Wake Stone Quarry Noise Study Protocol (9-2-20)

WSP USA, Inc.
100 Summer Street
Boston, MA 02111
(617) 426 - 7330
www.wsp.com/en-US
MEMORANDUM
To: Sam Bratton (Wake Stone)
From: Erich Thalheimer (WSP)
Date: September 2, 2020
Project Name: Wake Stone Triangle Quarry
Project Number: 30900418.000
Subject: Wake Stone Quarry Noise Study Protocol
The purpose of the following protocol is to describe the technical rationale and methodology for the
upcoming noise study involving the Wake Stone Triangle Quarry located at 222 Star Lane in Cary,
North Carolina. Wake Stone has been operating a stone quarry mine at this site since the early
1980s and now wishes to expand to a second quarry pit immediately to the west of the existing pit.
However, concern has been expressed with possible noise consequences in the adjacent Umstead
State Park towards the north due to the expansion of Wake Stone's mining operations.
This protocol will include sufficient study actions to be responsive to the NCDEQ's letter of 7/23/20,
the NCDPR letter of 5/8/20, and the letter of opposition written by Dr. Noral Stewart dated
7/13/20. The study will be conducted by trained acoustical staff (WSP) headed by an acoustical
engineer with 35 years of experience who is Board Certified by the Institute of Noise Control
Engineering (Appendix A).
Step 1: Literature Search
WSP will research and summarize noise criteria from around the country evaluating park areas as
noise -sensitive receptors. Possible sources of information could come from FHWA, FRA/FTA, EPA,
NPS, and technical papers in the INCE library. This will be an important task to help define what is
meant by "significant adverse effect" or "harmful noise impacts" with respect to quarry noise
radiating into Umstead Park. The results will provide a general awareness of relevant noise criteria
applicable to parks. WSP will also briefly describe the original noise studies done in the 1980s, but
only for the sake of understanding them, not for reconciling them with today's results.
Step 2: Existing Noise Measurements
WSP will measure existing noise levels in Umstead State Park to document current conditions. This
task will be important for establishing ambient noise levels for comparison against future modeled
noise levels. As shown in Figure 1, six (6) sites shown with yellow pins are proposed for performing
long-term noise measurements over the course of a week. The three (3) sites shown with red pins
are proposed short-term noise monitoring sites meant to augment the long-term noise data. These
sites have been selected to spatially cover the park to sample different noise environments;
including near the quarry, near residences, near roadways, near RDU airport, and far away from
anything where ambient noise levels could be quite low. Areas in the park referred to as having
"frequent human use" will get priority, such as trails, camp grounds and picnic areas.
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WSP is in the process of obtaining a Research Permit to enter the park to deploy the long-term sound
monitors. All noise monitoring instrumentation used in this study will comply with ANSI Standard
S1.4 for accuracy and calibration. Larson Davis Model 720 environmental noise monitors will be
used for the long-term sites, and a Svantek Model 971 sound analyzer will be used for the short-
term measurements.
WSP will also measure noise levels due to current mining operations and the specific equipment
that would be utilized in the expansion pit. This will be accomplished using a hand-held sound level
meter, ideally as close as 50 feet from a given piece of equipment to ensure it is the dominant noise
source being measured. Thus, this task will require WSP accessing the existing quarry site to sample
noise levels from equipment currently in use. The results, referred to as equipment sound level
emissions, will be used as input for the development of the noise prediction model in the next step.
Figure 1. Proposed Noise Monitoring Locations
Step 3: Future Noise Modeling
WSP will model future noise levels from operations at the expansion pit to estimate the increase in
noise levels and potential noise consequences to recreational users in Umstead State Park. This task
would be performed using the Cadna-A noise model that implements ISO Standard 9613 for outdoor
sound prediction and propagation (https://www.datakustik.com/products/cadnaalcadnaa/).
Cadna-A is a sophisticated, three-dimensional, ray -tracing acoustical model used all over the world
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for these types of outdoor noise applications. Aspects affecting sound propagation such as terrane
elevation, ground cover, foliage, distance, intervening obstacles, and wind direction are all
accounted for in the Cadna-A model.
Future truck traffic and new pit equipment will be included in the noise model. Noise levels
associated with removal of the overburden will also be modeled. Other mining equipment sound
emission levels will be taken from the FHWA's Roadway Construction Noise Model (RCNM) which
WSP developed for FHWA back in 2007. Once the Cadna-A model is complete it will allow
quantification of the noise reduction benefits expected from proposed noise mitigation measures
(i.e. buffer area, perimeter wall, earthen berm, deeper pit floor, etc.) and to respond to the
hypothetical questions raised by Dr. Noral Stewart.
Step 4: Deliver Noise Report
WSP will develop a Noise Study Technical Report to submit to Wake Stone and NCDEQ for review
and approval. The report will summarize the technical methodology, evaluation criteria, noise
measurement data, noise modeling results, and findings and conclusions of the study. Existing
measured and future predicted noise levels will be tabularized at several discrete noise receptor
locations (Figure 1) and will be presented as sound level isopleth contours (Figure 2) overlaid on
the Umstead State Park area. In this manner it will be possible to visualize how quarry noise will
propagate away from the new pit in all directions. If NCDEQ has any review comments then WSP
will address them in a revised version of the noise study report.
Figure 2. Sound Level Isopleth Contours (Example)
0 - 30.0
NI/0 >= 40.0
6 0 >= 45.0
0==s5.0
>= 75 0
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Appendix A
Lead Acoustical Engineer's Credentials
Inca
The Institute of Noise Control Engineering
of the United States of America, Inc.
in recognition of
professional standing and contributions
attests that
MICA THALHEfMZR
a Member of the Institute
is
Board Certified
in Noise Control Engineering
For the Board of Directors
President
A �2/�
Secretary
200 i ,Joins
20104
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