EPA Project Report No. 75-STN-9
O
Caldwell Stone Co.
Danville, Kentucky
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Emission Measurement Branch
Research Triangle Park. North Carolina
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REPORT ON VISIBLE EMISSIONS
AT CALDWELL STONE COMPANY'S
LIMESTONE QUARRY
DANVILLE, KENTUCKY
AUGUST, 1975
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73-153-006
REPORT ON VISIBLE EMISSIONS
AT CALDWELL STONE COMPANY'S
LIMESTONE QUARRY
DANVILLE, KENTUCKY
AUGUST, 1975
PREPARED AND SUBMITTED BY:
ENVIRONMENTAL SCIENCE AND ENGINEERING, INC.
PREPARED FOR:
U.S. ENVIRONMENTAL PROTECTION AGENCY
EMISSIONS MEASUREMENT BRANCH
RESEARCH TRIANGLE PARK, N.C.
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TABLE OF CONTENTS
Section Page
LIST OF TABLES AND FIGURES ii
1.0 INTRODUCTION 1
2.0 SUMMARY AND DISCUSSION OF RESULTS 3
3.0 PROCESS DESCRIPTION AND OPERATION 9
4.0 LOCATION OF SAMPLING POINTS 11
5.0 SAMPLING PROCEDURES 12
APPENDICES
A - FIELD DATA SHEETS
B - SMOKE READER'S CERTIFICATION
C - PROJECT PARTICIPANTS
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LIST OF TABLES AND FIGURES
TABLE 1 SUMMARY OF SIX MINUTE AVERAGE OPACITY READINGS
FOR CALDWELL STONE COMPANY 4-5
Figure 1 OPACITY PLOTS 6-7
Figure 2 CALDWELL STONE COMPANY DRILLING UNIT 8
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1.0 INTRODUCTION
Under the Clean Air Act, as amended, the Environmental Protection Agency
is charged with the establishment of performance standards for new instal-
lations or modifications of existing installations in stationary source
categories which may contribute significantly to air pollution. A per-
formance standard is a standard for emissions of air pollutants which
reflects the best emission reduction systems that have been adequately
demonstrated (taking into account economic considerations).
The development of realistic performance standards requires accurate data
on pollutant emissions within the various source categories.
This report presents the results of the testing which was performed at
the Caldwell Stone Company, Danville, Kentucky.
Caldwell Stone Company operates a limestone crushing facility located in
Danville, Kentucky. The operation consists of mining raw limestone and
processing the rock into various size fractions for use in the cement and
aggregate industry.
On June 2, 1975, a testing team consisting of one (1) representative from
Environmental Science and Engineering, Inc, (ESE) and one (1) repre-
sentative from the U.S. Environmental Protection Agency (EPA) conducted
visible emissions tests. The purpose of these tests was to provide
quantitative data, judged by visual observations, on the collection
efficiency of the drill shroud used to contain emissions on the blasting
hole drilling unit. The data were collected using a modification of EPA
Method 9 for the determination of visible emissions.
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The area of observation at this facility was within the quarry itself
and did not concern the rock crushing plant. The only equipment tested
for visual emissions was a blasting hole drilling unit used for the
purpose of drilling holes. After being drilled, the holes are filled
with explosives and a portion of the limestone cliff blasted away.
Emissions from the blast were not observed.
In order that the tests performed could be as representative of the
process as possible, the drilling unit drilled the equivalent of one (1)
complete hole. This was done as follows: readings were recorded for the
second half of drilling on the first hole observed; the drilling unit
moved to a new location where it started a new hole and readings were
recorded for the first half of this hole, thereby giving the equivalent
of one completely drilled hole.
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2.0 SUMMARY AND DISCUSSION OF RESULTS
A summary of the field data, reduced to six-minute averages, is included
in Table 1, and graphically demonstrated in Figure 1. Since the field
data consisted of four readings each minute, values reported in this
table are averages for 24 individual readings with corresponding "mean"
values being the sum divided by 24.
The majority of emissions observed during testing was emitted from a wide
gap around the drill shaft access which allows continuous emission of
dust (See Figure 2). The quantity of emissions appeared to be small
relative to those captured by the dust control shroud. Closer evaluation
of the data indicates that emissions were related to the drilling hole
depth, i.e., on the second half of the first drilled hole no emissions
were observed, whereas on the first half of the second hole emissions
were observed escaping from the shroud edges.
There were no pressure drop readings taken on the baghouse because no taps
were available; however, the unit appeared to be operating normally as
evidenced by the quantity of dust which was removed from the baghouse at
the completion of each hole.
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TABLE 1
SUMMARY OF SIX MINUTE AVERAGE
OPACITY READINGS
CALDWELL STONE COMPANY
OBSERVED READINGS
START
DATE TIME
7/2/75 0845
0851
0857
0903
0909
0915
0921
0927
0933
*• 0939
0945
0951
0957
1003
1030
1037
1043
1049
1055
1101
END
TIME
0850
0856
0902
0908
0914
0920
0926
0932
0938
0944
0950
0956
1002
1009
1036
1042
1048
1054
1100
1106
SET
NUMBER
1-6
7-12
13-18
19-24
25-30
31-36
37-42
43-48
49-54
55-60
61-66
67-72
73-78
79-84
85-90
91-96
97-102
103-108
109-114
115-120
J. Cross M.
SUM MEAN SUM
0
290
435
475
455
380
150
255
390
395
350
330
250
115
205
345
360
365
355
190
Jackson
MEAN
0
12.08
18.13
19.79
18.96
15.83
6.25
10.63
16.25
16.46
14.58
13.75
10.42
4.79
8.54
14.38
15.00
15.21
14.79
11.88
G. McRae J.
SUM MEAN SUM
0
285
360
375
370
355
120
155
300
240
285
255
185
100
130
195
280
305
265
175
W. Brown
MEAN
0
11.88
15.00
15.63
15.42
14.79
5.00
6.46
12.50
10.00
11.88
10.63
7.71
5.00
5.42
8.13
11.67
12.71
11.04
7.29
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TABLE
1 SUMMARY OF SIX MINUTE AVERAGE
OPACITY READINGS
CALDWELL STONE COMPANY
OBSERVED READINGS
DATE
7/2/75
START
TIME
1107
1113
1119
1125
1131
1137
1143
1149
1155
END
TIME
1112
1118
1124
1130
1136
1142
1148
1154
1200
SET
NUMBER
121-126
127-132
133-138
139-144
145-150
151-156
157-162
163-168
169-174
J. Cross M.
SUM MEAN SUM
130
380
295
390
410
380
315
270
75
Jackson
MEAN
13.00
15.83
12.29
16.25
17.08
15.83
13.13
11.25
7.08
G. McRae J.
SUM MEAN SUM
140
260
225
370
385
325
225
160
W. Brown
MEAN
5.83
10.83
9.38
15.42
16.04
13.54
9.38
6.67
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Figure 1
Opacity Plots
Caldwell Stone Co.
7-2-75
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Fi gure 2
CALDWELL STONE COMPANY
Drilling Unit
7-2-75
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3.0 PROCESS DESCRIPTION AND OPERATION
Process operations at Caldwell Stone are comprised of quarring, primary
crushing, and secondary crushing. Because the tests conducted there were
concerned with only one aspect of the quarry operation, the blast hole
drilling process, only the quarry operation will be described,
3.1 QUARRY OPERATION
Limestone is removed from the quarry walls by first removing 20 to 30 feet
of overburden consisting of soil, shale and unusable grades of limestone.
After removing the overburden, 80-foot benches are blasted from the quarry
walls. Blasting is accomplished by drilling a series of 5-inch diameter,
80-foot deep blasting holes into the quarry shelf in such a pattern that
when the holes are charged and blasted, the blast will shear off a section
of the quarry wall. The sheared section falls onto the quarry floor where
it is loaded into 30-ton trucks and transported to the primary crusher.
The drilling of the 5-inch diameter, 80-foot deep blasting holes is done
by two Schranm C-42 rotary drills. The C-42 is a pneumatic type drill
which is mounted on the front of a mobile air compressor unit that has
crawler track drive. The air compressor is powered by a diesel engine,
The compressed air which operates the drill is discharged at the drill
head at the rate of 250 cfm. The drill head is attached to a 20-foot
drill rod. When the hole depth reaches 20 feet, a 20-foot extension is
added to the drill which allows the drill to extend another 20 feet, A
total of three extensions are used to reach a depth of 80 feet, Each hole
takes two to three hours to drill. Adding extensions during the drilling
process usually requires less than five minutes down time. The holes are
drilled down into the shelf every 16 feet in rows 11 feet apart. Hole
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drilling is usually conducted every day, except during blasting. Blasting
occurs every two to three weeks. The air pollution emissions which occur
during the drilling process are controlled by a small baghouse mounted
directly on the air compressor/drill unit.
Because Caldwell Stone drills 80-foot holes instead of nominal 30-foot
holes used by most quarries, the water injection technique for controlling
dust emissions from the drilling process is not used. Previous attempts
to use the water injection technique resulted in the loss of several drill
heads because they became stuck in the wet slurry that formed in the hole.
This problem was attributed to the unusually deep holes.
The baghouse unit is a size 12 "Sly Economy Dust Filter" equipped with
a hand-operated bag shaker mechanism. The collector has 12 bags which
total 264 square feet of cloth area. Air is drawn into the baghouse
through a 7-inch duct which is attached to a collar that is suspended at
ground level over the drill hole. A 600 cfm blower, located in the bag-
house outlet duct, provides the necessary suction. The blower is driven
by a pneumatic motor. At 600 cfm, the resulting air-to-cloth ratio is
about 2.3 cfm/ft2. The cleaned air outlet consists of a 7-inch diameter
vertical duct which is attached to the blower outlet, The bags are shaken
after drilling each hole and occasionally they are also shaken when drill
extensions are added.
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4.0 LOCATION OF SAMPLING POINTS
The only emissions observed at this plant were from the blasting hole
drilling unit within the quarry, The drill shroud was the specific
sampling point observed at this plant. As indicated in the introduction,
the first set of observations were taken during the second half of a
drilling operation. The second set was taken during the first half of
drilling. Again, this was done to obtain a representative sample.
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5,0 SAMPLING PROCEDURES
Due to the nature of the operations observed, i,e,, the lack of any
process stacks, it was necessary to adapt EPA Method 9 for determining
visible emissions. For this reason, and because of the nature of the
viewing backgrounds, the requirements for observer location relative to
the sun specified in Method 9 were disregarded for these tests. Addition-
ally, the observers were located much closer to the sources than is normal
to ensure adequate visual access to any fugitive emissions. Other than
the exceptions noted, EPA Method 9, as described in the Federal Register,
Vol. 39, No. 219, November 12, 1974, was the testing method utilized.
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