20210302_seis_spec_request

Parr, Adam
From: Parr, Adam
Sent: Tuesday, March 2, 2021 11:26 AM
To: Mike Mcgill
Cc: Bill Allgood; Todd Bouquin
Subject: RE: [External] Requested Blast records - 53-01 Lemon Springs
Mike,
I've reviewed the reports and will provide a letter stating that everything appears to be in compliance. However before
I do so, I'll need some additional information.
Blast 5 has Air overpressure reading of 132 dBL. Your permit specifies that you shall not exceed 129 decibels linear (dBL)
as measured at the immediate location of any regularly occupied building not owned or leased by the operator outside
of the permitted area such as a dwelling house, church, school, or public, commercial, or institutional building, unless an
alternate level based on the sensitivity of the seismograph microphone as specified below is being used:
Lower Frequency Limit of Measuring System (Hz)
Max Level (dBL)
0.1 Hz or lower -flat response
134 peak
2.0 Hz or lower -flat response
133 peak
6.0 Hz or lower -flat response
129 peak
The microphone specifications do not appear on the seismograph report. Will you have please have Deep Earth Logic
provide a statement/information on the microphone response? I need to verify that they are using a 2.0 Hz or lower —
flat response microphone to verify you are in compliance.
Thanks,
Adam Parr
Assistant State Mining Engineer
Division of Energy, Mineral and Land Resources
North Carolina Department of Environmental Quality
Office: [phone]
Cell: [phone]
FAX: [phone]
Email: [e-mail]
Physical Address: 512 N Salisbury Street
Mailing Address: 1612 Mail Service Center
Raleigh, North Carolina 27699-1612
Mining Program Website:
https://deg.nc.gov/mining-program

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From: Mike Mcgill <[e-mail]>
Sent: Wednesday, February 24, 20214:32 PM
To: Parr, Adam <[e-mail]>
Cc: Bill Allgood <[e-mail]>;
Subject: [External] Requested Blast records
Todd Bouquin <Todd.Bouquin@martin marietta.com>
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Adam,
Attached are the blast records you requested for our Lemon Springs quarry.
Please reach out if you have any questions or require any additional information.
Best regards,
Michael McGill
Director of Explosives Engineering
Martin Marietta
2710 Wycliff Road, Raleigh NC 27607-3033
t. [phone] c. [phone]
e. [e-mail]
www.martinmarietta.com
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