NCRP report no 118 radiation protection in the mineral extraction industry

NCRP REPORT No. 118

RADIATION PROTECTION
IN THE MINERAL
EXTRACTION INDUSTRY
Recommendations of the
NATIONAL COUNCIL O N RADIATION
PROTECTION AND MEASUREMENTS

Issued November 30,1993

National Council on Radiation Protection and Measurements
7910 Woodmont Avenue
1 Bethesda, MD 20814-3095


LEGAL NOTICE
This report was prepared by the National Council on Radiation Protection and Measurements (NCRP). The Council strives to provide accurate, complete and useful
information in its reports. However, neither the NCRP, the members of NCRP, other
persons contributing to or assisting in the preparation of this Report, nor any person
actingon the behalf of any of these parties: (a) makes any warranty or representation,
express or implied, with respect to the accuracy, completeness or usefulness of the
information contained in this Report, or that the use of any information, method or
process disclosed in this Report may not infringe on privately owned rights; or (b)
assumes any liability with respect to the use of, or for damages resulting from the
use of any information, method or process disclosed in this Report, under the Civil
Rights Act of 1964, Section 701 et seq. as amended 42 U.S.C. Section 2000e et seq.
(Title VII) or any other statutory or common law theory governing liability.

Library of Congress Cataloging-in-Publication Data
National Council on Radiation Protection and Measurements.

Radiation protection in the mineral extraction industry : recommendations of
the National Council on Radiation Protection and Measurements.
cm.-(NCRP report ; no. 118)
p.
"Prepared by Scientific Committee 46-2 on Uranium Mining and MillingRadiation Safety Programs"-Pref.
"Issued November 30, 1993."
Includes bibliographical references (p. ) and index.
ISBN 0-929600-33-9
1. Mine safety. 2. Ore-dressing plants-Safety measures. 3. RadiationSafety measures. I. National Council on Radiation Protection and
Measurements, Scientific Committee 46-2 on Uranium Mining and MillingRadiation Safety Programs. IT. Title. 111. Series.
TN295.N28 1993
622l.8-dc20
93-33554
CIP

Copyright O National Council on Radiation
Protection and Measurements 1993
All rights reserved. This publication is protected by copyright. No part of this publication may be reproduced in any form or by any means, including photocopying, or
utilized by any information storage and retrieval system without written permission
from the copyright owner, except for brief quotation in critical articles or reviews.


Preface
This Report was originally intended as radiation protection recommendations for the uranium mining and milling industry. The Committee early on, however, recognized t h a t there were known
radiation problems connected with the mining and milling of several
minerals. Further, the Committee recognized that the extraction
and processing of virtually any mineral might result in some level
of radiation exposure and that the application of radiation protection
practices may be warranted in some cases. Therefore, the Report
that evolved addresses the whole mineral industry and the material

prepared for the uranium mining and milling industry was retained
to provide examples of the more complex problems encountered and
solutions to those problems.
The Report was written for a specific audience-management and
its technical staff-who either have been made aware of radiation
problems by the imposition of a regulation or perceive the importance
of evaluating facility design and operations in the societal context
of a greater awareness about occupational and environmental risks.
The International System of Units (SI) is used herein and, in
accordance with the recommendations set forth in NCRP Report
No. 82, SI Units in Radiation Protection and Measurements, the use
of conventional units has been discontinued. Appendix B contains
a conversion table of SI units and conventional units.
This Report was prepared by Scientific Committee 46-2 on Uranium Mining and Milling-Radiation Safety Programs, working
under the auspices of Scientific Committee 46 on Operational Radiation Safety.
Serving on Scientific Committee 46-2 were:

Richard L. Doty, Chairman
Pennsylvania Power and Light Company
Allentown, Pennsylvania
Members
Albert J. Hazle
Arvada, Colorado

Noel Savignac
Albuquerque, New Mexico


iv

1

PREFACE

Charles E. Roessler
University of Florida
Gainesville, Florida

Edwin T. Still
Kerr-McGee Corporation
Oklahoma City, Oklahoma

Scientific Committee 46 Liaison Member

Keith Schiager
University of Utah
Salt Lake City, Utah
Serving on Scientific Committee 46 were:

Kenneth R. Kase, Chairman (1990Stanford Linear Accelerator Center
Stanford, California

)

Charles B. Meinhold, Chairman (1983-1990)
Brookhaven National Laboratory
Upton, New York
Members

Ernest A. Belvin (1983-1987)

Marietta, Georgia

David S. Myers (1987Lawrence Livermore
National Laboratory
Livermore, California

W. Robert Casey (1983-1989)
Brookhaven National Laboratory
Upton, New York

John W. Poston, Sr.
(1991- )
Texas A&M University
College Station, Texas

Robert J. Catlin (1983-1992)
University of Texas
Houston, Texas

Keith Schiager (1983University of Utah
Salt Lake City, Utah

Joyce P. Davis (1990- )
Defense Nuclear Facilities
Safety Board
Washington, D.C.
William R. Hendee (1983- )
Medical College of Wisconsin
Milwaukee, Wisconsin

)

)

Ralph H. Thomas
(1989- )
Lawrence Livermore
National Laboratory
Livermore, California
Robert G.Wissink
(1983- )
Minnesota Mining and
Manufacturing (3M) Center
St. Paul, Minnesota


PREFACE

James E. McLaughlin (1983- )
Santa Fe, New Mexico

1

V

Paul L. Ziemer (1983-1990)
U.S. Department of Energy
Washington, D.C.

Thomas D. Murphy (1983-1992)

U.S. Nuclear Regulatory
Commission
Washington, D.C.
NCRP Secretariat

James A. Spahn, Jr. (1986- )
Robert T. Wangemann (1986)
E. Ivan White (1983-1985)
The Council wishes to express its appreciation to the members of
the Committee for the time and effort devoted to the preparation of
this Report.
Charles B. Meinhold
President, NCRP
Bethesda, Maryland
August 1,1993


Contents
Preface .......................................................................................
1 Introduction .........................................................................
1.1 Purpose ............................................................................
1.2 Concepts of Radiation Protection ..................................
1.3 Scope of Report ...............................................................
2 Design of Radiation Protection Programs ...................
2.1 Criteria for Radiation Protection Programs .................
2.2 Program Management ...................................................
2.3 Radiation Safety Officer .................................................
2.4 Radiation Safety Committee .........................................
2.5 Preparation and Maintenance of Records ....................
2.6 Quality Assurance Program ........................................

2.7 Coordination Among Safety Programs .........................
3 Sources of Potential Radiation Exposures ...................
3.1 Source Characterization .................................................
3.1.1 Naturally Occurring Radioactive Materials ......
3.1.2 Distribution of Radioactivity in Ore. Product,
By-Products and Wastes ...................................
3.1.3 Characteristics Related to Radiation Dose ........
3.2 Occupational Exposures .................................................
3.2.1 External Radiation ...............................................
3.2.2 Airborne Radioactivity .......................................
3.2.3 Surface Contamination ........................................
3.3 Releases to the Environment ........................................
3.3.1 Airborne ................................................................
3.3.2 Waterborne ............................................................
3.3.3 External Radiation ...............................................
3.4 Process By-Products and Waste Materials ...................
4 Exposure Management Program ....................................
4.1 Exposure Limits .............................................................
4.2 Exposure Environment ..................................................
4.2.1 External Radiation ...............................................
4.2.2 Ore Dust ................................................................
4.2.3 Airborne Radon and Radon Progeny ..................
4.3 Facility Design and Engineering ..................................
4.3.1 Site Selection ........................................................
4.3.2 Facility Layout .....................................................
4.3.3 Equipment and System Design ...........................

.

.

.

.

vii


viii

I

CONTENTS

4.4 Facility Procedures and Practices .................................
4.4.1 Access Control ......................................................
4.4.2 Radioactive Material Control ..............................
4.4.2.1 Materials Handling .................................
4.4.2.2 Waste Management .................................
4.4.2.3 Sealed Source Control .............................
4.4.3 Personnel Protective Equipment ........................
4.4.3.1 Respiratory Protection ............................
4.4.3.2 Protective Clothing .................................
4.5 Employee Training .......................................................

5. Monitoring of Occupational Exposure .................................
5.1 Monitoring Objectives ....................................................
5.1.1 Characterization of the Workplace .....................
5.1.2 Personnel Exposure Assessment .........................
5.2 Monitoring Program .......................................................

5.3 External Radiation .........................................................
5.3.1 Characterization of the Workplace .....................
5.3.2 Personal Monitoring-External ..........................
5.4 Long-Lived Airborne Radionuclides .............................
5.4.1 Characterization of the Workplace .....................
.......
5.4.2 Personnel Exposure Assessment-Internal
5.5 Airborne Radon and Progeny .......................................
5.5.1 Characterization of the Workpla~e-~~~Rn
and

Progeny

..............................................................

5.5.2 Personnel Exposure Asse~sment-~~~Rn
and

Progeny

..............................................................

5.5.3 Radon-220 and Progeny .......................................
5.5.4 Monitoring for Control Purposes ........................

.

5.6 Surface Contamination ..................................................
5.6.1 Area Monitoring ...................................................
5.6.2 Monitoring of Personnel ......................................

5.6.3 Monitoring Other Items .......................................
5.7 Bioassay ..........................................................................
5.7.1 Bioassay Methods ...............................................
5.7.2 Bioassay Program Content ..................................
5.7.3 Routine Bioassay ..................................................
5.7.4 Post-Exposure and Follow-Up Measurements ...

6 Effluent Monitoring and Environmental

Surveillance

......................................................................

6.1 Environmental Pathways ..............................................
6.2 Effluent Monitoring ........................................................
6.2.1 Effluent Monitoring Objectives ...........................
6.2.2 Program Design ...................................................
6.2.3 Air Monitoring .....................................................
6.2.4 Water Monitoring .................................................


CONTENTS

.

1

6.3 Environmental Surveillance ..........................................
6.3.1 Environmental Monitoring Objectives ...............
6.3.2 Program Design ....................................................

6.3.3 Radon ....................................................................
6.3.4 Radon Progeny .....................................................
6.3.5 Long-Lived Airborne Radionuclides ...................
6.3.6 Soil and Vegetation ..............................................
6.3.7 Water .....................................................................
6.3.8 External Radiation ...............................................

7 Guidelines. Standards and Regulations ........................
7.1 General ............................................................................
7.2 Sources of Guidance and Standards ..............................
7.2.1 Scientific Recommendations ................................
7.2.2 Consensus Standards ...........................................
7.2.3 Federal Guidance and Policy ..............................
7.2.4 Rules and Regulations .........................................
7.3 Approaches to Radiation Limits ....................................
7.4 Occupational Exposures .................................................
7.4.1 Introduction ..........................................................
7.4.2 Recommendations .................................................
7.4.3 Standards and Regulations .................................
7.5 Effluents and the Environment .....................................
7.5.1 Emuents ................................................................
7.5.2 Wastes ...................................................................
7.5.3 Uranium and Thorium Processing Sites ............
7.5.4 Other .....................................................................
8 Radiation Emergency Response Planning ...................
8.1 General ............................................................................
8.2 Operations .......................................................................
8.3 Environment ...................................................................
8.4 Transportation ................................................................
9 Radiation Protection in Specific Applications ............

9.1 Introduction ....................................................................
9.2 Heap-Leach Extraction ..................................................
9.3 I n situ Mineral Extraction .............................................
9.4 Side-Stream Extractions of Uranium ...........................
9.4.1 Uranium Recovery from Phosphoric Acid ..........
9.4.2 Occupational Exposure Considerations ..............
9.4.3 Shipping and Transportation ..............................
9.4.4 Efluents and Environmental Monitoring ..........
9.4.5 Solid Radioactive Waste and Equipment Reuse

.

.

or Salvage

........................................................

9.5 Thorium and Rare-Earths Processing ..........................
9.6 Phosphate ........................................................................


X

1

CONTENTS
9.6.1 Mining. Beneficiation and Wet Rock

Handling

............................................................

9.6.1.1 Occupational Exposure ...........................
9.6.1.2 Mining and Beneficiation Wastes and

Post-Mining Land

................................
.......

9.6.1.3 Liquid Releases and Water Quality
9.6.2 Phosphate Rock Drying and Dry Rock

Handling

............................................................
...........................

9.6.2.1 Occupational Exposure
9.6.2.2 Emissions

.................................... .. .........

9.6.3 Wet-Process Phosphoric Acid Plants ...................
9.6.3.1 Occupational Exposure-Protection

Operations

............................................

9.6.3.2 Occupational Exposure-Clean-up

and
Maintenance ........................................
9.6.3.3 Occupational Exposure-Filter Pan
Repair ...................................................
9.6.3.4 Waste Management .................................
9.6.3.5 Phosphogypsum .......................................
9.6.4 Production of Phosphate Products ......................
9.6.5 Thermal Process (Elemental Phosphorus) .........
Appendix A Radioactive Serie~.~~'U. and ='U ......
Appendix B Conversion Factors ........................................
Glossary .....................................................................................
References .................................................................................
The NCRP .................................................................................
NCRP Publications .................................................................
Index ...........................................................................................

.

.


1. Introduction
1.1 Purpose

The National Council on Radiation Protection and Measurements
(NCRP) develops recommendations dealing with various aspects of
operational radiation protection. The basic principles and practices

of radiation safety are well established. However, specific facilities
present specific problems. To serve the needs of a particular facility,
effective programs should recognize and account for variables such
as the complexity of radiation exposure pathways and the magnitude
of potential radiation exposure a t a given facility. This Report
describes the vital parts of an effective radiation safety program
for mineral extraction facilities. It provides information useful for
choosing appropriate techniques of radiation control and monitoring
a t such facilities.
Because radioactive material occurs naturally throughout the
earth's crust, any mineral extraction operation or process, not just
those commonly perceived to be processing radioactive materials, is
a candidate for radiation safety measures. This Report draws on
examples from the uranium mining and milling industry, but principles and practices common across the entire mineral extraction
industry are emphasized.
Mining, milling and beneficiation have long been accepted technologies for extracting and processing ores. However, they are among
the technologies that have come under increasing scrutiny from
a society concerned about occupational and environmental risks.
Increasing awareness and attention has been placed on the potential
uses and risks of radioactive materials. Therefore, assessing the
radiation protection requirements and practices of the mineral
extraction industry is both timely and consistent with good work
practices.
This Report is written so that individuals with a basic technical
background can apply the concepts of radiation protection to evaluate
any mineral extraction operation. Management can use the Report
to define the degree to which radiation safety should be considered
in designing facilities and planning their operation. Design engineers as well a s health and safety professionals will find useful

2

/

1.

INTRODUCTION

information for applying the basic principles and practices of radiation safety to their specific facility's design and program. The reader
is not presumed to be thoroughly familiar with other radiation safety
literature. This Report addresses primary aspects of radiationprotection, but no single document can provide the solution to all problems
which may arise relating to radiation safety. References are provided
for those who wish to obtain more detailed information on specific
topics.

1.2 Concepts of Radiation Protection
Radiation protection programs are designed to allow society to
gain the benefits of using radioactive materials while minimizing
risk to the public and workers. In the case of mineral extraction,
the goal is to make sure that minerals can be extracted and processed
while keeping risks from radiation exposure to a minimum. The key
is to make sure exposures are evaluated and controlled effectively.
Most situations involving exposure to radioactive materials can
be managed easily because exposure to personnel can readily be
maintained well within established exposure limits; the radiation
risk is controlled using simple and inexpensive techniques. As exposure to personnel approaches the limit, however, more technically
complex and expensive controls need to be considered. One goal of
the radiation safety program is to make sure that both users and
the public are protected a t reasonable cost. Adequate protection
means that risk should, as far as possible, be limited to levels comparable with those experienced in other safe industries (NCRP, 1993).

The basis for controlling radiation-induced risk is drawn from the
many scientific studies which have been performed and which have
resulted in adoption of what is called the "linear no-threshold hypothesis." In simple terms, the assumption is that for any increase in
exposure, there is a corresponding increase in risk. Applying the
theory to real-life situations has its complications. Biological effects
that can be produced by radiation are also caused by other physical
and chemical agents and also occur naturally. Above-normal incidence of these effects (e.g.,several types of cancer) has been observed
in individuals exposed a t radiation levels greatly in excess of those
discussed in this Report as individual exposure "limits." To assess
the more common exposure situations, scientists extrapolate from
the number of observed effects a t high exposures to predict the number of presumed effects at lower exposures. The difficulty arises
primarily because, a t low exposures, there is a very low probability


1.3 SCOPE OF REPORT

/

3

that radiation-induced effects will occur. Further, any effects that
do occur are indistinguishable from those induced by other agents
and those normally seen frequently in any population. The assumption is made that effects will result from exposure of a population
to radiation and that the number of people affected, or the risk to a
specific individual, will be in direct proportion to the total radiation
exposure. This cautious assumption may overestimate risk but has
been adopted by the NCRP for purposes of radiation protection.
Because any radiation exposure is assumed to have an associated
risk, exposures are to be maintained at levels which are as low as
reasonably achievable (ALARA), economic and social factors being

taken into account. The inclusion of the word "reasonably" recognizes
both that the use of radioactive materials can yield benefits to society
and that exposure reduction often requires resource expenditures.
Achievement of exposure levels which are ALARA reflects the application of exposure reduction techniques until further reduction can
be attained only if the intended benefit would not be obtained or the
cost would be unreasonable. Exposure management to levels as low
as reasonably achievable is accomplished by controlling a number
of variables: the quantity of radioactive material, the location of
workers and the public relative to the material, the length of time
people are exposed to the material, the amount of material that
inadvertently escapes from processing streams, and the effluents
that contain radionuclides and are released to the environment.
An effective radiation safety program thus includes evaluation
of situations which may lead to radiation exposure, comparison of
expected exposures to exposure limits mandated by regulation, and
the application of control practices to maintain exposure at levels
which are ALARA.

1.3 Scope of Report

This Report describes the application of radiation safety concepts
to mining, milling and beneficiation facilities. The potential for radiation exposure differs in magnitude depending on the mineral and
the facility type. However, the same basic principles of radiation
safety should be applied to facility design and operations. For some
facilities, the application of these principles may mean the establishment of a radiation safety program because radiological protection
had not previously been considered relevant to the operation. Therefore, this Report emphasizes fundamental concepts, simplifiestechnical terminology and presents methods based on past experiences


4

1

1. INTRODUCTION

with mineral extraction. This Report will deal primarily with design
and operation. The decommissioning of facilities and reclaiming of
the facility site are beyond the scope of this Report.
Each section of this Report presents a piece of the total picture on
how to design and operate an effective radiation protection program.
In Section 2, organizational structures applicable to different program needs are discussed; while in Section 3, the characterization
of radiation sources and the potential pathways to individual exposure are addressed. In Section 4, management of radiation exposures
by facility design and in facility operations is described. Concepts
of monitoring occupational radiation exposure are considered in
Section 5, and the monitoring of potential exposures to the public
around a facility are described in Section 6. In Section 7, pertinent
regulations, standards and guidelines are presented. Emergency
planning concepts are addressed in Section 8. In Sections2 through 8,
concepts applicable to any mineral extraction facility are illustrated,
and guidelines are provided for program implementation. Uranium
extraction is specifically discussed to illustrate program elements
which can be applied to the exposure potential of specific mineral
extraction processes and to direct the reader to an appropriate level
of radiological control for those processes. In the last section of the
Report, Section 9, information is presented about radiation safety
practices for some specific extraction processes, such as phosphate
mining and processing operations.


2. Design of Radiation
protection Programs

2.1 Criteria for Radiation Protection Programs
Managers of mineral extraction facilities are responsible for ensuring that health, life, property and the environment are protected
during the conduct of operations. This requires a knowledge of the
particular types and levels of risk associated with their facilities. In
some cases, the predominant risk may be from common industrial
hazards; in others, from toxic materials. When exposure to radiation
or radioactive materials contributes to risk, consideration must be
given to radiation safety measures necessary to protect the health
and safety of employees and the general public.
The motivation to develop an effective radiation safety program
can come from several sources. For some processes, regulations mandate evaluating risks associated with naturally radioactive materials in ore and waste products. Other extraction processes are
unregulated (for purposes of radiation protection) but may result in
radiation exposure as ores are brought to the surface and processed.
Other motivators include corporate policy, the societal trend toward
litigation where exposure to a risk-producing agent is involved, and,
most important, concern for the health and welfare of both employees
and the public.
Whatever the motivation, there is a need for making responsible
decisions about the level of radiological control appropriate to a
given facility. In the process of developing a specific radiation safety
program, each of these motivators should be considered. The goal is
that outlined in Section 1.2: Evaluating facility operations with the
aim of reducing exposures to levels which are within established
limits and ALARA.
If this intent is met, several benefits may result, includingreduced
risk to individuals, improved worker morale, enhanced public and1
or regulatory agency perception of the facility, and reduced vulnerability to workmen's compensation claims or radiation-related
litigation.
For some facilities, exposure may be routinely so small that an
ongoing radiation safety program is unnecessary. Assessments such

6

1

2. DESIGN OF RADIATION PROTECTION PROGRAMS

as those described by Dixon (1984)may be useful in identifying those
facilities or processes for which the need for ongoing radiation safety
practices should be investigated further. As exposure to radiation
or radioactive materials becomes more frequent and as radiation
levels become more significant, the application of appropriate levels
of radiation protection controls is warranted. Based on the statement
in Section 1.2, the radiation safety program should be designed to
limit risks to employees and members of the public to levels comparable with risks from other common contributors to risk. For example,
the level of safety provided for employees should ensure an average
risk from radiation no greater than that from all sources of risk for
workers in "safe" industries (NCRP, 1993).

2.2 Program Management
Radiation safety programs will vary in staffing and structure,
depending on the degree of potential radiation exposure which has
been identified and the anticipated difficulty of controlling it. This
Section of the Report describes a decision chain useful for setting
up a radiation safety program appropriate to the needs of a given
facility.
Staffing demands will vary with the severity of the conditions a t
the facility. For example, if the projected exposure for any individual
is well below the annual exposure limit for a member of the public,

employing radiation specialists may be unnecessary. When t h e
potential exposure may approach or exceed this annual limit, consideration should be given to utilizing corporate staff or consultants to
evaluate conditions.
For those cases where potential exposures to some individuals are
anticipated to exceed the limits for members of the public, staffing
becomes a choice between a single organization responsible for both
industrial and radiological health and safety, or a qualified staff
dedicated solely to radiation protection. At some facilities the first
choice may be sufficient. At facilities requiring a more extensive
occupational (Section 5) or environmental (Section 6) monitoring
program, a dedicated staff may be warranted. Finally, where radiation exposure pathways are more complex or difficultto control, the
facility may need to designate a radiation safety officer and appoint
a radiation safety committee to review radiation safety issues and
recommend actions to senior management (NCRP, 1978a).That level
of need should rarely occur in the mineral extraction industry, and
when i t does, quantities of radioactive materials and potential


2.2 PROGRAMMANAGEMENT

1

7

exposures are likely to be large enough that some program structure
may be imposed by regulatory agencies.
Regardless of the size and configuration of a facility's radiation
safety organization, management retains the responsibility for
maintaining exposures within limits and ALARA. The safety organization's role is to provide technical support and equipment, so that
radiation protection practices and the concept of ALARA can be

applied most effectively. Optimal collaboration between management and the radiation organization must begin early. When radiation safety evaluations and criteria are applied as soon as possible
in facility planning, the facility is more likely to be designed and
operated in ways consistent with the objective of limiting exposures
in practical, cost-effective ways. When the size of potential radiation
exposures requires development of ongoing controls, management's
responsibility may extend for some period of time, even to the point
of providing maintenance and monitoring programs after facility
operations end.
Regardless of a radiation organization's specific structure, in order
to control exposure effectively its program should include several
features. Overall, this means that the authority and responsibility
for radiation protection should be allocated to the highest management level, then emphasized at all supervisory levels in proportion to
the amount of radiation exposure expected. The success of a program
depends primarily on management's clear commitment to radiation
safety. This level of commitment is expressed when management
provides adequate human and financial resources to implement programs successfully, instills in employees an awareness of their own
responsibility for safety, and evaluates program effectiveness on an
ongoing basis. In short, this means that management must apply
the same sound management principles to the task of producing an
effective safety program that it applies to producing ore or any other
end product.
In addition, program success depends on making workers aware
of the role they play in reducing unnecessary radiation exposures.
Specifically, they need to accept the importance of complying with
radiation safety rules and reporting potential problems, such as
malfunctioning equipment and procedural violations. Tools a r e
available for building this compliance: policy statements, training
programs and less formal communications, including the example
set by supervisors and managers. The training of individual workers
to be keenly aware of their own responsibility for radiation safety

is crucial to ensuring the effectiveness of any radiation protection
program.


8

1

2. DESIGN OF RADIATION PROTECTION PROGRAMS

2.3 Radiation Safety Officer
Employing a Radiation Safety Officer (RSO) is warranted for those
(few)mineral extraction facilities where exposure pathways are complex and difficult to control. At those facilities, the RSO should
supervise the radiation safety program, providing technical advice
as needed. To be fully effective, the RSO should report to senior
management and have the authority to enforce radiation safety regulations and administrative policies at all levels of the organization.
In addition, the RSO should be provided with adequate resources
and not be assigned duties which may lead to a conflict of interest
where radiation safety is concerned.
This level of authority does not, however, imply total responsibility. A radiation safety program is most effective only when everyone
involved in operating the facility is committed to the same objective
of reducing risk to a level which is ALARA. The RSO's responsibilities, therefore, also include guiding the operations groups so that
they consider measuring, evaluating and controlling radiological
conditions whenever they are performing either their ongoing activities or planned changes. To be effective,the RSO may need to develop
safety rules that are specific to that facility or organization.
The RSO should possess a combination of education, radiation
protection experience and appropriate training consistent with the
magnitude of potential radiation risk and the complexities of the
specific program. In some facilities, one person may appropriately
perform all the RSO and industrial hygiene or safety functions.

Other facilities, particularly those which must deal with more varied
sources of radiation, may require a t least one professional with more
specialized education and experience.

2.4 Radiation Safety Committee

In some cases, management should establish a radiation safety
committee to help define program scope and enhance their ability
to review a program's effectiveness. This committee may be set up
for any facility but is especially useful in those cases where potential
radiation exposures approach the dose limits. The RSO may work
with and be an ex-officio member of this committee, normally composed of several people aware of the facility's radiation protection
program and needs. For example, the committee might include
supervisors of maintenance, production and engineering. It should
review radiation safety analyses of operations and facility operating


2.5 PREPARATION AND MAINTENANCE OF RECORDS

/

9

procedures, assessing the need for increased management attention
to the radiation safety program. It may also review specific radiation
safety issues, providing advice on how to reduce radiation exposure,
and work on improving communications between employees and
facility management.

2.5 Preparation and Maintenance of Records

Systematic record keeping documents the extent to which the
radiation safety program has been implemented and provides a
means for determining how effective it has been in meeting its objectives. Specifically, this documentation demonstrates that potential
exposures have been evaluated and appropriate controls instituted.
Its value becomes apparent when questions are raised about how
well workers and the public have been protected from unwarranted
exposure and the assumed risks associated with that exposure.
To be effective, this record keeping should include certain basic
data. Records should describe both the radiological conditions found
a t the facility and the radiation doses received by workers. In addition, sufficient data should be maintained so that the environmental
impacts of the facility can be assessed. It should also be possible to
define patterns of radiation levels and exposures for the various
modes of the facility's operation. In setting up this records system,
management should consider the potential need for interpreting
and comparing data among similar types of facilities and against
established radiation protection standards and guidelines.
The extent of the record keeping system and the types of records
maintained vary with the complexity of the radiation safety program, the more complex the program (due to factors such as higher
potential exposures, multiple pathways of receiving exposureor multiple radiation sources),the larger the records system required. The
types of records which may be generated and retained include the
following:
(1) information on radiological conditions on the facility site,
a. radiation surveys,
b. surface contamination surveys,
c. airborne radionuclideconcentrations,usually for radon and1
or its progeny and for airborne particulate matter,
d. radioactive materials inventory and disposal;
(2) evaluations of radiation exposure of workers and visitors,
a. effective dose from external radiation and how it was
determined,

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2. DESIGN OF RADIATION PROTECTION PROGRAMS

b. committed effective dose from intake of radioactive materials (eg.,by inhalation) and how it was determined; in many
cases, the maintenance of individual records of duration
of exposure multiplied by corresponding concentration of
airborne radioactive material is appropriate,
c. bioassay data needed to estimate any uptake of radioactive
materials by personnel;
(3) evaluations of radiological impact on the environment,
a. radioactive emuents to the environment,
b. environmental modeling and/or monitoring; this may
include descriptions of meteorological, climatological and
hydrological data used in modeling and assessment efforts,
c. estimates of individual and collective doses to the public;
(4) program implementation documentation,
a. safety assessments of designs and operations; this may
include rationale regarding why extensive radiation control
measures were not necessary for the facility,
b. descriptions of unusual operational events involving the
potential for radiation exposure; this includes descriptions
of corrective actions and/or measures taken to prevent
recurrence,
c. standard operating procedures and relevant corporate
policies,

d. training course descriptions and rosters,
e. quality assurance data; for example, records on radiation
measuring instruments and their calibration.
Records should be dated to enable reconstruction of the radiation
safety program for any time period. Recommendations on the form,
content and retention of radiation program records are provided in
Report No. 114 (NCRP, 1992).
The length of time for retaining these records varies with the
document. Records of exposure of individuals may need to be maintained for a t least the lifetime of the individuals. When facility
operations are to be terminated, the need for continued retention of
records should be evaluated. Three criteria applicable to the evaluation should be applied:
(1) Will the records be needed for medical or legal reasons to
establish radiation exposure history for individuals?
(2) Will the records be needed for legal or administrative reasons
to establish the radiological conditions of the site? and
(3) Will t h e records be needed to document compliance with
regulations?
If these questions cannot be definitively answered, the prudent choice
may be to retain records until the uncertainties are resolved.


2.6 QUALITY ASSURANCE PROGRAM

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Facility management should consider compiling and publishing
the pertinent results of research, modeling and monitoring. This
assists the scientific community in its ongoing evaluations and communications of exposure and risk.

2.6 Quality Assurance Program

A quality assurance program for radiation safety is designed to
provide confidence among managers, workers and regulators that
the radiation safety program is meeting its objectives. The quality
assurance scope is broad, encompassing all the activities associated
with defining job scope, measuring job performance, and verifying
and documenting successful work completion. This means that high
quality programs demand high levels of commitment to quality in
every aspect of a program: facility design, operating plans and procedures, adherence to those plans and procedures, and verification and
documentation of that adherence.
When not only qualitative but also quantitative measurements
are required, precision and accuracy become prime objectives. Replicating and performing controlled tests of survey and measurement
techniques enhance the validity and credibility of results. Calibrations should be performed using sources traceable to the National
Institute of Standards and Technology (formerly the National
Bureau of Standards) or other recognized standards organizations.
In addition, radioanalytical laboratories should participate in a recognized inter-laboratory cross-check program (NCRP, 1991a).
Management should also make sure that any ongoing radiation
safety program is reviewed and audited periodically. Results of these
checks allow management to evaluate program effectiveness, define
improvementsthat will better control exposures, and track and document the ways these improvements are implemented. This close
surveillance should include the use of frequent inspections. During
these inspections, the facility's staff can observe operating practices
and review the need for corrective actions. Also, more formal reviews
should be conducted periodically, critically assessing pertinent data
from surveys and inspections, personnel exposure and training. To
get a clearer picture of the program's effectiveness relative to other
programs, data should be drawn not only from the facility itself, but
also from similar facilities. During these reviews, special attention

should be given to identifying temporal trends in results and equipment or procedural problems. These insights can then be used to
guide the development of appropriate program changes.


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2. DESIGN OF RADIATION PROTECTION PROGRAMS

In addition to conducting a variety of reviews, management should
consider including reviewers with differing training and experience.
Program effectiveness and record keeping should be assessed not
only by those directly responsible for the program but by outside
observers as well. The frequency will depend on the complexity of the
radiation safety program. Once the reviews are conducted, results
should be communicated to management at levels high enough in
the organization to make sure that appropriate follow-through will
take place, especially changes in operating practices, staffing levels,
training and commitment to radiation safety or resolution of other
program deficiencies which have been identified.

2.7 Coordination Among Safety Programs

A radiation safety program should be carefully coordinated with
the facility's overall safety program. After all, the programs share
the same purpose: To control risk so people will not suffer adverse
health effects or lose the ability to do their jobs. To accomplish that
purpose, radiation safety professionals use methods similar to those
of other health and safety professionals. This means that, when

appropriate to the types and levels of risk, the same people may
perform both radiation and other safety activities. In any case, the
radiation safety program should complement the other health and
safety programs.
Content for a specific program can be developed using four basic
approaches:
(1) consolidating data on risk;
(2) developing a perspective by comparing, for example, radiation
risks to other risks;
(3) defining an orderly process for assessing risk-benefit relationships; and
(4) creating a means to perform those tasks effectively (NCRP,
1980a).
In some cases, defining an appropriate control program should
include efforts to evaluate separate components of risk simultaneously. For example, in evaluating the control needed for airborne
uranium ore dust, exposure to uranium and silica must both be
considered. Similarly, in evaluating the risk associated with splashing of some solutions, both the pH and the concentrations of radionuclides and their decay products must be addressed. Cases may arise
which call for protective measures for radiological purposes that
differ from, or even potentially compete with, those warranted to


2.7 COORDINATION AMONG SAFETY PROGRAMS

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mitigate nonradiological risks. In those rare cases, maximal protection against overall risk should be provided. Radiation and other
health and safety professionals should work together, assessing the
combined risks along with costs of control, then determining appropriate action (IAEA, 1987). Cooperation is imperative in two areas
of risk control: demonstrating management commitment to safety

and instilling in employees an awareness of their own responsibility
for safety.
Just as development of a total radiation safety program depends
on assessing the impact of specific conditions, medical surveillance,
based on the general principles of occupational medicine, should
take into account specificworking conditionsand the potential radiation and other risk factors at the particular work site (ICRP, 1986).


3. Sources of Potential
Radiation Exposures
The design and implementation of radiation protection controls
in mineral extraction are influenced by a variety of factors,including
ore1 type, ore distribution and quality, mining method, extraction
process, land use characteristics, geology and hydrology, and the
radiation situation. The discussion of the natural radiation environment in this Section brings forth an awareness of the potential
for radiation exposure for any extraction operation or process. The
following discussions of potential pathways to individual exposure
(Sections 3.2, 3.3 and 3.4) help relate the existence of naturally
radioactive materials in the workplace to those locations and operations for which radiation control practices may be appropriate.

3.1 Source Characterization
3.1.1 Naturally Occurring Radioactive Materials

Naturally occurring radioactive materials of concern in the mineral extraction industry are predominantly associated with the 238U
(uranium) and 232Th(thorium)radioactive decay series. These radioactive decay series are described in Appendix A.
A thorough description of natural radioactivity is found in NCRP
Report No. 94 (NCRP, 1988a). From the contents of that report, it
can be seen that the abundance of uranium and thorium varies
widely over geographic areas. Igneous and sedimentary rocks on
average contain concentrations on the order of 0.5 to 5 mg per kg

(conventionally)of 238Uand 2 to 20 mg per kg of 232Th.These correspond to radionuclide concentrations of about 6 to 60 Bq per kg of
'The word "ore"in this Report may refer to either a natural combination of minerals
from which an extraction is to occur or a technologically altered combination of
minerals from which additional extraction is to occur. An example of the latter type
of operation may be the extraction of tin from a slag residue resulting from a previous
processing operation.


3.1 SOURCECHARACTERIZATION

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15

238Uand 8 to 80 Bq per kg of 232Th.In the absence of chemical or
physical separation processes, an equilibrium is reached in which
the number of atoms of each nuclide of a radioactive series that
decays during a specific time interval nearly equals the number of
decays of the parent nuclide in the series. The activity of each member of the uranium series, for example, would therefore be about 6
to 60 Bq per kg in rock.
Chemical and physical separation are common, however, primarily due to mechanical processes and the effects of water movement
through the rock. These processes lead to the relative depletion of
some nuclides from certain rocks and soils and the relative concentration of others. While such concentration and depletion processes
create the potential for economical extraction of some minerals, they
also result in widely varying radionuclide concentrations over ore
types and locations.
In the mining and milling industry, personnel extract a mineral
which is relatively concentrated.In the process, they may contact and
receive radiation exposures from nuclides of the naturally occurring
radioactive series. The magnitude of exposure depends on the characteristics of the specific mineral strata and the extraction processes.

Examples of naturally occurring radioactive materials in mineral
resources are listed in Table 3.1 (Gesell and Prichard, 1975; Gesell
et al., 1977; CRCPD, 1981; NCRP, 1988b; Drummond et al., 1990;
IAEA, 1990; EPA, 1991; Johnston, 1991; Pinnock, 1991). The list
should not be considered all-inclusive. For example, exposures have
been attributed also to smelters processing lead and zinc (NCRP,
1987a) and may occur in the extraction of virtually any mineral.
In mines, sources of radiation exposures may include external
gamma radiation and airborne radon, radon-decay products (progeny) and ore dust containing radionuclides. Radon and its shortlived progeny often constitute the most important potential exposure
source, but the long-lived alpha-emitting materials in ore dust are
also of concern. The ingestion of radioactive materials and exposure
to external gamma radiation warrant consideration but generally
are of less significance (IAEA, 1976a; ICRP, 1977; 1981).
Sources of exposure during the extractive processes are similar
to those in the mine environment. However, milling can result in
elevated concentrations of various radionuclides at different stages
of the process. Consequently, the potential for exposure to airborne
radionuclides and to external gamma radiation can be increased
relative to that experienced in the mines (IAEA, 1976a).
The uranium and thorium series are also associated with petroleum and natural gas deposits. Consequently, 222Rnmay be present
in natural gas, and 'lOPb and 210Pomay be present in condensed


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3. SOURCES OF POTENTIAL RADIATION EXPOSURES

TABLE3.1-Natumlly occumng mdioaetivity related to mineml resources.

Mineral
Mineral or waste radioactivity
Aluminum
0.25 Bq Ulg ore
0.1-0.4 Bq Ralg (bauxitic limestone, soil)
0.03-0.13 Bq W g (bauxitic limestone, soil)
0.7-1 Bq Ralg (tailings)
0.03-100 + Bq U/g ore
0.02-0.11 Bq W g ore
Fluorspar
Uranium series
4 Bq Ralg (tailings)
Iron
Uranium series
Thorium series
Uranium series (tailings)
Molybdenum
Monazite
6-20 Bq U/g sands
Thorium series (4% by weight)
Natural gas
2-17,000 Bq Rn/m3 (gas, average for groups of U.S. and
Canadian wells)
0.4-54,000 Bq Rdm3 (gas, individual U.S. and Canadian
wells)
0.1-50 Bq 21?Pb,2'0Po/g(scale, residue in pumps, vessels,
and residual gas pipelines)
Uranium series
Niobium
(columbium)Thorium series

tantalum
Oil
Bq RaIL, ranging from mBq to 100 BqIL (brines or produced
water)
Bq Ralg, ranging up to 70 Bqlg (sludges)
Bq to tens of Bq Ralg, ranging up to 4,000 Bqlg (scales)
100-4,000 mBq U naturallg ore
Phosphate
15-150 mBq Th naturallg ore
0.6-3 Bq Ra/g ore
Thorium series
Potash
Potassium-40
Uranium series
Rare earths
Thorium series
Tin
1-2 Bq Ra/g (ore and slag)
30-750 mBq Ulg ore
Titanium
35-750 mBq Thlg ore
15 Bq Ra/g (ore)
Uranium
100 Bq Ralg (slimes)
10-20 Bq Ralg (tailings)
Vanadium
Uranium series
Uranium series
Zinc
Thorium series

4 Bq U/g sands
Zirconium
0.6 Bq Thlg sands
4-7 Bq Ralg sands