Dyno Alamance LLC Final Report (2) (1)

Report
To Mr. Chad M. Threatt
Alamance Aggregates LLC
PO Box 552
Snow Camp North Carolina
USA 27349
CC
From Stuart Brashear
Sr. Product and Applications Manager
DynoConsult
[e-mail]
Date February 22, 2019
DYNO
Dyno Nobel
DYNO NOBEL INC.
A business of Incitec Pivot Limited
2795 East Cottonwood Parkway
Suite 500
Salt Lake City, Utah
84121 USA
Telephone: [phone]
Fax: [phone]
www.dynonobel.com
Re: Review of Projected Impact of Blasting on Adjacent Structures for the
Proposed Alamance Quarry and Construction Materials Operation.
Mr. Threatt,
As requested, DynoConsult, a value-added division of Dyno Nobel, has reviewed proposed blasting
operations associated with the Alamance quarry. The findings of this review are presented for your
information.
OVERVIEW
With regard to the location of the Alamance quarry, proposed blasting operations have been assessed with
regard to potential impact on three primary structures;
• Nearby non -company owned residential structures
• Colonial Pipeline transmission lines located north of the proposed blast area
• Duke Power high voltage power transmission lines located north of the proposed blast area
Each of these structures will be assessed separately, but prior to any evaluation we must develop a generic
or baseline blast design to allow for projecting impact to these structures.

DYNO
Dyno Nobel
In discussions with management of Alamance Construction Materials and Dyno Nobel, a basic blast design
was developed to be implemented for initial blasting to develop the pit. Using Dyno Nobel empirical
formulas, the following design was developed to be used as a baseline blasting metrics for the reviews
included in this report.
Bench height 30 — 50 feet (Maximum value of 50 feet used for calculations)
Hole diameter — 5.0 inches
Stemming — 10 feet
Bulk Blasting Product — Titan XL TM with average density of 1.18g/cc
Using these metrics, we can calculate a maximum blast hole load of 432 pounds per hole
It is critical to note that this blast design is in no means the definitive design to be used during the life of
mine at Alamance quarry. Production requirements, changes in geology and advances in blasting
technology may necessitate modifications from this design. As all blasting will involve seismic monitoring,
The blast design is in effect a dynamic process that can be modified to meet changing results and impact
on neighboring properties to ensure that there is no impact related to blasting operations.
Blasting will commence at the southern extent of the pit boundary area with subsequent development
moving to the north. Given this mine plan, initial blasting will commence as far away as possible from both
the Colonial pipelines and the Duke Power transmission lines.
BLAST EFFECTS VARIABLES
In the absence of actual seismic data from blasting, we rely on calculations developed by federal research
agencies and accepted industry standards to project blast effects with regard to nearby structures. To
project potential vibration levels at adjacent properties and rights -of -way, four metrics are required:
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Dyno Nobel
• A reference explosive weight per "delay'
• The distance from the blast to the structure in question
• An attenuation rate for transient ground vibration
• A Y- intercept value for the level of confinement in the blast
The first two variables can be easily sourced based on the blast design and physical location of the blast
relative to structures. The last two variables must be based on industry or regulatory standards that have
been recommended to allow this type of projection of values.
With the introduction of electronic detonators into the industry, the methodology behind determining the
maximum charge value to be used for calculating transient vibration has changed. Previously charge
weight values for vibration calculation were based on the USBM Scaled Distance formula which uses a
delay window of 8 milliseconds to derive maximum charge weight. With the introduction of precision,
programmable electronic detonators, this criterion no longer could be used. The inherent accuracy of the
electronic detonator allowed for the use of destructive interference software technology to create timing
sequences that actively cancelled vibration created from each hole detonation'. This resulted in
significantly lower vibration effects even when the calculated charge weight for vibration calculations using
the 8-millisecond window increased by several times the normal hole load value'.
For the purposes of this report, we have defined the maximum explosive charge weight as the maximum
charge weight in any given hole in the blast.
The variables related to attenuation and blast confinement have been developed from regression analysis
performed on hundreds of blast events by various research groups. In this report, we have used variables
developed for three different quarry blast scenarios. Two calculations use variables developed by the
United States Bureau of Mines and one is from the Blasters Handbook, 18t" Addition. The values that will
be used for our assessment are shown on the table below.
' D Anderson, S Winzer, A Ritter, J Reil. "A Method for Site -Specific Prediction and Control of Ground Vibration from Blasting".
International Society of Explosives Engineers 11t" Annual Conference on Explosives and Blasting Techniques, San Diego,
California 1985.
2 S Brashear, R Cook. "Diagnosing and Modifying Off -Site Blast Effects by Seismic Means — A Case Study". International Society
of Explosives Engineers 22"d Annual Conference on Explosives and Blasting Techniques, Orlando, Florida USA 1996.
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Dyno Nobel
Source
Blast Type
Attenuation Value
Confinement (y intercept)
USBM3
Average
-1.38
52
USBM4
Worst Case
-1.38
138
ISEE5
Average
-1.60
160
Fig. 1 — constants for prediction of ground vibration
COLONIAL PIPELINE RIGHT OF WAY
Concerns over impact on the Colonial Pipeline's gas transmission lines that run through the northern
portion of the permit area have been relayed to us. In conversations with Colonial Pipeline representatives,
there are two criterion that must be met for Colonial to lend their blessing for blasting operations at the
Alamance quarry.
• Measured transient ground vibration at the pipeline right of way must be below 1.0 ips.
• Calculated Scaled Distance values for shot designs must be at a value of 51 or higher to alleviate
creating a "Blasting Encroachment" that would trigger the need to reduce transmission pressures in
the lines for that given blast.
While all calculations for this report are based on the Colonial Pipeline value of 1.0 ips, it should be noted
that this value is significantly below established criteria for the protection of buried pipelines.s
Using scaled drawings provided by Alamance Aggregates LLC and confirmed by use of the Alamance
County GIS, initial blasting for the quarry will take place approximately 2,675 feet from the Colonial right of
3 United States Bureau of Mines Bulletin 656. "Blasting Vibrations and their Effects on Structures". Duval, et. al. US Department of
the Interior, Washington DC 1971.
4 United States Bureau of Mines Bulletin 656. "Blasting Vibrations and their Effects on Structures". Duval, et. al. US Department of
the Interior, Washington DC 1971.
5 International Society of Explosives Engineers. "Blasters Handbook". 18th Addition. 2014. Cleveland Ohio
6 United States Bureau of Mines Report of Investigation RI-9523. "Surface Mine Blasting Near Pressurized Transmission Pipelines.
D. Siskind, et. al. US Department of the Interior, Washington DC 1994.
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way. Using this distance, and the expected charge weight of 432 pounds per blast hole, the calculated
ground vibration, using the values shown above are as shown.
har a Distance SD PPV
432 1 2675 1 128.701 1 0.169
tic3��:1r�'1•�:�[i7�■<iIiL�11
432 1 2675 1 128.701 I 0.067
Upper Bounds BU 656 (Quarry Production Blasts Worst Case)
Average BU 656 (Quarry Production Blasts Average)
ISEE Blasters Handbook
All projected Scaled Distance and PPV values are well below the suggested Colonial Pipeline criteria.
As blasting moves closer to the right of way vibration amplitude is expected to increase. At full maturity, the
closest blasting will ever take place with relation to the pipelines will be a distance of approximately 1,175
feet. Modifications to the blast design can be made as required in order to maintain transient vibration
levels well below the requirements of Colonial Pipeline. However, even if the proposed initial blast design
was to remain static, the expected vibration levels would be.
har a Distance SD PPV
432 1 1175 1 56.53 0.527
1 432 1 1175 1 56.53 I 0.199 1
432 1 1175 1 56.53 I 0.251
Upper Bounds BU 656 (Quarry Production Blasts Worst Case)
Average BU 656 (Quarry Production Blasts Average)
ISEE Blasters Handbook
Again, transient vibration levels and Scaled Distance value remain below the criteria set forth by Colonial
Pipeline.
Block Motion
The Colonial Pipeline agent expressed concern over potential block motion impact on the gas transmission
lines. Block motion or physical heaving of the rock mass by a blast event in quarry blast operations differs
from that experienced for trenching as is utilized for pipeline construction. The presence of a free face, or
open space in front of the blast provides the rock impacted by explosives to follow the path of least
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Dyno Nobel
resistance and move forward into the open pit. The lack of rock movement behind the blast can be seen by
the visual observations of the location of the last row of blast holes in the newly created face.
In the picture above, it can be seen that all rock motion from this blast moves outward to open air. There is
no disturbance of the material located behind the last row of holes.
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Dyno Nobel
In the picture above, the location of the last row of holes from the preceding shot are clearly evident,
showing very little damage and no movement behind the last row of holes in any given blast.
Given the distance from the pipelines to the life of mine extent of mining operations, there is no chance of
any block motion impacting the buried pipelines in question.
DUKE ENERGY TRANSMISSION LINES
Duke Energy has provided Alamance Aggregates with guidelines for blasting in the vicinity of transmission
towers. While these guidelines are designed primarily for contractor blasting within the transmission line
right-of-way (ROW), we can apply them to proposed blasting at the quarry.
• No closer than 150 feet from structure component or guy wire for 500KV or higher lines.
• No closer than 75 feet from structure component or guy wire for 230KV-340KV lines.
• No closer than 50 feet from structure component or guy wire for 44KV — 200KV lines.
• No closer than 100 feet from any angle structure.
• Lattice towers are to be measured from closest structure leg, not center of structure.
• All blasting within 700 feet of any structure shall be monitored with a seismograph.
• Recorded vibration levels shall not exceed 2.0 inches per second (ips).
In again reviewing documents provided by Alamance Aggregates LLC and via the Alamance County GIS,
the transmission lines run on an approximate parallel direction to the pipelines and are approximately 350
feet closer to the quarry pit boundary. Calculated distances are 2,336 feet from the initial blasting area and
776 feet for life of mine boundary.
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Dyno Nobel
Q Rr
4 �m
` 5P198391,0 u
j APPAR
776'
xaas• I I
1 �
�1 ; vcim
r ! r
l l I
uN 1
l � r
' ' I
Using a value of 2,336 feet for the distance from initial blasting to the closest transmission tower, the
projected vibration values are;
Charcie
Distance
SD
PPV
432
2336
112.39 1
0.204
Upper Bounds BU 656 (Quarry Production Blasts Worst Case)
0.077
Average BU 656 (Quarry Production Blasts Average)
432
2336
112.39
0.084
ISEE Blasters Handbook
432
2336
112.39 1
Similarly, using a minimum life of mine distance of 776 feet, we get the following results.
Char a
Distance
SD
PPV
432
776
37.34
0.934
Upper Bounds BU 656 (Quarry Production Blasts Worst Case)
1 0.352
Average BU 656 (Quarry Production Blasts Average)
432
776
37.34
0.488
ISEE Blasters Handbook
432
776
37.34
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Dyno Nobel
A comparison of the values associated with proposed blasting, both vibration levels and distances from
Duke Energy structures shows blast vibration values and distances well within the criteria set forth by Duke
Power.
RESIDENTAL STRUCTURES
Significant research has been performed over the decades on the effect of blasting on residential
structures. Federal agencies such as the US Bureau of Mines (USBM) and the Office of Surface Mining
Reclamation and Enforcement (OSMRE), both agencies of the Department of the Interior, have performed
research on the effects of blasting as well as monitored independent research performed by academic
institutions and industry sources. As a result of decades of research, a definitive safe blasting criterion was
developed by the USBM in 1980 that still is considered internationally and the most effective safe blasting
criteria'. Attempts at disproving or documenting damage to structures from blasting in accordance with this
criterion have never been verified and it is considered statistically a zero percent possibility of damage for
blasts that meet this standard.
The criteria developed by the USBM is a variable standard of ground vibration based on the frequency of
transient vibration motion. These criteria show allowable peak particle velocity values ranging from 0.50
inches per second to 2.0 inches per second depending on the frequency spectra of the associated ground
vibration. This safe blasting standard is graphically shown in the USBM report as the Appendix B
Alternative Blasting Level Criteria and is shown below.
7 USBM Report of Investigations RI-8507. "Structure Response and Damage Produced by ground Vibration From
Surface Mine Blasting". D Siskind, et al. Washington DC 1980.
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APPENDIX B ALTERN TJVE BLASTING LEVEL CRITERIA
Safe blastin vi&ralton criteria were developed
for residential strnUures, htiV3'ILK CWU frexluency
ranges 3 rnrj it sharp disonntinuity at 40 Ha {table
1a]- There are blasts that represent an inter-
mediate frequency case, heist higher than the
urucLure resunaneer,(4 to 12 H4-ind lower gran
40 lie. The criteria of tabk 15 apply equally to
a 35-]Hz ands I Q-Hz ground vitkMjOn. AhlLOugb
u
u
t
0
J
w
W
J
U
Ir
d
EL
10.0
f.0
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Dyno Nobel
titsppoonsm es and daa&* potentials are verp
h differexrr_
Using bush the measured Structure ampliri•
motions frig- 59) and damage surnrrraries (FrpL 52
and 54), a uncrother set of Criteria was devel-
oped. These erkeriz havc more sr.vere meas•
unng rcquiremenrs, iuYulving both, displacc-
Memi.ud vrbulty (Fig. B—Il .
1 10 I 100
FREOLICKY, 4Az
Figure 6-1_—Safe kvrls of blasting vih"AUn For heMses vying * Combination of velocity $nd
displiitmeoL
To show compliance with this standard, which has been adopted by the state of North Carolina for
regulated mining operations, seismograph data recorded from blasting events is automatically displayed
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Dyno Nobel
with the USBM sliding scale. Compliance can be proven by either a review of the ppv values recorded by
the unit or by a visual inspection of the blast data as shown with the USBM Appendix B criteria
superimposed on the data plot.
The location of the operating pit for the Alamance Aggregates operation is situated in the center of the
permitted property in a rural area of Alamance County. As a result, the distances between mining
operations (drilling and blasting) remain large. In reviewing data provided by Alamance Aggregates LLC
and reviewing via the Alamance County GIS, the following distances and projected vibration levels have
been calculated.
Owner Location Distance PPV PPV PPV
Minimum Worst Average ISEE
Norman Jackson
262 Clark Rd
1,250
0.46
0.17
0.22
Deborah Sanders
8900 Snow Camp Rd
1,800
0.28
0.11
0.12
Timothy Mulrooney
9.065 Whitehouse Ct
1,225
0.47
0.18
0.22
Brian Lee
1732 Quackenbush Rd
1,440
0.38
0.14
0.17
This review shows that even using the worst -case blasting environment (heavy confinement) and the worst
case USBM safe blasting criteria limit of 0.50 ips (low frequency, plaster on lathe interior), blasting at the
closest location to these structures life of mine still indicates vibration levels within the USBM safe blasting
standards without any modification from the initial blast design.
SUMMARY CONCLUSIONS
A review of adjacent properties has been performed to determine what, if any impact proposed blasting
operations associated with the Alamance Aggregates LLC operation in Snow Camp NC would have on
these locations. Using established safe blasting criteria and results of recent studies and investigations
DynoConsult can find no evidence that proposed blasting at this location will have any impact on adjacent
structures as outlined in this report, even when the mine operation reaches full life of mine dimensions.
Review of proposed criteria for the protection of the Colonial Pipeline ROW and the Duke Energy ROW
have been compared to projected blast vibration values. All calculations lead to evidence that blasting
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Dyno Nobel
poses no threat to either Colonial Pipeline or Duke Energy structures located in proximity to the Alamance
Aggregates LLC mining plan.
Should you have any questions or require additional information regarding information contained in this
report, please do not hesitate to contact me at any time.
Respectfully submitted,
sekwr� C Erzhea-
Stuart Brashear
Sr. Product and Applications Manager
DynoConsult
A Division of Dyno Nobel Inc.
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APPENDIX 1
Charge weight per foot calculator
Chg wt = (hole diameter2)x product density x 0.3405
Chg. wt. per foot = (5.0)2 x 1.18 x 0.3405
Chg. wt. per foot = 25 x 1.18 x 0.3405
Chg. wt. per foot = 10.04 lbs./loaded foot
Charge weight per hole
Chg wt per hole = (face height + subdrill — stemming) x 10.04
Chg. wt. per hole = (50 + 3 — 10) x 10.04
Chg. wt. per hole = 43 x 10.04
Chg. wt per hole = 432 lbs.
DYNO
Dyno Nobel
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Blast design calculations
APPENDIX 2
Shot Specific Data
Actual Burden
Actual Spacing
Bench Height
Decks (total ft)
Stemming
Subdrill
Rock Density
tons per yard
Explosive Density (avg)
Energy (cal/g)
VOID
13
13
50
0
10
3
2.7
2.274
1.18
680
17100
Yds/hole
Tons/hole
Charge/ft
Charge/hole
313
712
10.04
432
Powder Factor (tons/lb)
1.65
Powder Factor (lbs/yard)
energy (kcal/yd)
total energy (kcal/ton)
1.38
426.1
187.3
DYNO
Dyno Nobel
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APPENDIX 3
Vibration calculation formula
distance from blast —b
PPV = k
chg weight/hole
Where K = y axis intercept value
Where -b = slope of vibration attenuation rate
Source
Blast Type
Attenuation Value
Confinement (y axis intercept)
USBM8
Average
-1.38
52
USBM9
Worst Case
-1.38
138
ISEE10
Average
-1.60
160
8 United States Bureau of Mines Bulletin 656. "Blasting Vibrations and their Effects on Structures". Duval, et. al. US Department of
the Interior, Washington DC 1971.
9 United States Bureau of Mines Bulletin 656. "Blasting Vibrations and their Effects on Structures". Duval, et. al. US Department of
the Interior, Washington DC 1971.
11 International Society of Explosives Engineers. "Blasters Handbook". 18th Addition. 2014. Cleveland Ohio
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