United States
             Environmental Protection
             Agency
             Industrial Environmental
             Research Laboratory
             Cincinnati OH 45268
EPA-600/2-78-004e
April 1978
             Research and Development
&EPA
Source Assessment:
Crushed Limestone,
State of the Art

Environmental Protection
Technology Series

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                RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology.  Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:

      1.   Environmental  Health Effects Research
      2.   Environmental  Protection Technology
      3.   Ecological Research
      4.   Environmental  Monitoring
      5.   Socioeconomic Environmental Studies
      6.   Scientific and Technical Assessment Reports (STAR)
      7.   Interagency  Energy-Environment Research and Development
      8.   "Special" Reports
      9.   Miscellaneous Reports

This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of oollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                                EPA-600/2-78-004e
                                                April 1978
                SOURCE ASSESSMENT:
                 CRUSHED LIMESTONE
                 State of the Art
                        by

P. K. Chalekode, T.  R.  Blackwood,  and S.  R.  Archer

           Monsanto  Research Corporation
                1515 Nicholas Road
                Dayton, Ohio  45407
              Contract No.  68-02-1874
                 Project Officer

                  John F. Martin
     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 Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or
recommendation for use.
                               11

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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
increasingly more  efficient  pollution control methods.be used.
The Industrial Environmental Research Laboratory - Cincinnati
(lERL-Ci) assists  in  developing and demonstrating new and
improved methodologies that  will meet these needs both effi-
ciently and economically.

This report contains  an assessment of air emissions from the
crushed limestone  industry.   This study was conducted to provide
a better understanding of the distribution and characteristics of
emissions from crushed limestone 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
                                111

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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, uneconom-
ical, 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 of operations (more than 500) 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 con-
trol technology 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. Binning 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 materi-
als, and open sources.  Dr. Dale A. Denny of the Industrial
Processes Division  at Research Triangle Park serves as EPA Proj-
ect 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
specific 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 pollut-
ants.  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.  However, no extensive
sampling 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 technol-
ogy 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 limestone industry.  This project was initiated by
the Chemical Processes Branch of the Industrial Processes Divi-
sion 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,
under Mr. John F. Martin.
                                v

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                             ABSTRACT,


This  report  describes  a  study  of  air pollutants emitted by  the ,
crushed  limestone  industry.  The  potential environmental  effect '
of, the source  was  evaluated  using source  severity  (defined-as the
ratio of the maximum ground  level concentration of an emission to
a  hazard factor).
       •                    ,                              '•.,,••* ..'.'*
In 1972,  there were  1,374  crushed limestone processing plants
operating 2,904  quarries in  the United States.  The representa-
tive  crushed limestone plant produces 450 metric tons/hr  and
emits particulates from  several operations, including drilling,
blasting,  transport  on unpaved roads, crushing, screening,  con-
veying,  and  stockpiling.   The  emission factor for total particu-
lates emitted  from the representative plant is 3.5 g/metric ton,
and vehicular  movement on  unpaved roads contributes 66% of  the
overall  emissions.   Approximately 38% of  the respirable particu-
late  emissions originate from  vehicular movement on unpaved
roads, and the respirable  particulate emission factor is  0.6
g/metric  ton.  The hazardous constituent  in the dust is free
silica ,. (1.2% by  weight), prolonged exposure to which may  result
in the development of  a pulmonary fibrosis known as silicosis.
Nitrogen  oxides  and  carbon monoxide are emitted by the blasting
operation, but the emission  factors  (and  source severities) for
these emissions  are  small  in comparison to those of particulate
emissions.

The maximum  source severity  for particulates is calculated  as
0.032.  The  affected population is defined as the population
living beyond  the  plant boundary  where the severity is 0.1  or.   \
greater.    The  population affected by a severity of 0.1 due  to
total particulate  emissions  is thus zero.  Similarly, the source
severity due to  free silica  in the respirable particulate emis-
sions is  0.12, and the population affected by a severity  of 0.1
is  11 persons.   The  emissions  from the crushed limestone  industry
(as well as  the  output of  the  industry) are estimated to  be the
same  in 1978 as  they were  in 1972.                             :

This  report  was  submitted  in partial fulfillment of Contract
68-02-1874 by  Monsanto Research Corporation under the sponsorship
of the U.S.  Environmental  Protection Agency.  The study covers
the period August  1975 to  February 1976.
                                VI

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                            CONTENTS
Foreword	iii
Preface	iv
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	 7
            Geographical distribution 	 8
   4:.  Emissions	10
            Selected pollutants '	 . .10
            Characteristics	10
            Definition of representative source ....... .11
            Source severity	13
   5.  Control Technology	16
            State of the art	16
            Future considerations	16
   6.  Growth arid Nature of the Industry	20
            Present technology	,20
            Emerging technology 	 f ,20
            Production trends	20
               /
References	22
Appendices

   A.  Literature survey	25
   B.  Sampling details and results	31
   C.  Source severity and affected population	46

Glossary	49
                               VII

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                             FIGURES


Number                                                       Page

   1    Simplified flowsheet for lime and limestone products.  .6
                             TABLES


   1    Mass Emissions from Various Operations in the
          Crushed Limestone Industry  	 4

   2    .Crushed Limestone Sold or Used by Producers in the
          United States in 1972, by State and Respective
          Population Density 	 9

   3    State and Nationwide Particulate Emission Burdens
          from Crushed Limestone 	12
   4    Pollutant Severity Equations  	15

   5    Source Severity and Affected Population for Emis-
          sions from the Crushed Limestone Industry	15
                               Vlll

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                    ABBREVIATIONS AND SYMBOLS

A          — cross-sectional area of the falling granules, cm2
a. . .d, f -- variable exponents and coefficients used in numer-
                ous methematical manipulations
B          — width of conveyor belt, cm
CHI        — measured concentration less background, yg/m3
D          — representative distance from the major source, m
D          — total dose, g-s/m3
e          — natural logarithm base, 2.72
E          — emission factor, g/metric ton
E          — function of five variables that influence dust
                emissions from drilling operations
F          — hazard factor, g/m3
G          — gravitational acceleration, 980 cm/s2
H          — height of material fall, cm
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 (Equations 1 and 2)
Qn         — 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
SQ. • -Si).  — high-volume sampler locations
TLV        — threshold limit value, g/m3
u          — 4.5 m/s (approximate U.S. average wind speed)
UD         — linear speed of the conveyor belt, cm/s
 D
x          — downwind distance
x., y.     — Cartesian coordinates used to relate position of
 1   1          the ith sampler to the source
                               IX

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                    ABBREVIATIONS AND SYMBOLS

X, X.      — downwind distance from source along the dispersion
                centerline
x          — crosswind distance from the line source, m
 c                   •       .             ~   '  '  v..
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
                position, rad             <
9          — wind azimuth angle with respect to the y axis, rad
TT          — a constant, 3.14
"pc         — material density of coal, g/cm3
a          — overall standard deviation, m
0        '  — horizontal standard deviation of plume dispersion, m
a          — vertical standard deviation of plume dispersion, m
 Z
a T        — instantaneous vertical dispersion parameter, m
 Z _L '
X          — ground level concentration, g/m3
X-         — ground concentration at coordinate location (X.,
 1              Y±, 0), g/m3                                1
X          — maximum ground level concentration, g/m3
 max
X~          — maximum time-averaged ground level concentration,
 max            g/m3
ijj          — dose, g-s/m3

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            CONVERSION FACTORS AND METRIC PREFIXES9
  To convert from

 Centimeter
 Centimeter2, (cm2)
 Centimeter3 (cm3)
 Kilogram  (kg)
 Kilogram  (kg)
 Kilometer2  (km2)
 Meter  (m)
 Meter2  (m2)
 Meter3  (m3)
 Meter 3; (m3)
 Metric, ton
 Radian  (rad)
                      CONVERSION FACTORS
                      To
                                Multiply by
Foot
Inch2
Inch3
Pound-mass
Ton (short.
Mile2
Toot
Foot2
Foot3
Gallon (U'.S
Pound-mass
Degree (°)



(avoirdupois)
2,000 Ib-mass)




. liquid)


3.281 x 10~2
1.550 x ID"1
6.102 x 10~2
2.204
1.102 x 10~3
3.860 x 10-1
3.281
1.076 x 101
3.531 x 101
2.642 x 102
2.205 x 103
5.730 x la1
Prefix   Symbol
 Kilo
 Centi
 Milli
 Micro
k
c
m
     ., METRIC PREFIXES

Multiplication factor

        103
        lO-2
        10~3
        10-6
                                      Example
1 kg
1 cm
1 mm
1  m
1 x 103 grams
1 x 10~2 meter
    10~3 meter
       r*
                                      mt*. •*». J- \S   J.ll>_~ ^.^,^.

                                    = 1 x 10~6 meter
= 1 x
Metric 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 occuring limestone to a crushed form
involves mining from open quarries and processing at finishing
plants.  The mining and processing operations create air pollu-
tion problems.

An investigation of crushed limestone operations was conducted to
provide a better understanding of the distribution and character-
istics of emissions from these activities than had been previously
available in the literature.  Data collection emphasized the accu-
mulation of sufficient information to ascertain the need for devel-
oping control technology in this industry.

This document contains information on the following items:

   • A method to estimate the emissions due to crushed
     limestone processing

   • Composition of emissions

   « Hazard potential of emissions

   • Geographical distribution and source severity

   • Trends in the crushed limestone industry and
     their effects on emissions

   • Type of control technology used and proposed

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                            SECTION 2

                             SUMMARY
The crushed limestone industry converts naturally occurring  lime-
stone deposits to a form that is used predominantly  (67% of  the
output) by the construction industry.  The 1,374 processing
plants, which operate 2,904.quarries in the United States, pro-
duced 6.1 x 108 metric tons  of crushed limestone in 1972.   This
represented 37% of the output of the aggregate industry  (crushed
limestone, granite,$stone, sand and gravel, and sandstone, quartz
and quartzite).  Contingency forecasts of crushed limestone
demands in the year 2000 have been reported to be 1.2 x 109
metric tons to 2.0 x 109 metric tons.

Atmospheric emissions of particulates occur from several unit
operations:  drilling, blasting, transport on unpaved roads,
crushing, screening, conveying, and stockpiling.  The estimated
emission factor available in the published literature, 5.65  grams
of suspended particulate per kilogram of processed material, was
checked by onsite sampling.  The emission factor for total partic-
ulates from crushed limestone processing is 3.5 g/metric ton, and
the emission factor for respirable.particulates is 0.6 g/metric
ton. Total particulate emissions from vehicular movement on
unpaved roads (between quarry and plant) contribute about 66% of
the overall emissions.  Similarly, about 35% of the respirable
particulate emissions are from vehicular movement on unpaved
roads.  The hazardous constituent in the dust is free silica
(1.2% average), prolonged exposure to which may result in the
development of silicosis.

The total national emissions from the crushed limestone industry
account for less than 0.013% of national emissions and less  than
0.07% of any state emissions.

A representative crushed limestone plant produces 450 metric
tons/hr and emits dust at the rate of 0.27 kg/hr respirable
particulates (less than 7 ym) and 1.6 kg/hr total particulates
(less than 100 ym).

To assess the source severity, the ratio of the maximum time-
averaged ground level concentration at the representative plant
 1 metric ton equals 106 grams; conversion factors and metric
 system prefixes are presented in the prefatory material.

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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®) is used which corrects for exposure time and for the
exposure of the general population.  The maximum source severity
due to free silica emissions  (respirable fraction) from a repre-
sentative plant is 0.14.

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 0.089
and 1.7 x 10\ respectively.

Table 1 summarizes the severity and contributions of total partic-
ulates and free silica emissions from the various unit operations.

This  industry is concentrated near limestone deposits, adjacent
to large, rapidly expanding urban areas, and in areas where
largescale public and private works are under construction.  The
distribution of plants with respect to the size of localities
shows that free silica emissions from a representative crushed
limestone plant affect a population of 11 persons down to a
severity of 0.1. The affected population is based on respirable
particulate emissions.

The output of the industry and its emissions are estimated to be
the same in 1978 as they were in 1972.

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 TABLE  1.  MASS EMISSIONS FROM VARIOUS OPERATIONS IN  THE CRUSHED LIMESTONE INDUSTRY
Unit operation
Drilling
Blasting
Loading at
the. quarry
Vehicular
trafficb
Primary
crushing
Primary
screening
Secondary
crushing
Screening
screening
Conveying
Stockpiles
Unloading at
stockpiles
TOTAL0

Emission factors,
q/metric ton
0.11
0.075
0.0015
2.3
0.56
0.0016
0.14
0.0009
0.32
a
_a
3.5
Total
U.S. total,
kg/yr
67 , 000
46,000
9,000
1,403,000
341,000
9,800
85,000
5,500
195,000
_a
_a
2,135,000
particulates
Severity for
Percent representative
of total plant
3 -3
2 -3
_a _a
66 0.021
16 0.005
_a _a
4 0.001
_a _a
9 0.003
_a _a
_a _a
100 0.032
Free silica
Severity for
Percent U.S. total, representative
respirable kg/yr plant
10 80 -a
17 100 -3
0 00
10 1,680 0.05
30 1,240 0.04
30 -a -a
53 560 0.02
53 -a -a
30 700 0.03
-a -a _a
-a .a _a
17 4,360 0.14
 Negligible.
 On unpaved road between quarry and plant.
cTotal may not add to figure shown due to rounding.

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                            SECTION 3

                       SOURCE DESCRIPTION
PROCESS DESCRIPTION

Emission Sources

The conversion of naturally occuring limestone deposits into a
crushed form involves a series of physical operations similar to
those used in the crushed granite and crushed stone industries as
shown schematically in Figure 1.  The deposits are first loosened
by drilling and blasting, then loaded and transported to the
processing plant by trucks or belt conveyors.  Processing
includes such operations as crushing, pulverizing, screening,
conveyi-ng and stockpiling.  After processing, the crushed mate-
rial can be used for construction purposes, or it can be pro-
cessed further for the manufacture of quicklime and of hydrated
lime.

Fine particulate (less than 7 ym) emission sources in the crushed
limestone industry can be divided into two categories:  1)
sources associated 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,
and loading are also fugitive dust sources.

This study is confined to an evaluation of emissions from crushed
limestone processing and does not include those from quicklime or
hydrated lime operations  (Figure 1).

Source Composition

Limestone is a sedimentary rock composed primarily of calcium
carbonate (CaC03) and secondarily of magnesium carbonate (MgCO3),
including varying percentages of impurities.  Limestone is gener-
ally classified into the following types:

   • High-calcium—The carbonate content is composed essen-
     tially of calcium carbonate with a magnesium carbonate
     content of no more than 5%  (usually less).

   • Magnesian—This rock, which contains both carbonates,
     possesses a magnesium carbonate content of 5% to 20%.

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                                      AREA OF STUDY
                                        HIGH-CALCIUM AND DOLOMITIC LIMESTONE
                                             QUARRY AND MINE OPERATIONS
                                           (DRILLING, BUSTING AND CONVEYING
                                                 OF BROKEN LIMESTONE)
                                    1
                              PRIMARY CRUSHER
o
to
>-
on
lu
oS
                         SCREENING AND CLASSIFICATION
                                    I
                                                      152mm TO 203mm
                                                         LIMESTONE
                            jSECONDARY CRUSHING}
                                      -


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   • Dolomitic—This rock contains over 20% MgC03; however,
     the maximum MgC03 content will not exceed 45.6%, the
     exact amount contained in a true, pure, equimolecular
     dolomite, with the balance CaCO3.

Chemical analyses of different,types of U.S. limestones show that
the lime (CaO) content ranges from about 29% to 55%, the magnesia
(MgO) content ranges from 0% to 21%, the alumina  (A1203) content
is less than 6%, and the iron oxide (Fe2O3) content is less than
2%  CD .

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 sourcebysource 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
grams of particulates emitted per metric ton of crushed limestone
processed.

The emission rate for each of the source types is estimated as
the product of the emission factor and the crushed limestone
production rate.  This relationship can be stated as shown in
Equation 1.

                            Q = E(P)                           (1)

where  Q = emission rate of particulates, g/hr

       E = emission factor for particulates, g/metric ton
           of crushed limestone processed

       P = production rate of crushed limestone,
           metric tons/hr

The overall emissions from crushed limestone operations are due
to drilling, blasting, loading, vehicular movement on unpaved
roads (between quarry and plant), 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.

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.  Although estimates of emission
(1) Kirk-Othmer Encyclopedia of Chemical Technology, Second
    Edition, Vol. 12-  John Wiley & Sons, Inc., New York,
    New York, 1969.  pp. 414-423.

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factors for some unit operations are available in the published
literature, no studies were conducted or reported to validate  the
estimated emission factors  (Appendix A).

A sampling of emissions from two crushed limestone plants was
conducted  (see Appendix B for details and results of sampling).
The results show that vehicular traffic on unpaved roads between
the quarry and plant contribute 66% of the total particulate
emissions, and that primary crushing operations contribute 16% of
the overall .emissions.  Similarly, 38% of the respirable par-
ticulate emissions are from vehicular traffic on unpaved roads,
and 28% of the "respirable particulate emissions are from primary
crushing operations.

The factors believed to influence emissions from vehicular move-
ment on unpaved roads are vehicle speed, vehicle weight and
crosssectional area, number of wheels, tire width, particle size
distribution, and moisture content of unpaved road surface mater-
ial. Though considerable information is available on the magni-
tude of unpaved road emissions, little has been done to correlate
the emissions with soil or vehicle characteristics.

GEOGRAPHICAL DISTRIBUTION

In 1972 there were 1,374 crushed limestone processing plants (2)
operating 2,904 quarries (personal communication with W. Pajalich,
Bureau of Mines, Washington, D.C., 15 October 1975)  with a total
total output of 6.1 x 108 metric tons.  Pennsylvania ranked first
with 5.1 x 107 metric tons, followed by Illinois, Florida, Ohio
Texas, Missouri, Michigan,  Tennessee, New York and Kentucky.
Together, these 10 states accounted for 66% of the total crushed
limestone production in the United States (3).

Table 2 gives the crushed limestone output by state in the United
States and the respective population densities.

Geographically, the crushed limestone industry is concentrated
near limestone deposits, adjacent to 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.

                                8

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 TABLE  2.   CRUSHED LIMESTONE SOLD OR USED BY  PRODUCERS
            IN THE  UNITED  STATES IN  1972, BY STATE AND
            RESPECTIVE POPULATION DENSITY
Population density,
State persons/Jon2
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
Wisconsin
Wyoming
Undistributed
TOTAL
27
7
15
50
9
240
49
31
49
4
78
57
20
11
32
12
177
274
60
18
It
27
2
8
2
366
3
145
39
2
102
15
9
103
312
34
2
38
17
5
19
46
29
31
1


Production in 1972,
10 3 metric tons
14,800
2,200
4,700
16,400
3,000
200
48,200
5,600
1,100

51,100
24,500
24,900
12,700
31,100

13,100
800
35,200
4,400
400
37,800
1,300
3,900
2,000

1,300
31,200


43,100
16,400

51,300


1,500
32,400
38,600
2,100
1,100
17,300
9,700
14,300
1,400
7,500
610,000a
Note.—Blanks denote information withheld owing to confidential
       nature of data;  included with "undistributed."

aData  do not add to total  shown due to independent rounding.

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                            SECTION 4

                            EMISSIONS
SELECTED POLLUTANTS

Emissions from crushed limestone operations are classed as nui-
sance particulates.  They are considered to be toxic only when
they contain a toxic component such as free silica  (4, 5).

The prolonged inhalation of dusts containing free silica may
result in the development of a disabling pulmonary fibrosis known
as silicosis.  The action of silica on the lungs results in the
production of a diffuse, nodular, progressive fibrosis that may
continue to increase for several years after exposure is termina-
ted.  The first and most common symptoms of uncomplicated silico-
sis are shortness of breath on exertion and a dry cough.  When
the disease advances, the shortness 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.  Extreme 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 milligrams per cubic meter) of 10/(percent
quartz + 2) for respirable dusts containing quartz or free silica.
Dusts with less than 1% silica are termed "inert," and their
suggested TLV is 10 mg/m3  (5).

CHARACTERISTICS

Mass Emissions

The mean emission factor for respirable particulates is
0.6 g/metric ton of limestone processed through the primary
crusher.  The mean emission factor for total particulates is
3.5 g/metric ton.   Total particulate emissions due to vehicular
(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.

                                10

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movement on unpaved roads between  the quarry and plant  contribute
66% of the overall emissions.  Similarly,  38% of the  respirable
particulate emissions are from vehicular movement on  unpaved
roads.  The foregoing results are  based on a sampling of two
crushed limestone plants  (see Appendix B).  The total particulate
emission factor generated in this  study is less than  the estima-
ted emission factor reported in'literature published  prior to
this study.  The emission factors  for nitrogen oxides and carbon
monoxide, respectively, are 2.85 g/metric ton and 1.68  g/metric
ton (6).

The aforementioned emission factor for total particulates was
used to estimate the statewide emissions from crushed limestone
processing, as shown in Table 3.   The state emission  burden is
calculated as.the percent contribution of total particulate
emission rates from crushed limestone processing in a state to
the overall total particulate emission rates in that  state. Table
3 displays the state and.nationwide burdens.  The emissions of
total particulates due to crushed  limestone processing  contribute
0.07% or less to the overall particulate emissions in each of the
states in the United States.

Composition of Emissions
  h "                            . ^
An analysis of the emissions from crushed limestone operations
(Appendix B) shows that free silica, constituting 1%  to 2% by
weight, is the only known hazardous component.  Remaining con-
stituents are considered! inert.

DEFINITION OF REPRESENTATIVE SOURCE

The size of crushed limestone plants ranges from about  136 metric
tons/hr to 1,090 metric tons/hr with the average of 450 metric
tons/hr being the size of the representative plant (personal com-
munication with F. Renninger, National Crushed Stone Association,
Washington, D.C., 7 November 1975).

The mean emission factor was determined by sampling two crushed
limestone plants whose production rates were similar  to that of
the representative plant (Appendix B).  Thus, the representative
source emits dust at a rate of 0.27 kg/hr respirable particulates
(less .than 7 ym)  and 1.6 kg/hr total particulates.

The representative population density, taken as the average pop-
ulation density of the states weighted on the basis of  their
crushed limestone production, is 58, persons/km2.  The representa-
tive distance from the plant is defined using the major contribu-
ting source within the plant as the reference point.  The

(6)  Blackwood, T. R., P. K. Chalekode, arid R. A. Wachter.
    Source Assessment:  Crushed Stone.  Contract 68-02-1874,
    U.S. Environmental Protection Agency, Cincinnati, Ohio,
    July 1977.  91 pp.

                               11

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       TABLE 3.   STATE AND NATIONWIDE  PARTICULATE  EMISSION
                   BURDENS  FROM CRUSHED  LIMESTONE
    State
Total participate
 emissions from
crushed limestone
processing (1972),
 metric tons/yr
      Overall
    particulate
  emissions (7)
103 metric tons/yr
 Contribution of
crushed limestone
  emissions to
  overall state
  emissions, %
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Florida
Georgia
Hawaii
Illinois
Indiana
Iowa
Kansas
Kentucky
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Mexico
New York
Ohio
Oklahoma
Pennsylvania
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Other states8
TOTAL
52
8
16
57
11
1
169
20
4
179
86
87
44
109
46
3
123
15
1
132
6
14
7
5
109
151
57
180
5
113
135
7
4
61
4
34
50
5
26
2,135
1,179
73
138
1,006
201
40
226
405
62
1,143
748
216
348
546
495
96
706
266
168
202
273
95
94
103
160
1,766
94
1,811
52
410
549
72
15
477
162
214
412
75
1,662
16,762b

0.01
0.01
0.01


0.07

0.01
0.02
0.01
0.04
0.01
0.02
0.01


0.01

0.06


0.01

0.07
0.01
0.06
0.01
0.01
0.03
0.02
0.01
0.03
0.01

0.02
0.01
0.01

0.013C
Note.—Blanks indicate negligible contribution.
 Includes Idaho,  Maine, New Jersey, North Carolina,  North Dakota, Oregon,
 Rhode Island,  and  South Carolina.

 Includes overall particulate emissions from Alaska, Delaware, District of
 Columbia, and  Louisiana, which do not have crushed  limestone plants.

cSince respirable particulate is 14.2% of total  particulate emissions,
 national emission  burden due to respirable particulate emissions from
 crushed limestone  emissions is 0.002%.
(7)  1972  National Emissions Report.  EPA-450/2-74-012,  U.S. Environmental
    Protection Agency, Research Triangle Park, North Carolina, June 1974.
    422 pp.
                                    12

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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 representative plant.  The area of a representative
crushed limestone plant was assumed to be similar  to  that of a
representative crushed stone plant  (0.53 km2),  and the  resulting
representative distance to the plant boundary  is 410  m  (6).

The output of the representative plant and  its  emissions should
follow industry trends; they are estimated  to  be the  same in 1978
as they were in 1972.

SOURCE SEVERITY

The source severity, used to indicate  the hazard potential of the
representative emission source, is determined  using 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)•  F°r open sources, the  model employs the con-
centration of a pollutant occurring at a ground level point
source on the plant boundary.  This is the  maximum concentration
that can occur at one point in time and, thus,  is  considered a
worst-case condition.  The hazard factor is  derived from ambient
air quality criteria or reduced threshold limit values.

Ground Level Concentration

The minimum distance from the major contributing emission source
to the representative crushed limestone plant boundary is 410 m,
as shown in Section 4.  This is the minimum distance  at which
public exposure to the pollutant could occur.

The following formula in conjunction with class C  meteorological
conditions (approximate U.S. average)  was used  to  calculate Xmax
(the maximum ground level, instantaneous concentration) (8):


                          xmax ~ ira a  u


where   Q = mass emission rate, g/s
        TT = 3.14
       a  = 0.209 (x°-903)
       ol = 0.113 (x°-911)
        u = 4.5 m/s  (approximate U.S.  average wind speed)

The instantaneous ground level concentration for total particu-
lates at 410 m is 24 yg/m3.  This must be 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.  84 pp.
                               13

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averaged maximum, Xmax' for 24 hr as described by Nonhebel  (9)  so
that the mean concentration becomes 8.4 yg/m3.  Therefore,  the
maximum ground level concentration at the boundary of the repre-
sentative plant during a 24-hr period is 8.4 yg/m3 above back-
ground levels  (worst case).

Hazard Factor

Since no ambient air quality criterion exists for free silica,
the hazard factor, F, is defined as follows:
                         F 7 2<

The derivation of F utilizes the TLV corrected from 8-hr to 24-hr
exposure with a safety factor of 100 applied to this calculation.
The free silica hazard factor for the purposes of this report is
calculated as 10.4 yg/m3, comparable to that for respirable
emissions since the TLV is for respirable emissions.  For total
particulates, F shall be defined as the 24-hr ambient air quality
standard of 260 yg/m3.

Source Severity

For the representative crushed limestone plant, the maximum
severity is determined from the ratio of the maximum time-
averaged ground level concentration_of the emission species to
the hazard factor for the species (Xmax/F)•  ^e maximum time-
averaged ground level concentration is related to the.mass emis-
sion rate, Q  (in grams per second)  of a pollutant and, for open
sources, to the representative  distance, D, from the source to
the plant boundary.

Using the approach described above, the equations in Table 4 were
used to determine the severity of criteria and noncriteria
pollutants from the crushed limestone industry (10).  The equa-
tions simplify the calculation of both severity and, ultimately,
affected population.

Source severities due to and the population affected by emissions
of criteria and noncriteria pollutants from the crushed limestone
industry are shown in Table 5.  Severity can also be obtained by
calculating the ratio Xmax/F-  Thus for particulate (Xmax equals
8.4 yg/m3 and F equals 260 yg/m3),  the severity is 0.32.  Sample
calculations for source severity and affected population are
provided in Appendix C.

 (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, Cincinnati, Ohio, July 1977.  96 pp.

                               14

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             TABLE 4.  POLLUTANT SEVERITY EQUATIONS


                                         Severity
             _ Pollutant _ equation
             Particulate              S =  'p,               (4)
                                           U •*• » O •"•


             Nitrogen oxides          S = 22'?°9flQ             (5)
                                            jj i . 3 U


             Carbon monoxide          S = 44;80?               (6)
                                           D i * o i
             Noncriteria pollutant    S =                      (7)
     TABLE 5.  SOURCE SEVERITY AND AFFECTED POPULATION FOR
               EMISSIONS FROM THE CRUSHED LIMESTONE INDUSTRY
Type of pollutant
Total particulates
Free silica
Nitrogen oxides
Carbon monoxide
Source
severity
0.032
0.14
0.089
0.00017
Affected
population9
0
11
0
0

     Population affected down to a severity of 0.1.

Since the maximum source severity for total particulates is less
than 0.1 at the plant boundary {Appendix C) , the affected popu-
lation is zero.  Similarly, the maximum source severity for free
silica in the respirable particulates is 0.14 and, for a repre-
sentative population density of 58 persons/km2, the population
affected by a severity of 0.1 is 11 people residing within 0.49
0.49 km from the plant boundary.  The maximum source severities
for nitrogen oxides  (NOX) and carbon monoxide (CO) from blasting
are 0.089 and 0.00017, respectively, with zero affected
population.
                               15

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                            SECTION 5

                       CONTROL TECHNOLOGY
STATE OF THE ART

Many plants control emissions from unpaved roads by frequently
spraying the roads with water or oil.  Some plants use a wet
suppression system and/or baghouse to suppress dust emissions
from crushing, screening, and conveying operations.

Dust generated from various operations is dependent upon the dry-
ness of the handled material; hence, any method used to add mois-
ture is helpful in controlling dust levels.  Natural phenomena
such as rain or snow and in-process washing or spraying opera-
tions are good examples of methods for controlling dust.

FUTURE CONSIDERATIONS

The fugitive and point sources of dust limestone processing are
drilling, blasting, loading, unpaved road transport, crushing,
screening, conveying, and stockpiling.

Dust emissions from dry percussion drilling operations can be con-
trolled by adding water or water mixed with a surfactant to the
air used for flushing drill cuttings from the hole.  Dilution
ratios range from 800 to 3,000 parts of water to 1 part surfac-
tant.  An 89-mm-diameter hole requires 0.026 m3/hr of solution.
This permits the drill cutting to be blown from the hole as damp,
dust-free pellets (11).

In conventional coal mining, 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.  Such pastes are gelatinous in repose but liquefy
when disturbed.  A similar control method may be applicable for
reducing particulate emissions from blasting in limestone 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
     Quarrying.  Air Engineering, 10(25):21, 1968.

                               16

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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 properly carrying out the detonation to prevent
incomplete combustion.

Loading of the blasted limestone 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 or 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
emissions (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
cqst of approximately $0.15/m2 treated per year (14).  The major
problems involved in its use are the corrosion of vehicle bodies
and leaching by rainwater 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 0.009 m3/m2
of the road surface.  Certain pretreatment measures such as
working the road surface into a stiff mud are necessary to pre-
vent 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 EPA-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

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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 effi-
cient method of controlling unpaved road dust emissions.  The
cost for such applications is estimated to be $0.10/m2 treated
per year (11).   However, a study conducted in New Jersey shows
that 70% to 75% of the oil applied moves to the surrounding
ecosystem from the surface of the road 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
sulfonate9 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 its high cost and the temporary
nature of crushed limestone 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.  A crushed rock
production plant uses a dust suppression system^ and a chemical
wetting agent.  Approximately 0.004 m3 of the concentrated wet-
ting 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 0.0042 m3 of solution per
metric ton of material being crushed.  This system also helps in
 Orzan A.,  supplied by Crown-Zellerback 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 Protec-
     tion 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.


                               18

-------
reducing dust emissions at transfer  points,  screening  operations,
storage bins, and stockpiling operations  (19).   Such a system has
many cost-saving advantages.  It  requires  no ducts, hoods,  or
other enclosures for crushers,  screens, or conveyors.   The
equipment is in the open and allows  the operators  to see  the
entire material flow.  Dust is  not collected,  and  there are no
solid waste disposal or water pollution problems.

In a crushed stone plant  (with  processes similar to those of  a
crushed limestone plant), a baghouse is used to  control dust
emissions from cone crushers, scalping screens,  and twin  sizing
screens, and at the 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 presents  a  solid waste prob-
lem.  The alternative disposal  methods are to  put  the  dust  into
settling basins or to develop sales  opportunities.  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 Experi-
     ment to Transfer Technology to the Crushed Stone Industry.
     Contract NSF-C826, National Science Foundation, June 1974.
     50 pp.

                               19

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                            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 impact crushers.  Second-
ary crushing is done by cone crushers or impact crushers.  The
crushed limestone is screened and sent to open area storage.

EMERGING TECHNOLOGY

This study did not reveal emerging technology of specific impor-
tance to air pollution control in the crushed limestone industry.

PRODUCTION TRENDS

Production of crushed limestone is tied closely to the product
consuming industries.  Since the construction industry consumes
more than 67% of the output, the production of crushed limestone
is associated chiefly with the needs of this industry (3).  Pro-
duction of crushed limestone was 6.1 x 108 metric tons in 1972.
In 1973, 7.0 x 108 metric tons and in 1974, 6.;8 x 108 metric tons
of crushed limestone were either shipped to or used by producers
in the United States (22).

Assuming the same annual growth rate as that for the crushed
stone industry (3.5% to 5.1%), the contingency forecast of
crushed limestone demand in the year 2000 is 1,200 to 2,000 x 106
metric tons.

Transportation constitutes a major part of the delivered cost of
crushed limestone.  These costs may exceed the sales value of the
material at the processing plants, which are therefore located
near the point of use.   Local zoning and environmental regula-
tions and depletion of urban deposits may necessitate the loca-
tion of future plants much farther from the point of use.  This
should increase the use of rail and barge systems to hold down
transportation costs.  Truck haulage will remain important,
(22)  Mineral Industry Surveys.  Annual Advance Summary.  U.S.
     Department of the Interior, Washington, D.C., September 17,
     1975.  12 pp.

                               20

-------
especially for local delivery of crushed products, despite the
use of rail and water transportation for long distances to
central distribution points.  These factors will undoubtedly
result in an increase in the delivered price of crushed
limestone.
                                21

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                           REFERENCES
 1.  Kirk-Othmer Encyclopedia of Chemical Technology, Second
     Edition, Vol. 12.  John Wiley & Sons, Inc., New York, New
     York, 1969.  pp. 414-423.

 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. J.  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.
     Department 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, Cincinnati, Ohio, July 1977.  96 pp.

11.  Jones, H. R.  Fine Dust and Particulates Removal.  Noyes
     Data Corporation, Park Ridge, New Jersey, 1972.  307 pp.


                                22

-------
12.  Grossmueck, G.  Dust Control in Open Pit Mining and Quarry-
     ing.  Air Engineering, 10(25):21,  1968.

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. Bailee, 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.

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 Experiment
     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. 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.
                                23

-------
24.   J. C. Ochsner, P. K. Chalekode, and T. R. Blackwood.  Source
     Assessment: Transport of Sand and Gravel.  Contract 68-02-
     1874, U.S. Environmental Protection Agency, Cincinnati,
     Ohio, October 1977.  63 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
     Dust Sources.  EPA-450/3-74-037,  U.S. Environmental Protec-
     tion Agency, Research Triangle Park, North Carolina, June
     1974.  172 pp.

27.   Blackwood, T. R., R. 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 Continu-
     ous Functions of the Lateral  and  Vertical Atmospheric Disper-
     sion Coefficients.  Atmospheric Environment,  6 (11) :859-863,
     1972.

31.   Gifford, F. A., Jr.  An Outline of Theories of Diffusion in
     the Lower Layers of the Atmosphere.   In:   Meteorology and
     Atomic Energy 1968, Chapter 3, D. A. Slade, ed.  Publication
     No. TID-24190, U.S. Atomic Energy Commission Technical
     Information Center, Oak Ridge, Tennessee, July 1968.  pp.
     65-116.

32.   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, Minne-
     sota, 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:  t,
dependent on the material and those dependent  on the ope.   ion.
Material-dependent parameters, generally the same for  all o; ••-
ations, are moisture content, density, and "dustiness  index,
which will be defined as the mass of respirable dust adhering  CL
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 emis-
sions from different materials undergoing the  same operation.
Parameters dependent on the operation are as varied as the  opera-
tions themselves.

DRILLING AND BLASTING OPERATIONS

The following factors influence the dust emissions from drilling
operations:

          1)   Number of bits

          2)   Sharpness of the bits

          3)   Speed of the bits

          4)   Depth of bit penetration

          5)   Experience of the machine operator

The literature search neither yielded quantitative data nor indi-
cated a relationship between the emission factor (ED)  and the

                               25

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aforementioned factors.  A qualitative relationship might possi-
bly resemble

                                (1)(3)                       ,   ,;
                          ED a (2) (4) (5)                     (A  ±}

where the numbers in parentheses represent functions of the
respective variables shown above.

Of all the unit operations, dust emissions from blasting have
been studied the least.  The literature search yielded a poten-
tial list of factors influencing emissions:  frequency of blast-f
ing, bulk moisture content of the rock, particle size distribu-
tion, type and amount of explosive, and hole size.

Studies have been conducted on the magnitude 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 and should yield more carbon monoxide
than carbon dioxide.  Conversely,  a lower percentage of fuel oil
should not produce carbon monoxide and 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
kilogram of ANFO and 1.3 m3 of CO per kilogram of ANFO, while 6%
fuel oil results in 0.32 m3 of NOx per kilogram of ANFO and 1.8 m3
of CO per kilogram 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).

CONVEYING OPERATIONS

Dust emissions from conveying operations come from wind-blown
dust during open conveying and conveyor discharge.
(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.
                          i,   '
(24)  J.  C.  Ochsner,  P.  K.  Chalekode, and T. R. Blackwood.  Source
     Assessment:  Trnasport of Sand and Gravel.  Contract 68-02-
     1874,  U.S. Environmental Protection Agency, Cincinnati, Ohio,
     October 1977.  63  pp.

                               26

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Emissions from conveyor discharge and parameters  affecting  these
emissions were evaluated by Cheng  (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
measured by a Soiltest Speedy Moisture Tester.  Cheng found the
following relationship:
                   R=  8'5° X


where   R = specific  formation of airborne respirable dust, g
       _A = cross-sectional area of the falling granules, cm
       PC = material  density of the coal, g/cm*
        G = gravitational acceleration, 980 cm/s2
        H = height of fall, cm
        M = belt  load,  g/cm2
        B = width of  the conveyor belt, cm
       UR - linear speed of the conveyor belt, cm/s

Cheng concluded the following:

    • About 10% of the adhering respirable dust becomes air-
     borne 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 much greater
     than 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 factor, E, for unloading
operations, based on  milligrams of suspended dust particles less
than 30 ym in diameter  per kilogram of aggregate unloaded, obeyed
the following relationship:

                      _ 20 mg of particulate                ra-^
                           kg of aggregate                  (A J)
 (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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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 Appendix A, "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 needs to be  applied to
make the equation applicable to all conveying and unloading
operations.

OPEN STORAGE

Emissions due to open storage have been discussed in detail  in
previous documents (10, 26, 27).

LOADING OPERATIONS

Emissions from loading operations occur in the transfer of mater-
ial 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 arises from the
scooping and 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

          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
(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

-------
                         R 0  (D(3)(6)                       (A_4)
                         K tt  (2) (4) (5)                       (A 4;

where each number in parentheses represents  a  function  of  its
respective parameter as listed above.

Dust emissions from scooping  operations are  more difficult to
define because relevant information was not  available.   However,
the following factors are believed to play a large part in deter-
mining emissions from this source:

          7)   Density of material

          8)   Moisture content of material

          9)   "Dustiness index" of material

          10)   Degree of storage pile disturbance rendered by
               the scooping machinery

Although  there is no basis for determining a relationship  between
these variables and respirable dust formation, R, a qualitative
relationship might possibly resemble

                              (7) (9) (10)                      ,  5)
                         R a     (8)                          (A b)

where each number in parentheses represents  a  function  of  its
respective parameter as shown above.

Although  not applicable to the determination of R, it has  been
found  (25) that the emission  factor, E, which  can be expressed as
milligrams of dust less than  30 ym in diameter emitted  per kilo-
gram of material loaded for loading crushed  limestone at an
asphalt plant is represented  by

                     ? -     25 mg of dust                    .
                         kg of material loaded

E was  believed  to vary with  the P-E Index of the area considered.

CRUSHING/GRIND ING/SIZING OPERATIONS

Emissions  from  crushing, grinding, and sizing operations are  the
result of  respirable dust formation during size reduction and
crusher or screen discharge.

The factors affecting discharge emissions are the  same as those
for conveyor and power shovel discharge  (see "Conveying Opera-
tions" and "Loading Operations" sections) .

Dust emissions  from size reduction are judged to be  influenced
by
                               29

-------
          1)   "Dustiness index" of material

          2)   Moisture content of material

          3)   Degree of particle-size reduction

          4)   Rate of material flow through size reducer

A qualitative expression for respirable dust formation, R,  is
believed to be
                           R a    (3)                        (A_7)
                           R a (2) (4)                        (A 7)


where each number in parentheses 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" section for a quantitative evaluation
of air flow induced by discharge.)

High-speed pulverizers create air flow during both size reduction
and discharge.  Air flow induced by high-speed size reduction may
be inferred from the literature to be inversely proportional 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

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                            APPENDIX B

                   SAMPLING DETAILS AND RESULTS3


 SAMPLING SITE DESCRIPTION

 The  purpose of the sampling was to obtain data on the overall
 plant  emissions and the relative contributions of the various
 unit operations.

 Two  crushed limestone plants were chosen whose operations  were
.representative of the crushed limestone industry.   In addition,
 these  plants were located in areas with favorable meteorological
 conditions  for sampling.

 Plant  A

 Mining—
 At the blasting site, holes are drilled in the rock in a circular
 pattern and then charged  with ANFO and dynamite.   Blasting is
 carried out 12 times per  month at this mine.   The yield is 2,700
 metric tons of limestone  rock per shot.   The  rock is loaded into
 20-metric ton haul trucks by a front-end loader and transported
 on an  unpaved road to a primary crusher and a scalping screen.

 Process Plant--
 The  scalping screen is a  1.22 m x 1.83 m vibrating screen,  and
 it separates material less than 80 mm in size.   The oversized
 material is fed to a Cedar Rapids 4350S double impeller impact
 crusher which crushes the feed to less than 80 mm size.  Under-
 sized  material from the scalping screen and crushed material from
 the  primary crusher are conveyed to screens arranged in series.

 The  first screen is a 1.22 m x 3.66 m, two-deck screen that
 separates the material into three sizes:  greater than 64  mm,
 44 mm  to 64 mm,  ai^ less  than 44 mm.   The oversized material from
 the  screen  may be stockpiled or crushed again in a Universal
 impact crusher and reconveyed to the screen.

 The  undersized material from the first screen goes to a 1.22 m x
 4.27 m,  three-deck horizontal screen that separates the feed into
 three  sizes:   19  mm to 44 mm, 6 mm to 19 mm,  and less than 6 mm.
aNonmetric units  appear  in  this  appendix  because  they  were  used
 in the original  work.

                               31

-------
The products are stored in bins or stockpiles and  loaded,  into
trucks for shipment to customers.

The plant operates for 8 hr/day and the average processing  rate
through the primary crusher is 190 metric tons/hr.  The number of
days of operation in a year depends on both the demand for  the
product and the functioning of the equipment—usually about 6 mo
to 8 mo/yr at 5 days/wk.

Plant B

Mining—
The mining activities are similar to those at plant A.

Process Plant—
The scalping screen is a 1.22 m x 2.44 m vibrating screen which
separates material less than 100 mm in size.  The oversized
material is fed to a 1.07 m x 1.22 m Lippman jaw crusher which
crushes the feed to less than 100 mm size.  The undersized  mater-
ial from the scalping screen and the crushed material from  the
primary crusher are conveyed to a 1.52 m x 3.66 m horizontal
screen.  This screen separates the material into less than  50-mm
and greater than 50-mm particles.  The oversized material
 (greater than 50 mm) goes through two shorthead cone crushers.
The undersized  (less than 50 mm)  material and the material  from
the cone crushers are conveyed to a 1.83 m x 4.88 m, three-deck
horizontal screen.  This screen separates the material into three
different sizes:  19 mm to 50 mm, 13 mm to 19 mm, and less  than
13 mm.  The products are stored in bins or stockpiles prior to
shipment.

The plant operates for 8 hr/day and the average processing  rate
through the primary crusher is 330 metric tons/hr.  The plant
operates for 8 mo/yr at 5 days/wk.

Both plants A and B control emissions from unpaved roads by
spraying the roads with oil.  Sampling data and results are given
later in Tables B-4, B-5, and B-6.

SAMPLING PROCEDURES

Samplers

General Metal Works high-volume samplers8 were positioned around
an area as shown in Figure B-l.  For this arrangement, the  origin
was defined at the source, and all remaining points were defined
in the Cartesian coordinate system.  The angle of mean wind
direction was 6.  The downwind distance of any point y. perpendi-
cular to the wind direction centerline was computed in1the  follow-
ing manner:
9General Metal "'Works,  Inc., 8368 Bridgetown Road, Cleveland, Ohio
 45002.

                               32

-------
                                   WIND AZIMUTH
                                     METEOROLOGICAL STATION
                Figure B-l.  Sampling  arrangement

                             mj ='tan  8

 and  for point S. with coordinates  x., y.,
                                       (B-l)
                              m? = —
                                z   x.
The  angle a was found from
                       a - arctan
                                  1 +
The  lateral distance Y. is
                                       (B-2)
                                       (B-3)
.  = (sin a)
                                                              (B-4)
and the  downwind distance X. is
                      X. =  (cos a)  /xi2 + y±2                 (B-5)


These values  are used in appropriate dispersion models.   The
sampling time for high-volume samplers was  about 4  hr.   Five
different high-volume samplers were used to monitor the  area
emissions at  positions S0, S^, 82/ S3, and  S^.


                                33

-------
A GCA  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 GCA instrument was about
4 min; hence, only one unit was necessary to monitor at  all the
positions (not simultaneously).

The high-volume samplers collect particles less than 100 ym in
size, while the GCA unit collects less than 10-ym particles with
a cyclone separator and less than 50-ym particles without a
cyclone separator.

Models

Open source sampling uses diffusion models in reverse.   It  is
used to predict concentrations surrounding a point source of
known strength.  Several concentration readings are taken to
calculate the source strength of an open source.

Models applicable to the sampling arrangement and source char-
acteristics are chosen and utilized for each emissive source.
Three models are used in this study.  The first represents  emis-
sions from drilling, front-end loading, primary and secondary
crushing, and secondary screening.  This is the point source
model  (8) where
      X  (x, y, z; H) =
                exp
exp
(B-6)
                          z - H
       exp
                 z + H
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 Gaussian distribution in both the
horizontal and vertical planes, with standard deviations of plume
concentration distribution in the horizontal and vertical of a
and az/ respectively; the mean wind speed affecting the plume Is
u; the uniform emission rate of pollutants is Q; and total reflec-
tion of the plume takes place at the earth's surface; i.e.,
there is no deposition or reaction at the surface.  Any consist-
ent set of units may be used.  The most common is x J-n grams per
cubic meter;  Q in grams per second;, u in meters per second; and
 GCA Corporation, GCA Technology Division, Bedford, Massachusetts,
(29)  Lilienfeld,  P., and J. Dulchinos.  Portable Instantaneous
     Mass Monitor for Coal Mine Dust.  American Industrial
     Hygiene Association Journal, 33(3):136, 1972.
                               34

-------
tfy, 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
a's and u are representative.   The values  of  both ay  and az  are
evaluated in terms of the downwind distance,  x, and stability
class.  Stability classes are determined conveniently by graphi-
cal methods, Figure B-2  (27) .   Continuous  functions are then used
to calculate values for  ay and  az, Tables  B-l and B-2, given the
downwind distance, x  (30) .  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 equals 0) ; and the concentra-
tions are calculated at  ground  level.   Equation B-6 thus reduces
to  (8)


                      *  <*' °'  °<- °> =   -                  (B~7)
                                         y  z

The second model  is used to describe emissions from belt convey-
ing and transporting on unpaved roads.   In  this equation, instan-
taneous puff concentrations are described by Equation B-8 (31) :

                               / ? \ 1/2   Qn
                           $ =  £   '  — °_                 (B-8)
                               U }    azlu


where     if/ =  dose, g-s/m3
          QD =  line  source emissions per  length of line, g/m
        azl =  instantaneous vertical dispersion parameter, m
          u =  mean  wind speed, m/s
For neutral  stability,
                         azl =  0.15 xc°-7                     (B-9)
where   x   =  crosswind distance  from  the  line source, m
        IM>

Equation B-8 is  a  line  source diffusion  model and is used to find
the  mass emissions per  length of road or per length of conveyor
belt.   The value of the dose, fy, is  determined by multiplying the
concentration by the actual  sampling time.

The  third  model  is used in computing total dose  from a finite
release in blasting.  This is calculated from Equation B-10  (8):
 (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) Gifford,  F.  A.,  Jr.  An Outline of Theories of Diffusion  in
     the Lower Layers of the Atmosphere.  In:  Meteorology  and
     Atomic Energy 1968, Chapter 3, D- A. Slade, ed.  Publication
     No. TID-24190, U.S. Atomic Energy Commission  Technical Infor-
     mation Center, Oak Ridge, Tennessee, July 1968.  pp.  65-116.

                               35

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CO
en
               START
                             ATMOSPHERIC
                             CLASS ISO
                              CD
                          RADIATION INDEX = - 2
                I NO
RADIATION INDEX -
-1
1
TIME OF DAY

INSOLATION
CLASS
NOONTIME
LATE AM, EARLY PM
Ml DAM, MIDPM
EARLY AM, LATE PM
4
3
2
1
              Figure  B-2.  Flow chart of  atmospheric stability class determination.

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    TABLE  B-2.
VALUES OF a  FOR THE COMPUTATION OF o    (30)

Stability class
A
B
C
D
E
F
a
0.3658
0.2751
0.2089
0.1471
0.1046
0.0722

                       For the equation

                             ay = axb

                      where  x = downwind distance
                            b = 0.9031
         TABLE B-3.  VALUES OF THE CONSTANTS  USED TO
                     ESTIMATE VERTICAL DISPERSION  (32)

Usable range, Stability
m class 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
0.00024
0.055
0.113
1.26
6.73
18.05
C2
0.0015
0.028
0.113
0.222
0.211
0.086
0.192
0.156
0.116
0.079
0.063
0.053
2.094
1.098
0.911
0.516
0.305
0.18
d2
1.941
1.149
0.911
0.725
0.678
0.74
0.936
0.922
0.905
0.881
0.871
0.814
-9.6
2.0
0.0
-13
-34
-48.6
fa
9.27
3.3
0.0
-1.7
-1.3
-0.35
0
0
0
0
0
0

            For the equation
                            0  =
                                cxd + f
(32)  Martin, D. O., 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, Minne-
     sota,  June 23-27, 1968.   18 pp.
                                37

-------
The parameters of Equation B-10 use the same units as Equation
B-6, except Qm is the total release in grams from the source  and
DT is the total dose, grams per second per cubic meter.  Again,
the dose is the product of the concentration and sampling  time.
Equation B-10 is therefore termed a dose model.

Data Collection

Each variable for these models was determined in the field at
meteorological stations.  A stationary meteorology station was
used for high-volume sampling.  Wind speeds were averaged  every
minute with a mean recorded for each 15-min interval.  The mean
wind speed was calculated from the average of the 15-min record-
ings over the entire run.  The samplers were therefore maintained
within the plume during sampling.  The wind direction variation
was less than 0-785 rad from the centerline during the samplings.

The concentration at sampler Sg was subtracted from the concen-
trations at Si, S2, S3, and S^ 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.

For each monitor concentration reading, displayed by direct
digital readout, the mean wind speed was determined by averaging
15-s readings (a stopwatch was used) of the wind meter.  This
meter is connected to the anemometer which sits atop a 3.05-m
pole.  Distance x was approximated by pacing over the rough
terrain.

These data were recorded for each sampling run on the form shown
in Figure B-4 while in the field.  The time of day and atmos-
pheric stability (determined following 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-3.

Any factors that might have affected concentration or emission
rate were mentioned in the column labeled "Comments."  When this
form was completed,  data were programmed into a computer and
emission rate, Q, was calculated in accordance with the model
specified in the column labeled "M."
                               38

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                       \
             ANEMOMETER
               CLIPBOARD.^


                WIND METER
             WEATHER POLE
      T— ANEMOMETER
         HOUSING
     3|  CYCLONE SEPARATOR

             RESPIRABLEDUST
               MONITOR

              SAMPLING PLATFORM
            STOPWATCH

             TRIPOD STAND
           Figure  B-3.   Sampling  apparatus.

  TABLE B-3.  EXPLANATION OF FIELD  DATA FORM TERMS
     Term
               Meaning
Read.,  mg/m3

Cone.,  yg/m3



R/T


BCD,  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).
R = respirable reading;
T = total mass reading.
Background concentration.

Difference between converted concen-
  tration and background.

Calculated emission rate.
Stability for time of day  unit oper-
  ation  was sampled.
Model used referenced as 1, 2, or 3
  (point, line, or dose,
  respectively).
                           39

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              MODEL: POINT - 1
                    LINE =2
SOURCE TYPE
DATE
BY _
O
UNIT OPERATION













TIME OF DAY 	
• T* t ff A n B i t TV/
ATM. STABILITY 	
WIND
SPEED
MPH













M^^^HB**
^ imimi I ' rim
DIS1
X













FANC
Y













E, FT













TIME
MIN.













READ.
mg/m3













CONC.













. 	 — — . 	

R/T













BCD













,&3













Q,
9













TOTAL SAMPLING TIME
4 MINUTES
8 MINUTES
16 MINUTES
20 MINUTES
30 MINUTES
37 MINUTES
S1













M













COMMENTS













MULTIPLY READING BY
1
0.46
0.23
0.184
0.122
0.1
                                     Figure B-4.   Field  data form.

-------
EMISSION LEVELS

The parameters in Equation  B-6 were  measured  in  the  field  in
order to obtain the emission  rates  (Q)  per  unit  operation.  These
data were recorded on the form shown in Figure B-4 and printed
out via computer in Tables  B-4 and B-5  where  the value of  Q from
the appropriate dispersion  model  is  automatically computed.
Using the site data presented in  Section 1  of this appendix,
emission factors were computed as described below.

Blasting

From Table B-4, 36.29 g of  respirable dust were  emitted per shot
from which 2,720 metric tons  of limestone were collected and
processed.  Thus, the emission factor is
             2,720  Metric tons =  °-013 9/metric ton
Drilling
From Table B-4, the average respirable emission rate was
2.06 x 10~4 g/s per drill.  Forty hours of drilling were required
for the shot of 2,720 metric tons.  Thus, the emission factor is

           2.06 x 10"tt  (3,600) (40)   n nn   /  ^  •  ^
           - 2 yon -  -  = 0-011 g/metric ton
Front-End Loading at Quarry

From Table B-4, an average of 1.23 x 10~k g/s of total particu-
lates was emitted for the 4 min of sampling.  Thus, 0.030 g was
emitted in the filling of the 20-metric ton truck.  Thus, the
emission factor is 1.5 x 10" 3 g/metric ton.

Primary Crushing

From Table B-4, 2.966 x 10~2 g/s of total particulate and
8.776 x 10~3 g/s of respirable particles are emitted while proc-
essing 190 metric tons.  Thus, the emission factors are 562 and
166 mg/metric ton, respectively.  Primary screening is calculated
in the same manner.

Secondary Crushing

From Table B-5, 1.323 x 10~2 g/s of total particulate and an
average of 7.02 x 10~3 g/s of respirable particulate are emitted
while processing 330 metric tons.  Thus, the emission factors are
140 and 77 mg/metric tons, respectively.  Secondary screening is
calculated in the same manner.
                               41

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               TABLE  B-4.   SAMPLING DATA  AND RESULTS  (RESPIRABLE PARTICULATES)
                                     CRUSHED LIMESTONE - PLANT A
Unit operation
Blasting
Drilling
Drilling
Front- end loading"
Primary crushing
Primary crushing"
Primary screening
U
13.5
7.0
5.0
3.0
3.0
3.0
3.0
X
400.0
10.0
10.0
20.0
50.0
50.0
20.0
Y
0.0
0.0
0.0
0.0
10.0
10.0
0.0
Z
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Time
9.0
4.0
4.0
4.0
4.0
4.0
4.0
CHI
57.0
130.0
510.0
100.0
290.0
980.0
20.0

3.
1.
3.
1.
8.
2.
2.
Q
629 x
085 x
039 x
231 x
776 x
966 x
463 x

101
10-"
10-*
10-*
io-3
ID"2
ID'5
Units
g
g/s
g/S
g/s
g/s
g/s
g/s
s
D
D
D
D
D
D
D

                             TABLE B-5.   SAMPLING DATA AND  RESULTS
                                     CRUSHED LIMESTONE - PLANT B
KJ

Unit operation U
Secondary crushing 3 . 0
Secondary crushing 3.0
Secondary crushing15 3.0
Belt conveyors 3.0
Secondary screening 2.0
Secondary screening 2.0
Unpaved road 2 . 0
Unpaved road 2 . 0
Unpaved road - 2.0
X
60.
60.
60.
50.
30.
30.
70.
30.
30.

0
0
0
0
0
0
0
0
0
Y
10.
10.
10.
0.
0.
0.
0.
0.
0.

0
0
0
0
0
0
0
0
0
Z
0.
0.
0.
0.
0.
0.
0.
0.
0.
Time
0
0
0
0
0
0
0
0
0
4
4
4
4
4
4
4
8
4
.0
.0
.0
.0
.0
.0
.0
.0
.0
CHI Q
120.0 3.239 x 10~3
400.0 1.080 x 10"2
490.0 1.323 x ID'2
100.0 1.463 x 10-*
40.0 6.769 x 10"5
10.0 1.692 x 10~5
80.0 1.050 x 10"*
55.2 3.433 x 10"5
30.0 1.866 x 10"s
Units
g/s
g/s
g/s
g/m-s
g/s
g/s
g/m-s
g/m-s
g/m-s
S
D
D
D
D
D
D
D
D
D

U = wind speed, mph;







X = distance downwind, ft;
Y = distance from plume
Z = elevation of source
center
, ft
discharge,
*
1
ft

*
/





.-
Time
CHI

S
= sample time, min;


= measured concentration
less background,
= stability class.
pg/m3 ;



          Total particulate measurement.

-------
Belt Conveyors

From Table B-5, 1.463 x  KT1*  g/s  of respirable  particles  is
emitted per meter of belt.  Since the total  length of  belt was
60 m in this plant, the  emission  factor is

    1.46 x 10-^ g/m-s  (3,600  s/hr) (60 m)    n nnr   ,
         '    330 metric  tons/hr  - =  °-096  g/metric ton

Vehicular Traffic on Unpaved  Roads

From Table B-5, the three  emission  factors  in grams per meter-
second are converted to  grams per vehicle-meter (v-m)  as follows

             1.05 x 1Q-H g/m-s (240 s)    _  .n   .
             - - (3 vehicles) - ~ =  8'40 m9/v-m

            3.433 x 10~5 g/m-s (480 s)    _  ._   ,
            - (3 vehicles) - ~ =  5'49 m9/v-m

            1.866 x 10~5 g/m-s (240 s)    ,  ,_
            -            - =  4"48
for an average of  6.13 mg/v-m.   Since  each truck  (vehicle) con-
tains 20 metric  tons  and  travels an  average of 750 ma , the emis-
sion factor becomes


                                   <750 m) = 23° ^/^tric ton
    6.13 mg/v-m    20

Respirable emissions  from  unpaved  roads are about 18% of total
particulate emissions when roads are wet  (6) .  The roads were
oiled at these limestone plants; thus only about 10% of the emis
sions are estimated to be  respirable.

The emission factors  are listed in Table  B-6 along with their
fractions of respirable particulates.

COMPOSITION

The emissions! from both of the plants were analyzed for free
silica.  (For a description of the analysis methods and proce-
dures, see Reference  6.)   Table B-7 presents the free silica
analysis from crushed limestone operations.  The sample weight
was not enough to  perform  trace element analysis.  The trace
element data provided in Table B-8 are those from previous
studies.
aThe average distance  between  quarry  and  process plant  is about
 750 meters for crushed  stone  operations  (6).
                                43

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             TABLE B-6.
PARTICULATE  EMISSIONS  FROM
CRUSHED LIMESTONE PLANT
                                 Emission factor
       Operation
 Respirable
particulates,
g/metric ton
    Total
particulates,
g/metric ton
  Fraction of
  respirable
particulates, %

Drilling
Blasting
Loading at the quarry
Vehicular traffic'3
Primary crushing
Primary screening
Secondary crushing
Secondary screening
Conveying
Wind erosion of stockpiles
Unloading at stockpiles
TOTAL

0.011
0.013
0
0.23
0.17
0.0005
0.077
0.0005
0.096
_e
~e
0.6

0.11
0.075
0.0015
2.3
0.56
0.0016
0.14
0.0009
0.32
_e
~e
3.5
a
10a
17
0
10
30c
30
53 .
53c
30


17

 Estimated from drilling and blasting operations at crushed stone plants (6)
b
 On paved road between quarry and plant.

 Assumed same as primary crushing.  Conveying was from the primary crusher.

 Assumed same as secondary crushing.
a
"Negligible.
          TABLE  B-7.  FREE SILICA ANALYSIS OF EMISSIONS
                       FROM CRUSHED LIMESTONE PLANT
                      Sample   Free silica,  %

                         1              1.2
                         2
                       Estimate of  free silica
                       content.
                                 44

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     TABLE  B-8.
TRACE ELEMENT ANALYSES OF LIMESTONE
IN WEIGHT PERCENT  (1)
.
Indiana
high-
calcium
Element stone
Aluminum 0.42
Arsenic _a
Barium 0.001
Boron 0.00015
Bromine _a
Calcium
Carbon 0.49
Cesium a
Chlorine 0.0038
Chromium 0.0076
Cobalt
Copper a
Fluorine 0.0012
Gallium
Iron 0.25
Lead a
Lithium 0.00018
Magnesium >1
Manganese 0-0140
Molybdenum
Nickel
Nitrogen 0.00045
Phosphorus 0.0085
Potassium 0.058
Rubidium 0.00017
Silicon
Sodium 0.036
Strontium 0.15
Sulfur 0.022
Tin
JL JL i J.
Titanium 0.044
Vanadium 0.0015
Yttrium a
Zinc 0.0059
Note. — Blanks indicate
3 Not detected; numbers
element present.
Leigh
Valley, PA
cement
rock
0.33
0.0011
a
0.00008



a
0.00043
0.0019

a
0.00043

0.09

0.000031
0.4
0.015

0.00022
0.005
0.033
0.00007

0.17
0.22
0.003

0.016
0.00053

0.0006


Pennsylvania
cement rock
0.009

(<0.20)a
(<0.005)

39



0.001
(<0.002)
0
a
(<0.006)
0.07
(<0.01)a

0.3
0.025
(<0.002)a
a
(<0.5)

0.24 .
(<0.06)
0.039
a
(<0.008)
(<0.004)

a
(<0.06)
Illinois
Niagaran
dolomitic
stone
0.012

a
(<0.005)

35



0.00084
(<0.001)
0.00011
3
(<0.002)
o.io a
(<0 . 01)

2.9
OrfK •• <•
.011
0 ,
(<0.001)

(<0.20)a

0. 65
0.036
0.078

3
(<0.003)d



no reported data.
in parenthese

s indicate upper limit of


Trace.
                             45

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                           APPENDIX C

             SOURCE SEVERITY AND AFFECTED POPULATION


TOTAL PARTICULATES

Source Severity

Maximum source severity for particulates from ground level
sources (6) is given as


                           S = -
                                D
                                 l .814
where  S = maximum source severity
       Q = emission rate, g/s
       D = representative distance from the major source, m

The emission rate for total particulates from the representative
plant is estimated as

     Q = 450 metric tons/hr (3.50 g/metric ton) 1 hr/3,600 s
       = 0.441 g/s

Substituting the values of Q and D into Equation C-l , the sever-
ity for respirable particulates is

                    S =  (4. 020) (0.441) = 0
Affected Population

The affected population is defined as the population living
beyond the plant boundary where the source severity is  0.1 or
greater.  Since the maximum severity is less than 0.1 at the
plant boundary, the affected population is zero.

FREE SILICA

Source Severity

Source severity for free silica emissions is given as  (6)
                               46

-------
                          S  -                                 (C-2)
                               l .811*
where TLV is the  threshold limit value for respirable  dusts  con-
taining free silica  in  grams per cubic meter,  which is given as
                                 = 3'125 x 10~3
               %  free  slica + 2

The emission  rate  for respirable particulates from the represen-
tative plant  is  estimated as

     Q =  450  metric tons/hr (0.60 g/metric ton)  1 hr/3,600  s
       =  0.076 g/s

For free  silica  in respirable particulates,

               s  =  _ (316) (0.076) _ =0.14
                   (410) l -8lk (3.125 x 10~3)

Affected  Population

                     X  =  distance from source
                          I"   (316) (0.076)   I 1/1.81

                          [(S) (3.125 x 10~3) J
For  S  = 0.1,  Xs=0 ± = 0.49 km

Since  the distance of the plant boundaries is 0.26 km from the
major  source,  the affected area is
                    IT
(0.482  -  0.412)  =  0.20  km2
 For  a  representative population density of 58 persons/km2,  the
 affected population is 11 people.

 NITROGEN OXIDES AND CARBON MONOXIDE

 The  source severity for nitrogen oxides is calculated from Equa-
 tion C-3 (6):

                               = 22,200 Q                    (c_3)
                          bNOx    Di.90

 The  emission rate for nitrogen oxides from the representative
 plant  is estimated as

     Q = 450 metric tons/hr  (2.85 g/metric ton) 1 hr/3,600 s
        = 0.359 g/s

                                47

-------
Severity is thus 0.089 at 410 ra, and the affected population is
zero.

Severity for carbon monoxide is calculated from Equation C-4 (6)

                              _ 44.8 Q                       (
                          SCO ~  Di-81                       ^

The carbon monoxide severity is thus 1.7 x 10"1* at 410 m, with
zero affected population.
                               48

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                            GLOSSARY


amorphous:  Without stratification or other division;
     uncrystallized.

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 popu-
     lation is expected to lie at a specific level of confidence.

dustiness index:  Reference used in measuring the amount of
     dust settled where a material is dropped in an enclosed
     chamber.

emission burden:  Ratio of the total annual emissions of a pol-
     lutant from a specific source to the total annual state or
     national emissions of that pollutant.

fibrosis:  Growth of fibrous connective tissue in an organ in
     excess of that naturally present.

free silica:  Crystalline silica defined as silicon dioxide
     (SiO2) arranged in a fixed pattern (as opposed to an
     amorphous arrangement).

hazard factor:  Measure of the toxicity of prolonged exposure
     to a pollutant.

impact crusher:  Lightweight crusher for breaking medium-to-
     soft ores.

jaw crushers:  Crushers that give a compression or squeeze
     action between two surfaces.

limestone:  Rock consisting mainly of calcium carbonate.

noncriteria pollutant:  Pollutant for which ambient air quality
     standards have not been established.
                                 49

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precipitation-evaporation wndex:  Reference  used to compare the
     precipitation and temperature  levels  of various P-E regions
     of the United States.

processing plant:  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:  Particles  with a geometric mean
     diameter less than or equal to  7 ym.

rock:  Stone in a mass.

severity:  Hazard potential of a representative  source defined as
     the ratio of maximum time-averaged concentration to the
     hazard factor.

shorthead:  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 less,  than 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.

threshold limit value:  Concentration of an  airborne con-
     taminant to which workers may be exposed repeatedly,  day
     after day, without adverse effect.
*U.S. GOVERNMENT PRINTING OFFICE:1978 260-880/53 1-3        5 0

-------
                        /PI     TECHNICAL REPORT DATA
                        (Please read Inttmctioni on the rtvent btfore completing)
       NO.
 EPA-600/2-78-004e
4. TITLE AND SUBTITLE


 SOURCE ASSESSMENT:   CRUSHED LIMESTONE,
                       State of the Art
 . AUTHOR(S)                        '   '	'
 P. K.  Chalekode, T.  R.  Blackwood,  and
 S. R.  Archer
                                                    3. RECIPIENT'S ACCESSION NO.
                             6. REPORT DATE
                               April 1978 issuing date
                             8. PERFORMING ORGANIZATION CODE
                             8. PERFORMING ORGANIZATION REPORT NO.

                                MRC-DA-747
9. PERFORMING ORGANIZATION NAME AND ADDRESS
 Monsanto Research Corporation
 1515  Nicholas Road
 Dayton,  Ohio  45407
                             1O. PROGRAM ELEMENT NO.

                                1BB610
                             11. CONTRACT/GRANT NO.
                                                      68-02-1874
 12. SPONSORING AGENCV NAME AND ADDRESS
 Industrial Fnvironmental Research Laboratory - Cin., OH
 Office of Research and Development
 U.S.  Environmental Protection Agency
 Cincinnati, Ohio 45268
                             13. TYPE OF REPORT AND PERIOD COVERED
                               Task Final, 8/75-2/76
                             14. SPONSORING AGENCY CODE
                                EPA/600/12
 IS. SUPPLEMENTARY NOTES
 IERL-Ci project  leader for this report is John F. Martin,  513/684-4417
 16. ABSTRACT
 This  report describes a study of atmospheric emissions  from the crushed
 limestone industry.   Crushed limestone plants emit particulates from
 drilling, blasting,  transport on unpaved roads, crushing,  screening, con-
 veying,  and stockpiling.  The emission factor for total particulate from
 a representative  plant producing 450  metric tons/hr of  product is 3.5 g/
 metric ton.  Vehicular movement on  unpaved roads contributes 66% of the
 overall emissions and approximately 38% of the respirable  particulate
 emissions.  The hazardous constituent in the dust is  free  silica (1.2% by
 weight).   Nitrogen oxides and carbon  monoxide are emitted  by the blasting
 operation, but their emission factors are small in comparison to that of
 particulate emissions.  In order to evaluate the potential environmental
 effect of crushed limestone plants,  source severity was defined as the
 ratio of the maximum time-averaged  ground level concentration of an
 emission to the ambient air quality standard for criteria  pollutants or
 to  a  modified TLV for noncriteria pollutants.  The maximum source sever-
 ity for particulates is 0.032; for  free silica in the respirable particu-
 late  emissions, it is 0.12.  Emissions from this industry  in 1978 are
 estimated to be the same as they were in 1972.
17.
                            KEY WORDS AND DOCUMENT ANALYSIS
a.
                DESCRIPTORS
                                        b.lDENTIFIERS/OPEN ENDED TERMS
 Aggregates
 Air  Pollution
 Carbon Monoxide
 Mines
 Silicone dioxide
Nitrogen  Oxides
Air Pollution Contro
Stationary  Sources
Source Severity
Limestone
Particulate
Quarries
silica
                                         .  COSATI Held/Group

                                          68A
18. DISTRIBUTION STATEMENT
  Unlimited
                  19. SECURITY CLASS (This Rep
                    Unclassified
                         61
                                         2O SECURITY CLASS (TMspagel

                                           Unclassified
                                                                22. PRICE
EPA Form 222O-I (*-71)
                                     51

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