United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/3-80-019
May 1980
Air
Air Pollutant Control
Techniques for
Crushed and Broken
Stone Industry
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EPA-450/3-80-019
OAQPS Guideline Series
Air Pollutant
Control Techniques for
Crushed and Broken Stone Industry
by
Atul Kothari and Richard Gerstle
PEDCo Environmental, Inc.
11499 Chester Road
Cincinnati, Ohio 45246
Contract Nos. 68-01-4147 and 68-02-2603
EPA Project Officer: Alfred Vervaert
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
May 1980
-------
This report has been reviewed by the Emission Standards and
Engineering Division of the Office of Air Quality Planning
and Standards, EPA, and approved for publication. Mention
of trade names or commercial products is not intended to
constitute endorsement or recommendation for use. Copies
of this report are available through the Library Services
Office (MD-35), U.S. Environmental Protection Agency,
Research Triangle Park, N.C. 27711, or from National
Technical Information Services, 5285 Port Royal Road,
Springfield, Virginia 22161.
PUBLICATION NO. EPA-450/3-80-019
11
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CONTENTS
Page
1.0 INTRODUCTION 1-1
1.2 Need to Regulate 1-1
1.2 Sources and Control of Emissions 1-3
References for Chapter 1 1-6
2.0 SOURCES AND TYPES OF EMISSIONS 2-1
2.1 Stone-Processing Operations and Their
Emissions (General) 2-1
2.2 Quarrying 2-8
2.3 Crushing 2-12
2.4 Screening 2-34
2.5 Material Handling 2-40
2.6 Washing 2-46
2.7 Portable Plants 2-46
References for Chapter 2 2-50
3.0 EMISSION REDUCTION TECHNIQUES 3-1
3.1 Control of Quarrying Operations 3-1
3.2 Control of Plant Operations 3-9
3.3 Control of Fugitive Dust Source 3-25
3.4 Factors Affecting the Performance of
Control Systems 3-30
1X1
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CONTENTS (continued)
Paqe
3.5 Performance Data on Particulate Emission
Control Systems 3-34
References for Chapter 3 3-40
4.0 COSTS OF APPLYING THE TECHNOLOGY 4-1
4.1 Industry Characterization 4-1
4.2 Cost of Controlling Process Sources 4-13
4.3 Cost of Controlling Fugitive Dust Sources 4-25
References for Chapter 4 4-36
5.0 ENVIRONMENTAL IMPACT OF APPLYING CONTROL TECHNOLOGY 5-1
5.1 Impact on Air 5-1
5.2 Impact on Water Pollution 5-4
5.3 Impact on Solid Waste Disposal 5-4
5.4 Impact on Energy Consumption 5-5
5.5 Impact on Noise 5-8
References for Chapter 5 5-9
6.0 COMPLIANCE TEST METHODS AND MONITORING TECHNIQUES 6-1
6.1 Emission Measurement Methods 6-1
6.2 Monitoring Systems and Devices 6-2
References for Chapter 6 6-3
7.0 ENFORCEMENT ASPECTS 7-1
7.1 Process Considerations 7-1
References for Chapter 7 7-7
IV
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CONTENTS (continued)
Page
8.0 REGULATORY OPTIONS 8-1
8.1 Regulation Options for Process Sources 8-1
8.2 Regulation Options for Fugitive Dust Sources 8-11
8.3 Regulation Options for Drilling 8-18
8.4 Summary 8-20
APPENDIX A SOURCE TEST DATA A-l
V
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1.0 INTRODUCTION
This document presents information on the emission of par-
ticulates and their control at crushed and broken stone facili-
ties. Emissions from both process sources and fugitive dust
sources are considered. Applicable control techniques are iden-
tified and discussed in terms of performance, environmental
impacts, energy requirements, and cost. In addition, regulatory
formats for limiting particulate emissions from crushed and
broken stone facilities are identified and discussed.
1.1 NEED TO REGULATE
The term crushed and broken stone pertains to rock which has
been mined from naturally occurring mineral deposits, reduced in
size and graded to meet a variety of basic consumer needs. The
crushed stone industry is the largest non-fuel, nonmetallic
mineral industry in the United States with respect to both total
volume and value of production. Total production in 1975 was 816
Tg (901 million tons), valued at over 2.02 billion dollars. The
industry is geographically highly dispersed with all States,
except Delaware, reporting production. In general, stone pro-
duction by individual States is proportional to population and
industrial activity. The industry is also highly diverse in
1-1
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terms of unit production capacities, rock types processed, and
end product uses.
In 1975, there were approximately 5,400 active quarries in
the United States located in urban, suburban, and rural areas.
Production at these quarries ranged from less than 23,000 Mg
(25,000 tons) to several million megagrams per year. Rock mined
at these quarries is reduced to stone and graded into products by
a number of component process operations integrated into a
crushed stone plant. Plants may be either stationary or portable
and range in capacity from less than 90 Mg (100 tons) to several
thousand megagrams per hour.
Major rock types processed include limestone, which ac-
counted for 74 percent of the total production of stone in 1975;
granite (10 percent); trap rock (9 percent); and sandstone (3
percent). Important end products include construction-related
materials such as specified and unspecified construction aggre-
gates and roadstone, concrete aggregate, cement, and bituminous
aggregate. These, along with other construction-related prod-
ucts, accounted for over 80 percent of the total production of
stone in 1975. Other important end uses include agricultural
limestone, lime manufacturing, riprap and jetty stone, metallur-
gical flux, and railroad ballast.
The conversion of naturally occuring rock into crushed and
broken stone products involves a series of distinct yet interde-
pendent physical operations. These include both quarrying or
1-2
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mining operations (drilling, blasting, loading, and hauling) and
plant process operations (crushing, screening, conveying, and
other material handling and transfer operations). All are poten-
tially significant sources of particulate emissions. In a study
performed by the Argonne National Laboratory for EPA in April
1975, the crushed stone industry was ranked third highest among
2
the nation's 56 largest particulate source categories.
Estimates developed by EPA for uncontrolled plant process
operations indicate that plant process facilities alone (i.e.,
excluding quarrying and other fugitive dust sources) may emit up
to 5.5 kg of dust per megagram of crushed stone produced (11 Ibs
3
per ton), or 0.55 percent. In the absence of any air pollution
controls, industry-wide particulate emissions from process
sources alone could have exceeded 4.4 Tg (4.9 million tons) in
1975. These emissions, coupled with emissions from fugitive dust
sources and the fact that the industry is so widespread (5,400
quarries in 49 States), indicate the need for controls.
1.2 SOURCES AND CONTROL OF EMISSIONS
All quarrying and stone processing operations, including
surface mining, crushing, screening, and material handling and
transfer operations, are potential sources of particulate emis-
sions. Emission sources may be categorized as either process
sources or fugitive dust sources. Process sources include those
sources for which emissions are amenable to capture and subse-
quent control. Fugitive dust sources generally involve the
1-3
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reentrainment of settled dust by wind or machine movement.
Factors affecting emissions from either source category include
the type, quantity, and the moisture content of the rock proc-
essed; the type of equipment and operating practices employed;
and topographical and climatic factors.
Principal quarrying operations include drilling, blasting,
secondary breakage, and the loading and hauling of broken rock to
the stone processing plant. Emissions from drilling operations
are caused by the removal of cuttings and dust from the bottom of
the hole by air flushing. Generally, two control techniques are
available, (1) water injection and (2) the aspiration of dry
cuttings to a control device. Although largely uncontrollable,
emissions from blasting can be minimized by using good blasting
practices and scheduling blasts only under favorable meteorologi-
cal conditions. If secondary breakage is required, drop-ball
cranes are generally used; emissions are relatively small.
Emissions generated by the loading of broken rock into in-plant
haulage vehicles by front-end loaders or shovels can be con-
trolled by wetting down rock piles prior to loading. At most
quarries, large haulage vehicles are used to transport broken
rock from the quarry to the stone processing plant over unpaved
roads. Emissions generated are proportional to the surface
condition of the roads and the volume and speed of the vehicle
traffic. Control measures include methods to improve road sur-
faces including watering, surface treatment with chemical dust
1-4
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suppressants, soil stabilization and paving, and operational
changes to reduce traffic volume and vehicle speed.
The principal crushing plant process facilities include
crushers, screens, and material handling and transfer equipment.
Particulate emissions from process equipment are generally dis-
charged at feed and process material discharge points, and emis-
sions from material handling equipment at transfer points.
Available emission control techniques for these plant-generated
emissions include wet dust suppression, dry collection, and the
combination of the two. Wet dust suppression consists of intro-
ducing moisture into the material flow to prevent or suppress the
emission of fine particulates. Dry collection involves hooding
and enclosing dust-producing points and venting emissions to a
collection device. Combination systems utilize both methods at
different stages throughout the stone processing plant.
Other particulate emission sources include windblown dust
from open conveyors, stockpiles, and the plant yard. Control
measures range from the use of dust suppression techniques to the
erection of enclosures or windbreaks.
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REFERENCES FOR CHAPTER 1
1. Minerals Yearbook 1975 - Volume I: Metals, Minerals, and
Fuels, United States Bureau of Mines. 1977. p. 1311.
2. Priorities and Procedures for the Development of Standards
of Performance for New Stationary Sources of Atmospheric
Emissions, prepared for the United States Environmental
Protection Agency by Argonne National Laboratory, Contract
Number IAG-0463, Project Number 2. p. 39.
3. Compilation of Air Pollutant Emission Factors, Second Edi-
tion, United States Environmental Protection Agency, Publi-
cation Number AP-42. April 1973. p. 8.20-1.
1-6
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2.0 SOURCES AND TYPES OF EMISSIONS
The conversion of naturally occurring mineral deposits
into crushed-and broken-stone products involves a series of
distinct, yet interdependent, physical operations. These
include both quarrying operations such as drilling and
blasting, and plant processing operations such as crushing
and screening. All these operations are potential sources
of significant particulate emissions.
2.1 STONE-PROCESSING OPERATIONS AND THEIR EMISSIONS (GENERAL)
2.1.1 Process Description
The removal of overburden by earth-moving equipment
results in a large denuded area that is worked in benches to
form an open quarry. Rotary or percussion drills are used
to bore blastholes into the exposed stone face. After these
blastholes are charged with explosives, the rock is blasted
out of its deposit. Insufficient fragmentation may result
in the need for secondary breakage. In such cases, "drop-
ball" cranes are customarily used. The broken rock is
usually loaded into large trucks [18.2- to 68.1-Mg (20- to
75-ton capacity)] by loaders or shovelers and hauled over
unpaved roads to the primary crusher, which is often located
2-1
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in or near the quarry pit. In portable plants, usually
located in the quarry, material is fed directly to the
primary crusher. The broken rock is then transported from
the quarry to the plant area.
Plant operations common to most stone-processing instal-
lations include primary crushing, scalping, secondary crush-
ing, tertiary or finishing crushing, final screening, con-
veying, storage and shipping, and in some instances, washing.
Depending on the purpose of the plant and the rock type
processed, all or only a few of these operations are per-
formed.
As illustrated in Figure 2-1, broken rock obtained from
the quarry is dumped into a hoppered feeder, usually a
vibrating grizzly type, and fed to the primary crusher for
initial reduction. Jaw or gyratory crushers are often used,
but impact crushers are gaining favor when low-abrasion rock
types (like limestones) are crushed and when high reduction
ratios are desired. The crusher product [approximately 76.2
to 305 mm (3 to 12 in.) in size] and the grizzly throughs
are discharged onto a belt conveyor and transported to a
surge pile or silo for temporary storage.
The material is then reclaimed by a series of vibrating
feeders under the surge pile and conveyed to a scalping
screen that separates the process flow into three fractions
2-2
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VSURGE PILE
ro
FINISHING
SCREENS
Figure 2-1. Flowsheet of typical crushed-stone plant.
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(oversize, undersize, and throughs) prior to secondary
crushing. The oversize is discharged to the secondary
crusher for further reduction. The undersize, which re-
quires no further reduction at this stage, bypasses the
secondary crushers, thus reducing its crushing load. The
throughs, which contain unwanted fines and screenings, are
removed from the process flow and stockpiled as crusher-run
material. Secondary crushers are usually gyratory or cone
type, but impact crushers are used at some installations.
The product from the secondary crushing stage, approxi-
mately 25.4 mm (1 in.) or less in size, is transported to a
secondary screen for further sizing. Sized material from
this screen is conveyed or discharged directly to tertiary
cone crushers or hammermills. The product from the tertiary
crushers is shuttled back to the secondary screen, forming a
closed circuit with a fixed-top size. The throughs from
this screen are then discharged to a conveyor and elevated
to a screen house or tower containing multiple screen lines
for final sizing. At this point, end products of desired
gradation are discharged directly to finished-product bins
or are stockpiled in open areas by conveyors or trucks.
Stone washing is sometimes required to meet particular
end-product specifications or demands, such as for concrete
aggregate. In washing plants, the material falls onto fine
2-4
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mesh screens, where it is sprayed heavily with water.
Unwanted fines are usually discharged to a settling pond.
2.1.2 Sources of Emissions
Unlike emissions from sources such as boilers and
incinerators, emissions from sources in this industry have
not traditionally been confined and discharged through
stacks or similar outlets. Although difficult to do so,
emissions from drilling, crushing, screening, and conveyor
transfer points can be captured with a hood and vented to a
control device. On the other hand, emissions from sources
such as blasting, stockpiles, and haul roads cannot be
captured by a hood or similar device. Emissions from these
sources can, however, often be reduced by wetting the sur-
face, paving haul roads, or implementing a similar measure.
Although huge storage silos or enclosures can be constructed
to store materials, such a measure is not considered econom-
ically feasible for this industry. In assessing a situation
like this or when reliable data are not available, engineer-
ing judgment has been relied upon to prepare this document.
In this document, sources that are amenable to control
by the capture of emissions with a hood or similar device
are termed "process" sources while those that are not amen-
able to this treatment are termed "fugitive dust" sources.
2-5
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Sources included within each category are listed in Table
2-1. The term stone-processing operations refers to both
quarrying and plant operations.
Table 2-1. STONE-PROCESSING EMISSION SOURCES
process sources
Drilling
Crushing
Screening
Conveyor transfer points
Fugitive dust sources
Blasting
Loading and hauling
Haul roads
Stockpiles
Conveying
3 Emissions and Factors that Influence Emissions
All stone-processing operations are potential sources
of particulate emissions. Factors affecting emissions that
are common to most stone-processing operations include
moisture content of the rock, type of rock processed, type
of equipment, and operating practices employed. These
factors apply to both fugitive dust and process sources in
quarry and plant operations.
Depending on geographic and climatic conditions, the
inherent moisture content or wetness of quarried rock may
range from nearly zero to several percent. The effect of
moisture content is especially important during quarrying,
material handling, and initial plant process operations such
2-6
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as primary crushing. Surface wetness causes fine particles
to agglomerate or adhere to the faces of larger stones,
resulting in a dust suppression effect. However, as new
fine particles are created by crushing and attrition and
moisture content is reduced by evaporation, this suppressive
effect diminishes and may even become insignificant.
The type of rock processed is also important. Soft
rocks produce a higher percentage of screenings [minus 6.4-
mm (1/4-in.) to 200-mesh] than do hard rocks because they
are more friable. Therefore, processing of soft rocks has
the greater potential for emissions. Major rock types
arranged in order of increasing hardness are limestone and
dolomite, sandstone, granite, trap rock, quartzite, and
quartz. Limestones could therefore be expected to produce
the highest uncontrolled emissions, quartzitic materials the
least.
The type of equipment and operating practices employed
also affect uncontrolled emissions. Equipment selection is
based on a variety of parameters, including quarry charac-
teristics, rock type processed, and desired end products.
Emissions from process equipment such as crushers, screens,
and conveyors are generally a function of the size distri-
bution of the material, and the amount of mechanically
induced velocity imparted to it. The effect of equipment
2-7
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type on uncontrolled emissions from all sources is more
fully discussed in subsequent sections of this report.
Information is limited on the amount of emissions from
crushed-stone operations. Table 2-2 presents emission
factors for uncontrolled emissions listed in Compilation of
2
Air Pollutant Emission Factors, AP-42. Based on these
estimates, process sources alone, excluding drilling, emit
about 5.5 kg of dust per megagram of crushed stone produced
(11 Ib/ton).
2.2 QUARRYING
Principal quarrying operations include drilling, blast-
ing, secondary breakage, loading, and hauling the broken
rock to the plant site. All these operations can cause
visible particulate emissions.
Drilling is the boring of holes into bedded rock.
These blastholes are charged with explosives and the rock is
blasted out of its deposit. Tractor- or truck-mounted
pneumatic rotary or percussion drills are commonly used to
cut blastholes. Rotary drills cut the blasthole by the
abrasive action of a revolving drill bit, usually a roller
cone type, which is attached to the end of a drill -rod.
Percussion drills use compressed air to drive a piston that
transmits a series of impacts or hammerblows either through
the drill rod or directly to the bit. This type of drill
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Table 2-2. PARTICULATE EMISSION FACTORS FOR
STONE-PROCESSING OPERATIONS2
Process operation
Primary crushing
Secondary crushing and screening
Tertiary crushing and screening
Recrushing and screening
Screening, conveying, and handling
Uncontrolled
emission factor3
kg/Mg
0.25
0.75
3.0
2.5b
1.0
5.5
( Ib/ton)
(0.5)
(1.5)
(6.0)
(5.0b)
(2.0)
(11.0)
Based on primary crusher throughput.
Based on recrushing and screening throughput.
Assuming 20 percent of the primary crusher through-
put undergoes recrushing, the emission factor may
be expressed as 0.5 kg/Mg of primary crusher
throughput (l Ib/ton).
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forms the blasthole by the chipping and pulverizing action
of the bit impacting against the rock surface. Rotary
drills are normally used in softer rock formations like
limestones, and percussion drills are used for harder rocks.
The number, depth, spacing, and diameter of blastholes
depend on the characteristics of the explosive used, the
type of burden or rock to be fragmented, and characteristics
of the rock formation, such as the location of dips, joints,
and seams.
Emissions from drilling operations are caused primarily
by the removal of cuttings and dust from the bottom of the
hole. Compressed air released down the hollow drill center
forces cuttings and dust up and out the annular space formed
between the hole wall and drill. The type of rock drilled,
its moisture content, the type of drill used, the hole
diameter, and penetration rate all affect the amount of
uncontrolled emissions. An estimate for granite is 0.4 g/Mg
(0.0008 Ib/ton) stone.3
Blasting is used to displace solid rock from its quarry
deposit and fragment it into sizes that will require a
minimum of secondary breakage and can be readily handled by
loading and hauling equipment. Blastholes are loaded with a
predetermined amount of explosives, which are then stemmed
and detonated. Explosives most commonly used in the indus-
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try are dynamites and blasting agents. Dynamites are highly
explosive and come in a variety of types and grades, many of
which contain nitroglycerine. Blasting agents are insensi-
tive chemical mixtures of fuels and oxidizers. Mixtures of
ammonium nitrate and fuel oil (ANFO) are the most common
types of blasting agents and consist of coated or uncoated
fertilizer-grade ammonium nitrate pellets, prills, or
granules mixed with 4 to 6 percent fuel oil.
Blasting frequency ranges from several shots per day to
one per week, depending on the plant capacity and the size
of individual shots. The effectiveness of a shot depends on
the characteristics of the explosive and the rock. Emis-
sions from blasting are obvious as detected by visual obser-
vation and inherently unavoidable. Factors affecting emis-
sions include the size of the shot, blasting practices
employed, rock type, and wetness. An estimate for granite is
80 g/Mg (0.16 Ib/ton) of stone.3
Secondary breakage, if required, is usually done by
drop-ball cranes. Normally, a pear-shaped or spherical
drop-ball, weighing several tons, is suspended by a crane
and dropped on the oversize rock as many times as needed to
break it. Emissions are relatively insignificant as judged
by visual observations.
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Broken rock is normally excavated and loaded onto
trucks by shovelers and front-end loaders. The broken rock
is either dumped directly into the primary crusher (when
portable plants are used) or into large 18.2- to 68-Mg (20-
to 75-ton) trucks for transport to the primary crusher,
located at the plant or near the quarry site.
At most quarries, the broken rock is transported from
the quarry to the primary crusher over unpaved haul roads.
Traffic on these roads is responsible for a large portion of
the fugitive dust generated by quarrying operations. The
amount of fugitive dust ranges from 1.68 to 4.45 kg (3.7 to
9.8 Ib) per vehicle mile on a "dry" day. Assuming 166 dry
days, this translates to yearly range of 0.48 to 1.23 kg
(1.7 to 4.5 Ib) per vehicle km (mile) per year. Factors
affecting fugitive dust emissions from hauling operations
include the composition of the road surface, the wetness of
the road, and the volume and speed of the vehicle traffic.
2.3 CRUSHING
Crushing or comminution is the process by which coarse
material is reduced to a desired size for mechanical separa-
tion (screening) by application of mechanical energy and by
attrition. During crushing, sufficient mechanical stress is
applied to a rock particle to fracture it. The mechanical
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stress is applied by either compression or impact. With
impact stress, the breaking force is applied almost instan-
taneously, whereas with compression, the rock particle is
squeezed relatively slowly until it fractures. All crushers
use both compression and impaction. Table 2-3 ranks crush-
ers according to the predominant crushing mechanism used
(from top to bottom, compression to impaction). In all
cases, some reduction is accomplished by attrition, the
rubbing of stone on stone or on metal surfaces.
The size of the product from compression-type crushers
is controlled by the crusher setting at the bottom of the
crushing chamber (the space between the crushing surfaces
compressing the stone particle). This produces a relatively
closely graded product with a small proportion of fines. In
contrast, crushers that reduce by impact produce a wide
range of sizes and a high proportion of fines.
Because the size reduction achievable by one machine is
limited, two or more reduction stages are required. As
noted previously, the various stages include primary, secon-
dary, and tertiary crushing. Basically, four types of
crushers are used in the industry: jaw, gyratory, roll, and
impact crushers.
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Table 2-3. MAJOR CRUSHING MECHANISM
UTILIZED BY VARIOUS CRUSHERS
Compression
Impaction
Double-roll crusher
Jaw crusher
Gyratory crusher
Single-roll crusher
Rod mill (low speed)
Ball mill
Rod mill (high-speed)
Hammermill (low-speed)
Impact breaker
Hammermill (high-speed)
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2.3.1 Types of Crushing Equipment
Jaw Crushers —
Jaw crushers consist of a vertical fixed jaw and a
moving inclined jaw that is operated by single or paired
toggles. Rock is crushed by compression as a result of the
opening and closing action of the movable jaw against the
fixed jaw. Jaw crushers are principally used in the indus-
try for primary crushing.
The most commonly used jaw crusher is the Blake or
double-toggle type. As illustrated in Figure 2-2, an
eccentric shaft drives a Pitman arm that raises and lowers a
pair of toggle plates to open and close the moving jaw which
is suspended from a fixed shaft. In a single-toggle jaw
crusher, the moving jaw itself is suspended from an eccen-
tric shaft. The lower part of the jaw is supported by a
rolling toggle plate (Figure 2-3). Rotation of the eccen-
tric shaft produces a circular motion at the upper end of
the jaw and an elliptical motion at the lower end.
The size of a jaw crusher is defined by its feed open-
ing dimensions, which may range from about 152 by 304 mm (6
by 12 in.) to 2.13 by 1.68 mm (84 by 66 in.). The size
reduction obtainable may range from 3:1 to 10:1, depending
on the nature of the rock. Crusher capacities are variable
and depend on the unit and its discharge setting. Table 2-4
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FEED
SWING JAW
CRUSHER PLANT
TOGGLES
OUTLET
Figure 2-2. Double-toggle jaw crusher
(Courtesy of Pit and Quarry Handbook).
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FEED
CRUSHER PLATE
SWING JAW
OUTLET
TOGGLE
Figure 2-3. Single-toggle jaw crusher
(Courtesy of Pit and Quarry Handbook).
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Table 2-4. APPROXIMATE CAPACITIES OF JAW CRUSHERS
(Discharge opening - closed)
to
i
M
00
Size
mm (in. )
0.914 x 0.610
(36 x 24)
1.07 x 1.52
(42 x 60)
1.22 x 1.07
(48 x 42)
1.52 x 1.22
(60 x 48)
2.13 x 1.68
(84 x 66)
Smallest
discharge
opening,
mm (in. )
76 (3)
101 (4)
127 (5)
127 (5)
203 (8)
Capacity3
Mg/h (tons/h)
68.0 (75)
118.1 (130)
158.8 (175)
217.8 (240)
362.9 (400)
Largest
discharge
opening,
mm (in. )
152 (6)
203 (8)
203 (8)
229 (9)
305 (12)
Capacity
Mg/h (tons/h)
145.1 (160)
181.4 (200)
249.5 (275)
408.2 (450)
544.3 (600)
Based on rock weighing 1
604 Mg/m3 (100 lb/ft3).
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presents approximate capacities for a number of jaw-crusher
sizes at both minimum and maximum discharge settings.
Gyratory Crushers —
A gyratory crusher is a jaw crusher with circular jaws
that crush the material between it. As indicated in Table
2-5, a gyratory crusher has a much greater capacity than a
jaw crusher with an equivalent feed opening.
The three basic types of gyratory crushers are pivoted-
spindle, fixed-spindle, and cone. The fixed- and pivoted-
spindle gyratory crushers are used for primary and secondary
crushing, and cone gyratory crushers for secondary and
tertiary crushing. The large gyratory crushers are sized
according to feed opening, and the small units according to
cone diameter.
The pivoted-spindle gyratory crusher (Figure 2-4) is
a crushing head mounted on a shaft that is suspended from
above and is free to pivot. The bottom of the shaft is
seated in an eccentric sleeve that revolves, thus causing
the crusher head to gyrate in a circular path within a
stationary concave circular chamber. The crushing action is
similar to that of a jaw crusher in that the crusher element
reciprocates to and from a fixed crushing plate. Because
part of the crusher head is working at all times, the dis-
charge from the gyratory crusher is continuous rather than
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Table 2-5. APPROXIMATE CAPACITIES OF GYRATORY CRUSHERS
NJ
I
K),
O
Size
mm (in. )
0.762 (30)
0.914 (36)
1.067 (42)
1.219 (48)
1.372 (54)
1.524 (60)
1.829 (72)
Smallest
discharge
opening,
mm (in. )
101 (4)
114 (4-1/2)
101 (4)
140 (5-1/2)
159 (6-1/4)
178 (7)
229 (9)
Capacity
Mg/h (tons/h)
181.4 (200)
335.5 (370)
380.9 (420)
680.4 (750)
816.5 (900)
1088.0 (1200)
1814.0 (2000)
Largest
discharge
opening,
mm (in. )
165 (6-1/2)
178 (7)
191 (7-1/2)
229 (9)
241 (9-1/2)
254 (10)
305 (12)
Capacity
Mg/h (tons/h)
408.2 (450)
544.3 (600)
635.0 (700)
1088.0 (1200)
1451.5 (1600)
1814.0 (2000)
2721.6 (3000)
Based on rock weighing 1.604 Mg/m (100 Ib/ft ).
-------
FEED
CRUSHING
SURFACES
DRIVE
ECCENTRIC
OUTLET
Figure 2-4. Gyratory crusher
(Courtesy of Pit and Quarry Handbook).
2-21
-------
intermittent as in a jaw crusher. The crusher setting is
determined by the wide-side opening at the discharge end and
is adjusted by raising or lowering the crusher head.
Unlike the pivoted-spindle gyratory crusher, the fixed-
spindle gyratory crusher has a crushing head mounted on an
eccentric sleeve fitted over a fixed shaft. This produces a
uniform crushing stroke from the top to the bottom of the
crushing chamber.
For fine crushing, the gyratory crusher is equipped
with flat heads and converted to a cone crusher (Figure 2-
5). Usually, the lower section has a parallel zone. This
results in a large discharge-to-feed area ratio that makes
it especially suitable for fine crushing at high capacity.
Also, unlike regular gyratory crushers, the cone crusher
sizes at the closed-side setting and not the open-side
setting. This assures that the material discharge is
crushed at least once at the closed-side setting. Cone
crushers yield a cubical product and a high percentage of
fines because of interparticle crushing (attrition). They
are the most commonly used crusher in the industry for
secondary and tertiary reduction. Table 2-6 presents per-
formance data for typical cone crushers.
2-22
-------
FEED
CRUSHING
SURFACES
ECCENTRIC
Figure 2-5. Cone crusher
(Courtesy of Pit and Quarry Handbook).
2-23
-------
Table 2-6. CAPACITIES OF CONE CRUSHERS'
[Mg/h (tons/h) except as noted]
Size of
crusher,
m (ft)
0.61 (2)
0.91 (3)
1.22 (4)
1.68 (5-1/2)
2.13 (7)
Discharge setting
9. 5 mm
(3/8 in.)
18.0 (20)
31.7 (35)
54.0 (60)
12.7 mm
(1/2 in.)
22.7 (25)
36.0 (40)
72.0 (80)
19.1 mm
(3/4 in.)
31.7 (35)
64.8 (70)
108.0 (120)
180.0 (200)
299.0 (300)
25 . 4 mm
(1 in.)
137.0 (150)
248.0 (275)
407.0 (450)
28 .1 mm
(1-1/2 in.)
310.0 (340)
544.0 (600)
to
I
to
-------
Roll Crushers —
Single-roll and double-roll crushers are used primarily
at intermediate or final reduction stages and often at por-
table plants. As illustrated in Figure 2-6, the double-roll
crusher consists of two heavy parallel rolls that turn
toward each other at identical speeds ranging from 50 to 300
revolutions per minute. Usually, one roll is fixed and the
other set by springs. Roll diameters normally range from
0.6 to 2.0 m (24 to 78 in.) with narrow face widths about
half the roll diameter. Rock particles are caught between
the rolls and crushed almost totally by compression at a
reduction ratio of 3 or 4 to 1. These units, which produce
few fines and no oversize, are especially effective for re-
ducing hard stone to a final product ranging from 6.4 m (1/4
in.) to 20-mesh.
The working elements of a single-roll crusher include a
toothed or knobbed roll and a curved crushing plate, which
may be corrugated or smooth. The crushing plate is gener-
ally hinged at the top, and its setting is held by a spring
at the bottom, as shown in Figure 2-7. The feed, caught
between the roll and crushing plate, is broken by a combina-
tion of compression, impact, and shear. These units accept
feed sizes up to 0.51 m (20 in.) and have capacities up to
454 Mg/h (500 tons/h). In contrast with the double-roll,
2-25
-------
MOVABLE ROLL v FEED
STATIONARY ROLL
OUTLET
Figure 2-6. Double-roll crusher
(Courtesy of Pit and Quarry Handbook)
2-26
-------
FEED
OUTLET
TEETH
BREAKER PLATE
-ROLL
Figure 2-7- Single-roll crusher
(Courtesy of Pit and Quarry Handbook).
2-27
-------
the single-roll crusher is used principally for reducing
soft materials such as limestones.
Impact Crushers --
Impact crushers, including hammermills and impactors,
use the force of fast-rotating, massive impellers or hammers
to shatter free-falling rock particles. These units have
very high reduction ratios and produce a cubical product
spread over a wide range of particle sizes with a large pro-
portion of fines. This makes their application in industries
such as cement manufacturing and agstone production extreme-
ly cost effective by reducing the need for subsequent grind-
ing machines.
A hammermill consists of a high-speed horizontal rotor
having several rotor discs to which sets of hammers are
attached (Figure 2-8). As rock particles are fed into the
crushing chamber, they are shattered by the hammers, which
attain peripheral speeds as high as 76.2 m/s (250 ft/s).
The shattered rock then collides with a steel breaker plate
and is fragmented even further. A cylindrical grating or
screen positioned at the discharge opening restrains over-
size material until it is reduced to a size small enough to
pass between the grate bars. Rotor speeds range from 250 to
1800 revolutions per minute, and capacities to over 907 Mg/h
(1000 tons/h). Product size is controlled by rotor speed,
spacing between the grate bars, and hammer length.
2-28
-------
BREAKER PLATE
FEED
OUTLET
SWING HAMMERS
ROTOR
GRATE BARS
Figure 2-8. Hammermill crusher
(Courtesy of Pit and Quarry Handbook)
2-29
-------
An impact breaker (Figure 2-9) is similar to a hammer-
mill except that it has no grate or screen to act as a res-
training member. Feed is broken by impact alone. Adjustable
breaker bars are used instead of plates to reflect material
back into the path of the impellers. Primary-reduction
units are available that can reduce quarry-run material to
about 25.4 mm (1 in.) at a capacity of more than 907 Mg/h
(1000 tons/h). Although these units are not appropriate for
hard, abrasive materials, they are ideal for soft rock such
as limestone.
2.3.2 Sources of Emissions
The generation of particulate emissions is inherent in
the crushing process. Emissions are most apparent at crush-
er feed and discharge points. Emissions may be influenced
by a variety of factors, including moisture content of the
rock, type of rock processed, and type of crusher used. All
but the last have been previously discussed.
Whether the crushing equipment is compression or impact
type has the greatest influence on emissions. The mechanism
affects particle size distribution of the product, especial-
ly the proportion of fines produced, and the amount of
mechanically induced energy that is imparted to these fines.
Impact crushers produce a larger proportion of fines
than do compression crushers. This is illustrated in
2-30
-------
FEED
j
\
IMPELLER
BREAKER BARS
IMPELLER BARS
Figure 2-9. Impact crusher
(Courtesy of Pit and Quarry Handbook).
2-31
-------
Figure 2-10, which compares the particle size distributions
produced by the reduction of limestone with a hammermill and
a jaw crusher. The distribution curve for the hammermill is
characteristic of impact crushers in general and demonstrates
the high proportion of fines contained in the crusher pro-
duct. The distribution curve for the jaw crusher illustrates
the particle size distribution produced by compression-type
crushers including jaw, gyratory, cone, and roll crushers.
These crushers are designed to reduce material to a size
regulated by the crusher setting, the gap between the
crushing faces at the point of discharge. The slope of the
curve demonstrates how a compression crusher produces a
large proportion of particles corresponding to the crusher
setting.
In addition to generating more fines, impact crushers
also impart more velocity to them as a result of the fan-
like action produced by the whirling hammers. For these two
reasons, impact crushers generate more uncontrolled parti-
culate emissions per Mg (ton) of stone processed than any
other crusher type.
The uncontrolled emissions from jaw, gyratory, cone,
and roll crushers closely parallel the reduction stage to
which they are applied. As indicated in Table 2-2, the
greater the reduction, the higher the emissions. In all
2-32
-------
100
o
t—i
o
S 80
UJ
to
to
LU
_J
O
QL.
U_
O
O
o:
60
40
I
20 40 60 80
PARTICLE SIZE EXPRESSED AS A PERCENT OF MAXIMUM
PARTICLE SIZE PASSING THRU THE CRUSHER
TOO
EXAMPLE 1 - HAMMERMILL PRODUCT HAVING A MAXIMUM
SIZE OF 38.1 mmTl.STN.), APPROXI-
MATELY 85% (BY WEIGHT) OF THE PRODUCT
WOULD BE LESS THAN 22.9 mm (0.9 IN).
(60% X 1.5).
EXAMPLE 2 - JAW-CRUSHER PRODUCT HAVING A MAXIMUM
SIZE OF 101.6 mm (4 IN.), APPROXI-
MATELY 62% (BY WEIGHT) OF THE PRODUCT
WOULD BE LESS THAN 61.0 (2.4 IN.) (60% X4)
Figure 2-10.
Characteristic Particle Size Distribution
for Different Crushing Mechanisms.6
2-33
-------
likelihood, primary jaw crushers produce more dust than com-
parable gyratory crushers because of the bellows effect of
jaw and because gyratory crushers are usually choke-fed,
thus minimizing the open spaces from which dust may be
emitted. For subsequent reduction stages, cone crushers
produce more fines as a result of attrition and consequently
generate more dust.
2.4 SCREENING
Screening is the process by which a mixture of stones
is classified and separated according to size. The material
to be screened is dropped onto a screening surface with
openings of a desired size. It is then separated into two
fractions, undersizes which pass through the screen open-
ings, and oversizes which are retained on the screen surface.
Multiple screens are used to divide the material into
several fractions of known particle size distribution.
Screening surfaces may be constructed of metal bars, per-
forated or slotted metal plates, or woven wire cloth. Woven
screens may range in mesh size from 101.6 mm (4 in.) to
400-mesh [0.841 mm (0.0331 in.)].
The efficiency of a screening operation is a measure of
its success in separating two or more material fractions.
Screening efficiency in the crushed-stone industry ranges
2-34
-------
from 60 to 75 percent. The capacity of a screen, determined
primarily by the open area of the screening surface and the
physical characteristics of the feed, is usually expressed
2 2
in Mg/h per m (tons/h per ft ). Although screening may be
performed wet or dry, dry screening is the more common.
Screening equipment commonly used in the crushed-stone
industry includes grizzlies, shaking screens, vibrating
screens, and revolving screens.
2.4.1 Types of Screening Equipment
Grizzlies —
Grizzlies consist of a set of uniformly spaced horizon-
tal or inclined bars, rods, or rails. The bars are usually
wider on the top surface than they are on the underside to
prevent stone particles from becoming wedged between them.
The spacing between the bars ranges from 60.8 to 203.2
mm (2 to 8 in.). Bars are usually constructed of manganese
steel or other highly abrasion-resistant material.
Grizzlies are used mainly to remove fines prior to
primary crushing, thus reducing the load on the primary
crusher. Grizzlies may be stationary, cantilevered (fixed
at one end with the discharge end free to vibrate), or
mechanically vibrated. Vibrating grizzlies are simple bar
grizzlies mounted on eccentrics (Figure 2-11). The entire
assembly oscillates at about 100 strokes a minute to promote
better flow through and across the grizzly surface.
2-35
-------
Figure 2-11. Vibrating grizzly
(Courtesy of Pit and Quarry Handbook) .
2-36
-------
Shaking screens —
The shaking screen consists of a retangular frame with
perforated plate or wire cloth screening surfaces. These
screens, usually suspended by rods or cables and inclined at
an angle of 14 degrees, are mechanically shaken parallel to
the plane of material flow at speeds ranging from 60 to 800
strokes per minute and at amplitudes ranging from 19.5 to
228.6 mm (3/4 to 9 in.). They are used for screening
coarse material 12.7 mm (1/2 in.) or larger.
Vibrating screen —
The vibrating screen has replaced most other screen
types when a large capacity and high efficiency are desired.
It is by far the most commonly used screen type in the
crushed-stone industry. A vibrating screen (Figure 2-12)
essentially consists of an inclined flat or slightly convex
screening surface that is rapidly vibrated in a plane normal
or nearly normal to the screen surface. The screening
motion is of small amplitude but high frequency, normally in
excess of 3000 cycles per minute. The vibrations may be
generated either mechanically by means of an eccentric
shaft, unbalanced fly wheel, cam, and tappet assembly, or
electrically by means of an electromagnet.
Mechanically vibrated units are operated at about 1200
to 1800 rpm and at amplitudes of about 3.1 to 12.7 mm (1/8
2-37
-------
Figure 2-12. Vibrating screen
(Courtesy of Pit and Quarry Handbook).
2-38
-------
to 1/2 in.). Electrically vibrated screens are available in
standard sizes from 0.3 to 1.8 m (12 in. to 6 ft) wide and
0.8 to 6.1 m (2-1/2 to 20 ft) long. A complete screening
unit may have one, two, or three decks.
Revolving screens —
This screen type consists of an inclined cylindrical
frame around which is wrapped a screening surface of wire
cloth or perforated plates. Feed material is delivered at
the upper end and, as the screen is rotated, undersized
material passes through the screen openings while the over-
sized is discharged at the lower end. Revolving screens are
available up to 1.2 m (4 ft) in diameter and usually run at
4
15 to 20 revolutions per minute.
2.4.2 Source of Emissions
Dust is emitted from screening operations as a result
of the agitation of dry stone. The level of uncontrolled
emissions depends on the particle size of the material
screened, the amount of mechanically induced energy trans-
mitted, and other factors previously discussed.
Generally, the screening of fines [less than 3.2 mm
(1/8 in.)] produces higher emissions than the screening of
coarse sizes. Also, screens agitated at large amplitudes
and high frequency emit more dust than those operated at
small amplitudes and low frequencies.
2-39
-------
2.5 MATERIAL HANDLING
Throughout a crushed-stone plant handling devices are
used to transport materials from one point to another. The
most common devices include feeders, belt conveyors, bucket
elevators, and screw conveyors. Pneumatic systems are
rarely used in this industry.
2.5.1 Types of Handling Equipment
Feeders —
Feeders are relatively short, heavy-duty conveying
devices that receive material from and deliver it to process
units, especially crushers, at a uniform rate. The various
types of feeders used are the apron, belt, reciprocating-
plate, vibrating, and wobbler.
Apron feeders are composed of overlapping metal pans or
aprons hinged together or linked by chains to form an end-
less conveyor that is supported by rollers spaced between a
head and tail assembly. These units are constructed to
withstand high impact and abrasion and are available in
various widths [0.46 to 1.8 mm (18 to 72 in.)] and lengths.
Belt feeders are essentially short, heavy-duty conveyor
belts equipped with closely spaced support rollers. Adjust-
able gates are used to regulate feed rates. This type of
feeder is available in 0.48- to 1.2-m (18- to 48-in.)
widths and 0.91- to 3.7-m (3- to 12-ft) lengths, and is
operated at speeds of 0.2 to 0.51 m/s (40 to 100 ft/min).
2-40
-------
A reciprocating-plate feeder is a heavy-duty horizontal
plate driven in an oscillating motion that causes the mater-
ial to move forward at a uniform rate. The feed rate is
controlled by adjusting the frequency and length of the
stroke.
Vibrating feeders operate at a relatively high fre-
quency and low amplitude. Their feed rate is controlled by
the slope of the feeder bed and the amplitude of the vibra-
tions. These feeders are available in a variety of sizes,
capacities, and drives. When combined with a grizzly, they
perform both scalping and feeding functions.
Wobbler feeders also perform the dual task of scalping
and feeding. These units consist of a series of closely
spaced elliptical bars that are mechanically rotated, caus-
ing oversize material to tumble forward to the discharge end
and undersize material to pass through the spaces. The feed
rate is controlled by the bar spacing and the speed of
rotation.
Belt conveyors --
Belt conveyors are the most widely used means of trans-
porting, elevating, and handling materials in the crushed-
stone industry. As illustrated in Figure 2-13, a belt
conveyor is an endless belt supported on a series of idlers
that are usually arranged so that the belt forms a trough.
2-41
-------
BELT
IDLERS
Figure 2-13. Belt conveyor
(Courtesy of Pit and Quarry Handbook).
2-42
-------
The belt, commonly constructed of reinforced rubber, is
stretched between a drive or head pulley and a tail pulley.
Although belt widths may range from 0.36 to 1.6 m (14 to 60
in.)/ widths of 0.76 to 0.91 m (30 to 36 in.) are the most
common. Normal operating speeds may range from 1.0 to 20
m/s (200 to 400 ft/min). Depending on the rock density,
belt width, and belt speed, load capacities may be in excess
of 136 Mg/h (1500 tons/h).
Elevators --
Bucket elevators are utilized when substantial eleva-
tion is required within a limited space. The buckets are
attached to a single- or double-strand chain or belt that is
supported and driven by a head and foot assembly. Figure
2-14 depicts the three most common types of bucket elevators,
high-speed centrifugal-discharge, slow-speed positive- or
perfect-discharge, and continuous-discharge.
In the centrifugal-discharge elevator, the buckets are
evenly spaced on a single-strand chain or belt. As the
buckets round the tail pulley, which is housed within a
suitable curved boot, they scoop up their load and elevate
it to the point of discharge. The buckets are spaced so
that at discharge the material is thrown out by the centri-
fugal action of the bucket rounding the head pulley.
2-43
-------
O X,
CENTRIFUGAL DISCHARGE
/
«
>j
19
-------
The positive-discharge elevator also has spaced buck-
ets, but it has a double-strand chain and a different dis-
charge mechanism. An additional sprocket set below the head
pulley effectively bends the strands back under the pulley,
causing the bucket to be totally inverted and resulting in a
positive discharge.
The continuous-discharge elevator utilizes closely
spaced buckets attached to a single- or double-strand belt
or chain. Material is loaded directly into the buckets
during ascent and is discharged gently. The back of the
preceding bucket is used as a discharge chute.
Screw conveyors —
Screw conveyors are comprised of a steel shaft with a
spiral or helical fin that when rotated pushes material
along a trough. Because these conveyors are normally used
with wet material, they create no significant emission
problem.
2.5.2 Source of Emissions
Particulates may be emitted from any of the material
handling (conveying) operations. Most of the emissions from
material handling occur at transfer points, since transport
of material on the conveyor causes little disturbance of
air, and emissions that occur due to the wind are judged to
be minimal. The transfer points include transfers from a
2-45
-------
conveyor onto another, into a hopper, and onto a storage
pile. The amount of uncontrolled emissions depends on the
size distribution of the material handled, the belt speed,
and the free-fall distance. Reference 3 estimates an emis-
sion rate of 750 g/Mg (1.5 Ib/ton) from transfer and convey-
ing operations in a crushed-granite plant.
2.6 WASHING
To meet specifications some aggregate products such as
concrete aggregate require washing to remove fines. Al-
though a variety of equipment is available, washing screens
are generally used. A washing screen is a standard, in-
clined, vibrating screen with high-pressure water-spray bars
installed over the screening surface. Stone passing over
the screen is washed and classified. Because it is a wet
process, it essentially produces no particulate emissions.
2.7 PORTABLE PLANTS7
A portable plant may consist of a single chassis on
which one or several processing units may be mounted, or it
may consist of a combination of chassis on which various
types of units are mounted to provide a sequence of opera-
tions such as feeding, crushing, screening, sizing, washing,
and stacking or loading. The processing steps for crushed
stone are the same in both stationary and portable plants.
2-46
-------
In a portable plant, however, the processing units are
squeezed into a very restricted space. Thus, the entire
plant can be readily moved from one quarry site to another.
Portable plants come in various designs and are adapt-
able to practically any process conditions and product
specifications. They may be grouped into three categories:
simple, duplex, and combination. In the simple portable
plant a single screen receives material from a feed convey-
or. The oversized material is scalped to a jaw crusher,
where it is reduced before it is returned to the feed con-
veyor. The material that passes through the scalping screen
is the lone product that is collected in a truck or bin
directly underneath the screen.
Additional product sizes may be produced by adding a
secondary crusher and modifying the screening arrangement.
This grouping that is commonly mounted on a single chassis
is known as a Duplex plant. As shown in Figure 2-15, pit
material is fed to the top of a triple-deck, inclined,
vibrating screen capable of producing three product sizes
and oversize which is reduced by a jaw crusher. Material
that is passed to the second screening deck is delivered to
a double- or triple-roll crusher for secondary reduction.
The output from both crushers is conveyed to a rotating
drum-type elevator that returns the material to the feed
2-47
-------
TRIPLE ROLL CRUSHER
JAW CRUSHER
FEED HOPPER
to
I
.&.
00
FINISHED PRODUCT
*
\
Figure 2-15. Portable Plant
(Courtesy of Pit and Quarry Handbook).
-------
conveyor. Material passing through the second screen to the
third is classified by size, collected in bins, and conveyed
to storage piles. Combination plants have two or more
chassis with various combinations of processing units.
Portable plants may be used as auxiliary units to large
stationary primary crushers in quarries that produce pit
material too large for the portable plant to handle alone.
The ability of some portable plants, however, is too limited
to accept the feed from the larger primary crushers.
Therefore, a secondary or intermediate crusher, which may
also be a portable unit, is required to take full advantage
of the capability of the primary crusher.
Conversely, some process conditions preclude the need
for an intermediate crusher, and the flexibility of indivi-
dual portable processing units allows the user to meet his
product requirements simply by arranging the units in the
most efficient combination.
Emissions from each processing unit in a portable plant
are the same as those from a unit of equivalent size in a
stationary plant.
2-49
-------
REFERENCES FOR CHAPTER 2
Characterization of Particulate Emissions from the
Stone- Processing Industry. Prepared by Research
Triangle Institute for the U.S. Environmental Pro-
tection Agency. Contract No. 68-03-0607, Task No. 10.
May 1975. p 11.
Compilation of Air Pollutant Emission Factors, 2nd
Edition. U.S. Environmental Protection Agency, Pub-
lication No. AP-42. April 1973. p. 8.20-1.
Technical Guidance for Control of Industrial Process
Fugitive Particulate Emissions. Environmental Pro-
tection Agency, Research Triangle Park, North Carolina.
Publication No. EPA-450/3-77-010. March 1977.
Pit and Quarry Handbook and Purchasing Guide, 63rd
Edition. Pit and Quarry Publications, Incorporated,
Chicago. 1970. p. B-17.
Chemical Engineers' Handbook, 3rd Edition. Robert H.
perry, (editor). McGraw-Hill, New York. 1950. p.
1127.
Ratcliffe, A. Trends in Size Reduction of Solids
Crushing and Grinding. Chemical Engineering. July 10,
1972. pp 62-75.
Rundquist, W.A. The Portable Plant...A Versatile,
Hard-working Tool. Pit and Quarry. May 1974.
2-50
-------
3.0 EMISSION REDUCTION TECHNIQUES
Diverse particulate emission sources in stone-processing
operations have resulted in the use of a variety of control
methods and techniques. Dust-suppression techniques are the
most commonly used. They are designed to prevent particu-
late matter from becoming airborne and are applicable to
both process and fugitive dust sources. Particulate emis-
sions such as those generated by crushing operations can be
captured in collection systems. Emission sources and appli-
cable control options are listed in Table 3-1.
3.1 CONTROL OF QUARRYING OPERATIONS1
3.1.1 Control of Drilling Operations
Generally, two methods are available for controlling
particulate emissions from drilling operations: water injec-
tion and aspiration to a control device.
Water injection is a wet-control technique in which
water or water plus a wetting agent or surfactant, usually a
liquid detergent, is forced into the compressed air stream
that flushes the drill cuttings from the hole. The injec-
tion of fluid into the airstream produces a mist that dampens
the stone particles and causes them to agglomerate. As the
3-1
-------
Table 3-1. EMISSION SOURCES AND CONTROL OPTIONS
Operation or source
Control options
Drilling
Blasting
Loading
Hauling (emissions from
roads)
Crushing
Screening
Conveying (transfer
points)
Stockpiling
Conveying
Windblown dust from
stockpiles
Windblown dust from roads
Liquid injection (water or
water plus a wetting agent).
Capturing and venting emissions
to a control device.
No control.
Water wetting.
Water wetting.
Treatment with surface agents.
Soil stabilization.
Paving.
Traffic control.
Wet-dust suppression systems.
Capturing and venting emissions
to a control device.
Same as for crushing.
Same as for crushing.
Stone ladders.
Stacker conveyors.
Water sprays at conveyor discharge,
Covering.
Wet dust-suppression.
Water wetting.
Surface active agents.
Covering.
Windbreaks.
Oiling.
Surface active agents.
Soil stabilization.
Paving.
Sweeping.
3-2
-------
particles are blown from the hole, most of them drop at the
drill collar as damp pellets rather than becoming airborne.
The addition of a wetting agent increases the wetting
2
ability of untreated water by reducing its surface tension.
This reduces the amount of water required for effective
control, thereby minimizing the drawbacks of decreased
penetration rate, increased wear, restricted chip circula-
tion, increased back pressure at the bottom of the hole, and
potential collaring (drill sticking in the hole). The
amount of solution required is dependent upon the size of
the hole, the drilling rate, and the type of material being
drilled. A typical injection rate for an 89-mm (3-1/2-inch)
diameter hole is about 26.5 liters/h (7 gal/h). The effec-
tive application of water injection to a drilling operation
should eliminate visible emissions.
Dry collection systems also are used to control emis-
sions from the drilling process. A shroud or hood encircles
the drill rod at the hole collar. A vacuum captures emis-
sions and vents them through a flexible duct to a control
device for collection. Control devices most commonly used
are cyclones or fabric filters preceded by a settling cham-
ber. Cyclone collection efficiencies usually are not high.
Although designed well for the collection of coarse- to
medium-sized particles (15 to 40 ym or larger), cyclones are
3-3
-------
generally unsuitable for fine particulates (10 ym and
smaller) because their collection efficiencies seldom exceed
80 percent in this size range. Fabric filter collectors,
however, exhibit collection efficiencies in excess of 99
percent through the submicron particle range. Air volumes
required for effective control may range from 0.235 to 0.705
m /s (500 to 1500 ft /min) depending on the type of rock
drilled, hole size, and penetration rate. A rotary drill
equipped with a baghouse was tested for visible emissions
from the capture system and the baghouse outlet. For more
than 75 percent of the time, the opacity was less than 20
percent at the capture point. Readings at the baghouse
ranged from 0 to 5 percent. The test data are in Appendix
A.
3.1.2 Control of Blasting Operations
No effective method is available for controlling parti-
culate emissions from blasting. Good blasting practices can
minimize noise, vibration, and air shock. Multidelay deton-
ation devices, which detonate the explosive charges in
millisecond time intervals, can reduce these ef-fects.
Scheduling blasting operations so that they occur only
during conditions of low wind and low inversion potential
can substantially reduce the impact of emissions from this
source.
3-4
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3.1.3 Control of Quarry Loading Operations
Particulate emissions from the loading of broken rock
by loaders or shovels are estimated to be 0.025 kg/Mg of
stone (0.05 Ib/ton). These emissions are difficult to con-
trol. However, some control may be attained by using water
trucks equipped with hoses or portable watering systems to
wet down the piles prior to loading.
3.1.4 Control of Hauling Operations
As indicated in Chapter 2, a large portion of the
fugitive dust generated by quarrying operations results from
the transportation of broken rock from the quarry to the
processing plant over unpaved haul roads. Because haul
roads are temporary highways to accommodate advancing quarry
faces, they usually are unimproved. Emissions from hauling
operations are proportional to the condition of the road
surface and the volume and speed of vehicular traffic.
Consequently, control measures include methods to improve
road surfaces or suppress dust and operational changes to
minimize the effect of vehicular traffic.
Various treatment methods applied to control fugitive
emissions from haul roads include watering, surface treat-
ment with chemical dust suppressants, soil stabilization,
and paving. The most common method is watering. Water is
applied to the road in a controlled manner by operators of
water trucks equipped with either gravity-fed spray bars or
pressure sprays. The amount of water required, frequency of
3-5
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application, and effectiveness are dependent on the weather,
the conditions of the roadbed, and the willingness of the
operator to allocate the resources required to do an effec-
tive job.
On warm and windy days frequent watering may be neces-
sary because of rapid evaporation, whereas after a rainfall
it may not be necessary. If watering is excessive, it can
create hazardous road conditions for haul vehicles.
Road dust can also be controlled by periodic applica-
tion of wet or dry surface-treatment chemicals for dust
suppression. Road surfaces are commonly treated with oil,
usually supplemented by watering. Waste oils such as
crankcase drainings are spread over roadways at a rate of
225
about 0.23 liter/m (0.05 gal/yd ) of roadway. The fre-
quency of application may range from once per week to only
several times per season, depending on the temperature,
wind, and rainfall in the area. This treatment also must be
used judiciously because excessive application can cause
slippery, dangerous road conditions.
Other treatments include the application of hygroscopic
chemicals (substances that absorb moisture from the air)
such as organic sulfonates and calcium chloride (CaCl2)-
When spread directly over unpaved road surfaces, these
chemicals dissolve in the moisture they absorb and form a
3-6
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clear liquid that is resistant to evaporation. Consequently,
they are most effective in areas of relatively high humidity.
Because the chemicals are water soluble, however, they may
have to be applied repeatedly in areas of frequent rainfall.
Also, these agents may contribute to the corrosion of expen-
sive haul vehicles.
An alternative to surface treatment is soil stabiliza-
tion. Stabilizers usually consist of a water dilutable
emulsion of either synthetic or petroleum resins that act as
an adhesive or binder. Quarry operators in California
and Arizona report substantial success with one such agent
called Coherex.* This product is a nonvolatile emulsion
containing about 60 percent natural petroleum resins and 40
percent wetting solution. The use of Coherex* in the initial
treatment of new roads depends on the characteristics of the
road bed and the penetration depth required. For most
roads, an effective dilution is one part Coherex to four
parts of water (1:4) applied at a rate of about 9.1 to 22.7
2 2
liters/in (2 to 5 gal/yd ). Once the road has been stabil-
ized by repeated application and compaction of vehicle
traffic over a period of a few weeks, the dilution may be
increased to 1:7 to 1:20 for daily maintenance. Detailed
The use of trade names or commercial products does not
constitute endorsement or recommendation for use by the
Environmental Protection Agency.
3-7
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data on the application rate are not available; usually one
pass per day is considered sufficient for effective dust
control. In addition to the environmental benefits obtained
by using stabilizers rather than traditional watering methods,
considerable savings and operating advantages are reported
by users. These include reduced labor costs, lower mainten-
ance costs on haul vehicles, and safer road conditions.
Paving is probably the most effective means of reducing
particulate emissions, but the least practical. Initial
cost may exceed $20,000/1.61 km ($20,000/mile) for a 76.7-
mm (3-in.) bituminous surface, and maintenance and repair
costs may be relatively high because of the damage inflicted
g
by heavy vehicle traffic. No study has been made to deter-
mine the relative cost-effectiveness of the various control
options.
Operational measures that would reduce emissions
include the reduction of traffic volume and control of
traffic speed. Replacing smaller haul vehicles with larger
capacity units would minimize the number of trips required
and thus effectively reduce total emissions per ton of rock
hauled. A stringent program to control traffic speed would
also reduce dust emissions. According to a study of emissions
from conventional vehicle traffic on unpaved roads, a reduc-
tion in the average vehicle speed from 48 km/h (30 mph)
[for which an emission level of 1.68 kg (3.7 Ib) per vehicle
3-8
-------
mile was established] to 40, 32, and 24 km/h (25, 20, and 15
g
mph) reduced emissions by 25, 33, and 40 percent, respectively.
Although the situations may not be completely analogous, it
can be concluded that an enforced speed limit of 8 to 16
km/h (5 to 10 mph) would reduce fugitive dust emissions from
quarry vehicle traffic and provide additional benefits such
as increased safety conditions and longer vehicle life.
Additional haul trucks may be required to maintain the pro-
duction rate. However, the number of trucks required is not
determinable because trucks may stand idle while waiting to
be loaded.
3.2 CONTROL OF PLANT OPERATIONS
Typical crushed-stone plants contain a multiplicity of
dust-producing points, including numerous crushers, screens,
conveyor transfer points, and storage facilities. Control
methods generally applied to plant-generated emissions
include wet dust suppression, dry collection, and a combina-
tion of the two. Wet dust suppression consists of intro-
ducing moisture into the material flow to restrain fine
particulate matter from becoming airborne. Dry collection
involves hooding or enclosing dust-producing points and
exhausting emissions to a collection device. In combination
systems both methods are applied at different stages through-
out the process. Completely enclosing process equipment is
another very effective technique.
3-9
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3.2.1 Wet Dust Suppression
In a wet dust-suppression system, dust emissions are
controlled by applying moisture to the crushed material at
critical dust-producing points in the process flow. This
causes dust particles to adhere to large stone surfaces or
to form agglomerates too heavy to become or remain airborne.
Thus, the objective of wet dust suppression is not to fog an
emission source with a fine mist to capture and remove
particulates emitted, but rather to prevent their emission
by keeping the material moist at all process stages. Exces-
sive moisture can cause blinding of screen surfaces and
thereby reduce both their capacity and effectiveness, or it
can cause coating of stone surfaces and result in a marginal
or nonspecification product. Antifreeze agents may be used
during cold temperatures to prevent freezing. Small quan-
tities of specially formulated wetting agents or surfactants
are often blended with the water to reduce its surface
tension and improve its wetting efficiency so that dust
generation may be suppressed with a minimum of "added mois-
ture." Although these agents may vary in composition, their
molecules are characteristically composed of two groups, a
hydrophobic group (usually a long-chain hydrocarbon) and a
hydrophylic group (usually a sulfate, sulfonate, hydroxide,
or ethylene oxide). When introduced into untreated water
2
(surface tension 72.75 dynes/cm at 20°C), these agents
3-10
-------
effect an appreciable reduction in its surface tension (to
3 9
as low as 27 dynes/cm ). The dilution of such an agent in
water (1 part wetting agent to 1000 parts water) is reported
to make dust control effective throughout an entire crushed-
stone plant with as little as 1/2 to 1 percent total added
moisture per megagram (ton) of stone processed.
In adding moisture to the process flow, it is usually
necessary to apply it at several points. Treatment should
begin as soon as possible after the material to be processed
is introduced into the plant. Normally, the initial appli-
cation is made at the primary crusher truck dump through the
use of spray bars located either on the periphery of the
dump hopper or above it. This application significantly
reduces intermittent visible dust emissions generated during
dumping operations. Applications are also made at the
discharge of the primary crusher and all secondary and
tertiary crushers where new dry surfaces and dust are gen-
erated by the fracturing of stone in the crusher. Treatment
may also be required at feeders located under surge or
reclaim piles if moisture evaporation from this temporary
storage is significant. If the material is conditioned
properly at these points, further applications at screens,
conveyor transfer points, conveyor and screen discharges to
bins, and conveyor discharges to storage piles may not be
necessary because moist stone exhibits a carryover dust
3-11
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control effect that permits it to be handled through a
number of operations without dusting. The amount of mois-
ture required at each application point depends on the type
of wetting agent used and its dilution ratio in water, the
1 ,
type and size of process equipment used, and the character-
istics of the material processed (rock type, size distribu-
tion, feed rate, and moisture content).
A typical wet dust-suppression system (illustrated in
Figure 3-1) contains the following basic components and
features: a dust control agent, proportioning equipment,
a distribution system, and control actuators. A proportioner
and pump are necessary to mix the wetting agent and water at
the desired ratio and to provide the moisture in sufficient
quantity and at adequate pressure to meet the demands of the
overall system.
Distribution is accomplished by spray headers fitted
with pressure spray nozzles. One or more headers are used
to apply the dust-suppressant mixture at each treatment
point at the rate and spray configuration required to con-
trol the dust effectively. The nozzle type used, hollow-
cone, solid cone, or fan, depends on the spray pattern
desired. Screen filters are used to prevent nozzle plug-
ging. Figure 3-2 shows a typical arrangement for the con-
trol of dust emissions at a crusher discharge.
3-12
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CJ
TRUCK DUMP
SECONDARY
CRUSHER
PRIMARY CRUSHER
TERTIARY
CRUSHER
INCOMING WATER LINE
O
DUST CONTROL AGENT
PROPORTIONER
Figure 3-1. Wet dust-suppression system.
11
-------
SUPPRESSANT
Figure 3-2. Dust suppression application at crusher discharge.
3-14
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Spray actuation and control are important to achieve
effective control and to reduce waste and undesirable muddy
conditions, especially when the material flow is intermittent,
Spray headers at each application point are normally equipped
with an on-off controller that is interlocked with a sensing
mechanism so that sprays will be operative only when material
is flowing. Systems are also commonly designed to operate
under all weather conditions. Exposed pipes are usually
traced with heating wire and insulated to provide protection
from freezing.
One manufacturer claims emissions can be controlled at
better than 90 percent efficiency from primary crusher to
stockpile with a well-designed wet dust-suppression system.
Because these unconstrained emissions cannot be tested, no
actual particulate emission measurements have been made to
verify or dispute this contention.
3.2.2 Dry Collection Systems
Particulate emissions generated at plant facilities
(crushers, screens, conveyor transfer points, and bins) may
be controlled by capturing and exhausting emissions to a
collection device. Depending on the physical layout of the
plant, emission sources may be manifolded to one centrally
located collector or to strategically placed units. Collec-
tion systems consist of hoods and enclosures to confine and
capture emissions and ducting and fans to convey the
3-15
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captured emissions to a collection device where they are
removed before the airstream is exhausted to the atmosphere.
Exhaust Systems —
If a collection system is to effectively prevent parti-
culate emissions from being discharged to the atmosphere,
its hooding and ducting must be properly designed and balanced.
Process equipment should be enclosed as completely as
practicable, yet allow access room for routine maintenance
and inspection requirements. For crushed-stone facilities,
recommended hood face or capture velocities may range from
12
1 to 2.5 m/s (200 to 500 ft/min). In general, a minimum
indraft velocity of 1 m/s (200 ft/min) should be maintained
through all open hood areas. Properly designed hoods and
enclosures minimize exhaust volume and, consequently, power
requirements. Proper hooding will also minimize the effects
of cross drafts (wind) and the effects of induced air (i.e.,
air placed in motion as a result of machine movement or
falling material). Good duct design dictates that adequate
conveying velocities be maintained so that the transported
dust particles will not settle in the ducts along,the way to
the collection device. Conveying velocities recommended for
crushed-stone particles range from 17.8 to 22.9 m/s (3500 to
4500 ft/min),12
Completely adequate construction specifications are
available and have been utilized to produce efficient, long-
3-16
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lasting systems. Various guidelines have been established
for minimum ventilation rates required to control emissions
from crushing plant facilities. The following are ventila-
tion rates most commonly utilized in the industry, based
upon these guidelines.
Conveyor transfer points —
At belt-to-belt conveyor transfer points, hoods should
be designed to enclose both the head pulley of the upper
belt and the tail pulley of the lower belt as completely as
possible. The open area should be reduced to about 0.152
22 13
m /m (0.5 ft /ft) of belt width to achieve the proper design.
Air volume to be exhausted is affected by conveyor belt
speed and free-fall distance to which the material is subjected,
3 3
Recommended exhaust rates are 0.55 m /s per m (350 ft /min
per ft) of belt width for belt speeds less than 1.0 m/s (200
ft/min) and 0.24 m /s (500 ft /min) for belt speeds exceeding
14
1.0 m/s (200 ft/min). For a belt-to-belt transfer with
less than a 0.91 m (3 ft) fall, the enclosure illustrated in
Figure 3-3 is commonly used.
For belt-to-belt transfers with a free-fall distance
greater than 0.91 m (3 ft) and for chute-to-belt transfers,
an arrangement similar to that depicted in Figure 3-4 is
commonly used. The exhaust connection should be made as far
downstream as possible to maximize dust fallout and thereby
minimize needless dust entrainment. For very dusty material,
3-17
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EXHAUST TO
CONTROL DEVICE
FLEXIBLE RUBBER
SKIRT
Figure 3-3. Hood configuration for a 'transfer point having
a fall less than 0.91 ra (3 ft).
3-18
-------
UI
I
AGGREGATE CHUTE
TO CONTROL
DEVICE
TAIL PULLEY
SLOT VENT
TO CONTROL
DEVICE
SHEET METAL
ENCLOSURE
CONVEYOR
BELT
Figure 3-4. Hood configuration for a transfer point having a fall
greater than 0.91 m (3 ft).
-------
additional exhaust air may be required at the tail pulley of
the receiving belt. Recommended air volumes are 0.33 m /s
(700 ft3/min) for belts 0.91 m (3 ft) wide and less, and 0.47
m3/s (1000 ft3/min) for belts wider than 0.91 m (3 ft).14
Transfers from belt or chute to bin differ from the
usual transfer operation in that no open area is downstream
of the transfer point. Thus emissions occur only at the
loading point. At some point, normally remote from the
loading point, air is exhausted from the bin at a minimum
33 2
rate of 0.094 m /s (200 ft /min) per ft of open area at the
14
loading point.
Screens —
Screening surfaces can be fully hooded to control
emissions. The exhaust volume required varies with the
surface area of the screen and the amount of open area
between the screen and its enclosure. A well-designed
enclosure should have no more than 50.8 to 101.6 mm (2 to 4
in.) of space around the periphery of the screen. A minimum
323 2
exhaust rate of 0.25 m /s per m (50 ft /min per ft ) of
screen area is commonly used, with no increase for multiple
14
decks. Oversize discharge points that require additional
ventilation should be treated as regular transfer points and
exhausted accordingly.
3-20
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Crushers —
Hooding and air volume requirements for the control of
crushers are quite variable. The only established criterion
is that a minimum indraft velocity of 1.0 m/s (200 ft/min)
be maintained through all open hood areas. To achieve this,
control velocities in excess of 2.5 m/s (500 ft/min) may be
necessary to overcome induced air movement resulting from
the material flow and mechanical motion. For effective
control of emissions, ventilation should be applied at both
feed and discharge points of the crusher. An exception to
this would be at primary jaw or gyratory crushers because it
is necessary to have ready access to the crusher feed opening
to dislodge large rocks that may get stuck. No plant is
known to use a baghouse at this point.
In general, crusher feed should be enclosed as com-
pletely as possible and exhausted according to the criterion
established for transfer points. The crusher discharge to
the conveyor belt should also be totally enclosed. The ex-
haust rate, however, may vary considerably depending on
crusher type. For impact crushers, exhaust volumes may
range from 1.88 to 3.76 m3/s (4000 to 8000 ft3/min) ,15 For
compression-type crushers, an exhaust rate of 0.78 m /s per
m (500 ft /min per ft) of discharge opening should be suf-
ficient. In either case, pickup should be applied down-
stream of the crusher at a distance of at least 3.5 multi-
plied by the width of the receiving conveyor.
3-21
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Collection Devices —
The most commonly used dust collection device in the
crushed-stone industry is the fabric filter, or baghouse.
Fabric filters are used for most crushing plant applications.
The fabric filters that are equipped with a mechanical
shaker require periodic shutdown for cleaning every 4 or 5
hours of operation. These units, normally equipped with
cotton sateen bags, are operated at an air-to-cloth ratio
ranging from 2:1 to 3:1. A cleaning cycle, which requires
no more than 2 to 3 minutes of bag shaking, is normally
actuated when the plant is not operating.
If it is impractical to turn off the collector, fabric
filters with continuous cleaning are employed. Although
compartmented, mechanical-shaker types may be used, jet-
pulse units are preferred. These units usually use a fil-
tering medium of wool or synthetic felt, and they may be
operated at filtering ratios as high as 6:1 to 10:1. With
either type of baghouse, greater than 99 percent efficiency
can be attained, even on submicron particle sizes. During
EPA emission tests at a variety of crushed-stone facilities,
outlet grain loadings were seldom recorded in excess of 0.023
g/dry m (0.01 gr/dscf). (See Section 3.5 and Appendix A
for details.)
Other collection devices used in the industry include
cyclones and low-energy scrubbers. Although these collectors
3-22
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may demonstrate high efficiencies (95 to 99 percent) for
coarse particles (40 ym and larger), they are less efficient
3
for medium and fine particles (20 ym and smaller) . Although
high-energy scrubbers and electrostatic precipitators could
conceivably achieve results similar to those of a fabric
filter, these devices are not used currently in the industry.
3.2.3 Combination Control Systems
Wet dust-suppression and dry collection techniques are
often used in combination to control particulate emissions
from crushed stone facilities. As illustrated in Figure
3-5, wet dust-suppression techniques are generally used to
control emissions at the primary crushing stage and at
subsequent screens, transfer points, and crusher feeds. Dry
collection is generally used to control emissions at sec-
ondary and tertiary crusher discharges, where new dry stone
surfaces and fine particulates are formed. A large portion
of the fine particulates is removed by dry collection, but
subsequent dust suppression applications become more effec-
tive with a minimum of added moisture. Depending on the
production requirements, dry collection may be the only
method that can be used at the finishing screens.
3.2.4 Control of Portable Plants
Control of emissions from a portable plant is difficult
compared with that from a stationary one. However, minimal
3-23
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TRUCK DUMP
AND FEEDER
BAG
COLLECTOR
PRIMARY
CRUSHER SECONDARY
^ CRUSHER
SCREEN
BIN AND TRUCK
LOADING STATION
SUPPRESSION
COLLECTION
STORAGE
PILE
TERTIARY
CRUSHER
Figure 3-5. Combination control system.
11
3-24
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visible emissions have been reported from the successful
application of a wet dust-suppression system. Also,
trailer-mounted portable baghouse units are commercially
available and have been applied to control emissions from
portable plants. In Pennsylvania, most portable plants use
a wet dust-suppression system.
3.3 CONTROL OF FUGITIVE DUST SOURCE
Uncontrolled fugitive dust emissions constitute a signi-
ficant portion of the pollution problem in the crushed-stone
industry. Control measures to reduce fugitive dust emissions
from quarrying operations (blasting, loading, and hauling)
were discussed in Section 3.1. A review of the control
measures applied to other fugitive sources is presented
here.
3.3.1 Control of Aggregate Storage Piles
Significant fugitive dust emissions, as judged by
visible emissions, may result during the formation of new
aggregate piles and the erosion of previously formed piles.
During the formation of stockpiles by stacking conveyors,
particulate emissions are generated by wind blowing across
the streams of falling stone and segregating fine particles
from coarse particles. Emissions are also produced when the
falling stone impacts on the piles. Control methods include
wet dust suppression and devices designed to minimize the
free-fall distance to which the material is subjected, thus
3-25
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lessening its exposure to wind and reducing emissions gener-
ated upon impact.
The wet dust-suppression effect is carried over at
plants that spray the discharge from the final crushing or
screening operation, after which no new surfaces are created
nor the material tumbled. Control devices that are applied
include stone ladders, telescopic chutes, and hinged-boom
stacker conveyors. A stone ladder simply consists of a
section of vertical pipe into which stone from the stacking
conveyor is discharged. At different levels the pipe has
square or rectangular openings through which the material
may flow. This reduces the effective free-fall distance and
affords wind protection. Another approach is the telescopic
chute. Material is discharged to a retractable chute and
falls freely to the top of the pile. As the height of the
stockpile increases or decreases, the chute is gradually
raised or lowered accordingly. A similar approach is pro-
vided by a stacker conveyor equipped with an adjustable
hinged boom that raises or lowers the conveyor according to
the height of the stockpile.
Watering is the most commonly used technique for con-
trolling windblown emissions from active stockpiles. A
water truck equipped with a hose or other spray device may
be used. One operator uses spray towers in the stockpile
3-26
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areas. The towers are equipped with Rainbird*-type spray
nozzles capable of spraying water at 31.6 liters/s (500
gal/min) in a continuous circle with a 61.0 m (200 ft) radius.
Only three passes are required to effectively wet down a
pile.5
Locating stockpiles behind natural or manufactured wind-
breaks also aids in reducing windblown dust. Also, the
working area of active piles should be located on the leeward
side of the pile. Very fine materials or materials that
must be stored dry can be controlled effectively only through
the use of suitable stockpile enclosures or silos, even
though these may create load-out problems.
The application of soil stabilizers, which are pri-
marily petroleum or synthetic resins in emulsion, has been
reasonably effective for storage piles that are inactive for
long periods of time and for permanent waste piles or spoil
banks. These chemical binders cause the surface particles
i
to adhere to one another, forming a durable wind and rain
resistant crust (relatively insoluble in water). As long as
this crust remains intact, the stockpile is protected from
wind erosion.
Mention of company product names is not to be considered
as an endorsement by the U.S. Environmental Protection
Agency.
3-27
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3.3.2 Control of Conveying Operations
In addition to the emissions generated at transfer
points, fugitive dust emissions may result from conveying
operations.
Dust-control alternatives include chemical suppression
and covering. As noted in Section 3.2.1, a carryover, dust-
proofing effect will result from previous applications of
dust suppressants. It is unlikely, however, that this
carryover effect is sufficient to afford effective control
during periods of high wind and low humidity or when
handling fine materials. Ultimately, the most effective
measure is to cover open conveyors because covers provide
protection from wind and an opportunity for airborne par-
ticles to fall out. In addition to providing dust control,
covered conveyors also yield certain operating benefits.
•
They increase a plant's capability to operate during periods
of inclement weather by reducing the potential for mud cake
buildup on belts. This buildup can damage conveyors and
result in hazardous operating conditions, screen blinding,
and the production of nonspecification products as*a result
of the retention of fines. Conveyor covers must be removed
during conveyor breakdowns, which are rare.
3.3.3 Control of Load Out Operations
The transfer of fine materials from stockpiles or
storage bins into open dump trucks may generate significant
3-28
-------
fugitive dust emissions as judged by visible emissions.
These operations are currently uncontrolled except for some
attempts to wet the material either prior to or during
loading. Dust formation may be reduced if the stone is kept
wet on the stockpiles and the loaded buckets are emptied as
close as possible to the truck beds.
At some installations, water spray systems are used to
wet the stone in the truck when loading out of bins.
Enclosing the area under the bins as much as possible will
also reduce the potential for windblown emissions. In con-
crete-batch plants, exhaust systems with canopy type hoods
are sometimes applied to control dust emissions from bin
load-out operations. In concrete-batch plants, exhaust
systems with canopy type hoods are sometimes applied to
control dust emissions from bin load-out operations; how-
ever, no such application has, been found in the crushed-
stone industry. Operators contend that such a system would
be impractical because of the variability in the bed size of
the trucks loaded.
3.3.4 Control of Yard and Other Open Areas
Fugitive dust emissions from plant yard areas are
generated by vehicular traffic and wind. These emissions
generally are not controlled at crushed-stone plants.
Emissions from these areas can be controlled by maintaining
3-29
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good housekeeping practices. Spillage and other potential
dust sources should be cleaned up. Street-sweeping equip-
ment has been effective for paved or other smooth yard
surfaces. The same control measures applied to quarry haul
roads can be used for intraplant roads subject to high
traffic volume. Treatment with soil stabilizers and planting
of vegetation offer viable control options for large open
areas and overburden piles. Many chemical stabilizers
presently on the market promote the growth of vegetation and
18
offer effective control against rain and wind erosion.
3.4 FACTORS AFFECTING THE PERFORMANCE OF CONTROL SYSTEMS
3.4.1 Dust Suppression
Factors that may affect the performance of a wet dust-
suppression system include the particular wetting agent
used, the method of application, characteristics of the
process flow, and the type and size of the process equipment
serviced. The number, type, and configuration of spray
nozzles at an application point, as well as the speed at
which a material stream moves past that point, may affect
both the efficiency and uniformity of wetting. Meteoro-
logical factors such as wind, ambient temperature, and
humidity, which affect the evaporation rate of added mois-
ture, may also adversely affect the overall performance of a
dust-suppression system. When the material processed
3-30
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contains a high percentage of fines, such as the product
from a hammermill, dust-suppression applications may be
essentially inefffective because of the enormous surface
area to be treated.
3.4.2 Dry Collection
In dry collection systems, factors affecting both
capture and collection efficiency are important. Wind
blowing through hood openings can significantly reduce the
effectiveness of a local exhaust system. This is signifi-
cant because an indraft velocity of 1 m/s (200 ft/min) is
equivalent to less than 3.7 km/h (2.3 m/h) ; consequently, it
may be necessary to enclose process equipment at instal-
lations that are subject to buffeting by high prevailing
winds.
An exhaust system must be properly maintained and
balanced if it is to remain effective. Good practice
dictates that systems be periodically inspected and that
capture and conveying velocities be checked against design
specifications to assure that the system is functioning
properly. Abrasion which produces leaks and poorly de-
signed ducts that permit material to accumulate are the two
primary causes of unbalanced flow in an exhaust system.
Bag cleaning has a significant effect on performance.
Inadequate cleaning causes fabric filters to blind, result-
3-31
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ing in excessively high pressure drops. Cleaning too fre-
quently or too vigorously results in excessive bag wear and
the formation of leaks. Overcleaning may also prevent the
formation of an adequate filter cake and, thus, lowers the
collection efficiency. The importance of following manu-
facturers ' recommended operating and maintenance procedures
cannot be overstressed.
Emission tests were carried out by EPA on 12 bag-
house units at seven crushed-stone installations that process
a variety of rock types, including limestone, traprock, and
cement rock. These tests indicated that the size distribu-
tion of particulates collected, the rock type processed, and
the facilities controlled (crushers, screens, and transfer
points) do not substantially affect baghouse performance
(see Appendix A - Source Test Data).
3.4.3 Combination Systems
Factors affecting the performance of combination sys-
tems are identical to those encountered when dust-suppression
or collection systems are used alone.
3.4.4 Retrofit Control Systems
Space availability is a major factor in retrofitting a
control system. Often, little space is available at plants
located in urban or congested areas. Space limitation is
not a problem for crushed-stone plants, except that some
existing plants may require longer duct runs.
3-32
-------
Other major factors affecting retrofit are the avail-
ability of utilities (electricity and water) and any
required modifications to the existing plant. Little plant
modification is required for retrofitting wet dust-suppression
systems or dry collection systems to existing crushed-stone
plants. Very little additional power is required for wet
dust-suppression systems. Dry collection systems may
require up to 22 percent additional power. Additional gen-
erators may have to be installed at portable plants to meet
this demand.
Retrofit systems generally require more engineering
time than would be required for incorporating a control
system into a new installation. Because construction equip-
ment and labor are brought in just for installing the
control system, the installation costs are high. In addi-
tion, a loss of production occurs during retrofitting.
Crushed-stone plants that operate seasonally may be able to
schedule retrofitting during the off season. The most
important consideration in retrofitting, from a cost stand-
point, is the remaining plant life. Control equipment costs
are presented in Chapter 4.
A spokesman for a company that operates a number of
plants stated that they did not experience any special
problems in retrofitting wet dust-suppression or dry
3-33
-------
19
collection systems. Pennsylvania State Agency personnel
have not reported any special complaints, except that longer
duct runs are required in some cases.
3.5 PERFORMANCE DATA ON PARTICULATE EMISSION CONTROL
SYSTEMS2*
3.5.1 Dry Collection Systems
Particulate Emission Data —
Particulate emission measurements were conducted by EPA
on 12 baghouse collectors used to control emissions
generated at crushing, screening, and conveying transfer
points at five crushed-stone installations. Measurements
were also conducted on a baghouse unit that serves a drill-
ing operation at a limestone quarry. Table 3-2 briefly
summarizes the process facilities controlled by each bag-
house tested. Appendix A contains complete test data
summaries for both mass particulate measurements and visible
emission observations and a description of each process
facility tested.
Of the five plants tested, three processed limestone
rock (A, B, and C) and two processed traprock (D and E).
Four of the five were commercial crushed-stone operations
producing a variety of end products including dense-graded
road base stone, bituminous aggregates, concrete aggregates
and nonspecific construction aggregates. In addition,
plant B produced about 60 tons/h of agstone. Facilities
3-34
-------
Table 3-2. PROCESS FACILITIES CONTROLLED BY BAGHOUSE UNITS TESTED
Ul
I
U)
Ul
Facility
Al
A2
A3
A4
Bl
B2
Cl
C2
Dl
02
El
E2
F
Rock type
processed
Limestone
Limestone
Limestone
Limestone
Limestone
Limestone
Limestone
Limestone
Traprock
Traprock
Traprock
Traprock
Limestone
Baghouse specifications
Type
Jet Pulse
Jet Pulse
Jet Pulse
Jet Pulse
Shaker
Shaker
Shaker
Shaker
Shaker
Shaker
Jet Pulse
Jet Pulse
Shaker
Filtering
Ratio
5.3 to 1
7 to 1
7 to 1
5.2 to 1
3.1 to 1
2.1 to 1
2.3 to 1
2.0 to 1
2.8 to 1
2.8 to 1
5.2 to 1
7.5 to 1
2.5 to 1
Capacity,
Nm3/s (scfm)
12.44 (26472)
7.43 (15811)
1.10 (2346)
4.95 (10532)
2.72 (5784)
8.55 (18197)
3.51 (7473)
3.08 (6543)
14.98 (31863)
12.20 (25960)
6.93 (14748)
9.93 (2122)
0.31 (663)
Process facilities
controlled
Primary impact crusher
Primary screen
Conveyor transfer point
Secondary crusher (cone) and screen
Primary impact crusher
Scalping screen, secondary cone crusher.
hammer mill, two teriary cone crushers.
two finishing screens, five storage bins.
and six conveyor transfer points
Primary jaw crusher (discharge), scalping
screen, and hammer mill
Two finishing screens and two conveyor
transfer points
Scalping screen, secondary cone crusher,
two sizing screens, two tertiary cone
crushers, and several conveyor transfer
points
Finishing screen and several conveyor
transfer points
Two sizing screens, four teriary cone
crushers, and several conveyor transfer
points
Five finishing screens and eight storage bins
Rotary drill
-------
Al through A4 consist of process operations producing raw
material for the manufacture 6f portland cement. Facilities
Al and Bl are both impact crushers used for the primary
crushing of run-of-quarry limestone rock. Facility A3 is
somewhat unique in that it consists of a single conveyor
transfer point at the tail of an overland conveyor. As in-
dicated in Table 3-2, the remaining facilities tested
consisted of multiple secondary and teriary crushing and
screening operations, and adjunct conveyor transfer points.
These include one primary jaw crusher, three secondary
cone crushers, two hammer mills, eight teriary cone crushers,
19 screens, 13 product bins, and over 15 conveyor transfer
points.
The baghouses tested included both jet pulse and
mechanical shaker type units. In all cases, the shaker
type fabric filters used cotton sateen bags and were operated
at a 2:1 to 3:1 filtering ratio. The jet pulse units
tested were fitted with wool or synthetic fiber belted
bags. Air to cloth ratios ranged from about 5:1 to 7.5:1.
A minimum of three test runs, using EPA Method 5, were
conducted at each facility tested. Sampling was performed
only during periods of normal operation and was stopped and
restarted to allow for intermittent process shutdowns and
upsets (no stone). When the process weight rate was
3-36
-------
undeterminable at a specific process facility, as in most
instances, the process weight through the primary crushing
stage was monitored to assure that the plant was operating
at or near normal capacity. Moisture determinations on the
stone processed were also performed at each plant tested
(except for plant A) to ensure that control was effected by
the dust collection system and not moisture inherent in the
material processed. Each test run at Facility F was con-
ducted to coincide with the time required to drill one
blast hole.
Excluding the measurements made at Facility F, the
emission concentration of the control devices tested averaged
0.011 g/dry m3 (0.005 gr/dscf) and never exceeded 0.030 g/dry
o
m (0.013 gr/dscf). The results of the measurements performed
at Facility F (rotary drill) averaged 0.089 g/dry m3 (0.039
gr/dscf). It is suspected that because this collector utilized
a manually operated shaker mechanism for cleaning, it may have
been subjected to overcleaning and, consequently, poor filter
cake buildup.
Visible Emissions Data --
Visible emission observations were also made during the
emission tests previously described. The exhaust from each of
the fabric filters tested was observed for about 4 hours in
accordance with EPA Method 9 procedures. No visible emissions
were observed from the fabric filters at plants A, C, D, and E.
Slight emissions ranging from 0 to 5 percent opacity were
observed at Bl, B2, and F. The highest 6-minute average
3-37
-------
recorded at each of these facilities was 1.0, 0.8, and 4.2
percent opacity, respectively. Again, the performance level
achieved by the baghouse servicing facility F (rotary drill)
is suspect.
Observations of visible emissions were also made at the
capture hoods and enclosures installed on many of the process
facilities controlled by the baghouses tested at plants A, B
and D to determine the presence and opacity of emissions escaping
capture. Eight crushers, six screens, one conveyor transfer
point and one surge bin were observed at plants A, B and D.
Again, EPA Reference Method 9 was used. Table 3-3 lists the
specific process facilities observed and summarizes the results
obtained in terms of the percent of time over a stated
observation period that visible emissions occurred. Complete
data summaries are contained in Appendix A. In most cases
essentially no visible emissions were observed at adequately
hooded or enclosed process facilities. Where emissions were
observed, they were of short duration and seldom exceeded five
percent opacity.
As shown in Table 3-3, no visible emissions were observed
at six of the eight crushers at which visual observations were
made. The six crushers include a hammermill used to produce
agricultural limestone at plant B and five cone crushers used
for secondary and tertiary crushing at plants B and D. Visible
emissions at the remaining two crushers, which include a primary
impactor at plant A and a secondary cone crusher at plant B,
were observed less than 2 percent of the time and 10 percent of
the time respectively.
3-38
-------
TABLE 3-3 SUMMARY OF VISIBLE EMISSION OBSERVATIONS AT CAPTURE HOODS OR
ENCLOSURES ON CRUSHED-STONE PLANT PROCESS FACILITIES
Plant/Rock type processed
CO
i
CO
to
Process facility
Accumulated observation
time (minutes)
Accumulated emission
time (minutes)
Percent of time
with visible emission
A Crushed limestone
B Crushed limestone
0 Crushed stone
Primary Impact crusher discharge
Conveyor transfer point
Scalping screen
Surge bin
Secondary cone crusher No. 1
Secondary cone crusher No. 2
Secondary cone crusher No. 3
Hammer mill
3-deck finishing screen (L)
3-deck finishing screen (R)
No. 1 tertiary gyrasphere cone crusher
No. 2 tertiary gyrasphere cone crusher
Secondary standard cone crusher
Scalping screen
Secondary (2- deck) sizing screen
Secondary (3-deck) sizing screen
240
166
28?'
287
231
231
231
287
107
107
170
170
170
210
210
210
4
3
45
3
23
0
0
0
4
0
0
0
0
0
0
0
2
3
15
1
10
0
0
0
4
0
0
0
0
0
0
0
-------
At the six screens at which visual observations were made,
no visible emissions were observed at four and only slight
emissions (less than 4 percent of the time) x«7ere observed at
the fifth. At the sixth screen (scalping screen at plant B),
emissions were observed 15 percent of the time. When present,
visible emissions at the scalping screen were primarily observed
in the area of the shaker-drive motor rather than at the actual
screening surface. Emissions were recorded at the conveyor or
transfer point at plant A and the surge bin at plant B were
also slight, ranging from 3 to 4 percent of time.
WET DUST SUPPRESSION
Due to the unconfined nature of emissions from facilities
controlled by wet dust suppression techniques, the quantitative
measurement of mass particulate emissions at these facilities
is impractical. However, some assessment of the effectiveness
of this technique can be made by visual observation.
Visual observations were made at numerous process facilities
at five installations where particulate emissions generated
are controlled by wet dust suppression techniques. The installa-
tions included two portable plants (I and K) and three stationary
plants (G, H and J). Visual observations were made using both
EPA Reference Methods 9 and 22. The process facilities observed
included 12 crushers, 11 screens, 8 transfer points and 1 storage
bin. A summary of the results is presented in Table 3-4.
The results obtained indicate that emissions from crushers
are generally greater than those from non-crusher sources.
3-40
-------
TABLE 3 - 4
SUMMARY OF VISIBLE EMISSION OBSERVATIONS FROM CRUSHED STONE PROCESS FACILITIES
CONTROLLED BY WET DUST SUPPRESSION
OJ
Plant
Process Facilities
EPA Method
Observation time
(minutes)
22
Percent of tirce
Emissions visible
Observation time
(minutes)
EPA Method 9
Highest
Six-Minute Average
Average
Opacity
G
H
I
J
K
Primary Jaw Crusher
Scalping Screen
Secondary Impact Crusher
Secondary Screen
Tertiary Cone Crusher
Conveyor Transfer Point
Primary daw Crusner
Scalping Screen
Conveyor Transfer Point
Secondary Screen
Secondary Cone Crusher
Finishing Screens
Scalping Screen
Primary Jaw Crusher
Conveyor Transfer Point
Secondary Screens
Secondary Cone Crusher
Finishing Screens
Conveyor Transfer Point
Conveyor Transfer Point
Primary Jaw Crusher
Scalping Screen (2-deck)
Secondary Cone Crusher (4 1/2')
Secondary Screen
Secondary Cone Crusher (5 1/2')
Conveyor Transfer Point
Conveyor Transfer Point
Primary Jaw Crusher
Conveyor Transfer Point
Secondary Screen (3-deck)
Secondary Cone Crusher (4 1/4')
Storage Bin
20
—
20
60
--
60
60
60
60
120
30
120
120
30
30
120
30
120
60
60
60
120
30
120
30
120
120
30
120
120
30
120
69
--
96
0
--
1
53
36
49
0
95
0
3
93
12
9
99
0
0
2
5
0
68
10
25
0
0
65
2
0
100
0
102
60
60
60
120
60
120
120
120
120
120
120
120
120
60
120
120
120
60
60
120
120
120
120
120
120
120
120
120
120
120
120
21
12
15
0
25
3
18
10
14
2
39
< 1
3
17
5
5
17
1
0
3
3
0
5
4
15
0
0
11
4
0
23
2
11
10
11
0
13
< 1
8
4
9
1
26
0
2
11
2
1
14
< 1
0
< 1
1
0
4
< 1
e
0
0
8
< i
0
17
< 1
-------
Visual observations made at twelve crushers including jaw, impact
and cone type crushers showed that emissions were generally
continuous (visible about 70 percent of the time on average)
and typically exceeded 10 percent opacity. In contrast, emissions
from non-crusher sources (screens and conveyor transfer points)
were generally intermittent (visible less than 90 percent of the
time) and seldom exceeded five percent opacity.
Excluding the scalping screen and conveyor transfer point
observed at plant G and the scalping screen observed at plant
H, which were judged to have inadequate controls, the highest
six-minute average recorded using EPA Method 9 at non-crusher
sources was 5 percent. In general, the wet dust suppression
controls applied at the majority of crusher sources observed
were judged to be inadequate due to the poor positioning of
spray bars or the use of too few nozzles. In fact, of the 12
crushers observed, only the primary jaw crusher and secondary
cone crushers at plant J and the primary jaw crushers at plants
G and K were judged to have adequate controls with the highest
six-minute average recorded equalling 15 percent opacity.
3.5.3 Combination Control Systems
Performance levels of combination systems are identi-
cal to those when dust-suppression or collection sys±ems
are used alone.
3.5.4 Fugitive Dust Control Measures
No procedures are available for quantifying emissions
from fugitive dust sources. No visible emission test pro-
grams were conducted during this study.
3-42
-------
REFERENCES FOR CHAPTER 3
1. Standards Support and Environmental Impact Statement:
An Investigation of the Best Systems of Emission Re-
duction for Quarrying and Plant Process Facilities in
the Crushed- and Broken-Stone Industry. (Draft). U.S.
Environmental Protection Agency, Office of Air Quality
Planning and Standards. Research Triangle Park, North
Carolina. August 1975.
2. Dust Control in Mining, Tunneling, and Quarrying in the
United States, 1961 through 1967. Bureau of Mines
information circular, No. IC8407. March 1969. pp 11-
12.
3. Control Techniques for Particulate Air Pollutants.
U.S. Environmental Protection Agency, Publication No.
AP-51, January 1969.
4. Techanical Guidance for Control of Industrial Process
Fugitive Particulate Emissions. U.S. Environmental
Protection Agency, Research Triangle Park, North
Carolina. EPA-450/3-77-010. March 1977.
5. Minnick, J.L. Control of Particulate Emissions from
Lime Plants - A Survey. Journal of the Air Pollution
Control Association, Volume 21, No. 4. April 1971.
6. Chiaro, D.A. Significant Operating Benefits Reported
from Cement Quarry Dust Control Program. Pit and
Quarry. January 1971.
7. Conrock Controls Fugitive Dust Efficiently and Econom-
ically. Pit and Quarry. September 1972. pp 127-128.
8. Investigation of Fugitive Dust Volume I - Sources,
Emissions and Control. Prepared by PEDCo Environ-
mental, Inc., for the Environmental Protection Agency.
Contract No. 68-02-0044, Task 9. EPA-450/3-74-036a.
June 1974.
3-43
-------
9.
10
11
12
13.
14
15
16
17.
18
19
Weant, G.E. Characterization of Particulate Emissions
from the Stone-Processing Industry. Prepared by Re-
search Triangle Institute for the United States En-
vironmental Protection Agency. Contract No. 68-02-0607-
10. May 1975.
Products Literature on
System. Johnson-March
Pennsylvania. 1977.
Chem-Jet Dust-Suppression
Corporation, Philadelphia/
Courtesy of Johnson-March Corporation. Philadelphia/
Pennsylvania.
Hankin, M. Is Dust the Stone Industry's Next Major
Problem. Rock Products. April 1967.
Anderson, D.M. Dust Control Design by the Air Induc-
tion Technique. Industrial Medicine and Surgery.
February 1964. p 3.
American Conference of Govermental Industrial Hygien-
ists. Industrial Ventilation/ A Manual of Recommended
Practice, 10th edition. 1968.
Telephone conversation between A. Vervaert, EPA and J.
McCorkel/ Aggregates Equipment Incorporated/ January
28/ 1975.
Greesaman, J. Stone Producer Wins Neighbors' Accep-
tance. Roads and Streets, July 1970.
Private communication between A. Kothari of PEDCo
Environmental, Inc., Cincinnati/ Ohio/ and J. Benson
and N. Desai of Pennsylvania State Air Pollution Con-
trol Agency, Harrisburg, Pennsylvania. May 5/ 1978.
Armbrust, D.V., and J.D. Dickerson. Temporary Wind
Erosion Control: Cost and Effectiveness of 34 Com-
mercial Materials. Journal of Soil and Water Con-
servation. July-August 1971. p 154.
Private communication between A. Kothari of PEDCo
Environmental, Inc., Cincinnati/ Ohio/ and V. Snyder of
General Crushed Stone, Easton/ Pennsylvania. May 3/
1978.
3-44
-------
20. Private communication between A. Kothari of PEDCo
Environmental, Inc., Cincinnati, Ohio, and J. Castcline,
Johnson-March Corporation, Phildelphia, Pennsylvania.
May 3, 1978.
21. Reference 1. p. 4-28 thru 4-33.
3-45
-------
4.0 COSTS OF APPLYING THE TECHNOLOGY
The crushed-stone industry produces a high volume of a
low-value commodity. It is the largest nonfuel, nonmetallic
mineral industry in the United States with respect to both
total volume and value of production. Total production in
1977 was 829 million Mg (914 million short tons), valued at
over 2.2 billion dollars. Geographically, the industry is
highly dispersed, with all states except Delaware reporting
production. Section 4.1 describes the industry in terms of
types of products, production capacities, and average pro-
duction costs.
Sections 4.2 and 4.3 present investment and annual cost
estimates for controlling process and fugitive dust sources,
respectively. Unless stated otherwise, all costs are for
December 1976.
4.1 INDUSTRY CHARACTERIZATION
Table 4-1 lists according to size the number of crushed-
stone quarries operating in 1973 and indicates the amount of
production in each range. The distribution of production
among individual quarries is not uniform and ranges from
4-1
-------
Table 4-1. NUMBER AND PRODUCTION OF QUARRIES BY SIZE IN 1976'
Annual production,
Mg
Less than 22,676
22,676 to 45,350
45,351 to 68,026
68,027 to 90,702
90,703 to 181,405
181,405 to 272,108
272,109 to 362,811
362,812 to 453,514
453,515 to 544,217
544,218 to 634,919
635,920 to 725,623
725,624 to 816,326
816,327 and over
short tons
(Less than 25,000)
( 25,000 to 49,999)
( 50,000 to 74,999)
( 75,000 to 99,999)
(100,000 to 199,999)
(200,000 to 299,999)
(300,000 to 399,999)
(400,000 to 499,999)
(500,000 tO 599,999)
(600,000 to 699,999)
(700,000 to 799,999)
(800,000 to 899,999)
(900,000 and over)
Total
Number of
quarries
2030
705'
320
253
668
368
215
177
109
92
65
43
169
. 5214
Percent
of
total
38.9
13.5
6.2
4.9
12.8
7.1
4.1
3.4
2.1
1.8
1.2
0.8
3.2
100.0
Production
Thousand
megagrams
13,227
22,843
17,911
19,859
84,910
81,251
66,849
70,898
54,338
53,830
44,269
33,039
253,016
816,562
Thousand
short tons
( 14,583)
( 25,184)
( 19,747)
( 21,894)
( 93,613)
( 89,579)
( 73,701)
( 78,165)
( 59,908)
( 59,348)
( 48,807)
( 36,425)
(278,950)
900,260
Percent
of
total
1.6
2.8
2.2
2.4
10.4
9.9
8.2
8.7
6.6
6.6
5.4
4.0
31.0
100.0
Minerals Yearbook, 1976. Bureau of Mines.
-------
less than 22,676 Mg (25,000 tons) to several million mega-
grams (tons) per year. Of the 5214 quarries worked in 1976,
those with an annual production of less than 22,676 Mg
(25,000 tons) represented 38.9 percent of the total number,
yet accounted for only 1.6 percent of total production.
Quarries with an annual production of 816,326 Mg (900,000
tons) and over, on the other hand, accounted for 31 percent
of production, but represented only 3.2 percent of the
number of quarries.
Rock mined in these quarries is reduced to stone and
graded into products in a stone-crushing plant. Plant
capacities may range from less than a hundred to several
thousand megagrams (tons) per hour. Acpording to unpublished
data for 1973 from the Bureau of Mines, 1785 quarries were
reportedly serviced by stationary plants, 1533 by portable
2
plants, and 112 by both. A total of 781 quarries reported
having no stone-crushing plants, leaving about 600 quarries
unaccounted for.
4.1.1 Rock Types and Distribution
Major rock types processed by the industry include
limestone and dolomite, which accounted for 73.2 percent of
the total tonnage in 1973 and have the widest and most
important applications; granite (11.4 percent); trap rock
(7.9 percent); and sandstone, quartz, and quartzite (2.9
4-3
-------
percent). Rock types including calcareous marl, marble,
shell, slate and miscellaneous others accounted for only 4.6
percent. Nomenclature used by the industry varies con-
siderably and in many cases does not reflect actual geo-
logical definitions.
Limestone and dolomite are sedimentary rocks formed by
the deposition of animal and plant remains. In its pure
state, limestone consists of crystalline or granular calcium
carbonate (calcite); dolomite is calcium-magnesium carbo-
nate. They are often found together in the same rock
deposit. Depending on the proportions of the constituents,
rock may be classified as limestone, dolomitic limestone,
lime dolomite, or dolomite. Deposits are common and are
distributed throughout most parts of the country. The major
ones, however, are in the Central, Middle Atlantic, and
South Atlantic regions, which contributed more than 93
percent of the total production in 1973.
The industry regards any light-colored, coarse-grained
igneous rock as "granite." It is composed chiefly of quartz
(SiO2), feldspar, and, usually, mica. Deposits are found in
the South Atlantic, Northeastern, North Central, and Western
regions of the country. The South Atlantic region accounted
for more than 77 percent of the total tonnage of granite
produced in 1973.
4-4
-------
Trap rock is any dark colored, fine-grained igneous
rock composed of the ferro-magnesian minerals and basic
feldspars and containing little or no quartz. Common
varieties include basalts, diabases, and gabbros. Deposits
are mostly found in the New England, Middle Atlantic, and
Pacific regions, which combined accounted for 76 percent of
all trap rock produced in 1973.
Sandstones and quartzitic rocks are scattered through-
out the country. Sandstones are sedimentary rocks composed
predominantly of cemented quartz grains. The cementing
material may be calcium carbonate, iron oxide, or clay.
Quartzites are siliceous cemented sandstones. All regions
accounted for some production, with the Pacific, West South
Central, and Middle Atlantic States combining for 60 percent
of the total.
4.1.2 Applications
Crushed and broken stone has many and diverse uses both
in its natural and processed state. The construction indus-
try consumes about 86 percent of the total output. This
breaks down to the following applications: dense graded
road base stone, 24.4 percent of the total; concrete aggre-
gate, 14.5 percent; unspecified construction aggregate and
roadstone, 12.4 percent; cement manufacture, 10.9 percent;
bituminous aggregate, 9.7 percent; surface treatment aggre-
gate, 5.4 percent; and macadam aggregate, 3.3 percent.
4-5
-------
These materials are also used in lime manufacture, 3.6
percent; agriculture, 3.2 percent; metallurgical flux, 2.7
percent; riprap and jetty stone, 2.6 percent, and railroad
ballast, 1.7 percent. Remaining miscellaneous uses account
for only about 5.6 percent of total production.
4.1.3 Demand for Crushed Stone
The long-term rate of growth (1963 through 1972) in the
crushed stone industry has been at an annual rate of 3.3
percent. This will probably change over the remainder of
the decade and through 1985 partly because the rate of
construction expenditure is expected to decline from 2.1
percent to no more than 2.0 percent from 1972 to 1980 and also
because the industry has reached stability with respect to
product substitution. Thus, anticipated crushed-stone
consumption should grow at about 3 percent per year, com-
pounded from 1974 to 1985 on a tonnage basis. The use of
both limestone and granite is expected to increase in re-
gard to their current proportion of total crushed-stone
consumption. The use of these minerals is expected to grow
at slightly faster rates than average. Little or no growth
is anticipated in the consumption of trap rock or sandstone,
and the use of miscellaneous stone types should continue to
decrease in total tonnage.
4-6
-------
4.1.4 Distribution
Crushed stone is distributed directly from the quarry
to the user with no intermediary involved. It is readily
available in most metropolitan areas because transportation
and distribution are predominantly by truck. Inventories
are held almost entirely at the quarry location because
double handling would be prohibitively expensive, and cus-
tomers maintain only sufficient inventory to insure uniform
production rates over a predetermined time. Crushed-stone
production and shipments are seasonal in many northern
regions. Northern producers will typically operate their
plants for 9 months a year and stockpile sufficient stone to
cover a greatly reduced demand during the winter.
4.1.5 Plant and Firm Economics
Process Economics—
Two main types of plants are used, stationary and
portable. The latter is merely a standard stationary plant
mounted on a rubber-tired chassis, but it sometimes has an
advantage over the stationary model. The portable plant is
more useful to:
0 highway contractors who supply their own con-
struction materials at or close to the site,
0 independent operators who move their equipment
from quarry to quarry and prepare sufficient
material to supply a rural county or township for
a certain period,
0 local public authorities.
4-7
-------
More often than not, cost differentials between portable and
stationary plants are dwarfed by the differentials between
stone types processed.
The free on board (FOB) value of hard crushed stones,
granite, trap rock, sandstone, and quartzite, for example,
is higher than for soft stones such as limestone, dolomite,
and marl. The higher costs of quarrying and crushing ex-
plain, in part, the FOB value differential.
Firm Characteristics—
The Bureau of the Census does not compile statistics on
patterns of ownership in the mining industries, as it does
in the manufacturing industries. It is difficult, therefore,
to characterize the crushed-stone industry precisely in
regard to the types of firms involved. It is possible,
however, to make certain generalizations based on industry
contacts and the past experience of an EPA consultant.
The crushed-stone industry consists of a large number
of small, locally owned firms which account for a minor
proportion of national production, and a small number of
larger firms which are regionally or nationally diversified
and account for a large percentage of overall production.
The relationships of quarries by size, as shown in Table
4-1, provide a reasonable description of the relative
distribution of firms in the industry.
4-8
-------
Patterns of firm ownership are similar to those in
other sectors of the construction-oriented basic materials
industry. Types range from small, local companies in which
the plant manager and the owner are often the same person to
plants owned by diversified major firms. Many of these
larger firms also operate captive quarries to supply their
other manufacturing businesses such as steel mills, lime
plants, and cement mills. Between the two extremes are
firms that are less diversified in terms of geography and
business, yet which can compete effectively with the larger
firms on a regional basis.
Financial Resources—
Table 4-2 depicts the financial profile of a typical
crushed-stone plant. The following points from this table
are worth noting:
0 The industry operates on an average rate of prof-
itability for all U.S. firms. Net profit margins
are 7 percent; returns on shareholders' equity 11
percent.
0 The industry is capital intensive and moderately
leveraged. Debt represents 1/3 of total capital-
ization.
0 Depreciation and depletion represent major sources
of funds for capital expansion.
0 A major portion of the industry's assets is tied-
up in working capital, primarily inventories and
accounts receivable.
It should be stressed that Table 4-2 is a typical
statement, a synthesis of information from the Department of
4-9
-------
Table 4-2. TYPICAL CRUSHED-STONE PLANT FINANCIAL STATEMENTS'
(Index: Revenues = 100)
BALANCE SHEET
Current assets 60
Fixed assets
Land 8
Plant and equipment 110
Accumulated deprecia-
tion (55)
Miscellaneous assets 3
Current liabilities
Long-term debt
Equity
30
32
64
Total assets
126
Total liabilities
126
Income statement
Source and application of funds
Revenues 100
Production costs
Direct labor (19)
Materials (20)
Repair and maintenance (19)
Gross margin
Fixed costs
SG&A
Depreciation
Depletion
Interest
Profit before taxes
Taxes
Net profit
42
(14)
(10)
(4)
12
(5)
Sources
Net income
Depreciation
Depletion
Increase in long-term debt
Application
Capital expenditures
Land purchase
Increase in working
capital
Dividends
7
10
2
3
22
16
2
3
1
22
4-10
-------
Commerce and the Bureau of Mines together with that obtained
during an earlier study. These figures may vary signifi-
cantly for individual plants according to such parameters as
the following:
° Plant size. Larger plants enjoy economies of
scale that enable them to increase labor utiliza-
tion. Labor as a percentage of revenues may be
reduced by 30-40 percent (to 12-15% of revenues)
in modern plants in the 909-Mg/h (1000-tons/h)
category.
° Plant age. Newer plants have proportionately
larger depreciation charges, offset by smaller
expenses for repairs and maintenance. With higher
investment bases, newer plants have lower returns
on net assets and shareholders' equity.
0 Plant location. Costs differ between plants in
different locations based on the supply and demand
relationships for labor and materials. In the
Northeast, for example, the cost of materials
(e.g., fuel) and labor is higher, relative to
other costs, than in the South. In addition, the
market environment in which a plant operates will
determine the attainable revenue for each plant.
Plants that are favorably located relative to
their competition will realize greater profit
margins.
4.1.6 Current Prices
In April 1977, quotations in Engineering News Record
for carload lots of 3.8-cm (1-1/2-in.) crushed stone ranged
from $8.10 per Mg ($7.35 per ton) in Minneapolis to $1.98
($1.80) in St. Louis. These prices are based on an FOB city
basis and are summarized in Table 4-3. The average price of
3.8-cm (1-1/2-in.) stone for the 18 cities shown in the
4-11
-------
Table 4-3. CRUSHED-STONE PRICES FOB CITY
Region/city
Price range as of April 1977,
$ per Mga
3.8-cm stone
(1-1/2-in. stone)
1.9-cm stone
(3/4-in. stone)
NEW ENGLAND
Boston
MIDDLE ATLANTIC
New York
Philadelphia
Pittsburgh
EAST NORTH CENTRAL
Chicago
Cincinnati
Cleveland
Detroit
WEST NORTH CENTRAL
Kansas City
Minneapolis
St. Louis
SOUTH ATLANTIC
Atlanta
Baltimore
EAST SOUTH CENTRAL
Birmingham
WEST SOUTH CENTRAL
Dallas
PACIFIC
Los Angeles
San Francisco
Seattle
3.91
6.33
4.57
7.81
2.48
3.19
5.59
3.41
3.80
8.09
1.98
4.68
3.47
2.09
5.73
4.97
7.81
7.43
4.13
6.33
4.57
8.03
2.92
3.19
5.59
3.52
3.80
8.09
1.98
5.01
3.58
2.09
6.01
4.97
6.82
7.43
a $ per ton 0.91-$ per Mg.
4-12
-------
table is $4.85 per Mg ($4.41 per ton). For 1.9-cm (3/4-in.)
crushed stone, the average is $4.89 per Mg ($4.45 per ton).
These price quotations include transportation costs
that might range from $0.55 to $1.65 per Mg ($0.50 to $1.50
per ton) from quarry to city.
4.2 COST OF CONTROLLING PROCESS SOURCES
Control methods generally applied to process-generated
emissions include dry collection, wet dust suppression, and
a combination of the two. Dry collection involves hooding
or enclosing dust-producing points and exhausting emissions
to a collection device. Wet dust suppression consists of
introducing moisture into the material flow to prevent fine
particulate matter from becoming airborne. Combination
systems apply both methods at different stages throughout
the process.
4.2.1 Cost Estimation
Capital investment and annual costs for retrofitting
existing plants with each of the control systems are pre-
sented under separate headings. Table 4-4 lists cost ele-
ments of total capital investment. Investment for a partic-
ular case can be estimated by adding up costs of applicable
elements. Annual costs were estimated by adding up items
listed in Table 4-5. For comprehensive presentation,
4-13
-------
Table 4-4. ESTIMATION OF CAPITAL INVESTMENT
FOR CONTROL DEVICES
Component
Equipment
Ductwork
Stack
Instrumentation
Electrical
Foundations
Structural
Sitework
Painting
Piping
Total direct costs
Direct costs
Material
Labor
Component
Engineering
Contractor's fee
Shakedown
Spares
Freight
Taxes
Total indirect costs
Indirect costs
Measure of costs
10% material and labor
15% material and labor
5% material and labor
1% material
3% material
3% material
Contingencies - 10% of direct and indirect
Total fixed capital
Working capital
Total investment
Costs
4-14
-------
Table 4-5. CALCULATION OF ANNUALIZED COSTS
OF AIR POLLUTION CONTROL SYSTEMS
Cost component
I
M
in
Direct operating costs
Utilities
Water
Electricity
Operating labor
Direct
Supervision
Maintenance and supplies
Labor and material
Supplies
Fixed costs or indirect charges
Overhead
Plant
Payroll
Capital charges
Capital recovery
Insurance and taxes
Method of calculation
Amount used per year x $0.0625/m ($0.25/1000 gal)
Amount used per year x 0.04/kWh
Number of man-hours per x $5.00 to $6.50/h
15% of direct labor
3 to 10% of fixed capital investment
15% of labor and material
50% of rated operating labor plus 50% of maintenance
and supplies or 3% of fixed capital investment
20% of operating labor
13.2% of fixed capital investment'
2% of fixed capital investment
Based on a 15-year loan at 10 percent interest.
-------
several cost items are often lumped together. For example,
lump sum labor cost may include costs for direct labor,
supervision, payroll overhead, and plant overhead. Fixed
charges account for depreciation, interest, administrative
overheads, property taxes, and insurance. Depreciation and
interest are computed by means of a capital recovery factor
(CRF), the value of which depends on the operating life of
the control device and on the interest rate. Unless stated
otherwise, an operating life of 15 years and an annual
interest rate of 10 percent are assumed. Three sizes of
plants were considered: a 182-Mg/h (200-tons/h) portable
unit, and a 273-Mg/h and a 545-Mg/h (300- and 600-tons/h)
stationary plant.
The cost per unit of pollutant removed, i.e., cost-
effectiveness, is computed for the dry collection system.
Because estimates of emissions from plants controlled with
wet dust-suppression systems or combination control systems
are not available, cost-effectiveness cannot be computed.
4.2.2 Dry Collection Systems
The most commonly used dust collection device in the
crushed-stone industry is the fabric filter, or baghouse.
Capital investment of fabric filter systems for the three
model plant sizes were obtained from cost data in Reference
4. The costs are based on the following general specifica-
tions:
4-16
-------
0 Polypropylene felt bags are used;
0 Fabric filter housings are constructed of carbon
steel;
0 Collection efficiency is 99.8 percent;
0 The collector operates at negative pressure with
the fan located at the outlet side of the filter;
0 Bags are cleaned by air pulse jet.
Based on generalized exhaust gas volume data, Figure
4-1 shows exhaust gas volumes of fabric filter systems in
plants of various sizes. Tables 4-6 and 4-7 present capital
investment and annual costs, respectively, of the three
fabric filter systems. Costs of necessary hooding and
enclosures and ductwork are included. The 182-Mg/h and
273-Mg/h (200- and 300-tons/h) plants have two baghouses,
and the 545-Mg/h (600-tons/h) plant has three. Figure 4-2
shows the variation of cost effectiveness with plant
capacity.
4.2.3 Wet Dust-Suppression System
In a wet dust-suppression system, dust emissions are
controlled by applying moisture to the crushed material at
critical dust-producing points in the process flow as shown
in Figure 3-1. This causes dust particles to adhere to
large stone surfaces or to form agglomerates too heavy to
become or to remain airborne.
4-17
-------
u
00
a:
10*
9
8
7
6
10*
102
102
I
I I I
2 3 45678
PLANT CAPACITY, Mg/h
I
I I I
60
50
40
30
20
15
10
8
2 3 4 5 6 7 8 9 103
PLANT CAPACITY, tons/h
o
u.
Figure 4-1. Exhaust gas volumes at various plant capacities'
4-18
-------
Table 4-6. CAPITAL INVESTMENT OF FABRIC FILTER SYSTEMS
Process parameter
Exhaust gas rate,3 m /s
(acfm)
2
Filter area at 6.5 A/C, m
(ft2)
No. of filters (baghouses)
Fixed capital investment
182 Mg/h
(200 tons/h)
15.5
(33,000)
470
(5,100)
2
$144,800b
Plant size
273 Mg/h
(300 tons/h)
26.7
(48,000)
690
(7,400)
2
$202,000b
545 Mg/h
(600 tons/h)
38.7
(82,000)
1,180
(12,600)
3
$339,800b
See Figure 4-1.
From Reference 4. Data in Reference 4 are based on data in
Reference 5.
4-19
-------
Table 4-7. ANNUAL COSTS OF FABRIC FILTER SYSTEMS3
(2200 operating hours per year @ 75 percent of rated capacity)
(Costs for December 1976)
Items
Electric power (103, 144, 260}
(hp) (0.75 kW/hp) (1650 h/yr)
($0.04/kWh)
Maintenance labor (4, 6, 10 h/wk)
(h/wk) ($5.50/h) (52 wk/yr)
Maintenance material
Operation labor (1,2,3 h/wk)
(h/wk) ($5.50/h) (52 wk/yr)
Supplies c
Bags (416,605.1034)
($4.31/m2) (m2)/2
(Bags) (0.1 man-hour/bag) ($5.50/h;
Payroll overhead (35% of labor)
Indirects (40% of maintenance
and supplies)
Insurance and local taxes
(2% of fixed capital)
Capital recovery
(13.2% of fixed capital)
Total Costs
Annual tonnage, Mg
(ton)
Unit cost, C/Mg
(C/ton)
Cost-effectiveness
C/kg pollutant removed
(C/lb pollutant removed)
182 Mg/h
(200 tons/h)
$10,450b
1,140
3,520
220
1,020
110
500
2,320
2,900
18,820
$ 41,000
299,300
(330,000)
13.7
(12.5)
2.5
(1.2)
273 Mg/h
(300 tons/h)
$7,130
1,720
4,720
560
1,480
170
800
3,230
4,040
26,260
$ 50,110
449,000
(495,000)
11.2
(10.1)
2.0
(0.9)
545 Mg/h
(600 tons/h)
$12,870
2,860
7,920
840
2,520
300
1,300
5,440
6,800
44,170
$ 85,020
898,000
(999,000)
9.5
(8.5)
1.7
(0.7)
From Reference 4.
Diesel power assumed for 200-ton portable plant (equivalent cost
8.2^/JcWh) .
c Based on 2-year bag life and filter are as in Table 4-6.
Based on uncontrolled emissions of 5.5 kg/Mg (11.0 Ib/ton).
4-20
-------
o
UJ
UJ
cc
o
QL.
u. 2
t/)
UJ
o
UJ
100 200 300 400 500
PLANT CAPACITY, Mg/h
600
700
800
Figure 4-2. Cost-effectiveness of fabric filter
(dry collection) systems.
4-21
-------
Table 4-8 presents capital investment of wet dust-
suppression systems. The systems include the following
auxiliary items:
0 Shelter house for pump metering mechanism,
0 Water filter and flush system,
0 System winterization,
0 Automatic spray at truck dump station.
Annual costs are presented in Table 4-9.
4.2.4 Combination Systems
Wet dust-suppression and dry collection techniques are
often used in combination to control particulate emissions
from crushed-stone facilities. As illustrated in Figure
3-5, wet dust-suppression techniques are generally used to
control emissions at the primary crushing stage and at
subsequent screens, transfer points, and crusher feeds. Dry
collection is generally used to control emissions at second-
ary and tertiary crusher discharges, where new dry stone
surfaces and fine particles are formed. A large portion of
the fine particulates is removed by dry collection, but
subsequent dust-suppression applications become more effec-
tive with a minimum of added moisture. Depending on pro-
duction requirements, dry collection may be the only method
that can be used at the finishing screens.
4-22
-------
Table 4-8. CAPITAL INVESTMENT OF WET DUST-SUPPRESSION SYSTEMS'
(Costs for December 1976)
Items
Dust-suppression equipment
Auxiliary equipment
Water filter and flush
High pressure truck dump station
Shelter house
Equipment winterization
Auxiliary equipment total
Total equipment cost
Installation costs - direct
Foundation and supports
Piping
Insulation
Painting
Electrical
Total direct installation costs
Installation costs - indirect
Engineering
Construction and field expense
Construction fees
Start-up
Performance
Contingencies
Total indirect installation costs
Fixed capital investment
Plant size
182 Mg/h
(200 tons/h)
$10,050
2,280
5,490
2,170
2,660
$12,600
$22,650
860
17,500
4,780
None
13,160
$36,300
1,900
1,390
360
1,710
370
1,820
$ 7,550
$66,500
273 Mg/h
(300 tons/h)
$11,610
2,280
5,760
2,170
2,880
$13,090
$24,700
860
18,240
5,160
None
13,190
$36,450
2,030
1,500
360
1,710
380
1,870
$ 7,850
$70,000
454 Mg/h
(600 tons/h)
$15,060
2,280
4,210
2,170
3,080
$11,740
$26,800
860
19,970
5,860
None
13,730
$40,420
2,140
1,710
360
1,710
400
2,020
$ 8,340
$75,560
a Cost data for the 182-Mg/h (200-tons/h) plant are estimated from data
in Reference 5; data for the remaining two plants are from Reference
4-23
-------
Table 4-9. ANNUAL COSTS OF WET DUST-SUPPRESSION SYSTEMS9
(2200 operating hours per year @ 75 percent of rated capacity)
(Costs for December 1976)
Cost item
Operating labor
Operator
Supervisor
Subtotal
Maintenance
Labor
Materials
Subtotal
Replacement parts
Utilities
Electricity
WaterC •
Subtotal
Wetting agent
Total direct costs
Fixed charges
Overhead
Insurance and local
taxes
Capital recovery
Total fixed charges
Total annualized cost
Annual output, Mg
(ton)
Unit cost, c/Mg
K/toni
Unit cost
or basis
S5.50/h
S7.00/h
$6.00/h
$0.04/kWh
$0.066/m3
$880/m3
Plant size
182 Mg/h j
200 tons/h!
$360
120
$480
$240
670
$910
$460
$ 75
60
$135
$600
$2,785
20% of labor
+50% of labor! 790
4 maintenance
2% of fixed
capital
$1,330
13.2% of fixed 6,640
capital
$10,760
$13,545
299,300
(330,000)
4.5
(4.1)
273 Mg/h
(300 tons/h
$360
120
$460
$290
1.000
$1,290
$ 460
$100
90
$190
$1,200
$3,620
980
$1,400
9,100
$11,480
$15,100
449,000
(495,000)
3.3
(3.0)
545 Mg/h
(600 tons/h)
$360
120
$480
$430
1,500
$1,930
$ 460
$250
180
$430
$2,410
$5,710
1,300
$1,510
9,820
$12,630
$18,340
698,000
(990,000)
2.0
(1.8)
From Reference 4.
System operation is automatic. The only labor required on a
daily basis is that needed to start the system.
c
Computed on basis that wetting agent treatment is required
only 40 percent of operation time becuase of initial moisture
d content of the material and prevailing weather conditions.
Assumes high volume purchase of wetting aoent. i.e., greater than
2.27 m3 (600 gal) per order.
4-24
-------
Tables 4-10 and 4-11 present capital investment and
annual costs, respectively, of the model combination control
systems.
4.3 COST OF CONTROLLING FUGITIVE DUST SOURCES
Table 2-1 categorizes all emission sources associated
with crushed-stone production as either process or fugitive.
Fugitive dust sources include blasting, loading and hauling,
open conveyors, and storage piles. Emissions are caused by
load-in, load-out, and wind. This section presents the cost
of controlling these fugitive dust sources. Because esti-
mates of emissions from fugitive dust sources are not
available, cost-effectiveness cannot be computed.
4.3.1 Blasting
No method is known for effectively controlling particu-
late emissions from blasting operations. As discussed in
Section 3.1.2, the impact of blasting may be reduced by
employing good blasting practices.
4.3.2 Loading and Hauling
As discussed in Chapter 2, no effective method is known
for suppressing or capturing emissions from loading. Water-
ing the material in the trucks after they have been loaded
will reduce emissions from the trucks during hauling.
Several methods available for reducing or controlling
4-25
-------
Table 4-10. CAPITAL INVESTMENT OF COMBINATION SYSTEMS
(Fabric filter and wet dust suppression)
Process parameter
Exhaust gas
rate for fabric ^
filter system, m /s
(acfm)
Filter area at 6.5
A/C, m2
(ft: )
No. of filters
(baghouses)
Capital investment
Fabric filter
Wet dust-suppression
system
Total fixed capital
investment
182 Mg/h
(200 tons/h)
5.2a
(11,000)
160
1,700)
1
72,000°
d
59,000
131,000
Plant size
273 Mg/h
(300 tons/h)
7.8b
(16,500)
240
2,540)
1
92,000°
d
63,000
151,000
545 Mg/h
(600 tons/h)
11. 8b
(25,000)
360
(3,850)
1
120,000°
d
68,000
188,000
a Estimate based on data in Reference 6.
Reference 6.
c Based on data in Reference 5.
Based on data in Reference 5; these costs are estimated to
be 90 percent of the costs of wet dust-suppression systems
alone.
4-26
-------
Table 4-11. ANNUAL COSTS OF COMBINATION SYSTEMS
(Fabric filter and wet dust suppression)
(2200 operating hours per year @ 75 percent of rated capacity)
Direct costs for
dust-suppression system
Overhead for
dust-suppression system
Subtotal
Direct costs for
fabric filter system
Electric power (38, 51, 86)
(hp) (.75 kW/hp) (1650 h/yr)
(5.04/kWh)
Maintenance labor (4,4,4 h/wk)
(h/wk) (S5.50/K) (52 wk/yr)
Maintenance material
Operation labor (1,1,1 h/wk)
(h/wk) <$5.50/h (52 wk/yr)
Supplies
Bags (139, 208, 315)
($4.31 m2) (m2/2)
(Bags) (0.1 man-hours) ($5. 50/h)
Overhead for fabric filter system
Payroll overhead (35% of labor)
Indirects (40% of maintenance
and supplies)
Subtotal
Insurance and local taxes
(2% of fixed capital)
Capital recovery
(13.2% of fixed capital)
Total annual costs
Annual tonnage, Mg
(ton)
Unit cost, C/Mg
(C/ton)
Plant sise
182 Mg/h
(2*0 tons/h)
S 2,900*
790*
3,690
3,860b
1,140
1,200
220
340
40
480
1,090
8,370
2,620
17,030
$31,710 «
273 Mg/h
300 tons/h)
$3,750*
980*
4,730
3,520
1,140
1,500
220
510
60
480
1,280
8,710
3,100
20,150
136,690
299,200 449,000
330,000) (495,000)
10.6
(9.6)
8.1
(7.4)
545 Mg/h
600 tons/h)
$5.810*
1,300*
7,110
4,260
1,140
2,000
220
770
90
480
1,600
10,560
3,760
24,440
$45.870
898,000
990,000)
S.I
(4.6)
From Table 4-8.
b
Diesel power assumed for 182-Mg/h (200-tons/h) portable plant
(equivalent cost 8.2«/kKh).
c Based on 2-year bag life and filter areas in Table 4-10.
4-27
-------
emissions from trucks traveling on unpaved roads include
watering, oiling, paving, and limiting vehicle weight and
reducing vehicle speed. Sweeping or vacuuming reduces
emissions on paved roads.
Published truck speed data are not available, but the
industry estimates that the speed ranges from 10 to 20 mph.
If this speed were reduced from an average of 15 to an
average of 10 mph, this would produce an estimated emission
Q
reduction of 65 percent. More vehicles would be required
to maintain production, but particulate emission reduction
would still remain at 65 percent because there would be no
increase in mileage. The estimated costs of this emission
reduction method for the model plants are shown in Table
4-12. The costs are based on an estimated requirement of
one additional 31.8-Mg (35-ton) truck for the 182-Mg/h
(200-tons/h) and 273-Mg/h (300-tons/h) plants and two trucks
for the 545-Mg/h (600-tons/h) plant. Table 4-12a presents
unit cost data for controlling fugitive dust emissions from
plant roads.
Table 4-12 also presents capital investment and annual
costs of paving, sweeping or vacuuming paved roads, oiling,
and watering. These costs depend on the extent of plant
roads, which usually do not vary significantly with plant
capacity. Consequently, the control cost per ton of crushed
4-28
-------
Table 4-12. CAPITAL INVESTMENT AND ANNUAL COSTS FOR
CONTROLLING FUGITIVE DUST EMISSIONS FROM
CRUSHED-STONE PLANT ROADS
Item
Capital investment, $
Paving
Vacuuming
Oiling (annual costs)
Watering
Speed reduction
Annual Costs, $
Paving
Vacuuming
Oiling
Watering
Speed reduction
Annual costs, £/Mg
Paving
Vacuuming
Oiling
Watering
Speed reduction
Plant size
182 Mg/h
(200 tons/h)
28,000
22,000
30,000
14,000
150,000
8,400
11,400
30,000
31,300
87,500
2.8
3.9
10.0
10.5
32.2
283 Mg/h
(200 tons/h)
28,000
22,000
30,000
14,000
150,000
8,400
11,400
30,000
31,300
87,500
1.9
2.5
6.6
6.9
19.5
545 Mg/h
(600 tons/h)
28,000
22,000
30,000
14,000
300,000
8,400
11,400
30,000
31,300
175,000
0.9
1.3
3.3
3.5
19.5
Based on two 31.8-Mg (35-ton) trucks for the 182-Mg/h (200-
tons/h) and 273-Mg/h (300-tons/h) plants and two trucks for
the 545-Mg/h (600-tons/h) plant.
C/ton = 0.91 x $/Mg.
4-29
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Table 4-12a.
UNIT COSTS FOR CONTROLLING FUGITIVE DUST EMISSIONS
FROM CRUSHED-STONE PLANT ROADS
I
U)
o
Control
measure
Paving
Vacuuming
Oiling
Watering
Speed ,
reduction
Capital cost
unit
1.7 km, 3.65 m wide
(1 mile, 12 ft wide)
one sweeper
1.7 kg, 365 m wide
(1 mile, 12 ft wide)
Truck equipped with
a 1.1-kl (3000-gal)
tank
One 31.8-Mg (35-ton)
truck
$/unit
28,000b
22,000b
5,000b
12,000 to
16,000d
150,000
Annual
cost, $/yr
8,400
11,400C
30,000
31,300e
87,5009
Comment
Repave every 5 years
Vacuuming twice a week
Reoil every month
Watering the roads four to five
times a day
Estimated truck life of
5 years
The cost of capital (interest) assumed at 10 percent.
From Reference 9.
C Assumed vacuum life of 5 years; maintenance at 3 percent of capital cost; labor at
8 hours per week, $9.25 per hour including overhead.
From References 10 and 11.
e See Table 4-13.
Estimated.
g Includes wages of truck driver at $12 per hour, including overhead.
-------
stone will be higher than the average for smaller plants.
The length of unpaved roads in a typical crushed-stone plant
is estimated to be 0.63 km (1 mile). Table 4-13 presents a
breakdown of the annual cost of watering. The costs are
based on a watering frequency of four to five times a day.
4.3.3 Conveyors
Emissions from conveyor transfer points are considered
to be process emissions, whereas those due to wind are
regarded as fugitive. The latter can be controlled or
suppressed by installing covers over the conveyors or water
sprayers along their length. If the material being conveyed
is sprayed at the conveyor inlet (which may be a crusher/
screen outlet or transfer point), the suppression effect is
usually carried over; hence, installation of additional
sprayers may only marginally increase the suppression
efficiency. For this reason, costs of installing sprayers
are not estimated here. Costs of retrofitting covers on
existing conveyors may range from $35 to $70 per foot of
conveyor length, depending on the amount of work required
12 13
and the type of covering. ' The lower figure applies to
a "weather-tight" system, which protects the conveyed mate-
rial from direct winds and precipitation. A "dust-tight"
system, which is usually vented to a bag filter, costs twice
as much. Total conveyor lengths for crushed-stone plants
4-31
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Table 4-13. ANNUAL COST OF WATERING
CRUSHED-STONE PLANT ROADWAYS
Cost item
Quantity
Unit cost
Cost/year
Operating costs
Water 136 m /day $0.063/m
(36,000 gal/day) ($0.25/1000 gal)
9.5 liters/day $0.13/liter
(2.5 gal/day) ($0.50/gal)
2,000 h
5% of initial tank-truck cost
12.00 /man-hour
c
Fuel
Labor
Maintenance
Fixed charges
Capital 26.4% of initial tank-truck costc
recovery
Insurance 2% of initial tank-truck cost0
and taxes
Total annual cost
Cost per ton for a 182-Mg/h (200-tons/h) plant6
Cost per ton for a 273-Mg/h (300-tons/h) plant6
Cost per ton for a 545-Mg/h (600-tons/h) plant6
$ 2,300
300
24,000
700
3,700
300
$31,300
10.5$/Mg
6.9C/Mg
3.5
-------
vary significantly, ranging from a few hundred to a few
thousand feet. Because maintenance costs of conveyor covers
are minimal, the annual cost will depend mainly on the
remaining plant life and the cost of capital (interest).
4.3.4 Storage Piles
Fugitive emissions from storage piles are due to load-
in, wind erosion, and load-out.
Materials at crushed-stone plants are usually taken to
storage piles via a conveyor system. Emissions result
mainly from the free fall of material onto the pile. As
discussed in Chapter 3, control measures include wet dust
suppression, telescopic chutes, stone ladders, and movable
stacking conveyors. Enclosures or silos are very good for
controlling load-in and windblown emissions; however, they
are not considered economically practical control measures
for crushed-stone plants. Table 4-14 presents capital
investment costs of stone ladders, telescoping chutes,
movable stackers, and enclosures. Because this equipment
requires very little maintenance, the annual cost will
depend mainly on the remaining plant life and the cost of
capital (interest).
Spraying storage piles with water effectively reduces
fugitive emissions from wind erosion, and the addition of
dust-suppressant chemicals to the spray increases control
4-33
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Table 4-14. CAPITAL INVESTMENT FOR REDUCING FUGITIVE
DUST EMISSIONS FROM STORAGE PILES
Control
measure
Fixed capital investment
Unit
Stone ladder
Telescoping chutes
Movable stacker
Enclosures
9.1-m (30-ft) pile
Chute
0.907 Mg (ton) per hour
throughput
0.76 m3 (yd3)
20,000a
26,000-42,OOO1
700a
80-200b
Reference 14
Reference 15,
4-34
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efficiency. The truck that waters plant roads can be
equipped with a hose for spraying storage piles. Alterna-
tively, an elevated sprinkler system may be used to spray
the stock piles. The cost of elevated sprinkler systems
ranges from a few thousand dollars to $20,000, depending on
the plant. If the sprinkler pump could be accommodated in
an existing pump house, for example, this would save the
cost of a new pump house. Costs of spraying storage piles
with a wetting agent are estimated to range from $0.01 to
17 18
$0.06 ' per Mg ($0.05/ton) of product, depending on the
type of chemical used, the number of storage piles, and the
frequency of spraying. The latter depends on climate and
operational activities around the pile.
Crushed stone is usually loaded into trucks by front-
end loaders. As discussed in Section 4.3.2, there is as yet
no acceptable way of suppressing or capturing the load-out
emissions. Watering the material in trucks after they have
been loaded will reduce emissions during hauling.
4-35
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REFERENCES FOR CHAPTER 4
1. Mineral Commodity Summaries, 1978. Bureau of Mines.
2. Bureau of Mines Data for 1973, unpublished.
3. The Crushed-Stone Industry: Economic Impact Analysis
of Alternative Air Emission Control Systems. Prepared
by Arthur D. Little, Inc., under Contract No. DU-AQ-76-
1349 for U.S. Environmental Protection Agency. Re-
search Triangle Park, North Carolina. Final Draft.
September 1975.
4. Letters to A. Kothari of PEDCo Environmental, Inc.,
Cincinnati, Ohio, from Richard E. Jenkins, Economic
Analysis Branch, Strategies and Air Standards Division,
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina. June 23 and July 1, 1977.
5. Nonmetallic Minerals Industries Control Equipment
Costs. Prepared by Industrial Gas Cleaning Institute,
Stamford, Connecticut for U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina, under
Contract No. 68-02-1473, Task No. 192. February 1977.
6. Evans, R.J. Methods and Costs of Dust Control in Stone
Crushing Operations. Bureau of Mines Information
Circular No. 8669. U.S. Dept of the Interior. 1975.
7. Private communication between A. Kothari of PEDCo
Environmental, Inc., Cincinnati, Ohio, and J. Houses of
General Crushed Stone, Easton, Pennsylvania. June 1,
1977-
8. Compilation of Air Pollutant Emission Factors. Second
edition with Supplements 1-5. U.S. Environmental
Protection Agency, Research Triangle Park, North
Carolina. Publication Number AP-42. February 1976.
p. 11. 2-4.
4-36
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9. Fugitive Emissions Control Technology for Iron and
Steel Plants (Draft). Prepared by Midwest Research
Institute, Kansas City, Missouri, for U.S. Environ-
mental Protection Agency, Research Triangle Park, North
Carolina, under Contract No. 68-02-2120. January 1977.
p. 29.
10. Private communication between B. Livingston of PEDCo
Environmental, Inc., Cincinnati, Ohio, and R. McCrate
of Reilly-Dven Co., Cincinnati, Ohio. May 13, 1977.
11. Private communication between B. Livingston of PEDCo
Environmental, Inc., Cincinnati, Ohio, and Interna-
tional Trucks, Cincinnati, Ohio. May 18, 1977.
12. Ref. 9. p. 33.
13. Private communication between A. Kothari of PEDCo
Environmental, Inc., Cincinnati, Ohio, and W. Van Eaton
of Armco Steel Corp., Metal Products Div., Cincinnati,
Ohio. May 1977.
14. Ref. 9. p. 33.
15. Technical Guidance for Control of Industrial Process
Fugitive Particulate Emissions. U.S. Environmental
Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, North Carolina.
Publication No. EPA-450/3-77-010, March 1977. pp. 2-39
and 2-40.
16. Automated Stockpile Sprinkling System. National
Crushed-Stone Association, 1415 Elliot Place, North-
west, Washington, D.C. 20007.
17. Ref. 9. p. 36.
18. Ref. 15. p. 2-40.
4-37
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5.0 ENVIRONMENTAL IMPACT OF APPLYING CONTROL TECHNOLOGY
This section presents an assessment of the incremental
impact to the environment associated with the application of the
emission reduction systems described in Chapter 3. Both bene-
ficial and adverse impacts are assessed on air, water, solid
waste, energy, and noise that may be directly or indirectly
attributed to the operation of these emissions control systems.
5.1 IMPACT ON AIR
Ideally, this section should present a comparative assessment
of impacts on air emissions associated with the application of
the alternative emission reduction systems (described in Chapter
3) for the control of particulate emissions from both process and
fugitive dust sources. Because emissions from fugitive dust
sources are typically large in area and are discharged directly
to the atmosphere in an unconstrained manner rather than through
a stack, such a quantitative measurement of these emissions would
be difficult, if not impossible. Consequently, few data are
available that permit the calculation of the emission reduction
achievable by the application of alternative control measures.
Similarly, because of the nature of wet dust suppression systems,
no data are available that permit a quantitative comparison of
5-1
-------
the control capabilities of wet dust suppression versus dry
collection systems on process sources. As a result, the following
discussion on air impact is necessarily limited to the application
of dry collection systems on crushed and broken stone process
facilities.
Table 5-1 presents estimates of the emission reduction
achievable by the application of dry controls on three model
plants reflecting typical production capacities of 182, 273, and
545 Mg/h (200, 300, and 600 tons/h). Estimates of uncontrolled
emissions presented are based on the uncontrolled emission factor
for process sources alone (reported in Subsection 2.1), which is
5.5 kg/Mg of capacity (11 Ib/ton). As indicated by the perform-
ance data presented in Section 3, the use of fabric filters to
collect particulate emissions at stone plants can easily achieve
an outlet concentration of 0.034 g/dry m (0.015 gr/dscf). If
adequate hooding and ventilation are also applied, essentially
complete capture is assured. The emission estimates with dry
controls were developed by assuming a 99 percent capture effi-
ciency and applying the fabric filter outlet concentration value
to the total ventilation requirements estimated for each model
plant. As shown in Table 5-1, uncontrolled emissions from the
182, 273, and 545 Mg/h plants were calculated to be 998, 1497,
and 2994 kg/h, respectively. The application of dry controls was
estimated to reduce emissions to about 12, 18 and 35 kg/h, which
corresponds to an overall emission reduction of about 98.8
percent.
5-2
-------
TABLE 5-1. ACHIEVABLE EMISSION REDUCTION USING DRY COLLECTION SYSTEM
Plant size,
Mg/h (tons/h)
Ventilation
size/
(scfm)
Emissions
Uncontrolled,
kg/h (lb/h)
Dry collection,
kg/h (lb/h)
Emission
reduction,
182 (200)
273 (300)
545 (600)
i
u>
15.3 (32,500)
22.3 (47,300)
38.0 (80,800)
998 (2,200)
1,497 (3,300)
2,994 (6,600)
11.9 (26.2)
17.7 (39.1)
34.7 (76.4)
98.8
98.8
98.8
-------
5.2 IMPACT ON WATER POLLUTION
Dry collection control techniques generate no water effluent.
When wet dust-suppression techniques can be used, the water is
absorbed by the material processed so that wet dust-suppression
systems produce no water effluent either. No data are available
concerning the impact of dust-suppressants applied to roadways on
water quality. Considering the amount of suppressants required,
however, the use of suppressants should not cause any problem.
Thus, the application of air pollution control technology to the
crushed- and broken-stone industry has little impact on water
quality.
5.3 IMPACT ON SOLID WASTE DISPOSAL
The method of disposition of quarry, plant, and dust collec-
tor waste materials depends somewhat upon state and local govern-
ment and corporate policies. When fabric filter systems are
used, about 1.2 Mg (1-1/3 tons) of solid waste are collected for
2
every 227 Mg (250 tons) of rock processed. Often, this material
can be sold or used for a variety of purposes. Many plants sell
the collected fines from trap-rock, granite, limestone, etc., as
mineral filler for the manufacture of asphalt concrete. Many
companies operate both quarries and asphalt-concrete plants.
Depending on the chemical composition of the rock, some limestone
quarries sell the collected fines as agstone. Limestone screenings
and wastes are also an effective long-term neutralizing agent on
acidic spoils from mining operations. Such spoils generally
5-4
-------
continue to produce acidity as oxidation continues. The applica-
tion of limestone wastes produces alkalinity on a decreasing
scale for many years, after which a vegetative cover should be
well established.
Collected fines are normally disposed of in an isolated
location in the quarry if no market is available. A plant pro-
ducing 545 Mg/h (600 tons/h) and using dry collection for control
would generate about 22 Mg (24 tons) of waste over an 8-hour
period, which is less than 0.5 percent of the plant throughput.
Generally, the collected fines are discharged to a haul truck and
transported to the quarry for disposal. No subsequent air
pollution problems should develop, provided the waste pile is
controlled by one of the methods discussed in Chapter 3.
Thus, the solid waste generated by the application of dry
collection methods in the crushed-stone industry can be dispersed
of without any adverse impact on the environment. When wet dust
suppression is used, no solid-waste-disposal problem results over
that produced by normal operation.
5.4 IMPACT ON ENERGY CONSUMPTION
Application of the alternative control techniques for crushed
and broken stone production facilities will necessarily result in
an increase in energy consumption over that required to operate a
plant without air pollution controls. Table 5-2 presents esti-
mates of the energy requirements for three typical plants, both
with and without controls. The three model plants evaluated,
5-5
-------
which are identical to those used to determine the costs in
Chapter 4 and the impacts on air in Section 5.1, include a portable
plant with a capacity of 182 Mg/h (200 tons/h) and two stationary
plants with production capacities of 273 and 545 Mg/h (300 and
600 tons/h). As in the previous analyses, the alternative control
techniques evaluated include dry collection, wet dust suppression,
and the combination of dry and wet controls.
As might be expected, the application of dry collection
controls (fabric filters) results in the highest increase in
energy usage of the three alternative control techniques evaluated.
As indicated in Table 5-2, the energy required to operate a 545
Mg/h plant without controls is about 1038 kW (1392 hp). The
application of dry controls at this plant would require 194 kW
(260 hp) of additional energy to operate the fans, air compressors,
and screw conveyors associated with its application. This repre-
sents a 19 percent increase in energy consumption over that
required to operate the uncontrolled plant. At the 182 and 273
Mg/h plants, the application of dry controls would increase
energy requirements by 16 and 17 percent respectively.
In contrast, the energy requirement associated with the
application of wet dust suppression systems is negligible. For
the 545 Mg/h plant, the application of wet dust suppression
control would require only 3.8 kW (5 hp) of additional energy, or
less than a 0.4 percent increase in energy consumption. For the
two smaller model plants, the increase in energy consumption due
5-6
-------
TABLE 5-2.
ENERGY REQUIREMENTS FOR MODEL CRUSHED STONE PLANTS
[kilowatts (horsepower) ]
Plant size,
Mg/h (tons/h)
Uncontrolled
Dry collection
(Fabric filter)
Wet dust
suppression
Combination
wet and dry
182
273
545
(200)
(300)
(600)
477 (640)
630 (845)
1038 (1392)
554 (743)
738 (989)
1232 (1652)
478.1 (641.5)
631.5 (847)
1041.3 (1397)
495 (663)
668 (896)
1100 (1478)
Extrapolated from data in Reference 4.
Reference 4.
-------
to wet dust suppression controls is about 0.2 percent. If a
combination of both wet and dry controls were applied to each of
the three model plants, the additional energy requirements would
be 18, 38, and 62 kW (23, 51, and 86 hp), respectively, or about
6 percent.
5.5 IMPACT ON NOISE
Allowable noise levels and employee exposure times are
specified by the Mining Enforcement and Safety Administration in
Parts 55 and 56 of the August 7, 1974, Federal Register, Volume
39, No. 153. These limits require that potential noise problems
be assessed and sound-dampening equipment be installed as required
No noise data were developed during this study; however, compared
with the noise emanating from crushed-stone process equipment,
any additional noise from control system exhaust fans is likely
to be insignificant. Thus, no significant noise impact is antic-
ipated as a result of the use of best demonstrated control
technology at crushed-stone plants.
5-8
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REFERENCES FOR CHAPTER 5
1. Development Document for Interim Final Effluent Limitations
Guidelines and Standards of Performance - Mineral Mining and
Processing Industry - Volume I (Minerals for the Construction
Industry). Prepared by Versar, Incorporated, for the U.S.
Environmental Protection Agency, Washington, D.C.
EPA 440/1-75-/059. January 1975. p. V-3.
2. Source Testing Report - Essex Bituminous Concrete Corporation,
Dracut, Massachusetts. Prepared by Roy F. Weston, Incorpo-
rated, Westchester, Pennsylvania, for U.S. Environmental
Protection Agency. EPA Report No. 75 STN-2. December 27,
1974.
3. Development Document for Interim Final Effluent Limitation
Guidelines and New Source Performance Standards for the Coal
Mining Point Source Category. U.S. Environmental Protection
Agency, Washington, D.C. EPA 440/1-76/057-a. May 1976.
p. 85.
4. Standards Support and Environmental Impact Statement - An
1 Investigation of the Best Systems of Emission Reduction for
Qaurrying and Plant Process Facilities in the Crushed- and
Broken-Stone Industry. Draft Report. U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina.
August. August 1975.
5-9
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6.0 COMPLIANCE TEST METHODS AND MONITORING TECHNIQUES
6.1 EMISSION MEASUREMENT METHODS
EPA relies primarily on Methods 5 and 9 for particulate
matter measurements and visible emission observations (opacity)
on stacks. Both are established reference or compliance
methods and were used by EPA in obtaining the emissions data
presented in Appendix A on fabric filter collectors used in
the crushed-stone industry.
For fugitive emissions which are impractical to quantify,
EPA has relied historically on visual methods, specifically
on Method 9, to limit the opacity of visible emissions and
force the application of controls. In this study, a new method
in addition to Method 9 was used, Method 22. This draft method
(see Appendix B) was specifically developed by EPA for the
visual determination of fugitive emissions from material
processing sources. Rather than assess the opacity of a visible
emission, Method 22 determines the frequency at which a visible
emission occurs during an observation period. A standard can
thus be established which limits the percent of time during
which visible emissions from a fugitive emissions source would
be disallowed. Both methods were used in assessing the effective-
ness of local exhaust hoods and wet dust suppression in reducing
or preventing fugitive emissions from crushed-stone process
facilities. Method 22 appears to be more applicable to inter-
mittent sources of fugitive emissions while Method 9 is more
6-1
-------
applicable to continuous fugitive emission sources. In the
case of fugitive dust sources which are typically large in
area, EPA has no established procedures for either quantifying
emissions from -these sources or for assessing the visibility of
emissions from these sources.
During the test program on fabric filter collectors, it
was necessary to consider the potential problems associated with
low levels of controlled emissions from the sources. Data
from an EPA report indicate that particulate catches of about
50 mg are adequate to insure an error of no more than 10 percent.
Sampling trains with higher sampling rates, which are allowed
by Method 5 and are commercially available, can be used to
reduce the total sampling time and costs. Sampling costs of
a test consisting of three particulate runs (the number normally
specified by performance test regulations) is estimated to
be about $5000 to $7000. This estimate is based on sampling
site modifications such as ports, scaffolding, ladders, platforms
all costing less than $2000 and testing being conducted by
contractors.
Because the outlet gas stream from the control devices
used in this industry is generally well contained, no special
sampling problems are anticipated.
Procedures for monitoring the process are discussed in
Chapter 7.
6.2 MONITORING SYSTEMS AND DEVICES
The effluent streams from sources within the crushed-
6-2
-------
stone industry are essentially at ambient conditions.
Therefore, the visible-emission-monitoring instruments
proven adequate for power plants are also applicable for
this industry. These instruments are covered by EPA per-
formance standards contained in Appendix B of 40 CFR Part
60.
Equipment and installation costs are estimated to be
$6000 to $8000, and annual operating costs including data
2
recording and reduction, $8000 to $9000 for each stack.
6-3
-------
REFERENCES FOR CHAPTER 6
1. Mitchell, W.J. Additional Studies on Obtaining Repli-
cate Particulate Samples from Stationary Sources.
Unpublished report. Emission Monitoring and Support
Laboratory, Environmental Protection Agency, Research
Triangle Park, N. C., November 1973.
2. Standards Support and Environmental Impact Statement -
An Investigation of the Best Systems of Emission Re-
duction for Quarrying and Plant Process Facilities in
the Crushed- and Broken-Stone Industry. Draft Report, -
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina. August 1975.
6-4
-------
7.0 ENFORCEMENT ASPECTS
When formulating an air pollution control regulation, one
must consider the aspects of enforcing that regulation. A regu-
lation may be set for a specific operation, a combination of
operations, or the entire processing or manufacturing facility.
From a compliance evaluation standpoint, it is desirable to have
separate standards for each affected operation in the industry.
In practice, however, it often may be difficult to do so. This
section identifies alternative air pollution control regulations
and discusses enforcement aspects of these regulations.
7.1 PROCESS CONSIDERATIONS
The crushed-stone industry is characterized by a number of
separate processing operations and emission sources, a variety of
equipment types and configurations, and feed rate and composition
variations. Some of the particulate emission sources such as
quarrying, dumping, and storage are open sources. Other operations
such as conveying and loading are frequently only partially
enclosed, while crushing and screening can be more completely
enclosed. In addition, the moisture content of the stone has a
great effect on the particulate emissions. Process feed rates
are not generally measured and some of the individual processes
may operate on a very intermittent basis.
7-1
-------
Process parameters that should be monitored to ensure that
facilities are operated normally during enforcement tests or
inspections include; the process throughput rate, the moisture
content of the feed material and the approximate size distribution
of the raw material and product. As previously mentioned, crushed-
stone plants normally are not equipped with devices for measuring
process weight rates. Based on normal screen pass-through and
recycle rates, however, the amount of material entering a pro-
cessing unit can be estimated. Guidelines are available for
making such estimates. An analysis of the moisture content of
the material processed is very important to ensure that dust
control at the time of the test is effected by the control system
and not the result of unusually high moisture levels that are not
normal for the plant. When the addition of moisture is part of
the control system (e.g., wet dust suppression), a record should
be made of the amount of added moisture required to effectively
control emissions under the worst operating and climatic conditions.
Moisture would have to be determined by taking samples of the
feed streams for subsequent analysis.
7.2 FORMATS
Air pollution regulations for this industry can be expressed
in terms of 1) quantitative particulate emission limits in terms
of concentration, mass rate, or process-weight type units, 2)
limits on visible emissions, 3) ambient air concentrations at the
plant property line, 4) equipment standards that include specifi-
cations on process and/or control equipment, operating conditions,
7-2
-------
and monitoring requirements, and 5) compatible combinations of
such measures.
7.2.1 Enforcement of Quantitative Emission Limits
Quantitative emission limits in the form of measured
concentrations or limits on the emission rate per unit of time
or throughput could be applied to crushed-stone plant process
facilities (crushers, screens, conveyor transfer points,
etc.) where emissions are captured by hoods or enclosures
and vented to a control device for collection. Determination
of particulate emissions or concentrations where control
devices are used requires a source test on the exhaust of
each control device. This involves utilization of available
test methods (EPA Methods 1, 2, 4, 5), an experienced 2 to 3
person test crew and equipment, and an expenditure on the
order of $5,000 to $7,000 per sampling location for a series
of three runs. At times, a stack may have to be modified
to provide a suitable sampling site. The cost per sampling
location will decrease when more than one is tested at a
plant. Due to the low particulate concentration expected
at the outlet of a fabric filter system, the sampling time
may have to be extended to insure adequate sample. Results
from source tests provide accurate data on particulate
concentration and emission rates.
As mentioned previously, crushed-stone plants normally
are not equipped with devices for measuring process-weight
rates. Consequently, process-weight type standards in which
emissions are related to throughput may be difficult to
enforce unless the plants are required to install process-
7-3
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weight rate monitors. In addition, in some instances more
than one process may be vented to a common control device
and only the total emissions from the connected processes
can be determined.
No special problems exist with the enforcement of
concentration or pollutant mass rate limits. It should be
noted, however, that these limits are applicable to the
control device only. As a result, other provisions (e.g.,
visible emission limits) will be needed to assure that
capture systems are properly designed and maintained.
7.2.2 Enforcement of Visible Emission Limits
Visible emission limits are especially useful for limiting
fugitive emissions from crushed-stone plant process facilities.
Indeed, visible emission limits and equipment standards
offer the only viable alternatives for limiting emissions
from process facilities controlled by suppression techniques
or for ensuring the effective capture of emissions at process
facilities controlled by local ventilation. In addition,
when used in conjunction with a quantitative emission limit
on a control device, opacity limits can be used to ensure
that the control device is properly operated and maintained.
The enforcement of visible emission limits is both
feasible and inexpensive. Determinations can be made with
a minimum of resources and require no special equipment.
For opacity determinations using Method 9, only a single
trained and certified observer is needed. In the case of
7-4
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Method 22, which assesses the frequency of visible emissions
from a source/ no special training or certification is
required and the equipment needs are limited to an accumu-
lative type stop watch (see Appendix B). The only constraint
on these methods is that readings cannot ususally be made
at night, indoors under poor lighting conditions, or during
periods of very inclement weather.
2
7.2.3 Enforcement of Equipment Standards
Equipment standards relating to the design and installation
of both equipment and control devices are feasible alternatives
for limiting emissions from some of the stone industry processes
For example, enclosure of conveyor belts, the hooding of
screens and crushers and venting through a fabric filter
system, or the utilization of water spray systems may be
specified. This format for regulation is not quantitative
but does insure that emissions will be minimized through
proper selection and utilization of equipment. Due to
the variations in crushed-stone plants, an overall equipment
standard may be difficult to apply. Such a regulation can
be used in conjunction with both quantitative and visible
emission limitations. Enforcement of equipment standards
is accomplished through plant inspections and observation by
an experienced and trained person. An inspection can be
completed in one day by a one or two person team.
Proper operation and maintenance of specified equipment
is also required to minimize emissions. Frequent plant
inspections and review of maintenance records are required
to ensure proper operation.
7-5
-------
7.2.4 Enforcement of Fence-line Standards
Ambient air particulate measurements made at a plant's
boundary can be used as an enforcement tool to help assess a
plant's overall impact on particulate concentration. The feasi-
bility of such an enforcement method is dependent on the plant
configuration, the operating schedule, and on other particulate
emission sources in the area. A number of samplers up and down-
wind of the property will be required, and these must be operated
by trained personnel. Standard procedures which must be carefully
followed and documented include:
(a) Location of sampling station(s),
(b) Records of meteorological conditions,
(c) Use of recommended sampling equipment,
(d) Careful determination of gas flow rate and sample time,
(e) Noting of any unusual conditions which may affect
sample,
(f) Proper handling of the collected sample and recording
of container and filter numbers.
The presence of other particulate sources in the area, especially
fugitive sources such as dirt roads or construction activities,
will also influence the usefulness of any measurements along a
plant boundary. Wind speed and variability will also affect the
usefulness of the results. An electrical supply is required to
operate the samplers and this may present a problem at remote
locations unless a portable electric generator is available.
7-6
-------
REFERENCES FOR CHAPTER 7
1. Pit and Quarry Handbook and Buyers Guide, 68th Edition.
Chicago, Pit and Quarry Publications, Inc. 1975-1976. p,
A9-12.
2. Technical Guidance for Control of Industrial Process Fugi-
tive Particulate Emissions. Publication No. EPA-450/3-
77-010. U.S. Environmental Protection Agency. Research
Triangle Park, North Carolina 27711.
7-7
-------
8.0 REGULATORY OPTIONS
This chapter presents a summary of the available regulatory
options for the control of particulate from crushed and broken
stone production facilities. Both process sources and fugitive
dust sources are discussed. The regulatory options are formu-
lated based on the application of alternative control methods
described in Chapter 3. Each option is discussed from the stand-
points of applicability, emission reduction, cost, environmental
impacts, and enforcement. In addition, applicable regulatory
formats are presented and, where appropriate, achievable emis-
sions are cited based on performance data presented in Chapter 3
and Appendix A.
8.1 REGULATORY OPTIONS FOR PROCESS SOURCES
The conversion of naturally occuring minerals into crushed
stone products involves a series of interrelated physical opera-
tions. Quarrying, crushing, and size classification are common
to almost all methods of mineral production. Particulates
emanate from many sources (both process and fugitive) in a
quarry and crushed stone plant. Process sources include drill-
ing, crushing and grinding, conveying and elevating (transfer
points), stockpiling (the actual operation itself) and screening.
8-1
-------
Methods for control of plant generated emissions include
wet dust suppression, dry collection and a combination of both.
8.1.1 Applicability and Performance of Control Techniques
Control Technique Descriptions--
Dry collection systems consist of an exhaust system with
hoods and enclosures to confine and capture emissions, and ducting
and fans to convey the captured emissions to a collection device
where particulates are removed before the air stream is exhausted
to the atmosphere. Depending on the physical layout of the
plant, emission sources may be manifolded to a single centrally
located collector or to a number of strategically placed units.
Appropriate ventilation rates and hood configurations are dis-
cussed in Section 3.
The most commonly used collection device for crushed and
broken stone production facilities is the fabric filter. Although
high energy scrubbers and electrostatic precipitators could
conceivably achieve results similar to those of a fabric
filter, these methods are not currently used in the industry.
As discussed in Section 3, in most crushing plant applica-
tions, mechanical-shaker collectors (which require periodic
shutdown for cleaning after 4 or 5 hours of oepration) are used.
These units are normally equipped with cotton sateen bags and
operated at an A/C ration of 2 or 3 to 1. A cleaning cycle,
normally actuated automatically when the exhaust fan is turned
off, usually requires only 2 or 3 minutes of bag shaking.
8-2
-------
Fabric filters with continuous cleaning are used where it
may be impractical to turn off the collector. Compartmented
mechanical-shaker units or pulse-jet units may be used. Pulse-
jet units normally have wool or synthetic felted bags as the
filtering medium and can be operated at a higher filtering
ratio (as high as 6 or 10:1).
In a wet dust-suppression system, dust emissions are
controlled by spraying moisture (water or water plus a wetting
agent) at critical dust-producing points in the process flow.
This causes dust particles to adhere to larger stone surfaces
or to form agglomerates too heavy to become, or remain airborne.
Thus, the objective of wet dust suppression is not to fog an
emission source with a fine mist to capture and remove emitted
particulates, but rather to prevent their emission by keeping
the material moist at all process stages.
Small quantities of specially formulated wetting agents
or surfactants are blended with water to reduce its surface
tension and consequently improve its wetting efficiency so
that dust particulates may be suppressed with a minimum of added
moisture.
Applicability--
Dry collection systems are applicable for all crushed stone
process sources. Although retrofit of dry collection systems
to existing plants (especially portable plants) may be somewhat
difficult, it is judged to be technically feasible.
Wet suppression techniques can be used to control emissions
at any process stage, or equipment where the quantity of moisture
8-3
-------
required to effectively suppress emissions can be tolerated.
In some instances, where certain end products such as concrete
aggregate are produced, wet dust suppression may not be applicable
unless these materials are subsequently treated in a wash plant
for fines removal because of the specifications on the content
of fines. In addition, wet controls may not be functional at
extremely low temperatures because of freezing.
Performance--
As discussed in Section 3, dry collection systems are
capable of achieving high levels of emission reduction. Although
impractical to quantify, if adequate hooding and ventilation
rates are applied, essentially complete capture can be achieved.
Visual observations made at crushed stone process facilities
at three plants using dry collection techniques to control
emissions showed that emissions escaping capture from properly
designed and operated capture systems are slight with visible
emissions typically occurring less than 10 percent of the time
and seldom exceeding 5 percent opacity. Based on uncontrolled
emission estimates and measured outlet data, the application of
fabric filter collectors (either mechanical shaker or pulse-jet
type) should achieve greater than 99 percent collection
efficiency on captured emissions from crushed stone process
facilities. Mass particulate measurements conducted by EPA
at the outlet of twelve fabric filter collectors at five crushed
3
stone plants averaged 0.011 g/Nm (0.005 gr/dscf) and did not
3
exceed 0.034 g/Nm (0.015 gr/dscf). In addition, visual
8-4
-------
observations made at the outlet of each of the fabric filters
tested showed no visible emissions at 10 of the 12 and only
slight emissions ranging from 0 to 5 percent opacity at the
other two with the highest six minute average recorded being
1.0 percent.
As noted in Section 3, a quantitative assessment of the
effectiveness of wet dust suppression techniques in reducing
mass particulate emissions from crushed and broken stone process
facilities is not practical. However, visual observations can
be used to provide some indication of performance. Visual
observations made by EPA at numerous process facilities at
five plants where particulate emissions are controlled by
wet dust suppression techniques showed that, where properly
designed and operated, wet suppression systems offer a viable
control alternative to dry collection at process facilities
(both crusher and non-crusher sources) that can tolerate the
amount of added moisture necessary for effective control. The
results obtained indicate that emissions from crushers are
generally greater than those from non-crusher sources. Visual
observations made at twelve crushers including jaw, impact
and cone type crushers showed that emissions were generally
continuous (visible over 70 percent of the time on average)
and typically exceeded 10 percent opacity- In contrast, emissions
from non-crusher sources (screens and conveyor transfer points)
were generally intermittent (visible less than 90 percent of
the time) and typically less than one percent in opacity (six-
minute average).
8-5
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Although not specifically evaluated, it is reasonable to
assume that performance levels for combination systems is essential-
ly equivalent to that demonstrated for the use of dry collection or
wet suppression alone.
8.1.2 Cost, Energy, and Environmental Considerations
Table 8-1 summarizes the estimated energy, envionmental,
and cost impacts for application of dry collection and wet
suppression to the three model plants presented in Section 4.
These incremental impacts are computed against an uncontrolled
emission baseline.
Air--
The application of dry collection systems to crushed and
broken stone process sources should result in substantial reduction
in emissions. Based on the estimates developed in Section
5.1, greater than 98 percent reduction over uncontrolled
emissions is projected.
Since particulate emissions from process facilities controlled
by wet suppression techniques are impractical to quantify, no
quantitative data are available on their emission reduction
potential except to say that comparable emission reductions can
apparently be achieved using wet dust suppression or combination of
wet and dry systems where these control systems are properly operated
and maintained.
Water Pollution--
Dry collection techniques using fabric filters generate
no water effluent. Water used for wet suppression is absorbed
by the material processed. It is therefore concluded that
application of air pollution control technology to the crushed and
broken stone processes has no significant impact on water quality
8-6
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Solid Waste--
Solid waste in the form of fine stone dust generated by thi
application of dry collection methods at crushed and broken stone
processes can be sold or used for a variety of purposes. Al-
ternatively, the dust can be disposed of in isolated locations
in the plant quarry with no subsequent air pollution problem
provided the waste pile is controlled by one of the methods
discussed in Section 3. Thus, wet suppression and dry collection
control systems have a negligible impact as far as solid waste
disposal is concerned.
Energy--
The only significant increase in energy consumption over
an uncontrolled plant occurs when a fabric filter is used for
particulate collection. The additional energy is for operation
of fans, air compressors, and screw conveyors associated with
operation of the fabric filter. The increase in energy is
estimated to range from 16 to 19 percent higher than the un-
controlled plant, as shown in Table 8-1.
In contrast, additional energy required to operate the
wet suppression system is less than one percent.
For a combination wet-dry collection system the increase
in energy consumption is about 6 percent for each plant size.
Noise--
Compared with the noise emanating from crushed stone
process equipment, additional noise from control system exhaust
fans is likely to be insignificant.
8-7
-------
Cost--
The overall costs of the control alternatives for crushed
stone production are shown in Table 8-1. Use of fabric filters
for dry collection is the most expensive control alternative
(both capital investment and annualized costs) followed by the
combination wet-dry collection system, with the wet suppression
system being the least expensive control option.
The capital investment (in 1976 dollars) for fabric
filters at the three model plant sizes, ranges from $145,000 to
$340,000 compared to a range of $131,000 to $188,000 for com-
bination systems, and $66,000 to $76,000 for wet suppression.
Unit costs follow the same pattern, with dry collection
costs ranging from 9.5 to 13.7c/Mg (8.5-12.5c/ton) of production,
combination systems from 5.1 to 10.6c/Mg (4.6-9.6c/ton), and we:
suppression from 2.0 to 4.5c/Mg (1.8-4.lc/ton).
Thus, combination systems are less expensive than dry
collection alone, and wet suppression is the least costly control
alternative, where it can be used.
8.1.3 Alternative Formats and Emission Limits
The various formats available for regulating particulate
emissions were discussed in Section 7.
For dry collection, regulations should limit emissions
both from collection device and at the points of capture.
Alternative formats for the collection device include
quantitative emission limits in concentration, mass rate and
process-weight rate units; limits on opacity of visible emissions;
8-8
-------
and equipment standards. Alternative formats for regulating
fugitive emissions at capture points include limits on the
opacity or duration of visible emissions and equipment standards.
Enforcement of quantitative emission limits in process
weight units would require that devices which measure process
weight rates be installed on belts feeding process equipment.
Concentration units would be simpler to enforce than the
process-weight standard, since they do not require that a
weight measuring device be installed. As noted in Section
8.1.1, data obtained on fabric filters controlling crushed
stone process facilities indicate that an outlet loading of
3
performance 0.03 g/dry m (0.013 gr/dscf) or less, can be
achieved. In addition, the opacity of emissions discharged by
the collection device could be limited to 1 percent (six
minute average). For fugitive emissions discharged at capture
points (i.e., hoods and enclosures), a visible emission
limitation which would limit visible emissions to no more than
10 percent of the time is achievable.
For equipment standards (fabric filters in this instance),
the air-to-cloth ratio, cleaning method, pressure drop, con-
figuration of capture hoods and enclosures, and capture
velocities would need to be specified (see Section 3). Compliance
with these specifications would be determined by the control
agency as a part of their permit or licensing program.
For wet dust suppression, regulations would limit emissions
at the point of generation. Quantitative emission limits do
8-9
-------
not seem reasonable for wet suppression control because an emission
capture system would need to be built to measure the decrease
in emissions and, while technically possible, testing would be
costly. As a result, alternative formats that could be applied
are limited to visible emission limits on the opacity or duration
of emissions and equipment standards.
As noted in Section 8.1.1, visible emissions from non-crusher
sources controlled by wet dust suppression were found to be
intermittent while those from crushers were generally continuous.
Because of this distinction, a different format for limiting visible
emissions should be applied to each class of sources. For
non-crusher sources characterized by intermittent emissions, a
visible emission limitation which limits the duration of emissions
is more appropriate than an opacity limit. For crusher sources
with continuous emissions, an opacity limit presents the only
alternative. Based on the performance data presented in Section 3
and discussed in Section 8.1.1, an achievable standard for non-
crusher sources would limit visible emissions to no more than
10 percent of the time. For crushers, visible emissions could
be limited to 15 percent opacity. These visible emission limits
should insure that sufficient water is used in the wet suppression
system to provide effective control of particulate.
If equipment standards were applied, specifications would
include configuration of nozzles, spray pressure, and the amount
of moisture to be added.
8-10
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8,2 REGULATORY OPTIONS FOR FUGITIVE DUST SOURCES
Fugitive emissions are generated by blasting, loading, hauling,
stockpiling (e.g., free fall), and also are windblown from roads,
plant yards, and stockpiles. Various treatments include watering,
wet dust suppression, surface treatment with chemical dust
suppressants, soil stabilization, and paving. Table 3-1 summarizes
control options from fugitive dust sources in the crushed stone
industry.
8.2.1 Control Technique Descriptions, Applicability and Performance
The most commonly used fugitive dust control methods used are
summarized in this section.
Control Technique Descriptions and Applicability--
No effective method is available for controlling fugitive
emissions from blasting operations, except to try and schedule
blasting operations during conditions of low wind and low in-
version potential.
Quarry loading operations are sometimes controlled by water-
ing as are hauling operations. Other control techniques used to
control haul roads include oiling of roads, the application of
hygroscopic chemicals (substances that absorb moisture from the
air), the use of soil stabilizers, consisting of a water dilutable
emulsion of either synthetic or petroleum resins that act as an
adhesive or binder, and paving of roads.
Wet dust suppression is sometimes used for control of fugi-
tive emissions from stockpiles, as are devices designed to reduce
the free-fall distance of the materials, such as stone ladders,
8-11
-------
telescopic chutes, and hinged boom stacker conveyors. However,
watering is the most commonly used technique for active stock-
piles. Soil stabilizers are sometimes used with reasonable
success on inactive stockpiles.
Chemical suppression and covering are the two methods used
for control of fugitive emissions from conveying operations,
covers being the most effective.
Loadout operations are generally uncontrolled, but at some
installations attempts are made to wet the material either prior
to or during loading. Enclosing the area under loading bins
also reduces the potential for windblown emissions.
Fugitive emissions from plant yard areas are generally
uncontrolled, and in cases where some control is exercised,
similar methods to those used for haul roads are employed.
Performance--
Since minimal data are available for quantifying emissions
from fugitive dust sources, the performance of various methods of
control cannot be accurately estimated. The effectiveness of the
most commonly used methods depends on the amount of water or
chemical applied, the frequency of application, weather condi-
tions, and conditions of the road or material being treated.
8.2.2 Cost, Energy, and Environmental Considerations
This section summarizes the environmental, energy, and cost
impacts of available data on control techniques for reducing
fugitive emissions from crushed stone sources presented in
Section 4.
8-12
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Air Impact--
As stated previously, fugitive dust sources are typically
large in area and emissions are discharged to the atmosphere
in an unconstrained manner, rather than through a stack. Therefore,
quantitative measurement of these emissions would be very difficult.
Consequently, estimates are not available on the impact of imple-
menting controls for fugitive dust.
Water Impact--
No data are available to assess the impact on water quality
associated with various roadway treatments. However, it is
believed that the impact on water quality would be negligible.
Solid Waste Impacts--
The control techniques used for control of fugitive dust
emissions from crushed stone processes would have no impact on
solid waste.
Energy Impact--
Minimal data are available on increased energy use related
to use of control .techniques for fugitive dust control. It is
expected, however, that the energy impact would be small in
comparison to the energy requirements for quarry and plant
operations.
Cost Impact--
Of the five control techniques listed in Section 4 (See
Tables 4-12 and 4-12a) for controlling fugitive emissions from
unpaved roads, the capital investment for truck speed reduction
at $150,000 is 5 times more expensive than other techniques, such
as paving, vacuuming, and oiling: and 10 times more expensive
8-13
-------
than the most inexpensive technique, watering. The annual costs
of truck speed reduction at $87,500/yr are 3 to 10 times more
expensive than other competing techniques.
Costs of retrofitting covers on existing conveyors is esti-
mated at $35 to $70/ft of conveyor length. Since conveyor covers
require little maintenance, annual costs consist largely of in-
direct capital charges.
Typical capital costs of control for storage piles are
estimated at $20,000 per 9.1 m (30-ft) pile for a stone ladder,
$26,000 to $42,000 per telescoping chute, $772 per Mg ($700 per
o
ton) of throughput for a movable stacker, and $105 to $263 per m
-3
($80 to $200 per yd ) for enclosures (see Table 4-14). Again,
annual costs depend mainly on remaining plant life and the cost
of capital.
Sprinkler systems for stockpiles are estimated to cost from
a few thousand dollars to $20,000, depending on the plant. Costs
of spraying storage piles are estimated to range from $0.01 to
$0.06 per Mg ($0.05/ton), depending on the chemical used, the
number of storage piles, and the frequency of spraying.
All of the above costs are in 1976 dollars.
8.2.3 Alternative Formats and Emission Limits
Quantitative emission limits are not considered applicable
to fugitive dust sources in the crushed stone industry because
no practical method of measurement is available.
The use of visible emission limits in terms of opacity and
as percent of time when the emission limits are visible is especially
8-14
-------
useful for fugitive sources of particulate. However, care must
be taken to obtain readings under representative conditions,
because of the intermittent operation of some processes and the
variation in emissions caused by climatic conditions.
In formulating specific visible emission regulations for
fugitive dust emissions in the crushed stone industry, test
programs would be required for monitoring opacity of visible
emissions for such control techniques as different vehicle speeds
and weights, frequency of watering or oiling, and effect of
weather conditions.
In the absence of visible emissions data, and the lack of an
established, practical method to measure the amount of particulate
being emitted by fugitive dust sources, the equipment standard or
work practice standard may be the most suitable format. For
fugitive dust sources, this format is in the form of a "perform-
ance standard," that specifies the manner in which the sources
should be constructed or operated. Equipment standards can be
specified for some fugitive dust source, such as enclosures for
open conveyors. These standards are not quantitative but would
ensure that emissions will be minimized through proper selection
and utilization of equipment.
Ambient air measurements made at a plant's boundary can be
used to help assess a plant's overall impact, including fugitive
dust emissions, on particulate concentration. Enforcement
problems may arise because of the presence of other particulate
sources in the area, such as unpaved roads or construction
8-15
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activities that generate fugitive emissions. These sources
may adversely influence the usefulness of measured data.
As far as a general regulation covering fugitive dust emissions
is concerned, many states use a performance-type regulation
patterned after the one contained in 40 CFR 51, Appendix B, for
regulating fugitive particulate emissions. The typical state
regulation recommends that "reasonable precautions" be taken to
minimize the potential of fugitive dust emissions and suggests
some general techniques to achieve this goal. The enforcement
problems associated with this type of "reasonable precautions"
regulation can be alleviated by the careful specification of
precautions, i.e., source specific performance standards.
A regulation may require the implementation of one or
more of the control alternatives. For example, a regulation
may require that all conveyors be covered, or the regulating
agency may desire to exercise its discretion, depending upon
factors such as the proximity of dust emitting operations to
human habitations or activities and atmospheric conditions that
might affect the dispersion of particulate matter. The following
model performance standard regulation for fugitive dust sources
associated with crushed-stone production incorporates source
specific control measures with a provision for discretion;
(a) No person shall operate or maintain, or cause to be
operated or maintained, any premise, open area, right-
of-way, storage pile of materials, or any other process
that involves any handling, transporting, or disposition
of any material or substance likely to be scattered by
the wind, without taking reasonable precautions, as
approved by the regulating agency, to prevent particu-
late matter from becoming airborne.
8-16
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(b) In obtaining approval under subsection (a) of this
section, the regulating agency may impose one or more
of the measures and any operating conditions it deems
necessary to attain and maintain compliance with the
provisions of this section.
8.3 REGULATORY OPTIONS FOR DRILLING
Two methods are generally used to control particulate emissions
from drilling operations: water injection and aspiration to a
control device.
8.3.1 Control Technique Descriptions, Applicability and Performance
Water injection is a technique in which water and a wetting
agent or surfactant is forced into the compressed air stream that
flushes the drill cuttings from the hole. The water injection
produces a mist that dampens the stone particles and causes them
to agglomerate, and drop at the drill collar rather than becoming
airborne.
The use of a wetting agent allows the use of less water for
effective control, by reducing the surface tension of the un-
treated water.
Dry collection systems are also used to control drilling
emissions. A shroud or hood encircles the drill rod at the
hole collar, and a vacuum captures emissions and vents them
through a flexible duct to a control device, most commonly
a fabric filter, preceded by a settling chamber.
Fabric filter performance should be equivalent to that
achieved on other crushed stone process facilities. As indicated
in Chapter 3, visible emission tests for a rotary drill equipped
with a fabric filter showed opacities of 0 to 5 percent at the
fabric filter and less than 20 percent at the capture point for
greater than 75 percent of the observation time.
8-17
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8.3.2 Environmental, Energy, and Cost Considerations
The environmental, energy, and cost impacts of applying
fabric filters as a dry collection technique or water injection
as a wet collection technique have not been assessed.
8.3.3 Alternative Formats and Emission Limits
Applicable formats for limiting particulate emissions from
drilling operations controlled by dry collection include quantita-
tive emission limits, visible emission limits, and equipment
standards.
A concentration limit applied to the fabric filter should be
equivalent to that achievable by other fabric filters applied
on other crushed stone process facilities. Limitations on visible
emissions (e.g., less than 10 percent opacity from the fabric
filter and less than 20 percent from the hole collar), would
ensure proper operation of the fabric filter and would ensure
maintenance of an adequate aspiration rate at the capture point.
However, since drilling is an intermittent operation and emissions
can vary because of climatic conditions, care must be taken to
obtain readings under representative conditions.
Equipment standard specifications that could be required are
the air-to-cloth ratio, cleaning method, pressure drop, and
aspiration rate.
Applicable regulation formats for water injection are visible
emissions and equipment specifications. Limitations on visible
emissions (less than 20 percent opacity at the hole collar) will
ensure proper design, operation, and maintenance of water injection
systems.
The only important equipment specification is the rate of
8-18
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water injection to ensure that sufficient water is used for
effective collection.
8.4 SUMMARY
A matrix summarizing the environmental and cost impacts
resulting from the application of alternative emission control
systems is presented in Table 8-2. Impacts are rated as beneficial
or adverse; the magnitude as negligible, small, moderate, or large;
and the duration as short term, long term, or irreversible.
8-19
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Table 8-2. MATRIX OF ENVIRONMENTAL AND ECONOMIC IMPACTS
Alternative emission
control systems
Wet suppression for
crushed stone plant
process facilities
Dry collection for
crushed stone plant
process facilities
Combination wet and
dry for crushed stone
plant process facili-
ties
Dry collection for
drilling equipment
Liquid injection for
drilling equipment
Air
impact
+ 3**
+ 3**
+ 3**
+2**
+2**
Water
impact
0
0
0
0
0
Solid
waste
impact
0
_2
-2
-1
0
Energy
impact
-1
-2
-2
-1
-1
Noise
impact
0
_!**
_!**
_!**
0
Oc-
cupa-
tional
health
impact
+3**
+3**
+ 3**
+2**
+2**
Cost
impact
_2**
-2
to
-3**
-2**
-2**
_!**
OO
I
to
o
Key: + Beneficial impact
Adverse impact
0 No impact
1 Negligible impact
2 Small impact
3 Moderate impact
* Short-term impact
** Long-term impact
-------
APPENDIX A
SOURCE TEST DATA
A test program was undertaken by EPA to evaluate available
techniques for controlling particulate emissions from crushed
stone plant process facilities including crushers, screens
and material handling operations, especially conveyor transfer
points. Both dry control (capture and collection) and wet
suppression techniques were evaluated. In addition, the use
of capture and collection on a drilling operation were also
evaluated. Presented in this appendix is a description of
each facility tested, and complete test data summaries for
both mass particulate measurements and visible emission
observations.
DRY COLLECTION
Twelve bs.ghouse collectors which control emissions from
plant facilities at five crushed stone installations were
tested. A baghouse collector used to control particulate
emissions from a drilling operation at a limestone quarry
was also tested. Salient facts on each of the baghouse
collectors tested including the filtering ratio, the volumetric
flow-rate handled and a description of the process facilities
serviced are summarized in Table A-l. A minimum of three test
runs were conducted, using EPA Reference Method 5 for the
determination of particulate matter, on each of the baghouses
tested. During these tests, testing was stopped and restarted
to allow for intermittent process 'shut-downs and upsets (no stone)
A-l
-------
Table A. PROCESS FACILITIES CONTROLLED BY BAGHOUSE UNITS TESTED
Baghouse specifications
Rock type Filtering Capacity
cilit
Al
A2
A3
A4
Bl
B2
y processed
Limestone
Limestone
Limestone
Limestone
Limestone
Limestone
Type
Jet
Jet
Jet
Jet
pulse
pulse
pulse
pulse
Shaker
Shaker
5
5
3
2
ratio
.3
7
7
.2
.1
.1
to
to
to
to
to
to
1
1
1
1
1
1
scfm
26472
15811
2346
10532
5784
18197
Cl Limestone Shaker
C2 Limestone Shaker
Dl Traprock Shaker
E2
2.3 to 1 7473
2.0 to 1 6543
2.8 to 1 31863
D2 Traprock Shaker 2.8 to 1 25960
\
El Traprock Jet pulse 5.2 to 1 14748
Traprock Jet pulse 7.5 to 1 21122
Limestone Shaker
(manual)
2.5 to
663
Process facilities
controlled
Primary impact crusher
Primary screen
Conveyor transfer point
Secondary crusher (cone) and screen
Primary impact crusher
Scalping screen, secondary cone crusher,
hammer mill, two tertiary cone crushers,
two finishing screens, five storage bins,
and six conveyor transfer points
Primary jaw crusher (discharge), scalping
screen, and hammer mill
Two finishing screens and two conveyor
transfer points
Scalping screen, secondary cone crusher,
two sizing screens, two tertiary cone
crushers and several conveyor transfer
points
Finishing screen and several conveyor
transfer points
Two sizing screens, four tertiary cone
crushers and several conveyor transfer
points
Five finishing screens and eight storage
bins
Rotary drill
-------
Where the process weight rate was undeterminable at a suecific
plant facility, as in most instances, the process weight
through the primary crushing stage was monitored to assure
that the plant was operating at or near normal capacity.
Also determined was the moisture content of the processed
stone at each plant (except for plant A) to ensure that
emissions were controlled by the dust collection system and
not by abnormally high moisture content in the material
processed. Results of the front-half catch (orobe plus
filter) for each sample run conducted are shown in Figures A-
1 and A-2 in terms of concentration and mass rate respectively.
Excluding the measurements made at facility F, the emission
concentration of the control devices tested averaged 0.005 gr/dscf
and did not exceed 0.013 gr/dscf. The results of the measurements
performed at facility F (rotary drill) averaged 0.039 gr/dscf.
It is suspected that since this collector utilized a manually
operated shaker mechanism, it may have been subjected to over-
cleaning and, consequently, poor filter cake buildup.
In addition to the particulate measurements described
above, visible emissions observations were also made. The
opacity of the emissions exhausted by each of the 12 baghouses
tested was recorded in accordance with EPA Reference Method
9 procedures. No visible emissions were observed from the
fabric filters at plants A, C, D and E. Slight emissions
ranging from 0 to 5 percent opacity were observed at Bl and B2.
The highest six minute average recorded at each of these
A-3
-------
0.015
•M
O
O
**• o.oio
o
1/1 !S
I 3
•^ -o
^r- f
Cu "^
^ 5
i ^
j— ,
i «
c
i-
cr>
0.005
n
_ KEY ft
Ii
n M '
U-fl AVERAGE | 1 1
i ' it
d i ||
€>EPA TEST METHOD H^ d
1 1 1
O OTHER TEST METHOD . q^
| 1
M
1 1
i i
1 '
. i
« J
ii r
' H~H
i r '
ct)
1
1
1 I
; !
fj-fl 1 P 0.055
1 1 1 1
"~ E i ^ ' i
i n
! doi ^ (P rrrl 0.039
1 rn i | n 1 1
i . Ii. ! ' ic 0.032
I M ii g
^N I | | 1 1 jl , , V
V i irj i i i
rp|1 1 ' '
1 1 U ' '
f fll 1
Facility Al A2 A3 A4 Bl B2 B3 Cl C2 Dl D2 El E2 F
Rock Type L L L L L L L L L T T T T L
Figure A-l
Particulate emissions from crushed stone facilities
A- 4
-------
2.5
2.0
I/O
o
«/) 3
CO O
z ^ 15
UJ S. ' * J
O)
UJ Q.
O 3
•-« O
»— Q.
ce
o.
1.0
0.5
Facility
Rock Type
P
1
KEY |
r^ AVERAGE ft
_ id n i
0 EPA TEST METHOD ' ' '
1 1 r""H
0 OTHER TEST METHOD ,i|, |
Tr i
I
cb '
i
i
n i
ii [
Ti d
h
— 1^
p
i
i
i
-•jj1
P 1 1 h
11 n ulli
1 | | rfp
1 . . 1 1 1 1 1
Mil : » | 1
n 1 i I i Id
TP I! ii W
•j i i «t i •
y R ijjj *^
l^tl iTjJlllll
Al A2 A3 A4 Bl B2 B3 Cl C2 Dl D2 El E2 F
LLLLLLLLLTTTTL
Figure A-2
Particulate emissions from crushed stone facilities.
A- 5
-------
three baghouses was 1.0 and 0.8 percent opacity, respectively.
Observations of visible emissions were also made at the
capture hoods and enclosures installed on many of the process
facilities controlled by the baghouses tested at plants A, B and
D to determine the presence and opacity of emissions escaping
capture. Eight crushers, six screens, one conveyor transfer
point and one surge bin were observed. A^ain, EPA Reference
Method 9 was used. The results, however, are presented in terms
of the total time emissions were observed equal to or greater
than a specified opacity rather than in six minute averages.
Table A-2 lists the specific process facilities observed
and the results obtained in terms of the percent of time over a
stated observation period that visible emissions occurred. In
most cases (10 of 16) no visible emissions were observed over
the entire observation period. At the six process facilities
where visible emissions were observed, the emissions observed
were slight (seldom exceeding 5 percent opacity) and occurred
less than 10 percent of the time.
WET DUST SUPPRESSION
Due to the nature of wet dust suppression, the quantitative
measurement of mass particulate emissions at process facilities
controlled by wet dust suppression techniques is impractical.
However, some assessment of the effectiveness of this technique
can be made by visual observation.
Visual observations were made at numerous process facilities
(crusher, screens and conveyor transfer points) at five installa-
A-6
-------
TABLE A-2. SUfMARY OF VISIBLE EMISSION OBSERVATIONS AT CAPTURE HOODS OR
ENCLOSURES ON CRUSHED-STONF. PLANT PROCESS FACILITIES
Plant/Rock type processed
A Crushed limestone
B Crushed limestone
D Crushed stone
Process facility
Primary impact crusher discharge
Conveyor transfer point
Scalping screen
Surge bin
Secondary cone crusher No. I
Secondary cone crusher No. 2
Secondary cone crusher No. 3
Hammer mill
3-dcck finishing screen (L)
3-dcck finishing screen (R)
No. 1 tertiary gyrasphere cone crusher
No. 2 tertiary gyrasphere cone crusher
Secondary standard cone crusher
Scalping screen
Secondary (2-deck) sizing screen
Secondary (3-deck) sizing screen
Accumulated observation
tyme (minutes)
240
166
287
287
231
231
231
287
107
107
170
170
ro
:io
210
210
Accumulated emission
time (minutes)
4
3
45
3
23
0
0
0
4
0
0
0
0
0
0
0
Percent of tine
with visible emissions
1
2
15
1
10
0
0
0
4
0
0
0
0
0
0
0
-------
tions where particulate emissions generated are controlled by
wet dust suppression techniques. The installations included
two portable and three stationary plants. The visual observa-
tions were made using both EPA Reference Methods 9 and 22. A
listing of the process facilities observed and a summary of the
results obtained are presented in Table A-3. Complete results
are presented in the Tables 'herein.
The results obtained indicate that emissions from crushers
are generally greater than those from non-crusher sources. Visual
observations made at twelve crushers including jaw, impact
and cone type crushers showed that emissions were generally
continuous (visible over 70 percent of the time on average)
and typically exceeded 10 percent opacity. In contrast, emissions
from non-crusher sources (screens and conveyor transfer points)
were generally intermittent (visible less than 90 percent of
the time) and typically less than one percent in opacity (six-
minute average).
DESCRIPTION OF FACILITIES
Al. Primary crushing stage incorporating a pan feeder,
vibrating grizzly, impact breaker, T-bar belt feeder and a
primary belt conveyor. The impactor is rated at 1,000 TPH
and used to reduce run-of-quarry limestone (cement rock) to
A-8
-------
TABLE A - 3
SUMMARY OF VISIBLE EMISSION OBSERVATIONS FROM CRUSHED STONE PROCESS FACILITIES
CONTROLLED BY WET DUST SUPPRESSION
vo
Plant
EPA Method 22
Process Facilities Observation time Percent of time
(minutes) Emissions visible
Observation time
(minutes)
EPA Method 9
Highest Average
Six-Minute Average Oracity
G
H
I
J
K
Primary Jaw Crusher
Scalping Screen
Secondary Impact Crusher
Secondary Screen
Tertiary Cone Crusher
Conveyor Transfer Point
Primary Jaw Crusher
Scalping Screen
Conveyor Transfer Point
Secondary Screen
Secondary Cone Crusher
Finishing Screens
Scalping Screen
Primary Jaw Crusher
Conveyor Transfer Point
Secondary Screens
Secondary Cone Crusher
Finishing Screens
Conveyor Transfer Point
Conveyor Transfer Point
Primary Jaw Crusher
Scalping Screen (2-deck)
Secondary Cone Crusher (4 1/2')
Secondary Screen
Secondary Cone Crusher (5 1/2')
Conveyor Transfer Point
Conveyor Transfer Point
Primary Jaw Crusher
Conveyor Transfer Point
Secondary Screen (3-deck)
Secondary Cone Crusher (4 1/4')
Storage Bin
20
—
20
60
—
60
60
60
60
120
30
120
120
30
30
120
30
120
60
60
60
120
30
120
30
120
120
30
120
120
30
120
69
--
96
0
--
1
53
36
49
0
95
0
3
93
12
9
99
0
0
2
5
0
68
10
25
0
0
65
2
0
100
0
102
60
60
60
120
60
120
120
120
120
120
120
120
120
60
120
120
120
60
60
120
120
1?0
120
120
1?0
120
KM
l.'O
120
120
120
21
12
15
0
25
3
18
10
14
2
39
< 1
3
17
5
5
17
1
0
3
3
0
5
4
If,
0
0
11
v
*
>
A
< 1
}
0
c
;
V
j
i7
, 1
-------
minus 2 1/2-inch. Particulate emissions generated at vari-
ous points are captured and vented to a jet pulse type
baghouse for collection.
A2. Primary screen used for scalping the primary
crusher product of facility Al. The plus 2 1/2-inch over-
size is chuted to a belt conveyor and returned to the pri-
mary for recrushing. The screen throughs are also dis-
charged to a conveyor and transported to a storage facility.
Particulate emissions generated from the top of the screen,
which is totally enclosed, and from both chute-to-belt
transfer points are aspirated to a jet pulse baghouse for
collection. Particulate emission measurements were con-
ducted simultaneously with those at facility Al. Sampling
during all three test runs reported herein was overiso-
kinetic.
A3. Conveyor transfer point at the tail of an overland
conveyor, also located at installation Al. The 30-inch belt
conveyor has a 900 TPH capacity at a belt speed of 700 FPM.
The transfer point is enclosed and emissions are vented to
a small baghouse unit for collection.
A4. The secondary crushing and screening stage at
installation Al consisting of a vibrating screen and a cone
crusher. Minus 2 1/2-inch material is fed to the screen at
about 165 TPH where it is separated in two fractions, plus
A-10
-------
3/4-inch and minus 3/4-inch. The oversize fraction is
discharged to the cone crusher and reduced to 3/4-inch. The
crusher product and screen throughs are then conveyed to a
milling circuit. Dust control is effected by capturing and
venting emissions from the screen and crusher to a jet pulse
baghouse for collection.
Bl. Primary impact crusher used for the initial reduc-
tion of run-of-quarry limestone rock to three inches. The
normal production rate through this primary crushing stage
is 350 TPH. From the discharge hopper underneath the impact
crusher and from the discharge hopper/primary conveyor belt
transfer point, particulate emissions are vented to a fabric
filter for collection. The fabric filter is mechanically
shaken twice daily for cleaning.
B2. Secondary and tertiary crushing and screening
facilities at the same installation as Bl. These consist of
a scalping screen, a 4-foot cone crusher, two 3-foot cone
crushers, a hammermill used to produce agstone and two final
sizing screens. The plant has a 300 TPH designed capacity,
crushing to minus 1 1/2-inch, including, 60 TPH of agstone.
Throughout this plant emissions from dust producing points
are captured by hoods and enclosures, and vented to a fabric
filter for collection. The collector is mechanically shaken
twice daily for cleaning. Pickup points include the top of
A-ll
-------
the scalping screen, both the feed and the discharge of all
three cone crushers, the discharge of the hammermill, the
top of both finishing screens, five product bins and six
conveyor transfer points.
B3. The same facility as B2, except that particulate
emission measurements were made using an in-stack filter.
Testing was conducted simultaneously with that described in
B2.
Cl. Limestone crushing plant consisting of a primary
jaw crusher, scalping screen and hammermill. The rated
capacity of the plant is 125 TPH. End products produced
range from minus 1 1/2-inch dense-graded road base stone to
minus 1/8-inch screenings. Particulate emissions are con-
trolled by a mechanical shaker type baghouse. Ventilation
points include the primary crusher discharge, the scalping
screen throughs/stacking conveyor transfer point, and both
the hammermill feed and discharge. Tests were conducted
using EPA Methods 5 and 9.
C2. Two 3-deck vibrating screens used for final sizing
at the same installation as Cl. Both screens are totally
enclosed. Particulate emissions, which are collected from
the top of both screens, from the feed to both screens, and
from both the head and tail of a shuttle conveyor between
the screens, are vented to a mechanical shaker type baghouse,
A-12
-------
Dl. Secondary and tertiary crushing and screening
facilities used for processing traprock at 250 TPH. The
process facilities include a scalping screen, a 4-foot
secondary cone crusher, two sizing screens and two 4-foot
tertiary cone crushers. All process facilities are enclosed
and particulate emissions are vented to one of two baghouses
for collection. The baghouses are exhausted through a
common stack.
D2. Finishing screen at the same installation as
facility Dl. The screen is totally enclosed and emissions
are vented to a fabric filter. Emissions are collected from
the top of the screen enclosure, all screen discharge
points, and several conveyor transfer points. Tests con-
ducted were identical to those at Dl and were performed
simultaneously.
El. Tertiary crushing and screening facilities at a
375 TPH traprock installation. Process facilities include
two sizing screens, four 4 1/4-foot cone crushers and several
conveyor transfer points. Both screens are enclosed and
emissions are aspirated from the top of the enclosures and
from the throughs discharge. The tertiary cone crushers are
hooded and vented at both feed and discharge points. Captured
emissions are vented to a jet pulse type baghouse for col-
lection. Although desirable, the pressure drop across the
A-13
-------
baghouse could not be monitored because the pressure gauge
was inoperative.
E2. Five screens used for final sizing, and eight
storage bins at the same installation as El. All screens
and bins are totally enclosed and emissions are vented to a
jet pulse type baghouse for collection. Tests conducted
were identical to and performed simultaneously with those at
facility El.
F. Rotary drill used to drill 5" X 80' blastholes at a
limestone quarry. Particulate emissions were aspirated from
the drill collar to a baghouse for collection. Only one point
was sampled and the duration of each test run coincided with
the time required to drill a hole. Visible emission observa-
tions were made concurrently with the particulate measurements.
G. Facility G produces crushed stone used primarily for
road construction purposes. The processing operation is
located in the bottom of an open quarry. The quarried materials
are carried by truck to the upper rim of the pit where they
are dumped into hoppers which feed the processing equipment.
The finished product is transported back out of the quarry by
belt conveyor.
Visible emission measurements were conducted at the primary
(jaw), secondary (impact), and tertiary (cone) crushers, two
process screens, and one conveyor transfer point by means of
EPA Reference Methods 9 and 22. All process sources of emissions
are directly or indirectly controlled by means of a wet
suppression system.
A-14
-------
H. This facility produces two grades of rock for road-base
and decorative stone, respectively. The ore is obtained from an
open mining operation at the top of a mountain, and the proces.s
equipment is permanently installed in a decending arrangement
from the mine site to the bottom of the mountain. The processed
rock is accumulated in bins at the lower level for subsequent
truck loading.
Visible emission measurements using the same techniques as
Facility Q were conducted at the primary (}ar), and secondary
(cone) crushers, three process screens, and one conveyor transfer
point all controlled by means of a wet suppression system.
I. A fully portable crushing plant processes bank-run
material for road construction and as concrete component. Ore
is removed from a gravel bank and trucked to the bank top for
dumping into the initial screens before the primary crushers.
Wet suppression techniques are used to control fugitive dust
emanating from the processing of the material.
EPA Reference Methods 9 and 22 were used to measure
visible emissions from primary (jaw), and secondary (cone)
crushers, three process screens, and two conveyor transfer points.
J. The facility produces two grades of crushed granite.
The plant is relatively new with all process equipment located
at ground level. One jaw crusher, two cone crushers, two
process screens and two conveyor transfer points are all directly
or indirectly controlled by means of wet suppression systems.
A-15
-------
EPA Reference Methods 9 and 22 were employed to measure
visible emissions emanating from the above named process
sources.
K. A large semi-portable rock crushing facility
processing large-size grades of crushed limestone was tested
for visible emissions by means of EPA Reference Methods 9
and 22.
The sources tested were the primary and secondary (cone)
crushers, one process screen, one conveyor transfer point, and
one storage bin. All sources tested are controlled by wet
dust suppression.
A-16
-------
TABLE 1
FACILITY Al
Summary of Results
Run Number
1
Average
Date
6/10/74 6/11/74 6/12/74
Test Time - Minutes
Production Rate - TPH^
Stack Effluent
Flow rate - ACFM
Flow rate - OSCFH
Temperature - °F
Water vapor - Vol. X
Visible Emissions at
Collector Discharge -
% Opacity
Parti cul ate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF*2)
gr/ACF
Ib/hr
Ib/ton
400
995
26430
22351
81.0
2.5
0.00471
0.00398
0.90
0.00091
—
-
-
.
320
1027
26653
22140
88.0
3.0
SEE TABLES
0.00504
0.00419
0.96
0.00102
0.00597
0.00495
1.13
0.00121
240
1010
27142
22502
88.0
3.3
2 -3
0.00727
0.00602
1.40
0.00139
0.00839
0.00695
1.62
0.00160
320
1011
26472
22331
85.7
2.9
0.00567
0.00473
1.07
0.00111
0.00718
0.00595
1.38
0.00140
(1) Based on throughput through primary crusher.
(2) Back-half sample for run number 1 was lost.
Reference 1.
A-17
-------
TABLE 2
FACILITY Al
Summary of Visible Emissidns
Date: 6/4/74 6/5/74
Type of Plant: Crushed Stone - Primary Crusher
Type of Discharge: Stack Distance from Observer to Discharge Point: 75 ft.
Location of Discharge: Baghouse Height of Observation Point: Ground-level
Height of Point of Discharge: 14 ft. Direction of Observer from Discharge Point: N.E.
Description of Background: Grey building
Description of Sky: Clear
Wind Direction: East Wind Velocity: 0-5 mi/hr.
Color of Plume: None Detached Plume: No
Duration of Observation: 6/4/74 78 minutes
6/5/74 - 210 minutes
SUMMARY OF AVERAGE OPACITY
(1)
Set Number
1 through 6
7 through 9
10 through 13
14 through 48
Start
8:50
11:23
12:12
8:11
Time
End
9:26
11:41
12:36
11:41
Sum
0
0
0
0
Opacity
Average
0
0
0
0
Readings were 0 percent opacity during all periods of observation.
Sketch Showing How Opacity Varied With Time: Not Available
Reference 1.
A-18
-------
FACILITY Al
SUMMARY OF VISIBLE EMISSIONS
(1)
Date: 7/8/75 - 7/9/75
Tyoe of Plant: Crushed stone (cement rock)
Type of Discharge: Fugitive
Location of Discharge: Primary Impact crusher (discharge conveyor or transfer point)
Height of Point of Discharge: 6 feet
Oescr1ot1on of Background: Grey wall
Description of Sky: N.A. (Indoors)
Wind Direction: N.A.
Color of Plume: White
Duration of Observation:
Distance from Observer to Discharge Point: 15 feet
Height of Observation Point: Ground level
Direction of Observer from Discharge Point: SE
Wind Velocity: No wind (indoors)
Detached Plume: No
Summary of Data:
Ooadty,
Percent
7/8/75 - 2 hours
7/9/75 - 2 hours
Total Time Equal to or
Greater Than Given Opacity
Min.Sec.
3
IT
0
0
0
30
30
15
15
0
5
10
15
20
25
30
35
40
45
50
Sketch Showing How Opacity Varied With Time:
Ooacltv,
Percent
55
60
65
70
75
80
85
90
95
100
Total Time Equal to or
Greater Than Given Ooacltv
MlnT
Sec.
g20
o
* -IP
o- 15
E 10
o
I 5
0
i
Not Available
—
__
—
1 A // A ' A
I i // 0 I 2
7/8/75
TIME, hours
7/9/75
(1) Two observers made simultaneous readings* the greater of their readings
1s reported.
Reference 2.
A-19
-------
Run Number
Date
TABLE 4
FACILITY A2
Sunmary of Results
1
6/10/74 6/11/74 6/12/74
) Throughput through primary crusher.
2) All three te^t runs were over-lsokinetic.
3) Back-half sample for run number 1 was lost.
Reference 1.
Average
Test Time - Minutes
Production Rate - TPH^
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature °F
Water vapor - Vol . X
Visible Emissions at
Collector Discharge -
% Opacity
Particulate Emissions '2'
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch <3)
gr/DSCF-
gr/ACF
Ib/hr
Ib/ton
400 320
965 1023
15797 15771
13368 13246
90.0 90.0
1.4 2.1
SEE TABLE
0.00176 0.00188
0.00149 0.00158
0.20 0.21
0.00021 0.00024
0.00235
0.00197
0.27
0.00030
240
1056
15866
13196
94.0
2.5
5
0.00222
0.00184
0.25
0.00024
0.00314
0.00261
0.36
0.00034
320
1015
15811
13270
91.3
2.0
0.00195
0.00164
0.22
0.00023
0.00275
0.00224
0.32
0.00032
A-20
-------
TABLE 5
FACILITY A2
Summary of Visible Emissions
Date: 6/10/74 - 6/11/74
Type of Plant: Crushed Stone - Primary Screen
Type of Discharge: Stack Distance from Observer to Discharge Point: 60 ft.
Location of Discharge: Baghouse Height of Observation Point: Ground-level
Height of Point of Discharge: 10 ft. Direction of Observer from Discharge Point: East
%
Description of Background: Sky
Description of Sky: Clear
Wind Direction: Southwest Wind Velocity: 0-2 mi/hr.
Color of Plume: None Detached Plume: No
Duration of Observation: 6/10/74 - 192 minutes
6/11/74 - 36 minutes
SUMMARY OF AVERAGE OPACITY^
Time
Set Number
1 through 11
12 through 32
33 through 38
Start
10:35
12:30
9:40
End
11:41
2:36
10:1*
Opacity
Sum
0
0
0
Average
0
0
0
Readings were 0 percent opacity during all periods of observation.
Sketch Showing How Opacity Varied With Time: Not Available
Reference 1.
A-21
-------
Run Number
Date
TABLE 6
FACILITY A3
Sutmnary of Results
1 2 3
6/10/74 6/11/74 6/12/74
(1) Back-half sample for run number 1 was lost.
Reference 1.
Average
Test Time - Minutes
Process Weight Rate - TPH
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature - °F
Water vapor - Vol. %
Visible Emissions at
Collector Discharge -
% Opacity
Parti cul ate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch*1*
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
360 288
910 915
2303 2313
*•
1900 1902
98.0 101.0
2.4 2.4
SEE TABLES
0.00095 0.00162
0.00078 0.00134
0.02 0.03
0.00002 0.00003
0.00190
0.00156
0.03
0.00003
288
873
2422
2003
97.0
2.3
7 and 8
0.00207
0.00171
0.04
0.00004
0.00259
0.00214
0.04
0.00005
312
899
2346
1935
98.7
2.4
0.00155
0.00128
0.03
0.00003
0.00224
0.00185
0.035
0.00004
A-22
-------
TABLE 7
FACILITY A3
Sunmary of Visible Emissions
Date: 6/11/74
Type of Plant: Crushed Stone - Conveyor Transfer Point
Type of Discharge: Stack Distance from Observer to Discharge Point: 60 ft.
Location of Discharge: Baghouse Height of Observation Point: Ground-level
Height of Point of Discharge: 8 ft. Direction of Observer from Discharge Point: North
Description of Background: Grey apparatus
Description of Sky: Clear
Wind Direction: Westerly Wind Velocity: 0-10 m1/hr.
Color of Plume: None Detached Plume: No
Duration of Observation: 240 minutes
SUMMARY OF AVEP.AGE OPACITY*1^
Time Goad ty
Set Number Start End Sum Average
1 through 30 10:40 1:40 0 0
31 through 40 1:45 2:45 0 0
Readings were 0 percent opacity during all periods of observation.
Sketch Showing How Opacity Varied With Time: Not Available
Reference 1.
A-23
-------
TABLE b
FACILITY A3
SUMMARY OF VISIBLE EMISSIONS
CD
Date: 7/9/7'j 7/10/75
Tyo* of Plant: Crushed stone (cement rock)
Type of Discharge: Fugitive
Location of Discharge: Conveyor (transfer point)
Height of Point of Discharge: 8 feet
Description of Background: Sky
Description of Sky: Partly cloudy
Wind Direction: South
Color of Plume: White
Distance from Observer to Discharge Point: 50 feet
Height of Observation Point: 6 feet
Direction of Observer from Discharge Point: SE
Wind Velocity: 3-5 mph
Detached Plume: Mo
Duration of Observation: 7/9/75 - 106 minutes
7/10/75 - 60 minutes
Summary of Data
Ooacity,
Percent
5
10
15
20
25
30
35
40
45
50
3
0"
0
0
-
-
-
-
-
-
Total Time Equal to or
Greater Than Given Opacity
Min.Sec.
0
45
30
0
Opacitv,
Percent
55
60
65
70
75
80
85
90
95
100
Total Time Equal to or
Greater Than Given Qoacitv
MTrT SeT!
Sketch Showing How Opacity Varied With Time:
Not Available
5 15
t_
O)
o.
10
o
OL
O
I
-H-
7/9/75
TIME, hours
7/10/75
(1) Two observers made simultaneous readings, the greater of their readings
1s reported.
Reference 2.
A-24
-------
TABLE 9
FACILITY A4
Surmary of Results
Run Number
Date
Test Time - Minutes
Production Rate - TPH
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature - °F
Water vapor - Vol . X
Visible Emissions at
Collector Discharge -
X Opacity
Particulate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Reference 1.
1
6/6/74
320
170
10579
9277
81.0
2.3
0.00036
0.00031
0.03
0.00017
0.00047
0.00041
0.04
0.00022
2 3
6/7/74 6/8/74
320 320
162 152
9971 11045
8711 9656
77.0 80.0
2.2 2.1
SEE TABLE. 10
0.00075 0.00074
0.00065 0.00065
0.06 0.06
0.00034 0.00041
0.00104
0.00095
0.08
0.00050
Avera<
-
320
163
10532
9214
79.3
2.2
0.00062
0.00054
0.05
0.00031
0.00678
0.00068
0.06
0.00034
A-25
-------
TABLE 10
FACILITY A4
Summary of Visible Emissions
Date: 6/6/74
Type of Plant: Crushed Stone - Secondary Crushing and Screening
Type of Discharge: Stack Distance from Observer to Discharge Point: 100 ft.
Location of Discharge: Baghouse Height of Observation Point: Ground-level
Height of Point of Discharge: 15 ft. nirectlnn nf Observer from Discharge Point: North
Description of Background: Sky
Description of Sky: Clear
Wind Direction: Variable Wind Velocity: 0 to 10 mi/hr.
Color of Plume: None Detached Plume: No
Duration of Observation: 240 minutes
SUMMARY OF AVERAGE OPACITY^1 *
Set Number
Time
Start End
Opacity
Sum Average
1 through 30 10:40 1:40 0 0
31 through 40 1:45 2:45 0 0
Readings v/ere 0 percent opacity during all periods of observation.
Sketch Showing How Opacity Varied With Time: Not Available
Reference 1.
A-26
-------
Run Number
Date
Test Time - Minutes
TABLE 11
FACILITY Bl
Sunwary of Results
1 2 3
10/29/74 10/30/74 10/30/74
(1)
Production Rate - TPH
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFH
Temperature - °F
Water vapor - Vol. X
Visible Emissions at
Collector Discharge -
% Opacity
Particulate Emissions
Probe and filter catch
gr/DSC.F
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
(1) Throughput through primary crusher.
Reference 3.
Average
180
324
5154
4998
70
1.80
0.009
0.012
0.402
0.0012
0.009
0.011
0.496
0.0015
120
359
6121
5896
76
1.87
SEE TABLE.
0.001
0.004
0.072
0.0002
0.001
0.003
0.180
0.0005
120
375
6078
5753
83
2.06
12
0.010
0.011
0.500
0.0013
0.010
0.011
0.553
0.0015
140
353
5784
5549
76.3
1.91
0.007
0.009
0.325
0.0007
0.007
0.008
0.408
0.0012
A-27
-------
TABLE 12
FACILITY Bl
Summary of Visible Emissions^ '
Udtc: 10/P9/74 10/30/74
Typ«- of HI ant.: f.nr.hfd Stone Primary Crusher
Ty^c of Diicfiar'jc: LldCk
Locdtion of Llischurgc: Daghouse
Height of Point of Discharge: 25 ft.
Description of Background: Grey quarry wall
Description of Sky: Clear to cloudy
Wind Direction: Northwesterly ... . .. . ., ... ....
J Wind Velocity: Not available
Color of Plume: White _. . . . _. ..
Detached Plume: No
Duration of Observation: 10/29/74 180 minutes
10/30/74 234 minutes
Distance from Ovserver to Discharge Point: M ft.
Height of Observation Point: Ground level
Direction of Observer from Discharge Point: West
SUMMARY OF AVERAGE OPACITY
SUMMARY OF AVERAGE OPACITY
Time
Set Number
10/2^/74
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
20
27
28
29
30
10/30/74
31
32
33
Start
10:30
10:36
10:42
10:48
10:54
11:00
11:06
11:12
11:18
11:24
11:30
11:36
11:42
l:lb
1:21
1:27
1:33
1:39
l:4b
l:bl
1:57
2:03
2:09
2:lb
2:21
2:27
2:33
2:39
2:4b
2:bl
9:05
9:11
9:17
End
10:36
10:42
10:48
10:54
11:00
11:06
11:12
11:18
11:24
11:30
11:36
11:42
11:48
1:21
1:27
1:33
1:39
1:45
1:51
1:57
2:03
2:U9
2:15
2:21
2:27
2:33
2:39
2:45
2:51
2:57
9:11
9:17
9:23
Opacity
Sum
10
20
25
15
15
5
lu
25
20
15
25
30
15
0
15
5
5
0
0
0
5
5
0
0
0
5
5
0
0
10
0
0
0
Average Set Number
0.4
0.8
1.0
0.6
0.6
0.2
0.4
1.0
0.8
0.6
1.0
1.2
0.6
0
0.6
0.2
0.2
0
0
0
0.2
0.2
0
0
0
0.2
0.2
0
0
0.4
0
0
0
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
Time
Start
9:23
9:29
9:35
9:41
9:47
9:53
9:59
10:05
10:11
10:17
10:28
10:34
10:40
10:58
11:04
11:10
11:24
11:30
1:02
1:08'
1:14
1:20
1:26
1:32
1:38
1:44
1:50
1:56
2:02
2:08
2:14
2:20
2:26
2:39
2:45
2:51
End
9:29
9:35
9:41
9:47
9:53
9:59
10:05
10:11
10:17
10:23
10:34
10:40
10:46
11:04
11:10
11:16
11:30
11:36
1:08
1:14
1:20
1:26
1:32
1:38
1:44
1:50
1:56
2:02
2:08
2:14
2:20
2:26
2:32
2:45
2:51
2:57
Opacity
Sum
0
5
10
0
0
5
0
0
0
0
0
10
5
0
5
10
0
0
0
0
0
10
0
5
0
0
0
5
0
5
5
0
0
0
5
0
Average
0
0.2
0.4
0
0
0.2
0
0
0
0
}
J.4
J.2
0
0.2
0.4
0
0
0
0
0
D.4
3
0.2
0
0
0
0.2
0
0.2
0.2
0
0
0
0.2
0
Reference 3.
(1) Highest of two observers
A-28
-------
Run Number
Date
TABLE 13
FACILITY B2
Summary of Results
1
10/31/74 10/31/74 11/11/74
Average
Test Time Minutes
Production Rate - TPH
Stack Effluent
Flow rate - ACFM
Flow rate DSCFM
Temperature - °F
Water vapor - Vol . %
Visible Emissions at
Collector Discharge -
% Opacity
Particulate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
108
270
19684
18296
92.0
1.95
0.003
0.003
0.427
0.0016
0.006
0.005
0.916
0.0034
108
270
18921
17638
96.0
1.92
SEE TABLES
0.005
0.005
0.753
0.0028
0.006
0.006
0.978
0.0036
108
270
16487
15681
79.0
2.01
14- 22
0.003
0.003
0.457
0.0017
0.007
0.007
0.955
0.0035
108
270
18197
17205
87.0
1.96
0.0037
0.0037
0.546
0.0020
0.0063
0.0060
0.946
0.0035
Reference 3
A-29
-------
TABLE 14
FACILITY B2
Summary of Visible Emissions (1)
Date: 10/31/74 - 11/1/74
Type of Plant: Crushed Stone - Secondary and Tertiary Crushing and Screening
Type of Discharge: Stack Distance from Observer to Discharge Point: 30 ft.
Location of Discharge: Baghouse Height of Observation Point: 5 ft.
Height of Point of Discharge: 8 ft. Direction of Observer from Discharge Point: East
Description of Background: Sky
Description of Sky: Clear to partly cloudy
Wind Direction: Southeasterly Wind Velocity: Not available
Color of Plume: White Detached Plume: No .
Duration of Observation: 10/31/74 -
240 minutes
11/1/74 -
106 minutes
SUMMARY OF AVERAGE OPACITY
Time Opacity
Date Set Number
10/31/74 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21 through
40
11/1/74 41 through
56
Start
9:27
9:33
9:39
9:45
9:51
9:57
10:03
10:09
10:15
10:21
10:27
10:33
10:39
10:45
10:51
10:57
11:03
11:09
11:15
11:21
1:09
8:11
End
9:33
9:39
9:45
9:51
9:57
10:03
10:09
10:15
10:21
10:27
10:33
10:39
10:45
10:51
10:57
11:03
11:09
11:15
11:21
11:27
3:09
9:47
Sum
5
10
5
0
5
5
10
5
20
0
0
0
5
5
10
0
5
0
0
10
0
0
Average
0.2
0.4
0.2
0
0.2
0.2
0.4
0.2
0.8
0
0
0
0.2
0.2
0.4
-o
0.2
0
0
0.4
0
0
Readings ranged from 0 to 5 percent opacity.
(1) Higher of two observers
Reference 3.
A-30
-------
Table 15
FACILITY 82
SUMMARY OF VISIBLE EMISSIONS
Date: 6/30/75
Tyoe of Plant: Crushed stone (limestone)
Type of Discharge: Fugitive
Location of Discharge: Secondary Cone Crusher (#1)
Height of Point of Discharge: 25 ft. Distance from Observer to Discharge Point:45 ft.
Descriotion of Background:Sky & Equipment Height of Observation Point: 2 ft.
Description of Sky: Clear Direction of Observer from Discharge Point:North
Mind Direction: East Wind Velocity: 5-10 mph
*
Color of Plume: White Detached Plume: No
Duration of Observation: 231 minutes
Summary of Data:
Ooacity,
Percent
5
10
15
20
25
30
35
40
45
50
Total Time Equal to
Greater Than Given
Min.
23
0
or
Opacity^
Sec.
0
45
Ooacitv, Total Time Equal to or
Percent Greater Than Given Onacitv
55
60
65
70
75
80
85
90
95
100
Min.
Sec.
Reference 4
A-31
-------
Table 16
FACILITY B2
SUMMARY OF VISIRLE EMISSIONS
Date: 6/30/75
Tyoe of Plant: Crushed stone (limestone)
Tyoe of Discharge: Fugitive
Location of Discharge: Secondary Cone Crusher
Hsin^t of Point of Discharge: 25 ft. Distance from Observer to Discharge Point: 45 ft.
Descriotion of Background: Sky & Equipment Heiaht of Observation Point: 2 ft.
Description of Skv: Clear Direction of Observer from Discharge Point: North
Wind Direction: East Wind Velocity: 5-10 mph
Color of Plume: White Detached Plume: No
Duration of Observation: 231 minutes
Summary of Data:
Ooacity,
Percent
5
10
15
20
25
30
35
40
45
50
Total Time Equal to or
Greater Than Given Opacity
Hin.Sec.
0
0
15
0
noacitv,
Percent
55
60
65
70
75
80
85
90
15
100
Total Time Equal to or
Greater Than Given Onacitv
Min.
Sec.
Reference 4
A-32
-------
Tab!o 17
FACILITY B2
SUMMARY OF VISIBLE EMISSIONS
Date: 6/30/75
Tyoe of Plant: Crushed stone (limestone)
Type of Discharge: Fugitive
Location of Discharge: Secondary Cone Crusher
Height of Point of Discharge: 25 ft. Distance from Observer to Discharge Point: 45 ft.
Oescriotion of Background: Sky & Equipment Height of Observation Point: 2 ft.
Oescriotion of Sky: Clear Direction of Observer from Discharge Point: North
Mind Direction: East Wind Velocity: 5-10 mph
Color of Plume: White Detached Plume: No
Duration of Observation: 231 minutes
Summary of Data:
Ooaclty,
Percent
Total Time Equal to or
Greater Than Given Opacity
RTrT Seel
5
10
15
20
25
30
35
40
45
50
Opacity, Total Time Equal to or
Percent Greater Than Given Onacitv
55
60
65
70
75
80
85
90
05
100
Min.
Sec.
Reference 4
A-33
-------
Tabln 18
FACILITY 82
SUMMARY OF VISIBLE EMISSIONS
Date: 6/30/75 - 7/1/75
Tvoe of Plant: Crushed stone (limestone)
Tyoe of Discharge: Fugitive
Location of Discharge:Surge Bin
Hei^t of Point of Discharge: Distance from Observer to Discharge Point: 150 ft.
Descriotion of Background:Sky & Equipment Height of Observation Point: 15 ft.
0-scrintion of Sky: Clear Direction of Observer from Discharge Point:SE
Wind Direction: south
Color of Plume: white
Wind Velocity: 5 mph
Detached Plume: No
Duration of Observation: 6/30/74 - 234 minutes
7/1/75 - 53 minutes
Summary of Data:
Ooacity,
Percent
5
10
15
20
25
30
35
40
45
50
Total Time Equal to
Greater Than Given
Min.
2
1
_
-
or
Opacity^
Sec.
0
15
30
-
Opacity,
Percent
55
60
65
70
75
80
85
90
05
100
Total Time Equal to or
Greater Than Given Onacitv
Mi n . Sec .
Reference 4
A-34
-------
Table 19
FACILITY B2
SUMMARY OF VISIBLE EMISSIONS
Date: 6/30/75 - 7/1/75
Tyoe of Plant: Crushed stone (limestone)
Type of Discharge: Fugitive
Location of Discharge: Scalp'ing screen
Height of Point of Discharge:50 ft. Distance from Observer to Discharge Point:150 ft.
Descriotion of Background:Sky & Equipment Height of Observation Point: 15 ft.
Description of Sky: Clear Direction of Observer from Discharge Point: SE
Wind Direction: South Wind Velocity: 5 MPH
Color of Plume: White Detached Plume: no
Duration of Observation: 6/30/75 - 234 minutes
7/1/75 - 53 minutes
Summary of Data:
Ooacity,
Percent
5
10
15
20
25
30
35
40
45
50
Total Time Equal to
Greater Than Given
Hin.
44
9
3
0
-
or
Opacity
Sec.
45
45
0
30
-
Opacity, Total Time Equal to or
Percent Greater Than Given Onacitv
Min. Sec.
55
60
65
70
75
80
85
90
95
100
Reference 4
A-35
-------
Table 20
FACILITY B2
SUMMARY OF VISIRLE EMISSIONS
Date: 6/30/75 - 7/1/75
Tvoe of Plant: Crushed stone (limestone)
Tyoe of Discharge: Fugitive
Location of Discharge: Hammenm'11
Height of Point of Discharge: Distance from Observer to Discharge Point: 150 ft.
Oescriotion of Background: Sky & Equipment Height of Observation Point: 15 ft.
Oescrintion of Sky: Clear Direction of Observer from Discharge Point:SE
Wind Direction: South Wind Velocity: 5 mph
Color of Plume: White Detached P]^..,e: No
Duration of Observation: 6/30/75 - 234 minutes
7/1/75 53 minutes
Summary of Data:
Ooaci ty,
Percent
5
10
15
20
25
30
35
40
45
50
Total Time Equal to
Greater Than Given
Min.
0
_
or
Opacity
Sec.
0
Ooacitv, Total Time Equal to or
Percent Greater Than Given Onacitv
55
60
65
70
75
80
85
90
%
TOO
Min.
Sec.
Reference 4
A-36
-------
FACILITY B2
SUMMARY OF VISIBLE EMISSIONS
Date: 7/1/75
Tyoe of Plant: Crushed stone (limestone)
Type of Discharge: Fugitive
Location of Discharge: (3-Deck) Finishing Screen (left)
of Point of Discharge: 40 '
Descriotion of Background: Hazy Sky
OescriDtion of Sky: Clear
Mind Direction: Southeast
Color of Plume: White
Duration of Observation: 107 minutes
Distance from Observer to Discharge Point:75 ft.
Heipht of Observation Point: Ground level
Direction of Observer from Discharge Point:West
Wind Velocity: 5-15 mph
Detached Plume: No
Summary of Data:
Ooacity,
Percent
5
10
15
20
25
30
35
40
45
50
Total Time Equal to or
Greater Than Given Opacity
Min. Sec.
4 30
Ooacitv,
Percent
55
60
65
70
75
80
85
90
95
100
Total Time Equal to or
Greater Than Given Ooacitv
Min.
Sec.
Reference 4
A-37
-------
Table 22
FACILITY B2
SUMMARY OF VISIBLE EMISSIONS
Date: 7/1/75
Tvoe of Plant: Crushed stone (limestone)
Tyoe of Discharge: Fugitive
Location of Discharge:(3-Deck) Finishing screen (right)
Hsiqht of Point of Discharge: 40 ft.
Oescriotion of Background: Hazy sky
Description of Sky: Clear
Wind Direction: Southeast
Color of Plume: .White
Duration of Observation: 107 minutes
Distance from Observer to Discharge Point: 75 ft.
Height of Observation Point: Ground level
Direction of Observer from Discharge Point: West
Wind Velocity: 5-15 mph
•
Detached Plume: No
Summary of Data:
Opacity,
Percent
Total Time Equal to or
Greater Than Given Opacity
Win.
5
11
15
20
25
30
35
40
45
50
Reference 4
Sec.
15
Opacity,
Percent
55
60
65
70
75
80
85
90
05
100
Total Time Equal to or
Greater Than Given Ooacitv
Min.
Sec.
A-38
-------
Run Number
Date
Test Time - Minutes
Production Rate - TPH
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature - °F
Water Vapor - Vol. %
Visible Emissions at
Collector Discharge -
% Opacity
Particulate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch*1*
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
TABLE ?-*
FACILITY 83
Summary of Results
1
10/31/74
270
11/1/74
270
3
11/1/74
270
Average
270
18674
17335
92
2.13
0.002
0.002
0.355
0.0013
18405
17186
90
1.73
0.004
0.004
0.614
0.0023
16238
15466
79
1.87
0.003
0.003
0.411
0.0015
17772
16662
87
1.91
0.003
0.003
0.460
0.0017
(1)
No analysis of bark-half on in-stack filter tests.
Reference 3.
A-39
-------
Run Number
Date
Test Time - Minutes
TABLE 2,4
FACILITY Cl
Summary of Results
1 2 3
11/19/74 11/21/74 11/22/74
(1)
120
Production Rate - TPH
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature - °F
Water vapor - Vol. X
Visible Emissions at
Collector Discharge -
I Opacity
Particulate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
(1) Throughput through primary crusher.
Reference 5.
240
240
Average
200
7340
7260
66.0
1.0
0.003
0.003
0.18
0.001
0.007
0.007
0.43
0.003
7560
7720
38.0
0.4
SEE TABLE
0.0007
0.0007
0.05
0.0004
0.001
0.001
0.09
0.0008
7520
7800
44.0
0.1
25
0.003
0.003
0.17
0.001
0.003
0.003
0.21
0.002
7473
7593
49.3
0.5
0.0012
0.0012
0.10
0.0008
' 0.0037
0.0037
0.24
0.0019
A-40
-------
TABLE 25
FACILITY Cl
Summary of Visible Emissions
(1)
Date: 11/21/74
Type of Plant: Crushed Stone - Primary and Secondary Crushing and Screening
Type of Discharge: Stack
Location of Discharge: Baghouse
Height of Point of Discharge: 40 ft.
Description of background: Dark Woods
Description of Sky: Overcast
Wind Direction: Easterly
Color of Plume: White
Duration of Observation: 240 minutes
Distance from Observer to Discharge Point: 100 ft.
Height of Observation Point: 50 ft.
Direction of Observer from Discharge Point: N.W.
Wind Velocity: 10 to 30 mi/hr.
Detached Plume: No
SUMMARY OF AVERAGE OPACITY
Time
(2)
Opacity
Set Number
Start
End
Sum
Average
1 througn 40 12:10 4:10 0
Readings were 0 percent opacity during the observation period.
Sketch Showing How Opacity Varied With Time:
5
01
(1)
3 4
Time, hours
Two observers made simultaneous readings.
Reference 5.
A-41
-------
Run Number
Date
TABLE 26
FACILITY C2
Summary of Results
1
11/19/74 11/21/74 11/22/74
Average
Test Time Minutes
(1)
Production Rate - TPH
Stack Effluent
Flow rate - ACFM
Flow rate DSCFM
Temperature - °F
Water vapor Vol. I
Visible Emissions at
Collector Discharge
X Opacity
Participate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
(1) Throughput through primary crusher.
Reference 5.
120
132
6220
6260
62.0
0.4
0.006
0.006
0.31
0.002
0.008
0.009
0.46
0.003
240
119
6870
6880
50.0
0.3
SEE TABLE
0.00003
0.00003
0.002
0.00002
0.0006
0.0007
0.04
0.0003
240
127
6540
6700
51.0
0.1
27
0.0004
0.004
0.02
0.0002
0.0009
0.001
0.05
0.0004
200
126
6543
6613
54.3
0.27
0.00214
0.00214
o.m
0.00074
0.0032
0.0057
0.18
0.0012
A-42
-------
TABLE 27
FACILITY C2
Sunaary of Visible Emissions
(1)
Date: 11/21/74
Type of Plant: Crushed Stone - Finishing Screens
Type of Discharge: Stack
Location of Discharge: Baghouse
Height of Point of Discharge: 40 ft.
Description of Background: Dark woods
Description of Sky: Overcast
Wind Direction: Easterly
Color of Plume: White
Duration of Observation: 240 minutes
Distance from Observer to Discharge Point: 200 ft.
Height of Observation Point: 50 ft.
Direction of Observer from Discharge Point: N.W.
Wind Velocity: 10 to 30 ml/hr.
Detached Plume:
SUmARY OF AVERAGE OPACITY
Time
Set Number
Opacity
Start
Sum
Average
1 through 40 12:10 4:10 0
Readings were 0 percent opacity during the observation period.
Sketch Showing How Opacity Varied With Time:
+»
I
Time, hours
0)
Two observers made simultaneous readings.
A-43
-------
Run Number
Date
TABLE 28
FACILITY 01
Surmary of Results
1 2 3
9/17/74 9/18/74 9/19/74
(1) Throughput through primary crusher.
Reference 6.
Average
Test Time - Minutes
Production Rate - TPhO^
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature - °F
Water vapor - Vol . %
Visible Emissions at
Collector Discharge -
I Opacity
Particulate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
240
225
31830
31370
66.0
1.2
0.0095
0.0094
2.55
0.0113
0.0100
0.0096
2.69
6.0120
240
230
31810
30650
71.0
1.7
SEE TABLES
0.0081
0.0078
2.13
0.0093
0.0085
0.0082
2.23
0.0097
240
220
31950
31230
68.0
1.6
29-35
0.0080
0.0078
2.13
0.0097
0.0086
0.0084
2.30
0.0105
240
225
31863
31083
68.3
1.5
0.0085
0.0083
2.27
0.0101
0.0090
0.0088
2.41
0.107
A-44
-------
TABLE 29
FACILITY 01
Summary of Visible Emissions
0)
Date: 9/17/74
Type of Plant: Crushed Stone - Secondary and Tertiary Crushing & Screening
Type of Discharge: Stack
Location of Discharge: Baghouse
Height of Point of Discharge: 55 ft.
Description of Background: Trees
Description of Sky: partly Cloudy
Wind Direction: Northerly
Color of Plume: None
Duration of Observation: 240 minutes
Distance from Observer to Discharge Point: 300 ft.
Height of Observation Point: 40 ft.
Direction of Observer from Discharge Point: S.E.
Hind Velocity: 5-10 m1/hr.
Detached Plume: No
(2)
Set Number
SUWARY OF AVERAGE OPACITY
Time Opacity
Slart
End
sum
Average
1 through 40 9:10 1:00 0 0
Readings were 0 percent opacity during the period of observation.
Sketch Showing How Opacity Varied With Time:
0)
o
I
3 4
Time, hours
* ' Two observers made simultaneous readings.
Reference 6.
A-45
-------
Tab!» 30.
FACILITY Dl
SUMMARY OF VISIBLE EMISSIONS
Date: 7/8/75
Tvoe of Plant: Crushed stone (traprock)
Tyoe of Discharge: Fugitive
Location of Discharge: Tertiary gyrasphere cone crusher (S)
Height of Point of Discharge:
Oescriotion of Background: Machinery
Oescriotion of Sky: Overcast
Wind Direction: Southwest
Color of Plume: white
Duration of Observation: 170 minutes
Distance from Observer to Discharge Point: 30 ft.
Height of Observation Point: ground level
Direction of Observer from Discharge Point: West
Wind Velocity: 0-10 mph
Detached Plume: No
Summary of Data:
Ooacity,
Percent
5
10
15
20
25
30
35
40
45
50
Total Time Equal to or
Greater Than Gi ven Opaci ty
Min.Sec.
Ooacitv,
Percent
55
60
65
70
75
80
85
90
95
100
Total Time Equal to or
Greater Than Given Opacity
Sec.
Reference 7
A-46
-------
Table 31
FACILITY 01
SUMMARY OF VISIBLE EMISSIONS
Date: 7/8/75
Tyoe of Plant: Crushed stone (traprock)
Type of Discharge: Fugitive
Location of Discharge: Tertfary gyrashere cone crusher (N)
Height of Point of Discharge:
Descrlotlon of Background: Machinery
Description of Sky: Overcast
Wind Direction: Southwest
Color of Plume: White
Duration of Observation: 170 minutes
Distance from Observer to Discharge Point: 30 ft.
Height of Observation Point: ground level
Direction of Observer from Discharge Point: West
Wind Velocity: 0-10 mph
Detached Plume: No
Summary of Data:
Ooaclty,
Percent
Total Time Equal to or
Greater Than Given Opaci ty
Min.Sec.
5
10
15
20
25
30
35
40
45
50
•Opacity, Total Time Equal to or
Percent Greater Than Given Ooacitv
55
60
65
70
75
80
85
90
95
100
Min.
Sec.
Reference 7
A-47
-------
Tab!ft 32
FACILITY Dl
SUMMARY OF VISIRLE EMISSIONS
Date: 7/8/75
Tvoe of Plant: Crushed stone (traprock)
Tyoe of Discharge: Fugitive
Location of Discharge: secondary standard cone crusher
Height of Point of Discharge:
Oescriotion of Background: Machinery
Description of Sky: Overcast
Wind Direction: Southwest
Color of Plume: White
Duration of Observation: 170 minutes
Distance from Observer to Discharge Point: 30 ft,
Height of Observation Point:Ground level
Direction of Observer from Discharge Point:West
Wind Velocity: 0-10 mph
Detached Plume: No
Summary of Data:
Ooacity,
Percent
Total Time Equal to or
Greater Than Given Opacity
Min.Sec.
5
10
15
20
25
30
35
40
45
50
Ooaci ty,
Percent
55
60
65
70
75
80
85
90
%
100
Total Time Equal to or
Greater Than Given Ooacitv
Min.
Sec.
Reference 7
A-48
-------
33
FACILITY Dl
SUMMARY OF VISIBLE EMISSIONS
Date: 7/9/75
Tvoe of Plant: Crushed stone (traprock)
Type of Discharge: Fugitive
Location of Discharge: Scalp'lng screen
Height of Point of Discharge:
Oescriotion of Background: Equipment
Description of Sky: Overcast
Wind Direction: Southwest
Color of Plume: white
Duration of Observation: 210 minutes
Summary of Data:
Ooaclty,
Percent
5
10
15
20
25
30
35
40
45
50
Distance from Observer to Discharge Point: 30 ft.
Height of Observation Point: 15 ft.
Direction of Observer from Discharge Point: North
Wind Velocitv: 0-10 mph
Detached Plume: No
Total Time Equal to or
Greater Than Given Opacity
RTiT SecT
Opacity,
Percent
55
60
65
70
75
80
85
90
05
100
Total Time Equal to or
Greater Than Given Onacitv
Min.
Sec.
ftefc
A-49
-------
Tab!* 34
FACILITY Dl
SUMMARY OF VISIBLE EMISSIONS
Date: 7/9/75
Tyoe of Plant: Crushed stone (traprock)
Tyoe of Discharge: Fugitive
Location of Discharge: Secondary (2-Deck) sizing screens
Height of Point of Discharge:
Description of Background: Equipment
Oescrintion of Sky:Overcast
Mind Direction: Southwest
Color of Plume: White
Duration of Observation: 210 minutes
Distance from Observer to Discharge Point: 30 ft.
Height of Observation Point: 15 ft.
Direction of Observer from Discharge Point: North
Wind Velocity: 0-10 mph
Detached Plume: No
Summary of Data:
Ooacity,
Percent
Total Time Equal to or
Greater Than Given Opacity
Min.Sec.
5
IT
15
20
25
30
35
40
45
50
Reference 7
0
Opacity, Total Time Equal to or
Percent Greater Than Given Onacitv
55
60
65
70
75
80
85
90
H5
100
Min.
Sec.
A-50
-------
35
FACILITY 01
SUMMARY OF VISIBLE EMISSIONS
Date: 7/9/75
Tvoe of Plant: Crushed stone (traprock)
Tyoe of Discharge: Fugitive
Location of Discharge: Secondary (3-Deck) sizing screens
Height of Point of Discharge:
Description of Background: Equipment
Description of Sky: Overcast
Wind Direction: Southwest
Color of Plume: White
Duration of Observation: 210 minutes
Distance from Observer to Discharge Point: 30 ft
Height of Observation Point: 15 ft.
Direction of Observer from Discharge Point: North
Wind Velocity: 0-10 mph
Detached Plume: No
Summary of Data:
Ooacity,
Percent
Total Time Equal to or
Greater Than Given Opacity
Min.Sec.
5
10
15
20
25
30
35
40
45
50
Ooacitv, Total Time Equal to or
Percent Greater Than Given Ooacitv
55
60
65
70
75
80
85
90
05
TOO
Min.
Sec.
Reference 7
A-51
-------
Run Number
Date
TABLE .36
FACILITY 02
Seminary of Results
1 2 3
9/17/74 9/18/74 9/19/74
(1) Throughput through primary crusher.
Reference 6.
Average
Test Time - Minutes
Production Rate - TPH^
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature °F
Water vapor - Vol . X
Visible Emissions at
Collector Discharge -
X Opacity
Participate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
240
225
26790
26200
69.0
1.3
0.0027
0.0027
0.61
0.0027
0.0041
0.0040
0.91
0.0040
240
230
26260
25230
74.0
1.6
SEE TABLES
0.0038
0.0036
0.82
0.0036
0.0045
0.0043
0.98
0.0043
240
220
24830
24170
72.0
1.3
37 and 33
0.0023
0.0022
0.47
0.0021
0.0031
0.0030
0.64
0.0029
240
225
25960
25200
71.7
1.4
0.0029
0.0028
0.63
0.0028
0.0039
0.0038
0.84
0.0037
A-52
-------
TABLE 37
FACILITY D2
Summary of Visible Emissions
(1)
Date: 9/18/74
Type of Plant: Crushed Stone - Finishing Screens
Type of Discharge: Stack
Location of Discharge: Baghouse
Height of Point of Discharge: 55 ft.
Description of Background: Trees
Description of Sky: Clear
U1nd Direction: Northerly
Color of Plume: None
Duration of Observation: 240 minutes
Distance from Observer to Discharge Point: 300 ft
Height of Observation Point: 40 ft.
Direction of Observer from Discharge Point: North
Mind Velocity: 5 to 10 m1/hr.
Detached Plume: No
SUMMARY OF AVERAGE OPACITY
Time
Opacity
Set Number
Start
Tnd
Sum
Average
1 through 40 8:30 12:30 0
Readings were 0 percent opacity during period of observation.
Sketch Showing How Opacity Varied with Time:
Tine, hours
(1)
Two observers made simultaneous readings.
Reference 6.
A-53
-------
TABLE J0
FACILITY D2
SUMMARY OF VISIBLE EMISSIONS
Date: 7/10/75-7/11/75
Tyoe of Plant: Crushed stone (Traprock)
Type of Discharge: Fugitive
Location of Discharge: Finishing screen
Height of Point of Discharge: 30-50 ft.
Oescriotlon of Background: Equipment
Description of Sky: Partly cloudy
Wind Direction: Southwest
Color of Plume: White
Distance from Observer to Olscharge Point: 75 ft.
Height of Observation Point: Ground level
Direction of Observer from Discharge Point:Southwest
Wind Velocity: 0-5 mph
Detached Plume: No
Duration of Observation: 7/10/75 - observer 1 (94 minutes) - observer 2 (110 minutes)
7/11/75 observer 1 (70 minutes) - observer 2 (100 minutes)
Total Time Equal to or
Greater Than Given Opacity
Sec.
Summary of Data:
Ooaclty,
Percent
5
10
15
20
25
30
35
40
45
50
Sketch Showing How Opacity Varied With Time:
Ooacitv,
Percent
55
60
65
70
75
80
85
90
95
100
Total Time Equal to or
Greater Than Given Opacity
0)
u
4)
0.
CL.
o
(7/10/75)
2 0 1
TIME, hours
(7/11/75}
(1) Two observers made simultaneous readings.
Reference 7.
A-54
-------
Run Number
Date
TABLE 39
FACILITY El
Summary of Results
1 2 3
11/18/74 11/18/74 11/19/74
Average
Test Time - Minutes
Production Rate - TPH^
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature - °F
Water vapor - Vol. %
Visible Emissions at
Collector Discharge -
% Opacity
Particulate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
120
384
15272
16297
33.1
0.5
0.0134
0.0143
1.87
0.0049
0.0170
0.0181
2.37
0.0067
120
342
13997
14796
40.4
0.0
SEE TABLE
0.0116
0.0122
1.47
0.0043
0.0137
0.0145
1.74
0.0051
120
460
14975
15642
41.0
0.5
40
0.0147
0.0154
1.97
0.0043
0.0164
0.0171
2.20
0.0048
120
395
14748
15578
38.2
0.3
0.0132
0.0140
1.77
0.0045
0.0157
0.0166
2.10
0.0055
(1) Throughput through primary crusher.
Reference 8.
A-55
-------
TABLE 40
FACILITY El
Summary of Visible Emissions
(1)
Date: 11/18/74 11/19/74
Type of Plant: Crushed Stone - Tertiary Crushing and Screening
Type of Discharge: Stack
Location of Discharge: Bagnouse
Height of Point of Discharge: 1/2 ft.
Description of Background: Grey Mall
Description of Sky: Overcast
Wind Direction: Westerly
Color of Plume: None
Distance from Observer to Discharge Point: 60 ft.
Height of Observation Point: Ground level
Direction of Observer from Discharge Point: South
Wind Velocity: 2-10 m1/hr.
Detached Plume: No
Duration of Observation: 11/18/74 - 120 minutes
11/19/74 60 minutes
SUMMARY OF AVERAGE OPACITY
Time
Opacity
Set Number
11/18/74
1 through 10
11 through 20
Start
9:00
10:15
End
10:00
11:15
Sum
0
0
Average
0
0
11/19/74
21 through 30
10:07
11:07
Readings were 0 percent opacity during all periods of observation.
Sketch Showing How Opacity Varied With Time:
(1)
1
11/I8/74
1
11/19/74
Two observers made simultaneous readings.
Reference 8.
A-56
-------
TABLE 4i
FACILITY E2
Surmary of Results
Run Number
Date
1
11/18/74 11/18/74 11/19/74
Average
Test Time - Minutes
(1)
Production Rate - TPH
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFM
Temperature - °F
Water vapor - Vol. %
Visible Emissions at
Collector Discharge -
% Opacity
Particulate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/ton
(1) Throughput through primary crusher.
Reference 8.
120
384
22169
23001
44.5
1.1
0.0132
0.0137
2.60
0.0068
0.0205
0.0213
4.05
0.0105
120
342
19772
19930
59.2
1.1
SEE TABLE
0.0096
0.0097
1.65
0.0048
0.1378
0.0139
2.35
0.0069
120
460
21426
21779
55.0
0.6
42
0.0153
0.0155
2.85
0.0062
0.0170
0.0173
3.18
0.0069
120
395
21122
21570
52.9
0.9
0.0127
0.0130
2.37
0.0059
0.0171
0.0175
3.19
0.0081
A-57
-------
TABLE 42
FACILITY E2
Summary of Visible Emissions
Date: 11/18/74 11/19/74
Type of Plant: Crushed Stone - Finishing Screens and Bins
(D
Type of Discharge: Stack
Location of uischarge: Baghouse
Height of Point of Discharge: 1/2 ft.
Description of Background: Hillside
Description of Sky: Clear
Wind Direction: Westerly
Color of Plume: None
Distance from Observer to Discharge Point: 120 ft
Height of Observation Point: Ground level
Direction of Observer from Discharge Point: South
Wind Velocity: 2-10 mi/hr.
Detached Plume: No
Duration of Observation: 11/18/74 - 120 minutes
11/19/74 - 60 minutes
SUKHARY OF AVERAGE OPACITY
(2)
Time
Set Number
11/18/74
1 through 10
11 through 20
Start
12:50
1:50
End
1:50
2:00
Opacity
Sum
0
0
Average
0
0
11/19/74
21 through 30
9:05
10:05
Readings were 0 percent opacity during all periods of observation.
Sketch Showing How Opacity Varied With Time:
I It
11/18/74
Two observers made simultaneous readings.
Reference 8.
(1)
11/19/74
A-58
-------
TABLE 43
FACILITY F
Summary of Results
1
11/4/74 11/5/74 11/6/74
165
29.1
180
26.7
155
31.0
SEE TABLES 44-45
Average
166
28.9
687
659
71.0
0.98
661
655
60.0
0.61
643
636
64.0
0.71
663
650
65.0
0.77
Run Number
Date
Test Time - Minutes
Drilling Rate - ft/hr
Stack Effluent
Flow rate - ACFM
Flow rate - DSCFH
Temperature - °F
Water vapor - Vol. %
Visible Emissions at
Collector Discharge -
% Opacity
Particulate Emissions
Probe and filter catch
gr/DSCF
gr/ACF
Ib/hr
Ib/CF of hole
Total catch
gr/DSCF
gr/ACF
Ib/hr
Ib/CF of hole
(1) Based on hole depth of 80 feet and hole diameter of 5 Inches (0.136 ft2),
Reference 10.
0.032
0.030
0.179
0.045
0.033
0.032
0.189
0.048
0.031
0.031
0.176
0.048
0.033
0.032
0.183
0.050
0.055
0.054
0.298
0.071
0.057
0.056
0.308
0.073
0.039
0.038
0.218
0.055
0.041
0.040
0.227
0.057
A-59
-------
FACILITY F
Summary of Visible Emissions
Date: 11/4/74 - 11/6/74
Type of Plant: Crushed Stone - Drill
Type of Discharge: Stack
Location of Discharge: Baghouse
Height of Point of Discharge: 10 ft.
Description of Background: Quarry wall
Description of Sky: Partly cloudy
Wind Direction: Variable
Color of Plume: White
Distance from Observer to Discharge Point: 10 ft.
Height of Observation Point: 6 ft.
Direction of Observer from Discharge Point: West
Wind Velocity: 0-10 mi/hr.
Detached Plume: No
Duration of Observation: 11/4/74 - 84 minutes
11/5/74 - 252 minutes
11/6/74 - 156 minutes
SUMMARY OF AVERAGE OPACITY
Time
Date
11/4/74
11/5/74
11/6/74
Set Number
1 through
6
7 through
15
16 through
21
22 through
28
29 through
35
36 through
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58 through
63
64 through
70
71 through
76
77 through
83
Start
11:41
12:20
8:07
8:50
10:14
10:59
11:29
11:35
11:41
11:52
12:04
12:10
12:16
12:22
12:28
12:34
12:39
12:45
12:51
12:57
1:03
1:09
1:15
7:59
8:39
9:28
10:11
End
12:11
1:14
8:43
9:32
10:56
11:29
11:35
11:41
11:47
11:58
12:10
12:16
12:22
12:28
12:34
12:40
12:45
12:51
12:57
1:03
1:09
1:15
1:21
8:35
9:21
10:04
10:53
Opacity
Sum
0
0
0
0
0
0
5
25
45
0
30
30
55
15
55
95
5
70
65
75
65
95
75
0
0
0
0
Average
0
0
0
0
0
0
0.2
1.0
1.9
0
1.2
1.2
2.3
0.6
2.3
4.0
0.2
2.9
2.7
3.1
2.7
4.0
3.1
0
0
0
0
Readings ranged between 0 and 5 percent opacity during periods of observation.
Reference q
A-60
-------
TABLE 45
FACILITY F
SUMMARY OF VISIBLE EMISSIONS
(1)
Date: 7/2/75
Tyoe of Plant: Crushed stone
Type of Discharge: Fugitive
Location of Discharge: Drill (Rotary)
Height of Point of Discharge: 2 feet
Description of Background: Quarry wall
Description of Sky: Clear
Wind Direction: South
Color of Plume: White
Duration of Observation:
Distance from Observer to Discharge Point: 15 fee
Height of Observation Point: Ground level
Direction of Observer from Discharge Point: SE
Wind Velocity: 0 - 5 mph
Detached Plume: No
164 minutes
Summary of Data:
.(2)
Ooacity. Total Time Equal to or
Percent Greater Than Given
Min.
5 152
10 140
15 103
20 38
25 3
30 0
35 0
40
45
50
Sketch Showing How Opacity Varied Wi
3°._Hot Available
£25_
u
* 20-
o.
>-* m -
£ l*
>— «
£ 10-
ex.
o
5 -
0 -
I
0 1
Opacity
Sec.
0
45
30
45
15
15
0
-
-
•
th Time:
TIME,
Ooacitv. Total Time Equal to or
Percent Greater Than Given Onacit/
Min. Sec.
55
60
65
70 -
75 -
80 -
85 -
90
95 -
100
1 |
2 3
hours
(1)
Two observers made simultaneous readings, the greater of their readings is reported.
(2)
Refer nee 4
i::n^%-rn°L^^-^^^0is^^^^%^n?sirou^i?-.---
A-61
-------
TABLE 46
Facility G
Visible Emissions Data
Method 22
Percent of Time Emissions
Exceeded "X" Percent Opacity
Test Point
Primary Jaw
Crusher
Scalping Screen
Impact Crusher
Final screen
Secondary Cone
Crusher
Transfer Point
Date
10/2/79
10/3/79
10/4/79
10/3/79
10/2/79
10/3/79
Observation
Time (min)
20
40
60
20
40
60
120
60
"X"
0
10
15
0
15
0
10
0
Observer
1
69
26
67
78
12
0
76
1
2
59
44
69
96
41
0
61
1
Reference 10
A-62
-------
TABLE 47
Facility G
Summary of Visible Emissions
Method 9
Test Point
Date
Observation
Time (min)
Percent of Time Emissions
Greater than Given Ooacity
Opacity Observer
'(%) 1 2
Primary Jaw
Crusher 10/2/79 100
Scalping
Screen 10/3/79 60
Impact
Crusher 10/4/79 60
Final Screens 10/3/79 60
Secondary
Cone Crusher 10/2/79 120
Transfer
Point 10/3/79 60
0
5
10
15
20
25
30
35
40
0
5
10
15
20
0
5
10
15
20
0
5
0
5
10
15
20
25
30
35
0
5
10
15
20
25
89
72
32
11
3
< 1
< 1
0
100
82
19
1
0
100
99
29
0
1
0
93
44
11
2
< 1
0
3
1
1
1
1
0
89
68
35
21
12
5
1
< 1
0
100
79
15
1
0
100
74
17
1
0
0
85
72
58
32
14
4
< 1
0
--
--
- -
-_
-_
-_
Reference 10
A-63
-------
TABLE 48
Facility G
Summary of Visible Emissions
Method - Six Minute Averages
Date: 10/2/79 - 10/3/79
Primary
Crusher
Set Observer
Number 1 2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
9
7
14
14
13
14
12
—
7
9
2
5
15
10
10
10
10
13
1
6
15
11
13
9
10
14
10
15
18
21
8
10
11
5
Impact
Crusher Impact
Screen Crusher
Observer Observer
1212
10 11 15 10
8 10 11 7
9 8 11 7
8 9 11 9
8 10 11 10
12 9 10 8
13 9 10 13
12 10 11 13
10 10 13 10
10 11 11 9
Final Cone
Screen Crusher
Observer Observer
1212
004
005
008
0 0 11
009
0 0 10
009
007
0 0 10
008
8
13
7
8
8
1
0
0
0
1
11
18
22
25
23
17
16
15
15
16
15
21
13
13
15
4
1
1
1
4
Transfer
Point
Observer
1 2
3
0
0
0
0
0
0
0
0
0
Reference 10
A-64
-------
TABLE 49
Facility H
Visible Emissions Data
Method 22
Observation
Test Point Date Time (Min. )
Primary Jaw
Crusher 10/11/79
Scalping
Screen 10/11/79
Secondary
Screen 10/8/79
Secondary
Cone Crusher 10/8/79
10/10/79
30.
60
32
120
30
21
Percent of Time Emissions
Exceeded "X" Percent Opacit
Observer
"X" 1 2
0 27
10 8
0 0
0 0
0 93
15 87
27
5
7
0
95
72
Final
Screens
10/8/79
120
Reference 10
A-65
-------
TABLE 50
Facility H
Summary of Visible Emissions
Method 9
Test Point
Date
Observation
Time (Min.)
Opacity
Percent of Time Emissions
Greater than Given Opacity
Observer
1 2
Primary Jaw
Crusher 10/11/79 90
Scalping
Screen 10/11/79 32
Secondary
Screen 10/8/79 120
Secondary
Cone Crusher 10/8/79 51
& 10/10/79
Final
Screen 10/8/79 120
0
5
10
15
20
25
30
35
0
5
0
5
0
5
10
15
20
25
0
5
23
9
3
1
< 1
0
21
0
0
95
95
87
45
8
0
0
73
26
13
3
2
< 1
< 1
0
--
—
18
0
96
95
87
58
12
0
< 1
0
Reference 10
A-66
-------
TABLE 51
Facility H
Summary of Visible Emissions
Method 9 - Six Minute Averages
Date: 10/8/79 - 10/11/79
Primary
Crusher
Set
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
* Four
** Five
Observer
1
11
11
6
12
12
3
2
1
2
1
1
1
2
3
3
3
2
2
1
1
minute
minute
2
11
14
8
18
17
5
9
4
8
6
6
7
8
8
10
6
6
5
2
3
Initial
Screens
Observer
1
1
0
0
0
1
0
2
0
1
2
1
1
1
1
0
0
0
0
0
0
2
3
3
2
3
5
10
8
6
9
7
5
3
4
2
1
1
1
2
2
2
Transfer
Point
Observer
1
0
0
1
2
1
10
9
8
11
8
10
10
14
13
12
11
12
12
14
13
2
0
1
1
2
1
12
10
8
9
9
7
7
10
8
9
9
10
9
10
10
Secondary
Screens
Observer
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
1
1
2
2
1
1
1
1
0
0
0
Cone Final
Crusher Screens
Observer Observer
1
15
18
18
17
10
15
19
20
23
24
28
26
28*
25
28
29
27**
27
29
26
25**
2 1
4 0
17 0
19 0
18 0
12 0
18 0
19 0
21 0
23 0
23 0
24 0
26 0
28* 0
23 0
28 0
26 0
26**0
27 0
34 0
38 0
39**
2
0
0
0
0
0
< 1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
average
average
Reference 10
A-67
-------
Table 52
Facility I
Visible Emissions Data
Method 22
Test Point
Scalping
Screens
Primary
Jaw Crusher
Conveyor
Transfer Point
Secondary
Screen
Secondary
Cone Crusher
Final
Screens
Transfer
Point
Transfer
Point
Date
10/12/79
10/15/79
10/15/79
10/16/79
10/16/79
10/15/79
10/15/79
10/15/79
10/16/79
Observation
Time (Min.)
90
30
30
90
30
30
90
20
30
90
120
60
60
"X"
0
0
0
15
0
10
0
10
0
15
0
0
0
Percent
Exceeded
1
2
2
93
31
5
3
4
3
93
7
0
0
2
of Time Emissions
"X" Percent Opacity
Observer
2
2
4
92
33
12
30
9
12
99
< 1
0
0
2
Reference 10
A-68
-------
TABLE 53
Facility I
Summary of Visible Emissions
Method 9
Test Point
Date
Observation
Time (Min.)
Opacity
'
Percent of Time Emissions
Greater Than Given Opacity
Observer
Scalping
Screen
Primary
Jaw Crusher
Transfer
Point
Secondary
Screen
Secondary
Cone Crusher
Final
Screens
Transfer
Point
Transfer
Point
10/12/79 90
10/15/79 120
10/16/79 60
10/16/79 110
10/15/79 120
10/15/79 120
10/15/79 60
10/16/79 60
0
5
10
0
5
10
15
20
25
30
0
5
0
5
0
5
10
15
20
0
5
0
0
5
10
15
20
21
0
92
70
38
21
10
2
0
27
0
10
0
99
83
29
3
0
1
0
0
4
1
< 1
0
6
1
0
95
86
48
15
0
42
1
16
0
100
97
64
18
0
< 1
0
0
4
2
1
< 1
0
Reference 10
A-69
-------
TABLE 54
Facility I
Summary of Visible Emissions
Method 9 - Six Minute Averages
Date: 10/12/79 - 10/16/79
Initial
Screens
Observer
Run
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
< 1
0
2
1
3
1
1
1
1
1
3
1
< 1
< 1
< 1
0
0
0
2
2
2
0
0
0
< 1
1
< 1
0
0
< 1
1
< 1
0
< 1
1
< 1
0
0
0
0
0
Primary Transfer Secondary
Crusher Point Screens
Observer Observer Observer
1
14
16
16
16
12
9
13
9
13
12
17
9
14
13
15
8
6
6
10
9
2 1
13 0
14 0
14 2
9 <1
13 0
15 1
14 2
14 <1
15 3
13 4
16
13
11
12
13
9
6
9
11
12
2 1
0 0
1 < 1
1 < 1
< 1 0
0 0
3 0
4 0
3 0
4 0
5 0
0
< 1
4
5
0
0
0
0
0
0
2
0
3
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Cone
Crusher
Observer
1
< 1
9
9
12
13
11
13
12
13
14
12
10
9
7
8
12
13
11
11
12
2
8
14
17
15
15
15
16
14
16
14
17
17
17
10
15
10
11
11
11
11
Final Transfer
Screens Point
Observer Observer
1
0
0
<1
1
0
0
0
0
0
0
0
<1
0
0
<1
0
0
0
0
0
2
0
0
0
< 1
0
0
0
0
0
0
0
0
0
0
0
0 <
0 <
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
0
1
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
3
Reference 10
A-70
-------
TABLE 55
Facility J
Visible Emissions Data
Method 22
Test Point
Primary Jaw
Crusher
Scalping
Screen
Secondary
Cone Crusher
Secondary
Screen
Tertiary
Cone Crusher
Transfer
Point
Transfer
Point
Date
10/25/79
10/24/29
10/22/79
10/22/79
10/22/79
10/23/79
10/25/79
Percent of Time Emissions
Exceeded "X" Percent Opacity
Observation Observer
Time (Min.) "X" 1 2
60
60
120
30
30
60
45
75
30
30
62
120
120
0
10
0
0
10
15
0
0
0
10
15
0
0
3
0
0
68
8
5
1
1
11
37
13
0
0
5
0
0
49
14
1
11
6
25
36
11
< 1
0
Reference
10
A-71
-------
TABLE 56
Facility J
Summary of Visible Emissions
Method 9
Test Point
Primary
Jaw Crusher
Scalping
Screen
4.5' Cone
Crusher
Secondary
Screen
5.5' Cone
Crusher
Transfer
Point
&
Transfer
Point
Observer
Date Time (Min.)
10/25/79 120
10/24/79 120
10/23/79 120
10/22/79 125
10/22/79 122
10/23/79 120
10/24/79
10/25/79 120
Percent of Time Emissions
Greater Than Given Opacity
Opacity Observer
(7.) 1 2
0
5
10
15
0
0
5
10
0
5
10
0
5
10
15
0
5
0
5
21
< 1
0
0
72
5
0
8
0
86
62
18
0
< 1
0
1
0
21
8
< 1
0
0
55
1
0
10
< 1
0
90
70
11
0
< 1
0
0
Reference 10
A-72
-------
TABLE 57
Summary of Visible Emissions
Method 9 - Six Minute Averages
Date: 10/22/79 - 10/25/79
Run
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Primary
Crusher
Observer
1 2
3
1
1
1
1
1
1
1
0
1
1
0
0
0
2
1
3
3
2
0
1
2
1
0
1
3
1
1
2
2
1
0
0
1
2
0
2
3
1
1
Initial
Screens
Observer
1 2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4%' Cone
Crusher
Observer
1 2
3
4
4
2
4
6
6
3
2
5
4
5
3
5
5
5
3
3
3
1
3
4
5
3
3
4
4
2
2
3
3
5
2
4
3
2
0
2
1
2
Secondary
Screens
Observer
1 2
4
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5% ' Cone
Crusher
Observer
1 2
2
0
3
5
4
6
11
10
11
13
11
11
12
8
10
12
5
6
5
5
0
2
5
5
4
9
9
10
10
10
11
10
15
9
12
12
10
9
11
9
Transfer
Point
Observer
1 2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Transfer
Point
Observer
1 2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Reference 10
A-73
-------
TABLE 58
Facility K
Visible Emissions Data
Method 22
Test Point
Date
Observation
Time (Min.)
Percent of Time Emissions
Exceeded "X" Percent Opacity
Observer
1 2
Primary
Jaw Crusher
Transfer
Point
Scalping
Screen
Secondary
Cone Crusher
Storage
Bin
10/26/79
10/26/79
10/29/79
10/29/79
10/30/79
10/29/79
10/30/79
10/29/79
10/30/79
30
60
30
90
30
90
30
30
30
60
60
60
0
10
15
0
0
0
0
0
15
20
0
0
65
9
1
2
2
0
0
100
49
10
0
0
58
11
2
1
0
0
0
100
64
5
0
0
Reference 10
A-74
-------
TABLE 59
Facility K
Summary of Visible Emissions
Method 9
Test Point
Date
Observation
Time (Min . )
Opacity
& 10/30/79
Secondary
Cone Crusher 10/29/79
& 10/30/79
120
Storage
Bin
10/29/79
& 10/30/79
120
0
5
10
15
20
25
30
35
0
5
"Percent of Time Emissions
Greater Than Given Opacity
Observer
1 2
Primary
Jaw Crusher
Transfer
Point
&
Scalping
Screen
10/26/79 120
10/26/79 123
10/29/79
10/29/79 120
0
5
10
15
20
25
30
35
0
5
0
86
43
18
8
4
2
1
0
< 1
0
0
80
33
9
3
< 1
0
0
0
95
84
50
17
5
0
97
88
74
54
21
1
< 1
0
< 1
0
Reference 10
A-75
-------
TABLE 60
Facility K
Summary of Visible Emissions
Method 9 - Six Minute Averages
Date: 10/26/79 - 10/30/79
Run
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Primary
Crusher
Observer
1 2
4
6
8
3
5
10
4
5
11
7
8
8
8
9
10
8
10
9
10
6
4
7
8
3
5
8
3
5
7
7
4
8
6
8
6
8
5
4
6
5
Transfer
Point
Observer
1 2
0
0
0
0
0
0
4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Initial
Screens
Observer
1 2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Cone
Crusher
Observer
1 2
17
21
22
23
19
17
20
15
16
16
6
9
18
17
19
18
15
13
18
18
15
14
16
15
17
11
13
8
8
9
6
7
15
16
16
15
14
13
16
14
Storage
Bin
Observer
1 2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
2
0
0
0
2
0
Reference 10
A-76
-------
REFERENCES FOR APPENDIX A
1. Air Pollution Emission Test Report for Plant A, prepared jointly by EPA
and Valentine, Fisher and Tomlinson Consulting Engineers, Contract No.
68-02-0236, Task 16, EPA Report No. 74-STN-l.
2. Davis, John, Trip Report of Visible Emission Tests at Plant A, July 22.,
1975.
3. Air Pollution Emission Test Report for Plant B, prepared for EPA by
Engineering-Science Incorporated, Contract No. 68-02-1406, Task 7,
EPA Project Report No. 75-STN-3.
4. Brown, John W., Trip Report of Visible Emission Tests at Plants B and F,
July 14, 1975.
5. Air Pollution Emission Test Report for Plant C, prepared for EPA by
George D. Clayton and Associates, Contract No. 68-02-1408, Task 6,
EPA Report No. 75-STN-7.
6. Source Testing Report for Plant D, prepared for EPA by Roy F. Weston
Incorporated, Contract No. 68-02-0240, Task 10, EPA Report No. 75-STN-2.
7. Burbank, Jason J., Trip Report of Visible Emission Tests at Plant D,
July 23, 1975.
8. Air Pollution Emission Test Report for Plant E, prepared for EPA by
York Research Corporation, Contract No. 68-02-1401, Task 9, EPA Report
No. 75-STN-6.
9. Air Pollution Emission Test Report for Plant F, prepared for EPA by
Engineering-Science Incorporated, Contract No. 68-02-1406, Task 7,
EPA Report No. 75-STN-4.
10. Air Pollution Emission Test Report for Plants 6, H, I, J and K, prepared
for EPA by Scott Environmental Services, Contract No. 68-02-2813, Tasks
39 and 40, January, 1980.
»
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APPENDIX B
METHOD 22--VISUAL DETERMINATION OF FUGITIVE
EMISSIONS FROM MATERIAL PROCESSING SOURCES
1. Introduction
This method involves the visual determination of fugitive
emissions; i.e., emissions not emitted directly from a process stack or
duct. Fugitive emissions include emissions that (1) escape capture by
process equipment exhaust hoods, (2) are emitted during material
transfer, (3) are emitted from buildings housing material processing
or handling equipment, and (4) are emitted directly from process
equipment.
This method determines the amount of time that any visible
emissions occur during the observation period, i.e., the accumulated
emission time. This method does not require that the opacity of
emissions be determined. Since this procedure requires only the
determination of whether a visible emission occurs and does not require
the determination of opacity levels, observer certification
according to the procedures of Reference Test Method 9 are not required.
However, it is necessary that the observer is educated on the general
procedures for determining the level of visible emissions. As a
minimum the observer should be trained regarding the effects on the
visibility of emissions caused by background contrast, ambient lighting,
observer position relative to lighting, and the presence of uncombined
water (condensing water vapor).
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2. Applicability and Principle
2.1 Applicability. This method applies to the determination
of the frequency of fugitive emissions from stationary sources
(located indoors or outdoors) when specified as the test method for
determining compliance with new source performance standards.
2.2 Principle. Fugitive emissions produced during material
processing, handling, and transfer operations are visibly determined
by an observer without the aid of instruments. ;
3. Definitions
3.1 Emission Frequency. Percentage of time that emissions
are visible during the observation period.
3.2 Emission Time. Accumulated amount of time that emissions
are visible during the observation period.
3.3 Fugitive Emission. Pollutant generated by an affected
facility that is not collected by a capture system and is released
to the atmosphere.
3.4 Observation Period. Accumulated time period during which
observations are conducted, not to be less than 6 minutes.
4. Equipment
4.1 Stopwatches, accumulative type, with a sweep second hand
and unit divisions of at least 0.5 second; two required.
4.2 Light Meter. Light meter capable of measuring illuminance
in the 50- to 200-1ux range; required for indoor observations only.
5. Procedure
5.1 Position. Survey the affected facility or building or
structure housing the process unit to be observed, and determine the
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locations of potential emissions. If the affected facility is located
inside a building, determine an observation location that is consistent
with the requirements of the applicable regulation (i.e., outside
observation of emissions escaping the building/structure or inside
observation of emissions directly emitted from the affected facility
process unit.)
Then select a position that enables a clear view of the potential
emission point(s) of the affected facility or of the building or
structure housing the affected facility, as appropriate for the
applicable subpart. A position of at least 15 feet but not more than
0.25 mile from the emission source is recommended. For outdoor
locations, select a position where the sun is not directly in the
observer's eyes.
5.2 Field Records
5.2.1 Outdoor Location. Record the following information
on the field data sheet (Figure 22-1): company name, industry,
process unit, observer's name, observer's affiliation, and date.
Record also the estimated wind speed, wind direction, and sky condition.
Sketch the process unit being observed, and note observer location
relative to the source and the sun. Indicate the potential and actual
fugitive emission points on the sketch.
5.2.2 Indoor Location. Record the following information on the
field data sheet (Figure 22-2): company name, industry, process unit,
observer's name, observer's affiliation, and date. Record, as
appropriate, the type, location, and intensity of lighting on the
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data sheet. Sketch the process unit being observed, and note
observer location relative to the source. Indicate the potential
and actual fugitive emission points on the sketch.
5.3 Indoor Lighting Requirements. For indoor locations,
use a light meter to measure the level of illumination at a
location as close to the emission source(s) as is feasible. An
illumination of greater than 100 lux (10 foot candles) 1s
considered necessary for proper application of this method.
5.4 Observations. Record the clock time when observations
begin. Use one stopwatch to monitor the duration of the observa-
tion period; start this stopwatch when the observation period
begins. If the observation period is divided into two or more
segments by process shutdowns or observer rest breaks, stop the
stopwatch when a break begins and restart it without resetting
when the break ends. Stop the stopwatch at the end of the
observation period. The accumulated time Indicated by.this stopwatch
is the duration of the observation period. When the observation
period is completed, record the clock time.
During the observation period, continuously watch the emission
source. Upon observing an emission (condensed water vapor is not
considered an emission), start the second accumulative stopwatch;
stop the watch when the emission stops. Continue this procedure
for the entire observation period. The accumulated elapsed time on
this stopwatch is the total time emissions were visible during the
observation period, i.e., the emission time.
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5.4.1 Observation Period. Choose an observation period of
sufficient length to meet the requirements for determining
compliance with the emission regulation in the applicable subpart.
When the length of the observation period is specifically stated
in the applicable subpart, it may not be necessary to observe
the source for this entire period if the emission time required
to Indicate non-compliance (based on the specified observation
period) is observed in a shorter time period. In other words
if the regulation prohibits emissions for more than 6 minutes in
any hour, then observations may (optional) be stopped after an
emission time of 6 minutes is exceeded. Similarly, when the
regulation is expressed as an emission frequency and the regulation
prohibits emissions for greater than 10 percent of the time in
any hour, then observations may (optional) be terminated after
6 minutes of emissions are observed since 6 minutes 1s 10 percent
of an hour. In any case, the observation period shall not be less
than 6 minutes in duration. In some cases, the process operation
may be Intermittent or cyclic. In such cases, 1t may be
convenient for the observation period to coincide with the length
of the process cycle.
5.4.2 Observer Rest Breaks. Do not observe emissions
continuously for a period of more than 15 to 20 minutes without
taking a rest break. For sources requiring observation periods
of greater than 20 minutes, the observer shall take a break of
not less than 5 minutes and not more than 10 minutes after every
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15 to 20 minutes of observation. If continuous observations are
desired for extended time periods, two observers can alternate
between making observations and taking breaks.
5.5 Recording Observations. Record the accumulated time of
the observation period on the data sheet as the observation period
duration. Record the accumulated time emissions were observed on
the data sheet as the emission time. Record the clock time the
observation period began and ended, as well as the clock time any
observer breaks began and ended.
6. Calculations
If the applicable subpart requires that the emission rate be
expressed as an emission frequency (in percent), determine this
value as follows: Divide the accumulated emission time (in seconds)
by the duration of the observation period (in seconds) or by any
minimum observation period required in the applicable subpart if
the actual observation period is less than the required period,
and multiply this quotient by TOO.
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FUGITIVE EMISSION INSPECTION
OUTDOOR LOCATION
i Location
j Company representative
Observer
Affiliation
Date
Sky conditions
Precipitation
Wind direction
Wind speed —
industry
Process unit
Sketch process unit; indicate observer position relative to source and sun; indicate potential
emission points and/or actual emission points.
1 i
OBSERVATIONS
Clock
time
« Begin observation
Observation
period
duration,
min:sec
Accumulated
emission
time,
min:sec
End observation
Figure 22-1
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TECHNICAL REPORT DATA
l/'li-a\i' rcatl Instruction* on //ic mmr before commit-
4. TITLf /'NO SUBTITLE
Air Pollutant Control Techniques for Crushed and
Broken Stone Industry
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
Atul Kothari and Richard Gerstle
8. PERFORMING ORGANIZATION REPORT NO
) RECIPIENT'S ACCESSION NO.
REPORT DATE
May, 1980
9. PERFORMING ORGANIZATION NAME AND ADDRESS
PEDCo Environmental, Inc.
11499 Chester Road
Cincinnati, Ohio 45246
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-01-4177 and 68-02-2603
12
SPONSORING AGENCY NAME AND ADDRESS.
U.S. Environmental Protection Agency
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, N. C. 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA 200/04
15. SUPPLEMENTARY NOTES
U.S. EPA Project Office: Alfred E. Vervaert
16 ABSTRACT
Air pollutant control technologies for the control of particulate emissions
from crushed and broken stone production facilities are evaluated. Specific control
technologies considered include the use of local ventilation followed by fabric filter
collection and wet dust suppression techniques. Performance data based on mass
particulate measurements and visual observations are presented. In addition, the
capital and annualized emission control costs for several model plant sizes are
estimated. The environmental and energy impacts associated with each control
technology evaluated are also presented. Alternative regulatory options available
are identified and evaluated in terms of their enforceability, impact on the
environment, cost and impact on energy.
17.
J
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
Particulate emissions
Control technology
Crushed and broken stone
b.lOENTIFIERS/OPEN ENDED TERMS
Air pollution control
Particulate control
Fabric filter
Wet dust suppression
Crushed and broken stone
Regulations
COSATi Held/Group
13 B
Ifl
Unlimited
19 SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
267
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS KOI TION i s OBSOLETE
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