United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/540/2-88/002
August 1988
Superfund
Technological
Approaches to the
Cleanup of
Radiologically
Contaminated
Superfund Sites

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                                     EPA/540/2-88/002
                                       August 1988
    Technological Approaches to the
Cleanup of Radiologically Contaminated
             Superfund Sites
            U.S. Environmental Protection Agency
                Washington, D.C. 20460
                               Agency

                               167Q
              Cnicago, 1L  50604

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                                  Notice
This document  has been  reviewed  in  accordance  with the  U.S.  Environmental
Protection Agency's  peer  and  administrative  review  policies and  approved  for
presentation and publication. Mention of trade names or commercial products does  not
constitute endorsement or recommendation for use.

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                                  Abstract
This report identifies  technologies  that may  be useful in removing  or stabilizing
radiological contamination at those uncontrolled hazardous waste (Superfund) sites that
contain  radionuclides.  The radioactive materials at  some Superfund  sites  consist
primarily of waste  from radium, uranium, and thorium processing.  Twenty  existing
Superfund  sites are known  to contain  radionuclides,  along  with seventy-one sites
managed  by  the  Department of Energy.  This report addresses  remediation  of
contaminated  soils;  it  does  not address  remediation  of  contaminated  buildings  or
ground  water. This report is  not intended to  provide any legal  or policy basis for the
selection or use of technology for cleanup of a hazardous waste site.

Sites contaminated with radionuclides pose a  unique problem because,  unlike organic
wastes,  radionuclides cannot  be destroyed by physical or  chemical means; they can
only decay through their  natural process.  Thus, alteration  or remediation of  the
radioactive decay processes,  thereby changing the fundamental  hazard, is not possible.
Several  technologies have potential for  eliminating  or stabilizing  radionuclides  at
radiologically  contaminated sites.  These  include both  on-site  and off-site disposal,
on-site  treatment,  radon  control,  chemical  extraction,  physical separation,  and
combined physical separation and chemical  extraction  technologies.  Applicability  of
these technologies is  controlled  by  site-specific factors, so their suitability must be
determined on a  site-by-site basis.

Issues  of  significant  concern in  attempting  to  apply  remedial techniques  include
disposal siting, handling of concentrated residuals, public reaction, and cost.

Many of the technologies have not been satisfactorily demonstrated. There is a need
for  additional  assessment  studies.  Significant research and  development activities,
including bench-scale  and  pilot-scale studies,  would  be necessary prior to full-scale
mobilization  for  site  cleanups.  These technologies should  be  evaluated  for
implementation as  they  may have  the  potential for significantly improving cleanup
efforts.

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                                          Contents
Abstract   	    iii
Figures  	   vii
Tables   	    ix
Acknowledgments   	    x
Executive Summary  	     xi

      1.   Introduction   	    1
          1.1   Study Purpose and Objectives  	    1
          1.2   Health Concerns  	    1
          1.3   Waste Sources and Contaminated Media   	    3
          1.4   Scope of Report   	    3
          1.5   References   	    4

      2.   Disposal   	    5
          2.1   Introduction   	    5
          2.2   On-Site Disposal   	    5
               2.2.1 Capping  	    5
               2.2.2 Vertical Barriers	    7
          2.3   Off-Site Disposal   	    8
               2.3.1 Land Encapsulation  	    8
               2.3.2 Land Spreading  	    9
               2.3.3 Underground Mine Disposal   	    10
               2.3.4 Ocean Disposal  	    11
          2.4   Typical Costs of Disposal 	    12
          2.5   References   	    13

      3.   On-Site Treatment   	    15
          3.1   Introduction   	    15
          3.2   Technologies of Potential Interest  	    15
               3.2.1 Stabilization or Solidification   	    15
               3.2.2 Vitrification   	    17
          3.3   Typical Costs of On-Site Treatment Technologies    	    18
          3.4   References   	    18

      4.   Radon Control  	    19
          4.1   Introduction   	    19
          4.2   Methods	    19
               4.2.1 Radon Control and Reduction in Buildings   	    19
               4.2.2 Electrostatic Precipitators  	    20
               4.2.3 Soil Gas Venting and Areal Control  	    20
          4.3   Typical  Costs of Radon Control   	    24
          4.4   References   	    25

      5.   Chemical Extraction  	    27
          5.1   Purpose  	    27
          5.2   State of the Art  	    27

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                              Contents (continued)
     5.3   Technologies of Potential Interest  	   27
          5.3.1  Extraction with Water 	   28
          5.3.2  Extraction with Inorganic Salts  	   29
          5.3.3  Extraction with Mineral Acids  	   30
          5.3.4  Extraction with Complexing Agents  	   32
          5.3.5  Technologies  for Separating Radionuclides from Extractant  	   33
     5.4   Typical Costs of Chemical Extraction Technologies   	   36
     5.5   References  	   37

 6.   Physical Separation Processes   	   41
     6.1   Purpose  	   41
     6.2   State of the Art  	   41
     6.3   Technologies of Potential Interest  	   42
          6.3.1  Screening 	   43
          6.3.2  Classification  	   44
          6.3.3  Flotation  	   51
          6.3.4  Gravity Separation  	   53
          6.3.5  Support Technologies for Treatment of Liquid Recycle  	   54
     6.4   Typical Costs of Physical Separation Technologies   	   57
     6.5   References  	   58

 7.   Combined Physical Separation and Chemical Extraction Processes  	   61
     7.1   Purpose and Mode of Operation  	;   61
     7.2   State of the Art  	   61
     7.3   Technologies of Potential Interest  	   61
          7.3.1  Soil Washing  and Physical Separation  	   61
          7.3.2  Separation and Chemical Extraction   	   63
          7.3.3  Separation, Washing and Extraction   	   64
     7.4   Typical Costs of Separation and Extraction Technologies  	   65
     7.5   References  	   66

 8.   General Issues at Radiologically Contaminated Superfund Sites   	   67

 9.   Criteria for Further Studies  	   71

10.   Conclusions  	   73
     Appendices
     A.   Applicable Laws, Regulations, and  Guidance  	   75
             Addendum I   Combined NRC-EPA Siting Guidelines for Disposal of
              Commercial Mixed Low-Level Radioactive and Hazardous Wastes    	   77
             Addendum II  Joint NRC-EPA Guidance on a Conceptual Design
              Approach for Commercial Mixed Low-Level Radioactive and
              Hazardous Waste Disposal Facilities	   80
     B.   Characteristics of Man-Made Radiologically
                 Contaminated Sites  	   85
          Radiologically Contaminated Superfund Sites	   85
          Department of Energy  Remediation Programs  	   97

     Bibliography  	    103
     Abbreviations and Symbols  	    112
     Conversions  	    113
     Key Chemical Elements   	    114
     Glossary  	    115
                                          VI

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                                           Figures
Number                                                                                 Page

 1      Uranium-238 decay series   	   2
 2      Schematic of a cover profile  	   6
 3      Slurry trench construction operations  	   7
 4      Grout curtain around waste site  	   7
 5      Schematic of a land encapsulation system  	   9
 6      Conceptual view of a mine storage facility  	    11
 7      Subsurface injection machine   	    16
 8      In situ vitrification process   	    17
 9      Tile ventilation where tile drains to sump  	    21
10      Sub-slab ventilation    	    22
11      Gas extraction well for landfill gas control  	    23
12      Schematic diagram of a forced air venting system  	    24
13      Pilot-scale equipment test for soil decontamination    	    43
14      Typical  separation sizes of the basic screen types 	    45
15      The basic screen types  and their classifications	    46
16      Hydrocyclone 	    51
17      Schematic of a shaking  table, showing the distribution of products   	    53
18      Limits of water content variation  	    54
19      Conceptual soil decontamination process flow sheet   	    62
20      Simplified process flow diagram of the EPA soil washer  	    65

A1      Mixed waste disposal facility  	    81
A2      Double  liner and leachate collection system   	    81
A3      Cross-sectional view A-A    	    82
A4      Waste cover system  	    83
B1      FUSRAP sites as of 1982   	    98
B2      Locations of UMTRAP sites 	   100
                                              VII

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                                          Tables
Number                                                                                Page

 A      State of the Art of Remediation Technologies  	   x

 1      Typical Background Radiation Levels  	   3
 2      State of the Art of Disposal Methods  	   6
 3      Ocean-Disposed Low-Level Radioactive Waste, 1946-1970      	   12
 4      Typical Costs of Various Disposal Methods  	   13
 5      State of the Art of On-Site Treatment Technologies   	   16
 6      Typical Costs of On-Site Treatment Technologies    	   18
 7      State of the Art of Radon Control Technologies 	   19
 8      Representative Exposure to Radon-222 Progeny   	   20
 9      Typical Costs of Various Radon Reduction Techniques in Existing Homes  	   25
10      State of the Art of Chemical Extraction Technologies  	   28
11      Physical Separation Technology and Particle Size   	   42
12      State of the Art of Physical Separation Technologies  	   43
13      The Major Types of Screens   	   47
14      Types of Screening Operations and Equipment  	   48
15      The Major Types of Classifiers	   49
16      Typical Costs of Major Physical Separation Equipment 	   58
17      State of the Art of Combined  Physical Separation and
            Chemical Extraction Technologies  	   62
18      Soil Product Plutonium Level  from  Pilot Plant Operation 	   62
19      Site and Waste Characteristics that Impact Remediation Technologies  	   71

B1      Radioactive Waste Superfund Sites  	   86
                                             IX

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                            Acknowledgments
This report was prepared under the overall direction  and coordination of Paul  S.
Shapiro, Program Manager in the Office of Environmental Engineering and Technology
Demonstration  (OEETD)  of  EPA's  Office of  Research  and  Development.  The
introduction,  the appendix  on  radiologically contaminated  sites, and  the chapters on
disposal methods and radon control were  prepared by Robert Hartley  assisted by  Adib
Tabri of the OEETD Risk Reduction Engineering Laboratory  (RREL) in Cincinnati. The
chapters on chemical extraction, physical separation, and combined physical separation
and chemical extraction  processes were prepared by Ramjee Raghavan  and Gopal
Gupta of Enviresponse,  Inc., who  compiled the  report as a whole.  The chapter on
chemical extraction and  physical  separation was prepared using information  from
"Review of  Chemical Extraction and Volume Reduction  Methods for  Removing
Radionuclides from Contaminated Tailings and  Soils for Remedial Action," by William
S.  Richardson,  Gary  B.  Snodgrass, and  James  Neiheisel,  Analyses  and Support
Division and  the Eastern Environmental Radiation Facility, Office of Radiation Programs
(ORP), July 24, 1987.  Additional information was  provided by William Gunter of ORP.
Frank Freestone and Darlene Williams of the RREL Edison, New Jersey,  facility  were
Project  Officers for Enviresponse.  Acknowledgments are also  due to  the  word
processing and editorial staff.

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                                       Executive Summary
Introduction

This document identifies potential  technologies that
possibly can be applied in the control and remediation
of radioactive contamination  at Superfund sites. This
report  provides a discussion of  the technologies;  it
does not give a detailed critical  evaluation  of  them.
The report does  not  include in-depth analyses that
would be needed  to determine the applicability of any
of these technologies at a particular site.

The report only addresses treatment and  disposal of
radiologically contaminated soils, and radon control.  It
does not  address,  for  example,  remediation  of
radiologically contaminated buildings. The report also
does  not  address  treatment  of  radiologically
contaminated ground  water,  which is  of  concern at
some Superfund sites.

The radioactive materials at many Superfund sites are
by-products  of  uranium,  thorium,  and  radium
processing in  the  form of  tailings,  contaminated
buildings and equipment, and stream sediments.

The primary public health threats from the radioactive
materials are through inhalation of radon and  radon
progeny, external  whole body exposure  to gamma
radiation, and ingestion of radionuclides through food
and  water.   Radon  and   radon  progeny are
continuously  produced through the  decay and
decomposition of  uranium,  thorium,  and  radium.
These hazards will persist  throughout  the  entire
decay  time if  no remedial  action is  taken. These
hazards could include the increased risk of cancers in
the exposed whole body and may also increase the
risk of genetic damage that may continue  to  cause
inheritable defects in future generations.

It should be noted that the  radioactive contaminants
are not  altered  or  destroyed by  treatment
technologies. The volume of contaminated  material
may  be  reduced,  but the  concentration of  the
contaminants  will  be much  higher in  the  reduced
volume.  Some type of containment and/or  burial  is
the only ultimate  remedy for materials  contaminated
at levels above those considered safe for exposure.

Table A on the following page shows the  state  of the
art of  the various disposal,  on-site treatment,  radon
control, chemical extraction, physical separation, and
combined physical separation and chemical extraction
technologies that are discussed in this report. Since
none  of the  chemical extraction  and physical
separation  technologies has  been used in a  site
remediation situation,  their  application must  be
approached cautiously.

Significant research and development activities would
be necessary prior to full-scale mobilization  for site
cleanup.  The same  holds  true for solidification or
stabilization  processes.  Only excavation and  land
encapsulation  have  been  used to   remediate
radiologically contaminated sites; ocean disposal has
been  used  for  disposal  of  low  level   radioactive
wastes.

Remediation Sites

Twenty  sites  that  contain  man-made   radioactive
wastes are on or are proposed for inclusion on the
National Priorities List (NPL).  These Superfund sites
are described briefly in  Appendix B of this document.
(Information  provided  is  accurate  as  of December
1987.)  The sites  contain  tailings  piles   and
redistributed tailings,  solid waste landfills, hazardous
waste landfills, fabrication plants and laboratories, and
contaminated ground  water.  Remedial  investigation
and feasibility studies (RI/FS) have been completed
on  eight sites and are  underway on  seven sites.
Remediation at  none  of  these  sites  has  been
completed.  However,  the Department  of  Energy
(DOE) has  completed  remedial  actions at  vicinity
properties associated with DOE NPL sites.

The DOE cleanup projects, which  also are described
in Appendix B,  mainly  stem from DOE's  inherited
responsibilities  in the  area  of  nuclear materials
production. DOE  has four major cleanup projects:

    (1) Formerly  Utilized Sites  Remedial  Action
       Project (FUSRAP) - 29 sites;
    (2) Uranium  Mill Tailings Remedial Action Project
       (UMTRAP) -  24 sites;
    (3) Grand Junction  Remedial  Action  Project
       (GJRAP) - 1  site; and
    (4) Surplus  Facilities Management Program
       (SFMP) - 17 sites.
                                                  XI

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Table A. State of the Art of Remediation Technologies
                                                                 Field
Technology
On-site Disposal
Capping
Vertical barriers
Off-site Disposal
Land encapsulation
Land spreading
Underground mine disposal
Ocean disposal
On -site Treatment
Stabilization or solidification
Vitrification
Radon Control
In homes
- ESP
Areal control
Chemical Extraction
With water
With inorganic salts
With mineral acid
With complexing agents
Demonstration
Bench Pilot with
Laboratory Scale Scale Radioactive
Testing Testing Testing Material
X
X
X
X
X
X X
X X
X X
X X
X X
X X
x xxx (from ores)
x xxx (from ores)
Radiologically
Contaminated
Site
Remediation Remarks
x
x
Land spreading of low-level radium sludge
from drinking water is an allowed policy in
Illinois
DOE currently working on mined repository
for radioactive waste
Stringent regulations for radioactive waste
Proposed by DOE for low-level radioactive
waste
Field testing by ORNL
x As a temporary and interim measure
Used in extraction of radium, thorium, and/or
uranium
Used in extraction of uranium
     Screening

     Classification

     Gravity concentration

     Flotation
x     x (from ores)

x     x (from ores)

x     x (from ores)

x     x (from ores)
Used m extraction of radium, thorium, and/or
uranium

Used in extraction of radium, thorium, and/or
uranium
Used in extraction of radium, thorium, and/or
uranium

Used in extraction of radium, thorium, and/or
uranium
Combined physical separation
and chemical extraction
    Soil washing and physical
    separation
    Separation and chemical
    extraction
     Separation, washing,  and
     extraction
                                 Pilot-plant development and testing needed
                                 for radioactive wastes

                                 Various portions of the process have been
                                 developed for extraction of uranium from
                                 ores. Pilot-plant testing and development
                                 needed for radioactive waste
                                 Significant bench-scale and pilot-plant
                                 testing needed for radioactive waste
                                                              XII

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Current DOE  projects also involve  the  cleanup of
thousands of vicinity properties,  about  4000 in
GJRAP alone. The  Grand Junction Remedial Action
Project has  excavated  and  moved contaminated
material to an  interim storage site from approximately
700 vicinity  sites  and  is  currently   evaluating
alternatives for remediation of the interim storage site.
To  date, seven sites administrated by DOE under the
FUSRAP project have been remediated. Three of the
FUSRAP  sites are  also  on  the NPL.  The SFMP
includes over 30 currently active projects. Two of the
SFMP  sites are on the NPL.

In addition, DOE's Office of Defense Programs (OOP)
has a  program  similar to SFMP for  its  sites. OOP
conducts selected remedial decontamination activities
as required at facilities under their jurisdiction.

In  most remedial actions  conducted to  date,  the
radioactively  contaminated  material  has  been
excavated and  contained  in  either  permanent or
temporary above-ground containment  facilities.
These  facilities  have been designed   to  include
perimeter air  monitoring,  surface water  runoff
collection  and  containment  features, and ground
water monitoring devices.

All  methods used to accomplish remedial  action on a
site contaminated with radionuclides will  result in
waste  materials that require disposal  or storage.  The
final disposal of  these waste materials is the single
largest problem in remedial action.

Some  of the Superfund sites contain various types of
hazardous wastes,  and the radioactive  portion  may
pose a relatively minor  problem.  The presence of
other   hazardous   materials  may complicate
remediation of the  radioactive  portion of  the waste
and vice-versa.

Section 121  of  CERCLA mandates  that remedies
must be protective,  utilize a permanent  solution  and
alternative  treatment technologies or  resource
recovery options to  the maximum extent  practicable,
and be cost effective. In  addition, cleanup standards
for  remedial  actions must meet any applicable or
relevant and appropriate requirements (ARARs).

Standards developed  under  Section 275 of  the
Atomic Energy Act  and Section 206  of the Uranium
Mill Tailings Radiation Control Act (UMTRCA) of 1978
may be applicable or relevant and appropriate on  a
site-specific  basis to  the cleanup of radiologically
contaminated Superfund sites. The EPA  promulgated
40  CFR 192,  Health  and  Environmental  Protection
Standards for  Uranium Mill Tailings in January 1983
under authority of these Acts. The pertinent standards
are contained in  40  CFR  192.12, 192.32,  and 192.41,
and deal with the acceptable levels of radioactivity in
residual materials and radiation  emission  levels from
them,  and with disposal  requirements. The disposal
requirements include a  design  life  of  at  least 200
years, and preferably 1,000 years where the latter is
reasonably  achievable.   However,  standards are
applicable to uranium mill tailings only. Relevance and
appropriateness  must  be  determined  according  to
specific site conditions.


Disposal
Disposal can be in one  of  two categories:  on-site
disposal or off-site  disposal.  Applicability  of  these
methods to Superfund sites  is  controlled  by  site-
specific factors;  therefore, their usefulness must be
determined  on  a  site-by-site  basis.


On-Site Disposal

Two  methods  are  available for on-site  disposal.
These may be applied in situ. They are:

        Capping

        Vertical barriers

Capping is simply covering the contaminated site with
a  thick layer  of low-permeability soil.  The  design
would be  chosen  to: (1) attenuate  the  gamma
radiation associated with all the radionuclides present,
(2)  protect  the  ground  water and  3)  provide
reasonable  assurance  that release  of radon from
residual radioactive  material  to  the  atmosphere will
not  exceed  acceptable  limits.  Capping  has the
advantages of relatively low cost, ease of application,
and  having  been used for remediating  radiologically
contaminated sites.

Capping has certain  drawbacks.  It does  not eliminate
the source of radioactivity; this  limits further  use  of
the site. The cap must be  maintained as long as the
contaminant exists  at  the  site.  A cap  must  not be
penetrated for construction  or installation of  structures
and  utility  hardware. Therefore,  existing  structures
must be  removed  before  capping.  Also,  horizontal
migration of the  radionuclides  in  ground water could
still occur.

Vertical subsurface barriers (barrier walls) could serve
as barriers  to horizontal migration of  radionuclides,
but  perhaps more  important,  as  barriers   to the
horizontal  movement of  ground  water  that may be
contaminated with  radionuclides. Vertical barriers are
relatively simple  to install. They  perhaps could serve
as the  container  walls  for  extraction  techniques.
Disadvantages include  the  difficulty of obtaining truly
low  permeability  and  the possibility  of material
incompatibility  with  waste  chemicals.  Before
attempting  the installation of a barrier  wall, detailed
data  are  required  on  the physical and  chemical
characteristics of the soil.
                                                  XIII

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Off-Site  Disposal

Off-site disposal can  be  considered  for  either
temporary  storage  or  permanent  disposal.  The
purpose would be to limit the exposure of people and
the environment to the radionuclide. This method can
be applied to both untreated materials and materials
that have been modified through a volume reduction
process. The waste materials could be treated before
disposal to reduce their volume or to stabilize them
so that they  may be  transported more  easily. Four
off-site disposal methods are briefly described in this
report:
       Land encapsulation
       Land spreading
       Underground mine disposal
    -   Ocean disposal

Land  encapsulation, either  permanent or temporary,
has been the disposal  method most  used so far for
low-level  radioactive waste  materials.  Land
encapsulation on site can also occur, but this may not
be applicable in all situations. It can be as simple as
excavating  the contaminated material  and,  without
further treatment,  hauling it  to a secure site designed
for  land  encapsulation. The  containment structure
technology  has been used to remediate radiologically
contaminated  sites. This technology  was originally
developed for the disposal of hazardous wastes.

Joint  NRC-EPA Design Guidelines  and Combined
NRC-EPA  Siting  Guidelines  for  Disposal  of
Commercial Mixed  Low-Level  Radioactive  and
Hazardous  Waste   provide  guidance on land
encapsulation  siting  and  design where chemical
contamination is also a problem (see Appendix A).

Selecting a site for a new facility or finding an existing
site that will accept the waste can be very difficult. In
addition,  the problems  of  handling  and  transporting
the waste  must  be considered.  If  the  radioactive
portion is first concentrated, as in  chemical extraction
and physical  separation, additional  disposal  issues
could result due to higher levels of radioactivity in the
concentrated   waste.   Advantages  of  land
encapsulation include  the  relative  maturity  of  the
technology,  the complete removal of the waste from
the affected  site, and the relative  simplicity of the
prerequisite information needs.

Land  spreading  is  a  technology  that has been
considered  for radiologically contaminated  wastes.
This   technology  involves  excavation  of  the
contaminated  material,  transporting  it  to a  suitable
site,  and spreading it on unused land, assuring that
radioactivity levels approach  the  natural  background
level   of these  materials  when the  operation is
completed.

Land  spreading might be  more appropriate  for  dry,
granular  tailings and soils.  It would likely  be
inappropriate  for  materials contaminated  with both
radioactive and  nonradioactive  hazardous wastes.
Another similar method is blending with  clean soil
prior to land spreading.

Underground  mine disposal could provide secure and
remote containment. Disposal in underground  mines,
either  new  or  existing,  could  be  costly.  The
radiologically  contaminated waste could be excavated
and  transported  without treatment to the  mine  site.
Alternatively,  it  could  be  pretreated  for volume
reduction  or  solidified to  facilitate transport  and
placement.

There  would be  a  tradeoff  between  costs  for
treatment  or solidification and costs for transportation
and  placement. Transportation costs and  associated
risks need to be  researched further.  Movement  of
radionuclides into ground  water  must be considered
and prevented.

Ocean disposal  could  be  an   alternative  to land-
based  disposal options. This alternative should  only
be evaluated  for low level mill tailing wastes and not
considered for enhanced  radioactive materials  or
concentrated  residuals.


On-Site  Treatment
Two methods are  available  for treating radiologically
contaminated  wastes  so  that  the  radioactive
contaminants may be immobilized. These are:

       Stabilization or solidification
       Vitrification

Stabilization or solidification immobilizes radionuclides
(and could reduce radon emanation) by trapping them
in an  impervious  matrix.  The   solidification agent
for  example, Portland  cement,  silica  grout,  or
chemical  grout-can  be  injected directly  into  the
waste  mass  or the waste can be excavated,  mixed,
and  replaced. It offers  the  opportunity to  leave the
waste materials on site in an immobilized state. It may
be used as additional security for a waste  mass that
will  be capped. The presence  of other  hazardous
chemicals  could  interfere with  some  solidification
processes.  Although the  radionuclides  are  not
removed in this process, their mobility and spread in
the environment are restrained.

Vitrification is another process  that  can  immobilize
radioactive contaminants by  trapping them in  an
impervious matrix.  The  in  situ process  melts  the
waste  materials between two  or more  electrodes,
using large amounts of electricity while doing so. The
melted material then cools to a glassy mass in which
the radionuclides are trapped.

Volatilization  of waste substances must be contended
with;  some  of  the  volatiles  may be  vaporized
                                                  XIV

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radionuclides. Excavation and vitrification in  a plant
designed for the purpose can  be  done  using  an
electric furnace or a rotary kiln,  but dealing with the
resulting solids  may  pose  additional  problems.
Vitrification  is very energy-intensive.


Radon Control Without Source
Remediation
As  an interim  measure, it  may  be  possible to
remediate  on-site properties  through radon removal
techniques.  In theory, these  may  include  the
following:

       Radon reduction in homes
       Electrostatic precipitators
       Areal soil gas venting and areal removal

Radon and its decay  progeny  do  not  pose  a
significant  health  hazard  in  an  open  outdoor
environment. However,  they  can  accumulate to
harmful  concentrations in confined  spaces, such as
residences  where there is an  underlying radionuclide
source.

Direct radon reduction in homes can be accomplished
in a variety of ways. Techniques include sealing entry
cracks and holes,  forced  ventilation  of soil  and
building  materials in and adjacent to the  foundation,
and passive and forced ventilation of indoor airspace.
The techniques, properly applied, are effective. These
control systems must be maintained  as long  as the
radionuclide source  is present.  The particular
techniques  to  be  applied  to a  specific  situation
depend  upon  the structural characteristics  of the
building and the nature of the underlying  soil.

Electrostatic precipitators may reduce the number of
the particles in a room including  particles to which
radon progeny are attached. The health effects of this
are not known.

Areal  soil gas venting  may be applicable to reduction
of radon emanation over a waste site. The technology
has been used  to remove methane from landfills and
organic  vapors from  soil. The effectiveness will
depend  in  part on the  soil  characteristics. Areal
removal   systems  would  require  long-term
maintenance.


Chemical Extraction of Radionuclides
from Contaminated Soil
The  objective  of this  separation  technology is to
concentrate the radioactive contaminants by chemical
extraction,  with  the aim of  thereby reducing the
volume of waste for disposal. The chemical extraction
technology  ultimately  generates two fractions.  One
fraction  contains  the  concentrated   radioactive
contaminants and may require disposal; the remaining
material is  analyzed for  residual contamination and
evaluated for replacement at the point of origin or at
suitable alternative  sites.  The various applicable
chemical extraction  techniques include extraction
with:

       water
       inorganic salts
       mineral acids
       complexing reagents

Except for the use  of inorganic chlorides to remove
radium from  liquid effluents at uranium mines, none of
the chemical extraction  technologies has been field
demonstrated to  remove radionuclides  from waste
material  at  a  site. Bench-scale  and  pilot-scale
testing  would  be  needed to  determine  whether
chemical extraction can be used for site remediation.

Water  can  be  used to extract a  portion  of  the
radionuclide  contaminants.  Contaminated  soil  or
tailings could be mixed with large quantities  of water.
The  water,  with  the soluble radionuclide  fraction,
could be removed from solids by physical separation.
Since  many of the  soil-cleaning  techniques  use
water as part of their process, this method  could be
used as pretreatment.

A  review of  the literature indicates a broad range of
results with the use of salt solutions to remove radium
and  thorium  from mill tailings  and  soils.  In  many
cases the  effectiveness of a given salt appears to be
related to several obvious variables,  such  as  the
nature of  the tailings  (geochemistry,  particle  size
distribution, and chemical composition); the  nature of
the soil; the concentration of the  salt solution;  pH;
solid-to-liquid ratio;  process  time;  temperature;  and
method of extraction.

Mineral  acid extraction techniques  are being
developed and  have  been  used  to  extract radium,
thorium,  and  uranium  from  mineral  ores.
Improvements in  these acid extraction processes
have been found to be possible in the laboratory  and
at uranium  mills. The results  show  that  the  acid
extraction processes can remove most of the metals,
both radioactive and nonradioactive,  and  therefore
may  deserve  further study  for  cleanup  of
radiologically contaminated  sites  and  tailings.
However,  different  processes  may be needed for
different radionuclides.

Extraction  with  complexing  agents differs from acid
extraction in  that  complexing  agents  like EDTA
(ethylenediaminetetraacetic acid) are used instead of
mineral acids. Radium forms  stable complexes with
many organic ligands (a molecule that can  bind to a
metal ion  to form a complex)  while thorium is not
likely  to  be  removed  by  complexation.  Laboratory
experiments  show  that  radium  forms  stable
complexes with  EDTA,  suggesting  the  potential for
                                                 xv

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extraction in soils and tailings with low concentrations
of thorium.

The above extraction processes produce  a  pregnant
liquor containing  the radionuclides.  In  treating this
liquor to  concentrate and collect the radionuclides for
disposal, the following support techniques are utilized:

       precipitation and coprecipitation
       solvent extraction
       ion exchange

By  addition of chemicals, the  radionuclides can be
precipitated out from leach liquor. The slurry from the
precipitation tank is  dewatered in thickeners;  this is
followed  by filtration. The filter cake containing  the
radionuclide  fraction is then  ready  for disposal.
Precipitation  is a  difficult,  cumbersome  operation
requiring complex chemical separation. Close control
of operating conditions is required.

Solvent extraction can  be an efficient  method  for
separating the radionuclides. In  solvent extraction, the
dissolved radionuclide fraction  is transferred from the
feed solution into the  organic  solvent phase.  The
loaded organic solvent is stripped of the  radionuclides
by an aqueous reagent.  The barren organic solvent is
recycled  back to the  extraction step. The radionuclide
is precipitated out from the aqueous liquor. Solvent
extraction offers  better selectivity and  more versatility
than ion exchange.

Ion  exchange involves the exchange of ions between
the  solution and  a solid  resin. Ion exchange  does not
extract material  from the  soil directly.  Rather, it
separates the constituents  in  a solution,  such as
might result  from  chemical extraction.  It has  been
used  extensively in  uranium and radium  extraction
from ore. There are three  types of  exchange: fixed
bed, moving bed, and  resin-in-pulp. Any of these
are  theoretically  applicable to radionuclides in liquids
as a technique to complete the chemical extraction
technology.

Because of the need for a combination of extraction
methods to remove uranium, thorium, and radium, the
chemical extraction  technologies appear to  be quite
expensive and complex.


Physical Separation of Radioactive Soil
Fractions
The radioactive contaminants in soils and tailings in
many cases  are associated with the finer fractions.
This is true for  uranium mill  tailings  and radium
processing residue.  Thus,  size separation may be
used to produce a  reduced volume  of  concentrated
material  for  disposal, leaving  "cleaner"  fractions.
These fractions  must be disposed as well. Physical
separation  may be  used with  chemical  extraction to
produce  fractions of smaller volume  with  even more
concentrated  contaminant.  The  physical  separation
technologies  may  be  suitable  for  removing
radionuclides that originally have  been  deposited  as
solid particulates on the soil.

Four  physical  separation  technologies  may   be
applicable  to  the separation  of  radioactive  waste
components of soils and tailings:

        Screening - both dry and  wet
        Classification
        Flotation
        Gravity Concentration

These processes are already extensively used in  the
extraction of uranium from ore. They have not been
used  in the field to further  extract other  radionuclides
from  tailings or  soils.  Pilot  plant testing  would   be
needed to determine the ability of  physical separation
technology to clean radiologically contaminated soils.

Screening separates soil (or soil-like  material)  on  the
basis of size. It is normally applied only to particles
greater than 250 microns in size. The process can  be
done  dry or by washing water through the  screen.
Screening is not efficient with damp  materials, which
quickly blind the screen.

Screening  can be applied  to  a variety  of materials,
and it is relatively simple and  inexpensive. It may  be
particularly effective as a first operation to remove  the
largest  particles,  followed   by  other  methods.
Screening  is a noisy  operation,  and dry  screening
requires dust  control.   Finer  screens  clog  easily.
Information needs  include  size distribution  and
moisture content of the feed stream, and  throughput
required for the equipment.

Classification  separates  particles  according to their
settling  rate in  a fluid. Several  hydraulic, mechanical,
and  nonmechanical  configurations  are  available.
Generally,  heavier and  coarser  particles  go  to  the
bottom,  and lighter,  smaller  particles  (sometimes
called  slimes)  are  removed from  the top.
Theoretically,  classifiers could  be used to  separate
the smaller particle  fractions,  which   may contain
much of the radioactive contamination in waste sites.
Classifiers could be used with chemical extraction in a
volume reduction process. Classification  is  a relatively
low-cost,  reliable operation.  Soils high  in clay and
sands high in humus, however,  are difficult to process
this   way.  Information  required  for  selecting
classification  includes   size  distribution,  specific
gravity,  and other physical characteristics of the soil.

Flotation is a  liquid-froth  separation  process  often
applied  to separate specific   minerals  (particularly
sulfides) from ores.  The process depends more  on
physical and chemical attraction phenomena between
the ore and the frothing  agents, and  on  particle size,
                                                  XVI

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than on material density.  If particles can be collected
by the froth, flotation is very effective.

Ordinarily, flotation is applied  to  fine materials; the
process often is preceded  by grinding to  reduce
particle  size.  Process effectiveness has been
demonstrated in extracting radium from uranium mill
tailings  (Raicevic, CIM  Bulletin, August  1970).
Detailed waste  characterization is a prerequisite  for
application  of  the flotation  process;  mineralogy,
chemistry,  specific gravity,  and particle size are all
important.

Gravity separation  is  used in the uranium and radium
ore  processing  industries.  This process  takes
advantage  of the difference in material densities to
separate the materials into  layers of dense and light
minerals.  Separation  is  influenced  by particle size,
density, shape,  and weight. Shaking (e.g., a shaking
table) and a variety of other motions are employed to
keep the  particles apart and  in  motion; this is  an
integral part of the  process. Gravity separation can be
used in  conjunction   with chemical extraction. One
drawback to gravity  separation is  its  generally low
throughput.  Information  needs are  essentially the
same as for flotation.

Additional  technologies  are  required to  support
separation  methods, including  sedimentation  and
filtration, both of which  are  methods  used in waste
water treatment. They may be used individually or
together.


Combined Physical Separation  and
Chemical Extraction Technologies
The combined  physical and chemical separation
techniques  that can  be applied  to decontaminate
radioactive soils are:

       Soil washing and physical separation
       Separation  and chemical extraction
       Separation, washing and extraction technique

The soil  washing  and  physical  separation  process
involves  washing  the soil  with  chemical  solution,
followed  by separation of coarse and  fine  particles.
The type of solution used for washing will depend on
the contaminant's chemical and physical composition.
In 1972 DOE initiated laboratory-scale studies of soil
cleaning techniques;  on  the basis of these studies, a
washing  and  physical  separation  process was
selected for pilot-plant study of cleaning plutonium-
contaminated soil. The  results  of that  pilot-plant
testing (at Rocky  Flats)  show this process  to have
potential for success.

In pilot-plant test  runs,  soils  contaminated  to 45,
284,  7515,  1305,  and 675 pCi/g  of plutonium were
cleaned to contamination  levels of 1, 12, 86, 340, and
89  pCi/g, respectively, using   different  washing
processes. The coarse particle weight fraction ranged
from 58 percent to 78 percent. Soil washing has been
shown to work in clay soil. This process  may  not
work  for  humus  soil.  The  process  is  simple  and
relatively inexpensive and  needs  no major process
development. It would,  however, need further pilot-
plant  testing  and  development  work  to  test  its
applicability to contaminated  soil.

In  combined  physical  separation  and  chemical
extraction,  the  soil is first  separated into  fine  and
coarse particle fractions. The coarse particle fractions
may  be washed  or extracted. The  fine particle
fractions are combined with extracted  contaminants
and could  be  sent to a  secure disposal site.  The
"clean" coarse fractions  are analyzed  for residual
contamination and  evaluated  for  placement at  the
original site or an alternate site.  An advantage of this
process  is  that  soil  containing  higher levels  of
radioactivity could  be treated. Also,  various sections
of  the process have  been  developed for extracting
uranium, and laboratory work is  underway in Canada
for extracting radium  from  uranium mill tailings.  The
main  disadvantages of this  process are that it  is
expensive and  has  high chemical usage.  In addition,
the use  of chemicals  raises  concerns of further
contamination to the environment. The process would
need  further development work in  order to  better
extract radionuclides from soil.

In  applying  the separation,  washing, and extraction
technique, the contaminated soils can conceivably be
washed with  a  variety of washing  fluids, followed by
chemical extraction. The nature  of the washing fluids
and chemicals  depends on the contaminants and on
the  characteristics  of the  soil.  It  could  be
advantageous  to separate  the  soil into fine  and
coarse fractions and use the washing system on  the
coarser soil  fraction  to reduce  the throughput  and
chemical  usage.  The  treated  soil, the  finer  soil
fractions  and  the  collected contaminants  would
require appropriate disposal.


General Issues
Several issues are of significant concern in attempting
to  apply  remedial technologies at sites  contaminated
with radioactive materials. They include:

       Final Disposal and  Disposal Siting.  Publicly
    acceptable  sites are difficult to find, and there
    may be problems in convincing the public that the
    "clean"  fractions of the treated  wastes  are truly
    acceptable. Some form of disposal may ultimately
    be necessary  as radioactivity cannot be altered or
    destroyed by any treatment technology.

       Handling  of concentrated  residuals. Reduc-
    ing  the  volume  of radiologically  contaminated
    waste will increase  the  concentration   of
                                                  XVII

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    radionuclides and may substantially increase  the
    safety hazards of the contaminated fractions.

       Mixed Wastes.  It is important to note  that in
    some  cases there  may be  two  categories  of
    residual contamination: process wastes and soils
    contaminated with  isolated  radionuclides   or
    groups of  radionuclides. While  removal  of  the
    radioactive fractions of soils contaminated with
    single radionuclides  such as uranium or plutonium
    might  result  in  "clean" fractions acceptable  for
    unrestricted disposal, removal of the radioactivity
    from  a soil  contaminated with  process wastes
    may not. In this  second case, the  nonradioactive
    fractions  of  the residues could  result  in  an
    unacceptable  product.  Therefore, before
    considering  any separation  technique,  it  is
    necessary  that  acceptable limits  for  both  the
    radiological  contaminants  and the   non-
    radiological  contaminants  be  defined.  In  some
    cases multiple  treatments  or  combined
    technologies could  be  required to  achieve
    environmental goals.
land.  Alternative  technologies,  which  have  to  be
evaluated  and discussed further,  may have the
potential for reducing the mobility, toxicity, or volume
of these contaminants.  Further  studies  need to  be
completed prior  to the  implementation of  these
alternatives.
Criteria for Further Studies
The utility of any potential treatment process and the
applicability of the overall  remedial  action depend
heavily on  the  physical  characteristics  of the
contaminated media and the surrounding soils. Since
none  of the  chemical extraction and physical
separation technologies  have been used  in  a site
remediation  situation,  their  application  must  be
approached cautiously.  The  same holds true  for
solidification  or  stabilization processes.  Only land
encapsulation and ocean disposal have been used.

It  is  important  to study  the  patterns  in  waste
characteristics  at various sites  and  develop  waste
groups with similar major characteristics. Applicability
studies  can  identify  promising  technologies  to  be
tested for treatment of each waste group. Preliminary
screening of the technologies can  be accomplished
based primarily on the waste characteristics.

When one or more remediation concepts are selected
that appear applicable to a  site,  plans may be made
for treatability studies. Success  there  could  lead to
pilot-scale  testing  and eventually  to  full-scale
demonstration  of site cleanup.  This  step-wise
procedure  is essential  for  the development  of any
remediation technology, with carefully developed work
plans  and quality assurance  plans preceding  each
step.
Conclusions
The  remediation  of  radioactively contaminated sites
under Superfund,  FUSRAP, and UMTRAP  has been
hampered  by the  lack of  methods other than
temporary storage or permanent  encapsulation  on
                                                XVIII

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                                             Chapter 1
                                           Introduction
1.1  Study Purpose and Objectives

The  Environmental Protection  Agency  (EPA) has
identified twenty Superfund sites in the country that
are  radiologically  contaminated  by man-made
sources  (see  Appendix  B).  These  sites,  located
across the United States, vary greatly in size and may
involve  radiation exposure to people who reside on
and  around  them.  Radionuclides,   unlike  other
hazardous wastes, cannot  be altered or destroyed to
eliminate their hazard potential.

The principal objective of this document is to identify
the full  range of technologies that  may be useful in
reducing to acceptable levels  the radioactivity  at
uncontrolled hazardous  waste  sites.   Many of  the
technologies  discussed  would  require  significant
research and development  activities before they could
be reasonably considered for site cleanup. This  report
only  addresses  treatment   and   disposal  of
radiologically  contaminated soils; it does not deal
with, for example, sites whose principal  radiological
contamination is in building  materials.  Radiologically
contaminated  ground water is also a concern at some
Superfund  sites,  but ground  water  treatment  is
beyond the scope of this report.

The  document  is  intended  as  a  first review. This
report provides  a discussion of the technologies, but
not a detailed critical  evaluation of them. The  report
does  not include  in-depth analyses that would be
needed to determine the applicability of any of  these
technologies at a particular site.

In  order to better ascertain the applicability  of  the
technologies, descriptive data have  been gathered for
the twenty  sites identified on the  National Priorities
List (NPL) that are known to contain radioactive  waste
materials. These data are  presented in Appendix  B;
they are accurate as of December 1987.

1.2  Health Concerns

The radioactive materials at Superfund sites consist
primarily of  wastes from radium, thorium, and uranium
processing. These wastes  contain residual quantities
of these  elements  and  their  radioactive  decay
products, which  have remained  as contaminants in
buildings,  soil material, and  stream channels  after
operations at the sites have ceased-or have  been
dumped  as  waste  in  on-site  or off-site disposal
areas.  Contaminated  soils  have  sometimes  been
utilized as fill material on private and public properties
for various  purposes.  There  are  many  other
radionuclides that  may  also  be  impacted  by
technologies in this report.

The radioisotopes of concern belong to the uranium
238 and thorium 232  decay series  (see  Figure  1).
Hazards to  the  general  population  could  occur
through several pathways, including:

   (1) inhalation  of  radon  decay  products,
       particularly  where  radon  is concentrated
       within building structures;
   (2) inhalation of  particulates or  ingestion  of
       materials containing radioisotopes of the two
       decay series;
   (3) ingestion of radionuclides via drinking water
       and food; and
   (4) external body exposure to gamma radiation.

In  the  absence  of  remedial  action,  these potential
hazards  could persist  for  extremely  long periods
(millions  of years) because  of the long half-lives of
the controlling isotopes.

There are three  types  of radiation  generally believed
to  pose health hazards.

One is the alpha radiation (positively  charged  nuclear
particles) associated with radioactive decay of radon
gas and  other radioactive elements,  such  as radium
and uranium. Although  alpha radiation  cannot  pass
through the outer layers of skin, it can enter the body
through inhalation and  ingestion. Inhalation of alpha-
emitting particles is a major health hazard and may
contribute to  lung  cancer.  Ingestion  of water,  dust,
plants,  or animals that contain  alpha-emitters may
contribute to cancer in  the various parts of the body
where  the alpha-emitters lodge.

The second type of radiation that may pose a health
hazard is gamma radiation.  Gamma  emitters can
contribute to  external  exposure, since  they can
irradiate  the  human   body.  Such  exposure can

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Figure 1.    Uranium-238 decay series.
                  Protactmium-
                   234
                  1 2 minutes
                   beta,
                   gamma
contribute to cancer  in  various parts of the body.
Different  measures may  be  required  to  reduce
exposure to alpha and gamma radiation.

The third type  of  radiation  is  beta  radiation
(electrons). Energetic beta particles can pass through
skin.  The primary hazard from  beta radiation,
however,  is  internal  deposition  by  ingestion or
inhalation. Although decay of radium to  radon does
not produce beta radiation,  a subsequent portion of
the decay chain  produces beta radiation.  The  beta
radiation is of secondary concern relative to the alpha
and  gamma  radiation, as  the associated risks  are
typically much lower.

The  principal health  concern  at  sites containing
radioactive wastes has been  radon,  radon  progeny,
and  gamma  radiation  from  radionuclide decay. The
primary gamma radiation source  at  waste  sites  is
radium in the soil. In  addition, radon gas is continually
produced by radioactive decay of radium, as indicated
in  Figure  1.  Radon  and its decay  products (radon

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"progeny")  are  alpha  emitters  that are  potentially
injurious if  they  become lodged  in the  respiratory
system, and gamma emitters. Radon in the soil can
make its  way  through  cracks and  porous building
materials  and  accumulate  in  unsafe concentrations
within houses and other buildings and enclosures [1].

Radon  has  a  half-life of 3.8  days;  its  progeny are
radioactive particles. They can attach themselves  to
dust and  other particles. If  they are inhaled, either
attached or unattached  to other particles,  they  may
deposit  in the  respiratory  system where  they  emit
alpha particles,  which  may  be  damaging to the
tissues. Alpha-emitting particles from decay of radon
and  progeny are  considered to  be a cause of  lung
cancer  [2].

Residences and other  buildings have been built on
and  around  some waste  disposal sites contaminated
with radioactive  materials.  The  radiation  hazard
derives  from elevated indoor concentrations of radon
gas and elevated outdoor and indoor gamma radiation
levels  that  approach and   sometimes  exceed the
radiological  standards for the general  public.  It  is
important  to note that there  are  average background
radiation  levels  associated with  these  materials.
Typical  levels are shown in  Table 1; they may not be
the  same  as  the average  level  in  any  particular
location.

Sites that  contain radioactive waste materials  may
also contain other types of hazardous waste. Some  of
the  Superfund  sites, for example, contain various
types  of  hazardous wastes,  and  the  radioactive
portion  may pose  a  relatively  minor  threat  by
comparison. The presence  of  other  hazardous
materials may complicate dealing with the  radioactive
portion of  the  waste  and  vice-versa.  EPA  is
developing  special  regulatory approaches  to  these
"mixed  wastes."

1.3  Waste Sources  and Contaminated
     Media
Radioactive  wastes  at uncontrolled sites  have come
from a variety of sources. Perhaps the most common,
at least at  Superfund  sites, has  been  the residual
material derived  from  ore  processing  to obtain
radioactive elements. Examples are wastes from the
beneficiation of  uranium-,  radium-, and  thorium-
bearing  ores and  from  the  process use  of  these
elements.  A common  use for  radium  has  been
luminous  watch dials;  thorium has  been  used for
mantles for gas  lanterns.

It appears that most of the  contaminated wastes are
in tailings, a soil-like matrix.  The radium and thorium
wastes exist in relatively  small quantities at most sites
in comparison to uranium mining and mill tailings and
the wastes from nuclear fuel  processing and handling.
 Table 1. Typical Background Radiation Levels*
 	Component	Typical Background
  Gamma radiation
  Ra-226 or Ra-228 in soil
  Uranium in soil
  Th-232 in soil
  Ra-226 in water with Ra-228
  U-238 in water
  Radon in air (outdoor)
  Radon in air (indoor)
8-13nR/h
 ~ 1 pCi/g
 ~1 pCi/g
 ~1 pCi/g
 ~1 pCi/l
 ~1 pCi/l
 0.2 pCi/l
 ~1 pCi/l
 These may not be the same as the average level in any particular
 location.
Fuel  processing, handling,  and use  may result  in
relatively highly  contaminated containers,  equipment,
and  even spent fuel  residuals.  Nuclear  fuel wastes
are generally maintained in containers at the use site
(e.g., nuclear power and generating plants) until their
final disposition.  Superfund sites for the most part do
not appear to contain these types of materials.

1.4  Scope of Report

Chapters 2 through 7  describe the  range  of
technologies for the removal of  radioactive materials
from contaminated  soil.  These sections  deal,
respectively, with disposal of contaminated materials,
on-site treatment, radon control  chemical extraction,
physical  separation, and  process  combinations to
remove contaminants  from soil. The descriptions are
the result of literature surveys  and discussions with
experts who have  dealt  with  similar problems.  It
should be noted  that the radioactive contaminants are
not altered  or destroyed  by treatment technologies.
The  volume  of contaminated material may be reduced
by  treatment,  but  the  concentration  of  the
contaminants will be  much  higher in the  reduced
volume. Some  type of containment and/or  burial  is
the only ultimate remedy  for materials contaminated
at levels above those considered safe for  unrestricted
release.

Chapter 8 briefly points out some  of the issues  that
may inhibit or otherwise affect the remediation of sites
containing radioactive  waste. The issues  include,  for
example, siting for final disposal, public reaction,  and
costs.

Chapter  9  looks  at  potential  experimental work
(bench-scale  studies, for  example) to  test  the
applicability  of   the  alternative   remediation
technologies.

Chapter 10 presents the conclusions of this report.

Appendix  A  briefly  presents  some  of the
laws,regulations,  and  guidance  that are  part of  the
framework within which technologies may  be selected
for remediation  of Superfund sites.  This report does

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not attempt nor is it intended to provide a complete or
detailed analysis of how various laws, regulations, and
guidance apply in  general or at a specific Superfund
site, nor is it intended to set or interpret policy for the
selection or use  of  technologies  to clean  up  any
Superfund or other hazardous waste site.

Existing Superfund sites known to contain radioactive
materials are briefly  characterized in  Appendix B.
Descriptive  data  include:  the location,  size  and
volume of the  site;  the  character  of the  matrix
materials; proximity to population centers; the degree
of contamination;  and  the  status  of  survey  and
cleanup activities. Data also  have  been  gathered on
sites   being  managed and  remediated  by   the
Department of Energy (DOE)  [3]. This information is
also presented in Appendix B.

Descriptive  data  on  Superfund   sites  where
radioactivity is a concern were obtained from the  EPA
Office  of Solid Waste and Emergency  Response  and
from each of  the pertinent EPA Regional  Offices,
Information on DOE sites was obtained from literature
provided  by the Oak Ridge National Laboratory
(ORNL) and the EPA Research Library in Cincinnati,
from DOE personnel, and  from  the  staff of EPA's
Office  of Radiation Programs.

Site-specific information is not complete at this time.
For example, only limited  information has been found
on the soil or matrix characteristics at some of the
Superfund sites. Detailed  information on the physical,
chemical, and radiological characteristics is absolutely
necessary  before attempting  to apply  any of  the
alternative technologies.

1.5  References

1.  Nero, A. V. Airborne Radionuclides and Radiation
    in  Buildings:  A review.  LBL-12948.  Lawrence
    Berkeley Laboratory, University  of California.
    1981.

2.  U.S. Environmental Protection Agency.  Radon
    Reduction Techniques  for Detached  Houses:
    Technical  Guidance  (Second  Edition).  EPA-
    625/5-87-019    Office of  Research  and
    Development, Washington D.C. 1987.

3.  U.S. Department of Energy. Office  of Remedial
    Action and Waste Technology Program Summary,
    DOE/NE-0075, November 1986.

-------
                                              Chapter 2
                                               Disposal
2.1  Introduction
This chapter  discusses  remediation  methods that
show potential for use in the  final disposal of  radio-
active  waste  materials.  Final  disposal is  generally
regarded as some sort of containment that separates
the materials from any further  contact with  the  public
and the environment.  The radioactive  waste materials
may be in  the form of tailings or tailings mixed with
soil.

If some of the technologies described in this  report
are applied prior to  containment, the contaminated
waste  volume may be  reduced with a concomitant
increase in  the concentration of  the  radioactive
material. Additionally, the  larger  fractions of  the
treated  soil may be suitable for replacement at  the
point of origin without any long-term management,  if
the treatment technology succeeds  in reducing  the
residual radiation to an acceptable level.  No matter
what technologies are applied, there will  always be
some portion  of  the  material  that will require long-
term disposal.

On the other hand, the  radioactive  waste  materials
may  not  be in  a  form  amenable to   volume
reduction-e.g., contaminated equipment; these also
must  be permanently contained  if they  cannot be
cleaned.

Disposal can  be in  one  of two  categories: on-site
disposal and off-site disposal.  The state of the  art of
on-site  and off-site disposal  methods is  shown  in
Table 2. Applicability  of these  methods to Superfund
sites is controlled by  site-specific  factors;  therefore,
their usefulness   must be  determined on a site-by-
site basis. At present,  capping  and  land encapsulation
are the  only  two methods used  for radiologically
contaminated site remediation.

2.2  On-Site Disposal

It  may  be  possible to  deal  with  radioactive waste
materials, particularly  if they are in a soil matrix, by
methods that  do not  remove  either the soil  or  the
radionuclides from the site. Methods include: capping
and vertical barriers.
2.2.7    Capping

2.2.1.1   Description and Development Status

This concept involves covering the contaminated  site
with a barrier sufficiently thick  and impermeable to
minimize the diffusion of radon gas. Barrier materials
can be  either natural  low-permeability soils  (e.g.,
clay) or  synthetic  membrane  liners, or  both. Both
types of materials  are  generally available.  A barrier
might  consist of  several feet  of  compacted clay,
depending  upon radiation levels, and extending a  few
feet beyond the perimeter of the contaminated area.

Cap design  and construction  should  consider  the
need to:  1) confine  radon  until  it has  essentially
decayed  to its progeny (for normal soils, the depth of
cover required is  about 150  cm  for Rn-222 and  5
cm  for  Rn-220); 2) attenuate the gamma radiation
associated   with all  the radionuclides  present  (for
normal soils, the depth  of cover required  for gamma
radiation  shielding  is on  the order of 60 cm);  3)
provide long-term  minimization  of water  infiltration
into the contaminated  material;  4)  function  with
minimum  maintenance;  5)  promote drainage and
minimize erosion;  and  6)  have a permeability less
than or equal to the permeability of any bottom liner
system present or the natural subsoils.

Radon is  continually  produced  from the radium
source, but the radon itself  decays in a few days. A
schematic  diagram of  one  potential cap  design is
shown in  Figure 2 [1]. A  number of DOE  facilities
have been  constructed using the  criteria  contained
therein.  The technology of  caps  is well  developed,
and several  good  references are  available  [2-7].
However horizontal  migration  of  radium  or  other
radionuclides in ground water could still occur.


2.2.1.2   Potential Applicable Situations

Capping  a  waste mass in  situ  is applicable over  a
large, discrete, contaminated area  or as a  continuous
cover over  several  smaller areas that  are  close
together.  Since there  is  a  greater  likelihood  of
penetration through the cover if structures are built
upon it, capping  is best used when no structures  are
planned for  the site. All reasonable steps  should be

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Table 2. State of the Art of Disposal Methods


Laboratory
Method Testing

Bench
Scale
Testing

Pilot
Plant
Testing
Field
Demonstration
with
Radioactive
Material

Radiologically
Contaminated
Site
Remediation


Remarks
On-site Disposal
    Capping
    Vertical barriers
Off-site Disposal
    Land encapsulation
    Land spreading

    Underground mine disposal

    Ocean disposal
                   Land spreading of radium sludge from
                   drinking water is an allowed policy in Illinois
                   DOE currently  working on mined repository
                   for radioactive  waste
                   Stringent regulations for radioactive waste
taken  to  prevent or prohibit construction  of buildings
on capped wastes as long as possible.


2.2.1.3   Advantages and Disadvantages
Advantages  - The advantages of capping are ease
of  application,  the  fact  that  it  is  a   well-known
technology,  and  its high reliability  when  maintained
properly.  Another advantage of in  situ capping is its
relatively  low cost. Covers that are effective Rn-222
barriers  may be effective  gamma  radiation  shields.
The soil characteristics are  not as critical as they may
be for stabilization or other treatment technologies.

Disadvantages   - Capping  the  radon-emitting site
does nothing to  eliminate the  source of  radioactivity
from the  area of concern.  It simply impedes release
by shielding and trapping. Thus, the cap must remain
Figure  2.    Schematic of a cover profile. (Reprinted from [1].)
           Swale
    Select  3  ;
   i Soil     c
                           Cover
                           3'-0" Thick
       Rip-Rap
       T-6" Thick
                                Encapsulated Radioactively
                                  Contaminated Material
                                           Original /
                                           Ground
                                           Surface
        Select Soil
        1'-0" Thick
             Rip-Rap
       5   /- 1'-6" Thick
        i
                                  n
                                                                                                  Rip-Rap
                                                                                                    2'-6" Thick

-------
 intact,  without  penetrations,  indefinitely.  Tree roots,
 excavations  for various  purposes,  such as  utilities
 repair,  and  unwitting  excavations  or  penetrations
 (e.g.,  post holes) could  result in significant leaks.
 Building construction, as indicated above, is  a clear
 threat to a cap. In addition migration of  uranium and
 radium in the ground water could still occur.


 2.2.1.4   Information Needs
 As  noted above, capping  probably can be  applied
 without  the  detailed  site materials  characterization
 necessary for  most other  types  of remediation.
 However, it  must  be  determined  whether other
 hazardous  materials are   present;  remediation
 requirements  for  nonradioactive hazardous  materials
 may take precedence.


 2.2.2     Vertical Barriers

 2.2.2.1    Description and Development Status
 Vertical  barrier walls may  be installed  around the
 contaminated zone to help confine the material  and
 any contaminated ground water that might otherwise
 flow from the site. The barrier  walls, which  might be
 in the form  of  slurry walls  or grout  curtains [8,9],
 would have to reach  down to an impermeable  natural
 horizontal barrier,  such as a clay zone, in  order to be
 effective  in  impeding ground-water  flow.  A  barrier
 wall in combination with a surface  cap could produce
 an  essentially  complete containment  structure
 surrounding the waste mass.

 Slurry walls are constructed  by excavating  a  trench
 under a  slurry. The  slurry could  be  bentonite  and
 water or it could  be  Portland cement, bentonite  and
 water. In  cases  where  strength  is  required of  a
 vertical  barrier,  diaphragm walls are constructed with
 pre-cast or cast-in-place concrete panels  [9].

 An illustration of the  slurry wall construction process
 is shown in Figure 3.

 Grout  curtains  [9]  are  constructed  by pressure-
 injecting grout directly into the soil at closely spaced
 intervals around the waste site (Figure 4).

 The spacing is selected so that each "pillar" of grout
 intersects the next, thus forming a  continuous  wall or
 curtain.  Various  kinds of grout can be used, such as
 Portland  cement,  alkali silicate grouts, and organic
 polymers.


2.2.2.2   Potential Applicable Situations
Vertical  barriers could be considered  for use  to
prevent or delay escape of liquids and perhaps gases
(if installed in combination with a cap), until a more
  Figure 3.    Slurry trench construction operations. (Reprinted
             from [9].)
  Figure 4.    Grout curtain around waste site. (Reprinted from
             [9].)
     Semicircular
     Grout Curtain
                     Secondary
                    Grout Tubes
                          Primary
                        Grout Tubes
desirable  permanent  remediation  technology  is
adopted.

Barrier  walls  could be considered  only  for  large
discrete masses of waste materials or around several
smaller masses close  together. Barrier walls  are  not
totally impermeable to water.


2.2.2.3   Advantages and Disadvantages

Advantages -  Vertical  barriers in soil  and  soil-like
materials  are  relatively simple to  install.  They may
save the  expense  of  excavating  and  removing  the
contaminated material.  In addition, they might serve
as a vessel within which an  in situ treatment process,
such as contaminant extraction, could be carried out.

Disadvantages  -  It is  difficult to obtain  truly  low
permeabilities  in  grout  curtains  constructed   in

-------
unconsolidated materials  [6]. Neither  slurry  wall nor
grout curtain does anything,  in itself, to eliminate the
problem  of  radioactivity  or  any other contaminant.
Each simply  improves  the  confinement  of  the
contaminants to the site.

Another  potential  disadvantage  is  the  possible
deterioration of the barrier  walls resulting  from the
chemicals contained in the waste, particularly organic
chemicals. A vertical  barrier would  not  stop vertical
contamination to ground water below.

As  with  caps,  barrier walls do not eliminate the
radioactive contents of the enclosed waste.  They can
only inhibit the spread of the contaminants.  They do
not inhibit the release of radon as a cap would.


2.2.2.4   Information  Needs
The successful installation of a vertical barrier wall by
the  slurry  wall or  grout curtain technique requires
detailed  prior  knowledge of the soil's physical and
chemical  characteristics [9].  As a  minimum, the
characterization   of  any   liquid  contaminants  is
required.  Many   common  chemical  (particularly
organic)  contaminants at  uncontrolled waste sites can
destroy certain grout materials or prevent them from
setting.

2.3  Off-Site Disposal

Off-site disposal,  as the term  is used  here,  means
controlled  disposal at a site  that  is engineered  or
chosen   for  the  purpose  because  of  certain
characteristics. Hydrogeological  conditions at the site
is  one  of the factors that must be  considered  in
selecting off-site  land disposal  sites.  Disposal  may
be very  near the  contaminated  site  or it may be very
remote. The choice may  depend upon site availability,
security,  public acceptance, cost,  safety,  and other
factors.  Off-site disposal is  considered here to be  a
final  stage  of remediation,  whether it is applied  to
untreated waste or to the extracted, encapsulated,  or
solidified wastes.  Land encapsulation, land spreading,
underground mine disposal, and ocean  disposal  are
the  off-site disposal methods reviewed  in this
chapter.

 In  the case of radioactive  waste it is not clear that
 disposal with  treatment  will be superior to  disposal
 without  treatment.  The off-site  disposal  technologies
 are discussed here without attempting to judge their
 relative acceptability. Given  the length of  time that the
 radioactive waste will  be a hazard, the  design must
 include  greater  attention  to  degradational
 characteristics of  construction materials  than has
 been normally  considered for  hazardous waste
 disposal sites.
2.3.7     Land Encapsulation

2.3.1.1   Description and Development Status
Land  encapsulation  is a  proven, well-demonstrated
technology.  EPA has produced  many  publications
dealing  with the technology of hazardous waste land
encapsulation   (all  of the Technical  Resource
Document  series) [10]. Figure 5 is a  cross-section
of a  conceptual design   of a   land  encapsulation
structure  [1,11]. Nuclear  Regulatory  Commission
(NRC) and EPA  have jointly developed guidance  on
land encapsulation siting and design for  commercial
mixed low-level  radioactive and hazardous waste
disposal facilities [6,7] (see Appendix A, Addenda).

Land  encapsulation is a technology that is likely to be
considered at some stage in every site  remediation
case, especially with radioactive  wastes, because the
radioactivity  cannot be  altered  or  destroyed.
Alternative technologies may be applied to the waste,
as  described later,  to reduce  its volume,  but  the
concentrated contaminants must still  be contained.
DOE  has used land  encapsulation or some variant of
it at  the FUSRAP sites  that have been remediated
(see Appendix B).

Land  encapsulation  can occur on site, but  this may
not be  an option in  all  situations. If  a radioactive
material processing  plant  is the  source of the waste
and is  near  the contaminated  area,  the plant  site
could be a prime possibility for the land encapsulation
location.

Alternatively,  a  remote site dedicated by a  state or
other  government   entity  to   radioactive  waste
containment, possibly could receive waste  from  any
number of  sources  within  the  state.  The  control
inefficiencies associated with operating diverse sites
over  long periods could thus be minimized.

A variation of  the  in-state  concept  might  be  the
placement of the radioactive waste  in the base of a
new  municipal  solid waste  landfill. The landfill would
require a low-permeability  liner.  The solid waste atop
the  radioactive waste would delay the emission of
radon until it had decayed and would absorb  gamma
radiation. Since the eventual land encapsulation cover
would not be breached,  at least for many years,  the
radioactivity  would  not  be  of  significant  concern.
There  is potential  for problems  if  landfill  leachates
were to mobilize the  radionuclides  buried below  the
garbage. Another possible problem  with this concept
 is methane generation in the municipal waste. If  the
 methane should escape, radon might escape with it.

 There  are three existing NRC-licensed (by states)
 commercial  low-level radioactive  waste  sites,  at
 Hanford, WA;   Beatty, NV;  and  Barnwell,  SO.  The
 Barnwell site cannot  accept radium waste. Although
 probably capable of safely  containing the waste from

-------
 Figure 5.    Schematic of a land encapsulation system. (Reprinted from [1].)
                          Cover
                           3'-0" Thick
           Swale
       Rip-Rap
       2'-6" Thick
                                                              r
                                                                Select Soil
                                                                1'-0" Thick
                              - -  Encapsulated Radioactively'
                                    rnntammated Material
                                                                    Rip-Rap
                                                               5   /1'-6" Thick
                     Liner
                     2'-0" Thick
Capillary
Break
1'-0" Thick
                                              -- Original Ground
                                                   Surface
                                                                Select
                                                                 Fill
                                                               Material
                                         Filter Bed --jrT
                                         0'-9" Thick  KV1 1
                                                      'SRip-Rap
                                                       ^  1'-6" Thick
                                                       vri
                                                       \'  Detention
                                                       ':"  Basin
Superfund sites,  the other two may be  reluctant to
accept the wastes for many reasons, not the least of
which is the scarcity of containment space.  States in
which  these facilities are  found  are  beginning  to
refuse wastes from outside their state or outside their
compact  states,  and  are  permitted to do so  under
LLRWPA. Disposal  at  such remote  out-of-state
sites  may well be the most  difficult, and the most
expensive, of the land encapsulation options  [1].


2.3.1.2   Potential Applicable Situations
Land  encapsulation  may be  appropriate  for wastes
that  have  not  been  treated,  as  well  as  for
radionuclides extracted from  a soil or  other type of
matrix.  In fact, it  may be  the most appropriate final
disposal method in most  situations. To date,  DOE has
been  utilizing either  temporary storage  or permanent
encapsulation   as   the  most  viable  remedial
alternatives.
2.3.1.3   Advantages and Disadvantages
Advantages  -  Land  encapsulation  is a  proven,
workable  technology for the disposal  of low-level
radioactive wastes.  It can be a  viable  solution  at a
reasonable cost. The radionuclides would be removed
from the site and would not  be  a significant problem
at that site.

Disadvantages  - Finding an appropriate  site  for
construction of a land encapsulation  may  be difficult
due to the current public aversion to  this technology.
Finding   an   existing   secure  site  outside  the
containment  property that  will  accept radioactive
                   wastes  may  also  be   difficult.   Outside  the
                   contaminated  property  the  wastes will  require
                   transportation  and handling.  Transportation of  large
                   volumes of radioactive materials  also  carries  certain
                   costs and risks. There will be considerations of safety
                   and permitting in any case,  but  if the radionuclides
                   have been concentrated by extraction  and  separation
                   processes,  these  problems  may become  more
                   difficult. Longevity is a consideration in the design of
                   the disposal site.  An appropriate  site will have to be
                   found for the radionuclide concentrated fraction of the
                   material. In  any case, the disposal site  issue will have
                   to be faced at some future date.


                   2.3.1.4  Information Needs

                   Relative to other technologies,  minimal information
                   about the site  soil characteristics is required prior to
                   land encapsulation.  The levels of radioactivity  and
                   quantities of nonradioactive hazardous materials are
                   certainly important,  but  soil grain size  and  other
                   physical characteristics  do  not  have a  significant
                   impact  on  applicability of  encapsulation.   Other
                   characteristics of the potential disposal  site, however,
                   must be fully analyzed.


                   2.3.2    Land Spreading

                   2.3.2.1   Description and Development Status
                   A disposal option not often  considered  for radioactive
                   waste  is spreading  on land  [12]. This could  be  an
                   option  for untreated soil with low radioactivity  levels.
                   The material could be transported to an appropriately
                   selected and sufficiently large expanse of  remote

-------
open  land  and  spread to a  degree  that  the  soil
radioactivity  level approaches the natural background
radiation  level of these materials. The  material  can
also be blended with clean fill for dilution and then
spread over the land or disposed under road beds.
This technology has  not been demonstrated  for
radioactive  waste. Land spreading of radium sludge
from drinking water treatment systems  has  been an
allowed policy in Illinois since 1984.


2.3.2.2   Potential Applicable Situations
Land  spreading  appears to be more appropriate for
dry, granular, soil-like  materials  or  tailings  that  are
not mixed with other contaminants.


2.3.2.3   Advantages and Disadvantages
Advantages -  The technology  appears simple  and
relatively inexpensive;  it could result in a permanent
remedy for the contaminated sites involved.

Disadvantages   -  Selecting  a  site  to  receive  the
materials would  likely  be a  politically  and  socially
sensitive issue.  The types of  materials  that  could be
accepted  would  probably  fall within a  very narrow
range  of physical and chemical  characteristics.  The
technology  has  not been  demonstrated.  Convincing
the  public   of its  safety  would  be  very difficult. A
potential problem may  be emitting respirable particles
into the  air. Land spreading could contribute  to a
non-point source pollution  problem  generated by
native soil.

2.3.2.4  Information Needs
Because this  technology  is  an untried  concept,
information  needs have not  been  worked  out.
However, there seems to be no doubt that detailed
physical  and chemical characteristics  of the waste
matrix would need  to be  gathered.  Site  selection
criteria would have to  be  developed for the  receiving
site.

2.3.3    Underground Mine  Disposal

2.3.3.1  Description and Development Status
Abandoned mines could  provide  sites  for  the
 permanent  disposal of  radiologically  contaminated
 wastes. A conceptual layout of a mine disposal facility
 is  shown in Figure 6. This is  one way to plan for
 distance between  the radioactively  contaminated
 material and the human  population, although ground
 water could provide  a  route for the  contaminated
 material to  reach  the population. Some research has
 been  done on  the possibility of using  mines for the
 disposal  of hazardous  waste  [12-14]  and,  more
 specifically, for  dioxin-contammated  wastes in
 Missouri [15].  In the latter case, abandoned mines in
 that  state  were examined.   The  results   were
encouraging from  a technical  standpoint,  but the
concept has never  been implemented  in the United
States.

The DOE is currently working on a mine repository for
radioactive  waste  called the Waste  Isolation  Pilot
Project (WIPP)  in New Mexico. While this repository
is designed for  higher activity materials than most of
the Superfund  material,  the  concept  might  be
applicable,  particularly  in  light  of  the  possibility  of
volume  reduction.   Mine  containment of hazardous
waste in  Europe  has  been  successful   [16].
Multipurpose use of a mine for hazardous waste and
for  low-level radioactive waste  might be considered
and would  likely reduce the per-unit costs of waste
disposal.

Underground mine disposal would not be appropriate
for radiologically  contaminated  bulk  liquids  or
noncontamenzed waste.

For  mine  disposal, as  for  any  off-site  disposal,
excavation  of  the  contaminated materials  would  be
necessary, and they would have to  be  transported to
an appropriate site.

Any of the waste volume  reduction and  solidification
or vitrification techniques described in this  document
might be used prior to  mine disposal. Solidification or
vitrification of the material, whether or not the volume
has been reduced,  could provide even more security
for final containment in  the mine.

The principal drawback to the mine disposal option
may be cost. The use  of an existing abandoned mine
might overcome that obstacle.  With appropriate  site
selection,  there are few,  if any,  technical  disad-
vantages to this option.

2.3.3.2   Potential  Applicable Situations
Mine  disposal  might be  considered for use  for a
variety  of  radionuclide and matrix types.  As  noted
above, it could be  used to dispose of wastes with or
without prior treatment,  although  volume  reduction
and/or solidification or  vitrification  might  facilitate the
process.  Wastes  that have  been  concentrated  by
extraction or  separation  techniques   may  be
particularly appropriate for mine disposal, since they
are likely  to  be more  radioactive,  requiring disposal
that is more remote and more secure.


2.3.3.3  Advantages  and Disadvantages
Advantages   -    Mine  disposal,  if done  properly,
 should provide a very secure and remote containment
of radioactive wastes. This technology has  been used
 successfully in Europe for hazardous waste.

 Disadvantages  -   The mine disposal of  hazardous
 radioactive waste  may be among  the  more  costly
                                                   10

-------
Figure 6.    Conceptual view of a mine storage facility. (Reprinted from [1 3].)
     Maintenance
        Shops
                                      Reprocessing
                                          Plant
                                                                                    Administrative
                                                                                       Offices
                                                                                           Security
                                                                                            Office
                                             Hazardous Waste
                                              Storage Cells
                 Area Shown
disposal  alternatives,  particularly  if  a mine  must be
excavated  for only that purpose. Wastes  must be
excavated and transported with the associated permit
and safety  concerns. The use of an abandoned mine
would  involve the cost  of  reconstruction  and  may
pose safety hazards. Also, the ground water must be
protected.


2.3.3.4   Information  Needs
As with most technologies, the waste being dealt with
must be  carefully characterized. The mine site must
also be carefully described and judgments made as to
feasibility  or applicability   on  the  basis  of the
information gathered.  For example, the hydrogeology
must be  known  in detail, so that any ground  water
contamination may be prevented.


2.3.4     Ocean Disposal

2.3.4.1   Description  and Development Status

The  concept  of ocean   disposal  of  low-level
radioactive  wastes is not  new. As shown in Table 3, a
sizable amount of these wastes was  disposed at sea
between  1946 and 1970 [17].

The radioactive wastes that  have been disposed at
sea  were   usually  in  concrete-filled  drums or
containers. Three sites  were used in the  Atlantic
Ocean.  One was 12-15 miles from the coast in 300
feet of water near Massachusetts Bay.  The other two
were in water  deeper than 6,000 feet,  one 150 miles
off Sandy Hook,  NJ, and the other 105  miles off Cape
Henry, VA.

Two sites were  used in the Pacific about  48 miles
west of San Francisco [17].


2.3.4.2   Potential Applicable Situations
Ocean disposal  could be considered for tailings and
other radiologically contaminated soils that are free of
other  hazardous  wastes. This alternative  should  not
be considered for enhanced  radioactive materials  or
concentrated residuals. Stabilization techniques could
be  applied to the  waste  before  emplacement  to
provide for more security  against  leaks. For  those
materials contaminated with hazardous  chemicals,  the
potential danger  to marine biota must be evaluated.


2.3.4.3   Advantages and Disadvantages

Advantages -  Ocean disposal offers the  opportunity
for extreme isolation  of low-level  radioactive waste.

Disadvantages - Transportation  of  the contaminated
materials will involve transfer between land and sea. If
                                                  11

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   Table 3. Ocean-Disposed Low-Level Radioactive
          Waste, 1946-1970
Year
1946-1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
Number of
Containers
76,201
4,067
6,120
129
114
24
43
12
0
26
3
Estimated activity at time of
disposal (in curies)
93,600
275
478
9
20
5
105
62
0
26
3
      Totals	86,758	94,673	


the radioactive contaminants should be released,  the
potential for dispersal and dilution is immense.


2.3.4.4   Information Needs
Detailed characterization of the matrix, including other
hazardous materials,  would  be required before ocean
disposal could  be  considered.  If  solidification  or
vitrification,  as used  in  past  disposal  of  radioactive
materials,  were  first applied  to the waste,  the
chemical compatibility of the solidification agents and
the waste  would need to be  determined.  However,
solidification or vitrification is  not  required;  alt  that is
needed is an  assurance  that the material  will  reach
the bottom and will not stay  suspended in the water.

2.4 Typical Costs of Disposal Methods

The cost of the application of any  of the disposal
methods described in this chapter will depend upon
many factors,  including waste  and site characteristics.
Thus  the  costs cannot be estimated reliably  for any
method and for any  site at  this stage, because most
of the prerequisite information is not available. It also
must  be cautioned  that  many,  if not most,  of  the
controlling factors will be  site-specific. The  cost for a
method at one site  may  be vastly different than for
the same method applied at  another  site,  especially
when transportation  costs  are involved.  Costs  for
off-site  disposal would include transportation  as well
as disposal costs, and all but in situ options must take
into account  excavation costs  for the contaminated
materials. Those disposal  methods  requiring waste
treatment will  involve  treatment costs as well.

Despite  the  limitations and cautions,  some  typical
costs of disposal methods are presented in Table 4.
These costs are  not  intended to be applicable to  any
particular site. Costs of returning  "clean"  treated
material to a site  are not included.
                                                    12

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                 Table 4. Typical Costs of Various Disposal Methods*
                 These costs are presented to give some typical costs under the referenced conditions. They are not
                 intended to be applicable to any particular site. Costs of returning "clean" treated material to a site
                 are not included.
Remediation Method
Capping with claya
Vertical barrier slurry
wallb
Grout curtain0
Costing Units
cu m
sq m
cu m
Materials &
Installation"
$13-200
$33-377
$208-403
First Year
O&M"
$0.44
Comments
Area units for
vertical face
Cost for grouted
soil volume
                  Excavation and secure         cu m
                  land encapsulation01
                  Land spreading
                  New underground            cu m
                  mine6
 $276-895
$.045
No data found
 $399-942     $2.50-18.00
Existing underground
mine6
Ocean disposal*
cu m
cu m
$185-523
$332-401
$2.50-18.00 -
                 * Costs are mid 1980s. Costs are from different sources and may be derived from different
                  assumptions and therefore may not be directly comparable.
                 a Low cost includes cost of capping only [11]. The material consists of radiation residues from
                  uranium processing and contaminated soil. The high cost includes cost of excavation,
                  transportation, and legal assistance. Cost for site acquisition is not included. The material consists
                  of contaminated soils.
                 b Low costs are for soft soil with 9m depth of excavation, and the high costs are for hard soil with
                  37m depth of excavation [3,9], These costs are for hazardous waste. Specific soil conditions have
                  not been identified.
                 c Low costs are for Portland cement grout and high costs are for 40% sodium silicate grout in rocky
                  soil [9]. These costs are for hazardous waste; the specific soil conditions have not been identified.
                 d Low cost includes cost of excavation and transportation, but does not include  cost for disposal site
                  acquisition [1]. Transportation costs are from Montclair/West Orange and Glen Ridge to a land
                  encapsulation cell in Glen Ridge. High cost includes cost of transportation and excavation, etc., but
                  does not include cost of disposal site acquisition.  Transportation cost is from Niagara Falls, NY to
                  Hanford, WA [11],
                 6 Costs are for storage of nonradioactive hazardous waste. Specific conditions could not be identified
                  [15].
                 ' Low cost includes cost of excavation and transportation to ocean dump site off New Jersey/New
                  York shore [11]. High cost includes cost of excavation and transportation to an undetermined
                  ocean dump site [1]. Material is radiologically contaminated soil.
2.5  References

1.  Camp,  Dresser  &  McKee et  al.  Draft  Final
    Feasibility Study for the  Montclair/West Orange
    and Glen  Ridge,  New Jersey  Radium  Sites,
    Volume  1. USEPA Contract  68-01-6939,  1985.

2.  Lutton,   R.  J.  Design.   Construction,  and
    Maintenance  of  Cover  Systems  for  Hazardous
    Waste:  An  Engineering  Guidance  Document
    EPA-600/2-87-039  Hazardous  Waste Engin-
    eering  Research  Laboratory,  Cincinnati,  OH,
    1987.

3.  McAneny, C.  C.,  P. G. Tucker,  J. M. Morgan, C.
    R. Lee,  M. F.  Kelley, and  R. C. Horz.  Covers  for
    Uncontrolled  Hazardous   Waste  Sites.  EPA-
    540/2-85-002,   Office  of  Emergency  and
    Remedial Response,  Washington,  DC,  1985.
 4.  Lutton,  R.  J.,  G.  L.  Regan, and  L.  W.  Jones.
     Design  and  Construction of  Covers  for  Solid
     Waste  Landfills.  EPA-600/2-79-165,  Municipal
     Environmental  Research  Laboratory,  Cincinnati,
     OH, 1979.
 5.  Lutton, R. J. Evaluating Cover Systems for  Solid
     and  Hazardous  Waste.   SW-867,   USEPA,
     Municipal  Environmental  Research  Laboratory,
     Cincinnati, OH, 1980.
 6.  Combined  NRC-EPA  Siting   Guidelines  for
     Disposal  of  Commercial  Mixed  Low-Level
     Radioactive and Hazardous Wastes, 1987.
                                                       13

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7.  Joint  NRC-EPA Guidance on  a Conceptual
   Design Approach  for Commercial Mixed  Low-
   Level  Radioactive and Hazardous Waste Disposal
   Facilities, 1987.

8.  U.S.  Environmental  Protection  Agency.  Slurry
   Trench  Construction  for  Pollution   Migration
   Control.  EPA  540/2-84-001,  Municipal
   Environmental  Research  Laboratory,  Cincinnati,
   OH, 1984.

9.  U.S. Environmental Protection Agency.  Handbook
   -  Remedial  Action  at  Waste  Disposal Sites
   (Revised).  EPA-625/6-85/006, Hazardous
   Waste  Engineering  Research  Laboratory,
   Cincinnati, OH, 1985.

10. U.S. Environmental Protection Agency. Technical
   Resource Documents on  Hazardous Waste Land
   Disposal. SW860  and SW870 Series. Office of
   Solid  Waste, Washington,  DC, 1979-1987.

11. U.S.  Department  of  Energy.   Long  Term
   Management of the Existing Radioactive  Wastes
   and Residues at the Niagara Falls Storage Site,
   DOE/EIS-0109D, Washington, DC,  1984.

12. Gilbert, T. L., J. M. Peterson, R. W. Vocke, and
   J. K.  Alexander. Alternatives for Management of
   Wastes Generated by the Formerly Utilized Sites
   Remedial Action Program.  ANL/EIS-20, Argonne
   National Laboratory, Argonne, IL, 1983.
13. Stone, R. B., P. L. Aamodt, M. R.  Engler, and P.
   Madden.  Evaluation  of  Hazardous  Wastes
   Emplacement  in  Mined Openings.  EPA-600/2-
   75-040.  Municipal  Environmental  Research
   Laboratory, Cincinnati, OH, 1975.

14. Stone,  R.  B.,  K.  A.  Covell, T. R.  Moran, L. W.
   Weyand,  and  C.  U. Sparkman.  Using  Mined
   Space   for   Long-Term   Retention  of
   Nonradioactive Hazardous Waste.  EPA-600/2-
   85-021,   Hazardous  Waste   Engineering
   Research Laboratory, Cincinnati, OH, 1985.

15. Esposito,  M.  P.,  W.  E.  Thompson,  and J.  S.
   Greber.  Using  Mined  Space  for  Long-Term
   Placement of  Dioxin-Contammated  Soils. EPA
   Contract  68-02-3693, 1985.

16. Jacoby,  C. H.  Inspection Visit of the Hazardous
   Waste  Storage at Herfa-Neurode,  Germany, of
   Kali &  Salz.  Prepared for EPA  under Bechtel
   Subcontract. 1977.

17. Council  on   Environmental   Quality.  Ocean
   Dumping  - A National Policy. A  Report  to the
   President.  U.S. Government Printing Office, 1970.
                                               14

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                                              Chapters
                                        On-Site Treatment
3.1  Introduction
This  chapter discusses on-site  treatment  tech-
nologies  that  may   immobilize  radioactive
contaminants. These technologies include:

       stabilization or solidification
       vitrification

These technologies do not reduce the amount of the
contaminated material. However, they  immobilize the
contamination in  the waste  material  and  limit  the
spread of radioactive material.

Each of these is discussed below. The  state  of the art
of these on-site treatment technologies  is shown in
Table 5.

3.2  Technologies of Potential  Interest

3.2.1    Stabilization or Solidification

3.2.1.1   Description and Development Status
Solidification  is  a  process that produces  a monolithic
block of waste  with high structural  integrity.  The
contaminants do  not interact  chemically  with  the
solidification agents but are mechanically bonded. A
stabilization  process usually  involves  addition  of
reagents, which limit the solubility or mobility of the
waste  constituents.  Solidification  and  stabilization
techniques  are often used together [1].

The  intent  of solidification and/or stabilization of the
contaminated soil  materials would be to  limit  the
spread of radioactive  material via leaching,  etc., and
to trap  and contain radon within  the densified  soil
mass. While the contaminants would not  be  removed
and  would  remain  active,  the  mobility  of the
contaminants would be eliminated or reduced.

Waste materials at Superfund sites could  be  solidified
in two ways. One  is to inject the solidifying agent into
the materials in place.  The other  is to  dig up  the
materials and machine-mix them  with  the solidifying
agent. The  solidified materials from the latter process
could then be  re-deposited  on  or  off site  in
engineered  containment systems [1,2].

In  in  situ  solidification  utilizing  grout  injection
technology,  grout would be injected  directly into the
soil containing  the  radioactive  source   materials
(Figure 7).  This  technique has been  proposed  by
DOE  for by-product  radioactive  wastes  [3].  If
successful,  the  materials  would be  solidified  and
radon  would be contained long enough to decay to its
daughters. The solidified  material also  might reduce
mobility  of   radioactive   and  nonradioactive
constituents;  if  not,  the material  would require
isolation.  The solidification technique thus  might be
better suited  to materials that  are  already buried
and/or capped.

In  situ grouting  for  stabilization purposes  requires
extensive and  detailed  characterization  of  the  waste
matrix before the process  is undertaken [Oak  Ridge
National laboratories,  staff, personal  communications,
May 19,  1987]. Chemical grouts are better suited to
fine-grained  soil  with  small   pores, while cement
grouts are best for coarse-grained materials. Greater
effectiveness might  be achieved if  both techniques
are used  together: cement grouting  first, followed by
chemical  grouting.  Lime  and  fly   ash have   been
injected together to  stabilize  abandoned solid  waste
sites [4].

The second way to solidify the waste materials is to
excavate and mix the waste with solidifying  agents in
either  a  continuous  or batch  process  [4].  Portland
cement,  pozzolanic fly  ash, or any  of  a number of
chemical fixation agents can be used in  the process.
Bitumen  (asphalt), because of its  excellent binding
and sealing  properties, and its weatherabihty, can be
an effective  solidifying agent.

Excavation and  mixing  would  be followed  either by
placing the solidified  soil in containers or by burial on
the site.  The  use of containers provides greater
assurance against release of radioactive  materials and
allows for flexible storage,  either  on- or  off-site.
On-site burial  with   or  without containers would
require a  soil cover of sufficient thickness  to absorb
the gamma radiation.
                                                  15

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Table 5.  State of the Art of On-Site Treatment Technologies
                                                     Field
                                                 Demonstration  Pathologically
                                    Bench  Pilot       with      Contaminated
                          Laboratory  Scale  Plant   Radioactive      Site
	Technology	Testing   Testing Testing     Material     Remediation
                               Remarks
 Stabilization or solidification

 Vitrification
                  Proposed by DOE for low-level radioactive
                  waste
                  Field testing by ORNL
Figure 7.   Subsurface injection machine. (Reprinted from
           [3].)
3.2.1.2   Potential Applicable Situations
Solidification could be considered  for use in a variety
of situations. It offers  the opportunity of leaving the
waste  materials  on-site in a  relatively  immobilized
state. It could  be applied to materials with a range of
physical  characteristics, and is particularly  applicable
to  highly  porous  and  permeable  matrices.
Solidification may be useful where increased material
strength  is desired,  such as in a matrix of municipal
solid waste.

For residential sites, the in  situ method may not be
suitable,  since  maintenance  of utilities  would  be
difficult.  Also,  it probably  is  insufficient  to  reduce
gamma radiation exposure substantially.

The injection solidification technique is best suited to
materials that are already buried and/or capped and
may provide  more  security  against  the  escape  of
radioactive material entering the environment.


3.2.1.3   Advantages and Disadvantages
Advantages - Solidification may be able to  reduce  the
release  of  radon  and  associated radioactivity  to
acceptable levels at the  waste site without  removal of
materials for off-site containment.

Solidification may  also  facilitate transportation  and
off-site disposal of radioactive contaminants  with  the
use of containers, especially where volume reduction
or  extraction  techniques  have  been  applied
previously.

Disadvantages -  While solidification  may  work
initially,  its  long-term effectiveness  is  not  known.
Working  against the  in  situ solidification  technique
may  be  the  location  and  configuration  of the
contaminated  masses. If they are thin, discontinuous,
and  at or near  the  surface, injection grouting would
obviously  face  significant  difficulties.  In  situ
solidification  would  be  impractical  for  residential
areas.  In situ  solidification, as with other  disposal
technologies, may trap the radioactivity, but does  not
eliminate  it.  If other types of  hazardous  waste  are
included  in  the waste,  they  may  interfere with  the
solidification  process. Organic chemicals  could  be
particularly  troublesome  and   could  eliminate
solidification  processes  from  further  consideration.
Excavation coupled with solidification  may be  more
costly than excavating and land encapsulation.
3.2.1.4
Information Needs
Before  a decision  can  be  made  concerning the
usefulness  of the  process  for the  site  being
considered, detailed  information on the  matrix  (e.g.,
                                                    16

-------
soil) and  associated  waste characteristics  must  be
known.
3.2.2    Vitrification

3.2.2.1   Description and Development Status
Vitrification is  a process in which  the  contaminated
material is heated to  its melting temperature,  then  is
allowed to cool and  solidify to a glassy mass. In the
sintering process the  contaminated  material  is heated
to produce a coherent  mass  without  melting.  The
process may be applied in situ or it  may be applied  to
material excavated and transported to a fixed process
site.

The  in   situ  vitrification  process  has  been
experimentally  applied to  soils by  Battelle  Pacific
Northwest  Laboratories  [5]  with  the  intent   of
potentially applying it to radioactive waste sites and/or
Superfund hazardous  waste sites.  The concept  is
depicted in Figure 8.  Presumably,  the radionuclides
would  be  trapped, and  some  radiation  would  be
attenuated by the resulting material.

Figure 8.   In situ vitrification process. (Reprinted from [5].)
 U    Off Gas Hood
        I
Vitrification is  a high energy consuming process. In
the in situ vitrification process, electricity is applied to
electrodes placed in  the ground over the waste mass.
The ground  and waste mass heat and  melt, and the
melting  zone  grows downward. A hood  to  catch
gases is placed over the  zone,  and the gases are
treated or removed to prevent air pollution.

In the full-scale concept, electrode  spacing  would be
3.5 to 5 m, and the power required  would be  3750
kW, for  an expected  vitrified mass of 400 to 800 tons
[5].

An in situ  pilot-scale experiment was  completed in
the summer of 1987 at ORNL on natural soil spiked
with cesium and strontium to simulate the radioactive
contaminants.  Results of this experiment are  under
evaluation. In July 1987 an in situ vitrification process
was field demonstrated on a transuranic waste site at
Hanford, Washington.   The  results  of this  field
demonstration are being  evaluated  [Battelle
Northwest Laboratories,  Personal  Communication,
February 1988; and ORNL,  Personal  Communication,
May 17, 1987].

The  vitrification  also  could  be  performed  on
excavated materials  on site or off  site in  an electric
furnace or  in  a rotary kiln  [6].  In the  first, the
materials would be melted and poured into molds.  In
the second, the contaminated  materials are sintered
in a rotary kiln. While sintering may not necessarily
produce  a  solid monolithic mass,  it may  reduce
availability of the radioactive constituent for leaching
and  therefore  may be appropriate  for containing the
radioactivity.

The products  in either case are likely to  require an
engineered final disposal method.


3.2.2.2   Potential Applicable Situations
The in situ  vitrification process  has  been  developed
specifically  for  application  to  low-level  radioactive
waste  sites, particularly  to  be used by DOE  in its
remediation  programs. In  situ  vitrification works on a
variety of materials to a limited extent.

The effectiveness  of the process is very different for
different  radionuclides and  different  chemicals.  The
volatility and mobility of the element or compound are
important factors in the applicability  of the method.


3.2.2.3  Advantages and Disadvantages
Advantages  - In in situ  vitrification the materials do
not require excavation; the process could  be applied
to materials  with  minimal prior  preparation.  The
radioactive material is trapped in  the vitrified  mass,
and releases to the environment are reduced.

Electric furnace vitrification on excavated  material
would produce a glassy mass, which can  be poured
into  molds  of  some convenient  size.  The glassy
blocks  might  supplant  waste  containers  or
solidification  blocks.  Such treatment might be  a
preprocessing  step to mine or ocean disposal.  The
rotary kiln is significantly more  energy-efficient than
the electric furnace.

Disadvantages -  Many  substances  would  probably
volatilize  in the process, requiring  gas collection and
treatment  devices.  Radon trapped in  the  material
matrix  could be released  during  the process,  and
radium may volatilize. The use  of  the process in
residential  areas  may pose difficulties,   including
problems  in future underground utility repair work.
Even if this were  to be  successful, the vitrified
material will remain  radioactive. Additional shielding
may be required for protection from gamma radiation.
The  vitrified material,  if  near  the   surface, may still
require removal from residential areas.
                                                   17

-------
Fixed plant  vitrification  on or off  site would require
excavation and transport of the waste materials to the
vitrification site.  This would  add  to the  cost.  The
rotary kiln may not be suitable for  radioactive wastes,
as it  does not produce a  secure,  solid,  monolithic
mass.

3.2.2.4   Information Needs
Detailed  waste  characterization  will likely  not be
required  to  make the  process  work. However,  the
characteristics of the materials, including  the matrix
and  the  contaminants,  need  to be  known  in  some
detail  in order  to  determine  the volatilization
characteristics, so that  control of off-gases may be
planned correctly.

3.3  Typical Costs  of On-Site Treatment
     Technologies
The  cost of  the  application of any  of the treatment
technologies described  in this section will  depend on
many factors, including  waste  and  site characteristics.
Thus, the costs cannot be estimated reliably for  any
technology and  for  any site  at this stage,  because
most of the  prerequisite information  is not available.  It
also must be cautioned  that many, if not most, of the
controlling factors will be site-specific.

Despite  the  limitations  and cautions,  some  typical
costs for treatment  technologies  that immobilize the
radioactive  contaminants are  presented  in  Table
6.These costs are not  intended to  be applicable to
any particular site.
3.4  References

 1.  U.S. Environmental Protection Agency. Handbook
    - Remedial   Action at  Waste Disposal Sites
    (Revised).  EPA-625/6-85-006,    Hazardous
    Waste  Engineering  Research   Laboratory,
    Cincinnati,  OH,  1985.
2.   U.S. Environmental Protection Agency. Handbook
    - Remedial  Action at Waste Disposal Sites. EPA
    625/6-82-006,  1982.
3.   Tamura, T., and W.J. Boegly, Jr. In Situ Grouting
    of  Uranium Mill Tailings Piles: An Assessment.
    ORNL/TM-8539,     Oak  Ridge   National
    Laboratory, Oak  Ridge,  TN,  1983.
4.   Blacklock, J. R., and P. J. Wright.  Stabilization of
    Landfills, Railroad Beds and  Earth Embankment
    by  Pressure  Injection of  Lime/Fly Ash Slurry.
    Proceedings -  Ash  Tech    84,   Second Inter-
    national  Conference on Ash  Technology  and
    Marketing,  London, England, 1984.
5.   Fitzpatrick, V. F., J. L.  Buelt, K. H. Oma, and  C.
    L. Timmerman.  In Situ  Vitrification   -  A Potential
    Remedial   Action  Technique  for  Hazardous
    Wastes.  Proceedings  of  the    Fifth  National
    Conference  on  Management  of   Uncontrolled
    Hazardous Waste Sites, Washington, DC,  1984.
6.   Camp,  Dresser &   McKee  et  al.  Draft  Final
    Feasibility Study  for the Montclair/West  Orange
    and  Glen  Ridge,  New Jersey   Radium Sites,
    Volume 1. USEPA Contract 68-01-6939,  1985.
7.   U.S.   Department  of  Energy.   Long  Term
    Management of  the   Existing  Radioactive  Wastes
    and Residues at the Niagara  Falls Storage Site,
    DOE/EIS-0109D, Washington, DC,  1984.
                          Table 6. Typical Costs of On-Site Treatment Technologies*

                            These costs are presented to give some costs under the referenced
                            conditions. They are not intended to be applicable to any particular
                            site. Costs of returning  "clean" treated material to  a site are not
                            included. Costs are mid 1980s.
Treatment
Technologies
Stabilization/
solidification
(chemical fixation)3
In situ vitrification b
On-site
vitrification c
Costing Units


ton
cu m

-
Materials &
Installation*


S 33 - 248
$161 - 224

$400 - 600
                           * Costs are from different sources and may be derived from different
                            assumptions and therefore may not be directly comparable.
                           a Costs provided are for hazardous waste [1]. Specific soil conditions
                            could not be determined. Low costs are  for in situ mixing;  high costs
                            are for in-drum mixing. The solidification agent is silicate and
                            cement. The cost includes labor, equipment and material.
                           b These are typical estimated costs for hazardous waste [1]. Soil
                            moisture and electricity cost can increase the cost. Specific soil
                            conditions have not been identified..
                           c Cost includes  excavation and on-site vitrification, but does not
                            include cost for disposal of slag [7]. The material is radioactive
                            residue from uranium ore processing. Cost increases with increasing
                            moisture and electricity cost.
                                                    18

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                                             Chapter 4
                                          Radon Control
4.1  Introduction
Although  the  main  intent  of  this  report is  to
summarize technologies  that might be used  to
remove, contain, or immobilize the radioactive source
materials in Superfund sites,  where radioactivity has
resulted from material processing or waste disposal
operations, there may be  sites  where  it  is more
desirable or logical not to  disturb these materials,  at
least for an interim period.

Control processes using ventilation are already used
to some  extent to lower the  radon concentration  in
residences contaminated  with naturally  occurring
radon. Radon control from  soil can  be  approached in
three ways: (1) radon reduction in homes through soil
gas ventilation;  (2)  electrostatic  precipitator  control;
and  (3) areal ventilation  from the soil  above the
contaminated  source mass.  Each  of  these  is
discussed below. Table 7 shows  the state of the art
of radon control technologies.

4.2  Methods

4.2.7    Radon Control and  Reduction in
        Buildings

4.2.1.1  Description and  Development Status
Radon   may  accumulate  to   unacceptable
concentrations indoors. EPA  has provided guidance
that recommends action at levels above  0.02 WL  (4
pCi/l)  to  reduce  annual average  exposure to below
those levels. Note in Table 8 that the average indoor
concentration  is estimated  to be 0.005 WL. Although
exposures between  0.005  and 0.02 WL do  present
Table 7. State of the Art of Radon Control Technologies
                      some risk of lung  cancer, reductions  of these levels
                      may be difficult and sometimes impossible.

                      EPA has developed and implemented a program to
                      evaluate  various  methods   to  reduce  radon
                      concentrations  in  residences  [1].  The  program is
                      aimed  at  developing  cost-effective technologies  for
                      reducing radon  from  naturally  occurring sources in
                      existing and new homes of all  structural types.  The
                      first  demonstration  projects  are underway  in homes
                      located in  Pennsylvania,  New  York,  New Jersey,
                      Maryland, Tennessee, Alabama, and Ohio.

                      Radon reduction in homes is simple in concept.  The
                      EPA program recognizes three basic methods:

                          (1)  diversion  of soil gas flow away  from  the
                              house;
                          (2)  barriers to prevent entry to the house; and
                          (3)  reduction of concentration once it has entered
                              the house.

                      The  techniques that may be used to implement these
                      methods  are  described  in   reference  2.  The
                      techniques  include  sealing entry  cracks  in
                      foundations, forced ventilation of soil in  and adjacent
                      to the foundation, and natural and forced ventilation of
                      the  airspace inside the  house.  Examples  of  the
                      techniques that may be used are depicted in Figures
                      9 and  10. However, each house must be addressed
                      individually.

                      A  variety  of  soil  parameters  influence radon
                      movement,  including  thickness, densities,  specific
                      gravities,  permeabilities,  porosities,  and  moisture
   Technology   Laboratory Testing
Bench Scale
  Testing
Pilot Plant
 Testing
Field Demonstration
 with Radioactive
     Material
  Radiologicaliy
Contaminated Site
  Remediation
Remarks
 Radon Control
    in homes

    ESP control

    areal control
                                                            Requires
                                                            maintenance
                                                            Requires
                                                            maintenance
                                                            Requires
                                                            maintenance
                                                 19

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Table 8. Representative Exposure to Radon-222 Progeny
     Location         Average WL*	Average pCi/r
 Outdoors
 Indoors
0.001
0.005
0.2
1.0
" WL =  Working Level = a measure of exposure rate to radon
       progeny. Under equilibrium conditions of radon and its
       progeny, 1 WL equals the activity of 100 pCi/l of air.  At
       the equilibrium (50%) generally considered representative
       of most indoor environments, 1  WL equals 200 pCi/l [2].

content. These parameters in turn affect the diffusion
and emanation coefficients of radon [3].
4.2.1.2  Potential Applicable Situations
Site-specific house remediation  techniques for radon
levels  are  currently  being  demonstrated.  The
techniques  apply to radon  emanating  from  the
underlying soil, whether the  source  is natural  or  a
man-made  waste  mass.   Radon   control from
buildings may be a viable  interim technique while
considering  and  implementing  source  removal
alternatives.


4.2.1.3  Advantages and Disadvantages
Advantages - Radon reduction techniques for existing
homes  can  be  simple,  effective,  and  relatively
inexpensive.  They may be temporary alternatives
while awaiting removal of the source  radionuchdes, if
this is being considered. However, in many instances,
the solutions can be relatively difficult and expensive
when the problem is  not completely  understood.
Costs can run into thousands of dollars for a house if
90 + percent  reductions are needed,  especially for
large highly-finished houses  with  poor  sub-slab
permeability.

Disadvantages - Radon reduction  techniques do not
affect the source of the radon,  and  therefore radon
production at current  rates can be expected to
continue indefinitely. Thus, the reduction system must
be maintained for as long  as the building  is occupied
or the source is present. Radon removal  systems do
not  address  gamma radiation   problems,  potential
ingestion  pathways,  or  the potential  for  unearthing
existing contaminated material.


4.2.1.4   Information Needs
Information   needs  include the  levels of  radon
concentration  inside  the structure,  an  inventory of all
the avenues of radon entry, the characteristics of the
soil  underlying  the building,   and   the  structural
characteristics of the building.
4.2.2    Electrostatic Precipitators (ESPs)

4.2.2.1  Description and Development Status
Electrostatic precipitators (ESPs) are a form of indoor
air cleaner.  ESPs work  on the principle that  when
particles suspended  in  air enter an electrostatic field
they become charged and migrate under the action of
the field  to  the positive  electrode,  where they  are
collected.  The  collected  material  is  removed  by
rapping the  collecting  surface  to  slough  off  the
particles. An ESP would be installed in a room or area
so as  to  maximize  the  air contact.  The  ESP may
reduce the number of particles  (e.g. dust and smoke)
to which radon progeny may be attached, resulting in
a reduction  of radon progeny  in  the air.  The  health
effects of  using ESPs in reducing  radon  progeny are
not known.
                               4.2.2.2  Potential Applicable Situations
                               ESPs  have been used to reduce the radon progeny
                               levels  in a store built with contaminated adobe bricks
                               [4]. The technique could  be applied for buildings
                               where  the source of  contamination  is  building
                               materials or the underlying soil.


                               4.2.2.3  Advantages  and Disadvantages
                               Advantages - ESPs are easy to install in rooms or
                               enclosed areas.

                               Disadvantages - ESPs do not affect the source of
                               the radon. The reduction system must be  maintained
                               for as long as the building is  occupied or  the source
                               is present. The ESPs do not reduce gamma radiation.
                               The health effects of using ESPs are not known.


                               4.2.2.4  Information  Needs
                               Information needs  include  the  level  of  radon  and
                               radon  progeny  concentrations  inside  the room or
                               area; the structural characteristics of the building; and
                               air flow, volume, and pattern.


                               4.2.3    Soil Gas Venting and Areal Control

                               4.2.3.1  Description  and Development Status
                               The term  "soil gas  venting,"  as  used in this  section,
                               refers to techniques that may be applied  across the
                               entire area of gas production. For  example,  the gas
                               extraction  that  is  now relatively  common  in  and
                               around  municipal  solid waste  landfills  fits in  this
                               category.

                               Soil gas venting has  been  used to remove methane
                               from municipal waste  landfills and to remove organic
                               vapors from  underground   leaks  of  organic
                               compounds.  Both  active  systems, where a  fan  or
                               pump  is  used to  induce gas  flow, and  passive
                                                  20

-------
Figure 9.    Tile ventilation where tile drains to sump. (Reprinted from [2].
                            Exhaust
              Outside
              fan
              (option)
          Close major
          openings m walls
                  Optional
                  piping
                  configuration
                      Iv^OT^v*1,
                      '  'tf\S?'^:L'-::'  '
                    Aggregate
                                                                 To exhaust fan
                                                                 mounted in attic
                                                                 or on roof
                               Notes:
                               1. Closure of major
                                 slab openings is
                                 important
                               2 Closure of major
                                 wall openings might
                                 also be important
                                   Suction
                                  pipe


                                  - Bracket
                                   (option)
                                                                          Sealant.
                                  &y*5S&3E4S
                                  ***4>*<-.. o*V  . LV
   .,'<*.  r&'
.A*. J^^.-xrl^
                                       Existing dram tile
                                       circling the house
                                                                                    Drain pipe
                                                                                    (to discharge)

                                                                                   Masonry bolts
                                                                                    Sealant
;,.*&<. M.
J.a.'*?'   W
                                                   21

-------
Figure 10.    Sub-slab ventilation. (Reprinted from [2].)
                                  Exhaust (preferably
                                          released above
                                          eaves)
                 Outside
                 fan
                 (option)
                Optional
                piping
                configuration
To exhaust fan
mounted in attic
or on roof
                     Close major mortar
                     cracks and holes in
                     wall2
                                                                                                  Connection to other
                                                                                                  suction points
  Notes
  1  Closure of major slab
     openings (e g , major settling
     cracks, utility penetrations,
     gaps at the wall/floor joint)
     is important
  2  Closure of major wall
     openings might also be
     important
                                                                                          House air through unclosed
                                                                                          settling cracks, cold joints,
                                                                                          utility openings
                                                                                         Open hole
                                                                                         (as large as
                                                                                         reasonably
                                                                                         practical)
                                                             22

-------
systems, which  rely on the natural flow,  have been
used to vent soil  gases.  These  types  of  systems
might be applied to vent radon from soils where radon
diffusion and migration occur.

In landfill soil gas venting, a narrow perforated pipe is
installed in  the  center  of the extraction well  and
backfilled with coarse rock. The upper part of the well
is sealed around the pipe with impervious material to
prevent air from  being pulled into the  well, as  shown
in Figure 11. The perforated pipe  is connected  to a
header  system  and fan  to  extract  the gas.  Gas
withdrawal  rates  vary  widely from site  to  site
depending on the rate of methane and carbon dioxide
generation and the landfill's porosity [5].

Figure 11.    Gas extraction well for  landfill  gas control.
            (Reprinted from [4.)
                            Gas Flare

                            Exhaust Blower


                            Impervious Backfill

                             Perforated Pipe
       Gas Flow
                             Gas Flow
                             Permeable Material
Based on the  same general principle, Terra Vac has
successfully removed volatile organics from the soil at
several sites in the United States. Terra Vac utilizes a
vacuum pump to apply vacuum  to the soil through
wells,  causing  an in situ air  stripping of  volatile
organic  compounds.  The  extracted gases  are
discharged to  the atmosphere  through  an  activated
carbon bed which adsorbs most volatile  organics [6].

If  used for radon removal,  direct  venting  to the
atmosphere may be appropriate. In some cases, the
highly concentrated radon in the vented gas may be
of such quantity  that it cannot be released  to the air
immediately. In this  case, the  gas  can be  passed
through a packed bed of  activated carbon. Since soil
gas tends to be  saturated with  moisture (1  - 2% by
volume)  the  retention capacity  of  the carbon is
somewhat  reduced. At 20C, activated carbon  can
adsorb 5000 to  9000  cc  of radon-bearing air per
gram  of  carbon  depending  on  the type of carbon,
temperature, and flow rates [7]. However, over years
this could cause  the carbon  to  become a  low-level
radioactive waste.
 Active soil  gas venting has  also been  applied to
 remove  organic vapors from  soil.  In  this remedial
 technology, soil gas is drawn  from  a well  or set of
 wells constructed near one edge of the contaminated
 zone. To better induce the flow of vapor and to dilute
 the vapors, another well or set  of wells is constructed
 on the opposite edge of the zone. By drawing air from
 one  set of wells, a flow gradient is established across
 the contaminated zone, and vapors are drawn off [8].

 Another  type of active gas ventilation system,  which
 relies upon  pumping air into  the soil at one location
 and  pumping gases out at another location, may be
 more effective  than other methods [9]. Figure 12 is a
 schematic diagram of this system.

 Passive  soil  vent  systems are relatively simple  and
 inexpensive to  construct and operate.  However, they
 may  be less  effective  than  active systems in
 removing soil gas  since much  less gas flow occurs.
 The  passive flow  would be caused  by  barometric
 pressure changes  and diurnal  temperature changes
 that  affect soil gas  movement.

 The  effectiveness of any soil radon removal system is
 likely to  be very site-specific,  depending  largely on
 the  porosity  of the  soil,  soil  moisture content,  the
 distribution  of  radium  in   the  soil,   and   the
 chemical/physical matrix containing  the radium.  For
 example, if the radium  were  contained in a tightly
 compacted and/or wet matrix,  the radon  would  not
 diffuse readily  and probably would  remain  trapped
 until  it decayed  to its progeny.  It should be  noted  that
 radon should not be removed from soil gas unless  it
 is a  proven source of  indoor radon for an  on-site or
 a  nearby occupied structure.  Radon  in subsurface
 soil,  unlike  methane,  presents no fire or  explosion
 potential.

 Even  though   soil  gas  venting   is  a  popular
 methodology   for   dealing  with  volatile  organic
 chemicals (VOC) in the  soil and/or  ground water,  it
 has  some  large  potential  problems in radioactive
 applications. This method has  been shown to  be in
 violation  of some State radiation emission standards,
 and  charcoal beds may collect  more  than  exempt
 quantities of radon  decay products,  making  them
 hcensable  or  registerable  under  State  radiation
 statutes.  Moreover, when these  charcoal  beds  are
 incinerated  to  remove  the VOC,  they may impact
 Department  of  Transportation  (DOT) regulations for
 radioactive materials  (transport to  out-of-state
 incinerator) and  may impact a  second  state's
 radionuclide emission standards (at the incinerator).


 4.2.3.2   Potential  Applicable Situations
 Radon gas  venting  from a radioactive waste  site
could be applied  where  the   materials are  highly
porous (high permeability) and the radon could move
freely to  the extraction point. Sweden has  used  soil
                                                  23

-------
 Figure 12.   Schematic diagram of a forced air venting system. (Reprinted from [9], Courtesy of American Petroleum Institute).
o
CN
o
CO
o
JZ
Q.
0)
Q
            Air Inlet
             Well
                    Velocity
                  Pressure Head
               Sample
                 Port
              2" PVC
               Pipe
            Vapor
           Recovery.	f
Ground Surface  Well /I  J-
              Velocity
                Port
              Stand Pipe
                2" ID
  Magnehehc Differential
     Pressure Gauge
 Static
Pressure   ^Vacuum
 Head    V Gau9e    PVC Pipe
                ^"Schedule 40
Vacuum Pump
                                           r=? _fCZI*r
                                          r\rrr
                                           Standard Reducer
                                             Pitot
                                                        Vacuum Pump
                                                                             Temporary
                                                                          -. Electrical Power
                                                                          I  220V, 3 Phase
                                                       Flow
                                                      Control
                                                       Valve
                                       Water Recirculation
                                          Line to Vacuum
                                Solenoid    Pump Suction
                                 Valve
                       2" Schedule 40 PVC
                          Well Screen
                          Perforation
                   1    from 14'to 20'
                                      4" Bore
                                        Hole
 gas venting  for radon  removal in small areas  for
 venting naturally occurring radon.


 4.2.3.3  Advantages and Disadvantages
 Advantages -  Radon  venting  might  supplant  other
 remediation techniques.  The  entire operation  could
 take place on the  site without disturbing surrounding
 properties. It may be relatively low m cost.

 Disadvantages -  The radionuclide source material
 would  remain in place. As long as  it does, the  radon
 removal system would have to operate, since  radon
 would  be  produced indefinitely.  The  system  would
 require a long-term maintenance  program.

 The soil, if it is not totally uniform and highly porous,
 would  probably  not be vented  uniformly.  Also,
 absence of sufficient data on this  approach makes it
 somewhat  unpredictable. This  method does  not
 address gamma  radiation.  Adsorbing  radon onto
 carbon in large quantities may  be unworkable.  Areas
 with a high water table may generate large quantities
 of  radioactively contaminated  ground  water,  which
 must be treated and/or disposed.
                                     4.2.3.4   Information Needs
                                     The waste  site  would  require detailed  physical
                                     characterization  in  order  to determine if  the areal
                                     venting concept is practical and feasible.

                                     4.3 Typical Costs of Radon Controls

                                     Rough estimates of  costs  are  provided  in  "Radon
                                     Reduction  Techniques  for  Detached  Houses  -
                                     Technical Guidance"  [2] for various radon reduction
                                     techniques for  residences.  The  cost  estimates  are
                                     based upon the  experience  of EPA and a number of
                                     investigators. A summary of these rough estimates is
                                     included  in Table 9.

                                     Typical  capital  costs for soil  gas venting systems
                                     range from  $10  -  $12  per cu  m  for  shallow VOC
                                     deposits  (at less than 20 feet)  [10].  The cost includes
                                     site preparation,  drilling, piping,  blowers, electricals,
                                     decontamination and demobilization.  The  typical
                                     operating cost for a soil gas venting system is $12 -
                                     $14/cu  m/yr. The  operating  cost  includes cost of
                                     electricity, carbon, water, and labor.
                                                   24

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                Table 9. Typical Costs of Various Radon Reduction Techniques in Existing Homes [2]
Reduction Technique Operating
Natural ventilation
Forced ventilation

Forced ventilation with heat
recovery
Avoidance of appliance
depressunzation
Sump ventilation



Sealing entry routes
Drain tile ventilation

Active wall ventilation
Sub-slab ventilation
Installation Cost ($)
0
50-1000

800-2500

100-300 (install ducts)

800-2500
(contractor-mstallated)
300
(home owner-installed)
300-500*
700-1500 (contractor)
300 (home owner)
1500-250
900-2500
Annual Cost ($)
1.1 to 3 x normal heating cost
1 1 to 3 x normal heating cost
+ $275/yr for electricity
1.1 to 2.0 x normal heating
cost + $30/yr for electricity
small

$130/yr



low
$130/yr$

$230-460/yr$
$130/yr$
                * For average sealing. A comprehensive sealing job would run much higher.
4.4  References

1.  U.S. Environmental Protection Agency.  Report to
    Congress on  Radon Mitigation  Demonstration
    Programs under Section 118(k)  of the Superfund
    Amendments and  Reauthorization  Act of 1986,
    1987.

2.  U.S.  Environmental  Protection  Agency.  Radon
    Reduction  Techniques for Detached  Houses -
    Technical  Guidance.  Second  Edition  EPA-
    625/5-87-019.  Office  of  Research  and
    Development, Washington, DC, 1987.

3.  Nuclear  Regulatory  Commission.  Calculation  of
    Radon Flux Attenuation  by Earthen  Uranium Mill
    Tailings Covers. (Draft) 1987.

4.  Nichols,  F.  D.,  J.  M. Brink, and  P. C. Nyberg.
    Cleanup  of Radiation Mill Tailings from Properties
    in Monticello, Utah. Presented at  the  Hazardous
    Materials Control  Research Institute  Superfund
    Conference, November 1984.

5.  Shafer, R. A., A. Renta-Babb, J. T.  Bandy, E.  D.
    Smith, and  P.  Malone. Landfill Gas  Control  at
    Military Installations.  Technical Report  N-173,
    U.S.  Army  Corps  of  Engineers,   Construction
    Engineering Research Laboratory, 1984.
6.   Malot, J.J., and  P.R. Wood.  Low-Cost,  Site-
    Specific  Total Approach to  Decontamination.
    Presented at the Environmental and Public Health
    Effects  of  Soils  Contaminated with  Petroleum
    Products  Conference.   University  of
    Massachussetts, Amherst, 1985.

7.   A. D. Little,  Inc. Advanced Techniques for Radon
    Gas Removal. Bureau of Mines Publication PB-
    243898. 1975.

8.   Benneds M. B. Vacuum VOCs from Soil. Pollution
    Engineering, 1987.

9.   Crow,  W. L.,  E.  P.  Anderson, and  E.  Minugh.
    Subsurface Venting of Hydrocarbon Vapors from
    An Underground  Aquifer. API  Publication  4410,
    pp. 3-10, Washington DC, 1984.

10.  Roy F. Weston, Inc.  Task II, In  Situ Air Stripping
    of  Soils Pilot Study.  U.S  Army  Toxic  and
    Hazardous  Materials Agency,  Final  Report,
    October 1985.
                                                25

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                                              Chapter 5
                                       Chemical Extraction
5.1  Purpose
There are several separation techniques that have the
potential to clean radiologically contaminated soils and
tailings. The objective of these technologies would be
to concentrate  the radioactive contaminants, thereby
reducing the volume of soil for disposal. Chemical
extraction is one type of separation technology, which
uses  chemicals to extract the radionuclides from soils
and tailings. Other separation technologies  that might
be used to clean soils  and tailings are discussed in
Chapters 6 and 7 of this report.

The chemical extraction technology generates several
soil fractions.  One  or  more  fractions contain  the
concentrated  radioactive  contaminants;   the other
"cleaner" soil  fractions  may  contain  unextractable
traces of radioactive contaminants.

The   concentrated  radionuclide-contammated  soil
fractions would  require off-site  disposal.  The intent
could be to return the "cleaner" soil fractions, which
would be a major portion of the soil by volume, to  the
point  of origin (the original excavation). Standards for
returning the cleaner  soil  fractions  to  the point of
origin do not currently exist.

It should be emphasized that none  of  the  chemical
extraction techniques  have  been demonstrated at  full
scale  to remove radionuclides from waste masses.
Many of  these  techniques  are  used  in  ore
beneficiation  processes  to  remove   a  single
constituent.  The waste soils  often  contain  radium,
thorium  and uranium, which must all be removed. The
real  practicability of  these techniques to remove
radionuclides  in a field  application  remains to  be
demonstrated.  The  various  potential   chemical
extraction techniques are discussed in this section.

5.2  State of the  Art

Concern about environmental and  health  problems
related  to uranium  mill tailings  has  resulted in  an
extensive study  of  methods  for extracting
radionuclides  from soils and  uranium  mill tailings.
These studies were initiated in order to examine the
migration characteristics of  radium in contaminated
soils  and uranium   mill tailings,  and  to  examine
 chemical extraction as a potential method  for tailings
 remediation  [1-4].

 References at the end of this section contain reviews
 of those techniques  with  the  potential  for  cleaning
 radiologically contaminated soils and  mill  tailings.
 These include extraction with:

        water
        inorganic salts
        mineral acids
        complexing reagents

 There are  notable differences  in  the  extractabihty
 rates  of   these  methods.  These  extractabihty
 differentials are  caused by the  types of soils, ores,
 and  tailings  studied  as  well  as varying  conditions
 within  and  between the methods.  There  also have
 been occasional inconsistencies in  results obtained
 under  similar experimental conditions.  In spite of
 these  differences  and inconsistencies,   significant
 trends in each  method are evident and are reported
 here.

 Though the  chemical extraction technologies have
 been extensively used in  extraction  of uranium from
 mineral ores, their use in cleaning contaminated soils
 and  tailings to acceptable  limits has  been limited to
 laboratory and pilot plant testing. Table 10  shows the
 state of the art of the chemical  extraction  tech-
 nologies.  The  applicability of  these  technologies
 would  be controlled by site-specific factors, and their
 capability must be determined on a site by  site basis.
 Research  and  development  activities  would   be
 necessary  prior  to full scale  mobilization of these
 technologies for site cleanup.

 5.3  Technologies of Potential Interest

 This section  discusses  the four  chemical  extraction
techniques  listed previously.  These technologies
produce an  extractant containing  a radionuclide,
which must be treated to concentrate and collect it for
disposal. This section also discusses the following
chemical methods  for separation and  collection of
extracted radionuclides from the extractant:

        Precipitation and coprecipitation
                                                  27

-------
       Solvent extraction
       Ion exchange

Membrane filtration, which is a physical method used
to separate and  collect the radionuclide  from the
extractant, is briefly  discussed  in  Chapter 6 of this
report.

5.3.1     Extraction of Radionuclides from Soil or
         Tailings with Water

5.3.1.1   Description and Development Status
This  process  would  use water  to  extract the
radionuclide  contaminants. Contaminated  soil  or
tailings would be mixed with large quantities of water.
The  water,  with  the  soluble radionuclide, could be
separated from solids by a combination  of physical
separation methods described in Chapter 6.

The  radionuclide  would then be  extracted from the
liquid by coprecipitation, solvent  extraction, or by ion
exchange (discussed later in this chapter).

Water  solubility  studies  have  been   performed
primarily to examine the teachability of  radionuclides
from  soils  and  mill  tailings  [5-9]. Extraction  of
uranium  from water  is also being  studied  [10-13],
even for uranium concentration less than 3 ppb.

The  water solubility  of  radium salts varies. Chloride,
bromide,  nitrate,  and hydroxide  are water  soluble,
while fluoride,  carbonate,  phosphate,  biphosphate,
and oxalate are only slightly soluble.

The  sulfate is essentially insoluble in water and dilute
acids but is  soluble  in concentrated  sulfunc  acid
(H2S04). Radium sulfate is the least water soluble of
the  alkaline  earth  sulfates  and  probably the least
water  soluble radium compound  known.  Barium
sulfate  is only  slightly more  soluble  than   radium
sulfate.   The water soluble  salts of thorium  include
nitrate,   sulfate,  chloride,  and  perchlorate.  Most
prominent  of the   insoluble  thorium   salts are
hydroxide, oxide,  fluoride,  oxalate,  phosphate,
peroxide, and hydride. Uranium salts that are soluble
in water  include  bromide, chloride, carbide,  sulfate,

 Table 10.  State of the Art of Chemical Extraction Technologies
and hexafluoride. The key insoluble uranium salts are
oxide, tetrafluoride, and tribromide.

The  extraction  of radium from soil is dependent  on
the liquid to solid ratio and optimum time for leaching.
Reference  materials  in this area [5-7] indicate that a
15-minute  leaching  time  removes  the  optimum
amount of  radium; the incremental amount extracted
declines after that time to almost no extraction after 2
hours.

Generally,  the  extraction of  radium  with deionized
water  removes  less than  10 percent  of  the  cation
from the samples studied. As little as 0.1 percent  [8]
has been extracted,  but  as  much as  40 percent has
been removed  [6] under exceptionally high  liquid  to
solid  ratios  (10,000:1).  In  one  study  [9]  water
removed 75 percent of the RaSC>4 from very  fine (-
150  mesh) slime solids.  The removal of thorium with
water  was reported  to be  3 percent in a study  of
uranium mill tailings (4.5 percent radium  and  22
percent uranium were removed),  but the  water was
probably acidic as a result of H2SO4  in the mill pond
from the uranium leaching process  [12]. Soil samples
from the sites of former  radium extraction  companies
in Denver, Colorado  and East Orange, New Jersey
that  were  extracted with water released only 0.1  to
2.3 percent of  the radium  present  and less than  1.5
percent uranium [8].

A detailed  investigation of corresponding experiments
carried out in  Japan,  West  Germany, and the U.S.
has led to  the development  of specific plant concepts
for extracting uranium from sea water  [10,11,13].

The typical cost of extracting uranium from sea water
is  around $300/lb.  However,  enormous  cost
differentials,  ranging  from  $11  to $1,400/lb,  have
been reported [13].

5.3.1.2  Potential Applicable Situations
This method of extraction has not been demonstrated
in the field for cleaning soil  or mill tailings. Laboratory
testing is  needed to identify an  applicable situation.
Since many of the soil cleaning techniques use water
as part of  their  process,  this method  can be used as




Chemical
-
-
_
With
With
With

Technology
Extraction
water
inorganic salts
mineral acid

Laboratory
Testing

X
X
X

Bench
Scale
Testing

X
X
X

Pilot
Plant
Testing



X
Field
Demonstration
with
Radioactive
Material



X

Radiologically
Contaminated
Site
Remediation Remarks



Used in extraction of radium, thorium and
     With complexing agents
                                                                        uranium from ores
                                                                        Used in extraction of uranium from ores
                                                   28

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pretreatment.  Presence of  sulfate in the  soil will
decrease the amount of radium that can be extracted.

5.3.1.3  Advantages and Disadvantages
Advantages - The  main advantages  of using water
are that it  is very inexpensive, completely nontoxic,
uses  ambient  temperatures, and utilizes  simple
extraction  vessels.  The technique can  be  used to
dissolve some radionuclide salts. It can be used as a
pretreatment technique to  reduce  interference at
subsequent extractions.

Disadvantages  - This  method  requires  a large
quantity of  water. The process is relatively ineffective
for removing radioactivity from  soils;  less than 10%
removal for radium and virtually none for thorium has
been demonstrated.


5.3.1.4  Information  Needs
Extraction  with  water  requires  the  following
information:

       Physical,  chemical,  and  mineralogical
       characteristics of the soil.
       Radionuclide concentration for each  particle
       size fraction.
       Amount of water available.
       Water analysis for total suspended solids, pH,
       hardness, background radiation, etc.


5.3.2    Extract/on of Radionuclide from Soil and
        Tailing with Inorganic Salts

5.3.2.1  Description and Development Status
Radionuclide  contaminants  can  be  extracted  by
thoroughly  mixing soil and  mill tailings in a solution
containing  inorganic  salt.  The  slurry  is  filtered,
separating  the   extractant from  the   solid. The
radionuclide  contaminant  is  separated  from  the
extractant  by  ion  exchange, coprecipitation,  or
membrane  filtration [4]. No field demonstration of soil
cleaning using this process  has yet been attempted;
all the research work  so  far  consists of laboratory
experiments.

A  review of the  literature indicates a broad range of
results with the use of salt solutions to  remove radium
and thorium  from mill  tailings  and  soils.  In  many
cases the effectiveness of a given  salt appears to be
related to  several obvious  variables, such  as  the
nature  of  the  tailings  or  soil  (geochemistry,
radionuclide  concentration,  method  of  extraction,
particle size distribution, and chemical composition),
the concentration of the salt solution, temperature,
pH, solid to  liquid ratio, time,  and temperature  [3-
7,9,12,14-16].

An increasing ratio of salt solution to solid, as with
water, plays a positive role in the effectiveness of the
salt  solution  in  removing  radionuclides  from  ore
tailings and  soils [3,5,9].  Multistage  extraction
increases the effectiveness of  the  radium extraction
essentially by increasing the  ratio of solution to solid
[4,5,15].  One  study  [12]  reported as little  as 0.4
percent of radium removed from radium mill  tailings
with 0.1  M  sodium chloride (NaCI).  On  the other
hand, another study [4] reported 94 percent removal
with a 3  M NaCI  solution  at room temperature in  a
three-stage process using 20  liters of solution per
kilogram of tailings, and 90 percent  with 1  M NaCI. In
another study 50 percent of the radium was removed
in a single-stage extraction with a 3 M NaCI solution
[5].  Using 3 M  potassium chloride  (KCI),  91 percent
of the  radium-226  was  removed  in a  two-stage
leaching process at room temperature [16].

The extraction  of thorium  by  salt  solutions has
received less  attention than the extraction  of radium.
One study [12] reported that, while  13 percent of the
radium was removed from uranium mill tailings  with  a
0.1 M NaCI solution, only 0.02 percent of the thorium
was removed. In another experiment, no thorium was
removed by a 3 M NaCI solution, while 62  percent of
the  radium was  extracted.  However, a  study  of
various  inorganic phosphates [17] indicates that 60-
80  percent of  both  radium  and  thorium can be
removed  by  sodium hexametaphosphate ((NaPOaJe)
from a  fine particle fraction (-200 mesh) of uranium
tailings  that were produced by  leaching with H2SO4.
The study also  indicated that salt interferes with the
removal of uranium during  the H2S04   extraction
process.  Other phosphate  salts  (orthophosphate,
pyrophosphate, tnpolyphosphate) were not effective in
extracting  thorium from the tailings.

The ability of the salt to extract radium or  thorium is
primarily reflected in the solubility of the compound or
complex that it forms with  radium and thorium. The
presence  of sulfate in soil greatly affects the ability of
the inorganic salts to extract radium, since the  radium
sulfate  that is formed  is  the  least soluble  radium
compound encountered in  mill  tailings. Hydroxide is
the  analagous  anion  in  thorium  chemistry  since
thorium hydroxide is  the  least  soluble thorium
compound encountered. It is reported in one study of
uranium mill tailings  [3]  that  the  radium-leaching
power of several anions decreases  as  follows:  Cr  >
NO3- >  HCO3-  > HO4-  >  PO4-3.  It  was also
found that washing to remove soluble sulfates before
radium leaching helps dissolve the radium.

The  effectiveness of aluminum  salts  in  dissolving
radium and thorium is minimal, probably as a result of
the hydrolysis of the  cation, producing a gelatinous
precipitate that retains  radium by adsorption. This is
particularly important  since  many soils and tailings
contain  aluminum  and  similar  cations. The  barium
cation  also was found to  be  less  effective  than
sodium in  solubilizmg radium,  supporting the
hypothesis that  an insoluble barium radium  sulfate
                                                  29

-------
(Ba(Ra)SO4) salt is a major form of  radium  in most
mill tailings. [5]

The barium cation would be expected to be effective
in  releasing radium bound  by adsorption on particles
containing metal hydroxides,  silicas,  and  clays  but
ineffective in solubilizing the Ba(Ra)SC>4.

The  effectiveness of  cations  of  various salts  in
releasing radium decreases in the following order [3]:
Cs+>  Ca + 2>  Mn + 2> NH4+ > K+  > Na+  > Li + .

5.3.2.2   Potential  Applicable Situations
Inorganic  salt  extraction  has not undergone field
demonstration for cleaning  radiologically contaminated
sites.  Laboratory or pilot plant testing will be needed
to  identify applicable situations.  The  presence  of
sulfates in the soil  will greatly affect radium removal,
as sulfates will  form  radium sulfate, the least soluble
radium compound.  The presence of hydroxide in soils
and tailing will  similarly  affect thorium  removal.  The
use of  salts interferes with  the removal of uranium by
sulfunc  acid.  This process should not  be used as
pretreatment to  an acid extraction process.

5.3.2.3   Advantages and Disadvantages
Advantages  -  A  high  percentage   of  radium  and
thorium may be removed.  Processes  may  operate at
ambient temperatures. Most  salts  are  relatively
innocuous. Simple extraction vessels  are  required.
Recycling of salts may be possible.

 Disadvantages -  Large amounts  of salts may be
required with  large  solution-to-solid ratios. Some
salts,  such  as chloride,  may   be  environmentally
undesirable.

5.3.2.4   Information Needs
For  extraction by  salt  solution,  the  following
information is required.

        Physical,  chemical,  and  mmeralogical
        characteristics of the soil.
        Amount of water available.
        Water analysis for total suspended solids,  pH,
        hardness.
        Background radiation,  etc.

5.3.3     Extraction of Radionuclide from Soil and
         Tailings with Mineral Acids

5.3.3.1   Description and Development Status
Historically, radium has been  extracted  from carnotite
ores with mineral  acids -  H2S04, hydrochloric acid
(HCI),  or nitric  acid (HNOa) [18,19].  Under favorable
conditions, up  to  97  percent  of the  radium  was
removed. Thorium  ores are extracted industrially with
   (among other reagents) fuming H2SO4 or HNO3 [20].
   Uranium is also extracted  from mineral  ores by  acid
   leaching [21].

   Sulfuric acid,  rather than hydrochloric or nitric acid, is
   commonly utilized  for leaching in uranium extraction
   due to its less corrosive nature and lower costs.

   In  all  these processes  the  ores are ground  to 28
   mesh  and  mixed  with water to form  a slurry.  The
   slurry  is pumped  into a leach circuit,  maintaining a
   pulp consistency of 50 percent solids. The solids are
   separated  from the leach liquid by physical methods.
   The radionuclides are removed from the  leach
   solution by  ion exchange,  solvent  extraction,  or
   precipitation [21].

   It appears  from  a survey of recent reports on  the
   extraction  of  radium  and  thorium  that these metals
   are readily extracted  by  several  mineral acids  from
   soils and  soil components [3,5,7,22], ores,  and  ore
   tailings [8,9,14,15,23-28].  Although fuming H2S04 is
   used  in  industrial  processes  for the  removal  of
   thorium  from  ores  as  soluble thorium  sulfate
   Th(SC>4)2) [20], one  would not expect the acid to be
   useful for  the extraction of  radium,  considering  the
   insolubility of radium sulfate  (RaS04). However,
   RaSO4 is  somewhat soluble  in concentrated H2S04
   [29], and  several  studies have indicated that the hot
   acid will  remove  between  70-80 percent of  the
   radium  and  80-90  percent of  the  thorium  from
   uranium mill  tailings  [24,28].  A   recent study  [25]
   demonstrated that between  14-40 percent radium
   can be removed from uranium ores by dilute H2S04
   in a countercurrent process at 72C, in  the presence
   of  oxidizing agents; approximately 86 percent  of the
   thorium was removed.

   Nitric  acid has proved  to be  very efficient  in  the
   extraction  of radium and thorium  [9,26,30]. Generally,
   the best results with  ores  and ore tailings have been
   achieved with approximately  3 M HNOs  solution at
   temperatures between 70  and  80 C  for  about 5
   hours  in   two-  or  three-stage  processes   with
   hquid-to-solid ratios of 2:1 to 4:1.  For example,  97
   percent radium and 99 percent thorium were  removed
   from uranium ore or ore tailings (H2SO4 or carbonate
   leached)  with 3 M  HNOa at 70C in a two-stage
   process, with a reaction time of 5 hours [26]. Over 99
   percent of the uranium  was  also  removed  from the
   ores.  The resulting Ra-226  level was  as low  as  17
   pCi/g, and the  thorium  level was 7 pCi/g  [26]; the
   tailings  before  nitric  acid  extraction  contained  716
   pCi/g  Ra-226 and  88 pCi/g Th-230, respectively.

   Similar results were achieved using HNO3 with ores,
   slimes, solids, and sand tailings [9], with 89 percent
   removal of  radium in a  one-stage  process with 6
   percent  solid  loading.   A  six-stage,  batch
   crosscurrent  process  [31] removed 98  percent of the
   radium from ores and  tailings  with a final Ra-226
30

-------
level of 10  pCi/g. Remarkably similar results have
been  obtained  with  HCI  solutions [9,8,23,25].  Like
HNOa extractions, the best results occur with 1.5 to 3
M HCI at about 70-  85C with  multiple extractions.
Ninety-three percent  of radium (<  28 pCi/g) and  86
percent of thorium removal was  achieved  in a four-
stage,  countercurrent process in  the  presence  of
other oxidants [25].

More  than  95 percent of the  radium was removed
with 3  M HCI at 85C in  one hour with a  liquid-solid
ratio of 4:1  [9]  and 92  percent radium-226  was
removed with  1.5 M  HCI at 60C in a three-stage
leaching process with a 4:1 solid to liquid  ratio [23].
Depending  on the size of the  soil particles  and  the
nature  of  the soil, 27%  to  100%  of  Ra-226
extraction  has been  demonstrated in  the  laboratory
from soil contaminated with radium mill tailings using
0.1 M HCI.

Combining dilute  acids  with  inorganic   salts  has
produced  leaching  solutions  that achieve results
similar  to  those  of  the  more-concentrated acid
solutions [9,14,15,27]. Mixed NaCI  and HCI solutions
were used to extract radium  from mill  tailings [9,14].
In a  three-stage  process  (30  minute  stage)   94
percent of radium was removed  with 0.3 M  NaCI in
0.1 M HCI at 25C [14].  Calcium chloride  (CaC^) in
HCI has produced very good  results  even at room
temperature. Removal of  96  percent of the uranium,
97 percent of  the  radium,  and  75  percent  of  the
thorium with 0.045 M CaCl2 in  0.125 M HCI at  room
temperature in  a two-stage leaching process  has
been reported  [27].  A 91  percent removal  of Ra-226
and 79 percent removal  of Th-230  were obtained
from tailings with  1  M CaCl2 in 0.1 M HCI at 21  C
and  a  2:1  liquid-to-solid  ratio  with  30 minutes
contact time.

An acidic environment would be  expected  to have a
positive influence  on the  release of cations such  as
radium and thorium  from  soils  and tailings that have
the potential  to bind  metal  ions. This is  especially
important  in  determining  the  extracting  power  of
various acid solutions on ores and tailings, since most
of these materials contain soil  particles with a large
amount of amorphous silica  (up  to 90 percent) and
hydrated metal  oxides such as  aluminum  and  iron
oxides.

Adsorption on  surfaces   of  amorphous  silica  or
hydrated metal  oxides is strongly affected  by the
acidity  of the environment [2,3].  The  surface charge
of silica is positive at  pH  < 1,  is  zero  between pH 1
and 3,  and becomes progressively  more  negative
above pH 3 [2].

Hydrated metal  oxides that have aged  will not readily
dissolve in acid solutions, but an increase  in  acid
concentration will diminish the  number of oxide sites
available  for  binding [3], thus enhancing  the
dissolution  of radium and  thorium.  Natural  organic
acids, such as humic and fulvic  acids found in soils,
tend  to decrease  their  binding  capacity  thus
increasing the  dissolution  of  radium  and  thorium.
Increased concentrations of HNOa and  HCI also  will
promote  the dissolution  of  Ba(Ra)S04.  With
increased concentration, the salt dissolves in  water
with  the  formation of barium hydroxide  (Ba(OH)2), a
slightly  soluble  base, and  the more  soluble radium
hydroxide (Ra(OH)2), which are converted  by  the
acids to  more soluble salts, barium chloride  (BaCl2)
or barium nitrate  (Ba(N03)2) and  radium  chloride
(RaCl2)  or radium nitrate (Ra(N03)2) [25].


5.3.3.2   Potential Applicable Situations
Mineral  acid extraction  techniques  are  being
developed and  have been  used to extract  radium,
thorium, and uranium from mineral ores.  Improvement
to these acid  extraction processes has   been
demonstrated in the laboratory. These  demonstrations
show that the acid extraction processes can  remove
most  of the   metals,   both   radioactive and
nonradioactive,  and therefore may be applicable  for
cleaning radiologically contaminated sites.


5.3.3.3   Advantages and Disadvantages
Advantages - An advantage of extraction with acids is
that a high percentage of radium  and thorium removal
is possible. Uranium  and other metals would also be
removed.  These  processes require relatively  small
liquid-to-solid  ratios   compared  to  extraction with
water or inorganic salts, thus requiring less pumping
power  and smaller  holding and reaction  vessels.
Costs can be reduced if  the acids are recycled.

Disadvantages  -  The  main  disadvantage  of this
process would likely  be  the increased operating and
capital costs  due  to expensive  reagents,  higher
operating temperatures,  and the  stainless  steel
reaction  vessels and pipes  needed because  of  the
corrosiveness of  acid.  A  multistage  process  is
needed,  which   adds  to the costs.   A  major
disadvantage  of these techniques is that the anions,
such as N03~   or CI",  are  environmentally
undesirable. The resulting chemically leached material
may  create a waste stream that is more harmful than
the original tailing  mixture.


5.3.3.4   Information Needs
The  analyses and  requirements  listed below are
required in implementing treatment procedures.

       Physical,  chemical, and  mineralogical
       characteristics of the soil.
       Radionuclide  concentration  in each particle
       size fraction.
       Amount of water  available.
                                                 31

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5.3.4
Water analysis for total suspended solids, pH,
hardness, background radiation, etc.

 Extraction of Radionuclides from Soil
 and Tailings with Completing Agents
5.3.4.1  Description and Development Status
This process differs from  acid  extraction  in  that
complexing  agents  like  EDTA  (ethylenediamine-
tetraacetic acid) are used instead of mineral acids.

Radium forms stable complexes  with  many  organic
ligands (a  molecule or anion that can bind to  a metal
ion  to form a  complex). For  that reason,  several
complexing agents have  been  investigated  as
potential candidates  for extraction of radium  from
uranium mill  tailings [3,9,31-34] and,  in  one case,
from soils  [35]. Thorium is not likely  to be removed
by complexation.

Several successful  radium  extraction  tests   with
complexing agents  have  been reported. Up to 92
percent (to 40 pCi/g) of radium  content was removed
from mill tailings using 0.15 M Na4  EDTA at 60C, pH
10,  and a liquid-to-sohd ratio  of about  7/1  in  a
three-stage process [23]. After collecting the Ra as
Ba(Ra)S04, the  EDTA was recovered for reuse by
lowering the pH. Another study [33] removed 80-85
percent of the Ra with a 0.04 M EDTA solution at pH
10,  23C,  and  a liquid-to-solid ratio  of  2:1.  A  pre-
wash  with  water  (25 l:kg) removed calcium sulfate
(CaS04), which tends to interfere with the extraction.
Using  6.65% sodium diethylenetnammepentaacetic
acid  complex  (Na$ DTPA),  another  study   [34]
reported removing up to  85  percent  of  the  radium.
The crosscurrent  or  countercurrent process  used  m
this study  obtained maximum yields after 2 hours  at
20-25C  with  a  liquid-to-sohd ratio of about 9:1.

A   recent  study [32]  described   a   reducing-
complexing treatment for the  leaching  of  radium from
uranium  mill tailings.  A reducing  agent,  sodium
hydrosulfite (N32S204), is added in order  to reduce
Fe + 3  and  similar  cations. Using 0.04 M Na2 EDTA,
0.04  M N32S204  and  1  M KCI  (to  mask  the
adsorption sites on silica) for 1  hour at pH 10 with a
hquid-to-solid  ratio  of  10:1,  87 percent  of  the
radium was removed, leaving  44 pCi/g  in the residue.

Adopting a procedure of keeping the  hquid-to-solid
ratio initially high and slowly adding the tailings to the
leach  solution  had  a  major effect  on  radium
extraction,  reducing the residue from  44 to 31  pCi/g
radium. A  comparison with several other complexing
agents using 0.1 M solutions of the agents under the
same  conditions  was  made:  Citrate  removed 67
percent to 120 pCi/g, and nitnlotriacetic acid (NTA)
removed 85  percent to  48  pCi/g. Note that these
solutions are 2.5  times more concentrated than the
Na2 EDTA solution (0.04 M).  This study also reported
the recovery of 92  percent of the Na2 EDTA  by
bringing the leach solution to pH 1.8.

Most  of the  studies  of  radium  extraction  with
complexing agents have been with  EDTA.  Radium
extraction during leaching is  improved by  keeping the
radium concentration low in the solution, particularly
in  order to  shift the equilibrium  representing  the
dissolution of Ba(Ra)SO4 [3].

One would expect thorium  extraction to  be  assisted
by  complexing  with EDTA  or another   suitable
complexing agent.  Leaching of radium  with  EDTA  is
generally performed  at pH  8 and  10.  Unfortunately,
above pH 3 thorium forms a very insoluble hydroxide
whose formation competes  with  the formation of the
thorium EDTA complex.  Thus, at a pH where the
formation of an EDTA complex with thorium  would be
favored, the  thorium  cation  is not  available for
complexation.

Other cations  found in  soils  and tailings,   such  as
Fe"1"3 and Ti + 4,  behave  in a similar fashion  and
compete with  Ra + 2  dissolution by forming  insoluble
hydroxides that adsorb the  cation. Studies  [3]  have
determined  that  the result  of  these  competing
equilibria will  prevent the dissolution of  radium with
EDTA.  But  with  the appropriate  reducing agent,
Fe + 3,  Ti + 4, and  similar cations will be  reduced  to
lower oxidation states that tend to form more soluble
hydroxides.

 The  radium  EDTA complex  formation will  then
compete favorably with hydroxide formation, causing
the hydroxides to be solubilized,  releasing  radium
adsorbed on  these materials [2,3]. Thorium cations
are  not  reduced  to  lower  oxidation   states,
subsequently  forming  more  soluble  hydroxides.
Therefore, radium  extraction would  be  assisted  by
prior extraction of thorium.


5.3.4.2  Potential Applicable Situations
This  method  of  extraction  has  not  been  field
demonstrated for radiologically contaminated soils and
tailings. Laboratory experiments  show  that  radium
forms  stable  complexes  with  EDTA,  suggesting  its
potential for  application in cleaning radium from soils
and tailings with low  concentrations of  thorium.  Soils
and tailings with high concentrations of thorium may
require  prior extraction of thorium before using this
technique to extract radium.


5.3.4.3  Advantages and Disadvantages
Advantages - One of  the  mam  advantages  of
extraction  of  radionuclides  with  a  complexing agent
would  be  the expected high  percentage of radium
removal. Low  reagent  concentrations  are  required,
and  the reagent can be  recycled, thus  reducing
operating  costs.  The   process works  at  ambient
                                                 32

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temperatures,  and  many  of  the  reagents  are
innocuous.  Therefore,  expensive materials such as
stainless steel for  vessels and piping would  not be
needed.

Disadvantages -  Complexing  reagents are  very
expensive.  This process  would not remove thorium,
therefore, other processes  might be  required to
remove thorium  prior to  the removal of  radium by
complexing  agents.  A multiple-stage  process is
probably required, adding to the capital and operating
cost.


5.3.4.4   Information Needs
The following information  is  required  prior to
extraction with complexing agents.

        Physical,  chemical, and  mineralogical
        characteristics of the soil.
        Radionuclide  concentration in each  particle
        size fraction.
        Amount of water available.
        Water analysis for total suspended solids, pH,
        hardness,  total dissolved solids,  background
        radiation, etc.
5.3.5    Technologies for Separating
         Radionuclides from Extractant
The previous  section  discussed  the leaching  and
extraction technologies that produce a pregnant liquor
containing the radionuclides.

Radium  and  thorium  extracted from soils and  mill
tailings will be in solution  with many other molecular
and  ionic compounds.  Some of  the ions may  be
simple, while others will be complex,  depending upon
the nature of  the  sample to  be  extracted and  the
leaching  solution(s). Other molecular substances  and
material  will probably  be present as  colloids.  Still
other fractions will be  in suspension and will separate
upon settling or filtering.

The support  technologies utilized  in  treating  the
extractant to  remove  the radionuclides for disposal
are:

       precipitation and coprecipitation
       solvent extraction
       ion exchange
       membrane filtration

The first three technologies  are  chemical methods
and  are  discussed  in  this chapter. The last,
membrane filtration, is a physical  separation method
and is discussed in Chapter 6.
5.3.5.1   Description and Development Status
Precipitation  and  Coprecipitation  - By addition  of
chemicals  the  radionuclides can be  precipitated.
Several stages of precipitation at controlled pH  are
used. The  pH is  readjusted in the precipitation tank
near the end of  the  circuit. The slurry  from  the
precipitation tank  is  dewatered  in  thickeners and
followed by filtration (see Chapter 6 for  description of
dewatering  technologies). The filter cake,  containing
the concentrated radionuclide,  is  then  ready  for
disposal. Precipitation, however,  produces products
with  impurities.   This  may not  be  a  problem  on
cleaning  soils and tailings. However,  in extraction of
uranium from ore, solvent extraction or  ion exchange
is used before precipitation to obtain a purer product.

Radium forms a  very insoluble salt with sulfunc acid.
Sulfunc acid is commonly used to form a  precipitate
of RaSC>4,  but sodium sulfate (Na2SC>4) is also used
[29].  Thorium may  be  precipitated  as  a  highly
insoluble,  gelatinous  hydroxide  with  alkali   or
ammonium hydroxide  [1].  Thorium is also precipitated
by sodium oxalate/oxalic acid solutions at a pH  of 1.2
from acid solutions [36].  The concentration of radium
and thorium cations  in the extractant from soil and
mill  tailings  may be low enough  that a   direct
precipitation process would not be appropriate  to  the
collection of these radionuclides. Radium and thorium
may  be  coprecipitated by the addition of a  simple
precipitating agent such as H2S04.

Small  quantities of  radium  cations   can  be
coprecipitated from  solution with  many  different
carrier compounds [29,37].

The  use of the  classical radium carrier,  BaS04,  to
precipitate  radium from  leach solutions   has  been
reported  by several  investigators  [4,23,31,32,38,39].
A review [36]  of  other natural organic carriers  (such
as tannin and gelatin) reported  that these  carriers
removed  90  to   100 percent   of  the  radium  in
coprecipitation processes. In a study [4] it  was  found
that  BaS04  is slightly  soluble  in  a  HNOa  'each
solution (0.07 g/l  in 3 M  HMOs); however,  95 to 100
percent of  radium may be coprecipitated from nitric
acid  leach  solutions  using very  dilute (<10 mM)
BaCl2 solutions in the presence of sulfate ions [4,31].
The  use of a  silica-bed  filter to  remove Ba(Ra)SO4
has also been suggested for the  removal  of radium
from uranium mill  tailings  [32].

Thorium coprecipitates with a wide variety of insoluble
hydroxides  such as iron, zirconium, and  lanthanum as
well  as zirconium iodate  or  phosphate  from acid
solutions [20]. Calcium fluoride  and calcium oxalate
are also used as  coprecipitants [38]. One study [40]
reported  that  60  to  100 percent  of  the thorium
coprecipitates   with  BaS04   solution;   lower
concentrations of thorium (<0.09 mM)  removed  the
largest amount of the cation. Another study [39] used
                                                  33

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an oxalate  to remove thorium from a 3.6 M HNC>3
leach solution. The oxalate is very insoluble in HNOa;
no radium was carried by the coprecipitate. Using 20
percent NaOH, more than 96 percent of the thorium
was coprecipitated in the presence of  Fe at  a pH of
4.2 as ferric hydroxide (Fe(OH)3) [38].

Uranium  is precipitated  from  solution  by addition of
sodium hydroxide, gaseous  ammonia,  hydrogen
peroxide, or magnesia.  Precipitation  using  sodium
hydroxide,  sulfunc acid, and gaseous  ammonia
produces purer uranium with little sodium.

For a plant  processing 10,000 tons of uranium ore per
month,  the typical capital  and  operating  cost of
precipitation circuits  are estimated  to  be 8750,000
and $0.50  per  ton of ore processed,  respectively.
[41,42,47].  These costs  are  in 1985  dollars. These
costs  are for uranium ore processing and  are not
intended to be applicable to any particular site.

Solvent Extraction - Solvent  extraction is an  efficient
method for  separating uranium on  a commercial scale
[42].  There are  no commercial  solvent  extraction
processes to extract radium  or thorium. The solvent
extraction,  as applied to  uranium extraction plants,
consists  of a  two-step  process. In  the first step,
termed  "extraction,"  the  dissolved  uranium is
transferred  from the feed solution  (or aqueous phase)
into the organic or solvent phase. The second  step,
called  "stripping,"  recovers  the  purified   and
concentrated uranium product into a second  aqueous
phase  after which the barren organic is recycled  back
to the  extraction  step.  The  aqueous and  organic
solutions flow continuously and  countercurrently  to
each other  through the required number of contacting
stages in the extraction  and stripping portions of the
circuit.  The uranium  is  recovered from the  second
aqueous solution by precipitation.

The extraction of metal from the aqueous solution and
its eventual transfer to another aqueous solution (the
strip liquid) involves  the use  of  various  reagents
(extractants, diluents, and modifiers) and  requires a
suitable  vessel   to  bring about intimate  contacts
between the different liquids.  The extractants are the
reagents in the  solvent that  extract  the metal  ions.
Extractants that are used in recovery of uranium from
acid leach  solutions are  alkylphosphoric acid, amines,
tri-n-butyl phosphate  (TBP)   and  trioctyl phosphine
oxide (TOPO).

The diluents  comprise  the  bulk  of solvent  and are
inert ingredients whose  principal function is to act as
carrier for  the relatively small amount of extractant.
Kerosene  is the most  commonly  used  diluent,
although other organics  such as fuel oil, toluene, and
paraffins are also used.  The most commonly  used
modifiers for increasing  the solubility of the extracted
species are long chain  alcohols such as isodecanol
[41,42].

Radium compounds have very  low  solubilities  in
organic solvents [43]. In most  extraction  procedures
for  separating  radium  from  other  elements, those
other elements are  usually extracted into  the organic
phase [29].  For example,  the  use  of 2-thenoyl-
trifluoroacetone (TTA) or tnbutylphosphate (TBP) has
been successful in  the separation  of radium from
other elements.  However, a mixture of TTA  and TBP
in  carbon  tetrachlonde   (CCU)  has  been  used  to
extract radium for quantitative analysis  [29]. Radium
tetraphenylborate has been removed by nitrobenzene
from  an  alkaline  solution,  and  solutions of  8-
hydroquinoiine (HOQ) and some of its derivatives will
also  remove  radium  from  an  alkaline  solution
[43,44,45].  This extraction  characteristic  may   be
significant in the separation of radium from thorium in
leach solutions. There  is no reported  use  of these
solvent systems for the  removal of radium from soils,
ores, or mill tailings.

Organic  solvents  are   used  extensively   for  the
extraction of thorium from  ore and  mill tailings leach
solutions [31,36,38,39]  and for the extraction of  the
cations in analytical  procedures  [20,43,29]. Generally,
these procedures take advantage of  the  solubility of
inorganic complexes  such  as  thorium chlorides,
thorium  nitrates,  or thorium  sulfates  in   organic
solvents. Thorium sulfates are formed during leaching
of the ore  with H2S04  and thorium  nitrates,  and
thorium chlorides are produced by the  HN03 or HCI
dissolution,  respectively,  of precipitated   thorium
hydroxide. The most common organic solvent used in
these extractions is TBP.  For  example, a 30 percent
TBP  in  kerosene  was  used  in  the  extraction  of
thorium from the H2S04 [38] liquor. In another study
[39]  30  percent TBP  in normal-hexane was  used.
Still  another study  [31]  used 30  percent TBP in
normal-  dodecane  for  HNO3  solutions  of thorium
from  leach  solutions. A review of the extraction of
thorium  [36] listed  over  two dozen  organic solvent
systems involving TBP,  other organophosphates,  and
various amines, which are applied to remove thorium
and  actinides from leaching  acids  such  as H2SO4,
HCI, and HBr.

Primary  amines  and   straight-chain  secondary
amines have also been  used  to extract thorium in the
processes for  the  recovery  of uranium and thorium
from ores.  After  the  extraction  of  uranium  with
triisooctylamine, thorium is removed with 5 percent
sec-dodecyl  or 5 percent  di(tridecyl)amine  in
kerosene.

For  processing of  uranium ore at a  rate of 10,000
tons of ore  per  month, the  typical  capital  and
operating costs for a solvent extraction  circuit  were
estimated as one million dollars and  $1.00/ton of  ore
processed,  respectively [42,47].  These costs are in
                                                  34

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1985 dollars. These costs are based on uranium ore
processing and are not intended to be  applicable  to
any particular site.

Ion Exchange -  Leaching  used  in  extraction  of
uranium and other  minerals is a nonselective process
resulting  in the dissolution of elements in  addition  to
the desired constituents. Ion exchange is one process
used for  concentrating the desired constituents from
the leached  solutions.  The  resin ion  exchange
technique involves the interchange of  ions  between
the aqueous solution and a solid resin. This  provides
for a  highly  selective and  quantitative method  for
recovery  of uranium  and radium.  The process  of
removing  dissolved ions  from solution by  an ion
exchange resin is  usually termed  adsorption  in the
uranium industry [4,21,42,46,47].

There are  several  resins  available for  extraction  of
both  radium and uranium. For uranium  extraction by
ion exchangers, strong and intermediate base anionic
resins  are loaded from either  sulfuric  acid  or  a
carbonate leach feed solution. The loaded  resin  is
stripped with a chloride, nitrate, bicarbonate, or an
ammonium sulfate-sulfuric acid  solution to  remove
the captured uranium.  These resins are semirigid gels
prepared as  spherical  beads.  Radium  can  be
extracted by using synthetic zeolites.

The total amount of uranium that may be adsorbed is
a  function of the  quantity  of anionic complex  in
solution. Two to five pounds of UaOs can be captured
for each  cubic foot  of  resin.  Higher capacity is not
possible  because of  competition for ion sites in the
resin by other anions present.

The other  anions  present  in  the  acid  solution that
compete  with  uranium for resin sites include HSO4",
S04~2, and various impurities that dissolve along with
the uranium during leaching.  The extent  to which one
of these anions adsorbs on the resin is influenced by
its concentration in solution relative to other ions, pH,
and by the relative affinity of the resin for the  anion.

Removal  of the uranium from the  saturated resin  is
termed elution. It is customary to refer to  the eluting
solution as the eluant and to the final  effluent as the
eluate. Chloride elution is  best accomplished in acid
circuits with concentrations of  from  0.5 to  1.5  M CI".
Nitrate elution can also be  used  at a 1  M  NOa"
content.

The  ion  exchange  process  is,  in most plants,  a
semicontinuous series of  operations  integrating the
adsorption and elution steps with  various stages  of
washing,  resin regeneration, etc.

There are three types  of ion  exchange systems: fixed
bed,  moving bed,  and  resin-in-pulp.
For a  fixed  bed ion  exchange  system, cylindrical
pressure  vessels  with  dished  ends are  usually
constructed  of  steel and lined  with  rubber for
corrosion resistance. The resin bed rests upon a bed
of crushed and sized  rock,  which is in  turn supported
either by a flat rubber-covered steel false bottom or
the dished bottom of the column.

For a moving bed ion exchange system, the resin is
transferred  to separate  columns for  adsorption,
backwashing,  and elution.  This  procedure has  been
performed  in six  Canadian  plants,  one  U.S.
processing plant, and two  U.S.  mine  water recovery
plants.  The  major  plant  installations   utilize  ten
columns  per set,  with  two  groups  of  three on
adsorption, one  group of three  on elution,  and  one
special  column  for transfer and backwashing. This
arrangement  eliminates the danger of mixing leached
solution and eluate solution  due  to  improper
operation.

The moving  bed  processing  cycle does not vary
significantly from  that in the fixed bed  plants, except
that either two or three columns are continuously on
adsorption  without  interruption,  and  elution  is
conducted with three columns in series.

For a  basket resin-in-pulp ion  exchange  system,
the resin  is  contained  in cube-shaped  baskets
formed  of  stainless  steel  and  covered with  either
stainless steel or plastic screen cloth.

The baskets  are moved  up and down at a  rate of
between  six  and  twelve  strokes  per  minute  in
rectangular shaped  tanks containing flowing slurry or
eluting solution.  The  basket movement consolidates
the resin bed during an up stroke, thereby squeezing
out residual solution,  and  expands the bed  for free
solution access during the down stroke.  From six to
eight  stages  are employed in adsorption  and  from
seven  to fourteen  in  elution, with  more   stages
required when sulfuric acid  is used for elution.

Some  of  the new  developments in   ion exchange
equipment are:

       Porter and  Stanton contactor.  Resin  passes
       downward and solution flows upward.
       Higgins contactor.  A  single column  divided
       into two sections by rotating valves.
       Jigged bed  ion exchange. Uses jigged  action
       in the resin to cause  more dense  uranium
       loaded resin.  Department of Defense  is
       investigating the  use  of the   equipment  to
       clean a missile site  in New Jersey.
       Winchester Fixed  Bed.  Pulp flow is introduced
       through an oscillating distributor.
                                                  35

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       Bureau of Mines  ion  exchange.  Divides  the
       adsorption  column  into  compartments
       separated by orifice plates.

Based on an ion  exchange system with a capacity of
200 tons per day,  the  typical capital cost estimates
range  between  $300,000 and  $1,000,000.  The
operating cost estimates for  that tonnage capacity
range between $1 and  $3 per ton of soil processed.
[42,47]  These costs are for  processing  of uranium
ore and are not applicable to any particular site.


5.3.5.2  Potential Applicable Situations
Precipitation and Coprecipitation - Precipitation and
coprecipitation  have been used  in  some extraction
schemes to separate uranium from  the  leach liquor.
All currently operated uranium extraction plants, with
the exception of a few using a carbonate leaching
circuit, employ precipitation to recover  the uranium
from the solvent extraction stripping liquor or from the
ion exchange  eluate.   Precipitation  could be  used
directly to extract the radionuclide from the water and
inorganic salt extraction pregnant liquor.

Solvent  Extraction - Solvent  extraction  is  the
preferred technology for extracting uranium from acid
leach liquor circuits.  However,  it has  not  proved
feasible to apply  solvent extraction to carbonate leach
liquors or to slurries containing  appreciable amounts
of solids [42].

Ion Exchange -  The use of ion exchange has been
documented in  a  number of  applications.  These
include:

       Decontamination of uranium  mill processing
       water and water pumped from the mine.  Ion
       exchange also  has been used  to remove
       radium from uranium mill tailings [47].
       The Mining Science  Laboratory  in Canada
       has demonstrated ion  exchange extraction as
       a means of cleaning  the leach  liquor from
       tailings for uranium, thorium, and  radium [48].
       Extraction of uranium  in several  plants in  the
        U. S. [42].
       An  alkaline  leaching  process in which  ion
       exchange is used  to extract the impurities and
       produce  a  high grade liquor  for  precipitation
       and recovery of uranium [21].


5.3.5.3  Advantages and Disadvantages
Advantages - Precipitation and coprecipitation  are
used  extensively in  uranium recovery  operations.
They can  be operated  in both batch and continuous
operation mode,  and involve low capital cost.

Since  solvent extraction technology involves  only
liquid-liquid contacts, it is readily  adaptable to other
systems and can  be  performed as a  continuous
operation. Solvent extraction is also readily adaptable
to efficient  and economical automatic continuous
operation. Other advantages of solvent extraction are
better  selectivity and greater  versatility than  ion
exchange.

Ion exchange  is an excellent and economic  method
for removing very fine radioactive contaminants  from
liquids. In the absence of  ion exchange  equipment,
more  expensive ultrafiltration  or solvent extraction
techniques are used. Ion exchange is less sensitive to
the volume or  grade  of  liquor  than the  solvent
extraction  techniques.  Ion exchange  has  been
extensively used in  cleaning radioactive contaminants
from nuclear power plant water  streams, providing a
valuable   database  for  the  development  of  ion
exchange equipment to clean contaminated soils.

Disadvantages - Precipitation  and  coprecipitation
involve a  difficult, cumbersome,  and costly operation
requiring  complex chemical  separation.  Close control
of operating conditions is required.  The pH must be
monitored and controlled  to  have  better product
recovery.  The  precipitation procedure is not adaptable
to automatic  control,  and most  plants  currently
operate on manual.

The  mam disadvantage of  solvent  extraction is that
the feed  solution must be essentially free of solids. It
has not proved economically feasible to apply solvent
extraction  to  carbonate  leach  liquors.  Emulsion
formation  in  solvent circuits causes trouble. The small
loss of solvent to tailings is not  only costly, but may
be a source of stream pollution.  Solvent reagents are
also  very costly. The solvent extraction  process is
more sensitive to the volume and grade of liquor than
the ion exchange  process.  Molybdenum  is strongly
extracted  by amines  and  builds up in the amine,
acting as poison.

In using  ion exchange, impurities in the liquor can
overload  the ion exchange resins. Trace metals  such
as molybdenum, vanadium, radium,  and sulfate in the
leached liquor can poison the resin, reducing its life.


5.3.5.4   Information  Needs
The  analyses listed  below  must be  considered  in
preparing to  implement  precipitation,  solvent
extraction, and ion exchange procedures.

       Chemical composition  and trace ion analysis
       of the  leach liquor.
       Solid content and pH of the liquor.
       Trace element content

5.4  Typical Costs of Chemical  Extraction
     Technologies
It  is estimated  that  the typical cost  for chemical
extraction would range from $50-150 per  ton of soil,
                                                  36

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assuming that the waste is in a form suitable for the
use  of these  technologies.  Transportation  and
disposal costs  for the  concentrated  and "clean"
fractions are not  included  in  the  above  figure.
Because of lack of process data, the costs of some
of the chemical  extraction technologies  are based on
profitable ore processing techniques and  not on the
costs of removing enough  radioactivity  from  the
contaminated material to render  it "clean." As such,
these costs could be  much higher.  Since more
detailed process information is lacking,  these figures
represent an educated  guess. These  costs are not
intended to be applicable to any particular site.

5.5  References

1. Landa, E. R. Isolation of Uranium Mill Tailings and
   Their  Component  Radionuclides  from  the
   Biosphere -  Some  Earth Science  Perspectives.
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   Virginia, 1980.

2. Shoesmith, D. W. The Behavior of Radium in  Soil
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   Pinawa, Canada, 1984.

3. Nirdosh, I., S. V. Muthuswami, and M.  H. I. Baird.
   Radium  in  Uranium  Mill  Tailings  -  Some
   Observations  on   Retention and  Removal.
   Hydrometallurgy, 12:151-176,  1984.

4. Ryan, R.  K., and  D. M.  Levins.  Extraction  of
   Radium  from  Uranium  Tailings. CIM Bulletin,
   October,  1980,  pp.  126-133.

5. Levins, D. M.,  R. K. Ryan, and Strong. Leaching
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   Stabilization and   Environmental  Impact  of
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6. Shearer, S. D., Jr., and G. F. Lee. Leachability of
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7. Havlik B., J. Grafova, and B. Nycova. Radium-
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   Waste  Solids and Uranium  Rocks  into Surface
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8. Landa, E. R.  Geochemical  and   Radiological
   Characterization of   Soils  from Former  Radium
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   1984.
 9.  Seeley,  F.  G. Problems  in  the  Separation  of
    Radium  from  Uranium  Ore  Tailings.
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 10. Best,  F.  R.,  and  M.  J.  Driscoll  (Eds.),
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 11. Kanno, M. Energy Developments in Japan, Vol. 3.
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 12. Landa, E.  R. Leaching  of  Radionuclides from
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 13. Organization  for  Economic Cooperation and
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 14. Torma, A.  E. A  New Approach to Uranium Mill
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 15. Torma, A.  E.,  N.  R. Pendleton,  and W.  M.
    Fleming.  Sodium  Carbonate -   Bicarbonate
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 16. Torma, A.  E. Extraction  of  Radionuclides from
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 17. Hawley, J. E. Use of Phosphate Compounds to
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 18. d'Aguiar, H. D. Radium Production in America I.
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 19. Landa. E. R.  A Historical  Review of the Radium-
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20. Albert,  R.  E. Thorium:  Its  Industrial  Hygiene
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                                               37

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21. Clark,  D.  A.  State  of  the Art:  Uranium Mining,
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22. Nathwani, J. S., and  C.  R. Phillips. Rates  of
   Leaching of Radium from Contaminated Soils: An
   Experimental Investigation of Radium  Bearing
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23. Borrowman,   S.  R., and  P.  T.  Brooks.  Radium
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24. Dreesen, D.  R.,  M. E. Bunker, E. J. Cokal,  M. M.
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   National  Laboratory,  Los  Alamos,  New  Mexico,
   1983.

25. Hague, K. E.,  and  J. J. Laliberte.  Batch and
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26. Ryon,  A. D.,  F. J. Hurst, and F. G. Seeley. Nitric
   Acid Leaching of Radium and  Other  Significant
   Radionuclides from Uranium  Ores and Tailings.
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   Oak Ridge, Tennessee, 1977.

27. Torma, A. E.,   and  S. Y.  Yen.   Uranium Ore
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28. Williams, J.  M.,  E. J. Cokal, and D. R. Dressen.
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29. Vdovenko, V. M., and Dubasov, Yu. V. Analytical
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30. Seeley, F. G.  Removal  of  Radium and  Other
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31. Scheitlin,  F.  M.,  and  W.D. Bond.  Removal of
    Hazardous  Radionuclides from  Uranium  Ore
    and/or Mill  Tailings:  Progress  Report for  the
    Period October 1,  1978, to September  30, 1979.
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32. Nirdosh,  I., S. V. Muthuswami, M.H.I. Baird, C.R.
    Johnson, and W. Trembley.  The Reducing-
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    from  Uranium Mill  Tailings.  Hydrometallurgy,
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33. Nixon, A., D.  Keller,  K.  Fritze,  A.  Didruczny,  and
    A.  Corsmi.  Radium  Removal  from  Elliot Lake
    Uranium-Mill  Solids  by  EDTA  Leaching.
    Hydrometallurgy,  10:173-186,  1983.

34. Yagnik, S. K.,  M.H.I.Baird, and S. Banerjee.  An
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    Mill Tailings.  Hydrometallurgy,  7:61-75,  1981.

35. Taskayev,  A. I.,  V.  Ya.  Ovchenkov,  R.M.
    Altkaskhm, and I. I. Shuktomova. Effect of pH  and
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    Extraction of  226Ra from Soils. Pochvovedeniye,
    12:46-50,  1976.

36. Phillips, C. R., and Y.  C. Poon. Status and Future
    Possibilities   for  the Recovery  of   Uranium,
    Thorium, and Rare Earths From  Canadian Ores,
    with Emphasis on  the Problem of Radium Part I:
    Ores, Special Problem, and Leachings. Minerals
    Science  Engineering,  12:53-72, 1980.

37. Sedlet, J. Radon and Radium, pp.  219-316. In:
    Treatise  on  Analytical Chemistry,  Vol.  4. I.  M.
    Kolthoff,  and P. J.  Elvmg,  eds. John  Wiley  and
    Sons (Interscience Publishers), New York, 1966.

38. Kluge, E.,  K. H.  Lieser, I. Loc,  and S. Quandt.
    Separation of 230Th  (Ionium) from Uranium Ores
    in Sulfuric Acid and in Nitric Acid. Radiochemica
    Acta, 24:21-26, 1977.

39. Ryon, A.  D., W.  D.  Bond, F. J. Hurst,  F.  M.
    Scheitlin, and F.G. Seeley. Investigation of Nitric
    Acid for Removal of  Noxious Radionuclides from
    Uranium  Ore or Mill  Tailings. In:  Proceedings of
    Two  OECD/NEA Workshops  on  Uranium  Mill
    Management, OECD Nuclear Agency Publication,
    OECD, Pans, France, 1982. pp 139-147.

40. Ambe, S.  and K. H. Liefer,  Coprecipitation of
    Thorium with Barium Sulfate, Radiochemica Acta,
    25:93-98,  1978.

41. Buskin, A.R.  The Chemistry of Hydrometallurgical
    Processes. Span Limited, London, 1966.
                                                 38

-------
42. Merritt,  R.  C.  Extraction Metallurgy  of  Uranium,
   Colorado School of Mines  Research  Institute,
   1971.

43. Kirby,  H.  W.,  and  M.  L.  Salutsky.   The
   Radiochemistry  of Radium,  NAS-NS-3057,
   National   Technical   Information  Service,
   Springfield,  Virginia, 1964.

44. Sebesta, F., J. John, and V. Jirasek.  Extraction of
   Radium and  Barium  Phosphomolybdates  into
   Nitrobenzene  in   the  Presence of  Poly-
   ethyleneglycol. Radiochem,  Radioanal, Letters,
   30:357-364.

45. Sebesta F.,   E.  Bilkova,  and J.  Sedlacek.
   Extraction of  Radium  and  Barium   into
   Nitrobenzene  in the  Presence of  Polyhedral
   Borate  Anions.  Radiochem, Radioanal, Letters,
   40:135-144, 1979.

46. Raicevic,  D.   Decontamination  of  Elliot  Lake
   Uranium Tailing. CIM Bulletin, 1970.

47. Logsdail,   D.H.  Solvent Extraction  and   Ion
   Exchange in the Nuclear Fuel Cycle. John Wiley
   & Sons, New York,  1985.

48. Rulkens,   W.H.,  and J.W.  Assmk,  et.  al.
   Development  of  an  Installation   for  On-Site
   Treatment  of  Soil  Contaminated with  Organic
   Bromine  Compounds.  Conference   on
   Management  of Uncontrolled Hazardous  Waste
   Sites, Washington, DC, 1982.
                                               39

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-------
                                              Chapters
                                 Physical Separation Processes
6.1  Purpose
Radioactive contaminants in soils  and in uranium mill
tailings may be associated  with fine  soil particles  [1-
3]. Separation  of  the fine soil particles  should
concentrate the  radioactive contaminants in fine soil
fractions,  and thus  reduce the  volume of soil  for
disposal, permitting more manageable soil disposal.

The physical  separation  techniques  that can  be
utilized  to  separate  out or concentrate radioactive
contaminants  within  soils  are  discussed in this
chapter. These separation techniques are also utilized
in the pre- or post-treatment  phases  of  chemical
extraction treatment  schemes.  Physical separation
techniques are mechanical  methods for  separating
mixtures of solids to  obtain a  concentrated form of
the desired constituents. Chemical agents are  added
in some cases to enhance the separation process.
Methods for separation by mechanical rather than by
chemical means are  usually low in cost and trouble-
free.  There are  a variety  of  physical separation
techniques, each  with a particle size range; they are
shown in Table 11 along with the physical  attributes
that govern the  separation processes  [4-6].  In  any
given  process a combination  of  these  physical
separation  techniques  is employed  to  achieve  the
required concentration of the desired constituents.

6.2 State of the  Art

Most  of the radium in uranium  mill tailings  occurs in
very fine particles, or slimes. Borrowman and  Brooks
used  physical  separation  techniques  to  separate
tailings  into sand  (coarse  particle)  and slime [1]
Physical  separation of the  tailings, which  contained
radium  levels  of  500  and 450  pOg, resulted  in
coarse  particle  fractions  with  50  and 140  pCi g
radium, respectively.

Garnett et  al.  scrubbed plutonium-contaminated  soil
with wash solution and then used  physical separation
techniques  to  separate  the clean  sand  [2]. Results
from a few of the tests showed that coarse particle
fractions  of the soil can be  cleaned to contamination
levels of  <1, 12, and 86 pCi/g for soils contaminated
with  45,  284,  and  7515 pCi/g  of  plutomum,
respectively.
Treatment  of Elliot Lake  uranium  mill  tailings  in
Canada showed that much of the radium, thorium,
and  uranium  can  be  removed  using  physical
separation  techniques  [3].  The  laboratory  test  at
CANMET  and  bench-scale  testing at the  Denison
Mill  employing  physical  separation  techniques
reduced the  radium contamination  levels in tailings
from  290  and  266  pCi/g  to 57 and  45  pCi/g,
respectively.

Based on a  literature  review,  the following physical
separation  technologies show potential  for  cleaning
soils contaminated with radioactivity:

       screening,  both dry and wet
       classification
       flotation
       gravity concentration

Sedimentation  and  filtration supplement  these
techniques.

All the above physical separation processes are used
extensively in uranium  extraction. Screening, gravity
concentration, and flotation  comprise  part  of the
physical separation methods used  in preparing the
uranium ore for extraction. The prepared ore is then
normally  acid-leached,  and the  particles  are
separated  using  classification and  ion  exchange.
References  7-10  discuss  the physical  separation
techniques   used  in  many  uranium  processing
operations. Shown in Figure  13 is a process used  to
clean  plutonium-contaminated soil  using physical
separation techniques.  In  this process  a variety  of
technologies, including  screening, classification,
sedimentation, and filtration are employed to separate
the soil into  different size fractions and to separate
out the water. Other  processes used  to  decon-
taminate  soil  probably  would  include   some
combination of these.

The state  of  the art physical separation  technologies
are shown in Table 12. As can  be  seen from this
table,  although these technologies  have  been field
demonstrated for radioactive material extraction from
ores,  they have not been used in  remediating any
radiologically  contaminated  sites.  Pilot plant  testing
                                                 41

-------
 Table 11.    Physical Separation Technology and Particle Size
   Physical Attributes
                                                  Microfiltration
                                                  MBI^^H

                                           Ultrafiltration
                                                                [Screen Staining
                                                                               Cyclones/Cones/Drums
                                                                    Slime Tables
                                                                    	     I
                                                                  Liquid Cyclones
                                                                  J	      I
                                                                  Sedimentation
                                                                  n
                                                          Centnfugation
 Size
 and
Density
                                       Ultracentnfugation
                                                                           Mag Separation
                                                                                Pry
       Magnetic
      Permeability
                                                       Magnetic SeparationDry
                                                                    Electrostatic
                                                                     Separation
       Electrical
      Conductivity
        Surface
        Activity
                                                        Foam & Bubble Fractionation
                             Membrane Technology
  Angstroms
  Microns
  Millimeters
                     10
                     10"
                         Ionic Range
102
TO'2
10"5
103
10"
10"
10"
 1
10"
10s
10
10"
106
102
10"
107
103
 1
108
10"
10
 109
 105
1005
                                   Macromolecular _^
                                       Range
                      Micron
                      Particle
                      Range
                      Fine
                     Particle
                      Range
                         Coarse Particle Range
would  be  needed  to determine  their  capability  for
radiologically contaminated site cleanup.

Selection  of the physical separation technology  for
soil cleaning is dependent on  the  properties of  the
contaminated soil and concentration of radionuchdes
in each particle size fraction.

There are several other separation techniques used in
the mining industry,  which will be described briefly  but
not in  detail because of  their limited applicability  for
removing  radioactive  contaminants  from  soils  and
tailings. These  techniques include:

        heavy media separation
        magnetic separation
        electrostatic separation

Heavy media separation techniques use heavy liquids
of  suitable  density to  separate  light and  heavy
                                                particles  [6,11,12].  Heavy media separation  is
                                                possible  if the contaminant  is in loosely  aggregated
                                                coarse   particles.  If the   contaminant  is  finely
                                                disseminated throughout the soil, then this technique
                                                will  not  work. Also, the heavy  liquids used  give off
                                                toxic fumes.

                                                Magnetic  separation [6,11-13] and  electrostatic
                                                separation  [6,11,12,14]  exploit the  difference  in
                                                magnetic  and  conductive  properties  between the
                                                radioactive contaminants  and  the soil  to  effect the
                                                separation. As with  heavy  media separation, if the
                                                contaminant  is  finely disseminated  throughout the
                                                soil,  these separation  techniques are  not  likely  to
                                                work.

                                                6.3  Technologies of Potential  Interest
                                                This  chapter  discusses  the  physical  separation
                                                technologies  mentioned above.  With  the exception  of
                                                    42

-------
 Figure 13.   Pilot
     Soil Feed
'(lot-scale equipment test for soil decontamination. (Reprinted from [2].)


                                                  Clean Soil (+5 mesh)
   Contaminated    j	
   	>|  Scrubber
     Qnl PooH      '	*	
       Makeup
                                                                   Clean Soil (+35 mesh)
                                                                    Underflow

                                                        Hydrocyclone  	y   Clanfuge
     NaOH & Water
                                 	i	
                                  Ultrafiltration

Overflow
4-
i
j Overflow
v
                                  !
                           Reject   I
                           Stream  i
                                  i
                                    To Waste
                                    Treatment
                                              I           I	
                                 Backwash
                                 Stream          Contaminated
                                              |  Soil

                                           Ship for
                                           Disposal
dry  screening,  all   technologies  screening,
classification,  flotation,  and  gravity  concentration--
use  substantial quantities  of water  as part of  the
process. The  final  concentrate must  be separated
from the water before disposal. The separated  water
is  normally  purified and recycled,  thereby  reducing
the  water  usage.  The  solid/liquid  separation
techniques,  sedimentation  and  filtration,  are  also
discussed in this chapter.
In general, one has to be concerned with dust control
for  dry  physical separation  processes  and  the
treatability of liquid wastes which are generated in wet
physical  separation  processes. These are  important
issues that need to be addressed carefully  before
technology selection.
                                          6.3.7     Screening

                                          6.3.1.1   Description and Development Status
                                          Screening  is  the  mechanical  separation of particles
                                          on the basis of size. Such separations  are achieved
                                          using a uniformly perforated surface. Particles  larger
                                          than the  screen openings are retained on the surface,
                                          while  smaller particles pass through. Material retained
                                          on the surface  is the oversize or plus  (+) material;
                                          that  passing through  is the  undersize  or  minus  (-)
                                          material;  and   material passing  one   surface  but
                                          retained  on  a  subsequent  surface is  intermediate
                                          material.  Perfect  separation  is  seldom achieved.
                                          There are always  some undersize particles  left in the
                                          oversize  fraction.  Nevertheless,  an  almost complete
                                          separation  can  be achieved with  the use of a  slow
                                          feed and a consequently  long screening period [6-
                                          8,11,15-17].
Table 12.  State of the Art of Physical Separation Technologies
                                         Field
                                     Demonstration  Radiologically
                        Bench   Pilot      with      Contaminated
              Laboratory  Scale  Plant   Radioactive       Site
  Technology    Testing   Testing Testing    Material     Remediation
                                                                   Remarks
Physical
Separation
- Screening
- Classifica-
tion
- Gravity
concentra-
tion

x x Used
x x Used
x x Used

in
in
in

extraction
extraction
extraction

of
of
of

radium,
radium,
radium,

thorium,
thorium,
thorium,

and
and
and

uranium from
uranium from
uranium from

ores
ores
ores
 -  Flotation
                                                              Used in extraction of radium, thorium, and uranium from ores
                                                    43

-------
Screening is normally limited to materials  larger than
250  microns,  with  finer sizing  obtained  by
classification.  In addition  to size,  there  are  many
factors affecting the passage of the particle  through
the screen, including  screening  efficiency,  particle
shape, angle of approach,  and particle orientation to
the screen. The closer to the perpendicular the angle
of approach,  the  higher  the chance  of passage.
Taggart gives some probabilities of passage related to
the particle size  [8].

The amount  of moisture  in the  feed  also  affects
screening efficiency, as does  the  presence of clays
and other sticky materials.  Damp  feeds screen very
poorly as they tend  to agglomerate and blind  (plug)
the screen  apertures. Screening  must  always be
performed on either dry or  wet material,  but never on
damp  material.  For  best  screening efficiency,  wet
screening is  always  superior:  Finer sizes  can be
processed, adhering fines  are washed  off by large
particles, and  the  screen is cleaned by the flow of
pulp.  There is  no  dust problem.  There is. however,
the increased  cost of dewatering  and drying, and for
this reason dry screening is  preferred.

Particle  size  separation  achievable by   the  basic
screen  types  is illustrated  in  Figure 14.  A common
problem  with  screens  is the blinding of  the  screen
apertures with particles that are just slightly oversize.
The problem increases as  aperture size  decreases,
and it can result in a significant reduction  in capacity.
Blinding  can  often  be minimized  by correct  screen
motion or by a suitable surface material.

Problems caused by small  amounts of  moisture  can
be alleviated  by using  electrically heated   screen
cloths. Although this increases the capital  cost of the
screen,  operating  costs may decrease  because of
longer surface  life. Another  approach is to use a gas
flame underneath and  parallel to  the screen  surface.
With  screens  having apertures between 0.5  and 5.0
mm, ball decks are sometimes employed for cases of
severe blinding.

Screening  equipment  can  be classified  as  either
stationary or dynamic. Figure 15  shows  the  various
screen types, and Table 13  describes them.


6.3.1.2  Potential Applicable Situations
Table 14 describes the typical situations in which the
basic  screen  types are  used.  Grizzly screens are
normally used for separating large pieces  like stones.
The size of particles screened on  grizzly screens can
range from 20 mm to 300 mm. In  most applications a
grizzly is used to separate  large particles,  followed by
other screens  for  finer separation. Sieve  bends can
be used for separation as  low as  50 microns, since
these devices give  sharper separation than  can be
achieved by wet classifiers.
6.3.1.3  Advantages and Disadvantages
Advantages and disadvantages of the various screen
types are included in Table 14.

Advantages - Screens are an inexpensive method for
separating coarse and fine particles.

Disadvantages  -  Screens  are  subject  to  plugging,
thus decreasing  their efficiency.  Fine  screens  are
very fragile  and  clog  easily  with  retained  particles.
High throughput  reduces particle  dwell  time  on the
screen  and  generally produces  a thick  bed of
materials through which fines  must travel to reach the
screen surface.  This  results in decreased  efficiency.
Screens  are noisy, and dry screening  requires dust
control.  To control dust emissions,  dust covers are
used. Most manufacturers can supply fully enclosed
screening, which  can be  connected  to  a  dust
extraction system.


6.3.1.4   Information Needs
The information listed below must be  gathered  and
considered  in  selection  of the screens   and
implementation  of a screening process.

       Particle size distribution of the feed.
       Radionuclide distribution with particle size.
       Moisture content.
       Mineralogical composition.
       Dust control requirement.
       Throughput required.


6.3.2    Classification

6.3.2.1   Description and Development Status
Classification is the separation of  particles according
to their settling rate in a fluid.  Water is  the fluid  most
commonly   used   in   mineral  processing
[2,3,6,8,10,11,13,14,17-19].

Classifiers  typically  produce  two  streams-one
containing the  faster  settling  particles  called  sands
(underflow or oversize) and another containing slow-
settling particles called slimes or overflow.

Classifier types fall into three basic categories:  (1)
nonmechanical,  (2) mechanical, and  (3)  hydraulic.
Functionally,   mechanical   and   nonmechanical
classifiers are similar and differ only in  the means  of
sand removal.   In  hydraulic  types the  character  of
separation  is  different because  of  the  hindered
settling induced by the hydraulic water.

Table 15 illustrates different  classifier configurations.
Mechanical  classifiers are  designated  by  M-S,
nonmechanical classifiers  by  N-S,  and  hydraulic
classifiers by  M-F or  N-F.  All hydraulic classifiers
are of  the  fluidized-bed  type;  some  of  them  use
                                                   44

-------
Figure 14.   Typical separation sizes of the basic screen types. (Reprinted from [6]. Copyright  1982. Reprinted by permission
            of John Wiley & Sons, Inc.)
     Static
                                          Sieve Bends
                                                                                              Grizzly
                                             Inclined
                                         (Mech Vibration)
                                              Inclined & Horizontal
                                              (Mechanical Vibration)
                                   High Speed Inclined

  .;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.!                 ( El 6Ct rOfTia QnBt 1C Vlbr


                                                                                            Grizzly
                                                                                            (Mech )
                                                                Rod Deck
                                                  Probability
                                                                  Rod Grizzly
  "'"'"'"'"'"'"'"'"''
:  Flat ::::::::::::::::::::

                                 Rotary Sifters
                                                        Shaking
  E:   Revolving'''||:i|||^^i:;ffl   Centrifugal
                                                 Trommel

 10 Aim
100 /jm
                                          1 mm

                                              Aperture Size
                                                                  1 0 mm
                                                                                        100 mm
mechanical  means  to  remove  sand.  These  are
identified as  M-F in Table 13. The  table lists ranges
of suitable operating conditions for each classifier.
Hydraulic  Classifier -  With the  hydraulic classifier,
water or air is introduced so that its direction of flow
opposes that  of  the settling  particles.  The  simplest
form  of a hydraulic separator  is the  settling-cone.
Solid/liquid flows  into  the  settling-cone like  a fluid
being poured  into a funnel.  The  heavy, solid-laden
flow exits the bottom, and the liquid flows radially over
the lip of the cone.
The  more  complex hydraulic classifiers are the Jet
Sizer by Dorr-Oliver and the SuperSorter by  Deister
Concentrator  Co.   These   multicompartment,
multiproduct  classifiers  operate  on  the  basis  of
hindered settling.  Each  compartment is served with
low-pressure  hydraulic  water.  The  amount  of
hydraulic  water  is   controlled  so  that  in  each
succeeding compartment  the coarsest particles are
maintained  in  hmdered-settlmg  condition,  and  the
finer fractions pass along.
                                 D-O  Siphon  Sizer  is  a single-compartment type
                                 built  by  Dorr-Oliver.  Sands  are  discharged  by
                                 siphons  extending to  the  bottom  of  the hmdered-
                                 settlmg zone.  A hydrostatically actuated valve controls
                                 the siphon flow. Discharge for an intermediate fraction
                                 from  the upper  column can be obtained  by additional
                                 siphons. Hydraulic water  consumption is  considerably
                                 lower than required for  multicompartment sizers.

                                 Mechanical Classifiers  - In mechanical classifiers,  the
                                 slow-settling  particles  are  carried  away in  a  liquid
                                 overflow,  and the particles  with  a  higher  settling
                                 velocity are deposited on  the bottom of the equipment
                                 and  dragged  upwards  against  the flow  of liquid by
                                 some  mechanical  means.  The  size and quality  of
                                 separation depends on feed  rate,  speed of  removal,
                                 degree of  agitation, and  height of the overflow weir.
                                 Mechanical classifiers  are  widely  used in  closed-
                                 circuit grinding operations and in  the classification of
                                 products   from   ore-washing   plants.  Various
                                 mechanical classifiers are described below.

                                 The  rake classifier utilizes  rakes  which  dip  into  the
                                 settled material  and move it up the incline for a short
                                 distance. The rakes are then  withdrawn  and  returned
                                                    45

-------
 Figure 15.
The basic screen types and their classifications. (Reprinted from [6]. Copyright  1982. Reprinted by permission
of John Wiley & Sons, Inc.)

                                           Screens
                  ,	I	.
                            Dynamic
                                                                                   Fixed (Static)
               Revolving
                              Oscillating
                                                                  Conveying     Grizzly  Sieve Bend Probability
	 J
Relative [ *+.
Particle/Screen i \_J
Motion Revolving

r
Rotary
i
1
Reciprocating
__ J
i ^
j Motion of [ C *D
Surface v- -

L
Flat
r
i
Sifters Shaking
1
Gyratory
J J

i Motion in Plane of Screen

J
t
Casting
Vibrating
i
Horizontal
1
Re
Gri;

Flow
1 Rotation
j
Motion in Plane
0
Along and

II
.zly
1
Inclined
I
1
Counterflow
Rotation
o
Perpendicular to
1
Traveling
Belt
1
Probability
Electric
Vibration
1 j
Screen i
to the starting point, where the cycle is repeated; the
settled material is thus slowly moved up the incline  to
the discharge.

Spiral classifiers use a continuously revolving spiral  to
move the sands up the slope. They can be operated
at steeper  slopes  than the  rake classifier,  which
results in drier product. Also, there is less agitation  in
the pool, which is important in separations of very fine
material.

A  sedimenting centrifuge  consists  of a  bowl  into
which a suspension is fed and rotated at high speed.
The liquid  is removed through  a skimming tube  or
over a weir while the  solids  that  remain in the bowl
are  removed  either  intermittently or continuously.
Centrifugal  sedimentation is  based  on  a density
difference  between solids and  liquids; the  particles
are subjected to centrifugal  forces which  make them
move radially  through the liquid  either  outwards  or
inwards, depending on whether they  are  heavier  or
lighter than the  liquid.

There are  a variety of bowl  designs  and discharge
mechanisms available for industrial centrifuges.

Drag classifiers  are   single  endless  belt  or  chain
suspensions with cross flights  running in an inclined
trough.  They have  long been used for draining and
classifying.  They  may be any of a variety of shapes
and sizes.

The countercurrent  classifier is an  inclined,  slowly
rotating  cylindrical  drum;  continuous  spiral  flights
                                          attached to the  interior  of  the  drum  form  helical
                                          troughs. The direction of rotation is such that material
                                          in  the  troughs  moves  toward the higher end. Wash
                                          water introduced at the upper end drains  from  the
                                          lifting  flights  above the  normal  water  level  and
                                          progresses countercurrent to the material toward  the
                                          overflow.

                                          The  countercurrent  classifier is  normally  used  for
                                          sand-slime  separations,  washing,  and for  closed
                                          construction restricting escape of  heat and  chemical
                                          fumes.

                                          The  air classifier,  similar  to the hydrocyclone  (to be
                                          discussed  in the  next chapter  on  nonmechamcal
                                          classifiers)  uses air to  produce  coarse  and  fine
                                          fractions. The air classifier is used where solids must
                                          be kept dry, for example, in cement grinding.

                                          Nonmechamcal  Classifiers  -  Nonmechamcal
                                          classifiers rely on  gravitational or centrifugal force to
                                          separate the coarse particles. The  hydrocyclone,
                                          settling  cone, and elutnator are three types that  are
                                          commonly used.

                                          A hydrocyclone  is a widely used,  small, inexpensive
                                          device that gives relatively efficient separation  of fine
                                          particles in dilute suspension. The  hydrocyclone is  a
                                          continuous-operating  classifying  device,  which
                                          utilizes centrifugal force to accelerate the settling rate
                                          of  particles. It is one of the most  important devices
                                          used  in  the  minerals  industry; there  are  over  50
                                          hydrocyclone manufacturers in the world.
                                                   46

-------
Table 13.The Major Types of Screens. (Reprinted from [6]. Copyright  1982. Reprinted by permission of John Wiley & Sons,
        Inc.)

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Heavy duty
surface of
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Probability
Surface of
rotating rolls
Slurry feed. Straight or
fixed bar curved surface
surface
Trommel
Screen surface Centrifugal
rotating around
cylinder axis
Probability
Inclined
(Subclassified
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mechanisms)
High speed
motion,
designed
primarily to Horizontal
lift particles
off surface
Probability


Slow linear
essentially in
Reciprocating
Circular motion
applied to Gyrating
screen surface
Gyrating
Description
Heavy bars running in
flow direction, sloped to
allow gravity transport
length to minimise
blinding
Bars divergent in
vertical plane
Essentially a stationary
screen surface but non
uniform shape of rolls
conveys material
Stationary parallel bars
at right angles to slurry
flow Surface may be
straight (with steep
incline) or curved to
300
Slightly inclined
cylindrical screen May
have concentric surfaces
Vertically mounted
cylindrical screen
centrifuges particles
through screen
Particles drop through
surface formed by bars
radiating out like spokes
on a wheel
Inclined rectanqular
screening surface which
allows material to flow
with aid of vibrations
Horizontal rectangular
Linear vibration must
have horizontal component
to convey material along
screen
Series of relatively
small inclined screen
statistics rather than

Usually slightly inclined
apertures
Rectangular screen
surface with slight (^5)
incline
Circular screen surface
Circular screen surface
Speed
Motlon Amplitude

Stationary surface
(Vibrating grizzlies also
available bar vibrating


Stationary
Below critical speed 1 5 20
(c f ball mill) r p m
Operates above critical
speed Also has vertical 60 80
action of 800 1000 r p m
cycles mm
Radiating bars rotate
about vertical axis
Speed of rotation
determines cut size
Mechanical vibrations
give circular motion at 6QO OOQ
center elsewhere it r m
depends on vibrator r p m
Electro .
 K . Low
magnetic vibrators may s~yz>
give linear vibration
at center
Linear motion, with 600 3000
provide lift, and
horizontal component for Low
conveying ' 25 mm



Linear motion, 30 800
to remain in contact 25-1000
with screen surface mm
Circular motion is
applied at feed end and
produces reciprocating
motion at discharge end
500 600
Circular motion over ' p m
most of the screen
surface Low
Screen moves with
circular motion but
also has oscillating
vertical component
Applications

Scalping before crushers

Coarse separations before
crushing Primarily a
conveyor
Separations in range
2 mm to 45 Mm or those
too coarse for
hydrocyclone, or where
density effects make
classifier unsuitable
Dewatermg
Wet or dry separations
60 to 10 mm if dry
smaller if wet
Wet or dry separations
1 2 mm to 400 Lim
Dewatermg
Developed for separating
coal "^6 mm
Wide applications,
generally down to 200 >jm
in mineral industry but
down to 38 jm m
chemical industry using
the high speeds
Similar to inclined
screens

screens

Down to 1 2 mm for coal
down to 250 Mm
Generally used for finer
separations (12 mm to
45 Mm, wet or dry) m
non-metallurgical

Advantages and
Disadvantages

Simple, robust
Probability form blinding
resistant

Conveying action allows
near horizontal operation
in low head room
situations
Relatively high
efficiency and capacity
Sharpness of cut less
than true screen
Separation slightly
affected by mineral
density Excessive
dewatenng can be a
problem
Simple, useful for
scrubbing or rough size
separations High wear
low surface utilisation
High wear
Relatively high capacity
with fine separations
Cut size easily changed
and controlled by varying
speed
Relatively high
efficiency and capacity
but capacity generally
inadequate below
200 urn
Similar to other
vibrating screens but
can also be used where
head room is restricted
Generally superior to
conventional vibrating
screen High capacity
space, low noise, low
at low loading
Low headroom and power
requirements May be
used for conveying and
maintenance cost, low
capacity

Suitable for finer
separations, but with
low capacity

                                                      47

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 Table 14.Types of Screening Operations and Equipment. (Reprinted from [6J. Copyright  1982. Reprinted by permission of
         John Wiley & Sons, Inc.)
                  Operation and Description
                     Type of Screen
 Scalping: Strictly, the removal of a small amount of oversize from a
 feed that is predominately fines Typically the removal of oversize
 from a feed with, approximately, a maximum of 5% oversize, and a
 minimum of 50% halfsize.
Coarse, grizzly.
Intermediate and fine: same as used for separations
 Separation, Coarse Making a size separation at 4 75 mm and
 larger
 Separation. Intermediate: Making a size separation smaller than
 4 75 mm and larger than 425 micron
 Separation. Fine  Making a size separation smaller than 425 micron.
Vibrating screens, horizontal or inclined.

Vibrating screens, high-speed, sifter, and centrifugal screens Static
sieves
High-Speed, sifter, and centrifugal screens. Static sieves
 Dewatering  Removal of free water from a solids-water mixture.
 Generally limited to 4 75 mm and larger.
Horizontal vibrating, inclined (about 10), and centrifugal screens
Static sieves.
 Trash Removal. Removal of extraneous matter from a processed
 material Essentially a form of scalping operation Screen type will
 depend on size range of processed material
Vibrating screens; horizontal or inclined. Sifter and centrifugal
screens. Static sieves.
 Other Applications: Desliming, conveying, media recovery,
 concentration
Vibrating screens, horizontal or inclined. Oscillating and centrifugal
screens. Static sieves.
 A  typical hydrocyclone  (Figure  16)  consists of  a
conical vessel  open  at  its  apex,  where underflow
discharge  occurs, joined to  a cylindrical  section,
which  has  a tangential feed  inlet.  The  top  of  the
cylindrical  section is closed,  with  a  plate  through
which  passes an axially mounted overflow pipe. The
pipe is extended into the body of the  cyclone by  a
short,  removable section  known as  the vortex finder,
which  prevents  feed from flowing  directly  into  the
overflow.

 Because of a tangential  inlet, the slurry entering  the
cone  rotates  at  high  velocity,  causing  heavier
particles  to  move to  the wall of  the cyclone and
discharge through the apex  opening. The smaller or
lighter particles  move toward the vortex in the center,
discharging through the overflow.

 The  settling cone is the  simplest form of  classifier.
There are  many different  designs  of  cone.  The
machine essentially consists of a suspended circular
tank,  the base of which is in  the shape of a truncated
cone closed by  a valve. Feed is introduced at the top.
The sand settles  in the  cone, while the water and
slimes overflow  into  a circular peripheral  launder. As
the sand  accumulates in  the  cone,  the weight of the
whole machine  increases. This opens  the discharge
valve. When the  sand  is discharged, the  machine
lightens, automatically closing the valve.

 Elutnation is a  process of sizing  particles by  means
of an upward current of fluid, usually water or air. The
process is  the  reverse  of  gravity  sedimentation.
Those particles  having a terminal velocity  less than
that of the  velocity  of the  fluid  will overflow, while
those particles having a terminal velocity greater than
the fluid velocity will sink to the underflow.
  6.3.2.2  Potential Applicable Situations

  Classifiers can be considered for use  in soil-washing
  schemes. A typical  equipment arrangement is shown
  in  block diagram form in Figure  13.  In  this  figure a
  number of classifiers are  used.

  The  front  end  uses  a  scrubber, which  is  a drum
  washer. A spiral  classifier could also be  used for this
  purpose. A hydrocyclone is  used  at  an intermediate
  location  in the  scheme to separate  the  coarser
  fraction from the finer fraction. A centrifuge is used to
  remove the fines from the finer fraction. Each device
  is  used  to handle  a  particular  size  fraction in the
  process.

   Other classifiers discussed  in  this subchapter  can
  also  be  used; the  application is determined  by soil
  size fraction and solid concentration.


  6.3.2.3   Advantages and Disadvantages
  Advantages  - The  principal  advantages of  these
  classifiers are   their  high   continuous  processing
  capability  and their extensive  industrial  processing
  track  record.  The mining industry relies on them as
  prime  movers in ore  refining and  processing.  Low
  cost per  quantity of material being  processed  and
  equipment reliability  are the  major  reasons  for
  selecting the equipment.

  Disadvantages - A drawback to  classification is that
  soil with  a lot  of clay  and  sandy  soil with  humus
  materials  are very  difficult  to  process.   In  general,
  sandy soils low  in clay and humus constituents with a
  high specific  gravity are successfully processed  with
  the classifiers.
                                                      48

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Table 15.The Major Types of Classifiers. (Reprinted from [6]. Copyright o. Reprinted by permission of John Wiley & Sons, Inc.)
CLASSIFIER iType")
Sloping Tank Classifier (M-S)
(spiral rake, drag)
\jjH^^
Log Washer IW S)
'~' * '  -iiV*\
'"V***^0*
Bowl Classifier (M S)
Hydraulic Bowl Classifier |M F!
Q- f> ^^^
U<>(,sggi^^^D'*
"W 1^^
Cylindrical Tank Classifier (M SI
2r 'ff
^*^%*y#^
Hydrsuhc Cylmdncaf Tank (M Fl
Class.fier
2: 'ff,
Cone Class.fier IN SI
0- r.l
-i\ r i /i
Hydraulic Cone Classifier IM F)
n I
u) II IT
Vil/

DESCRIPTION
Classification occurs near
deep end of sloping,
elongated pool Spiral
rake or drag
pool

classtfiet with paddles

Extension of sloping tank
classifiers with settling
occuring in large Circular
pool which has rotating
mechanism to scrape sands
inwards (outwards in Bowl
Oesiltor] to discharge rake
or spiral

Class.fier Vibrating
plate replaces rotating
Hydraulic water passes
plate and fluidises sands
Effectively an overloaded
thickener Rotating rake
underflow
Hydraulic form of over
loaded thickener Siphon
Sizer IN F) uses siphon to
(otatmq take
Similar to cylindrical tank
classifier except tank is
conical to eliminate need
for rake
Open cylindrical upper
section with conical lower
section containing slowly
rotating mechanism
SIZE (ml LIMITING C(:cn VOL % SOLIDS CMITARIL ITV
W.dth SIZE J Feed POWER S ,TND
Diameter [Max Feed 7* .'^ Overflow (kW) APPLICATIONS
Max Length Sue) lt/hr! Sands APPLICATIONS
Used for closed circuit grinding,
0 3 to 7 0 - w washing and dewatermg, deslimirtg,
mm j. No1 cntlcal particularly where clean dry sands
2 4 to b t in are imPrtant (Drag classifier
(spiral) * M * z lo *u '_ sands not so clean) In closed
(25 mm) 45 to 65 C'rCUIt 9rmdl9 dischar9
give enough lift to eliminate pump
0 8 to 2 6
.-.,;,.. removing trash clay from sand
0 6 to 1 1 to to A|SQ jo fMemove 0|, break down
450 60 agglomerates
4 6 to 11 (100 mm)
Not critical Q^ Used for closed circuit grinding
0 5 to 6 0 150 Mm (particularly regrind circuits)
to 5 0 4 to 8 , 5 where clean sands are necessary
1 2 to 1 5 45 um to R h Larger pool allows finer
225 50 to 60 7, jr separations Bowl Desiltor has
12 (12 mm) (15 to 25 in u D larger pools (and capacities)
Bowl Desiltor) ^o Relatively expensive
Vlb Gives verv clean sands and has
1 2 to 3 7 1 mm Not critical relatively low hydraulic water
to 5 g requirements (0 5 t t sand) One
225 R^k classifiers available for closed
' Relatively expensive
Simple but gives relatively
1 50 ^m Not cnt.cal ^efficient separation Used for
to 5 u /b primary dewatermg where the
3 to 45 45i,m to 0 4 to 8 to separations involve large feed
625 1 1 volumes and sand drainage is not
(6 mm) 15 to 25 critical
14 mm Not cmical Two product device giving very
to 1 075 clean sands Requires relatively
1 0 to 40 45 ,;m to 0 4 to 1 5 to little hydraulic, water (2 ft sands)
(25 mml 20 to 35 closed circuit grinding
600 -m Not critical lo^lly^^ndTimplfcTycan0 ^ ^^
06,037 45., ,o 5,030 None C'ra,'-' utV foI'dTsl.ng
3B,o60 ru-X^*"'"^0'""
400 ^m Net critical
to 10 3 Used primarily m closed circuit
0 G to 1 6 1 0O^m to 2 to 1 5 to grinding to reclassify
(6 mm} 30 to 50
                                                         49

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Table 15.(Continued)
SIZE (ml LIMITING
CLASSIFIER (Type*} DESCRIPTION Dimeter (Max^eed
Max Length Size)
Hydrocyclone (N S)
0 "ill (Pumped) pressure feed - 300 um
"1H] generates centrifugal to
\ / action to give high 0 01 to 1 2 5 um
\ / discharge - (1 400 ^m to
\ / 45 Mm]
V*
Air Separator
^
Solid Bowl Centnfu
^5^
i ~
*o
Scrubber
t...I
r^w-
(N S)
^ Similar shape to hydro
^fe- in^^e "" 32
/ / within classifier M
ev,
ge (M S)
settling forces Slurry  m
Xl1"^ centrifuged against 0 3 to 1 4 1 Mm
(P=^  it rotating bowl and removed
/V fl bV slower rotating helical 1 g (6 mm)
" ^ "M 1 screw conveyor within bowl
Q-
M SI
L/ Essentially a rotating drum
	 J 3 to 10 (150 mml
 tr
Counter Current Classifier (M-FI ^ ^m bi^ ^ ^^
another on spiral -
o^A
Elutnator
Pocket Classifier
;:crTT=
Wv
i ; i

S Sedimentation c
 , |"i water added to flow 0 5 to 3 3 2 mm
^ 1 L-_ essentially horizontally m (spiral type) to
\ P which are conveyed and 1 2
T>
IN Fl
u- Basically a tube with
G_ hydraulic water ted near ^ 4 mm
bottom to produce hindered
Column may be filled with ,-, c
J network to eyen out flow ~ <7 S mm)
Q*
IN Fl
aw^~~~~~ c= A series of classification n R t K n 5 a
1  P / pockets with decreasing 0 5 to 6 0 2 4 mm
1 1 guantit.es of hydraulic . , 
?\/\/ HW range of product sizes ,2 (10 mml
1 i

assifier
ssifier
FEED VL teSedL'S POWER SUITASILITV
(t/hr6) SandsW '^ APPLICATIONS
4 to 35 Small cheap device widely used
to Ann for closed circuit grinding Gives
20 2 to 15 JSim* relatively efficient separations
m'/m,n ores sure of fine Parlicles in dllule
30 to 50 head suspensions
Used where solids must be kept dry,
to 4 such as cement grinding Air
2100 to classifiers may be integrated into
500 grinding mill structure

10 0 4 to 20 to capacity for a given floor space
, 110 used for finer separations
m 'mm 5 to 50
Similar applications to log
1 washer but lighter action
..  to Tumbling (85% critical speed;

Not critical
3 02 Very clean sands product, but
to 2 to 1 5 to relatively low capacity for a
600 19 given size
50 to 65
15 to 35 Simple and relatively efficient
4 075 separation Normally a two product
to 0 4 to 5 for device but may be operated in
120 valves series to give a range of size
20 to 35 fractions
15 to 35 Efficient separations but requires
4 3 t hydraulic water/t sand Used
to 0 4 to 5 to produce exceptionally clean
120 sands fract.oned into narrow size
20 to 35 ranges

                                                       50

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Figure 16.
Hydrocyclone. (Reprinted from [6]. Copyright 
1985. Reprinted  by permission of Pergamon
Press, Ltd.)
                                  Overflow
                                     Vortex Finder
    Feed
  Entrance
                                    Apex Valve
              Underflow
              Discharge
6.3.2.4   Information Needs
The characterization listed below must be considered
in selecting  a classifier  type  and  implementing a
classification process.

        Particle size distribution of the feed.
        Radionuchde distribution with particle size.
        Specific gravity and chemical analysis of  the
        soil.
        Mineralogical composition.
        Characteristics of  the soil
        sand, humus, clay, or silt.
        Composition of the  organics  in  each  soil
        fraction.
        Moisture content.
    -   pH.


6.3.3    Flotation

6.3.3.1   Description and Development Status
Froth  flotation  is  used extensively  in  mineral
processing  to concentrate  constituents  such  as
uranium from ores. Great strides  have been made
both in the  chemical  aspects  of  flotation  and  in
equipment  development. Today  flotation is used for
almost all  sulfide  materials  and is widely used for
nonsulfide  metallic  minerals, industrial  minerals, and
coal.  Flotation  is  the most  economical method for
separating  particles in  the  size  range of  0.1-0.01
mm.

 Metallic ores are normally ground finer than 48 to 65
mesh for  treatment in  froth flotation,  whereas coal
and certain nonmetallic  ores are generally treated by
grinding to  finer than the  10  to 28  mesh range.  As  a
rule, coarser  feed  cannot be  suitably mixed and
suspended  by a flotation machine. Fineness of grind
is determined by the particle size at which the desired
minerals are  liberated from gangue  (waste) particles.
In flotation  machines, the  ore is suspended in  water
by means  of  mechanical  or air agitation  at a pulp
density generally from  15  to 35 percent solids. The
surfaces  of suspended particles  are  treated  with
chemicals called promoters or collectors which render
those  particles   air-avid  and  water-repellent.
Through  the use   of modifying agents,  undesired
minerals  are depressed  or  rendered  non-floatable.
With vigorous agitation  and aeration  in  the presence
of  a frother-a  chemical added to create  bubbles-a
layer of froth or foam forms at the top of the flotation
machine. The air-avid minerals become attached  to
air bubbles and rise to the surface where they collect
m  the  froth  and  are  skimmed  off  [2,3,6,10,
11,13,14,17,20,21].

 Flotation of  sulfide compounds is  well established.
Sulfides  are  separated  using  alkyl  xanthates  or
dithiophosphates. Oxide mineral forms can  be floated
from acid or basic  solutions.

 The pH  level  is established for each  mineral  oxide
type. Oxides  are separated with surfactants. Silicates
and aluminosilicates  accept  ionic  surfactants  in the
same way  as oxides. Salt-type  minerals respond  to
anionic surfactants.

 Promoters or  collectors  are added  with  the  ore  to
enhance  flotation of the particles. The collector also
serves as  a  water-repellent,  which   reduces the
moisture  content of the froth.  Typical collectors for
flotation of metallic sulfides and native metals  are
alkyl xanthates and dithiophosphates. These ionized
collectors are adsorbed on a sulfide  mineral surface,
with bonding through the sulfur atoms.

 In flotation, collectors  of  fluorspar, phosphate rock,
iron ore, and  other  nonmetallics  are likely to be  crude
or  refined  fatty acids  and  their soaps,  petroleum
sulfonates,  and  sulfonated fatty  acids. Cationic
collectors such as  fatty amines and  amine salts are
widely used for flotation of  quartz, potash, and silicate
minerals.
                                                   51

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 Commonly used frothers are pine  oil, cresylic acid,
polypropylene  glycol  ether,  and  5- to  8-carbon
aliphatic alcohols such as methylisobutylcarbinol and
methyl amyl  alcohol.  Quantities of  frothers required
are usually 0.01 to 0.2 Ib/ton.

 Depressants assist  in  selectivity  (sharpness  of
separation)  or  to  stop  unwanted minerals from
floating. A typical depressant is  sodium  or  calcium
cyanide to depress pyrite (FeS2).

 Alkalinity  regulators such as lime, caustic soda, soda
ash, and sulfuric acid  are used to  control or adjust
pH, a very critical factor in many flotation separations.

  The choice  of  reagent  is based on past experience
and trial and error, guided by a sketchy knowledge of
surface chemistry. Over the past  40  years  a good
deal of research has gone into this  problem,  but  a
great  deal more is needed.

 Limited information  is available in  the literature on
flotation cells. Some  fundamental  research into  the
physics of particle  capture  by bubbles is  being
pursued in   several  Eastern  European  countries,
presumably   in  the  conviction  that   a   better
understanding of flotation kinetics will lead to practical
improvements in this technique  [12].

 Mechanical flotation devices are the most  commonly
used.  Often  one type of machine  will be used for
roughing and  another for cleaning.  These machines
provide mechanical agitation  and aeration  by  means
of a rotating impeller on an upright shaft.

 In  addition,  some cells  utilize air  from  a blower to
help aerate the pulp.  In recent years, there have been
dramatic increases in the size of  individual  flotation
cells.

 In  a  cell-type  mechanical flotation  machine, froth
product discharge is obtained by  overflow  with  or
without the use of mechanical paddles.

In pneumatic  flotation machines of both cell and tank
types, mixing of air  and  pulp occurs  in  injection
nozzles. In the flotation column, countercurrent flow  is
established  in the  lower section  of  the column.
Although  extensively  tested,  pneumatic  flotation
columns are not common in industry.

Dissolved-air  flotation involves  the  dissolution  of  air
(or other  gas) into the  liquid while under pressure,
followed by  precipitation. Electroflotation is  another
method to create ultrafine  gas bubbles, but this
technique uses electrolysis.


6.3.3.2  Potential Applicable Situations
 Flotation  cells  can  be  considered for use  in  mill
tailings to reduce the  level  of radioactivity. The
Palabora  Mining  Company  in  South  Africa treats
complex ore using flotation  and physical separation
techniques  to  recover  copper, magnetite,  uranium,
and zirconium [22].

Canadians have used flotation cells to extract radium
from uranium mill tailings [3] and  uranium from Elliot
Lake ore [8]. Research  conducted at the U.S. Bureau
of Mines  shows  that  95%  of  uranium  can  be
extracted  from  sandstone  ores  containing 0.25%
uranium oxide by means of flotation [8].

 Of all the ores treated  by flotation in  the U.S., 66%
were sulfides, 7%  metal oxides and carbonates, 24%
nonmetallic minerals, and 3%  coal  [11]. Although
increasingly used for  nonmetallic  and oxidized
minerals, flotation is primarily used to extract sulfides
of copper, lead, and zinc from complex ore deposits.
6.3.3.3   Advantages and Disadvantages
 Advantages  - If the particle fraction containing  the
contaminants  can be  collected  by  the  froth, then
flotation is a very effective tool. High  separation rates
for fine particles can  be achieved.

Disadvantages - If no suitable additive  (promoter or
collector)  can  be found,  then  flotation  will  not be
effective. New additives may have to  be developed to
permit successful flotation separation  for radiologically
contaminated materials.

Flotation  is  a  complex  process,  depending  for
effective separation  on  particle  size,  rate  of feed,
control  of  chemical  additives, and  handling  of  the
refined  product. The  process  is  also  expensive.
Flotation uses small,  compact  equipment of  lower
capital cost but with higher  operating costs than for
gravity separation equipment.
6.3.3.4   Information Needs
The characteristics listed below must be  considered
in preparing to implement a flotation procedure.

        Particle  size  and  shape  distribution of  the
        feed.
        Radionuclide distribution with particle size
        Characteristics  of the  soil  - clay,  humus,
        sand, or silt.
        Specific gravity  and  chemical analysis of the
        soil.
        Mineralogical analysis.
        Concentration ratio of solids  to liquid forming
        the suspension.
        The nature of pretreatment.
                                                   52

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6.3.4    Gravity Separation

6.3.4.1   Description and Development Status
Gravity  methods of separation  are used  to  treat a
great variety  of  materials.  With the  advent of the
froth-flotation  process,  which  allows the  selective
treatment of low-grade  complex ores, use  of gravity
separation declined. However, in recent years,  many
companies have  been using gravity  separation
methods due to increasing costs of flotation reagents,
the relative simplicity of gravity processes, and the
fact  that  they  produce comparatively  little
environmental  pollution.  One of the world's largest
uranium processing plants,  Palabora Mining Company
in  South  Africa,  recovers both   uranium  and
baddeleyite using gravity separation techniques [22].
Modern gravity techniques have proved to be efficient
for the concentration of minerals having particle sizes
in the 50-100 micron range  [6,8-12,14,17].

Gravity  separation  techniques  exploit differences  in
material  densities  to  bring  about  separation.
Therefore, separation is influenced by particle size,
density, shape, and weight.

All gravity separation devices keep particles slightly
apart so that they are able  to move  relative to each
other and thus separate into layers  of dense and light
minerals.  Gravity  separators or concentrators are
classified  by  the  means   used  to achieve  this
interparticle spacing.  The  type represented  by jigs
applies an essentially vertical oscillating motion to the
solids-fluid  stream.  The shaking  concentrators  or
shaking tables form the second group. These  apply a
horizontal  shaking  motion  to the  solids-fluid  stream
by vibrating the surface. Included in this type are the
shaking table,  the  Bartles-Mozley  concentrator, and
the traditional  miner's pan.  Gravity flow concentrators
such  as sluices and  troughs form  the third type,  in
which interparticle space is maintained by  the  slurry
flowing  down  an inclined  surface. Jigs and gravity
flow concentrators, which  are mainly used in  coal,
beach sand,  and iron  ore  processing, will  not be
discussed  here. However, shaking concentrators
(called tables) used in soil decontamination processes
[23] will be addressed in this chapter.

The shaking table is  the most versatile  of  all gravity
devices that in one pass can  produce a  high-grade
concentrate over a  wide range of  particle sizes. The
shaking table is a relatively old device that  has slowly
evolved. Generally,  shaking tables treat materials finer
than jigs are  able to  handle, but this is achieved  at
the expense  of  capacity;  single  deck  tables  have
relatively  low  capacity for their  cost and  space
requirements.

Shaking tables are  very versatile units,  and are used
for a wide range  of  functions: from  roughing  to
cleaning; from the treatment of sands to slimes; from
the  separation  of  two heavy  minerals to  coal
preparation.

A typical table is illustrated  in Figure 17.  Feed enters
through a  distribution box  along part of  the  upper
edge. The  wash water and  shaking  action spread the
feed out over  the table.  Product  discharge  occurs
along the opposite edge and the end. The  essentially
rectangular table  has an  adjustable  slope of  about
0-6  from the  feed edge down  to  the  discharge
edge. The  surface is a suitably smooth material (e.g.
rubber  or  fiberglass)  and  has  an  arrangement of
riffles,  which decrease  in  height along  their length
toward  the  discharge  end.  Different  duties  may
require  a  different deck size or riffle pattern, and a
range of decks are offered by most manufacturers.

 Figure  17.   Schematic of a shaking  table,  showing  the
            distribution of products. (Reprinted from  [6].
            Copyright  1982. Reprinted by  permission of
            John Wiley & Sons, Inc.)
                                Slurry
                                FeecL
 High Density^
 Mineral
                                         Asymmetric
                                          Head
                                          Motion
                                    o
                               Low Density Mineral
Middlings
Modifications  on  the  basic  shaking table  design
include the Bartles-Mozley separator,  the  Holman
slime table, and the Bartles crossbelt concentrator.
6.3.4.2   Potential Applicable Situations
In the soil  decontamination  processes  installed  at
Heijmans Milieutechniek  and  HWZ  Bodemsanenng,
both in Holland,  tables  are  used  in  separating fine
particles  from extracting  agents [23]. Concentration
by gravity method is limited to those  soils  in  which
the contaminants are relatively coarse and capable of
resisting  breakage and sliming or are associated with
other minerals that may  themselves be separated  by
gravity differential. The concentrate thus obtained can
be  processed  further by extraction.  COG  Mineral
Corporation  Mill in Utah  uses  a gravity separator  as
part of the uranium extraction process [14].
                                                   53

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6.3.4.3  Advantages and Disadvantages
Advantages - Gravity separation  is  highly efficient
and  is  a  proven  process for a wide  range  of
applications. It gives  a  high-grade concentrate over
a wide range of particle  sizes and functions well with
most soil types.

Disadvantages  - A drawback is  its  low handling
capacity:  high throughput  requires multiple  decks.
Gravity  separation  requires clean  water,  so  that if
water is recycled  care must be taken to ensure there
is no slime buildup.

6.3.4.4   Information Needs
The  prerequisite  information   listed below must be
considered  in  preparing  to implement  gravity
separation procedures.

       Throughputs.
       Feed preparation  (natural,  sized,  classified
       hydraulically, etc.).
       Feed density.
       Characteristics of the soil-sand, clay,  humus,
       or silt.
       Particle size  and shape  distribution   of  the
       feed.
       Specific gravity  and chemical  analysis of the
       soil.
 6.3.5    Support Technologies for  Treatment  of
         Liquid Recycle
 Most   mineral-separation  processes  require
 substantial quantities of  water; the final concentrate
 has to  be separated  from  a pulp  in  which  the
 water/solids ratio may be high.  Partial  dewatering is
 performed at various stages in the treatment, so as to
 prepare the  feed for subsequent processes.  The
 separated  water is  purified  and normally recycled.
 Dewatering  is  basically a  solid-liquid  separation
 technique  and  can  broadly  be classified  into  two
 types:

        sedimentation
        filtration

 Dewatering is normally needed in any chemical and/or
 physical separation process and is a  combination of
 several  methods.  The  bulk  of the  water is  first
 removed  by  sedimentation,  which  produces  a
 thickened  pulp  with  55-60%  solid loading. Filtration
 increases  the solid loading to 80-90%.

 With the  exception  of  dry  screening, the various
 technologies require  the feed to be in the form  of a
 pulp.  Each  of  these technologies tolerate  certain
 ranges in the water content beyond which they do not
 work efficiently. Figure 18 shows the limits of variation
 of the water content in feed pulp that can be tolerated
by  screening, gravity  concentration,  classification,
sedimentation (thickening), and filtration.

Also shown in Figure 18 are  limits of water content for
other  mineral   processing operations,  such  as
Figure 18.    Limits of water content variation. (Reprinted
            from [6]. Copyright  1982. Reprinted by
            permission of John Wiley & Sons, Inc.)
     I
   Mining
   Coarse Storage
   Crushing
   Screening
 Fine Storage
       Grinding |
Slurry Transportation
                            Classification
                           Concentration
 0   10   20   30  40   50   60   70   80   90   100
                 Water, Volume %
crushing,  grinding,  storage,  drying,  and  slurry
transportation. Even though these operations may not
apply to a  radioactive soil  cleaning process, they are
shown for clarity.


6.3.5.1   Description and  Development Status
Sedimentation  Technologies  -  Sedimentation
technology  can   be  classified   into  gravity
sedimentation  and  centrifugal   sedimentation
[6,8,10,11,13,17,18,24].

Gravity sedimentation  is  the removal  of  suspended
solid particles from a liquid by settling.

Rapid settling of solid particles in a liquid produces a
clarified liquid, which can  be decanted. A thickened
slurry,  which  may  require further dewatering  by
filtration remains. Very fine particles,  of only a few
microns diameter, settle extremely slowly  by  gravity
alone.

Coagulants and flocculants are added,  producing
relatively large  lumps,  called floes,  which  settle out
more rapidly. There are  several equipment designs
available for sedimentation. These are:

        Deep cone thickeners
        Tank thickener
        High capacity thickeners
        Lamella thickeners

  The most common type of sedimentation  unit is the
 cylindrical  continuous tank thickener with  mechanical
 sludge-raking  arms.   Feed  enters the  thickener
 through a central  feed  well,  and  clarified  liquor
 overflows  around the  periphery.  Thickened  sludge
 (the sludge blanket) collects in the conical  base and
                                                   54

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is  raked by  the  slowly  revolving mechanism to  a
central  discharge   point.   One   of   the  main
disadvantages of  these thickeners is the large floor
area required.

With introduction  of flocculant, the  settling rates of
suspension could  be increased tenfold or  more. High
capacity thickeners  take  advantage  of this  by
providing mechanical  mixing of flocculant  and slurry,
and staged additions of flocculant. The high capacity
thickeners are more expensive to operate  but provide
better performance and use less space.

The  lamella thickener uses a nest of inclined plates,
thus providing  a  large effective settling  area  in  a
compact space.  Flocculants are added  to  aid  the
settling.

Deep  cone  thickeners  are  over  4-meter  conical
containers  equipped  with stirrers  and overflow  and
underflow arrangement. High flocculant dosages are
used to obtain high solid concentrations.

Selective flocculation  is an  important technique  that
uses  a high-molecular-weight  polymer,  which
selectively adsorbs  only one of the constituents of a
mixture. Selective flocculation  is followed  by  removal
of the  floes  of one  component. Selective  flocculation
has  been applied to  the treatment  of  clays,  iron,
phosphate, and potash ores.

Centrifugal  sedimentation  is  appropriate  for slurries
with  very fine particles,  since gravity sedimentation
may be very slow.  Due  to high  centrifugal  forces,
separation   of  particles  occurs  quickly  with  high
throughputs.  The  two  types   of  centrifugal
sedimentation designs are  hydrocyclone  and solid
bowl centrifuges.  Hydrocyclones are  described  in the
chapter on classifiers.

The  solid bowl centrifuge is  a cylinder  into  which
slurry  is  fed  and  rotated  at  high  speed.  The
centrifugal action  forces  the heavier  particles to the
wall  of the cylinder, while the liquid  forms an inner
layer  and  is removed.  The  solids  are removed
continuously  or intermittently. There are several bowl
designs available.

Newly  developed  centrifuges  can separate particles
as  fine  as  0.5  micron. Centrifuges have  been
engineered that integrate  flocculations to ease  solid
removal. The  newer centrifuges   have  abrasive-
resistant coatings, require less power to operate,  and
are quieter than older  versions.

 Filtration -  Filtration  normally follows the  thickening
operation  [6-8,10,  11,13,14,17-19,24] The filtration
process can be classified into three types:

        Deep bed filtration
        Screening
        Cake filtration

Deep bed filtration  uses  a deep bed of  granular
media, usually sand, as a filter. Mainly used in water
and wastewater treatment plants, it is inexpensive but
cannot remove fine particles.

Screens are also used as dewatering media; they are
described in the  previous chapter.

Cake filtration is  the  most widely used dewatering
technique in mineral processing. Cake filtration is the
removal of solid particles from  a fluid  by means  of a
porous medium  that retains the solids  while allowing
the  fluid  to  pass.  The  porous  medium  used  in
industrial  filtration  is  a  relatively coarse  material;
therefore, clear filtrate is not obtained until the initial
layers  of  cake  have  formed.  Factors  affecting  the
cake  filtration operation are:  the filtering  surface,
viscosity of the  filtrate, resistance of the  filter cake
and  filter  media,  and  operating pressure or vacuum
required to overcome the resistance.

Flocculants are sometimes added to aid filtration and
prevent fine particles or slimes  from blinding the  filter
media.

Cake filtration can be  operated in  two basic  modes:
constant pressure or constant rate.  Constant pressure
filtration maintains a constant pressure, but flow rates
fall off as  solid  cake  is  formed and resistance
increases.  Most of the continuous filters operate on
this principle,  using vacuum to provide  the pressure
difference. Constant rate  filtration  requires gradually
increasing pressure   as  the  cake  builds  up  and
increases the resistance to flow.

Cake filtration  systems utilize either pressure filters or
vacuum filters. Pressure filters  are normally operated
in  batch  processing  mode  and vacuum  filters
generally in continuous mode.

Pressure  filters  are  widely  used in the  chemical
industries.  The driving force for  filtration is  the  fluid
pressure  generated by pumping.  Since the filters
work  mainly  in   batch processing  mode  and   are
therefore  labor  intensive,  they have seldom been
used in mineral  processing. New   concepts such as
continuous filter  press  are not   really continuous
operation  systems  but  go through   a  series of
automated cycles.

Another new  development  is  the belt filter press
(Manor  tower  press).  Developed  in  Europe, it  is a
continuous pressure filter  used in  treatment of paper
mill sludge, coal, and flocculated clay slurries [18].

All vacuum filtration techniques  use  a porous  filter
medium to support the filter deposits,  beneath which
pressure  is reduced   by  connection  to a  vacuum
system. The  vacuum filtration  can  be operated  in
                                                  55

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batch or continuous mode. Batch vacuum filters are
rarely used in commercial operation.

The  most widely used continuous vacuum  filters  in
mineral  processing are drums,  discs, and horizontal
filters.  Although  different  in  design,  all  continuous
vacuum  filtration  equipment  is characterized by  a
filtration  surface that  moves by  mechanical  or
pneumatic  means from  a point of  slurry deposition
under vacuum to a point of filter cake removal.

A  typical  drum  filter  essentially  consists of  a
horizontal cylindrical drum that  rotates while partially
immersed in  an  open tank,  into which  slurry  is fed
and maintained in suspension by agitators. The drum
shelf itself is covered with  a drainage grid and  a filter
medium. Vacuum is applied from the interior  of the
drum. As the  drum revolves, the cake is raised above
the liquid  level,  and wash  water,  if  required,  is
sprayed on the surface.

Various  methods are used for discharging the solids
from the drum. The most common form is the  use of
a reversed blast of air and a scraper to  remove the
cake. Another form is the belt discharge, in which the
filter medium  leaves  the drum  and  passes over
external rollers before returning to the drum.

Disc filters  operate in a similar fashion and consist of
a number of  discs partly  immersed  in a  slurry  and
mounted along a hollow shaft, through which vacuum
is applied.  The disc is ribbed and  supports  the filter
media.

The  horizontal  continuous  vacuum  filters  are
characterized by a horizontal filtering surface  in the
form of a belt, table, or series of pans in a circular or
linear arrangement.  Horizontal belt filters have been
rapidly accepted  in the  uranium  mining  industries,
because of their ability to filter heavy dense solids.

One new  development  in  filtration  is  filter cake
pressing, in which a squeezing  action is applied to a
previously formed filter cake  to compress the cake
and  remove  further  moisture.  Steam-assisted
vacuum filtration  is another new technique to reduce
cake moisture [13].

Electrofiltration  is  a new  technique  used  for
separation  of ultra fine particles (up  to 10 microns).
Here the slurry is placed  in a direct current electric
field; the negatively charged particles  migrate toward
the anode,  forming a cake which is further dewatered
by electroosmosis.  In the  cathode, the  slurry  is
filtered through a filter cloth by vacuum filtration.

Membrane  separation is a new technology that uses a
semipermeable  membrane to separate a  solid/liquid
system  into its components. Physical, chemical,  and
electrical means  can  be  applied to  enhance  the
operation. Membrane separation is expensive and so
is  not used in the mining industry. This technique is
usually  used  to  separate very fine particles  (0.1-
0.001   micron)  from  liquid.  A  manganese-
impregnated  acrylic fiber  filter has been used  to
remove radium from a  3 M  NaCI extractant solution
and shows significant promise  [20].  A review  [25]  of
various  membranes for  uranium extraction concluded
that  there  is a  particularly promising  membrane
process called selective membrane mineral extraction
(SMME).  The SMME  system  has  been  shown  to
remove 98 percent of radium  from  water containing
1,500  pCi/l  of  the radionuclide.  The  membrane
techniques can  be  used  with  chemical  extraction
technology  to extract  the  radionuclide  from  the
extractant.
6.3.5.2   Potential Applicable Situations
The  selection of the particular technique depends on
the throughput required,  the  particle size,  and the
density of the materials. Cylindrical tanks are normally
used  as  thickeners  but, because of the large area
required  and the  low efficiency  of tanks, centrifuges
or high  capacity thickeners are appropriate where
there is a space  limitation and  high  throughputs are
required.

Pressure  filters  used  in  the chemical  processing
industry  are  rarely  used  in   mining, as batch
operations  are  expensive; however,  pressure filters
can remove fine particles.

Disc filters, and to a large extent drum filters, are the
mainstay for most  dewatering  systems because of
their  ability to  remove fine particles.  Centrifugal
filtration or  electrofiltration  may  be  used to remove
very fine particles.
6.3.5.3  Advantages and Disadvantages [24]
Advantages - Gravity sedimentation is economical; it
carries low maintenance  and  operating  costs. The
technique has a good  long track  record and  is the
simplest of the sedimentation methods.

Centrifuge  sedimentation  offers high efficiency, high
throughput, and effective separation of fine particles.

One of the main advantages of the drum filters is the
wide  range of design  (method  of discharge,  cloth
design,  etc.) and  operating variation (drum  speed,
vacuum operation,  submergence  cycle,  etc.) that
permits  treatment  of a wide  range of  particles  of
diverse  nature.  Drum  filter operations  are  clean,
continuous,  and automatic  with  minimal operating
labor. Drum filters  are also  low in maintenance  cost.
Drum filters provide for effective washing of filter cloth
and can also handle very thin filter cakes, resulting in
increased  filtration  and  draining  rates  with  drier
products.
                                                  56

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One of the main advantages of disc filters is that they
can  handle large  volumes  of  relatively free-filtering
solids (typically 40-200 mesh range).  It is possible to
handle different slurries on one unit simultaneously by
partitioning the filter tank and using one or separate
automatic valves. The disc  filter  equipment provides
for large filter areas on minimum floor  space.

Another advantage of disc filters is the rapid medium
replacement made possible  by virtue of their  design.
in addition, the capital cost of disc filters per unit area
is generally less than for drum filters.

The main advantage of horizontal filters is that large
tonnage  per  unit area can  be processed  with rapid
dewatering . Cakes ranging  in thickness from  10 mm
to 200 mm can be formed  and  washed.  Horizontal
filtering provides excellent  washing with sharp wash
liquid and filtrate separation. In this respect it is better
than the drum filter. Horizontal filter equipment is very
flexible in operation. Since  in horizontal filtration the
settling of  solid  assists  the  filtration,  horizontal filters
are ideal to handle quick settling slurries.

Disadvantages - Gravity separation is ineffective for
fine particles.  It involves  a long  settling time  and
requires  a large floor  area,  especially  when tank
thicknesses are  involved.  It chemicals are used,
operating costs will increase.

Disadvantages of  centrifuge  sedimentation  include
high capital cost, with a high maintenance cost that is
higher  than  other sedimentation  procedures.
Equipment is  noisy, and is  subject to abrasive wear.
Another disadvantage of centrifuge sedimentation  is
its high power requirements.

 The mam  disadvantage of the drum filters is the high
capital cost.  Also,  certain types of  feed cannot be
handled  by  drum filters,  such  as  quick   settling
slurries. Use of blow-back air and a  scraper  knife to
discharge the filter cake may produce wetter cakes
and greater filter medium wear.

One of the main disadvantages of disc filters is that
they are inflexible in operation. A  good washing of the
vertical cake  surface is  difficult,  and because of
limited cake  drying  time, wetter cakes are  formed.
Some designs result in excessive  filtrate blow back,
causing the cakes to be moist. Also,  the discharge of
thin cakes  is difficult. The disc filter equipment  has no
means of  separating different filtrates if the  unit  is
used to  filter more than  one  slurry  simultaneously.
The rate  of  medium  wear  will  be  high  if  scraper
discharge is used.
The  mam  disadvantage of  horizontal  filters  is  the
heavy  wear and tear  of the flexible drainage  belts,
which  results  in loss of vacuum and poor drainage.
The horizontal filter requires  a large floor area. In the
case  of  belt  filters, only  45%  of  the belt  area is
effective.  Horizontal filters are more expensive  than
drum  filters,  but this  disadvantage is  offset by  the
higher capacity  per  unit area, since horizontal  filters
can handle thicker cakes at higher speeds.


6.3.5.4  Information Needs
The  prerequisite information listed below must  be
considered in implementing treatment procedures.

       Particle  size and  shape  distribution of  the
       feed.
       Radionuclide distribution with particle size.
       Specific gravity and  chemical analysis of the
       soil.
       Characteristics  of  the soil  -  sand,  humus,
       clay, or silt.
       Mineralogical analysis.
       The concentration ratio  of solids to  liquid
       forming the suspension.
       The nature of pretreatment.

6.4  Typical Costs of  Physical Separation
     Technologies

The  cost of the application  of  any of the  physical
separation technologies described  in this  section will
depend upon  several factors. Thus the costs cannot
be reliably estimated for any technology and for  any
site  at this stage,  because most of  the  required
prerequisite information is not available.

Among the cautions must also be included  the  fact
that many, if not most, of the controlling  factors will
be  site-specific.  The  cost for a technology at  one
site  may  be  vastly  different  than  for  the  same
technology applied at another site.

 Despite the  limitations and cautions,  some typical
cost  information is  provided in Table 16  for  the
technologies described  in this  chapter.  The  costs
shown do not  include  cost of transportation  and
disposal  of  concentrated  fractions.  The   cost of
returning  "clean"  treated  material  to  a  site is  not
included.

The  purpose,  capacity,  equipment  and  operating
costs in  1987 dollars,  and  factors affecting both cost
and  capacity  are  presented  for the major  types of
physical separation equipment.
                                                   57

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Table 16. Typical Costs of Major Physical Separation Equipment
These costs obtained from vendors are presented to give some typical costs. They are not intended to be applicable to any particular site. Cost
of returning "clean" treated material to a site is not included.
Equipment
Soil Prep. Package
(grizzly crusher,
screen, feeder)
Screw Classifier
Hydrocyclone
Corrugated Plant
Interceptor
Clanfier
Drum Filter
Centrifuge
Flash Dryer
Flotation Unit
Purpose
To prepare soil for
leaching
Preliminary separation of
coarse and fines
Intermediate Classification
of sand and silt
Gravity separation of siit
and fines
Gravity separation of fines
Removal of all suspended
solids
Removal of unfilterable
solids
To dry settled or filtered
solids
For the selective
separation of fines
Capacity
50 - 600 TPH
10 - 950 TPH
50 - 500 GPM
60 - 1000
GPM
60-6000 GPM
0.5 - 90 TPH
10 -600 GPM
700 - 36K
# water/hr
30 - 1000
GPM
Equipment
Cost in
1987 $
500K-
2500K
9K - 167K
1K-5K
4K - 74K
40K - 520K
50 - 400K
60K - 850K
200K -
1800K
25K - 160K

4 -
3 -
1 -
Gal
2 -
6-
80
77 
Gal
120
15
Gal
Operating
Cost in
1987 $
1/Ton
1ATon
0.30/1000
1/1000 Gal
1/1 000 Gas
 2/Ton
 7/1000
- 21/1000*
3/1000
Factors Affecting Cost and Capacity
Soil type, site conditions, truck access,
dust control
Soil type, availability of water radioactive
shielding, corrosive resistance
Corrosion and abrasion resistance
Corrosion resistance, radioactive
shielding, degree of separation
Same as above
Corrosion resistance, radioactive
shielding, shelter
Corrosion resistance, radioactive
shielding, shelter
Corrosion resistance, radioactive
shielding, multilevel construction,
emissions control
Corrosion resistance, radioactive
shielding
6.5  References

1.  Borrowman,  S.R.,  and  P.S.  Brooks.  Radium
   Removal from  Uranium Ores  and Mill  Tailings.
   U.S. Bureau of Mines Report 8099, 1975.

2.  Garnett, John, et al. Initial  Testing of Pilot  Plant
   Scale Equipment for Soil Decontamination.  U.S.
   Dept. of Energy, RFP 3022,  1980.

3.  Raicevic,  D.  Decontamination  of Elliot  Lake
   Uranium Tailing. CIM Bulletin, 1970.

4.  G.  Weismantle. Liquid Solids Separation  and
   Filtration  -  Current  Development.  Chemical
   Engineering, Feb. 6, 1984.

5.  Roberts,  E.  J.,  and  P.   Stavenger,  et.  al.
   Solid/Solid  Separation.  Chemical  Engineering
   Desk Book Issue, February 15,  1971.

6.  Kelly, E.G., and  D.J. Spottiswood. Introduction to
   Mineral Processing. John Wiley, New York, 1982.

7.  Galkin, N.P. The Technology of the Treatment of
   Uranium  Concentrates.  Pergamon  Press,  New
   York, 1963.

8.  Organization for  Economic  Cooperation   and
   Development.  "Uranium Extraction Technology."
   OECD, Paris 1983.
9.   Clark,  Don A. State of the Art:  Uranium  Mining,
    Milling,  and  Refining  Industry.  EPA-660-2-
    74-038 USEPA, Corvallis, Oregon,  1974.

10. Merritt,  R.C.  The Extractive  Metallurgy  of
    Uranium.  Colorado School  of Mines  Research
    Institute, 1971.

11. Wills,  B.A.  Mineral   Processing  Technology.
    Pergamon Press, New  York, 1985.

12. O'Burt,  Richard.  Gravity  Concentration
    Technology. Elsevier, New York,  1984.

13. Wills, B.A., and R.W. Barley.  Mineral Processing
    at  a Cross  Road -  Problem  and  Prospects.
    Martinus Nijhoff Publishers, Boston,  1986.

14. Mular, A.L., and R.B. Bhappu.  Mineral Processing
    Plant  Designs. American Institute of  Mining,
    Metallurgical and Petroleum Engineers, Inc., New
    York, 1980.

15. Mathews,  Chris  W.  Screening.  Chemical
    Engineering Desk Book Issue,  February 15, 1971.

16. Institute of Mechanical Engineers. Screening and
    Grading   of   Bulk  Materials.   Mechanical
    Engineering Publications Ltd., London, 1975.
                                                 58

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17.  Perry,  R., and C.H.  Chilton. Chemical Engineer's
    Handbook. McGraw  Hill, New York, 1973.

18.  Svarovsky,  L.  Advances  in  Liquid-Solid
    Separation. Chemical Engineering, July 1979.

19.  Poole, J.B.,  and  D.  Doyle.  Solid-Liquid
    Separation. Chemical Publishing Co., New York,
    1968.

20.  Ryan,  R.K.,  and  D.M.  Levins.  Extraction  of
    Radium from  Uranium  Tailings.  CIM  Bulletin,
    October 1980.

21.  Ives, Kenneth J. The Scientific Basis of  Flotation.
    Martinus Nijhoff Publishers, Boston, 1984.

22.  Burt,  R.O. Gravity  Concentration Technology.
    Elsevier, New York,  1984.

23.  Assink,   S.W.  Extraction  Method for  Soil
    Decontamination: A  General  Survey  and Review
    of  Operational  Treatment  Installation.  In:
    Proceeding of 1984 International TNO Conference
    on Contaminated Soil. Martinus Nijhoff Publishers,
    Boston, 1985.

24.  Svarovsky,   L.  Solid-Liquid  Separation.
    Butterworths, Boston, 1977.

25.  Kosarek, L. J. Uranium Extraction and In Situ Site
    Restoration  via Membrane  Technology.  1979
    Mining Yearbook. 1979.
                                                59

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                                            Chapter 7
           Combined Physical Separation and Chemical Extraction Processes
7.1  Purpose and Mode of Operation

Employing physical separation techniques, it may be
possible to decontaminate soil to low  radiation levels
by separating the highly contaminated particles on the
basis of particle sizes. While the coarse soil  particle
fractions might still contain radiation above acceptable
levels, removal of radioactive contaminants from them
might allow return of the soil to the place of origin or
placement  in a nonhazardous  waste  landfill.  While
applying further physical  separation techniques would
not lower the  radiation  levels,  chemical separation
technologies applied to the separated coarse particles
might bring  the treated  soil radiation  to acceptable
levels. This chapter discusses the various combined
physical  and chemical  separation  techniques  that
might be  applied to decontaminate radioactive soils.

7.2  State of the Art

Three physical and chemical  separation techniques
will be discussed:

       soil washing and  physical separation
       separation and chemical extraction
       separation, washing and extraction

Soil  washing and physical separation has been used
in two  pilot plant tests  to  decontaminate  plutonium
contaminated soil  [1] and  to  extract radium  from
uranium mill tailings [2].

Separation and chemical extraction  have been used
extensively in  the  mining  industry, in particular  for
extracting uranium.  Palabora Mines  in  South  Africa
uses gravity  separation techniques followed  by
chemical extraction to separate uranium from complex
copper ores [3-6].

Separation, washing and extraction  have been used
to decontaminate soils [7-10].

Table 17 shows the state of the art of the combined
physical  separation  and chemical  extraction
technologies. All  these technologies are in the pilot
plant testing  stage,  and  none have  been  field
demonstrated with radioactive  material.  Major pilot
plant testing and  development work are needed prior
to application of these technologies to radiologically
contaminated site remediation.

7.3  Technologies of Potential  Interest

7.3.7    Soil Washing and Physical Separation

7.3.1.1  Description and Development Status
This process involves washing the soil with chemical
solution, followed by separation  of coarse and fine
particles [1]. The type of solution used  for washing
will depend  on the  contaminant's  chemical  and
physical composition.

The  process water, which  may  lead  to  radioactive
buildup  in  process  streams, is  treated-preferably
by ion exchange-end the resulting decontaminated
water is recycled.

In  1972  the  Department  of  Energy initiated
laboratory-scale  studies  of  techniques  for
decontaminating  soils  [1]. Experiments  were
conducted  to  evaluate a  variety of chemical  and
physical  separation  techniques. The  techniques
included  chemical  oxidation,  calcination, flotation,
desliming,  heavy  media  separation,  magnetic
separation, wet  and dry screening, and washing.
Based on  laboratory-scale studies, the washing and
physical separation  process  was selected  for  pilot
plant  investigation. The pilot-plant process flow
sheet is shown in Figure 19.

In the  pilot-plant  testing  at  Rocky  Flats,  the
plutonium-contammated soil was  washed  in  a
rotating  drum washer using a pH 11  NaOH  solution
as a washing agent. A trommel screen was  used  to
separate the coarse particles ( + 5  mesh),  and  a
vibrating  screen was  used for further  particle
separation ( + 35 mesh). This was followed by use  of
a  hydrocyclone  and  classification to separate  +10
micron particles. Centrifugation and ultrafiltration were
employed  to separate  the  fine  contaminants.  The
water  was  sent back  for  recycle without  any
purification.

The  results  of  the  pilot-plant  testing   show  this
process  could  have  potential  for  success,  but
                                                 61

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 Table 17.  State of the Art of Combined Physical Separation and Chemical Extraction Technologies
        Technology
          Bench  Pilot
Laboratory  Scale   Plant
 Testing  Testing Testing
    Field
Demonstration Radiologically
    with     Contaminated
 Radioactive      Site
  Material     Remediation
Remarks
 Combined Physical
 separation and chemical
 extraction
     Soil washing and
     physical separation
     Separation and
     chemical extraction
     Separation, washing
     and extraction
                                               Pilot plant development and testing needed for
                                               radioactive materials
                                               Various portions of the process have been
                                               developed for extraction of uranium from ores.
                                               Pilot plant testing and development needed for
                                               radioactive materials
                                               Significant bench scale and pilot plant testing
                                               needed for radioactive material
additional  pilot  development  work  is  needed before
scale-up to production  level. In  pilot-plant  test runs,
soils contaminated  to 45,  284,  7515,  1305, and  675
pCi/g were cleaned to contamination levels of 1, 12,
86, 340,  and  89  pCi/g  respectively,  using  different
processes  (Table  18).  The  coarse  particle  fraction
ranged from 58%  to 87%. The results of  pilot-plant
testing showed the fine soil particle fraction containing
the concentrated contaminants  to  have much higher
levels  of  radiation  than the feed, ranging  from 1440
pCi/g to  90,000 pCi/g. Feed rates  ranged from  45
kg/hr to 120 kg/hr.

Recommendations  based  on  the   pilot-plant testing
were that  applying  multistage  washing and  rinsing
instead   of single  stage  would   be  beneficial.
Hydrocyclones  and  filtration  techniques  were
recommended  for  removal  of  fine  particles.
Centrifuging  of  flocculated  solution   was  not
recommended,  as  the  centrifuge  action  tends to
break the floes.

The Canadians used the  froth  flotation technique to
separate  radium from uranium  mine  tailings  [2].
Results  of their laboratory  testing  and bench-scale
                                   Table 18. Soil Product Plutonium Level from Pilot Plant
                                            Operational
Runa



1
2
3
4
5
Feed
(pCi/g)


45
284
7515
1305
675
Product
Coarse
Fraction
( + 35 Mesh)
0.5
12
86
340C
89
Weight
Fraction
%
__b
58
78
87
58
Fine
Fraction
(-35 Mesh)
1440
1485
90,000
10,800
5.850
Weight
Fraction
%

42
22
13
42
                                   3 Each run represents a different process.
                                   b Not available.
                                   c Attributed to inadequate washing and scrubbing
                                 testing at CANMET show that radium in  uranium mill
                                 tailings can  be  reduced  from 290-230  pCi/g to 50-
                                 60 pCi/g by flotation.

                                 However,  in  the pilot-plant  testing  at  Dennison Mill
                                 using  the same process, the decontaminated tailings
                                 showed radium levels of 123-151  pCi/g.  This  was
Figure  19.    Conceptual soil decontamination process flow sheet (Reprinted from [2].)
                                                                     Recycle Water
                                                         >|   Physical
                                                               Separation
                                                         	)!    Water Recycle  ]
                                                                                 Contaminated     '
                                                                                 Soil
                                                    Return to   <-	  _.
                                                    Landfill
                                                                      Ship for
                                                                      Disposal
                                                      62

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attributed  to  recycling  the  water. Whereas  both the
laboratory and  bench-scale testing  used fresh  city
water with no radium in it,  the  pilot-plant test water
contained relatively high amounts of dissolved radium,
ranging between 586 and 1179 pCi/g.


7.3.1.2   Potential Applicable Situations
The soil washing and physical separation process can
be considered for use  in situations where radioactive
contaminants are  closely associated  with  fine  soil
particles. Better success can be obtained with sandy
soils; humus  soils will be difficult to clean.


7.3.1.3   Advantages and Disadvantages
Advantages - The  process is  simple and  relatively
inexpensive and  should require no  major  process
development.  It  has  achieved some degree  of
separation with clay soil in  pilot-plant  testing [1].

Disadvantages  - The main  disadvantage is that this
process  may not  work for humus soil. Also,  pilot-
plant  development and testing are needed.  The
process  may work only for low level radiologically
contaminated soils; this is  yet  to  be determined  by
pilot-plant  testing.  The recycled  water  must  be
stripped  of radioactive contaminants  or  the process
will become inefficient.
7.3.1.4   Information Needs
The information listed below must be collected and
considered before  implementing  soil scrubbing and
physical separation  procedures.

       Nature of the soil: sandy, clay, humus.
       Nature  of the particle: size,  shape,  specific
       gravity, mineralogical and chemical properties,
       etc.
       Radionuclide distribution with particle size.
       Nature of  the  contaminant-chemical  and
       physical properties.


7.3.2    Separation and Chemical Extraction

7.3.2.1   Description and Development Status
The soil  would first be separated  to fine and  coarse
particle fractions. The coarse particle fraction would
be  acid  leached,  the  radioactive contaminants
stripped  by  solvent  extraction  and separated  by
precipitation  and/or  ion  exchange.   The extractant
would  be cleaned  and recycled. The  fine  particle
fraction  would  be  combined  with  extracted
contaminants and sent to a secure disposal site. The
clean coarse  fraction  would require   appropriate
disposal.

Processes  using solvent  extraction,  ion  exchange,
and acid  leaching, etc., have been used in extraction
of uranium from ores and radium from uranium  mill
tailings [6,11-13]. In mining, since the objective is to
extract  maximum quantities  of the  desired
constituents (uranium and radium) from  the  ores and
tailings, the  leaching is applied to the feed  as  a
whole,  without  separating into  fine  and coarse
fractions. Although the process can be applied to  the
unseparated  soil,  this  may not bring  contaminant
concentrations to  the  acceptable levels.  Since  the
weight fraction of  the  coarse  soil  particle portion
ranges from  60-80% [1], and  since its contaminant
radiation levels will be lower to start with, cleaning  the
coarse fraction  could  possibly  clean  a large
percentage of the soil to acceptable standards.

There  are  several variations  on the above  process.
Two-stage  acid   leaching  instead  of  solvent
extraction  is one variation [14]. Another is to use  ion
exchange  instead of solvent extraction, a technique
used in several uranium extraction processes [6]. A
third variation is to  use a solvent  to extract uranium
and a  salt  solution to extract radium from acid  leach
residues [12].

The  Canadians [14] have  used leaching  solution to
extract thorium,  radium, and uranium  from  uranium
ore.  Two-stage  hydrochloric   acid  leaching was
employed,  which  resulted in mill tailings with radium
levels of 15 to 20  pCi/g.

In Europe,  several solvent extraction techniques have
been used to clean  soil contaminated with cyanides,
heavy metals, and organics [7]. In these processes, it
is the  fine fraction  that receives  the benefit of  soil
cleaning methods, since the contaminants are mainly
associated with  the fine particles. The  estimated
typical  cost to clean  soil in Europe  is around  $100/ton
[7]. This is exclusive of excavation and transportation
costs,  overheads,  profits,  and  cost for safety
measures  [10].

Details of different chemical extraction techniques  are
discussed  in Chapter  5  of  this  report.  Physical
separation techniques that can  be used are discussed
in Chapter  6.


7.3.2.2  Potential Applicable Situations
Separation  and  chemical  extraction   can  be
considered for use  in sandy, clay,  and  humus  soils.
This type  of process  has been  used, with limited
success, to extract  radium from uranium mill tailings
in pilot plant  testing. A  large concentration of sulfide
in the  soil  will have a marked  effect on the radium
extraction  [12].


7.3.2.3  Advantages and Disadvantages
Advantages - An advantage  of this process  over
other methods discussed in this chapter is that soils
containing  higher  levels of  radioactivity  can  be
                                                  63

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treated. Also, various facets of the process have been
developed for extracting uranium, and laboratory work
is  underway  in  Canada for extracting  radium from
uranium mill  tailings.  However, the development of
various facets of a process does not mean the entire
process will work.

Disadvantages  - The  main  disadvantages  of  this
process  are that it  is expensive  and  has  high
chemical usage. The chemical required will  depend
on the soil analysis.  A  problem may arise with high
sulfur content  in the  soil interfering  with  radium
extraction.   Also,  the  process  needs   major
development  work prior to application  in extracting
radium from  soil. In  addition,  the use of chemicals
raises  concerns of plant safety  and  environmental
pollution. This  approach may  not be  successful in
extracting  radium,  thorium, and uranium in  a single
process.


7.3.2.4  Information Needs
The  information listed  below  must be  considered in
implementing treatment procedures.

       Nature of the soil: sandy, clay, humus, silt.
       Physical and chemical properties of the soil.
       Nature  of the  particle:  size, shape,  specific
       gravity,  mineralogical properties.
       Radionuclide  distribution with particle size.
       Nature  of the contaminant:   chemical,
       physical, and mineralogical properties.
       Concentration ratio of  solid to  liquid  forming
       the slurry.
       The  nature of pretreatment.


7.3.3   Separation, Washing and Extraction

7.3.3.1  Description and Development Status
Following  separation, contaminated soils conceivably
can  be scrubbed  with a variety  of washing fluids,
followed  by chemical  extraction.  The  nature  of the
washing fluids  and chemicals would depend on the
contaminants and the characteristics of the soil.  It is
most effective  to separate the  soil  into fine  and
coarse fractions and use the scrubbing system on the
coarser soil  fraction to reduce the throughput  and
chemical usage. The treated coarse soil  might then
be returned to the site. The finer soil fractions and
contaminants could  be sent  to disposal.  Depending
on the soil grain size distribution, reduction in disposal
volume of 60-80% may be possible.

The agents that can be applied to  soil washing are:

        Surfactants that improve  the solubility of the
        contaminants  and the  tendency  for  fine
        particles to separate from  larger ones.
        Chelating additives used  to chemically react
        with metals.
       Acid or alkaline solutions to mobilize and/or to
       improve solubility of the contaminant.

Washing  solutions  are basic  aqueous  solutions
(caustic,  lime,  slaked lime,  or  industrial alkali-based
washing  compounds);   acidic  aqueous  solutions
(sulfuric,  hydrochloric, nitric, citrus, phosphoric,  or
carbonic  acids); or  solutions  with  surfactant  or
chelating  agents.   Hydrogen  peroxide, sodium
hypochlorite,  and other oxidizing agents may also  be
used. A  strong basic surfactant solution  could  be
used  for  organic extraction, and strong  acidic  or
chelating  agent solutions  can  be used  for  metal
extraction.  Strong base or acid might  be used  in
cases of high contaminant concentration,  where the
cost of  chemicals is  affordable and the wastewater
can  be treated for  safe disposal.  Surfactant and
chelating agent soil cleaning are being  developed to
reduce chemical and  equipment costs, make the soil
reusable,  and  simplify  wastewater  treatment. The
surfactant and  chelating solutions have a moderate
(almost  neutral)  pH,  making  equipment  operation
safer.
The EPA Soil  Washing  System,  developed  by the
EPA  Risk Reduction Engineering  Laboratory  at
Edison, NJ,  uses a scrubber  extraction  process to
clean soil. Pilot studies were performed to select the
equipment for the  EPA  soil  washer. Three unit
operations were developed  and  proved by testing:

   Water Knife Concept - A  thin, flat,  high-speed
    water jet breaks  up clumps  of  soil  and  scrub
    contaminants  from larger soil particles like stone
    and gravel. Testing showed that  this concept is
    very effective.

   Rotary Drum  Screener -  A  rotary  drum was
    employed as  a pretreatment to mix the soil with
    the extractant and  separate  the soil  into two
    particle size categories ( + 2mm and -2mm).

   Extraction and Separation  Concept -  A  four-
    stage counterflow extraction  train was  designed
    and built  to treat  the   -2mm  soil  fraction
    separated by  the  drum  screener.  Each  stage
    consists  of a tank,  stirrer,  hydrocyclone, and
    circulating pump. The pump moves the soil from
    one  stage   to  the  adjacent  stage.  The
    hydrocyclone  discharges the soil slurry in the next
    stage and returns the  extractant. The extractant
    flows  by  gravity as a tank  overflows in a stream
    from one tank to another, counter to the direction
    of the soil. Fresh extractant is added to the fourth
    stage, and  spent  extractant is removed from the
    first stage.

A mobile soil washing pilot-plant was built using the
above features [15].  The  pilot-plant  scheme (Figure
20) was  designed for water extraction of  a broad
                                                  64

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Figure 20.    Simplified process flow diagram of the EPA soil washer. (Reprinted from [15).
   Contaminated
   Soil

^
Soil/Size
] Classification
1 System
Oversize
Materials/
Debris
Air cleaner j
'T-
i
j Countercurren
! 	 >| Chemical
! | Extractor
"
Spent j

t 1 Pressure Filter Reclaimed
1 I Drying Bed Soils
-
Recycled
| Solvent 1
Squeezate/
Runoff etc

                                                  Waste
                                                  Sludge
range  of  hazardous  materials  from  spill-
contaminated soils.

The  system  can (1) treat  excavated contaminated
soils, (2)  return  the treated  soil  to  the  site,  (3)
separate the  extracted hazardous materials  from  the
washing fluid for further processing  and/or  disposal,
and  (4)  decontaminate  process  fluids  before
recirculation  or  final disposal.  The washing fluid
(water) may contain additives, such as acids, alkalies,
detergents,  and  selected  organics  solvents  to
enhance   soil  decontamination.  The  nominal
processing rate  will be  3.2  cu  m  (4  cu yd)  of
contaminated soil per hour when the soil particles  are
primarily less than -2mm in size and up  to 14.4  cu
m (18 cu yd)  per  hour for soil of  larger average
particle size.


7.3.3.2  Potential Applicable Situations
The  concept  can be considered for use  with granular
soil.  Clay  and humus soil  may  be  difficult  to clean
using countercurrent extraction.  Pilot-plant testing is
needed to determine the effectiveness of the process.
The  EPA  Mobile Soil Washer was  used  to remove
nonradioactive  contaminants  from  soil.  With
equipment modifications and additions and significant
bench-scale and  pilot-plant  testing,  the unit can  be
considered  for  use   to  clean  radiologically
contaminated soils.


7.3.3.3  Advantages and Disadvantages

Advantages - It is possible that soils can be cleaned
to acceptable  limits.  The  same  countercurrent
decantation technology  has been used in  uranium
extraction.  However, pilot plant testing is needed  to
determine the effectiveness of this process.

Disadvantages  - The  Soil Washing  System  needs
further development to determine washing fluids that
are effective in removing  radioactive contaminants
from soils.

The  most  suitable  type of washing  fluid must  be
determined using a bench-scale  test for each soil. A
process to clean the contaminated  washing fluid  for
recycle must  be established  through  pilot-plant
testing. The process may not work for clay or humus
soils.  Significant  bench-scale  and pilot-plant testing
is needed.


7.3.3.4  Information Needs

The soil and contaminant characteristics listed below
must  be  considered  in  implementing  treatment
procedures.

       Nature of the soil: sandy,  clay, humus.
       Nature  of the particle: size, shape, specific
       gravity,  mineralogical and chemical properties,
       etc.
       Radionuclide distribution with particle size.
       Nature  of  the  contaminant:  chemical  and
       physical properties.

7.4  Typical Costs of Separation  and
     Extraction Technologies
It must be  noted that  most  of  the  cost controlling
factors for cleaning  soil using  the  separation  and
extraction  technology will be site  specific. In addition,
the combined technology has not been demonstrated
to  clean radiologically contaminated sites. Since the
                                                  65

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detailed process information  is lacking,  the  cost for
this technology cannot be reliably estimated.

However,  the  estimated  typical  cost for cleaning
nonradioactive  contaminated  solid using  separation
and  extraction  technology  ranges  from  $45  -
$100/ton  (1985 $)  [7],  exclusive  of  excavation,
transportation,  and disposal  costs for all fractions.
These costs are not intended to be applicable to any
particular  site.   Costs of  returning  "clean"  treated
material to a site are not included.

7.5  References

1.   Garnett,  John,  et al. Initial  Testing of  Pilot Plant
    Scale  Equipment for  Soil  Decontamination,  US
    Dept. of  Energy, RFP 3022, 1980.

2.   Raicevic,  D.  Decontamination  of  Elliot  Lake
    Uranium Tailing. CIM Bulletin, August 1970.

3.   Wills,  B.A. Mineral  Processing  Technology.
    Pergamon Press, New York, 1985.

4.   Wills, B.A.,  and R.W.  Barley.  Mineral Processing
    at  a Cross Road  -  Problem  and  Prospects.
    Martinus Nijhoff Publishers,  Boston, 1986.

5.   Merritt,  R.C.  The  Extractive  Metallurgy  of
    Uranium. Colorado  School of Mines  Research
    Institute, 1971.

6.   Clark,  Don  A.  State of the Art: Uranium Mining,
    Milling,  and  Refining   Industry.  EPA-660-2-
    74-038 USEPA, Corvalhs, Oregon, 1974.

7.   Assink,  S.W.  Extraction  Method  for  Soil
    Decontamination: A General Survey and Review
    of  Operational  Treatment  Installation.  In:
    Proceeding of 1984 International TNO Conference
    on  Contaminated  Soil.  Martinus Nijhoff Publishers,
    Boston,  1985.

8.   Schulz,  Robert, and Joseph  Milanowski. Mobile
    System for Extracting Spilled Hazardous Materials
    from Excavated  Soils. In:  Hazardous Materials
    Spill Conference, Milwaukee, Wisconsin, 1982.

9.   Rulkens, W.H., and J.W.  Assink, et. al. Extraction
    as  a  Method  for Cleaning Contaminated  Soil:
    Possibilities,  Problems  and  Research.  In:
    Conference  on  Management of  Uncontrolled
    Hazardous Waste Sites, Washington, DC, 1984.

10. Rulkens, W.   H., and  J.  W.  Assink, et. al.
    Development  of an  Installation  for  On-Site
    Treatment  of  Soil  Contaminated  with  Organic
    Bromine  Compounds.  In:  Conference  on
    Management of  Uncontrolled  Hazardous Waste
    Sites,  Washington DC, 1982,
11. Logsdail,  D.H.  Solvent  Extraction and  Ion
   Exchange in the Nuclear Fuel Cycle.  John Wiley
   & Sons, New York, 1985.

12. Ryan,  R.K.,  and  D.M. Levins.  Extraction  of
   Radium  from  Uranium  Tailings.  CIM Bulletin,
   October 1980.

13. Ives, Kenneth J.  The Scientific Basis of Flotation.
   Martinus Nijhoff Publishers, Boston, 1984.

14. Perry, R., and C. H. Chilton. Chemical  Engineer's
   Handbook. McGraw Hill, New York, 1973.

15. Traver,  R.  D.,  In-Situ Flushing and Soil Washing
   Technologies   for   Superfund   Site.
   RCRA/Superfund  Engineering,  Technology
   Transfer Symposium, 1986.
                                                 66

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                                             Chapter 8
             General Issues at Radiologically Contaminated Superfund Sites
8.1  Introduction

This chapter discusses some of the issues likely to
be associated  with remediating Superfund  sites that
contain radioactive materials. The  discussion is not,
by any means,  comprehensive. These issues include:

       disposal siting;
       handling of concentrated residuals;
       site information needs;
       mixed wastes;
       public reaction and acceptance; and
       costs.

8.2  Disposal Siting

Every site remediation involving radioactive materials
must  include a final,  environmentally  safe disposal
site for the radioactive materials. The total  activity of
the radionuclides will  not  be  lessened  by  any
remediation  process, although the  matrix  in  which
they are included may be reduced in  volume by  some
of the technologies discussed.

Site selection for disposing of radioactive materials is
already a sensitive issue. As noted in the discussion
of land encapsulation  in  Chapter 2,  states are
beginning  to restrict the use  of  land  within  their
borders  for  the  disposal of commercial  low-level
waste from other states.

Any  disposal site for  radioactive waste  must  be
selected  or  constructed  such  that  it  contains the
radionuclides  as  long as their  concentrations are
unacceptable for release  to the environment.

There are several  guidance documents available from
EPA  that  provide  information  that  should  be
considered in selecting the location of a disposal site
[1-4].

8.3  Handling of Concentrated  Residuals

Chemical  extraction   and  physical  separation
techniques applied to soil to remove radionuclides are
intended to clean  the soil and reduce the volume of
contaminated materials.  If that is  done,  there will be
fractions  in  which the  radionuclides will  be   much
more  concentrated--!.e.,  the radioactivity  per unit
volume will be much higher. Handling and disposal of
the concentrated  materials will  require precautions
appropriate  to  the  activity  level.  DOT and  NRC
regulations for containment and storage of radioactive
materials provide guidance for this situation.

Final disposal may be even more  difficult after volume
reduction than it would be if the  material were  to be
excavated,  transported,  and  disposed  of  without
treatment for volume reduction.  In  addition the
"clean"  fractions  may  contain  traces  of  toxic
chemicals used in the treatment  process, along with
some  traces of  the radioactive  contaminants.
Therefore,  these  fractions  also  may  require
environmentally safe disposal.

Any attempt to  put "cleaner"  soil off site is likely to
meet with the same resistance as locating a disposal
site for  all the  material in the first place. The goal
would be to have  a portion  clean enough  to be
replaced at the site.

8.4  Site Information Needs

For many sites,  available  information is  limited
regarding the  detailed  physical, chemical,  and
mineralogical characteristics  of the matrix  materials
associated with the radioactive contaminants. In  some
cases,  even the nature of the radionuclides present
does not  appear  to  be  known with certainty.  More
detailed information is essential  if  use of  chemical
extraction and/or  physical separation  techniques  is
considered.

8.5  Mixed Wastes

Sites  that contain radioactive  waste  materials  may
also contain other types of hazardous waste. Some of
the  Superfund  sites contain  various types  of
hazardous  wastes  and the  radioactive  portion  may
pose a  relatively  minor threat by comparison. The
presence  of  other hazardous  materials   may
complicate dealing with the radioactive  portion of the
waste and vice-versa. This  is an issue  that is likely
to arise at many  Superfund  sites and  would impact
the possible utility  of  some of  the  remediation
technologies. The disposition  of waste containing both
                                                 67

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radiological  and  chemical constituents  ("mixed
wastes") poses unique problems that will have  to be
addressed early in the technology screening process.

8.6  Public Reaction and Acceptance

Public concerns with respect to Superfund  sites may
be  magnified  where  radioactive wastes  exist.
Concerns  can  be  expected   regarding  the
contaminated site, moving the material  (if necessary),
any  processing or treatment location,  and  final
containment.

8.7  Costs

All methods  with the  exception of  in situ techniques
will  involve  excavation  costs for the  materials.
Application of some of the technologies may result in
a  reduced volume  of radiologically  contaminated
materials to be sent to a  secure disposal suitable for
such  materials. The  cost  of  such disposal  would
include  transportation  and  land encapsulation.  The
"cleaner" fractions  remaining after  a  treatment
process is completed  must be analyzed for residual
contamination and evaluated for replacement  at  the
point of origin or at a suitable alternative site. There is
a cost associated with this placement.

Costs associated with a treatment  technology can be
divided  into  development and  implementation  costs.
Development costs  include several stages  of
laboratory tests, studies and process designs leading
to pilot-scale testing,  and  final  design.  Additional
development  costs  involve  fabrication, shakedown,
and  final testing  of a  full-scale system  under
controlled and  field conditions. These costs  could
range  from  under $1  million  for a  small  system
applicable to  one specific type of  problem  to  many
millions  for  a larger  system   with numerous
subsystems,  and  applicable to numerous types  of
problems.

Implementation  costs  when a treatment  option  is
chosen for  a given  site  include  mobilization and
demobilization, and operating costs. The mobilization
costs include  all  costs  associated with  performing
site-specific  laboratory   and/or pilot-scale testing;
selecting  an  operating  site;  preparing any permit
application  materials   or other administrative
documentation  necessary for  operations; interface
with local, state, and federal officials for such permits;
transportation, setup, and shakedown of the treatment
system on the  site  (including  any  site modifications
such as installation of water supply  wells, power, road
access,  operating areas, buildings, and other such
logistical  site  features);  performing  site-specific
testing to determine if the full-scale system performs
according  to  the  laboratory   and pilot-scale
predictions;  and any  other pre-operating types  of
costs.  Mobilization costs  may range from  a few tens
of thousands of dollars  for a simple,  small site to
multiple millions at a  site  with  a large,  complex
installation where complicated permitting issues  have
been involved.

After operations are complete,  demobilization costs
incurred  include   those  associated   with
decontamination of the entire system and surrounding
operating  site,  disassembly  and  transport  of the
system, final  determination and documentation  that
the treatment site has met the ARARs and has  been
brought to a state protective of human health and the
environment,  preparation of  operations documenta-
tion, and  any  other site-specific  costs  associated
with the post-operation  period.  These  costs  can
range from a few  tens of thousands of dollars to  a
million  dollars  or more,  depending  upon  the
complexity  of the  installation  and  the  degree of
contamination.

Operating  costs include all those labor and  material
costs needed to operate the treatment system at the
site, sometimes on a  24  hour-per-day  basis; to
provide  for site security and personnel  safety; to
maintain  record-keeping  including  permit-related or
mandatory  administrative documentation  for  all  site
actions; and to maintain the system in good operating
order.  The costs  per  ton or per cubic  yard  must
include all   applicable  operating  costs.   These
operating costs per cubic yard  are dependent  upon
the  capacity  of  the  treatment  system and  the
percentage of the time that the system is operating as
opposed to being in a maintenance  mode.

Operating costs depend largely upon the cost of  labor
at the  site.  Special protective  clothing and  special
handling  of the contaminated materials (particularly
the concentrated  materials)  could  raise labor costs
well above  those  that  might  be expected  for  a
comparable crew  size  working   at a  nonradioactive
Superfund site. Some costs  may be  reduced due to
efficiencies  in   personnel  monitoring  and
decontamination of workers and  equipment compared
to  some of  the  lengthy procedures  required for
hazardous chemicals, since radiation is relatively easy
to measure, especially compared to many chemicals.

Overall, the operating  cost,  if  it  is assumed to be
similar  to  on-site  incineration operations would
probably range from several hundred dollars per cubic
yard for a large,  high-capacity   system with a  high
percentage of  operating  time,  to  several thousand
dollars  per cubic  yard  for smaller capacity  systems
having  numerous maintenance problems and a  large
crew.

The costs  must include  disposal  costs  for
concentrated  material and will be highly  dependent on
how far treatment must be taken to allow unrestricted
disposal of the "cleaner" portion.
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The costs of treatment for individual sites and groups
of similar sites can be  examined in further detail to
determine the likely costs of such treatment and how
those costs compare  with the  costs of transportation
off site and land encapsulation.

8.8  References

1. U.S. Environmental Protection Agency. Combined
   NRC-EPA  Siting Guidelines  for Disposal  of
   Commercial Mixed  Low-Level Radioactive and
   Hazardous  Waste,   OSW-USEPA. March  13,
   1987.

2. U.S. Environmental Protection Agency. Criteria for
   Location  Acceptability  and  Existing Applicable
   Regulations - Phase  I - Permit Writers' Guidance
   Manual for Hazardous Waste Land  Storage and
   Disposal  Facilities,   USEPA. OSW-Fmal  Draft,
   February 1985.

3. U.S. Environmental Protection Agency. Criteria for
   Identifying  Areas of Vulnerable  Hydrogeology
   under RCRA -  Statutory Interpretive Guidance -
   Guidance Manual  for  Hazardous Waste Land
   Treatment,  Storage, and  Disposal  Facilities,
   OSW-USEPA, Interim Final,  July 1986.

4. U. S.  Environmental  Protection  Agency.
   Standards  for Cleanup  of  Land  and Buildings
   Contaminated with Residual Radioactive Materials
   from  Inactive Uranium Processing  Sites.  40 CFR
   192.12, 48  FR 602. January 5, 1983.
                                                69

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                                                 Chapter 9
                                     Criteria for Further Studies
9.1  Introduction

Any choice of remediation technologies for radioactive
wastes at Superfund  sites would have to  be site-
specific. Since  none  of the chemical  extraction  and
physical separation technologies has been used in a
site  remediation situation,  their  application  must  be
approached  cautiously.  The  same  holds  true  for
solidification  or  stabilization  processes.  Essentially,
only land encapsulation has been used to remediate
similar sites; ocean disposal has been used for low
level radioactive wastes  [1-3].
9.2 Alternative Assessment Studies

A  complete  site  characterization  would  include
mineral analysis, particle size distribution, radionuclide
contaminant distribution on various size  fractions, soil
texture and permeability, moisture content, etc. A list
of some important site and waste characteristics  that
may affect  the applicability and effectiveness of
various technologies is presented in Table 19 [4].

Since further developments and  studies  on alternative
technologies for each Superfund site  may  be very
expensive,  it is important to study  the  patterns in
waste  characteristics  at  various  sites  and  develop
waste   groups  with  similar  major  characteristics.
Alternative assessment  studies  can be  used to help
select  the alternative technologies to treat each  waste
group. Thus, a  preliminary screening of technologies
can  be accomplished based primarily  on  the  waste
characteristics.

Based on these alternative assessment studies,  one
or more technologies, individually or in combination,
can be selected for further investigation.
Physical separation and  combined physical separation
and  chemical extraction  techniques  will not apply if
radionuclides are uniformly distributed through all the
soil  size  fractions. This,  however,   is  unlikely.  The
highest concentration  of radioactive materials appears
to be contained  in very fine particles [5,6].

Chemical extraction technologies  may be applicable
to tailings  and  contaminated soils but  may not  be
applicable  to  building  debris   and  contaminated
Table 19. Site and Waste Characteristics that Impact
         Remediation Technologies
Site Characteristics
Site Volume
Site Area
Site Configuration
Disposal Methods

Climate
   -   Precipitation
   -   Temperature
   -   Evaporation
Soil Texture and Permeability
Soil Moisture
Slope
Drainage
Vegetation
Wasfe Characteristics
Quantity
Chemical Composition
Mineral Composition
Acute  Toxicity
Persistence
Biodegradability
Total Radioactivity

Radioisotopes and Concentration
Ignitability

Reactivity/Corrosiveness
Treatability
Thermal Properties
Depth of Bedrock
Depth to Aquicludes
Degree  of Contamination
Cleanup Requirements
Direction and Rate of Ground-
water Flow
Receptors
Drinking Water Wells
Surface Waters
Ecological Areas
Existing  Land Use
Depths of Ground Water
or Plume
Infectiousness
Solubility
Volatility
Density
Partition Coefficient
Safe Levels in the Environment
Compatibility with Other
Chemicals
Particle Size Distribution
Radioactivity Distribution with
Particle Size
Source. [4]


equipment.  Chemical extraction techniques may not
clean soil and tailings that contain a large quantity of
refractory minerals  [7-9].

Discussed in this chapter  are the  various  studies
needed  to  evaluate  the  technologies  for  their
applicability to site remediation.

9.3  Treatability Studies

When one or more remediation concepts are selected
that  appear applicable,  plans  may be  made for
bench-scale  laboratory studies.  Success there could
lead  to pilot-scale  testing  and eventually  to full-
                                                     71

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scale  demonstration of site cleanup.  This  step-wise
procedure  can  permit  stopping  or  redirecting
development  of  a  remediation technology that
appears unfruitful.  Carefully  developed work plans
and quality assurance plans must precede each step.

More  detailed information  about  the  selected
technologies would be developed at  the bench-scale
stage.  Examples  of  bench-scale studies required
include:

       For solidification or stabilization-selection and
       performance evaluation of solidifying  agents
       compatible  with the  chemical  composition of
       the specific waste group.
       For flotation-development of  surfactants  that
       enhance the  removal  of  the  contaminant in
       specific mineral form  while suppressing the
       other minerals in the specific waste group.
       For chemical extraction with inorganic salts -
       identification of specific inorganic  salts  and
       determination  of relevant process parameters
       to  effectively extract  the  radionuchde
       contaminant from the specific waste group.

Based on the information  developed in these studies,
detailed  remediation processes can be selected  that
may involve multiple  technologies.  Selection  of any
process must  include  consideration  of whether
appropriate  disposal methods are available for both
the concentrated fractions and the "clean" fractions.
Preliminary cost information  relative to each of these
processes  would  be  developed along  with
performance  expectations.  The  criteria  used  to
evaluate these  processes so that  some  processes
could  be selected for further  development could
include:

       Amount of expected waste volume reduction;
       Radioactivity  of  the  expected  "clean"
       fractions;
       Applicability to other waste groups;
       Technological uncertainty;
       Potential risks to remediation personnel;
       Potential to construct mobile  or transportable
       units;
       Generation  of any  toxic  by-products  or
       effluents;
       Potential to coremediate other hazardous
       chemicals in the specific waste group;
       Total cost of remediation; and
       Disposal site availability.

9.4 Pilot-Plant  Studies

After  all the  criteria listed above are  weighed
appropriately,  it is expected that no more than one or
two processes may qualify for pilot-scale  testing  for
a specific waste group.
The  pilot  testing  would be  used to develop  better
information  on the  performance  of the  process,
assessment of technical problems, and costs. Testing
must  be carried  out  over  a significant  duration to
obtain reliable data.

For  field  demonstration  and  full-scale  site
remediation,  the criteria applied earlier could be used
to select a remediation process.

9.5  References

1. U.S. Environmental Protection Agency. Technical
   Resource Documents on Hazardous Waste Land
   Disposal.  SW860  and SW870  Series. Office of
   Solid Waste, Washington DC. 1979-1987.

2. U.S. Environmental Protection Agency. Minimum
   Technology Guidance on Double Liner Systems.
   Draft. Office of Solid Waste. May 1985.

3. Council  on   Environmental  Quality.  Ocean
   Dumping  - A National  Policy.  A  Report  to the
   President. U.S. Government Printing Office. 1970.

4. U.S. Environmental Protection Agency. Guidance
   on  the  Preparation  of Feasibility Studies.
   Municipal Environmental  Research  Laboratory,
   Cincinnati  Ohio  Office of  Emergency and
   Remedial Response, Washington, D.C. 1983.

5. Olsson, R.K. Geological  Analysis of and Source
   of the Radium  Contamination  at  the Montclair,
   West  Orange,   and  Glen  Ridge  Radium
   Contaminated  Sites.  Department  of  Geological
   Sciences,  Rutgers University,  New  Brunswick,
   New Jersey, 1986.

6. Borrowman,  S.R., and  P.T.  Brooks.  Radium
   Removal from  Uranium  Ores and  Mill  Tailings.
   U.S. Bureau of Mines Report 8099, 1975.

7. Ryan,  R.K.,  and  D.M.  Levins.  Extraction  of
   Radium  from  Uranium Tailings.  CIM  Bulletin,
   October, 1980, pp. 126-133.

8. Yagnik, S.K.,  M.H.I.  Hurst,  and  S.  Seely. An
   Investigation of Radium Extraction from Uranium
   Mill  Tailings.  Hydrometallurgy, 7:61-75, 1981.

9. Ryon,  A.D.,  F.J.  Hurst,  and  F.G. Seely.  Nitric
   Acid Leaching  of  Radium and Other Significant
   Radionuclides from Uranium  Ores  and  Tailings.
   ORNL/TM-5944,   Oak  Ridge  National
   Laboratories, Oak Ridge, Tennessee, 1977.
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                                           Chapter 10
                                          Conclusions
This report provides a  technical  review of  the
technologies  that  may  be  useful in  removing
radionuclides  from  radiologically  contaminated
Superfund  sites. As a result  of this  review,  the
following conclusions have emerged:

10.1  Technological Approaches

       Alteration or  remediation  of  the radioactive
       decay  process,  thus changing  the
       fundamental hazard, is not possible.

       Remediation, to  date, has  only  involved
       removing  contaminated  material  and
       containing   it  in  above-ground  land
       encapsulation,  drums,  or  temporary storage
       sites. This approach has substantial technical
       backup.

       Alternative treatment technologies  that may
       warrant further  study  include  solidification,
       vitrification,  chemical   extraction,  physical
       separation,  and  combinations  of  physical
       separation and chemical  extraction. Even  if
       these treatment technologies were  effective,
       some form of final disposal would always be
       needed.

       Various remediation technologies  may have
       potential  to  reduce  the volume of  the
       contaminated waste  with  an  associated
       increase  in concentration  of the radioactive
       material.

       Remediation  technologies  generally result in
       the disturbance of contaminated material. The
       additional risk to  human health  and  the
       environment  must  be weighed against leaving
       the contaminated materials on-site in  a
       contained state, if that is an option.

       Physical separation and/or chemical  extraction
       technologies can  potentially  concentrate  the
       contamination, thereby  reducing  the volume
       and  weight  of the  waste material for final
       disposal.
       Remediation may include  soil  ventilation and
       shielding  around homes  to  protect people
       from radon and gamma radiation exposure.

       Ocean disposal  could  potentially be  a
       technically viable method.
10.2  Disposal
       All nonresidual waste must be disposed at a
       final site that is designed to meet security and
       longevity  criteria  appropriate  for  the
       concentration of radioactivity that is present.

       Capping  could  be  a more suitable method
       than  areal  removal  of radon  for  controlling
       radon emissions from large sources.
10.3  On-Site Treatment

       Solidification and vitrification technologies do
       not  reduce the  amount of the contaminated
       material. However,  they  may  immobilize  the
       contamination in the  waste material thereby
       increasing  the effectiveness and safety of the
       conventional  remediation   (e.g.,  land
       encapsulation).  Solidification  may  actually
       increase the volume  by the addition of  the
       solidifying materials.
10.4  Chemical Extraction Technology

       Several chemical  extraction  technologies
       have  been  studied  in  the laboratory by
       various investigators.  These include  the use
       of  salt solutions, mineral acids, and various
       complexing  agents  to extract the radioactive
       contaminants from the soil.  Several of  these
       experiments  had  relatively high  extraction
       efficiencies. For example, up  to  97  percent
       radium and 99 percent thorium were removed
       using  nitric acid and up to 92  percent  of
       radium was removed   from  uranium mill
       tailings using EDTA.
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       Chemical  extraction  technologies potentially
       applicable for  treating radioactive wastes  at
       Superfund  sites  are being  researched  and
       investigated. Significant development work  at
       bench  and  pilot  scale  would  be  required
       before these technologies could be utilized  at
       full scale.

10.5  Physical Separation and Reduction

       Physical separation technologies can only be
       useful for  those waste materials in which the
       radioactive contamination  resides in  a certain
       particle size fraction. This  information about
       the waste materials at the 20 Superfund sites
       is not presently available in sufficient detail.
       Extensive  soil  characterization  is  required  at
       these Superfund  sites to  better establish the
       applicability  of  the  physical  separation
       technologies.

       The physical separation technologies  are at a
       mature stage  of development.  A significant
       selection   and variety  of hardware  are
       available  in the  uranium  mining  industry.  If
       detailed   soil  characteristics   at  the
       radiologically contaminated  Superfund  sites
       are developed, it could  be possible to design
       specific systems  for further bench-scale and
       pilot-scale testing  and evaluation.

10.6  Combined Physical Separation and
      Chemical Extraction

       At a specific  site,  using  a combination of
       physical separation  and chemical extraction
       technologies is likely  to  be more  effective
       than  using  either type   of  technology
       separately.

10.7  General  Issues

       It is  important to note that in  some cases
       there  may be two  categories  of  residual
       contamination: process  wastes  and  soils
       contaminated with  isolated radionuclides or
       groups of  radionuclides. While removal of the
       radioactive fractions  of  soils  contaminated
       only  with  single  radionuclides such  as
       uranium or plutonium might result in  "clean"
       fractions acceptable for unrestricted  disposal,
       removal of the radioactivity from  a  soil  also
       contaminated with  process  wastes may  not.
       In  the second  case  the nonradioactive
       fractions  of the residues could result in an
       unacceptable  product.  Therefore,  before
       considering  any  separation  technique, it  is
       necessary that acceptable limits for  both the
       radiological contaminants and  the  non-
       radiological contaminants be defined.  In some
       cases,  multiple  treatments  or combined
       technologies  could  be  required to  achieve
       environmental goals.

       Every  site remediation  involving radioactive
       materials must involve a final, environmentally
       safe  disposal  site  for  the  radioactive
       materials.

       Even if it proves feasible at a particular site to
       lower the concentration of radionuclides in the
       soil by  physical separation and/or  chemical
       extraction  to  some acceptable level,  the
       "clean" fractions are likely to  contain traces
       of  radionuclides.  Therefore,  adequate
       attention  must be  given  to  whether  the
       "clean" fractions  may  be  returned to  the
       original  site or an  unrestricted location  or
       must be sent  to a disposal  site.

       When developing technologies for cleanup at
       a  site,  it  is  essential  that  a step-wise
       procedure be  used. This  should begin  with
       assessment  studies  and  bench-scale
       testing,  followed by pilot-scale testing.  Only
       if  these are  successful  should  full-scale
       demonstrations be attempted. Carefully
       developed work plans and  quality assurance
       plans should precede each step.

10.8  Site Characteristics

       Twenty  Superfund sites  have  radiologically
       contaminated  soil spread over 9500 acres. Of
       these  sites, five are DOE  sites (3  FUSRAP
       and 2  SFMP). [Data  presented  here  are
       accurate as of December 1987.]

       Any choice of  remediation  technologies for
       radioactive  waste  at Superfund sites would
       have to be site specific.  Extensive site  soil
       characterization studies, such  as  complete
       mineral  analysis,  particle   size  distribution,
       radionuclide-contaminated  distribution,  soil
       texture,  and permeability,  would be required
       prior to  development and application  of most
       of the technologies,  land encapsulation being
       an exception.
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                                           Appendix A
                        Applicable  Laws, Regulations, and Guidance
 This  appendix  briefly presents  some of the laws,
regulations,  and  guidance that  are part  of  the
framework within which technologies may be selected
for remediation of Superfund sites.  This report does
not attempt nor is it intended to provide a complete or
detailed analysis of how various laws, regulations, and
guidance apply in  general or at a specific  Superfund
site, nor is it intended to set or interpret policy for the
selection  or  use  of  technologies  to  clean  up any
Superfund or other hazardous waste site.

Superfund sites are  remediated under the provisions
of the Comprehensive  Environmental  Response,
Compensation, and Liability Act of 1980 (CERCLA) as
amended by  the  Superfund  Amendments  and
Reauthonzation Act of 1986 (SARA). Several sections
of CERCLA and SARA are pertinent to the intent of
this document.

EPA undertakes remedial  investigation and feasibility
studies (RI/FS) at  National Priorities List (NPL) sites
where there is a release of a hazardous substance or
pollutant  or  contaminant,  or threat of release,  to
identify those releases and their nature,  along with
planning  and  investigations necessary  to  direct
response actions.  Radiologically contaminated sites
have qualified for the NPL.

Section 311 of CERCLA, commonly referred to as the
Superfund Innovative Technology  Evaluation  (SITE)
program,  provides for demonstrations  of  alternative
technologies  in  the cleanup of  sites on  the NPL.
Radiologically  contaminated sites and   treatment
technologies,  such  as  those  described  in  this
document, may  qualify for demonstration under this
program.  The SITE program generally  requires that a
technology developer bear the cost of demonstrating
his  technology,  while EPA bears  the  cost  of  its
evaluation. Proof of  concept laboratory results must
be supplied by the technology developer before EPA
can consider funding a  demonstration  under this
program.

SARA  Section  1l8(m)  (not  an  amendment  to
CERCLA) states that it is the sense of Congress that
fully  demonstrated remediation  methods,  such  as
off-site transport and disposal,  are not  necessarily
required at sites on the NPL because of the presence
of radon. This  section  states  that  innovative or
alternative methods that  protect  human health  in a
more cost effective manner may be used.

SARA  Section  121  (Cleanup  Standards) states a
strong  statutory  preference  for  remedies that are
highly  reliable and  provide long-term  protection. In
addition to the requirement for remedies  to be  both
protective of human health and the environment and
cost-effective,  additional  remedy   selection
considerations in 121 (b) include:

  A preference for  remedial actions that  employ
   treatment  that  permanently  and  significantly
   reduces  the  volume, toxicity,  or mobility of
   hazardous  substances,  pollutants,   and
   contaminants as its principal element.

  Offsite transport and disposal  without treatment is
   the  least favored alternative  where practicable
   treatment technologies are available.

  The  need to  assess the  use of  permanent
   solutions  and alternative treatment technologies
   or resource recovery  technologies  and use  them
   to the maximum extent practicable.

Section 121(d)(2)(A) of SARA incorporates into law
the CERCLA Compliance  Policy, which specifies that
Superfund  remedial actions  meet  any  Federal
Standard requirements, criteria, or limitations that are
legally  applicable  or relevant  and  appropriate
requirements  (ARARs) under any  Federal or  state
environmental law.

CERCLA Section 104(a)(3) limits Federal response
authority for  releases  of  naturally  occurring
substances in locations  where  they  are naturally
found. However, this section does not apply for many
of the radiologically contaminated Superfund sites.

The   Low-Level   Radioactive  Waste   Policy
Amendments Act of 1985  (LLRWPAA) requires states
and  compacts to develop siting  plans for low-level
radioactive waste (LLW) disposal facilities by January
1, 1988.  These  disposal  facilities  may  receive
commercial  mixed  low-level  radioactive   and
hazardous waste (Mixed LLW), which is regulated by
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the U.S.  Nuclear  Regulatory Commission  (NRC)
under the Atomic Energy Act (AEA) as amended, and
by the EPA under the Resource Conservation  and
Recovery  Act  of 1976 (RCRA),  as  amended.  NRC
has  promulgated LLW  regulations and EPA  has
issued  guidance  that  pertains  to   the  siting
requirements for disposal facilities for Mixed LLW.

Section  5(e)(1)(B) of the LLRWPAA requires states
and  compacts to  develop  siting  plans for  LLW
disposal facilities by January 1,  1988.  In  addition to
other  information, these siting plans must identify, to
the extent practicable, the  process for (1) screening
for broad  siting areas, (2)  identifying and evaluating
specific  candidate sites, and (3) characterizing the
preferred site(s). It is anticipated that this  process will
be based primarily on the site suitability requirements
that apply to  LLW disposal.  If facilities also receive
Mixed LLW, their  siting requirements  will  reflect
additional  requirements  that  apply  to  disposal  of
hazardous waste as defined by RCRA.

Combined NRC-EPA Siting Guidelines for Disposal
of Commercial  Mixed Low-Level Radioactive and
Hazardous Waste (see Addendum) provide guidance
to facilitate development of siting plans for disposal
facilities that may receive Mixed LLW.

Joint  NRC-EPA Guidance  as a  Conceptual  Design
Approach  for Commercial Mixed   Low-Level
Radioactive and Hazardous Waste Disposal Facilities
(see  Addendum)  presents  a conceptual  design
approach that  meets the regulatory  requirements of
both  agencies  for the safe  disposal of Mixed LLW.
Other designs, or variations on the  proposed  design
concept,  may also  be  acceptable   under  the
requirements of both agencies and  will be reviewed
on a  case-by-case basis as received.

Standards  developed under Section 275  of  the
Atomic Energy Act  and Section  206 of the Uranium
Mill Tailings Radiation Control Act of 1978 may  be
applicable  or  relevant  and  appropriate   on  a site
specific   basis  to  the  cleanup  of radiologically
contaminated  Superfund  sites. In January 1983, the
EPA  promulgated   40 CFR  192,  Health  and
Environmental Protection Standards  for Uranium and
Thorium Mill Tailings under authority of  these Acts.
The  pertinent  standards are  contained  in 40  CFR
192.12,  192.32, and 192.41, and deal with  the
acceptable levels of  radioactivity  in residual materials
and radiation  emission levels from  them, and  with
disposal  requirements.  The  disposal  requirements
include a  design  life of at  least  200  years  and
preferably  1,000 years where reasonably achievable.

The Department of Energy (Office of  Nuclear Energy)
operates  four  remedial  action  projects  for
radiologically contaminated  sites  that parallel EPA's
Superfund  program.  Remedial actions  have  been
completed  or  are in  advanced  stages  at  some of
these sites. These DOE projects are as follows:

1.  Formerly  Utilized  Sites Remedial Action  Project
    (FUSRAP) under authority of the Department of
    Energy Organization Act of 1977.

2.  The Uranium Mill Tailings Remedial Action  Project
    (UMTRAP)  under  authority  of  Public  Law  95-
    604,  the  Uranium  Mill Tailings Control  Act of
    1978.

3.  The Grand Junction  Remedial  Action Project
    (GJRAP)  under  Public  Law  92-314  (1972)
    amended  by Public Law  95-236 (1978).

 4.  The Surplus  Facilities  Management  Program
    (SFMP) under authority  of  the  Department of
    Energy Organization Act of 1977.

These projects are described in Appendix B.

In addition,  DOE's  Office of  Defense  Waste  and
Transportation  Management  (DWTM) is  responsible
for  safely  managing defense  waste as  generated,
transporting it,  and storing it,  and is also  responsible
for  developing and implementing  the  technology
needed  for long-term management  and  eventual
disposal of the waste.

One of the options  for radioactive waste  disposal is
ocean  disposal. Ocean  disposal  is controlled by
regulations  under the  Marine  Protection, Research,
and  Sanctuaries  Act  of  1972,  as amended.  The
regulations are  contained in 40 CFR  Parts  220
through 229 and are currently being revised. Perhaps
the  most pertinent are found in 40 CFR 227, Criteria
for  the Evaluation of  Permit Applications for  Ocean
Dumping of Materials. A unique provision of the Act is
that a permit  may not be issued by EPA for ocean
disposal of  radioactive materials without the approval
of both Houses of Congress. The Act prohibits ocean
disposal of high level  wastes;  only low level  wastes
are  eligible to be considered for a permit.

Although this document has been specifically directed
at the remediation of  Superfund  sites,  it may have
applicability to  permitted sites that require corrective
actions under RCRA as  amended by the Hazardous
and Solid  Waste  Amendments of  1984 (HSWA). A
RCRA site can be placed on  the  CERCLA NPL if the
operator is  bankrupt, unwilling to  carry out corrective
action, or  has  lost his authorization to  operate  (see
Preamble to 40 CFR Part 300, June 10, 1986).
                                                76

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 Addendum 1 - Combined NRC-EPA
 Siting Guidelines for Disposal of
 Commercial Mixed Low-Level
 Radioactive and Hazardous Wastes

 Introduction

 The  Low-Level  Radioactive  Waste  Policy
 Amendments Act of 1985 (LLRWPAA) requires states
 and  compacts  to develop siting  plans  for  low-level
 radioactive waste  (LLW) disposal facilities by January
 1,  1988.  These  disposal facilities may receive
 commercial  mixed  low-level  radioactive and
 hazardous waste (Mixed LLW), which is regulated by
 the U. S.  Nuclear Regulatory Commission (NRC) the
 Atomic Energy Act (AEA), as amended, and by the U.
 S. Environmental  Protection Agency (EPA)  under the
 Resource  Conservation  and  Recovery Act  (RCRA),
 as amended.  Mixed  LLW is  defined as waste  that
 satisfies the definition of  LLW in  the LLRWPAA and
 contains  hazardous  waste  that  either   is  listed in
 Subpart D of 40 CFR Part 261 or causes the LLW to
 exhibit any  of  the  hazardous  waste characteristics
 identified in Subpart C of 40 CFR Part 261.  To assist
 in applying  that definition,  NRC and  EPA recently
 developed joint guidance entitled "Guidance on the
 Definition  and  Identification  of  Commercial  Mixed
 Low-Level  Radioactive and Hazardous  Waste  and
 Answers  to Anticipated  Questions"  (Jan.  8,  1987).
 NRC has promulgated LLW regulations and EPA has
 promulgated hazardous waste  regulations that pertain
 to the siting requirements for disposal  facilities for
 Mixed LLW. Because of uncertainty  about the precise
 content of EPA's future location standards, states and
 compacts  may have  questions  regarding  the  site
 selection process. This document provides combined
 NRC-EPA  siting guidelines, to  be  used before  EPA's
 new  location  standards are promulgated, to facilitate
 development of siting plans for disposal  facilities that
 may receive Mixed LLW.

 Section 5(e)(1)(B) of the LLRWPAA requires  states
 and  compacts to develop siting  plans  for  LLW
 disposal facilities by January 1,  1988. In addition to
 other information,  these siting  plans must identify, to
 the extent practicable the process  for (1) screening
 for broad siting areas,  (2) identifying and evaluating
 specific candidate sites, and  (3) characterizing  the
 preferred site(s). It is  anticipated that this  process will
 be based primarily on the site suitability requirements
 that apply  to LLW disposal. If facilities  also receive
 Mixed  LLW,  their siting requirements  will  reflect
 additional  requirements  that  apply  to  disposal  of
 hazardous  waste as defined by RCRA.

 In  1982, NRC promulgated regulations which contain
minirnum  site suitability  requirements for LLW land
disposal facilities in  10  CFR  61.50. EPA  has also
promulgated  minimum  location   standards  for
hazardous  waste  treatment,  storage and  disposal
 facilities in 40  CFR  264.18. Considerations  affecting
 siting are also found in 40 CFR 270.3, 270.14(b) and
 (c).  Although both NRC  and EPA have incorporated
 siting  requirements  in existing regulations  for  LLW
 and hazardous  waste disposal, respectively, the  1984
 Hazardous and Solid Waste  Amendments (HSWA) to
 RCRA  require  EPA to  publish  guidance identifying
 areas of vulnerable hydrogeology. In July 1986, EPA
 published this  guidance  in  "Criteria  for  Identifying
 Areas  of Vulnerable  Hydrogeology  under  the
 Resource Conservation   and  Recovery  Act  -
 Statutory Interpretative Guidance, July 1986, Interim
 Final  (PB-86-224953)." The  1984  HSWA  also
 requires (in  Section  3004(o)(7))  that  EPA specify
 criteria for the acceptable location  of new and existing
 hazardous waste  treatment, storage,  and  disposal
 facilities.  EPA  anticipates proposing these  location
 standards in September 1987 and promulgating  them
 in final form by  September 1988.

 EPA's  scheduled date  for promulgating  its  final
 location standards is  nine months after the LLRWPAA
 January  1, 1988, milestone  for non-sited states and
 compacts to  develop siting  plans. Therefore, states
 and  compacts may require some assistance in  their
 efforts to develop siting plans  for  LLW disposal
 facilities  that  may receive  Mixed LLW. The two
 agencies  are issuing these  combined  guidelines  to
 promote the  development of siting plans by states
 and  compacts.  Both  NRC and  EPA consider that the
 absence  of  EPA's  final comprehensive  location
 standards for hazardous waste disposal facilities  is an
 adequate basis  for  states  and compacts to delay
 development of siting plans for LLW disposal.

 States and compacts should proceed at this time  to
 develop siting plans  in accordance  with the  existing
 NRC and EPA requirements. The  following combined
 NRC-EPA guidelines  are  provided  for use  by the
 states and compacts, and are based on existing  NRC
 regulations in 10 CFR Part 61 and EPA regulations in
 4  CFR  Parts 264 and 270. As  EPA  continues its
 development of location standards, both agencies will
 strive to keep states  and compacts  informed about
 the status of the developing siting requirements.


 Combined NRC-EPA Siting Guidelines

 Site  suitability requirements for land  disposal  of  LLW
 are  provided  in  10  CRF   Section  61.50.  These
 requirements  constitute  minimum  technical  require-
 ments  for  geologic,  hydrologic,  and demographic
 characteristics of  LLW disposal  sites.  Several of
 these   requirements  identify   favorable   site
 characteristic  for  near-surface  disposal facilities for
 LLW. The majority of the site suitability requirements,
 however,  identify  potentially  adverse   site
 characteristics that  must not  be  present  at  LLW
disposal sites. The site suitability requirements in 10
 CFR Part 61 are intended to  function collectively  with
the requirements for facility design  and operation, site
                                                77

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closure, waste classification  and segregation,  waste
form and  packaging,  and  institutional  controls  to
assure isolation  of LLW for the  duration  of  the
radiological hazard. The  NRC  Technical Position
entitled  "Site   Suitability,  Selection,  and
Characterization"  (NUREG-0902) provides detailed
guidance  on  implementing  the  site  suitability
requirements in 10  CFR Part 61.

EPA has also  promulgated certain  minimum location
standards  for  hazardous waste  treatment, storage,
and disposal facilities.  These  standards are provided
in  40 CFR Section 264.18. As previously  noted, the
hazardous waste  regulations  also include  other
location  considerations  as  well  as  applicable
provisions of  other Federal   statutes. For  example,
Subpart F of 40 CFR Part 264 requires establishment
of  ground-water  monitoring  programs capable  of
detecting  contamination  from land  disposal  units.
While not a siting criterion per  se this requirement
can  preclude  siting  in  locations  that  cannot  be
adequately monitored  or characterized.  A  further
description  of  location-related   standards and
applicable provisions of other  Federal statutes  can be
found in  the "Permit  Writers" Guidance  Manual  for
Hazardous  Waste Land  Storage and  Disposal
Facilities:  Phase I  Criteria for Location Acceptability
and  Existing  Applicable  Regulations" (Final  Draft  -
February 1985). This guidance manual describes five
criteria for determining location acceptability; ability to
characterize, exclusion of high  hazard  and unstable
terrain, ability to monitor, exclusion of protected lands,
and identification of areas of vulnerable hydrogeology.
The first four  of  these  criteria  have a basis  in the
regulations and are fully  described in the manual. The
fifth  criterion,  vulnerable  hydrogeology, is defined in
the  RCRA interpretive  guidance manual  mentioned
above  (Criteria for Identifying Areas of  Vulnerable
Hydrogeology  under the  Resource Conservation and
Recovery  Act-Statutory  Interpretive Guidance, July
1986,  Interim  Final (PB-86-224953)).

However,  since HSWA also added other requirements
in  addition to location standards to prevent or mitigate
ground-water  contamination, EPA recognizes  that
vulnerable hydrogeology must be considered in
conjunction  with  design and  operating  practices.
Vulnerability should not  be the  sole determining fact
in   RCRA  siting  decisions.  Rather, this criterion
provides a trigger for more detailed evaluation of sites
that are identified as having potentially  vulnerable
hydrogeology.  The extent of necessary  site  review
and evaluation is related directly  to the  extent to
which  a location "fails"  or "passes" the  vulnerability
criterion.  Sites that are  determined to be  extremely
vulnerable will require much  closer examination than
sites that are  deemed non-vulnerable. The results of
this more detailed review may then provide  a basis
for  eventual permit  conditions  or modifications  in
design or operating practices.
By  combining  the above technical requirements,
standards, and  guidance of both agencies, NRC and
EPA have  formulated  the eleven  guidelines listed
below.  The  use  of  terms  in the guidelines  is
consistent with  their regulatory definition  in 10 CFR
Part 61  and  40  CFR  Parts  260  and  264.  The
combined set of location guidelines is intended by the
agencies to apply only as  guidance to  states  and
compacts developing  siting  plans  for  LLW disposal
facilities that  may receive   Mixed  LLW.  These
combined guidelines are  not   intended to  displace
existing standards  and guidance.  In  addition,   the
independent guidance  of both agencies  should be
considered  in any  application of the combined siting
guidelines.

The combined   siting   guidelines  for a commercial
Mixed LLW disposal facility are as follows:

I. Primary emphasis in  disposal site  suitability should
be  given to isolation of wastes and to disposal  site
features that ensure that  the long-term performance
objectives of 10 CFR Part  61, Subpart C are met.

2.  The disposal  site   shall  be  capable of being
characterized,  modeled, analyzed,  and monitored. At
a minimum, site characterization must be  able to (a)
delineate  ground-water flow   paths,  (b)  estimate
ground-water  flow velocities,  and  (c)  determine
geotechnical properties sufficiently to support facility
design.  At a   minimum for  site  ground-water
monitoring disposal site operators must be able to (a)
assess the rate and direction of ground-water flow in
the  uppermost  aquifer,  (b) determine background
ground-water  quality,  and  (c)  promptly  detect
ground-water contamination.

3. The  disposal site must be  generally well-drained
(with respect to surface water) and free  of areas of
flooding or frequent ponding.

4.  The disposal site   shall  not be  in  the  100-year
floodplam.

5.  The  site must be located  so  that  upstream
drainage areas  are minimized to decrease  the amount
of runoff that could erode or inundate waste disposal
units.

6.  Disposal sites  may  not  be  located on  lands
specified in  10 CFR  Section  61.50(a)(5),  including
wetlands (Clean Water Act) and coastal high hazard
areas  (Coastal  Zone  Management Act).  Location of
facilities on the following lands must be consistent
with  requirements  of  applicable  Federal  statutes:
archeological  and  historic places  (National Historic
Places Act);   endangered  or  threatened habrnU
(Endangered   Species  Act);  national  parks,
monuments, and  scenic rivers  (Wild and  Scer,,c
Rivers Act); wilderness areas (Wilderness Protection
                                                  78

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Act);  and wildlife  refuges  (National  Wildlife  Refuge
System Administration Act).

7.  The  disposal  site  should  provide  a  stable
foundation for engineered containment structures.

8. Disposal sites must not be located in areas where:

(a) tectonic processes  such  as faulting, folding,
seismic activity, or vulcanism  may occur with  such
frequency and extent  to affect significantly the ability
of the disposal facility to  satisfy the  performance
objectives specified in Subpart C of 10 CFR Part  61,
or may preclude defensible modeling and  prediction
of long-term  impacts; in  particular,  sites  must  be
located more than 200 feet  from a fault that has been
active during the Holocene Epoch;

(b) surface geologic processes  such as  mass
wasting, erosion, slumping,  landsliding, or weathering
occur  with such  frequency and extent  to  affect
significantly the ability of  the disposal  facility to  meet
the performance objectives in Subpart C of 10 CFR
Part 61,  or  may preclude  defensible  modeling  and
prediction of long-term impacts;

(c) natural  resources exist that,  if exploited,  would
result in failure to meet the  performance objectives in
Subpart C of 10 CFR Part 61;
(d)  projected  population  growth  and  future
developments within  the  region or  state where the
facility is to be located are likely to affect the ability of
the  disposal  facility  to meet  the  performance
objectives in Subpart C of 10 CFR  Part 61; and

(e) nearby  facilities  or  activities could  adversely
impact  the  disposal  facility's  ability to satisfy  the
performance objectives in Subpart C  of 10 CFR Part
61  or could significantly mask  an  environmental
monitoring program.

9. The  hydrogeologic unit beneath the site shall not
discharge ground water to the land surface within the
disposal site boundaries.

10. The water  table  must be  sufficiently below the
disposal facility  to prevent  ground-water  intrusion
into the waste,  with the exception outlined under 10
CFR Section 61.50(a)(7).

11. In   general,   areas  with  highly  vulnerable
hydrogeology deserve special  attention in  the siting
process. Hydrogeology is considered vulnerable when
ground-water travel time  along any  100-foot  flow
path from the edge of the  engineered  containment
structure  is  less  than  approximately 100  years
(Criteria  for  Identifying  Areas  of  Vulnerable
Hydrogeology  Under  RCRA-Statutory Interpretive
Guidance,  July  1986,  Interim  Final   (PB-86-
224953)).  Disposal  sites   located  in areas of
vulnerable hydrogeology may require  extensive,  site-
specific  investigations which  could  lead to  and
provide  bases  for  restrictions or  modifications to
design or operating practices. However, a finding that
a site is located in an area of vulnerable hydrogeology
alone, based on the EPA criteria,  is  not considered
sufficient to prohibit siting under RCRA.
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Addendum   II   -   Joint  NRC-EPA
Guidance   on  a  Conceptual   Design
Approach  for  Commercial  Mixed  Low-
Level Radioactive  and Hazardous Waste
Disposal  Facilities

Introduction
The  Low-Level  Radioactive  Waste  Policy
Amendments  Act  of 1985  (LLRWPAA) requires that
the three  operating low-level  radioactive  waste
(LLW)  disposal facilities  remain available through
1992. By that time, all  states and compact regions
are required  to assume complete responsibility for
LLW  disposal. Both existing  and  new  disposal
facilities may  receive  commercial  mixed  low-level
radioactive and hazardous waste (Mixed LLW),  which
is regulated  by  the  U.S.  Nuclear  Regulatory
Commission (NRC) under the  Atomic  Energy  Act
(AEA), and by the U.S.  Environmental  Protection
Agency (EPA) under the Resource Conservation  and
Recovery Act (RCRA).  Mixed  LLW  is defined as
waste  that  satisfies the  definition of LLW  in  the
LLRWPAA and contains hazardous waste  that either
(1) is listed  as a hazardous waste in Subpart D of 40
CFR Part 261 or  (2) causes the LLW to exhibit any of
the hazardous waste  characteristics identified in
Subpart C of  40  CFR Part 261.  To assist  in applying
this definition, NRC and  EPA issued joint guidance
entitled "Guidance on the Definition and Identification
of Commercial Mixed  Low-Level Radioactive Waste
and Answers  to Anticipated Questions" on  January 8,
1987.

This jointly  developed  NRC-EPA guidance document
presents a conceptual  design  approach  that  meets
the regulatory requirements of both agencies for the
safe  disposal of  Mixed  LLW. Other  designs, or
variation of the proposed design  concept may also be
acceptable  under the requirements of both agencies
and will  be  reviewed  on  a case-by-case basis as
received.

EPA  regulations  in 40  CFR  Part 264, Standards for
Owners and Operators  of  Hazardous  Waste
Treatment,  Storage, and Disposal Facilities,  identify
the design and  operating  requirements  for  owners
and operators that dispose of  hazardous waste  in
landfills  [264.300  to  264.317]. These   regulations
involve requirements for the installation  of  two or
 more  liners  and  a leachate collection  and removal
 system (LCRS)  above  and between  the liners to
 promote  human  health  and the  environment.
 Exceptions to the double liner and leachate collection
 system requirements are allowed, if alternative design
 and  operating  practices,  together with  location
 characteristics, are demonstrated to EPA  Regional
 Administrator to  be equally effective in preventing the
 migration  of any hazardous  constituent  into the
 ground water or  surface water.
NRC  regulations in 10  CFR  Part  61,  Licensing
Requirements for Land  Disposal Radioactive Waste,
indicate that long-term stability of the waste and the
disposal site require minimization of access  of water
to  the  waste [61.7(b)(2)]  and that the  disposal  site
must  be  designed to  minimize,  to the extent
practicable, the contact of water with waste during
storage, the contact of standing  water with  waste
during  disposal,  and the  contact  of percolating
standing   water  with  wastes  after  disposal
[61.51(a)(6)j. The primary  objective  of the above
NRC regulations is to preclude the possibility of the
development  of  a  "bath-tub"  effect  in which  the
waste could become immersed in liquid (e.g.,  from
infiltration  of surface water  runoff) within  a  disposal
unit  below grade  with  a low-permeability  bottom
surface.

The guidance on a  conceptual design approach  that
is offered in the subsequent paragraphs is intended to
present basic design concepts that are acceptable in
addressing the regulations of both the NRC and EPA
with  respect to  requirements  for liners,  leachate
collection systems and efforts  to minimize the contact
of liquid with the waste. It should be  recognized  that
the guidance is being provided at the conceptual level
and   that  the   design  and  details  that  are
complementary  to specific site conditions need to be
engineered  by  potential  waste  facility  owners  and
operators.  The  application  of the  guidance in  this
document  will  not affect  the requirements for
licensees of waste disposal facilities to comply with all
applicable NRC and EPA regulations.


Conceptual Design
Sketches  and   a  brief  discussion   of the design
considerations for an above grade disposal unit are
provided.  This  design concept  has  been developed
primarily to demonstrate the  integration of  EPA's
regulatory requirements for two or more liners and  a
leachate collection system above and between liners
and  the regulations of  the   NRC  that  require the
contact of water with  the  waste be minimized.  In
addition, the design concept  fulfills  the need under
both  agencies'  regulations  to assure  long-term
stability and  minimize active  maintenance  after site
closure.

In this approach, the Mixed  LLW would be  placed
above the original ground surface in a tumulus that
would be blended into the  disposal site topography.
Schematic details  of some of the  principal  design
features of an above grade Mixed LLW disposal unit
are  provided  in the sketches  accompanying  this
guidance  document. Figure  A1 depicts the  three
 dimensional overall  view of  a  concept Mixed  LLW
 disposal  unit;   Figure  A2  provides details of  the
 perimeter berm,  liners,  and  leachate collection
 system; Figure  A3  presents  a cross-sectional  view
                                                 80

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of the covered portion of the disposal unit; and  Figure
A4 describes the final cover system.

In the overall view of the  Mixed LLW disposal facility,
the  double  liners  leachate  collection  and  removal
system are  installed  before  the  emplacement  of the
Mixed LLW; and  the cover system  is  added  at
closure.  The  leak  detection tank  and   leachate
              collection tank are encircled by  a berm that controls
              surface water runoff from  precipitation that would  fall
              directly on the waste facility site. The drainage pipes
              in  the  upper primary collection system would collect
              any  leachate  that  could possibly develop above the
              top flexible  membrane liner and below the emplaced
              waste.  Any leachate collected  would  drain through
              pipes to the  primary leachate  collection  tank where
 Figure A1.    Mixed waste disposal facility.
                                                                          Final Cover
                                                                                      Double Liner & Leachate

                                                                                     Collection & Removal System
                                                                                         Leachate       (LCRS)
                                                                                           Collection Pipes
                                                  Leachate Collection Manifold

                                            Leachate Collection Tank
                              Leak Detection Tank
 Figure A 2.    Double liner and leachate collection system.
                                                                             Separation to Assure
                                                                             Leachate Flow into LCRS
                             Solidified Waste

                                          Bottom of Waste .7
           Primary LCRS

         Top Liner (Flexible Membrane Lmer-FML)
                                       Perimeter Berm for
                                       Leachate Runoff Control
           -  Leachate Detection, Collection
              and Removal System
                   Bottom Liner (Composite-
                   FML & Compacted Clay*
 j/-o- o'.: 
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the leachate would be tested and treated, if required.
Any leachate  collected  by  the  lower  leachate
collection and removal system would dram to the leak
detection  tank.  The  development  of  significant
amounts of  leachate from the  solidified waste  after
closure  is not anticipated. This is because the closure
requirements provide  that  the  cover  must be
designed and constructed  1)  to provide  long-term
minimization of water infiltration  into  the closed
disposal facility,  2)  to  function  with  minimum
maintenance, 3) to promote drainage and  minimize
erosion, and 4) to have a permeability less than or
equal to the permeability of any bottom liner system.
It  is anticipated  that the  area  shown on  Figure A3
between the slope of the final  cover  and the run-on
control berm, where  the tanks  are located,  would be
regraded and the  tanks removed at  the  end of the
post-closure care  period  (normally  30 years)  when
leachate development  and collection  is  no longer  a
problem.

Figure A2 provides  the general  details  required by
EPA  regulations for the  double liner and leachate
collection and removal  system. The  perimeter berm
for leachate runoff  control  would  assure  that all
leachate is  collected  below the waste  and safely
contained and transported through the drainage layers
and pipes to the tanks  located  outside the final cover
slope. NRC's regulation requiring minimizing contact
of the waste with  water are  fulfilled by requiring the
waste to be placed  above the level  of the highest
water table fluctuation  and above the drainage layers
where ieachate would collect. The bottom elevation of
the solidified Mixed  LLW would be   required  in all

Figure A3.     Cross-sectional view A-A
             (vertical scale exaggerated).
instances to  be at elevations above the top of the
perimeter berm.

In  Figures A3 and A4, the design concepts  for the
final  cover over  the  solidified waste  zone and the
perimeter berm  are presented.  The actual zone  for
placement of  solidified Mixed  LLW may  consist of
different  options,  depending  on  the  licensee's
selection. Options that would be  acceptable  include
use of stable  high integrity waste containers (HICs)
that have the spaces  between containers  filled with a
cohesionless,  low  compressible  fill material  or
placement of the  waste in  an engineered  structure,
such as  a reinforced  concrete vault. A cover  system
over the waste that would  be acceptable  to the EPA
and NRC is shown in Figure A4.  The  cover  system
would consist of (1) an outer rock or vegetative layer
to  minimize erosion and  provide  for  long-term
stability,  (2) a filter and drainage layer  that transmits
infiltrating water  off of the underlying low permeability
layers,  (3) an  impervious  flexible  membrane  liner
overlying  a compacted low permeability  clay layer,
and  (4)  a filter and drainage  layer beneath the
compacted clay  layer. If the  solidified waste  zone
does not consist of an engineered  vault structure with
a top roof, an additional compacted  clay layer should
be placed  immediately above the  emplaced waste to
direct any water infiltration away from the waste zone.
Mixed  LLW  that contains Class  C  waste  as
designated  by   NRC's regulations  would need  to
provide sufficient thickness of cover materials or  an
engineered intruder  barrier  to  ensure the required
protection against inadvertent intrusion.
                   Area Regraded Following
                   Post-Closure Care Period
                                                                              Final Cover
                                                                              (See Fig A4)
                                              & Leachate Collection System

                                                  rm
                                                                                       Perimeter
                                                                                         Berm for
                                                                                         Leachate
                                                                                         Run-off
                                                                                         Control
                 Leak Detection Tank
                 (To EPA Standards)
                                                              Unsaturated Soil
                                     Run-on
                                  Control Berm
                                                                             JL
                                                                                 Ground water
                                                   82

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Figure A4.    Waste cover system
             (vertical scale exaggerated).
                                                                                             FML
                             Slope Designed for
                             Long-term Stability

                             Filter & Drainage
                                 Layer

                        Rock or Vegetative Cover
           Pipes Cutoff at Slope Following
           Post-Closure Care Period
                                 Backfill  -
                                 Compacted Clay  
                                                                    Filter & Drainage
                                                                    Layer
                                                                                 Double Liner & Leachate
                                                                                 Collection System
                                                                                  Perimeter Berm for
                                                                                  Leachate Control
         Surface Drainage Channel
     Primary LCRS Collection Pipe ,
   Leachate Detection Pipe \    \
                                                                                  Separation to Assure
                                                                                  Leachate Flow into LCRS
Variations on  the  above described  design approach
may include  placement of  the  Mixed LLW in an
engineered  reinforced concrete  vault, a  steel  fiber
polymer-impregnated  concrete  vault, or  double-
lined high  integrity containers that are hermetically
sealed.  If  proposed  by  license applicants, these
variations would be reviewed by both the EPA and
NRC  on  a case-by-case  basis to  evaluate  their
acceptability  and  conformance with  established
federal regulations.

For questions  related to  NRC regulations and design
requirements,  contact:

    Dr. Sher Bahadur, Project Manager
    Division of Low-Level Waste  Management and
       Decommissioning
    Mail  Stop 623-SS
    U.S.  Nuclear Regulatory Commission
    Washington, DC 20555
Facility  specific questions, permitting  requirements,
variances and other  related  concerns  should be
addressed to  either the EPA regional office or state
agency  authorized to  administer the  mixed  waste
program as appropriate. For general  questions  related
to EPA regulations and design requirements, contact:

    Mr.  Kenneth Skahn, Senior Engineer
    Waste Management Division
    Mail  Stop  WH-565E
    U.S. Environmental  Protection Agency
    401  M Street, SW
    Washington, DC 20460
                                                   83

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                                           Appendix B
               Characteristics of Man-Made Radiologically Contaminated Sites
Introduction

The  type  of remediation  that may  be reasonably
applied to  sites contaminated with radioactive wastes
depends  to  a great  extent  upon  the  physical,
chemical,  and  mmeralogical characteristics of the
matrix (e.g.,  soil) material. Other important factors are
the site location  (e.g., proximity to a population
center), the  volume to be remediated, the radioactive
elements,  the level of radioactivity, and the presence
of other hazardous substances.

This appendix  briefly  describes  the  sites  on the
Superfund NPL that  contain radioactive materials.  In
addition,  information  is presented  on  the DOE's
Formerly  Utilized  Sites  Remedial  Action  Project
(FUSRAP), its Uranium Mill Tailings Remedial Action
Project (UMTRAP), Grand  Junction Remedial Action
Project (GJRAP) and Surplus Facilities  Management
Program  (SFMP).   The  sites  and remediation
experiences  in  DOE's projects are very  similar  to
those of the Superfund program.  In fact a few of the
DOE sites are on the NPL.  Site information  presented
in this Appendix is accurate as of December 1987.

Radiologically Contaminated Superfund
Sites
The  information presented here has  been  compiled
from  the   various  written  status  reports  and
investigation reports obtained principally from the EPA
Regional  personnel  who have the responsibility  for
the described  sites.  The  descriptions are  limited  to
the 20 sites currently listed on or proposed for the
NPL  that  are known  to  contain  man-made
radioactive waste  materials. These sites are listed  in
Table B1,  which is followed by the site descriptions.

A distinction exists  between  man-made radioactive
wastes  and  naturally occurring and  accelerator
produced  radioactive  material  (NARM),  which has
been  technologically  concentrated  or otherwise
altered in  such a way that the potential for human
exposure  has  been  increased.  The  uranium and
thorium  series  are hallmarks  of  naturally  occurring
radioactive  materials.  The majority of the listed
Superfund  sites with radionuclide  contamination are
presumed  to be contaminated by  elements in these
series.  The  listed  sites  may  not be  the  only
Superfund sites  that are radiologically contaminated.
In fact, it may be expected that, as other  Superfund
sites are more fully characterized,  the list will expand.
On the other hand, there are a few  Superfund  sites
containing radioactivity of natural origin in measurable
amounts from the bedrock in the vicinity.

Two of the 20 sites described are landfills  containing
solid waste, hazardous waste, and radioactive waste.
Ten of  the  sites are  primarily  tailings  from  ore
processing.   Four  sites  include  radiologically
contaminated building materials. At least five of the
sites have been used as sources of fill material on
properties in their vicinities.

Contaminated site areas total more than 9,500 acres
and individually range from  about  one acre to 6,550
acres. The individual sites  range  from  less  than 50
cubic yards to more than 16 million cubic yards. The
largest volume sites (those  containing more than one
million  cubic  yards)  are  uranium  mill tailings sites.
There are five sites in New Jersey, four in Illinois, four
in Colorado,  and two in  New Mexico. The  remaining
sites are  located  in Massachusetts, Pennsylvania,
Kentucky, Missouri, and Utah.
1.   Radioactive Waste Superfund Site -
     Description

Name and Location:
    Shpack/ALI  (adjacent landfills), Norton/Attleboro,
    Massachusetts
EPA Contact Region I:
    Robert  Shatten, FTS  835-3679


Status:
    NPL Final, Rank 672

    Final  site response assessment report, 11/21/85,
    prepared by  NUS Corp.  for  performance of
    remedial activities. Monitoring program  included
    water samples from 10 observation wells and soil
                                                85

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            Table B1.   Radioactive Waste Superfund Sites

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11
12.
13.
14.
15
16.
17.
18.
19
20.
Site Name
Shpack/ALI (Adjacent Landfills)
Maywood Chemical CoVSears Properly
U.S. Radium Corp.
W. R Grace & Co. (Wayne Plant)
Montclair, West Orange, and Glen Ridge Radium Sites
Lodi Municipal Well
Lansdowne Property
Maxey Flats Nuclear Disposal Site
West Chicago Sewage Treatment Plant
Reed-Keppler Park
Kerr-McGee Off-Site Properties
Kerr-McGee Kress Creek/West Branch of Dupage River
The Homestake Mining Co. Uranium Mill
United Nuclear Corp.
Weldon Spring Quarry
Monticello Radioactivity-Contaminated Properties
Denver Radium Superfund Sites
Lincoln Park
U.S. DOE Rocky Flats Plant
Uravan Uranium Project
City/County
Norton/Attleboro
Maywood/Bergen Co.
Orange, Essex Co.
Wayne/Passaic Co.
Essex Co.
Lodi, Bergen Co.
Lansdowne
Fleming City/Hilisboro
West Chicago
West Chicago
West Chicago
West Chicago
Cibola Co.
Church Rock
St Charles City
Monticello San Juan, Co.
Denver
Canon City
Golden
Montrose City/Uravan
State/EPA
Region
MA/I
NJ/II
NJ/II
NJ/II
NJ/II
NJ/II
PA/111
KY/IV
IL/V
IL/V
IL/V
IL/V
NMA/I
NM/VI
MO/VII
UT/VIII
COA/III
CO/VIII
COA/III
CO/VIII
   samples analyzed for priority pollutants and gross
   alpha, beta, and gamma radioactivity.

   No  Remedial  Investigation/Feasibility  Study
   (RI/FS) available yet.


Radiation Data:
   Ra-226,  U-238,  U-235,  U-234 above  natural
   background  levels but  uneven  distribution in
   surface  and subsurface soil.  K-40, Th-228,
   Th-230  present.  Rn-222, 240  pCi/l  in  ground
   water. Some measured  values in soil:  Ra-226,
   1571 pCi/g;  U-238,  16,460 pCi/g;  U-235,  200
   pCi/g; U-234, 4,200 pCi/g.

Matrix Characteristics:

   Wetland  or  swamp area; sand, gravel, silt,  and
   clay,  organic   deposits.  Nonradioactive
   contaminants:  1,2-dichloroethylene, trichloro-
   ethylene,  tetrachloroethylene,  chromium,
   cadmium, nickel.

Source:

   Unknown,  possibly manufacture of  luminescent
   dials and former  operation  of nuclear submarine
   contractor.
Approximate Area and Volume:

Shpack about 8 acres; All about 23 acres; 100 tons.

Environmental Impact:

    10,000 residents relying on well  water  within 1-
    mi radius.  270 residents live  within  3-mi  radius.
    About 35 private wells within  3 mile radius of the
    site serve approximately 130  people. ORNL  1982
    survey revealed  no migration  of radionuclides into
    ground water; no hydraulic gradient  (vertical or
    horizontal)  in underlying aquifers. Rn-222  at 328
    pCi/l  in  ground  water in  1980 study by  private
    consultant  considered  suspect.  Airborne
    radionuclide contamination  no apparent threat to
    public.  Based on  existing  data  as  of 11/85,  no
    indication of immediate public health threat.

Source of Information:

    Final  Site  Response Assessment Report D583-
    1-5-22,  Revision  2;  prepared  by  NUS  Corp.,
    11/21/85.
                                                 86

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2.   Radioactive Waste Super-fund Site -
     Description

Name and Location:
    Maywood  Chemical Co./Sears   Property,
    Maywood, Rochelle Park, New Jersey


EPA Contact Region II:
    Pasquale  Envangelista, FTS 264-2649


Status:
    NPL Final, Rank 157.

    Site was identified under FUSRAP, and DOE was
    designated to perform remedial action related to
    radioactive residues.  Residential  properties  in
    Maywood, Rochelle  Park,  and parts of Lodi, NJ
    were remediated. Soil from  old  disposal  areas
    was removed.  Temporary  storage facility  called
    the  Maywood  Interim  Storage  Site  (MISS)
    developed.  DOE   conducting continuous
    monitoring at MISS and detailed characterizations
    of properties related to the Maywood site.
    one residence. Elevated gamma radiation levels
    on adjacent properties.


Source of Information:
    "Characterization  Report  for  Sears  Property,
    Maywood,  New Jersey,"  DOE/OR/20722-140,
    Oak  Ridge  National Laboratory,  May  1987.
    "Engineering  Evaluation  of Disposal Alternatives
    for Radioactive Waste from Remedial Actions  in
    and  around   Maywood,  New  Jersey,"
    DOE/OR/20722-79,  Oak  Ridge  National
    Laboratory, March 1986.

    EPA NPL Site Status Sheet
3.   Radioactive Waste Super-fund Site -
     Description

Name and Location:
    U.S.  Radium  Corp., Orange,  Essex Co.  New
    Jersey
Radiation Data:
    Elevated gamma radiation;  gross alpha in water,
    18.4  pCi/l.  Surface  soil  Th-232,  70 pCi/g;  Ra-
    226,  10 pCi/g; U-238, 77 pCi/g. Subsurface  soil
    Th-232,  180  pCi/g;  Ra-226, 37  pCi/g;  U-238,
    <232 pCi/g. Stream sediment Th-232,  93 pCi/g;
    Ra-226,  9  pCi/g; U-238  <57  pCi/g. Rn-222,
    0.9-300 pCi/I in ground water.


Matrix Characteristics:
    Tailings, soil,  clay-like  tailings;  used  as  fill
    material  in  several  residential  and commercial
    properties; stream  sediment;  water;  air.
    Nonradioactive contaminants  in  soil and tailings:
    arsenic, chromium,  nickel, lead,  cadmium,
    beryllium,  pesticides,  methyl chloride, xylene,
    toluene, ethyl benzene, acetone, MEK.


Source:
    Maywood Chemical Works; extraction of thorium.


Approximate Area and  Volume:
    42 acres (entire location), area  of  contamination
    not known;  270,000 cu yd.


Environmental Impact:
    36,000 residents within 4-mi radius.  Radon gas
    found by NRC at levels higher than background in
EPA Contact Region II:
    Douglas Johnson, FTS 264-1870


Status:

    NPL Final, Rank 423.

    Limited site characterization done at U.S. Radium
    and satellite properties by EPA and NJDEP. Final
    work plan for RI/FS prepared in  July 1987. Field
    investigation to begin in Fall 1987.


Radiation Data:

    New  Jersey  Department  of  Environmental
    Protection (NJDEP) has  found radon and  decay
    products  in  air in elevated concentrations and
    gamma  radiation  levels  around  property
    significantly  above background levels.  U-238,
    U-234, Th-230  and   Ra-226  present  in soil
    and concrete  and Rn-222 in air.

      Surface Soil:

         Ra-226  3.2-670 pCi/g
         U -238   minor

      Subsurface Soil (2-4.5  ft):

         Ra - 226    2090-3290  pCi/g
         U - 238  90-12000  pCi/g
                                               87

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Matrix Characteristics:
   Building materials,  grounds,  soil,  surface, and
   ground water.


Source:
   Former  radium ore processing plant,  lab and
   manufacturing facility,  and  radium  cottage
   industry.


Approximate Area and Volume:
   One acre; estimated 10,000 cu yd of tailing waste
   on-site.


Environmental Impact:
   32,000  residents  within  1/2-mi radius.  NJDEP
   has  found  radon  and  decay  products  in air in
   excessive concentrations; gamma radiation levels
   around  property greater  than  normal.  Satellite
   properties where  radium dial  painting  and lab
   work done may also be contaminated.


Source  of Information:
   EPA NPL  Site  status sheet.  EPA Office  of
   Radiation  Programs. "Final  Work  Plan for
   Remedial Investigation and Feasibility Study, U.S.
   Radium Corporation-site,  City of Orange, Essex
   County, New  Jersey," Camp Dresser & McKee
   Inc., for USEPA April 1987.

4.   Radioactive Waste Superfund  Site -
     Description

Name and Location:
   W.  R. Grace  & Co. (Wayne  Plant), Wayne, New
    Jersey


EPA Contact Region  II:
    Carole  Peterson,  FTS 264-6190


Status:
    NPL Final,  Rank 214

    Site was  partially  remediated  in 1986  by  DOE.
    Private residences along Sheffield  Brook, where
    thorium tailings  were  carried  by  surface  runoff
    cleaned in  1986.  Excavations  continued  in
    July/August 1987.  Completion  of excavation  is
    contingent upon locating a final disposal facility.
    Temporary storage of thorium tailings  will  be at
    Wayne Interim Storage  Site (WISS) awaiting  a
    permanent disposal  site  in NJ. Most of the  off-
    site material has been removed.
Radiation Data:
   Total U,  2.7 pCi/g;  Th-232,  3.78 pCi/g;  Ra-226,
   5.1  pCi/g;  Ra-228,  6.9  pCi/g; gamma radiation
   and  Rn-222 in  1985 were  less  than in  1984
   findings, due to remedial  activities at the site.
Matrix Characteristics:
    Sand  and  gravel;  tailings  from  processing
    monazite  ores; tailings  buried  on-site;  surface
    and ground water; air.
Source:
    Thorium  ore (monazite) extraction plant on-site.


Approximate Area and Volume:
    6.5 acres; 120,000 cu yd.


Environmental Impact:
    51,000 residents  within  3-mi radius.  Extensive
    soil  contamination.  The  potential for  further
    contamination  by runoff  has  been  abated
    somewhat by work done to date  at site.


Source of Information:
    "Wayne  Interim  Storage  Site  Annual  Site
    Environmental Report  Calendar  Year  1985,"
    DOE/OR/20722-103,  Oak  Ridge Operations
    Office. August 1986.

5.   Radioactive Waste Superfund Site -
     Description

Name and Location:
    Montclair/West Orange  Radium Site  and  Glen
    Ridge Radium Site, Essex County, New Jersey


EPA Contact Region II:
    Robert  McKnight,  FTS 264-1870


Status:
    NPL Final, Rank 178

    EPA released a draft Remedial Investigation and
    Feasibility Study (RI/FS) report  9/85. New Jersey
    Department of Environmental Protection  (NJDEP)
    began  remediation of  nine  residential properties
    by excavating contaminated soil 6/85.  EPA  RI/FS
    report considered remedial cleanup and disposal
    alternatives.   Due to  the  extent of  radium
    contamination,  EPA  has  been conducting
    additional field studies. As of 3/87, EPA has been
    unable to solve the soil  disposal problem and is
                                                 88

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    developing  a supplemental  RI/FS to focus  on
    continuing protective action while  final remedy is
    developed.
 Radiation Data:
    Rn-222  gas  in  homes,  0.5-440  pCi/l  before
    remediation;  radium in soil above background in
    40% of  properties;  Ra-226,  U-234  present.
    Gamma radiation  levels as high as 1300 pR/hr.

    Subsurface concentration:
      Ra 1 - 5386 pCi/g  (maximum)
      Th 1 - 4620 pCi/g(maximum)
      U 1 - 248  pCi/g(maximum)
Matrix Characteristics:

    Ash  and cinders  in  discrete  pockets;  also
    apparently mixed with soil  (silt, sand, and  gravel)
    or used alone as fill.
 6.   Radioactive Waste Superfund Site -
      Description

 Name and Location:
    Lodi Municipal  Well, Lodi,  Bergen County  New
    Jersey
 EPA Contact Region II:

    Richard Wice, FTS 264-1870

 Status.-
    NPL proposed.
    Well closed 12/83.

    RI/FS Work  Plan being prepared.  Field  activities
    scheduled to begin Fall 1987. RI/FS will determine
    whether the  source  of  contamination  may  be
    attributed to either a man-made contaminant or
    a naturally occurring source.
Source:
    Alleged to be  former  radium-processing  facility
    nearby.
Approximate Area and Volume:
    127 acres; 350,000 cu yd  total in three separate
    areas; over 750 properties involved.
Environmental Impact:
   Approximately 750 properties in three  areas.
   76,000 residents  within  3-mi  radius.  EPA,
   Centers for  Disease Control (CDC), Agency for
   Toxic Substances and Disease Registry (ATSDR)
   have  determined the long-term impact on  health
   of residents.
Source of Information:

   Superfund  Program  Fact Sheet  5/86;  update
   11/86 and 3/87.

   "Radon Contamination in Montclair  and  Glen
   Ridge  New Jersey Investigation  and Emergency
   Response," by J.V. Czapor and  K. Gigliello, and
   J. Eng.

   "Feasibility study for Montclair/West Orange, Glen
   Ridge, New Jersey Radium  Sites", Draft  Final
   Report, USEPA, 1985.
 Radiation Data:

    One  well out of nine contaminated with gross
    alpha radiation from U-238 decay.
Matrix Characteristics:

    Ground  water; VOCs  present  in most of nine
    wells.
Source:
    Possibly nearby  thorium-processing facility,  or
    may be natural source.

Approximate Area and Volume:
    One well radiologically contaminated; 2.35 sq mi.

Environmental Impact:
    One well closed due to radiological contamination.
    Other eight are shut down due to volatile organic
    contamination. Lodi using alternate water supply.

Source of Information:
    EPA NPL status sheet.

7.   Radioactive Waste Superfund Site -
     Description

Name and Location:
    Lansdowne Property,  105-107  E. Stratford Ave.,
    Lansdowne, Pennsylvania
                                               89

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EPA Contact Region III:
    Vic Janosik, FTS 597-8996
EPA Contact Region IV:
    Harold Taylor, FTS 257-2234
Status:
    NPL Final, Rank 703.

    Based  on  a  radiological  assessment  of  the
    property and  a remedial action plan prepared by
    Argonne National Laboratory  in  1985,  EPA  has
    decided  to dismantle the  duplex residence  and
    dispose  of contaminated materials at a licensed
    burial site (Hanford, WA).


Radiation Data:
    Elevated gamma radiation levels.  Soil, sewer
    lines,  building  materials contaminated  with  Fta-
    226,  Th-230, Ac-227,  and Pa-231.  Rn  at
    0.021  - 0.309 working level (WL). Concentration
    in soil:  Ra-226,  797  pCi/g;  TH-230, 30 pCi/g.


Matrix Characteristics:
    Soil, concrete, other building materials, sewer line
    waste.


Source:
    Basement  operation  for radium  purification  and
    packaging by former occupant.


Approximate Area and Volume:
    52,000 sq  ft of land; 2,000 cu yd contaminated
    soil, extending to 8 ft depth.


Environmental Impact:
    Severe contamination of building  and surrounding
    grounds. One family  in  area.  ATSDR issued
    (3/85) health advisory warning that radiation levels
    in the structure were unsafe.
Source of Information:
    Radiological  Assessment  Report and  Remedial
    Action  Plans  for the  Lansdowne  Property,
    prepared by Argonne National Laboratory.
8.   Radioactive Waste Superfund Site -
     Description

Name and Location:
    Maxey  Flats Nuclear Disposal Site, Fleming City,
    Hillsboro, Kentucky
Status:
    NPL Final, Rank 612 RI/FS work plan completed
    6/30/86  with  focus on  risk  assessment  and
    evaluation  of  alternative  remediation, based  on
    containment of waste. Consent order  entered into
    3/87  by EPA and  site steering  committee to
    perform RI/FS per work plan.


Radiation Data:
    Transuranic nuclides in the environment;  elevated
    concentrations of tritium,  cobalt  and strontium.
    Site  contains 2.4  million  Ci  of radioactivity
    including 430  kg of special  nuclear material and
    64 kg  of  plutonium.  Gamma radiation  10-32
    pR/hr; 30,000 pCi/cu m activity level.


Matrix Characteristics:
    Low-level  radioactive waste burial  facility;
    leachate,  soil, air;  flora, fauna. Nonradioactive
    contaminants: benzene,   naphthalene,  d-n-
    oxylphthalate, 1,4-dioxane,  dichlorodifluoro-
    methane,  1,1-dichloroethene,  pentanol,  ethyl-
    enediaminetetracetic  acid,  2-methylpropionic
    acid,2-methylbutanoic acid,  3-methylbutanoic
    acid,  valeric  acid,  isobutyric  acid, 2-methyl-
    butyric acid,  3-methylbutync  acid,  pentanoic
    acid,   2-methylpentanoic acid,  3-methyl-
    pentanoic  acid,  Cg-branched acids,  phenol,
    hexanoic acid,  2-methylhexanoic acid,  cresol
    (isomers), 2-ethylhexanoic  acid,  Co-branched
    acid, benzoic acid,  octanoic acid,  phenylacetic
    acid, phenylpropionic acid, phenylhexanoic acid,
    toluic  acid, p-dioxane, methyl  isobutyl  ketone,
    toluene, xylene  (isomers),  cyclohexanol,  dibutyl
    ketone,   fenchone,  triethyl   phosphate,
    naphthalene,  tributyl phosphate, a-terpineol.
                                                    Source:
    Disposal  site  for  various
    waste sources.
low-level  radioactive
Approximate Area and Volume:
    280 acres (total  site), 25 acres  (contaminated),
    178,000 cu yd.


Environmental Impact
    One  hundred residents  live  within 1-mi radius.
    Leachate  escaping through bedrock fractures into
    underlying sandstone and  trenches.  Leachate
    from  a number  of trenches  contains  soluble
    plutonium. Evidence of migration of tritium from
                                                 90

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   trench water to  wells has been  established  but
   not in high enough levels to pose a public health
   hazard.  Local  residents are  on public water
   supply system, however.


Source of Information:
   RI/FS Work Plan (6/86).

9.   Radioactive Waste Super-fund Site  -
     Description

Name and Location:
   West Chicago  Sewage Treatment Plant,  West
   Chicago, Illinois


EPA Contact Region V:
   Neil  Meldgin, FTS 886-4726


Status.
   NPL proposed. The Remedial Investigation Report
   has been completed. Samples were analyzed for
   metals, radon, thoron and thorium. Values were
   presented for As, Ba, Cd, Cr, Fe, Pb, Hg,  and  Se.

Radiation Data:
   The  nominal concentration of Th-232 in  the  soil
   was  4900 pCi/g;  Th-232,  0.03  pCi/l;  Th-230,
   0.4 pCi/l;  and Ra-226, 0.03 pCi/l  were measured
   in the ground  water;  gamma radiation, 2000-
   3000 pR/hr.


Matrix Characteristics:
   Soil; till; gravel;  ground water; monazite ore.


Approximate Area and Volume:
   25 acres (includes plant site and Reed-Keppler
   Park and not just contaminated area);  40,000 cu
   yd-

Source:
   The  Rare Earths Facility,  an  ore  processing
   facility that had been used to process thorium and
   rare  earth ores containing radioactive thorium,
   uranium, and radium.


Environmental Impact:
   There are several  routes of potential risks to  the
   environment  and public  health,  including  direct
   external  radiation exposure;  inhalation exposure;
   and  ingestion  of  contaminated  soils,  ground
   water, and  surface water. The contaminated
   media at the site are wastes from  the Rare Earths
    Facility.  The  primary  radionuchde  present  is
    thorium-232.
Source of Information:
    Remedial  Investigation  Report,  Kerr-McGee
    Radiation-sites,   West   Chicago,  Illinois,
    September, 1986 CH2M Hill.

10.  Radioactive Waste Superfund Site -
     Description

Name and Location:
    Reed-Keppler Park, West Chicago, Illinois


EPA Contact Region V:
    Neil  Meldgin, FTS  886-4726


Status.
    NPL proposed.  The Remedial Investigation Report
    has been completed. Samples  were analyzed for
    23  metals,  Th-232, U-238.  Ra-228,  and  Ra-
    226  in the soil; and  gross alpha, Th-232,  and
    Ra-226 in the ground water. Radiation  Data The
    concentrations of radioactivity in the ground water
    samples  were:  Th-232, 23 pCi/l  and  Ra-226,
    7.6  pCi/l.  In  the   soil  sample, Th-232 up  to
    11,000 pCi/g.  Gamma  exposure  levels up  to
    16,000 pR/hr.


Matrix Characteristics:
    Till, gravel, ground  water, and air.


Approximate Area and Volume:
    It is  estimated that 20,000 cu  yd of thorium-
    contaminated material is located within the Park in
    11,000 sq yd  area.

Source:
    The   Rare  Earths   Facility, an  ore  processing
    facility that had  been used to process thorium and
    rare   earth ores containing radioactive thorium,
    uranium,  and  radium.


Environmental Impact:
    There are several  routes of potential risks to the
    environment  and  public health  including direct
    external  radiation  exposure; inhalation exposure;
    and   ingestion  of  contaminated  soils, ground
    water, and surface water. The  contaminated
    media at  the site are wastes from the Rare Earths
    Facility.  The  primary  radionuclide  present is
    thorium-232.
                                                91

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Source of Information:
   Remedial  Investigation  Report, Kerr-McGee
   Radiation-sites,  West  Chicago,  Illinois,
   September, 1986 CH2M Hill.
11.  Radioactive Waste Super-fund Site -
     Description

Name and Location:
    Kerr-McGee  Off-Site  Properties,   West
    Chicago, Illinois


EPA Contact Region V:
    Neil Meldgin, FTS 886-4726


Status:
    NPL proposed. The Remedial Investigation Report
    has been completed. Mitigation procedures were
    carried out at 116 locations.


Radiation Data:
    Contamination  in excess  of 2000-3000  yR/hr
    was noted prior to the mitigative measures. Th-
    232 up to 16,000 pCi/g in soil was measured.


Matrix Characteristics:
    Till, gravel, fill, tailings.


Approximate Area and Volume:
    The area  consists of 117 residential  lots of
    various sizes. Approximately 61,000 cu yd.


Source:
    The  Rare Earths Facility,  an ore-processing
    facility that had been used to  process thorium and
    rare earth ores containing  radioactive  thorium,
    uranium, and radium.
Source of Information:
   Remedial  Investigation  Report,  Kerr-McGee
   Radiation-sites,  West  Chicago,  Illinois, Septem-
   ber, 1986 CH2M Hill.

12.  Radioactive Waste  Superfund Site -
     Description

Name and Location:
   Kress Creek and the West Branch of the DuPage
   River, West Chicago, Illinois


EPA Contact Region V:
   Neil  Meldgin, FTS  886-4726


Status:
   The  Nuclear  Regulatory  Commission  (NRC)
   issued an  order  to Kerr-McGee to  prepare  a
   cleanup  plan  for   Kress  Creek and affected
   portions of  the West Branch of the DuPage River.
   The NRC's Atomic Safety Licensing Board upheld
   Kerr-McGee's  challenge.  The  NRC  staff  has
   appealed this  decision. Should  the appeal  fail,
   EPA must  consider using Superfund  to remedy
   the creek and river contamination.


Radiation Data:
   About  1.5 mi of creek and river are contaminated
   in the streams  and along the banks.  Peak total
   thorium concentrations are  555 pCi/g  at a depth
   of 60  cm (2 ft). Thorium has been identified as
   deep as 170 cm (6 ft). Peak gamma  levels are
   250 pR/hr along the bank.

Matrix Characteristics:
    Sediment, soil, tailings.


Approximate Area and Volume:
    Undetermined  but  substantial. Affected area  is
    about  1.5  miles of creek and river bed and the
    adjacent banks.
 Environmental Impact:
    There are  several routes of potential risks to the
    environment  and public  health including direct
    external  radiation exposure;  inhalation  exposure;
    and  ingestion  of  contaminated  soils,  ground
    water,  and  surface water. The contaminated
    media at the site consists of wastes from the
    Rare  Earths Facility.  The  primary radionuclide
    present  is  thorium-232.
Source.
    The  Rare Earths  Facility,  an  ore  processing
    facility that had been used to process thorium and
    rare  earth ores containing  radioactive  thorium,
    uranium, and radium.


Environmental Impact:
    There are several routes for potential risks to the
    environment  and public health, including direct
    external radiation exposure; inhalation  exposure;
                                                92

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   and  ingestion of contaminated  soils,  ground
   water, and  surface  water.  The contaminated
   media at the site consists  of wastes from  the
   Rare  Earths  Facility. The  primary  radionuclide
   present is Th-232.


Source of Information:
   Comprehensive  Radiological  Survey of Kress
   Creek, West Chicago  Area,  Illinois, February
   1984, Oak Ridge  Associated  Universities.

13.  Radioactive  Waste Superfund Site  -
     Description

Name and Location:
   The  Homestake  Mining  Co.  Uranium Mill, Cibola
   County, New Mexico, about 5.5  miles north of
   Milan.


EPA  Contact Region VI:

   Ursula Lennox, FTS 255-6735

Status:
   NPL Final, Rank 528.  Homestake and EPA signed
   an  Administrative  Order  in June  1987  for
   implementation of a  workplan for  a  radon RI/FS
   developed by New Mexico's contractor, Geomet.
   A 15  month  Rl testing program will be started by
   Homestake  in  November  1987.  Naturally
   occurring dispersed tailings,  ground  water
   contamination,  and  tailings  piles may  be
   considered as to  how  they act as sources.


Radiation Data:
   Rn-222 in the air, 0.03  WL; radium in the  mill
   tailings, 60-100 pCi/g; uranium in  the water, 720
   ppb.  One year  monitoring  study  of indoor  and
   outdoor radon concentrations.  Outdoor radon
   concentrations  ranged  from   0.05  pCi/l
   (background) to 2.6 pCi/l.

Matrix Characteristics:
   Soil, tailings, ground water, and air.


Approximate Area and Volume:
   245 acres at 6,600 foot elevation;  16,500,000 cu
   yd.


Source:
   Potential sources are:

   Homestake Mining Company uranium mill  tailings,
   Anaconda mill tailings,  Ambrosia Lake  mining
   area,  and areas  of  near-surface  uranium
   mineralization.


Environmental Impact:
   About  two hundred people  depend  upon the
   shallow aquifer as a water supply. An alternate
   water supply is in place, and aquifer restoration
   by  Homestake has been  somewhat  successful.
   Radon levels indoors  and outdoors  in  several
   subdivisions  near  the mill  may  be above
   background.


Source of Information:

   Geomet  Report  Number IE-1739,  March 20,
   1987. "WORK  PLAN FOR HOMESTAKE MINING
   COMPANY STUDY AREA NEAR MILAN,  NEW
   MEXICO," RI/FS for E.I.D., R.P.B.,  State of New
   Mexico.
14.  Radioactive Waste Superfund Site -
     Description

Wame and Location:

   United Nuclear Corp., Church Rock, New  Mexico.
   The  site is  15  miles northeast of Gallup, New
   Mexico.

EPA  Contact Region  W.-

   Alan Tavenner, FTS 255-6735

Status:

   NPL  Final,  Rank 651  Remedial  Investigation
   begun  January,   1985.  United Nuclear  is
   developing  a reclamation  plan.  The RI/FS is
   scheduled for completion Spring, 1988

Radiation Data:

   Measurements  of ground  water showed levels as
   high  as  12.6 pCi/l for Ra-226 and Ra-228 and
   8.15  pCi/l for  uranium.  Th was  measured  at
   40,000 pCi/l  and Ra at 45 pCi/l. Data are shown
   for As, Cr, Se, Cd, Pb, N, and S04.
Radioactive
Contaminants
U-238
Th-230
Ra-226
Rn-222
Tailings
Pile (pCi/g)
29
290
290
no data


3.9
9.3
1.3
no
Pond
x 103
x 104
x 102
data
(pCi/l)
pCi/l
pCi/l
pCi/l
                                               93

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Matrix Characteristics:
                      Radiation Data:
   Tailings,  ground  water.  Nonradioactive
   contaminants:
         arsenic
         barium
         cadmium
         lead
         mercury
         molybdenum
         selenium
         vanadium
         zinc
Pond (mg/l)

1.22
0.29
0.11
1.56
0.5 x 10-3
2.30
0.53
46.94
7.22
Approximate Area and Volume:

   The mill  tailings  pond covers 170 acres and  is
   15-20 ft thick;  4,700,000 cu yd.

Source:

   The source of  the radiation is a uranium mill site,
   largely from the tailings ponds.

Environmental Impact:

   Several people use the shallow alluvial aquifers  in
   the area. A break in the tailings dam in  1979 sent
   93  million gallons  of tailings fluid into the  Rio
   Puerco. The upper  Gallup aquifer is contaminated
   in the vicinity  of the tailings pond.  The alluvial
   aquifer is also contaminated.

Source of Information:

   Site Status Summary, May, 1987 and  Technical
   Memorandum,  Phase I Field Study, RI/FS, United
   Nuclear, Church Rock, N.  Mexico,  October  4,
   1985, CH2M Hill.

15.  Radioactive Waste Superfund Site -
     Description

Wame and Location:

   Weldon Spring Quarry, St. Charles City, Missouri

EPA Contact Region VII:

   Katie Biggs, FTS 757-2823

Status:

   NPL Final. Under an agreement with  EPA (4/87),
   DOE  will  clean   up  quarry and  all nearby
   contaminated properties  and  develop an
   Environmental  Impact Statement incorporating all
   the requirements of a RI/FS.
   According to results of  monitoring by DOE and
   the U.S. Geological  Survey  (USGS), radioactive
   materials have  been released to  surface water,
   ground  water,  and  air.  Thorium,  uranium, and
   radium residues have been placed  in quarry.

Matrix Characteristics:

   Drums, process  equipment, building  rubble,
   debris,  raffinate sludges and soils  which  range
   from  gravelly to  clay-like and  organically  rich.
   Soils  and sludges are variably contaminated with
   TNT,  DNT, and  other organics.

Source:

   Uranium and thorium ore processing.  Previously
   US Army Ordnance works.

Approximate Area and Volume:

   220 acre complex; quarry is  9 acres; 780,000  cu
   yd radioactive material; 51,000 cu yd radioactive
   residues were  deposited in  quarry  along  with
   other  wastes.

Environmental Impact:

   Potential contamination of alluvial  aquifer 0.5  mi
   from quarry, serving 58,000 people.  Uranium and
   radium have been detected in off-site monitoring
   wells,  with  radium  concentrations exceeding
   drinking water standards.

Source of Information:

   Status report from EPA Region VII.

16.  Radioactive Waste Superfund Site -
     Description

Wame and Location:

   Monticello  Radioactivity-Contaminated  Prop-
   erties, Monticello,  Utah (San Juan County)

EPA Contact Region VIII.

   Lam Nguyen, FTS 564-1519

Status:

   NPL  Final,  Rank  502.  DOE  has  assumed
   responsibility for most of the remedial action. EPA
   is negotiating Memorandum of Agreement (MOA)
   with DOE  to better define  respective  roles  in
   clean-up activities.  DOE has authorized clean-
   up of 15 properties  and  is studying several more
                                                94

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   for inclusion in program.  EPA conducted  a
   planned  removal action  of two of  the most
   contaminated  structures  in Monticello  during
   1983-1984.

Radiation Data:

   Widely dispersed radioactive tailings;  U-238,  -
   234,  -226,  Th-230,  Rn-222,  Ra-226.

    Exposure Rates:
       Ra-226    1-23,000 pCi/g
       U-238     1-24,000 pCi/g
       U         18,OOOpCi/g


Matrix Characteristics:

   Tailings  from  vanadium  and  uranium  ore
   processing;  radioactive  tailings  widely  dispersed
   throughout town as fill material and as aggregate
   for mortar  and  concrete.  Vanadium  1-16,532
   ppm.

Source:

   Uranium  and  Vanadium  ore  processing  in
   Monticello plant from 1942 to 1960. Some tailings
   may have been  brought in  from  another mill in
   Dry Valley.

Approximate Area and Volume:

   152 potentially contaminated properties; 182,000
   cu yd.

Environmental Impact:

   1500 residents  within  1/2-mi  radius.  152
   potentially  contaminated  properties.  Widely
   dispersed contamination,  apparently  mostly in
   near-surface  soils.

Source of Information:

   4/87  Fact  Sheet.  EPA  Office of  Radiation
   Programs

17.  Radioactive Waste Super-fund Site -
     Description

Name and Location:

   Denver  Radium Superfund  Sites,  Denver,
   Colorado

EPA Contact Region VIII:

   Marilyn Null,  FTS 564-1698
Status:


    NPL Final, Rank 269. Feasibility Studies  have
    been completed  for ten fund-lead operable units
    and for four fund-lead operable  unit  ROD's are
    pending. Remedial  Design  is underway at four
    operable  units.  Negotiations  with  Potentially
    Responsible  Parties  are  underway  at the
    enforcement-lead  operable unit.


Radiation  Data:

    U-234,  -238,  Th-230,   Ra-226,  Rn-222
    present.   Maximum   gamma   radiation
    concentrations at properties  included in  the site
    ranged  from 57 pR/hr to  2,547  pR/hr, maximum
    radium  concentrations ranged from  79 pCi/g  to
    5,093 pCi/g, and maximum radon decay  progeny
    levels of 0.30 WL (grab) have been measured on
    the site.


Matrix Characteristics:

    Asphalt,  soil,  pond bottom  sediment,  building
    debris  and contents, ground  water, and  airborne
    particulates.


Source:

    Former Denver  National  Radium  Institute and
    other  processors  involved in radium  processing
    through World War I and  early 1920s, generating
    large quantities of radioactive residues.


Approximate Area and Volume:

    Approximate volume 106,000 cu yd,  covering a
    total of about  40 acres in 44 locations  within a
    4-mi radius of downtown  Denver.

Environmental Impact:

    Potential risk  to human  health,  including  direct
    exposure,  inhalation of  radon,  mgestion  of
    radionuclides and contaminated media.

Source of Information:

    Final  Feasibility  Study,  Denver  Radium  site,
    Operable  Unit X,  6/87; Final Feasibility Study &
    Responsiveness, Denver  Radium Site, Operable
    Units IV/V, Vols.  I & II, 9/86;  Remedial Alternative
    Selection   and   Community   Relations
    Responsiveness  Summary,  Operable Unit VII,
    3/86. Remedial Investigation Report April 1986.
                                               95

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18.  Radioactive Waste Superfund Site -
     Description

Name and Location:

   Lincoln Park, Canon City, Colorado

EPA  Contact Region VIII:

   Gene Taylor,  FTS 564-1519

Status:

   NPL Final, Rank 621. RI/FS submitted to EPA by
   the  State for review   3/86.  Memorandum  of
   Agreement  between State  and EPA 4/86,  the
   State of  Colorado  has  lead  responsibility for
   negotiations development and implementation of a
   remedy.

Radiation Data:

   Groundwater  quality studies per  1987  USGS
   report included  Ra-226 between 0.05 and  1.6
   pCi/l, and U-234  and   -238  between 0.4 and
   5,700 ng/l.

Matrix Characteristics:

   Contaminated ground water derived from  unlined
   tailings  ponds.  Nonradioactive  contaminants:
   molybdenum and selenium.

Source:

   Uranium mill (Cotter Corporation).

Approximate Area and Volume:

   900 acres; 1,900,000 tons.

Environmental Impact:

   386  residents within 3-mi radius. Contaminated
   ground water in the vicinity  and  down gradient.
   No permitted drinking  water  wells  in  the area.
   Company's monitoring  data indicate a plume of
   contaminants, including molybdenum, uranium,
   and  selenium extending  from  mill  and affecting
   private wells that were serving 200 people.

Source of Information:

   4/87  Fact Sheet.  "Ground-water  Flow and
   Quality  Near  Canon  City,  Colorado."  US
   Geological Survey,  WRI Report  87-4014, 1987.
   EPA Office of Radiation Programs.
19.  Radioactive Waste Superfund Site -
     Description

Name and Location:

   U.S. DOE Rocky Flats Plant, Golden, Colorado

EPA  Contact Region  VIII:

   James Littlejohn,  FTS 564-1519

Status:

   NPL proposed. Compliance agreement entered
   into by DOE,  EPA, and  Colorado Dept. of Health
   7/86,   defining  respective  roles   and
   responsibilities. DOE is  responsible for remedial
   actions. RI/FS work plans completed 2/87; results
   due  7/87. DOE has done some remedial  work
   such as  capping and  removing  plutomum-
   contaminated soil.

Radiation Data:

   Plutonium and tritium releases.

Matrix Characteristics:

   Soil and sediment; wastewater impoundments.

Source:

   Production of nuclear weapons triggers; plutonium
   recovery; amencium research.

Approximate Area and Volume:

   6,550 acres total area; 91 sites; over 1,000 waste
   streams.

Environmental Impact:

   Plutonium and tritium  have contaminated  soils
   and  sediments in   surface  water. Ground  water
   has  been  contaminated   with  nitrate.
   Approximately  80,000 people live within 3  mi of
   the facility.

Source of Information:

   4/87 Fact Sheet; 7/85 NPL Fact Sheet.

20.  Radioactive Waste Superfund Site -
     Description

Name and Location:

   Uravan Uranium Project, Montrose City, Uravan,
   Colorado
                                               96

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EPA Contact Region VIII:

    Holly Fliniau, FTS 564-1519

Status:

    NPL Final  Rank  275.  State  of  Colorado
    negotiating remedy with  responsible  parties. EPA
    and  State have  entered  into  MOA  4/86,
    designating State to pursue effective  remedy. The
    State of Colorado  has negotiated an agreement
    with Responsible Parties, and the agreement has
    been approved by  U.S. District  Court. EPA
    submitted comments to  State on remedial  action
    plan 12/86.
                                 U-234,  U-238;
Radiation Data:

    Radionuclides and Rn-222,
    Th-230;  Ra-226.
      Th  16,000  -   165,000 pCi/l
      U    1,500  -    16,000 pCi/l
      Ra     66  -      676 pCi/l

Matrix Characteristics:
    Ground water and air, raffinate, tailings, surface
    water. Selenium, nickel, ammonia, sulfates.

Source:

    Uranium and vanadium recovery plant; milling
    operations; little activity at present; owned and
    operated by Union Carbide Corporation.

Approximate Area and Volume:

    900 acres; 2,000,000 tons removed/10,000,000
    tons stabilized.

Environmental Impact:

    Town in remote area. 125 residents  within 3-mi
    radius.  All residents moved December 1986; no
    permanent residents. Ground water  and air
    contaminated with process waste, including
    uranium. Discharge and disposal of  large volume
    of process wastes releasing radiation.

Source of Information:

    4/87 Fact Sheet

Department of Energy Remediation
Programs

The DOE  has  four  major site  remediation  projects
involving radioactive materials. They are the  Uranium
Mill Tailings Remedial Action Project (UMTRAP), the
Formerly  Utilized  Sites  Remedial  Action  Project
(FUSRAP), the  Grand  Junction  Remedial  Action
Project  (GJRAP),  and  the  Surplus  Facilities
Management Program (SFMP).


Formerly Utilized Sites Remedial Action Project
(FUSRAP)
The  U.S. Army  Corps  of  Engineers,  Manhattan
Engineer District (MED)  and its successor, the U.S.
Atomic Energy  Commission  (AEC) conducted
programs  during  the 1940s and  1950s  involving
research,  development,  processing,  and storage of
radioactive ores  and  their processing  residues.
Virtually all of this work was performed for the  Federal
government by private contractors at  sites that were
either  federally,  privately,  or institutionally  owned.
Many  of these sites  and  nearby  properties  were
contaminated with radionuclides at low concentrations
and mostly of natural origin.

When  the contracts  for MED/AEG  activities  were
terminated, the sites were decontaminated according
to then-current  health and  safety criteria  and
released for  unrestricted use. However, as research
on the effects  of low-level  radiation progressed,
radiological criteria and guidelines for returning sites
to unrestricted use became more  stringent. In  1974,
the  AEC  initiated a program to identify  former
MED/AEC sites  and  to determine their radiological
status  based  on  a review  of  historical  records. In
1977  the AEC  changed to  the  US  DOE  which
subsequently  initiated  FUSRAP  [1,3]. Figure  B1
shows the locations of the FUSRAP sites [2].

The  most seriously  contaminated  sites,  located in
New Jersey and New York, were involved in  storing,
sampling,  and processing very  rich pitchblende ores.
As of June 1987, a total  of 29 sites in 12 states were
designated for  remedial  action [J.  Wagnor,  DOE,
Personal Communication, July  2,  1987]. Preliminary
estimates are that 29 authorized sites may contain a
total  volume of  1.1  million  cu yd of  low-level
contaminated  dirt,  sediment, and  rubble. Of these,
remediation has been completed to the satisfaction of
the  DOE  at seven sites [A. Wallo,  DOE, Personal
Communication,  July  2,  1987].  The  disposition of
these seven sites as per DOE is as follows:

        Radiologically  contaminated  materials from
        Kellex  Research (Jersey City,  NJ),  Bayo
        Canyon, and Acid  Pueblo  Canyon  (Los
        Alamos, N.M.) were  excavated and removed
        to an authorized disposal facility.

        Radiologically contaminated  material  from
        Middlesex Landfill  (Middlesex,  NJ)  was
        excavated  and stored  at an  interim  storage
        site (above grade with a leachate  collection
        system).
                                                 97

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 Figure B1.    FUSRAP sites as of 1 982. (Reprinted from [2].)
   Albany Metallurgical Research
    Center, Albany, OR
   University of California, Berkeley, CA
    (Completed)                        7
   Acid/Pueblo Canyon, Los Alamos,
    NM (Completed)                     8
   Chupadera  Mesa, White Sands       9
   Missile                            10
    Range, NM (Completed)
   Hazelwood (Latty Avenue), MO          11
   St Louis Airport Storage Site,
    (Vicinity Prop ), St Louis, MO
   St Louis Airport Storage Site,
    St. Louis, MO
   Mallmckrodt, Inc , St. Louis, MO         12
University of Chicago, Chicago,  IL     13
 (Completed)
National Guard Armory, Chicago, IL      14
General Motors, Adrian, Ml
Niagara Falls Storage Site, (Vicinity
 Prop ), Lewiston, NY                 15
Ashland Oil Co #1, Tonawanda, NY      16
Seaway Industrial Park, Tonawanda,     18
 NY                              19
Linde Air Products, Tonawanda, NY      20
Ashland Oil Co #2, Tonawanda, NY
Universal Cyclops, Allquippa, PA        21
                                 22
W R Grace & Company, Curtis Bay,
 MD
Middlesex Landfill, Middlesex, NJ
Middlesex Sampling Plant,
 Middlesex, NJ
Du Pont & Company, Deepwater, NJ
Maywood, NJ
Wayne/Pequannock, NJ
Colome, NY
Seymour Speciality Wire, Seymour,
 CT
Shpack Landfill, Norton, MA
Ventron, Beverly, MA
       Radiologically  contaminated   laboratory
       buildings at  the  University  of  California
       (Berkeley, CA) and the University of Chicago
       (Chicago, IL) were surface  cleaned (washed,
       scraped, chipped).

       Investigation showed  that  the seventh site,
       Chupadera Mesa  (White  Sands,  NM),
       required no  cleanup.

The  remaining  twenty-two  sites  are  undergoing
remediation  or are awaiting remediation. Three of the
twenty-two are also Superfund sites:

1.  Shpack  Landfill, Norton/Attleboro, MA.
2.  Maywood Chemical Company, Maywood, NJ.
3.  W. R. Grace & Company, Wayne, NJ.

Remediation at  vicinity properties  consisted  of land
disposal or burial in  a land encapsulation approved for
radioactive waste. In some cases site buildings were
decontaminated  and returned to use,  and  in other
cases they were demolished and the rubble stored or
buried.
               Removal  and containment  of contaminated materials
               has been the strategy used thus far at FUSRAP sites.
               None of the other techniques described in this report
               has been attempted  in full-scale remediation.


               Uranium Mill Tailings Remedial Action Project
               (UMTRAP)

               The  use  of uranium for weapons  research  and
               production  resulted in  the   generation  of  huge
               quantities of uranium mill tailings,  the waste material
               remaining after uranium is extracted from the uranium
               ore. The  Atomic Energy  Act of 1954 authorized  the
               AEC  to  license the  receipt or transfer of  ores that
               contained  0.05% or  more of uranium and/or thorium.
               However,  the  AEC  exempted any  unrefined  and
               unprocessed ore and processed uranium mill tailings,
               which were assumed to contain less than the required
               percentage of uranium and  thorium. Due  to  this
               exemption, the uranium industry was not required to
               isolate or even to retain control of uranium tailings.

               Although  most  of  the uranium has  been removed
               from the tailings, the  radium remains and is a  source,
               through  radioactive   decay,   of  radon gas. Also,
                                                   98

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radionuclides and other trace elements present in the
tailings can be leached from the pile and contaminate
the ground water [2].

In 1978, Congress passed  Public Law 95-604, the
Uranium Mill  Tailings  Radiation Control Act  of 1978,
based on the finding that uranium mill tailings located
at mill sites posed a potential health  hazard to the
public.  Title  I of  the Act  instructed the  DOE to
perform  remedial  actions at  the  designated sites,
which contained a  total of approximately 25 million cu
yd of tailings. The  program to carry out these actions
is the Uranium Mil! Tailings  Remedial  Action Project
(UMTRAP).

The remediation  also  includes  cleanup of those
contaminated  properties outside  the designated
boundaries of the processing sites  that  became
contaminated through  the use of tailings for fill and/or
construction.  Approximately  8000 of  these "vicinity"
properties  have  been  identified  for  surveying to
confirm  the presence of tailings  and  contamination
levels requiring remedial action [2,4].

Of  the  24 UMTRAP  sites,  one  is in Pennsylvania
(Canonsburg)  and  23 in the western  United States
(Figure B2). The sites range in  size from  10  acres to
over 500 acres and include tailings piles,  evaporation
ponds,  windblown  contaminated  areas, and former
mill  buildings  and  associated  structures.  Depths of
tailings piles range  from a few feet to  over 275 feet in
Durango, Colorado. Many of the sites  have  exposed
tailings.  Some sites are covered with a foot  or so of
soil or sparse vegetation.

Some of the UMTRAP sites, such as Grand  Junction
and  Rifle, Colorado, are adjacent to  river systems.
Many, such as Canonsburg, PA; Gunnison, CO;  and
Shiprock, NM, are near small rivers  or creeks,  and
many sites have shallow water tables [5].

Remedial action  began at the  first site in  1983,  and
cleanup  of all sites is scheduled  for  completion in
1993 [6].  For tailings piles,  remediation consists
principally of  stabilization through  the  use of liners
and  covers  to prevent  migration and limit radon
emanation. This  approach  is  consistent  with  EPA
regulation  40 CFR   192.  For vicinity properties,
remediation consists  principally of excavation  and
disposal  of contaminated material to  tailings piles,
cleaning  of  buildings,  and,  where  necessary,
destruction of buildings and removal of the rubble.


Grand Junction Remedial Action Project
Between the years 1952  and 1966, several  hundred
thousand tons of  tailings were removed  from  the
Climax Uranium Company's mill tailings pile in Grand
Junction,  Colorado and used locally as  fill  and
construction material.  In  1966, when  the Colorado
Department of Health and  the U.S.  Public  Health
 Service  discovered  this  fact,  the  practice  was
 stopped, and investigations were begun to determine
 the potential radiological health effects of  tailings use
 in residential and commercial or civic construction. In
 1972, the U.S.  Surgeon General issued guidelines for
 determining the need  for corrective  action at those
 locations  where  increased  levels  of  radiation  were
 measured as a result of the presence of tailings. The
 U.S.  Congress  passed  PL  92-314   in  1972,
 authorizing Federal appropriations to assist the  State
 of Colorado in conducting a remedial action project at
 Grand  Junction.  The  objective  was  to perform
 corrective action at  sites where  radiation  exposures
 exceeded the  Surgeon General's  guidelines.  The
 project is  a  State-operated  activity,  with  DOE
 providing 75 percent of  the funding and the State, 25
 percent [7].

 In order to obtain the benefits  of  the   project,  a
 property owner had first to apply to  the Colorado
 Department of Health for a determination of eligibility.
 The criteria for  eligibility  (the Surgeon  General's
 guidelines) were based  on annual  average exposures
 to external gamma radiation, or inhalation  of airborne
 radon  daughter  products  resulting  directly  from
 uranium  mill tailings used in  the  construction  of  a
 building.  Of these  two  modes  of  exposure,  the
 inhalation  of airborne radon daughters  is  by  far the
 more important in terms of  numbers of locations
 exceeding  the  criteria  and in  terms of potential
 population exposure [8].

 The cleanup project began in 1973. The assessment
 project had identified  740  structures that  would
 require  some  form of  remedial action to meet the
 Surgeon General's guidelines.  Schools and the more
 highly contaminated dwellings were given first priority.
 The project  was to have been completed  by the end
 of fiscal year 1987.

 Whenever possible, the  contaminated sites have been
 cleaned up  by  excavation and removal  of tailings.
 Remediation has been  confined  to the area  of the
 structure and out to a distance of ten feet surrounding
 it. In many cases, the  structure has been  shored up
 and  material actually excavated from beneath  it. The
 original  tailings site was  used to  store the   tailings
 from the cleanups. That site, in turn,  will be cleaned
 up  under  UMTRAP  [T. Brazley, DOE,  Personal
 Communication, July 23, 1987].

 Where removal  of the  tailings is  not possible,  the
 structures have been remediated by applying sealants
 or increasing ventilation  and  filtration to reduce radon
gas in the structures to acceptable  levels [7].

 Starting in about 1975,  the  Colorado Department of
 Health, DOE, and the USEPA conducted a survey of
approximately 40,000 properties. The survey identified
about 6,000  vicinity properties as  "core sites," which
were  contaminated to   some degree.  Some  of the
                                                 99

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Figure B2.    Locations of DM TRAP sites. (Reprinted from [2].)
  1  Lakeview, OR (Medium Priority)
  2  Lowman, ID (Low Priority)
  3  Salt Lake City, UT (High Priority)
  4  Grand River, UT (Low Priority)
  5  Grand Junction, CO (High Priority)
  6  Natunta, CO (Medium Priority)
  7  Slickrock, CO (Low Priority) (2 sites)
  8  Mexican Hat, UT (Medium Priority)
  9  Monument, AZ (Low Priority)
 10  Tuba City, AZ (Medium Priority)
11  Ambrosia Lake, NM (Medium
   Priority)
12  Shiprock, NM (High Priority)
13  Durango, CO (High Priority)
14  Gunnison, CO (High Priority)
15  Rifle, CO (High Priority) (2 sites)
16  Maybell, CO (Low Priority)
17  Riverton, WY (High Priority)
18  Spook, WY (Low Priority)
19  Bowman, ND (Low Priority)
20  Belfield, ND (Low Priority)
21  Edgemont, SD (High Priority)
    (Vicinity Properties Only)
22  Falls City, TX (Medium Priority)
23  Canonsburg, PA (High Priority)
properties  remediated under the  Grand Junction
Remedial  Action project  are included in UMTRAP,
e.g., where remediation is necessary beyond ten feet
from the structure.  The  list  has been  narrowed  to
about 3,800  properties requiring  remediation.  About
2,000  have  been  recommended  by  ORNL  for
inclusion in  the  UMTRAP  cleanup.  This remedial
project has been initiated.

A second part of the  UMTRAP effort is  remediation
(which may include  relocation) of the original tailings
pile from which all of the problem tailings originated.
The actual fate of the tailings pile has not yet been
decided.


Surplus Facilities Management Program (SFMP)
The overall  objective of the SFMP  is to  provide  the
program direction,  planning,  and resources  for  the
DOE surplus facilities to (1) maintain surplus facilities
in  a  safe  condition  pending  decommissioning,  (2)
maximize the options for future use  of real property,
and (3) dispose of all  radioactive facilities and waste
in   accordance  with  accepted practices.  Other
objectives  include  (1)  providing  research  and
development  funding  for  property  and  equipment
decommissioning techniques and technology transfer,
and  (2)  conducting  cooperative  information
                 exchanges  on decommissioning  activities with other
                 countries and international organizations.

                 The current  inventory  of surplus  facilities  in  the
                 program  was  established  by review  of facilities in
                 1977 and by subsequent addition of  some facilities
                 from defunct  programs.  Thirty-five  projects  at  17
                 sites are included in the civilian  portion of the  SFMP.
                 The  sites  were  prioritized  based  on  (1)  the
                 assessment of potential for  exposure to the public
                 and workers at the site, (2) contractual commitments,
                 (3) reducing the cost of continuing surveillance  and
                 maintenance, and  (4) making the property  available
                 for alternative or unrestricted use.

                 Decommissioning has been conducted at the Special
                 Power  Excursion  Reactor Test  Area  in  Idaho, at
                 Argonne  National  Laboratory-East in  Illinois,  vicinity
                 properties at Monticello, Utah,  and buildings  at the
                 Santa  Susana  Field  Laboratory,   in  California.
                 Entombment  projects have been  completed  at the
                 Bonus  Facility in  Puerto Rico,  the Hallam  Facility in
                 Nebraska,  and the  Piqua  Facility in  Ohio.   Major
                 activities continue  at the  Idaho  National Engineering
                 Laboratory  in  Idaho, the Mound  Laboratory in Ohio,
                 Santa Susana in  California,  Monticello  in Utah,  and
                 ANL-East in  Illinois [9].  The  Shippingport Station
                 Decommissioning  Project will place the  station in a
                                                   100

-------
long-term radiologically safe condition by dismantling
and removing the radioactive portions of the plant.
One of the purposes of the Project is to demonstrate
to  the  nuclear industry  the practical and affordable
dismantlement of a large nuclear power plant. Actual
physical decommissioning activities were initiated in
September 1985.

Other near term activities include initiating work at the
Weldon Spring Site. This site was first used by the
Department of the Army as an ordnance works and,
later, by a  DOE predecessor agency  as a  uranium
feed  materials plant.  The site is contaminated with
thorium, uranium, and  decay  products. Near-term
activities   include  further  characterizing  the
contamination on  the  site,  initiating conceptual
engineering studies, establishing a project office at
the Weldon  Spring site, and completing the  NEPA
documentation.

Both the Weldon Spring  and Monticello sites  are also
Superfund sites.  The Surplus Facilities Management
Program  is scheduled for  completion  in the early
2000's.

Summary of Remediation Methods Used
to Date
Most of the  remedial  technologies to date have
consisted  of  excavation  and/or  removal  of
contaminated  materials  from  plant  sites  and  from
property owned  by  others in  the  vicinity  of those
properties. In  some cases, the contaminated material
has  been  temporarily  stored in  above-ground,
covered piles.  In  others,  the  material has been
permanently placed in secure land encapsulations.

No extraction or solidification technology has been
applied to  any  of  these  sites.  Some laboratory
experimentation  on  radionuclide  extraction from
tailings and soils have been conducted, as described
in  Chapters 5, 6, and 7.
References

1.  U.S. Department  of Energy. Pathways  Analysis
   and  Radiation Dose  Estimates  for Radioactive
   Residues  at  Formerly Utilized  MED/AEC Sites.
   ORO-832, Revised,  1983.

2.  U.S. Department  of Energy, Office of Remedial
   Action and Waste  Technology Program Summary,
   DOE/NE-0075. November 1986.

3.  U.S.  Department  of  Energy.  Methods  for
   Assessing Environmental  Impacts of  RAP
   Property  Cleanup/Interim  Storage  Remedial
   Action.   ANL/EIS-16,  Argonne  National
   Laboratory, 1982.

4.  Stassi  P.J.,  M.A. Jackson,  and  A.O.  Clark.
   Remedial Action  at  Vicinity  Properties.
   Proceedings  of  the  Symposium  on  Waste
   Management, Tucson,  AZ. March 24-28,  1985.

5.  Meyer, H.R.,  D.  Skinner,  J.  Coffman,  and J.
   Arthur. Environmental  Protection  in the UMTRA
   Project.  Proceedings  of  the  Fifth DOE
   Environmental Protection Information Meeting,
   Albuquerque,  NM., November 6-8, 1984.

6.  Matthews, M.L. UMTRA Project: Implementation
   of Design. Geotechnical and   Geohydrological
   Aspects of Waste Management.  Proceedings of
   the Fifth  Annual  Symposium, Fort Collins,  CO.
   February  5-7,  1986.

7.  U.S. Department  of Energy, Program Summary
   -  Nuclear Waste  Management,  Fuel  Cycle
   Programs.  DOE/NE-0039.  Assistant Secretary
   for Nuclear Energy, Washington, D.C., July 1982.

8.  U.S.  Department of  Energy,  Grand Junction
   Remedial Action  Program -  Analysis of Currently
   Approved  and   Proposed  Procedures  for
   Establishing   Eligibility  for Remedial  Action.
   DOE/EV10162-T1. Assistant   Secretary  for
   Environment,  Washington, D.C.,  December 1980.

9.  U.S. Department  of Energy. Office  of  Defense
   Waste  and  Transportation  Management.  1987
   Program Summary Document. April 1987.
                                               101

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Chemical Extraction

Abel,  K.H.  Techniques for chemical  analysis  of
radionuclides in fly ash: An evaluation.  Battelle Pacific
Northwest Labs, Final Report.

Allard, B.H., H. Kipatsi, and B. Torstenfelt. Sorption of
long-lived  radionuclides in  clay  and  rock.  Part  2.
Kaernbraenslesaekerhet, Stockholm, April 1978.

Beak  Consultants Ltd (sponsor). Assessment of the
long-term  suitability  of present and   proposed
methods for the management of uranium mill tailings.
Atomic Energy Control Board, Ottawa.

Beard, H.R., I.L Nichols, and D.C.  Seidel. Absorption
of radium  and thorium  from Wyoming  and  Utah
uranium mill tailings solutions.  Bureau of Mines, Salt
Lake City Research Center Report,  1979.

Beard, H.R.,  H.B.  Salisbury,  and  M.B.   Shirts.
Absorption  of radium and thorium  from New  Mexico
uranium mill tailing solutions. Bureau  of Mines, Salt
Lake City  Research Center  Report of Investigations,
1980.

Bryant,  D.N.,  D.B.  Cohen,  and R.W.  Durham.
Leachability  of radioactive constituents from  uranium
mine  tailings.  Environmental  Protection  Service
Report. Ottawa, April 1979.

Chin,  N.W.,  J.R. Dean, and  C.W.  Sill. Techniques of
sample attack used  in  soil  and  mineral analysis.
Phase 1. Atomic Energy Control Board, Ottawa.

Cline, J.E.  Development of  new and  improved data
reduction techniques for radiometnc  assay  of bulk
uranium ore samples. Science Applications, Inc., Dept
Energy Final Report,  Washington  DC, September
1977.

Cokal, E.J., D.R.  Dreesen,  and J.M.  Williams.
Chemical characterization and  hazard  assessment of
uranium mill tailings.  Los  Alamos Nat  Lab.  Dept
Energy Report, Washington DC, 1981.

Conference of Radiation  Program  Directors, Inc.
Natural radioactivity contamination  problems.  Report
sponsor:  Nuclear  Regulatory  Comm;  Office  of
Radiation  Programs,  Washington  DC;  Bureau  of
Radiological Health, Rockville. February 1978.

De Oliveira Godov, J.M. Development  of an analytical
method for the  determination  of U-238,   U-234,
Th-232,   Th-230,  Th-228,  Ra-228,  Ra-226,
Pb-210,   and  Po-210  and  its  application on
environmental  samples.  Kernforschungszentrum
Karslruhe GMDH  (Germany,  FR).  Hauptabeilung
Sicherhert, February 1983.

Demopoulos, G.P.  Acid Pressure  leaching of  a
sulphidic uranium  ore  with  emphasis  on  radium
extraction. Hydrometallurgy, v15 n2, December 1985.

Erickson, R.L.,  and D.R. Sherwood. Interaction  of
acidic  leachate  with  soil  materials  at  Lucky  Me
Pathfinder mill, Gas Hills, Wyoming. Battelle Pacific
Northwest Labs.  Dept  Energy Report,  Washington
DC, September 1982.

Fyfe,  W.S.  Immobilization  of U-Th-Ra  in mine
wastes by mineralization. In:  Geoscience Research
Grant Program;  Summary  of Research,  (ed. E.G.
Pye.) Ont Geol Surv Misc Paper, 87, 1979.

Graham,  E.R. Radioisotopes and soils.  In: Chemistry
of the  Soil,  2nd edition. Reinhold  Pub  Corp, New
York, 1964.

Hague,  K.E., and  B.  Ipekoglue. Hydrochloric  acid
leach  of Agnew Lake  uranium concentrate.  Can
Centre Mineral Eng Tech  Report, Ottawa,  October
1981.

Hawley, J.E.  Use of phosphate compounds to extract
thorium-230  and  radium-226  from uranium  ore and
tailings. Hazen Research, Inc., Nat Sci Found  Report,
Washington DC, May 1980.

Haywood, F.F., W.A. Goldsmith, R.W. Leggett, R.W.
Doane, and  W.F. Fox.  Sites,  Gardinier, Inc., Tampa,
Florida.  Oak  Ridge  Nat Lab. Dept  Energy  Report,
Washington DC, March 1981.

Hernsk,  J.F. Solubility limits on radionuclide
dissolution. Los Alamos Nat Lab. Dept Energy Report.
Washington DC, 1984.

Humphrey,  H.W., E.L.  Adkins,  and  G.G.  Templm.
Radiometnc determination of exp 226  Ra and exp 228
RA in waste  effluent solutions. Nat Lead Co  of Ohio,
Cincinnati, April 1975.

Joshi, L.U.,  and  A.K.  Ganguly. Natural radioactivity
and  geochemical processes  in  the  marine
environment  of  the  West  Coast of India.  Bhabba
Atomic Research Centre, Bombay, 1973.

Kalkwarf, D.R. Solubility classification  of airborne
products from uranium  ores and tailings piles.  Battelle
Pacific  Northwest  Labs. Dept  Energy  Report,
Washington DC, January 1979.

Landa, E.R.  Leaching  of radionuclides from  uranium
ore and mill tailings. U.S. Geol Surv, Denver,  1982.

Laul, J.C., C.W.  Thomas, M.R.  Peterson, and R.W.
Perkins. Radionuclide  disequilibria  studies  for
                                                106

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 investigating  the  integrity  of potential nuclear  waste
 disposal  sites:  subseabed studies.  Battelle  Pacific
 Northwest  Labs,  Dept  Energy Report,  Washington
 DC, September 1981.

 Leggett,  R.W.,  W.D.  Cottrell,  J.  Burden, and  M.T.
 Ryan.  Formerly  utilized  MED/AEC sites  remedial
 action  program:  radiological  survey of  the  former
 Lmde uranium refinery,  Tonawanda,  New York. Oak
 Ridge Nat Lab. Dept Energy Final Report,  Washington
 DC, May 1978.

 Leggett,  R.W.,  W.D.  Cottrell,  W.A.  Goldsmith, D.J.
 Christian,  and  F.F.  Haywood.  Formerly  utilized
 MED/AEC sites remedial action program. Radiological
 survey of the Middlesex Municipal Landfill, Middlesex,
 New  Jersey. Oak Ridge Nat  Lab. Dept  Energy
 Report, Washington DC, April 1985.

 Moffett,  D.  Disposal  of  solid  wastes  and  liquid
 effluents  from milling of uranium ores.  Can  Centre
 Mineral & Energy  Tech. Ottawa, July 1976.

 Murphy,  K.L., and G.E.  Muttamaki.  Placement  of
 radium/barium  sludges in tailings  areas.  Atomic
 Energy Control Board Report, Ottawa, March 1980.

 Murry, F.H., J.R. Brown, W.S.  Fyfe, and B.I.
 Kronberg. Immobilization of l-Th-Ra  in mine wastes
 by  phosphate mineralization.  Univ  West Ont, Dept
 Geol.

 Phillips, C.R., P. L. Sears,  and Y.  C. Poon. Leaching
 of uranium  ore with emphasis on the fate of radium.
 Energy Sources, v6 n3, 1982.

 Phillips,   C.R., and Y.C.  Poon.  Status  and  future
 possibilities for the recovery of uranium, thorium, and
 rare earths  from Canadian  ores, with emphasis on the
 problem  of radium. Minerals Sci Eng, v12 n2, April
 1980.

 Raicevic, D., M. Raicevic,  and  D.R.  McCarthy.
 Preconcentration  of low-grade uranium ores  with
 environmentally  acceptable tailings,  Part I.  Agnew
 Lake  ore.  Dept  Energy,   Mines,  and  Resources
 Report, Ottawa,  August 1979.

 Ramey,  R.H.,  and  R.G.  Nicol.  Separation   of
 daughters of /Sup 232/U  from/Sup 233/U  by  ion
 exchange. Oak Ridge Nat  Lab. Presentation, October
 1971.

 Scheitlin,  F.M.,   and  W.D.   Bond.  Removal   of
 hazardous radionuclides  from uranium ore and/or mill
tailings.   Oak Ridge Nat  Lab.  Dept Energy  Prog
 Report, Washington DC,  January 1980.

Smithson,  G.L.  Radiochemical  procedures  for
determination of selected  members of the  uranium
 and thorium  series. Can  Centre Mineral  &  Energy
 Tech, Ottawa, January  1979.

 Sears, M.B.,  E.L. Etnier, G.S. Hill, B.D. Patton, and
 J.P. Witherspoon.  Correlation of radioactive-waste-
 treatment costs and  the  environmental impact  of
 waste effluents in the  nuclear fuel cycle: conversion
 of yellow cake to uranium hexafluoride. Part  II. The
 solvent  extraction-fluorination  process. Oak  Ridge
 Nat Lab. Dept Energy Report, Washington DC, March
 1983.

 Starik, I., and K. F. Lazarev. Study of the comparative
 leachability of the isotopes of radium,  uranium, and
 thorium   from  monazite. In:  Melody  Oprei  Leniya
 Absolyutnogo Vozrasta  Geologicheskikh Obrazsvantz.
 Moscow, Akad Nauk SSSR Kom PO  Opredeleniya.
 ABS Vozrasta Geol  Formatsii, 6, 1964.

 Stieff,  L.R.  Studies of an  improved  polonium-210
 analytical procedure and the  distribution and transport
 of uranium and its alpha emitting daughters  using
 nuclear  emulsions.  Stieff  Research &  Development
 Co.,  Inc. Dept Energy Report, Washington  DC,
 September 1981.

 Torma, A.E.,  I.M. Gundiler, D. J.  Kirby,  J.J.  Santana,
 and  S.Y. Yeu.  Hydrochloric  acid  leaching  of  a  low-
 grade New Mexico  uranium  ore.  Metallurgy, v37 n2,
 February 1983.

 Tsezos,  M.  Selective  extraction of   metals  from
 solution   by microorganisms:  A brief  overview.  Can
 Metallurgical Quarterly,  v24 n2, Apr-June 1985.

 Vandergraaf,  T.T.   Mineralogical  and  geochemical
 aspects  of the disposal of  nuclear-fuel waste.  The
 Canadian Mineralogist, 21,  1983.

 Wiles, D.R. Radiochemistry of radium and thorium  in
 uranium mine tailings. Water, Air, & Soil  Pollution, v20
 n1, July 1983.

 Willis, C.P.  Radium and  uranium determination  in
 samples  of Utah Roses geothermal water. Idaho Nat
 Eng Lab. Dept Energy, Washington DC, June 1980.


 Ion Exchange

Arnold, W.D.  and D.J. Grouse. Radium  removal from
uranium mill effluents with  inorganic ion  exchangers.
 Ind Eng Chem Process  Design Devel., 4, July 1965.

Arnold, D.R.  The development of high  density  ion-
exchange for  CIX process. Proc 3rd Nat Mtg,  South
Africa Inst Chem Eng, Univ Stellenbosch, 1980.

Campbell, D.O., E.D. Collins, L.J.  King, J.B. Knauer,
and R.M. Wallace.  Evaluation  of the use of zeolite
mixtures  in the submerged  demineralizer system
(SDS)  flowsheet  for  decontamination of  high-
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activity-level water  at  Three  Mile  Island  Nuclear
Power  Station, Unit 2.  Paper,  Internal Zeolite Conf,
Reno, July 1983,

Haines,  A.K.  The  development of  continuous
fluidized-bed ion  exchange in South Africa.  J  South
Africa Inst Min Metall, 78, July 1978.

Hooper,  E.W.  The  application  of  inorganic  ion
exchangers to  the treatment of alpha-bearing  waste
streams.  Paper, Internal Atomic Energy Assoc Comm
Mtg, On Inorganic Ion Exchangers and Adsorbents for
Chem  Processing in the Nuclear Fuel  Cycle. IAEA
TC-518-10,  Vienna, 1984.

Hooper,  E.W.,  B.A. Phillips,  S.P.  Dagnall,  and N.P.
Monckton.  An  assessment of  the  application  of
inorganic ion  exchangers to  the  treatment  of
intermediate level wastes. AERE R11088, May 1984.

James,  H.  The  determination  of trace amounts of
cobalt  and  other  metals in  high  purity water using
ion-exchange membranes.  Analyst, 98, April 1973.

Martmola,  F.,  and G.  Kuhne.  Properties and
application of powdered  IX Resins. Internal Conf Ion
Exchange in Process Industries,  SCI, London, July
1969.

Naden, D.,  G.  Willey, and G.M. Newrick. The use of
fluid bed ion exchange lo reduce uranium  recovery
costs.  105  AIME  Annual  Meeting,  Las Vegas,
February 1970.

Naden,  D.  and M.R. Bandy. Choice and design of
solid ion  exchange plants for the recovery of uranium.
J Chem Tech Biotechnol, 29, 1979.

Nott, B.R. Eleclrodialytic decontamination of spent ion
exchange resins from CANDU  primary heat transport
purification  circuits. Paper, Internal  Sym Waler
Chemical  & Corrosion  Problems  Nucl  Reaclor
Systems &  Components, Vienna, November 1982.

Phillips,  B.A.,  E.W. Hooper, S.P. Dagnall, and N.P.
Monckton.  Study of Ihe behavior of inorganic  ion
exchangers in the  Ireatment of medium  active
effluents, Part  1:  preliminary  performance.  Atomic
Energy Research  Eslablishmenl (UK) G2872, 1984.

Ritcey,  G.M.,  M.J. Slater,  and B.H.  Lucas.  A
comparison  of  the processing  and  economics of
uranium  recovery from leach slurries by  continuous
ion exchange  and solvent  extraction.  120th  Internal
Symp on Hydrometallurgy,  Chicago, February 1976.

Rosembaun, J.B. and  J.R.  Ross. A counter-currenl
column for fluid bed ion exchange of uranium slurries.
Internal Symp  Hydromelallurgy. AIME, Chicago, 1973.
Physical Extraction

Screening
Allen,  T.  Parlicle  Size Measurement  2nd ed,
Chapman & Hall, 1974.

ANSI/ASTM E11-70. Standard specificalion for wire
clolh sieves for testing purposes.  In:  Annual Book of
ASTM Standards, 41, 1977.

Bandholz,  J.J. Horizontal screen  blinding  -  cause
and cures. Rock Prod, 72, February 1969.

Seven,  D.J.,  and  T.  Martyn. The  dry screening
cenlrifuge. Mine & Quarry, 1, May-June 1972.

Dehlen, B.L.A.  Rubber  in  vibrating  screens - an
efficienl weapon  against wear,  noise, and  dust.
Screening  Grading  Bulk  Materials.  Inst  Mech  Eng,
London, 1975.

Ephithite, H.J. The applications  of rubber  in  the
screening of bulk  materials.  Screening Grading Bulk
Materials. Inst Mech Eng, London,  1975.

Gluck,  S.E. Some technological factors affecting Ihe
economics of screening. J Mel, 18, March 1966.

Gluck,  S.E.  Vibraling  screens.  Chem  Eng,  75,
February 15, 1968.

Hoffman, C.W., and W.R. Hinken. Probability  sizing
- principles,  problems,  and  development  in  the
mining mduslry. Trans AIME/SME, 244,  June 1969.

Keller,  L.D. Fine screening:  Ihe current state  of the
art. AIME/SME  Preprint  71-8-25, AIME  1971.

Matthews,  C.W.  Screen  installations  to  meet
maintenance and  environmenlal  requiremenls. Rock
Prod, 73, April 1970.

Pnlchard, A.N. Choosing Ihe  righl vibraling screen.
Mine & Quarry, 9, December 1980.

Prilchard, A.N.  Vibraling  screens  in the  mining
industry. Mine & Quarry, 9, Oclober 1980.

Schulz, C.W., and R.B. Tippm.  Fundamentals  of
slalislical  screening.  Trans  AIME/SME,  247,
December 1970.

Shaw,  S.R. The rotating  probability  screen -  a new
concept in screening. Mine & Quarry, 12, October
 1983.

 Sullivan,  J.F.  Screening  technology handbook.
Tnple/S Dynamics, Inc., 1975.
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 Classification

 Bradley, D.  The  hydrocyclone.  Pergarnon  Press,
 Oxford, 1965.

 Edmiston,  K.J. International guide to hydrocyclones.
 World  Mining, 36, April 1983.

 Fitch,  E.B., and D.G.  Stevenson. Gravity separation
 equipment.  In:  solid/liquid  separation equipment
 scale-up.  Uplands Press, 1977.

 Heiskanen, K. Two stage classification. World Mining,
 32, June 1979.

 Kelsall,  D.F.,  and  J.C.H.  McAdam.  Design  and
 operating  characteristics  of  a  hydraulic  cyclone
 elutriator. Trans Inst Chem Eng, 41, 1963.

 Kelsall, D.F. The theory  and  applications of  the
 hydrocyclone. In: Solid/liquid separation; a review and
 bibliography.  (Ed. J.B. Poole and  D.  Doyle). HMSO,
 1966.

 Lynch, A.J. Mineral Crushing and Grinding.  Elsevier,
 Amsterdam, 1977.

 Trawmski,  H.  Theory, applications,  and   practical
 operation  of  hydrocyclone.   Eng  Mm   J,  177,
 September 1976.

 Wills,  B.A.  Factors  affecting  hydrocyclone
 performance. Min Mag, 142,  February 1980.


 Flotation

 Arbiter, N., C.C. Harris, and R. Yap.  Hydrodynamics
 of flotation cells. Trans AIME/SME, 244, 1969.

 Arbiter, N. and N. Weiss. Design of flotation cells and
 circuits. Trans AIME,  Vol 247, 1970.

 Arbiter, N. and C.C. Harris. Design  and Operating
 Characteristics  of  Large  Flotation  Cells. AIME/SME,
 Preprint, 79, 1979.

 Carnaham, T.G.,  and  K.P.V.  Lei.  Flotation  -  nitric
acid leach procedure for increasing uranium  recovery
from a refractory  ore.  U.S. Dept. of  the  Interior,
 Bureau of Mines, R.I. 8331, 1979.

Eccles, A.G.  In: Milling Practice in Canada,  (ed. D.E.
Pickett). CIM, 1978.

Ettelt,  G.A.  Activated  sludge  thickening  by
dissolved-air  flotation.  Indiana Waste Conf,  Purdue
Univ. 1964.
 Finkelstein,  N.P. and G.W.  Poling. The  role  of
 dithiolates in the flotation of sulphide minerals. Mineral
 Sci Eng 9, 1977.

 Flint, L.R. Factors influencing the design of  flotation
 equipment. Mineral Sci Eng, 5, 1973.
 Fuerstenau,  D.W.,  ed.  Froth  Flotation
 Anniversary Vol. AIME/SME, 1962
50th
 Fuerstenau, M.C., and W.F. Cummins.  The role  of
 basic  aqueous complexes  in  anionic  flotation  of
 quartz. Trans AIME/SME, 238, 1967.

 Fuerstenau,  M.C.,  ed. Flotation -  A.M.  Gaudin
 Memorial Volume, AIME/SME, 1976.

 Glembotskii,  V.A.,  V.I. Klassen,  and I.N.  Plaskin.
 Flotation, Primary Sources,  1963.

 Glembotskii,  V.A.,  V.I. Klassen,  and I.N.  Plaskin.
 Flotation. Primary Sources,  1972.

 Harris, G.H. Xanthates. In:  Encyclopedia  of Chemical
 Technology. 22, John Wiley, New York, 1970.

 Honeywell, W.R., and S. Kaiman. Flotation of uranium
 from  Elliot Lake ores. Dept of Mines  and  Tech.
 Surveys, Mines Branch, Canada, Reprint series  R S
 3, 1966.

 Klassen,  V.I. and V.A.  Mokrousov. An Introduction  to
 the Theory of Flotation. Butterworths,  1963.

 Klimpel,  R.R.   Selection of  chemical reagents  for
 flotation.  AIME/SME  Preprint  No 80-34, 1980.

 Kuhn,  A. Electroflotation - the technology and waste
 treatment applications.  Chem  Processing,  9, 6/74 and
 5, 7/74.

 Leja, J. Some  electrochemical  and chemical studies
 related to froth  flotation with xanthates.  Mineral Sci
 Eng, 5(J) 1973.

 Leja, J. Surface Chemistry of Froth Flotation. Plenum
 Press,  New York, 1982.

 Lynch, A.J., N.W. Johnson, E.V. Manlapig,  and C.G.
 Thome. Mineral and  Coal Flotation Circuits.  Elsevier,
 Amsterdam, 1981.

 Manser,  R.M.  Handbook of silicate flotation. Warren
 Spring  Lab, 1975.

 Palmer,  R.B.  et al.  Mechanisms involved  in  the
flotation of oxides and silicates with anionic collectors
Trans AIME/SME, 258,  1975.

Rulev,  N.N.   Theoretical   substantiation  of
experimentally  established  laws governing  the
                                                 109

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flotation of small particles,  (trans,)  Koll.  Zh. 40(6)
1978.

Sastry,  K.V.S., ed.  Agglomeration  77. AIME/SME,
1977.

Somasundavan, P., ed. Beneficiation of Mineral Fines.
AIME/SME, 1979.

Sorensen,  E.  On  the adsorption  of some  anionic
collectors  on fluoride minerals. J Coll Interface  Set;
45, 1973.

Trahar,  W.J. and J.L Warren. The Notability  of very
fine particles; a review. Internat J Mineral Processing,
3, 1976.

Trahar,  W.J.  A  rational interpretation of the  role of
particle  size in flotation. Internat J Mineral Processing,
8, 1981.

Wyman,  R.A.  The  floatability  of  twenty-one
nonmetallic minerals. Canadian Mines Branch, Tech
Bull TB108, 1969 .

Gravity Concentration
Apian,  F.F.  The state of the art  and the future of
gravity concentration. In: Research  Needs in  Mineral
Processing,  (ed.  P.  Somasundarian, and D.W.
Fuerstenau). Nat Sci Found,  New York, 1975.

Batzer,  D.J. Investigation into jig performance. Trans
IMM, 72,   1962-63.

Burt, R.O. A study of the effect  of deck surface and
pulp  pH  on  the  performance of  a  fine  gravity
concentrator. Internat J Mineral Processing, 5, 1978.

Kirchberg, H.  and  W. Berger. Study of  the operation
of shaking concentration tables.  Paper 25,  Internat
Mineral Processing Congr, London, 1960.

Mayer,  F.W. Fundamentals of a potential theory of the
jigging  process.  Proc 7th  Internat Mineral Processing
Congr,  Vol I, Gordon and Breach, New York, 1965.

Michell, F.B. Table flotation.  Mineral Mag, 73,  1945.

Michell, F.B. and D.G. Osborne. Gravity concentration
in modern mineral processing. Chem Ind, 58, 1975.

Muller,  L.D., C.P. Sayles, and R.H. Mozley. A pulsed
deck   gravity  concentrator  and  comparative
performance analysis. Vol I,  Proc. 7th Internat Mineral
Processing Congr, New York,  1964

Nair, J.S.,  S.N. Degaleeson, and  K.K.  Majumdar.
Automatic splitter for wet tabling of  radioactive ores.
Trans Inst Minerals and Metals, 83, 1974.
Ottley, D.J. Technical, economic and other factors in
the gravity concentration of tin, tungsten, columbium,
and tantalum ores. Minerals Sci Eng, 11, April 1979.

Rao, S.R. and L.L. Sirois. Study of surface chemical
characteristics in gravity  separation.  CIM  Bull,  67,
June 1974.

Richards, R.H., and S.B. Locke.  Textbook  of mineral
dressing. McGraw-Hill,  New York, 1940.

Terrill,  I.J.,  and J.B.  Villar.  Elements  of  High-
Capacity Gravity Separation. CIM Bull, 68, May 1975.

Terry,  R.L.  Minerals concentration  by  wet tabling.
Mineral Processing, 15, July-August  1974.

Tiernon, C.H.  Concentrating tables for  fine  coal
cleaning. Mining  Eng, 32, August 1980.

Welsh,  R.  and A.  Deurbrouck.   Photo-electric
concentrator for the wet concentrating table. U.S.B.M.
Rep on Investigations 7623, 1972.

Wiard,  E.S.  Theory  and  practice of ore  dressing.
McGraw-Hill,  New  York,  1915.


Sedimentation
Adorjan, L.A.  A Theory of sediment  compression.
Proc 11th Internat  Min  Process Congr, Univ Caglian,
1975.

Coe,   H.S.  and G.H.  Clevenger.  Methods for
determining  the capacities  of  slime  settling tanks.
Trans AIME TMS. 55, 1916.

Emmett, R.C.  and R.P.  Klepper. Technology  and
performance  of the hi-capacity thickener,  Mining
Eng, 32, August 1980.

Fitch,  E.B. and  D.G.  Stevenson. Gravity  separation
equipment.  In:  Solid/Liquid  Separation Equipment
Scale-Up, Upland  Press,  1977.

Keane, J.M.  Sedimentation:  theory,  equipment, and
methods. World  Mining, 32, November 1979.

Keane, J.M.  Recent  developments  in solids/liquid
separation. World Mining, 110, October 1982.

Robins, W.H.M. The  theory  of the  design  and
operation of settling tanks. Trans Inst  Chem Eng,  42,
1964.

Scott, K.J. Theory of Thickening. Trans IMM(C),  77,
June 1968.
                                                  110

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 Filtration

 Adamson, G.F.S. Some recent papers on flocculation.
 Mine & Quarry, 10, March 1981.

 Akers,  R. Flocculation. I Chem E Services, London,
 1975.

 Clement,  M. and  J. Bonjer. Investigation on  mineral
 surfaces for improving the dewatenng of slimes with
 polymer flocculants. Proc  11th Internal Mm Process
 Congr,  Univ Cagliari, 1975.

 Dahlstrom,  D.A.  and  C.E.  Silverblatt. Continuous
 vacuum and pressure  filtration.  In:  Solid/Liquid
 Separation  Equipment Scale-Up  (ed.  D.  Purchas),
 Uplands Press, 1977.

 Daykin, K.W. et al. Steam-assisted vacuum filtration.
 Mine & Quarry, 7,  March 1978.

 Dexter, R.H.  and  D.G.  Osborne.  Principles  of the
 selective flocculation of minerals from mixtures  using
 high molecular weight polyelectrolytes. J Camborne
 Sch Mines,  73, 1973.

 Gregory, J.  In: The Scientific Basis  of Filtration, (ed.
 K.J. Ives), Noordhoff, Leyden, 1975.

 Hunter, T.K. and  M.J.  Pearse.  The use of flocculants
 and surfactants  for  dewatering  in  the  mineral
 processing  industry. Proc  IVth  Internal Min Process
 Congr,  Paper IX-11, CIM, Toronto, October  1982.

 Lightfoot, J. Practical aspects of flocculation.  Mine  &
 Quarry, 10, April 1981.

 Moss, N. Theory  of flocculation. Mine & Quarry, 7,
 May 1978.

 Paananen,  A.D.,  and  W.A.  Turcotte.  Factors
 influencing slective flocculation-desliming  practice at
 the Tilden Mine. Min Eng, 32, August 1980.

 Purchas, D.B.  Filter  media,  a survey. Filtr.  Sept.
 1965.

 Purchas, D.B. Industrial  filtration of  liquids. Leonard
 Hill Books, London, 1971.

 Read,  A.D., and  G.T.  Hollick.  Selective flocculation.
 Mine &  Quarry, 9, April 1980.

 Silverblatt,  C.E.,  H. Risbud,  and F.M.  Tiller.  Batch,
continuous processes for cake  filtration. Chem  Eng,
81, April 29, 1974.
                                                  111

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                                  Abbreviations and Symbols
AEC
ATSDR
CDC
CERCLA

Ci
cm
cu ft
cu m
cu yd
DOE
EPA/USEPA
FS
ft
FUSRAP
9
hr
kg
kg/hr
kW
MED
jim
mm
NJDEP
NRC
NPL
ORNL
pCi
pCi/g
pCi/l
Rl
RI/FS
SARA
sq ft
sq m
sq yd
UMTRAP
uR
USGS
WL
U. S. Atomic Energy Commission
Agency for Toxic Substances and Disease Registry
Centers for Disease Control
Comprehensive Environmental Response,  Compensation, and Liability  Act  of I960
(Superfund)
Curie
Centimeter  (10-3 meter)
Cubic foot
Cubic meter
Cubic yard
Department of Energy
U. S. Environmental Protection Agency
Feasibility Study
Foot or feet
Formerly Utilized Sites Remedial Action Program (Department of Energy)
Gram
Hour
Kilogram (1000 grams)
Kilograms per hour
Kilowatt (1000 watts)
U. S. Army Corps of Engineers, Manhattan Engineering District
Micron (micrometer, 10-6  meter)
Millimeter (10-3 meter)
New Jersey Department of Environmental Protection
Nuclear Regulatory  Commission
National Priorities List
Oak Ridge National  Laboratory
Picocurie (10'12  Curie)
Picocuries per gram
Picocunes per liter
Remedial Investigation
Remedial Investigation/Feasibility Study
Superfund Amendments and Reauthorization Act of I986
Square foot
Square meter
Square yard
Uranium Mill Tailings Remedial Action Project (Department of Energy)
Microroentgen (10~6 roentgen)
U. S. Geological Survey
Working level
                                                112

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Convers/ons
To Convert From (A)
acre
cu ft
cu yd
F
ft
kW
mile
sq ft
tons
C
Curies
meter
kg
mg/l
atmosphere (atm)
To(B)
hectare
cu m
cu m
C
m
kg-calones/min
meters
sq m
kg
F
disintegrations per minute
yd
Ib
parts per million
kilo Pascal (kPa)
Multiply (A)
0.4047
0.02832
0.7646
.BY



(F-32)x5/9
0.3048
1.434
1609
0.0929
1016
(Cxg/5) 
2.2 x 1012
1.094
2.2046
1.0
101





 32





    113

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Key
Name
Actinium
Aluminum
Arsenic
Barium
Beryllium
Bismuth
Boron
Bromine
Cadmium
Calcium
Carbon
Chlorine
Chromium
Cobalt
Copper
Fluorine
Helium
Hydrogen
Iodine
Iron
Lead
Lithium
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Niobium
Nitrogen
Oxygen
Palladium
Phosphorus
Platinum
Plutonium
Polonium
Potassium
Radium
Radon
Selenium
Silicon
Sodium
Strontium
Sulfur
Thorium
Tin
Titanium
Tungsten
Uranium
Vanadium
Zinc
Chemical Elements
Abbreviation
Ac
Al
As
Ba
Be
Bi
B
Br
Cd
Ca
C
Cl
Cr
Co
Cu
F
He
H
1
Fe
Pb
Li
Mg
Mn
Hg
Mo
Ni
Nb
N
0
Pd
P
Pt
Pe
Po
K
Ra
Rn
Se
Si
Na
Sr
S
Th
Sn
Ti
W
U
V
Zn
114

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                                               Glossary
Air Avid

Alpha particle




Alpha radiation
Background
radiation
Ball decks


Beneficiation

Beta particle


Beta radiation


Blinding

Detection level


Dose Equivalent




Entry routes


Exfiltration

External
radiation

Gamma
radiation


Grizzly screen

ground water

Half-life


Indoor air
To increase by addition of chemicals the affinity of fine particles for air bubbles.

A  positively-charged  subatomic  particle  emitted  during decay  of  certain  radioactive
elements.  For  example,  an  alpha particle  is  released when  radon-222  decays to
polonium-218. An alpha  particle  is  indistinguishable  from a helium  atom nucleus  and
consists of two protons and two neutrons.

The least  penetrating  type of radiation. Alpha radiation can be stopped  by a sheet of paper
or outer dead layer of skin.

The  radioactivity  in the  environment,  including cosmic rays from space  and  radiation
that exists elsewhere - in the  air,  in the earth, and  in  man-made materials. In the  U.S.,
most people receive 100 to 250 millirems of background radiation per year.

A tray  of rubber balls that bounce against the bottom surface of a screen, thus eliminating
blinding.

Preparation of ore for  smelting

A  negatively-charged  subatomic  particle  emitted during decay  of  certain  radioactive
elements. A beta particle is identical to an electron.

Emitted from a nucleus during fission. Beta radiation can be stopped by an inch of wood or
a thin sheet of aluminum.

Plugging of the screen apertures with slightly oversized particles.

The minimum concentration of a substance that can be measured with a 99%  confidence
that the analytical concentration is greater than zero.

The product of the absorbed dose, the quality factor, and any other modifying factors. The
dose equivalent  is a quantity for comparing the biological effectiveness of different kinds of
radiation on a common scale. The  unit of dose  equivalent is  the rem. A millirem (mrem) is
one one-thousandth of a rem.

Pathways by which soil gas can flow into a house.  Openings through the flooring and walls
where  the house contacts the soil.

The movement of indoor air out of the house.

Radiation  originating from a source outside the body, such as cosmic radiation. The source
of external radiation can be either natural or  man-made.

A  form of electromagnetic, high-energy radiation emitted from a nucleus. Gamma rays are
essentially the same as  x-rays and require heavy  shieldmgs,  such as concrete  or steel, to
be stopped.

Screen made of heavy fixed bars, used to remove oversized stones, tree stumps, etc.

Subsurface water that is  in the pore spaces of soil and geologic units.

The  length of time in which any radioactive substance will  lose  one-half its radioactivity.
The half-life may vary in length from a fraction of a second to thousands of years.

That air that occupies the space within the interior of a house or other building.
                                                   115

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Ion exchange
Internal
radiation

Isotopes
Mesh

Microrem(pR)

Microrem per
hour (uR/hr)

Millirem (mrem)

NARM



ORNL

Picocurie (pCi)
Picocurie per
 liter (pCi/l)
Plutonium



Radiation



Radioactivity


Radionuclide

Radon
Radon progeny,
Radon daughter
REM
Revolving Screen
The reversible exchange of ions contained in a crystal for different ions in solution, without
destroying the crystal structure or disturbing the electrical neutrality.

Radiation originating from a source within the body as a result of the inhalation, ingestion, or
implantation of natural or man-made radionuclides in body tissues.

Different forms of the  same chemical element that are distinguished  by  having  different
numbers of neutrons in the nucleus. A  single element may have many  isotopes. For
example, the three isotopes of hydrogen are protium, deuterium, and tritium.

Number of wires per inch in a screen.

A unit of radiation "dose equivalent" that is equal to one one-millionth of a rem.

A unit of measure of the rate at which "dose equivalent" is being incurred  as  a  result of
exposure to radiation.

A unit of radiation "dose equivalent" that is equal to one one-thousandth of a rem.

Naturally-occurring or  accelerator-produced radioactive  materials mean  any  radioactive
material except for material classified  as source, by-products, or special nuclear material
under the Atomic  Energy Act of 1954, as  amended.

Oak Ridge National Laboratory

A unit of measurement of radioactivity.  A curie is the amount  of any radionuclide that
undergoes  exactly 3.7  x 1010  radioactive  disintegrations per second.  A  picocurie is one
trillionth (1012) of  a curie, or 0.037 disintegrations per second.


A common unit of measurement of the concentration of radioactivity in a gas or  liquid. A
picocurie per liter  corresponds to 0.037 radioactive disintegrations  per second  in every  liter.

A heavy, radioactive, man-made metallic element. Its  most important isotope is fissionable
238pU! which  is produced  by the irradiation of  238(j.  Routine analysis cannot  distinguish
between the 239pu and  240pu isotopes, hence,  the term 239,240pu.

Refers to the process of emitting energy  in the  form of rays or particles that are thrown off
by disintegrating atoms. The rays or particles emitted may consist of alpha, beta, or gamma
radiation.

A property possessed by some  elements, such  as uranium, whereby alpha,  beta, or gamma
rays are spontaneously emitted.

Any naturally occurring or artificially produced radioactive element or isotope.

A  colorless, odorless,  naturally occurring,  radioactive  gaseous  element  formed  by
radioactive decay  of radium  atoms. Chemical  symbol is Rn, atomic weight 222, half-life
3.82 days.

A term  used to refer collectively  to the intermediate products in the radon decay chain.
Each  "daughter"  is  an ultrafine radioactive particle that decays into  another  radioactive
"daughter" until finally a stable nonradioactive  molecule of lead  is formed and no further
radioactivity is produced.

An acronym for Roentgen  Equivalent Man; a unit of  radiation exposure that indicates the
potential impact on human cells.

A screen with a surface that revolves around an axis; the screen surface may be inclined or
vertical.
                                                  116

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Rotary sifter

Scalping

Shaking screens


Sieve bends


Soil gas




Tailings


Uranium




Vibrating screen
Working level
(WL)
Circular motion applied to a rectangular or circular screen surface.

Removal of small amounts of oversized material from feed.

Several screen surfaces in a series, usually slightly inclined,  with different apertures and a
slow linear motion essentially in place of the screen.

Screens with stationary parallel bars at a right angle to the feed flow;  the surface may be
straight, with a steep incline, or curved to 300.

Those gaseous elements and compounds that occur in the small spaces between particles
of the earth or soil. Rock can contain gas also.  Such gases can move through or leave the
soil or rock depending on  changes in pressure. Radon is  a gas that forms in  the soil
wherever radioactive decay of radium occurs.

Sand-like waste resulting from  uranium production, represents about 98% of the ore that
enters the mill.

A naturally radioactive element with the atomic number of 92 (number of protons in nucleus)
and an atomic weight of approximately  238. The two principal  naturally occurring isotopes
are the  fissionable  U-235  (0.7% of natural uranium)  and  the  fertile U-238 (99.3% of
natural uranium).

An inclined or horizontal rectangular screening  surface with a high-speed vibrating  motion
that lifts particles  off the surface.

A unit of measure of the exposure rate to radon  and radon progeny defined as the quantity
of short-lived  progeny that will result in 1.3 x  1Q.5 MeV of potential  alpha energy per liter of
air. Exposures are measured in working level months (WLM);  e.g., an exposure to 1  WL for
1 working month  (173 hours) is 1 WLM. These units were developed originally to measure
cumulative work place exposure of underground uranium  miners to radon and continue to
be used today as a  measurement  of human exposure to radon and radon progeny.
                                                                     US GOVERNMENT PRINTING OFFICE 1988-548-158/87027
                                                  117

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