40 CFR Part 61                                              EPA 520/1-85-010
National Emission Standards
for Hazardous Air Pollutants
                    DRAFT BACKGROUND INFORMATION DOCUMENT

                  PROPOSED STANDARD FOR RADON-222 EMISSIONS
                    TO AIR FROM UNDERGROUND URANIUM MINES
                              February 14, 1985
                         Document No. (PEI 3642-12)
                    U.S. Environmental Protection Agency
                        Office of Radiation Programs
                           Washington, D.C.  20460

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                                CONTENTS

                                                                 Page

Figures                                                           vi
Tables                                                           vii

1.   INTRODUCTION                                                1-1

          1.1  History of Standard Development                   1-1
          1.2  Purpose and Scope of This Background Information
                 Document                                        1-3
          1.3  Other Regulatory Factors                          1-3

2.   INDUSTRY DESCRIPTION                                        2-1

          2.1  Overview                                          2-1
          2.2  Process Description                               2-2
                    2.2.1  Underground Uranium Mining            2-2
                    2.2.2  Ore Handling                          2-5
                    2.2.3  Ventilation Techniques                2-5
          2.3  Economic Profile of the Underground Mining
                 Industry                                        2-6
                    2.3.1  Domestic Uranium Production           2-6
                    2.3.2  The Underground Uranium Mining
                             Industry                            2-12
                    2.3.3  Forecasts of Domestic Production      2-15

References                                                       2-20

3.   ATMOSPHERIC EMISSION OF RADON-222                           3-1

          3.1  Theoretical Considerations                        3-1
                    3.1.1  Origin and Generation of Radon-222    3-1
                    3.1.2  Factors Affecting Emissions of
                             Radon-222 to Air                    3-3
                    3.1.3  Difficulties in Estimating Radon-
                             222 Emissions                       3-3
          3.2  Radon-222 Emissions                               3-4
                    3.2.1  Radon-222 Sources                     3-4
                    3.2.2  Measured Emissions                    3-4
                    3.2.3  Relationship of Cumulative Ore
                             Production to Radon-222 Emissions   3-7
                    3.2.4  Estimated Future Emissions            3-7
          3.3  Ambient Air Concentrations                        3-12
                    3.3.1  New Mexico Study                      3-12
                    3.3.2  Kerr-McGee Data                       3-18
                    3.3.3  Additional Study Needed               3-18

References                                                       3-20
                                   iii

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CONTENTS (continued)
4.
ESTIMATING THE RISK DUE TO EXPOSURE FROM RADON-222
DECAY PRODUCTS
References
Introduction
Radon-222 Exposure Pathways
4.2.1 Physical Considerations
4.2.2 Characterizing Exposures to the
General Population Vis-A-Vis
Underground Mines
From Exposure to Radon-222 Decay
4.1
4.2
4.3
Health Risk
Products
4.3.1
4.3.2
4.3.3
4.3.4
Estimating
4.4.1
4.4.2
4.4
5.
RISK ASSESSMENT
References
6.
Introduction
Reference Underground Uranium Mine
5.2.1 Description
5.2.2 Health Risk Assessment of the Ref-
erence Underground Uranium Mine
Total Health Risk From Radon-222 Emissions
From All Underground Uranium Mines
Case Study Mines
5.4.1 Description
5.4.2 Health Risk Assessment of Case
Study Mines
5.1
5.2
5.3
5.4
CONTROL TECHNIQUES
6.1
6.2
Risk Models
The EPA Relative Risk Model
Other Risk Estimates
Comparison of Risk Estimates
the Risks
Exposure
Risk Estimation
Introduction
Controlling Radon-222 in Mine Ventilation
(Exhaust) Air
6.2.1 Adsorption
6.2.2 Cryogenic Condensation
6.2.3 Separation
6.2.4 Absorption
6.2.5 Other Possible Methods
6.2.6 Summary
iv
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6-1
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CONTENTS (continued)
6.3
Methods for Preventing Radon-222 From Entering
the Ventilation Air
6.3.1 Sealants
6.3.2 Backfilling
6.3.3 Bulkheads
6.3.4 Mine Pressurization for Radon-222
Control
References
Appendices
A - List of Underground Uranium Mines
B - Data for Use in Estimating Risks to Individuals Near
Underground Uranium Mines
C - Calculations on Bulkhead Effectiveness at Various Air
Removal Rates
D - Estimated Costs of Bleedstream Control With Activated
Carbon
Glossary
v
6-8
6-10
6-13
6-13
6-20
6-21
A-I
B-1
C-l
D-l
G-l

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Number
2-1
2-2
3-1
3-2
3-3
3-4
4-1
4-2
5-1
5-2
5-3
6-1
6-2
FIGURES
Schematic diagram of an underground uranium mine
Ventilation shaft vertical and horizontal exhaust
vents
Uranium-238 decay chain
Relationship of annual radon-222 emission rate to
cumulative ore production
First-year radon-222 averages by station
Second-year radon-222 averages by station
Radon-222 decay series
U.S. lung cancer mortality by age--1970
Reference underground mine
Modeled incremental radon-222 concentrations around
the reference underground uranium mine, assuming
no plume rise
Modeled incremental radon-222 concentrations around
the reference underground uranium mine, assuming
a plume rise
Example plywood bulkhead with plastic liner
Example bulkhead with coating
vi
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2-7
3-2
3-10
3-15
3-16
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4-8
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5-7
5-8
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Number
2-1
2-2
2-3
2-4
2-5
2-6
2-7
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
4-1
4-2
TABLES
Historical trends in U.S. uranium production
Employment in the U.S. uranium industry, 1979-1983
Capital expenditures in the U.S. uranium industry
Status of U.S. nuclear powerplants as of December
31, 1983
Uranium production by mining method
Underground uranium mining statistics
Historical and projected U30a production, market
share, and capacity utilization index by source
Summary of radon-222 emissions from underground mine
vents
Mine size categories and percentages of the uranium
industries radon-222 emissions
Correlation between radon-222 emissions and cumulative
ore production
Predicted radon-222 emissions from underground
uranium mine vents
First-year radon-222 averages by station
Second~year radon-222 averages by station
t-test probability values comparing radon-222 con-
centrations at mine mill stations with background
and regulatory limits
Radon-222 concentration for mine 1
Radon-222 concentration for mine 2
Potential alpha energy inhaled during one year of
exposure to one working level as a function of age
Age-dependent risk coefficients and minimum induction
period for lung cancer due to inhaling radon-222
progeny
vii
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2-9
2-10
2-11
2-13
2-14
2-16
2-19
3-6
3-7
3-9
3-11
3-13
3-14
3-17
3-19
3-19
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Number
4-3
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4-5
5-1
5-2
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5-4
5-5
5-6
5-7
5-8
5-9
5-10
6-1
6-2
TABLES (continued)
Risk estimates for exposure to radon-222 progeny
Radon-222 decay product equilibrium fraction at
selected distances from a mine vent
Lifetime risk for lifetime exposure to a given level
of radon-222 progeny
Summary of radon-222 emissions from underground
uranium mines
Estimated ore production of large underground
uranium mines, 1982
Reference underground uranium mine parameters
Estimates of radon-222 concentrations in air at
selected distances from the reference underground
uranium mine
Estimates of annual radon-222 decay product exposures
and lifetime risks of fatal cancer at selected
distances from the reference underground uranium
mine
Annual radon-222 decay product exposures and number
of fatal cancers to the population from radon-222
emissions from the reference underground uranium
mine
Characteristics of Ambrosia Lake site
Estimates of total health risk from radon-222 emis-
sions from all underground uranium mines for the
years 1978, 1982, 1983, 1985, and 1990
Estimates of radon-222 concentrations in air at
selected distances from the case study mines 11
and 12
Estimates of annual radon-222 decay product exposures
and lifetime risks of fatal cancer at selected
distances for case study mines 11 and 12
Summary of possible control techniques for radon-222
emissions in mine ventilation exhausts
Cost of components of bulkhead construction
viii
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4-12
4-16
4-17
5-2
5-3
5-4
5-9
5-10
5-11
5-12
5-12
5-14
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Chapter 1:
INTRODUCTION
1.1
History of Standard Development
In 1977, Congress amended the Clean Air Act (the Act) to address
airborne emissions of radioactive materials. Before 1977, these emis-
sions were either regulated under the Atomic Energy Act or unregulated.
Section 122 of the Act requires the Administrator of the U.S. Environ-
mental Protection Agency (EPA), after providing public notice and oppor-
tunity for public hearings (44 FR 21704, April 11, 1979) to determine
whether emissions of radioactive pollutants cause or contribute to air
pollution that may reasonably be expected to endanger public health. On
December 27, 1979, EPA published a notice in the Federal Register listing
radionuclides as hazardous air pollutants under Section 112 of the Act
(44 FR 76738, December 27, 1979). To support this determination, EPA
published a report entitled "Radiological Impact Caused By Emissions of
Radionuclides into Air in the United States--Preliminary Report" (EPA
520/7-79-006, Office of Radiation Programs, U.S. EPA, Washington, D.C.;
August 1979).
On June 16, 1981, the Sierra Club filed suit in the U.S. District
Court for the Northern District of California pursuant to the citizens'
suit provision of the Act (Sierra Club v. Gorsuch, No. 81-2436 WTS). The
suit alleged that EPA had a nondiscretionary duty to propose standards
for radionuclides under Section 112 of the Act within 180 days after
listing them. On September 30, 1982, the Court ordered EPA to publish
proposed regulations establishing emission standards for radionuclides
within 180 days of the date of that order.
On April 6, 1983, EPA published a notice in the Federal Register
proposing standards for radionuclide emission sources in four categories:
(1) Department of Energy (DOE) facilities, (2) Nuclear Regulatory
Commission (NRC) -licensed facilities and non-DOE Federal facilities,
(3) underground uranium mines, and (4) elemental phosphorus plants. Five
additional categories of sources that emit radionuclides were identified,
but it was determined that there were good reasons for not proposing
standards for them. These included (1) coal-fired boilers; (2) the phos-
phate industry; (3) other extraction industries; (4) uranium fuel cycle
facilities, uranium mill tailings, and management of high-level radioac-
tive waste; and (5) low-energy accelerators (48 FR 15077, April 6, 1983).
To support these proposed standards and determinations, EPA published a
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draft report entitled "Background Information Document, Proposed Stan-
dards for Radionuclides" (EPA 520/1-83-001, Office of Radiation Programs,
U.S. EPA, Washington, D.C., March 1983).
On February 17, 1984, the Sierra Club filed suit to compel final ac-
tion in the U.S. District Court for the Northern District of California,
pursuant to the citizens' suit provision of the Act (Sierra Club ~.
Ruckelshaus, No. 84-0656 WHO). On July 25, 1984, the Court granted
Sierra Club's summary judgment motion and ordered EPA to promulgate
standards or to make a finding that radionuclides are not a hazardous air
pollutant within 90 days of the date of the order.
On October 23, 1984, EPA withdrew its proposed standards for radio-
nuclide emissions from the following categories: (1) elemental phospho-
rus plants; (2) DOE facilities; (3) NRC-licensed facilities and non-DOE
Federal facilities; and (4) underground uranium mines. The Agency also
affirmed its original decision not to regulate emissions from the five
other source categories considered (49 FR 43906, October 31, 1984). The
proposed standards for the first three categories were withdrawn because
the Administrator determined that current practice provides an ample
margin of safety in protecting the public health from the hazards associ-
ated with exposure to radionuclides from these sources.
In the case of underground uranium mines, the Administrator withdrew
the proposed standard because it did not meet the legal requirements of
Section 112 of the Clean Air Act. Simultaneous with this action, the
Agency published an Advance Notice of Proposed Rulemaking for radon-222
emissions from underground uranium mines. The purpose of this was to
solicit additional information on control methods such as bulkheading and
other forms of operational controls for radon-222 that would meet the
legal requirements of Section 112 (40 FR 43915, October 31, 1984). At
the same time, the Agency also published an Advance Notice of Proposed
Rulemaking for radon-222 emissions from operating uranium mills (49 FR
43916, October 31, 1984).
On October 31, 1984, the U.S. District Court, Northern District of
California issued an order requiring the Administrator and the Agency to
show cause why they should not be held in contempt of the Court's July 25
order. A Court hearing was held on November 21, 1984, to consider the
issue. In a ruling on December 11, 1984, the Court found the Administra-
tor and the Agency in contempt and ordered the following remedial action:
1. (a) Issue within 30 days of the date of the order final radionu-
clide emission standards for DOE facilities, NRC-licensed and non-DOE
Federal facilities, and elemental phosphorus plants, and
(b) Issue within 120 days of the date of the order final radio-
nuclide emission standards for uranium mines; or
2. Make a finding based on the information presented at hearings
during the rulemaking, that radionuclides are clearly not a hazardous
pollutant.
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On December 21, 1984, EPA requested a stay of the District Court's
order; this request was denied on January 3, 1985. The Agency subse-
quently requested a stay from the 9th Circuit Court of Appeals on January
8, 1985. This request also was denied; however, the Court did allow the
Agency an additional 7 days to provide time for further appeal to the
U.S. Supreme Court. These efforts also failed. Therefore, to comply
with the District Court's order, EPA is promulgating standards for radio-
nuclide emissions to air from DOE facilities, NRC-licensed and non-DOE
Federal facilities, and elemental phosphorus plants. Litigation regard-
ing these three standards is continuing.
1.2
Purpose and Scope of This Background Information Document
This document presents background data and other pertinent informa-
tion on underground uranium mining and related emissions of radionu-
cliJes, the risks associated with these emissions, and methods for
reducing the emissions. Information was compiled from the technical
literature, previous studies by EPA and the Bureau of Mines, comments
received from rulemaking notices, and discussions with industry repre-
sentatives.
1.3
Other Regulatory Factors
The Department of Labor's Mine Safety and Health Administration
(MSHA) has established limits on exposures to radon decay products for
mine workers. The current standard limits annual exposure to 4 WLM
(Working Level Months) and prohibits exposure to concentrations greater
than 1.0 WL (Working Level) in any active area unless approved respira-
tors are worn (30 CFR 57).
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Chapter 2:
INDUSTRY DESCRIPTION
2.1
Overview
The uranium mining industry in the United States was originally
established at the end of World War II in response to a large government
military program, and this initial demand for uranium resulted in exten-
sive exploration for uranium and the development of the uranium extrac-
tion industry.
In the United States, large ore deposits are located in parts of
western Colorado, eastern Utah, northeastern Arizona, northwestern New
Mexico, Wyoming, and Texas (NRC80). The majority of the uranium deposits
are sandstone deposits. Ore deposits generally occur in layers that lie
nearly parallel to the host beds. Ore bodies are generally irregular in
shape and size, ranging from small masses measuring only a few meters in
width and length to masses tens of meters thick, hundreds of meters wide,
and thousands of meters long. The volumes of the ore bodies range from a
few hundred to several million tons. The extreme variation of uranium
ore bodies relative to size, shape, depth, continuity, physical proper-
ties, geologic structure, grade, and groundwater condition results in
each underground uranium mine being relatively unique in its layout and
mining method. Furthermore, the configuration of a specific underground
uranium mine changes continuously as the operation progresses.
Currently, the three techniques for mining uranium are open-pit min-
ing, in situ leaching, and underground mining. Underground mining is the
principal method for recovery of uranium ores lying more than 150 meters
(500 ft) below the surface. Considerable expense is involved in excava-
tion; therefore, development of the mine is governed by the geometry of
the ore body as a function of ore grade. Development of an underground
mine proceeds by the blasting and/or excavation of a wall face. Mine
ventilation is necessary to provide fresh air to the miners to keep the
radon-222 decay product concentrations in conformance with MSHA regula-
tory requirements (see Section 1.3). Usually, no effort is made to con-
trol radon-222 emissions from mine wall surfaces by the use of coatings
or to remove radon-222 from the air by physical or chemical means. Some
effort is expended, however, to confine high concentrations of radon-222
in the worked-out inactive portions of mines by sealing off or bulkhead-
ing that section (NRC80). It is frequently necessary to exhaust air from
the sealed-off portion of the mine to the surface to maintain a slight
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negative pressure relative to the active working areas. Maintaining this
slight negative pressure minimizes leakage of contaminated air into the
active mine areas.
2.2
Process Description
The choice between underground and open-pit mining
of economics. Several factors influence the economics,
of machine costs to labor costs, ore cut-off grade, and
body.
is primarily one
such as the ratio
depth of the ore
2.2.1
Underground Uranium Mining
Underground uranium mining is usually carried out by a modified room
and pillar method. A schematic of a hypothetical underground shaft mine
is shown in Figure 2-1. The sequential activities in the development of
such a mine are listed below and described in the following subsections.
o
o
Main shaft sinking
Haulage drifting
Ventilation shaft sinking
Long-hole exploration
Raising to a stope level
Stope development
Stope extraction
n
o
o
o
o
Some mines follow the ore vein, and access to the vein is gained via
an incline or declined drift instead of a shaft.
Main Shaft Sinking
Depending on depth and geologic conditions, either vertical or
inclined shafts may be used to access the ore. As deeper deposits are
developed, however, the trend is toward the use of vertical shafts.
These range in depth from a few hundred feet to the present-day maximum
of about 900 meters (3,000 feet).
Modern production shafts are circular and concrete-lined. Inside
diameters range from 3 to 5 meters (10 to 16 feet), depending on produc-
tion requirements. Ore and waste ore are hoisted in two skips operating
in balance. Utility lines (electric cables, water lines, and compressed
air pipes) are attached to the shaft wall.
The main or production shaft generally extends 30 meters (100 feet)
or more below the production level to accommodate spillage cleanup and
sump capacity. Normally, it is located outside the ore perimeter or
horizon (EPA80).
Haulage Drifts
Following the construction of the main shaft, haulage drifts are
extended out below the anticipated ore horizons. They are usually driven
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VENT HOl.E
~
PUMP RELAV
STATION
EXPLOSIVES
SUPPLIES
c1I~
ORE BODY
ORE BODY
.. Q=
::0
...~
ORE BODY
-- 4=
EXPLOSIVES
> ~
or
LUNCH I
ROOM or SHOP
:ld'~
:0
~
HAULAGE DRIFT
~
EXPLOSIVES
\I
=C>
-
-
LONGHOLE
DRILLING
HAULAGE
DRIFT
DRIVING
SHAFT SUMP
Figure 2-1.
Schematic diagram of an underground uranium mine (EPA80).
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about 2.5 meters by 2.7 meters (8 feet by 9 feet), with a 1 percent
gradient to favor both the loaded haulage and mine drainage.
Ventilation Shaft Sinking
Adequate ventilation is needed in all underground mines to provide a
supply of fresh air to the mine workers. In modern uranium mines, sepa-
rate ventilation shafts are sunk at strategic points to ventilate the
mine exhaust air. The main shaft is used as the intake for fresh air.
Long-Hole Exploration
Following haulage drift development, a series of exploratory long
holes are drilled upward and outward from the haulage drift to provide
better delineation of the ore bodies with respect to thickness, grade,
elevation, and dip or roll. The drilling is normally done in a fan-
shaped pattern. The angle, depth, and number of holes per fan may vary.
Raises to Stope Level
Raises are openings established between the haulage drift and ore
horizons to provide access for men, materials, fresh air, broken ore, and
exhaust air. They are generally about 4 feet in diameter and steel-
lined.
Stope Development and Extraction
During the planning for the extraction of an ore deposit. the ore
bodies are divided into suitably sized blocks that can be mined conven-
iently as working units. These are known as stopes. The size and shape
of a stope will depend on the ore body geometry. its dimensions, and the
mining method (EPA80).
The ore in a stope is usually removed in two stages, the develop-
ment stage and the extraction stage. In the stope development stage, a
drift network is developed within the ore body to provide access to all
portions of it. As much as 30 to 35 percent of the total ore may be
removed during the development stage. All of the remaining minable ore
is removed during the stope extraction stage.
The
to place
geology,
presence
stoping method varies widely from mine to mine, and even place
within the same mine. It depends on the ore body geometry and
the distribution of the ore, the nature of the ground, and the
of water.
A common method used in stoping relatively thin, flat, or gently
dipping ore bodies is the "modified room-and-pillar" method. In this
stoping method, a network of development drifts is driven in the ore body
to produce a series of pillars, which are mined during the extraction
stage. Normally the drifts are 2 meters by 2 meters (6 feet by 6 feet)
and the pillars 12 meters by 12 meters (40 feet by 40 feet). When the
drift network has been completed, the stope is ready for extraction;
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however. a developed stope sometimes may not be extracted until 6 months
or even a year later. The extraction usually begins from the farthest
end of the mine and proceeds toward the ore pass. As the pillars are
removed. the roof is sometimes allowed to cave in if the area is not
below the water table. Sometimes pillars of low-grade ore may be left
behind to control subsidence.
2.2.2
O~e Handling
Ore extraction involves drilling out a blasting round. loading the
explosives. and blasting. in that order. In shaft type mines. the re-
sulting loose ore is moved to the nearest stope exit. where it is hauled
along development drifts to vertical raises and gravity-fed to the haul-
age way. From there. it is transported to the main shaft for hoisting to
the surface. In single ore horizon mines. ore is hauled out at the same
elevation as the ore body. The haulage may be a part of the worked-out
ore area. The ore is maintained in a stockpile near the mine surface.
It is then usually transported to the mill and blended (Ja80 and Br84).
2.2.3
Ventilation Techniques
Adequate ventilation is needed in all underground mining to supply
fresh air to the mine and to flush out contaminated air. In underground
uranium mining. the need for adequate ventilation is even more critical
for the dilution and removal of mine air contaminated with radon-222 and
its decay products. The layout and mining plan of each underground
uranium mine is unique; therefore. each ventilation system is also unique
(EPA80).
In general. a parallel ventilation system is preferred to a series
system because air residence time and mine resistance to air flow are
less. Other ventilation systems that could be used include a blowing
system. an exhaust system. or a combination of the two (push-pull)
(Ja80).
The ventilation system usually consists of a primary system and
several secondary systems. The primary system includes the main intake
airway. fresh airways. exhaust air drifts. and an exhaust ventilation
shaft. Fans are used on either the intake shaft or the exhaust shaft.
Positive-pressure ventilation is created in the primary system by using
forced-draft fans at the ground surface. and negative pressure is created
by using exhaust fans. The production shaft and haulage drifts are com-
monly used as fresh-air intakes and airways. A large mine may have more
than one shaft for fresh-air intake and a combination of forced-draft and
exhaust fans at different vent shafts (EPA80).
Adequate ventilation typically requires about one vent hole for each
28.300 cubic meters (million cubic feet) of active mine volume. The ven-
tilation air requirements vary from mine to mine. In a recent Battelle
study of 13 mines. total mine ventilation ranged from 75 to 330 mS/s
(158.000 to 706.000 ft3/min) (B184).
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A secondary system, sometimes called "booster" or "auxiliary" sys-
tem, consists of fans and vent tubing to redirect portions of the primary
air supply to specific working areas that are not on the main ventilation
system. These systems utilize small fans (5-25 HP), which usually push
air to the working areas through flexible tubing.
In newer mines, exhaust air from working areas contaminated with
radon-222 is collected into exhaust drifts and routed directly to the
exhaust shaft. In older mines, however, radon-222-contaminated air from
a working area is often discharged into the next working area or into the
primary air system. In older mines that operate under positive ventila-
tion, exhaust air is usually allowed to escape by a convenient route,
which might be the main access shaft. Modern practice in underground
uranium mining, however, dictates that radon-222-contaminated exhaust air
be routed away through exhaust drifts that are separate from haulage
drifts and shafts. More and more mines are exercising great care to
separate exhaust airways and are taking steps to prevent exhaust air from
contaminating the fresh air supply (EPA80).
Vent holes can exit the ground in either a horizontal or vertical
position (see Figure 2-2). Previously, horizontal vent pipes were used
to direct the moisture-laden gas stream away from the electrical equip-
ment located near the vent. Cascading of the condensed water vapor and
ice during colder months frequently damaged the equipment. The practice
of lining the vent pipe with steel and providing piped weepholes to
control water seepage has enabled vertical discharges to be used without
damage to the equipment.
2.3
Economic Profile of the Underground Mining Industry
An overview of the underground uranium mining industry is presented
here. A more detailed profile of this industry was developed for EPA by
Jack Faucett Associates (JF85).
2.3.1
Domestic Uranium Production
The uranium industry has changed substantially since its beginning
in the 1940's. Prior to the mid-1960's, the Federal Government owned a
significant amount of the uranium in the United States, and military use
was virtually the only source of demand for uranium (DOE84d). During the
1960's, however, the commercial nuclear power industry began to emerge as
a result of the passage of the Private Ownership of Special Nuclear
Materials Act, Public Law 88-489, 1964. At the same time the Government
began to withdraw from the market and draw upon its own stockpiles to
meet its uranium requirements. Thus, the uranium industry entered a
transitional period in which commercial nuclear powerplants became the
dominant souce of demand and the Government moved from its historical
position as sole buyer and, in fact, made a complete exit from the market
(DOE84a).
In 1966, under provisions of the Atomic Energy Act, the Atomic
Energy Commission put into effect a complete embargo of foreign uranium
for domestic use. The purpose of this law was to ensure the development
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FAN
GROUND SURFACE
N
I
"
VENTILATION SHAFTS
VERTICAL VENT
HORIZONTAL VENT
Figure 2-2.
FAN
Ventilation shaft vertical and horizontal exhaust vents.

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of a domestic uranium industry with sufficient capacity to meet domestic
uranium requirements. The restriction was designed to encourage growth
in a period of low prices, limited demand, growing imports, and high
expectations of future demand.
Nevertheless, the industry remained relatively dormant from 1966 to
1975 because of the cessation of Government purchases and the still
limited uranium demand from nuclear powerplants. After 1975, rising oil
prices and the desire to develop national energy self-sufficiency created
expectations of a large growth in nuclear power capacity. Long-term
contract agreements between producers and utilities proliferated as util-
ities sought to obtain secure supplies of uranium (DOE83a). The develop-
ment of long-term contracts, along with rapid uranium price rises, led
domestic producers to expand capacity substantially, and between 1975 and
1980 production, employment, exploration expenditures, and milling and
mining investment increased steadily. By 1980, 34 firms were operating
uranium mines and 147 were engaged in uranium exploration. The resulting
growth in supply capability was not matched by the expected increase in
demand; as a result, the domestic uranium industry has steadily declined
since 1980. The excess supply has led to sharp contraction within the
domestic production industry.
The historical production data in Table 2-1 indicate the trends in
uranium production in the United States between 1966 and 1983. Tonnage
increased sharply from 1975 to 1980, but declined steeply between 1980
and 1983. The average grade of processed uranium ore also dropped sub-
stantially between 1966 and 1982 as producers depleted high-grade, easily
obtainable reserves and turned to lower-grade uranium deposits to meet
contract obligations. According to industry sources, the 0.014 percent
rise in ore grade from 1981 to 1983 reflects "high-grading" (or the
mining of only high-grade ores to minimize unit production costs).*
Although "high-grading" enables mines to stay open now, it shortens mine
life in the long run by effectively rendering lower-grade ores economi-
cally infeasible to mine. Despite such efforts to remain competitive,
some domestic suppliers have ceased production.
Many mines have either shut down permanently or have been placed on
standby (see Appendix A). Some suppliers are purchasing foreign uranium
and utility uranium inventories on the spot market to meet contract com-
mitments. Such "secondary transactions are a new phenomenon in the ura-
nium industry, but they are expected to continue unless price increases
encourage an increase in domestic production. Currently, oversupply has
driven the spot market price for uranium to $15.50 per pound, its lowest
point since 1973 (NUEXC084). At the same time, production costs are
estimated to be at a high; the U.S. average is about $35.00 per pound.**
*
**
Industry information.

Spot market prices are estimates of the price at which transactions
for immediate delivery of uranium could be concluded. Contract
prices are price agreements for future deliveries of uranium.
2-8

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Table 2-1. Historical trends in U.S. uranium production
 (DOE84a, DOE80-83) 
  Grade of ore
Year Short tons of UgOs (% UgOs)
1966 10,589 0.229
1967 11,253 0.203
1968 12,368 0.195
1969 11,609 0.208
1970 12,905 0.202
1971 12,273 0.205
1972 12,900 0.213
1973 13,235 0.208
1974 11,528 0.176
1975 11 ,600 0.170
1976 12,747 0.157
1977 14,939 0.154
1978 18,486 0.131
1979 18,736 0.105
1980 21,852 0.119
1981 19,237 0.114
1982 13,434 0.119
1983 10,579 0.128
As a result of this situation, domestic production, once a growing
and profitable segment of the economy, has fallen victim to declining
demand and competition from foreign sources. The number of domestic
production sources (including open-pit mines, underground mines, and
other sources) fell from a peak of 432 in 1979 to only 135 in 1983. The
decline continued in 1984, and as of November 1984, only 26 underground
mines and 14 open-pit mines were operating.
2-9

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The decline in employment in all areas of the U.S. uranium industry
since 1979 is evident in the data shown in Table 2-2. Exploration em-
ployment has dropped the most dramatically; the 1983 employment in this
area was less than 10 percent of that in 1979. In 1983, milling employ-
ment (which is closely tied to uranium mining) was less than one-half
1979 employment and mining employment was about 25 percent. The tremen-
dous drop in exploration employment illustrates producer expectations of
little need for capacity expansion, whereas the declines in mining and
milling reflect the large number of shutdowns and closures. Since 1978
the total labor force has been reduced by about 75 percent, or 16,000
workers.
Table 2-2. Employment in the U.S. uranium industry, 1979-1983
   (DOE80-83, 8~b~     
   [person years a]     
     Year   
   1979 1980 1981 1982 1983
Mining         
Underground 5,706 5,037 3,518 2,150 1,109
Open-pit  3,782 3,414 1,857 1,365 755
In situ/byproduct 1,704 1,530 1,536 1,185 929
Other a  3,267 3,317 2,098 1,679 930
Subtotal mining 14,459 13,298 9,009 6,379 3,723
Milling   3,236 3,251 2,367 1,956 1,518
Exploration  4,066 3,370 2,300 769 374
Total   21,761 19,919 13,676 9,104 5,615
(a) Includes technical and supervisory employees.   
The decline in capital expenditures since 1979 has also been dramat-
ic. In 1983, total industry capital expenditures were only $67 million,
compared with $801 million in 1979 (current dollars). Mining and milling
investment ($30 million) was at a 10-year low as a result of the current
excess capacity within the industry. In the absence of a turnaround in
market conditions, the low levels of expenditure are likely to persist.
Expenditures planned by uranium firms for 1984 and 1985 are approximately
the same as those for 1983. Capital expenditures for 1979 to 1983 and
planned expenditures for 1984 and 1985 are presented in Table 2-3.
2-10

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   Table 2-3. Capital expenditures in the U.S. uranium industry (DOE83b)
      (millions of current dollars)   
  Exploration   Mining  Milling Total
   Number of    Number of  Number of 
 Year Expenditures companies Expenditures companies Expenditures companies Expenditures
 Actual          
 1979 316 164 282  26 203 26 801
 1980 267 147 273  34 242 27 782
 1981 145 107 212  29 59 22 416
N           
' 1982 74 86  81  23 11 15 166
......  
......           
 1983 37 77  27  17 3 14 67
 Planned          
 1984 32 63  27  17 12 16 71
 1985 24 45  31  13 5 10 60

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A number of negative forces have combined to cause the current state
of the industry. Perhaps the most important of these is that the growth
in electricity generated by nuclear plants and the expansion of nuclear
power capacity have been much slower than was forecasted in the mid-
1970's, partially because of numerous construction delays and cancella-
tions. At the end of 1983, 80 nuclear reactors were licensed to operate
in the United States, totaling 64.4 gigawatts of generating capacity
(DOE84c).
The status of U.S. nuclear powerplants as of December 31, 1983, is
shown in Table 2-4. The long lead times associated with the ordering,
construction, and permitting of nuclear powerplants make it extremely
unlikely that any additional orders for new nuclear plants will result in
operable capacity before 1996. Furthermore, 10 of the 58 plants in the
construction pipeline as of December 31, 1983, were cancelled in the
first 10 months of 1984.
Imports currently playa major role in the U.S. -uranium market. The
import restrictions in effect from 1964 to 1977 underwent a phased with-
drawal, and as of 1984, no import limitations were any longer imposed.*
The result has been a steady increase in uranium imports from nations
possessing high-grade (and thus low-cost) uranium deposits. In 1977,
only 4.7 percent of the uranium delivered to DOE enrichment plants by
domestic utilities was of foreign origin; whereas in 1983, foreign sources
provided 16.9 percent of total deliveries (DOE84a). A growing portion of
utility requirements are expected to be supplied by foreign-origin ura-
nium during the second half of this decade.
. A third factor contributing to the current downturn in the uranium
industry is the large inventory levels held by both producers and util-
ities. Utilities, anticipating a growing need for uranium, entered into
long-term contracts to purchase large amounts of domestically-produced
uranium. As actual needs fell short of expe~ted needs because of nuclear
powerplant construction delays and cancellations, large inventories began
to accumulate. These inventory supplies, currently estimated to cover
utility requirements for four to five years, adversely affect suppliers
in two ways. First, they may extend the downturn in uranium demand for
several years by decreasing the need for utilities to enter into new
contracts. Second, high interest rates have increased inventory holding
costs; thus, some utilities are contributing to the current excess supply
by offering inventory stocks for sale on the spot market.
2.3.2
The Underground Uranium Mining Industry
As noted in the previous section, domestic uranium is produced by a
number of different mining techniques. Conventional mining, either
open-pit or underground, has historically accounted for over 90 percent
of U.S. production; however, in recent years, in situ leaching, heap
*
As of January 1985, there were no bills pending in either the U.S.
House of Representatives or the U.S. Senate that would reimpose import
restrictions.
2-12
~

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Table 2-4.
Status of U.S. nuclear powerplants as of
December 31, 1983 (DOE84c)
Status
Number of
reactors
Net design
capacity
(MWe)
Operable
In commercial operation
In power ascension
Subtotal
76
4
80
60,200(a)

4,200
64,400
In construction pipeline
In low-power testing
Under construction
3
3,400
More than 50 percent complete
30 to 50 percent complete
Less than 30 percent complete
37

4

2
40,400
4.600
2,400
11 , 700
2,200
64,700
Indefinitely deferred
Reactors on order
Subtotal
10

2

58
TOTAL
138
129,100
(a)
Includes Three Mile Island 1 (819 MWe). which has
cense but is in an extended shutdown mode. Three
Dresden 1 are not included.
an operating li-
Mile Island 2 and
leaching,
tanto In
estimated
the years
and copper byproduct methods have become increasingly impor-
1983, the conventional mining share of production fell to an
70 percent.* Domestic production by type of mining method for
1979 to 1983 is presented in Table 2-5.
Underground mines, the leading source of domestic production, ac-
counted for an estimated 39 percent of domestic production in 1983.
Almost half the underground mines operating in November 1984 were located
in New Mexico; the rest were divided among four states. Of the 26 then
active mines, 12 were in New Mexico, 5 in Colorado, 4 in Wyoming, 3 in
Utah, and 2 in Arizona. In January 1985, Kerr-McGee Corporation announced
that the nine underground mines owned by its Quivira Mining subsidiary
are soon to cease operations. This will reduce the number of underground
mines. Quivira's mines are all in New Mexico.
*
Unofficial DOE estimate.
2-13

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Table 2-5.
Uranium production by mining method (DOE80-83)
 Underground Open pit  Other(a)
Year 1000 tons % of total 1000 tons % of total 1000 tons % of total
1979 6.3 30 9.4 45 5.0 25
1980 9.6 41 10.4 45 3.3 14
1981 8.6 43 7.0 36 4.1 21
1982 6.3 46 3.8 29 3.3 25
1983(b) 4.1 39 3.3 31 3.2 30
Note:
The production totals in this table are not strictly comparable
with those in Table 2-1 because the underground and open-pit
production represents the production in ore before mill process-
ing, whereas the production in Table 2-1 represents uranium ob-
tained from ore, as reported by mills.
(a) Includes production from solution mining, byproduct, heap leaching,
mine water, and low-grade stockpiles.

(b) Figures for 1983 are unofficial DOE estimates.
2-14

-------
Key statistics of underground uranium mining are presented in Table
2-6. Between 1979 and 1983. the number of operating underground mines
dropped from 300 to 95. and employment fell from 5709 to 1109 person-
years. Although U30a production and raw ore production are both down.
raw ore production showed a larger decrease because of a rise in average
ore grade. The underground mine production of average ore grade has
nearly doubled since 1979 because of the shutdown of low-grade mines and
high-grading practices at operating mines.
Appendix A lists the underground mines in operation as of October
1984 (DOL84). The 26 active mines were operated by 12 firms. Although
production data from individual mines are not available. employment at
each mine is reported and provides some indication of the level of mining
activity. Five of the mines have less than 10 employees. and another
eight have 25 or less employees. The shutdown of all Kerr-McGee under-
ground mines will have a significant impact on employment and production.
In 1983. Kerr-McGee reported 1156 short tons of uranium production (U30a)
from underground mines. or approximately 24 percent of all 1983 domestic
underground mine production.* Other companies reporting underground mine
production in their 1983 annual reports were Homestake. Rio Algom. and
Wester Nuclear. with totals of 578. 167. and 18 short tons. respectively.
Thus these four producers accounted for 47 percent of estimated 1983
underground mine production.
2.3.3
Forecasts of Domestic Production
Annual forecasts of the total production of U30a from domestic
sources for 1985 through 1990 are presented in this section. The fore-
casts are based on the results of the low electricity demand case of the
DOE viability study (DOE84d); however. adjustments were made to reflect
the most likely level of imports, rather than the severely constrained
import scenarios of that study. The share of total unfilled delivery
requirements to be supplied by domestic producers is projected by assum-
ing a 37.5 percent import share through 1990. Also unlike the DOE study.
total unfilled requirements for delivery to the DOE enrichment facility
are projected under the assumption that the enrichment facility will
continue operation at the current level of efficiency of U-235 recovery.
Total demand from domestic sources is then calculated as the sum of
current domestic contracts for delivery of domestically produced U30a.
the assumed domestic share of total unfilled delivery requirements. and
current export contract commitments. The results of this analysis indi-
cate that total domestic production of U30a is expected to fall from
10.000 tons in 1984 to 7600 tons in 1990.
Virtually all uranium produced by U.S. mine operators is consumed by
one sector. the nuclear power industry. Therefore. forecasts of domestic
production depend largely on the long-term status of this industry. The
requirements of nuclear powerplants currently in operation may be consid-
ered a well-established. baseline demand; thus. uranium needs of opera-
ting powerplants may be projected with high precision. Forecasts of
*
Kerr-McGee 1983 Annual Report and 10-K Form.
2-15

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Table 2-6.
Underground uranium mining statistics (DOE80-83)
  Ore delivered     
  to mills U30a production Average % of total Number Employment
 Year (1000 tons) (1000 tons) grade (96) U30a production of mines (pe rsons-years)
 1Q79 5356 6.3 0.118 30 300 5706
 1980 6351 9.6 0.151 41 303 5037
 1981 5229 8.6 0.164 43 167 3518
 1982 2809 6.3 0.224 46 139 2150
 1983 NA (a) 4.1 NA 39(b) 95 1109
N 1984 NA NA NA NA 26(c) NA
,
I-'       
0\       
(a) NA =
(b)
(c)
not available.
1983 production and number of mines are unofficial DOE estimates.
Operating underground mines as of November 1984 (DOL84).

-------
requirements of nuclear powerplants currently under construction are
highly speculative, however. Our base-case analysis assumes that no
plants currently less than 30 percent complete will be on line before
1990. This and other assumptions used in this analysis are equivalent to
those used for the low electricity demand case in the DOE analysis. In
addition to the uncertainty surrounding the demand for enriched uranium
for the nuclear power industry, several other factors complicate the
forecast Qf domestic demand for uranium ore. Small changes in the effi-
ciency of operation of the DOE enrichment facility* can lead to large
changes in required UsOa deliveries for enrichment. The likelihood of a
change in the operating efficiency of the enrichment facility depends on
a second uncertain factor--the continued availability of cheap imported
ore from Canada, Australia, and South Africa. If imports were to be
curtailed by Government action intended to protect the domestic uranium
mining and milling industries, this could lead to a significant rise in
the price of UsOa delivered to the enrichment facility and shift the
optimal tails assay level downward. The lower tails assay level would be
desirable, as it would reduce the amount of UsOa required for delivery.
The magnitude of this effect can be quite substantial.
In the absence of import constraints, the import share of total
unfilled requirements is expected to rise because of the significantly
lower price of the imports. In total, imports now account for more than
30 percent of uranium deliveries. The requirements for uranium import
commitment dependency under Public Law 97-415 make it unlikely that the
import share will be permitted to rise significantly above today's level.
If the projected import share should rise to 37.5 percent, the law re-
quires that the U.S. International Trade Commission initiate an investi-
gation under Section 201 of the 1974 Trade Act (19 U.S.C. 2251). It is
unlikely that imports in excess of 37.5 percent will be permitted. For
this analysis, the import share of unfilled delivery requirements is
assumed to peak at 37.5 percent and remain at this level. Under this
import assumption, unfilled delivery requirements from domestic sources
are projected to rise to a level of 3300 tons UsOa per year by 1989,
which yields cumulative unfilled requirements from domestic sources of
9200 tons UsOa by 1990.
The projected level of domestic demand in the base case is below the
production potential of currently existing mines that have low cost
reserves. Therefore, it is unlikely that any new underground mines will
be opened during the remainder of this decade.
Domestic requirements may be filled by production from underground
mines, open-pit mines, or from several other sources including solution
mining, byproduct production, heap leaching, mine-water recovery, and
*
The operating efficiency of the enrichment facility is determined by
assaying the concentration of U-235 in the tailings discarded after
enrichment. The facility currently operates at a tails assay level
of 0.25 percent. A lower tails assay level indicates recovery of a
greater percent of the U-235 originally present in the input feed,
and hence, greater efficiency of enrichment.

2-17

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low-grade stockpiles. In Table 2-7, production by each source is indexed
to the most recent peak production level, which occurred in 1980 for
underground and open-pit mines. (The year 1979 is apparently a peak
production year for other sources; however, data was not available for
years preceding 1979.) In recent years, underground mining has suffered
a reversal in its market share trend, which peaked in 1982. This loss of
market share will be accelerated by the most recently-announced closing
of the Kerr-McGee mines, which produced 1100 tons of UsOa in 1983. In
the projections, this downward trend is continued, and underground mining
accounts for only 30 percent of domestic production by 1990. The projec-
tions for open-pit mining are based on a slight increase in market share
but declining production over the remainder of the decade. Other sources
are forecasted to remain roughly constant at present production levels
despite the decreasing demand, which leads to a slightly rising market
share. The projections contained in Table 2-7 are highly speculative and
are based simply on extrapolations of recent trends.
2-18

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Table 2-7.
Historic and projected U30S production, market share, and
capacity utilization index by source
   Underground   Open-pit   Other sources  Total production
 Year Annual(a) Market share(b) Index (c) Annus I Market share Index Annual Market share Index Annual Index
 Historic            
 1979 6.3 30 0.66 9.4 45  0.90 5.0 25 1.00 20.7 0.89
 1980 9.6 41 1.00 10.4 45  1.00 3.3 14 0.66 23.3 1.00
 1981 8.6 43 0.90 7.0 36  0.67 4.1 21 0.82 19.7 0.85
 1982 6.3 46 0.66 3.0 29  0.29 3.3 25 0.66 12.6 0.54
 1983 4.1 39 0.43 3.3 31  0.32 3.2 30 0.64 10.6 0.45
 Projected            
 1984 3.9 39 0.41 3.1 31  0.30 3.0 30 0.60 10.0 0.43
 1985 3.1 33 0.32 3.2 34  0.31 3.2 34 0.64 9.5 0.41
 1986 3.0 32 0.31 3.2 34  0.31 3.2 34 0.64 9.4 0.40
N  2.9 32 0.30 3.1 34  0.30 3.1 34 0.62 9.1 0.39
I 1987 
I-' 1988 3.0 32 0.31 3.2 34  0.31 3.2 34 0.64 9.4 0.40
\0 
 1989 2.8 31 0.29 3.0 34  0.29 3.1 35 0.62 8.9 0.38
 1990 2.3 30 0.24 2.6 34  0.25 2.7 36 0.54 7.6 0.33
 (a) Annual  U,Oe production (thousand tons).          
 (b) Percent of U,Oe lotal production.          
 (c)RatiO of current production to peak year production.         

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B184
Br84
DOE80-83
DOE83a
DOE83b
DOE84a
DOE84b
DOE84c
DOE84d
DOL84
EPA80
REFERENCES
Bloomster, C. H., et al., Cost Survey for Radon Daughter Con-
trol by Ventilation and Other Control Techniques, Prepared for
the Bureau of Mines by Battelle Pacific Northwest Laboratory,
Richland, Washington, Contract J021S033, 1984.
Bruno, G. A., et al., U. S. Uranium Mining Industry: Back-
ground Information on Economics and Emissions, PNL-S03S, Bat-
telle Pacific Northwest Laboratory, Richland, Washington, 1984.
Department of Energy, Grand Junction Area Office, Statistical
Data of the Uranium Industry, GJO-100, 1980-1983 editions.
Department of Energy, Energy Information Administration, World
Uranium Supply and Demand: Impact of Federal Policies, DOE/EIA-
0387, March 1983.
Department of Energy, Survey of U.S. Uranium Marketing Activity
1983, DOE/EIA-0403(83), 1983.
Department of Energy, United States Uranium Mining and Milling
Industry: A Comprehensive Review, DOE/S-0028, May 1984.
Department of Energy, Survey of United States Uranium Marketing
Activity 1983, DOE/EIA-0403(83), Energy Information Administra-
tion, August 1984.
Department of Energy, Energy Information Administration, Com-
mercial Nuclear Power 1984: Prospects for the United States
and the World, DOE/EIA-0438(84), November 1984.
Department of Energy, Domestic Uranium Mining and Milling
Industry: 1983 Viability Assessment, Pre-publication release,
December 1984.
Department of Labor, 1984 Uranium Mines Address Listing With
Workers and Employee Hours - 3rd Quarter, Mine Safety and
Health Administration, Health and Safety Analysis Center,
Denver, Colorado, November 21, 1984.
U.S. Environmental Protection Agency, Technical Assessment of
Radon-222 Control Technology for Underground Uranium Mines,
ORP/TAD-80-7, 1980.
2-20

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Ja80
JF85
NRC80
NUEXC084
REFERENCES (continued)
Jackson, P.O., et al., An Investigation of Radon-222 Emissions
From Underground Uranium Mines, Progress Report 2. PNL-3262.
Battelle Pacific Northwest Laboratory. Richland. Washington,
1980.
Jack Faucett Associates. Economic Profile of the Uranium Mining
Industry. January 1985.
U.S. Nuclear Regulatory Commission. Radon Releases From Uranium
Mining and Milling and Their Calculated Health Effects. NUREG-
0757. 1980.
NUEXCO. Monthly Report on the Nuclear Fuel Market. December
1984.
2-21

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Chapter 3:
ATMOSPHERIC EMISSION OF RADON-222
3. 1
Theoretical Considerations
3.1.1
Origin and Generation of Radon-222
Uranium ore contains both uranium and the decay products of uranium.
In nature, uranium is about 99.3 percent uranium-238. Therefore, it is
the decay products of uranium-238, shown in Figure 3-1, that governs the
radioactive content of the ore and the production of radon-222 (NRC81).
This figure also shows the half-life and the principal decay mode of each
radionuclide.
As Figure 3-1 indicates, radium-226 is the direct parent of radon-
222, which is the only member of the decay chain that is a gas. Further-
more, radon-222 is a noble gas; therefore, it does not usually combine
with. other elements to form nongaseous compounds. As a gas, radon-222
can be released to the atmosphere if it escapes the mineral matrix that
contains its parent, radium-226.
Almost all natural soils contain some uranium-238, which ultimately
decays to radon-222. When uranium ore lies undisturbed underground, only
a very small fraction (if any) of the radon-222 it produces escapes to
the atmosphere. Radon-222 has a half-life of only 3.8 days; therefore,
most radon-222 that is generated more than a few meters below the surface
decays into nongaseous radionuclides before it can migrate through the
soil and escape into the atmosphere. When uranium ore is mined, however,
the constant exposure of previously undisturbed uranium ore allows radon-
222 to escape into the mine atmosphere.
Underground uranium mines have ventilation shafts installed at
appropriate distances along the ore deposit. A large mine will usually
have several ventilation shafts; some mines have as many as 14 vents.
Mine ventilation is necessary to reduce concentrations of radon-222 and
radon-222 decay products in the mine air to which miners are exposed.
Such ventilation is usually provided by high-capacity (up to 200,000 cfm)
exhaust fans that remove air from the mine through the ventilation shafts
and discharge it at or just above ground level. All radon-222 released
from underground mine surfaces will either be contained in the ventila-
tion exhaust or it will decay in underground airways because of stagna-
tion. Radon-222 also can be released by the ore and subore stockpiles on
the surface and by' small amounts of waste that are brought to the surface
and accumulated during the life of the mine (EPA84).
3-1

-------
~238
Ci.,y
Rn-222
S,y
Bi-210
Ci.,y
9
4.5 x 10 y
Ci.,y
4
7.7 x 10 y
3
1. 6 x 10 y
Ci.
3.82 d
Ci.,y
1 -4
. 64 x 10 s
22.3 Y
S
5.01 d
Fi gure 3-1.
111- 234
S,y
Pa-234
24.1 d
s,y
1.17 m
R>-218
Ci.
P1r214 .
3.05 m
S,Y
26.8 m
Po-210
Ci.,y
138.4 d
Uranium-238 decay chain
3-2

-------
3.1.2
Factors Affecting Emissions of Radon-222 to Air
Radon-222 emissions from ventilation exhausts, although highly vari-
able, are directly related to the amount of radon-222 emanated within the
mine. The volume of ventilation air exhausted from an individual mine is
not believed to have a significant effect on total radon-222 emissions.
Although the concentration (pCi/liter) of radon-222 may vary as a func-
tion of exhaust volume, the total amount discharged is much more depend-
ent on radon-222 emanation within the mine.
A number of interrelated factors affect the rate and/or amount of
radon-222 emanation within the mine atmosphere. These include ore grade,
mining practices, production rate, age of the mine, size of active working
area, and several other variables.
Mining practices (e.g., rate of advance and size of broken ore) also
influence the rate of radon-222 emanation. About 5 percent of the avail-
able radon-222 in the rock is released at the instant of blasting (Th74).
Thus, the more frequently blasting occurs, which would be indicative of a
rapid advance in the mining area, the greater the release rate of avail-
able radon-222. Radon-222 emanation from broken ore increases with
greater fragmentation of the ore. Overblasting that opens cracks extend-
ing farther into the ore zone further increases radon-222 emanation from
the fractured rock.
Measurement programs at underground mines (Ja79 and Ja80) indicate
that the amount of radon-222 exhausted with ventilation air is more
directly related to the total surface area of underground workings being
ventilated than to daily production rates. The total underground surface
area is generally proportional to the total cumulative amount of ore
extracted during the lifetime of the mine. This is logical because the
uranium content of the rock surface in the mined-out areas of the mine is
not zero; rather, it varies up to the economic cutoff grade for mining.
The total area of exposed mine surfaces is many times that of a working
face from which ore is being extracted, especially for a mine that has
been in operation for several years. Therefore, radon-222 emission rates
tend to increase with the age of the mine because more surface area has
become exposed by subsequent mining.
3.1. 3
Difficulties in Estimating Radon-222 Emissions
Conceptually, development of a "model underground mine" that could
be used to predict or estimate annual radon-222 emissions as a function
of some explanatory variable (e.g., ore grade, production rate) would be
desirable. As discussed in the previous subsection, however, many known
variables affect radon-222 emissions. One of the most important varia-
bles appears to be that of exposed mine surface area. Thus, instead of a
"model underground mine," another method for estimating emissions would
be to establish a relationship between mine surface area and amount of
ore mined and then a further correlation between mine area exposed and
radon-222 emitted. In principle, this approach appears feasible; in
practice, however, it has not proven to be realistic because of a lack of
information. The kind of information necessary to model exposed mine
3-3

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surface area and to estimate the lifetimes of current mines including
when new mines will be opened is not currently available.
An alternative approach for estimating total radon-222 emissions is
to measure radon-222 releases from operating mines and for long periods
so that the sample population represents a significant fraction of the
total production of UgOs from underground mines. Assuming the sample
population is representative of the industry, an average emission factor
can be calculated that relates radon-222 emission to UgOS production.
This is the approach that EPA has selected in forecasting total radon-222
emissions from underground mines. This approach and its limitations are
discussed in the following subsections.
3.2
Radon-222 Emissions
3.2.1
Radon-222 Sources
Radon-222 emissions from underground uranium mines originate from
aboveground sources or underground sources. Aboveground sources include
waste piles, ore storage piles, and discharged mine water. Underground
sources include radon-222 emanation from wall rock, groundwater, and
broken ore. Radon-222 emissions from underground sources are released to
the atmosphere through mine ventilation systems. In 1978 and 1979, the
U.S Nuclear Regulatory Commission (NRC) contracted Battelle/Pacific
Northwest Laboratory (PNL) to quantify radon-222 emissions from under-
ground uranium mines. In addition, Battelle/PNL investigated correla-
tions between a mine's annual radon-222 emissions and specific mine
characteristics (Ja79 and Ja80). The data base and correlations that
Battelle/PNL established during this project currently comprise the bulk
of EPA's radon-222 emission data.
3.2.2
Measured Emissions
The current EPA data base on radon-222 emissions from underground
uranium mines consists of annual radon-222 emission measurements from 27
mines. This data base has a number of limitations. First, the emission
measurements were made 7 and 8. years ago. Current emission data are not
directly quantified; therefore, these estimates may not adequately re-
flect the effects of mine closures, production decreas~s, and changes in
mining practices that have occurred since the measurements were made.
Second, for estimation of current and future total annual emissions,
EPA's data base must be assumed to be reasonably representative of the
entire underground uranium mining industry. While this was probably true
in 1978-1979, it is uncertain whether the 27 previous mines sampled are
currently representative of mining with respect to mine age, cumulative
ore produced, ore grades, and mining practices. A third limitation con-
cerns calculating a mine's annual radon-222 emissions. Annual radon-222
emissions are calculated by extrapolating short-term sampling results
over a I-year period. This limitation may not be significant because
continuous monitors were used to record radon-222 emissions for periods
up to 1 month at four mine vent locations. Except for diurnal radon-222
emission peaks (usually 1.2 to 1.5 times the average emission, which
3-4

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corresponded to decreases in barometric pressure), individual mine vent
emissions were found to be relatively constant.
The following discussion focuses on radon-222 emissions from under-
ground sources (i.e., mine vent emissions). Mine vent radon-222 emissions
greatly exceed the radon-222 emissions from all other sources. Batte11e/
PNL determined that aboveground emissions constitute only between 2 and 3
percent of a mine's total radon-222 emissions. The overall uncertainty
of the total mine emission measurements is +30 to -18 percent (Ja80).
Consequently, contributions from aboveground sources to total radon-222
emissions are insignificant when compared with the overall uncertainty in
estimated total emissions.
For purposes of this document, mine vent radon-222 emissions are
discussed and tabulated on three bases: 1) curies per year (Ci/y),
2) curies per short ton of U30a produced annually (Ci/ton U30a), and
3) curies per year per short ton of cumulative ore produced (Ci/ton-y).
Table 3-1 summarizes radon-222 emission data from 27 underground
uranium mines that were sampled by PNL in 1978-1979. The vent emissions
listed in this table represent the sum of measured emissions from as many
as 14 individual mine vents at some mines. Radon-222 emissions varied
significantly among individual vents from a common mine ventilation sys-
tem. Therefore, all vents from a common system were sampled simultane-
ously, and the radon-222 emissions were summed to obtain total vent
emissions (Ja80).
The mine vent emissions presented in Table 3-1 do not necessarily
represent the radon-222 emissions from completely uncontrolled mines. An
undetermined (but probably significant) number of these underground
uranium mines practiced some degree of bu1kheading and backfilling during
1978 and 1979. This means that the measured emission rates already
reflect some (unknown) level of radon-222 emission control. Although it
is possible to calculate a theoretical effectiveness (see Section 6.3.3)
of a bulkhead in reducing radon-222 emissions from a bu1kheaded area, EPA
cannot conclude that this theoretical radon-222 reduction efficiency can
be applied to measured radon-222 emissions because these emission rates
do not represent uncontrolled conditions.
The 27 uranium mines listed in Table 3-1 supplied 3,900,000 out of
6,105,000 short tons of ore produced from underground uranium mines
during 1978. Consequently, this data set represents 64 percent of the
underground uranium mining industry in 1978. Overall annual radon-222
emissions, calculated by summing the 27 individual mine vent emissions
shown in Table 3-1, were estimated to be 150,000 City (Ja80). Assuming
the 27 mines constituted a representative sample of all underground
uranium mines operating at that time, total annual radon-222 emissions
from mine vents in the underground uranium mining industry in 1978 are
estimated to be 235,000 Ci/y.*
*
(6,105,000/3,900,000) X 150,000 ~ 235,000.
3-5

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Table 3-1. Summary of radon-222 emissions from
 underground mine vents (Ja80) 
  1979 1978 
Mine measurement measurement Average
identification (Ci/y) (Ci/y) (Ci/y)
A 7,400  7,400
B 4,700 4,300 4,500
C 5,200 3,900 4,600
D 3,630  3,630
E 29,800  29,800
F 9,200 9,500 9,400
G 2,150 1,460 1,800
H 15,200  15,200
I 1,690  1,690
J 7,760 8, 100 7,900
K 7,000 5,870 6,400
L 1,470 1,320 1,400
R 15,000 14,600 14,800
T 1,890  1,890
U  890  890
V 1,010  1,010
Y 17,500  17,500
Z   2,640 2,640
AA 2,100 1,490 1,800
BB 2 , 130 1,840 2,000
CC   2,120 2,120
DD   960 960
EE 6,500  6,500
FF 2,510  2,510
GG  190 146 170
HH 1,040  1,040
II  470  470
   Total for all mines 150,000
3-6

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For purposes of relating mine vent radon-222 emissions to mining
production, 9,300 short tons of UsOa were produced from the 6,105,000
short tons of ore mined. Thus, radon-222 was emitted from underground
uranium mine vents at a rate of 25.3 Ci/ton of UsOa mined.
Most of the emissions from underground uranium mines can be at-
tributed to individual mines having a cumulative ore production of at
least 100LOOO short tons. Table 3-2 presents estimated average annual
radon-222 emissions for 252 mines as a function of mine size (i.e.,
cumulative ore production). This table shows that the larger mines
(about 25 percent of the total number of mines) contribute approximately
95 percent of the total radon-222 emissions.
 Table 3-2. Mine size categories and perc~n5ages
 of the uranium industries radon-222 emissions a (BI84)
    Average 
Cumulative   emissions Emissions
ore production Number Percent per mine per size
(1,000 tons ore) of mines of mines (Ci/y) category (i.)
1,000 - 4,700 25 10 8,800 76
100 - 1,000 39 15 1,400 19
10 - 100 82 33 140 4
1 - 10 83 33 14 1
0.1 - 1 23 9 1.4 0
Totals  252 100  100
(a) Data on the number of mines and size categories are from the DOE,
Grand Junction, Colorado, as of 1/1/79.
3.2.3
Relationship of Cumulative Ore Production to Radon-222 Emissions
Concurrent with measuring radon-222 emissions in 1978 and 1979, Bat-
telle/PNL recorded mining production rates and other parameters related
to mining operations (e.g., mine water discharge rates, number of mine
vents, mine age). Correlations between radon-222 emissions and annual
UsOe production, mine age, mine surface area, cumulative ore production,
and cumulative UsOa production were investigated (Ja79 and Ja80).
Battelle/PNL attempted to derive correlations between specific mining
parameters and the mine's total annual radon-222 emission rate. Valid
correlations would provide a method of predicting radon-222 emissions
from individual mines and the entire underground uranium industry.
3-7

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Of the parameters investigated, cumulative ore production appeared
to be most directly correlated with radon-222 emissions. The cumulative
ore production of a mine has a statistically significant linear rela-
tionship with its radon-222 emissions. Table 3-3 provides data showing
the correlation between radon-222 emissions and cumulative ore production
for 15 of the previously discussed 27 mines. These radon-222 emissions
reflect both aboveground and underground sources. In most cases, total
radon-222 emissions were estimated by multiplying the mine vent emissions
by 1.025 (Ja80). Where possible, however, total emissions were calcu-
lated by using actual data obtained from mine operators. The cumulative
ore production data were furnished by the mine operators. Figure 3-2,
a graphical representation of Table 3-3, relates radon-222 emissions to
cumulative ore production (Ja80). The line shown in Figure 3-2 was
constrained to pass through the origin because it is reasonable to assume
that radon-222 emissions begin concurrently with ore production. The
slope of this line (i.e., 4.4 x 10-3 City per short ton of cumulative ore
produced) is an emission rate factor representative of the data presented
in Table 3-3. The two broken lines in Figure 3-2, with slopes of 0.57
(i.e., 0.44 + 0.13) and 0.31 (i.e., 0.44 - 0.13), establish the 95 per-
cent confidence intervals relative to the presented data. Without in-
cluding the origin as a point, the coefficient of determination (R2) is
0.53. The R2 value indicates that about one-half the variability can be
accounted for by the relationship between radon-222 emissions and cumula-
tive ore production (Ja80). Although the correlation is significant, it
emphasizes the fact that radon-222 emissions are also a function of vari-
ables other than cumulative ore production. For example, positive-pres-
sure ventilation, mine-water flow rates. bulkheading, backfilling, and
barometric pressure also affect radon-222 emissions. The R2 value may
also be confounded by the use of various levels of control techniques
(e.g., bulkheading and backfilling) by mine operators during the radon-
222 emission test periods. The use of varying levels of bulkheads during
the emission tests could account for some of the rather low values shown
in Table 3-3. At the present time, an effective model capable of accu-
rately relating radon-222 emissions to mine characteristics has not been
developed. .
3.2.4
Estimated Future Emissions
The apparent relationship between curies of radon-222 emitted and
cumulative tons of ore extracted from a mine provides a basis for approx-
imating current and future emission rates. However, such a forecasting
procedure (even with necessary assumptions specified) requires current
mining information on each active mine and also requires knowledge of
future mining trends. Necessary information includes the cumulative ore
production figures for each mine or the current radon-222 emissions, mine
age, mining practices, working days per year, expected active life of the
mine, current production rates, and all anticipated changes that may
affect each mine. By multiplying the emission rate factor of 4.4 x 10-3
Ci/ton-y by the forecasted ore production rates for each mine and adding
the resulting value to the current emission rate of the mine, future
3-8

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Table 3-3.
Correlation between radon-222 emissions and
cumulative ore production (Ja80)
   Radon-222
  Cumulative emission rate
 Radon-22t ore produc- b per cumulative
 emissions a) tion through 1978( ) ore production
Mine (Ci/y) (106 tons) (10-6 Ci/ton-y)
B 4,600 1.2 3,800
C 4.700 1.8 2,600
D 3.700 1.5 2,500
E(c) 30,000 3.9 7,700
F(c) 9.500 4.7 2,000
G(c) 2,000 0.45 4,400
H(c) 15,300 2.6 5,900
I 1,700 1.8 960
J 8,100 2.4 3,400
K 6,600 1.4 4,700
R 15.200 3.0 5,100
U 900 0.37 2,500
Vb 1,000 0.15 6,900
Y 18,000 2.4 7,500
Z+CC 4,900(d) 1.6 3.100
(a)Radon-222 in ventilation air, from mine waste piles, ore pile. and
mine water discharged at surface. Basis: 1.025 x radon-222 in
vent.

(b)Data furnished by mine operator.

(c)For these mines, the contribution of radon-222 from mine waste
and ore piles was that estimated from pile dimensions and U30a
content.

(d)Production from mines Z and CC were composited by the mine
operator. Thus. we have composited their radon-222 output for
comparison.
3-9

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       x   
 3.0 Y=AxX       /
  A .. 0 ,44 + 0 ,13       /
-       / 
>-  R-SQUARE .. 0,53     / 
u        /  
~       /   
0         
-         
-      /    
uJ 2.0        
I-   X /     
<:        
~     /     
z    }/X     ""
o        .".,.
V')       ""
V')    /    / 
~  /    ", 
uJ    ",   
z  /   ",    
0 1.0 /  /    X
c   ",     
<:  / x/      
~       
  /x ", /'      
  #~       
  /".,."" X       
  /x"" X       
  X"'X       
 0.0 2    4   6
 o     
  CUMULATIVE ORE PRODUCTION (106 tons)
 Figure 3-2. Relationship of annual radon-222 emisson rate
  to cumulativ~ ore production (Ja80).  
3-10

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annual radon-222 emissions can be predicted for each individual mine. Of
course. the total annual radon-222 emissions from underground uranium
mines for any particular year would be the sum of the emissions from all
individual mines plus the relatively small contributions of radon-222
from aboveground sources.
The extensive amounts of data necessary to estimate future emissions
on a min~-by-mine basis are currently unavailable. Therefore. EPA made
two assumptions to develop an alternative forecasting procedure: 1) that
the 27 mines included in the Battelle/PNL study (Ja80) comprise a repre-
sentative sample of all underground uranium mines with respect to emis-
sions. and 2) that the distribution of the number of active mines rela-
tive to cumulative production remains constant during the forecast pe-
riod. In other words. any incremental increase in radon-222 emissions
associated with increased cumulative ore production is offset by 1)
closure and sealing of older mines. and 2) lower emission rates from new
mines with relatively small cumulative production. Using the first
assumption. EPA calculated total annual emissions of 235.000 City for
underground uranium mines in 1978; i.e.. radon-222 emissions of 150.000
City were determined for those mines that accounted for 64 percent of the
total U30e production. Therefore. total emissions from underground
uranium mines can be estimated by scaling the measured emissions by the
percentage of total production represented by the measured emissions. On
an annual U30e production basis. 235.000 City is equivalent to 25.3
Ci/ton U30a. With the second assumption. EPA used 25.3 Ci/ton U30a as a
factor relating annual short tons of U30a to annual radon-222 emissions.
Provided the average mine's cumulative ore production remains constant,
future radon-222 emissions can be estimated by multiplying 25.3 Ci/ton
U30a times the predicted annual production of U30a (in tons) for the year
desired.
Table 3-4 presents estimated radon-222 emissions for the years 1978.
1982, 1985, and 1990. The U30a produced by underground uranium mines in
1978 and 1982 was obtained from the Department of Energy (DOE83). The
U30a production estimates for 1985 and 1990 were taken from projections
presented in Section 2.3.
Table 3-4.
Predicted radon-222 emissions from underground uranium
mine vents
Year
Estimated U30a production
(short tons)
Predicted emissions
(Ci/y)
1978
1982
1983
1985
1990
9,300
6,300
4,100
3,100
2,300
235,000
159,000
104.000
78,400
58,000
3-11

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The estimated future emissions of radon-222 from underground uranium
mines (Table 3-4) indicate a decreasing trend in annual radon-222 emis-
sions through 1990; however, EPA's forecasting approach does not account
for nonproduction-related factors that may influence radon-222 emissions.
Therefore, the predicted radon-222 emissions should be used primarily to
illustrate general trends.
3.3
Ambient Air Concentrations
3.3.1
New Mexico Study
In 1977, the New Mexico Environmental Improvement Division (NMEID)
carried out a two-year study to determine 1) the sources of high concen-
trations of airborne radioactivity in uranium-producing areas; 2) back-
ground radioactivity levels, as well as levels associated with uranium
mines and milling facilities; and 3) the possibility that New Mexico
standards were being exceeded (Bu83). In the Grants Mineral Belt, more
than 1700 individual outdoor radon-222 air samples were collected and
measured from 33 sites, and radon-222 decay product concentrations inside
buildings and homes at 18 locations were documented. Radon-222 and
radon-222 decay product data were analyzed statistically and compared
with both background and current state and Federal standards. External
radiation exposure rates were also measured at all radon-222 and radon-
222 decay product sampling sites.
The NMEID study revealed that measured radon-222 concentrations in
and near uranium mines exceeded New Mexico Radiation Protection Regula-
tions (NMRPR) for an individual member of the public (3 pCi/liter in
excess of background) at three of nine locations in the Ambrosia Lake
region of the Grants Mineral Belt. Indoor radon-222 decay product mea-
surements showed radiation exposures ranging from near background to
above NMRPR limits. Although radon-222 concentrations measured near
uranium milling facilities not located near uranium mines were not found
to exceed NMRPR limits for an individual, several values were close to or
above the 1 pCi/liter plus background limit for exposure to a population.
The average yearly radon-222 concentration reported by the NMEID for
the Ambrosia Lake region was 4.0 pCi/liter; the highest yearly average
value, measured near a trailer court that was sited close to a mine vent,
was 6.4 pCi/liter. Measured background radon-222 concentrations averaged
approximately 0.5 pCi/liter. The results of the NMEID study are summa-
rized in Tables 3-5 and 3-6 and in Figures 3-3 and 3-4. Statistical
analyses and conclusions are presented in Table 3-7. The NMEID data
appear to indicate that radon-222 emissions from uranium mines have
indeed influenced ambient radon-222 concentrations.
The NMEID stated that it clearly would be inadvisable to locate any
future housing in areas where radionuclide concentrations were determined
to be near or in excess of radiation protection limits. The NMEID scien-
tists also suggested that every effort be made to avoid future siting of
mine vents near populated areas. The NMEID also recognized a need for
documentating radon-222 background levels for definition of "background"
in its radiation protection regulations.
3-12

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Table 3-5.
First-year radon-222 averages by station (Bu83)
(pCi/liter)
  Standard Standard Saaple P(noI'1) . (108'(a)
Station Mean deviaUon arrol' I1U8ber _1) a no..-l)
201 1.12 1.15 0.28 17 <0.01 0.268
202 1. 32 0.99 0.22 20 0.164 0.783
203 1. 92 1.26 0.28 20 <0.01 <0.01
204 2.01 1.35 0.34 16 <0.01 0.456
205 1.55 1.14 0.28 17 <0.01 0.154
206 1.18 1.05 0.24 19 <0.01 0.830
208 1.10 0.97 0.27 13 0.049 0.428
209 0.72 0.69 0.16 18 0.01 0.357
210 1.55 1. 31 0.30 19 0.01 0.074
211 0.44 0.46 0.10 20 0.01 0.822
212 0.36 0.45 0.10 21 0.01 0.064
302 1. 37 0.70 0.16 19 0.354 0.877
305 0.76 0.68 0.16 19 0.034 0.354
307 0.63 0.73 0.18 17 0.01 0.588
309 0.30 0.29 0.07 19 0.180 0.521
310 0.41 0.49 0.12 17 0.01 0.827
313 0.48 0.37 0.08 20 0.017 0.056
315 0.57 0.55 0.12 22 <0.01 0.837
401 1.02 0.25 0.06 20 0.764 0.108
402 3.15 1.66 0.35 22 0.548 0.168
403 3.47 1.87 0.42 20 <0.01 0.540
406 2.96 1.85 0.44 18 0.566 <0.01
407 2.01 1.11 0.26 18 0.043 0.520
408 4.12 3.03 0.66 21 0.188 <0.01
409 3.59 3.32 0.76 19 <0.01 0.388
411 0.91 0.55 0.13 19 0.477 0.081
412 4.23 4.56 1. 27 13 <0.01 0.427
414 1.50 1.17 0.27 19 0.037 0.469
500 0.13 0.08 0.05 3 0.640 0.975
501 0.10 0.03 0.02 3 0.154 0.122
502 0.10 0.05 0.03 3 0.05 0.069
Background (b)  0.57 0.69 0.06 122 <0.01 >0.15
Selected (c) 0.42 0.34 0.07 25 <0.01 0.764
background      
AmbroU, 3.20 2.53 0.24 110 <0.01 0.023
Lake      
Anaco~U(e) 1.06 0.75 0.12 38 <0.07 <0.01
UN-HP 1.83 1.24 0.17 53 <0.01 <0.01
(a) Probability that a normal/log-normal distribution would have a test
statistic larger than that calculated for the data at each station.
If values are less than 0.05. the distribution is not normal/log-
normal uaing the 95% level of aignificance.  
(b) Composed of all 8amples taken at stations 201. 209. 211. 212. 307.
313. 415. 500. 501. 502.    
(c) Twenty-five samples chosen at random from all individual background
8amples.      
(d) Pooled aamples taken at atatione 402. 403. 406. 407. 409. 412.
(a) Pooled ..-pl.. taken at atation. 302. 305.  
(f) Poolad a.-pla. taken at atation. 203. 204. 205.  
   3-13   

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Table 3-6.
Second-year radon-222 averages by station (Bu83)
(pCt/liter)
   It81ldard It81ldard I_pIe P(DOrt) P(L08ta)
StaUon Mean deviaUon arror _ber ad) a Doraal)
201 0.81 0.75 0.17 20 0.011 0.544
203 1. 51 1.11 0.24 22 <0.01 0.409
204 1.89 1.00 0.21 23 0.357 0.826
205 1.12 0.83 0.18 22 <0.01 0.631
206 0.93 0.83 0.19 20 0.015 0.210
208 0.84 0.64 0.14 20 0.016 0.917
209 0.79 0.57 0.12 23 0.072 0.167
210 1.41 1.35 0.31 19 0.015 <0.01
211 0.71 0.81 0.17 23 <0.01 0.249
212 0.61 0.59 0.14 18 0.042 0.266
302 0.78 0.50 0.11 21 0.404 0.097
305 0.95 0.76 0.17 21 <0.01 0.976
307 0.55 0.53 0.12 21 <0.01 0.024
309 0.21 0.13 0.03 21 0.386 <0.01
310 0.36 0.28 0.06 20 0.156 0.061
313 0.47 0.51 0.11 23 <0.01 0.536
315 0.49 0.37 0.1>8 24 0.030 0.048
401 1.18 0.43 0.10 19 0.303 0.12
402 6.40 3.28 0.66 25 <0.01 0.914
403 5.70 2.23 0.50 20 0.213 0.096
406 3.40 2.00 0.44 21 0.096 <0.01
407 3.23 1.55 0.32 23 0.773 0.035
408 5.77 3.59 0.77 22 0.470 0.246
409 5.43 3.58 0.75 23 0.360 <0.01
411 1.10 0.78 0.16 24 0.193 0.051
412 3.74 2.53 0.52 24 0.330 <0.01
414 1.69 1.23 0.26 22 0.050 0.436
415 0.14 0.22 0.05 19 <0.01 0.482
500 0.15 0.12 0.03 16 0.806 0.675
501 0.17 0.13 0.03 15 0.087 0.681
502 0.47 1.04 0.33 10 <0.01 0.456
b 0.51 0.62 0.05 188 <0.01 >0.15
Background
Selected 0.53 0.73 0.15 25 <0.01 0.546
background (c) 
AmbrotU 4.66 2.89 0.25 136 0.091 <0.01
Lake        
Anaco~~,(e) 0.87 0.64 0.10 42 <0.01 0.407
UN-HP 1.51 1.02 0.12 67 <0.01 >0.15
(a) Probability that a Dormal/log-normal distribution would have a test
statistic larger than that calculated for the data at each station.
If values are less than 0.05, the distribution is not normal/log-
normal using the 95% level of significance.  
(b) Composed of all samples taken at stations 201, 209, 211, 212, 307,
313, 415, 500, 501, 502.     
(c) Twenty-five samples chosen at random from all individual background
samples.        
(d) Pooled samples taken at .tations 402, 403, 406, 407, 409, 412.
(a) Pooled ..-pla. taken at 8t8tiona 302, 305.  
(f) Pool ad sampla. taken at .tation. 203, 204, 205.  
    3-14   

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. Radon-222
.. Background Radon
~Uranium Mines
DUranium Faci1ities
S Uranium Tai 1 ings
~ Near Surface Uranium
Minera1 ization
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Scale
Figure 3-3.
First-year radon-222 averages by station
(pCi/liter) .
(Bu83)
3-15

-------
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. a ...
"TN.:. .,~:
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-.
. Radon -222
... Background Radon
~Uranium Mines
CJ Uranium Facil ities
~ Uranium Tail ings
~ Near Surface Uranium
Mineral izat ion
,
.,.,
~
o
I
Mi les
5
-1
Scale
Figure 3-4.
Second-year radon-222 averages by
(pCi/liter) .
station
(Bu83)
3-16

-------
Table 3-7.
concentrations
The t-test(a) probability values comparing radon-222
at mine mill stations with background(b) and regulatory
limits (Bu83)
   Year One    Year Two 
  +3 pCi/ +1 pCi/  +3 pCi/ +1 pCi/ 
Station liter liter +0 liter liter +0
202 <0.01 0.337 () <0.01 <0.01 <0.01 0.060
203 <0.01 0.047 c <0.01 <0.01 0.473 <0.01
204 <0.01 0.052 <0.01 <0.01 0.083 <0.01
205 <0.01 0.326 <0.01 <0.01 0.042 <0.01
206 <0.01 0.183 <0.01 <0.01 <0.01 0.051
208 <0.01 O. 138 0.014 <0.01 <0.01 0.072
210 <0.01 0.337 <0.01 <0.01 0.363 <0.01
302 <0.01 0.396 <0.01 <0.01 <0.01 0.087
305 <0.01 <0.01 0.029 <0.01 <0.01 0.034
315 <0.01 <0.01 0.123 <0.01 <0.01 0.409
401 <0.01 
-------
NMEID has conducted additional research pertaining to the impact of
emissions from underground uranium mines on ambient radon-222 concentra-
tions. However. a summary of the results. which will be published as
Appendix C (Bu83). was not available to EPA.
3.3.2
Kerr-McGee Data
In 1983. Kerr-McGee Corporation compared monitored radon-222 and
radon-222 decay product concentrations around uranium mines in the
Ambrosia Lake area of New Mexico during periods of normal uranium mining
operations and during partial shutdown periods (Sh83). During partial
shutdown periods. either the Kerr-McGee mines or the Homestake mines were
shut down; however. mines of both companies were not shut down simultane-
ously. The average radon-222 concentrations measured by Kerr-McGee near
two underground uranium mines in the Ambrosia Lake area are shown in
Tables 3-8 and 3-9. These data are presented as representative of the
Kerr-McGee data. Other data are available in the Radian report.
In a statistical analysis of the data. Radian Corporation (a consul-
tant to Kerr-McGee) found no conclusive evidence that mining operations
increased the radon-222 or radon-222 decay product levels in the area
(Sh83). Radian concluded the following: "...the short-term variability
in radon-222 and radon-222 decay product levels is probably greater than
the contributions of the mines...at least for the study period. Given
the large temporal variability. it is difficult to quantify the contribu-
tion of the mining operations accurately" (Sh83).
In a 1983 communication to EPA. Kerr-McGee states: "...radon re-
leased from mining and milling activities has no statistically discern-
ible impact on natural environmental radon levels...radon concentrations'
during operations are not statistically different from radon concentra-
tions during suspended operations. i.e.. when only background sources of
radon are present." Kerr-McGee concluded that local micrometeorology.
rather than mining operations. is the dominant influence on ambient
radon-222 and radon-222 progeny levels (Sh83).
3.3.3
Additional Study Needed
The NMEID data suggest that uranium mining operations have a sub-
stantial effect on nearby ambient radon-222 concentrations. while Kerr-
McGee's data and statistical analysis argue against such a hypothesis.
Additional study is needed regarding the relationship between emissions
from underground uranium mines and ambient radon-222 concentrations near
the mines.
3-18

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Table 3-8.
Radon-222 concentration (pCi/1iter) for mine 1:
least 20 oata points (Sh83)
days with at
   During During 
  Before Kerr-McGee Homes take  After
  Shutdown Shutdown Shutdown Shutdown
  (May 15- (June 14- (June 28- (July 12-
  June 13) June 27) July 11) August 2)-
Mean  4.07 2.95 3.73 6.60a
Median  4.55 2.75 3.57 4.98
Number of observations 9 9 10 18
Standard Deviation 1.13 1.06 0.923 4.19
90% Confidence (3.37, (2.29, (3.19, (4.88,
Interval for Mean 4.77) 3.61) 4.27) 8.32)
(a)
The six daily average values at the end of the after-period ranged from 8.07
to 17.2. The twelve values preceding these values ranged from 2.74 to 5.78.
The six-day high period had a much larger effect on the mean than on the
median.
Table 3-9.
Radon-222 concentration (pCi/1iter) for mine 2:
least 20 data points (Sh83)
days with at
   During During 
  Before Kerr-McGee Homes take  After
  Shutdown Shutdown Shutdown Shutdown
  (May 15- (June 14- (June 28- (July 12-
  June 13) June 27) July 11) August 2)
Mean  5.15 4.39 4.68 6.63
Median  5.42 3.70 4.79 7.50
Number of observations 6 7 5 4
Standard Deviation 0.585 1. 71 1.19 1.82
90% Confidence (4.67, (3.13, (3.55, (4.49,
Interval for Mean 5.63) 5.65) 5.81) 8.77)
3-19

-------
B184
Bo74
Br84
Bu83
DOE83
EPA84
Ja79
Ja80
NRC81
REFERENCES
Bloomster C. H. and Bruno G. A., Cumulative Ore Production and
Radon Release Information for Underground Uranium Mines,
Pacific Northwest Laboratory, Richland, Washington, May 1984.
Bossard F. C. et al., Survey of Radon Daughter Emission Sourc-
es, Rates and Current Control Practices, a report prepared for
the U.S. Bureau of Mines under Contract G0133138, June 30,
1974.
Bruno G. A. et a1., U.S. Uranium Mining Industry: Background
Information on Economics and Emissions, PNL5035, Pacific North-
west Laboratory, Rich1and, Washington, March 1984.
Buhl T., Millard J., Baggett D., Brough T., and Trevathan S.,
Radon and Radon Progeny Concentrations in New Mexico's Uranium
Mining and Milling District, New Mexico Health and Environment
Department, 1983.
Department of Energy, Statistical Data of the Uranium Industry,
GJO-100(83), Grand Junction, Colorado, January 1983.
Environmental Protection Agency, Radionuc1ides:
Information Document for Final Rules, Volume II,
022-2, Office of Radiation Programs, Washington,
1984.
Background
EPA-520/1-84-
D.C., October
Jackson P.O., et a1., Radon-222 Emissions in Ventilation Air
Exhausted from Underground Uranium Mines--Interim Report,
PNL2888, Pacific Northwest Laboratory, Richland, Washington,
March 1979.
Jackson P.O., et al. An Investigation of Radon-222 Emissions
from Underground Uranium Mines--Progress Report 2, PNL3262,
Pacific Northwest Laboratory, Rich1and, Washington, February
1980.
Nuclear Regulatory Commission, Radon Releases from Uranium
Mining and Milling and Their Calculated Health Effects, NUREG-
0757, Office of Nuclear Material Safety and Safeguards, NRC,
Washington, D.C., February 1981.
3-20

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Sh83
Th74
Shelly W. J. and Still E. T. (Kerr-McGee Corporation), Written
communication to R. J. Guimond of EPA containing following
report: Williamson H. J., Statistical Analysis of Radon and
Radon Daughter Concentrations in the Ambrosia Lake Area, New
Mexico, Radian Corporation, 1983.
Thompkins R., Slipping the Pill to Radon Daughters, Canadian
_Mining Journal, September 1974.
3-21

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Chapter 4: ESTIMATING THE RISK DUE TO EXPOSURE
FROM RADON-222 DECAY PRODUCTS
4.1
Introduction
This chapter describes the methodology the EPA uses to estimate the
exposure and the health detriment, i.e., lung cancer, due to radon-222 in
the general environment. First, radon-222 exposure pathways are
explained and the EPA risk model is described; then, estimates of risks
due to radon-222 progeny (radon-222 decay products) made by various
scientific groups are compared, and the range of risk coefficients to be
used in the risk assessment are selected. Earlier studies have shown
that all risk estimates have a degree of uncertainty (EPA84).
The occurrence of radiation-induced cancer is very infrequent when
compared with the current incidence of all cancers. Even among heavily
irradiated populations (e.g., some of the uranium mine workers in epidemi-
ologic studies), the precision and accuracy of the number of lung cancers
resulting from radiation is uncertain because of the small sampling
segment and because of the large variability in the data. Also, the
small sampling of exposed populations have not been followed for their
full lifetime; therefore, information on the ultimate effects of their
exposure is limited. .
When considered in light of experiments with animals and various
theories of carcinogenesis and mutagenesis, the observational data on
cancers related to human exposure to radiation are subject to a number of
interpretations. This, in turn, leads to differing estimates of radiation
risks by both individual radiation scientists and expert advisory groups.
Readers should bear in mind that estimating radiation risks is not a
mature science and that the evaluation of the risk due to radon-222 decay
products (progeny) will change as additional information becomes available.
Nevertheless, a substantial data base is available for use in developing
risk estimates, and these estimates can be useful in the development of
regulatory requirements.
4.2
Radon-222 Exposure Pathways
4.2.1
Physical Considerations
Radon-222 from underground mining operations enters the general
environment from mine ventilation exhaust systems and through waste
4-1

-------
materials from mining operations. The half-life of radon-222 is 3.8
days; therefore, some atoms of gaseous radon-222 can travel thousands of
miles through the atmosphere before they decay. As shown in Figure 4-1,
the radon decay process involves seven principal decay products before
the radon becomes nonradioactive lead. The first four short half-life
radioactive decay products of radon are the most important sources of
cancer risk. These generally occur within less than an hour. Members of
the decay chain with relatively long half-lives (beginning with lead-210,
which has a 22-year half-life) are more likely to be ingested than inhaled
and, in general, present much smaller risks.
The principal short half-life products of radon-222 are polonium-218,
lead-214, bismuth-214, and polonium-214. Polonium-218, the first decay
product, has a half-life of just over 3 minutes. This is long enough for
most of the electrically charged polonium atoms to attach themselves to
microscopic airborne dust particles that are typically less than a mil-
lionth of a meter in diameter. When inhaled, these small particles have
a good chance of sticking to the moist epithelial lining of the bronchi.
Most inhaled particles are eventually cleared from the bronchi by
mucus, but not quickly enough to keep the bronchial epithelium from being
exposed to alpha particles from the decay of polonium-218 and polonium-214.
This highly ionizing radiation passes through and delivers radiation
doses to several types of lung cells. Adequate characterization of the
exact doses delivered to cells that eventually become cancerous cannot be
made. Also, knowledge of the deposition pattern of the radioactive
particles in the lung is based on theoretical models, and the distances
from the radioactive particles to cells that are susceptible are assumed,
not known. Further, there is some disagreement about the types of bronchial
cells where cancer originates. Therefore, EPA estimates of lung cancer
risk are based on the amount of inhaled radon-222 decay products to which
people are exposed, rather than on the dose absorbed by the lung.
Ingrowth of Radon-222 Decay Products
At the point where radon-222 diffuses out of the interior mine
surfaces, the concentration of associated radon-222 decay products is
zero because those decay products generated prior to diffusion from the
surface have been captured in earth. As soon as radon-222 is airborne,
ingrowth of decay products commences and a secular equilibrium between
the amount of radon-222 and the amount of each decay product is approached.
At secular equilibrium, the activity of radon-222 and all its short
half-life decay products is equal and alpha activity per unit of radon-222
concentration is at its maximum value. As a means of accounting for
incomplete equilibrium before this state is achieved, the "equilibrium
fraction" is defined as the ratio of the potential alpha energy from
those decay products actually present to the potential alpha energy that
would be present at complete equilibrium of the decay products with the
radon-222. In mine vent exhausts, an equilibrium fraction of 0.2 has
been measured (Dr80). As radon-222 and its decay products are transported
by the wind, the equilibrium fraction increases with distance from the
mine vent, and at great distances, approaches the theoretical maximum
4-2

-------
a
3.05
222         
86Rn         
 - a,l'        
 3.82 days        
 II         
218         
84 Po         
min.          
  8,"'(  8,"'(      
214 26.R 214 19.~ 214     
82 Pb . ~... 83 Bi min. 84Po     
mln.     
     a,y  10-4 s  
     1 . 64 x  
     II     
      8."'(  8 
     210 22.3 210 5.91 210
     82 Pb --" 83Bi  84Po
     yrs. days
          a."'(
          138.1
          days
          206
          82Pb
          STABLE
Figure 4-1.
Radon-222 decay series.
4-3

-------
value of one; however, depletion processes, such as dry deposition and
precipitation scavenging, selectively remove decay products (but not
radon), so complete equilibrium of the decay products with the radon-222
is seldom, if ever, reached.
When radon-222 and its decay products enter a structure, the building
ventilation rate is the principal factor affecting the equilibrium fraction
indoors. The equilibrium fraction can also be affected by other considera-
tions, however, such as the indoor surface-to-volume ratio and the dust
loading in indoor air (P078).
In estimating the exposures of nearby individuals to radon-222 decay
products in Chapter 5, the model uses the calculated effective equilibrium
fraction at selected distances from a mine exhaust (see Table 4-4 presented
later in this section). For estimating population exposures, a
population-distance weighted effective equilibrium fraction would be
appropriate, but it is impractical to calculate this fraction. Indoor
exposure is the dominant form of exposure due to radon-222 [Americans
spend about 75 percent of their time indoors (M076, Oa72)]; therefore,
this effective equilibrium fraction does not depend greatly on the
distance from the mine vent. In this assessment, an effective
equilibrium fraction of 70 percent is assumed for calculating the
exposure of populations because most of the affected individuals are at
some distance from the mine exhausts (see Section 4.4.1).
4.2.2
Characterizing Exposures to the General Population vis-a-vis
Underground Miners
Although considerable progress has been made in modeling the deposi-
tion of particulate material in the lung (Ha82, Ja80, Ja81), adequate
characterization of the bronchial dose delivered by alpha particles from
inhaled radon-222 progeny attached to dust particles is not yet possible.
Knowledge is still lacking concerning the kinds of cells in which bronchial
cancer is initiated (Mc78) and the depth of these cells in the bronchial
epithelium. Current estimates of the exposure dose of inhaled radon-222
progeny actually causing radiogenic cancer are based on average doses,
which mayor may not be relevant (E185). Until more reliable estimates
of the bronchial dose become available, following the precedents set in
the 1972 and 1980 NAS reports (NAS72, NAS80) (i.e., estimating the risk
. due to radon-222 progeny on the basis of exposure rather than dose ~
se) appears to be a prudent approach. This is called the epidemiological
approach; i.e., risk is estimated on the basis of observed cancers follow-
ing occupational exposure to radon-222 progeny.
Exposures to radon-222 decay products under working conditions are
commonly reported in a special unit called the working level (WL). One
working level is any concentration of short half-life radon-222 progeny
having 1.3 x 105 MeV per liter of potential alpha energy (FRC67). [A WL
is also equivalent to approximately 100 pCi/liter of radon-222 in secular
equilibrium with its short-lived decay products.] This unit was developed
because the concentration of specific radon-222 progeny depends on ventila-
tion rates and other factors. A working level month (WLM) is the unit
4-4

-------
used to characterize a mine worker's exposure to one working level of
radon-222 progeny for a working month of 170 hours. Inasmuch as the
results of epidemiological studies are expressed in units of WL and WLM,
a method for determining how they can be interpreted for members of the
general population exposed to radon progeny is explained.
For a given concentration of radon-222 progeny, the amount of poten-
tial alpha energy a member of the general population inhales in a month
is more than the amount a mine worker receives in a working month.
Although members of the general population are exposed longer (up to 24
hours per day, 7 days a week), the average amount of air inhaled per
minute (minute volume) is less in this group than that for a mine worker
when periods of sleeping and resting are taken into account (EPA79). For
comparison of the radon-222 progeny exposure of a mine worker with that
of a member of the general population, one should compare the amount of
potential alpha energy each inhales per year (Ev69).
The EPA assumes that a mine worker inhales 30 liters per minute
(averaged over a work day). This average corresponds to about 4 hours of
light activity and 4 hours of moderately heavy work per day (ICRP75).
The new ICRP radon model, however, assumes an inhalation rate of 20
liters per minute for mine workers, which corresponds to 8 hours of light
activity per day (ICRP81). Whereas this may be appropriate for nuclear
workers, studies of the metabolic rate of mine workers clearly show that
they are not engaged in light activity only (Sp56, ICRP75, NASA73).
Therefore, 30 liters appears to be a more realistic estimate of the
average volume per minute for this group. Based on this per-minute
volume, a mine worker inhales 3.6 x 103 cubic meters in a working year of
2000 hours (ICRP79). One working level of radon-222 progeny is 2.08 x
10-5 joules per cubic meter; therefore, in a working year, the potential
alpha energy inhaled by a mine worker exposed to one working level is 7.5
x 10-2 joules.
According to the ICRP Task Group report on reference man (ICRP75),
an inhaled air volume of 2.3 x 104 liters per day is assumed for adult
males in the general population and 2.1 x 104 liters per day for adult
females, or an average of 2.2 x 104 liters per day for members of the
adult population. This average volume results in 1.67 x 10-1 joules per
year of inhaled potential alpha energy from an exposure to one working
level of radon-222 progeny for 365.25 days. Although it may be technically
inappropriate to quantify the amount of potential alpha particle energy
inhaled by a member of the general population in working level months,
this amounts to an annual exposure equivalent to 27 WLM (26.7) to an
adult member of the general population exposed 24 hours a day. For
indoor exposure, an occupancy factor of 0.75 (see above) is assumed;
thus, an indoor exposure to one WL results in an annual exposure equiva-
lent to 20 WLM (EPA79) in terms of the amount of potential alpha energy
actually inhaled.
The smaller bronchial area of children as opposed to adults more
than offsets their lower per-minute volume; therefore, for a given concen-
tration of radon-222 progeny, the dose to their bronchi, is greater.
4-5

-------
This problem has been addressed in a paper by Hofmann and Steinhausler
(Ho77), in which they indicate that exposures received during childhood
are about 50 percent greater than- adult exposures. This information was
used to prepare Table 4-1, which lists the age-dependent potential alpha
energy exposure used in the risk assessments described in the next sub-
section.* The results in Table 4-1 have been rounded to two significant
figures. The larger exposure to children relative to that to adults
increases the estimated mortality due to lifetime exposure from birth by
about 20 percent.
Table 4-1. Potential alpha energy inhaled during one year of exposure
to one working level (2.08 x 10-5 jout~, per cubic meter)
as a function of age
Age of
general population
(years)
Joules
WLM (a)
0-2
3-5
6-11
12-15
16-19
20-22
23 or more
Lifetime Average
0.22
0.27
0.30
0.27
0.24
0.20
0.17
0.195
35
43
49
43
38
32
27
31.4
(a) Assuming a WLM corresponds to about 6.2 x 10-g joules of potential
alpha particle energy inhaled (see text).
The exposure model just described has also been examined in terms of
the average dose delivered to bronchial tissue by using the most detailed
dose model available--the five-lobe lung model developed by Harley and
Pasternack (Ha82). The breathing patterns assumed for each group are a
bronchial dose of 0.64 rad per WLM for mine workers and 0.51 rad for an
adult member of the general population (Ha83). It appears that the
factors not included in our simple model (e.g., the fraction of unattached
radon-222 progeny) are not very important compared with other sources of
uncertainty in the risk estimates.
*
The assumptions on per-minute volume, etc., for mine workers and the
general population just described are the same as those used in the
preparation of the EPA report entitled "Indoor Radiation Exposure
Due to Radium-226 in Florida Phosphate Lands" (EPA79) and Final
Environmental Impact Statements (EPA82, 83a).
4-6

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4.3
Health Risk From Exposure to Radon-222 Decay Products
4.3.1
Risk Models
A wealth of data indicates that exposure to the bronchial epithelium
of underground mine workers causes an increase in bronchial lung cancer,
both among smokers and nonsmokers. Several estimates of the risk due to
radon-22~progeny have been published since the EPA model was developed.
Two recent reviews on experience among underground mine workers are of
particular interest. The 1980 NAS BEIR-3 Report (NAS80) contains a
review of epidemiological studies on mine workers. A lengthy report
entitled "Risk Estimates for the Health Effects of Alpha Radiation,"
which was prepared by D. C. Thomas and K. C. McNeil for the Atomic Energy
Control Board (AECB) of Canada, reanalyzes many of these epidemiological
studies in a consistent fashion so that the modeling assumptions are the
same for all of the data sets (Th82).
The manner in which radiogenic lung cancers are distributed in time,
after a minimum induction period, is a crucial factor in numerical risk
estimates. For radiation-induced leukemia and bone cancer, the period of
risk expression is relatively brief; most occur within 25 years of expo-
sure. For other radiation-induced cancers (including lung cancer),
however, it appears that people are at risk for the remainder of their
lives (NAS80). None of the epidemiological studies of underground mine
workers provides information on lifetime expression; indeed, most of the
study populations are still alive and still at risk. Lifetime risks
cannot be estimated only on the basis of observations to date; therefore,
a model is needed to project the risk beyond the period of direct obser-
vation. As discussed in the 1980 NAS BEIR report, there are two basic
models of risk projection: (1) the absolute risk projection model, in
which it is assumed that the annual numerical excess cancer per unit
exposure (or dose) continues throughout life; and (2) the relative risk
projection model, in which it is assumed that the observed percentage
increase of the baseline cancer risk per unit exposure (or dose) is
constant with time (NAS80).
In the case of lung cancer and most other solid cancers, a relative
risk model leads to larger estimated risks because of the high prevalence
of such cancers at old age. Figure 4-2 shows the number of lung cancer
deaths that occurred in the U.S. population as a function of age in 1970.
The decrease in the number of deaths for ages greater than 65 years is
due to depletion of the population by competing risks, not a decrease in
the age-specific incidence of lung cancer mortality, which is relatively
constant until age 95 (NCHS73). The age-specific mortality of under-
ground mine workers dying of radiogenic lung cancer shows the same pat-
tern of death as a function of age as the general male population (Ra84,
E185). In a recent review (E185), it was shown that a relative risk
model can adequately account for the temporal pattern of cancer deaths
observed in underground mine workers, whereas absolute risk projection
models fail to do so.
4-7

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Figure 4-2.
105
U.S. lung cancer mortality by age--1970.
4-8

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4.3.2
The EPA Relative Risk Model
Since 1978, the Agency has based risk estimates due to inhaled
radon-222 progeny on a linear dose response function, a relative risk
projection model, and a minimum induction period of 10 years. Lifetime
risks are projected on the assumption that exposure to 1 WLM increases
the age-specific risk of lung cancer by 3 percent over the age-specific
rate in the U.S. population as a whole. The life table analysis described
in Bu81 and EPA84 is used to project this risk over a full lifespan.
The EPA model has been described in detail (EPA79, E179). A review
of this model in light of the more recent information described herein
revealed that the major assumptions, linear response, and relative risk
projection have been affirmed. The A-bomb survivor data clearly indicate
that the absolute risk of radiogenic lung cancer has continued to increase
among these survivors, whereas their relative risk has remained reasonably
constant (Ka82). The UNSCEAR, the ICRP, and the 1980 NAS Committee have
continued to use a linear dose response to estimate the risk of lung
cancer due to inhaled radon-222 progeny. Thomas and McNeill's analysis
(Th82) indicates that the use of linearity is not unduly conservative and
may, in fact, underestimate the risk at low doses. The 1980 NAS BEIR
Committee reached a similar conclusion (NAS80).
A major limitation of earlier EPA risk estimates is the uncertainty
in the relative risk coefficient used (3 percent increase per WLM). This
value is based on the excess mortality due to lung cancer among exposed
mine workers of various ages, many of whom smoked. Therefore, it repre-
sents an average value for a mixed population of smokers, former smokers,
and nonsmokers. This assumption may lead to an exaggerated risk estimate
(as discussed below) because smoking was more prevalent among some of the
groups of mine workers studied than it is among the U.S. general population
today.
In a recent paper, Radford and Renard (Ra84) reported on the results
of a long-term study of Swedish iron miners who were exposed to radon-222
progeny. This study is unique in that most of the miners were exposed to
less than 100 WLM and the risks to smokers and nonsmokers were considered
separately. The absolute risks of the two groups were similar, 20 fatali-
ties per 106 person-year WLM for smokers compared with 16 fatalities for
nonsmokers. The total number of lung cancer fatalities for nonsmokers is
small; therefore, the estimate of 16 fatalities is not too reliable.
Whereas absolute risks were comparable for the smoking and nonsmoking
miners, relative risks were not. The baseline incidence of lung cancer
mortality is much lower among nonsmokers than among smokers. This resulted
in a relative risk for nonsmoking exposed miners relative to unexposed
nonsmokers that was about four times larger than the relative risk for
exposed smokers. This larger relative risk does not, however, fully
compensate for the lower baseline incidence of nonsmokers. Therefore,
this study of Swedish iron miners indicates that a relative risk coeffi-
cient of 3 percent per WLM may be too high when applied to the population
as a whole. Further followup of this and other groups of mine workers
may provide more reliable data on the risk to nonsmokers, and EPA expects
4-9

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to incorporate separate consideration of smokers and nonsmokers into its
analyses as more data become available.
Although occupational exposures to pollutants other than radon-222
progeny are probably not important factors in the observed lung cancer
risk for underground mine workers (E179, Th82, Mu83, Ra84), the use of
occupational risk data to estimate the risk of a general population is
far from optimal, as it provides no information on the effect of radon-222
progeny exposures to children and women. Although the model continues to
assume that the risk per unit exposure during childhood is no more effec-
tive than that occurring to adults, this assumption may not be correct.
The A-bomb survivor data indicate that, in general, the risk from child-
hood exposure to low linear energy transfer (LET) radiation is greater
and continues throughout life (Ka82). As yet, specific data for lung
cancer have not been collected (Ka82). Another limitation of the data
for underground mine workers is the absence of women in the studied
populations. The A-bomb survivor data indicate that women are as sensi-
tive as men to radiogenic lung cancer, even though they tend to smoke
less as a group (Pr83). These data are not conclusive, however.
4.3.3
Other Risk Estimates
National Academy of Sciences BEIR-3
The National Academy of Sciences BEIR-3 Committee formulated an
age-dependent absolute risk model with increasing risk for older age
groups (NAS80). Estimates of the risk per WLM for various ages and the
estimated minimum induction period for lung cancer following exposure
(NAS80, pp. 325 and 327 respectively), which are summarized in Table 4-2,
have been used to calculate the lifetime risk of lung cancer mortality
from lifetime exposure to persons in the general population. This was
done by means of the same life table analysis that was used to calculate
other EPA risk estimates (Bu81).
Table 4-2. Age-dependent risk coefficients and minimum induction
period for lung cancer due to inhaling radon-222 progeny
(NAS80)
Age at
diagnosis
(years)
Excess lung cancers
(cases per 106
person-year WLM)
Minimum
induction period
(years)
0-15
16-36
36-50
51-64
65 or
more
o
o
10
20
50
25
25-15
10
10
10
4-10

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The zero risk shown in Table 4-2 for those under 35 years of age at
exposure does not mean that no harm occurs; rather, it means that the
risk is not expressed until the person is more than 35 years old, i.e.,
only after the minimum induction period. The sequence of increasing risk
with age shown in this table is not unlike the increase in lung cancer
with age observed in unexposed populations; therefore, the pattern of
excess risk over time is similar to that found by using a relative risk
projectton model.
Atomic Energy Control Board of Canada
Recently, Thomas and McNeil conducted a thorough analytical investi-
gation of the incidence of lung cancer among uranium mine workers for the
Atomic Energy Control Board (AECB) of Canada (Th82). These investigators
tested a number of risk models on all of the epidemiological studies that
contained enough data to define a dose-response function. They concluded
that lung cancer per WLM among males increased 2.3 percent and that a
relative risk projection model was more consistent with the incidence of
excess lung cancer observed in groups of underground mine workers than
any of the other models they tested. This is the only analysis that
treated each data set in consistent fashion and utilized to the extent
possible such modern epidemiological techniques as controlling for age at
exposure and duration of fo11owup. The AECB estimate for lifetime exposure
to Canadian males is 830 fatalities per million person WLM (Th82). In
Table 4-3, this estimate has been adjusted to 600 fatalities per million
person WLM (which would be the appropriate estimate for the U.S. 1970
general population) by determining the "best estimate" risk (see p. 114
in Th82). The best estimate was then multiplied by the ratio of lung
cancers due to radon-222 in the U.S. 1970 general population to lung
cancers in the U.S. 1970 male population as calculated in the EPA model.
The 1978 reference life tables for Canadian males and U.S. males are
quite similar; therefore, the simple proportional relationship of general
population deaths to male deaths should give a reasonable estimate.
International Commission on Radiological Protection
The International Commission on Radiological Protection (ICRP) has
made risk estimates for occupational exposure for working adults
(ICRP81). The ICRP estimates (shown in Table 4-3) are based on their
epidemiological approach; i.e., the exposure to mine workers in WLM and
the risk per WLM observed in epidemiological studies of underground mine
workers. The ICRP epidemiological approach assumes an average expression
period of 30 years for lung cancer. Children, who have a much longer
average expression period, are excluded from this estimate. The ICRP has
not explicitly projected the risk to mine workers beyond the years of
observation, even though most of the mine workers on whom these estimates
are based are still alive and continuing to die of lung cancer.
4-11

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Table 4-3.
Risk estimate for exposures to radon-222 progeny(a)
 Fatalities per Exposure Expression 
Organization 106 person WLM period period Reference
EPA (b) 760 Lifetime Lifetime EPA84
NAS ~EtR-3 (b) 730 Lifetime Lifetime NAS80
AECB c 600 Lifetime Lifetime Th82
ICRP 150-450 Working 30 years ICRP81
  lifetime  
UNSCl(~ 200-450 Lifetime 40 years UN 77 
NCRP 130 Lifetime Lifetime NCRP 84
(a) The number of fatalities per million-person WLM listed for EPA and
NAS BEIR-3 differs from those previously published by EPA [860 fatali-
ties per 106 PWLM and 850 fatalities per 106 PWLM, respectively
(EPA83a)] because the increased potential alpha energy exposure
during childhood is now included in the denominator of this ratio.
The risk estimates for various sources of radon-222 in the environment
have not changed, because all were calculated via a life table analysis
yielding deaths per 100,000 exposed rather than deaths per person
WLM.

(b) Assumes increased exposure during childhood, Table 4-1.
(c)
Adjusted for the 1970 U.S. general population, see text.

(d) Assumes risk diminishes exponentially with a 20-year halftime.
The ICRP has also made risk estimates based on a dosimetric approach.
These estimates are in the lower part of the range shown for the epidemio-
logical approach in Table 4-3. In their dosimetric approach, the ICRP
assumes that the risk per rad for lung tissue is 0.12 of the risk of
cancer and genetic damage following whole-body exposure (ICRP77). For
exposure to radon-222 progeny, the ICRP divides this factor of 0.12 into
two equal parts. A weighting factor of 0.06 is used to assess the risk
from a high dose to bronchial tissue, where radiogenic lung cancer is
observed in exposed underground mine workers. The other half of the lung
cancer weighting factor, another 0.06 of the total body risk, is used to
assess the risk to the pulmonary region, which receives a comparatively
small dose from radon-222 progeny and where human lung cancer is seldom,
if ever, found.
UNSCEAR
The United Nations Scientific Committee on the Effects of Atomic
Radiation (UNSCEAR) estimate is for a general population and assumes an
expression time of 40 years (UNSCEAR77). Like the ICRP, UNSCEAR did not
4-12

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make use of an explicit projection of risk of fatal lung cancer over a
full lifetime (Table 4-3).
National Council on Radiation Protection and Measurements
The National Council on Radiation Protection and Measurements (NCRP)
risk estimate, the last entry in Table 4-3, is based on an analysis by
Harley and Pasternack (Ha82). It is of particular interest because, like
the EPA and AECB estimates, it is based on a life table analysis of the
lifetime risk due to lifetime exposure (NCRP84). This estimate utilizes
an absolute risk projection model with a relatively low risk coefficient,
10 cases per 106 person WLM per year at risk, which is the smallest of
those listed by the NAS BEIR-3 Committee (cf. Table 4-2). Moreover, they
have assumed that the risk of lung cancer following irradiation decreases
exponentially with a 20-year half-life and, therefore, exposures occurring
early in life present very little risk. The NCRP assumption of a 20-year
half-life for radiation injury reduces the estimated lifetime risk by
about a factor of 2.5. Without this assumption, the NCRP risk estimate
would be the same as the midpoint of the UNSCEAR estimate (325 fatalities
per million person WLM). The assumed decrease in risk as used by NCRP is
questionable. If lung cancer risk decreased over time with a 20-year
half-life, the excess lung cancer observed in Japanese A-bomb survivors
would have decreased during the period this group has been followed
(1950-1982); whereas, to the contrary, their absolute lung cancer risk
has markedly increased (Ka82).
4.3.4
Comparison of Risk Estimates
The EPA, NAS BEIR-3, AECB, UNSCEAR, ICRP, and NCRP estimates of the
risk of lung cancer due to inhaled radon-222 progeny are listed in Table
4-3. That the EPA, NAS (BEIR-3), and the AECB estimates are in agreement
is not unexpected as each of these estimates is based on lifetime exposure
and lifetime expression of the incurred risk. Conversely, the three
lower risk estimates shown in Table 4-3, either do not explicitly include
these conditions or they include other modifying factors. Nevertheless,
Table 4-3 indicates a divergence, by a factor of about 6, in risk estimates
for exposure to radon-222 progeny. Thus, the use of a single risk coeffi-
cient may not be appropriate because it could result in some believing
that the risk is well known when obviously it is not. The EPA, BEIR-3,
and AECB estimates may be slightly high because they represent relative
risks based on adult males, many of whom smoked. The actual risk may be
smaller for a population that includes adult females, children, and
nonsmokers. The UNSCEAR and ICRP estimates are probably low because they
represent absolute risk estimates that do not completely take into ac-
count the duration of the exposure and/or the duration of the risk during
a lifetime. The NCRP estimate is likely to be very low, as a low risk
coefficient was used in an absolute risk model and it was assumed that
the risk decreases exponentially after the exposure.
To estimate the range of reasonable risks from exposure to radon-222
progeny for this document, EPA has averaged the estimates of BEIR-3, the
EPA model, and the AECB to establish an upper bound of the range. The
4-13

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lower bound of the range was established by averaging the UNSCEAR and
ICRP estimates. The Agency chose not to include the NCRP estimate in its
determination of the lower bound because this estimate is believed to be
outside the lower bound. Therefore, the EPA has chosen risk coefficients
of 300 to 700 fatalities per million person WLM as reasonable estimates
for the possible range of effects from inhaling radon-222 progeny for a
full lifetime. Although these two risk estimates do not encompass the
full range of uncertainty, they seem to illustrate the breadth of much of
current scientific opinion.
If a 1.2 percent relative risk coefficient were used in the EPA
model for calculation of the lifetime risk of lifetime exposure, the
estimated lung cancer mortality would be 300/106 person WLM. If a 2.8
percent relative risk coefficient were used, estimated lung cancer mortal-
ity would be 700/106 person WLM. In this document, risk estimates are
presented for both these values (see Section 4.4.2).
4.4
Estimating the Risks
4.4.1
Exposure
The exposure to radon-222 progeny at a site of interest is based on
the calculated radon-222 concentration and the calculated radon-222
progeny equilibrium fraction:
Radon progeny
concentration
=
Radon
concentration
x
Radon progeny
equilibrium factor

(f eff)
e
x
9.84 X 10-3
(WL)
(pCi/liter)
(WL per pCi/liter)
For individual risk estimation, emission data and meteorological data for
the source and the EPA Industrial Source Complex Model (Bo79) are used to
compute air concentrations of radon-222 at selected distances from a
source or a group of such sources. For regional populations, emission
data and meteorological data are used with the AIRDOS-EPA model (Mo79) to
calculate air concentrations of radon-222; for national populations,
emission data and meteorological data are used with the NOAA Trajectory
Dispersion Model (NRC79). (Some examples of the calculations are presented
in Chapter 5.)
Calculations of radon-222 progeny equilibrium fractions are based on
distance from a source and the time required to reach the exposure site.
By using the ingrowth model of Evans (Ev69) and the potential alpha
energy data of UNSCEAR (UNSCEAR77), the outdoor equilibrium fraction can
be calculated by the expression:

f out = 1.0 - 0.047ge-t/4.39 -2.1963e-t/38.6 + 1.2442e-t/28.4
e
where t is the travel time in minutes.
4-14

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Radon-222 and radon-222 progeny are in partial equilibrium at the
mine exhaust vent (Dr80); therefore, an initial time correction must be
made to ensure that correct equilibrium fractions are estimated outside
of the mine.
An initial time
observed equilibrium
Then at a_distance x
given by:
(t ) of 11.79 min, which is consistent with the
o
fraction of 0.2 in the mine vent (EPA80), is assumed.
(m), for a 3.5 mls windspeed, the time t (min) is
t = t
o
+ x
3.5 x 60
where the factor of 60 converts the travel time from seconds to minutes.
The indoor equilibrium fraction presumes that those decay products
associated with the radon-222 release also enter the building and that a
ventilation rate of 1 h-l (one air change per hour) in combination with
indoor removal processes (e.g., deposition onto room surfaces) produces
an indoor equilibrium fraction of 0.35 when there are no decay products
in ventilation air and 0.70 when the decay products are in equilibrium
with the radon-222 in the ventilating air (EPA83b). A simple linear
interpolation is used:

f in = 0.35 (1 + f out).
e e
If one further assumes that a person spends 75 percent of his or her
time indoors and the remaining 25 percent outdoors at the same location,
the effective equilibrium fraction is given by:

f eff = 0.75 f in + 0.25 f out
e e e
An example of the case for a 3.5 mls windspeed and various distances
from the source is given in Table 4-4.
Removal processes outdoors were assumed to limit the equilibrium
fraction to 0.85, which corresponds to an indoor equilibrium fraction of
0.65 and an effective fraction of 0.70. Table 4-4 shows that this limit
is reached at a distance of 17,000 meters.
4.4.2
Risk Estimation
After the exposure has been calculated, the risk can be estimated
for an individual or a population.
Individual
Individual risks are calculated by using the life table methodology
described by Bunger et a1. (Bu81). Relative risk projections for lifetime
exposure based on coefficients of 1.2 percent and 2.8 percent for the
radiation-induced increase in lung cancer yield rounded-off estimates of
4-15

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300 deaths/lOG person WLM and 700 deaths/lOG person WLM respectively.
The risk coefficients of 1.2 percent and 2.8 percent were used in develop-
ing the risk assessments discussed in Section 4.3.4.
Table 4-4.
Radon-222 decay product equilibriu~a;raction at selected
distances from a mine vent
Distance (m)
f out
e
f in
e
f eff
e
o 0.200 0.420 0.365
100 0.207 0.422 0.369
150 0.210 0.424 0.370
200 0.213 0.425 0.372
250 0.216 0.426 0.373
300 0.219 0.427 0.375
400 0.226 0.429 0.378
500 0.232 0.431 0.381
600 0.238 0.433 0.384
800 0.251 0.438 0.391
1,000 0.263 0.444 0.397
1,500 0.293 0.453 0.413
2,000 0.323 0.463 0.428
2,500 0.351 0.473 0.442
3,000 0.379 0.483 0.457
4,000 0.432 0.501 0.484
5,000 0.482 0.519 0.510
6,000 0.528 0.535 0.533
8,000 0.612 0.564 0.576
10,000 0.682 0.589 0.612
15,000 0.812 0.634 0.679
>17,000 0.850 0.650 0.700
(a) Calculations presume an initial equilibrium fraction of 0.2 and a 3.5
m/s windspeed for the outdoor equilibrium fraction; an indoor equili-
brium fraction of 0.35 for no radon-222 decay products in the ventila-
tion air and 0.70 for ventilation air with 100 percent equilibrium
between radon-222 and its decay products; and, for the effective
equilibrium, 75 percent of time indoors and 25 percent of time outdoors.
Using these risk coefficients in the CAIRD Code (Co78), one can
calculate the risk from any exposure to radon-222 progeny across any time
period. Usually, the lifetime risk from lifetime exposure at a constant
level is calculated. The age-specific differences in intake listed in
Table 4-1 are included in calculations of the lifetime risk. Results of
representative calculations of lifetime risk are given in Table 4-5.
4-16

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Table 4-5.
Lifetime risk for lifetime exposure to a given
level of radon-222 progeny
Radon-222 progeny
concentration (WL)
Lifetime risk of lung cancer
700 deaths/106 person WLM 300 deaths/106 person WLM
0.0001
0.001
0.01
0.1
0.2
1.58 x 10-4
1.58 x 10-3
1.56 X 10-2
1.42 x 10-1
2.55 x 10-1
6.78 x 10-5
6.78 x 10-4
6.75 x 10-3
6.46 X 10-2
1.23 x 10-1
The lifetime risk estimates shown in Table 4-5 are for lifetime
exposure'at a constant level of radon-222 progeny. These factors were
used with WL exg~fures that were calculated by using radon-222 concentra-
tions and an f determined as detailed in Table 4-4 to estimate the
e
risks listed in Table 5-5.
Regional
Collective (population) risks for the region are calculated from the
annual collective exposure (person WLM) for the population in the assess-
ment area by a computerized methodology known as AIRDOS-EPA (Mo79). an
effective equilibrium fraction of 0.7 is presumed because little
collective exposure takes place near the mine.
Formally, the annual coective exposure, SE' can be defined as:
~
SE = JoEn(E)dE
where SE is the collective exposure (person WLM), E is the exposure level
(WL~I), and neE) is the population density at exposure level E (person/WLM).
Practically, however, the collective exposure is calculated by
dividing the assessment area into cells and then calculating the population,
Ni (persons), and the annual exposure, Ei (WLM), for each one. The
collective exposure is then calculated by the following expression:

E
SE = i EiNi
where the summation is carried out over all the cells. Customarily, the
regional population exposure is limited to persons within 80 km of the
mine.
The population risk is calculated by using the same risk factors as
for the individual risk calculations (700 deaths per 106 person WLM or
300 deaths per 106 person WLM).
4-17

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National
Radon-222 released from mine vents can be transported beyond the
80-km regional cutoff. A trajectory dispersion model developed by NOAA
(NRC79) has been used to estimate the national impact of radon-222 releases
from mine vents. This model calculates the average radon-222 exposure to
the U.S. population from unit releases at four typical uranium mining and
milling sites. The model yields radon-222 concentrations (in picocuries
per liter) in air, which are then converted to decay product exposures by
assuming an effective equilibrium fraction of 0.7. National annual
collective exposures (person WLM) are calculated for distances beyond the
80-km regional limit. Risks to the national population are calculated
for an exposed population of 200 million persons.
4-18

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Bo79
Bu81
Co78
Dr80
E179
E185
EPA79
EPA80
REFERENCES
Bowers J. F., Bjorklund J. R., and Cheney C. S., Industrial
Source Complex (ISC) Dispersion Model, Users Guide, Volume I,
EPA-450/4-79-030, Source Receptor Analysis Branch, USEPA,
Research Triangle Park, North Carolina, December 1979.
Bunger B., Cook J. R., and Barrick M. K., Life Table Method-
ology for Evaluating Radiation Risk: An Application Based on
Occupational Exposure, Health Physics 40, 439-455, 1981.
Cook J. R., Bunger B. M., and Barrick M. K., A Computer Code
for Cohort Analyzing Increased Risk of Death (CAIRD, Technical
Report 520/4-78-12, Office of Radiation Programs, USEPA, Wash-
ington, D.C., 1978.
Droppo J. G., Jackson P.O., Nickola P. W., Perkins R. W.,
Sehmel G. A., Thomas C. W., Thomas V. W., and Wogman N. A., An
Environmental Study of Active and Inactive Uranium Mines and
Their Effluents, Part I, EPA Contract Report 80-2, PNL-3069,
Pt. I, UC-ll, Pacific Northwest Laboratory, Richland, Washing-
ton, August 1980.
Ellett W. H. and Nelson N. S., Environmental Hazards From Radon
Daughter Radiation, pp. 114-148, in: Conference/Workshop on
Lung Cancer Epidemiology and Industrial Applications of Sputum
Cytology, Colorado School of Mines Press, Golden, Colorado,
1979.
Ellett W. H. and Nelson N. S., Epidemiology and Risk Assess-
ment: Tests of Models for Lung Cancer Induction, in: Proceed-
ings of the 7th Life Sciences Symposium, Indoor Air and Human
Health, Oak Ridge, 1984, to be published 1985.
Environmental Protection Agency, Indoor Radiation Exposure Due
to Radium-226 in Florida Phosphate Lands, EPA 520-4-78-013,
Office of Radiation Programs, USEPA, Washington, D. C., revised
printing, July 1979.
Environmental Protection Agency, An Environmental Study of
Active and Inactive Uranium Mines and Their Effluents, Part I,
EPA Contract Report 80-2, USEPA, Washington, D.C., 1980.
4-19

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EPA82
EPA83a
EPA83b
EPA84
Ev69
FRC67
Ha82
Ha83
Ho77
ICRP75
ICRP77
Environmental Protection Agency, Final Environmental Impact
Statement for Remedial Action Standards for Inactive Uranium
Processing Sites (40 CFR 192), Volume I, EPA 520/4-82-013-1,
Office of Radiation Programs, USEPA, Washington, D.C., 1982.
Environmental Protection Agency, Final Environmental Impact
Statement for Standards for the Control of Byproduct Materials
from Uranium Ore Processing (40 CFR 192), Volume I, EPA 520/1-
83-008-1, Office of Radiation Programs, USEPA, Washington,
D.C., 1983.
Environmental Protection Agency, Final Environmental Impact
Statement for Standards for the Control of Byproduct Materials
from Uranium Ore Processing (40 CFR 192), Volume II, p. A.2-33,
EPA 520/1-83-008-2, Office of Radiation Programs, USEPA, Wash-
ington, D.C., 1983.
Environmental Protection Agency, Radionuclides Background
Information Document for Final Rules, Volume I, EPA 520/1-84-
022-1, Office of Radiation Programs, USEPA, Washington, D.C.
1984.
Evans R., Engineers Guide to the Elementary Behavior of Radon
Daughters, Health Physics, 17, 229-252, 1969.
Federal Radiation Council, Radiation Guidance for Federal
Agencies, Memorandum for the President, July 21, 1967, Fed.
Reg., ~, 11183-84, August 1, 1967.
Harley N. H. and Pasternack B. S., Environmental Radon Daughter
Alpha Dose Factors in a Five-Lobed Human Lung, Health Physics,
42, 789-799, 1982.
Harley N. H., personal communication to Dr. N. Nelson, Office
of Radiation Programs, U.S. Environmental Protection Agency,
Washington, D.C., 1983.
Hofmann W. and Steinhausler F., Dose Calculations for Infants
and Youths due to the Inhalation of Radon~nd Its Decay Products
in the Normal Environment, in: Proceedings of the 4th Interna-
tional Congress of the International Radiation Protection
Association, Paris, 1, 497-500, 1977.
International Commission on Radiological Protection, Report of
the Task Group on Reference Man, ICRP Publ. 23, Pergamon Press,
New York, 1975.
International Commission on Radiological Protection,
Recommendations of the International Commission on Radiological
Protection, ICRP Publ. 26, Ann. ICRP. 1 (1), Pergamon Press,
1977 .
4-20

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ICRP79
ICRP81
Ja80
Ja81
Ka82
Mc78
Mo76
Mo79
Mu83
NAS72
International Commission on Radiological Protection, Limits for
Intakes of Radionuclides by Workers, ICRP Publication 30, Part
1, Ann. ICRP, 1 (3/4), Pergamon Press, New York, 1979.
International Commission on Radiological Protection, Limits for
Intakes of Radionuclides by Workers, ICRP Publication 32, Part
3, Ann. ICRP, ~ (2/3), Pergamon Press, 1981.
Jacobi W. and Eisfeld K., Dose to Tissue and Effective Dose
Equivalent by Inhalation of Radon-222 and Radon-220 and Their
Short-Lived Daughters, GFS Report S-626, Gesellschaft fuer
Strahlen and Unweltforschung mbH, Munich, 1980.
James A. C., Jacobi W. and Steinhausler F., Respiratory Tract
Dosimetry of Radon and Thoron Daughters: The State-of-the-Art
and Implications for Epidemiology and Radiology, in: Proceedings
of the International Conference on Hazards in Mining: Control,
Measurement, and Medical Aspects, October 4-9, 1981, Golden,
Colorado, 42-54, edited by Manual Gomez, Society of Mining
Engineers, New York, 1981.
Kato H. and Schull W. J., Studies of the Mortality of A-bomb
Survivors, 7. Mortality, 1950-1978: Part I, Cancer Mortality,
Rad. Research, 90, 395-432, 1982. (Also published by the
Radiation Effec~Research Foundation as: RERF TR 12-80, Life
Span Study Report 9. Part 1.)
McDowell E. M., McLaughlin J. S., Merenyi D. K., Kieffer R. F.,
Harris C. C., and Trump B. F., The Respiratory Epithelium V.
Histogenesis of Lung Carcinomas in Humans, J. Natl. Cancer
Inst., ~, 587-606, 1978.
Moeller D. W. and Underhill D. W., Final Report on Study of the
Effects of Building Materials on Population Dose Equivalent,
School of Public Health, Harvard University, Boston, Massachu-
setts, December 1976.
Moore R. E., Baes C. F. III, McDowell-Boyer L. M., Watson A.
P., Hoffman F. 0., Pleasant J. C., and Miller C. W., AIRDOS-
EPA: A Computerized Methodology for Estimating Environmental
Concentrations and Doses to Man from Airborne Releases of
Radionuclides, ORNL-5532, Oak Ridge National Laboratory, Oak
Ridge, Tennessee, 1979.
Muller J., Wheeler W. C., Gentleman J. F., Suranyi G., and
Kusiak R. A., Study of Mortality of Ontario Miners, 1955-1977,
Part I, Ontario Ministry of Labor, Ontario, Canada, May 1983.
National Academy of Sciences - National Research Council, The
Effects of Populations of Exposures to Low Levels of Ionizing
Radiation, Report of the Committee on the Biological Effects of
Ionizing Radiations (BEIR Report), NAS, Washington, D.C., 1972.
4-21

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NAS80
NASA73
NCHS73
NCRP84
NRC79
Oa72
Po78
Pr83
Ra84
Sp56
Th82
UNSCEAR77
National Academy of Sciences - National Research Council, The
Effects of Populations of Exposures to Low Levels of Ionizing
Radiation: 1980, Committee on the Biological Effects of Ioniz-
ing Radiation (BEIR-3 Report), NAS, Washington, D.C., 1980.
National Aeronautics and Space Administration, Bioastronautics
Data Book, NASA SP-3006, 2nd Edition, edited by J. R. Parker
and V. R. West, NASA, Washington, D.C., 1973.
National Center for Health Statistics, Public Use Tape, Vital
Statistics - Mortality, Cause of Death Summary - 1970, PB80-
133333, NTIS, Washington, D.C., 1973.
National Council on Radiation Protection and Measurements,
Evaluation of Occupational and Environmental Exposures to Radon
and Recommendations, NCRP Report No. 78, NCRPM, Washington,
D. C., 1984.
Nuclear Regulatory Commission, Draft Generic Environmental
Impact Statement on Uranium Milling, Volume II, NUREG-0511,
USNRC, Washington, D.C., 1979.
Oakley D. T., Natural Radiation Exposure in the United States,
ORP/SID 72-1, USEPA, Washington, D.C., 1972.
Porstendorfer J., Wicke A., and Schraub A., The Influence of
Exhalation, Ventilation, and Deposition Processes Upon the
Concentration of Radon, Thoron and Their Decay Products in Room
Air, Health Physics, 34, 465-473, 1978.
Prentice R. L., Yoshimoto Y., and Mason M. W., Relationship of
Cigarette Smoking and Radiation Exposure to Cancer Mortality in
Hiroshima and Nagasaki, J. Nat. Cancer Inst., 70, 611-622,
1983.
Radford E. P. and Renard K. G. St. Cl., Lung Cancer in Swedish
Iron Miners Exposed to Low Doses of Radon Daughters, N. Engl.
J. Med., 310, 1485-1494, 1984.
Spector W. S., editor, Handbook of Biological Data, Table 314,
Energy Cost, Work: Man, W. B. Sanders Co., Philadelphia, 1956.
Thomas D. C. and McNeill K. G., Risk Estimates for the Health
Effects of Alpha Radiation, Report INFO-0081, Atomic Energy
Control Board, Ottawa, Canada, 1982.
United Nations Scientific Committee on the Effects of
Radiation, Sources and Effects of Ionizing Radiation,
the General Assembly, with Annexes, UN publication E.
United Nations, New York, 1977.
Atomic
Report to
77 IX.l.,
4-22

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Chapter 5:
RISK ASSESSMENT
5.1
Introduction
This chapter presents an assessment of the risks of fatal cancer due
to radon-222 emissions from underground uranium mines. Two measures of
risk are presented: risk to nearby individuals and risks to the total
population. The first measure refers to the estimated increased lifetime
risk imposed upon individuals who spend their entire lifetime at a loca-
tion near a mine, where the predicted radon-222 concentrations are high-
est. Nearby individual risks are expressed as a probability, i.e., 0.001
(1/1000). This means that the increased chance of cancer in a person
exposed for a lifetime is 1 in 1,000. Estimates of nearby individual
risks must be interpreted cautiously, however, because few people gen-
erally reside at the location of highest risk or spend their whole lives
at such locations. The second measure, total population risk, considers
people exposed to all radon-222 concentrations, low as well as high.
Expressed in terms of annual number of fatal cancer cases, it provides a
measure of the overall publi~ health impact. The risk estimates pre-
sented in this chapter were calculated by using the models and procedures
described in Chapter 4.
The following approach was used in this chapter. First, an assess-
ment was made of the risk to nearby individuals and the total population
from emissions from a reference (i.e., model) mine on a reference (i.e.,
model) site. The total population risk from emissions from all under-
ground uranium mines at selected time intervals was then assessed by
using the emission rate estimates from Chapter 3. Finally, the actual
nearby individual risks from specific "case study" mines were calculated
for comparison with the reference mine risks.
5.2
Reference Underground Uranium Mine
5.2.1
Description
Radon-222 emissions from
of these mines) are presented
production from large uranium
underground uranium (according to the age
in Table 5-1. The estimated 1982 ore
mines is presented in Table 5-2.
The parameters of the reference (model) mine used in assessing the
risks from radon-222 emissions are presented in Table 5-3. The reference
mine emissions and ore production rate in this table were developed from
5-1

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Table 5-1. Summary of radon-222 emissions
from underground uranium mines according to age (Ja80)(a)
   New mines(b)   Old mines(c)
  Age Radon-222 emissions Age  Radon-222 emissions
Mine (years) (Ci/y) (years)  (Ci/y)
A  3 7,400    
B  9 4,500    
C  9 4,600    
D  7 3,600    
E      21   29,800
F      20   9,400
G  4 1,800    
H      21   15,200
J      20   7,900
K      19   6,400
L      29   1,400
R      20   14,800
U  4  900    
V  2 1,000    
Y  6 17,500    
Z      17   2,600
Average 6 5,200 21   10,900
(a) Data from measurements made in 1978 and 1979.  
(b) Mines that have been in operation less than 10 years. 
(c) Mines that have been in operation more than 10 years. 
5-2

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Table 5-2.
Estimated 1982 ore production of large underground uranium
mines (Br84)
Mine
Estimated 1982 production
(109 tons/y)
New mines «10 years)
King Solomon
Velvet
Tony M
Hack Canyon
Pidgeon
Kanab North
La Sal
Hecla
Big Eagle
Golden Eagle(a)
Mt. Taylor
Old Church Rock
Church Rock-East
Kerr-McGe~A)Section 19
Nose Rock
Mariano Lake
38.0
51. 6
137.6
63.1
(a)
(a)
81.7
14.8
16.6
328.5
28.6
72.3
127.2
36.8
Average
62
Old mines (~10 years)
Sunday
Dermo-Snyder
Wilson-Silverbell
Lisbon
Sheep Mountain
Church Rock-NE
Church Rock-l
Kerr-McGee
Section 30-East
Section 30-West
Section 35
Section 36
Homestake
Section 23
Section 25
Schwartzwalder
41.7
58.5
16.5
73.3
o
171.9
176.8
119.5
132. 4
195.1
111.2
208.9
67.9
198.8
Average
112
(a) Not operational
5-3

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data in Tables 5-1 and 5-2. The reference mine is a large mine that has
been in operation for about 20 years. The radon-222 emission rate from
this reference mine is 11,000 Ci/y, the average value for older mines (in
1978-1979) as shown in Table 5-1. The mine has five vents arranged in
the configuration shown in Figure 5-1.
Table 5-3.
Reference underground uranium mine parameters
Parameter
Value
Ore grade
0.22 percent U30S
Ore production
112,000 tons/y
Mine age
~20 years
Days of operation
250 days/y
Number of vents
5
Vent height
3 meters
11,000 Ci/y(a)
Radon-222 emissions
(a)2,200 Ci/y from each vent.
Both horizontal and vertical vent configurations were used in assess-
ing the radon-222 emissions from the reference mine. Horizontal vents
were treated as ground-level releases (i.e.. no plume rise). Vertical
vents were modeled for plume rise by using the following parameters:
exit velocity = 16.2 meters/sec. vent diameter = 1.5 meters, and exit
temperature = 287°K. These represent average values from six mines for
which actual vent data were available (DR84).
5.2.2
Health Risk Assessment of the Reference Underground Uranium Mine
The lifetime risk to nearby individuals and the number of fatal
cancers per year of operation due to radon-222 emissions from the refer-
ence underground uranium mine are presented in this section.
Risk to Nearby Individuals
The radon-222 concentrations in air near an underground mine are
highly dependent upon a number of factors. The primary factors are
emission rates and dispersion characteristics of the atmosphere, i.e.,
meteorological parameters. Other factors include the spatial distribu-
tion and orientation of the exhaust vents (vertical or horizontal) and
the momentum flux of the exhaust air (velocity times flow rate). Plume
rise due to the momentum flux can significantly affect the ground-level
5-4

-------
4
VENT
3
VENT
1
SHAFT
Figure 5-1.
o
'00 200 300 400
METERS
~ VEZNT
Reference underground mine.
5-5
500

-------
radon-222 concentrations near the mine vents. Little buoyancy-induced
plume rise is expected because the vent air streams are at or near am-
bient air temperatures. Discharges through horizontal vents will have
little or no plume rise, whereas discharges through vertical vents will
usually have a significant amount of plume rise. The extent to which
plume rise actually affects the ground-level radon-222 concentrations
near specific underground uranium mines is somewhat uncertain because of
limited information on vent configurations and momentum fluxes.
In addition, the relatively low height of the vent releases makes it
uncertain that the computed plume rise will be realized in all cases.
Near-release influences, such as buildings, walls, hills, and vegetation,
can easily change local flow characteristics so that downwash of the
plume may occur. Even when no downwash occurs, such objects increase
local dispersion and tend to decrease the plume rise.
The technique selected for estimating ambient air concentrations of
radon-222 near the mine was the use of an air quality dispersion model.
The Industrial Source Complex Model (B079) in its long-term mode (ISCLT)
was selected as an appropriate model for underground uranium mine vents.
The ISCLT model has the ability to model many spatially differentiated
emission sources for many receptors and for an annual average concentra-
tion that is consistent with risk assessment requirements. The ISCLT
model uses climatological data frequency summaries with Gaussian disper-
sion calculations to estimate radon-222 concentrations at any receptor
location (out to about 80 km) for spatially varying vents. The model
internally calculates plume rise due to momentum flux and uses the calcu-
lated plume height as the effective release height of the vertical vent.
For the best simulation of the horizontal vents, the vents were treated
as small area sources with no plume rise. Meteorological data from the
Ambrosia Lake District of New Mexico are used in the ISCLT model to
estimate the radon-222 concentration. Appendix B includes a summary of
the meteorological data used.
The range of potential radon-222 concentrations that would exist
near an underground uranium mine was shown by calculating the estimated
ground-level concentration from the reference mine emissions for both
ground-level releases (all horizontal vents, i.e., no plume rise) and
elevated releases (all vertical vents with plume rise). A ground-level
release with no plume rise represents a worst-case assumption in terms of
the computed ground-level radon-222 concentrations. A release with plume
rise represents a lower-bound case for computed radon-222 concentrations.
The radon-222 concentrations computed on the basis of these two assump-
tions will cover the range of concentrations that can result from various
local influences on plume rise. The spatial distribution patterns of
ground-level radon-222 concentrations estimated using the ISCLT model are
shown in Figures 5-2 and 5-3 for the cases of no plume rise and plume
rise, respectively. As these figures show, modeled concentrations for
the reference mine are up to five times higher when all horizontal vents
(no plume rise) are assumed than when all vertical vents (with plume
rise) are assumed. The shape of the isopleths of concentration is a
function of the frequency distribution of meteorological parameters.
5-6

-------
~~
'm . i
Figure 5-2. Modeled incremental radon-222 concentrations around the reference
underground uranium mine, assuming no plume/rise, pCi/liter (Dr84).
5-7

-------
~i
0.1
Figure 5-3. Modeled incremental radon-222 concentrations around the reference
underground uranium mine, assuming a plume/rise, pCi/ li ter (Dr8,4).
5-8

-------
Table 5-4 shows the estimated radon-222 concentrations at various
distances from the main shaft of the reference mine for releases with and
without plume rise. The maximum concentration is the highest value that
occurred at that distance at any of the 16 wind directions (i.e., sec-
tors). Also shown is the average value of all sectors at each distance.
In all cases, the maximum is about a factor of two higher than the ave-
rage. The most likely radon-222 concentrations at these locations will
fall somewhere within the range of values shown. Appendix B (Tables B-1
and B-2) includes a copy of the computer printout of the ISCLT model
results. Appendix B (Table B-5) also shows the number and distribution
of people living near large underground uranium mines in 1982. These
data, obtained through a PNL field survey (Br84). showed that about 600
people lived within 2 kilometers of large underground mines in 1982.
Many of the mines operating in 1982 have since been shut down; therefore,
fewer people are now likely to be living in the areas surveyed in 1982.
Table 5-4. Estimates of radon-222 concentrations in air at
selected distances from the underground uranium mine
(pCi/liter)
 Computed with no plume Computed with plume
Distance rise (horizontal vents) rise (vertical vents)
from mine       
shaft to Maximum Average Maximum Average
receptor concentration concentration concentration concentration
(m) in a sector for all sectors in a sector for all sectors
500 12   5.6 0.35 0.20
1,000 4.5   2.0 0.36 0.19
2,000 0.96   0.48 0.22 0.13
3,000 0.48   0.26 0.15 0.10
5,000 0.22   0.13 0.12 0.06
7,000 0.13   0.09 0.08 0.04
10,000 0.09   0.04 0.06 0.03
The estimated concentration from horizontal vent releases shown in
Table 5-4 at 500 meters from the mine shaft is a worst-case situation, as
the receptor is sited between a series of mine vents and relatively close
(within a few hundred meters) to one of the vents where all of the vents
involved are horizontal (i.e., no plume rise). It is unlikely that such
an extremely high concentration now actually exists near an underground
uranium mine or that any persons are located at such a site.
Table 5-5 shows the estimated radon-222 decay product exposures and
lifetime risks of fatal cancer to nearby individuals from radon-222
emissions from the reference mine. At a distance of 1000 meters from the
5-9

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Table 5-5. Estimates of annual radon-222 decay product exposures
and lifetime risks of fatal cancer at selected distances from
the reference underground uranium mine
   Horizontal vents (no plume rise) Vertical vents (with plume rise
   Rado~-   Lifetime   Annual Lifetime
 Distance (a)  eff (b) 222 c) Annual risks to Rad~n)  expo- risks to
 (pCil exposure nearby d 222 c  sure nearby d
 (m) f liter) (WLM) individuals () (pCi/liter)  (WLM) individuals ( )
 e 
 500(e) 0.38 12. 1.4 7.0E-2 (3.0E-2) 0.35 4. 1 E- 2 2.0E-3 (8.7E-4)
 1 ,000 0.40 4.5 5.5E-l 2.7E-2 (1. 2E-2) 0.36 4.4E-2 2.2E-3 (9.4E-4)
 2,000 0.43 0.96 1. 3E-l 6.4E-3 (2. 8E-3) 0.22 2.9E-2 1. 4E-3 (6.2E-4)
VI            
I 3,000 0.46 0.48 6.8E-2 3.4E-3 (1.5E-3) 0.15 2. 1 E- 2 1.0E-3 (4.5E-4)
~
o           
 5,000 0.51 0.22 3.5E-2 1. 7 E- 3 (7. 4E-4) 0.12 1. 9E-2 9.4E-4 (4.0E-4)
 7,000 0.56 0.13 2.2E-2 1.lE-3 (4.7E-4) 0.08 1. 4E-2 6.8E-4 (2.9E-4)
 10,000 0.61 0.09 1. 7E-2 8.4E-4 (3.6E-4) 0.06 1.lE-2 5.6E-4 (2.4E-4)
(a) Distance from mine shaft.

(b) Effective equilibrium fraction from Table 4-4.

(c)Radon-222 concentrations from Table 5-4.

(d)The values in the first column are based on a risk factor of 700 deaths/l06
in parentheses are based on a risk factor of 300 deaths/l06 person WLM (see
(e)
This location is very close to one of the mine vents.
person WLM and the values
Chapter 4).

-------
mine shaft, the estimated lief time risk ranged from about 1 in 1000 to
about 3 in 100.
Population Risks
The radon-222 decay product exposures and the number of fatal can-
cers per year of operation for the reference underground uranium mine are
presented in Table 5-6. Estimates are presented for the regional popula-
tion (i.e., population within 80 km of the mine) and the national popula-
tion (i.e., population beyond 80 km). The number of fatal cancers per
year of reference mine operation are estimated to vary from 0.02 to 0.05
in the regional population and 0.05 to 0.12 in the national population.
Table 5-6. Annual radon-222 decay product exposures and number of
fatal cancers to the population due to radon-222 emissions
from the reference underground uranium mine
Regional population
National population
 Person- Fatal cancers/y Person- Fatal cancers/y
Source ~M of operation(a) ~M of operation(a)
Underground      
uranium mine 68 4.8E-2 (2.0E-2) 170 1.2E-1 (5.1E-2)
(a) The values in the first column are based on a risk factor of 700
deaths/106 person ~ and the values in parentheses are based on a
risk factor of 300 deaths/106 person ~ (see Chapter 4).
The regional population risks shown are for a reference site in the
Ambrosia Lake District of New Mexico with a regional population of
36,000. Table 5-7 lists the characteristics of the reference site. The
national population risks were estimated by using exposure data from a
trajectory dispersion model developed by NOAA (Tr79). This model calcu-
lates a collective radon-222 exposure of 7 x 104 person-pCi/m3 to the
population of the United States from a 1 kCi radon-222 release from
Grants, New Mexico; it does not include exposures to the regional popula-
tion. Based on an equilibrium fraction of 0.7, the collective radon-222
decay product exposure to the U.S. population is estimated to be 15
person-~M per kCi of radon-222 released from Grants, New Mexico.
5-11

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Table 5-7.
Characteristics of Ambrosia Lake Site
Characteristic
Location
Latitude: 35°21'8"
Longitude: 107°50'17"
Grants/Gnt-Milan (WBAN=93057)
A-F
54/01-54/12
20 cm
13.2°C
800 m
Meteorological data
Stability categories
Period of record
Annual rainfall
Average temperature
Average mixing height
Population
0-8 km
0-80 km
o persons
3.60E+4
5.3
Total Health Risk From Radon-222 Emissions From All Underground
Uranium Mines
Estimates of the total health risk from radon-222 emissions from all
underground uranium mines for the years 1978, 1982, 1983, 1985, and 1990
are shown in Table 5-8. These estimates were based on emission estimates
previously presented in Table 3-4 and used the following risk factors,
which were developed from the reference mine data:
Regional population risk/kCi of radon-222:
0.0044 to 0.0018 fatal cancers/kCi
National population risk/kCi of radon-222:
0.011 to 0.0046 fatal cancers/kCi.
Table 5-8. Estimates of total health risk from radon-222 emissions
from all underground uranium mines for 1978, 1982, 1983, 1985, and 1990
 Number of fatal cancers/year by population segment(a)
Year  Regional National Total
1978 1.0 (0.42) 2.6 (1.1) 3.6 (1. 5)
1982 0.70 (0.29) 1.7 (0.73) 2.4 (1.0)
1983 0.46 (0.19) 1.1 (0.48) 1.6 (0.67)
1985 0.34 (0.14) 0.86 (0.36) 1.2 (0.50)
1990 0.25 (0.10) 0.64 (0.27) 0.89 (0.37)
(a)The values in the first column are based on a risk factor of 700
deaths/106 person-WLM and the values in parentheses are based on a
risk factor of 300 deaths/106 person-WLM (see Chapter 4).
5-12

-------
mine shaft, the estimated lief time risk ranged from about 1 in 1000 to
about 3 in 100.
Population Risks
The radon-222 decay product exposures and the number of fatal can-
cers per year of operation for the reference underground uranium mine are
presented in Table 5-6. Estimates are presented for the regional popula-
tion (i.e., population within 80 km of the mine) and the national popula-
tion (i.e., population beyond 80 km). The number of fatal cancers per
year of reference mine operation are estimated to vary from 0.02 to 0.05
in the regional population and 0.05 to 0.12 in the national population.
Table 5-6. Annual radon-222 decay product exposures and number of
fatal cancers to the population due to radon-222 emissions
from the reference underground uranium mine
Regional population
National population
 Person- Fatal cancers/y Person- Fatal cancers/y
Source ~M of operation(a) ~M of operation(a)
Underground      
uranium mine 68 4.8E-2 (2.0E-2) 170 1.2E-1 (5.1E-2)
(a) The values in the first column are based on a risk factor of 700
deaths/lOG person WLM and the values in parentheses are based on a
risk factor of 300 deaths/lOG person WLM (see Chapter 4).
The regional population risks shown are for a reference site in the
Ambrosia Lake District of New Mexico with a regional population of
36,000. Table 5-7 lists the characteristics of the reference site. The
national population risks were estimated by using exposure data from a
trajectory dispersion model developed by NOAA (Tr79). This model calcu-
lates a collective radon-222 exposure of 7 x 104 person-pCi/m3 to the
population of the United States from a 1 kCi radon-222 release from
Grants, New Mexico; it does not include exposures to the regional popula-
tion. Based on an equilibrium fraction of 0.7, the collective radon-222
decay product exposure to the U.S. population is estimated to be 15
person-WLM per kCi of radon-222 released from Grants, New Mexico.
5-11

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Table 5-7.
Characteristics of Ambrosia Lake Site
Characteristic
Location
Latitude: 35°21
Longitude: 107°
Grants/Gnt-Mi1an
A-F
54/01-54/12
20 cm
13.2°C
800 m
ft 8 in.
50 ft 17 in.
(WBAN=93057)
Meteorological data
Stability categories
Period of record
Annual rainfall
Average temperature
Average mixing height
Population
0-8 km
0-80 km
o persons
3.60E+4
5.3
Total Health Risk From Radon-222 Emissions From All Underground
Uranium Mines
Estimates of the total health risk from radon-222 emissions from all
underground uranium mines for the years 1978, 1982, 1983, 1985, and 1990
are shown in Table 5-8. These estimates were based on emission estimates
previously presented in Table 3-4 and used the following risk factors,
which were developed from the reference mine data:
Regional population risk/kCi of radon-222:
0.0044 to 0.0018 fatal cancers/kCi
National population risk/kCi of radon-222:
0.011 to 0.0046 fatal cancers/kCi.
Table 5-8. Estimates of total health risk from radon-222 emissions
from all underground uranium mines for 1978, 1982, 1983, 1985, and 1990
 Number of fatal cancers/year by population segment(a)
Year  Regional National Total
1978 1.0 (0.42) 2.6 (1.1) 3.6 (1.5)
1982 0.70 (0.29) 1.7 (0.73) 2.4 (1. 0)
1983 0.46 (0.19) 1.1 (0.48) 1.6 (0.67)
1985 0.34 (0.14) 0.86 (0.36) 1.2 (0.50)
1990 0.25 (0.10) 0.64 (0.27) 0.89 (0.37)
(a)The values in the first column are based on a risk factor of 700
deaths/106 per$on-WLM and the values in parentheses are based on a
risk factor of 300 deaths/106 person-WLM (see Chapter 4).
5-12

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5.4
Case Study Mines
5.4.1
Description
As a part of an evaluation of radon-222 concentrations in air near
underground uranium mines, Droppo (Dr84) estimated the radon-222 concen-
trations in air around 14 case study mines. The data for two of these
case-study mines (11 and 12--large mines located in the Ambrosia Lake
District of New Mexico) are presented in this section. These were the
only mines in the study for which actual emission measurement data, vent
release characteristics, vent configurations (horizontal or vertical),
and meteorological data were available. The emission rate data and the
vent release characteristics used were from the 1978-1979 PNL study
(Ja80). The vent configuration information was supplied by the mining
company in 1984. The meteorological data were from the Ambrosia Lake
District of New Mexico.
5.4.2
Health Risk Assessment of Case Study Mines
The radon-222 concentrations in air near case study mines 11 and 12
were estimated with the ISCLT model (Bo79). The input data and the
computed radon-222 concentrations are presented in Appendix B (Tables B-3
and B-4). The estimated annual average radon-222 concentrations in air
at selected distances from case study mines 11 and 12 are presented in
Table 5-9. The estimated radon-222 decay product exposures and individ-
ual lifetime risks to nearby individuals from the radon-222 emissions
from case-study mines 11 and 12 are presented in Table 5-10. The esti-
mated lifetime risk of fatal cancer to a nearby individual at 1000 meters
from the mine shaft was 2 to 4 X 10-3 for mine 11 and 2 to 5 X 10-3 for
mine 12. These values are similar to those estimated for radon-222
emissions from the reference mine. The values for the case-study mines
fall within the range of values estimated for the reference mine.
5-13

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Table 5-9.
Estimates of radon-222 concentrations in air at selected distances
from the case study mines 11 and 12
(pCi/liter)
Case-study mine 11
Case-study mine 12
Distance from mine
shaft to receptor
(m)
Maximum
concentration
in a sector
Average
concentration
for all sectors
Maximum
concentration
in a sector
Average
concentration
for all sectors
\J1
I
......
.j:'-
500(a)  7.2  1.4  5.0 1.6
1,000  0.65  0.36  0.79 0.40
2,000  0.30  0.14  0.24 0.12
3,000  0.12  0.078  0.13 0.065
5,000  0.073  0.043  0.062 0.035
7,000  0.053  0.029  0.039 0.019
10,000  0.037  0.019  0.024 0.011
(a) This location is very close to a mine vent for each of the two mines. 

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Table 5-10. Estimates of annual radon-222 decay product exposures and lifetime risks
of fatal cancer at selected distances for case study mines 11 and 12
    Mine 11    Mine 12  
     Lifetime  Annual Lifetime
 Distance (a)  . Radon- Annual risks to Radon( ) expo- risks to
 eff(b) 222(c) exposure nearby d 222 c sure nearby d
 (m) f  (WLM) individuals() (pCi/liter) (WLM) individuals( )
 e (pCi/liter)
 500(e) 0.38 7.2 8.5E-1 4.2E-2 (1.8E-2) 5.0 5.9E-1 2.9E-2 (1. 2E-2)
 1,000 0.40 0.65 8.0E-2 3.9E-3 (1. 7E-3) 0.79 9.7E-2 4.8E-3 (2.1E-3)
 2,000 0.43 0.30 4.0E-2 2.0E-3 (8. 6E-4) 0.24 3.2E-2 1. 6E-3 (6.7E-4)
 3,000 0.46 0.12 1. 7 E- 2 8.4E-4 (3.6E-4) 0.13 1. 9E-2 9.4E-4 (4.0E-4)
VI          
I 5,000 0.51 0.073 1.2E-2 5.9E-4 (2.5E-4) 0.062 9.8E-3 4.9E-4 (2.1E-4)
t-'
VI         
 7,000 0.56 0.053 9.1E-3 4.5E-4 (1. 9E-4) 0.039 6. 7 E- 3 3.3E-4 (1. 4E-4)
 10,000 0.61 0.037 7.0E-3 3.5E-4 (1. 5E-4) 0.024 4.5E-3 2.2E-4 (9.6E-5)
(a) Distance from mine shaft.

(b) Effective equilibrium fraction from Table 4-4.

(c)Radon-222 concentrations from Table 5-9.

(d)The values in the first column are based on a risk factor of 700 deaths/106 person
values in parentheses are based on a risk factor of 300 deaths/106 person WLM (see

(e) This location is very close to one of the mine vents.
WLM, and the
Chapter 4).

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Bo79
Br84
Dr84
Ja80
Tr79
REFERENCES
Bowers J. F.. Bjorklund J. R.. and Cheney C. S.. Industrial
Source Complex (ISC) Dispersion Model User's Guide Volume I.
EPA-450/4-79-030. U.S. EPA Source Receptor Analysis Branch.
Research Triangle Park. North Carolina. December 1979.
Bruno G. A.. Dirks J. A.. Jackson P.O., and Young J. K.. U.S.
Uranium Mining Industry: Background information on Economics
and Emissions. PNL-5035 (UC-2. 11. 51). Pacific Northwest
Laboratory. Richland. Washington. March 1984.
Droppo J. G.. Modeled Atmospheric Radon Concentrations from
Uranium Mines. draft report, PNL-5239. Pacific Northwest Lab-
oratory. Richland. Washington. September 1984.
Jackson P.O.. Glissmeyer J. A.. Enderlin W. I.. Schwendiman L.
C., Wogman N. A.. and Perkins R. W.. An Investigation of Radon-
222 Emissions From Underground Uranium Mines--Progress Report
2. Pacific Northwest Laboratory. Richland. Washington. February
1980.
Travis C. C.. Watson A. P., McDowell-Boyer L. M.. Cotter S. J.,
Randolph M. L.. and Fields D. E., A Radiological Assessment of
Radon-222 Released From Uranium Mills and Other Natural and
Technologically Enhanced Sources. ORNL/NUREG-55, Oak Ridge
National Laboratory, Oak Ridge, Tennessee. 1979.
5-16

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Chapter 6:
CONTROL TECHNIQUES
6.1
Introduction
Many factors affect the amount of radon-222* emitted to air from an
underground uranium mine; however, a strong relationship exists between
the amount of radon-222 exhausted and the total surface area of the
underground mining activities being ventilated (Ja79 and Ja80) , because
the greatest source of radon-222 emanation is exposed ore and migration
of the gas through surface fissures. The surface area within a mine is a
function of the cumulative amount of ore extracted; therefore, the emis-
sion of radon-222 from underground mines tends to increase with increas-
ing age of the mine.
Little is known about the actual control of atmospheric emissions of
radon-222 because, to date, all control measures have emphasized limiting
the in-mine exposure of mine workers to radon-222. Thus, the practice is
to remove radon-222 from the mine, which ultimately means releasing it to
the atmosphere. Knowing the source of radon-222 and the means by which
it reaches the surface makes it possible to devise and evaluate
conceptual control techniques.
In concept, radon-222 emissions from
duced by one of two basic approaches: 1)
stream to remove radon-222, or 2) prevent
the mine air.
underground mines can be re-
treat the mine ventilation air
the release of radon-222 into
Available treatment methods of the mine ventilation air stream
include various processes of adsorption, absorption, and separation.
These treatment systems have the potential for high control efficiencies
for radon-222, but they are largely unproven and tend to be costly be-
cause of the large volume of air that must be treated. Also, some of the
techniques will produce a waste stream that must be disposed of, and
therefore involve additional expenditures.
Available techniques to prevent the release of radon-222 into mine
air include sealing exposed surfaces with impermeable coatings, backfill-
ing worked-out areas, and bulkheading inactive areas. These techniques
conform more readily to current mining practices and have the potential
*
Radon in this text refers to radon-222 in all cases.
6-1

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of reducing radon-222 emissions and ventilation air requirements in an
operating mine. Although some mines practice some combination of these
methods for employee protection, very little has been done to modify
these practices to include the reduction of emissions to the atmosphere.
Detailed discussions of the two approaches to radon-222 control are
presented in the following subsections.
6.2
Controlling Radon-222 in Mine Ventilation (Exhaust) Air
The cost-effective removal of low levels of radon-222 from large
volumes of air is extremely difficult. Numerous possible methods for
reducing atmospheric emissions of radon-222 in mine ventilation (exhaust)
air have been examined or suggested by various investigative studies.
These approaches include adsorption on activated charcoal, surface ad-
sorption on molecular sieves, cryogenic condensation, separation with
semipermeable membranes, gas centrifuge separation, absorption, chemical
reaction, and several hybrid or combination systems. None of these
systems is currently in use in the industry; nor have any of them been
tried out in a mine.
Each approach is discussed briefly, and pertinent results of prior
studies (with respect to costs and practical application) are summarized.
The cost figures presented herein are believed to be low for several
reasons. Cost values were originally derived by Arthur D. Little in a
1975 study for the Bureau of Mines (Li75) and were based on small-capaci-
ty [2.36-m3/s (5000-scfm)] systems intended for in-mine application and
for operation about 50 percent of the time (2 shifts/day, 260 days/yr).
Actually, radon-222 control of mine ventilation air would require systems
capable of handling air streams of hundreds of thousands of cubic feet
per minute and operating continuously. From an economic and/or technical
standpoint, the methods do not offer promise as a practical means of con-
trolling radon-222 emissions in the large-volume air streams encountered
in mine ventilation exhausts.
6.2.1
Adsorption
Adsorption is a molecular surface phenomenon in which molecules of a
fluid contact and adhere to the surface of a solid. By this process
gases, liquids, or solids--even at very small concentrations--can be
selectively captured and removed from air streams by use of adsorbent
materials. Commonly used adsorbents are activated carbon (charcoal),
silica gel. alumina, and bauxite. For practical reasons, activated
carbon is the one exclusively used for waste gas cleanup; the others are
used primarily for dehydration of air and gases.
Adsorption on Activated Carbon
The majority of radon-222 removal studies have centered on the use
of activated carbon for radon-222 adsorption (Li75). Findings of these
investigations can be summarized as follows:
o
Radon-222 gas can be adsorbed from air by various activated
carbons.
6-2

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°
The capacity of a given carbon to adsorb radon-222 depends on
the volumetric flow rate of air rather than on the quantity of
radon-222 (radon-222 concentration) adsorbed.
°
For maximum carbon bed utilization, air velocities should be
kept as low as possible. Air velocities between 0.5 and 2.5
liters/cm2-minute have been suggested.
°
The very small radon-222 concentrations in mine ventilation air
require increased contact time between the radon-222 and carbon
adsorbents, which, in turn, dictates relatively large carbon
beds to accommodate the low flow rates through the beds.
°
The capacity of a given carbon to adsorb radon-222 is reduced
by moisture in the gas stream and such moisture must be con-
sidered in system sizing and design.
°
The capacity of a given carbon to adsorb radon-222 is strongly
influenced by temperature. The volume of air cleaned per unit
of carbon mass decreases exponentially with temperature.
Applicability. The quantity of carbon materials (bed size) must be
sufficient to accommodate the low-level radon-222 concentration, humidi-
ty, and temperature characteristics of the mine ventilation air. Thus, a
major practical problem with activated carbon adsorption is the large
carbon bed size (and attendant pressure drop) necessary to clean the
ventilated air at the typical rates used in operating mines. Also. pre-
vention of re-entrainment of the radon-222 requires that the carbon bed
not only be of sufficient capacity, but that it be arranged in a manner
that will permit the radon-222 to decay before regeneration of the car-
bon.
The A. D. Little study (Li75) suggests that there is sufficient
adsorption capacity, even at 100 percent relative humidity and ambient
temperatures, to permit development of a practical air cleaning system.
Based on the given temperature dependency of activated carbon, this
report considered several different inlet temperatures in the development
of possible system designs. For inlet temperatures at ambient, 2°C, and
-20°C, an alternating two-bed system with cyclical charcoal regeneration
and a design effectiveness of 90 percent was used. For an air inlet
temperature of -80°C, a single-bed system (90 percent effective) was pro-
posed with a 12.7-day radon-222 retention time and needing no regenera-
tion. Both systems were designed for an air flow of 2.36 mS/s (5000
scfm) through 4660 pounds of charcoal for a I-hour period. A pressure
drop of 25 cm (10 inches) H20 was required to clean 500 pCi/liter of
radon-222 from a gas stream.
Costs. Estimated costs by Little (Li75) were based on the use of 72
of the 2.36-ms/s (5000-cfm) units described above, an annual UsOa produc-
tion rate of 590,000 pounds, and a total mine ventilation rate of
170 mS/s (360,000 cfm). Inflating the 1975 values to 1984 dollars gives
6-3

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costs of $18/pound of U30a (for the dual-bed system) and ~46/pound of
U30a (for the single-bed system). These values would equate to approxi-
mately $71 and $177 per ton of ore mined, respectively.
The radon-222 is retained
the carbon is then regenerated
waste streams of environmental
adsorption systems. Activated
mine for effective cleaning of
on the carbon until decay takes place, and
and reused; therefore, no byproducts or
significance are generated by carbon
carbon also could be applied within the
smaller volumes of air.
Adsorption by Molecular Sieves
Molecular sieve is a term used to characterize solid hydrated metal
crystalline materials, such as aluminosilicates. These aluminosilicates
(zeolites), both natural and synthetic, have been used in a variety of
processes for separating gases or liquids and as catalytic support mate-
rials. Molecular sieves have a high capability for surface adsorption,
either chemical or physical, and tend to adsorb polar molecules and
small-dimension atoms and molecules preferentially. For example, water
vapor can be removed very effectively by molecular sieves.
In general, the zeolite's mode of action is the preferential adsorp-
tion of small molecules that fit into the pores. Thus, radon-222 with a
relatively large atomic radius would be excluded from the normal zeolites
rather than captured. If a molecular sieve with a pore size large enough
to adsorb radon-222 were developed, all of the other atmospheric species
(°2, N2, H20, etc.) would also be retained. Thus, a molecular sieve
would have to have a greater preference for physically adsorbing radon-
222 than any of the other major atmospheric species. The activated
carbons are far superior to molecular sieves for adsorbing radon-222;
therefore, no further consideration should be given to molecular sieves.
6.2.2
Cryogenic Condensation
Radon-222, which has a normal boiling point of 211°K (-62°C), can be
collected by low-temperature condensation. Concentrations of radon-222
are low; therefore, the vapor pressure of radon-222 will be less than the
saturation vapor pressure until the temperature is reduced below the air
condensation point. Thus, cryogenic removal of radon-222 from air
requires that the radon-222-laden air be liquefied and stored until the
radon-222 has decayed.
Several cryogenic methods for removing radon-222 gas have been
suggested. In the Little report (Li75), two designs were proposed for a
radon-222 liquefier that would allow the radon-222 to decay as a liquid
in the reboiler or sparging condenser:
1)
Liquefying all input air before it enters the reboiler, where
the oxygen and nitrogen are continuously boiled away, leaving
behind the liquid radon-222.
or
6-4

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2)
Compressing the input air and allowing it
previously liquefied air as fine bubbles.
condenses and boils away. This method is
least 99 percent effective.
to enter a pool of
where the radon-222
estimated to be at
Costs. The estimated cost for the second method was $18 per pound
of UsOa produced (1975 dollars) (Li75). Inflated to 1984 dollars. the
cost would be $32 per pound of UsOa or $122 per ton of ore mined. The
application cited was for in-mine control and 50 percent operation. as
opposed to full-time operation required for control of mine ventilation
exhaust.
Applicability. Although cryogenic methods present no apparent
unusual engineering difficulties (since equipment for the liquefaction
process is readily available). this approach has not been attempted and
it is unlikely that this technique would be practical or cost-effective.
6.2.3
Separation
Semipermeable Membrane Separation
The industrial use of membrane separation has increased substantial-
ly in recent years--particularly with respect to separation of helium and
hydrogen from other gases. Successful application of membrane separation
depends on optimization of the ratio of permeabilities between the gas to
be separated by passing through the membrane and those that are to remain
in the original stream. The usual approach is to operate the system at
relatively high pressures and somewhat elevated temperatures.
The Little report suggests a multiple-stage system designed to
concentrate 90 percent of the radon-222 in 10 percent of the air flow
(Li75). The Little design for a 2.36-ms/s (5000-scfm) unit uses a seven-
stage cascade system consisting of 440 m2 (4728 ft2) of membrane in the
first stage and 651 m2 (7000 ft2) in subsequent stages, and it assumes
air can be pressurized to 60 atmospheres.
Costs. Estimated costs of this design (in 1975 dollars) are $61 per
pound of UsOa (Li75). Inflated to 1984 dollars, the estimated cost would
be $109 per pound of UsOa or $420 per ton of ore mined. This cost esti-
mate was based on in-mine control. two shifts a day, 260 days a year;
therefore. it is lower than would be required for a surface site and
continuous operation on total mine exhaust.
Applicability. The membrane areas and pressures required for this
method of radon-222 removal would be difficult to achieve in a mine ap-
plication. Also. all particulate matter in the gas stream would have to
be removed from the system inlet stream to prevent blinding of the mem-
brane surface. Most important. such a system concentrates the radon-222
in a waste stream, which would have to be stored, or cleaned before its
release to the environment. Thus, semipermeable membranes do not appear
to be a practical control technology for mine exhausts.
6-5

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Gas Centrifuge Separation
Separation of gases by the use of a centrifuge depends on the mass
difference between the gases being separated. The mass differences
between radon-222 and the major components of air (oxygen and nitrogen)
are seven and eight times, respectively. These sizeable differences
suggest that large separations of radon-222 from other exhaust air com-
ponents would be possible at reasonable peripheral speeds; however,
substantial difficulties are involved in utilizing gas centrifuge tech-
nology as a practical means of radon-222 control.
In their report (Li75), A. D. Little analyzed this technology and
concluded that... "the engineering feasibility of the technique appears
to be beyond the reach of the present industrial and technological capa-
bility..." They estimated the costs to be about $500,000 per pound of
UsOe (1975 dollars). Inflated to 1984 dollars, the estimated cost be-
comes $890,000 per pound of UsOe, or $3.4 million per ton of ore mined.
6.2.4
Absorption
Oxidation/Absorption
Radon-222, although a noble gas, is not completely inert and reacts
with strong oxidizing agents such as bromine trifluoride (BrFs) and
dioxygenyl hexafluoroantimonate (02SbF6). The concept of using these
agents to convert radon-222 to another form that can be absorbed in a
scrubber or on an absorption bed has been investigated by Argonne
National Laboratory. Kown et ale (Ko80) summarized their findings:
o
Liquid oxidant bromine trifluoride is very effective in oxidiz-
ing radon-222 from contaminated mine air. The reaction product
of radon-222 is a nonvolatile ionic compound and a liquid
scrubber may be used to react radon-222 with the oxidant;
however, the oxidant is very corrosive, toxic, and unstable,
especially in the presence of water vapor. The scrubber will
probably have to be made of corrosion-resistant material, and
the air will have to be dehumidified before scrubbing to mini-
mize the oxidant consumption.
o
Solid oxidant (02SbF6) reacts rapidly with radon-222 gas and
forms a nonvolatile radon-222 compound; hence, it can be used
for purification of radon-222-contaminated mine air by use of
the absorption bed concept. In the presence of moisture,
however, the oxidant is highly corrosive, toxic, and unstable;
therefore, the absorption system will have to be made of a spe-
cial corrosion-resistant material, and the contaminated air
will have to be dehumidified before treatment.
o
These concepts are still in the laboratory-investigation stage.
Many more laboratory tests and pilot plant investigations are
necessary to determine chemical consumption, side reactions,
6-6

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reaction products, handling property of the reactants and
product, types of equipment, equipment construction materials,
and design parameters.
Costs. No control costs have been estimated for these conceptual
systems; however, A. D. Little (Li75) did project costs for the use of
molecular sieves to remove the water in the inlet stream to overcome the
problem of chemical reagent consumption by reaction with water. Estimat-
ed cost (1984 dollars) of the water-removal system was $66 per pound of
U30a or $254 per ton of ore mined.
Applicability. Although the concept of radon-222 removal by reac-
tion with a strong oxidant appears technically feasible, the corrosive
and toxic nature of reactants and their instability in the presence of
moisture make this approach questionable from both a practical and eco-
nomic standpoint.
Solvent Absorption
Radon-222 is known to be more soluble in some organic solvents than
the major gaseous constituents in the air are; therefore, it would appear
that an effective scrubber system could be developed that would selec-
tively remove radon-222 from mine air. Problems with various scrubber
fluids (their volatility, toxicity, and/or flammability) have been iden-
tified (Li75). This report suggested dich1orodif1uoromethane (C12CF2)
(Fluorocarbon 12) as a possible solvent for this purpose, and the Oak
Ridge Gaseous Diffusion Plant has used Cl2CF2 in a 15-scfm pilot-scale
scrubber to capture radon-222 and other radioactive noble gases. This
compound is a gas at normal conditions; therefore, operation must be at
low temperatures or high pressures. (The Oak Ridge system operates at
100 to 600 psi and -45° to 25°C.) With respect to a suitable solvent,
Hopke et a1. recommends a systematic study of radon-222 solubility in
organic solvents to identify an effective and acceptable scrubber system,
and suggests perf1uorohydrocarbons as candidate compounds for meeting the
criteria of low toxicity, flammability, and vapor pressure (Ho84).
Costs. The Little report (Li75) cites an estimated cost (adjusted
for inflation to 1984 dollars) of $189 per pound of U90e or $728 per ton
of ore mined for organic liquid absorption.
Applicability. Although absorption by scrubbing may ultimately
become a technically feasible method, the lack of a suitable solvent
limits its possible use. If appropriate solvents are identified, other
problems (such as handling of radon-222-contaminated solvent and its
purification) must be addressed during the development of a practical
industrial-scale system.
6.2.5
Other Possible Methods
A hybrid system that combines the use of semipermeable membranes and
organic fluids presents some possible advantages. In such a system, the
radon-222 exiting through the membrane would dissolve into the fluid as
6-7

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it passed through to the other side and would be carried away for dis-
posal. The Little report showed relatively high temperatures (98°C) to
enhance permeability and the use .of toluene, a toxic, flammable liquid
(Li75). Costs were estimated to be $105 per pound of UgOS or $404 per
ton of ore mined (1984 dollars). In addition to the high costs, the
problem of identifying a safe, efficient solvent makes such a system
unattractive.
Several other systems combining adsorption, absorption, separation,
and cryogenic principles can be envisioned, but none offers promise for
development of a practical and economically acceptable system for radon-
222 removal from large-volume airstreams.
6.2.6
Summary
The chemical inertness of radon-222 makes the development of control
measures for mine exhaust application extremely difficult. The low-level
radon-222 concentrations and the large air volumes to be treated further
compound the difficulty, as does the presence of moisture and other
contaminants.
None of the radon-222 control technologies discussed have yet been
applied or appear ready to be applied to mine exhaust. In general, the
technologies are conceptual in nature, in an early developmental phase,
or in the laboratory-investigation stage. Uncertainties now exist re-
garding their applicability and effectiveness, and additional development
is required before these techniques will be ready for either pilot demon-
stration study or actual full-scale application. In some cases, labora-
tory tests and/or pilot study investigations are needed to determine what
kinds of equipment. construction materials. and design parameters are
needed. In other instances, development must await studies to identify
suitable collection media; to determine chemical consumption. side reac-
tions, and reaction products; and to examine methods of handling and
disposing of chemicals, reactants. byproducts, and the radon-222-bearing
concentrate captured by the systems. Table 6-1 summarizes the control
techniques discussed in this section.
Considering the current developmental status, their questionable
utility, and the high costs associated with their installation and opera-
tion. the technologies do not merit further consideration as practical
radon-222 control measures for total mine exhausts at this time.
6.3
Methods for Preventing Radon-222 From Entering the Mine Ventilation
Air
The two measures for preventing radon-222 from entering the mine
ventilation air are 1) preventing diffusion of radon-222 from the ore
surface to mine atmosphere, and 2) containing the diffused radon-222 in a
confined air space until it has decayed into less active products. The
first entails the application of sealant coatings over the exposed ore
6-8

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Table 6-1.
Summary of possible control techniques for radon-222
emissions in mine ventilation exhausts
Radon removal method
Adsorption systems
Activated carbon
tlolecular sievc"
Cryogenic condensatIon
0\
I
\.0
Separation systems
Semipermeable mem-
branes
Gas centrifuge
Absorption
~idation absorption
Solvent absorption
Hybrid system
Semipermeable
membrane and
organic fluid
Approximate
cOl'trol cost
per ton of
ore mined. 1984 $
71-77
3.4 x 106
>254
392
122
420
728
404
Remarks (current statu", major limitations. etc.)
Practical engineering constraint limits application to cleaning
flows that can reasonably be pulled through a carbon bed.
Requires development of a molecular sieve that preferentially
adsorbs rarlon over other atmospheric species (0,. N2. H20. etc.).
Activated carbon is currently superior to existing molecular
sieves.
Liquefied radon-air ~ixture must be stored until radon-222 has
decayed.
Radon-222-concentrated waste air must be stored or treated
before release.
Beyond current industrial/technoloRical capability.
l.aboratory-investigation stage anrl bench-scale studies only.
Requires further development, tests, pilot demonstration.
Suitable solvent with low toxicity, low flammability, low vapor
pressure mtlGt be found.
Solvent handling/purification problem. suitable liquid
required, and solvent storage/treatment required to dispose
of radon-222 by decay or other means.

-------
surface to form a gas-tight seal to inhibit radon-222 emanation, back-
filling of worked-out areas to reduce the exposed surface area, or over-
pressurization to limit radon-222 emanation. The second involves bulk-
heading mined-out areas to contain the radon-222.
6.3.1
Sealants
A few field tests have been conducted to evaluate the effectiveness
of different sealant materials in underground mines (Fr81a, Ha75). The
exposed ore and rock surfaces have many small fissures that allow faster
movement of radon-222 gas. Therefore, radon-222 can be prevented from
entering the mine air by applying a sealant over the exposed surfaces to
close these fissures and pore spaces. A three-coat system of selected
materials (a base coat of shotcrete followed by HydrEpoxy 156 and then
HydrEpoxy 300) was found to be effective in reducing radon-222 emissions
by 50 to 70 percent (Fr81a).
Although the use of sealants has the potential for partial control
of radon-222 in uranium mines, this approach is not practiced extensive-
ly. Development of sealants and field testing has been conducted in
recent years, but the application of sealants is limited to certain areas
of the mine, partly because of the effort involved in applying the seal-
ants to the ribs and back of a drift.
For adequate radon-222 control, sealants must provide an impermeable
boundary between the surface of the ore body and the mine atmosphere.
Heavy wire mesh is used to prevent rock falls in the drifts, and the
shotcrete must first be applied over the wire before a coating of sealant
is applied. This approach effectively stops the diffusion of radon-222
into the mine ventilation system. The radon-222 gas is retained on the
ore body side of the sealant, where it decays into its solid daughter
products.
Development and exploration drifts through the ore body can be major
sources of radon-222 and are well suited for coating with a sealant. The
sealants are used on the entire surface of the drifts. Dirt or other
material can be placed on the floor to protect the sealant. In the
room-and-pillar stope mining method, most of the drifts driven during the
stope development stage are mined out (destroyed) during pillar extrac-
tion; thus, the life of the sealant (and radon-222 control) is limited to
the time between stope development and mining, which ranges between 6 and
9 months at many mines.
Sometimes the haulage drifts are driven into the barren rock forma-
tion under the ore body rather than into the ore body itself, and the
ribs and backs of such drifts have very low radon-222 fluxes. Depending
on the type of rock and the presence of any residual radon-222 emissions,
areas such as intake airways, shops, lunch rooms, etc. are good candi-
dates for sealing. These areas must already have some means of reducing
radon-222 concentrations for worker exposure purposes. Also, the areas
are basically permanent structures; therefore, the control afforded by
sealing them is more long lasting than that produced by applying sealant
in the active portions of a mine.
6-10

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Potential Effectiveness
Uranium ore deposits appear'erratically in nature. For this reason,
each mine has a unique layout and mining plan and its own mining methods.
The characteristics of the radon-222 sources and emissions at each mine
also are different. Thus, the specific application of a control technol-
ogy must be considered separately for each mine. For evaluation of
control technologies, however, Kown et al. (K080) considered a reference
mine with modified room and pillar stoping and a production rate of 1,000
tons of uranium ore per day. Seventy-five percent of the drifts driven
during the development of the stopes were assumed to be sealed with a
three-layer application of coatings (shotcrete, HydrEpoxy 156, and
HydrEpoxy 300). The combination of these three coatings was estimated to
be 60 percent effective in the sealing of the surfaces to which they were
applied.
The Spokane Research Center of the U.S. Bureau of Mines performed a
screening study on 65 coating materials for potential use in underground
uranium mines (Fr81a). These materials were first screened for toxicity,
flammability, and the ability to reduce radon-222 emanation and then
some were actually used during several field tests. Several other tests
on sealants were carried out by Lawrence Livermore Laboratories (Ha75).
The findings of these investigations are summarized below:
o
Under carefully controlled laboratory conditions, many sealants
have extremely low permeation coefficients that theoretically
will provide a better than 100:1 attenuation of radon-222. The
presence of so-called pinholes, however, and the difficulty of
applying a perfect coating on an irregular ore surface reduce
the effectiveness of these sealants considerably.
o
Field tests suggest that water-based epoxies such as HydrEpoxy
156 and HydrEpoxy 300 are well suited for the underground mine
application. A three coat system (a base coating of shotcrete
followed by HydrEpoxy 156 and then HydrEpoxy 300) was found to
effectively reduce radon-222 by 50 to 75 percent. The shot-
crete is needed to eliminate cracks and to provide a better
base for the sealants.
o
The amount of sealants used varies considerably among different.
mines.
o
The amount of exposed ore surface (radon-222 source) that can
be coated with a sealant is limited. Drifts through the ore
body, which are major radon-222 sources, are best suited for
sealant coating. Most of the drifts in a modern uranium mine,
however, are destroyed as the mining progresses. In a room-
and-pillar stope mine, for example, most drifts driven during
the stope development stage are mined out (destroyed) during
pillar extraction. The sealant coating applied to these drifts
will thus have a limited life.
6-11

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Cost of Sealant Coating
Information was derived from the application of sealant to 49,200 m2
(530,000 ft2) of drift surfaces annually at the following rate of
application (K080):
Shotcrete
HydrEpoxy 156 -
HydrEpoxy 300 -
0.909 gal/ft2
0.018 gal/ft2
0.032 gal/ft2
Other reported estimates of sealant usage in different mines are (Fr78a):
Shotcrete
HydrEpoxy 156 -
HydrEpoxy 300 -
0.5 to 3.0 gal/ft2 at $0.25/gal
0.008 to 0.026 gal/ft2 at $7.36/gal
0.019 to 0.047 gal/ft2 at $6.40/gal
The annual costs developed by Kown et al. were $344,300 ($0.66/ft2) or
$1.45 per ton of ore removed. These costs are based on an average life
of 8 months for the sealant and a 60 percent reduction of radon-222 emis-
sions. Cost estimates of other sealants range from $0.30 to $1.10/ft2
(Fr81a).
Pacific Northwest Laboratory's recent study of 13 mines indicates an
average cost of $5.80 per ton of ore mined ($0.34/ft2) if 80 percent of
the surface is sealed (B184). The Bureau of Mines states that intake
airways, shops, lunchrooms, and any areas where radon-222 emanation rates
are high are candidates for the use of sealants (Fr79).
Sealant effectiveness is based on many assumptions and approxima-
tions. In one study, the estimated radon-222 emissions from an unsealed
ore surface were assumed to be 55 pCi/ft2-s or 4.75 x 10-6 Ci/ft2/day
(K080). Based on an average sealant life of 8 months and 60 percent re-
duction of radon, the use of sealant was assumed to reduce the radon-222
emanation from active stopes by 23 percent. This reduction (1.01 Ci/day)
represented 11 percent of the radon-222 emissions from the entire mine.
The use of a sealant life of 8 months was a conservative estimate, and it
is expected that actual sealant life will be much longer.
The active stopes would not be completely sealed. The intake air-
ways into the stopes could be sealed, but not the drifts into the stopes.
Mines that are developed completely in the ore zone could seal the drifts
as they advance toward the back of the mine to help provide cleaner air
throughout the mine and reduce emissions to the surface. Under these
conditions, the life of the sealant would be greater than 8 months.
Thus, the use of sealants as a radon-222 control measure has limited
application and can be considered only one component of an overall con-
trol strategy. A sealant program would have to be part of a careful
mining plan so the coating activity would not interfere with ongoing
mining activity or expose mine workers to a new group of materials that
evolve during sealant curing.
6-12

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6.3.2
Backfilling
Description of Technique
Backfilling involves the filling of a worked-out stope with waste
material brought down into the area from the surface. To fill as much of
the stope as possible (usually only 80 percent of the volume can be
filled), filling takes place at the highest accessible point in the stope
(Fr81b). The material used in backfilling, typically the sand fraction
of the classified mill tailings greater than 200 mesh, is conveyed to the
stope in a slurry.
The current practice of backfilling of worked-out areas in an under-
ground mine is for the purpose of ground support and stabilization. This
practice can be expensive; therefore, it is applied primarily when the
cave-in of mined-out areas would cause the surface above the stope to
subside. If no surface subsidence is expected, the mined-out stopes are
allowed to cave in without backfilling.
Backfilling usually occurs only after the required grade of the ura-
nium ore has been removed from a part of the mine and the mine operator
has no plans to go back into the same stope for further excavations. As
a result, the technique is not practiced at mines that use drift expan-
sion as the primary means of ore exploration. At those mines where back-
filling is practiced, an 80 percent reduction in the volume of the stopes
is normally achieved. A secondary benefit of backfilling can be a reduc-
tion in the overall radon-222 emissions from the area. Still another
benefit (to the mine operator) is a reduction in power consumption, as
the area no longer needs to be ventilated (Fr81a).
A study by the Bureau of Mines and Kerr-McGee Nuclear to determine
how effective backfilling mill tailings into the mine stopes is in the
reduction of radon-222 emissions indicated a net radon-222 reduction of
84 percent from the stope (Fr81b). The study was based on the results of
backfilling only one stope in a mine. Battelle Pacific Northwest Labora-
tories estimated an efficiency of 80 percent if classified mill tailings
and a layer of clean surface sands are used for backfilling (Bl84). The
average cost estimated by PNL was $12.64 per ton of ore mined.
6.3.3
Bulkheads
Bulkheading of mined-out areas is a common practice among mine oper-
ators. Bulkheads are simple air-restraining barriers used to isolate the
worked-out areas from active areas. This practice reduces radon-222 con-
centrations and thus allows the owner to reduce ventilation air require-
ments in the active areas. The bulkheads currently used in underground
uranium mines are intended for in-mine control of radon-222 decay product
concentrations and are not always airtight. The numerous different
designs range from brick and mortar to plywood.
Even though decay of the radon-222 is occurring behind the bulkhead,
the radon-222 flux of the enclosed area is of such a magnitude that an
6-13

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equilibrium concentration is quickly attained (see Appendix C). The
concentration of radon-222 behind the bulkhead has been reported to be
anywhere from 30,000 (Li82) to 300,000 pCi/liter (Fr78b), and some means
of preventing leakage into the active mining area must be established.
This can consist of a simple passive bleed vent leading to an exhaust
airway in order to balance the pressures between the enclosed area and
the active portion, or a bleed vent connected to an exhaust fan to create
a lower pressure behind the bulkhead with respect to the active area.
The air bleed must be an exhaust airway. In lieu of an air bleed, the
mine operator must rely strictly on the integrity of the bulkhead to
minimize any leakage. This mayor may not be effective, depending on the
permeation of radon-222 through the host rock. A vent system under
negative pressure ensures that any air leakage that occurs is into the
contaminated area rather than into the active mining area. Bulkheads
installed for reducing radon-222 emissions to the atmosphere, as opposed
to those installed to prevent radon-222 emissions into the active mining
areas, must be constructed with a tight seal (to reduce leakage). Bulk-
heads constructed for this purpose are shown in Figures 6-1 and 6-2.
The volume of a mine that is bulkheaded depends on several factors,
including the age of the mine, the ease of supplying ventilation air, and
ore exploration methods. The volume of worked-out areas in newly opened
mines is small, which limits the fraction of the mine that can be sealed.
In some mines, the last portion of the mine t.hat the ventilation air
passes through is the worked-out area. Thus, exposure to radon-222
accumulating in this area can be controlled by constructing an upcast
vent hole at that location. This allows the high radon-222 concentra-
tions to be vented directly to the surface without impacting the active
portions of the mine.
Exploration methods also have an impact on radon-222 exposure reduc-
tion methods in use. Some mine drifts are constantly being expanded for
exploration purposes rather than being abandoned and sealed. This is a
practice at some mines in the Colorado Plateau area. Temporary bulkheads
would be required in such mines, along with some means of ventilating the
inactive area before removing the bulkhead for additional exploration..
Bulkheading allows mine ventilation air rates to be reduced while
maintaining acceptable radon-222 decay product levels. Radon-222 will
continue to emanate into the closed-off area and possibly leak into the
active area as a result of barometric pressure changes, blasting shock
waves, and the like. Therefore, an adequate air flow out of the enclosed
area must be maintained and the bulkhead area must be kept under negative
pressure.
The use of bulkheading to reduce radon-222 emissions to the atmo-
sphere requires ventilation of the bulkheaded area at a rate low enough
to allow the radon-222 to decay behind the bulkhead before it is released
to the atmosphere. This can be accomplished by constructing a tightly
sealed bulkhead to ensure the maintenance of negative pressure
6-14

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Figure 6-1.
Example plywood bulkhead with plastic liner (Li82).
Figure 6-2.
Example bulkhead with coating (Li82).
6-15

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with a minimum air flow from the enclosed area. Equilibrium conditions
tend to cause the air bled to the surface from a bulkheaded area to have
high radon-222 concentrations (in a low gas flow). Thus, a point will be
reached at which an increase in the ventilation rate from the bulkheaded
area will result in no actual radon-222 emission reduction.
Technical Considerations
An important consideration that must be made in the implementation
of a bulkheading program is that of miner safety. Any activity conducted
in an underground mine, as well as materials used underground, must con-
form with existing MSHA regulations for protection of the underground
work force. These regulations will necessarily impact the design, con-
struction, and use of bulkheads in the underground mine work environment.
Current bulkhead construction practices vary with the type of rock
in which the mine is located, the degree of water control required, the
proximity of the bulkhead to exhaust airways, and the ultimate purpose of
the bulkhead. The basic bulkhead structure usually consists of a timber
or metal stud barrier covered with expanded metal lath or any of several
sheet products, such as plywood, wafer board, hardboard, or waterproof
gypsum board. The sheeting or lath is covered by spraying or troweling a
sealant onto the basic structure, the joint between the structure and the
rock, and the adjacent rock to form a continuous seal and radon-222
barrier.
There are essentially three functional parts to a bulkhead, and each
requires different properties. The primary part of the bulkhead is the
basic structure that fills most of the opening. This can be a relatively
rigid structure that provides primary resistance to mechanical abuse,
blasting shocks, pressure differ~ntials, etc. It may be a continuous
nonporous membrane itself, or it may support such a membrane (which might
be attached to this primary structure or sprayed onto it). The important
characteristics of this part of the bulkhead are 1) structural strength,
which must be maintained for an extended period in the mine-operating
environment; and 2) membrane continuity, i.e., it must not crack or
develop holes or leaks in the mine operating environment.
The second part of the bulkhead is the portion that forms the seal
between the primary structure and the rock wall of the opening. This
part, which is relatively narrow, is supported by the primary structure;
therefore, limited structural strength is required. Nevertheless, this
portion must provide a positive seal that can be maintained through
blasting shock waves, rock movement, running water, and other adverse
conditions of the mine operating environment.
The third part of the bulkhead is the surface sealing of the rock
for a distance of approximately 1 meter (3 feet) from the plane of the
bulkhead to minimize migration of the radon-222 around the bulkhead
through the rock. This seal must be of a material that will adhere to
and seal the surface of the rock even if it is damp. Positive sealing of
the rock surface must be maintained through normal movement of the rock,
6-16

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blasting, water influx, and other conditions that are part of mine opera-
tions.
All the air in sealed-off areas is free to move quite rapidly in
response to small pressure gradients; therefore, bulkhead leaks that
permit escape of the trapped air at only relatively slow rates (i.e., a
few cubic feet per minute) can easily increase radon-222 decay product
concentrations in the air of adjacent areas to unacceptable levels over
periods of hours, or even a few days. Chronic effects have been observed
in periods of repeatedly cycling barometric pressures and in situations
where large reservoirs of trapped (and highly radon-222-polluted) air
communicate, through leaky bulkheads and other routes, with relatively
small volumes of ventilation air (Mu82).
Some relief of positive-air-pressure conditions in sealed-off mine
areas can be achieved by simply opening a low-resistance air passage or
bleed vent between the bulkheaded area and a convenient exhaust airway.
A passive bleeder, however, can be only partially effective in overcoming
an environmentally (or artificially) induced pressure differential;
therefore, imperfectly sealed bulkheads may still leak to some extent
under the influence of the remaining pressure difference.
Several methods have been used to reduce the amount of uncontrolled
leakage into or out of an enclosed area and to limit the flow of the
bleedstream. Several researchers have found it necessary to apply seal-
ants to the ribs and back of the bulkheaded drift to limit permeation of
radon-222 around the bulkhead (Li82, Fr78b). A differential pressure
transducer has also been used to monitor the pressure differential across
a bulkhead (Li82). The transducer provides a signal to control the
operation of a forced-convection fan and thereby ensures that the desired
negative pressure differential is maintained.
Safe disposal of the exhaust air from a sealed-off inactive area can
present some problems, especially if the polluted air cannot be exhausted
directly into an isolated vent airway. The use of large-diameter vent
tubing of flexible fabric or plastic is not considered safe for conduct-
ing polluted exhaust air through occupied portions of the mine. This
kind of air conduit is best operated under positive pressure; therefore,
such a system would be exposed to the possibility of leaks, which would
result in contamination of the air around it. For operation under nega-
tive pressure, the exhaust vent tube must be made of some rigid material,
e.g., metal, fiberglass-reinforced plastic, or wire-wound plastic. Rigid
air conduits are not impractical, but neither are they widely used in
underground mines, largely because they cost more and are more suscepti-
ble to damage than flexible tubing.
Bleedstream cleanup with activated carbon has been suggested as an
alternative to its direct release to the atmosphere (BI84, Li82, Ko80).
This alternative may be able to provide an additional 95 to 99 percent
reduction in the radon-222 emission from the bleedstream (Ko80, B184).
Such a unit would obviously add cost and complexity to a radon-222 emis-
sion control program, and such a system has not yet been demonstrated
under actual mine conditions.
6-17

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Effectiveness
The success of a bulkheading program depends on the ability of the
mine operator to maintain as small a bleedstream flow rate as possible.
The technique is most applicable in old mines with large volumes of
worked-out areas.
The ability to achieve negative pressure in bulkheaded areas with a
minimum bleedstream flow is affected by the following factors:
o
Formation of cracks in the bulkhead/drift interface
o
The presence of fissures or longholes in the bulkheaded area
o
Flow around the bulkhead due to high permeability related to
the porosity of the host rock
Any of these conditions can cause the pressure in the bulkheaded area to
equilibrate with the pressure in the active mining area. This will re-
quire a higher flow rate out of the enclosed area to maintain a negative
pressure differential and will reduce the radon-222 emission reduction
potential.
Theoretical calculations were made to illustrate the effectiveness
of bulkheading in reducing radon-222 emissions. These calculations in-
volved modeling the radon-222 decaying in a mine area sealed with a bulk-
head. The model used a drift with a surface area of 66,890 m2 (720,000
ft2), releasing radon-222 into a volume of 59,450 m3 (2,100,000 ft3).
For these calculations a constant radon-222 flux rate of 9.29 pCi/ft2 per
second was used. The model does not take into account some important
factors, such as barometric pressure changes or declining concentration
gradient, which occur as the quantity of radon-222 increases. Therefore,
the results obtained from this model represent the upper boundary limits.
The results of these calculations are reported in Appendix C for
radon-222 concentrations (pCi/liter) in the sealed area, daily radon-222
decay (Ci), daily radon-222 removal (Ci), and the percent radon-222 decay
in the sealed area. The amount of radon-222 decay is a measure of the
emission reduction.
Four air removal rates are analyzed; there are percentages of total
volume of air in the sealed area which is removed per day. For a 10
percent removal rate, approximately 150 cfm is removed from the sealed
area. The following is a summary of the results of these calculations at
steady state:
6-18

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Air removal rate (%)
0*
10
20
50
Estimated radon decay (%)
100
64
47
26
*
In practice, a zero percent removal rate cannot usually be achieved be-
cause a completely tight bulkhead is difficult to construct. Air is
removed to maintain negative pressure.
Bulkhead Costs
The cost components of a basic bulkhead consist of materials and
labor for the construction of the bulkhead, the cost involved with moni-
toring and producing a negative-pressure differential, and labor and
maintenance for periodic maintenance and testing. Table 6-2 presents
estimated 1984 costs of these components. Assuming that any given volume
of a mine can be isolated with 10 bulkheads (Bl84) and that some compo-
nents of the bulkhead will require reconstruction every 6 months (worst
case), a bulkhead program yields an annual control cost of approximately
$41,000.
Table 6-2.
Cost of components of bulkhead construction
(1984 dollars)
Item
Total
Labor(a)
Materials
Preparation
Site selection and measurement
Precut material and transport
Construction
Framing
8 in. x 8 in. - 5 at 10 ft
2 in. x 6 in. - 4 at 16 ft
Plywood - 6 sheets at ~ in.
Surface cleaning
Grout
Floor - 4 sacks of cement
Ribs and back - 3 bags of plaster
Urethane bead - 3 gallons
Membrane (Aquafas) - 44 gallons
Cleanup
Subtotal
Vent duct (fiberglass) - 500 ft
Fan - ~ hp, 375 cfm
30
60
30
60
o
o
60
15
150
45
200
38
252
45
140
23
102
o
75
60
30
90
45
20
27
50
400
o
95
87
80
490
45
660
1422
762
60
15
1060
210
1000
195
Total 735 1957
(a) Based on $15/h including overhead and fringe benefits.
2692
6-19

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Activated Carbon System on Air Bleedstream
Application of an activated tarbon system for bleedstream radon-222
control entails an additional cost component. Detailed capital and
annual operating cost estimates for an activated carbon system to treat a
0.047-m9/s (100-cfm) bleedstream vent flow are provided in Appendix D.
These estimates indicate that a single activated carbon system will
result in an annual cost ranging between $67,000 and $85,000. Assuming
that one such system will be required for each of the 10 bulkheads, the
addition of bleedstream control will increase the annual cost of a bulk-
head program by $670,000 to $850,000. Although a credit is expected for
reduced ventilation air requirements, no credit is taken because of cur-
rent practices. It is also assumed that existing bulkheads would require
reconstruction; therefore, no credit is taken for existing bulkheads.
In conclusion, although bulkheads have the potential to reduce
radon-222 emissions, such reductions are achievable only with careful at-
tention to bulkheading practices. Based on the considerations presented
in this section, the cost of a program in the reference mine would be
$0.37 per ton of ore mined. Additional control afforded by continuous
activated carbon adsorption of the bleedstream would increase the cost
substantially by $6 to $7.60 per ton of ore.
6.3.4
Mine Pressurization for Radon-222 Control
Positive mine pressurization has been tried several times to force
the radon-222 in the mine atmosphere back into the walls of the mine.
One researcher found no effect from exhausting vs. blowing ventilation
(Th81). In general, these efforts have been successful in reducing the
radon-222 concentrations in the mine itself. An "air" sink is necessary
to accept the radon-222. If the radon-222 is forced through the ore body
or surrounding area to the surface, it can decay before coming to the
surface. If the area is impermeable, however, radon-222 will return to
its previous levels. In tests by the Bureau of Mines, the radon-222
levels in the mine were reduced by 20 percent (releases to the atmosphere
were not determined). The surrounding soil must be permeable enough to
hold radon-222 and allow for its decay, but not so permeable so as to al-
low significant increases in surface emissions. In a recent EPA report,
it was concluded that positive-pressure ventilation was not effective in
reducing atmospheric emissions of radon-222 (EPA84). Another researcher
found that although an immediate radon-222 reduction is obtained as a
result of overpressurization, the radon-222 flux soon returns to levels
observed prior to application of mine pressure (Sc66).
6-20

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B184
EPA84
Fr78a
Fr78b
Fr81a
Fr81b
Ha75
Ho84
Ja79
REFERENCES
Bloomster C. H., Enderlin W. I.. Young J. K.. and Dirks J. A.,
Cost Survey for Radon Daughter Control by Ventilation and Other
Control Techniques, prepared for the Bureau of Mines by
Battelle Pacific Northwest Laboratory. Richland. Washington.
under Contract J0215033. 1984.
Environmental Protection Agency. Radionuclides:
Information Document for Final Rules. Volume II,
022-2, Office of Radiation Programs, Washington,
1984. .
Background
EPA-520/1-84-
D.C., October
Franklin J. C., Meyer T. 0., and Bates R. C., Barriers for
Radon in Uranium Mines, Bureau of Mines. RI-8259. 1978.
Franklin J. C.. Musulin C. S., and Thebeau D. W., Research on
Bulkheads for Radon Control in Mines, presented at the Second
Conference of Uranium Mining Technology, Reno, Nevada, 1978.
Franklin J. C., Control of Radiation Hazards in Underground
Uranium Mines, in Radiation Hazards in Mining: Control, Mea-
surement, and Medical Aspects. M. Gomez. Editor, Kingsport,
Tennessee. 1981. pp. 441-446.
Franklin J. C., et al., Radiation Hazards in Backfilling With
Classified Mill Tailings, presented at the Central New Mexico
Section AIME Fifth Annual Uranium Seminar, Albuquerque, New
Mexico. 1981.
Hammond J. G., Ernst K., Guskill J. R., Newton J. C.. and
Morris C. J., Development and Evaluation of Radon Sealants,
Bureau of Mines Contract Report H0232047, 1975.
Hopke P. K., Leong K. H., and Stukel J. J., Mechanisms for the
Removal of Radon from Waste Gas Streams, EPA Cooperative Agree-
ment CR 806819, UILU-ENG 84-0106, Advanced Environmental Con-
trol Technology Research Center. 3230 Newmark Civil Engineering
Laboratory, 208 North Romine Street, Urbana. Illinois 61801,
March 1984.
Jackson P.O.. et al., Radon-222 Emission in Ventilation Air
Exhausted From Underground Uranium Mines, Report No. NUREG/CR-
0627, PLN-2888 Rev. Battelle Pacific Northwest Laboratory.
Richland, Washington. 1979.
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Ja80
Ko80
Li75
Li81
Li82
Mu82
Sc66
Th81
Jackson P.O., et al., An Investigation of Radon-222 Emissions
From Underground Uranium Mines, Report No. NUREG/CR-1273,
PNL-3262 Rev. Battelle Pacific Northwest Laboratory, Richland,
Washington, 1980.
Kown B. T., Van der Mast V. C., and Ludwig K. L., Technical
Assessment of Radon-222 Control Technology for Underground
Uranium Mines, Office of Radiation Programs, U.S. Environmental
Protection Agency, Washington, D.C., April 1980.
Arthur D. Little, Inc., Advanced Techniques for Radon Gas
Removal, Bureau of Mines OFR 60-75. Arthur D. Little, Inc.,
Cambridge, Massachusetts, 1975.
Arthur D. Little, Inc., Sealant Tests to Control Radon Emana-
tion in a Uranium Mine, Bureau of Mines Contract J0199041,
Washington, D.C. 1981.
Arthur D. Little, Inc., Evaluation of Bulkheads for Radon
Control, Bureau of Mines Contract H0212003, Washington, D.C.
1982.
Musulin C. S., Franklin J. C., and Thomas V. W., Effect of the
Diurnal Cycle and Fan Shutdowns on Radon Concentration in an
Experimental Uranium Mine, Report No. RI-8663, U.S. Bureau of
Mines, Spokane, Washington, 1982.
Schroeder G. L., Evans R. D., and Kraner H. W., Effect of
Applied Pressure on the Radon Characteristics of an Underground
Mine Environment, Society of Mining Engineers, Transaction,
25(1):91-98, 1966.
Thomas V. W., Musulin C. S., and Franklin J. C., Bulkheading
Effects of Radon Release From the Twilight Uranium Mine, pre-
pared for U.S. Department of Energy under Contract DE-AC06-
76RLO-1830 by Battelle Pacific Northwest Laboratory, Richland,
Washington, January 1981.
6-22

-------
APPENDIX A
LIST OF UNDERGROUND URANIUM MINES
A-I

-------
LIST OF UNDERGROUND URANIUM MINES (DOL84)
State
Company name and address
Arizona
Energy Fuels Nuclear, Inc.
P.O. Box 36
Fredonia, AZ 86022 .
Colorado
Phil Bunker
1092 Montana St.
Nucla, CO 81422
~
I
N
Cleghorn Mining Co.
P.O. Box 2604
Grand Junction, CO 81502
Cotter Corp.
9305 W. Alameda Pky.
Lakewood, CO 80226
Cotter Corp.
P.O. Box 700
Nucla, CO 81424
Robert M. Hurst Mining
P.O. Box 238
Dove Creek, CO 81324
Mine name
County
Status(a)

Permanentaly closed 7(~y(b)
Active (14 employees)
Permanently closed 8/84
Active (25 employees)
Kanab North
Hacks Canyon 2
Hacks Canyon 1
Pigeon
Mohave
Mohave
Mohave
Coconino
Mineral Joe No.2
Permanently closed 7/84
Montrose
Rex 38
Permanently closed 3/84
Montrose
Schwartzwalder
Jefferson
Active (152 employees)
C-CM-25  Montrose Temporarily closed 8/84
C-SR-13A  Montrose Temporarily closed 8/84
C-LP-2  Montrose Temporarily closed 8/84
C-JD-7  Montrose Temporarily closed 7/84
C-JD-9  Montrose Temporarily closed 4/84
C-SM-18  Montrose Temporarily closed 8/84
C-LP-22A  Montrose Temporarily closed 8/84
Black Jack Summit San Miguel Permanently closed 3/84

-------
State
Status(a)
Company name and address
Mine name
County
Colorado
(cont. )
>
I
W
New Mexico
Jones Mining Co.
P.O. Box 32
Bedrock, CO 81411
Kelmine Corp.
P.O. Box 272
Naturita, CO 81422
Kelmine Corp.
P.O. Box 1383
Moab, UT 84532
Minerals Recovery Corp.
2801 Youngfield No. 221
Golden, CO 80401
Rajah Ventures, Ltd.
P.O. Box 2360
Grand Junction, CO 81522
Sage & Sage Mining
P.O. Box 323
Naturita, CO 81422
UMETCO Minerals Corp.
P.O. Box 508
Dove Creek, CO 81324
Bokum Res. Corp.
P.O. Box 13958
Albuquerque, NM 87192
Cobb Resources Corp.
313 Washington, SE
Albuquerque, NM 87108
JB4
C-JD-6
Duggan Adit
Pickett Corral
Sun Cup
Dolores River
Centennial
Horseshoe
October
Pack Rat
Betty Jean
Dermo-Snyder
Marquez
Section 12
Montrose
Montrose
Montrose
Montrose
San Miguel
San Miguel
San Miguel
San Miguel
Mesa
Mesa
Montrose
San Miguel
McKinley
McKinley
Permanently closed 3/84
Temporarily closed 7/84
Temporarily closed 8/83
Temporarily closed 1/84
Temporarily closed 1/84
Temporarily closed 1/84
Active (9 employees)
Temporarily closed 1/84
Permanently closed 3/84
Temporarily closed 4/84
Permanently closed 7/84
Temporarily closed 8/84
Temporarily closed 2/84
Temporarily closed 4/83

-------
 State Company name and address  Mine name  County  Status(a) 
 New Mexico Gulf Mineral Resources Co. Mt. Taylor  Cibola Temporarily closed 3/84
 (cont.) P.o. Box 1150          
  Grants, NM 87020          
  Homestake Mining Co. Section 23(d)  McKinley Active (169 employees)
  P.O. Box 98  Section 25(e)  McKinley Temporarily closed 11/83
  Grants, NM 87020  Section 13  McKinley Temporarily closed 10/81
  Phillips Uranium Corp. Nose Rock No. 1 McKinley Temporarily closed 6/83
  P.O. Box J          
  Crownpoint, NM 87313         
  Quivera Mining Co.   (e)  McKinley Active (12 employees)
  Section 17(d) 
  P.O. Box 218  Section 19  McKinley Active (63 employees)
>  Grants, NM 87020  Church Rocfd~o. 1 McKinley Active (48 employees)
I    Section 24(d)  McKinley Active (12 employees)
~     
    Section 30 d McKinley Active (76 employees)
    Section 30(~,st() McKinley Active (59 employees)
    Section 33(d)  McKinley Active (12 employees)
    Section 35  McKinley Active (102 employees)
    Section 36  McKinley Active (81 employees)
  Sohio Western Mining Co. L-Bar   Valencia Active (18 employees)
  P.O. Box 25201          
  Albuquerque, NM 87125         
  Todilto Explor. & Dev. No. 2 - Piedra  McKinley Permanently closed 6/84
  3810 Academy Parkway, S. Triste       
  Albuquerque, NM 87109         
  UNC Mining & Milling Ann Lee(e)  McKinley Temporarily closed 6/83
  P.O. Drawer QQ  NE Church(~~ck(d) McKinley Temporarily closed 3/83
  Gallup, NM 87301  Sandstone  McKinley Temporarily closed 6/83
    St. Anthony  Valencia Permanently closed 12/83
    Old Church Rock McKinley Temporarily closed 6/83

-------
State
Status(a)
Company name and address
Mine name
County
New Mexico
(cont.)
Utah
>
I
\J1
Western Nuclear, Inc.
P.O. Box 899
Thoreau, NM 87323
Atlas Minerals
P.O. Box 1207
Moab, UT 84532
Ronald E. Beck
4451 E. Easy Street
Moab, UT 84532
Cleghorn Mining Co.
P.O. Box 2604
Grand Junction, CO 81502
Cotter Corp.
9305 W. Alameda Pky.
Lakewood, CO 80226
Cotter Corp.
P.O. Box 700
Nucla, CO 81424
Energy Fuels, Nuc., Inc.
P.O. Box 59
Green River, UT 84525
Garth Noyes
Tickaboo, UT 84734
Homestake Mining Co.
1726 Cole Blvd.
Golden, CO 80401
Ruby Nos. 3 & 4
Pandora
Rim
Velvet
Pappy No.1
Blue Cap
Bi-Centennial
Thornburg Memorial
Sahara
Trackyte No.5
LaSal No.2
McKinley
San Juan
San Juan
San Juan
Grand
San Juan
Grand
Grand
Emery
Garfield
San Juan
Active (31 employees)
Temporarily closed 3/84
Temporarily closed 3/84
Temporarily closed 3/84
Permanently closed 6/84
Active (7 employees)
Active (8 employees)
Active
Temporarily closed 8/81
Temporarily closed 1/84
Permanently closed 8/84

-------
 State Company name and address Mine name County  Status(a)
 Utah (cont.) Kelmine Corp.  Cub San Juan Permanently closed 6/84
  P.O. Box 1383     
  Moab, UT 84532    
  Pene Mining Co. Little Eva Grand Permanently closed 4/84
  P.O. Box 16     
  Thompson, UT 84540    
  Plateau Resources, Ltd. Lucky Strike Garfield Active (26 employees)
  P.O. Box 511     
  Tickaboo, UT 84734    
  Rio Algom Corp. Lisbon San Juan Active (63 employees)
  P.O. Box 610     
»  Moab, UT 84532    
I         
0'\         
  Rio Algom Corp. Mivida San Juan Active (14 employees)
  P.O. Box 619     
  Moab, UT 84532    
  Shumway Mining Monte Cristo Grand Permanently closed 7/84
  P.O. Box 443     
  Moab, UT 84532    
  Glen A. Shumway Strawberry San Juan Permanently closed 3/84
  P.O. Box 322     
  Blanding, UT 84511    
  T&J Mining  Red Vanadium Grand Permanently closed 2/84
  371 Wingate     
  Moab, UT 84532    
  T.S.&R., Inc.  Redrock San Juan Permanently closed 2/84
  2125 Canyonlands    
  Moab, UT 84532    

-------
State
Company name and address
Mine name County Status(a)
Wilson Silverbell San Juan Temporarily closed 3/84
LaSal San Juan Temporarily closed 3/84
Hecla Shaft San Juan Temporarily closed 3/84
Snowball San Juan Permanently closed 4/84
»
I
-....J
UMETCO Minerals Corp.
P.O. Box 1049
Grand Junction, CO 81501
Union Carbide
P.O. Box 1029
Grand Junction, CO 81501
Utah Mineral Dev.
350 Park Rd.
Moab, UT 84532
Western Key Enterprise, Inc.
3080 E. Spanish Trail
Moab, UT 84532
Wyoming
Pathfinder Mines Corp.
P.O. Box 831
Riverton, WY 82501
Bandit
Permanently closed 6/84
Silver King Mines, Inc.
P.O. Box 560
Casper, WY 82601
Western Nuclear, Inc.
Jeffrey City, WY 82310
San Juan
Geo No.1
Temporarily closed 4/83
Montrose
Lucky Mc 7B
Four Corners
Active (5 employees)
Active (6 employees)
Fremont
Fremont
Golden Eagle
Active (24 employees)
Converse
Sheep Mountain
Active (21 employees)
Fremont
(a) Status of underground uranium mines as of October, 1984.

(b) Date indicates when mine was closed.
(c)
Number of employees at active underground uranium mines.
(d)

(e)
Production supplemented by mine-water recovery (NM83, NM84).
Production from mine-water recovery only (NM83, NM84).

-------
REFERENCES
DOL84
Department of Labor, 1984 Uranium Mines Address Listing with
Workers and Employee-Hours, Mine Safety and Health Administra-
tion, Health and Safety Analysis Center, Denver, Colorado,
November 21, 1984.
NM83 New Mexico Energy and Minerals Department, Annual Resources
 Report, 1983 Update, Santa Fe, New Mexico, 1983. 
NM84 New Mexico Energy and Minerals Department, Annual Resources
 Report, 1984 Update, Santa Fe, New Mexico, 1984. 
A-8

-------
APPENDIX B
DATA FOR USE IN ESTIMATING POPULATION RISKS
TO INDIVIDUALS NEAR UNDERGROUND URANIUM MINES
B-1

-------
INDUSTRIAL SOURCE COMPLEX LONG-TERM MODELING RESULTS FOR REFERENCE
UNDERGROUND URANIUM MINE, MODELED WITH PLUME RISE
(Table B-1)
B-2

-------
",OOEl SP.LH,,,
Table B-L
15-JaN-1985 loi01
'.0. I
.... I$CLT ee....e..e...
I, PROG. DIVIDES BY
5.IIQOO TO NORMALIZE
"Od,1 Mln' ~Ith Plu~, Rf.., 8t.ck R"...,. (MOOELIP.SOR)
........ PAGE
... IU,,~jf"G - F~£). OF I)CCUHRENCE OF SPO VS. IIIR IS NOT 1.0 FOR SEASOti
. ISCLT INPUT DATa.
td
I
UJ
All Mi.lft!
STAIf Il ITY
STaPllITf
uaUllI n
STU:llITY
1T'''IUff
STatilLin
NIJ'WE II OF SOORCE 3. 5
'II"DEP 'JF ( HIS C'III) SUTEH
~U~REQ OF V '-15 CillO SVSTEM
NU~~ER OF SPECIAL POINTS.
NV"~EP 0' SEASOHS. I
IIU 'IIEP OF ftI!1U SPEED CLUSES' II
'II!"~E~ OF 5TA:.ItlITY CLaSSES. II
.1\.I"ljEP 0' 111'1(' lIIRECT'.:JN CLASSES' III
FILE I'jIJ"'SER OF "'14 FILE "5EO FOR REPORTS .
TH[ ~~lG~A~ IS RUN I~ RURAL HOOf
CO~'CE"TPATI'J"I (DEPOSITIO'I) U!'1TS CONVERSION 'ACTOR '0.31109"9E+02
ACCEL£PI'IO~ \.IF GRAV'TY (H[TEFS/S£C..Z). 9.800
HEIG~T OF ~~A3UPEHENT OF "I NO SPEEO ("ETERS). 1.000
EI;T"'I""ENT PAP-AaETE;'! FON U"'STA8L~ CONIIITIONS . 0.1100
E'lr~"alll"ENT PINA1fETEit FOR STArtLE CCIIDITIONS . 0.600
COP~ECTIO~ IhGLC FOR GRID SYSTEM V~RSIJS DIRECTION DATA ~ORTH (DEGREES)
nEClv CUEFFICIENT 'O.OQOO~OOOEtOO
PP'!GPat :JPTJO'J S;jl TCHES . I, Z, I, 0, 0, 3, l, l, 3, II, 0, 0, 0, 0, 0,
Ill. SO"hCES I.<'E IJ5EO TO FO~'-' SII'JRCE CO.teJN'TION I
'H"GE ( ul:i G"I" SV'HE" POI',TS ('iETERS )' lOO.OO,
50~~.OO, 1poo.00, 8000.00, 9000.00, 10000.00,
lIEIRI';r, y A.IS Gr.IO SYSTEH POI~lfS (DEGREES)' O.o~,
1]5."" 151.50, 1'0.00, 20Z.50, lZ5.00,
POINY, .
PUINTS .
o
15
III
.
0.000
1 ....
0, 0, I, 0, 0,

500.00, 1000.00, lOOO.OO, 3000.00, QOOO.OO,
15000.00, lOOOO.OO, 30000.00, 50000.00,
2l.'0, :"115.00, 111.50, 90.00,
241.50, 210.00, 19l.'0, 515.00,
SE '501,
. A~BIENT ~IR TEHP£RATUR£ (DEGR!ES KELVIN) .

STAOILITV STARILITY STABILITY STABILITY STA91LITY STAelLITY
caTE~apv 1 CLTEGORY Z CATEGORY 3 CATECORY . CATEGURY 5 CATECORy .
Zi~.e30o leh.~3no 2811.5JOO l811.B300 2811.B500 2811.8100
C'T("flRY
CHEC'-"!'Y
C,TEC,;lIf
tlTEC'1C:f
(lTEIO;'Pf
C.'ECORY
. ~[.ING LAYER "EIGHT (METER') .

SEABON I
.I~O SPEE~ .I"'~ SP~EO NI~D SPEED -IHD SPEED WIND 8P!£0 MIND SPEED
CATEGOPy 1 CATEGO~Y l CATEGUPV 1 CATEGORy Q CATEGORY 5 CATEGORY II
ItI.luonOQ'tnoO.loonOOE+1I40.100oonE+040.100000f+OQO.100000E+040.100000E+OQ
ZO.IPOO~OE.~qO.IUOOO~E.~10.IOOOooE.040.100000E.oa~.lno000£.040.100000E.0'
'O.lon~nr.E.~1n.lno~ooE,ooO.lononoE+040.loonooEtllon.100000E.OOO.100000£+04
Qn.I'oonn~.oQn.10~OOOEtCoO.lonoooEt040.lonoonE+OQn.I"0oOOE.040.10"000E+00
50.loroouEt050.100000E+050.lonnOllfe050.10000oEt050.11I0000£.050.100000Et05
bP.lr'000f.0'0.10000nfen50.100oooEe05n.loooooft05n.100000E.050.100000£+0'
112.'0,
))1.50,

-------
'400HS".LST,1I
Table a-I.
15-JA~-1~85 10101
'.\1. l
Wodel ~I". with ~lu". AI.., St.ck A.I..... (HOOELSP.SOA)
***. ISClT ..*.....**.,.
- 15CLT INPUT DATA (CO~T.) -
******** PAG!
- 'KEJUENCY O~ OCCURqE~CE OF NINO SPEED, OIRECTIOII AND STABILITY -
SEASO~ 1
STABILITY CATEGORY I
   w(rl['l SPEED IIltlO SPEED NINO SPEED MIND 8PEED NINO SPfED NI~D SPEED
   C HEGClP.Y I CATEGI1RY 2 CATEGORY J CATEGORY 4 CATEGORY 5 CATEGORY'
 rlf;>E C1 111"1 ( I). 7501'HP5) ( 2.o;oOOt'!PS)( 4.]000HPS)( ..8000~PS)( q.5000HPS)(12.S000~PS)
 (C-:C,fiHSI        
 '1. 'H'!':  0.O~0]~108 O~OOOOOOO(l 0.01)000000 0.110000000 0.00000000 0.00000000
 n.')o"  O.0~O]~108 0.00000000 0.000"0(\110 0.00000000 0.00000000 0.00000000
 lIo;.O~O  (I. (1.)000000 0.000(\0000 0.00000000 0.00000000 0.(\0000000 0.00000000
 !>7.5'"  0.(\"':101'000 0.00000000 0.0(\000000 0.00000000 0.(0000001) 0.00000000
 ~o.(\tI'  (\.aul)l~'S5G 0.0(\000000 0.000000(\(\ 0.00000000 0.000(\0000 0.00000000
 11<'.511(\  ll. OI~OllllOCO 0.0001"5511 0.00000000 0.00000000 0.00000000 0.00000000
 1]0;.001-'  o.'."..OII1SSI1 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
 10;7.SlIo  O. :'OC'S!'b.] 0.0(1000000 0.00000000 0.00000000 0.00000000 0.00000000
 I.' (). II II 'I  0.11"0117771 0.000]Qt(l8 0.00000000 0.00000000 0.0(\000000 0.0000000/1
 20;.5('11)  0.(\111178217 0~0",)H217 0.00000000 0.000011000 0.00000000 0.00000000
 2;».01);)  0."(107/0<'17 0.0(\1'l7711 0.00000000 0.000(\0"00 0.110(\00000 0.00000000
b:I 1'I1.SI),1  0.o1l23GbSO 11.001178217 0.00000"00 0.00000000 0.0000011'10 0.00000000
I 270.01lll  0."nO)QI08 "~0"Ub87Q 0.001100000 0.00000000 0.00000000 0.00001100(\
.l:'- zoZ. 5"11  11.I\I10J7d217 O.OOOI'lC;SIf 0.0(11)110000 0.000110000 0.1)0000000 0.00000000
 H'5.01l~  tI.~I\I>tQSC;1I 0.00111525 0.00000000 0.00000000 0.110000000 0.00000000
 H7.S'I1)  (I. ')('OS/llIb3 0.O(lo1Q554 0.'100"0000 0.00000000 0.0011001100 0.00000000
      SEASON 1   
     STABILITY CATEGORY Z  
iHl:uunrl
(n~(;~HS)
v.or~
U.51111
115.UO(l
1>7.';;0(\
C;~.\J"O
"c.'501\
IH.U"O
I~7.500
1 ~". CO.,
lOc.5.''''
c:<''5.0IJI1
cU7. '5('.)
<'70. Cl''''
i'..2.50~
315.IIUO
3J7. '1"')
"I~I" t\PEEO wJ~O SPEED WJ'IO SP£!D III~O S"EED IIr~o SPEED "I~O .,EEO
C'T~r,np.y 1 C.TfGO~Y 2 caTEGORY] caTEGORY 4 CATEGORY 5 CATEGO~Y 6
( 0.7S0Qt'F5)( 2.5000"P5)( 4.3000"PS)( ..8000~PS)( 9.5000MPS)(12.5000"PS)
". 01l1J3'J ",~ 1I.000'l7111 O.OIJOrooooo 0.11'1000000 0.00000000 0.00000000
(I. o (I 0 '5i\/,1) 3  0.000514663 0.001)1'l5S11 0.00000000 0.00000000 0.00000000
".""\J]QII\~ f..ooIl3010~ 0.n1J01'l5511 0.00000000 0.01)0001)00 0.00000000
0.(1('1101111,)0 o.00('51'h3 0.00'.100000 0.1100011000 0.00000000 0.00000000
0.U(l100uII0 l'. 0011 1 oS511 O.IIOOOOtlOO 0.00000000 0.00000000 0.00000000
0.011111'15511 0.0110001100 0.001)00000 0.00000000 O.UOOOOOOO 0.00000000
II.OII(lS8!>bJ I).O'lI)I'l5'5Q 0.(1111)00000 ".000001100 0.00000000 0.00000000
o.0"I1S'lA8 0.OOO]'l108 0.0001'lS511 0.110000000 0.00000000 0.00000000
(\.)0<']4,SO II.OIII'lS542 0.000'100110 O.OOO'lI)O/}1I 0."0000000 0.00000000
1).1<'131,1'1" u.0IlZIS0'lb 0.00'13'1108 0.00000000 0.00000000 0.00000000
O. \111318 Z I 7 11.(11\01"217 0.lIooJ'l108 0.000Iq5s11 0.00000000 0.00000000
1).""'I)Q7771  (1.,)(\ 17Sq.l\8 0.01)01'l!iS4 0.011000000 0."0000000 0.00000000
U.Ul'~07771 0.0/}IIHi!5 0.01lU105S4 0.000001)00 0.(11)000000 O.OOOUOOIIO
O.')IIII1\IS 0.00 )Q7771 0.1101100000 0.000110000 0.00000000 0.00000000
o.OIl"?!?17 O. IIIIlSlf21111 0.(\001)0"00 0.00000000 0.000000011 0.011000000
0.11"1176217 0.II015b4H 0.(1)011'101)0 0.000000011 0.1100000011 0.0000'1000
Z ****

-------
"OD£U,p.LST,O
Table B-1.
15-JAH-I'85 loi01
'801 J
MDd,1 "t", ~tth Plu~, At.l, 'tlck ~II""I C"DDELSP.SOR)
- ISCLT INPUT DATA (CONT.) -
] ....
.... ISClT .............
........ PAGE
O;j
I
V1
OJ'IECTIO"
(r'EGJ-US)
o. (10(-
20'.5/)1'
"5.CO/}
"'.50n
Ql'.OOr.
tIZ.5"~
13~.~ol'
157.511\'
II:' J. 01'1'
Z"c.51'0
2<'5.0l'J
l07.5u~
2H.H'O
2ai.5"~
)1!i.Ou'!
3J7.5"(
li I REC T I 0'.
(!.'EGf'EES)
,').or~
l?!onr.
QS. "(h'
117.5''''
q". (.no
II 
-------
Table a-I.
IIUDllSP .lS T, II
15-JAN-lq~5 loi01
"'D' 4
.... 'self .............
Hod,I "f~. ~fth Plum. Af.., St.ck AII".e. (MDDElSP.SOA,
........ PAGE
II ....
- ISelT INPUT DAT& (CONT.) -
- F~EQUENCY O~ OCC~RRENCE 0' ~IND SPEED, DIRECTION AND STABILITY -
Sf &!IO" I
STARIlITY C&TEGORY 0;
  WI!;I) SPfED ~IH[\ SPEED IHND SPEED IIINO SPEED WIND SPEED WINO SPEED
  e A TI'':GORY I CATEGORY l C&TEGOIIY) CATEGORY II CATEGORY 5 r.&TEGORY 6
 [lJ~ECflC~' (U.7500~PS)( 2.500~HPS)( Q.]OO~MPS)( b.6000HPS)( q.5000MPS)(12.5000MPS)
 O'fliqEfS)      
 J.O~O 0.01055"Z5 0.Ulu55f125 11.011]]21121 0.000fl1711 0.00000000 0.00000000
 lZ.50~ U.01851bl1b 0'.0060611f1 0.OUOq7111 0.0001'1554 0.00000000 0.00000000
 115.CI10 ~.IJIZ5111~7 ~.0~l]4b50 0.00078Z17 0.000iq5S4 0.00000000 0.00000000
 117.500 0.01lICl5~" O.oJ~11 Hl5 0.0005866) 0.00018217 0.00000000 0.00000000
 '1u.Ooo (I.015b'I]111 O. 0025!12!!4 0.0005'661 0.00000000 0.00000000 0.000000110
 112.5(10 0.JoId~oS2q 0.OU~Clq7116 O. 00iUII650 0.0005(!f>63 0.00000000 0.00000000
 1'5.0011 0.',o'!21?75 0.00')61>625 0.00Ub8H 0.000Iq5511 0.00019554 0.00000000
 157.51'10 0.007&2b13 0.lI0]"I'>'3 0.0013b8H 0.C003qIOS 0.000195511 0.00000000
 I~C.OU(t 0.0.17b"bl J 0.01Jb45l8S 0.00S06408 0.'>0273758 ' 0.000Iq5S11 O.OOOOOOGO
 7~2.5(),' !I.~I\]'J15Zq 0.uu1821b1 0.007111058 O. OOQQq7Qb 0.00078l! 7 0.00000000
 i'2~.0"0 (1.1)050'10)8 0."0'1"9706 0.~01l8'"511 0.~02qH1J 0.00Q3qI08 0.00000000
 2'17.50l' 0.(1)411"7I1b 0.0~508408 O.00'527'1b) 0.0072)504 0.00 115q88 0.00000000
t1:I 27('.01)0 0.~07b2"I J 0.U1'91C1~4. 0.0107547q 0.01134142 0.00Hl1l21 0.011000000
I 212.500 0.I)05'~7517 O.1)046q]l)1) 0.01l5i!7f1b) 0.0011301')2 0.0021509b 0.000US511
(J'\ J\!>.n"~ 1.01 ]6n'l2 0.00611521'8 0.0~1I81\1J5' 0.00561011 0.00111)25 o.IIOOOoono
 IH.50') O.~lqlc:.}n9 0.1I16f!]!l42 11.1)00811]96 0.00Z150Qo 0.000195511 0.00000000
    SEASON I   
   STA9IlITY CATEGORY 6  
   H",D SPEED ilII'ID SPEED IIINO SItEED WIND SPEED "IND SPEED III~D "[£0
I I  cn~Ii""Y I C&TEGORY l C"EGO",'] CATEGORY II C"!GORY!i CATEGORY 6
","ftUQ'J ( Q.7500~PSJ( 2.5~00~PSJ( 0.3000MP5)( 0.8000~PS'( '.!000HPS)(Il.5000MPS)
(Of.I>~tES)        
~.OOO  r'.I)C7(1]Q'50 O.OlqoHOI) 0.00tJ1I8n 0.110000000 0.00000000 0.00000000
.!.?5(10  0.')2I1n51) 1).0?012102 0.110 191j'5Ql 0.00000000 0.00000000 0.00000000
''5.0011  0.01271021 0.00)]ZII21 0.0007'1217 0.00000000 0.0001/f5511 0.1101100000
"7.5<'0  l'.iJfl3711j?9 0.OCIIHZ5 U.000~'I108 0.000)'1108 0.00000000 0.00000000
9('. on')  o. '),) 7<,26 13 0.000"7771 O.OOOHIOII 0.000}/f108 0.00000000 0.00000000
 IIZ.5,O  1I.')ra}12~fo7 0.00312867 0.01)150033 O. 000/f1771 O.OCOOOOOO 0.00000000
 1)'5.000  0.""11311'12 o.0001063P 0.00008n 0.00019108 0.00000000 ~.OOOOOOOO
 1'51.'50~  fI."JZ'1HI1 0.~01l7325 0.IIOJ)!\87Q O. 000/f1771 0.0011195511 0.00000000
 I~'. 00'1  0.n'lZ9Ht3 0.IIU8?1?75 0.00<)(101)25 0.001 Jolin 0.000195'50 0.011000000
 ?ri.'S"O  o.Cn'>Pjl'l'H. 0.11°025730 0.00b:!57J0 0.00I3b879 (I.OOU~OOOO 0.00000000
 ns.~rall  ,).~n.!!o1l650 0.00:\'51975 0.OOHI08) 0.ilOIl13.!5 0.~00U'j54 0.0001.100110
 ~u7.5"(1  ',.,1I1Z5112}0 a.~l)qllqho 0.00527/f/)3 O. 00i'!73 758 0.00000000 0.00000001)
 770.1100  1).10001)\ 7f1 0.0I)Q}"6UO 0.01173250 0.005U96) 0.00117325 0.000001100
 2'11.. 1Ij".)  iI.,'''195'512 u.00~""85. 0.0~&0,,119 0.002150Q6 0.0001/f5'511 0.00000000
 J' ';. 0.1')  (I.'-'~312.!l7 0.0061143"" O.~04Jol'fl O. 00H242 I 0.0011"7771 0.0001"'5511
 }H.!lIIO  0.1I1'J161J11 <'.0'1°2""4 II.U07b2"tJ 0.f)0175'i88 0.01l0586b] 0.00019S511

-------
"OOH'I".I.ST,o
Table B-1.
I'.JA~.I'S' 101~'
'80' ,
.... 15CLI .............
~o~,1 "I"' with Plu~, RI.,. St8ck R,I,..,. ("ODElSP.IOR)
- IIClT INPUT DATA (CONT.> -
.."..., PAGE
, ...,
ITABILlh
ITA8TLITY
1T881L'TV
'''!IlL ITY
IUblLITY
IU"ILt"
t,;j
I
-...J
ITA81LITy
1"81LJff
ITABllIrY
I"BIlI TY
IT "'Ill "
STAblLlTf
CnEGIIRY
C.rEGM',
C'TEr."~y
CITEGI'PY
CHEGJq.,.
C .,EG,)RY
C. fE(:.,...,.
C,TEG"'IY
r A fEr-CllfY
C-'EGD'"
C,TEr.('Ii!y
C,IEf.l,I'y
- VERTICAL POTEHTIAL TEKPERATUR[ GRAOI["T (OEGR~£a KELVIN/NET[R) -

~1~jO SPEEu wlNU SPEED WI~O SPEED WIN~ S'EE~ wIND SPEED wIND IPE[O
CATEGO~Y 1 CATEGORY l CAT[GORy] CATEGORy 4 CATEGORY 5 CATEGORY b
10.nO~OnOE+n~o.nooooo£+00n.0~OOOOE+000.000oooE+OOO.00oOOOE+OOO.OOOOOO£+OO
iO.OO~~oo£+ooo.nnOOOoE+OOO.OoooooE+ooo.noooooE+ooo.ooo000£+000.000000£+00
]n.o01~OQE.oon.oonOOOE+0~n.On~000E+000.?000ooE+000.000OOOE+OOO.OOOOOOE+OO
Qo.uUQOO~E+of'o.nonOO?E.OOo.~ooonoEtooo.ooooooE+ooo.ooOOOOE+O?O.OOOOOO£+OO
~0.Znnoou£-nln.100000E-OI0.1000ooE-nI0.ZonoOO[-010.IOOOOOE-OIO.lOOOOOE-OI
~n.3500noF..01".]5nOOOE-010.]50000E-010.]50000[-010.]'0000E-010.]50000E-01
. ~I~D PRnFILE POWER LAM [KPONENTI .

~INO SPEED ~INO SPEED wINO SPEED MIND aPEEn WIND "[[0 WIND IPEED
C'TE~ogy 1 CATEGORy I CATEGOHy] CATEGORy 4 CATEGORy 5 CATEGORY b
In.I'loonOE+~oo.r.OOOOG£+ooo.oooonoE+ooo.oooono[+ooo.ooOOOOE+OOO.OOOOOO[+OO
In.15000rE.noo.noooooE+oOO.00000oE+000.OQOOooE+000.000OOO[+OOO.OOOOOOE+OO
30.?nOJon[.ooo.nooo~o£.nou.onooooE+000.oonnnoE+00o.000OOO£+OOO.OOOOOOE+OO
4n.l50000E.ouo.QonoOOE+unn.oononnE+onn.00noooE+000.000OOOE+OOO.OOOOOOE+OO
5~.!~oonoE.ooo.~~~00uE+nQo.n~nonoE+ooo.000000E+ooo.000OOOE+OOO.OOOOOO£+OO
bO.J~~nooF.+o~n.nOOOOOE+OOO.QoooooE+ooo.oooonn[+OOn.ononOOE+ooO.OOOOOOE+OO

-------
"O!)ELS".L~T,II
15-JAN-198S 10ioT
HOd.' ..t". ~tth P'U~' At.., 8t.c~ -""'" (MnDELSP.80RJ
- SOURCE tNPUT DATA -
-.-.-.-.-.-.-.--....---..--.-..----------.....-.---.-.-.----....-....-.......--.-...-.-.-.......................................
X ST-eK -2~.OQ -10b.00 1.00 0.00 GAS Ext' TEMP (OEG K)' i8b.83, GA8 ExtT VEL. (~/SEC)' 1..20,
STACK DIA~ETER (H)' 1.510, HEIGHT 0' ASSO. BLDG. (H). 0.00, WIDTH 0'
ASSO. ALDr.. (H). 0.00, WAKE EFfECTS fLAG. 0
- SouRCE STRENGTHS (CURIE8 , YEAA , 8Q "ETER
SEASON I SEASON i SEASON 3
2.201l00E+03
200.00, 180.00 18 LE88 THAN PEAMITTEO
ino.llo, i02.50 IS LESS THAN PEAMITTED
GAS E-IT TEHP (DEG K)' Z8b.83, GAS ExIT VEL. (H/SEC)' 1'.20,
STACK DIAHETFR (M). 1.510, HEIGHT OF ASSO. BLDG. (M). 0.00, WIDTH 0'
AS50. BL~G. (M). 0.00, WAKE EFfECTS FLAG. 0
- SOURCE 8TAENGTHS (CUNIES , 'E~R I sa HETEA
SEASON 1 SEASON 2 SEASON J
Z.2(\000E+03
0.110 GAS EXIT TE~P (OEG K)' Z8b.~3, 8A8 E'IT VEL. (N'SEC). 1'.20,
STACK OtAHET~A (~). 1.510, HEIGHT nf AS80. BLOG. (N). 0.00, WIDTH 0'
ASSO. BLOr.. (~). 0.00, MAKE EfFECTS FLAG. 0
- SO-JACE STRENGTHS (CURIES I YEAI( I 88 "ETER
~EASO~ I SEASON 2 SEA8DN J
i.20000E+03
X,V. 500.00, 337.~0 IS LESS THAN PERMITTED
0.00 GAl EXIT TEHP (DEG K)' 28..83, GAS ExIT VEL. (H/SEC)' 'b.20,
STACK DIAHETER (~). 1.510. HEIGHT OF ASSO. BLDG. (H). 0.00, WIDTH 0'
AS'O. ~LOG. (H). 0.00, WAKE EffECTS FLAG' 0
. SOURCE STRENGTHS (CURIES' YEAR I sa HETER
SEASON I SEASO~ 2 SEASON J
2.iOOOOEt03
0.00 GAS EXIT TE~" (DEG K)' 2~'.83, GA8 ExIT VEL. (M/SEC)' '6.20,
STACK DIAMETER (M)' 1.510, HEIGHT Of ASSO. BL~G. (M)' 0.00, ~IDTH 0'
1550. BLDG. (M). 11.00, NAKE EFFECTS fLAG. 0
- SOYRCE STRE~GTHS (CURIEl I YEAR' 10 METER
SEASON I SEASDH i SEA80N 3
2.20000E+03
..., I~CLT .,...",.....
C T SOURcE SOURCE
A & l~d':l'E R TYPE
" ,.
o t
1
C::JOIWl~UE
(:' )
EHISSION
I4EIGHT
(tI)
Y
COOF<~INATE
(")
Table B-l.
It.ae b
........ PAGE
6 ....
B&Sf: I
ELEV- I
AT tON'
(k) ,
. SOURCE DETAILS DEPENDING DN TYPE.
) .
SUSON II
.A"NI~G - DISTA~CE PET~FE~ SOURCE
MAR~I~G - ~IST_~CE HET~~(~ 50U~CE
X 2 STACK 322.00
1 AND POINT X,Y'
I ANn POI~T x".
184.00 1.110 0.00
 x ] SUC~ -~!l2.00 abO.OO 1.00
t,;1      
I      
00      
 IIARNII.G . DTSU'ICE tiE T ,IEf" SO',RCE ] ANI' "OINT
 X " STAr." '5~J.uo -1100.00 1.00
I
5
suer
-11'1.00
1.00
-1195.00
) .
1(l80N II
) .
8(180'" II
) .
IUION II
) .
IUION II

-------
Table B-1.
140:>ELSD.L1IT,a
15-JAN-19'5 loi07
!'.g. 7
..
,;ItIUAL GilOUfiD LEVEL CONCENTPHIOII
(PICO CUAI!S I LIT!~
- GAID SYSTE~ RECEPTOAS -
. x AXIS (RANGE , "ETE~S) -
1000.000 21'00.000 3000.000
CONCENTRATION
  ........ !'AGE 1 ....
) 'AOM ALL SOUACES COM81NED ..
11000.000 5000.000 1000.000 8000.000
.... lseLT A'."".'.."
~od.l "I~. with Plu~. AI.., St.ck Ael..... (MDDEL8P.80R)
2~0.ono 500.000
, '.13 (AlI~:UT" &E&RJ;lG, UEG~EES )
.-.-.---------.-.--------------.------.-.-.-.---...-.---------------.-.-.-.-----.....-...-.-........-...............
 337.'5011 0.ll!!8!!7 0.1]0881 0.133513  0.09"'9  0.061367 0.051S01 O. OI05U 0.021600 O. on..,
 31'5.0(10 0.17'1911 0.10117110 0.103Q67  0.0902U  O. 01&!71b 0.058008 0.0111112 0.033108 0.0181"
 ,!1c?~00 0.IS017''' 0.0909H 0.0/13900  0.08511111  0.0681102 0.0536114 0.OQ3055 O. 0Z96'! 0.02'1158
 '7'1.ll('0 0.1~3t>lO 0.1'81'410 0.011067  'I.OllII1'1I2  0.0182111 0.06113"5 0.055956 0.0110980 0.015'"
 Z,'7 .~UO O.I~b'>IIZ O.l'St1bU l).o7bUO  0.1)7'9010  0.067011 0.0531"9 0.0113557 O. 03029J o.ontlJ
 uo;.Ol'O ". 1 '5.'~lIa 11.0941111 0.08'5329  0.098163  0.091lSQ 0.01151&! 0.065H5 0.001921 0.0111'0
 ,ol.'}oO 1).111;23 O. J:ll5119 0.118P22  0.lb6!1ZQ  11.16011511 0.1S7I112 0.115143 O. 08ll''1J 0.0111088
 I 11(\. Ol'O 0.1111",)0 0.1i!1IQ19 0.211'87  0.19\138  0.1170Jb 0.112912 0.089239 0.060501 O.OSU"
 1'57.'5!!/) I'.,"IIHO 0.l"P/)111 11.213'520  o.,JQ,Jo  II. U1481 O.IIIlIOU 0.119181 0.0826911 0.010111
 13'5.0;.111 ('.l9b3(,~ 0.27'5135 0.J571»'5J  0.19156"  0.135090 0.100510 0.018122 0.052003 O.OI)UI
 I tl.500 n. n~'IIO I). HOt>'iO n.3U59"  0.1803711  0.109'"] 0.0753116 0.0560611 0.0)5518 o. OZ958Z
 91'.1)00 a. :\ /I l' 71 t 0.31'725:) 0.2":nn  0 . 19/)41 19  0.139'53 0.10'5105 0.082518 0.055927 0.01"80
 b1.500 ~.l!l5175 0.315351 0.298232  0.10~9h  0.093l8b 0.0611717 0.050'" 0.O)U,6 o.OZUJ7
 115.000 1'1.2111\"" 0.321093 0.1'52209  0.IZJ9b2  0.080135'5 0.058181 0.011'67 0.0l97OZ 0.025061
 ii'.50(l u.i'1H7Z 0.1411117 1).200158  0.IOQ399  0.095792 0.0119052 0.05l81J 0.0315911 o.onlOt
 0.0110 !'.'o1~)11 0.3l1)1I52 0.219195  0.14II0'b  0.1031119 0.017055 0.Ob01aa O.OQIOOO 0.0 )QUi!
b::I              
I              
\0     - G~ID SYSTE~ RECE!'TOAS - ,.   
     - X 'XIS (IUNGf: , HH[Rs) .    
  'lOOI'./lUO 100011.000 15000.000 20000.000  30000.000  50000.000   
, UI5 (&lJ."UT'I 8E&;;1 'jl;, HGMEES )   C(\NC!~TP.ATJO'I     
 ----....---.-.---.----------.-----.-.-.--.-..-.---.-.-...---..--.-.-........-.-............................-........
 317.500 (I."10H8 ".1)17805 0.011)599  0.oon91  O.OOIl]B 0.002hll   
 31'S. 1101'  0."~4I1~1) 0.02U61 0.013205  11.009180  0.005080 0.00'1111   
 i!°?SOIl 11./)21"'0; ".I'I'Z'b 0.1'11515  0.00192(1  0.00U96 0.00Z01l9   
 ,7'1.l'l)u U.0)13:'3 0.1I2H1I5 o.oun'  O. Oil 125  0.001)33 0.00]11118   
 Z/17.50(l 0.;J~21179 0.n1'i700 '1.011797  0.011'100  0.0011195 0.002095   
 Z1C:. no,} (1.,,)1»758 o.n);?II'Z O.OlOJ&"  0.010355  0.008133 0.004111\   
 i'1'Z.SOO 0.1)1)5315 0.0581111 0.03/)]115  0.0i!5UO  0.0151)2 0.008466   
 IlIr.ool' ).U~Ho3 ".I'IH809 1I.IIU'108  11.01573)  0.009281 0.00411i!1I   
 I r:; 7 . '5"0 ".uol~73 0.0511050 (I. oJi!a1Q  1I.021~.57  0.01336/) 0.001009   
 I)~.O)/) (I.O}7?59 0.031912 0.019253  (I.OIU It.  0.001109 0.00]995   
 I H.';',,, 0.1"5139 (1.021117 0.012317  0.0(8)05  0.(loaP56 0.002502   
 '11. O'JO ".0~1145 O.~3bO'58 0.01l'199  0.011181111  0.0081180 0.000118]   
 117.<;0(1 0.0')<)3) 11.'120615 O.OllUI  0.0('11270  0.00111171 '0.0025]1   
 115.1'00 II. 1)1 I '.itb 0.018n9 0.0111987  0.007504  0.00"20 0.002297   
 2;>.5,\1) o.('Z..olj' 11.021105 0.11121106  (I.00llb21!  0.01)5019 0.0026112   
 'I. OliO  1)."J1n70 0.0i'I)3Jt 0.0151131  0.010773  O.(lOblll) 0.OOnb9   

-------
INDUSTRIAL SOURCE COMPLEX LONG-TERM MODELING RESULTS FOR REFERENCE
UNDERGROUND URANIUM MINE, MODELED WITHOUT PLUME RISE
,J, Table B-2 )
B-lO

-------
Table B-2.
"oon,p.lST,]
1~.JA~.lq~5 10106
'.0. I
.... l!tlT .............
lIorl.1 "I~. wIth No Plu~. R'.., G~OU"d L.v.1 A~.. P.I..... (HODEl'P.80R)
........ 'AI;E
... -'~~IT~G . F~[~. OF ~CCURRE~CE ~F SPO VS. DIP 18 NOT 1.0 'OA SEASON
. ISClT I~PUT DATA.
I, PROG. DIVIDES 8y
~.IIQOO TO NORMALIZE
tP
I
.....
.....
~HI.IHln uF SOIJIICE3 8 ~
~:'I'IIIEI/ N' K AI IS r.r.ID SYSTlf1
1'1J"ilEI\ I'F Y .\1 IS G" 10 SvS TE"
"'1I~'E'Eq 1Ir: SP~.t"l. POlIITS 8
!11'!f<[F< or: S~ASO'!S 8 I
'11"'''[11 OF oIllIn !PEED CLASSES 8 6
hU"~ER OF ST~81l1Tv CLASSES 8 "
PIII"'..ER n, 41'ln "'1~f:CTI"U ClAS9ES 8 U
'Ill "'l'''6E'' !I' I'UA nLE USEn 'OR REPORTS 8
TilE FRr~r.A~ 15 RUN 14 ~URLl ~OOE
CO~CE"'T~'TIO'J (~EPOSITIOH) UNITS CONVERSION ,ACTDR 80.]17nQQQq[tOl
ACCElE~ATIO~ OF ~oAVITY (~ETEPS/SEC..Z) 8 Q.800
Hnr.HT OF :'[A~"HE"EHT :1F ~'PID SPEED (PIETERS) 8 7.000
P.r~'I':'ll'lT "AI:'''[T£II '"OR U"SHSlE COHnlTlo"8 8 0.61)0
t:"'''AI 1"If.'1T PA~"'ETEn FOR STAtilE CO"DITIO~S 8 0.600
CO~I!ECT'1" A~GL~ FDA ;~IO ~YSTE~ VEHSUS DIRECTION UATA NORTH (DEGREE8) 8 '0.000
OEtA1 COE"FltIE~T 8n.npOOOQOaE+1)0
pDr'GPLf, lIP' 10:~ ''''ITCHES 8 I. 1', I, n, 0, 3, l, l, 3, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,
ALL s'tI.'oICE!) H.£ JSlD T~ F(lR'1 SOLIRCE C('IHBI"ATlDH I
"A:.G!: J( 41.15 CHI!'! S'ST~'" "U1NTS (HETFIIS )8 lOO.OO,
5n~~.a~. 7~?0.OO. ~o~o.O~, 9000.00, 10000.00,
R~'FINR , '-13 G~I~ SYSTCM rOINTS (DEGR!ES)8 o.no,
13~.o~. 157.5', 18n.oo, lal.50, 2l5.00,
rOINTS 8
POI~JTS 8
o
15
III
1 ....
AZIMUTH
500.00, 1000.00, lOOO.OO, 3000.00, 4000.00,
15000.00, lOOOO.OO, 30000.00, 50000.00,
22.50, 4~.00, 67.50, QO.OO,
l07.50, l10.00, 192.S0, JI5.00,
112.50,
337.50,
SEUO"
. ~~~I!"T AI~ TEMPERATUAE (DECAEES KELVI~) .

STAbILITY STAIlILITv 8TABILITY 8TABILITY STAelllTY l'A"llITY
CATEG~RY 1 CATEcuqy l CATEGnAY 3 CATEGOAY 4 CATEGORY 5 CATEGOAy 6
,a~.~3no 28b.~300 28b.-JOO 286.8300 l8b.8300 l8".83~0
1"81LITY
IUblLtTf
'TABILllf
SUblLl ,.
STAf!ILIT'
SUDILlff
. ~I'I"'G LAYER HEI8HT (METERS) .

SEASON 1
~l~~ 'PEEO wI~n SPEED NINO SPEED MIND I'[ED WIND IPEED NINO I'EE~
CATEGnAy I CATEGJRy l C'TECORy] CATEGnAy Q CATECOAY 5 CAT~'ONY'
10.I~oaonE+000.1000nu~+oqo.loooooE+OQO.lnnoooE+04n.looOOO£+OoO.IOOOOOE+O'
2".lo~'nQE.04n.10nnoo[+ooO.lu~onI)E.000.IOOOooE+OQO.IOO000E+000.lnnOOO!+04
'r.luoaun~.nQ'.I~OO~OE+n10.I00001E+OQO.IOonOOE+n10.100OOO£+OOO.IOOOOOE+OO
~~.IJO~~~E+u~o.1uOOouE.ooO.lnoonoE+040.1000ooE+040.IOOooo!+nQo.lnOOOOE+04
50.loooonE.n50.ln~npOE+o50.luoonoE+OSo.100ooo[+nSo.1000~O[+050.IOOOOOE+05
bn.IGon~OE.o5o.lonCI;OE.n50.loOOOO[+05n.looonoEtO~0.IO0000E+050.100000E+n5
CATE;-:OPf
CA'Ec:"Qy
CtTlC:'Ii'v
C ~ '[(;i,lI"
C'TEr.,<:v
CHfr.r,r(

-------
MOOH '" .lST 13
15-J.N-I~~5 10106
Table B-2.
'101 Z
.... ISCLt .............
~o~.1 "t"1 with No Plu~1 Rill, Grou"d Llvlt .rll RII"..I (MOO!LAP.SOR)
- ISCLT INPUT DATA (CONT.) -
- FR('IUENCY OF OCCURRENCE OF NINO 8P[!0. OIRECTIn~ AND ST.RILITY -
susaN I
STABilITY CATEGORY I
   1IMII SPEED WINO SPEEO WINO SPEED NI~D SP!ED NINII IP!EO wINO .P!EO
   C HEGO!tY I caTlGORY 2 CATEGORY S CAT!GORY 4 CAT!GORY 5 CAHGORy.
 CJ"ECTIII', ( ~.7500~PS)( 2.5~OOHPS)( 4. 3000HP3) ( '.8000~PS)( 9.5000HPS)(12.5000MPS)
 (OE.iiIJEES)        
 11.001  O.O"Hql~d 0.0110001100 ~~OOOOOOOO 0.00000000 o.onOOOOIJO 0.0110(10000
 22.500  '.,}~,nCJIf)8 0.000001100 0.001100000 0.00000000 11.000000011 0.00000000
 45.0~0  O. '1f:1(\01l1J~I) 1).0('11100(100 0.00000000 0.000110000 0.1100000011 0.000011000
 117.51)0  ~.IJ"IIO'ln"o 0'.0001'1J1)00 0.01l0001J00 O.IJOOIIOOOO 11.00000000 0.00000000
 CI,).oflr  J .1)0,119554 0.000000011 0.00000000 /I.IJOOOOOOO 1).00000000 0.00000000
 112.50':'  ('. ""1)00000 (\.011011554 0.00001)000 O.IJOOOOOOO 0.111)1100000 11.00000000
 130;.00(1  ~.001/1~5')4 O~OOOOOOOO 0.00\)00110(\ 0.00000(100 0.1100000(\1) 0.0(1000000
 157.511(1  '1.01)0'5'311/,] 0.00000001) O.O~OO!)OOO 0.000001100 0.00~(l0000 0.00000000
 I.~ \J. en"  ~.f''',,~777t ~.0'l0]qI08 0.000(11)1)00 O. 'JOIIOOOOO O.~OllOOI)I)O O.IJIIOOOOOO
 2"2.5""  ,1."Oil78~ 17 11.001)78217 O.OOIJOOIIOO O.IJOOIIOOOO 0.00000000 0.0000(\000
 ?~5.0nr  I).Olln"ZI7 0.00097771 O.OOI)"nOoo O./lOOOOOOU 0.00000000 0.0/1000000
b:J Z07.50<'  J.I)"i!3~1I511 0.00U78217 0.000110000 /1.01)01)11000 o.nIlOOOOOO O.OOOOOOIJO
I Z7~.U{I"  ~.0"H"I08 1I.001]/lHIJ 0.0000i)1I00 0.1)01)00000 11.00(00001) 0.00000000
...... Z~2. 5,")  I}. )"')7IIZI7 0.1I01J1155'1 0.000001100 0.011000000 0.110000000 0.000011000
N ]1 ".O~"  1.(11'119550 0.110117325 1'.01)1)00000 U.I)O(\OOOOO 0.(10000(\00 0.011000000
 .D7 .~IJ'!  '1.,)nO')6b/>] ('I.~OI)\ 1SSQ 0.001/(10000 1).1100'100110 11.00000000 0.01)000000
      SE.Sntl t   
     STABILITY CATEGORY I  
nl"ECTln',
(C\EGFE! S)
I'. .JI, 0
i'l. 5t'~
,IS. r.r'(J
.,7.5"~
'ic.OO.'
112.'i~.'
I )5.II~IJ
I 'j 7.0;(,.'
1 P oJ.:ln",
:!02.S01
;>;>r;; .fIU',
;> "7.5'1"
/7:1.1)(1"
;>ul.5(1.,
31!'.C~iI
JH .5'1"
rit~o SPEED ~t~o 'P!ED ~I~O 'DEED NI~O SP[EO NINO SPEEII wINO IP!EO
CAnr,.)r.y I C.TECI)RY 1 CH!GORY J CATEGrJRT 4 CATEGORY ~ CATEGORY 6
( 0.7~'(I'!P')( l.5000~P$)( O.]I)(lOHPS)( 1I.8000"P5)( 9.5000"P5)(12.5000"P5)
0.0''{l1~108
1).0/)l,'5811/>]
0.')''')191\18
').Cn~I)IJO(l1l
I).,)c"oonOO
11."001"'5')4
".(I"(I'5~lIb3
'J. i)1I175""8
r.nlJl]1b50
~.J"1 J,>~7"
". ""')7"~17
:'. ai' 'I'H7H
'~.~"19777'
".(11'117)2'5
".'J':1I71
-------
"DOH.' .l Sf , J
Table B-2.
15-JA"-19~5 10~06
lI.a. 5
.... ISClf .....,.......
No~.1 ~I". with 110 Plu.. Rf.., O'Ou"~ L.v.' A,.. R.I..... (MODELAP.SOR)
- ISCLT IHPUT DATA (CO~T.) -
- FR".III~NCY 0' UCCURRENCE 0' WIND SPEED, DIRECTION AND STABILITY -
SEASI)N I
ST'BILITY caTEGORY 5
   011110 SPEE!! "1110 !lPEEO 111110 SPEED wl~D SPEED III NO SPEro IIINO 8PEED
   C"EG!)'!y I C&fEGl}qy l C"EGORY] caTEGORY II CATEGO~Y 5 c&TElfDRY 6
 D !,IE( TI O~. ( 0.13I)CHF'5)( 2. 500'I~PS J ( II. ]OOOMPSH 6.8000"P5)( 9.5000HP5)(I'-.5000H~S)
 (DFGI/EESJ        
 0.0011  0.00011155/1 0.01)2151106 o.OOlt73i!5 0.00000000 o.nooooooo 0.00000000
 ~2.5110  u.')uU5l'66J !).OOOJCIIOl' 0.000'955/1 0.00000000 0.00000000 0.00000000
 115.('''0  0.01100001''' 0.0",,91111 0.00000000 0.000110000 0.00000000 0.00000000
 t-7.5I)O  O. ')\11)1'15511 0.0001'J55/i 0.00000000 0.00000000 0.000110000 0.00000000
 9~. .'0"  0.1)"1)1115')4 0.0110'955/1 0.00000000 0.00000000 0.011000000 0.00000000
 Ill.'3O')  0.00078<'1' o. O(l01i1ll1 0.110000000 ".00000000 11.110000000 0.00000000
 U5. ~ro  0.1)"IIHi!5 0~onOJCI108 0.0000')000 0.0000001)0 0.00000000 0.000/)0000
 157.5"0  ".OOi!3II1I50 (I.01li!H650 0.000(101)00 0.00000000 0.00000000 0.011000000
 I~r.!'ol)  O.IIOIl1l91~1I 0.00]91"83 ;)~00n18211 0.00000000 0.00000000 0.00000000
 l'li!.>OIJ  '>.001115512 o.OO]HIli!1 0.1I0293JU O.ilOOOOOOO 0.00000000 /).00000000
 i!~5.r.OO  0.0"19551i! 0.O(l1159M 0.000711?11 1).0011195511 0.1100000(\0 0.110000000
 i!1I7.5(\0  0.ulln.,l'79 0.001955112 0.onll867 0.00059665 11.00000000 0.000000011
 .7U.000  II.I~0]}Z/l21 1J.00J715i!9 0.00i!]Q650 0.00078217 0.00000000 0.00000000
b;j 292.5011  0.0(\1561133 .).01)111011]8 1).000]9108 O.IIOOO!lOOO o.onOIlOOoO 0.00000000
I 
...... )I 0;.11"0  r.onI95511i! 0.00215096 0.00ZIS096 0.000(1(1000 0.000110000 11.00000000
v.> 317.50u  o.on'n~I"1! 0.,)OlI51)~b 0.OOIQ5!'IIZ 0.0001950;11 0.00000000 0.00000000
      SUSOI/ ,   
     STABILITY CATEGORY'  
III !'1ft TJ(J;~
(f'lE:iAHS)
C .0"0
U...tJ~
'IS.OOI)
b7.5CII
lIa.~\I"
112.5(10
1\5.'In'l
11;7.500
I ~l . ur"
1';?5n:1
z..«;.nllll
l"'.S""
i1e.ollo
ZQ~.'5'1~
310;.I'AlI
\37.5"'/
WI~D SPE!~ "IND 8PEED IIIND SPEED WINO SPErO I1I~D 8P[ED wl~D SP[!O
CI'E~O~Y 1 C'fEGQqy l CI'EGQRY 5 CAf!GDRY, CATEGORY 5 CAT£GO~Y 6
( U.75"n~PS)r 2.5uuO~PSJ( 1I.]O(lO~PS)( 6.8000"PS)( 9.5000~P8)(IZ.5000HP8)
0.00/119938 0.0066/11142 0.001955QZ 0.00059108 0.00000000 0.00000000
o.00~"~"5/i O.OUII1]i!5 0.0(\05"'''6] 0.000195511 0.00000000 0.00000000
11.011501511 0.0011 HZ'5 0.00/)'5~"5 0.00000000 0.00000000 0.0/)000000
0.{lI)/lIIQ1"f> U.OOOIlO"OII 0.1100001100 0.0')000000 0.00000000 0.00000000
1).(1')'1"'1139" 0.11001'1'554 0.00019S511 0.000(1)000 0.00000000 0.00000000
O.t)"~IIQ]OO 0.nlllh8H 0./)00J9108 0.000195511 0.000110/)00 0.00000000
1).II~oe4J'I6 0.OOZ9]}U 0.001'S611]} 0.000110000 0.00000000 0.00(0001)0
0.:''14109)0(1 II.OIl2157S111 0.0011 n25 0./)00195'54 0.00000000 0.00000000
'I. /):J51175 I 7  lI.n067'57311 n.1I01I~8850 11.0011'59"" 0.110000000 0.00000000
(1."1;" I 0113'" 0.0115tl071 0.l)nt:.05188 0.00011711 0.00019550 11.001100000
'.n(1-1a'7~f> 0.oo.na511 0.005117071 0.00HI5?9 0.00111125 n.oOOOOOOO
0.,"JI28b7 1).~0]51975 1).005117511 (1.(\011052/18 0.00058663 0.00000000
(I.oo'uot:.JS O.OIlU'HII. 0.O(l1f1Z61J 0./)0741058 0.110091111 0.00000000
11.1)"27]1'58 1I.004b1JOO 0.00521"f» 1).00)]Z4Z1 0.00059108 0.000000(\0
".11'1<;"'''''1.'5 0.01)]1152' 0.01l~o1511 0.002150'11 0.00000000 0.00000000
n.nl(')bHI 1).1I(l6~43'16 0.00su1511 0.000'11771 0.0001955/1 ".00000000
........ PAG[
) ....

-------
"OOELU' .lST 1:1
Ta,ble B-2.
15-JAN-l'l85 loi~~
'10. 0
.... 15CLT .............
Mod.1 ~I"e wIth No Plum. RI... Ground L,v,' Ar.. R.,..... (MODELAP.SOR)
- ISCLT INPUT O'TA (CONT.) -
O;j
I
......
~
DlIooecTl(1:1
cr.ElicEE S)
0.0110
l2.5PO
QS.n~o
.. 7. Sn\.
90.00Q
112.500
I3S.0nn
1';7.5011
I:p.ono
?n~.SO~
U5.COO
~o 7. S'II,'
Z1J.OO(,
7.H.SOn
3I5.0l'U
3H .5('p
, I
CT~ECTIOI.
(r~GgHS)
".:00
?;'.~Ol'
45.0~0
I>7.5'1P
1u.un~
IIZ.5:1~
,,~.C'O
10;7.5"1)
l!lu.O'1~
"0'..5nl)
77<;. v,),)
,~7 .5')n
Z7".r.~,
cO?50n
~ J '). "'11)
337.0;"0
- ~RE~UEHtY OF OCCURRENCE OF ~tND SPEED. OIRfCTION 'NO ST'SILITY -
SEASON I
STABILITY CATEGORY 5
 i'I HIli SPFEO WIND SPEED ojINII SPEED NINO "fED WIND SPEED wI"ID SPEED
 CaT~G(I~Y 1 lATEGCRY Z CHEGO~Y] CATfGORY II CATEGORY 5 CHEGORY ~
( n.7500~PS)( Z.5000"PS)( II.'OOO"PS)( ~.8000MPS)C 'l.5000~PS)(12.5000"PS)
 0.01115592'5 0.0100;59"5 0.00332021 0.00097771 0.00000000 0.00000000
 0.Ol857b1~ 0.001l1lbl79 0.00097771 0.000195511 0.00000000 0.00000000
 '.0125111,,7 0.002311~50 0.11('1(178217 0.0011195511 0.000001100 11.00000000
 f).01l11159~ 0.0~II71Z5 0.01)05~bbJ 0.00078211 0.(10000000 0.00000000
 0.\l150q310 0.0020;112(/11 0.0005!1bb] 0.00000000 0.1100000011 0.000000110
 lI.nn80u!lZ'l 0.001J1I970~ 0.01l2]Ob50 1I.001l5,bbJ 0.0000(1000 0.00000000
 1I.\llJeZI7.15 0.(lP58bbZ') 0.0013b879 0.000l'l55O 0.000I'l5511 0.00000000
 n.nn7!l21)13 0.003910Ft] 0.00136579 0.COO]9108 0.POOI95511 0.00000000
 0.G07!l21113 0.(106'JS?88 0.01l'i1l8008 0.00273758 0.011019550 0.00000000
 0.UnnI5Z" o'.on7(121,,7 0.90711]05" o.ooooHU 0.1100711217 0.00000000
 l).01l5'1AlliI" O.00.:jQIIh2"tJ O. Oil? 19oQ6 0.010751/7. 1).01lJ4laz 0.00332421 0.00000000
 ~.O"51/75!7 0.004,,'l]00 0.G051796] 0.0011](11'2 0.1I02150'l1l 0.00019554
 1I.1I'11>~7q2 0.0111,45288 0.001l88(1S11 0.0051>7071 0.1111117325 0.110000000
 0.01'1110109 0.0100HQZ 0.006(14]91> 0.OOZI50'Jb 0.000I'l5511 0.00000000
    SEUON I   
   STA~ILITY CITEGOAY .  
 :~11l1' SPHD "'I"':> SP(I':D WIHO SPEED WIND SPEED NI"'D SPfED WIND SPEED
 CUfGOFlY 1 CarFG(I~Y 2 CATEGORY] C4 'EGORY. CATEGORY 5 CATEGOlfY b
( n.75~~~~S)( 2.50CU~PS)C 4.]000"PS)( 1>.800ll~PS)C 9.5000~PS)(ll.5000MPS)
 0.00701'l511 :1.1111101900 0~0IlU6"19 0.00000000 0.00000000 0.00000000
 o. O? 1705 \J U.l)zr.72742 0.001Cl554Z 0.00000000 0.001)011000 0.00000000
 0.1)12111121 0.00H21121 0.nO;)78211 0.'>001)0000 0.000195511 0.00000000
 'J.(j('}715Z" (1.1)0' 1 7)25 0.O(l~391011 0.000]9108 0.000000\10 0.00000000
 ','. Ou ''''/0 \J ,'.;)01l~7171 0.0003"108 11.00039108 0.(10000000 0.1111000000
 n.0!)}Il'.!,,7 0.003IZ@07 0.0I)I5bll]] 0.001197711 0.00000000 0.00000000
 II.O~HOl9Z I).004UbJII 0.0013/0879 11.000)9108 0.11001100011 0.00000000
 o.onZ'lHt] 0.00117325 0.110\31>"19 0.00097771 0.000I'l5511 0.00000000
 1).)(IZ"3\1J ('.O\lAZIl75 \I.0058bIl2"! 0.00131>87. 0.110019554 0.00000000
 ".(I~llC;:l911 0.00"Z5114 0.'101>;>57]4 ".00131187'l 0.00000000 0."0000000
 n .".."J 1bSO 0.1)03'5197S 0.1)"]9108] 0.001l7J2~ 1I.1'001'l550 11.011000000
 ,).OOJlfjl/l!no 1).\louOH;,!> 1).005?7C1~] 1).00273758 0.00000000 0.00000000
 II. ~'ICI'o 11~ c.,)nQ1/t!>"" 0.111 I 73Z!lO  O. OI!5Z?'b] 0.00117325 0.000001)00
 O. .1019554;> O. I) 0 4'''''''i* 0.1)0601>179 0.001150.. 0."00195511 0.00000000
 ('.~,,312!1,,7 O.O'lIl"HClCI :1.(111030192 O. OllJ3ZII1I 0.011097711 0.000195'511
 0.01016'.117 0.0It02'.100 O.007blb1J 0.001759\18 0.00058116) 0.000195511
........ PAGE
II ....

-------
MOOEL" .LST, 3
T~ble B-2.
15-JAN-I'S~ loio.
-.08 ~
Hodel ~'~e w't~ No Plu~. Rt.., Cpou"d L.,.I Ap.. R.I...i. ("ODELAP.SOR)
.... ISClf .............
- ISCLT INPUT DATA (CaNT.) -
ITUIL ITY
.UBILlh
Sh8lLl TY
"AI!ILlfr
STAhlLITY
STA&IL 1 TY
'''8tL I TY
nUlL I TV
STABILITY
STABILlfY
nUlLifY
STltlLJTY
b:'
I
......
U1
C tTlG"IfY
C 4 fEGI"'"
CHEGORY
CaTEr.~w,.
CHEr.')~Y
C ~ 1E>;l"y
CaTEG.IPy
C"~G~qy
C "EGOtH
CHEGOPY
ClrEG.)"Y
C, 'EGI'ICY
. VERTICAL POTE'ITIAL TE~PERATUAE GRADIENT (DEGREES KELVI~/"ETER) .

~IHO SPEED "IHO SPEEO NINO SPEED NINO SPEED NINO SPEEP NINO SPEED
CATEGORy I CATEGORY 2 CATEGORy J CATEGORy Q CATEGOPY 5 CATEGORY ~
10.~u~~nOEtnOO.0~0000Etnno.o~0000E.oon.000000E+OOO.000OOOE+OOO~OOOOOOE+OO
lO.~0~OOOEt~no.onOOOOEtO~n.000~ooE.00n.000900E+00n.oooOOO£tOOO.OOOOOOEtOO
30.n~0000E.~Qn.0000~OE.noo.000onOEtOoo.000000E+00n.000OOOF.+OOO.OOOOOOEtOO
Qo.o~~~onEto~o.oonOOOE'O~O.OoooooEtnoo.oooO~OEtooo.nOoOOOE+OOO.OOOOOOEtOO
5'.lQO~~QE-ntn.~nn~onE.nln.2000~oE-010.20000GE-0IO.200000E-010.200000£-01
~1.35~~?1E-0In.350JOOE-010.3S00r.OE-010.3S00noE-010.3~0000E-010.350000E-01
- ~INO PROFILE POMER LAN EXPONENTS -

~1~O SPEEn WiNO SPEEO "INO SPEED NI~D SPEED NINO SPEED NINO SPEED
CafEGeRY I CATEGORY 2 CATEGORy J CATEGORy q CATEGOqy 5 CATEGORY 6
In.tonnoo[tooo.~oonOOE,oOO.OOOOOOEtOoo.ooonnoEtOoo.onoOOOEtOOO.OOOOOOEtOO
lO.'5n1~o[+nOO.IIOOOOOE.~on.OQ0009£tnor.000000E+00n.onoOOO£tOoo.onoOOOE+OO
3n.iUt'or~Etoon.nronOOE.n~0.onooonEtooo.000000EtOOo.00OOOOEtOOO.OOOOOOEtOO
Qn.2~nnOPf+OI'0.nunO?OE+OOO.000oooE+ooo.oonoOU£tOOO.~~OOOOEtOOO.OOOOOO£tOO
~1.3.IQoor£to~?nOOOOo£."00.~"nOOO(tooo.000000r+000.noOOOO£tooo.OOOOOOE+OO
,0.\Q?OO~E.C.,o.o~~~rOEtO"0.OJnOOO£'000.000000E+OOO.OOOOOO[tOOO.OOOOOO£tOO
........ PAGe:
s ....

-------
Table B-2.
IIODH:,p.I.ST, 3
15-JA"-198S loio,
"'~' ,
.... I~CLT .............
"od.1 "In. wlt~ No plu., Rt." Gpou"d L.v,1 Ap,. R'I',... ("ODELAp.SOR)
........ pA,r;
6 ....
- SOURCr; INPUT DATA -
C , S\I!JI(I:[ SIIUJ\CE
A A N!J"~' f> TYPE
" "
o E
II
coo,W' "ATE
('I)
y
COOI1I' I'll, TE
(IA)
E"'ISSION
HEIGHT
(:1)
BASE I
ELEV- I
ATION I
(H) I
- SOURCE DETAILS DEPENDING ON TYPE -
-----.----...............-..-.--...--.--..--.-....-.-...-.-.---.-.......-.-.....-..........-...........-........................
   ARE' -ill.(lO -1011.00 1.00 0.00 IIIOTH 0' AREA (H). 1.51    
         - SOURCE STRENGTHS (CURIES I YUR I SQ HETERPER SQUARE NETER) -
          SEASON 1 SE ASON 2 SE UON J SEASON 4 
          9.'"900E+02     
 ""WI"G - 1I15fA"'=E liE T ~EEI'I SOU'''E I AND POINT !C,Y' 200.00. 180.00 IS LESS THAN PEMM ITTEO   
 WAIW I',r. - t'(&TA~,CF.. RH"HII SO'JIfCE I AND POHIT !C,Y' 100.00. 202.50 IS LESS THAN PERIIUTEO   
 . l A;lO 12Z. 01) (8Q.O~ 1.00 C!.OO WiDTH 0' ARE' (~). 1.51    
         - SOURCE STRENGTHS (CURIES I YEAR I SO "ETERpE" SQUARE METEII) -
          SEASON ( SEASON 2 SEASON J SUSON 4 
          9.611900E+02     
 )( ) HEA .2,'2.1)0 111>1).00 1.00 0.00 IoII0TH 0' AREA (M). 1.'51    
         - SOURCE STRENGTHS (CURIES I YEAR I SQ METER'!" SQUARE M!TER) .
          SEASON 1 SEASON 2 SEASON 3 SE &SON 4 
          9.611900E+02     
 "'RIU"!; - lJl'Ur;CI:: BE ''''t:Eo, SOURCE ) AND POINT II,Y' '50/1.00. 337.50 IS LESS THAN PERl'll TrEO   
tI:I . II AilEA 5113~00 -11110.011 1.00 0.00 ~IOTH U' AREA (H). 1.'51    
,         - SOURr.E STRENGTHS (CURIES I YE'R I SQ NETERP!R SQUARE M!TEA) -
.....          SE &SON 1 SEASON 2 SEASON ) I[ASON II 
C\          9.64900(+02     
 I 5 ARF.A -110.nO -695.110 t.OO 0/00 IIIOTH 0' AREA ("I)- 1.'51    
         - ~OURC( STAEN;THS (CURiri I TUR I 8. "UU'U "U'Rt NrTU) -
          SU SON 1 SUSON I SUSON 3 1["0" . 
          '.64900E+1Il     

-------
Table B-2.
.cDDEL-p.LST,]
15-J_N-I"85 10.06
"01 ,
.... IStl' .............
Modll ~1"e ~Ith No Plu~1 Rt.., Gpound LevI' Apil RI'II..I ("ODELAP.SO~'
........ PAG!
7 ....
..
'~I"UAL 1ot1()UNO LEYEL CONCEI,TAATtON
(PICD CU~I!8 I LITER
. GHID SY8TE~ RECEPTORS -
- X AXIS (AANGE , HETEAS' -
1000.000 2000.000 3000.000
CONCENTRATION
, 'ROM ALL SOURCES COMBINED
..
lao.ooo 5po.n~0
, hIS PZI '11TH BE'~l.I", OF.GIIEES )
11000.000
5000.000
7000.000
8000.000
------......----.--------------.-.---..--...------.-..-----..---.-.-.....-.................................-........
 137.5r10 1I.I(If~9110 1.38a;!]" 1.1"3301  0.29]Q82  O.IUZ911 0.0911410 0.066836 O.OJ9911 o.on".
 3I!i.Oi/O ...3.140] ..1>1:7230 1.05351111  0.]\11119]  O. \11018 0.1111153 0.0811J16 0.0490OJ 0.040JJI
 Z"?!iOo ..01!501>3 3.1130173 1.03"009  0.322906  0.16Q02' 0.103891 0.0131155 0.041796 o.onn]
 ;'11). r.l:n ..0'110'/1 2."St897 1.007273  0.36361111  0.212052 0.\112590 0.IOa'i51 0.06119]' 0.053nl
 ZH.5(.1I R.'Ho;'5l11 3.09?]a,? 1.11170.  0.H.791>  I). \11911 311 0.1161117 0.01l\2Z2 0.0071190 O.03Ueo
 ~i'I\.OIl" 11.;j~9~~1> 3.1771~2 1.'H,21115  0.5211131  0.283071 II. \ll1I6~ I 0.132905 0.080905 0.0...0]
 ltoi.5"O 3."15293 7.5790.5 0.315895  0.9533'2  0.119506/1 0.3207"7 0.23107" 0.111\280 0 . II U"
 11'(\.0011 \.";>~1I50 6.01190"0 11.117632.  0.8371164  0.379105 0.228130 O. \56983 0.090978 0.0136"
 11\7. '5\'0 13. 7"~1.:a5 5."336911 3.12.1162  0.83111125  0.000671 0.282387 0.201320 0.IU356 O. nun
 11<'.0(10 I ~. 559'5GB 7. N.0907 11.1111537  0.600]32  0.2116087 0.1760111 0.1l26118 0.072078 0.0585"
 II ~. 51'0 1'}.9S"IZ1 11.1111001111 2 .111.119.  0.1153111/1  0.2031167 0 .120'l1l] 0.01l1l'0 0.0117105 o.onOo.
 )".".,,, 1 O.051"J6 5.<)92161> 1.]90!!Z8  0.011555  n.21>0710 0.1713\3 O. U]'l)4 0.075891 0.06ZS61
 I>1...JO o.lI~ill(\" 12. I 29735 I.H\3'!3  0.]3q,,56  O. \10]1111 O. t 065/10 0.071789 0.O/102Z9 0.OJ605)
 115.tI~0 1..,q'l~u 7.08119~3 1.1I'l1l015  0.293956  0.18;0909 0.095511 0.067'501 0.040219 O.UU"
 l:". !,.;('t 7.H1~11 II. ~q051J:1 1.113168  0.)2113Z9  0.I.b3U 0.10&651 0.0151142 0.011502' O. OJU07
b:I :I.ono 7.21"01 ..32111.11 1.1732~'5  0.3""635  0.195192 0.12.11" 0.09077. 0.055165 0.01l5U6
I                
.....             ','   
-...J       - GRID SYSTf" RECfPTDR8 -  "   
       - . AXIS (AANG! , MF.T[AS) .    
   'nllo.ooo 100011.000 1'5000.000 200111\.000  30000.000  50000.000   
, AX15 (A2'I"UT" Iill~J.lr;, n[r.AEES )   CO"UIITRUION     
 ........--..--.-......----------------------------.-..--------_.~--._.-_.--.----....--.-......_.....................
 3P. ~IIO 0.1)~1]\II 0."21315 0.0128110  0.'108510  0.00l1li70 0.002412   
 11 c;. r..:11 ~. .,1JObl> ".'}2'l137 0.0162118  0.010~1I1I  0.0010220 0.0031&0   
 l~? C;"" I). "2'194 7 0."2'5'562 11.0111'1115  0.00'l2'l3  0.005Z98 0.002.17   
 l7".J',O "."'1~1I35 o.l~nl/". 0.0220'11  0.01/11117  0.0011513 0.00113'111   
 11l7.!i(\() C.I) Ill!,.,q (I."21Z~2 0.0 IIIH7  11.009711  0.00511911 0.00271>0   
 ZZ':I. ')"" 0."5t>1}(I 0.1)1111171 I/.O~I>!I,,(I  0.0111035  0.011/1105 11.0115331   
 1'1;. C;"O 0.0""113 0.II/:I1M'1I 0.OQ1~"0  0.031.109  O.(lU.U 0.1)091>26   
 I "f'. "'.If' 1>.1t>IH9 "."52n. 0.(1282/111  O.I)I'Ietll  11.0105111 0.00531111   
 , -:' .., 'J" ~.~,~\5~1 0."'1520 0."]9..6  0.0"1>3.9  0.015115 11.007083   
 13'5. n ;(' p.I/II,,!!1I1 0.'Ulb1l9 0.11221>82  11.01119110  0.0'111500 0.00112"1   
 II,). "':0 11.011501> 0.'IZ01l16 0.(1111311  0.009378  0.005302 0.01121170   
 .~ " . ~} ':' t' ., .','P117 1).01l5}IJ 1).11253116  0.1\170]0  0.0091158 0.0050.7   
 01.!i'u 11."\"1115 0.11<'57"11 1I.'Hllni!  0.0093116  0.0053/11 O.OOZ7U   
 0'>."111 1\.IIUa'J3 11."23111>3 0.0Il~~9  0.0085"0  0.0011875 0.002117n   
 /;). Ij -: 0 II." };JIj ~O 0."ZII3111 0.1110511  0.1\096118  0.0'15527 0.00211\3   
 .\ . C ."1 ;'."3'170; o. II ~c!73J 0.~1"21111  0.01221)11  0.00701111 0.003111 I   

-------
I
INDUSTRIAL SOURCE COMPLEX LONG-TERM MODELING RESULTS FOR CASE STUDY
UNDERGROUND URANIUM MINES (MINE 11), MODELED WITH ACTUAL VENT ORIENTATION
. (Table B-3)
B-l8

-------
Table B-3.
.... uel'
.............
"I~e II Ntth VertIc.' end Hortront.1 Vente
........ PAG!
3 ....
- SOURCE INPIIT DATA -
C T ''IURCE
A A "IJ"Rf A
II ,
D [
SOURCE
UPIO
II
COIJI1DIIljATE
(., )
T
CClOIIOIta TE
(11)
E"USION
HEIGHT
(..)
tlA!!E I
El.EV- I
HION I
(M) I
- SOURCE DETAILI DEPENDING ON TyPE -
 ......-.------.---.-.---.----.---------------------.-.-.-----.-.-.-....-....-.-.-.-.-.----.............-..-...........-.-.......
 I  SHO -20.00 -130.00 1.00 0.00 r.AS EXI' TEN' (DEG K). 284.20, GAS EXIT VEL. (M/SECh 11.70, 
        STAC~ oIA"ET[A (H). 3.000, HEIGHT OF ASSO. BLDG. (14). 0.00, WIDTH 0'
        USO. BLDG. (14). 11.00, WAKE EFFECTS FLAG. 0   
        - SOUPCE ITRE"GTHS ( CURIES PER YUR   ) -
         SEASON 1 SUION 2 SEAsnN 3 IE UON 4 
         2.42000[+02 2.112000[+02   
 "AII'-ING -  1)15,,:.CE !IE' "'EEI4 SOI/RCE I AND POINT X,Y. 200.00, 180.00 IS LESI THAN PEAMITTED   
 tlAII,; I NG -  DI~H"CE "ET'"EEII SOURCE 1 UH'I POINT .c,T. 200.00, 202.50 IS LESS THAN PERMITTED   
 I 2 STaCK no.of' -1110.00 I.O\! 0.00 GAS EIIT TEMP (OEG K). 284.20, GAS ExiT vEL. (H'SEC). 9.10, 
        STACK OIAI4ETFR (M). 3.000, HEIGHT 0' AS80. BLDG. (M). 0.00, IItOTM 0'
        4550. "LOG. (14). 0.00, tlAKE EFFECTI FLAG. 0   
        - SDUNCE STRENGTHS ( CVRIEI PER YUR   ) -
         !lEAS ON 1 SUSON 2 SEASON 3 IUION 0 
         2.4T00IIE+02 2.47000E+02   
 . 3 5TAC" -2/10.00 210.00 1.00 0.00 GAS EXIT TEMP (OEG K). 2~4.20, GAS EXIT ~EL. ("IIEC). 10.00, 
        STACK oIAHETfR (~). ].000, HEIGHT OF ASIO. BLDG. (IIh 0.00, IIIOTH 0'
        45ao. BLDG. (M). 0.00, MAKE E'FECTS FLAG. 0   
b:I        - SOURCE 8TQENGTflS ( CURlfS PER YUR   ) -
I         SEUON 1 IUSON 2 SUSON J IUSON. 
-         5.115000E+02 5.115000[+02   
\D . 4 SHCk -20.00 -3110.110 1.00 0.00 GAS EIIT TEMP (OEG k). 2~0.20, CAS EIIT VE~. (H/SEC). JZ.OO, 
        STaCk OIAHETE~ (K). 3.500, HEIGHT OF ASSO. BLDG. (Mh -0.00, "10TH 0'
        ASSO. BLDG. (II,. ".011, 4AKE EFFECTS FLAG. 0   
        - SOURCE STRENGTnS ( CURIES PEfC TEU   ) .
         SEUOI4 1 SEUON 2 l'ifUO", J nUON 0 
         '.45000Et02 7.05000[+02   
 . 5 SUC" -lnI0.00 -580.00 1.00 0.00 GAS E.IT TE~P (OEG k). 2~4.20, GAS ExIT VEL. ("/5[C). 5.TO, 
        STACK OIAIIETER (~). ].500' HEIGHT 0' AS60. KLOG. (PI). 0.00, WIDTH 0'
        IS50. ('LOG. (M" 0.110, M'''E EFFECTS FLAG. 0   
        . SOU~CE STRENGTHS ( CURIfS PER YEAR   ) -
         SEASON 1 SEASON l SEASON] SEASON 4 
         II. 01l000Et02 3.nOOOE+02   
 . II STAC" 310.00 -~50.00 1.00 0."0 GAS EIIT TE"P (DEG K). 2~'.lO, CAS EIIT iEL. ("/SEC). 27.30, 
        5'ICK oIAHETr~ (M). 3.500, HEIGMT OF ASSO. BLDG. (H). 0.00, IIIOTH 0'
        '5S0. aLOr.. (H). 0.01), MAKE EFFECTS FLAG. t'   
        . SOUACE STRE~G'HS ( CURIES PEA YEAR   ) .
         SEASON I SEASON 2 SEUON 3 II!UON 0 
         3.nOoOE+ol 3.85000E+0l   
 . 7 STACi( -7110.0n -1~30.00 1.00 0.00 GAS EWIf TEMP (OEG k). lRO.lO, GAS EXIT VEL. (H/SEC). 9.00, 
        sTACK OIAMETE~ (M). ].500, HEIGHT 0' AS80. BLDG. (M). 0.00, IIIDTH 0'
        ~SSO. tlLDG. "'). 0.00, NAkf. EFFECTS FL~ . 0   
        . SOVRtE STRENCTHS ( CUAlfl PER YEAR   ) .
         SEASON I SUSON 2 SEASON J SEASON 0 
         S.70000EtOI 8.70000[+01   

-------
.... !SCLf
Table B-3.
eeeeeeee PAGE
.............
~t~. II WIth V.~ttc.1 ,"d Ho~l.o"t.1 V'"t,
- 10URCE INPUT DATA (CONT.) -
....-...--.-.-.-.-.-..-..-..-..-.-------..-..-......-.----_.....-...............-...........................-...........-.......
I e 8TAr~ d5a.dO 100.00 1.00 0.00 GAS EXI' TEHP (DE& K)' 2e4.20, GAl EXIT VEL. (H/SEC)' 33.30,
STACK OrAHETER (M). 3.500, HEIGHT 0' ASSO. BLDG. (H). 0.00, MIDTH 0'
ASSO. 8LOG. (M). 0.00, MAkE E,FECTS FLAG. 0
- SOU~CE ITRENGTHS ( CURIES PER YEAR
SEASON 1 IEASON 2 SEAION 3
0.00000E+02 4.04000E+02
0.00 GAl EIIT TEMP (rEG K)' 280.20, GAS EXIT VEL. (M/SEC). '.'0,
STACK DIAMETER (M). 0.000, HEIGHT OF ASSO. BLDG. (H). 0.00, MIDTH 0'
ASSD. 8LOG. (M)' 0.00, WAkE EFFECTS FLAG. 0
- SOURCE 8TAENGTHS ( CURIES PER YEAR
SEASON 1 &EASDI! 2 SEAsO" 3
3.20000E+02 3.20000E+02
0.00 MIOTH 0' AP.EA (~). 4.00
- SOIlIlCE STRENGT"S (PER CURIES PER YEAR IQUAA[ "!TEN
SEASON I IEASOU Z SEASON 3 I£AION 0
0.6QOOOE+01 0.6'000E+01
12 AND POINT X,y. 500.00, 05.00 II LESS THAN PERMITTED
000.00 1.00 0.00 ~IOTH 0' AREA (H). 0.00
- SOURCE ITPENGTHS (PER CURIES PfR YEAR SQUARE HETEN
SEASOIf I 8EAION 2 SEASON 3 Sr.~SON 4
1.73000E+01 1.73000E+0'
13 ANO POINT X,y. 500.00, 337.50 IS LESS THA" PERMITTED
-800.00 1.00 0.00 GAS EXIT TEHP COEr. K)' 280.20, GAS EXIT VEL. ("/SEC)' '1,10,
STACk DIAHETER (~). 2.500, HEIGHT 0' ASSO. 8LD~. (M). 0.00, MIDTH 0'
.550. ALDG. (M). 0.00, MAKE E'FECTS FLAG. 0
- SOURCE STHE~r.THS ( CURIES PER YEAR
SEA~ON 1 SEASOIf l SfAIOM 3
2.'~000E+02 2.'8000E+02
14 AND P~INT X,Y. 1000.00, 135.00 IS LESS THAN PEHMITTED
"60.00 1.00 0.00 WI~TH 0' AREA (M)' 5.00
- SOURCE STRENGTHS (PER CURIES PE~ YEAR 'QUARE METER
~EASON 1 8USOh Z SUSON J SEUO" .
2.22000E+00 2.22000(+00
C T SOURCE SOURtE
A A N""'BEI! TYP(
It P
o (
I
10
suc"
I
IZ
APE A
.(
cnOP[,INATE
(~)
q~(I.OO
1M.OO
td
I
N
o
.'''HlsG - OIS""CE RETwEEN SouRCE
. 11 ,n[a -100.00
.AItHING - DISTANCE OET~~E~ SOURC~
. 10 STAC~ 710.00
WAItNING - DISTANCE 5~TwEf~ SOuRCE
. 15 '~E' 580.Qn
Y
COOROI~ATE
(P,)
E~ISSJON
If EIGHT
( ")
8AS[ I
ELEV- I
&TION I
(1'1) I
- SOURCE DETAILS DEPENDING ON TYPE -
SEUON .
-500.00
1.00
8[UO" 0
i'o.on
'.00
SEA80N .
. ee.e
» .
J .
J -
) .
J .
) .

-------
Table B-3.
.... ISCLT .............
"I~. 11 With V.rttc.1 I"d "orllo"tll VI~tl
...
,~~U'L ~ROU~P LEVEL CONCfNTRATION
( PICO CURl!' PER LITER
. GRID SYSTE~ N!C!PTDRS .
- x 'XIS (R'NG! , "ETEnS) .
1000.000 2000.000 3000.000
CONC!NTAntO'l
  ........ PAG! 5 ..1.
) 'PO" ALL SOURCES COHBINED ..
1000.000 5000.000 1000.000 8000.001
200.0~0 50".000
, AXIS (.zr:II/TH q[IP.I'IG, OEGPHS )
-------.----------------.-.-----------.-.-.-.-----.-.---------------.-.-....-.....-........-.-.............-........
 337.500 1.8709bl 0.03Hbfl 0.3382/19 O.I05lh 0.057997 0.039411 0.019149 0.019132 0.01'1"
 Jl'5.0'0 1.201''''0 1.02B570 0.211410 0.0939~5 0.0"2Gl 0.010991 0.03180' 0.OU795 0.018722
 292.500 1.005J50 lI.b29901 0.<'b5bl0 0.0''11183 0.055351 0.019200 0.030121 0.020109 0.017118
 270.0cr 0./137021 0.070717 11.190153 0.087283 0.01»0004 0.0411009 0.017228 0.GlU03 0.02J.,0
 247.500 1).741'i09 o. ~6Z7b1l C.?0Il!l26 0.01l297 0.008185 0.03'51121 0.028119 0.019381 0.01""
 225.1)(10 0.7.HIIII' 0. ulloZ33 0.26JI>J8 0.115902 0.071»1137 0.05731 t 0.005150 0.011793 0.02nlb
 202.5~0 0.il111C15 0.'jtor,50 '1.305579 0.1611184 0.110122 0.0892711 0.073108 0.053U5 0.0""0
 180.0UO (:.9~3~511 0.6I1a'HI 0.3"3885 0.1491172 0.101053 O. 013b110 0.051353 0.038972 0.0333".
 157.500 1.(1'52°10 1).71501 a 0.3021)72 O.IUIISI 0.1111039 0.0~9581 0.012]]4 It.OSU02 0.0"'0.
 \J~.IIO(l 1.(>lJI51> 11.707715 0.1120021 0.IU880 (1.095335 0.01>1>B91> 0.051152 0.031110 o.onon
 112.501) 2.1101'37 1.201'1911 0.':11 a2 J9 0.133090 0.074519 0.050192 0.037212 0.023914 O.OZO075
 90.00(1 2.7J99')9 2.~1)9021 0.351>031> 0.1'55027 0.oenOll7 0.0701/12 0.054509 0.031212 0.011")
 b7.5('" 2.Q~ltI~0 7.2111555 0.1)51119 0.IH2!)9 0.070875 0.0479110 0.0151132 11.02294' 0.01"71
 oS.Or.~ 2. 320'i1l9 0.BtoA28 0.5006(10 0.121570 0.OU:!85 0.042311 0.011255 0.020219 0.0170"
 22. ~Oll 1.71'571>11 2.5c?1'5'13 0.5333<111 0.304089 0.0711011 0.00'1658 O.03l1blll 0.On1»58 0.01"19
 I) .'JOII l.'11~112 2.1'12571 0.4U1I5115 0.15983) 0.080395 0.0501156 0.001301 0.02705t O. 02JJn
t;J:I          
1    . 'RI~ S'S'[~ REC,pTOPS.    
N    ...   
......    . I( UIS (RtNG[ , "ET[MS) .    
  900(l.O!lO 10011(1.000 15000.000 2011110.000 30000.000 50000.000   
 , AIlS ('ZI"UT~ fot:Ar.III[;, OEt;IIHS )  CI,l'lCE"TAATJO!4    
----.-.----.----.---------------------.-.-.-------.-.-..---..---.....-.-.-.-........................................
,
3]7.500 0.013'135 0.012200 0.007350 (1.00513' 0.003123 0.00""0
J15.0uO 0.010351 0.1)100ClII 0.00897b 0.00631» 0.003921 0.002110
2"2.5UO 0.0111'"1 0.Cn055 0.007'151> 0.005585 0.00311011 0.0018]5
no.o"" 0.02"IIZ<, 0.lJliJ22l 0.0111>01 O. 008Ho 0.005207 0.002h]
2G7.5011 1I.0Id';)1 0."1211~2 O.0079~O 0.0051>01» 0.0030]7 0.001855
225.0110 c.u211160 0.1I2151'S O.01Jb20 0.009791 0.0011112 0.003]91
~02.50" 0.U11 H2 O.IIHOI>I 0.0i!391'b 0.(l17aZ!l 0.011023 0.0011107
IlIn.OUII 0.u2'10011 II.Ol5511" 0.(11511/45 0.010'194 0.0011698 0.0031101
1S1.50l' 1I.0}?1311 0.030305 0.0218711 0.1115')109 0.011'11114 0.005214
13"'.(1110 O.oi!;IQf, 0.022103 0.0133'15 0.009356 0.0056b7 0.003026
11l.'iOO 0.0171'1' 0."10'175 0.0118"06 11.11060510 0.003&07 0.001'102
?o .0.10 0.(1277811 11.02053. 0.015"~5 0.0101)02 0.006517 0.00352t
.7.~01) 11.111'>')00 0."10419 1).1I01l'i1l1l 11.005'13. 0.00]571 0.001902
4~.(II}1I 1).(110.72 (I.oU"IJO 0.007670 11.0/)5]57 0.003222 0.0017l0
2<'. 'iIIU 1'.01715') 0.01119115 0.01l~905 11.006110 0.00]700 0.00199)
".OCl' O.II?\I;>/41> 0."173(17 O.oIO!lo] 0.1107619 0.011111151 0.00250'1

-------
INDUSTRIAL SOURCE COMPLEX LONG-TERM MODELING RESULTS FOR CASE STUDY
UNDERGROUND URANIUM MINES (MINE 12), MODELED WITH ACTUAL VENT ORIENTATION
(Table B-4)
B-22

-------
Table B-4.
........ 'AGE
.... rsCL T
..............
"I". 12 ~Ith V.rttc.1 .nd Ho,I,o"t.' ve"t.
- snURCE INPUT DATA -
C , SQURI:!
A A HU';1;[ ~
" ,
o f
$(.III.C~
TVP[
.
COOiHHNATE
(:~ )
V
COORDINATE
(rI)
EtlUS ION
tiEIG..T
( It)
IAS! I
EL.EV- I
AUON I
(I'.) I
- SOURCE DETAILS OEPENOI~G ON TVPE -
J ....
.....-.--_.---~_.__._.-------------_._-------------_.------.--..-.-.-.-.......---..-.-.---.........-.-.-....-...........-.......
I  AIiE 4 ISII.III! -100.00 0.00
'''UNI'IG - 'DUU':CE BI';ThF:[t; Sr.JllqCE I ANO POI"'T
"ARNluG - OISTa-rCE BE T/(H'I snuRCt: I 41.0 PorNT
I \ AI'[l 2'50.00 -100.00 0.00
w,ltlUt:G - 015T",CE IIET~EEII SouRCE J "jD POI"T
II 5 STACK -/.o.uo -110.00 I.on
b:1
I
N
W
-250.00
1.00
II
SUC'"
-~0.01)
II
_AItNI.,G - OISTA~CE ~~T.EE1 SOURCE
II ''10 POINT .,y.
0.00 WIDTH 0' AREA (W). 0.00
- SOURCE STRENGTHS (PER CURJES PEA YEAA SOUARE W~TER
SEASON 1 SEASON 2 SEASON J SEASON 0
0.021100E+01 4.02000EtOI
200.00, 112.50 IS LESS TtiAN PERMITTED
200.00, 135.00 15 LESS THAN PEH~ITTEO
wIDTH OF AREA (M). 4.00
- SQURfE STRENGTHS (PER CURIES PER YEAR S~UARE METEA
SEASON 1 SEASO~ 2 SEASON J SEaSON 4
5.0100l1EtOI ~.01000EtOI
.,V. 200.00, 112.'50 IS LESS THAN 'EAMITTED
0.00 GAS EIIIT TEHP (OEG K). 280.20, GAS EIIT VEL. (M/SECI. 1'.40,
STACK olAHETER (~). 5.001), HEIGHT 0' ASSO. BLDG. (MI. 0.00, HIOTH 0'
AS30. ALOG. (~,. 0.00, MaKE EF'ECTS FLAO . 0
- SOURCE STRENGTHS ( CURIES PEN YEAR
SEASON 1 SEASON 2 SEASON J
5.00000E+02 ~.00000Et02
0.00 GAS EXIT TENP (OEG K). Z~0.211, GAS EXIT YEL. (~/SEC). 18.00,
STACK OIAHETEA (M). 5.00", HEIGHT 0' .SIO. BLDG. (II). 0.00, WJDTH 0'
ASSO. &LDG. 1M). 0.00, WAKE EFFECT~ FLAG. 11
- SOURCE STAENGT'!! ( CURIES PEA YUA
8E480N I ~Ea'ON l SEASON J
'.~OOOOEtOl 1."OOt.E+Ol
202.50 IS LEIS T~'N PEAMITTED
II,Y.
x".
0.00
IUION 4
IUIDN .
ZOO.Oo,
) .
) .
) -
) .

-------
Table B-4.
..
IN~UIL GROl"II> Llyn Ci!t:CENTRI TlOII
( PIca CURIEl PER LITER
- GRID SYSTE~ RECF.PTORS -
- X AXIS (RANGE, METERS) -
1000.0"0 2000.000 ]000.000
CONCENTPATION
  ........ PAGr; . ....
) FRON ALL SOURC[S C0I181NEO ..
4000.000 5000.000 1000.000 8000.000
.... ISCLT .....,.......
HI", 12 WIth y"tlcal ,"d HorlIO"t" v,"t.
lO~.OOO 500.000
, AXIS (AlI:'uTt< KEaPI'IG, OEliREES )
-.----.-....--.-.---.--------...------.-.-.-------.-.------...------.-...-.---.---.......----....-.-.......-........
 337.500 1.11551111~ 0.';1I09l O~ 194995 0.06'292  0.03.,.77 0.02118U 0.018045 0.011111 O.OO9US
 ]1';.000 1.329922 0.5121\54 0.209185 0.0191128  0.0041129 0.029947 0.0219" 0.013794 O.OU'"
 292.';00 1.21H12 0.44~":iC;5 0.I19u'S1 0.0111]99  0.031h5 0.0252115 0.0111572 0.OU688 0.0097!10
 210.0110 1.,)~2'HI 0.633024 0.2111708 0.104070  0.0'58935 0.0]9IUI~ 0.029004 0.018272 0.01525'
 147.5110 2. \111/)0 39 11.70(11178 0.236911 0.01'11'04  0.(142539 0.0275115 0.019906 0.01Z290 O.OIUOI
 225.000 2.1I\5~C!1 0.1171181 0.309223 0.12151~  0.0~8789 0.041>10~ 0.013911 0.UU51 0.017'51
 202.500 2.79~5"3 1.3'31'2" 0.6013\8 0.2260110  0.125882 0.OU931 0.0615"6 0.0]81]6 0.031)"
 \'10.000 5.4ellO?1I 2.7813118 0.1020110 0.194300  0.0955211 0.0591]5 0.012190 0.025371 0.020180
 \57.500 1~."02059 3.40"6'14 0.781111]1 0.2)')152  O. U31151 0.079733 0.051194 0.035 3i!9 O. oz.zeo
 135.0"0 ..?;j~"C.3 4.9'19204 0.710311 0.U1l181  0.0110511 0.050010 0.035256 O.OZUt9 0.011lU
 \l2.!lII') 0.01\152\ 2.""II?29 0.00)]28 0.0991181  0.04'10]0 0.031131 0.01l094 0.0133118 0.0&1001
 'III. !lOll  12.1001\22 2.32918] 0.57251)3 0.1631115  0.084011 0.050008 0.0111112 0.02J8JZ 0,01''''
 /)7.50(1 5.41HIIQ 1.303370 0.]1001\0 0.089135  11.005889 0.029011 0.0210n 0.012901 0.010"0
 05.000 3.318"<18 1.r-41IH 0.274'1'0 0.08h25  0.012711 0.027394 0.01960. 0.0119411 o.onne
 Z2.~I1" 2.21\0~bl lI.fo?]112 0.211'1172 0.09(1'103  0.0071"9 0.030801 0.0221511 0.OU5U O.OU2I1
 ".0(11) I. '5~77l'5 0.'5810IlQ 0.21158711 0.0'13758  0.0527u5 0.03511111 0.025816 O.01U9I o.oUen
b:'            
I     - CRID BYST!" R!Cr;'TOAS -    
N     - x AXIS ("A~Gr;  "!TERs) -    
.I::'-     ,    
  '0''''.01)0 10000.000 I~OOO.OOO 211"00.000  ]0000.000 50000.000   
, AIlS (IZt"UTH BE1PI"i., h£GIIE£S )  COliC!",,,, TI ON    
 ...---..-.-...--.-.-----.-.-.------.--.-.-----.---.-.--.-.--.---.-.-.-....-.-..-.-.........................-..-.....
        I    
 ]]7.'S~0 0.(1(17"51 0.(l1!~1I5 0.(10]9112 0.002..0  0.001571 O.OOO~]O   
 31'S.00C 0.0"'1790 (1.00"1\8<1 O.OOIl'HO o.oon81  1I.0020U O.OOIOflft   
 2'12.'51)0 u.006H" 11.11072118 0.U01l199 0.00268]  11.001718 0.000901   
 2111.11:>11 0.;113"17 0.11113113 O. O(ltll. 11 0.0011511]  0.0027311 0.0011155   
 207.%11 o.0~6Ito3 lI.on14'12 0.001l1)] (I.1I029/)1  0.0017100 0.000'127   
 ?i!'5.000 0.0152Q1 0./113248 0.1107711 0.1)05390  0.0032117 0.0017110   
 2')2.0;"0 'J.U2111.1 0.""<101>" 0.0IH}5 0.00'11125  0.005'128 0.0113183   
 I'-".'~ 0 ".,,171,11> o. '1151,,11 0.001\'.)98 1I.I)O!l1!38  0.00H3/) 0.0017'19   
 157 .SUO II.02111\;J3 ".12111111 0.0123511 0.00P'Q39  0.005001 . 0.002b]2   
 135.0011 0.1)\4720 u.'\21>'55 0.0117\"3 0.0008111  0.002851, 0.001490   
 IH.'H'" 0.\"1'1'&.) 0.nU7111!! 0.0011'; Ii! 0.003001  0.001782 0.00092"   
 '10.000 0..)\/)71'1 0.01111129 0.0l)IH'!>9 0.0051>"3  0.00]]110 0.001158   
 117.5011 0.0"""21 0.'107715 O.OIlHJ7 0.00]0111  0.lInt777 0.000931   
 I!>.O~(I 0.(111(0)25 1).00711111 0.00/11112 0."02759  0.0l)U21 0.01)01147   
 l2. ~')O II." (1'1 ''''5 "./111111112 0.(100"1>5 ".011311111  O.oolhJ 0.000'175   
 ". "U(' O.~I\II~" 0.""'19111 0.01l'i7<;" 0.003'113  0.(11123113 0.00123b   

-------
POPULATION AROUND SELECTED UNDERGROUND URANIUM MINES
(Table B-5)
B-25

-------
   Table B-5.    
Population around selected underground uranium mines (Br84) 
Mine State  Distance from mine Oem} 
   0-1/2 0-1 0-2 0-3 0-4 0-5
sunday Colo. 0 0 0 0 0 0
King Solomon Colo. 0 0 0 0 0 0
Velvet Utah 0 0 0 0 0 0
Tony M Utah 0 0 0 0 0 0
Hack Canyon Arizona 1 1 1 1 1 1
Pidgeon Arizona 0 0 0 0 0 0
Kanab North Arizona 0 0 0 0 0 0
De rmo-snyder Colo .IUtah 0 5 21 49 67 83
Wi1son-        
Sllverbe11 Utah/Colo. 0 0 0 12 20 23
Lisbon Utah 0 0 0 4 44 44
LaSal Utah 0 0 53 101 194 194
Hecla Utah 16 16 20 40 73 73
Big Eagle Wyoming 0 0 0 0 0 0
Golden Eagle Wyoming 0 0 0 6 6 6
Sheep Mtn. Wyoming 0 0 0 0 0 12
Mt. Taylor New Mexico 0 100 311 336 336 336
Old Church        
Rock New Mexico 9 9 70 139 187 364
Church        
Rock-NE New Mexico 0 11 22 26 31 31
Church        
Rock-1 New Mexico 0 11 22 27 31 31
Church        
Rock-East New Mexico 0 0 9 57 70 131
Kerr-McGee        
Sec 30 East New Mexico 3 3 3 3 3 3
Kerr-McGee        
Sec 30 West. New Mexico 0 5 5 5 5 6
Kerr-McGee        
Sec 19 New Mexico 0 0 0 4 4 4
Kerr-McGee        
Sec 35 New Mexico 0 0 0 0 0 0
Kerr-McGee        
Sec 36 New Mexico 0 0 0 0 0 0
B-26

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   Table B-5.       
Population around selected underground uranium mines (Br84)' (Continued)
Mine State  Distance from mine (kIn)  
 0-1/2 0-1 0-2 0-3   0-4 0-5
Homestake          
Sec 23 New Mexico 0 0 0 3   3 4
Homestake          
Sec 25 New Mexico 0 0 0 0   0 0
Nose          
ROck(a) New Mexico 0 0 0 0   26 35
Mariano          
Lake New Mexico 13 44 15 196   214 352
Schwartz-          
walder(a) Colorado 3 3 63 102   136 141
Totals  42 205 618 1.009 1.315 1.133
(a)The population around this mine is not included in the total 
because the location is not typical of the industry.    
BR84
Bruno G. A., Dirks J. A., Jackson P.O., and Young J. K.,
U.S. Uranium Mining Indu8try: Background Information on
Economics and Emissions, Pacific Northwest Laboratory,
PNL-5035 (UC-2, ii, 51) March 1984.
B-27

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APPENDIX C
CALCULATIONS ON BULKHEAD EFFECTIVENESS
AT VARIOUS AIR REMOVAL RATES
C-l

-------
 Table C-l. Effectiveness of a bulkhead in reducingG~don-222
  emissions--with zero percent air removal rate a 
 Radon-222 Daily radon-222 Daily radon-222 Radon decay
Day (pCi/L) decay removal (%)
 (cO (cO
1  8900 4.91E-2 0 8
2  16300 1. 36E-1 0 23
3  22500 2.09E-1 0 36
4  27700 2.70E-l 0 46
5  32100 3.21E-1 0 55
6  35700 3.63E-1 0 62
7  38700 3.98E-1 0 68
8  41200 4.28E-1 0 74
9  43300 4.53E-1 0 78
10  45100 4.73E-1 0 81
11  46500 4.91E-1 0 84
12  47800 5.05E-1 0 87
13  48800 5.17E-1 0 89
14  49700 5.27E-1 0 91
15  50400 5.35E-1 0 92
16  51000 5.42E-l 0 93
17  51500 5.48E-1 0 94
18  51900 5.53E-1 0 95
19  52200 5.57E-1 0 96
20  52500 5.61E-1 0 97
21  52800 5.63E-l 0 97
22  53000 5.66E-l 0 97
23  53100 5.68E-l 0 98
24  53300 5.70E-l 0 98
25  53400 5.71E-l 0 98
26  53500 5. 72E-l  0 98
27  53600 5.73E-l 0 99
28  53600 5. 74E-l 0 99
29  53700 5.75E-l 0 99
30  53800 5.75E-l 0 99
31  53800 5.76E-l 0 99
32  53800 5.76E-l 0 99
33  53900 5.76E-l 0 99
34  53900 5. 77E-l  0 99
35  53900 5.77E-l 0 99
36  53900 5. 77E-l  0 99
37  53900 5. 77E-l 0 99
38  53900 5. 77E-l  0 99
39  54000 5. 77E-l 0 99
40  54000 5. 77E-l  0 99
(a) Removal rate: percent of total volume of air in sealed area which
 is removed per day.   
Emanation: 5.78 x 10-lCi/day.   
Flux rate: 9.29 pCi/ft2-sec.   
Drift size: 14 ft x 10 ft x 15000 ft.   
Drift volume:: 2,100,000 ft3.   
    C-2   

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Table C-2. Effectiveness of a bulkhead in reducin~ 5adon-222
emissions--with 10 percent air removal rate a
Day
Radon-222
(pCi/L)
Daily radon-222
decay
(Ci)
Daily radon-222
removal
(cO
Radon decay
(%)
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
26
27
28
29
30
31
32
33
8480
14900
19700
23400
26200
28200
29800
31000
31900
32600
33100
33500
33800
34000
34200
34300
34400
34500
34500
34600
34600
34600
34700
34700
34700
34700
34700
34700
34700
34700
34700
34700
34700
4.75E-2
1. 27E-1
1. 86E-1
2.32E-1
2.66E-l
2.92E-1
3. 11E-l
3.26E-l
3.37E-l
3.45E-l
3.52E-l
3.57E-1
3.60E-l
3.63E-l
3.65E-l
3.67E-l
3.68E-l
3.69E-l
3.69E-l
3.70E-1
3.70E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
3.71E-l
2.64E-2
7.04E-2
1.04E-l
1.29E-l
1.48E-l
1. 62E-l
1.73E-l
1.81E-l
1.87E-l
1.92E-l
1. 95E-l
1. 98E-l
2.00E-l
2.02E-l
2.03E-l
2.04E-l
2.04E-l
2.05E-l
2.05E-l
2.06E-l
2.06E-l
2.06E-l
2.06E-l
2.06E-l
2.06E-l
2.06E-l
2.06E-1
2.06E-l
2.06E-l
2.06E-l
2.06E-l
2.06E-l
2.06E-l
8
21
32
40
45
50
53
56
58
59
60
61
62
62
63
63
63
63
63
64
64
64
64
64
64
64
64
64
64
64
64
64
64
(a) Removal rate: percent of total volume
is removed per day.
Emanation: 5.78 x 10-lCi/day.
Flux rate: 9.29 pCi/ft2-sec.
Drift size: 14 ft x 10 ft x 15000 ft.
Drift volume:: 2,100,000 ft3.
C-3
of air in sealed area which

-------
Table C-3. Effectiveness of a bulkhead in reducing 5adon-222
emissions--with 20 percent air removal rate{a
Day
Radon-222
(pCi/L)
Daily radon-222
decay
(ci)
Daily radon-222
removal
(ci)
Radon decay
(%)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
8090
13600
17400
20000
21800
23000
23800
24400
24800
25000
25200
25300
25400
25500
25500
25500
25500
25500
25600
25600
25600
25600
25600
25600
4.60E-2
1. 18E-1
1. 67E-1
2.01E-1
2.24E-1
2.40E-1
2.50E-1
2.58E-1
2.63E-1
2.66E-1
2.69E-1
2.70E-1
2.71E-1
2. 72E-1
2.73E-1
2.73E-1
2.73E-1
2.73E-1
2.74E-1
2.74E-1
2.74E-1
2. 74E-1
2.74E-1
2. 74E-1
5. 12E-2
1. 31E-1
1.86E-1
2.23E-1
2.49E-1
2.66E-1
2.78E-1
2.86E-1
2.92E-1
2.96E-1
2.99E-1
3.00E-1
3.02E-1
3.02E-1
3.03E-1
3.03E-1
3.04E-1
3.04E-1
3.04E-1
3.04E-1
3.04E-1
3.04E-1
3.04E-1
3.04E-1
7
20
28
34
38
41
43
44
45
46
46
46
46
47
47
47
47
47
47
47
47
47
47
47
(a) Removal rate: percent of total volume of air in sealed area which
is removed per day.
Emanation: 5.78 x 10-lCi/day.
Flux rate: 9.29 pCi/ft2-sec.
Drift size: 14 ft x 10 ft x 15000 ft.
Drift volume:: 2,100,000 ft3.
C-4
.

-------
Table C-4. Effectiveness of a bulkhead in reducin~ ~adon-222
emissions--with 50 percent air removal rate a)
 Radon-222 Daily radon-222 Daily radon-222 Radon decay
Day (pCi/L) decay removal (%)
 (cO (cO
1 7060 4.20E-2 1.17E-l 7
2 10600 9. 68E-2 2.69E-l 16
3 12400 1. 25E-l  3.46E-l 21
4 13400 1.39E-l 3.85E-l 23
5 13800 1.46E-l 4.05E-l 25
6 14100 1.49E-l 4.15E-l 25
7 14200 1. 51E-l 4.20E-l 26
8 14200 1.52E-l 4.22E-l 26
9 14200 1.52E-l 4.24E-l 26
10 14300 1.53E-l 4.24E-l 26
11 14300 1.53E-l 4.25E-l 26
12 14300 1. 53E-l 4.25E-l 26
13 14300 1. 53E-l 4.25E-l 26
14 14300 1. 53E-l 4.25E-l 26
(a) Removal rate: percent of total volume of air in sealed area which
is removed per day.
Emanation: 5.78 x 10-lCi/day.
Flux rate: 9.29 pCi/ft2-sec.
Drift size: 14 ft x 10 ft x 15000 ft.
Drift volume:: 2,100,000 ft3.
C-5

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APPEND IX D
ESTIMATED COSTS OF BLEED STREAM
CONTROL WITH ACTIVATED CARBON
D-l

-------
Table D-l.
Capital costs for radon-222 control(~~ underground
uranium mines with activated carbon
Filter
Carbon adsorber, 1800 pound bed
Carbon adsorber, 150 pound bed
(qty)
Electric heater, 75 kilowatt
Air cooling system
550-ft2 stainless steel heat
exchanger: system 1 and 2
2 tons of refrigerant: system 3
Dehumdifier
Blower with motors (qty)
Automatic radon-222 detector

Total equipment cost
Instrumentation
Piping
Electrical
Foundations
Structural
Sitework
Painting and insulation
Field overhead
Engineering (10 percent)
Freight
Taxes (6 percent)
Spares

Total installation cost
Equipment and installation
System 1
1,800
42,600
15,000 (2)
500
20,000
o
2 , 000 (3)
16,900
$98,800
6,500
5,600
8,400
2,100
2, 100
5,300
1,100
8,800
17,300
2,800
6,000
8,400

$74,400
$173,200
(a) Based on 100 cfm for bleedstream vent.
D-2
System 2
1,800
42,600
7,500 (1)
500
20,000
5,000
1,400(2)
16,900
$95,700
6,400
5,200
8,300
1,900
1,900
5,000
1,000
8,500
16,700
2,800
5,700
8,300

$71,700
$167,400
System 3
1,800
42,600
o
o
51,000
o
700(1)
16.900
$113,000
7,800
5,400
9,000
2,400
2,400
6.500
2,200
10,800
19,800
2,200
6,800
9.500

$84.800
$197.800

-------
Table D-2. Electrical usage
In annual kilowatt hours based upon three shift operation
260 days per year
System 1
75 kw heater - 1.1 hours per day
Three blowers. 6 horsepower total
Lighting. instrumentation. etc.
Total
21.500
27.900
20.000
69.400
System 2
75 kw heater - 1.1 hours per day
Two blowers. 4 horsepower total
Lighting. instrumentation. etc.
Total
21, 500
18.600
20.000
60. 100
System 3
2 tons of refrigeration. 24 hours
Blower. 3 horsepower
Lighting. instrumentation. etc.
Total
per day
187.200
14.000
20.000
221.200
D-3

-------
  Table D-3. Annualized costs for radon-222 control in 
   underground uranium mines with activated carbon 
      System 1 System 2 System 3
A. Direct operating charges    
 1. Electricity at 5 cents per kw $3,500 $ 3,000 $11 , 100
 2. Replacement carbon at $2.50 per 1,100 1,100 900
  pound     
 3. Operating labor    
  a. Direct - 390 hours at $9.15 3,600 3,600 3,600
  b. Supervision - 20 percent of 700 700 700
   direct labor    
 4. Maintenance - 6 percent of 10,400 10,000 11 , 900
  capital cost     
B. Capital charges     
 1. Overhead   2,200 2,200 2,200
  a. Plant - 50 percent of 3 and 4 700 700 700
  b. Payroll - 20 percent of 3   
 2. Fixed costs     
  a. Capital recovery, 15 percent, 38,600 37,300 44, 100
   8 years     
  b. Taxes and insurance - 5 8,700 8,400 9,900
   percent     
C. Total    $69,500 $67,000 $85,100
D-4

-------
back of drift:
curie (Ci):
cut-and-fill stoping:
Developing stope:
Drift:
drift surface:
extracting stope:
haulage drift:
HydrEpoxy 300:
half-life of radon:
muck:
ore:
ore body:
GLOSSARY
The roof of a drift.
A source of radionuclide which undergoes radio-
active decay of 3.7 x 1010 disintegrations per
second.
A stoping method in which the ore is excavated
by successive flat or inclined slices, working
upward from the level. After each slice is
blasted, all broken ore is removed, and the
stope is filled with waste before the next slice
is taken out.
Stope in which development drifts are being
driven to gain access to ore.
A horizontal opening in or near an ore body and
parallel to the course of the vein or the long
dimension of the ore body.
Exposed surface of drift.
Stope in which the ore is being extracted.
Drift developed for movement of men, supplies,
waste, and ore.
Two-component, water-base epoxy manufactured by
ACME Chemical & Insulation Company.
Time in which a half of radon will decay.
Ore broken in process of mining.
Mineral of sufficient value as to quality and
quantity which may be mined with profit.
Mineral deposit that can be worked at a profit.
G-l

-------
I
orepass:
Vertical or inclined passage for the downward
transfer of ore.
picocurie (p'i):
10-12 curie; 0.037 disintegration per second.
raise:
Vertical or inclined opening driven upward from
a haulage level to the ore level.
reference mine:
The hypothetical mine selected for this study.
ribs of drift:
Side of a pillar or the wall.
room-and-pillar stoping: Stoping method in which the ore is first mined
in rooms and then ore in the pillars is subse-
quently mined.
shotcrete:
Pneumatically applied portland cement mortar.
slusher:
Mechanical dragshovel loader.
stope:
Unit excavation from which ore is being, or has
been, excavated in a series of steps.
G-2

-------