Part VI. Explosives—Surface and Underground
4VAC25-40-780. Storage of explosive materials.
A. Detonators and explosives, other than blasting agents, shall be stored in magazines accepted by the Institute of Makers of Explosives or other approved agency.
B. Detonators shall not be stored in the same magazine with explosives.
C. Explosives magazines shall be:
1. Located in accordance with the American Table of Distances;
2. Detached structures located away from power lines, fuel storage areas, and other possible sources of fire;
3. Of substantial construction and constructed of noncombustible material or covered with fire-resistant material;
4. Reasonably bullet resistant;
5. Electrically bonded and grounded if constructed of metal;
6. Made of nonsparking material on the inside, including floors;
7. Provided with adequate and effectively screened ventilation openings near the floor and ceiling;
8. Kept locked securely when unattended;
9. Posted with suitable danger signs so located that a bullet passing through the sign will not strike the magazine;
10. Used exclusively for storage of explosives or detonators and blasting-related materials;
11. Kept clean and dry in the interior and in good repair;
12. Unheated, unless heated in a manner that does not create a fire or explosion hazard. Electrical heating devices shall not be used inside a magazine; and
13. Located at least 300 feet away from any underground mine opening, occupied building, public road, or private road not used in connection with the mine.
D. An accurate inventory log of explosives stored in the magazine shall be maintained on site.
E. Any theft or unaccounted loss of explosives shall be reported immediately by telephone to local police, state police, the U.S. Department of Justice, The Bureau of Alcohol, Tobacco, Firearms and Explosives and the Division of Mineral Mining.
F. Smoking or open flames shall be prohibited within 50 feet of explosives magazines or blasting agents storage facilities.
G. Areas surrounding magazines and facilities for the storage of blasting agents shall be kept clear of combustible materials, except live trees over 10 feet tall, for a distance of 50 feet in all directions.
H. Prior to repairs of a magazine which may cause a fire or explosion, the contents shall be removed to a safe location and guarded.
I. Explosives stored in magazines shall be:
1. Arranged so that the oldest stock is used first;
2. Separated by brand and type;
3. Stored with their top sides up; and
4. Stacked in a stable manner not over eight feet high.
J. When stored with other explosives, ammonium nitrate fuel oil blasting agents shall be physically separated to prevent contamination.
K. Damaged or deteriorated explosives and blasting agents shall be destroyed in a safe manner by a certified blaster.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.1, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998; Volume 25, Issue 20, eff. July 8, 2009.
4VAC25-40-790. Transportation.
A. Vehicles used to transport explosives shall be:
1. In good mechanical condition;
2. Posted with warning signs;
3. Provided with suitable fire extinguishers;
4. Provided with a nonsparking cargo area equipped with sides and tailgate;
5. Kept free of extraneous materials in the cargo area;
6. Operated at safe speeds over routes that expose the minimum number of personnel; and
7. Operated with the minimum number of persons required to safely transport the explosives.
B. Explosives and detonators shall be transported in separate vehicles unless they are separated by four inches of hardwood or the equivalent.
C. When explosives or detonators are transported by an electrically-powered vehicle, the cargo area shall be electrically insulated and covered.
D. Vehicles containing explosives shall not be left unattended or taken into a shop or building for any reason.
E. No person shall smoke while transporting explosives.
F. Explosives, detonators, or blasting agents shall not be transported on mantrips.
G. Explosives and detonators shall be transported in substantial, nonconductive, closed containers. Containers shall not be stacked higher than the sides or tailgate of the vehicle.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.2, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-800. Use of explosives.
A. A certified blaster shall be in direct charge of blasting activities.
B. Persons who assist in blasting activities shall be under the direct supervision of the certified blaster in charge and shall be alerted to the hazards involved.
C. Black powder or safety fuse shall not be used without approval from the director. Special approvals shall specify use restrictions and procedures necessary for safe storage, transportation, and use.
D. The design and loading of a blast shall provide sufficient burden, spacing, and stemming to prevent flyrock or other dangerous effects. Flyrock incidents shall be reported to the division immediately and details noted in the blast record.
E. Boreholes shall not be drilled where there is a danger of intersecting a loaded or misfired hole.
F. No person shall smoke or use an open flame within 50 feet of explosives or detonators.
G. Prior to bringing explosives and detonators to the blast site, the certified blaster in charge shall:
1. Monitor weather conditions to ensure safe loading and firing;
2. Inspect the blast site for hazards;
3. Inspect and clear the boreholes of obstructions; and
4. Remove personnel and equipment, except those used in loading the shot, from the blast site.
H. The certified blaster in charge shall review the drill logs to determine specific downhole conditions prior to loading the shot.
I. Boreholes to be blasted shall be loaded as near to the blasting time as practical. Loaded shots shall be blasted as soon as possible upon completion of loading and connection to the initiation device. Surface blasting shall be conducted during daylight hours only.
J. Explosives shall be kept a safe distance from detonators until they are made into a primer.
K. Primers shall not be made up or assembled in advance of the borehole being loaded.
L. Only wooden or other nonsparking implements shall be used to punch holes in an explosive cartridge.
M. Detonators shall be inserted completely and securely into explosive cartridges used as primers. Priming shall be sufficient to detonate the explosive column in the borehole.
N. Primers shall be inserted into the borehole slowly to prevent accidental detonation from impact, and tamping shall not be done directly on the primer.
O. Tamping poles shall be constructed of wood or nonsparking materials.
P. Unused explosives, detonators, and blasting agents shall be returned to the magazine or storage facility upon completion of loading activities and prior to firing the blast.
Q. Equipment and machinery used to load or stem boreholes shall not be operated over loaded boreholes for any reason. Areas containing loaded boreholes shall be guarded or barricaded and posted to prevent unauthorized entry.
R. Blast warning signals shall be established and posted at the mine. Audible warning signals shall be given prior to firing a blast and shall be loud enough to be heard within the entire blast area.
S. All personnel shall be removed from the blast area prior to connection to the initiation device and the firing of a blast.
T. Blasting personnel shall fire shots from a safe location.
U. A post-blast examination of the blast area shall be made by the certified blaster in charge. Other personnel shall not return to the blasting area until an all clear signal is received from the certified blaster in charge.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294, and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.3, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998; Volume 25, Issue 20, eff. July 8, 2009; Volume 35, Issue 4, eff. November 30, 2018.
4VAC25-40-810. Recordkeeping.
A detailed record of each surface blast shall be prepared immediately by the certified blaster. Records shall be maintained at the mine site for three years and subject to inspection by the division mine inspectors. Records shall contain the following information:
1. Name of company or contractor;
2. Location, date, and time of blast;
3. Name, signature, and certification number of the certified blaster in charge;
4. Type of material blasted;
5. Number of holes, and burden and spacing for each hole;
6. Drill logs of boreholes as required by 4VAC25-40-1095;
7. Types of explosives used;
8. Total amount of explosives used;
9. Maximum amount of explosives per delay period of eight milliseconds or greater;
10. Method of firing and type of circuit;
11. Direction and distance in feet to nearest dwelling house, public building, school, church, commercial or institutional building neither owned nor leased by the person conducting the blasting;
12. Weather conditions (including such factors as wind directions, etc.);
13. Height or length of stemming for each hole;
14. Whether mats or other protections were used;
15. Type of detonators used and timing of detonation for each detonator used;
16. The person taking the seismograph reading shall accurately indicate exact location of seismograph, if used, and shall also show the distance of seismograph from blast;
17. Seismograph records, including:
a. Name and signature of the person operating the seismograph;
b. Name of the person analyzing the seismograph record; and
c. Seismograph readings;
18. When a permanently installed seismograph is used to prove compliance, the record shall indicate the:
a. Name of the person and company that installed the seismograph; and
b. Name, signature, and company affiliation of the person validating the authenticity of the seismic data collected and transmitted by the permanent unit.
The information should be attached to the blast record as soon as it is available, but in no instance later than five working days after the shot; and
19. All anomalies or abnormalities occurring during the execution of the blast and actions taken to correct or address them.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294, and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.4, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998; Volume 25, Issue 20, eff. July 8, 2009; Volume 35, Issue 4, eff. November 30, 2018.
4VAC25-40-820. Procedure where a misfire occurs during a blast.
A. No person shall enter the blasting area for at least 15 minutes except in the case of safety fuse where special approvals apply.
B. Misfires shall be disposed of in a safe manner by the certified blaster.
C. The blast area shall be guarded or barricaded and posted with warning signs until the misfire has been cleared.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.5, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-830. When traffic to be stopped.
Prior to blasting near a mine haul road or public highway, traffic shall be stopped at a safe distance.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.6, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-840. Mudcapping.
Mudcapping in blasting operations shall be permitted only where the driller would be in a hazardous position in attempting to drill the rock or material to be blasted.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.7, eff. July 19, 1989.
4VAC25-40-850. Blasting near underground mines.
When conducting surface blasting activities near an underground mine, advance notice of blasting shall be given to the underground mine operator by the certified blaster.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.8, eff. July 19, 1989.
4VAC25-40-860. Blasting near pipelines or electrical lines.
When conducting surface blasting activities within 300 feet of private pipelines or electrical transmission lines, advance notice of blasting shall be given to the owners of the pipeline or transmission lines by the certified blaster.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.9, eff. July 19, 1989.
4VAC25-40-870. Streams and watercourses.
Surface blasting shall be prohibited if effects are liable to change the course or channel of any stream without a variance issued by the director.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.10, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-880. Ground vibration from blasting.
A. Ground vibration, measured as peak particle velocity resulting from blasting, shall not exceed the limits set forth in Figure 1 at any inhabited building not owned or leased by the operator, without approval of the director. A seismographic record shall be provided for each blast.
B. Seismic monitoring of each blast shall be conducted, unless the blast contains no more than 500 pounds of explosives and the scaled distance, Ds, is 90 feet or more, as calculated with the following scaled distance formulas:
Where:
W = Maximum charge weight of explosives in pounds per delay period of 8.0 milliseconds or more.
D = Distance in feet from the blast site to the nearest inhabited building not owned or leased by the mine operator.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294, and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.11, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998; Volume 25, Issue 20, eff. July 8, 2009; Volume 35, Issue 4, eff. November 30, 2018.
4VAC25-40-890. Air overpressure limits.
Air overpressure resulting from surface blasting shall not exceed 133 decibels, as measured with a 2Hz or lower flat response microphone, at any inhabited building not owned or leased by the operator.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.12, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998; Volume 25, Issue 20, eff. July 8, 2009.
4VAC25-40-893. Action plans.
Each operator shall maintain a plan to control the effects of blasting on areas adjacent to the operation. In the event of a blasting complaint, accident, or flyrock incident, the plan will be subject to review and approval of the division.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294, and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from Virginia Register Volume 25, Issue 20, eff. July 8, 2009; amended, Virginia Register Volume 35, Issue 4, eff. November 30, 2018.
4VAC25-40-895. Lower vibration and airblast levels.
If necessary to prevent damage, the director may specify lower allowable ground vibration and airblast levels than those provided by 4VAC25-40-880 and 4VAC25-40-890.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-900. (Repealed.)
Historical Notes
Derived from VR480-05-1.2 § 6.13, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998; repealed, Virginia Register Volume 29, Issue 25, eff. September 26, 2013.
4VAC25-40-910. Seismic testing and evaluation.
Seismic testing and evaluation to determine compliance with blasting regulations shall:
1. Utilize acceptable instrumentation that measures ground vibration, air overpressure, and vibration frequency;
2. Be conducted and analyzed by a qualified person; and
3. Be conducted whenever directed by the division.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294, and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.14, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998; Volume 35, Issue 4, eff. November 30, 2018.
4VAC25-40-920. Electric detonators.
A. When electric detonators are used, an acceptable blaster's galvanometer or blaster's multi-meter shall be used to test detonators, firing lines, series circuits, and total circuit resistance prior to firing.
B. Electric detonators of different brands shall not be used in the same blast.
C. Except when being tested with an acceptable instrument:
1. Electric detonators shall be kept shunted until they are connected into the series circuit;
2. Series circuits shall be kept shunted until they are connected onto the firing line; and
3. Firing lines shall be kept shunted until immediately before blasting.
D. Blasting machines or other acceptable power sources shall be suitable for the number of electric detonators to be fired and for the type of circuits to be used.
E. When electric detonators are used, sources of stray current to the blasting area shall be de-energized. Blasting activities shall be stopped immediately if stray current or static electricity in amounts sufficient to cause a premature detonation are encountered.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.15, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-925. Electronic detonators.
Electronic detonation systems shall be approved by the director as providing performance equivalent to that required in 4VAC25-40-920, and shall be used in accordance with the manufacturer's instructions.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from Virginia Register Volume 25, Issue 20, eff. July 8, 2009.
4VAC25-40-930. Nonelectric blasting.
A. When detonating cord manufactured with more than three grains per foot is used within 800 feet of inhabited buildings, not owned or leased by the operator, trunk lines shall be covered with at least six inches of loose earth or other acceptable material.
B. All detonating cord knots shall be tight and all connections kept at right angles to the trunk lines.
C. Detonators and delay connectors shall not be attached to exposed detonating cord by the certified blaster until the blast area is cleared.
D. Detonating cord blasting shall use a double trunk line or loop system to ensure complete detonation.
E. Detonating cord trunk lines, in multiple row blasts, shall make one or more complete loops, with crossties between loops at intervals not more than 200 feet.
F. When using a gas-charged initiation system, the certified blaster shall ensure that all components are fully charged prior to firing the blast. The blast area shall be cleared of personnel prior to charging the components.
G. Shock tube and other nonelectric detonation systems shall be used in accordance with manufacturers' recommendations.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 6.16, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-931. Blasting complaints.
In the event of a blasting complaint, accident, or flyrock investigation, all available data on the blast, including videos, shall be made available to the division.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294, and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from Virginia Register Volume 35, Issue 4, eff. November 30, 2018.
4VAC25-40-940. (Repealed.)
Historical Notes
Derived from VR480-05-1.2 § 7.1, eff. July 19, 1989; repealed, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-950. (Repealed.)
Historical Notes
Derived from VR480-05-1.2 § 7.2, eff. July 19, 1989; repealed, Virginia Register Volume 29, Issue 25, eff. September 26, 2013.
4VAC25-40-960. (Repealed.)
Historical Notes
Derived from VR480-05-1.2 § 7.3, eff. July 19, 1989; repealed, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-970. (Repealed.)
Historical Notes
Derived from VR480-05-1.2 § 7.4, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998; repealed, Virginia Register Volume 29, Issue 25, eff. September 26, 2013.