U.S. DEPARTMENT Of COMMERCE
Natkxul T«ch«ial lifomutlon Suite
PB-281 043
Emissions from' fhe Crushed
Granite Industry
State-of-trie-Art
Monsanto Research Corp, Dayton, Ohio
Prepared for
Industrial Environmental Research Lab -Cincinnati, Ohio
Feb 78
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TECHNICAL REPORT DATA
fflette rttd Intlnictlont on the nvint bit fart completing)
v REPORT NO.
EPA-600/2-7B-021
3.'RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
EMISSIONS FROM THE CRUSHED GRANITE INDUSTRY
State of the Art
5. REPORT DATE
February 1978 issuing date
8. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
P. K. Chalekode, J. A. Peters, T. R. Blackwood,
and S. R. Archer
8. PERFORMING ORGANIZATION REPORT NO.
MRC-DA-706
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Monsanto Research Corporation
1515 Nicholas Road
Dayton, Ohio 45407
ID. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
68-02-1874
12. SPONSORINO AGENCV NAME AND ADDRESS
Industrial Environmental Research Laboratory-Cin., OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE'Or REPORT AND PERIOD COVEiREO
Task Final, 4/75 - 7/77
14. SPONSORING AGENCY CODE
EPA/ 600/12
IS. SUPPLEMENTARY NOTES
IERL-Ci project leader.for this report is Roger C. Wilihoth, 513-684-4417
tB. ABSTRACT
This report describes a study of atmospheric emissions from the crushed
granite industry. The potential environmental effect of this emission
source was evaluared using source severity, defined as the ratio of the
maximum time-averaged ground leve.1* concentration of a pollutant at a
representative plant boundary to a hazard factor. The hazard factor is
the ambient air quality standard for criteria pollutants and an adjusted
threshold limit value for noncriteria pollutants. Pollutants are emitted
from several operations including drilling, blasting, transport on unpaved
roads, crushing, screening, conveying, and stockpiling. Emission factors
are determined for particulates emitted from trace operations. The emis-
sion rate of respirable particulates (<7 (ym) is 6.9 kg/hr. The major
hazardous constituent in the dust is free silica (27.2% by weight).,
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air pollution
Carbon monoxide
Dust
Silicon dioxide
Granite
Nitrogen oxides
b.lOENTIFIERS/OPEN ENDED TERMS c, COSATI Field/Group
Air.pollution control
Stationary sources
Source severity
Particulate
50 B
IB. DISTRIBUTION STATEMENT
Unlimited
IB. SECURITY CLASS ITnll Rrpart)
Unclassified
20 SECURITY CLASS (Thllp»ft)
Unclassified
21. NO. OF
_) Tb
31 PRICE
EPA Foim »10>l IB-TJI
* u.t Mwnwenmimieomct int— 720-335/5033
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EPA-600/2-78-021
February 1978
EMISSIONS FROM THE
CRUSHED GRANITE INDUSTRY
State of the Art
by
P. K. Chalekode, J. A. Peters, T. R. Blackwood, and S. R. Archer
Monsanto Research Corporation
Dayton, Ohio 45407
Contract No. 68-02-1874
Project Officer
Roger C. Milmoth
Resource Extraction and Handling Division
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental
Research Laboratory-Cincinnati, U.S. Environmental Protection
Agency, and approved for publication. Approval does not signify
that the contents necessarily reflect the views and policies of
the U. S. Environmental^ Pro^t
trade names or commercial products constitute endorsement or
recommendation for use.
ii
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FOREWORD
When energy and material resources are extracted, processed,
converted, and used, the related pollutional impacts on our
environment and even on our health often require that new and
increasinglyjnprei efficient pollution control methods be used.
The industrial Environmental Research Laboratory - Cincinnati
(lERL-Ci) assists in developing and demonstrating new and im- •
proved methodologies that will meet these needs both efficiently
and economically.
This report contains an assessment of air emissions from the
crushed granite industry. This study was conducted to provide a
better understanding of the distribution and characteristics of
emissions from crushed granite operations. Further information
on this subject may be obtained from the Extraction Technology
Branch, Resource Extraction and Handling Division.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
iii
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PREFACE
The Industrial Environmental Research Laboratory (IERL) of the
U.S. Environmental Protection Agency (EPA) has the responsibility
for insuring that pollution control technology is available for
stationary sources to meet the requirements of the Clean Air Act,
the Federal Water Pollution Control Act, and solid waste legisla-
tion. If control technology is unavailable, inadequate, uneco-
nomical, or socially unacceptable, then financial support is
provided for the development of the needed control techniques for
industrial and extractive process industries. Approaches con-
sidered include: process modifications, feedstock modifications,
add-on control devices, and complete process substitution. The
scale of the control technology programs ranges from bench- to
full-scale demonstration plants.
IERL has the responsibility for developing control technology for
a large number (>500) of operations in the chemical and related
industries. As in any technical program, the first step is to
identify the unsolved problems. Each of the industries is to be
examined in detail to determine if there is sufficient potential
environmental risk to justify the development of control tech-
nology by IERL.
Monsanto Research Corporation (MRC) has contracted with EPA to
investigate the environmental impact of various industries that
represent sources of pollutants in accordance with EPA's respon-
sibility, as outlined above. Dr. Robert C. Pinning serves as MRC
Program Manager in this overall program, entitled "Source Assess-
ment," which includes the investigation of sources in each of
four categories: combustion, organic materials, inorganic mater-
ials, and open sources. Dr. Dale A. Denny of the Industrial Pro-
cesses Division at Research Triangle Park serves as EPA Project
Officer for this series. Reports prepared in this program are
of two types: Source Assessment Documents, and State-of-the-Art
Reports.
Source Assessment Documents contain data on pollutants from spe-
cific industries. Such data are gathered from the literature,
government agencies,, and cooperating companies. Sampling and
analysis are also performed by the contractor when the available
information does not adequately characterize the source pollu-
tants. These documents contain all of the information necessary
for IERL to decide whether a need exists to develop additional
control technology for specific industries.
iv
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State-of-the-Art Reports include data on pollutants from specific
industries which are also gathered from the literature, govern-
ment agencies, and cooperating companies. No extensive sampling,
however, is conducted by the contractor for such industries.
Sources in this category are considered by EPA to be of insuffi-
cient priority to warrant complete assessment for control tech-
nology decisionmaking. Therefore, results from such studies are
published as State-of-the-Art Reports for potential utility by
the government, industry, and others having specific needs and
interests.
This State-of-the-Art Report contains data on air emissions from
the crushed granite industry. This project was initiated by the
Chemical Processes Branch of the Industrial Processes Division at
Research Triangle Park; Mr. D. K. Oestreich served as EPA Project
Leader. The project was transferred to and completed by the
Resource Extraction and Handling Division, lERL-Cincinnati, where
Mr. Roger C. Wilmoth served as EPA Task Officer.
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ABSTRACT
This report describes a study of air pollutants emitted by the
crushed granite industry. The potential environmental effect of
the source was evaluated using source severity values (source ••
severity is the ratio of the maximum time-averaged ground level
concentration of an emission to its hazard factor).
In 1972, 155 crushed granite processing plants in the U.S.
operated 412 quarries and produced 96.5 million metric tons of
crushed granite.
A typical crushed granite plant has a production rate of 450 met-
ric tons/hr and emits pollutants from several operations includ-
ing drilling, blasting, transport on unpaved roads, crushing,
screening, conveying, and stockpiling. The emission factor- for
total particulates emitted from the representative plant is
49 kg/hr; blasting contributes 74% of the overall emissions. The
emission rate of respirable particulates is 6.9 kg/hr. The major
hazardous constituent in the dust is free silica (27.2% by
weight), prolonged exposure to which may result in the develop-
ment of a pulmonary fibrosis known as silicosis. Nitrogen oxides
and carbon monoxide are emitted by the blasting operation, but
the emission factors and corresponding source severities are
small in comparison to particulate emissions.
The affected population value for an emission is defined as the
number of persons living in areas beyond the plant boundary where
the source severity is 0.1 or greater. The maximum source sever-
ity for total particulates is calculated as 0.99. The population
affected value for total particulate emissions from the crushed
granite industry is 610 persons. Similarly, the source severity
due to free silica in the respirable particulate emissions is
32.7, and the affected population is 31,400 persons. The indus-
try is expected to grow at a rate of 4% per year, and by 1978 its
emissions are predicted to increase by 28% over the 1972 level.
This report was submitted in partial fulfillment of Contract No.
68-02-1874 by Monsanto Research Corporation under the sponsorship
of the U.S. Environmental Protection Agency. The study covers
the period April 1975 to July 1977, and the work was completed in
August 1977.
vi
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CONTENTS
Foreword . . .ill
Preface . . iy
Abstract vi
Figures , . viii
Tables viii
Abbreviations and Symbols . . . , ix
Conversion Factors and Metric Prefixes . , . xi
1. Introduction . . . 1
2. Summary ..... ........... 2
3. Source Description .... 5
Process description . , . . , » . , 5
Factors affecting emissions 6
Geographical distribution 7
4. Emissions 9
Selected pollutants .......... 9
Characteristics 9
Definition of a representative source . 10
Environmental effects 12
5. Control Technology 16
State of the art 16
Future considerations ...... 16
6. Growth and Nature of the Industry ........... 20
Present technology 20
Emerging technology . 20
Production trends 20
References . . 22
Appendices
A. Literature survey .......... 25
B. Sampling - details and results ... . • .31
C. Source severity and affected population . . 47
Glossary ..... 51
vii
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FIGURES
Number
1 State and nationwide emission burden due to total
particulate emissions from crushed granite
operations 4
2 Crushed granite operation . . . 5
3 Emission rate of total particulate from crushed
granite operations 8
TABLES
1 Mass Emissions from Various Operations in the
Crushed Granite Industry 3
2 Crushed Granite Sold or Used by Producers in the
United States in 1972, by State . 8
3 State and Nationwide Particulate Emissions Burden
from Crushed Granite Industry 11
4 Pollutant Source Severity Equations 14
5 Source Severity and Affected Population for
Emissions from the Crushed Granite Industry . . 14
viii
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ABBREVIATIONS AND SYMBOLS
A — cross-sectional area of the falling granules, cm*
B — width of conveyor belt, cm
D — representative distance from the major source, m
DT — total dose, g-s/m3
d — height of material fall, cm
E — emission factor, g/kg
ED — function of five variables that influence dust
emissions from drilling operations
F — hazard factor, g/m3
G — gravitational acceleration = 980 cm/s2
h — physical stack height
H ,— effective emission height, m
AH — plume rise
mi / m2 -•- slopes used in calculating distances to samplers
M — belt load, g/cm2
P — production rate of crushed limestone, metric tons/hr
Q — emission rate, kg/hr or g/s (Equation 1)
Q_ — line source emissions per length of line, g/m
Q_ — total release, g
R — specific formation of airborne respirable dust, g
S — maximum source severity, dimensionless
Sof'.Si* — high-volume sampler locations
TLV — threshold limit value, g/m3
u — 4.5 m/s (approximate U.S. average wind speed)
U- — linear speed of the conveyor belt, cm/s
a
x<• YH — Cartesian coordinates used to relate position of
the i-th sampler to the source
x — downwind distance from source along the dispersion
centerline
x — crosswind distance from the line source, m
c
ix
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ABBREVIATIONS AND SYMBOLS (continued)
y, y. •— lateral distance from dispersion centerline to
sampler, m
z — vertical distance from the x-y plane of the source
to the sampler plane
a — angle defined for use in calculating sampler
positions, radians
.6 — wind azimuth angle with respect to the y axis,
radians
ir — a constant
PP — material density of coal, g/cm3
a — overall standard deviation, m
a — horizontal standard deviation of plume dispersion, m
a — vertical standard deviation of plume dispersion, m
z
a — instantaneous vertical dispersion parameter, m
X -- ground level concentration, g/m3
X- — ground level concentration at coordinate location
(x., y., 0), g/m3
X — maximum ground level concentration, g/m3
ITlu.rC.
:ime-
dose, g/s-m3
X — maximum time-averaged ground level concentration,
max g/m3
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CONVERSION FACTORS AND METRIC PREFIXES
Conversion factors
To convert from
centimeter (cm)
centimeter2 (cm2)
centimeter3 (cm3)
kilogram (kg)
kilogram (kg)
kilometer2 (km2)
meter (m)
meter2 (m2 )
meter3 (m3)
meter3 (m3)
meter3 (m3 )
metric ton
radian (rad)
Prefix Symbol
kilo k
centi c
milli m
micro p
to
foot
inch2
inch3
pound-mass (Ib mass
avoirdupois)
ton (short, 2,000 Ib
mass)
mile2
foot
foot2
foot3
gallon (U.S. liquid)
liter
pound-mass
degree ( ° )
Metric prefixes
Multiplication
factor
10 3 1 kg =
10~2 1 cm =
10~3 1 mm =
10""6 1 ym =
Multiply by
3.281 x 10~2
1.550 x 10-1
6.102 x 10~2
2.204
1.102 x 10-3
3.860 x ID"1
3.281
1.076 x 101
3.531 x 10 1
2.642 x 102
1.000 x 10~3
2.205 x 103
5.730 x 101
Example
1 x 10 3 grams
1 x 10~2 meter
1 x 10~3 meter
1 x 10~6 meter
aMetric Practice Guide. ASTM Designation E 380-74, American
Society for Testing and Materials. Philadelphia, Pennsylvania,
November 1974. 34 pp.
xi
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SECTION 1
INTRODUCTION
The conversion of naturally occurring granite to its crushed form
involves mining from open quarries and processing at finishing
plants. Air pollution problems are attendant to the mining and
the processing operations.
An investigation of crushed granite operations was conducted to
provide a better understanding of the distribution and character-
istics of emissions than had been previously available in the
literature. Data collection was designed to document the need
for developing control technology in this industry.
This report contains information on the following items:
• A method to estimate the emissions due to crushed
granite processing
• Composition of emissions
• Hazard potential of emissions
• Geographical distribution and source severity
• Trends in the crushed granite industry and their effects
on emissions
• Type of control technology used and proposed
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SECTION 2
SUMMARY
The crushed granite industry converts naturally occurring granite
rock deposits into crushed granite for use predominantly (94% of
the output) in the construction industry. In 1972, 155 process-
ing plants in the U.S. operating 412 quarries (an average of 2.7
quarries per plant) produced 96.5 million metric tons3 of crushed
granite. Contingency forecasts of crushed granite demands in the
year 2000 have been reported to be 332 to 419 million metric
tons.
Atmospheric emissions of particulates occur from several unit
operations: drilling, blasting, transport on unpaved roads,
crushing, screening, conveying, and stockpiling. The emission
factor for respirable particulates from crushed granite process-
ing is 1.53 x 10~2 kg/metric ton, with blasting contributing
about 88% of the value. The hazardous constituent in the dust is
free silica (27.7 wt % average), which may cause the development
of silicosis.
A typical crushed granite plant has a production rate of
450 metric tons/hr and emits dust at the rate of 6.9 kg/hr respi-
rable particulate and 49 kg/hr total particulate.
To assess the source severity, the ratio of the maximum ground
level concentration at the representative plant boundary to the
pollutant hazard factor is used. The hazard factor is defined as
the EPA primary air quality standard. When EPA criteria do not
exist, an adjusted threshold limit value (TLV®) which allows for
exposure time and for the general population is used. The maxi-
mum source severity due to free silica emissions (respirable
fraction) from a representative plant is 32.7.
Table 1 summarizes the severity and contributions of emissions
from the various unit operations. Figure 1 summarizes the contri-
butions of particulate emissions from the crushed granite indus-
try on a state and national basis.
al metric ton = 106. grams; conversion factors and metric system
prefixes are presented in the prefatory pages.
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TABLE 1. MASS EMISSIONS FROM VARIOUS OPERATIONS IN THE CRUSHED GRANITE INDUSTRY
Unit operation
Drilling
Blasting
Loading onto
haul trucks
Dumping to
primary crusher
Primary crusher
Secondary crushing
and screening
Conveying
Unloading to
stockpiles
Loading from
stockpiles
Vehicular movement
on dry unpaved roads
Windblown emissions
TOTAL0
Emission
factor,
kg/metric ton
3.99 x 10-"
7.96 x Mr2
b
2.1 x UT"
2.2 x 10-z
b"
b-
4.91 x 10-3
1.07 x i(rl
U.S. total
k«j/yr
38,500
7,681,400
5
20,300
2,123.000
b'
473,800
10,325,500
Particulates*
Percent
of Severity for
total representative plant
0.4 3.7 x 10"3
74.4 0.74
b b
0.2 1.9 x ID"3
b b
20.6 0.20
bh
— — w
b b
b b
u u
4.6 4.5 x 10~2
bh
u
100.0 0.99
Percent
respirable
10.0
16.9
b
3.6
h
3.6
b
17.6
b-
—
14.3
Free silica
U.S. total Severity for
kq/yr representative plant
1,040 8.5 x 10-2
353,000 28.7
b b
• •
200 , 1.6 x ID"2
bh
ii
20,800 1.7
bh
u
b b
bh
u
22,700 1.8
bh
u
402,000 32.7
The values shown are for total particulates.
Negligible.
CData nay not add to totals due to independent rounding.
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NONE
U.S. AVERAGE - 0.06*
Figure 1. State and nationwide emission burden
due to total particulate emissions
from crushed granite operations.
Nitrogen oxides and carbon monoxide are emitted by the blasting
operation with respective emission factors of 2.85 g/metric ton
and 1.68 g/metric ton of material blasted. The maximum source
severities due to nitrogen oxides and carbon monoxide are 8.9 x
8.9 x 10~2 and 1.7 x lO'1*, respectively. Similarly, the emission
factor of fibers from a representative plant is 3.13 x 109
fibers/metric ton and the resulting severity is 0.45.
The crushed granite industry is concentrated near granite
deposits, adjacent to large, rapidly expanding urban areas, and
in areas where large-scale public and private works are under
construction. The distribution of plants with respect to the
size of localities shows that free silica in the respirable
particulate emissions from a representative crushed granite plant
affect a population of 31,400 persons to a severity of 0.1. The
industry is predicted to grow at the rate of 4% per year, and by
1978 the emissions are estimated to increase 28% from 1972 levels.
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SECTION 3
SOURCE DESCRIPTION
PROCESS DESCRIPTION
Emission Sources
The conversion of naturally occurring granite deposits into
crushed granite involves a series of physical operations (Fig-
ure 2). The deposits are first loosened by drilling and blasting.
Granite is then loaded and transported to the processing plant by
trucks or belt conveyors. Processing includes such operations as
crushing, pulverizing, screening, and conveying. After process-
ing, the granite is loaded for shipment to customers or to stock-
piles for storage.
TRANSPORT
CRUSHING.
PULVERIZING,
SCREENING.
AND SIZING
CONVEYING STORAGE
TRANSPORT
Figure 2. Crushed granite operation.
5
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Fine particulates (<7 pm) emission sources in the crushed granite
industry can be divided into two categories: 1) sources associ-
ated with actual processing such as crushing, screening, and
transfer operations; and 2) fugitive dust sources such as vehicle
traffic on unpaved roads, transport operations, and stockpiles.
Quarrying operations such as drilling, blasting, fracturing and
loading are also fugitive dust sources.
Source Composition
Granite is a plutonic igneous rock with a chemical composition
(by weight) of about 72% silica, 13% alumina, 3% ferrous oxide
and magnesia, 1% lime, and 9% potash and soda. Its mineralogical
composition is ^43% alkali feldspar, 30% quartz, 10% plagioclase
feldspar and 13% ferromagnesia minerals (1).
FACTORS AFFECTING EMISSIONS
Calculation of the source severity and the state and national
emissions burdens, necessitates a knowledge of the emission rate
for every source in the country. Conducting emission measure-
ments on a source-by-source basis was impractical due to the
large number of individual sources and the diversity of source
types. A method was therefore developed to derive an emission
factor as kilograms of particulates emitted per metric ton of
crushed granite processed.
The emission rate for each of the source types is estimated as
the product of the emission factor and the crushed granite produc-
tion rate, expressed as metric tons per hour. This relationship
can be stated as:
Q = E x P (1)
where Q = emission rate of particulates, kg/hr
E = emission factor for particulates, kg/metric ton
of crushed granite processed
P = production rate cf crushed granite, metric ton/hr
The overall emissions from crushed granite operations are due to
drilling, blasting, loading, vehicular movement on unpaved roads,
crushing, conveying, screening, and stockpiling. Emissions from
all of these unit operations (except blasting) are influenced by
particle size distribution, rate of handling, moisture content of
the handled material, and type of equipment used.
(1) Clews, F. H. Heavy Clay Technology, Second Edition.
Academic Press, New York, New York, 1969. pp. 1, 4.
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A detailed literature survey was conducted to obtain published
data on the extent to which various factors influence the overall
emissions, and on the relative contributions of the unit opera-
tions to overall emissions (see Appendix A). Lack of quantita-
tive data necessitated on-site sampling to develop the emission
factor.
Emissions from a crushed granite plant, were sampled. (See Appen-
dix B for details and results of the sampling.) The results show
that' blasting contributes 74% of the total particulate plant
emissions. The results also show that the emissions from other
unit operations can be reduced if the moisture content is
increased.
GEOGRAPHICAL DISTRIBUTION
In the United States, 155 crushed granite processing plants (2)
operating 412 quarries (personal communication with W. Pajalich,
Bureau of Mines, Washington, D.C., 15 October 1975) had a total
output of 96.5 million metric tons in 1972 and 109.1 million
metric tons in 1973. Georgia ranked first with 26.9 million
metric tons in 1972, followed by North Carolina, Virginia, South
Carolina, California, and New Jersey. Together these six states
accounted for 82.5% of the toal crushed granite production in the
United States (3). Table 2 gives the crushed granite output and
the respective population densities for 14 states in the United
States. Emission rates for particulates due to crushed granite
operations are given in Figure 3.
Geographically, the crushed granite industry is concentrated in
large, rapidly expanding urban areas and in areas where large-
scale public and private works are under construction.
(2) 1972 Census of Mineral Industries, Subject Series; General
Summary. MIC 72(1)-1, U.S. Department of Commerce,
Washington, D.C., 1975. 174 pp.
(3) Mineral Industry Surveys. U.S. Department of the Interior,
Washington, D.C., 1972. 12 pp.
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tUOQ.-auric tontfyr
2100 BUT
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SECTION 4
EMISSIONS
SELECTED POLLUTANTS
The major pollutants emitted from crushed granite processing are
dusts containing free silica. The prolonged inhalation of these
dusts may result in the development of a disabling pulmonary fi-
brosis known as silicosis. Silica causes a progressive diffuse,
nodular lung fibrosis that may continue to increase for several
years after exposure is terminated. The first and most common
symptoms of uncomplicated silicosis are dry coughing and short-
ness of breath on exertion. As the disease advances, the short-
ness of breath becomes worse and the cough more troublesome.
Further progress of the disease results in marked fatigue, loss
of appetite, pleuritic pain, and total incapacity to work. Ex-
treme cases may eventually result in death from destruction of
the lung tissues (4).
The American Conference of Governmental Industrial Hygienists has
suggested a TLV (in mg/m3) of 10/(% quartz + 2) for respirable
dusts containing quartz or free silica. Further, particulate is
one of the criteria pollutants. Dusts with less than 1% silica
are termed "inert;" a TLV of 10 mg/m3 has been suggested for
them (5).
CHARACTERISTICS
Mass Emissions
The mean emission factor for total particulates is 0.107 kg/met-
ric ton of granite processed through the primary crusher. The
mean emission factor for respirable particulates is 0.002 kg/met-
ric ton. Blasting contributes 74% of the overall plant emissions.
The foregoing results are based on a sampling of two crushed
(4) Sax, N. I. Dangerous Properties of Industrial Materials,
Third Edition. Reinhold Book Corporation, New York,
New York, 1968. pp. 1088-1089.
(5) TLVs® Threshold Limit Values for Chemical Substances and
Physical Agents in the Workroom Environment with Intended
Changes for 1976. American Conference of Governmental
Industrial Hygienists, Cincinnati, Ohio, 1976. p. 32.
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granite plants (see Appendix B for details). The emission fac-
tors for nitrogen oxides and carbon monoxide are 2.85 g/metrie
tons and 1.68 g/metric tons, respectively (6).
The emission factor for total particulates (Q'.IO? kg/metric ton)
was used to estimate the statewide emissions from crushed granite
processing, as shown in Table 3. Of all the emitted pollutants,
particulates are the only criteria pollutant. The state emission
burden is calculated as the percent contribution of particulate
emission rates for crushed granite processing in a state to the
total particulate emission rates in that state. Table 3 displays
the total particulate emission by state (7), the 1972 particulate
emissions from granite processing by state, and -the state and
nationwide emission burdens. The emissions of particulates due
to crushed granite processing contribute less than 1% to the
overall particulate emissions in each state in the U.S.
Composition of Emissions
An analysis of the emissions from crushed granite (Appendix B)
shows that free silica, constituting 27.7% by weight, is the only
known hazardous component. Other emission constituents (72.3% by
weight) are considered inert.
DEFINITION OF A REPRESENTATIVE SOURCE
Consultations with industry experts show that crushed granite
plants have an average production rate of 450 metric tons/hr
(personal communication with F. Renniger, National Crushed Stone
Association, Washington, D.C., 7 November 1975). The mean emis-
sion factor was determined by sampling two crushed granite plants
believed to be representative of the industry (Appendix B). The
representative plant thus emits dust at a rate of 6.9 kg/hr res-
pirable particulates and 43.6 kg/hr total particulates.
The representative population density, the average population
density of the six leading crushed granite-producing states of
Georgia, North Carolina, Virginia, South Carolina, California,
and New Jersey, is equal to 100 persons/km2. The representative
distance from the plant is defined using the major contributing
source within the plant as a reference point. The distance of
the plant boundaries from this reference point is taken as the
radius of a circle whose area is equal to the area of the
(6) Blackwood, T. R., P. K. Chalekode, and R. A. Wachter. Source
Assessment: Crushed Stone. Contract 68-02-1874, U.S. Envi-
ronmental Protection Agency, Cincinnati, Ohio, July 1977.
91 pp.
(7) 1972 National Emissions Report. EPA-450/2-74-012, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, June 1974. 422 pp.
10
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TABLE 3. STATE AM) HATICNNIDE PARTICUIATE EMISSIONS BURDEN
FROM CRUSHED GRMJUE EfflXJSTRZ
State
Alaska
California
Georgia
Maine
New Hampshire
New Jersey
North Carolina
Pennsylvania
Rhode Island
South Carolina
Virginia
Washington
Wisconsin
Wyoming
Other states
U.S. TOTAL3
Total
particulate
emissions,
metric tons/yr (7)
14,000
1,006,000
404,000
49,000
15,000
152,000
481,000
1,810,000
13,000
199,000
477,000
162,000
412,000
75,000
11,491,000
15,762,000
Particulate
emissions
from granite
processing (1972) ,
metric tons/yr
3
518
2,882
10
5
246
2,536
34
32
925
1,385
121
123
149
1,334
10,322
Contributions of
crushed granite
emissions to
overall state
emissions, %
0.02
0.05
0.71
0.02
0.03
0.16
0.53
Negl .
0.24
0.47
0.29
0.07
0.03
0.18
0.01
0.06
Data may not add to totals shown due to independent rounding.
-------
representative plant. Assuming crushed granite plants have the
same average area as crushed stone plants (0.53 km2), the
representative distance to the plant bpundaries is 410 m (6).
A representative plant growing at the same rate as the industry
will grow at a predicted rate of 4% per year, and by 1978 its
emissions will increase by an estimated 28% over 1972 levels.
ENVIRONMENTAL EFFECTS
The source severity indicates the hazard potential of a represen-
tative emission source; it is the ratio of the maximum ground
level concentration (x) to a hazard factor (F). A mathematical
model describing the dispersion of pollutants in the atmosphere
is employed to calculate the source severity, S (which equals
X/F). For open sources, the model uses the concentration of a
pollutant occurring at a single point at ground level at the
plant boundary. This concentration can occur at one point in
time during a year and can thus be considered a worst-case con-
dition. The hazard factor is derived from ambient air quality
criteria or reduced threshold limiting values.
Ground Level Concentration
The minimum distance at which public exposure to the pollutant
could occur is the distance from the major contributing emission
source to the representative crushed granite plant boundary—
410 m as shown earlier in this section. The following formula, in
conjunction with class C meteorological conditions, was used to
calculate the concentration at this distance which is defined
as Xm9 (8) (the maximum ground level instantaneous concentration):
max
xmax ~ irffv°zu
where Q = mass emission rate, g/s
a - 0.209 x°-903
a - 0.113 x°-911
7,
u = 4.5 m/s (approximate U.S. average)
The instantaneous ground level concentration for total particu-
lates at 410 m is thus 736 yg/m3. This is corrected to the time
(8) Turner, D. B. Workbook of Atmospheric Dispersion Estimates.
Public Health Service Publication No. 999-AP-26,
U.S. Department of Health, Education, and Welfare,
Cincinnati, Ohio, May 1970.
12
-------
averaged maximum, Xmax* for 24 hours (9) so that the mean concen-
tration becomes 258 ug/m3. This means that over a 24-hr period,
the average maximum ground level concentration at the boundary of
the representative plant is 258 yg/m3 above the background levels.
Hazard Factor
Since no ambient air quality standard exists for free silica, the
hazard factor, F, is defined as follows:
P = 2? x x TLV
The derivation of F utilizes the TLV corrected from 8-hr to 24-hr
exposure with a safety factor of 100 applied to the calculation.
For the purpose of this report, the free silica hazard factor is
calculated as 11.3 pg/m3. It should be compared to the respir-
able emissions, since the TLV used in its definition is for
respirable emissions. For total particulates,. F shall be defined
as the 24-hr ambient air quality standard of 260 pg/m3.
Source Severity
For the representative crushed granite plant, the maximum sever-
ity is determined from the ratio of the time-averaged maximum
ground level concentration of the emission species to the hazard
factor for the species (Xmax/F^- Tne time-averaged maximum
ground level concentration is related to the mass emission rate,
Q (in g/s) , of a pollutant, and for open sources, the represen-
tative distance, D, from the source to the plant boundary.
The approach described above leads to the equations in Table 4 ,
which were used to determine the severity of criteria and non-
criteria pollutants from the crushed granite industry (10).
These equations simplify the calculations of source severity and,
ultimately, of the affected population.
(9) Nonhebel, G. Recommendations on Heights for New Industrial
Chimneys. Journal of the Institute of Fuel, 33:479, 1960.
(10) Blackwood, T. R., and R. A. Wachter. Source Assessment:
Coal Storage Piles. Contract 68-02-1874, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
July 1977. 96 pp.
13
-------
TABLE 4. POLLUTANT SOURCE SEVERITY EQUATIONS
Pollutant
Particulate
Nitrogen oxides
Carbon monoxide
Noncriteria pollutant
, Source
severity equation
S —
S —
S =
S —
4,020 Q
Dl.81
22,200 Q
D1 «90
44.8 Q
D1-81
316 Q
TLV»DI . si
where S = source severity
Q = mass emission rate
D = distance from source to plant boundary
TLV = threshold limit value
Table 5 shows the source severities due to, and the population
affected by, emissions of criteria and noncriteria pollutants
from the crushed granite industry. Severity can also be calcu-
lated by taking the ratio Xmax/F* Thus, for total particulates
(xmav = 258 yg/m3 and P = 260 yg/m3) , the severity is 0.99.
Sample calculations for source severity and affected population
are provided in Appendix C.
TABLE 5. SOURCE SEVERITY AND AFFECTED POPULATION FOR
EMISSIONS FROM THE CRUSHED GRANITE INDUSTRY
population , a
Pollutant _ Source severity _ persons
Total particulates
Free silica
Nitrogen oxides
Carbon monoxide
Fibers
0.99
32.7
0.089
1.7 x 10-1*
0.454
610
31,400
0
0
227
Population living beyond the plant boundary where the
source severity is 0.1 or greater.
14
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-------
SECTION 5
CONTROL TECHNOLOGY
STATE OP THE ART
Currently there is no designated air pollution control technology
or methodology to control emissions from crushed granite opera-
tions. Dust generated from the various operations is dependent
upon the dryness of the handled material; hence, any method used
to add moisture is helpful in controlling dust levels. Natural
phenomena such as rain or snow and in-process washing or spraying
operations inhibit dust emissions as the dust adhering to water
is less prone to be emitted. Some plants apply water to unpaved
roads in order to curb emissions due to vehicular movement on the
roads, and some employ wet drilling to reduce emissions while
drilling blast holes.
FUTURE CONSIDERATIONS
The fugitive and point sources of dust in the processing of
granite are drilling, blasting, loading, unpaved road transport,
crushing, screening, conveying, and stockpiling.
Dust emissions from dry percussion drilling operations can be
controlled by adding water or water mixed with a surfactant into
the air used for flushing the drill cuttings from the hole.
Dilution ratios range from 800 to 3,000 parts of water to 1 part
surfactant. An 89-iran diameter hole requires about 26 £/hr of
solution. This permits the drill cutting to be blown from the
hole as damp, dust-free pellets (11).
In conventional mining of coal, water-filled plastic bags with or
without solid stemming material (clay) are used for stemming dust
emissions from blast holes. This method reduces dust concentra-
tions by 20% to 80% and explosive consumption by about 10% (12) .
Instead of liquids, "thixotropic" cellulose or bentonite pastes
can be used; gelatinous in repose, they liquefy when disturbed.
Similar control methods may be applicable to the reduction of
particulate emissions from blasting in granite mining.
(11) Jones, H. R. Fine Dust and Particulates Removal. Noyes
Data Corporation, Park Ridge, New Jersey, 1972. 307 pp.
(12) Grossmueck, G. Dust Control in Open Pit Mining and Quarry-
ing. Air Engineering, 10(25):21, 1968.
16
-------
Release of carbon monoxide, nitrogen oxides, and other gases such
as aldehydes and hydrogen can be curtailed by having a dry blast
hole and by carrying out the detonation properly to prevent
incomplete combustion.
Loading of the blasted granite into trucks by front end loaders
results in dust emissions. Wetting of the broken stone with
water or water mixed with a surfactant will alleviate the dust
emissions. Emissions due to wind erosion during transport can be
reduced by covering the load with a tarpaulin of by wetting its
surface with water or water mixed with chemicals.
Water application is also an effective method for controlling
emissions from unpaved roads; however, approximately 5% to 8%
moisture (by weight) must be applied to suppress the dust emis-
sions (13). Additives such as calcium chloride can be used to
reduce the surface tension of water so that the dust can be
wetted with less water. Calcium chloride can be applied at a
cost of approximately $0.15/m2 treated/yr (14). The major prob-
lem involved in its use is its corrosion of vehicle bodies and
leaching by rain water or melting snow.
Another effective method of dust control is to mix stabilizing
chemicals into the road surface to a depth of approximately 20 mm
to 50 mm (15). One cement company uses a special emulsion agent3
and a treatment which involves spraying a solution of 4 parts of
water and 1 part of the emulsion agent at the rate of 9.1 £/m3 of
the road surface. Certain pretreatment measures such as working
the road surface into a stiff mud are necessary to prevent the
binder in this emulsion agent from sticking to the vehicles.
Periodic maintenance using a 1:7 emulsion agent/water solution
spray keeps the emulsion agent binder active. This dust control
program was found to give 3 yr of service at a total cost of
$0.12/m2.
aCoheren, supplied by Golden Bears Division, Wetco Chemicals
Company.
(13) Dust Suppression. Rock Products, 75:137, May 1972.
(14) Vandegrift, A. E., L. J. Shannon, P. G. Gorman, E. W. Law-
less, E. E. Sallee, and M. Reichel. Particulate Pollutant
Systems Study, Volume III: Handbook of Emission Properties.
Contract CPA-22-69-104, U.S. Environmental Protection Agency,
Durham, North Carolina, May 1971. 607 pp.
(15) Significant Operating Benefits Reported from Cement Quarry
Dust Control Programs. Pit and Quarry, 63(7):116, 1971.
17
-------
In some counties in Iowa, mixing cutback asphalt into the road
surface to a depth of 50 mm to 80 mm has been investigated (16).
This type of surface treatment reduces dust emissions, but it
requires periodic maintenance such as patching of the potholes.
Treating the road surface with oil once a month is another
efficient method of controlling unpaved road dust emissions. The
cost for such applications is estimated to be $0.10/m2 treated/yr
(11). However, a New Jersey study shows that 70% to 75% of the
oil applied moves from the surface of the road to the surrounding
ecosystem by dust transport and runoff. The oil or its heavy
metal constituents such as lead may cause ecological harm (17).
Furthermore, surface oiling requires regular maintenance because
roads treated in this manner develop potholes.
Lignin sulfonates, byproducts from paper manufacture, are also
used to control dust emissions. A commercially available lignin
sulfonate* was tested on a farm access road at Arizona State
University (18). The method proved quite successful, giving 5 yr
of service and effective dust suppression at a cost of $0.47/m2
for 5 yr ($0.10/m2-yr).
Paving the road surface is the best method for controlling
dusts, but it is impractical due to the high cost and the tempo-
rary nature of crushed granite plants.
The simplest and least expensive means of controlling dust from
crushing, screening, conveying, and stockpiling is through the
use of wetting agents and sprays at critical points.w A crushed
rock production plant uses a dust suppression system and a
chemical wetting agent. Approximately 4 £ of the concentrated
wetting agent is diluted 1,000 times by volume with water using
an automatic proportioner. The solution is sprayed at the top
and bottom of cone crushers at the rate of 4.2 SL of solution per
metric ton of material being crushed. This system also helps
reduce dust emissions at transfer points, screening operations,
aOrzan A, supplied by Crown Zellerbach Corporation.
Chem-Jet, supplied by Johnson-March Corporation.
(16) Hoover, J. M. Surface Improvement and Dust Palliation of
Unpaved Secondary Roads and Streets. ERI Project 856-S,
Iowa State Highway Commission, Des Moines, Iowa, July 1973.
97 pp.
(17) Freestone, F. J. Runoff of Oils from Rural Roads Treated to
Suppress Dust. EPA R2-72-054, U.S. Environmental Protection
Agency, Cincinnati, Ohio, October 1972. 29 pp.
(18) Bub, R. E. Air Pollution Alleviation by Suppression of Road
Dust. M.S.EL. Thesis, Arizona State University, Tempe,
Arizona, June 1968. 45 pp.
18
-------
storage bins and stockpiling operations (19). Such a system has
many cost-saving advantages. It requires no ducts, hooding or
.other enclosures for crushers, screens, or conveyors. The equip-
ment is in the open and allows the operators to see the material
flow. The dust is not collected, and there is no solid waste
disposal or water pollution problem.
In a crushed stone plant (with processes similar to those of a
crushed granite plant), a baghouse is used to control dust emis-
sions from cone crushers, scalping and twin sizing screens, and
shuttle and transfer conveyors.
The range of dust collected is 2,722 kg to 5,443 kg in a 10-hr
day from a 182 metric ton/hr plant (20). A baghouse does not
provide for dust control in stockpile areas unless these areas
are totally enclosed. The dust collected in the baghouse pres-
ents a solid waste problem. The alternative disposal methods are
to put the dust into settling basins or to develop sales opportu-
nities. Depending on the type of material and the local market
conditions, uses may include manufactured sand, underslab fill,
and asphalt filler (21).
(19) Harger, H. L. Methods Used by Transit Mix Operators to Meet
Air Pollution Control District Requirements. National Sand
and Gravel Association and National Ready Mixed Concrete
Association, Washington, D.C., April 1971. 22 pp.
(20) Trauffer, W. E. Maine's New Dust-Free Crushed Stone Plant.
Pit and Quarry, 63(2):96, 1970.
(21) Ozol, M. A., S. R. Lockete, J. Gray, R. E. Jackson, and
A. Preis. Study to Determine the Feasibility of an
Experiment to Transfer Technology to the Crushed Stone
Industry. Contract NSF-C826, National Science Foundation,
June 1974. 50 pp.
19
-------
SECTION 6
GROWTH AND NATURE OF THE INDUSTRY
PRESENT TECHNOLOGY
Present technological improvements include the use of larger and
more efficient crushing and screening plants. Primary crushing
is often done near the pit with jaw or gyratory crushers. Second-
ary crushing is done by cone crushers or gyratories. The crushed
granite is screened and sent to open area storage. In larger and
more efficient plants, granite is drawn out through tunnels under
storage piles, and mixing equipment is used to blend any desired
mixture of sizes.
EMERGING TECHNOLOGY
This study did not reveal emerging technology of specific impor-
tance to air pollution control in the crushed granite industry.
PRODUCTION TRENDS
Production of crushed granite is tied very closely to the granite-
consuming industries. The production of crushed granite is
associated chiefly with the needs of the construction industry
(3)/ which was more than 94% of the crushed granite output.
Production of crushed granite was 96.5 million metric tons in
1972. In 1973, a total of 109.4 million metric tons, and in
1974, 107.5 million metric tons of crushed granite were either
shipped or used by producers in the United States (22). Assuming
the same annual growth rate as that for the sand and gravel
industry (3.9% to 4.7%), the contingency forecast of crushed
granite demand in the year 2000 is 330 to 420 million metric
tons.
Transportation constitutes a major part of the delivered cost of
crushed granite. These costs may exceed the sales value of the
material at the processing plants, even though crushed granite
plants are located near the point of use. Local zoning and envi-
ronmental regulations and depletion of urban deposits may necessi-
tate the location of future crushed granite plants much farther
(22) Mineral Industry Surveys. Annual Advance Summary. U.S.
Department of the Interior, Washington, D.C., September 17,
1975. 12 pp.
20
-------
-------
REFERENCES
1. Clews, F. H. Heavy Clay Technology, Second Edition.
Academic Press, New York, New York, 1969. pp. 1, 4.
2. 1972 Census of Mineral Industries, Subject Series: General
Summary. MIC 72(1)-1, U.S. Department of Commerce,
Washington, D.C., 1975. 174 pp.
3. Mineral Industry Surveys. U.S. Department of the Interior,
Washington, D.C., 1972. 12 pp.
4. Sax, N. I. Dangerous Properties of Industrial Materials,
Third Edition. Reinhold Book corporation, New York,
New York, 1968. pp. 1088-1089.
5. TLVs® Threshold Limit Values for Chemical Substances and
Physical Agents in the Workroom Environment with Intended
Changes for 1976. American Conference of Governmental
Industrial Hygienists, Cincinnati, Ohio, 1976. p. 32.
6. Blackwood, T. R., P. K. Chalekode, and R. A. Wachter.
Source Assessment: Crushed Stone. Contract 68-02-1874,
U.S. Environmental Protection Agency, Cincinnati, Ohio,
July 1977. 91 pp.
7. 1972 National Emissions Report. EPA-450/2-74-012, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, June 1974. 422 pp.
8. Turner, D. B. Workbook of Atmospheric Dispersion Estimates.
Public Health Service Publication No. 999-AP-26, U.S. Depart-
ment of Health, Education, and Welfare, Cincinnati, Ohio,
May 1970. 84 pp.
9. Nonhebel, G. Recommendations on Heights for New Industrial
Chimneys. Journal of the Institute of Fuel, 33:479, 1960.
10. Blackwood, T. R., and R. A. Wachter. Source Assessment:
Coal Storage Piles. Contract 68-02-1874, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
July 1977. 96 pp.
22
-------
11. Jones, H. R. Fine Oust and Particulates Removal. Noyes
Data Corporation, Park Ridge, New Jersey, 1972. 307 pp.
12. Grossmueck, G. Dust Control in Open Pit Mining and Quarry-
ing. Air Engineering, 1Q(25):21, 1968.
13. Dust Suppression. Rock Products, 75:137, May 1972.
14. Vandegrift, A. E., L. J. Shannon, P. G. Gorman,
E. W. Lawless, E. E. Sallee, and M. Reichel. Particulate
Pollutant Systems Study, Volume III: Handbook of Emission
Properties. Contract CPA-22-69-104, U.S. Environmental Pro-
tection Agency, Durham, North Carolina, May 1971. 607 pp.
15. Significant Operating Benefits Reported from Cement Quarry
Dust Control Programs. Pit and Quarry, 63(7):116, 1971.
16. Hoover, J. M. Surface Improvement and Dust Palliation of
Unpaved Secondary Roads and Streets. ERI Project 856-S,
Iowa State Highway Commission, Des Moines, Iowa, July 1973.
97 pp.
17. Freestone, F. J. Runoff of Oils from Rural Roads Treated to
Suppress Dust. EPA R2-72-054, U.S. Environmental Protection
Agency, Cincinnati, Ohio, October 1972. 29 pp.
18. Bub, R. E. Air Pollution Alleviation by Suppression of Road
Dust. M.S.E. Thesis, Arizona State University, Tempe,
Arizona,. June 1968. 45 pp.
19. Harger, H. L. Methods Used by Transit Mix Operators to Meet
Air Pollution Control District Requirements. National Sand
and Gravel Association and National Ready Mixed Concrete
Association, Washington, D.C., April 1971. 22 pp.
20. Trauffer, W. E. Maine's New Dust-Free Crushed Stone Plant.
Pit and Quarry, 63(2):96, 1970.
21. Ozol, M. A., S. R. Lockete, J. Gray, R. E. Jackson, and
A. Preis. Study to Determine the Feasibility of an Experi-
ment to Transfer Technology to the Crushed Stone Industry.
Contract NSF-C826, National Science Foundation, June 1974.
50 pp.
22. Mineral Industry Surveys. Annual Advance Summary. U.S.
Department of the Interior, Washington, D.C., September 17,
1975. 12 pp.
23. Chaiken, R. F., E. B. Cook, and T. C. Rune. Toxic Fumes
from Explosives. Ammonium Nitrate-Fuel Oil Mixtures.
Bureau of Mines RI-7867 (PB 233 496), U.S. Department of the
Interior, Washington, D.C., May 1974. 29 pp.
23
-------
24. Chalekode, P. K., and T. R. Blackwood, Source Assessment:
Transport of Sand and Gravel. Contract 68-02^-1874,
U.S. Environmental Protection Agency, Cincinnati, Ohio.
(Preliminary document submitted to the EPA by Monsanto
Research Corporation, December 1974.) 87 pp.
25. Cheng, L. Formation of Airborne-Respirable Dust at Belt
Conveyor Transfer Points. American Industrial Hygiene
Association Journal, 34 (12):540-546, 1973.
26. Cowherd, C. Development of Emission Factor for Fugitive
Duat Sources. EPA-450/3-74-037, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
June 1974. 172 pp.
27. Blackwood, T. R., T. F. Boyle, T. L. Peltier, E. C. Eimutis,
and D. L. Zanders. Fugitive Dust from Mining Operations.
Contract 68-02-1320, Task 6, U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina, May 1975.
p. 34.
28. Andresen, W. V. Industrial Hygiene Design in Raw Materials
Handling Systems. American Industrial Hygiene Association
Journal, 23(6):509-513, 1962.
29. Lilienfeld, P., and J. Dulchinos. Portable Instantaneous
Mass Monitor for Coal Mine Dust. American Industrial
Hygiene Association Journal, 33(3):136, 1972.
30. Eimutis, E. C., and M. G. Konicek. Derivations of Continuous
Functions of the Lateral and Vertical Atmospheric Dispersion
Coefficients. Atmospheric Environment, 6(11):859-863, 1972.
31. Martin, D. 6., and J. A. Tikvart. A General Atmospheric
Diffusion Model for Estimating the Effects on Air Quality of
One or More Sources. Presented at the 61st Annual Meeting
of the Air Pollution Control Association, St. Paul,
Minnesota, June 23-27, 1968. 18 pp.
24
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APPENDIX A
LITERATURE SURVEY
A study was made to predict and analyze those parameters affect-
ing dust emissions from the seven handling operations in crushed
limestone processing:
• Drilling and blasting
• Transport
• Conveying
• Unloading
• Open storage
• Loading
• Crushing/grinding/sizing
There were two major classifications of parameters: those
dependent on the material, and those dependent on the operation.
Material-dependent parameters are generally the same for all
operations. These are: moisture content, density, and "dustiness
index," which will be defined as the mass of respirable dust ad-
hering to 2.2 kg of material. Density, delineates differences in
particle size distribution between different samples of the same
material. The "dustiness index" is used to determine differences
in emissions from different materials undergoing the same opera-
tion. Parameters dependent on the operation are as varied as the
operations themselves.
DRILLING AND BLASTING OPERATIONS
The following factors influence the dust emissions from drilling
operations:
• Number of bits
• Sharpness of the bits
• Speed of the bits
• Depth of bit penetration
• Experience of the machine operator
25
-------
The literature search did not yield quantitative data indicating
.a relationship between the emission factor (ED) and the afore-
mentioned factors. A qualitative relationship might possibly
resemble:
E
E
.
D 2 4) 5)
where the numbers in parentheses represent functions of the
respective variables shown above.
Of all the unit operations, blasting as a cause of dust emissions
has been studied least. The literature search yielded a poten-
tial list of factors influencing emissions; frequency of blasting,
bulk moisture content of the rock, particle size distribution,
type and amount of explosive, and hole size.
Studies have been conducted on the magniture of gaseous emissions
of nitrogen oxides and carbon monoxide from blasting. Stoichio-
• metric ratios of ammonium nitrate-fuel oil (ANFO) mixtures (5.5%
fuel oil) should not produce nitrogen oxide and carbon monoxide
emissions. Theoretically, a higher percentage of fuel oil should
not give nitrogen oxides; it should yield more carbon monoxide
and carbon dioxide. Conversely, a lower percentage of fuel oil
should not produce carbon monoxide, and it should give more
nitrogen oxides than nitrogen.
Experimental investigations by the Bureau of Mines (23) show that
4% fuel oil results in 1.3 m3 (at standard conditions) of NOX per
kg of ANFO and 1.3 m3 of CO per kg of APNO, while 6% fuel oil
results in 0.32 m3 of NOX per kg of ANFO and 1.8 m3 of CO per kg
of ANFO. The maximum emission factor figures have been used for
the severity calculations.
TRANSPORT OPERATIONS
Transport operations are discussed in detail in another assess-
ment document (24) .
(23) Chaiken, R. F., E. B. Cook, and T. C. Ruhe. Toxic Fumes
from Explosives. Ammonium Nitrate-Fuel Oil Mixtures.
Bureau of Mines RI-7867 (PB 233 496), U.S. Department of
the Interior, Washington, D.C., May 1974. 29 pp.
(24) Chalekode, P. K., and T. R. Blackwood. Source Assessment
Transport of Sand and Gravel. Contract 68-02-1874, U.S.
Environmental Protection Agency, Cincinnati, Ohio. (Pre-
liminary document submitted to the EPA by Monsanto Research
Corporation, December 1974.) 87 pp.
26
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CONVEYING OPERATIONS
Dust emissions from conveying operations come from windblown dust
during open conveying and conveyor discharge.
Emissions from conveyor discharge and parameters affecting these
emissions have been evaluated (25) . The material was freshly
mined coal, cut during a dry operation and placed in plastic bags
to maintain its natural surface moisture of about 0.8% as meas-
ured by a SoiltesiT Speedy Moisture Tester. The following rela-
tionship was found:
R- 8.50 x 10 - (A-2)
where R = specific formation of airborne respirable dust, g
_A = cross-sectional area of the falling granules, cm2
PC = material density of the coal, g/cnr
G = gravitational acceleration = 980 cm/s2
d = height of fall, cm
M = belt load, g/cm2
B = width of the conveyor belt, cm
UB - linear speed of the conveyor belt, cm/s
The study lea'd to the following conclusions:
• About 10% of the adhering respirable dust becomes
airborne by the impact of dropping.
• Reduction of the height of material fall reduces the
formation of airborne respirable dust.
• For heavy belt loads (coal bed thickness » mean lump
size), an increase in the thickness of the coal bed
reduces the specific formation of airborne respirable
dust.
UNLOADING OPERATIONS
Emissions from unloading operations are produced by dropping
materials from conveying machinery onto storage piles. A recent
study (26) showed that the emission factors, E, for unloading
(25) Cheng, L. Formation of Airborne-Respirable Dust at Belt
Conveyor Transfer Points. American Industrial Hygiene
Association Journal, 34(12):540-546, 1973.
(26) Cowherd, C. Development of Emission Factor for Fugitive
Dust Sources. EPA-450/3-74-037, U-.S. Environmental Protec-
tion Agency, Research Triangle Park, North Carolina, June
1974. 172 pp.
27
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operations, based on milligrams of suspended dust particles
<3{3 lam in diameter per kilogram of aggregate unloaded, obeyed
fallowing relationship:
P = 20 mg of particulate .- ,.
kg of aggregate IA-JJ
This emission factor was based on high volume sampling at a sand
and gravel plant in the Cincinnati area. E was dependent on the
surface moisture of the material, estimated by the Precipitation-
Evaporation (P-E) Index.
For an analysis of other factors affecting emissions from unload-
ing operations, see Section 3, "Conveying Operations." Although
the relationships derived for emissions from conveyor discharge
are based on coal conveyance, only a correction factor for the
relative dustiness of the material handled need be applied to
make the equation applicable to all conveying and unloading
operations.
• . *
OPEN STORAGE
Emissions due to open storage have.been discussed to detail in
previous documents (9,25,27).
LOADING OPERATIONS
Emissions from loading operations occur in the transfer of mate-
rial from storage to transporting vehicles. For aggregates, this
transfer is accomplished by power shovels or front-end loaders
scooping the material from open storage piles and dumping it
into transporting vehicles, usually trucks. Dust rises from the
scooping and the dropping processes.
Emissions from dropping are determined by many of the same para-
meters that determine dust formation from conveyor discharge,
although there are definite dissimilarities in mode of discharge
between conveyor belts and power shovels. Dust emissions should
be determined by:
1) Height of material fall
2) Quantity of material dumped
3) Density of material
4) Rate at which material is dumped
(27) Blackwood, T. R., T. F. Boyle, T. L. Peltier, E. C. Eimutis,
and D. L. Zanders. Fugitive Dust from Mining Operations.
Contract 68-02-1320, Task b, U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina, May 1975.
p. 34.
28
-------
5) Moisture content of material
6) "Dustiness index" of material
An equation determining the amount of respirable dust, R, formed
by power shovel discharge, based on an equation for conveyor dis-
charge, should be of the form:
R a (D(3)(6) (A_4)
K a (2) (4) (5)
-------
The factors affecting discharge emissions are the same as those
for conveyor and power shovel discharge (see "Conveying Opera-
tions" and "Loading Operations" above).
Dust emissions from size reduction are judged to be influenced by:
• "Dustiness index" of material
• Moisture content of material
• Degree of particle-size reduction
• Rate of material flow through
size reducer
A qualitative expression for respirable dust formation, R, is
believed to be:
R a
(2)T
where each number in parenthesis is some function of the respec-
tive parameter listed above.
An induced air flow must be present for atmospheric dispersion
of the respirable dust. For most crushers, which operate at a
relatively low speed, air flow is induced only during discharge.
(See "Conveying Operations" above for a quantitative evaluation
of air flow induced by discharge.)
High speed pulverizers create air flow during size reduction as
well as discharge. Air flow induced by high speed size reduc-
tion may be inferred from the literature to be inversely propor-
tional to the rate of material flow through the size reducer (28).
(28) Andresen, W. V.- Industrial Hygiene design in Raw Materials
Handling Systems. American Industrial Hygiene Association
Journal, 23 (6)..-509-513, 1962.
30
-------
APPENDIX B
SAMPLING - DETAILS AND RESULTS
SAMPLING SITE DESCRIPTION
The purpose of the sampling is to obtain data on plant emissions
from various unit operations for which no published data were
available.
Two crushed granite plants were chosen whose operations are repre-
sentative of the crushed granite industry. Further, these plants
were located in areas with favorable meteorological conditions
for sampling.
Plant A
At this site/ the blasted rock is loaded into the primary
crusher by a front-end loader or shell loader. The granite rock,
processed through the primary crusher 2.13-m cone and secondary
crusher 1.68-m cone, is fed by a conveyor to a screen tower
where it falls into a bin. From the bin, the material is loaded
into railroad cars or trucks. The material may then be delivered
directly to customers, or it may be stockpiled. The crushed
granite from the stockpile is loaded into trucks by a conveyor.
The plant operates on a continuous basis at 10 hr/day for 5
days/week. The average production rate of material processed
through the primary crusher is 680 metric tons/hr; that through
the secondary screening house is 430 metric tons/hr.
The major dust emission control method is the application of
water to the haul roads from the quarry area to the plant. The
quarry operations and the primary crushing take place in a pit
and hence are only minor contributors to the overall plant emis-
sions. The major contributor is the secondary crushing and
screening unit. The sampling data and the results are given in
Table B-l.
Plant B
At this site, the blasted material is loaded out with two 4.2-m3
shovels into six 32-metrie ton trucks to be hauled and dumped
into a 107-cm x 122-cm jaw crusher. The material is then proc-
essed through two scalping screens and then through two 1.7-m
31
-------
TABLE B-l. SAMPLING DATA AND RESULTS
u»
ro
a
Coordinates, m
Unit operation
Secondary crushing-screening
Secondary crushing-screening
Secondary crushing-screening
Secondary crushing-screening
Drilling, dry
Dump to first crusher
Dump to first crusher
Secondary crushing-screening
Secondary crushing-screening
Secondary crushing-screening
Secondary crushing-screening
Blasting
Overall plant emission
Overall plant emission
Overall plant emission
Overall plant emission
Secondary crushing
Secondary crushing
Secondary crushing
Secondary crushing
Secondary crushing
Secondary crushing
Secondary crushing
Secondary crushing
Secondary crushing
Drilling, wet
Drilling
Drilling
Drilling
Drilling
Drilling
"see Figure B-l. T = total
X
300
310
390
320
78
60
60
288
258
375
274
2,300
540
570
660
520
60
60
60
120
120
160
60
60
160
90
90
90
90
90
90
y
0
120
0
100
20
0
0
83
209
108
193
0
0
120
0
180
15
15
15
30
30
0
0
0
40
22
22
0
22
0
0
particulate; R
2
0
0
0
0
0
0
0
0
0
0
0
230
0
0
0
0
0
0
0
0
0
0
0
0
o
0
0
0
0
0
0
Wind Sampling Emission Total or Atmospheric
speed, time. Concentration, rate, respirable stability
mph min ug/m3 cr/s particulate'' class
5.0
5.0
5.0
5.0
3.0
3.0
3.0
6.7
6.7
6.7
6.7
7.0
4.0
4.0
4.0
4.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
= respirable
Plant A -
230 687.7
230 759.6
230 628.3
230 1.154.8
4 1.540.0
4 370.0
4 260.0
Plant A -
235 949.6
235 632.9
235 775.6
235 .1.006.6
45 763.4
Plant B -
235 424.2
235 525.6
235 323.2
235 518.3
720.0
1,190.0
1,320.0
200.0
150.0
380.0
2,330.0
2,570.0
14O.O
70.0
130.0
560.0
130.0
120.0
130.0
particulate. Two dumps
Run 1
3.562
3.235
2.273
Run 2
1.908
Run 1
9.573
3.606
5.959
6.610
3.939
2.954
5.520
5.650
6.232
4.888
1.159
2.152
6.728
2.152
1.442
1.562
' d~ "
One dump
1.870
2.641
2.281
3.890
x 10~l
x 10-3
x 10-3
2.153
2.421
2.482
3.631
x 10s
1.009
1.609
x 10~l
1.858
X 10-2
X lO-2
x ID"2
x ID'2
X ID"2
x ID'2
x ID"2
X ID'2
x 10-2
x 10-2
X ID'2
X ID'3
X ID"2
X 10~3
X 10"3
One truck
T
T
T
T
Rc
Rd
Rfl
T
T
T
T
T
T
T
T
T
T
Re
R6
R
R
R
R
R
R
f
T
T
T
R
R
passed.
C
C
C
C
C
C
D
D
D
D
D
D
D
D
D
D
B
B
B
B
B
B
B
B
B
D
D
D
D
D
D
-------
cone crushers. From here, crushed granite is conveyed by a 152-m
belt conveyor to a secondary plant.
At the secondary plant, 13 screens separate the aggregate sizes,
and the crushed granite is then fed into one of two blending
tunnels. From that blender, it is either trucked to customers
or to storage, or loaded into railroad cars. The fine crushings
are fed to two 2.1-m short-head crushers and transferred to a
sand plant. The wet slurry from the screenings is fed to a sump
that pumps it to a settling pond. About 90% of the pond water
is reused in the process.
The plant operates on a continuous basis at 10 hr/day for 5
days/week. The average production rate through the primary
crusher is 590 metric tons/hr, the same as the processing rate
through the secondary crusher.
The major dust emission control method is the use of wet screen-
ing operations. However, unlike Plant A, vehicular traffic on
the haul roads is a major contributor of overall plant emissions.
The sampling data and the results are given in Table B-l.
SAMPLING PROCEDURES
Samplers
General Metal Works® high-volume (hi-vol) samplers were posi-
tioned around an area as shown in Figure B-l. For this arrange-
ment, the origin was defined as the source, and all remaining
points were in the usual Cartesian coordinate system. The angle
of mean wind direction was 6. The downwind distance of any point
y* perpendicular to the wind direction centerline was computed in
the following manner:
mi = tan 0
and for point S. with coordinates x., y.
= ^i
2 xi
the angle a was found from
a =» arctan , —-• _
i 2
the lateral distance, Y.^, is:
Y. = (sin a) /x.2 + y.2
33
-------
METHMOlOGICAl STATION
Figure B-l. Sampling arrangement.
and the downwind distance, X^, is:-
XA = (cos o) /x.^2 + y^2
These values are used in appropriate dispersion models. The
sampling time for hi-vol samplers was about 4 hours. Five dif-
ferent hi-vol samplers were used to monitor the area emissions
at positions S0, Slr 82, 83, and Si*.
A GCAa respirable dust monitor was used to obtain downwind con-
centrations of respirable and total particulates from unit opera-
tions (29). The sampling time for the 6CA instrument was about
4 minutes, so only one unit was necessary to monitor at all the
positions (not simultaneously).
a
GCA Corporation, Technology Division, Redford, Massachusetts.
(29) Lilienfeld, P., and J. Dulchinos. Portable Instantaneous
Mass Monitor for Coal Mine Dust. Americal Industrial
Hygiene Association Journal, 33(3):136, 1972.
34
-------
The hi-vol samplers collect particles <100 ym in size, while the
GCA unit collects <10-ym particles with a cyclone separator and
<50-ym particles without a cyclone separator.
Models
Diffusion models, normally used to predict concentrations sur-
rounding a point source of known strength, are used in reverse
for open source sampling. Several concentration readings are
taken to calculate the source strength of an open source.
Models applicable to the sampling arrangement and source charac-
teristics are chosen and utilized for each emissive source. Two
models are used in this study. The first represent emissions
from secondary crushing and screening, dry drilling, dump to
first crusher, overall plant emission, secondary crushing, wet
drilling, and drilling.
This is the point source model (7) where:
X (x, y, z; H) -
oxp -i fZ-=-Sr +exp -i SJJir '"-"
The notation used to depict the concentration is x (x, y, z; H).
H, the height of the plume centerline from the ground level when
it becomes essentially level, is the sum of the physical stack
height, h, and the plume rise, AH. The following assumptions are
made: the plume spread has a Guassian distribution in both the
horizontal and vertical planes, with standard deviations of plume
concentration distribution in the horizontal and vertical of oy
and oz, respectively; the mean wind speed affecting the plume
is u; the uniform emission rate of pollutants is Q; and total
reflection of the plume takes place at the earth's surface, i.e.,
there is no deposition or reaction at.the surface. Any consis-
tent set of units may be used. The most common is x in g/m3, Q
in g/s, u in m/s, and Oy, az, H, x, y, and z in meters. The
concentration x is a mean over the same time interval as the time
interval for which the o's and u are representative. The values
of both Oy and az are evaluated in terms of the downwind dis-
tance, x, and stability class. Stability classes are determined
conveniently by graphical methods as shown in Figure B-2 (26) .
Given the downwind distance, x (30), continuous functions are
(30) Eimutis, E. C. , and M. G. Konicek. Derivations of Continuous
Functions of the Lateral and Vertical Atmospheric Dispersion
Coefficients. Atmospheric Environment, 6(11):859-863, 1972.
35
-------
U)
en
START
ATMOSPHERIC
CUSS ISO
RADIATION INDEX = -2
RADIATION INDEX =
-1
Figure B-2. Flow chart of atmospheric stability class determination (26)
-------
then used to calculate values for oy, and oz, using the constants
shown in Table B-2 and Table B-3 (31). In open source sampling,
the sampler is maintained in the center of the plume at a constant
distance; the plume has no effective height (H = 0); and the con-
centrations are calculated at ground level. Equation B-l thus
reduces to (7):
X (x' °' °' 0) - ¥^Tu- (B"2)
The second model is used in computing total dose from a finite
release in blasting. This is calculated from the dose model,
Equation B-3 (7):
is the total release in grams from the source, and DT is the
total dose in g-s/m3. Other parameters in Equation B-3 are the
same units as Equation B-l. Again, the dose is the product of
the concentration and sampling time.
Data Collection
Each variable for each of these models was determined in the
field by high volume sampling at a nonportable meteorological
station. Wind speeds were averaged every minute with a mean
recorded for each 15-minute interval. The mean wind speed was
calculated from the average of the 15-minute recordings over the
entire run. The wind direction variation was less than ±45° from
the centerline during the samplings. The samplers were therefore
maintained within the plume during sampling.
The concentration at sampler S0 was subtracted from the concen-
trations at Si, 82, 83, and S4 to yield those due to the source
emissions. Mass emission rate was then calculated as an average
of the calculations done for N sampler readings using the appro-
priate dispersion equation.
The respirable dust monitor was mounted on the portable meteoro-
logical station shown in Figure B-3. Each monitor concentration
reading was displayed by direct digital readout. The wind meter,
connected to the anemometer atop a 3.05-m pole, was read every
15 s. The mean wind speed was determined by averaging the 15-s
(31) Martin, D. 0., and J. A. Tikvart. A General Atmospheric
Diffusion Model for Estimating the Effects on Air Quality of
One or More Sources. Presented at the 61st Annual Meeting
of the Air Pollution Control Association, St. Paul,
Minnesota, June 23-27, 1968. 18 pp.
37
-------
TABLE B-2.
CONTINUOUS FUNCTION FOR LATERAL ATMOSPHERIC
DIFFUSION COEFFICIENT o (30)
Ax
0.9031
Stability class
A
B
C
D
E
F
A
0.3658
0.2751
0.2089
0.1471
0.1046
0.0722
TABLE B-3. CONTINUOUS FUNCTION FOR VERTICAL ATMOSPHERIC
DIFFUSION COEFFICIENT 1,000 A
B
C
D
E
F
100 to 1,000 A
B
C
D
E
F
<100 A
B
C
D
E
F
AI
0.00024
0.055
0.113
1.26
6.73
18.05
, A2
0.0015
0.028
0.113
0.222
0.211
0.086
A3
0.192
0.156
0.116
0.079
0.063
0.053
BI
2.094
1.098
0.911
0.516
0.305
0.18
B2
1.941 '
1.149
0.911
0.725
0.678
0.74
B3
0.936
0.922
0.905
0.881
0.871
0.814
Cl
-9.6
2.0
0.0
-13
-34
-48.6
C2
9.27
3.3
0.0
-1.7
-1.-3
-0.35
C3
0
0
0
0
0
0
38
-------
ANEMOMETER
/I
CUPBOARD.
-ANEMOMETER
HOUSING
CYCLONE SEPARATOR
WEATHER POLE
RESPIRAIU DUST
MONITOR
SAMPLING PLATFORM
IPWATCH
TRIPOD STAND
Figure B-3. Sampling apparatus.
readings. Distance x was approximated by pacing over the rough
terrain. For each sampling run, all these data were recorded in
the field on the form shown in Figure B-4. The time of day and
atmospheric stability (determined according to the flow chart in
Figure B-2) were recorded periodically on the bottom of the form.
The terms used on the field data form are explained in Table B-4.
Any factors that might have affected concentration or emission
rate were mentioned in the column labeled "Comments." When this
form was completed, the data were programmed into a computer and
the emission rate, Q, calculated in accordance with the model
specified in the column labeled "M."
EMISSION LEVELS
The parameters in Equation B-l were measured in the field to ob-
tain the emission rate (Q) per unit operation. These data were
recorded on the form shown in Figure B-4 and printed out via com-
puter. These values are shown in Table B-l, where the value of
Q from the appropriate dispersion model was automatically com-
puted. Using the site data presented earlier in this appendix,
emission factors were computed as follows for each operation.
39
-------
MODEL: POINT-1
LINE = 2
SOURCE TYPE
DATE.
BY_
*>.
o
IAJ3L J
UNIT OPERATION
WIND
SPED
MPH
DIS1
X
FANC
Y
E, FT
TIME,
MIN.
READ.
mg/tn3
CONC.
R/T
BCD
Ap ^
Q,
g
s1
M
COMMENTS
TOTAL SAMPLING TIME MULTIPLY READING BY
TIME OF DAY 4 MINUTES 1
ATM.STABILITY * . 8 MINUTES 0.46
16 MINUTES 0.23
20 MINUTES 0.184
30 MINUTES 0.122
37 MINUTES 0.1
Figure B-4. Field data form.
-------
TABLE B-4. EXPLANATION OP FIELD DATA FORM TERMS
Term
Meaning
Read, mg/m3
Cone., vg/m3
R/T
BGD, yg/m3
A, yg/m3
Q, g or g/s
S1
M
Concentration reading
Converted concentration for sampling
times greater than 4 min (lower
right-hand corner)
Ratio of respirable to total
particulate
Background concentration
The difference between the converted
concentration and the background
Calculated emission rate
Stability for the time of day the
unit operation was sampled
The model used referenced as 1, 2,
or 3 (point, line, or dose,
respectively)
Blasting
From the sampling data (Plant A, run 2), the emission rate of
total particulates due to blasting is 1.9 x 106 g/blast.
Assuming that one blast supplies the primary crusher with 3.5
days work (data from plant personnel) and knowing that Plant A
has a production rate of 750 tons/hr operating for a lO-'hr day,
the amount of rock released by each blast is:
750 i0^- x 10
hr
x 3.5 days = 26,250 tons
The emission factor for total particulate due to blasting is thus:
Ep _ (1.9 x 106 g) (IP"3 kg/g)
(26,250 tons) (0.9078 metric ton/ton)
= 7.96 x 10~2 kg total particulate/metric ton
Sampling of crushed stone operations indicates that
the ratio of respirable particulates to total particulate (R/T)
is 0.169. Assuming the same ratio for crushed granite blasting,
the emission factor is-:
EF = (7.96 x 10~2) (0.169) = 1.35 x 10~2 kg respirable particulate/
metric ton
41
-------
Drilling
It is assumed that the representative plant uses wet drilling and
that the total drilling time per blast is 176 hours. The emis-
sion rate for drilling is the average of the four wet drilling
emission rates (Plant B, run 1) cmd is equal to 0.015 g total
particulate/s. The emission factor is therefore:
Ep _ (0.015 g/s) (176 hr/blast) (3,600 s/hr)(1Q"3 kg/g)
(26,250 tons/blast)(0.9078 metric tons/ton)
= 3.99 x lO'4 kg total particulate/metric ton
Since the average of the two respirable emission rates is
1.5 x 10"3 g/s, the ratio of respirable particulates to total
particulates (R/T) is thus 10%. The respirable particulate emis-
sion factor is:
EF = (3.99 x ID"1* kg/metric ton) (0.10)
= 3.99 x 10~5 kg respriable particulate/metric ton
Secondary Crushing and Screening
The average emission rate from secondary crushing and screening
(Plang A, runs 1 and 2) is 2.67 g togal particulate/s. Using the
production rate for Plant A, the emission factor is:
EF = (2.67 g/s) (3,600 s/hr) (hr/475 tons)
(10~3 kg/g) (ton/0.9078 metric ton)
= 2.2 x 10~2 kg total particulate/metric ton
From the sampling data (Plant B, run 1), the R/T ratio can be
calculated for secondary crushing. The average emission rate for
secondary crushing is 4.84 x 10~2 g respirable particulate/s.
The emission rate for total particulates as sampled by hi-vol
samplers (determined from averaging the emission rates for over-
all plant emission) is 1.356 g total particulate/s. The R/T
ratio for secondary crushing is thus:
4.84 x 10-2
1.356 U*UJb
The respirable particulate emission factor from secondary crush-
ing and screening is assumed to be 3.6% of the total particulate
emission factor and is equal to 8.58 x lO"1* kg respirable partic-
ulate/metric ton.
42
-------
Secondary Crushing Only—
From the sampling data (Plant B, run 1), the average emission
rate of respirable particulates due to secondary crushing (ex-
cluding the run during which one truck passed the sampling area)
is 4.84 x 10~2 g respirable particulate/s. Assuming R/T equals
0.039, the emission rate of total particulates is 1.24 g total
particulate/s. Using the production rate for Plant B, the emis-
sion factor is:
EF = (1.24 g/s) (3,600 s/hr)(hr/650 tons)
(ton/0.9078 metric ton)(10~3 kg/g)
= 7.6 x 10"3 kg total particulate/metric ton
The plant used wet screening and, hence, there were no signifi-
cant emissions from the screening operation.
Secondary Screening Only—
Since dry screening was used in Plant A, the emission factor is
determined by subtracting the secondary crushing emission factor
from the secondary crushing and screening emission factor;
EF = 2.2 x 10"2 kg/metric tons - 7.6 x 10"3 kg/metric tons
* 1.44 x 10~2 kg total particulate/metric ton
Dumping to Primary Crusher
The sampling data (Plant A, run 1) show two emission rates for
respirable particulates during dumping to the primary crusher:
Q1 « 3.235 x 10~3 g/s for 2 dumps
Q2 = 2.273 x 10~3 g/s for 1 dump
Dividing Q in half to give the emission rate per dump and aver-
aging Qj and Q- gives 1.68 x 10~3 g respirable particulate/s.
Assuming that 25 trucks/hr dump at the primary crusher and that
each truck has a capacity of 32 metric tons, the emission factor
is:
(1.68 x 10~3 g/s)(3,600 s/hr)(hr/25 trucks)(truck/32 metric tons)
EF = 1Q3 g/kg
= 7.56 x 10~6 kg respirable particulate/metric tons
Emissions due to dumping at the primary crusher are assumed to
be similar to emissions from secondary crushing; thus they have a
R/T ratio of 0.036. The emission factor then for total particu-
lates for dumping to the primary crusher is:
EF = 7.56 x 10~"6/0.036 = 2.1 x 10"1* kg total particulate/metric ton
43
-------
Vehicular Movement on Unpaved Roads
During a sampling run of secondary crushing operations (Plant B),
one truck passed, creating an emission due to vehicular movement
on an unpaved road. This emission rate may be determined from
the secondary crushing data by averaging the emission rates (ex-
cluding the run during which the truck passed) and subtracting
this average from the emission rate which includes that run. The
difference is the vehicular movement emission rate:
6.61 x 10"2 g/s - 4.84 x 10~2 g/s = 1.77 x 10~2 g respirable particulate/s
The emission factor can be calculated by assuming that 8 trucks
or loaders are in operation on dry unpaved roads for one hour and
that the ratio of respirable particulate to total particulate
(R/T) is comparable to the R/T ratio for vehicular movement on
wetted roads in a crushed stone plant (0.176). The emission rate
for total particulates is calculated as 1.01 x 10'1 g/s. The
emission factor for total particulates is:
EP - (1.01 x lO"1 g/s truck)(8 trucks)(3,600 s/hr) (10~3 kg/g)
:(650 tons/hr)(0.9078 metric tons/ton)
= 4.91 x 10~3 kg total particulate/metric ton
Similarly/ the respirable particulate emission factor is
8.64 x lO'4 kg/metric ton.
Total and respirable particulate emission factors for each source
and the respective R/T ratio are tabulated in Table B-5. The
overall emission factor for total particulates is 1.07 x 10"1 kg/
metric ton. Similarly, the overall emission factor for respir-
able particulates is 1.53 x 10~2 kg/metric ton.
TABLE B-5. EMISSION FACTORS AND R/T RATIOS FOR PARTICULATE
Total,Respirable,
Source kg/metric ton R/T kg/metric ton
Blasting
Drilling
Secondary crushing
and screening
Dumping to primary
crusher
Vehicular movement
on unpaved roads
TOTAL
7.96 x ID"2
3.99 x 10-*
2.2 x 10~2
2.1 x 10-1*
4.91 x 10-3
1.07 x 10-1
0.169
0.10
0.036
0.036
0.176
0.143
1.35 x 10-2
3.99 x lO-5
8.58 x 10~k
7.56 x 10-6
8.64 x 10-"
1.53 x 10-2
44
-------
COMPOSITION
The emissions from both plants were analyzed (6) for free silica,
fibers, and trace elements. Fiber analysis of emissions from
crushed granite operations is presented below.
Dust Samples from Granite Quarries
Table B-6 shows elemental analyses of dust samples from crushed
granite quarries.
TABLE B-6.
ELEMENTAL ANALYSIS OF DUST
SAMPLE FROM GRANITE QUARRIES
Weight percent
Plant A
Plant B
Element Run 1 Run 2 Run 1 Run 2
Plant A
Blasting
Si
Fe
Al
Ca
Na
Mg
Ti
Mn
Pb
Ga
Cr
V
Cu
Zr
Ag
ib
«
K
5-10
5-10
4
0.7
1
0.2
0.02
0.004
0.002
0.004
0.004
N.D.
N.D.
2-3
4-5
vL3
5-10
5-10
4
2
1
0.3
N.D.a
0.004
0.002
0.01
0.002
0.01
N.D.
3-4
3-4
-vll
5-10
5-10
4
3
1
0.2
N.D.
N.D.
N.D.
0.02
0.08
0.01
N.D.
0.01
5-6
*7
5-10
5-10
3
5
0.8
0.5
N.D.
N.D.
N.D.
0.01
N.D.
0.1
N.D.
0.01
-vlO
*10
>10
>10
4
1
3
0.2
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
0.04
4-5
•vll
^20
aNot detected.
Semiquantitative estimates (±50%) by XRF.
XRF measurements were performed directly
on the filters. Emission spectrographic
analyses were performed on loose participates
from the filters.
45
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Free Silica Analysis from Crushed Granite Quarries
Table B-7 presents the results of free silica analysis of
respirable emissions from crushed granite quarries.
TABLE B-7. FREE SILICA ANALYSIS FROM CRUSHED GRANITE
QUARRIES TAKEN ON THE RESPIRABLE EMISSIONS
Sample source
Plant A
Plant A
Plant B
Free silica,
percent
33.3
30.1
19.6
Mean value (Plants A and B): 27.7%
Standard deviation: 8.56%
Fiber Analysis of Emissions from crushed Granite Operations
A fiber is a particle greater than 5 ym in length with a L/D of
3 or greater.
Field area = 0.005 mm2
Count - 100 fields
Average count/field (Plant A, blasting) = 0.12
Ground level concentration (x = 701 m, y = 0,
and z = 70 m from the source) = 0.03 fibers/mJl
Emission factor for fibers = 3.13 x 109
fibers/metric ton
The mean source severity due to fiber emissions is 0.454 and the
population affected by representative plant emissions with a
severity of 0.1 is 227 persons, as calculated in Appendix C.
46
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APPENDIX C
SOURCE SEVERITY AND AFFECTED POPULATION
TOTAL PARTICULATES
Source Severity
Maximum source severity for total particulates (6) is given as
s . 4.020 Q
D1.814
where S = maximum source severity
Q = emission rate, g/s
D = representative distance from the major source,
(as defined in Section 4), m
The emission rate for total particulates from the representative
plant is estimated as
Q = 454 metric tons/hr x 0.107 kg/metric ton
x 1 hr/3,600 s x 1,000 g/kg
=13.5 g/s
Substituting the values of Q and D into Equation C-l, the
severity for total particulates is
c _ (4,020) (13.5) = Q_3J
(410)1-81*
Affected Population
The affected population is defined as the population between
plant boundaries and a maximum source severity (6) of 0.1.
xs =r/vr w) (c-2)
where x = distance from plant boundaries, m
l/i.i
x.
s=o.i L o.i
7
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1,450 m
XS=1.0 ~ L 1.0 J
= 407 m
Since the plant boundary is 410 m from the major source, the
affected area is
A = ir(l,4502 - 4102) = 6.1 km2 (C-3)
For a representative population density or 100 persons/km2, the
affected population is 610 persons.
FREE SILICA
Source Severity
Source severity for free silica emissions is given as (6)
(C-4)
where TLV is the threshold limit value for dusts containing free
silica, which is given as
TLV - Percent free silica + 2 ^3 = 3.4 x 10-* g/n.3
For free silica in the respirable participates, the emission rate
is 14.3% of the total particulate emission rate,
e _ (316)
(410)1-81lf (3.4 x.10-*
Affected Population
"(316) (13.5) (0.143)11/1'81't
For
^R316) (13.5)(0.143)T
XS L (3.4 x lO-'MS J
S = 0.1, x _ = 10 km
o— U . J.
Since the distance of the plant boundaries is 0.41 km from the
major source, the affected area is
7r(102 - 0.412) = 314 km2
48
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For a representative population density of 100 persons/km2 the
affected population is 31,400 persons.
NITROGEN OXIDES, CARBON MONOXIDE, AND FIBERS
The source severity for nitrogen oxides is calculated from
Equation C-5 (6) .
m 22,200 Q ( ,
N0x Dl?"
The emission rate for nitrogen oxides from the representative
plant is estimated as
Q = 454 metric tons/hr x 2.85 g/metric ton x 1 hr/3,600 s
= 0.359 g/s
The source severity is thus 0.089 at 410 m, and the affected popu-
lation is zero. Severity for carbon monoxide is calculated from
Equation C-6 (6) .
s - 44'B 0 fc-6>
sco - -^nr (c 6)
The carbon monoxide severity is 1.7 x 10"u at 410 m, and the
affected population is zero.
Source severity for fibers is calculated from Equation C-4, as
described earlier.
Sp -- 316-2 - (C-4)
TLV • D1'81**
Using an emission factor of 3.13 x 109 fibers/metric ton for the
454 metric ton/hr representative plant, and using the TLV for
asbestos fibers of 5 fibers/cm3, the severity is thus 0.454.
The affected population is found by computing the affected area
and multiplying by the representative population as follows:
x = I" 316 0 11/1. Bit
xs UTLvTTsTj |U ' ' '
For
S = 0=1, xg = 0.944 km
Since the distance of the plant boundaries is 0.41 km from the
major source, the affected area is
49
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. -, v-.<
w(0.944* - 0.444) * 3.27
. - a.«,_ • , *Ww»!p "iQ*
is 227 p«7»oiui.
50
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GLOSSARY
ANFO: Ammonium nitrate and fuel oil mixture used as an explosive.
azimuth: Horizontal direction expressed as the angular distance
between the direction of a fixed point (as the observer's
heading) and the direction of the object.
cone crusher: Vertical shaft crusher having a conical head.
confidence interval: Range over which the true mean of a popula-
tion is expected to lie at a specific level of confidence.
criteria pollutant: Pollutant for which ambient air quality
standards have been established.
dustiness index: Reference used in measuring the amount of dust
settled where a material is dropped in an enclosed chamber;
specifically, it is a measure of the mass of respirable dust
adhering to 2.2 kg of material.
emission burden: Ratio of the total annual emissions of a
pollutant from a specific source to the total annual state
or national emissions of that pollutant.
fibrosis: Abnormal growth of fibrous connective tissue in an
organ.
field area: Microscopic area examined for fiber content.
free silica: Crystalline silica defined as silicon dioxide
(Si02) arranged in a fixed pattern (as opposed to an
amorphous arrangement).
granite: Very hard igneous rock, usually gray or pink, consist-
ing chiefly of crystalline quartz, feldspar, and mica.
gyratories: Crushers that move in a circular or spiral path.
hazard factor: Measure of the toxicity of prolonged exposure
to a pollutant.
jaw crushers: Crushers that give a compression or squeeze action
between two surfaces.
51
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lignin sulfonates: Organic substances forming the essential part
of woody fibers introduced into the sulfonic group by treat-
ment with sulfuric acid.
limestone: Rock consisting mainly of calcium carbonate.
noncriteria pollutant: Pollutant for which ambient air quality
standards have not been established.
precipitation-evaporation index: Reference used to compare the
precipitation and temperature levels of various P-E regions
of the United States.
processing plant: That portion of the quarry where the operation
of crushing and size classification of stone occurs.
pulverizer: Crusher used to reduce stone size into powder or
dust.
quarry: Term used to refer to the mining, processing plant, and
material transfer operations.
representative source: Source that has the mean emission
parameters.
respirable particulates: Those particles with a geometric mean
diameter of <7 vim.
rock: Stone in a mass.
scalping screen: Screen used to prescreen the feed to crushers.
severity: Hazard potential of a representative source defined as
the ratio of time-averaged maximum concentration to the
hazard factor.
shortheads: Refers to a cone crusher.
shuttle conveyor: Conveyor used to move crushed stone back and
forth between operations.
silicosis: Diffuse fibrosis of the lungs caused by the chronic
inhalation of silica dust <10 ym in diameter.
sizing screen: Mesh used to separate stone into various sizes.
stone: Hard, solid, nonmetallic mineral matter of which rock is
composed.
thixotropic: Relating to a property of gels to become .liquid
when shaken or disturbed.
52
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