Appendix R- Blast Impact Study - 09-04-2024

•*> AUSTIN POWDER
Luke Provencher, Director of Technical Services
Austin Powder Company—US&Canada
September 4, 2024
To: John Khun, Ryan McCluskey, David Thompson, Sam Saltman
Cc: Stuart Brashear, Tom Cochran Jr
4250 Congress Streer, Suite 900
Charlotte, NC 28209
Albemarle Kings Mountain Mine — Blasting Impact Study
Community Impact Summary
Austin Powder was asked to conduct a blasting impact study for the proposed Albemarle Kings Mountain Mine
(Albemarle Mine) in Cleveland County, North Carolina. This study summarizes a review of the possible impacts
from blasting operations on the surrounding communities. Multiple simulations were run using Austin Powder's
proprietary blast modelling software (Paradigm)to validate the potential impacts of ground vibrations, air
overpressure, and flyrock. All three potential impact categories were simulated based on the assumed blasting
parameters coupled with the best information available at the time of this study. This study was conducted to
identify those circumstances and considerations necessary to ensure blasting operations can be conducted safely
with minimal impact to the surrounding communities and in compliance with NC State blasting regulations.
Project Overview and Community Proximity
Figure 1 depicts an overview of the pit boundary and mine property boundary along with 6 highlighted occupied
properties which have been identified as some of the vibration and overpressure monitoring areas of interest(AOI)
for this study. These AOIs are based on current property ownership and could be subject to change in the future.
All blasting activities will take place within the identified pit boundary which has defined the minimum and maximum
distances to the property boundary and AOIs during blasting. Also of note is the mine's proximity to a neighboring
quarry directly to the east. This is not expected to require additional vibration or overpressure monitoring at this
stage but has been specifically considered for understanding and managing the flyrock risks.
For the purposes of this initial impact study, the blasting conditions for the entire mine site are assumed to be
consistent enough where the same set of site-specific modelling simulations can be applied within the whole pit
boundary. However, once blasting commences, site-specific data can be collected on a blast-by-blast basis to
collect historical data to better predict the effects of ground vibration, air overpressure, and flyrock for future blasts.
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

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INITIAL BLASTING
AREA
590 ft F,-,,(-B-IMIARI
Figure 1—Mine property and pit boundaries in relation to AO/s and neighboring quarry
Assumed blasting parameters
The potential impacts of the blasting activities are dependent on the assumed blast design parameters, and those
parameters used for the vibration, overpressure, and flyrock simulations are shown below.
Northeast A & West A: Northeast 8
• 6" holes 0 3.5" holes
• 35' deep 0 35' deep
• 13' x 15' pattern 0 10' x 12' pattern
• 11' Stemming 0 11' Stemming
• 380 lb/hole 0 130 Whole
It is important to note that these blast parameters are for reference only and are subject to change once blasting
operations begin. Once more site-specific data is collected it will be possible to better customize and optimize the
blast designs to fit the needs of the operation from a safety and production standpoint.
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

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Community Impact—Blast Vibration
The ground vibrations generated from each blast will be measured with seismographs which record the peak
particle velocity (PPV) in in/s and vibration frequency in Hz. The "Z-Curve" (seen below in Figure 2)was developed
by the former United States Bureau of Mines (USBM) and is the accepted standard for plotting and reviewing the
blast vibrations on neighboring structures in the state of North Carolina. To maintain compliance, the PPV of the
ground motion shall not exceed the solid black line in Figure 2 as monitored at the nearest protected structure or
any other monitored structures.
,on
2 Nsec
D.009 h
O 1.0
w 0.75 Wsee
Cl
c] 0.50 1W,ec f
plaster �!
a
0.000 In
i 10 i0p
FREQUENCY.Hz
Figure 2—Z-Curve as developed by USBM
While it's impossible to reliably predict the exact PPV for the planned blasting activities at this stage it is possible to
predict the likely upper limit of the PPV with a high level of confidence. These predictions will be based on the
assumed blast parameters, the geologic characteristics of the rock, and the proximity to the monitoring location(s).
The blasting history from the previous four years at a neighboring quarry was analyzed because it features similar
geology and is in close proximity to the Albemarle Mine. This historical data was used to calculate a site-specific K-
factor of 226, with an attenuation exponent of-1.66, which were used when predicting the approximate PPV values
for this study using the following equation. The vibration frequencies cannot be reliably predicted at this stage so
the impact study will focus on predicted PPVs.
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

•*> AUSTIN POWDER
/ D \-1.66
PPV = K I I
• PPV= Peak Particle Velocity (in/s)
• M = Maximum instantaneous explosive charge per delay (lb)
• D = Distance (ft)
• K= Site-specific factor
• n =Attenuation exponent
Initial blasting is expected to take place in the Northeast section of the mine with the closest point being
approximately 1,750'from the nearest protected structure (NPS). Based on the Northeast assumed blasting
parameters and the preliminary site-specific K-factor, the initial simulations calculate a likely maximum PPV of
approximately 0.13 in/s at that distance. These PPV levels will not have adverse effects on the integrity of the
neighboring structures and will remain within the limits of the Z-Curve regardless of the Hz. Figure 3 below shows
the simulated vibration contours for a representative initial blast in the Northeast area of the pit and the neighboring
properties.
Bounziary
See ft
Figure 3— Vibration contours from highest simulated blast parameters in Northeast blasting area
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

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As blasting progresses west, and south, the minimum distance to the various NPSs will change with each blast.
Based on the current extents of the pit boundary, the closest blast to an NPS would be approximately 1,140'. Using
the same assumptions from the initial simulations, the likely maximum PPV at this nearest distance is simulated to
be approximately 0.265 in/s. Although the calculated PPV levels increased compared to the Northeast blast, these
PPV levels will not have adverse effects on the integrity of the neighboring structures and will remain within the
limits of the Z-Curve regardless of the Hz. Once blasting operations commence, the recorded ground vibration for
each blast can be used as an additional data point to further calibrate the K-factors as well as identify the most
effective timing sequences to best control blast vibrations. This can then be used to better predict the PPV and
frequencies for subsequent blasts and drive necessary adjustments for future blast designs. There are numerous
cutting-edge products, tools, techniques, and blast design modifications which can be implemented if ground
vibration levels need to be more accurately controlled.
The results of the ground vibration modelling provide a high level of confidence that blasting can be safely executed
while maintaining compliance with North Carolina's requirements and minimizing negative effects on neighbors and
their properties.
Community Impact—Air Overpressure
Air overpressure is the energy that escapes from a blast into the atmosphere in the form of sound waves and is
measured in decibels (dB). The same seismographs used to measure the ground vibration will also be measuring
the air overpressure on each blast using a dedicated microphone. The state of North Carolina requires air
overpressure readings fall below 133 dB when using a 2.0 Hz microphone for each blasting event. There are certain
controllable blast parameters that will have significant impacts on the resulting overpressure for a blast such as face
burdens, distance and orientation to the monitoring location, hole loading configuration, initiation time and sequence,
and more. Using the Northeast A assumed blast parameters, paired with a review of the orientation and proximity of
the proposed blasting activities we can simulate the likely overpressure readings at neighboring properties. Figure 4
shows the projected overpressure contours based on the same representative blast design in the Northeast corner
of the mine property from the vibration analysis.
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

•*> AUSTIN POWDER
'"114 dB
Blast
Direction
Blast 110dB
Direction
120 dB
see ft
'109 dB
133 d6
Figure 4— Overpressure contours based on northeast blast simulation
The white arrows in Figure 4 indicate the simulated face orientation which influences the modelling. The modelling
resulted in higher overpressure in the directions of the free face which is consistent with what would be expected in
practice. In this simulation, the modelled overpressure readings at the plotted NPSs range from about from
approximately 109 dB - 114 dB. This highlights how proper positioning of the free face for each blast can help
managed the effects of overpressure.
As blasting progresses west, and south, the minimum distance to the various NPSs will change with each blast.
Based on the current extents of the mine boundary, the closest blast to an NPS would be approximately 1,140' at
which point the blasting will likely be oriented away from the NPS. Another representative model was run using the
West A assumed blast parameters and positioned in the western extent of the mine as depicted by Figure 5 below.
Those modelled overpressure readings at the plotted NPSs range from about from approximately 113 dB - 120 dB.
Even though the blast was oriented away from the monitors, the reduced distance led to higher modelled
overpressure values.
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

•*> AUSTIN POWDER
PTO d B
113 dB
120 i
133 d8
Blast
Direction
Figure 5— Overpressure contours based on western blast simulation
It should be noted that some environmental factors can affect overpressure transmission such as wind, temperature,
cloud cover, and more. However, as blasts are executed, the recorded air overpressures for each blast can be used
as a data point to establish a site-specific history. Alternative techniques can be applied with this data to further
minimize the resulting overpressure like reorientation of the blast, adjusting the stemming material, altering certain
blast design parameters, and applying unique timing solutions.
The results of the overpressure modelling provide a high level of confidence that blasting can be safely executed
while maintaining compliance with North Carolina's requirements and minimizing perception of blasting on neighbors
and their properties.
Community Impact—Flyrock
One of the primary safety concerns due to blasting is the potential for flying rock or material being propelled from a
blast. Flyrock can be generated either from the top (collar)or from the front (free face) of a blast. It is of paramount
importance that all shots are designed to have sufficient confinement in the form of adequate stemming and
adequate face burdens to help minimize the risk potential for flyrock with each blast.
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

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The flyrock risk profile simulations factor in the scaled depth of burial, face burdens, elevation, and orientation of
each modelled blast to project maximum potential flyrock risk distances. It should be noted that these are not
predictions of expected flyrock distances, but a maximum risk profile to use when factoring in flyrock risk mitigation
plans. Figure 6 below shows a flyrock risk assessment map based on the Northeast A blast design parameters
located in the Northeast corner of the mine property.
1.5 Safety
Factor Ring
See ft_
so
Figure 6—Example flyrock risk assessment map based on Northeast A design parameters
The red ring in Figure 6 represents the maximum potential flyrock risk based on the assumed blast design
parameters, and the yellow ring represents an arbitrary but definable safety factor added on top of the maximum
projection. For this simulation a safety factor of 1.5 was used. This feature can be used to represent minimum
required personnel clearance zones for added safety when planning and executing flyrock risk mitigation plans.
The assumed blast parameters used for the simulation in Figure 6 show a flyrock risk profile which extends beyond
the Albemarle Mine's property line. This does not imply flyrock will travel off-property, but it does show the potential
exists for material to be projected throughout the Flyrock Risk Area if any holes lose confinement during the blast. In
this scenario, the probability of material being projected off property if any holes lose confinement, is approximately
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

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9% from the free face and 42%from the collar in this specific simulation. If a simulated flyrock risk profile is deemed
unacceptable, additional simulations can be run using alternative blast design parameters. Figure 7 below shows an
adjusted flyrock risk area after using the Northeast 8 assumed blast design parameters and the same blast location.
1.5 Safety
Factm Ring
580 ft.
Figure 7—Example flyrock risk assessment map based on Northeast 8 design parameters
The flyrock risk profile is significantly reduced when using the West A assumed design parameters. The resulting
probability of material being projected off property in Figure 7, if any holes lose confinement, is approximately 1 in
42,000 from the free face and less than 1 in 1,000,000 from the collar. These adjustments are not intended to
represent actual planned design parameters but are meant to show the potential impacts on the flyrock risk
assessment for different blast designs.
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com

•*> AUSTIN POWDER
The flyrock risk map shown in Figure 7 confirms how realistic pattern adjustments can be introduced to reduce
potential flyrock risks as needed based on shot orientation and proximity to neighbors. Once blasting operations
commence, each blast can be individually reviewed to confirm actual rock movement post-blast, and this data can
be used to create a historical reference for typical rock movement based on blast parameters. This will help
improve the site-specific accuracy of the risk assessment model throughout different areas in the mine.
The results of the flyrock modelling provide a high level of confidence that blasting can be safely executed while
maintaining compliance with North Carolina's requirements and minimizing negative effects on neighbors and their
properties.
Summary
The blast vibration modelling shows a high level of confidence that blasting activities can be executed safely and in
compliance with North Carolina blasting regulations. The simulations we based on historical blast history data from
and adjacent quarry which adds an increased level of reliability to these initial projections. These simulations do
represent a generalization of the expected vibration readings and more advanced blast designs, technologies, and
techniques can be applied when blasting activities begin to improve the accuracy of the predictive modelling and
further reduce the resulting vibrations and impacts on the community.
The overpressure modelling also shows a high level of confidence that blasting activities can be executed safely
and in compliance with North Carolina blasting regulations. While overpressure is more difficult to predict with the
same precision as vibration the modelling does validate that the assumed blast parameters would yield safe and
compliant overpressure readings. As site-specific blasting results are analyzed necessary design, technique, and
planning process can be introduced to adequately control the overpressure performance of each blast.
The flyrock risk modelling shows a need for more conservative blast design parameters when blasting in close
proximity to neighboring properties. By defining the changing risks for different blasts across the mine, appropriate
planning, design, and execution can be applied to ensure all blasts are carried out safely and in compliance with
North Carolina blasting regulations.
AUSTIN POWDER COMPANY
25800 Science Park Dr. [e-mail]
Cleveland,OH 44122 wvvw.austinpowder.com