PROJECT SUMMARY
IMPROVED EMISSION FACTORS FOR FUGITIVE DUST
FROM WESTERN SURFACE COAL MINING SOURCES
by
Kenneth Axetell, Jr.
PEDCo Environmental, Inc.
2620 Pershing Road
Kansas City, MO 64108
and
Chatten Cowherd, Jr.
Midwest Research Institute
425 Volker Boulevard
Kansas City, MO 64110
Contract No. 68-03-2924
Work Directive No. 1
Project Officers
Jonathan G. Herrmann
Energy Pollution Control Division
Industrial Environmental Research Laboratory
Cincinnati, OH 45268
and
Thompson G. Pace, P.E.
Monitoring and Data Analysis Division
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
This study was conducted in cooperation with
the U.S. Environmental Protection Agency
Region VIII Office in Denver, CO, and the
Office of Surface Mining in Washington, D.C.,
and Denver, CO.
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
October 1983

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PROJECT SUMMARY
IMPROVED EMISSION FACTORS FUR FUGITIVE DUST
FROM WESTER SURFACE COAL MINING SOURCES
The primary purpose of this study was to develop emission factors for
significant surface coal mining operations that would be applicable at Western
surface coal mines and would be based on widely acceptable, state-of-the-art
sampling and data analysis procedures. The approach was to develop emission
factors for individual mining operations in the form of equations with correc-
tion factors to account for site-specific conditions. Factors were determined
for three particle size ranges—less than 2.5«om (fine particulate), less than
15 pm. (inhalable particulate), and total suspended particulate.
A total of 265 tests were run at three mines during 1979 and 1980. The
following sources were sampled: Drilling (overburden), blasting (coal and
overburden), coal loading, bulldozing (coal and overburden), dragline opera-
tions, haul trucks, light- and medium-duty vehicles, scrapers, graders, and
wind erosion of exposed areas and coal storage piles. The primary sampling
method was exposure profiling; however, upwind-downwind, balloon, wind tunnel,
and quasi-stack sampling methods were used on sources unsuitable for exposure
profiling.
Several variables that might affect emission rates, such as vehicle
speed, were monitored during the tests. Significant correction parameters in
the emission factor equations were then determined by multiple linear regres-
sion analysis. Confidence Intervals were also calculated for each of the
factors.
Data for determination of deposition rates were obtained, but scatter in
the data prevented the development ol an algorithm. Control efficiencies for
two unpaved road control measures were estimated.
The report concludes with a comparison of the generated emission factors
with previous factors, a statement regarding their applicability to mining
operations, and recommendations for additional research in Western and other
mines.
This publication is a summary of the complete project report, which can
be purchased from the National Technical Information Service.
INTRODUCTION
Figure 1 is a schematic of operations at a typical Western surface coal
mine. These operations vary somewhat from mine to mine, and the relative
amounts of dust produced by the different operations will vary greatly from
mine to mine. A ranking of the sources was performed to determine which were
significant particulate sources that warranted sampling, based on average mine
conditions. The most significant dust-producing operations are shown in Table
1.
1

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Sampling Program
The Dumber of mines to be surveyed was set at three—a compromise between
sampling over the widest range of mining/meteorological conditions by visiting
a large number of mines and obtaining the most tests within the given budget
and time limits by sampling at only a few mines. The three mines selected
were in diverse geographic areas in the Western coal fields having the largest
strippable reserves: Fort Union (North Dakota), Powder River Basin (Montana-
Wyoming), and San Juan River (New Mexico-Arizona). These mines had most of
the significant dust-repoduclng operations, and most operations could be sampled
at more than one location in each mine. While sampling was limited to several
weeks at each mine, seasonal variations in emission rates were considered by
sampling during three of four seasons.
A total of 265 tests (245 of them on uncontrolled sources) were conducted
during four sampling periods. Table 1 summarized the tests by mine and by
source. The total number of samples required for each source to achieve a 25
percent relative error at a 20 percent risk level was determined statisti-
cally. The calculated sample size could not be obtained from some sources
because of difficulties encountered In the field, such as source inactivity,
Inability to place the sampling array in the required location due to topo-
graphical barriers, unstable wind directions, and low or high windspeeds. A
major effort was made to obtain a statistically adequate sample size for haul
trucks, the major dust-producing source.
Sampling Techniques
A thorough review of possible fugtive dust sampling techniques Indicated
that no one technique was adequate to sample all sources. Exposure profiling,
designated as the preferred technique, was used whenever possible (63 profiling
tests were performed). Each of the five different sampling techniques used in
the study is described briefly in the following paragraphs.
The exposure profiler consisted of a portable tower (4 to 6 m in height)
supporting an array of sampling heads. Each sampling head was operated as an
isokinetic exposure sampler. The air-flow stream passed through a settling
chamber that trapped particles larger than about 50 ;um, and then flowed upward
through a horizontally position, standard 8 x 10 in. glass fiber filter.
Sampling intakes were positioned directly Into the wind, and sampling veloci-
ties were adjusted to match the mean wlndspeed at each height (as determined
immediately prior to the test). Wlndspeed was monitored by hot-wire anemo-
meters throughout the test, and flow rates were adjusted for major changes in
mean wlndspeed. Operating concurrently with the profiler, dichotomous samplers
placed at two heights on the tower determined particle size distribution.
Duplicate dustfall buckets located at the profiler and 20 and 50 m downwind of
the source provided information on deposition.
The exposure profiler concept was modified for sampling blasting opera-
tions. The large horizontal and vertical dimensions of the blast plumes
required a suspended array of samplers as well as ground-based samplers in
order to sample over the plume cross-section In both dimensions. Five 47-mm
polyvinyl chloride (PVC) filter heads and sampling orifices were attached to a
line suspended from a tethered balloon. The samplers were located at different
2

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TO PREPARATION
AND SHIPPING
FACILITIES
Y>t\VDRILLED OVERBUWE*
*V. BLASTED OVERBURDEN
BENCH! N
EXPOSED COAL
kk
Jt UNO! STUBBED Jk
DRILLED COAL
Blasted coal
coal LOADING
TOPSOIL L0A01NG
HAUL ROAD
Figure 1. Operations at typical Western surface coal mines.
3

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TABLE 1. SUMMARY OF TESTS PERFORMED
Source
Sampling
technique
Mine 1
Mine 2
Mine 1W*
Mine 3
Total
Drilling, ovb.b
Quasi-stack
11
-
12
7
30
Blasting, coal
Balloon
3
6

7
16
Blasting, ovb.
Balloon
2


3
5
Coal loading
(shovel/truck or
front-end loader)
liw-dwc
2
8

15
25
Bulldozing, ovb.
Uw-dw
4
7

4
15
Bulldozing, coal
Uw-dw
4
3

5
12
Dragli ne
Uw-dw
6
5

8
19
Haul trucks
Profiling
7d
9
01
o
9
35
Light- and
medium-duty trucks
Profiling
5
5

3
13
Scrapers
Profiling
5d
6
2
2
15
Graders
Profiling

5

2
7
Exposed area, ovb.
Wind tunnel
11
14
3
6
34
Exposed area, coal
Wind tunnel
10
7
6
16
39
Total
70
75
33
87
265
. Winter sampling period.
ovb. = overburden
j Uv-dw = upwind-downwind
Five of these tests were comparability tests (profiling and upwind-downwind).
Six of these tests were done by upwind-downwind.
4

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heights (2.5, 7.6, 15.2, 22.9, and 30.5 m), and each sampler was attached to a
wind vane so that the orifices would face directly Into the wind. The samplers
were connected to a ground-based pump with flexible tubing. The pump maintained
an isokinetic flow rate for a windspeed of 5 nph. To avoid equipment damage
from blast debris and to obtain a representative sample of the plume, the
balloon-suspended samplers were located about 100 m downwind of the blast
area. The balloon-supported samplers were supplemented with five hl-vol/
dlchotomous sampler pairs spaced 20 m apart and located on an arc at the same
distance as the balloon from the edge of the blast area.
The upwlnd-dovnwlnd array used for sampling point sources Included 15
samplers (10 hl-vol and 5 dlchotomous). One of each sampler type was located
upwind of any dust from the source. Initially, downwind samplers were placed
at nominal distances of 30, 60, 100, and 200 m; however, these distances had
to be frequently modified because of physical obstructions (e.g., highwall) or
potential Interfering sources. Two samplers of each type were placed at a
distance of 30 m, three hl-vols and two dlchotomous samplers at 60 m, three
hi-vola at 100 m, and one hl-vol at 200 m. Both sampler types were mounted on
tripod stands at*a height of 2.5 m, the highest manageable height for this
type of rapid-mount stand. The downwind array was modified slightly for
sampling line sources. It consisted of two pairs of hi-vol/dlchotomous samplers
at 5, 20, and 50 m and two hl-vols at 100 m. The two rows of samplers were
separated by 20 m. The upwind-downwind method allowed Indirect measurement of
deposition through calculation of apparent emission rates at a series of
downwind distances.
A portable wind tunnel consisting of an inlet section, a test section,
and an outlet diffuser was used to measure dust emissions generated by wind
erosion of exposed areas and storage piles. The test section has a 1 by 1 ft
cross section so it could be used with rough surfaces. The open-floored test
section was placed directly on the 1 by 8 ft surface to be tested, and the
tunnel air flow was adjusted to predeterminei values that corresponded to the
means of N0AA windspeed ranges. Tunnel windspeed was measured by a pitot tube
at the downstream end of the test section and related to windspeed at the
standard 10 m height by means of a logarithmic profile. An emission-sampling
module was located between the tunnel outlet and the fan inlet to measure
partlcualte emissions generated in the test section. The sampling trains,
which was operated at 15 to 25 ft^/mln, consisted of a tapered probe, cyclone
precollector, parrallel-slot cascade impactor, backup filter, and hl-vol motor.
Interchangeable probe tips were sized for isokinetic sampling over the desired
tunnel windspeed range.
For quasl-stack sampling of overburden drilling, a wooden enclosure with
4 by 6 ft end openings was fabricated in the field. During each test, the
enclosure was placed adjacent to, and downwind of the drill platform. The cross
section of the enclosure was divided into four rectangeles of equal area, and a
hot-wire anemometer measured wind velocity at the center of each rectangle.
Four exposure prifiler samplers with remote flow controllers were used to
sample In the four enclosure subareas. Sampler flow rates were adjusted at 2-
to 3-minute Intervals to near-isoklnetlc conditions with the windspeed measure-
ments. This sampling technique did not measure particle size distribution of
deposition.
5

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Source Characterization
Many independent variables influence particulate emission rates from
mining sources. If these variables are to be quantified and Included as
parameters (correction factors) in the emission factor equations, suspected
variables must be measured for each emission test. Table 2 presents the
parameters monitored for each source.
SUMMARY OF RESULTS
Total suspended particulate (TSP) and inhalable particulate (IP) emission
rates are presented in Table 3. For some sources, the number of test values
Is lover than the number of tests reported in Table 1. This indicated elimina-
tion of data after a test was completed. For example, the plume may have
missed the sampling array for most of the period or the sampler may have mal-
functioned. Most of the tests for which no data are presented in Table 3
(36 out of 44) were run on exposed areas. These tests were unproductive
because eroding particles could not be generated on the test surfaces, even at
the highest vlndspeed simulated In the wind tunnel.
The geometric mean values in Table 3 are not emission factors; no considera-
tion has been given to correction factors at this point.
The relative standard deviations of emission rates by individual sources
ranged from 0.7 to 1.5. Relative standard deviation is a measure of sample
variation. For most sources with at least 10 data points, emission rates
varied more than two orders of magnitude; however, similar variations were
noted in independent variables thought to have an effect on emission rates.
Multiple Linear Regression Analysis
The method for developing correction factors was based on multiple linear
regression (MLR). Briefly, values for all variables being considered as
possible correction factors were first tabulated by source along with the
corresponding TSP emission rates for each test. The data were than trans-
formed to their natural logarithms (In) because a preliminary analysis had
indicated the emission rates were lognormally rather than normally distributed.
The transformed data were applied to the MLR program, speciflylng the stepwise
option and permitting entry of all variables that increased the multiple
regression coefficient.
Wind Erosion Sources
The emission rates reported In Table 3 for wind erosion from coal pile
surfaces and exposed ground areas were obtained by testing several naturally
occurring surfaces at successively increasing vlndspeeds simulated in the wind
tunnel. Analysis of SF (the size fraction less than 30>um) and IP emission
rates Indicated that the rates (1) Increased with windspeed above a threshold
level on newly exposed surfaces and (2) decreased sharply with time after the
onset of erosion.
Threshold velocities for detectable movement of surface particles were
unexpectedly high. This was attributed to the presence of natural crusts on
6

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TABLE 2. SOURCE CHARACTERIZATION PARAMETERS MONITORED DURING TESTING
Source
Parameter"
Quantification technique
All tests®
Wind speed and direction
Anemometer

Temperature
Thermometer

Solar Intensity
Pyranograph

Humidity
Sling psychrometer

Atmospheric pressure
Barometer

Percent cloud cover
Visual estimate
Overburden drilling
Silt content
Dry sieving

Moisture content
Oven drying
Blasting
Depth of hole
Drill operator
Number of holes
Visual count

Size of blast area
Measurement

Moisture content
From mining company
Coal loading
Silt content
Dry sieving

Moisture content
Oven drying

Bucket capacity
Equipment specifications

Equipment operation
Record variations
8ulldozing
Silt content
Dry sieving

Moisture content
Oven drying

Speed
Time/distance
Dragline
Blade size
Equipment specifications
Silt content
Dry sieving

Moisture content
Oven drying

Bucket capacity
Equipment specifications

Drop distance
Visual estimate
Haul trucks
Surface silt content
Dry sieving

Vehicle speed
Radar gun

Vehicle weight
Truck scale

Surface loading
Mass/area of sample

Surface moisture content
Oven drying

Number of wheels
Visual observation
Light- and medium-
Same as for haul trucks

duty vehicles


Scraper
Same as for haul trucks

Grader
Same as for haul trucks

Wind erosion of
Surface erodibility
Dry sieving
exposed areas
Surface silt content
Dry sieving, before/after

Surface moisture content
Oven drying, before/after

Surface roughness height
Measurement
Wind erosion of
Same as for wind erosion

storage piles
of exposed areas

The meteorological parameters monitored during all tests are needed to
estimate emission rates; they are not meant to be potential correction
parameters in the emission factor equations.
T

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TABLE 3. EMISSION RATES BY SOURCE

No. of
values

Geometric mean
emission rate
Range of emission rates
from individual tests

Units
TSP
IP
TSP
IP
Drilling, ovb.a
30
lb/hole
1.16
-
0.04-7.29

Blasting, coal
14
lb/blast
28.7
10.5
1.6-514.0
0.4-142.8
Blasting, ovb.
4
lb/blast
74.3
40.0
35.2-270.0
16.9-93.9
Coal loading
(shovel/truck or
front-end loader)
25
lb/ton
0.039
0.010
007-1.090
0.002-0.378
Bulldozing, ovb.
15
lb/h
3.70
1.96
0.9-20.7
0.48-32.60
Bulldozing, coal
12
lb/h
46.0
20.5
3.0-439.0
0.9-236.0
Dragline
19
lb/yd3
0.050
0.013
0.004-0.400
0.002-0.061
Haul trucks
33
lb/VMT
9.1
4.1
0.6-73.1
0.4-42.1
Light- and
medium-duty trucks
11
Ib/VMT
2.43
1.54
0.35-9.0
0.34-5.:
Scrapers
14
lb/VMT
24.3
11.7
3.9-355.0
1.4-217.0
Graders
7
lb/VMT
5.8
2.8
1.8-34.0
0.9-15.4
Exposed area, ovb.
10
Ib/acre-s
0.0803
0.0549
0.0107-0.537
0.0073-0.336
Exposed area, coal
27
lb/acre-s
0.0980
0.0642
0.0096-2.27
0.0053-1.40
8 ovb. « overburden
8

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many of the surfaces tested. The decay In emission rates with time was explained
by the Halted quantity of particles in any specified particle size range
present on the surface (per unit area) that could be removed by wind erosion
at a particular wlndspeed. The available quantity, or erosion potential
could be restored by a disturbance of the surface such as the addition or
removal of material from a storage pile or the plowing of an exposed ground
area.
Particle Size Distrubtlon
Emission factors were developed for three size ranges—fine particulate
FP, <2.5 um); inhalable particulate (IP, <15 ^im); and total suspended particu-
late (TSP, no well-defined upper cut point, but approximated as 30 /am).
Dichotomous samplers generated the FF and IP data and hl-vol samplers generated
the TSP data. Suspended particulate (SP) emission rates determined from
exposure profiling tests were not actually TSP; rather, these rates were the
fraction of total particulates less the 30 jam in aerodynamic diameter. Only
a calculated estimate of the suspended fraction could be made because the
profiler samplers indiscriminately collect all particle sizes present in the
plume.
Independent data analyses were performed on IP and TSP/SP data to derive
emission factors for these two size ranges. Data analysis problems associated
with the very low concentrations prevented determination of emission factors
for the FP size fraction by calculation of emission rates followed by multiple
linear regression. Instead, net FP concentrations for all tests were expressed
as a fraction of TPS or SP, and the average fraction for each source was
applied to the TSP/SP emission factor for that source to calculate an FP
emission factor.
Table 8 shows the average ratios of FP and IP to TSP or SP emission rates
by source. The IP fractions were reasonably consistent, varying from 0.30 to
0.67. In general, these ratios were lower than the frequently quoted average
ratio of 0.65 for urban ambient monitoring. These ratios were based on measure-
ments taken near the sources. As the emissions proceed downwind, greater
deposition in the TSP fraction should increase the ratio.
The variation of FP/TSP ratios was much wider, from 0.026 to 0.196. The
0.196 value for bulldozing overburden appeared to be an anomaly, however.
Exclusion of this value make the range 0.026 to 0.074. The fairly consistent
ratios of FP and IP to TSP for different sources indicate that the size distri-
bution is similar in all fugitive dust sources at mines.
Three different particle sizing methods were evaluated early in the
study—cascade impactors, dichotomous samplers, and microscopy. Side-by-side
comparison of these methods showed that the cascade Impactors and dichotomous
samplers gave approximately the same particle size distributions. In contrasts,
the microscopy data varied widely. It was concluded that microscopy is a
useful tool for semiquantitative estimates of various particle types, but it
is lnadeuqate for primary particle sizing of fugitive dust emissions. Despite
several unresolved problems Involved In the generation of fine particle data
for fugitive dust sources, data from the present study are thought to be
reasonable based on their consistency and the observed agreement between
dichotomous and cascade impactor data.
9

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Deposition
The emission factors in this study were all developed from sampling data
obtained very near the source. Emissions are subject to deposition as distance
from the source increases.
A secondary objective of this study was to develop a deposition function
specifically for use with the mining emission factors* Deposition rates were
measured by two different methods—dustfall catch and apparent source depletion
at successive distances from the source. Although initial side-by-side testing
of the two methods Indicated that apparent source depletion gave the better
results, dustfall measurements were still taken at 5, 20, and 50 m from the
source as part of the exposure profiling tests; these dustfall measurements
proved to give much more reliable estimates of deposition rates during most of
the sampling at the three mines.
The deposition rates by test were correlated with several potential
variables such as wlndspeed and particle distribution. These analyses did not
reveal any significant relationships that could form the basis for an empirical
deposition function. Because these analysis were nonproductive and the primary
method for measuring deposition (apparent source depletion in upwind-downwind
sampling) gave unusable results, a deposition function cannot be presented at
this time.
If additional testing is performed to develop a deposition function,
dustfall measurement is recommended as the sampling method. The main short-
coming of dustfall as a measurement of deposition is that it measures total
particulate rather than the amount of deposition in the TSP or IF range.
Control Measures
Two mining control measures—application of water and application of a
calcium chloride solution—were evaluated by comparing emission rates from
treated and untreated areas. Testing was done on the same or adjacent lengths
of roadway under similar traffic and meteorological conditions so that the only
substantial variable between test pairs was application of the dust control. The
number of tests available for determination of control efficiencies was limited
and statistically inadequate.
The results of a 1-hour test periods immediately after watering (shovn in
Table 10) indicate that water at a rate of 0.05 gal/yd^ reduced particulate
emissions from haul roads by 60 to 70 percent and those from coal loading by
78 percent. Maintenance of that range of efficiencies would require the
reapplication of water at an approximate frequency of once per hour. Results
showed that calcium chloride still reduced particulate emission rates from an
access road by 95 percent about three months after its application, but no
information was obtained on the life expectency of this control. Application
rate for the 30 percent solution of calcium chloride was 0.6 gal/yd^.
Table 10 shows that control efficiences for IP were essentially the same
as those for TSP, whereas those for FP were slightly lower. The 60 to 70
percent control efficiency for watering haul roads was higher than the 50
10

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TABLE 8. AVERAGE PARTICLE SIZE DISTRIBUTIONS BY SOURCE
Source
No. of tests
Average
IP/TSP
Std. dev.
of IP/TSP
Average
FP/TSP
Std. dev.
of FP/TSP
Blasting
18
0.46
0.29
0.051
0.039
Coal loading
24
0.30
0.15
0.030
0.035
Bulldozing, coal
12
0.49
0.24
0.031
0.033
Bulldozing, ovb.
14
0.54
0.50
0.196
0.218
Dragline
19
0.32
0.22
0.032
0.040
Haul trucks3
28
0.52
0.08
0.033
0.037
Light- and
medium-duty
vehicles
11
0.65
0.16
0.074
0.078
Scrapers3
14
0.49
0.07
0.026
0.021
Graders3
7
0.48
0.10
0.055
0.041
Coal storage piles3
27
0.61
0.08


Exposed areas3
10
0.67
0.06


3 Expressed as fractions of SP (<30 pm) rather than TSP.
11

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percent widely reported in Che technical literature, possible because testing
was done right after the water was applied.
Comparison of Sampling Techniques
The two major sampling techniques, exposure profiling and upwind-downwind
sampling, were run simultaneously on a common source for several tests to
determine relative performance.
Profiling towers and the upwind-downwind samplers (hi-vols and dlchotomous
samplers) were placed 5, 20, and 50 m downwind of the sources to measure the
decreased In particualte flux with distance. This design allowed the indirect
determination of deposition rates. Duplicate hl-vols and dlchotomous samplers
were placed at each of three distances, and two additional hi-vols were
located 100 m downwind of the source. Upwind samplers consisted of three
hi-vols and a dlchotomous sampler, all located 20 m from the upwind edge
of the source.
Haul trucks and scrapers were selected for sampling in the comparison
study. Because they are ground-level moving point sources (line sources) that
emit from relatively fixed boundaries, both sampling methods were applicable
and the required extensive sampling array could be located without fear of the
sources changing location. Also, haul trucks and scrapers are two of the
largest fugitive dust sources at most surface coal mines.
Five tests of each source were run over a 15-day period. All five tests
of each source were performed at the same site, so only two sites (one for
each source) and one mine were involved in the comparison study.
These data were subjected to Analysis of Variance (AN0VA) to evaluate whether
differences in emission rates by sampling method, source, and downwind distance
were statistically significant. Sampling method and downwind distance were
found to have significant effects (6 - 0.20) on both TSP and IP emission
rates; emission source (haul truck or scraper) was not a significant variable.
The emission rates produced by profiling averaged 24 percent higher for TSP
and 52 percent higher for IP than corresponding upwind-downwind emisison
rates, according to the ANOVA results.
Both methods of sampling showed large overall reductions in TSP and IP
emission rates with distance. In 6 of 10 tests, however, profiling showed
lower emission rates at the closest sampling sites (5 m) than at the middle
sites (20 m). These inverted values were attributed to a systematic bias
between measurements taken by the two contractors (MRI and PEDCo), each of
whom operated one of these profilers. The reduction of IP emission rates with
distance was surprising, because very little deposition of sub-15 pm particles
was expected over a 50 m Interval.
The reason for the relatively poor comparisons between emission rates
obtained by the two sampling/calculation methods was traced primarily to the
precision of the samplers. It was not possible to establish from the data
which sampling method was more accurate because the paired results were compared
with each other rather than a known standard. Error analyses performed, after
the side-by-side sampling led to the conclusion that the accuracy of state-of-
12

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TABLE 10. CONTROL EFFICIENCIES FOR WATERING AND CALCIUM CHLORIDE
Source
Control
measure
Size
fraction
No.
tests
Avg. emission
rate, lb/VMTa
Mean
control
eff., %
Uncon-
trolled
Con-
trolled
Uncon-
trolled
Con-
trolled
Haul road,
Watering
TSPb
4
4
5.3
2.2
59
Mine 2

IP
4
4
2.8
1.1
61


FP
4
4
0.19
0.08
58
Haul road,
Watering
TSPb
4
5
16.3
5.0
69
Mine 3

IP
4
5
8.9
2.4
73


FP
3
5
0.21
0.10
54
Coal Idg.,
Watering
TSP
5
9
0.188
0.042
78
Mine 3

IP
4
9
0.053
0.010
81


FP
4
9
0.0028
0.0009
68
Access
Calcium
TSPb
3
2
6.8
0.35
95
road,
chloride
IP
3
2
5.4
0.34
95
Mine 1

FP
3
2
0.74
0.09
88
A
Emission factors for coal loading are expressed in units of lb/ton.
1 Measured as SP, the size fraction less than 30 p®-
13

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the-art testing of fugitive emissions is +25 to 50 percent with either of
these two sampling methods.
CONCLUSIONS
Resulting Emission Factors
The emission factors resulting from this study are shown in Table 12 and
are in the form of equations with correction factors for independent variables
that were found to have a significant effect (generally at the 0.05 risk
level) on each source's emission rates. The range of independent variable
values over which sampling was conducted, and for which the equations are
valid, are also shown in the table. Any ambient air quality analysis using
these emission factors should have some provision for considering deposition.
The 80 and 95 percent confidence Intervals for TSF were presented in
the report. The average 80 percent confidence interval was -20 to +24 percent,
less than the relative error anticipated in the study design.
The emission factors in Table 12 are for uncontrolled emission rates.
Control efficiencies of a few control measures were estimated in limited
testing, of the report. These control efficiences should be applied
to the calculated emission factors in cases where such controls have been
applied or are anticipated.
A comparison of the emission factors developed in this study with others
based on actual testing in surface coal mines indicated ratios of new to
existing factors ranging from 0.4 to 2.2.
Limitations to Applications of Factors
Although these emission factors were designed to be widely applicable
through the use of correction factors, the following limitations should be
considered in their application:
1.	The factors should be used only for estimating emissions from Western
surface coal mines. There is no basis for assuming they would be appro-
priate for other types of surface mining operations, or for coal mines
located in other geographic areas, without further evaluation.
2.	Correction factors used in the equations should be limited to values
within the ranges tested (see Table 15-1 of the report). This is
particularly Important for correction factors with a large exponent,
because of the large change in the resulting emission factor associated
with a change in the correction factor.
3.	These factors should be combined with a deposition function for use in
ambient air quality analyses. After evaluation of the deposition data
form this study, no empirical deposition function could be developed.
Any function subsequently developed from these data should have provision
for further deposition beyond the distance of sampling in this study.
(100-200m).
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TABLE 12. SUMMARY OF WESTERN SURFACE COAL
MINING EMISSION FACTORS
Source
TSP/P
Prediction aquation
for emission factor
FP fraction
of TSP
Units
Rang* of correction
parameters
OH 1111*
TSP
1.3
Nona
lb/hola
Non*
Blasting
TSP
IP
961 A0*8
01-4 M1"9
2SS0 A0-6
0l.S ^-3
0.090
lb/blast
A * arei blasted. ft1
« 1076 to 103,334
n ¦ Misture, X
•	7.2 to 38
0 ¦ depth of tolas, ft
•	20 to 135
Coal loading
TSP
IP
1.16/H1*2
0.119/W0"9
0.019
lb/ton
M ¦ 6.6 to 38
Bulldozing,
coal
TSP
IP
70.4 «l*2/W1*3
18.fi ."/A*"4
0.022
Ib/h
a » (11t contant, X
« 6.0 to 11.3
M > 4.0 to 22.0
Bulldozing,
ovfc.
TSP
IP
5.7 a1*2/*1*3
1.0
0.10S
lb/h
» a 3.8 to 15.1
n « 2.2 to 16.8
Oragllne
TSP
IP
0.0021 d11/*03
0.0021 d°-W-3
0.017
lb/yd3
d * drop distinct, ft
» 5 to 100
N ¦ 0.2 to 16.3
Scraper*
TSP
IP
(2.7 > lO"5)*1" V'4
(6.2 x 10"6)sJV*5
0.026
lb/YHT
c > 7.2 to 25.2
W • vehicle veight, tons
* 36 to 64
Graders
TSP
IP
0.040 S2'5
0.051 S20
0.031
Ib/WT
S « vehicle speed, aph
¦ 5.0 to 11.8
Light* and
•ediue-duty
vehicles
TSP
IP
S.79/M40
322/W4,3
0.040
lb/VHT
n « 0.9 to 1.7
Maul trucis
TSP
IP«
0.0067 »3A0-2
0.0051 »3,5
0.017
lb/VH7
w ¦ average matter of wheels
• 6.1 to 10.0
I ¦ silt loading g/ft*
¦ 3.8 to 254.0
* Silt loading Mt not a significant correction parameter for the IP fraction.
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4. The factors were obtained by sampling at the point of emission and do not
address possible reductions in emissions from dust being contained within
the mine pit.
5* As with all emission factors, these mining factors do not assure the
calculation of an accurate emission value from an individual operation.
The emission estimates are more reliable when applied to a large number
of operations, as in the preparation of an emission inventory for an
entire mine. The emission factors are also more reliable when estimating
emission over the long term because of short-term source variation.
6.. Appropriate adjustments should be made in estimating annual emissions
with these factors to account for days with rain, snow cover, temperature
below freezing, and Intermittent control measures.
7.	The selection of mines and their small number may have biased final
emission factors, but the analysis did not indicate that a bias exists.
8.	The confidence Intervals cited in Table 6, of the report, estimate
how well the equations predict the measured emission rates at the
geometric mean of each correction factor. For predicting rates
under extreme values of the stated range of applicability of the
correction factors, confidence intervals would be wider.
9.	Error analyses for exposure profiling and upwind-downwind sampling indi-
cated potential errors of 30 to 35 percent and 30 to 50 percent, respec-
tively, Independent of the statistical errors due to source variation
and limited sample size.
10.	Geometric means were used to describe average emission rates because the
data sets were distributed lognormally rather than normally. This proce-
dure makes comparison with previous emission factors difficult, because
previous factors were all arithmetic mean values.
11.	Vind erosion emission estimates should be restricted to calculation of
emissions relative to other mining sources; they should not be included
In estimates of ambient air impact.
RECOMMENDATIONS
A comprehensive study that has evaluated alternative sampling and analytical
techniques is bound to identify areas where additional research would be
valuable. Also, some inconsistencies surface during the data analysis phase,
when it is too late to repeat any of the field studies. Therefore, a brief
list of recommendations for futher study is presented here.
1.	Sampling at Midwestern and Eastern coal mines is definitely needed so
that emission factors applicable to all surface coal mines are available.
2.	A resolution of which deposition function is most accurate in describing
fallout of mining emissions is still needed. Closely related to this is
the need for a good measurement method for deposition for several hundred
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meters downwind of the source (dustfall if recommended for measurements
up to 100 or 200 m). In the present study, both the source depletion and
dustfall measurement methods were found to have deficiencies.
3.	A method for obtaining a valid size distribution of particles over the
range of approximately 1 to 50 um under near-isokinetic conditions is
needed for exposure profiling* The method should utilize a single sample
for sizing rather than building a size distribution from fractions collected
in different samplers.
4.	The emission factors presented herein should be validated by sampling at
one or more additional Western mines and comparing calculated values with
the measured ones.
5.	Standardized procedures for handling dichotomous filters should be devel-
oped. These should address such areas as numbering of the filters rather
than their petri dishes, proper exposure for filters used as blanks,
transporting exposed filters to the laboratory, equilibrating filters
prior to weighing, and evaluation of filter media other than Teflon for
studies where only gravimetric data are required*
6.	One operation determined in the study design to be a significant dust-
producing source, shovel/truck loading of overburden, was not sampled
because it was not performed at any of the mines tested. Sampling of
this operation at a mine in Wyoming and development of an emission factor
would complete the list of emission factors for significant sources at
Western coal mines (see Table 2-1 of the report).
7.	Further study of emission rate decay over time from eroding surfaces is
needed. In particular, more information should be obtained on the effect
of wind gusts in removing the potentially erodible material from the
surface dur.'ng period when the average windspeed is not high eniugh to
erode the surface.
8.	More testing of controlled sources should be done so that confidence in
the control efficiencies is comparable to that for the uncontrolled
emission rates.
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