EPA-454/R-95-009
SURFACE COAL MINE
STUDY PLAN
Emission Factor And Inventory Group
Emissions, Monitoring, And Analysis Division
Office Of Air Quality Planning And Standards
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
March 1992
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This report has been reviewed by the Office Of Air Quality Planning And Standards, U. S.
Environmental Protection Agency, and has been approved for publication. Any mention of trade
names or commercial products is not intended to constitute endorsement or recommendation for use.
EPA-454/R-95-009
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PREFACE
This report was prepared by Midwest Research Institute under
U.S. Environmental Protection Agency (EPA) Contract No. 68-DO-0137, Work
Assignment Nos. 10 and 68. The principal authors of this report are
Dr. Gregory E. Muleski and Dr. Chatten Cowherd; they were assisted by
Mr. Robert Dobson and Ms. Karen Connery of MRI. Mr. Dennis Shipman and
Mr. Joe Touma of the Office of Air Quality Planning and Standards served as
the EPA's technical monitors of the work assignment.
in
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CONTENTS
Preface H[
Figures vr
Tables • vil
1. Introduction 1
2. Site Selection 7
2.1 Screening activities 7
2.2 Site surveys • 1°
2.3 Final site selection 11
3. Source Air Sampling Methodology 13
3.1 General air sampling equipment
and techniques 15
3.2 Testing procedures 18
3.3 Emission factor calculation procedure 23
4. Ancillary Sample Collection and Analysis 27
4.1 Source material sample collection
and analysis 28
4.2 Control application parameters 36
4.3 Source activity monitoring 38
4.4 Meteorological monitoring 39
4.5 Air quality monitoring 4-2
5. References • 49
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LIST OF FIGURES
Number Pa9e
1 Sampling arrays U, D1, and D2 16
2 Cyclone preseparator 17
3 Two-dimensional sampling array T9
4 Example surface sample data form for unpaved roads 29
5 Example data form for storage piles 32
6 Example moisture analysis form 34
7 Example silt analysis form 37
8 Proposed sampling arrays at a stylized truck-shovel mine.
Filled symbols represent primary sampling locations,
hollow symbols represent saturation samples 47
VI
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LIST OF TABLES
Number Pa9e
1 Summary of "representative" mine attributes 8
2 Emission sources recommended for evaluation 14
3 Quality assurance procedures for sampling media 21
4 Quality assurance procedures for sampling flow rates .... 21
5 Quality assurance procedures for sampling equipment .... 22
6 Criteria for suspending or terminating a test 22
7 PM10 sampling options . • 45
VII
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SECTION 1
INTRODUCTION
At present, ambient paniculate matter (PM-10) impacts from surface
coal mining operations are assessed in the following ways:
1. The mine's operating plan is reviewed to identify major PM-10
emission sources, such as blasting, overburden removal, haul
trucks, etc. The plan is also reviewed to determine source
activity rates—such as tons of coal mined or tons of overburden
removed per year—over the effective life of the mine.
2. An emission factor (mass emitted per unit source activity) is
proposed for each major source. Factors are usually selected
from Section 8.24 of AP-42.1
3. Values from items 1 and 2 above are combined to estimate
annual and worst-case-day PM-10 emission rates from the mine.
4. Dispersion models (such as the Industrial Source Complex [ISC]
, ' model) are then used to simulate the atmospheric transport of
the estimated emissions. Resulting ambient air concentration
estimates are then compared against National Ambient Air
Quality Standards (NAAQSs) or Prevention of Significant
Deterioration (PSD) increments.
The field study described in this report addresses issues involving the
modeling process described above for surface coal mines. Specifically, the
Clean Air Act Amendments (CAAA) require the Administrator to "analyze the
accuracy of. . . models and emission factors and make revisions as may be
necessary to eliminate any significant overprediction." The objectives of this
study are to:
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I. Improve available emission factors for surface coal mines.
II. Develop a comprehensive data base of source activity levels, on-
site meteorological conditions, and air quality data.
III. Conduct a model evaluation study to assess how the current
methodology predicts the ambient air quality impact from mines.
In general terms, the study combines extensive long-term air quality,
source activity, and meteorological monitoring with intensive short-term,
source-directed testing to answer the following types of questions:
• Does the current methodology result in systematic overprediction
of air concentrations?
• How well do ISC model results match measurements in time and
space?
No matter how sophisticated, long-term monitoring of ambient "far-
field" concentrations alone cannot answer questions such as the following:
• What portion or portions of the methodology are most
responsible for overprediction?
• Can the identified portions be modified so that systematic
overprediction is effectively removed?
• What fraction of material emitted at the bottom of the pit
eventually escapes?
To answer these types of questions, the long-term monitoring program
must be supplemented with the intensive short-term monitoring and pit
retention tracer programs that incorporate more source-directed
measurements. Quantitative examination of separate steps in the emission
factor/dispersion model methodology is necessary to answer the "how" and
"why" questions. Furthermore, the particulate tracer studies will provide a
quantitative basis for development of a pit retention algorithm. This report
describes the field study plan designed to meet the above objectives. The
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plan details the sampling methodology, data analysis, and quality assurance
(QA) procedures to be followed.
The principal pollutant of interest in this report is "particulate matter"
(PM), with special emphasis placed on "PM-10"—particulate matter no greater
than 10 jc/mA (microns in aerodynamic diameter). PM-10 is the basis for the
current NAAQSs and thus represents the size range of the greatest regulatory
interest. Nevertheless, formal establishment of PM-10 as the standard basis
is relatively recent, and almost all historical surface coal mine field
measurements reflect a particulate size other than PM-10. Of these, the most
important is "TSP," or Total Suspended Particulate, as measured by the
standard high-volume (hi-vol) air sampler. TSP is a relatively coarse size
fraction and was the basis for the previous NAAQSs and PSD increments.
While the capture characteristics of the hi-vol sampler are dependent upon
approach wind velocity, the effective D50 (i.e., 50% of the particles are
captured and 50% are not) varies roughly from 25 to 50 jumA. To maintain
comparability and compatibility, some field measurements will be referenced
to TSP.
The field sampling program consists of extensive long-term air quality
and meteorological monitoring combined with intensive, short-term source
testing. In addition, pit retention will be studied under a separate set of
experiments. To avoid confusion about what is meant by terms such as
"ambient air" and "near-source," the following defines terms that are used
throughout this document.
• "Source tests" refer to air quality/meteorological measurements made
in the immediate vicinity of an individual emission source (such as a road or
material transfer operation) with the intention of characterizing that source.
Most of these measurements are required for "exposure profiling," which
relies on simultaneous multipoint concentration and wind speed
measurements over the effective cross section of the dust plume to determine
source strength and thus meet Objective I.
"Near-field air monitoring" refers to measurements made further away
than source tests, but still within the vicinity of an individual source. A major
difference is that near-field measurements do not normally span the plume
cross section. Rather, these measurements at a height of 1 to 2 m are
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usually made for comparison with ISC or other model-generated concentration
estimates. Unless otherwise specified, near-field measurements will be made
within the pit.
"Far-field air monitoring" will refer to measurements made at a
considerable downwind distance from the nearest emission source. As such,
these measurements focus on characterizing the air quality impact of the mine
as a whole rather than on any individual source or source category. Unless
specifically stated otherwise, far-field measurements will be made beyond the
rim of the pit (i.e., at surrounding grade). In this document, "ambient" and
"far-field" are equivalent terms. These are the measurements that can be
compared against dispersion model predictions in an overall evaluation of the
current methodology (Objective III).
The remainder of this report is structured as follows: Section 2
describes how candidate test sites will be evaluated and how final sites will
be selected. Section 3 describes the field emissions testing procedures to be
used to develop improved emission factors. Section 4, on the other hand,
describes the collection and analysis of other types of samples—such as
source activity, meteorology, and air quality—that are necessary to reach
objectives of this program. The proposed schedule is provided in Section 5
and references are listed in Section 6.
The sampling and analysis procedures to be followed in this field
testing program are subject to certain quality assurance/quality control
(QA/QC) guidelines. These guidelines are discussed in conjunction with the
activities to which they apply. These procedures meet or exceed the
requirements specified in the reports entitled "Quality Assurance Handbook
for Air Pollution Measurement Systems, Volume II —Ambient Air Specific
Methods" (EPA 600/4-77-027a) and "Ambient Monitoring Guidelines for
Prevention of Significant Deterioration" (EPA 450/2-78-019).
As part of the QC program for this study, routine audits of sampling
and analysis procedures will be performed. The purpose of the audits is to
demonstrate that measurements are made within acceptable control
conditions for paniculate source sampling and to assess the source testing
data for precision and accuracy. Examples of items to be audited include
gravimetric analysis, flow rate calibration, data processing, and emission
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factor calculation. The mandatory use of specially designed reporting forms
for sampling and analysis of data obtained in the field and laboratory aids in
the auditing procedure. Further details on specific sampling and analysis
procedures are provided in the following sections.
The field program represents an excellent opportunity for cooperative
agreements between agency and coal companies/trade groups. A variety of
participation levels are available.
• At a minimum, industry will be asked to provide historical source
activity data, such as production rates and maintenance records
for mine equipment. This information can be treated as "CBI" —
confidential business information.
• Mines may also be asked to supply historical ambient air quality
monitoring and meteorological data.
• With agreement from state and regional offices, minor
modifications to some mine air quality or meteorological
equipment operations may be useful to the study. This could
range from requesting changes in practices (such as different
sampling periods) to the relocation or even loaning of .equipment
for use at another mine during the long-term monitoring program.
• For mines selected that agree to act as test sites, higher levels of
cooperation are possible, ranging from arranging for electrical
power drops and for field laboratory space to providing
technician help who, under direct supervision by the contractors,
would assist in field team support.
Coal company and trade group participation is discussed further in the next
section.
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SECTION 2
SITE SELECTION
Table 1 presents a list of surface coal mine test sites, all of which are
in the Powder River Basin. At the time of this writing, a meeting has been
scheduled between mine and trade association representatives, EPA and
Wyoming Department of Environmental Quality (DEQ) personnel, and MRI.
The meeting will occur on March 5, 1992, in Gillette, Wyoming. As noted in
Table 1, six mines are currently interested in being considered as potential
test sites and will attend the March 5 meeting to learn more about the study.
2.1 SCREENING ACTIVITIES
•-.
The contact person for each candidate mine will participate in one or
two telephone calls during which he/she will be asked to
• Provide an overview of mining operations (truck-shovel versus
dragline, year in mine plan, etc.) and equipment used at the
mine.
• Discuss current and anticipated levels of overburden, topsoil, and
coal-related activities.
• Discuss past and current dust control programs at the mine.
• Provide a plot plan for the mine, showing current areas being
worked and areas planned to be worked in the future,
topography of the mine and surrounding area, locations of any air
quality (AQ) and meteorological ("met") monitors.
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• Describe and, if requested, supply historical emission inventory,
source activity, dispersion modeling analyses, etc. (This woufcf
probably take the form of response to a questionnaire.)
Mine sites will be selected by comparing each candidate mine's
attributes against predetermined criteria of desired location, available data,
site configuration, etc. The criteria given below represent guidelines rather
than "hard and fast" rules. The process of site selection requires many
qualitative and subjective decisions. Candidate mines will be judged on the
following criteria:
• General Location. Although mines with existing PSD monitoring
networks provide ready candidates, most PSD networks are not
necessarily sited to provide the data needed in this study.
Furthermore, mines that are relatively isolated from other mines
would be preferred. While it may not be possible to find
completely isolated mines, those located away from neighboring
mines would be preferred over those in proximity to other mines.
Finally, the site should be isolated from terrain features
influencing local airflows. That is, the terrain immediately
surrounding the mine should be fairly flat.
• Mine Activity. Quantification of the mining activity (traffic
volumes, amount of coal removed, amount of overburden
disturbed, etc.) is needed for the mine model validation effort.
Candidate mines will be judged on the availability of historical
data and on the ease with which these data could be collected
during any field study.
• Logistics. There is a need to locate instruments near
dust-producing activities, at locations up and downwind of the
mine, and at the top of the mine pit highwall. The candidate
mines will be evaluated on the basis of being able to
accommodate the wide variety of sampling locations necessary.
• Representativeness. Preference will be given to mines that are
neither at the start nor near the end of operation according to the
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mine plan. Furthermore, geographic diversity of the test sites is
a desired goal.
Preliminary visits to the mine provide useful overview for the above
items.
2.2 SITE SURVEYS
The site survey is expected to require a 1 - or 2-day visit by two MRI
representatives. At the start of the survey, the mine will provide a short
orientation describing operations. At the mine's discretion, the orientation
can include safety, liability insurance, or other issues. MRI will agree to
requirements made by the mine, such as obeying all posted notices; using
eye, hearing, and other protective equipment; and personnel and vehicle
passes. Also at this meeting, MRI will describe the general sequence of
events anticipated for the testing and will reaffirm its intention to cause
minimal disruption to mine operations.
The remainder of the survey is to be spent visiting and characterizing
potential emission test and monitoring sites in terms of orientation with
respect to prevailing wind direction and pit axis, distance to highwall,
observed level of activity, access to electrical power, proximity to other
emission sources, etc.
For example, near-source measurements of traffic source generally
require long stretches of roads that are approximately perpendicular to the
prevailing wind. In addition, sources should be relatively isolated from other
important PM-10 emission sources within the mine. The following is a list of
example criteria to be applied to a site for roadway source testing.
1. There should be at least 10 m of flat, open terrain downwind of
road.
2. There should be at least 30 m of flat, open terrain upwind of
road.
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3. The height of nearest downwind obstruction should be less than
the distance from the road to the obstruction.
4. The height of nearest upwind obstruction should be less than
one-third the distance from the road to the obstruction.
5. A line drawn perpendicular to the road orientation should form an
angle of 0° to 45° with the mean daytime prevailing wind
direction.
6. The mean daytime wind speed should be greater than 4 mph.
7. The test road should have an adequate number of vehicle passes
per hour enabling completion of a test in no more than 3 h.
8. The traffic mix should be representative of the type of vehicles
that regularly use the road.
Analogous criteria have been established for nonroad sources, such as
material handling operations. These include isolation from other important
sources and wind obstructions, accessibility to the emission source, and
orientation of the source to prevailing winds.
2.3 FINAL SITE SELECTION
' As a result of site visits, it is expected that one or more mines will be
found to be suitable. Those mines will be reevaluated along the selection
criteria lines given above, and a final site will be selected.
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SECTION 3
SOURCE AIR SAMPLING METHODOLOGY
This section describes the procedures to be followed during the
emission source testing portion of the study. A review of emission factors
applicable to surface coal mines has been recently completed.3 This review
also presented recommendations for future source testing, which are
summarized in Table 2. The proposed source testing program focuses on the
following major sources:
• Coal and overburden
• Haul roads
• General traffic (light- and medium-duty)
• Overburden material handling operations
• Coal material handling operations
These sources typically account for 70% or more of particulate emissions at
surface coal mines.4 Similar findings were reported in a recent study of
Wyoming mines.5
" The source-directed field sampling will employ the "exposure profiling"
concept to quantify source emission contributions and near-field
concentrations.
As Table 2 indicates, there are two source types of interest here—
"point" sources (i.e., the material handling operations) and "line" sources (i.e.,
the roadway 'sources). The differences between testing the two types are
described below.
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Table 2. EMISSION SOURCES RECOMMENDED FOR EVALUATION
Line sources (travel-related) to be considered15
1 . Haul trucks
2. General mine traffic
3. Haul trucks (overburden)
"Grouped" approach to material handling emissions0
1 . Overburden removal and placement in trucksd
2. Overburden replacement by draglined
3. Misc. overburden handling operations'1
4. Misc. coal handling operations6
Recommended
number of
tests per
mine8
3-6U, 6-1 2C
3-6U, .6-1 2C
3-6U, 6-1 2C
3-6
3-6
3-6
3-6
Overall
priority
1
3
2
4T
4T
4T
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Notes:
U = uncontrolled, C = controlled. Uncontrolled if not indicated.
Depending on the road network at the mine, it may not be possible to
separate various travel-related emissions. In that case, because of the
importance of travel-related emissions, additional roads or other line sources
(such as scraper travel [see note f below] or road grading) will be tested.
These tests are expected to be of uncontrolled emissions.
Emission factor development will group operations with like materials
• regardless of the equipment involved. This approach is expected to be
particularly beneficial for overburden-related emissions from draglines, power
shovels, truck dumps, etc. It is further expected that test results will be
combined with the generic materials handling emission factor data base.
Dependent upon the type of mine operation (i.e., dragline or shovel/truck).
Including truck dumps, loadout for transit, etc. Again, emission factor
development will group across operations with the same material.
Scrapers in travel mode rated as 7th overall priority.
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3.1 GENERAL AIR SAMPLING EQUIPMENT AND TECHNIQUES
The "exposure profiling" technique for source testing of open
particulate matter sources is based on the isokinetic profiling concept that is
used in conventional (stack) testing. The passage of airborne pollutant
immediately downwind of the source is measured directly by means of
simultaneous multipoint sampling over the cross section of the open dust
source plume. This technique uses a mass flux measurement scheme similar
to EPA Method 5 stack testing rather than requiring indirect emission rate
calculation through the application of generalized atmospheric dispersion
model.
For measurement of particulate emissions from roads, a vertical
network of samplers (Figure 1) is positioned just downwind and upwind from
the edge of the road. (For point sources, a two-dimensional array is needed.)
The downwind distance of 5 m is far enough that interference with sampling
due to traffic-generated turbulence is minimal but close enough to the source
that the vertical plume extent can be adequately characterized with a
maximum sampling height of 5 to 7 m. In a similar manner, the 15-m
distance upwind from the road's edge is far enough from the source that (a)
source turbulence does not affect sampling, and (b) a brief wind reversal
would not substantially impact the upwind samplers. The 15-m distance is,
however, close enough to the road to provide the representative background
concentration values needed to determine the net (i.e., due to the source)
mass flux. As shown in Figure 1, the deployment scheme is expected to use
two independent downwind vertical sampling arrays, D1 and D2. Both
downwind arrays (as well as the upwind array U) make use of high-volume
(hi-vol) air samplers with electronic flow controllers.
The primary air sampling device in this program will be a standard
high-volume air sampler fitted with a cyclone preseparator (Figure 2). The
cyclone exhibits an effective 50% cutoff diameter (D50) of approximately
10 ji/mA when operated at a flow rate of 40 cfm (68 m3/h).
Samplers in the upwind and one of the two downwind arrays are fitted
with the cyclone preseparator to sample PM-10 emissions. During half the
test periods, samplers in the other downwind array will be fitted with cyclone
preseparators; during the other test periods, standard hi-vol roofs will be used
to sample TSP emissions. In this way, one TSP test will be conducted for
every
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three PM-10 tests. TSP measurements provide a useful link to past surface
coal mine emission factor studies.
For the material handling-related "point" sources of PM emission, a
two-dimensional sampling array (Figure 3) is required. The cyclone
preseparator will serve as the primary air sampling device in this array as well.
Note that sampling locations employ colocated cyclone and standard hi-vol
samplers. In this way, a TSP emission factor can be estimated from the
measurement-based PM-10 factor.
Throughout each test, wind speed will be monitored by warm-wire
anemometers (Kurz Model 465) at two heights and the vertical wind speed
profile determined by assuming a logarithmic distribution. An integrating
Biram's vane anemometer, wind odometer, or an equivalent system, will serve
as a backup. Horizontal wind direction will be monitored by a wind vane at a
single height, with 5- to 15-min averages determined electronically prior to
and during the test. The sampling intakes will be adjusted for proper
directional orientation based on the monitored average wind direction.
Additional meteorological equipment may be deployed as part of an air
quality monitoring program. Details are provided in Section 4.
3.2 TESTING PROCEDURES
3.2.1 Preparation of Sample Collection Media
* Particulate samples will be collected on Type AE grade glass fiber
filters. Prior to the initial weighing, the filters will be equilibrated for 24 h at
constant temperature and humidity in a special weighing room. During
weighing, the balance is to be checked at frequent intervals with standard
(Class S) weights to ensure accuracy. The filters will remain in the same
controlled environment for another 24 h, after which a second analyst will
reweigh them as a precision check. If a filter cannot pass audit limits, the
entire lot is to be reweighed. Ten percent of the filters taken to the field will
be used as blanks. The quality
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assurance guidelines pertaining to preparation of sample collection media are
presented in Table 3.
3.2.2 Pretest Procedures/Evaluation of Sampling Conditions
Prior to equipment deployment, a number of decisions will be made as
to the potential for acceptable source testing conditions. These decisions
shall be based on forecast information obtained from the local U.S. Weather
Service office. If conditions are considered acceptable, the sampling
equipment deployment will be initiated. At this time the sampling flow rates
will be set for the various air sampling instruments. The quality control
guidelines governing this activity are found in Table 4.
Once the source testing equipment is set up and the filters inserted, air
sampling will commence. Information is recorded on specially designed
reporting forms and includes:
a. Air samples—Start/stop times, wind speed profiles, flow rates,
and wind direction relative to the roadway perpendicular (5- to
15-min average). See Table 5 for QA procedures.
b. Traffic count by vehicle type and speed.
c. General meteorology—Wind speed, wind direction, and
temperature.
Sampling time will be long enough to provide sufficient particulate
mass and to average over several cycles of the fluctuation in the emission
rate (i.e., vehicle passes on the road). Occasionally sampling may be
interrupted because of the occurrence of unacceptable meteorological
conditions and then restarted when suitable conditions return. Table 6
presents the criteria used for suspending or terminating a source test.
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Table 3. QUALITY ASSURANCE PROCEDURES FOR SAMPLING MEDIA
Activity
Preparation
Conditioning
Weighing
Auditing of weights
Correction for handling
effects
Calibration of balance
QA check/requirement
Inspect and imprint glass fiber media with
identification numbers.
Equilibrate media for 24 h in clean
controlled room with relative humidity of
less than 50% (variation of less than
±5%) and with temperature between 20°
and 25°C (variation of less than ±3%).
Weigh hi-vol filters to nearest 0.1 mg.
Independently verify final weights of 10%
of filters (at least four from each batch).
Reweigh batch if weights of any hi-vol
filters deviate by more than ±2.0 mg. For
tare weights, conduct a 1 00% audit.
Reweigh tare weight of any filters that
deviate by more than ± 1 .0 mg.
Weigh and handle at least one blank for
each 1 to 1 0 filters of each type for each
test.
Balance to be calibrated once per year by
certified manufacturer's representative.
Check prior to each use with laboratory
Class S weights.
Table 4. QUALITY ASSURANCE PROCEDURES FOR
SAMPLING FLOW RATES
Activity
• High volume air samplers
• Orifice and electronic calibrator
QA check/requirement
Calibrate flows in operating ranges
using calibration orifice upon arrival
and every 2 weeks thereafter at
each regional site prior to testing.
Calibrate against displaced volume
test meter annually.
21
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Table 5. QUALITY ASSURANCE PROCEDURES FOR
SAMPLING EQUIPMENT
Activity
Maintenance
• All samplers
Operation
• Timing
• Isokinetic sampling
(cyclones)
• Prevention of static
mode deposition
QA check/requirement8
Check motors, gaskets, timers, and flow
measuring devices at each plant prior to
testing.
Start and stop all downwind samplers during
time span not exceeding 1 min.
Adjust sampling intake orientation whenever
mean wind direction dictates.
Change the cyclone intake nozzle whenever the
mean wind speed approaching the sampler falls
outside of the suggested bounds for that
nozzle. This technique allocates no nozzle for
wind speeds ranging from 0 to 10 mph, and
unique nozzles for four wind speed ranges
above 10 mph.
Cap sampler inlets prior to and immediately
after sampling.
0 All means refer to 5- to 1 5-min averages.
Table 6. CRITERIA FOR SUSPENDING OR TERMINATING A TEST
A test may be suspended or terminated if:a
1. Rainfall ensues during equipment setup or when sampling is in
progress.
2. Mean wind speed during sampling moves outside the 1.3- to 8.9-m/s
(2- to 20-mph) acceptable range for more than 20% of the sampling
time.
3. The angle between mean wind direction and the perpendicular to the
path of the moving point source during sampling exceeds 45 degrees
for two consecutive averaging periods.
4. Daylight is insufficient for safe equipment operation.
5. Source condition deviates from predetermined criteria (e.g., occurrence
of truck spill or accidental water splashing prior to uncontrolled testing).
"Mean" denotes a 5- to 15-min average.
22
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3.2.3 Sample Handling and Analysis
To prevent particulate losses, the exposed media will be carefully
transferred at the end of each run to protective containers for transportation. In
the field laboratory, exposed filters will be placed in individual glassine envelopes
and then into numbered file folders. When exposed filters and the associated
blanks are returned to the MRI laboratory, they will be equilibrated under the
same conditions as the initial weighing. After reweighing, 10% will be audited to
check weighing accuracy.
3.3 EMISSION FACTOR CALCULATION PROCEDURE
To calculate emission rates, a conservation of mass approach is used.
The passage of airborne particulate (i.e., the quantity of emissions per unit of
source activity) is obtained by spatial integration of distributed measurements of
exposure (mass/area) over the effective cross section of the plume. Exposure is
the point value of the flux (mass/area-time) of airborne particulate integrated over
the time of measurement, or equivalently, the net particulate mass passing
through a unit area normal to the mean wind direction during the test. The steps
in the calculation procedure are described below.
3.3.1. Particulate Concentrations
The concentration of particulate matter measured by a sampler is given
by:
Qt
where: C = particulate concentration (u.g/m3)
m = particulate sample weight (mg)
Q = sampler flow rate (m3/min)
t = duration of sampling (min)
23
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To be consistent with the National Ambient Air Quality Standards, all
concentrations and flow rates are expressed in standard conditions (25°C and
101 kPa or 77°F and 29.92 inHg).
The isokinetic flow ratio (IFR) is the ratio of a directional sampler's intake
air speed to the mean wind speed approaching the sampler. It is given by:
aU
where: Q = sampler flow rate (m3/min)
a = intake area of sampler (m2)
U = mean wind speed at height of sampler (m/min)
This ratio is of interest in the sampling of total particulate, since isokinetic
sampling ensures that particles of all sizes are sampled without bias. Note,
however, that because the primary interest in this program is directed to PM10
emissions, sampling under moderately nonisokinetic conditions poses no dif-
ficulty. It is readily agreed that 10 u.m (aerodynamic diameter) and smaller
particles have weak inertial characteristics at normal wind speeds and therefore
are relatively unaffected by anisokinesis.6
• Exposure represents the net passage of mass through a unit area normal
to the direction of plume transport (wind direction) and is calculated by:
E = 10-7 x CUt
where: E = particulate exposure (mg/cm2)
C = net concentration (u.g/m3)
U = approaching wind speed (m/s)
t = duration of sampling (s)
24
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Exposure values vary over the spatial extent of the plume. If exposure is
integrated over the plume effective cross section, then the quantity obtained
represents the total passage of airborne paniculate matter due to the source.
For a line source, a one-dimensional integration is used:
A1 = [" Edh
Jo
where: A1 = integrated exposure (m-mg/cm2)
E = paniculate exposure (mg/cm2)
h = vertical distance coordinate (m)
H = effective extent of plume above ground (m)
For point sources, a two-dimensional integration is used:
JV
H Edhdy
where the quantities are the same as before and
where: A2 = integrated mass (m2-mg/cm2)
W = effective plume width (m)
y = horizontal crosswind coordinate (m)
25
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3.3.2 Particulate Emission Factors
The emission factor for participate generated by vehicular traffic on a
straight road segment expressed in grams of emissions per vehicle-kilometer
traveled (VKT) is given by:
where: e = participate emission factor (g/VKT)
A1 = integrated exposure (m-mg/cm2)
N = number of vehicle passes (dimensionless)
For a point source, the emission factor is found as
where: e = particulate emission factor (g/Mg)
A2 = integrated mass (m2-mg/cm2)
T = mass of material handled (Mg)
26
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SECTION 4
ANCILLARY SAMPLE COLLECTION AND ANALYSIS
This section describes the collection and analysis of samples taken to
complement the air samples described in the last section. These samples
provide information essential to achieving the first two objectives stated in the
Introduction.
• Improve available emission factors.
• Develop a comprehensive data base of source activity levels,
on-site meteorology, and air quality data.
The types of samples and information to be collected fall into the broad
categories of:
• Roadway surface on aggregate material samples.
• Control application parameters.
• Source activity levels.
• Site-specific meteorology.
• Air quality monitoring data.
Each category is described in greater detail below.
27
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4.1 SOURCE MATERIAL SAMPLE COLLECTION AND ANALYSIS
In conjunction with the emissions tests, samples will be taken from the in-
place source material either covering the road surface or being handled as bulk
aggregate (coal, overburden, etc.). These types of samples are needed not only
to evaluate the performance of existing emission factor models but also to
develop improved models.
The following describes the procedures used to collect unpaved road
samples.
1. Ensure that the site offers an unobstructed view of traffic and that
sampling personnel are visible to drivers. If the road is heavily
traveled, use one person to "spot" and route traffic safely around
another person collecting the surface sample (increment).
2. Using string or other suitable markers, mark a 0.3-m (1-ft) width
across the road. (WARNING: Do not mark the collection area with
a chalk line or in anv other method likely to introduce fine material
into the sample.)
3. With a whisk broom and dustpan, remove the loose surface
material from the hard road base. Do not abrade the base during
sweeping. Sweeping should be performed slowly so that fine
surface material is not injected into the air. NOTE: Collect material
only from the portion of the road over which the wheels and
carriages routinely travel (i.e., not from berms or any "mounds"
along the road centerline).
4. Periodically deposit the swept material into a clean, labeled
container of suitable size (such as a metal or plastic 19-L [5-gal]
bucket) with a sealable polyethylene liner. Increments may be
mixed within this container.
5. Record the required information on the sample collection sheet
(Figure 4).
28
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Date Collected
SAMPLING DATA FOR DHPAVED ROADS
Recorded by
Road material (e.g., gravel, slag, dirt, etc.):*
Site of sampling:
METHOD:
1. Sampling device: whisk broom and dustpan
2. Sampling depth: loose surface material (do not abrade road
base)
3. Sample container: bucket with sealable liner
4. Gross sample specifications:
a. Uncontrolled surfaces — 5 kg (10 Ib) to 23 kg (50 Ib)
b. Controlled surfaces — minimum of 400 g (1 Ib) is required
for analysis
Refer to procedure described in Section 2 of "Open Source PM-10
Method Evaluation" for more detailed instructions.
Indicate any deviations from the above:
SAMPLING DATA COLLECTED:
Sample
NO.
Time
Location +
Surf.
Area
Depth
Mass of
Sample
* Indicate and give details if roads are controlled.
+ Use code given on plant or road map for
identification. Indicate sampling location on map.
segment
Figure 4. Example surface sample data form for unpaved roads.
29
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For aggregate materials, the following steps are used to collect a sample.
1. Sketch plan and elevation views of the pile. Indicate if any portion
is inaccessible. Use the sketch to plan where the N increments will
be taken by dividing the perimeter into N-1 roughly equivalent
segments.
a. For a large pile, collect a minimum of 10 increments as near
to the mid-height of the pile as practical.
b. For a small pile, a sample should consist of a minimum of
6 increments evenly distributed among the top, middle, and
bottom.
"Small" or "large" piles, for practical purposes, may be defined as
those piles which can or cannot, respectively, be scaled by a
person carrying a shovel and pail.
2. Collect material with a straight-point shovel or a small garden
spade, and store the increments in a clean, labeled container of
suitable size (such as a metal or plastic 19-L [5-gal] bucket) with a
sealable polyethylene liner. Depending upon the ultimate goals of
the sampling program, choose one of the following procedures:
a. To characterize emissions from material handling operations
at an active pile, take increments from the portions of the pile
which most recently had material added and removed.
Collect the material with a shovel to a depth of 10 to 15 cm
(4 to 6 in). Do not deliberately avoid larger pieces of
aggregate present on the surface.
b. To characterize handling emissions from an inactive pile.
obtain increments of the core material from a 1-m (3-ft) depth
in the pile. A 2-m (6-ft) long sampling tube with a diameter
at least 10 times the diameter of the largest particle being
sampled is recommended for these samples. Note that, for
30
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piles containing large particles, the diameter recommendation
may be impractical.
c. If characterization of wind erosion (rather than material
handling) is the goal of the sampling program, collect the
increments by skimming the surface in an upwards direction.
The depth of the sample should be 2.5 cm (1 in) or the
diameter of the largest particle, whichever is less. Do not
deliberately avoid collecting larger pieces of aggregate
present on the surface.
In most instances, collection method (a) should be selected.
3. Record the required information on the sample collection sheet
(Figure 5). Note the space for deviations from the summarized
method.
For any of the procedures, the sample mass collected should be at least
5 kg (10 Ib). When most materials are sampled with procedures 2.a or 2.b,
10 increments normally result in a sample of at least 23 kg (50 Ib). Note that
storage pile samples usually require splitting to a size more amenable to
laboratory analysis.
. Regardless of origin, material samples undergo the same types of
laboratory analyses. Upon return to MRI's main laboratories, samples undergo
moisture and silt content determination. Moisture content is determined by
weight loss upon oven drying. Silt content refers to the fraction of material
smaller than 200 mesh, as determined by mechanical, dry sieving. The following
steps describe the moisture content determination procedure:
1. Preheat the oven to approximately 110°C (230°F). Record oven
temperature.
2. Record the make, capacity, and smallest division of the scale.
31
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Date Collected
SAMPLING DATA POR STORAGE PILES
Recorded by
Type of material sampled :
Sampling location*
METHOD:
1. Sampling device: pointed shovel (hollow sampling tube if
inactive pile is to be sampled)
2. Sampling depth:
For material handling of active piles: 10-15 cm (4-6 in)
For material handling of inactive piles: 1m (3 ft)
For wind erosion samples: 2.5 cm (1 in) or depth of the
largest particle (whichever is less)
3. Sample container: bucket with a sealable liner
4. Gross sample specifications:
For material handling of active or inactive piles: minimum of
6 increments with total sample weight of 5 kg (10 Ib) [10
increments totalling 23 kg (50 Ib) are recommended]
For wind erosion samples: Minimum of 6 increments with total
sample weight of 5 kg (10 Ib)
Refer to procedure described in Section 4 of "Open Source PM-10
Method Evaluation" for more detailed instructions.
Indicate any deviations from the above:
SAMPLING DATA COLLECTED:
Sample
No.
Time
Location* of
Sample Collection
Device
Used
S/T **
Depth
Mass
of Sample
* Use code given on plant or area map for pile/sample
identification. Indicate each sampling location on .map.
Figure 5. Example data form for storage piles.
32
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3. Weigh the empty laboratory sample containers which will be placed
in the oven to determine their tare weight. Weigh containers with
the lids on if they have lids. Record the tare weight(s). Check zero
before each weighing.
4. Weigh the laboratory sample(s) in the container(s). For materials
with high moisture content, ensure that any standing moisture is
included in the laboratory sample container. Record the combined
weight(s). Check zero before each weighing.
5. Place sample in oven and dry overnight. Materials composed of
hydrated minerals or organic material like coal and certain soils
should be dried for only 114 h.
6. Remove sample container from oven and (a) weigh immediately if
uncovered, being careful of the hot container; or (b) place the
tight-fitting lid on the container and let cool before weighing.
Record the combined sample and container weight(s). Check zero
reading on the balance before weighing.
7. Calculate the moisture as the initial weight of the sample and
container minus the oven-dried weight of the sample and container
divided by the initial weight of the sample alone. Record the value.
8. Calculate the sample weight to be used in the silt analysis as the
oven-dried weight of the sample and container minus the weight of
the container. Record the value. (See Figure 6.)
The oven-dried sample then undergoes silt analysis:
1. Select the appropriate 20-cm (8-in) diameter, 5-cm (2-in) deep
sieve sizes. Recommended U.S. Standard Series sizes are 3/8 in,
No. 4, No. 40, No. 100, No. 140, No. 200, and a pan. Comparable
Tyler Series sizes can also be utilized. The No. 20 and the
No. 200 are mandatory. The others can be varied if the
recommended sieves are not available or if buildup on one
33
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MOISTURE ANALYSIS
Date: By:
Sample No: Oven Temperature:
Material: Date In __ Date Out
Time In ' Time Out,
Split Sample Balance: Drying Time
Make
Capacity Sample Weight (after drying)
Smallest Division Pan + Sample:
Pan: '
Total Sample Weight: Dry Sample:
(Excl. Container)
Number of Splits: MOISTURE CONTENT:
(A) Wet Sample Wt
Split Sample Weight (before drying) (B) Dry Sample Wt
Pan + Sample: ' (C) Difference Wt
Figure 6. Example moisture analysis form.
34
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participate sieve during sieving indicates that an intermediate sieve
should be inserted.
2. Obtain a mechanical sieving device such as vibratory shaker or a
Roto-Tap without the tapping function.
3. Clean the sieves with compressed air and/or a soft brush. Material
lodged in the sieve openings or adhering to the sides of the sieve
should be removed (if possible) without handling the screen
roughly.
4. Obtain a scale (capacity of at least 1,600 g or 3.5 Ib) and record
make, capacity, smallest division, date of last calibration, and
accuracy.
5. Weigh the sieves and pan to determine tare weights. Check the
zero before every weighing. Record weights.
6. After nesting the sieves in decreasing order with pan at the bottom,
dump dried laboratory sample (preferably immediately after
moisture analysis) into the top sieve. The sample should weigh
between ~ 400 and 1,600 g (0.9 to 3.5 Ib). This amount will vary
for finely textured materials; 100 to 300 g may be sufficient with
90% of the sample passing a No. 8 (2.36 mm) sieve. Brush fine
material adhering to the sides of the container into the top sieve,
and cover the top sieve with a special lid normally purchased with
the pan.
7. Place nested sieves into the mechanical sieving device and sieve
for 10 min. Remove pan containing minus No. 200 and weigh.
Repeat the sieving in 10-min intervals until the difference between
two successive pan sample weighings (where the tare weight of the
pan has been subtracted) is less than 3.0%. Do not sieve longer
than 40 min.
35
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8. Weigh each sieve and its contents and record the weight. Check
the zero reading on the balance before every weighing.
9. Collect the laboratory sample and place the sample in a separate
container if further analysis is expected.
10. Calculate the percent of mass less than the 200 mesh screen
(75 u.m). This is the silt content. See Figure 7.
4.2 CONTROL APPLICATION PARAMETERS
It is expected that the test mine will have an unpaved road dust control
program in place. Example programs include wet suppression by water truck or
"rainbird" system, or chemical treatment from periodic applications of petroleum
resins, acrylics, asphalt emulsions, or other commercially available products. It is
important that any emission test conducted of a controlled road (or of a
controlled material-handling operation, for that matter) be associated with an
adequate description of the control measure.
For unpaved roads treated chemically, this would include a history of
control applications, with "intensity" (as measured by the volume of solution
applied per unit area of road surface), the dilution ratio, and the date of each
application recorded. Analogous (but less detailed) information is needed for an
unpaved watering program. Finally, for wet suppression of handling emissions,
flow rates and nozzle types need to be identified. MRI will work closely with
mine personnel to obtain the above types of information.
To measure the application intensity of water or chemical suppressants,
MRI will place tared sampling pans at various locations on the test strips prior to
application. Special attention is to be paid to the problem associated with the
chemical dust suppressant splashing off the bottom of the pan. To reduce this
potential source of error, an absorbent material will be used to line the bottom of
the pan. Once the control is applied, the sample pans will be reweighed and the
density of the solution will be measured. The application intensity measured by
each pan is given by
36
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SILT ANALYSIS
Date
Sample No:
Material:
Split Sample Balance:
Make
Capacity
Smallest Division
By
Sample Weight (after drying)
Pan + Sample: .
Pan:
Dry Sample:.
Final Weight:
e/ o?u Net Weioht <200 Me«h ..-.-
%SlIt- Total Net Weight X1°°
SIEVING
nme: Start:
Weiant (Pan Only)
Initial
20 mm:
30 min:
40 mm:
Screen
3/8 in.
Tare Weight
(Screen)
4 mesh I
1 0 mesh
20 jnesh
40 mesh
100 mesh
140 mesh
200 mesh
Pan
Final Weight
(Screen + Sample)
I
Net Weight (Sample)
%
Figure 7. Example silt analysis form.
37
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where: a = application intensity (volume/area)
m, = final weight of the pan and solution (mass)
m, = tare weight of the pan (mass)
p = weight density of solution (mass/volume)
A = area of the pan (area)
The individual application intensities obtained will be examined to determine any
significant spatial variations and to obtain an average value.
Note that the performance of unpaved road dust controls is strongly
dependent upon not only the service environment (such as the weight and
number of vehicles traveling the road after control application) but also ambient
meteorological conditions (such as temperature, insolation, and freeze/thaw
cycles). Service environment factors are described in the next section, while
on-site meteorology is discussed in Section 4.4.
4.3 SOURCE ACTIVITY MONITORING
• One potentially significant difference from the study described here and
past field studies at surface coal mines is the development of a "source activity
data base." As noted earlier, the impact of PM10 emissions from SCMs is
typically based on annual averages (of coal production, etc.) presented in a
mine's operating plan or obtained from an active mine. Worst-case emissions
are usually calculated under the assumptions (a) that natural moisture mitigation
is negligible and (b) that the worst-case emissions from all sources under
consideration occur at the same time. Worst-case activity levels are often scaled
from the annual average by an assumed factor (such as a factor of 2).
In contract to this approach, a 'dynamic11 emissions inventory will be
obtained to accomplish the goals of this program. Unlike most regulatory
modeling exercises, which are interested in "annual average" or "worst-case"
38
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conditions, this program will track actual source activity over time. Source
activity levels will be recorded during the entire period'that field test crews are
present at surface coal mines.
Source extent activity data will be collected with a variety of tools. For
example, in addition to visual observation and note taking, video cameras and/or
time-lapse photography may be used to determine activity on roads or at other
mining sources. For roads and other travel-related sources (such as coal or
overburden truck dumps), pneumatic axle counters will be used to supplement
other approaches.
This monitoring activity will make use of pneumatic and other types of
traffic counters; these can be removed for road grading, etc. The monitoring also
calls for some videotaping, requiring two or three enclosed or sheltered areas in
which to set up equipment. The areas should have standard AC power and be
relatively clean and secure. At present it is anticipated that approximately three
to six pneumatic counters and two to three video cameras will be able to provide
the necessary information for the major emission sources.
The use of a variety of data acquisition methods aids in resolving source
activity levels on an appropriate temporal basis. Source activity (both rate and
physical location) will be resolved to 4-h or shorter time periods. The 4-h period
corresponds to one-half work shift at a mine. It is likely that most emission
sources at a surface mine can be viewed as relatively constant in time and
space over a work shift. The use of a half-shift as the basic time averaging unit
provides a margin of safety. In addition, at the start of each day, the field crew
chief will ask the mine superintendent or his designee to describe any unusual
events (equipment downtime, etc.) during the past 24 h.
4.4 METEOROLOGICAL MONITORING
The collection of valid, applicable meteorological data is essential in
meeting the objectives of the proposed program. These data must be repre-
sentative of atmospheric dispersion conditions at the source and at locations
where the source may have a significant impact on air quality or where air quality
39
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is monitored. The representativeness of the data is dependent upon (1) the
proximity of the meteorological monitoring site to the area under consideration,
(2) the complexity of the topography of the area, (3) the exposure of the
meteorological sensors, and (4) the period of time during which the data are
collected.
According to the EPA's PSD guidelines, a data base representative of the
meteorological monitoring site should consist of at least the following data:
1. Hourly average wind speed and direction.
2. Hourly average atmospheric stability based on Pasquill stability
category or wind fluctuations (09), or vertical temperature gradient
combined with wind speed.
3. Hourly surface temperature at standard height for climatological
comparisons and plume rise calculations.
4. Hourly precipitation amounts for climatological comparisons.
Mines agreeing to serve as test sites may already have active PSD-type
meteorological monitoring programs. The suitability of any existing meteoro-
logical monitoring network will be reexamined once a mine has been selected as
a field test site. In any event, at least a backup meteorological monitoring station
will be deployed during this field program.
As with the particulate monitoring sites to be discussed in Section 4.5, it is
essential to ensure that microscale source, topographic, and meteorological
influences do not bias the data obtained with the weather station. This
consideration is critical because of the generally large areas which are to be
represented by the station.
Following PSD guidelines, the wind monitor should be sited:
1. To monitor representative wind field.
40
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2. Near the source of particulates.
3. Away from undesired microscale flows.
4. Away from the influence of trees and obstructions (at a distance
from an obstacle approximately five times the obstacle's height).
5. At a height of 10 m.
6. Adjacent to particulate sampler if possible.
Analogously, the ambient temperature sensor must be protected against
thermal radiation from the sun, sky, earth, and any surrounding objects and must
be adequately ventilated. The temperature sensor suggested for this study is
housed on the meteorological mast just below the wind sensors and is protected
by a radiation shield.
The rain gauge used in the study should be located at ground level in a
sheltered area to prevent undue effects from atmospheric turbulence. Ideally,
the gauge site should be carefully leveled and protected in all directions by
objects of uniform height (trees, buildings, etc.). If this cannot be accomplished,
an effort should be made to site the instrument where it will be shielded from up-
and down-valley flows. The heights of the surrounding objects should be
between one-half and one times their distance from the gauge.
Because no site surveys have been done at the time of this writing, it is
not now possible to completely define what meteorological monitoring equipment
will be employed. The following discussion represents a "best guess" at this
time.
At present it is anticipated that each "primary" air quality monitoring station
(as defined in Section 4.5) will be equipped with at least a recording
meteorological station, such as Meteorology Research Inc. Model 1077 or a
Climatronics bi-vane weather station. Because the bi-vane unit stores digitized
data, it would serve as the principal monitoring device. The Climatronics unit is
41
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capable of providing a good indication of hourly gauge atmospheric stability class
as well as hourly wind speed and direction.
The Model 1077 weather station, on the other hand, has been proven to
be a reliable field monitor for wind speed and direction, temperature, and
windfall. This reliability makes the Model 1077 a good backup system. To be
sure, much of the reliability is due to the fact that a strip chart is used to record
data. The choice of recording device, however, makes the estimation of stability
class more tenuous. In short, the standard deviation of azimuth wind direction is
estimated by a procedure developed by Markee.7
where: a0 = standard deviation of wind direction
R0 = hourly range of wind direction
The quantity a0 is then used to convert to the stability class as follows:
Pasquill stability
class
> 22.5 A
17.5 - 22.5 B
12.5 - 17.5 C
7.5 - 12.5 D
3.8 - 7,5 E
<3.8 F
4.5 AIR QUALITY MONITORING
Present discussions indicate that a model evaluation may be performed at
a surface coal mine in later years. As such, some results from this study may be
42
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used in that field evaluation. The following paragraphs describe the type of field
program anticipated at a later date.
As was the case for meteorological monitoring, it is likely that mines
selected as field test sites will have active PSD-type air quality monitoring
programs. Unlike the meteorological stations, however, it is improbable that
existing air quality monitoring networks will prove entirely suitable for model
evaluation purposes. For this reason, a flexible air quality monitoring program
has been included as part of this field program.
Like the source activity monitoring, the air quality monitoring program will
differ from past studies in that finer time resolution is of interest. Past studies
have generally had to "make do" with available data. Nevertheless, the time
period over which ambient measurements are made, over which emission rates
are computed, and over which source locations are idealized should be as short
as practicable. The performance of an air quality model should improve when
the input data have finer resolution. Nevertheless, any analysis of a model's
performance in predicting PM10 concentrations must consider 24-h time intervals
because many mines have more difficulty demonstrating compliance with 24-h
rather than annual increments or standards.
Various time averaging periods are possible for PM10 concentrations. In
the regulatory sense, 24-h concentrations are m<••£• important because the
NAAQSs and PSD increments are based on tha; me period. On the other
hand, currently available dispersion models typic.; *y use hourly meteorological
data to predict hourly concentrations. The hourly predictions are then combined
to provide longer-period averages.
Until recently, ambient PM10 concentrations could only be sampled by
reference methods for periods on the order of 24 h. Within the past year,
several equivalent PM10 measurement methods have become available, providing
far greater time resolution than the older high-volume sampling methods.
Table 7 summarizes the advantages and disadvantages of various field sampling
equipment that could be used.
43
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If a network consisting of only continuous PM10 monitors were to be
established, concentration at each monitoring location can be averaged on a 1-h
basis. Although these monitors provide the finest time resolution possible, they
typically require temperature-controlled enclosures and "clean" electric power.
The enclosure and power requirements accentuate the high purchase cost of
continuous samplers. In summary, continuous monitors provide a very high
degree of temporal resolution but can provide adequate spatial coverage only at
a very high level of cost.
The present field program, however, seeks to combine the best features of
the available PM10 sampling methods by combining two or three continuous
monitors with 6 to 10 high-volume samplers and with 10 to 20 "saturation"
samplers. In this way, a high degree of temporal resolution is accomplished at a
few locations within a generally well-monitored geographic area.
This combination is viewed as providing the greatest spatial coverage
possible at a reasonable cost while still providing the type of data needed to
assess the scientific component of the dispersion model. Specifically, the
following types of equipment are proposed for the study.
1. Two or three primary monitoring stations, each station with:
a. A continuous PM10 monitor such as a beta gauge or tapered
element oscillating microbalance.
b. At least one each Andersen size-selective-inlet (SSI) and
Wedding PM10 inlet mounted on a high-volume sampler.
c. At least one saturation sampler.
d. A recording meteorological station.
The different samplers will be colocated. Furthermore, the "whole-
air" (i.e., noncontinuous) samplers will be operated over the same
time periods. If only one set of high-volume samplers is available,
then they will be operated on a 24-h schedule. If more than one of
44
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45
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each type is available, then shorter periods (such as 8 and 12 h)
are recommended.
Each of the primary sampling locations will be equipped with a
trailer and either a power drop or a heavy-duty diesel generator to
provide the "clean8 electrical power needed to operate the
continuous monitors. (If generators are used, special precautions
will be taken to avoid sample contamination by exhaust.)
2. Approximately 10 to 20 saturation samplers deployed throughout
the geographic area downwind of the mine.
The siting of air quality monitoring devices is highly dependent upon the
characteristics of the test site, factors such as the distances and orientation of
major PM10 sources, prevailing wind directions, mines, and surrounding
topography. Because site surveys have yet to be conducted, monitor siting can
only be discussed in general terms. For illustration purposes, a hypothetical
power shovel mine will be used as an example (see Figure 8).
At the example mine, the major sources are found to be coal haul trucks,
overburden haul trucks, overburden handling, and overburden dumping. General
traffic is also important but is confined to the two roads shown in the figure.
• Mining activity rates and locations at the example mine have been
evaluated along with the site-specific meteorological data to determine prevailing
wind direction and the sampler locations. It is proposed that at least three
portable samplers be placed in an arc immediately downwind of the major
sources.
Significant mining emission sources are rarely grouped together; rather the
sources may be spread over distances on the order of miles. To measure the
cumulative effect of separate sources, the model should be tested at not only the
points of maximum concentration from individual sources but also at points
where the combined effect is greatest. A second set of samplers is placed at the
points where emissions from individual sources combine to produce a secondary
maximum (see Figure 8), To determine what the background contribution is,
46
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TOPSOIL REMOVAL
COAL BLASTING
AND LOADING
PREVAILING WIND
DIRECTION
OVERBURDEN
BLASTING AND LOADING
OVERBURDEN DUMPING
TOPSOIL REPLACEMENT
OVERBURDEN
HAUL ROAD
o
o
COAL HAUL- ROAD
COAL
PROCESSING
Maximum concentration samplers (assumes four largest PM-10 sources are the two roads,
overburden blasting/loading, and overburden dumping
Cumulative concentration samplers
Q Upwind/background concentration samplers
Figure 8. Proposed sampling arrays at a stylized truck-shovel mine. Filled
symbols represent primary sampling locations, hollow symbols
represent saturation samples.
47
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three additional locations are proposed, placed in upwind and crosswind
directions from the mining activities. Roughly half of the saturation PM10
samplers will be sited to sample combined concentrations.
The exact placement of samplers at the actual mines tested will be a
function of both the configuration of the mine and the local meteorology. Until
the time that an actual test site is decided upon, exact placement of samplers
cannot be made.
48
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SECTION 5
REFERENCES
1. U.S. Environmental Protection Agency, Compilation of Air Pollutant
Emission Factors (AP-42), Research Triangle Park, North Carolina,
September 1985.
2. Shearer, D. L, R. A. Dougherty, C. C. Easterbrook, Coal Mining Emission
Factor Development and Modeling Study, TRC Environmental
Consultants, July 1981.
3. Muleski, G. E., Review of Surface Coal Mining Emission Factors, EPA
Contract No. 68-DO-0137, Assignment 10, July 1991.
4. Cole, C. F., B. L. Murphy, J. S. Evans, A. Gards, Quantification of
Uncertainties in EPA's Fugitive Emissions and Modeling Methodologies at
Surface Coal Mines, TRC Environmental Consultants, February 1985.
5. Vardiman, S., and K. Winges, Powder River Basin Model Validation
Analysis, TRC report prepared for Wyoming Department of Environmental
Quality, August 1991.
6. Davies, C. N., "The Entry of Aerosols in Sampling Heads and Tubes,"
British Journal of Applied Physics, 2:921, 1968.
7. Markee, E. H., Jr., "On the Relationships of Range to Standard Deviation
of Wind Fluctuations," Monthly Weather Review, 91(2), pp. 83-87, 1963.
49
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TECHNICAL REPORT DATA
fflease read Instructions on the reverse before completing!
EPA-454/R95-009
3. R£C/Pf£NT'S ACCESSION A/O,
4. TITLE AND SUBTITLE
Surface Coal Mine Study Plan
5. REPORT DATE
March 4, 1992
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
g.^EHFORMINGJORGANIZATlptiLNAME AND ADDRESS
Emission Tactor ancT Inventory TJroup ,
Emissions Monitoring and Analysis Division
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park. NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report outlines the test protocols and plans to be used for improving emission
factors for western surface coal mines in response to the requirements of Section
234 of the Clean Air Act of 1990.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report/
21. NO. Ol
53
20. SECURITY CLASS (This page)
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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