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Martin Marietta Aggregates ~
Martin Marietta Aggregates
Raleigh, North Carolina
'SCANNED
Safety in the use of explosives
These rules and regulations were developed to insure
the safety of our employees, on-site contractors, and
the general public and must be adhered to strictly.
They represent the composite standards of our employees,
explosives manufacturers, and regulatory agencies, and are
intended to be used in both surface and underground
operation.
Safety shall always be the first consideration in the use of
explosives. If a problem or question arises, contact your
supervisory personnel, the Martin Marietta Safety
Department and/or the Explosive Engineering Department.
Remember to never compromise safety for convenience of
the moment, have a simplicity of plan, and always use
common sense.
Martin Marietta shall retain responsibility for all
blasting regardless of whether done by Martin Marietta
personnel, others under supervision of Martin Marietta
personnel or by independent contractors.
Safety Department
Explosive Engineering Department
Martin Marietta Aggregates
Raleigh, North Carolina
Revised September 1995.
Table of Contents
6000 Definitions ....................................................... I
6100 Magazine storage ............................................. I
6200 Transporting explosives to the shot ................. 3
6201 Drilling .............................................................4
6202 Underground blasting ...................................... 5
6300 Stacking and distribution at blast area ............. 6
6301 Bulk explosives truck loading ......................... 6
6302 Loading the shot .............................................. 7
6303 Firing the shot .................................................. 9
6304 Misfires .......................................................... II
6305 How to prevent misfires ................................. 13
6306 Blasting in primary crusher ............................ 14
6307 Blasting during electrical storms ................... 15
6308 F1yrock ........................................................... 16
6309 Electric blasting ............................................. 17
6400 Sequential blasting ......................................... 18
6500 Non-electric blasting ...................................... 19
6600 Drilling inclined holes ................................... 19
6700 Basic blaster's rules ....................................... 19
6710 Special blasting .............................................. 21
6800 VibrationlAirblast - Seismograph use ............21
6810 Blast complaints .............................................22
6900 Required reports ............................................. 24
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Blasting Rules and Regulations
6000. Definitions
I. Blast area. The area of a blast within the influence of flying
debris, gases, and concussion from an explosion that may cause injury
to property and persons.
2. Blast site. The area where explosive material is handled during
loading, including a 50 feet perimeter formed by loaded blast holes.
In underground mines, 15 feet of solid rib or pillar can be substituted
for the fifty (50) feet distance. A distance of 30 feet may replace the
50 feet limit if the perimeter of loaded holes is marked with barriers
such as orange traffic cones. The 50 and 30 feet limit apply in all
directions along the loaded borehole length.
3. Blaster. That qualified person in charge of and responsible for
the loading and firing of a blast.
4. Delay PeriodlDelay Time. The time interval in milliseconds
between any two successively designed detonations within a blast.
5. Detonator. A device containing an explosive charge used to
initiate a detonation. These devices include electric and non-electric
blasting caps and delay connectors used with detonating cord.
6. Explosive Material. Includes explosives (dynamites and other
high explosives), water gels, emulsions, blasting agents, anfo, and
detonators (caps).
7. Flyrock. That rock or materials displaced out of the blast area,
quarry pit. or off the quarry property as a result of blasting.
8. Misfire. The complete or partial failure of explosive material to
detonate after an attempt at initiation. The term also is used to describe
the product itself. or the blast, or a part of the blast which failed to fire.
9. Primer. A unit. package, or stick of explosives which contains
a detonator (blasting cap) and is used to initiate other explosives
materials.
10. Shot. Term used to describe either the actual blast itself, or the
specific site where explosives are loaded or are to be loaded, or
muckpile produced by the blast.
6100. Magazine storage
I. No smoking, flame, or flame producing devices (matches,
lighters. welding units) shall be permitted within 100 ft;et of a
magazine or storage facility (trailer) containing explosive material.
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2. Magazines containing explosive materials must be checked each
working day. Any signs of forcible entry must be reported to the District
Office. Any theft of explosives must also be reported immediately to the
loca1law enforcement; the US Bureau of Alcohol, Tobacco, and Fireanns
(1-800-424-9555); and the Explosive Engineering Department.
3. All explosive materials (high explosives, water gels, emulsions,
blasting agents, anfo, and detonators) must be stored in magazines
constructed to BATF standards and located in compliance with MSHN
BATF regulations and permitting requirements.
4. No welding shall be done on any magazine unless explosive
materials are removed to a distance of at least 100 feet.
5. The area around the magazine must be cleared of all vegetation,
leaves, debris, or any flammable materials and small saplings less
than 10 feet in height, for a distance of 25 feet.
6. The magazines shall be kept clean, dry, ventilated, and in a good
state of repair.
7. Do not make interior repairs or move an explosives magazine
without first removing the contents and cleaning the inside. Prior to
exterior repair, all explosive materials stored within the facility shall
be removed if the possibility exists for a spark or flame. Materials
removed shall be placed a minimum of 100 feet from the magazine
and properly secured.
8. The magazine doors shall be padlocked with two five-tumbler
proof locks with case hardened 3/8 inch shackles in separate hasps
and eyes. Lock protectors shall be constructed with not less than 1/4
inch thick steel hoods so as to prevent forcible entry.
9. The magazines shall be locked at all times except when explosives
are being placed in or being removed.
10. Proper discipline, control, and security of magazine keys must
be exercised at all times.
II. Do not store detonators in the same magazine with other explosive
materials.
12. When anfo and other explosive materials are stored in the same
magazine, they shall be separated to prevent contamination.
13. No materials other than explosives, with the exception of a
broom and aluminum conveyors, are to be stored in the magazines.
14. Explosives shall be stacked so that the oldest stock can always
be accessed and used first.
IS. The location of any magazine or storage facility shall be identified
by the placing of four "Explosives" warning signs approximately 75
feet from each corner of the magazine, and so located that, in the event
they are fired upon, the projectile would not strike the magazine. No
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smoking signs shall be placed at any entrance area and no closer than
100' from the nearest storage facility.
16. No signs shall be placed on the exterior of the magazine.
17. When explosive n,ta!erials have deteriorated to an extent that they
do not resemble the o~gmal manufactured appearance, or leak liquid
(other than anfo weepmg), the Safety andlor Explosive Engineering
Department shall be notified.
18. Firearms shall not be allowed on sites where explosive materials
are stored or used. Law enforcement or security personnel are
excepted.
19. Explosives inventories and permits shall be maintained at each
office and in - out records kept in each storage magazine or facility.
20. A perpetual inventory must be accurately kept to coincide with
the physical inventory at all times and must be verified on a monthly
basis to the plant manager.
21. Only explosive materials purchased by Martin Marietta Aggregates
shall be stored on Martin Marietta property.
22. Facilities, such as trailers and bins, used to store blasting agents
shall be posted with the appropriate US DOT placards or other
appropriate warning signs that indicate the contents and are visible
from each approach. Any trailer storing anfo or other blasting agents
must have a king-pin locking device on the fifth wheel.
23. Powder chests (day boxes) shall be posted with the appropriate
US DOT placards or other appropriate warning signs. They must also
be emptied at the end of each day.
24. Any magazine, powder house, cap house, storage facility or
blasting agent trailer relocation of more than 100 feet must be
reported to the Explosive Engineering Department. Remember that
all explosive storage facility locations and types are recorded with
the company federal explosive permit and on file with BATE
6200. Transporting explosives to the shot
I. . Explosive material must be transported in a company approved
vehIcle, or one supphed by the explosives supplier. No loaders or
dozers shall be used for transporting explosives.
2. The vehicle used must be in safe operating condition, equipped
WIth two IO-pound mull1purpose dry-chemical fire extinguisher and
have "Explosives" and "No Smoking" signs displayed on the front,
rear, and both sides.
3. Explosives shall be transported in the rear storage compartment
or c~go space of the vehicle. The cargo space shall be free of all spark
creating tools, supphes, or other extraneous items, and lined with a non-
sparking material.
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4. The top height of the load (boxes or bags) shall not be higher than
the side boards or tailgate of the vehicle being used.
5. Explosive materials shall not be transported on public roads in
company owned vehicles.
6. Detonators may be transported in the same vehicle with other
explosives provided that they are separated from the other explosive
material by 4 inches of hardwood attached to the vehicle.
7. A vehicle transporting explosives must be attended at all times
and secured while parked by having the parking brakes set and the
rear wheels chocked.
8. A vehicle transporting explosives shall take the most direct low
traffic route between the magazine and the blast site and make no
stops at other facilities, such as shops or employee buildings.
9. No smoking is permitted within 100 feet of a vehicle loaded with
explosives.
6201. Drilling
I. The driller shall inspect the shot area to be drilled for:
a. Loose material in the face area rim which will not support the
weight of the drill.
b. Overhanging banks that present a danger of collapse.
c. Electric lines that pose hazard through contact with drill boom,
frame, or carriage.
2. Drilling is not allowed within 50 feet (30 feet barricaded) of a
loaded or partially loaded blasthole.
3. Boulder drilling shall not be done in the muckpile but only on
rock laid aside in a stable position so as to not fall on the driller or
equipment.
4. Drills shall not be positioned in unstable face areas where rock
slides from the bench could cause personnel or equipment to fall into
the pit.
5. When drilling underneath a high wall, a rule of thumb to follow
is that the drill boom should be set back along the bench 2 feet from
the wall for every 10 feet of wall height
6. It is sound practice to leave 20 feet of bench underneath any dead
(permanent) wall. This establishes an apron or buffer zone that
decreases the chance of rock falling on personnel and lor equipment
working on a lower bench.
7. Drill holes must be checked the day before scheduled bias thole
loading so that re-drilling or re-opening may be conducted, if necessary.
8. Angle drilling is not permitted unless approved by the plant
manager and production manager and supervised by the company
explosive engineer (or a designee).
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9. Personnel and equipment shall not work underneath loosely
appearing mud, dirt, rock, or large boulders where there is no buffer
or safety zone to prevent a hazardous slide.
10. Drillers shall maintain drill records indicating hole depth, rock
changes, and hole positions and shall communicate these conditions
to the blaster before blast hole loading commences.
II. Driller shall use safety lines and belts when drilling face holes
while working outside the drill cab.
12. When it is necessary to operate a drill at the blast site to re-open
(not re-drill) a blast hole, the blaster shall closely control every
movement and set up.
13. The driller shall move all drill equipment out of the immediate
blast area prior to blasting to insure against flyrock damage.
6202. Underground blasting.
I. Surface procedures in storing, transporting, and using explosive
materials apply as well to underground blasting unless indicated
otherwise.
2. Short modified blast reports may be used for documenting
underground face blast events. However, floor blasts shall be recorded
on company form 1-21.
3. Electric blasting operations shall be discontinued at the first
approach of a thunderstorm and personnel and equipment evacuated
from the blast area of the mine. That area shall be barricaded against
unauthorized entry.
4 The blast area underground may be defined as that area influenced
by gases, moving rock or debris as a result of an explosion that could
result in personal injury or equipment damage.
5. Non-electric blasting need not be suspended during thunderstorms
unless blasthole loading is near a mine entry or ventilation shaft that
could be impacted by a direct lightning strike.
6. Special care shall be given to use blow loading hoses that are
static resistant during pneumatic loading of anfo underground.
7. Electric operating equipment shall not be used within 100 feet
of the underground blast site.
8. All electric cap circuits shall be checked for continuity and
resistance upon completion of loading face rounds. All electric caps
must be checked before stemming is introduced, when loading floor
shots.
9. Special care shall be taken to keep detonators and explosives
separate while loading from the powder truck basket.
10. In underground storage, the same standard for housekeeping,
security, and record keeping is required as in surface magazines.
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6300. Stacking and distribution in the blast site
I. Where explosive materials or initiation systems are brought to
the blastsite, the area shall be barricaded and posted, or flagged
against unauthorized entry.
2. Explosives on the blast site shall be attended at all times.
3. Detonators shall be brought to the blast site in their original
containers or in company provided wooden boxes with the lids closed.
NO other material shall be carried in a container with detonators.
4. Detonators shall be kept separate from other explosives until
loading begins. The detonators may then be distributed by each hole
to ensure proper delay sequence. THEY shall be kept at least arms
distance from any explosive material when placed by a borehole.
5. Blasting agents, water gels, and emulsions may be stacked at the
bore holes during loading.
6. Primers, shall not be placed by the blast hole, but loaded into the
hole immediately after being made. (Remember that a primer is a
capped stick of explosives).
7. No explosive material, such as small cast primers, detaprimes or
detonators (blasting caps), shall be carried in personal clothing or
pockets.
6301. Bulk explosives truck loading
I. Bulk explosive materials shall only be discharged into blastholes
or non-sparking containers such as cardboard boxes or plastic pails
and not on any terrainal surfaces or waters on quarry property.
2. Fuel oil or chemicals shall not be allowed to spill from the bulk
truck.
3. Washing of non-company owned bulk explosive trucks is
prohibited on company property. Washing of mud and clay from truck
wheels is permitted.
4. All bulk explosive material delivery systems such as bulk trucks
shall have properly functioning metering devices that can indicate
fuel oil blend volumes and borehole loading volumes.
5. The bulk truck operator or blaster must keep a record of the
amount of material discharged into each hole.
6. The blaster shaIl continually tape each hole while augering
explosive product to monitor column rise.
7. All contractor supplied bulk trucks will be weighed upon entry into
the quarry before blast loading begins, and after loading has been
completed to insure accurate weights. Extra trips to the scales may be
necessary if different product densities at varying costs are used.
8. Bulk delivery trucks shall be maintained in good operating
condition and meet all MMA, local, state, and federal safety standards.
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9. Safety relief valves on bulk trucks pump systems shall be in proper
operating condition and of the proper pressure rating. Continually
rupturing relief valves or hoses indicate serious mechanical problems
and expedient repairs are not authorized.
10. Personnel are not allowed to work underneath bulk truck
discharge booms.
II. Shot loading personnel are not allowed to work in the space
between the bulk truck boom loading the first row of holes and free
face, if a falling or swinging boom could force someone to fall off
the high wall.
12. Bulk trucks shall not pass over any holes loaded with explosive
materials, and no part of the vehicle shall be allowed to come in
contact with any explosive materials laying about the blast site, or
any loaded or partially loaded blast hole.
6302. Loading the shot
I. All work during loading shall be supervised at all times by a
qualified blaster. When a blaster provided by the explosive supplier
is loading a shot, a Martin Marietta employee knowledgeable of all
company rules and regulations relative to explosives shall be on the
blast site at all times. If the Martin Marietta employee must leave,
blasthole loading must cease until that individual or another Martin
Marietta employee returns to the blast site.
2. Only person knowledgeable of blasting rules and regulations
shall be allowed on the blast site.
3. Whenever possible, shot loading should commence from the
front of the shot at the free-face proceeding to the rear.
4. Personnel or equipment shall not work in an area where a blast is
being loaded no closer than 50 feet (30 feet when marked by barrier)
unless such activity is directly related to blast hole loading.
5. When explosive materials have been introduced to blastholes on
a bench, the same 50 and 30 feet rule shall apply in respect to
muckpile digging. No loader or shovel operation shall occur within
these blast site perimeters in front of the face wall being loaded.
6. AIl blast holes shall be checked to determine the need for
clearing of obstructions or re-drilling before loading commences.
7. When it is necessary to move the drill over a loaded hole,
extreme care shaIl be taken to see that detonator leg wires, non-
electric signal tubes, or detonating cord are not run over, caught or
damaged. Except in this case, no equipment shall cross over or
operate on a loaded hole. In no case shall a drill re-enter a blast hole
containing any amount of explosive material.
8. Primers shall be made up at the hole where they are to be used
and immediately loaded into the hole. Do not throw detonator leg
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wires to uncoil them. Do not use the detonator shell to punch a cap
hole in explosives.
9. A blasthole loaded with an electric detonator shall be checked
with a blaster's ohmmeter or a blaster's multimeter prior to stemming
or decking.
10 Never use any instrument other than an approved blaster's
galvanometer, blaster's ohmmeter, or blaster's multimeter for electric
detonator testing. A standard multimeter can detonate an electric capl
circuit.
II. Detaprimes, or similar type small boosters, shall not be used to
prime anfo.
12. Blasting agents shall be primed strictly in accordance with the
manufacturers recommendations.
13. Tamping or dislodging of bridged or hung explosive material
shall be done only with non-sparking or wooden loading poles.
14. Primers shall not be tamped or forced past any obstruction in a
hole. Stemming material shall not be tamped.
15. No exposed metal other than a non-sparking type such as brass,
lead, or aluminum shall be put in a charged blasthole. Only cloth or
plastic tapes with lead plumb weights shall be used to measure blast
holes after explosive materials have been introduced.
16. Unused explosives shall be returned to magazines as soon as
practical after loading and before firing the blast.
17. A record shall be kept of all explosive material loaded into each
blasthole.
18. When pouring, pumping, or auguring explosive materials, column
rise shall be checked continuously. Discontinue loading if there is little
or no rise and take corrective action, such as decking through the faulty
area, before loading any more explosives in the borehole. Remember
such a condition can produce wildlv violent flyrock if soecial
technioues to ensure blast control are not used.
19. Unauthorized persons shall not be allowed in the blast area at any
time.
20. Areas where loaded holes await firing shall be guarded or
barricaded against unauthorized entry in accordance with all state and
federal regulations. Do not leave the blast site unattended.
21. Upon completion ofloading and connecting of circuits, firing of
blasts should occur without undue delay.
22. Do not handle explosives during the approach or progress of an
electrical storm. All persons in the blast area should retire to a safe
place upon the approach or progress of an electrical storm. Under no
circumstances shall anyone remain in the blast area after thunder or
lightning is perceived.
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23. Do not attempt to de-water a blasthole into which any explosive
material has been loaded.
24. Passing of trucks, loaders, or other equipment over loaded holes
is not permitted. In no case shall equipment (wheels, track, or body)
ever come in contact with or put pressure on any explosive material,
detonator legwire or shock tubing or any part of a charged blasthole.
25. If cartridges of explosives or blasting agents exceed 4 inches in
diameter, they shall not be dropped on the primer except where the
primer is covered by water to a height equal in length to the dropped
stick.
26. Blast holes shall be double capped when exceeding 30 feet in
depth.
27. Areas in which loading is suspended or loaded holes are awaiting
firing shall be attended, barricaded and posted, or flagged against
unauthorized entry.
28. If a stemming vehicle is used on the blast site, the operator must
be assisted by a guide to direct vehicle movement to a avoid running
over any blastholes, cap wires, or explosive materials; or striking or
touching such with any part of the equipment.
6303. Firing the shot
I. Warnings shall be posted at a highly visible area outside the
blast area fully describing blasting warning signals and whether or
not blast loading is in progress.
a. The blast warning signal- A series of short sirens lasting two
minutes. The blast may be initiated two minutes after the end
of the warning signal.
b. The all clear signal - One long siren lasting approximately
30 seconds - indicating that the blasting activity has been
completed and that it is safe to return to the pit or former blast
area.
c. The cancellation signal - a rapid series of short bursts of a
siren signaling the shot firer not to fire.
2. The warning signal may be sounded after ample time has
been allowed to accomplish the following security measures in the
blast area.
a. All equipment moved to an area not affected by rock throw.
b. All personnel warned of the planned blast and cleared from
the blast area.
c. All access routes leading into the blast area guarded or
barricaded to prevent entry of persons or vehicles.
d. Clear and unobstructed exit route provided for the shot firer.
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3. Firing - The blaster and/or shot firer may communicate by radio
or other visual signals with the person(s) designated to clear the blast
area and all blast area guards to assess the security of the blast area
in preparation for firing. The blasting machine shall not be connected
to the blasting system or circuit until the warning signal has been
sounded.
a. The warning signal shall be sounded in completion two
minutes before blast initiation after securing the blast area.
b. The blaster shall insure that the blast area continues to be
secure.
c. The shot firer shall make a final check of blasting circuits and
connect the blasting machine to the blasting system.
d. The shot may be fired two minutes after the warning signal.
if the blast area is secure, the blasting and initiation systems
properly check, and the cancellation signal has not sounded.
e. The all clear signal shall be sounded after the blaster and the
shot firer insure that the blast detonated correctly, smoke and
dust subsided, and no hazards such as potential rock fall exist.
4. Firing House
a. All blasts shall be detonated from a "shooting House" ap-
proved by the Explosive Engineering Department or Division
Maintenance Service (Salisbury Shop).
b. The shooting house must be located at least 200 feet in the
opposite direction of intended shot movement, behind the blast
and never to the front.
c. The shooting house shall not be located in view ofthe free face
of the blast site or at a point from a direction where flyrock
from the free face can travel.
d. The shooting house shall not be located near a face where a
cave-in or slide may occur, or toe of a high wall in an area
where a falling or bouncing rock might ricochet into the
blasting chamber.
e. The shooting house shall not be located within 200 feet of an
overhead electric transmission line, underground gas pipeline,
or fall zone of a large pole, or tower.
5. If a blast must be allowed to sleep overnight, secure the blast
site with barricades such as traffic cones, inform the production
manager and explosive engineer and position a guard person in view
of the blast area to protect continuously against unauthorized entry. The
guard shall know Martin Marietta rules and regulations concerning
safety and explosives.
6. No surface blast shall be fired after dark or at anytime where
there is not sufficient visibility to view the entire blast area.
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7. Blasting, either surface or underground, shall not be con-
ducted on weekends.
8. Blasts shall not be observed from a position in front of the face
being fired.
6304. Misfires
\. Misfires shall be handled by experienced persons approved by
the manager of explosive engineering and/or production manager.
Faces and muckpiles shall be examined for misfires after each blast.
When a misfire occurs, all personnel shall stay out of the blast area
for 30 minutes. This policy applies also to non-electric shut-down or
cut-offs.
2. Procedures for clearing a misfire are as follows:
a. If small amounts of explosive products (one or two sticks,
etc.)
1. Alert your immediate supervisor and Explosive Engineering.
2. Retrieve undetonated products and return to the magazine.
3. Warn loader/shovel operator and primary crusher operator
to watch for undetonated explosive materials.
4. Inform your explosive supplier.
b. If large amounts of explosive material and/or live charges
are found in a normal appearing muckpile, the following
action should be taken:
I. Access to the blast area shall be restricted by barricade and
a minimum number of personnel which can safely handle
the situation shall be allowed to enter the area.
2. The shovel or loader shall be stopped immediately from
digging in the shot in which a misfire appears to have
occurred.
3. The plant manager, production manager, and Explosive
Engineering Departtnent shall be immediately notified.
4. Digging shall not be resume? until the followin~ steps have
taken place and approval is given by the prodUCl1on manager
and/or Explosive Engineering Department.
5. Before resumption of digging, place a safety glass and s.creen
in front of the shovel or loader operator. If the glass IS not
available, one inch screen cloth should be placed across the
front of the cab and two inch screen cloth securely fastened
and so located to protect the operator from the sides.
6. An explosives technician, safety engineer, or~on cte.signa~d
by the production manager and/or ExplOSive Engmeenng
Departtnent shall be present at all times when digging in the
shot.
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7. All employees not required to work on the shot shall be
prohibited from the area.
8. The shovel or loader shall not dig directly into the front of .
a misfired hole, but from the sides.
.9. The drivers of the trucks to be loaded shall back their trucks
into the muckpile and park in such a way that the rear of the
truck protects the driver from the shot. The driver of the
truck should remain in the cab and shall not lean from the
cab to watch the operation.
10. If any explosive material is observed mixed with shot
rock in the loader/shovel bucket or truck bed, that material
shall be carefully dumped, sorted near the blast site, and
unexploded products removed for safe disposal.
I I. Undetonated explosive products must not be left laying
about unguarded, but shall be returned to the magazine.
12. Explosive materials recovered from a misfired shot shall not
be re-used as primary products but should be disposed of as
directed by the Explosive Engineering Department.
13. Plant personnel, especially primary crusher operators,
shall be instructed to keep a close watch for explosives. If
any explosives are seen in the feeder, crusher, or on the
screens or conveyors, the equipment must be stopped
immediately, and the blaster notified to undertake proper
retrieval and disposal.
c. If a maior misfire occurs. i.e. all or part of a blast did not
detonate, the following actions shall be taken:
I. The all-clear signal shall not be sounded.
2. All personnel must stay out of the blast area for 30 minutes.
Access to the blast area shall be guarded and barricaded.
3. Notify the plant manager, production manager, and
Explosive Engineering Department. Also notify your
explosives distributor.
4. All electrical detonators and circuits that are intact must be
checked with the appropriate testing devises. If a non-
electrical initiation system was used, a visual check must be
made of all surface detonators and lines.
5. If a sequential timer was used, the entire sequential system
should be checked both visually and with the appropriate
test equipment.
6. Careful consideration must be given as to whether or not
some holes are unburdened which may produce Dyrock
if re-fired. If- part of the wall of the blast is intact, a
potential exists for hazardous rock throw. Explosive
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Engineering Services shall advise management whether
or not the shot can be safely re-fired.
7. Ifre-firing is not acceptable, efforts must be made to access
and retrieve by blowing air to remove stemming or rock
debris or pouring water in the blasthole to neutralize the
explosive material. If these steps do not clear the misfire,
digging the shot may be the next course of action. All of
the aforementioned methods may be used to clear misfires.
In no case can a misfire be re-drilled without authorization
by the production mana~er and the Explosive Engineerin~
Department.
8. If digging is authorized, steps 4 thru 13 of paragraph
6304.3b shall be followed.
6305. How to prevent misfires
t. The best way to avoid misfires in either electric or non-electric
blasting is to use good blasting practices, and to be aware of what
causes such problems. The following are the most frequent causes
of misfires in Martin Marietta and subsequent corrective actions
to avoid their occurrence:
a. Defective wirine svstem: Thoroughly check, both visually
and with test equipment, the blasting machine, firing cable,
terminal board, and circuit wires. Strictly follow initiation
equipment manufacturer's recommendations; in most cases,
a blaster's galvanometer or blaster's multimeter is adequate
test equipment.
b. SlumoiDl! holes breakine detonator lel!wires or si~al tube:
Test each detonator and measure each hole for this condition
before stemming is introduced. Sometimes, an extra primer is
needed as insurance. If stemming has occurred, and cut-off is
evident, it shall be necessary to blowout the stemming to re-
prime.
c. Detonators not connected to the circuit: Visually check by
walk-through of the connected blasting circuits by the blaster.
d. Bare wire in water: Keep all bare wire connections out of
water or damp ground. Make certain that firing cable and
terminal board are in good condition and that moisture can not
enter the internal wiring circuit. If any damage is apparent to
the board or cable, return to the manufacturer for repair or
replacement.
e. Poor wire connection: Visually inspect 'all tie-ups and test each
circuit with proper test equipment. Know how to calculate
circuit resistance of each circuit.
f. Inadequate power source: Know the energy capacity of your
blasting machine and stay 20% below rated capacity in number
13
of detonators in a circuit. When using an REO Sequential
blasting system, if charge-up time takes longer than 25
seconds, Do Not attempt to fire before replacing batteries. If
things do not seem right, or equipment appears damaged, do
not attempt to fire. Strictly follow the manufacturer's operating
procedures. Take no short cuts!
g. Non-electric surface cut-offs: Follow the manufacturer's
instructions explicitly. Take precautions when stemming that
the shovel blades do not strike any part of the nonel trunkline.
Remember that the only method of checking this system is
visual, so carefully inspect your hook-up.
h. Current leakaee: This is usually caused by scraped wires in
wet conditions. Handle all detonator wires carefully. Use a
three post blaster's galvanometer or blaster's multimeter to
check for leaks, and limit the number of detonators per circuit
if current leakage exists. Do not tamp stemmin~ Study your
blasting multimeter instructions on how to check for leaking
currenl.
L Explosive product failure. Do not use any explosive
product if it appears defective or sub-standard. Remember
that detonators that are deformed, over aged, or have bare
wire may misfire. Ammonium nitrate without 6% diesel
fuel may not detonate. Emulsions that are crystallized may
not detonate. Water gels may not shoot under extremely low
temperature. All emulsions and water gels rarely have a
shelf life exceeding one year and become less sensitive to
detonation with age.
j. Poor timiDl!:/delav Dractices (electrical): In sequential
electric blasting, if all circuits are not energized, the possibility
exists for rock motion to cut off an un-energized circuit, thus
causing a "shut-down" or misfire. Only FAST (Fully Activated
Sequential Timing), not PAST (Partially Activated Sequential
Timing), shall be used. It is strictly required in Martin Marietta
for all sequential blasts circuits to be fully electrically "lit"
before the first charge detonates.
6306. B'astlng 'n pr'mary crusher
I. The use of explosives to clear "blocked" crushers is not a practice
that Martin Marietta Aggregates endorses. However, if no other
reasonable solution is available, the use of explosives will be allowed
if the following procedures are followed:
a. A cap-sensitive high explosive that is capable of performing
below 00 F must be used in a measured quantity (no more than
one-half of a 11/4 x 8 stick of product).
b. A non-electric detonator, such as a primadet no less than 60
feet in length, must be used in conjunction with a hand-held
14
non-electric starter. No electric detonators may be used due to
extraneous electric current hazards in the plant area.
c. All explosives must be kept in an approved magazine as
defined by MSHA and BATF standards. A day box meeting
strict BATF construction standards may be used to temporarily
store the small amounts used during the day. All unused
products must be returned to the magazine at the end of the
work shift.
d. All plant and loading operations within the blast area must
cease and all non-essential personnel must be cleared from the
area. Guards must be posted to prevent entry into the blast area.
e. A shooting house or equivalent protection must be provided
to the blaster. All personnel in the blast area must take
protected cover to ensure against flyrock.
f. Warning and all clear signals must be sounded as is done for
production blasts.
g. A brief blast report showing plant location, date, time. and
quantity of explosive materials used must be filled out after
each blast.
6307. B'asting during e'ectrica' storms
I. All electric and non-electric detonators are susceptible to pre-
mature initiation by lightning. The following policies are to be
observed while blasting.
a. Make sure someone keeps an eye on the local weather
conditions. Inform all personnel of blasting operations and
ask them to report thunderlIightning to a foreman. This is
particularly important in underground mines or deep pits
where surface weather conditions are not easily apparent.
b. Since thunderstorms tend to occur in the afternoon, schedule
blasting to be completed in the mornings, if possible.
c. When it is determined that a storm is imminent (Le., a
threatening cloud seen, thunder heard or lightning observed),
evacuate all personnel from the blast area to a position of
safety, immediatelv whether you are using an electrical or
non-electrical initiating system, and move the explosives
truck to a safe location. It is preferable to park the truck at
the nearest explosives magazine. If there is no magazine at
the quarry, make sure the truck is away from the office, shop,
plant, and all personnel. Keep access to the blast area and
storage area sealed off until the storm passes.
d. In electric blasting, the blaster should not wire-up until the shot
is loaded. However, if a storm is imminent and wiring of the
shot has begun and if there is time, open closed wire loops in
15
the blasting circuit, being careful to keep all bare wire off the
ground.
e. In non-electrical systems, disconnect any surface initiating
system attached to the downlines if time permits.
f. After the storm has passed, close or shunt all open wire circuits
immediately.
g. Underground electrical blasting shall be suspended and all
persons withdrawn from the blast area to a safe location during
the approach and progress of an electrical storm.
6308. F'yroclc . Causes and prevention
I. Flyrock is the major cause of death, injury and destruction of
property resulting from blasting. The following are causes and
subsequent preventive methods. Keep in mind that the possibility
exists for flyrock to happen on any shot, so do not hesitate to take
every measure for avoidance.
a. Overloading of holes: This practice is especially dangerous
and can never be tolerated. Normal powder factors should be
maintained at all times. The use of a measuring tape in every
hole to measure column rise is essential. Be particularly
diligent during bulk loading operations since rapid column
build-up is characteristic of auger and pump. Give priority
attention to all stemming heights at the crest on all free-faces.
b. Insufficient stemming: Too little and/or poor quality stemming
can lead to flyrock. Make certain that each hole is adequately
filled. Cleans tone works the best. When determining proper
stemming height, a rule to use is 25 times the borehole diameter
(i.e., 25 x 4 inches = 100 inches = 8 feet). Backfill unused
boreholes within a shot with stemming material to prevent
explosive gas venting from these holes.
c. Lack of burden: If the distance from a borehole to the free
face is too close, excessive flyrock may occur. Front row
minimum burden distances should be carefully monitored. Use
set-back marks, measure front row burdens, and decrease the
explosive load in weak areas of the wall. Normal powder
factors shall be maintained at all times. Rarely will rock fly if
the powder factor is above 1.5.
d. Lack of relief: Insufficient relief (too much burden) can create
an excessive upward thrust of rock being blasted. Rather than
the rock collapsing in sequence upon itself, it can follow the
path of least resistance straight up and back of the shot. Again,
set-back positions and proper measurement of burdens and
spacings are essential.
e. Improper delay patterns: Irregular hole delaying can render
any shot dangerous and unpredictable. Proper delay sequences
16
are essential for desired fragmentation and rock movement. Get
to know which delay patterns work best and pay close attention
to the delay design. Never allow less than 10 milliseconds
between any two adjacent fully loaded holes or less than 42
milliseconds between rows of holes. Never allow a higher
sequenced delay hole to detonate in front of a lower sequenced
hole, unless specifically intended for shot design purposes.
f. Weak geological rock structures: The blaster must begin every
blast loading operation by checking the drilling information
concerning the depth, condition, and position of each hole, and
carefully inspecting the face for signs of weak areas such as
cavities, cracks, joint planes, and clay seams. Decking to reduce
powder factor is a typical loading method that can control such
weaknesses of rock.
6309. E'ectr'ca' b'astlng
I. Never mix detonators of different manufacturers in a blast.
2. Do not operate a welding machine or any other electric motor
within 100 feet of an electric detonator. Do not blast within 100 feet
of any electric motor without authorization from Explosive Engineering
Department.
3. Portable radio equipment, such as two-way radios, or cellular
phones shall not be operated within 150 feet of the blast site.
4. When blasting within 1500 feet of radio transmission towers,
contact the Explosive Engineering Department.
5. When blasting within 500 feet of high power electrical transmission
lines and gas pipelines, contact the Explosive Engineering Department.
6. Keep all detonator leg wires shunted until you are ready to check
the detonators with a galvanometer, blaster's ohmmeter, or
blaster's multimeter. After checking the detonator, twist the bare
ends of the leg wires together and keep them so until ready to be
connected to a circuit.
7. When wiring up the blast, keep all connections, splices and bare
wires off the ground and out of water
8. Keep all wires, (including connecting and bus wire) whether
insulated or not, from contact with any metal objects, such as drills,
vehicles, and air and water lines. Do not allow spliced connections
in one circuit to come in contact with spliced connections of any
adjacent circuits.
9. No one, except the blaster or persons designated by the blaster,
shall be allowed to walk over the blast site after an electrical shot has
been wired; or in the case of a non electric shot, after the surface
delays are connected. Hook-up is not to begin until hole loading
and stemming is completed and the blast site is cleared of all
vehicles, equipment and non-essential personnel
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10. Blasting machines shall be tested in accordance with the
manufacturers recommendations before blasthole loading begins.
well away from the blast site.
II. Always use a blasters' multi meter, blasters' galvanometer, Or
blasters' ohmmeter to check the resistances of electric blasting
detonators and electrical blasting circuits. Never use an electrician's
multimeter on electric detonators.
12. Check all electric detonators with a blaster's muItimeter or
galvanometer before stemming
the blastholes.
13. When conditions exists for stray electric currents, check the
future blast site with a blasters multimeter. If stray current is present,
find and eliminate the source or use a non-electric initiation method.
14. After the initiation system hookup is completed, the blaster shall
"walk the shot" to inspect and double check all connections.
15. The blasting machine must be stored in a secure area separate
from all explosive materials and blasting caps and shall not be brought
to the firing point until immediately before time of use.
6400.Sequenffalblasffng
1. The sequential timer, all associated equipment, and all other
blasting machines shall be checked as soon as possible before
beginning to load any shot.
2. The sequential timer should be checked annually for energy
output and circuit timing accuracy. These checks can be done by the
Explosive Engineering Department or by an explosive representative
having a BTU 300-10 Tester.
3. New batteries shall be installed in the sequential blasting
machine when the charging time exceeds 25 seconds. Do not attempt
to fire a sequential timer if the charge time exceeds 25 seconds. A
misfire may occur.
4. When using a sequential timer to initiate a blast, the timing shall
be such that the first hole in the shot does not fire or detonate until
all the circuits/series are energized. This follows the principle of
FAST - Fully Activated Sequential Timing.
5. Sequential blasting cables may be repaired in the field in an
emergency in order to get a shot off, but then shall be returned to the
manufacturer for repair.
6. Damaged circuit boards shall be discarded or returned to
manufacturer for repair.
7. When designing a blast, do not exceed a total resistance in any
series or circuit of detonators of 80% of the capacity of the sequential
timer. For example, in an REO BM-125, one should not exceed 100
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ohms. When using a REO-BM-175, one should not exceed 140 ohms
in any single circuit
8. A spare circuit board and short cable shall be kept at each quarry
for backup use, in case of damage to the primary board and cable.
6500. Non-electric blasting
I. Non-electric (nonel) detonator must be used strictly in accordance
with the manufacturers instruction.
2. If electrical systems or equipment such as pumps, compressors,
transmission lines, or transformer stations exist within 200 feet of the
blast site, it may be necessary to use non-electric caps.
3. The non-electric starter machine and shot shell primers must be
stored in a secured area separate from all explosive materials and
detonators and not removed until immediately before time of use.
4. Surface connection of nonel systems is not to begin until
bias thole loading is complete and the blast site cleared of vehicles,
equipment, and non-essential personnel.
5. Special attention must be paid to nonel systems that have a low
strength delay cap on the surface end of a down hole detonator. These
initiators lay exposed on the ground during surface loading and must
be carefully avoided by vehicles, equipment and tools.
6600. Drilling InclIned holes
I. Due to the high incidents offlyrock accidents caused by inclined
holes, the practice of angle drilling of blastholes is not permitted in
Martin Marietta unless authorized by the plant and production
manager, and supervised by the Explosive Engineering Department.
6700. Basic blaster's rules
I. No smoking or open flames are permitted within 100 feet of any
explosive material, whether or not they are in storage, in transportation,
or in a bore hole stemmed or unstemmed.
2. In the event of an explosives fire, do not fight the fire. Evacuate
and secure the area. If a tire or engine fire can quickly and safely be
extinguished, do so.
3. Only approved blasters galvanometers, blasters ohmmeters, and
blasters muItimeters shall be used to test electrical blasting circuits.
4. Be alert for conditions that might cause flyrock.
5. Observe the drill pattern prior to loading. Study the wall for clay
seams, weak burdens, slips, and cracks.
6. Diagram the shot as drilled and design the delay pattern before
detonators are laid out.
19
7. Calculate powder factors prior to loading. Measure burden.
spacing, and depth. Check the drilling record. Talk to the driller about
any dust escaping to the face area.
8. Allow yourself ample time to load and fire the shots. Misfires
are caused by hurrying.
9. Check blasting machines and associated equipment prior to
loading the shot.
10. Make sure you understand the signal to fire the shot. If in doubt,
delay firing.
11. Always have adequate cover (shooting house) at the blasting
point.
12. Complete the blast report before leaving the quarry.
13. Always clean the blast site of bags, wire, boxes, hole plugs, and
extraneous debris prior to connecting up and firing the shot.
14. Keep the number of people to a minimum when loading and
connecting up. Idle people on a shot can be dangerous.
15. Assign duties to specific people during loading. Try to keep
yourself free to observe these duties.
16. Be certain stemming is adequate. Avoid using wet or muddy
stemming material. Crushed stone is recommended.
17. Always keep an eye on the weather and be ready to evacuate at
the first sign of a thunderstorm.
18. Use common sense.
19. Know your limitations. Do not hesitate to ask questions or
request assistance.
20. Keep a drill log on each hole as to depth, soft seams, cracks, loose
rocks, and any problems encountered.
21. Keep a blaster's log on each blasthole as to wall height, depth,
type and amount of explosives, water depths, burden/spacing, and
stemming heights.
22. Do not allow any explosive containers to leave the quarry
premises unless by the distributor's truck.
23. Check all containers to make sure there are no explosives in them
before the containers (boxes and anfo bags) are burned.
24. The empty explosive containers can be piled behind the blast site
and burned after the blast if local burning regulations allow.
25. No explosive material shall be destroyed except under the
supervision or direction of the Explosive Engineering Department.
26. The use of dynamite is not permitted.
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27. Always and Nevers should be read by all blasters. Copies of
Always and Nevers can be found in every box of detonators and
packaged explosive materials.
28. Do not blast after dark or on weekends.
29. In bulk truck operations, do not allow fuel oil to be discharged
on the ground.
30. Miners are not allowed to work between the front row of
blastholes and the edge of the free face without safety lines if that
distance is less than the individual's height or if the area appears
unstable.
6710. Special blasting
1. Specialized blasting such as pre-splitting, ditch-line shooting,
stream relocation, beaver dam blasting, close proximity blasting or
any activity not related to ordinary bench blasting SHALL NOT be
planned or conducted without the authorization and involvement of
the production manager and a Martin Marietta explosive engineer.
6800. Vlbraflon/Alrblasf.selsmograph use
I. The blaster shall keep in mind that explosive pounds per delay
and stemming are major factors in blast design influencing ground
vibration and airblast, and are the most frequent contributors of blast
vibration complaints. In order to protect Martin Marietta Aggregates
against possible legal action resulting from vibration damage claims,
the use of a seismograph to monitor blasts is strongly encouraged.
2. The use of a seismograph is required when:
A. Scaled Distance (Ds) factor is less than 60.
Whereas:
Ds = D/..JW
And D = distance in feet to nearest non-
company building
And..JW = square root of maximum weight of
explosive in pounds per-delay
B. Any blast complaint has occurred.
C. Mine permit dictates.
3. Seismic monitoring shall be done as close as possible to the non-
company owned building nearest the blast (with property owners
permission).
4. Seismographs shall be calibrated annually. It is the law in many
states.
5. Report all blast complaints using Form #1-3 to production
manager and Explosive Engineering Department.
6. Treat seismographs carefully, as fragile and expensive electronic
instruments.
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7. Report peak particle velocities (PPV) that exceed .5 inches per
second and airblast levels exceeding 127 decibel to the production
manager and the Explosive Engineering Department.
6801. Blast complaints
I. Due to public attitudes toward blasting, complaint handling has
become a frequent and difficult task in our industry. Since any
complaint has the potential to become a court case, it is essential that
supervisory personnel (including blasters), be trained to handle these
problems. Many times, the manner in which a complaint is first dealt
with paves the way to successful or unsuccessful resolution.
2. In handling blast complaints, the following guidelines shall be
followed:
A. Initial Telephone Contact
1.00:
a. Record on complaint form (1-3) all details requested.
b. Be a good listener.
c. Be courteous.
d. Encourage complainant to discuss circumstances.
e. Keep an open mind.
f. Ask to be allowed to seismograph on property.
g. Suggest a return call or visit by manager.
h. Promptly forward complaint to Explosives Engineering
Department.
2. DON'T:
a. Argue or become angry.
b. Demand an inspection.
c. Volunteer information.
d. Be the first to bring up any possibility of damage.
e. Take abuse - politely break-off the conversation.
B. Follow-up visit/call
1.00:
a. Review complaint report.
b. Review blast and seismograph report.
c. Review past complaints of this individual.
d. Be prompt.
e. Be a good listener.
f. Be courteous.
g. Get facts:
- Observe all alleged damage.
- Observe general conditions.
- Take notes, photographs, and document visit on blast
complaint form.
- Suggest seismograph placement on site.
h. Accept their opinions as valid concerns, not facts.
2. DON'T:
a. Argue or become angry.
b. Volunteer information.
c. Dispute claims of complaint.
d. Accept responsibility for causing alleged damage.
e. Agree to repairs.
f. Tell them no on their property.
g. Hesitate to seek additional support from seismologist or
explosives engineer.
h. Take abuse - politely leave.
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23
6900. Required I'epOrts: wilen and where to send
Type of Report When Where/Copies To
Blast report Immediately Plant manager
and District Office
Seismograph Report Explosive Engr. Dept.
(Form 1-21)
(Form 1-21)
NOTES
Blast Complaint
(Form 1-3)
Immediately Same as blast report.
Attach to blast report.
Explosives Theft
(phone Call)
Fed. Form
ATF F5400.5 (1-93)
Immediately
* URGENT
Plant manager
Production manager
Explosive Engr.
Dept. Local Law
Enforcement
*BATF 1-800-424-9555
Flyrock
(phone call)
Follow up with
written report
Immediately
*URGENT
Plant manager
Production manager
Explosive Engr. Dept.
(or V.P. Operations) or
Director of Procurement
Misfires either Immediately Plant manager
electric or nonelectric
(phone call) *URGENT Production manager
follow up with Explosive Engr. Dept.
written report (or Director of
Procurement or v.P.
Operations)
Vibrations (excess of Immediately Explosive Engr. Dept.
0.5 PPV or 127 db\) Production manager
(phone call)
Sleeping shots Immediately Explosive Engr. Dept.
(surface overnight) Production manager
(phone call)
24