20240418_ADI_Received

April 16, 2024
Mr.Adam Parr
Division of Energy, Mineral and Land Resources
Department of Environmental Quality
1612 Mail Service Center
Raleigh, NC 27699-1612
RE: Rockingham Quarry
Mining Permit No. 77-01
Richmond County
Yadkin-PeeDee River Basin
Attached you will find a file, with an appendix, providing Vulcan Materials'response to comments received from
the DEQ on April 8th. Any information detailing the presence of muck during a blast and the chain of approval
permitting that blast can be found on our VMC Form 4901 "Driller's Log and Shot Layout Report". These forms
could be made available upon request. Please feel free to contact me with any questions and let me know if
there is anything else we can provide related to this matter.
Thank you for your assistance.
Respectfully,
Ryan Manley
Drilling&Blasting Manager
Vulcan Construction Materials, LLC
Northeast&East Division
(980)-214-3472 RECEIVED
[e-mail]
APR 18 ?01
LAND QUAL17-V
9V"Y"Ye PROGRAM
1

I am reaching out on behalf of Vulcan Materials Rockingham Quarry. After thorough examination of our
current mine permit,we have noticed a blasting subset(M)that we would like to request to modify or
remove from the permit.
M "Unless it is impractical from a standpoint of safety,all shots shall be completely mucked prior to
the detonation of adjacent blasts to ensure that the actual burden conditions can be determined for
explosive loading conditions"
For many years this did not affect our ability to safely operate while meeting market demands. At this
point of the mine's life,shooting into a muckpile has become a technique that could benefit current pit
development as well as become vital to meet market demands in the future. This has come to light due
to our recent commencement of mining in pit 2 along with current access to necessary reserves in pit 1.
This language was added due to an issue with a flyrock incident many years ago. At that time blasting
was being done by a contract explosives company. Since that incident,there have been several changes
to the operation that will limit flyrock impacts. These changes include:
• An internal blasting program was created with updated drilling and blasting standards. Any contract
drilling and blasting that occurs on site are held to these internal standards as well.
• All muck bound shots require further approval from Area Manager/Drilling and Blasting Manager before
loading.
• Traffic on Galestown Road is stopped during blasting operations.
• VMC has purchased additional property on the opposite side of Galestown Road.
• The depth of the pit has increased in pit 1 and the blasting occurring in pit 2 is at a greater distance to
Galestown Road than the blast where flyrock originated from.
• Electronic detonators are utilized when necessary,allowing for greater control of muckpile heave. This
allows us to create more relief within the timing schematic of the shot to account for any extra
confinement.
• 2D profiling systems and even 3D profiling systems are available to our blasting engineers and all shots
are required to have burden checked before loading.
• The design of the shot patterns,detonation timing,and explosive loads are customized to the site
conditions and include consideration of the muck pile against a working face.
Vulcan Materials will implement the following additional measures,on any blast that is not completely
mucked out before detonation,to help further mitigate the possibility of a flyrock.
1. The minimum face hole burden will be increased from 2 times the borehole diameter to 3 times the
borehole diameter throughout muck bound areas of the face. Any solid areas,above the muckpile,will
have their minimum burdens increased to 2.5 times the borehole diameter to ensure proper energy
confinement.
2. Face burden(including muck)will be measured with 2D profiling. If there are areas of the face that
cannot be measured with 2D profiling,a 3D profiling system will be used. Face burden measurements will
not be made using a burden pole.
3. All blasts will be loaded with electronic detonators and timed in such a way that there is at least 10ms per
1 ft of burden within inter-row timing designs.
4. Even if abundant burden is present due to muck,all seams on face holes will be decked through to ensure
proper containment of explosive energy.
5. The minimum stemming depth required will be increased by 25%and will not be less than 70%of the
blast pattern's designed burden.
6. The blast area will be increased to a minimum of 2,000'in the direction of any muck-bound face and
1,000'in all other directions.
We feel the blasting can be done in a safe and controlled manner. If a permit modification is possible,
I'd be happy to discuss with you further how Vulcan requires our blasting to be performed when
working with a muck bound face. Please feel free to reach out at your convenience.
1
1

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Figure 1: Blast with muck pile where 2Dprofiling • • NOT be sufficient
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Figure 2: Side view of power trough that would need to be 3D profiled before detonation to ensure
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proper burden

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Figure 3: Blast where 2D
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profiling WOULD •• sufficient
Figure 4: Side view of muck pile showingblast that 2D profiling could •' used to safely determine

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Figure 5: Rockingham new blast area example if red line was muck bound face.
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Figure 6: 1000' Radius portion of new blast area on theoretical muck bound blast

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Figure 7: New blast area for theoretical muck bound blast showing 1000' radius and 2000' added blast
area in front of muck bound face

I am reaching out on behalf of Vulcan Materials Rockingham Quarry. After thorough examination of our
current mine permit,we have noticed a blasting subset(M)that we would like to request to modify or
remove from the permit.
M "Unless it is impractical from a standpoint of safety,all shots shall be completely mucked prior to
the detonation of adjacent blasts to ensure that the actual burden conditions can be determined for
explosive loading conditions"
For many years this did not affect our ability to safely operate while meeting market demands. At this
point of the mine's life,shooting into a muckpile has become a technique that could benefit current pit
development as well as become vital to meet market demands in the future. This has come to light due
to our recent commencement of mining in pit 2 along with current access to necessary reserves in pit 1.
This language was added due to an issue with a flyrock incident many years ago. At that time blasting
was being done by a contract explosives company. Since that incident,there have been several changes
to the operation that will limit flyrock impacts. These changes include:
An internal blasting program was created with updated drilling and blasting standards. Any contract
drilling and blasting that occurs on site are held to these internal standards as well.
• All muck bound shots require further approval from Area Manager/Drilling and Blasting Manager before
loading.
• Traffic on Galestown Road is stopped during blasting operations.
• VMC has purchased additional property on the opposite side of Galestown Road.
• The depth of the pit has increased in pit 1 and the blasting occurring in pit 2 is at a greater distance to
Galestown Road than the blast where flyrock originated from.
• Electronic detonators are utilized when necessary,allowing for greater control of muckpile heave. This
allows us to create more relief within the timing schematic of the shot to account for any extra
confinement.
• 2D profiling systems and even 3D profiling systems are available to our blasting engineers and all shots
are required to have burden checked before loading.
• The design of the shot patterns,detonation timing,and explosive loads are customized to the site
conditions and include consideration of the muck pile against a working face.
Vulcan Materials will implement the following additional measures,on any blast that is not completely
mucked out before detonation,to help further mitigate the possibility of a flyrock.
1. The minimum face hole burden will be increased from 2 times the borehole diameter to 3 times the
borehole diameter throughout muck bound areas of the face. Any solid areas,above the muckpile,will
have their minimum burdens increased to 2.5 times the borehole diameter to ensure proper energy
confinement.
2. Face burden(including muck)will be measured with 2D profiling. If there are areas of the face that
cannot be measured with 2D profiling,a 3D profiling system will be used. Face burden measurements will
not be made using a burden pole.
3. All blasts will be loaded with electronic detonators and timed in such a way that there is at least 10ms per
1 ft of burden within inter-row timing designs.
4. Even if abundant burden is present due to muck,all seams on face holes will be decked through to ensure
proper containment of explosive energy.
S. The minimum stemming depth required will be increased by 25%and will not be less than 70%of the
blast pattern's designed burden.
6. The blast area will be increased to a minimum of 2,000'in the direction of any muck-bound face and
1,000'in all other directions.
We feel the blasting can be done in a safe and controlled manner. If a permit modification is possible,
I'd be happy to discuss with you further how Vulcan requires our blasting to be performed when
working with amuck bound face. Please feel free to reach out at your convenience.

APPENDIX:
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Figure 1: Blast with muck pile where 2D profiling would NOT be sufficient
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Figure 2: Side view of power trough that would need to be 31) profiled before detonation to ensure
proper burden

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Figure 3: Blast where 2D profiling WOULD be sufficient
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Figure 4: Side view of muck pile showing a blast that 2D profiling could be used to safely determine
burdens

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Figure 5: Rockingham new blast area example if red line was muck bound face.
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Figure 6: 1000' Radius portion of new blast area on theoretical muck bound blast

w.�{.91.11nd'•` 'lye . ''h�..�. .e' 1 <
Figure T New blast area for theoretical muck bound blast showing 1000' radius and 2000' added blast
area in front of muck bound face