HomeMy WebLinkAbout1.15 Noise study appendixWSA -BLUE PIT EXPANSION 2012
[Appendix E]
NOISE STUDY
DESCRIPTION /DETAILS: This section provides information
pertaining to the Noise Assessment, prepared by Engineering
Dynamics Incorporated.
THIS SECTION INCLUDES:
• March 2012 Application Materials (Updated)
NOISE ASSESSMENT
BLUE PIT EXPANSION
WESTERN SLOPE AGGREGATES, Inc.
GARFIELD COUNTY, COLORADO
January 2010
ane 2,01 Charges to, M�nin
Prepared by:
Howard N. McGregor
Registered Professional Engineer
State of Colorado, # 3928
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TABLE OF CONTENTS
Table of Contents
I. Introduction
II. Applicable Laws, Regulations, Ordinances and Land Zoning
A. Community Noise
B. State of Colorado Noise Law
C. Garfield County
D. Zoning of Adjacent Land 5
Page
2
3
4
4
5
III. Equipment Inventory and Noise Emission Levels 6
IV. Analysis
A. Approach 7
B. Mine Development 7
C. Initial Mining 7
D. Processing Plant — Noise Emissions 8
E. Mine Site Haul Trucks 9
F. Highway Haul Trucks 9
G. Reclamation 9
V. Conclusions and Recommendations 10
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I. INTRODUCTION
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This noise assessment report was originally prepared for Western Slope Aggregates under the direction of Ryan
Ellis of Greg Lewicki and Associates and addressed noise emissions and control thereof associated with the
proposed expansion of the Blue Pit Sand and Gravel Mine. Since the issuance of the Noise Assessment Report,
there have been changes in the zoning of the land to the west from residential /agricultural to industrial. Detailed
information regarding these changes was provided to Engineering Dynamics Inc. (EDI) by Mr. S. Mello, General
Manager, Western Slope Minerals, Carbondale, Colorado. The pit is located north of State Highway 82 and
between County Roads 100 and 103 in Garfield County, Colorado. The address of the Blue Pit is: 0304 Highway
133, Carbondale, Colorado.
The mining plan including drawings and maps necessary for the preparation of this Noise Assessment Report
were provided to Engineering Dynamics Inc. by Greg Lewicki and Associates. Other maps and drawings
showing equipment locations and access roads have been prepared by Greg Lewicki and Associates and are
included in the application package.
Topographical cross sections are included in the Applicant's submittal package.
On Tuesday, April 28, 2009, Mr. McGregor visited the Blue Pit Expansion Area and was given an extensive tour
of the site by Mr. D. Brown.
Engineering Dynamics Inc. has prepared noise impact assessment analyses and reports for the surface and
underground mining Industry since 1972. All of the work reported herein was performed by Mr. McGregor or
under his direct supervision. Howard N. McGregor is a registered professional engineer licensed to practice
engineering in the State of Colorado. Mr. McGregor holds Colorado Professional Engineer License Number
3928, which was obtained by examination.
This report will show that the proposed operation can meet State and County noise standards by employing the
mitigation measures described in this report.
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II. APPLICABLE LAWS, REGULATIONS, ORDINANCES and LAND ZONING
A. Community Noise
Community noise has been addressed by the Federal Government starting with the U. S. Environmental
Protection Agency, (EPA) 'Noise Control Act of 1972 ". In concert with that act, state and local
governments have enacted laws or ordinances regulating noise emission levels. Furthermore, these
laws clearly define measurement methodology and decibel limits in scientific terms. Some laws do,
however, include subjective assessments, which are considered outside of rigorous scientific evaluation
and for this reason can be highly variable. Subjective assessments or considerations will not be
addressed in this report for that reason.
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B. State of Colorado Noise Law
Section 25 -12 -103. Maximum Permissible Noise Levels
§(1) Every activity to which this article is applicable shall be conducted in a manner so that any noise
produced is not objectionable due to intermittence, beat frequency, or shrillness. Sound levels of
noise radiating from a property line at a distance of twenty -five feet or more therefrom in excess
of the dB(A) established for the following time periods and zones shall constitute prima facie
evidence that such noise is a public nuisance:
§(2) In the hours between 7:00am and the next 7:OOpm, the noise levels permitted in subsection (1)
of this section may be increased by ten dB(A) for a period of not -to- exceed fifteen minutes in any
one -hour period. This paragraph in the State of Colorado Noise Law has been interpreted to
mean that this 10 dB increase can occur once and only once during the daytime hours of 7:OOam
to 7:00pm and never during the nighttime hours.
§(3) Periodic, impulsive, or shrill noises shall be considered a public nuisance when such noises are
at a sound level of five dB(A) less than those listed in subsection § (1) of this section.
Examples
Periodic — pile drivers, impact wrenches, punch presses, jack hammers and compaction
equipment.
Impulsive — firearm, fireworks, blasting, high pressure venting.
Shrill — sirens, metal forming, warning devices.
§(5) Construction projects shall be subject to the maximum permissible noise levels specified for
industrial zones for the period within which construction is to be completed pursuant to any
applicable construction permit issued by proper authority or, if no time limitation is imposed, for a
reasonable period of time for completion of project. This section of the law has been interpreted
to include mine development as construction. Such construction would include access
roads, top soil removal and storage, set up of stationary equipment such as crushers, screens
and engine generators, installation of utilities and construction of earthen noise barrier berms.
Section 25 -12 -104 Action to Abate
The entire section was amended.in 2008 and made effective on August 5, 2008. The last sentence
of this section now reads:
The court may stay the effect of any order issued under this section for such time as is
reasonably necessary for the defendant to come into compliance with the provisions of this
article.
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Maximum Allowable Noise Levels
Zone
lam to next 7prn
7pm to next 7am
Residential
55 dB(A)
50 dB(A)
Commercial
60 dB(A)
55 dB(A)
Light Industrial
70 dB(A)
65 dB(A)
Industrial
80 dB(A)
75 dB(A)
§(2) In the hours between 7:00am and the next 7:OOpm, the noise levels permitted in subsection (1)
of this section may be increased by ten dB(A) for a period of not -to- exceed fifteen minutes in any
one -hour period. This paragraph in the State of Colorado Noise Law has been interpreted to
mean that this 10 dB increase can occur once and only once during the daytime hours of 7:OOam
to 7:00pm and never during the nighttime hours.
§(3) Periodic, impulsive, or shrill noises shall be considered a public nuisance when such noises are
at a sound level of five dB(A) less than those listed in subsection § (1) of this section.
Examples
Periodic — pile drivers, impact wrenches, punch presses, jack hammers and compaction
equipment.
Impulsive — firearm, fireworks, blasting, high pressure venting.
Shrill — sirens, metal forming, warning devices.
§(5) Construction projects shall be subject to the maximum permissible noise levels specified for
industrial zones for the period within which construction is to be completed pursuant to any
applicable construction permit issued by proper authority or, if no time limitation is imposed, for a
reasonable period of time for completion of project. This section of the law has been interpreted
to include mine development as construction. Such construction would include access
roads, top soil removal and storage, set up of stationary equipment such as crushers, screens
and engine generators, installation of utilities and construction of earthen noise barrier berms.
Section 25 -12 -104 Action to Abate
The entire section was amended.in 2008 and made effective on August 5, 2008. The last sentence
of this section now reads:
The court may stay the effect of any order issued under this section for such time as is
reasonably necessary for the defendant to come into compliance with the provisions of this
article.
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C. Garfield County
Garfield County has no ordinance or regulation addressing noise in general and relies upon Colorado
Revised Statutes, Title 25, Article 12, "Noise Abatement" for determination of compliance. However,
Garfield County has a supplemental Gravel Extraction Regulation and Section 5.17.03 titled
"NoiseNibration" addresses noise and vibration. This Garfield County Regulation resolves conflicts that
have occurred previously into the interpretation of CRS 25 -12 section 103 as to whether the noise limits
are determined by the zoning of the noise emitter property or the zoning of the receiver property. The
Garfield County Regulation clearly states in 5.17.03 § (2) that the noise limits are determined by the
zoning of the receiver property.
The Garfield County Supplemental Gravel Extraction Regulation and the Colorado Noise Law are silent
on another factor which is the setting of the sound level meter used during the measurement of the
noise. Most sound level meters have two settings available when using the A- weighting; the settings are
dB(A) fast and dB(A) slow. The dB(A) fast setting always indicates a dB(A) value that is equal to or
greater than the dB(A) slow setting. The difference can be as great as 10 dB(A) for non- steady noise
sources such as a dozer or front -end loader.
For the stationary equipment such as crushers, vibratory screens and conveyors, there is essentially no
difference . between the dB(A) fast and the dB(A) slow because the noise is constant or steady.
However, the dB(A) values used in the analysis section of this report (Section IV) are the maximum,
either measured or provided by the equipment manufacturer. They are not the average decibel value,
which could include minimum noise levels.
D. Zoning of Adjacent Land
1. North
A residence is located 868 ft. north of the boundary of Mining Areas 3 and 4 just north of the "Y"
intersection of County Road 103. The residence is at an elevation of 6180 ft. and due south at the
pit boundary the elevation is 6158 ft. There are two residences north of Mining Area 4; one is at a
distance of 880 ft. and at an elevation of 6180 ft. The second residence is at a distance of 712 ft.
and at an elevation of 6175 ft. All three residences are north of the irrigation ditch /pipe. There is a
50 ft. offset to the south from the edge of the permit boundary to the mining excavation.
2. South
Residential property is located to the south and across Hwy 82. The distance to the nearest
residential property from the Expansion Area is about 430 ft. and the distance from the mining limit
boundary is 480 ft. The residential property is lower than the mining limit boundary by about 80 ft.
therefore the line -of -sight between these two locations is broken. This is shown as cross section A-
A' in the drawing. titled "Western Slope Aggregates, Blue Pit, Visual Map 2, Cross - Section Map.
3. East
Due east of the existing mine and the mine Expansion Area is the Garfield County Waste Disposal
Area. This parcel of land has not fully been reclaimed and in all probability will never be rezoned to
residential. It could be rezoned to industrial. Additionally there is an enormous topsoil stockpile on
the eastern portion of Mining Area 1 that will remain in place until the mine nears its final reclamation
stage.
4. West
The Cerise property to the west has been approved by Garfield. County for gravel extraction and processing and
the site is now "Industrial" zoning. The noise limits at the western property line are now 80 dB(A) daytime and 75
dB(A) nighttime, CRS 25 -12 -103.
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III. EQUIPMENT INVENTORY AND NOISE EMISSION LEVELS
Table 1 presents a list of the equipment that will be in operation at the pit during development, mining and
reclamation. The noise emission levels for the equipment listed in Table 1 is presented as so many dB(A) at
100 ft. This avoids the confusion associated with the use of the sound power level dB. The 100 ft. dB value
can be used to determine the noise level at other distances by use of a simple calculation using logarithms.
However, the calculation does not include the effects of terrain, vegetation, vertical thermal gradients in the
atmosphere and wind and should be used only for initial analysis purposes.
Table 1
Mine
Site Construction and Development
Description
Qty
Mfg. I.D.
Equipment Usage
dB(A) @
100 ft.
Backhoes
2
Hatchi 450
Overburden Removal and Construction and
Pit Development
74
Mining of Material
Dozen'}
1
CAT D -I0
Distribution of Overburden during Reclamation
81
Sand and Gravel Excavation
Front -End
Overburden Removal -Sand and Gravel Excavation
Loader
2
CAT 988
Loading Crusher Bin loading Haul Trucks
for On -Site Transportation
76
Front-End
Overburden Removal -Sand and Gravel Excavation
Loader
2
CAT 980
Loading Crusher Bin loading Haul Trucks
for On -Site Transportation
76
Skid Steer
1
CAT -246
Area Clean up
71
Jaw Crusher
1
Cedarapids
2248 -
Primary Crushing
74
Cone Crusher
1
JPI-JCI
Secondary Crushing
71
Vibratory
Screens
Cedarapids
Separating of Rock Sizes
70
Conveyors
• 3
--
Stockpiling
65
66of at
Wash Plant
1
Production
the
receptor
Water Truck
1
4,000 Gal
Dust Control
63
Mine Site
CAT 730
Transport of Material to Crusher Area
Haul Trucks(2)
3
30 ton
Moving Crushed Products to Stock Piles
76
Backup Alarm
BRS107
White. Noise Backup Alarm
68
Highway Haul
•
Transport of Product to Market
Truck(3)
--
Misc.
15 mph speed limit on site
66
Concrete Plant
1
(1)
The Caterpillar Model D -10 has the highest noise emission of the D series dozers.
(2) Measurements taken by E. D. I. at the Cripple. Creek and Victor Gold Mine on 2/3/04.
(3) When on public roads the noise limit for trucks in excess of 6000 pounds gross weight is 86 dB(A) at 50 ft. or
80 dB(A) at 100 ft. per CRS 25 -12.
Field measurements of haul truck noise were taken by Engineering Dynamics Inc. on July 17, 2007 at truck
speeds of 15 mph, EDI Job No. C3610.
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IV. ANALYSIS
A. Approach
The noise assessment analysis presented in this section of the report is based upon the following two
requirements.
1. During development (construction) of the amended pit area the daytime noise limits shall not exceed
the maximum allowable for Industrial Zoning of 80 dB(A) at a distance of 25 ft. beyond the Blue Pit
Expansion property line in all directions CRS 25 -12 -103, §(5).
2. During production in the expansion area, the noise limits shall not exceed the maximum allowable for
Residential Zoning of 55 dB(A) during the daytime and 50 dB(A) during the nighttime at a distance of
25 ft. beyond the pit property line or at the receptor, CRS 25 -12 -103.
B. Mine Development
During mine development, which is considered a construction activity, the noise limits are as detailed in
CRS 25 -12 -103§ (5), which limits the maximum permissible noise levels specified for industrial zones,
that is: 80 dB(A) form 7:OOam to 7:OOpm.
Mine development will begin in already worked Area 1 then sequentially onto Areas 2, 3 and 4.
Overburden, which ranges from 4 to 7 ft. in depth, will be removed with the front end loader. The
maximum noise level to the north, south, east and west that will occur when there is a direct Tine -of -sight
and when the front end loader is at the closest property line are presented in Table 2.
Table 2
Maximum Noise Level during Mine Development
Front End Loader — 76 dB(A) at 100 ft.
Direction
Receptor
Noise Source Location
Maximum
Noise Level —
dB(A)
N
Home
North Edge of Areas 3 and 4
57
N
Home
North Edge of Areas 3 and 4
57
N /NW
Home
Northwest Corner of Area 4
59
S
Homes
Directly South of Areas 2 and 3
62
E
Property
Line
Eastern Property Line (closed landfill)
66
W
Property
Line
Western Property Line (Cerise Pit)
70
It can be seen in Table 2 that under the worst case conditions when the front end loader is at the western
mining edge and close to the property line that the noise level is 10 dB(A) less than the 80 dB(A)
permissible level specified in CRS 25 -12 -103 § (5). This noise level occurs only at the western mine
boundary. In all other directions the noise levels are much lower. Also, the duration of these noise
levels will only be several days.
C. Initial Mining
After mine development is completed and production commences the noise limits shall not exceed the
maximum allowable for Residential Zoning at a distance of 25 ft. beyond the Blue Pit property line or at
the receptor.
Excavation of material will start at the east face of the initial expansion area and the raw material will be
transported to the jaw crusher bin by the front end loaders. During initial production the crushing and
screening plant will remain at its present location and will always be below grade. The 55 dB(A) noise
contour or footprint will not extend beyond the top edge of the mine face to the north, south, east and
west. Elevations may be seen on the Site Plan.
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D. Processing Plant — Noise Emissions
The processing plant works as follows:
The front -end loader (CAT988) will dump the raw rock material into the jaw crusher feed bin. The
crushed rock and fines will then feed to vibratory screens located under the jaw crusher.
Rock of the selected size will be washed and go via conveyor to storage piles. Rock that is too large will
be transported via conveyor to the cone crusher where the material is reduced in size. From the cone
crusher, the material goes back to the vibratory screens, where it is separated by size, washed and then
conveyed to storage piles.
The processing plant will initially remain at its present location and then move in a westerly direction but
remain at the same level as the existing pit floor, which is 6110 ft.
Table 3 presents the stationary and mobile equipment that make up the processing plant and the noise
level of each. At distances greater than 100 ft., the processing plant can be mathematically treated as a
single noise source having the total noise emission of 80 dB(A) at 100 ft. as presented in Table 3.
Table 3
Processing Plant Noise Emission
Description
Manufacturer I.D. ('"
dB(A) @ 100 ft.
Front -End Loader
CAT988
76
Jaw Crusher
Cedarapids
74
Cone Crusher
JCI
71
Conveyors
Misc.
65
Vibratory Screen
- --
70
Total Combined Noise Level
80
(1) See Table 1, which details all of the equipment operating at the pit.
If the processing plant and the receptors (north, south, east, west) were all at the grade level or in the
direct Tine -of- sight, the 55 dB(A) noise level would occur at a distance of 1775 ft. in all directions. The
reduction of noise from the processing plant due to distance and the barrier effect of the intervening
terrain are presented in Table 4.
Table 4
Processing Plant Elevation — 6110 ft.
Direction
Rece for
p
Receptor
Height
Terrain
Height
Distance
Pit to
Receptor
Distance{')
Reduction
Terrain
Reduction
Receptor
Noise
Level-
Level-
dB(A)
N
Home
6180
6158
2800
28
6
46
N
Home
6180
6158
3400
30
6
44
N /NW
Home
6175
6158
4200
32
5
43
S
Homes
6110
6240
1400
23
22
35
E
Property
Line
6270
6270
1400(2)
24
20
36
1N
Property
Line
6180
6180
3300 {2)
30
5
45
(1) Reduction to the noise level of 80 dB(A) occurring at 100 ft.
(2) Pit property line
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It should be pointed out that the terrain reductions occur when the receptor is beyond the upper edge of
the pit and the line -of -sight from the receptor to the processing plant is broken. Otherwise, there is no
reduction in the noise from the plant at that receptor location due to the pit wall. Also, the data presented
in Table 4 are when all of the equipment is in operation including the front end loader. Such a situation
would not be continuous because, for example, the front end loader would be away from the crusher bin
when it was scooping up another load of rock.
E. Mine Site Haul Trucks
Mine site haul trucks are high capacity units capable of hauling up to 30 ton loads. The trucks will
transport material to storage areas near the processing plant where the front end loader will pick up the
material and dump it into the jaw crusher bin. The trucks will also be used to transport over burden to
storage areas. The mine site haul trucks will be limited in speed to 15 mph or less and will produce 76
dB(A) at 100 ft. and 55 dB(A) at an unobstructed distance of about 1000 ft. The only time this condition
would occur is when the trucks were transporting overburden to storages areas during development of
the Expansion Area during which time the 80 dB(A) permissible noise level, CRS 25 -12 -103 §(5), would
occur at distances of less than 100 ft. During mine production the trucks will initially start out at about 10
ft. below grade and the 55 dB(A) distance would be at 700 ft. As mining progressed the trucks will be
further below grade and the distance to the 55 dB(A) will become less and Tess and eventually be pulled
in to the pit edge.
F. Highway Haul Trucks
Highway haul trucks will be loaded with rock products or concrete and leave the pit via the access road
and onto Highway 82. Once the trucks are on Highway 82, they will be required to not exceed the
permissible noise limits of CRS 25 -12 -106 of 86 dB(A) at 50 ft. at speeds of less than 35 mph. Customer
haul trucks that exceed the 86 dB(A) may be denied access to the pit until they have been repaired.
There is a change in Crs -25 -12 -107 that is effective, July 1, 2010 and is as follows:
(1) Counties or municipalities may adopt resolutions or ordinances prohibiting the operation of motor
vehicles within their respective jurisdictions that produce noise in excess of the sound levels in decibels,
measured on the "AA scale on a standard sound level meter having characteristics established by the
American National Standards Institute, publication S1.4 — 1971, and measured at a distance of fifty feet
from the center of the line of travel and within the speed limits specified in this section.
This change removes the requirement that this section is applicable to of highway vehicles such as those
within the Blue Pit Expansion areas. However, Garfield County can still enact noise limits for highway
haul trucks that are less than those in CRS- 25 -12, for example; haul trucks on Highway 82.
G. Reclamation
Topsoil may be taken from the topsoil storage areas to the mined area using the dozer, front end loader
and haul truck. Distribution of the topsoil will be done with the front end loaders. Smaller equipment
such as a skid steer may be used for ditching and seeding. Most of the time during reclamation, the
equipment will be below grade.
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V. CONCLUSIONS AND RECOMMENDATIONS
1. Noise emissions during mine development (construction as defined in CRS 25 -12 -103 § (5) will not
exceed 80 dB(A) at 25 ft. beyond the existing or amended pit boundary.
2. During mine development noise emission levels from the front end loader at the homes to the north and
south will be less than 62 dB(A) when the front end loader is at grade level and at the closest property
line. At all other locations that do not abut to the mining boundary the noise level during development
will be less than 60 dB(A).
3. During mine production in any of the four mining areas, the noise level from mobile equipment occurring
at the homes to the north, northwest and south will be less than 55 dB(A) and intermittently lower. This
condition will only occur during the initial mining operations, as reining progresses and the mobile
equipment goes deeper and deeper, the noise level will decrease.
4. Noise levels from the processing plant will always be less than 46 dB(A) at the homes to the north,
northwest and south. The process plant will always be at an elevation of 6110 ft (the pit floor), even
when it is moved in an easterly direction.
5. All backup alarms will be of the white noise type and will be adjusted during installation to meet all
regulatory requirements.
6. Customer haul trucks that exceed the noise limits specified in CRS 25 -12 -107 may be denied access to
the pit until they have been maintained and are in compliance.
7. Ground vibration caused by any of the stationary or mobile equipment operating in the mine pit or on the
mine access road will not be perceptible. In addition, there will be no blasting of any type in the pit or
elsewhere on the mine property.
8. Noise measurements will be taken once the pit expansion area of the pit is in production to verify
compliance with CRS 25 -12 -103. Measurement results will be detailed in a report certified by a
Professional Acoustical Engineer registered in the State of Colorado.
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AIR EMISSION PERMITS APPENDIX F