BACKGROUND REPORT
AP-42 SECTION 12.18
LEAD-BEARING ORE CRUSHING AND GRINDING
Prepared for
U.S. Environmental Protection Agency
OAQPS/TSD/EIB
Research Triangle Park, NC 27711
Updated March 2007
1-103
Pacific Environmental Services, Inc.
P.O. Box 12077
Research Triangle Park, NC 27709
919/941-0333
Mention of trade names or commercial products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available electronically from the EPA's web
site at http://www.epa.gov/ttn/chief
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TABLE OF CONTENTS
1.0 INTRODUCTION 1
2.0 INDUSTRY DESCRIPTION 2
2.1 GENERAL 2
2.2 PROCESS DESCRIPTION 2
2.3 EMISSIONS AND CONTROLS 2
2.4 REVIEW OF SPECIFIC DATA SETS 5
2.5 REFERENCES FOR CHAPTER 2 7
3.0 GENERAL EMISSION DATA REVIEW AND ANALYSIS
PROCEDURES 8
3.1 LITERATURE SEARCH AND SCREENING 8
3.2 EMISSION DATA QUALITY RATING SYSTEM 9
3.3 EMISSION FACTOR QUALITY RATING SYSTEM 10
3.4 REFERENCES FOR CHAPTER 3 12
4.0 POLLUTANT EMISSION FACTOR DEVELOPMENT 13
4.1 CRITERIA POLLUTANT EMISSIONS DATA 13
4.2 NONCRITERIA POLLUTANT EMISSION DATA 13
4.3 REVIEW OF SPECIFIC DATA SETS 14
4.4 DATA GAP ANALYSIS 15
4.5 REFERENCES FOR CHAPTER 4 16
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LIST OF TABLES
TABLE 2.3-1 (METRIC): EMISSION FACTORS FOR LEAD ORE CRUSHING
AND GRINDING 4
TABLE 2.3-1 (ENGLISH): EMISSION FACTORS FOR LEAD ORE
CRUSHING AND GRINDING 5
TABLE 4.5-1: LIST OF CONVERSION FACTORS 17
in
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1.0 INTRODUCTION
The document "Compilation of Air Pollutant Emission Factors" (AP-42) has been
published by the U.S. Environmental Protection Agency (the EPA) since 1972. Supplements to
AP-42 have been routinely published to add new emission source categories and to update
existing emission factors. AP-42 is routinely updated by the EPA to respond to new emission
factor needs of the EPA, state and local air pollution control programs and industry.
An emission factor relates the quantity (weight) of pollutants emitted to a unit of activity
of the source. The uses for the emission factors reported in AP-42 include:
1. Estimates of area-wide emissions;
2. Emission estimates for a specific facility; and
3. Evaluation of emissions relative to ambient air quality.
The purpose of this report is to provide background information from process
information obtained from industry comment No test reports to support revision of emission
factors were obtained because few tests exist.
Including the introduction (Chapter 1), this report contains four chapters. Chapter 2 gives
a description of the lead-bearing ore crushing and grinding industry. It includes a
characterization of the industry, an overview of the different process types, a description of
emissions, and a description of the technology used to control emissions resulting from lead-
bearing ore crushing and grinding.
Chapter 3 is a review of emissions data collection and analysis procedures. It describes
the literature search, the screening of emission data reports, and the quality rating system for
both emission data and emission factors. Chapter 4 details criteria and noncriteria pollutant
emission factor development. It includes the review of specific data sets and the results of data
analysis. Particle size determination and particle size data analysis methodology are described
when applicable.
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2.0 INDUSTRY DESCRIPTION
2.1 GENERAL
Lead-bearing ore is mined from underground or open pit mines. After extraction, the ore
is processed by crushing, screening and milling. Domestic lead mine production for 1991
totaled 480,000 megagrams (530,000 tons) of lead in ore concentrates, a decrease of some
15,000 megagrams (16,500 tons) from 1990 production.
Except for mines in Missouri, lead ore is closely interrelated with zinc and silver. Lead
ores from Missouri mines are primarily associated with zinc and copper. Average grades of
metal from Missouri mines have been reported as high as 7.2 percent lead, 1 percent zinc, and
0.6 percent copper. Due to ore body formations, lead and zinc ores are normally deep mined
(underground), whereas copper ores are mined in open pits. Lead, zinc, copper, and silver are
usually found together (in varying percentages) in combination with sulfur and/or oxygen.
2.2 PROCESS DESCRIPTION
In underground mines the ore is disintegrated by percussive drilling machines, processed
through a primary crusher, and then conveyed to the surface. In open pit mines ore is loosened
and pulverized by explosives, scooped up by mechanical equipment, and transported to the
concentrator. A trend toward increased mechanical excavation as a substitute for standard
cyclic mine development, such as drill-and-blast and surface shovel-and-truck routines, has
surfaced as an element common to most metal mine cost-lowering techniques.
Standard crushers, screens, and rod and ball mills classify and reduce the ore to powders
in the 65 to 325 mesh range. The finely divided particles are separated from the gangue and are
concentrated in a liquid medium by gravity and/or selective flotation, then cleaned, thickened
and filtered. The concentrate is dried prior to shipment to the smelter.
2.3 EMISSIONS AND CONTROLS
Lead emissions from lead ore crushing and grinding processes are largely fugitive and
are caused by drilling, loading, conveying, screening, unloading, crushing, and grinding. The
primary means of control are good mining techniques and equipment maintenance. These
practices include enclosing the truck loading operation, wetting or covering truck loads and
stored concentrates, paving the road from mine to concentrator, sprinkling the unloading area,
and preventing leaks in the crushing and grinding enclosures. Cyclones and fabric filters can be
used in the milling operations.
Particulate and lead emission factors for lead ore crushing and materials handling
operations are given in Table 12.18-1 and 12.18-2. Additionally, the VOC/PM Speciation
Database (SPECIATE) indicates that several Clean Air Act Amendments (CAA) Title III
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hazardous air pollutants (HAPs) are associated with crushing and grinding lead ores. These
include chromium, manganese, nickel, arsenic, selenium, cadmium, antimony, and mercury, as
well as lead in process emissions.
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TABLE 2.3-1 (METRIC UNITS)
EMISSION FACTORS FOR LEAD ORE CRUSHING AND GRINDING3
All Emission Factors in kg/Mg Feed Processed
Ratings (A-E) Follow Each Factor
Type of ore and Particulate Emission
lead content (wt%) Factor Lead Emission Factor
Leadb
Zinc0
Copperd
Lead-Zince
Copper-Leadf
Copper-Zinc8
Copper-Lead-Zinc8
5.1
0.2
0.2
2.0
2.0
0.2
2.0
0.0195
0.0195
0.0195
0.0195
0.0195
0.0195
0.0195
E
E
E
E
E
E
E
0.001
0.00004
0.00004
0.0004
0.0004
0.00004
0.0004
E
E
E
E
E
E
E
3 Reference 1. Units are expressed as kg of pollutant/Mg ore processed. SCC = Source
Classification Code. PM Emissions Factors are from uncontrolled fines crushing in AP-42
Section 11.19.2. Lead Emissions Factors are the product of the PM Emissions Factors and the
wt% lead content of the ore.
bCharacteristic of some mines in Colorado.
Characteristic of some mines in Alaska, Idaho, and New York.
dCharacteristic of Arizona mines.
Characteristic of some mines in Missouri, Idaho, Colorado, and Montana.
Characteristic of some mines in Missouri.
8Does not appear in ore characterization of the top 25 domestic lead producing mines.
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TABLE 2.3-1 (ENGLISH UNITS)
EMISSION FACTORS FOR LEAD ORE CRUSHING AND GRINDING3
All Emission Factors in kg/Mg Feed Processed
Ratings (A-E) Follow Each Factor
Type of ore and Particulate Emission
lead content (wt%) Factor Lead Emission Factor
Leadb
Zinc0
Copperd
Lead-Zince
Copper-Leadf
Copper-Zinc8
Copper-Lead-Zinc8
5.1
0.2
0.2
2.0
2.0
0.2
2.0
0.030
0.030
0.030
0.030
0.030
0.030
0.030
E
E
E
E
E
E
E
0.002
0.00008
0.00008
0.0008
0.0008
0.00008
0.0008
E
E
E
E
E
E
E
3 Reference 1. Units are expressed as Ib of pollutant/ton ore processed. SCC = Source
Classification Code. PM Emissions Factors are from uncontrolled fines crushing in AP-42
Section 11.19.2. Lead Emissions Factors are the product of the PM Emissions Factors and the
wt% lead content of the ore.
Note: The PM factor was corrected from 0.039 to 0.030. The correction was editorial. Note a
was corrected to read Ib/ton from kg/Mg. No changes were made to the metric table. October
2010-Ron Myers, EPA.
bCharacteristic of some mines in Colorado.
Characteristic of some mines in Alaska, Idaho, and New York.
dCharacteristic of Arizona mines.
Characteristic of some mines in Missouri, Idaho, Colorado, and Montana.
Characteristic of some mines in Missouri.
8Does not appear in ore characterization of the top 25 domestic lead producing mines.
2.4
REVIEW OF SPECIFIC DATA SETS
Pacific Environmental Services (PES) contacted the following sources to obtain the most
up-to-date information on process descriptions and emissions for this industry:
1) ASARCO Inc. Denver, Colorado.
2) Cominco American, Inc. Ironton, Missouri.
3) Doe Run Company Ironton, Missouri.
4) Green Creek Mine, Admiralty Island, Alaska.
5) New Butte Mining Company, Silver Bow, Montana.
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No responses other than telephone conversations with ASARCO Inc., and Cominco
American Inc., were received from any of these companies.
A telephone conversation between PES and ASARCO, Inc. (Reference 8) revealed that
their company does not have emission test results for crushing or grinding operations on file,
simply because they are not required by permitting authorities. Emission tests are performed
only when required for quality control. The emissions are generally calculated using material
balance methods. They utilize wet scrubbers and dry cyclones to control dust emissions. The
information obtained from this company was not used in the update because they had no raw
data on their emissions.
A telephone conversation between PES and Cominco American Inc. (Reference 9)
related information similar to that which was obtained from ASARCO, Inc. Cominco uses a
wet grinding process, resulting in a slurry from which there are essentially no dust emissions.
All of the mining, crushing, and grinding takes place underground. Any tests that would be
performed would only be for quality control measures. However, for Cominco, this is very
unlikely since they do not have an air permit and have no specific requirements with which to
comply. For any possible emission controls, they utilize scrubbers. This company did not have
any source tests. The information from this company was not used in the update since no raw
data on emissions existed for the lead-bearing ore crushing and grinding process.
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2.5 REFERENCES FOR CHAPTER 2
1. Control Techniques for Lead Air Emissions. EPA-450/2-77-012A. U.S. Environmental
Protection Agency. Research Triangle Park, NC. December 1977.
2. W.E. Davis. Emissions Study of Industrial Sources of Lead Air Pollutants. 1970. EPA
Contract No. 68-02-0271. W.E. Davis and Associates, Leawood, KS. April 1973.
3. E.G. Wixson and J.C. Jennett. The New Lead Belt in the Forested Ozarks of Missouri.
Environmental Science and Technology. 9(13): 1128-1133. December 1975.
4. W.D. Woodbury. "Lead." Minerals Yearbook. Volume 1. Metals and Minerals. U.S.
Department of the Interior, Bureau of Mines. 1989.
5. Environmental Assessment of the Domestic Primary Copper. Lead, and Zinc Industry.
EPA Contract No. 68-02-1321. PEDCO-Environmental Specialists, Inc. Cincinnati, OH.
September 1976.
6. A.O. Tanner. Mining and Quarrying Trends in the Metals and Industrial Minerals
Industries. Minerals Yearbook. U.S. Department of the Interior, Bureau of Mines. 1989.
7. VOC/PM Speciation Data System. Radian Corporation. EPA Contract No. 68-02-4286.
November 1990.
8. Telecon between ASARCO, Inc. Denver, Colorado and E. Bowen of Pacific
Environmental Services, Research Triangle Park, NC. September 1992.
9. Telecon between Cominco American, Inc., Ironton, MO, and E. Bowen of Pacific
Environmental Services, Research Triangle Park, NC. September 1992.
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3.0 GENERAL EMISSION DATA REVIEW AND ANALYSIS PROCEDURES
3.1 LITERATURE SEARCH AND SCREENING
The first step of this investigation involved a search of available literature relating to
criteria and noncriteria pollutant emissions associated with lead-bearing ore crushing and
grinding. This search included, but was not limited to, the following references:
AP-42 background files maintained in the Emission Factor and Methodologies Section.
There was no information on lead-bearing ore crushing in the background files.
PM10 "gap filling documents including: "Generalized Particle Size Distributions for Use
in Preparing Size Specific Particulate Emission Inventories" (EPA-450/4-86-013), and "PM10
Emission Factor Listing Developed by Technology Transfer"(EPA-450/4-89-002). No new
information was found from these two references.
"Gap Filling PM10 Emission Factors for Selected Open Area Dust Sources " (EPA-450/4-
88-003). This document gave no emission factors for this source category.
AIRS Facility Subsystem Source Classification Coeds and Emission Factor Listing for
Criteria Air Pollutants (EPA-450/4-90-0003) This document gave specific emission factors for
ore crushing, materials handling, raw material crushing, and grinding that were derived using
emission factors found in previous versions of AP-42. No new information was revealed.
EPA databases, including: Clearinghouse for Inventories and Emission Factors (CHIEF),
VOC/Particulate Matter (PM) Speciation Database Management System (SPECIATE), and
Crosswalk/Air Toxic Emission Factor Data Base Management System (XATEF). No new
information was found in these databases.
To reduce the amount of literature collected to a final group of references pertinent to
this report, the following general criteria were used:
1. Emissions data must be from a primary reference; i.e., the document must constitute
the original source of test data, including raw source data.
2. The referenced study must contain test results based on more than one test run.
3. The report must contain sufficient data to evaluate the testing procedures and source
operating conditions (e.g., one-page reports were generally rejected).
If no primary data (raw data such as source tests) were found and the previous update
utilized secondary data (i.e., data obtained by means other than source tests, such as literature,
industry surveys, etc.), these secondary data were still used and the emission factor rating
lowered, if needed. A final set of reference materials was compiled after a thorough review of
the pertinent reports, documents, and information according to these criteria. The final set of
reference materials is given in Chapter 4.
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3.2 EMISSION DATA QUALITY RATING SYSTEM
As part of Pacific Environmental Services' analysis of the emission data, the quantity and
quality of the information contained in the final set of reference documents were evaluated. The
following data were excluded from consideration.
1. Test series averages reported in units that cannot be converted to the selected
reporting units;
2. Test series representing incompatible test methods (e.g., comparison of the EPA
Method 5 front-half with the EPA Method 5 front- and back-half);
3. Test series of controlled emissions for which the control device is not specified;
4. Test series in which the source process is not clearly identified and described; and
5. Test series in which it is not clear whether the emissions were measured before or
after the control device.
Data sets that were not excluded were assigned a quality rating. The rating system used
was that specified by the OAQPS for the preparation of AP-42 sections. The data were rated as
follows:
A
Multiple tests performed on the same source using sound methodology and reported in
enough detail for adequate validation. These tests do not necessarily conform to the
methodology specified in the EPA reference test methods, although these methods were
certainly used as a guide for the methodology actually used.
B
Tests that were performed by a generally sound methodology but lack enough detail for
adequate validation.
C
Tests that were based on an untested or new methodology or that lacked a significant
amount of background data.
D
Tests that were based on a generally unacceptable method but may provide an order-of-
magnitude value for the source.
The following criteria were used to evaluate source test reports for sound methodology
and adequate detail:
1. Source operation. The manner in which the source was operated is well documented
In the report. The source was operating within typical parameters during the test.
2. Sampling procedures. The sampling procedures conformed to a generally acceptable
methodology. If actual procedures deviated from accepted methods, the deviations
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are well documented. When this occurred, an evaluation was made of the extent
such alternative procedures could influence the test results.
3. Sampling and process data. Adequate sampling and process data are documented in
the report. Many variations can occur unnoticed and without warning during testing.
Such variations can induce wide deviations in sampling results. If a large spread
between test results cannot be explained by information contained in the test report,
the data are suspect and were given a lower rating.
4. Analysis and calculations. The test reports contain original raw data sheets. The
nomenclature and equations used were compared to those (if any) specified by the
EPA to establish equivalency. The depth of review of the calculations was dictated
by the reviewer's confidence in the ability and conscientiousness of the tester, which
in turn was based on factors such as consistency of results and completeness of
other areas of the test report.
3.3 EMISSION FACTOR QUALITY RATING SYSTEM
The quality of the emission factors developed from analysis of the test data was rated
utilizing the following general criteria:
A (Excellent)
Developed only from A-rated test data taken from many randomly chosen facilities in the
industry population. The source category is specific enough so that variability within the
source category population may be minimized.
B (Above average)
Developed only from A-rated test data from a reasonable number of facilities. Although
no specific bias is evident, it is not clear if the facilities tested represent a random sample
of the industries. As in the A-rating, the source category is specific enough so that
variability within the source category population may be minimized.
C (Average)
Developed only from A- and B-rated test data from a reasonable number of facilities.
Although no specific bias is evident, it is not clear if the facilities tested represent a
random sample of the industry. As in the A-rating, the source category is specific enough
so that variability within the source category population may be minimized.
D (Below average)
The emission factor was developed only from A- and B-rated test data from a small
number of facilities, and there is reason to suspect that these facilities do not represent a
random sample of the industry. There also may be evidence of variability within the
source category population. Limitations on the use of the emission factor are noted in the
emission factor table.
E (Poor)
10
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The emission factor was developed from C- and D-rated test data, and there is reason to
suspect that the facilities tested do not represent a random sample of the industry. There
also may be evidence of variability within the source category population. Limitations on
the use of these factors are always noted.
The use of these criteria is somewhat subjective and depends to an extent on the
individual reviewer.
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3.4 REFERENCES FOR CHAPTER 3
1. Technical Procedures for Developing AP-42 Emission Factors and Preparing AP-42
Sections. U.S. Environmental Protection Agency, Emissions Inventory Branch, Office of
Air Quality Planning and Standards, Research Triangle Park, NC 27711, April 1992.
[Note: this document is currently being revised at the time of this printing.]
2. AP-42. Supplement A, Appendix C.2, "Generalized Particle Size Distributions." U.S.
Environmental Protection Agency, October 1986.
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4.0 POLLUTANT EMISSION FACTOR DEVELOPMENT
4.1 CRITERIA POLLUTANT EMISSIONS DATA
Because no processes involving combustion or other chemical changes are used in lead-
bearing ore crushing and grinding operations, no data on emissions of nonmethane organics,
nitrogen oxides, carbon monoxide, or sulfur dioxide were found nor expected from this
industry.
Lead and particulate emissions are the only emissions to be expected from this process.
No new data on particulate emissions and lead emissions were found. Conversations with two
different companies (ASARCO, Inc. and Cominco American, Inc.) revealed that source tests on
lead-bearing ore crushing and grinding are usually only performed if a problem with fugitive
emissions has been identified. Therefore, emission testing is limited to facilities that have been
identified as emitting substantial quantities of product. Due to the lack of new data, the
emission factors have been transferred directly from Section 12.18 of the previous AP-42 into
the revised section.
4.2 NONCRITERIA POLLUTANT EMISSION DATA
Hazardous Air Pollutants.
Hazardous Air Pollutants (HAPs) are defined in Title III of the 1990 Clean Air Act
(CAA) Amendments. The VOC/PM Speciation Database (SPECIATE) indicates that the
following CAA Title III HAPs are associated with crushing and grinding of lead ores:
chromium, manganese, nickel, arsenic, selenium, cadmium, antimony, and mercury, as well as
lead in process emissions. No data on emissions of any of these pollutants were found for the
lead-bearing ore crushing and grinding processes.
Global Warming Gases.
Pollutants such as methane (CH4), carbon dioxide (C02), and nitrous oxide (N2O) have
been found to contribute to overall global warming. No data on emissions of these pollutants
were found for the lead-bearing ore crushing and grinding process.
Stratospheric Ozone-Depleting Gases.
Chlorofluorocarbons have been found to contribute to ozone depletion. No data on
emissions of these pollutants were found for the lead-bearing ore crushing and grinding
process.
4.3 REVIEW OF SPECIFIC DATA SETS
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None of the emission factors presented in the previous version of AP-42 section 12.18
could be verified. For this reason, along with the fact that no new data could be obtained, the
emission factors were not changed. Since PES could not review most of the old references, a
determination on whether to downgrade the emission factors cannot be made at this time.
Therefore, the emission factor rating of "B" has been retained.
References 1. 2. 3. and 5
These references are the basis for the emission factors presented in the previous version
of AP-42 section 12.18. PES could not obtain a copy of Reference 1 (Control Techniques for
Lead Air Emissions. EPA-450/2-77-012A) from the EPA library; this particular document
could not be located. Reference 2 could not be found in the file and also could not be located by
the EPA library. PES was able to locate and review Reference 3. Reference 3 is an article on
environmental information on the lead industry, and does not contain any emission information
for this process. It could not be used to verify the emission factors in the previous version of
AP-42 section 12.18. Reference 5 could not be located in the background file or otherwise
obtained.
In 2007, a copy of Reference 1 was located in the EPA Region VII library was scanned and
posted to http://www.epa.gov/ttn/chief/old/ap42/chl2/s06/reference/refl4_cl2s06_1995.pdf.
This document provides no detailed information on the derivation or selection of the PM or
Lead emissions factors that were originally in the section. The range of lead emissions factors
in this original section are reflected in Table 2-8 of this document.
An examination of the particulate matter emissions factors (6 #/ton)used for lead,zinc, and lead
zinc presented in this section previously are identical to the uncontrolled total parti culate matter
emissions factors for tertiary crushing and screening available in the 1975 version of Stone
Quarrying and processing. It is likely that the emissions factors for Reference 1 and for this
section were extracted from this AP-42 section. It is unclear why the slightly larger (6.4 #/ton)
particulate matter emissions factors for copper, copper-lead, copper-zinc and copper-lead-zinc
were used. In 1985, the emissions factors for crushed stone processing were revised to a
somewhat lower value (1.85 #/ton) based upon data that ranged from 0.0016 to 2.76 #/ton. In
2004 an emissions factor for fines crushing was added to the factors for crushed stone
processing. The uncontrolled emissions factor for fines crushing was selected as the most
appropriate for uncontrolled leadbearing ore crushing since the tertiary crushing at crushed
stone plants produces material between 3/16 inch and 1 inch. The process used for leadbearing
ore crushing appears to produce smaller material.
References 4 and 6
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References 4 and 6 are both articles in a widely available non-technical reference
document. They contain general information concerning the lead industry. No emission
information was contained in either of the articles.
Reference 7
The VOC/PM Speciation Database (SPECIATE) indicated that the following CAA Title
III HAPs are associated with the crushing and grinding of lead ores. These include chromium,
manganese, nickel, arsenic, selenium, cadmium, antimony, and mercury, as well as lead in
process emissions. However, no new information on this process could be obtained using this
database.
4.4 DATA GAP ANALYSIS
According to the companies that were contacted, very few source tests exist for this
industry. The companies contacted also indicated that it is difficult to quantify such fugitive
emissions due to the nature of this process. Source tests are only performed for quality control
measures. The best way to control emissions from this process is to use good mining techniques
and equipment maintenance. Having the process enclosed with wet sprayers can aid in the
control of fugitive emissions. Cyclones and fabric filters can also be used in the milling
operations.
Most of the information on lead-bearing ore crushing and grinding processes is general
in nature and generally pertains to the production of lead, and not specifically to crushing and
grinding. It is the position of several members of the industry that emission testing is not
practical or necessary, due to the fugitive nature of the emissions. Another option to control
emissions could be to enclose the entire operation. This alternative, in most if not all cases,
would appear to be economically unfeasible.
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4.5 REFERENCES FOR CHAPTER 4
1. Control Techniques for Lead Air Emissions. EPA-450/2-77-012A. U.S. Environmental
Protection Agency. Research Triangle Park, NC. December 1977.
2. W.E. Davis. Emissions Study of Industrial Sources of Lead Air Pollutants. 1970. EPA
Contract No. 68-02-0271. W.E. Davis and Associates, Leawood, KS. April 1973.
3. E.G. Wixson and J.C. Jennett. The New Lead Belt in the Forested Ozarks of Missouri.
Environmental Science and Technology. 9(13): 1128-1133. December 1975.
4. W.D. Woodbury. "Lead." Minerals Yearbook. Volume 1. Metals and Minerals. U.S.
Department of the Interior, Bureau of Mines. 1989.
5. Environmental Assessment of the Domestic Primary Copper. Lead, and Zinc Industry.
EPA Contract No. 68-02-1321. PEDCO-Environmental Specialists, Inc. Cincinnati, OH.
September 1976.
6. A.O. Tanner. Mining and Quarrying Trends in the Metals and Industrial Minerals
Industries. Minerals Yearbook. U.S. Department of the Interior, Bureau of Mines. 1989.
7. VOC/PM Speciation Data System. Radian Corporation. EPA Contract No. 68-02-4286.
November 1990.
16
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TABLE 4.5-1
LIST OF CONVERSION FACTORS
Multiply:
mg/dscm
m2
M3
m
kg
kPa
kg/Mg
Mg
by:
4.37 xlO'4
10.764
35.31
3.281
2.205
1.45X10'1
2.0
1.1023
To obtain:
gr/dscf
ft2
ft3
ft
Ib
psia
Ib/ton
ton
Temperature conversion equations:
Fahrenheit to Celsius:
_ (°F-32)
1.8
Celsius to Fahrenheit:
°F = 1.8(°C) + 32
17
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