20211206_13_Blast_Study

August 9, 2021
Mr. James Schad
YOUR EQUIPMENT GUYS
LANDVESTORS GROUP
1109 E Ozark Avenue
Gastonia, NC 28054
RE: Predicted Ground Vibration and Air Overpressure
Proposed New London, NC Location
Dear Mr. Schad:
VibraTech
VibraTechinc.com
377 Rubin Center Drive
Suite 114
Fort Mill, SC 29708
Phone [phone]
Fax [phone]
Per your request, Vibra-Tech, Inc. offers the following vibration and air overpressure predictions
based on historical loading information provided by Austin Powder Company.
Aerial photogrammetry indicates the closest non -company owned structure to the permitted
excavation boundary at the New London site will be approximately 575 feet. You have indicated
that typical production blast designs will include a 5.5-inch diameter borehole drilled to a depth
of 50 feet. Decking with an inert stemming deck dividing the hole into two sections may be
utilized to control vibration and air overpressure. The explosive material produced by Austin
Powder Company with an average product density of 1.18 g/cm3. given these parameters, it is
expected that a maximum pounds per delay detonated would be approximately 196 lbs for a
decked column.
Methods:
The International Society of Explosives Engineers Blaster's Handbook, 18t" Edition provides
Equations 1- 3 below that predict the peak particle velocity of a blast given the distance from
the blast in question and the amount of explosives detonated per 8ms delay. Equation 2
represents a general industry prediction, whereas Equation 3 represents a more confined
detonation:
Scaled Distance = Distance
max. lbs. per delay
[1]
1.6
Peak Particle Velocity = 160 x I Distance 1- [2]
\ max. lbs. per delay)
Distance 1.6
Peak Particle Velocity = 242 x G max. lbs. per delay) [31

VibraTech
The ISEE Blaster's handbook, 181" Edition also provides Equations 4 - 8 below as methods to
predict peak air overpressure of a blast given the distance to the blast in question and the
amount of explosives detonated per 8ms delay. Equation 5 represents air overpressure from a
typical construction blast. Equation 6 represents air overpressure from a typical quarry face.
Equation 7 represents air overpressure from a typical coal mine highwall.:
Cubed Root Scaled Distance = distance [4]
3 lbs
delay
PeakAir Overpressure (psi) = I* (CRSD)-1.1 [5]
Peak Air Overpressure (psi) = 1.32 * (CRSD)-0.97 [6]
Peak Air Overpressure (psi) = 0.162 * (CRSD)-0.79 [7]
Convertpsi to dB(L) = 20 *log log psi [8]
0.0000000029
Given Parameters:
Proposed Typical Production Blast Hole Diameter — 5.5 in
Proposed Typical Production Blast Hole Depth — 50 ft
Proposed Typical Production Blast Explosive Product Density — 73.67 Ibs/ft3

VibraTech
The following are the predicted values for the New London location, using these equations and
initial loading information provided by your group:
Peak Particle Velocity 5.5" hole (Decked):
Distance from Blast
(ft)
Scaled Distance
Calculated Peak
Particle Velocity
Equation 2
(in/sec)
Calculated Peak
Particle Velocity
Equation 3
(in/sec)
575
41.1
0.418
0.633
700
50.1
0.305
0.462
750
53.6
0.273
0.414
800
57.2
0.247
0.373
1000
71.5
0.173
0.261
1200
85.8
0.129
0.195
1500
107.3
0.090
0.136
2000
143.1
0.057
0.086
2500
178.8
0.040
0.060
3000
214.6
0.030
0.045
Peak Air Overpressure 5.5" hole (Decked):
Distance from
Blast (ft)
Cubed Root
Scaled
Distance
Calculated Peak Air
Overpressure
Equation 5 (dBL)
Calculated Peak Air
Overpressure
Equation 6 (dBL)
Calculated Peak Air
Overpressure
Equation 7 (dBL)
575
99.1
126.8
134.4
123.4
700
120.6
125.0
132.8
122.1
750
129.2
124.3
132.2
121.6
800
137.8
123.7
131.7
121.1
1000
172.3
121.6
129.8
119.6
1200
206.8
119.8
128.2
118.4
1500
258.5
117.7
126.4
116.8
2000
344.6
114.9
123.9
114.9
2500
430.8
112.8
122.1
113.3
3000
516.9
111.1
120.5
112.1

/// VibraTech
All blasts will be monitored using at least one seismic monitoring station that will be located at
or adjacent to the closest non -company owned structure to each blast. The results from the
seismic testing will be used to determine future blast designs to remain in compliance with all
applicable North Carolina Department of Environmental Quality (DEQ) regulations for ground
vibration and air overpressure. These adjustments are made on a shot -by -shot basis in virtually
every quarry facility across the country and will be implemented at the New London, NC site in
accordance with industry best practices.
If you have any questions regarding this matter, please do not hesitate to contact our office.
Respectfully submitted,
VIBRA-TECH, INC.
Gs�
Andrew Coil
Area Manager, SC
Chuck Jaworski
Regional Accounts Manager SE
Vibra-Tech, Inc., shall not be liable for any claims of tangible property damage where such damage is not
solely, directly, and physically caused by Vibra-Tech, Inc. Additionally, Vibra-Tech, Inc., shall not be liable, in
whole or in part, for any claims of tangible property damage brought by or on behalf of third -party
claimants.