Oct 1, 2009 — Use blasting mats where flyrock damage is possible. containers, place them in a suitable nonmetallic container for manual.
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October 2009 24-1 Section 24 Blasting Operations This section discusses blasting operations, with specific focus on the following areas: General Requirements Radio and Electromagnetic Radiation Transporting Explosives Transporting Explosives Underground Storing Explosives Handling Explosives Loading Explosives and Blasting Agents Wiring operations Firing explosives Inspection following a blast Misfires Using safety fuses Using detonator cord Underwater blasting 24.1 General Requirements for Blasting Operations In addition to the requirements of th is section, the transportation, handling, storage, and use of explosives are subject to provisions of ANSI A10.7 – Safety Requirements for Transportation, Storag e, Handling, and Use of Commercial Explosives and Blasting Agents; 29 CFR 1910.109 – Explosives and Blasting Agents; 29 CFR 1926, Subpart U – Blasting and the Use of Explosives (1926.900 to 1926.914); and 27 CFR Part 55 – Commerce in Explosives. 24.1.1 Competent Supervision. A blasting supervisor must be designated to direct and supervise all blasting operations. This includes the transportation, handling, storage, and use of explosives and blasting agents. The supervisor must provide written records of past experience to the employer as evidence of competency. 24.1.2 Qualifications. a. Personnel. Employees who transport, stor e, handle, or use explosives or blasting agents must be at least 21 y ears of age. They must be able to give and understand written and verbal instructions.
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Reclamation Safety and Health Standards 24-2 October 2009 b. Blasters. Blasters must be qualified through training, knowledge, and experience in transporting, storing, handling, and using explosives, and have a working knowledge of State and local laws and regulations which pertain to explosives. Blasters must hold a Federal, State, or local license or certificate, have proof of formal training attended within the last 5 years, or three recommendations fr om past employers or explosives manufacturers testifying to the blaste r™s knowledge and ability to perform in a safe manner the type of blasting that will be required. 24.1.3 Blasting Plan. Submit a comprehensive blasti ng plan before the start of blasting operations and have it approved. The blasting plan may be submitted as part of the overall site safety plan, as required by the “Contractor Requirements” section of these standards (for contract operations) or as a supplementary plan to a Job Hazard Analysis. Explosives must not be transported onto the jobsite before the plan has been approved. The plan must identify proposed methods and procedures for conforming with referenced standards and regulations, and it must include the following information: Method and equipment for transpor ting explosives and detonators Type and location of storage facilities Type and quantity of explosives and detonators Primer assembly procedure and location Employee training programs Provisions for protecting people, structures, and private and public property Provisions for developing and di stributing a daily blasting plan covering hole diameter, spacing, loading, and delay patterns Provisions for disposal of explosiv es, blasting agents, and associated materials 24.1.4 Security and Inventory. Secure and protect explosives from theft. Maintain an accurate running inventory of all explosives stored at the jobsite. Such records must be available. Pr omptly report any loss or theft to the appropriate authorities. 24.1.5 Notifications. Notify the owners and operators of the facility and take all necessary precautions for the safe cont rol of the blasting operations before beginning blasting operations in the immediate vicinity of buildings, public roads, overhead powerlines, utility services, or similar facilities. At least 24 hours before blasting in the vicinity of gas, electric, water, communications, or other utilities is to begin, the blasting supervisor must notify appropriate utility representatives.
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Section 24ŠBlasting Operations October 2009 24-3 24.1.6 Smoking Restrictions. Prohibit smoking, firearms, matches, open flame lamps, fire, heat-producing devices, and spar ks in or near explosive storage sites or in areas where explosives ar e handled, transported, or used. 24.1.7 Thunderstorms. Discontinue the handling or use of explosives during the approach and progress of a thunderstorm. All employees must leave the danger areas and seek a place of safety when these conditions are present. Install an approved lightning warning device capable of detecting atmospheric conditions that could produce lightning on the jobsite. Warning devices must be acceptable to the COR or office head before installation. 24.1.8 Damage Control. Take precautions to minimize ground vibration, airblast, and flyrock. Include a damage c ontrol section in the site blasting plan that addresses these issues. Use blasting mats where flyrock damage is possible. Use modern blasting seismographs and me thods to measure ground vibrations and air blast levels at designated structures or locations. Unless otherwise specified, control the blasting so that ground vibrations and airblast levels do not exceed the following: Ground Vibration Limits 1 Type of Structure 2 Peak Particle Velocity (inches per second) At Low Frequency 3 (<40 Hertz) At High Frequency (>40 Hertz) Modern homes, drywall interiors 0.75 2.0 Older homes, plaster on wood lath construction for interior walls 0.5 2.0 Reference: Siskind, D.E., M.S. Stagg, J.W. K opp, and C.H. Dowding, ﬁStructure Response and Damage Produced by Ground Vibration from Surf ace Mine Blasting.ﬂ U.S. Department of the Interior, Bureau of Mines, Report of Investigations RI 8507, 1980. 1The graph in Appendix B of the above reference ma y be used in lieu of the limits listed in this table. 2For precarious structures not listed in the tabl e, use the limits for older homes; for all other structures not listed in the table, use the limits listed for modern homes. 3All spectral peaks within 50 percent amplitude of the predominant frequency must be analyzed. Airblast Limits Instrumentation Air Blast (decibels) 0.1 hertz high-pass system 134 2 hertz high-pass system 133 5 or 6 hertz high-pass system 129 C-slow (for events not exceeding 2 seconds™ duration) 105 Reference: Siskind, D.E., V.J. Stachura, M. S. Stagg, and J.W. Kopp, ﬁStructure Response and Damage Produced by Airblast from Surface Mining, ﬂ U.S. Department of the Interior, Bureau of Mines, Report of Investigations RI 8485, 1980.
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Reclamation Safety and Health Standards 24-4 October 2009 24.1.9 Warning Signs. Post warning signs at access points to blasting areas. 24.1.10 Destruction of Explosives. Deteriorated or damaged explosives, blasting agents, blasting supplies are prohibited. Destroy and remove these and all excess explosives from the site in accordance with the specific written instructions of the manufacturer. 24.1.11 Empty Explosive Containers. Destroy empty boxes and combustible packing materials which have contained explosives in accordance with the manufacturer™s disposal procedures. If disposal is through burning, all personnel must remain at least 100 feet from the burning site once the material has been ignited and until no visible flames or sm oke have been detected for 1 hour. 24.1.12 Fire. If a fire begins that involves explosives, or where the danger of the fire contacting explosives is imminent, do not fight the fire. All personnel must seek safe shelter; guard the fire area to prevent intruders. 24.2 Radio and Electromagnetic Radiation Take adequate precautions to prevent acc idental discharge of electric blasting caps from current induced by radar, radi o transmitters, powerlines, and similar sources of electromagnetic radiation. 24.2.1 Mobile Radio Transmitters. Mobile radio transmitters or cellular telephones within 100 feet of electric blasting caps or delays not in their original containers are prohibited unless de-energized and effectively locked. Post warning signs at least 36 by 42 inches in size, stating BLASTING ZONEŠTURN OFF 2-WAY RADIOS AND C ELLULAR TELEPHONES, on all public roads within 1,000 feet of blasting operations, using electronic detonators. 24.2.2 Non-electric Firing Systems. If it is not possible to observe the safe clearance distances from radio frequency (RF) transmitter stations, as set forth in Institute of Makers of Explosives (IME) publication 20, “Safety Guide for the Prevention of Radio Frequency Radiation Hazards in the Use Of Electric Blasting Caps,” use nonelectric firing systems to bl ast. Electrical detonators must not be stored or used within the IME-specif ied distances of a transmitter station. 24.3 Requirements for Transporting Explosives Transporting explosives by air, water, or on public highways must comply with the provisions of US Department of Transportation Regulations contained in 46 CFR 146-149 – Water Carriers; 49 CFR 171-177 Subchapter C – Hazardous Materials Transportation; and 49 CFR 390-397, “Motor Carriers.” 24.3.1 Vehicles. Vehicles used to transport explosives must conform to the following requirements:
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Section 24ŠBlasting Operations October 2009 24-5 a. They must be in good repair, wi th all electrical wiring completely protected and securely fastened to prevent short circuits. b. They must have tight floors. C over any exposed spark-producing metal with wood or other nonsparking mate rial to prevent contact with containers of explosives. c. Do not load them beyond rated cap acity, and secure the explosives to prevent shifting or dislodgment. d. Transport explosive materials in open-bodied motor vehicles only if they have been loaded into a portable ma gazine that is securely fastened to the truck bed. Never transport explosive materials in open-bodied motor vehicles that depend on a fire-resistant tarpaulin cover for protection. e. Mark vehicles transporting explosives with reflectorized signs on both sides and the front and rear with “EXPLOSIVES” in red letters. Make letters at least 4 inches high on a white background or placarded in accordance with 49 CFR Part 172, Subpart F – “Placarding.” f. Equip them with two or more fire extinguishers with a rating of at least 2-A:40-B:C. g. Inspect them daily before use to ensure that the vehicle is in proper condition for safe transportation. The inspection must determine that fire extinguishers are charged and ready; electric wiring is protected and fastened to prevent short circuiting; chassis, motor, pan, and underbody are reasonably clean and free of oil and grease; fuel tanks and lines are secure and have no leaks; tires are in serviceable condition with proper inflation; and lights, brakes, horns, wipers, etc., are functioning properly. 24.3.2 Vehicle Operators. Motor vehicle operators transporting explosives must be at least 21 years old and be properly licensed drivers. Drivers must be physically fit, careful, capable, and reliable. Drivers must not be unlawful users of, or addicted to, alcohol, narcotics, or dangerous drugs. Drivers must be familiar with applicable local, State, a nd Federal laws and regulations governing the transportation of explosive materials. Transportation on Federal highways or other public roads requires a commercial driver’s license. 24.3.3 Caps and Detonators. Do not transport blasting caps and detonators with other explosives unless the blasting caps or detonators are in a closed metal storage container that has at least a 2-inch wood lining. Such containers must be at least 2 feet away from other explosives. 24.3.4 Flammable Materials. Do not transport spark-producing tools, carbides, oil, matches, firearms, acids, storage ba tteries, oxidizing or corrosive compounds, or flammable materials with explosives.
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Reclamation Safety and Health Standards 24-6 October 2009 24.3.5 Parking. Attend vehicles containing explosives at all times. Do not park loaded vehicles, even if attended, near any bridge, tunnel, or other structure that may be occupied or locations wher e people may congregate or assemble. 24.3.6 Fueling. Do not refuel vehicles while they are carry ing explosives. 24.3.7 Smoking Restrictions. Employees who transport, handle, or use explosives must not smoke or carry on their persons or in the vehicle matches, lighters, firearms, ammunition, or flame- producing devices of any description. 24.3.8 Riders. Permit only the authorized driver and helper to ride on trucks transporting explosives or detonators. 24.4 Requirements for Transporting Explosives Underground In addition to the requirements set forth in the previous subsection, “Requirements for Transporting Explosives ,” the provisions of this subsection apply to underground transportation of explosives. 24.4.1 Hoists. Notify the hoist operator before transporting explosives or blasting agents in a shaft conveyance. Do not permit any person to ride a hoist or shaft conveyance transporting explosives or blasting agents. Do not transport detonators while tran sporting explosives. 24.4.2 Powder Cars and Trucks. Convey explosives and blasting agents only in specifically built or equipped insulated powder cars or truck-mounted containers approved by the State entity having jurisdiction. Mark powder cars with reflectorized signs on both ends and sides with “EXPLOSIVES” in letters at least 4 inches high against a sharply contrasting background at all times that there are explosives in the car. Cover or re move the signs when no explosives are present. Do not transport explosives or blasting agents on a locomotive; at least two car lengths must separate the locomo tive from the powder car. Pull (do not push) powder cars. 24.4.3 Common Transport of Detonators and Explosive Materials. Physically separate compartments for tr ansporting both detonators and explosive materials in the same conveyance or car by at least 24 inches or by a solid partition at least 6 inches th ick. Do not transport detonators and other explosive materials together in any shaft-conveyance. 24.4.4 Transportation of Personnel and Explosives. No personnel, other than the transport operator, helper, and the individuals handling the explosives may ride transports carrying explosives. 24.4.5 Truck Transportation. Trucks transporting explosives underground must meet other applicable provisions of these standards and have their electrical systems checked weekly to detect possible el ectrical hazards. A written record of
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Reclamation Safety and Health Standards 24-8 October 2009 24.5.7 Posting. Post areas around magazines with “EXPLOSIVES” signs. Place the signs so that a bullet passing through the sign will not strike a magazine. 24.5.8 Storage. Store explosives in their original containers. Store containers of explosives with the top side up as designated on the container. Use the oldest stock of explosives first. 24.5.9 Maintenance. Promptly remove debris and combustible material from magazines. When magazine floors become stained with explosives, clean them in accordance with the explosive manufacturer™s instructions. 24.5.10 Transfer In and Out. Provide for the safe transfer of explosives in and out of magazines, includ ing providing ramps or walkways, as necessary. 24.5.11 Storage Underground. Do not permanently store explosives underground. Temporary storage must comp ly with the following requirements: a. Powder Cars. Restrict temporary storage to limited supplies stored in specially designed powder cars located at least 1,000 feet from the face or blasting area. Do not permit transforme rs, storage of flammable materials, welding, open flame, smoking, and othe r ignition sources within 100 feet of the powder car. b. Posting and Lighting. Designate the storage area or siding by a red light visible in all directions, and post both ends of the powder car with a luminous sign, stating “EXPLOSI VES – NO SMOKING, FLAME, OR WELDING WITHIN 100 FEET.” c. Protection. Locate or barricade the powde r car to protect it from damage. Design siding or car-passes, wh en used for temporary storage, to protect the powder car from accidental entry by other cars and to prevent accidental entry of the powder car to the main line. The protective devices installed are subject to approval of both the employe r and the State entity having jurisdiction. 24.6 Requirements for Handling Explosives 24.6.1 Handling Explosives. Handle explosives carefully. Do not drop, throw, or slide them. Carry detonators, primer s, and other explosives in separate containers when transporting them manually. When they are not in their original containers, place them in a suitable nonmetallic container for manual transportation. 24.6.2 Removal from Containers. Remove explosives from their original containers only as needed for immediate use. Use only nonsparking tools or devices to open such containers. Dispose of empty containers and packing in accordance with the manufacturer’s recomm endations, or promptly burn them in an approved location.
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Section 24ŠBlasting Operations October 2009 24-9 24.7 Loading Explosives and Blasting Agents 24.7.1 Planning. Plan and schedule excavation so that drilling and loading operations will not conflict. Do not perm it loading within 50 feet of drilling operations. Do not permit any activity, other than that which is required for loading holes, within 50 feet of loaded holes or holes that have the explosives in place, ready to load. A qualified blas ter must supervise loading operations. 24.7.2 Drilling. Do not drill in an area already blasted until examining remaining “bootlegs” (holes that do not detonate full depth) for unexploded charges, as well as the total area, to ma ke sure no unexploded charges remain. Do not insert drills, picks, or bars into bootlegs, even if examination fails to disclose explosives. 24.7.3 Loading Areas. Make boreholes ready for loading, and remove equipment and tools not used for loadi ng from the area before delivering the explosives to the site. Isolate the loading areas with appropriate signs or temporary barricades to prohibit access by unauthorized people. While the bare holes are being loaded with explosives, exclude all personnel, other than those involved in the loading of boreholes, from the blast site. 24.7.4 Boreholes. Make boreholes large enough to permit loading of cartridges and explosives without forcing. Prime, load, tamp, and fire as promptly as possible with a minimum of exposure to personnel. 24.7.5 Tamping. Tamp only with wooden or plastic tamping poles without exposed metal parts. Nonsparking metal connectors on jointed poles are permissible. Seat cartridges by even, steady pressure, and do not tamp primers. 24.7.6 Priming. Follow the manufacturer’s recommendations in priming cartridges. Make primers up only at the loading area and in quantities limited to the number required for a single round of blasting. 24.7.7 Stemming. Stem all blastholes in open work with noncombustible material to the collar or to a poi nt that will confine the charge. 24.7.8 Extraneous Electricity. Prohibit electric conductors, electric equipment, and all sources of ignition in or adjacent to the loading area. Remove lights 50 feet from the face before starting to load in tunnels and shafts. If stray currents are suspected, thoroughly check out the area with suitable instruments. If stray currents cannot be eliminated, use nonele ctrical detonators, delays, and caps. 24.7.9 Shunts. Do not remove the manufacturer’s shunt from the cap leg wires until you complete loading and connect th e cap into the blasting circuit. 24.7.10 Sprung Holes. Do not chamber (spring) boreholes.
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Reclamation Safety and Health Standards 24-10 October 2009 24.7.11 Blasting Mats. Where blasting may expose personnel or property to injury or damage from flying material, cover the charges with blasting mats. Carefully protect the blasting circuits, and do not permit the circuits to contact steel mats. 24.7.12 Loading and Shooting. Do not leave loaded holes unattended or unprotected. If possible, fire all holes loaded on a shift during that same shift. If it is necessary to delay firing because of an emergency, isolate the area and post watchpersons to prevent entry to the area. Conduct aboveground blasting operations between sunup and sundown. 24.7.13 Pneumatic Loading Systems. Conduct the hazards from static electricity and stray currents associated with pneumatically loading boreholes with blasting agents, take the following precautions: a. Use only approved pneumatic loaders. b. Effectively ground and bond the entire system, including placers, valves, and loading hose. Ground at the face in tunnels and shafts. Do not use piping and rails to ground the system. c. Following installation of the ground, check the ground with an approved meter to ensure that the resistance is within safe limits. d. Use loading hoses of an approved, nonsparking, semiconductive material designed to maintain static electricity within safe limits. 24.7.14 Underground Use of Blasting Agents. Before using blasting agents underground, a powder technician representing the explosive manufacturer or supplier must inspect the proposed method of loading and the loading equipment. Submit written evidence of such insp ection and approval of the systems. 24.8 Wiring Operations 24.8.1 Firing Devices. Use an electric blasting machine to fire blasts using electronic detonators. Do not fire blasts by connection to any other electrical system. Fire blasts using nonelectric detonators with a blasting machine or starting device prescribed by the detonator manufacturer. Do not use cap and fuse firing underground or in the excavation of shafts. Do not use electric blasting caps within 500 feet of energized high-voltage lines or facilities. 24.8.2 Wiring Procedure. Do not remove the manufacturer’s shunt from the cap leg wires until the cap has been connected to the leadlines or to another cap in preparation for the assembly of two or more caps into a single series. When firing two or more series of caps as a series-p arallel system, make sure that the caps in each series are the same in number (qua ntity, not delay periods), and test each series separately with an approved blasting galvanometer to: (1) ensure that the
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Section 24ŠBlasting Operations October 2009 24-11 series is complete, and (2) ensure that each series has the same resistance and that the resistance is close to the calculated resistance for the series. If the first reading indicates an incomplete circuit, locate the fault and correct it. If the second reading indicates a higher or lower resistance than calculated, correct the situation before final hookup and firing. 24.8.3 Electric Caps and Delays. All caps and delays in a shot must be made by the same manufacturer, and the number in a circuit must not exceed the capacity of the blasting machin e or power source. 24.8.4 Galvanometer Testing. Make the following tests with an approved blasting galvanometer during all wiring operations: (1) Test the circuit, including all caps, before connecting it to the firing line. (2) Check the firing line before connecting it to the blasting machine or power source. 24.8.5 Firing Lines. Firing lines must be of sufficient current-carrying capacity but not smaller than No. 14 gauge solid copper wire or equivalent. Do not connect the firing line to the blasting machine or power source until you have completed and tested the wiring and clea red the blast area. Do not ground a power circuit used for firing electric blasting caps. 24.8.6 Connecting and Lead Wires. Connecting and lead wires must be insulated single solid wires of su fficient current-carrying capacity. 24.8.7 Power Circuit. When using a power circuit for firing, lock the firing switch in the “OFF” (open) position at all times, except when firing. Design the power circuit so that the firing lines to the cap circuit are automatically short- circuited when the switch is in the “OFF” position. Entrust the keys to the firing switch only to the blaster. In underground operations, the firing circuit must have a “lightning” gap of at least 5 feet, located between the firing switch and the source of power. Bridge the gap with a flexible jumper cord just before firing the blast. 24.9 Firing 24.9.1 Preparation. Before connecting the firing line to the power source, notify all personnel in the danger area of the blast and remove them to a safe area. Make satisfactory arrangements for evacuating the danger area and ensuring that no one enters the area before the blast. 24.9.2 Responsibility. The blaster must be in charge of the blasting machine or firing switch, and must connect the firing line to the firing device. The blaster must make all connections from the cap ci rcuit back to the firing device, and the firing line must remain shorted until c onnected to the firing device immediately before firing.
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