Be free of knots and tight kinks
(B) Be free of cuts or abrasions that could expose the
core to moisture
(C) Not be stretched
(D) Be neat and orderly
(iii) Tie ins must be kept neat and clean.
(iv) Unused lead line must be sealed to prevent moisture
and dirt from entering the tube.
(v) Care must be taken to avoid hitting the tube with
a shovel when the shock tube is being covered.
(vi) The end of the detonator must be pointed toward the
front of the shot to minimize the chance of shrapnel flying
to the rear of the blast where the shock tube will be lit.
(i) Be secured properly in surface connector blocks.
(ii) Never exceed the rated capacity of tubes in surface
connector blocks.
(c) Splicing line. A knot must be tied in the tubes
to take the strain off of the splice.
(d) Detonator cord. If a detonator cord is used
for surface tie in:
(i) All lines must be kept taut.
(ii) Connections to nonelectrical units must be at 90 degree
angles.
(e) Equipment and personnel.
(i) Equipment can't roll over shock tubes.
(ii) All unnecessary equipment and personnel must be removed
from the blast area during loading.
(3) Electric initiating systems.
(a) Survey of extraneous currents. A survey to evaluate
extraneous currents must be conducted:
(i) By the blaster in charge before adopting any system of
electrical firing.
(ii) To eliminate all currents before holes are loaded.
(b) Detonator compatibility, style, function, and manufacture.
In any single blast using electric detonators, all detonators
must be:
(i) Compatible with each other.
(ii) Of the same style or function.
(iii) From the same manufacturer.
(c) Wire capacity and gauge.
(i) Connecting wires and lead wires must:
(A) Be insulated single solid wires with sufficient current
carrying capacity
(B) Not be less than 20 gauge (American wire gauge) solid
core insulated wire
(ii) Firing line or lead wires must:
(A) Be made of solid single wires with sufficient current
carrying capacity
(B) Not be less than 14 gauge (American wire gauge) solid
core insulated wire
Note: Bus wires, depends on the size of
the blast, 14 gauge (American wire gauge) copper is recommended.
(d) Lead wires.
(i) Shunting. You must shunt the ends of lead wires
that will be connected to a firing device by twisting them
together before they're connected to leg or connecting wires.
(ii) Control. The blaster in charge must keep control
of shunted lead wires until loading is completed and the leg
wires are attached.
(iii) Attachment. Lead wires must be attached by the
blaster in charge when it is time to fire the shot.
(e) Detonator leg wires. Electric detonator leg wires
must:
(i) Be kept shunted (short circuited) until they are connected
into the circuit for firing.
(ii) Not be separated (except for testing) until all holes
are loaded and the loader is ready to connect the leg wires
to the connecting or lead wires.
(f) Circuits.
(i) Blasting circuits or power circuits must be used in electric
blasting and according to the electric detonator manufacturer's
recommendations.
(ii) Care must be taken to make sure an adequate quantity
of delivered current is available according to the manufacturer's
recommendations, when firing a circuit of electric detonators.
(iii) A power circuit used for firing electric detonators
can't be grounded.
(iv) The firing switch must be designed so the firing lines
to the detonator circuit automatically short circuit when
the switch is in the “off” position.
(v) The firing switch must be locked in the “open”
or “off” position at all times, except when firing
from a power circuit.
(g) Firing line insulation. The insulation on all firing
lines must be adequate and in good condition when firing electrically.
(h) Testing.
(i) The firing line must be checked at the terminals with
an approved testing device before being connected to the blasting
machine or other power sources.
(ii) The circuit, including all detonators, must be tested
with an approved testing device before being connected to
the firing line.
(i) Switch keys. The blaster in charge is the only
person who is allowed to have firing switch keys in their possession.
(j) Blasting machines. A nonelectric system must be
used if these requirements can't be satisfied:
(i) Blasting machines must be in good condition.
(ii) The efficiency of the blasting machine must be tested
periodically to make sure it delivers power at its rated capacity.
(iii) Responsible person.
The blaster in charge must be in charge of blasting machines
The blaster in charge must connect the lead wires to the blasting
machine and must fire the shot.
(iv) Connections.
When firing with blasting machines, connections must be made
according to the manufacturer of the electric detonator's recommendations
All connections must be made from the drill hole back to the
source of the firing current
Lead wires must remain shunted and not connected to the blasting
machine or other source of current until the charge is ready
to fire
The number of electric detonators connected to a blasting
machine can't exceed the blasting machine's rated capacity.
(v) Series circuit. In primary blasting, a series
circuit can't contain more detonators than the manufacturer's
recommended limits for electric detonators.
(vi) Circuit testing. A blaster in charge must
use blasting testers specifically designed to test circuits
to charged holes.
(vii) Blasting near power lines. Whenever lead
or blasting wires could be thrown over live overhead powerlines,
communication lines, utility services, or other services
or structures by the force of an explosion, care must be
taken to make sure:
(A) The total length of wires are short enough so they
will not hit the lines
(B) The wires are securely anchored to the ground
(C) The owners or operators of the utilities in the blast
area are notified
(viii) Disconnecting lead wires. After firing an
electric blast from a blasting machine, lead wires must be
immediately disconnected from the machine and short-circuited.
(a) Safety fuse and detonators, used for conventional
blasting, must be in the following:
(i) When extraneous electricity or radio frequency transmissions
make the use of electric detonators and wire systems dangerous.
(ii) When overhead electric transmission lines can't be deenergized
and there is danger that blasting wires may be thrown onto
the overhead lines during a blast.
(iii) For avalanche control hand charges.
(iv) For specialized applications when detonators and
fuses are more suitable than electric or other nonelectric
initiation systems.
(b) Mudcap charges. A detonator and fuse can't be used
for firing mudcap charges, unless the charges are separated
to prevent one charge from dislodging other charges in the blast.
(c) Drop fuse method. Dropping or pushing a primer
or any explosive with a lighted fuse attached is prohibited.
(d) Damaged fuses.
(i) Deteriorated or damaged fuses can't be used.
(ii) It is prohibited to hang fuses on nails or other
objects, which causes sharp bends in the fuse.
(2) Fuse length. Fuses:
(a) Must be cut long enough to reach beyond the collar of
the drill hole.
(b) Must be 3 feet or longer.
(3) Fuse burning rate.
(a) Safety fuse burning rates must be:
(i) Measured.
(ii) Posted in conspicuous locations.
(iii) Brought to the attention of all workers.
(b) A fuse must burn between 40 and 55 seconds per foot or
it can't be used.
(4) Blaster safety. When blasting with safety fuses, the length
and burning rate of the fuse must allow sufficient time for the blaster
to reach a place of safety.
(5) Fuse capping.
(a) Capping location. Fuses:
(i) Must not be capped in any magazine or near any possible
source of ignition.
(ii) Must be capped in a place designated for this purpose.
(iii) Must be capped at least 100 feet from any storage magazine.
(b) Fuse ends. Before capping a safety fuse, a short length
must be cut from the end of the supply reel to guarantee
a freshly cut end in each detonator.
(6) Crimpers.
(a) Design. The design of detonator crimpers used for attaching
detonators to safety fuses must be approved.
(b) Condition. Crimpers must be in good repair.
(c) Accessibility. Crimpers must be accessible for use.
(7) Waterproofing. The joint between the detonator and fuse
must be waterproofed with a compound for use in wet locations.
(8) Primers.
(a) Site selection. Primers must:
(i) Not be made in magazines or near possible sources
of ignition.
(ii) Be made in a place designated for this purpose.
(iii) Be made a minimum of 100 feet from any storage magazine.
(b) Making primers. When making primers:
(i) Make only enough for one day's use.
(ii) Only nonsparking skewers must be used for punching
the hole in the cartridge to insert the capped fuse.
(iii) A detonator can't be inserted in explosives without
first making a hole in the cartridge of proper size or using
a standard detonator crimper.
(c) Storage. Primers must:
(i) Be stored in a box type magazine.
(ii) Not be stored in magazines where other explosives
are stored.
(9) Hand lighting.
(a) No one may light more than 12 fuses at a time when hand
lighting devices are used.
(b) Two fuses may be considered one fuse when 2 or more grouped
safety fuses are lit as a single fuse by:
(i) An igniter cord
or
(ii) Other similar fuse lighting devices.
(c) When multiple detonators and blasting is done by hand lighting
methods, at least 2 people must be present.
(1) Cord selection. Care must be taken to select a detonating
cord consistent with the:
Type and physical condition of the drill hole
Stemming
Type of explosives used
(2) Handling. A detonating cord must be handled and used with:
The same respect and care given to other explosives
Care to avoid damaging or severing the cord during and
after loading and hooking up
(3) Calculating quantity and distance.
For quantity and distance purposes, a detonating fuse (up
to 60 grains per foot) should be calculated as equivalent to
9 pounds of high explosives per 1,000 feet
Heavier cord loads should be rated proportionally
(4) Trunk lines.
Detonators for firing the trunk line can't be brought to the
loading area or attached to the detonating cord until everything
else is ready for the blast
All detonating cord trunk lines and branch lines must be
free of loops, sharp kinks, or angles that direct the cord
back toward the oncoming line of detonation
Truck lines in multiple row blasts must make one or more complete
loops, with cross ties between loops at intervals less than
200 hundred feet.
(5) Connections.
(a) Detonating cord. All detonating cords must be:
(i) Competent and positive in accordance with the manufacturer's
recommended specifications.
(ii) Kept at right angles to the trunk lines.
(iii) Inspected before firing the blast.
(b) Knots.
(i) Knot or other cord-to-cord connections must be made
with a detonating cord where the explosive core is dry.
(ii) All detonator cord knots must be tight.
(c) Connecting detonators.
(i) A detonator or electric detonator must be taped or
securely attached along the side or end of the detonating
cord. The detonator end containing the explosive charge
must be pointed in the direction of the detonation.
(ii) Manufacturer's recommendations must be followed when
short interval delay electric detonators are used with
a detonating cord.
(iii) Manufacturer's recommendations must be followed
when detonating cord millisecond delay connectors are used
with a detonating cord.
(iv) The line of detonating cord extending from a drill
hole or a charge must be cut from the supply spool before
loading the remainder of the drill hole or placing additional
charges.
(1) A code of blasting signals, equivalent to Table T-1, must be posted
in one or more conspicuous places at the blast area and all employees
must familiarize themselves with the code of blasting signals and use
it. Warning signs must be placed at suitable locations, see WAC 296-52-67075(1),
Warning signs.
(2) All charges must be covered with blasting mats or other protective
material before firing, where blasting may cause injury or damage by
flying rock or debris.
(3) Before a blast is fired, the blaster in charge must give a loud
warning signal after they have verified all surplus explosives are in
a safe place and all employees, vehicles, and equipment are at a safe
distance or under sufficient cover.
(4) Flaggers must be safely stationed on highways that pass through
the danger zone, to stop traffic during blasting operations on highways
that pass.
(5) The blaster in charge must set the time of the blast and
conduct all blasting operations so no shots will be fired without
their approval.
TABLE T-1
warning
signal
A 1 minute series of long blasts 5 minutes prior
to blast signal.
blast signal
A series of short blasts 1 minute prior to the
shot.
all clear
signal
A prolonged blast following the inspection of the
blast.
(1) Immediately after firing. Immediately after firing,
the blaster in charge must:
(a) Disconnect the firing line from the blasting machine.
(b) Lock the power switches in the “open” or “off”
position.
(c) Carefully trace all wires and search for unexploded charges.
(2) Post blast inspection. The blaster in charge must
perform an inspection of the area and surrounding rubble to determine
if all charges have been exploded before employees are allowed
to return to the operation.
(3) Misfires.
(a) Misfire found. Misfires must be:
(i) Immediately reported to their supervisor.
(ii) Recorded on the blast record.
(iii) Reported to the department within 24 hours if not cleared.
(b) Responsible person. A blaster in charge must be
present and direct the handling of all misfires.
(c) Termination of work.
(i) All work must stop, except activities needed to remove
the misfire hazard.
(ii) Drilling, digging, or picking is not permitted until:
(A) All misfired holes have been detonated
or
(B) The blaster in charge determines work can proceed
(d) Evacuation precautions. The following evacuation
precautions must be taken in the event of a misfire:
(i) If a misfire is found, the blaster in charge must make
sure safeguards are in place to keep all employees or other
personnel from the danger zone, except those needed to remove
the misfire hazard.
(ii) Workers can't return to misfired holes for at least:
(A) 30 minutes when electric blasting caps are used
(B) One hour when detonators and fuses are used
(e) Charged or misfired holes.
(i) Attempts can't be made to remove explosives from any
charged or misfired hole.
(ii) A new primer must be connected and the hole refired.
(f) Refiring hazard. If refiring a misfired hole presents
a hazard, explosives may be:
(i) Removed by washing out the explosives with water
or
(ii) Removed with air, if the misfire is under water.
(4) Burning holes.
(a) Everyone in the endangered area must move to a safe location
when explosives are suspected of burning in a hole.
(b) No one, under any circumstances, may return to the hole:
(i) Until the danger has passed
or
(ii) For at least one hour after the hole has been found.
(1) Receiving, handling, storing, and transportation.
(a) The blaster in charge or powder person is responsible for
the receipt, unloading, storage, and on-site transportation
of explosives and detonators.
(b) Explosives in transit can't be left unattended.
(c) Detonators and explosives for each round must be taken
directly from the magazines to the blasting zone and immediately
loaded.
(2) Wet holes. Explosives appropriate for use in wet
holes must be:
(a) Water resistant
and
(b) Fume Class 1 or other approved explosives.
(3) Bonding. All metal pipes, rails, air locks, and steel
tunnel linings must be:
(a) Electrically bonded together and grounded at or near the
portal or shaft.
(b) Cross bonded together at not less than 1,000-foot intervals
throughout the length of the tunnel.
(4) Air locks.
(a) No one is allowed to enter the air lock when detonators
or explosives are brought in, except:
(i) The blaster in charge.
(ii) The powder person.
(iii) The lock tender.
(iv) Employees needed to carry explosive materials.
(b) Primers, detonators, and explosives must be taken separately
into pressure working locks.
(c) Material, supplies, or equipment can't be brought into
air locks with explosive materials.
(d) Detonators and explosives not used after loading a round
must be removed from the working chamber before connecting the
connecting wires.
(5) Grounding. Each air supply pipe must be grounded at
its delivery end.
(6) Mixed face.
(a) Light charges and light burdens must be used for each hole
when tunnel excavation in rock face is approaching or is in
mixed face.
(b) Advance drilling must be done when tunnel excavation in
rock face approaches mixed face to determine the:
(i) General nature and extent of rock cover
and
(ii) Distance to soft ground as excavation advances.
Unless otherwise specified in this part, blasting agents must
be transported, stored, and used in the same manner as explosives.
Note: Water-gels are covered in WAC 296-52-67150,
Water-gel and emulsion explosives and blasting agents, through
WAC 296-52-67170, Bulk delivery/mixing vehicles.
(1) Building location. Buildings or other facilities
used for manufacturing blasting agents must meet the separation
distance requirements of Table H-21 for inhabited buildings, passenger
railroads, and public highways.
(2) Building construction. Buildings used for mixing
blasting agents must be constructed of noncombustible material
or sheet metal on wood studs and be well ventilated.
(3) Determining distance. When determining the distances
separating highways, railroads, and inhabited buildings from potential
explosions (Table H-20), the sum of all masses that may propagate
(i.e., lie at distances less than specified in Table H-22) from
either individual or combined donor masses are included in the
sum. However, when the ammonium nitrate is included, only 50 percent
of its weight must be used because of its reduced blast effects.
(4) Heat sources.
(a) Internal heating units. Properly designed and located
heating units that don't depend on combustion processes may
be used in the building.
(b) External heating units. All direct sources of heat
must be located outside the mixing building.
(5) Mixing plant floors must be made of nonabsorbent
materials such as concrete.
(6) Electrical equipment.
(a) Electrical switches, controls, motors, and lights located
in the mixing room must:
(i) Comply with the requirements of WAC 296-800-280.
(ii) Be located outside the mixing room.
(b) The frame of the mixer and all other equipment must be:
(i) Electrically bonded.
(ii) Provided with a continuous path to ground.
(7) Internal combustion engines.
(a) Location. All internal combustion engines used for
electric power generation must be:
(i) Located outside the mixing plant building.
or
(ii) Properly ventilated and isolated by a firewall.
(b) Exhaust systems. Engine exhaust systems must be
positioned so spark emission doesn't become a hazard to any
material in or adjacent to the plant.
(8) Mixing equipment. Equipment used for mixing blasting
agents must comply with the following:
(a) Design. The design of the mixer must:
Minimize the possibility of frictional heating, compaction,
and confinement
Have the bearings and drive assemblies mounted outside the
mixer and protected against the accumulation of dust
Have the surfaces accessible for cleaning
(b) Construction. Mixing and packaging equipment must
be constructed of materials compatible with the fuel ammonium
nitrate composition.
(c) Fire precautions. The following fire precautions
must be followed:
(i) Mixer fuel oil flow. In case of fire:
(A) Appropriate means to prevent the flow of fuel oil to
the mixer must be provided
(B) An automatic spring-loaded shutoff valve with fusible
link must be installed in gravity flow systems
(ii) Flame/spark producing devices. Smoking, matches, open
flames, spark-producing devices, and firearms (except firearms
carried by law enforcement bomb squad members or qualified
guards), are not allowed inside or within 50 feet of any facility
used for mixing blasting agents.
(9) Blasting agent compositions. The following are requirements
for determining blasting agent compositions:
(a) Determining sensitivity. The sensitivity of the
blasting agent must be determined by means of a Number 8 test
detonator at regular intervals and after every change in formulation.
(b) Handling precautions. Precautions must be taken
when handling:
Small particle oxidizers, such as crushed ammonium nitrate
prills or fines, may be more sensitive than coarser products
and must be handled with greater care
Solid fuels must be used in a manner to minimize dust explosion
hazards
Metal powders, such as aluminum, must be:
Kept dry
or
Stored in moisture resistant or weather tight containers
or bins
(c) Use restrictions. The following can't be used:
(i) Crude and crankcase oil
(ii) Hydrocarbon liquid fuel with a flash point lower than
the 125°F minimum for Number 2 diesel fuel oil
or
(iii) Peroxides and chlorates.
(10) Fuel oil storage.
(a) Facilities. Fuel oil storage facilities must be:
(i) Independent structures
or
(ii) Located at a site away from the manufacturing building.
(b) Surrounding area. In order to prevent oil from
draining toward a manufacturing building in the event of a tank
rupture, the surrounding grounds must slope away from the building.
(11) Safety precautions. Safety precautions at mixing
plants must include these requirements:
(a) Floor construction. Floors must be constructed
to eliminate floor drains and piping where molten materials
could flow and be confined, in case of fire.
(b) Mixing/packaging room. The floors and equipment
of the mixing and packaging room must be cleaned regularly and
thoroughly to prevent accumulation of oxidizers, fuels, and
other sanitizers.
(c) Housekeeping. The following housekeeping requirements
must be followed:
(i) Mixing plant. The mixing and packaging plant
must:
(A) Be cleaned regularly and thoroughly to prevent excessive
accumulation of dust
(B) Safely dispose of empty ammonium nitrate bags daily
(ii) Surrounding area. The land surrounding the mixing
plant must be kept clear of brush, dried grass, leaves, and
other materials for a minimum of 25 feet.
(d) Welding.
(i) Welding or open flames are not permitted in or around
the mixing or storage area of the plant unless:
(A) The equipment or area has been completely washed
and
(B) All oxidizer material has been removed
(ii) Before welding or repairing hollow shafts:
(A) Oxidizer materials must be removed from the inside
and outside of the shaft
and
(B) The shaft must be vented with a minimum 1/2-inch diameter
opening
(e) Explosives. Explosives are not permitted inside
or within 50 feet of any facility used for mixing blasting agents.
Note: This section applies to both off highway
operations and public highway transportation.
(1) Vehicles. These vehicle requirements must be followed:
(a) Strength. A bulk delivery vehicle must be strong
enough to carry a load without difficulty.
(b) Mechanical condition. A bulk delivery vehicle must
be in good mechanical condition.
(c) Body. A bulk vehicle body for delivering and mixing
blasting agents must:
(i) Be constructed of noncombustible materials.
(ii) Have closed bodies if they are used to transport bulk
premixed blasting agents.
(d) Mixing system parts.
(i) All moving parts of the mixing system must be designed
to prevent heat buildup.
(ii) Shafts or axles which contact the product must have
outboard bearings with a minimum of one-inch clearance between
the bearings and the outside of the product container. Special
attention must be given to the clearances on all moving parts.
(e) Welding.
(i) Welding or open flames are not permitted in or around
the mixing or storage area of the plant unless the equipment
or area has been completely washed and all oxidizer material
removed.
(ii) Before welding or repairing hollow shafts:
(A) All oxidizer material must be removed from the inside
and outside of the shaft
and
(B) The shaft must be vented with a minimum 1/2-inch diameter
opening
(2) Vehicle operation. Operation of bulk delivery and
mixing vehicles must comply with WAC 296-52-680, Transportation
of explosive material, U.S. DOT placard requirements, and these
requirements:
(a) Driver training. The vehicle driver must be:
(i) Trained in the safe operation of the vehicle, mixing,
conveying, and related equipment.
(ii) Familiar with the load being delivered and general procedures
for handling emergencies.
(b) Cargo and containers. Cargo and containers must:
(i) Haul either detonators or other explosives, but not both,
it is permitted on bulk trucks provided a
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