DAQ-2024-004558

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DAQC-CI106540001-23
Site ID 10654 (B1)

MEMORANDUM

TO: FILE – UNITED STATES GYPSUM COMPANY – Sigurd Plant

THROUGH: Chad Gilgen, Minor Source Compliance Section Manager

FROM: Daniel Riddle, Environmental Scientist

DATE: November 2, 2023

SUBJECT: FULL COMPLIANCE EVALUATION, Minor, Sevier County

INSPECTION DATE: October 24, 2023

SOURCE LOCATION: 78 North State Street
Sigurd, 84657
DIRECTIONS: Follow State Street through Sigurd until you get to the turn
before the bridge. That turn leads into US Gypsum Company

SOURCE CONTACTS: Ernest Gibbs, Environmental Coordinator
435-896-2401 [e-mail]

OPERATING STATUS: Operating normally at the time of inspection.

PROCESS DESCRIPTION: US Gypsum Company (USGC) mines gypsum ore from one of
three pits and trucks ore to the processing plant. The gypsum is
dumped into a grizzly feeder that leads into a primary roll
crusher and then conveyed to a secondary crusher for sizing. A
conveyor then feeds the oversized ore back to the primary
crusher. The sized material is conveyed to a storage bin and fed
to the Raymond mills as needed, where it is crushed to produce
a fine powdered product. The material is then conveyed to the
calcining kettles and dumped into a hot pit. The material is then
conveyed to the board plant. Water is added to the gypsum with
additional chemicals to form a slurry paste. The paste is squirted
onto a backing sheet and spread to an even surface. The paste
congeals and is then covered with a top backing. The board is
conveyed on rollers to the natural gas fired kiln for drying. The
hard board is transferred to an end cutting and sizing area where
it is trimmed to size by automatic saws. The boards are then
stacked and trucked offsite. Baghouses and covered conveyors
control particulate emissions at the facility. The haul roads are
watered by a water truck to control fugitive dust or sprayed with
brine solution. The kettles and ovens burn natural gas for fuel.
Ready-mix joint compound production uses a mixture of
limestone and additives, and is controlled by a baghouse that
vents indoors.

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APPLICABLE REGULATIONS: Approval Order (AO) DAQE-AN106540011-20, dated October
29, 2020
NSPS (Part 60) IIII : Standards of Performance for Stationary
Compression Ignition Internal Combustion Engines,
NSPS (Part 60) -OOO : Standards of Performance for
Nonmetallic Mineral Processing Plants,
MACT (Part 63) -ZZZZ: National Emissions Standards for
Hazardous Air Pollutants for Stationary Reciprocating Internal
Combustion Engines,

SOURCE EVALUATION:

Name of Permittee: Permitted Location:

United States Gypsum Company - Sigurd Plant
78 North State Street 78 North State Street
Sigurd, UT 84657 Sigurd, UT 84657

SIC Code: 3275: (Gypsum Products)

Section I: GENERAL PROVISIONS

I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in the
UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to
those rules. [R307-101]

I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401]

I.3 Modifications to the equipment or processes approved by this AO that could affect the emissions
covered by this AO must be reviewed and approved. [R307-401-1]

I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by
the owner/operator, shall be made available to the Director or Director's representative upon
request, and the records shall include the two-year period prior to the date of the request. Unless
otherwise specified in this AO or in other applicable state and federal rules, records shall be kept
for a minimum of two (2) years. [R307-401-8]

I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators shall,
to the extent practicable, maintain and operate any equipment approved under this AO, including
associated air pollution control equipment, in a manner consistent with good air pollution control
practice for minimizing emissions. Determination of whether acceptable operating and
maintenance procedures are being used will be based on information available to the Director
which may include, but is not limited to, monitoring results, opacity observations, review of
operating and maintenance procedures, and inspection of the source. All maintenance performed
on equipment authorized by this AO shall be recorded. [R307-401-4]

I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns.
[R307-107]

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I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories. [R307-150]

Status: Out of Compliance. Emission limits on the #2 kettle and dust collector were
exceeded. See section II for more details. The source stated that there have been no
modifications to the equipment or processes. The equipment appeared to be properly
operated and maintained according to manufacturer recommendations. Records are kept
as required and were made available after the inspection. No breakdowns have been
reported since the previous inspection. An emissions inventory was submitted for 2020, and
emissions data are reported below.

Section II: SPECIAL PROVISIONS

II.A The approved installations shall consist of the following equipment:

II.A.1 Gypsum Plant
Source Wide

II.A.2 B1
#1 Pre-Stucco Treatment System (PST) Dust Collector: A baghouse, rated at 2,200 dscfm,
controlling the dust from two stucco storage bins and Entoleter Mill (rated at 22 tons per hour).

II.A.3 B2
#2 PST Dust Collector: A baghouse, rated at 1,953 dscfm, controlling the dust from the ball mill and
paper fiber cyclone.

II.A.4 B3
Mini-kettle PST: Removes additional water from stucco with a natural gas burner, rated at 3.0
MMBtu/hr.

II.A.5 B7
End Saw Dust Collector: A baghouse controlling the dust from sawing process, rated at 4,130 dscfm.

II.A.6 B8
Board Plant Mixer Vent: Vented through a bin vent within the plant, not emitted into the atmosphere
(listed for informational purposes only).

II.A.7 B9
Mini-kettle PST Dust Collector: A baghouse controlling the dust from the Mini-kettle PST, rated at
950 dscfm.

II.A.8 B10
Board-line Kiln/Dryer: Removes excess water in the slurry through three exhaust stacks (Wet End
B4, Recirculating B6, and Dry End B12) with two (2) natural gas burners rated at 48.0 MMBtu/hr
total.

II.A.9 B11
Stucco Storage Bins: Two storage bins that receive stucco discharged from the Hot Pit (both
enclosed in building).

II.A.10 B13
Dunnage Machine: Rated at 38 tons per hour with a baghouse (4,680 dscfm).

II.A.11 C1
Crusher System: Equipped with a baghouse (4,130 dscfm) controlling the emission streams from the
primary and secondary crushers (both enclosed in building), two 30-inch belt conveyors, dump
hopper, plate feeder, and vibrating feeder.

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II.A.12 M1
Rock and L.P. Storage Bin Dust Collector: A baghouse controlling the dust from four rock storage
bins and two landplaster storage bins. Rated at 3,317 dscfm.

II.A.13 M2
Raymond Mill Dust Collector: A baghouse controlling the dust from the Raymond Mill, rated at
2,180 dscfm.

II.A.14 M2-1
Raymond Mill: Mill system preheated by a 2 MMBtu/hr natural gas burner.

II.A.15 M3
#1 Kettle Dust Collector: A baghouse controlling the dust from #1 Kettle, rated at 400 dscfm.

II.A.16 M4
#1 Kettle: Removes the chemically combined water in the landplaster with a natural gas burner,
rated at 9.5 MMBtu/hr.

II.A.17 M5
#2 Kettle Dust Collector: A baghouse controlling the dust from #2 Kettle, rated at 1,090 dscfm.

II.A.18 M6
#2 Kettle: Removes the chemically combined water in the landplaster with a natural gas burner rated
at 10.6 MMBtu/hr.

II.A.19 M7
Hot Pit: Storage bin that receives discharge (Stucco) from both kettles. Equipped with a baghouse
rated at 1,363 dscfm.

II.A.20 Emergency Fire Pump Engine
Rated Capacity: 460 kW (617 hp)
Fuel: Diesel
Manufacture Date: 2019 or newer
Federal Standards: NSPS Subpart IIII/MACT Subpart ZZZZ

Status: In Compliance. All of the above listed equipment was found on site during the
inspection. M1 and M2 from Conditions II.A.12 and II.A.13 share an emission point.
The source was able to point out each baghouse and its corresponding stack. The
emergency fire pump engine is on site, but has not been installed yet.

II.B Requirements and Limitations

II.B.1 Gypsum Manufacturing Plant.

II.B.1.a The stacks identified below shall have the following minimum stack exit heights, as measured
from ground elevation:

Stack ID Stack Exit Height (ft)

C1 12
M1 55
M2 38.5
M3 50
M4 39
M5 57
M6 38
M7 47
B1 35
B2 58
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B3 50
B4 27.89
B6 33.75
B7 29.5
B9 52
B12 30
B13 29.5.
[R307-410-4]

Status: In Compliance. No variation in stack heights was observed at the time of inspection.
All stack heights match the measurements in this AO.

II.B.1.b Visible fugitive dust emissions from haul road traffic, mobile equipment in operational areas, and
other fugitive emission sources on site shall not exceed 20% opacity at any point. [R307-205]

II.B.1.b.1 Visible emission determinations shall use procedures similar to Method 9. However, the normal
requirement for observations at 15-second intervals over a six-minute period shall not apply.
Visible emissions shall be measured at the densest point of the plume but at a point not less than
1/2 vehicle length behind the vehicle and not less than 1/2 the height of the vehicle. [R307-205]

Status: In Compliance. No visible emissions were observed from plant buildings or stacks,
and no fugitive dust was observed on any haul road. The operation area was covered with a
layer of gravel around most of the buildings. They control nine miles of haul road with
water trucks. See attached Method 9 VEO form.

II.B.1.c Visible emissions from the following emission points shall not exceed the following values:

A. Crusher baghouse exhaust stack - 7% opacity
B. All other baghouse exhaust stacks - 10% opacity
C. All heater exhaust stacks - 10% opacity
D. All conveyor transfer points - 10% opacity
E. All other points - 20% opacity. [R307-401-8]

II.B.1.c.1 Opacity observations of emission from stationary sources shall be conducted according to 40
CFR 60, Appendix A, Method 9. [R307-401-8]

Status: In Compliance. No visible opacity was observed from any of these emission sources
during the inspection. Method 9 was utilized to determine emissions, see the attached VEO
form.

II.B.2 Natural Gas Combustion

II.B.2.a The owner/operator shall use natural gas as fuel in the combustion devices listed below:

A. Calcining Kettles (#1 and #2)
B. Board Drying Kiln
C. Raymond Mill pre-heater
D. Mini-kettle system. [R307-401-8]

Status: In Compliance. Only natural gas is used as fuel in the above combustion devices.

II.B.2.b The owner/operator shall not consume more than 627,800,000 standard cubic feet of natural gas
per rolling 12-month period. [R307-401-8]

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II.B.2.b.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new
12-month total by the 20th day of each month using data from the previous 12 months. Records
of consumption shall be kept for all periods when the plant is in operation. Natural gas
consumption shall be determined by examination of fuel supplier billing records. The records of
natural gas consumption shall be kept on a monthly basis. [R307-401-8]

Status: In Compliance. For the rolling 12-month period from Oct 2022 - Sep, 2023, a total
of 160, 338, 000 cubic feet of natural gas were consumed. Records were reviewed at the
time of inspection.

II.B.3 Roads & Fugitive Dust.

II.B.3.a The owner/operator shall comply with all applicable requirements of R307-205 for Fugitive
Emission and Fugitive Dust sources. [R307-205]

Status: In Compliance. The source operates with a FDCP that has not changed since the
previous inspection.

II.B.3.b The owner/operator shall use water application and/or chemical treatment on all unpaved roads,
and other unpaved operational areas that are used by mobile equipment to control fugitive dust.
[R307-401-8]

II.B.3.b.1 Treatment shall be of sufficient frequency and quantity to maintain the opacity limits in this AO
unless it is below freezing. If chemical treatment is to be used, the plan must be approved by the
Director. Records of water, and/or chemical treatment shall be kept for all periods when the plant
is in operation. The records shall include the following items:

A. Date of treatment
B. Number of treatments made, dilution ratio, and quantity
C. Rainfall received, if any, and approximate amount
D. Time of day treatments were made
E. Records of temperature if the temperature is below freezing. [R307-401-8]

Status: In Compliance. Water application records were reviewed from the summer of 2023.
The source operates several quarry pits that are connected by haul road. Detailed records
of gallons of water that are placed down are kept. On some days, no visit to any quarry is
made, so no unpaved haul roads are used.

II.B.3.c The owner/operator shall pave the in-plant access road, and shall periodically sweep, or spray
clean the road as dry conditions warrant or as determined necessary by the Director. Records of
cleaning paved roads shall be kept for all periods the plant is in operation.

The silt loading present on all paved in-plant access roads shall not exceed 0.7 grams per square
meter. Testing shall occur no less than once every calendar month unless testing is not possible
due to inclement weather such as snow/ice covered roads or freezing conditions that prevent
sweeping. Testing shall be as per AP-42, Appendix C, or other EPA-approved testing method, as
acceptable to the Director. The Director may require silt loading test of the paved in-plant access
roads at any time. Silt testing results shall be kept for all periods the plant is in operation.

Records of month-long inclement weather that prevent sweeping of in-plant access roads shall be
kept for all periods the plant is in operation. These records shall include dates and conditions that
prevented sweeping, including temperatures and precipitation records.

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The road lengths shall be as follows:

A. The in-plant, unpaved haul roads shall not exceed 1.5 miles in combined length
B. The in-plant, paved access roads shall not be less than 0.6 miles in combined length.
[R307-401-8]

Status: In Compliance. Both silt-loading records and sweeping records were reviewed at
the time of inspection. The entire paved area is swept once per month. The source had not
failed a silt-loading test in the past 12 months.

II.B.4 #1 PST Dust Collector (B1).

II.B.4.a The PST #1 fabric filter baghouse shall be sized to handle at least 2,200 dry-standard-cubic-feet-
per-minute (dscfm). All exhaust air from the #1 PST system and entoleter mill shall be routed
through this fabric filter baghouse before being vented to the atmosphere. [R307-401-8]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.5 #2 PST Dust Collector (B2).

II.B.5.a The PST system #2 fabric filter baghouse shall be sized to handle at least 1,953 dscfm. All
exhaust air from the #2 PST system and paper fiber cyclone shall be routed through this
baghouse before being vented to the atmosphere. [R307-401-8]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.6 End Saw Dust Collector (B7).

II.B.6.a The end saw fabric filter baghouse shall control process streams from the dry end bundler.

This fabric filter baghouse shall be sized to handle at least 4,130 dscfm for the existing
conditions. All exhaust air from this process shall be routed through this fabric filter baghouse
before being vented to the atmosphere. [R307-401-8]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.7 Mini-Kettle & PST Dust Collector (B9).

II.B.7.a The mini-kettle system fabric filter baghouse shall be sized to handle at least 950 dscfm. All
exhaust air from the mini-kettle system shall be routed through this fabric filter baghouse before
venting to the atmosphere. [R307-401-8]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.8 Board-line Kiln/Dryer (B10).

II.B.8.a The owner/operator shall not produce more than 938.4 thousand square feet of finished
wallboard from the Board Drying Kiln per calendar day. [R307-401-8]
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II.B.8.a.1 Wallboard production shall be determined by production billing records. Records of production
shall be kept daily for all periods when the plant is in operation. [R307-401-8]

Status: In Compliance. Records reviewed at the time of inspection show that in the past
year, the maximum daily production has been 678,000 square feet of Board Drying Kiln. A
typical daily production is 200,000 - 500,000 square feet. The source indicated that the
system is programmed to shut down before reaching the maximum in this requirement.

II.B.9 Dunnage Machine Baghouse (B13)

II.B.9.a The dunnage machine fabric filter baghouse shall control process streams from the dunnage
machine and the cut-back saw.

This fabric filter baghouse shall be sized to handle at least 4,680 dscfm. All exhaust air from this
process shall be routed through this fabric filter baghouse before being vented to the atmosphere.
[R307-401-8]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.10 Crusher System (C1).

II.B.10.a The owner/operator shall not operate the primary crusher for more than 12 hours per calendar
day. [R307-401-8]

II.B.10.a.1 The records of production shall be kept on a daily basis for all periods when the plant is in
operation. Hours of operation shall be determined by a supervisor monitoring and maintaining an
operation log. [R307-401-8]

Status: In Compliance. Shifts in the quarry take place from 6 am - 4 pm, so the maximum
that the crusher would ever run is 10 hours.

II.B.10.b The owner/operator shall not process more than 125 tons of material through the primary crusher
per hour. [R307-401-8]

II.B.10.b.1 To determine compliance with the process limit the owner/operator shall tabulate the amount of
material produced during each calendar day and divide this by the number of operational hours
for that calendar day to determine an average hourly rate. A calendar day is the period of time
from midnight to midnight. Records of throughput shall be kept for all periods when the plant is
in operation. [R307-401-8]

Status: In Compliance. Records reviewed at the time of inspection showed a maximum of
123.4 tons in one hour, with a typical day being 80 - 100 tons through the crusher per hour.

II.B.10.c The crusher system baghouse shall be sized to handle at least 4,130 dscfm. All exhaust air from
the primary crusher, secondary crusher, dump hopper, plate feeder, primary conveyor, secondary
conveyor, and vibrating feed chute shall be routed through this fabric filter baghouse before
being vented to the atmosphere. [R307-401]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

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II.B.11 Rock and L.P. Storage Bin Dust Collector (M1).

II.B.11.a The rock and landplaster storage bins fabric filter baghouse shall be sized to handle at least 3,317
dscfm. All exhaust air from the four rock storage bins and two landplaster storage bins shall be
routed through this fabric filter baghouse before being vented to the atmosphere. [R307-401]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.12 Raymond Mill Dust Collector (M2).

II.B.12.a The Raymond Mill fabric filter baghouse shall be sized to handle at least 2,180 dscfm. All
exhaust air from the Raymond Mill shall be routed through the Raymond Mill cyclone and then
routed through this fabric filter baghouse before being vented to the atmosphere. [R307-401]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.13 #1 Kettle & Dust Collector (M3).

II.B.13.a The calcining kettle #1 fabric filter baghouse shall be sized to handle at least 400 dscfm. All
exhaust air from the #1 calcining kettle shall be routed through this fabric filter baghouse before
being vented to the atmosphere. [R307-401-8]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.14 #2 Kettle & Dust Collector (M5).

II.B.14.a The calcining kettle #2 fabric filter baghouse shall be sized to handle at least 1,090 dscfm. All
exhaust air from the #2 calcining kettle shall be routed through this fabric filter baghouse before
being vented to the atmosphere. [R307-401-8]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.15 Hot Pit (M7).

II.B.15.a The hot pit fabric filter baghouse shall be sized to handle at least 1,363 dscfm. All exhaust air
from the two hot pits shall be routed through this fabric filter baghouse before being vented to
the atmosphere. [R307-401-8]

Status: In Compliance. Previous evaluations have found the unit sized to handle the
specified flow. Exhaust air appeared to flow through the correct pathway into the baghouse
before being vented to the atmosphere. The filtering system appears to control specified
emissions.

II.B.16 Emergency Fire Pump Engine Requirements

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II.B.16.a The owner/operator shall not operate the emergency fire pump engine on site for more than 100
hours per rolling 12-month period during non-emergency situations. There is no time limit on the
use of the engine during emergencies. [40 CFR 60 Subpart IIII, 40 CFR 63 Subpart ZZZZ,
R307-401-8]

II.B.16.a.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new
12-month total by the 20th day of each month using data from the previous 12 months. Records
documenting the operation of the emergency fire pump engine shall be kept in a log and shall
include the following:

A. The date the emergency fire pump engine was used
B. The duration of operation in hours
C. The reason for the emergency fire pump engine usage. [R307-401-8]

Status: Not Applicable. The fire pump engine is on site, but it has not been installed.

II.B.16.b The owner/operator shall install a non-resettable hour meter on the emergency fire pump engine
to determine the duration of operation. [R307-401-8]

Status: Not Applicable. The fire pump engine is on site, but it has not been installed.

II.B.16.c The owner/operator shall only combust diesel fuel that meets the definition of ultra-low sulfur
diesel (ULSD), which has a sulfur content of 15 ppm or less. [R307-401-8]

II.B.16.c.1 To demonstrate compliance with the ULSD fuel requirement, the owner/operator shall maintain
records of diesel fuel purchase invoices or obtain certification of sulfur content from the diesel
fuel supplier. The diesel fuel purchase invoices shall indicate the diesel fuel meets the ULSD
requirements. [R307-401-8]

Status: Not Applicable. The fire pump engine is on site, but it has not been installed. No
diesel fuel has been purchased or used to run this generator.

II.B.17 PM10 Compliance & Testing.

II.B.17.a A manometer or magnahelic pressure gauge shall be installed and maintained to measure the
differential pressure across the fabric filters in each baghouse. Static pressure difference across
the fabric filters shall be between 1.5 to 6 inches of water column, accurate to within plus or
minus 1.0 inch water column, in each case*. The pressure gauges shall be located such that an
inspector/operator can safely read the indicator at any time. The instruments shall be calibrated
according to the manufacturer's instruction at least once every 12 months. Recording of the
reading from each device is required on a once per operational week basis.

*Considering the prescribed accuracy of the pressure drop measurement devices, this means that
the acceptable range of pressure drop observations is 0.5 to 7 inches of water column.
[R307-401-8]

Status: In Compliance. All magnehelic pressure gauges were calibrated on April 12, 2023.
Records were viewed at the time of inspection.

II.B.17.b Crusher System Dust Collector (C1): The emissions to the atmosphere from the crusher system
baghouse exhaust stack shall not exceed the following rate and concentration at all times.

Pollutant lb/hr grains/dscf (68 degrees F, 29.92 in Hg)

PM10 0.35 0.01. [R307-401-8]

Status: In Compliance. From testing completed May 23 – June 1, 2022, PM10 emissions
were 0.0032 gr/dscf and 0.291 lb/hr. The source will complete another stack test in the near
future once their new AO is completed.

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II.B.17.c Raymond Mill Dust Collection (M2): The emissions to the atmosphere from the Raymond Mill
baghouse exhaust stack shall not exceed the following rate and concentration at all times.

Pollutant lb/hr grains/dscf (68 degrees F, 29.92 in Hg)

PM10 0.38 0.01. [R307-401-8]

Status: In Compliance. From testing completed May 23 – June 1, 2022, PM10 emissions
were 0.0014 gr/dscf and 0.057 lb/hr. The source will complete another stack test once their
new AO is completed.

II.B.17.d #1 Kettle Dust Collector (M3): The emissions to the atmosphere from the Kettle #1 baghouse
exhaust stack shall not exceed the following rate and concentration at all times.

Pollutant lb/hr grains/dscf (68 degrees F, 29.92 in Hg)

PM10 0.10 0.0285. [R307-401-8]

Status: In Compliance. From testing completed May 23 – June 1, 2022, PM10 emissions
were 0.0022 gr/dscf and 0.0290 lb/hr. The source will complete another stack test once their
new AO is completed.

II.B.17.e #2 Kettle Dust Collector (M5): The emissions to the atmosphere from the Kettle #2 baghouse
exhaust stack shall not exceed the following rate and concentration at all times.

Pollutant lb/hr grains/dscf (68 degrees F, 29.92 in Hg)

PM10 0.0934 0.01. [R307-401-8]

Status: Out of Compliance. From testing completed May 23 – June 1, 2022, the PM10 lb/hr
emission rates were measured at 0.1153. An Early Settlement Agreement was issued on
August 9, 2022 (see DAQC-953-22). The source submitted a NOI to adjust the emissions of
this baghouse and the new AO is currently under public review. No action is recommended
at this time.

II.B.17.f Hot Pit Dust Collector (M7): The emissions to the atmosphere from the Hot Pit baghouse exhaust
stack shall not exceed the following rate and concentration at all times.

Pollutant lb/hr grains/dscf (68 degrees F, 29.92 in Hg)

PM10 0.12 0.01. [R307-401-8]

Status: In Compliance. From testing completed May 23 – June 1, 2022, PM10 emissions
were 0.0010 gr/dscf and 0.0226 lb/hr. The source will complete another stack test once their
new AO is completed.

II.B.17.g #1 PST Dust Collector (B1): The emissions to the atmosphere from the #1 PST system baghouse
exhaust stack shall not exceed the following rate and concentration at all times.

Pollutant lb/hr grains/dscf (68 degrees F, 29.92 in Hg)

PM10 0.22 0.01. [R307-401-8]

Status: In Compliance. From testing completed May 23 – June 1, 2022, PM10 emissions
were 0.0028 gr/dscf and 0.0632 lb/hr. The source will complete another stack test once their
new AO is completed.

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II.B.17.h Mini-Kettle Dust Collection (B9): The emissions to the atmosphere from the Mini-Kettle
baghouse exhaust stack shall not exceed the following rate and concentration at all times.

Pollutant lb/hr grains/dscf (68 degrees F, 29.92 in Hg)

PM10 0.15 0.01. [R307-401-8]

Status: In Compliance. From testing completed May 23 – June 1, 2022, PM10 emissions
were 0.0025 gr/dscf and 0.0225 lb/hr. The source will complete another stack once their
new AO is completed.

II.B.17.i Dunnage Machine (B13): The emissions to the atmosphere from the Dunnage machine baghouse
exhaust stack shall not exceed the following rate and concentration at all times.

Pollutant lb/hr grains/dscf (68 degrees F, 29.92 in Hg)

PM10 0.71 0.01. [R307-401-8]

Status: In Compliance. From testing completed May 23 – June 1, 2022, PM10 emissions
were 0.0007 gr/dscf and 0.043 lb/hr. The source will complete another stack test once their
new AO is completed.

II.B.17.j Compliance Test: Compliance tests are required every two years, subsequent to the initial
compliance test. The Director may require testing or alter the testing schedule at any time.

Notification: The Director shall be notified at least 30 days prior to conducting any required
emission testing. A source test protocol shall be submitted to DAQ when the testing notification
is submitted to the Director.

The source test protocol shall be approved by the Director prior to performing the test(s). The
source test protocol shall outline the proposed test methodologies, stack to be tested, and
procedures to be used. A pretest conference shall be held, if directed by the Director.

Sample Location: The emission point shall be designed to conform to the requirements of 40
CFR 60, Appendix A, Method 1, or other EPA-approved testing method, as acceptable to the
Director. An Occupational Safety and Health Administration (OSHA) or Mine Safety and Health
Administration (MSHA) approved access shall be provided to the test location.

Volumetric Flow Rate: 40 CFR 60, Appendix A, Method 2 or other EPA-approved testing
method, as acceptable to the Director.

PM10: For stacks in which no liquid drops are present, the following methods shall be used: 40
CFR 51, Appendix M, Methods 201, 201a, or other EPA-approved testing method, as acceptable
to the Director. The back half condensable shall also be tested using the method specified by the
Director. All particulate captured shall be considered PM10.

For stacks in which liquid drops are present, methods to eliminate the liquid drops should be
explored. If no reasonable method to eliminate the drops exists, then the following methods shall
be used: 40 CFR 60, Appendix A, Method 5, 5a, 5d, or 5e as appropriate, or other EPA-approved
testing method, as acceptable to the Director. The back half condensable shall also be tested
using the method specified by the Director. The portion of the front half of the catch considered
PM10 shall be based on information in Appendix B of the fifth edition of the EPA document, AP-
42, or other data acceptable to the Director.

The back half condensable shall not be used for compliance demonstration but shall be used for
inventory purposes.

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Calculations: To determine mass emission rates (lb/hr, etc.) the pollutant concentration as
determined by the appropriate methods above shall be multiplied by the volumetric flow rate and
any necessary conversion factors determined by the Director, to give the results in the specified
units of the emission limitation.

For an existing source/emission point, the production rate during all compliance testing shall be
no less than 90% of the maximum production achieved in the previous three (3) years.
[R307-165]

Status: In Compliance. Stack testing was conducted using Method 5 and Method 201a from
May 23 – June 1, 2022. The source notified DAQ prior to testing. Because one stack failed
to pass compliance standards, the source began to work on a new AO, and the stack will be
retested when that new AO is completed.

Section III: APPLICABLE FEDERAL REQUIREMENTS

In addition to the requirements of this AO, all applicable provisions of the following federal programs
have been found to apply to this installation. This AO in no way releases the owner or operator from any
liability for compliance with all other applicable federal, state, and local regulations including UAC
R307.

NSPS (Part 60) IIII: Standards of Performance for Stationary Compression Ignition Internal Combustion
Engines

Status: Not Applicable. The emergency fire engine is not yet operational.

NSPS (Part 60) -OOO: Standards of Performance for Nonmetallic Mineral Processing Plants

Status: Out of Compliance. All stack tests completed in 2022, showed compliance with PM10 standards
except for kettle burner #2. See Condition II.B.17.e for more information. Initial performance testing
for the crusher was completed in 2018 (see DAQC-2018-015956).

MACT (Part 63) -ZZZZ: National Emissions Standards for Hazardous Air Pollutants for Stationary
Reciprocating Internal Combustion Engines

Status: Not Applicable. The emergency fire engine is not yet operational.

AREA SOURCE RULES EVALUATION:

The following Area Source Rules were evaluated during this inspection:

Emission Standards: Sulfur Content of Fuels [R307-203]

Status: In Compliance. The source confirmed that ultra-low sulfur fuel is utilized for mobile off road
equipment. The emergency fire engine is not yet operational.

Emission Standards: Fugitive Emissions and Fugitive Dust [R307-205]

Status: In Compliance. There were no visible fugitive dust emissions observed at the time of
inspection. The source takes steps to minimize fugitive dust by watering haul roads and restricting
the speed of vehicles involved in the operation.

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EMISSION INVENTORY:

Listed before are the Actual Emissions Inventory provided from United States Gypsum Company -
Sigurd Plant. A comparison of the estimated total potential emissions (PTE) on AO:
DAQE-AN106540011-20, dated October 29, 2020, is provided.
PTE are supplied for supplemental purposes only.

Criteria Pollutant PTE tons/yr Actuals tons/yr
Ammonia 1.00 0.34
Carbon Monoxide 47.93 23.99
Nitrogen Oxides 18.16 7.767
Particulate Matter - PM10 34.79 21.31534
Particulate Matter - PM2.5 12.69 7.82451
Sulfur Dioxide 0.19 0.0646
Volatile Organic Compounds 7.75 5.67

Hazardous Air Pollutant PTE lbs/yr Actuals lbs/yr
Formaldehyde (CAS #50000) 2260 1520

PREVIOUS ENFORCEMENT
ACTIONS: The source acknowledged the failure of a stack test for Kettle
burner #2 in a notice to the DAQ on July 8, 2022. An Early
Settlement Agreement was issued on August 9, 2022 (see
DAQC-953-22). The signed ESA was received on September 7,
2022 (see DAQC-1165-22).

COMPLIANCE STATUS &
RECOMMENDATIONS: In regards to Approval Order (AO) DAQE-AN106540011-20,
dated October 29, 2020: In compliance at the time of inspection.
Non-compliance with the emissions for kettle burner #2 were
already addressed. The facility appears to be well-maintained
and operated.

HPV STATUS: Not Applicable.

RECOMMENDATION FOR
NEXT INSPECTION: Inspect at typical frequency for this type of source.

NSR RECOMMENDATIONS: None at this time

ATTACHMENTS: VEO form