Office of Research and Development
Industrial Environmental Research FP A-fiOD/7-7fi-n'3fi
Laboratory
Cincinnati,Ohio 45268     December 1976
      ASSESSMENT OF
      ENVIRONMENTAL ASPECTS OF
      URANIUM  MINING AND  MILLING
      Interagency
      Energy-Environment
      Research and Development
      Program Report

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                       RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S.
Environmental Protection Agency, have been grouped into seven series.
These seven broad categories were established to facilitate further
development and application of environmental technology.  Elimination
of traditional grouping was consciously planned to foster technology
transfer and a maximum interface in related fields.  The seven series
are:

     1.  Environmental Health Effects Research
     2.  Environmental Protection Technology
     3.  Ecological Research
     4.  Environmental Monitoring
     5.  Socioeconomic Environmental Studies
     6.  Scientific and Technical Assessment Reports (STAR)
     7.  Interagency Energy-Environment Research and Development

This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series.  Reports in this series result from
the effort funded under the 17-agency Federal Energy/Environment
Research and Development Program.  These studies relate to EPA's
mission to protect the public health and welfare from adverse effects
of pollutants associated with energy systems.  The goal of the Program
is to assure the rapid development of domestic energy supplies in an
environmentally—compatible manner by providing the necessary
environmental data and control technology.  Investigations include
analyses of the transport of energy-related pollutants and their health
and ecological effects; assessments of, and development of, control
technologies for energy systems; and integrated assessments of a wide
range of energy-related environmental issues.
This document is available to the public through the National Technical
Information Service, Springfield, Virginia  22161.

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                                             EPA-600/7-76-036
                                             December 1976
    ASSESSMENT OF ENVIRONMENTAL ASPECTS
       OF URANIUM MINING AND MILLING
                     by
   A. K. Reed, H. C. Meeks,  S.  E.  Pomeroy,
               and V. Q. Hale

                  Battelle
           Columbus Laboratories
           Columbus, Ohio  43201
          Contract No. 68-02-1323
                  Task 51
              Project Officer

              Elmore C. Grim
 Resource Extraction and Handling Division
Industrial Environmental Research Laboratory
          Cincinnati, Ohio  45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
    OFFICE OF RESEARCH AND DEVELOPMENT
   U.S. ENVIRONMENTAL PROTECTION AGENCY
          CINCINNATI, OHIO  45268

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                                  DISCLAIMER
     This report has been reviewed by the Industrial Environmental Research
Laboratory, U. S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and
policies of the U. S. Environmental Protection Agency, nor does mention of trade
names or commercial products constitute endorsement or recommendation for use.
                                     ii

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                              FOREWORD
     When energy and material resources are extracted, processed,
converted, and used, the related pollutional impacts on our
environment and even on our health often require that new and
increasingly more efficient pollution control methods be used.
The Industrial Environmental Research Laboratory - Cincinnati
(lERL-Ci) assists in developing and demonstrating new and
improved methodologies that will meet these needs both efficiently
and economically.

     In this report a preliminary assessment was made of the
potential environmental impacts associated with the mining and
milling of domestic uranium ores.  All forms of pollution except
radiation were considered.

     It was concluded that the impacts identified were not
believed to be of immediate concern but rather are potential
problems which may arise in the long term.  Future environmental
studies should consider tailings pond disposal, deep well injection
to.dispose of toxic wastes and reclamation of spoils.

     Results of this work will be of interest to State and Federal
agencies and mining firms who are interested in assessing and
controlling the environmental impacts of uranium mining and
milling.

     For further information contact the Resource Extraction and
Handling Division.
                                  David G. Stephan
                                     Director
                     Industrial Environmental Research Laboratory
                                    Cincinnati
                                 ill

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                                    ABSTRACT
      This research program was initiated with  the  basic objective of making a
 preliminary assessment of the potential environmental  impacts associated with
 the mining and milling of domestic  uranium ores.   All  forms of pollution
 except radiation were considered.

      The program included a review  of  the characteristics and locations of
 domestic uranium ore reserves and a review of  the  conventional methods for
 mining and milling these  ores.   Potential environmental impacts associated
 with the entire cycle from exploration and mining  to recovery and production
 of  yellowcake  are identified and discussed.  Land  reclamation aspects are also
 discussed.

      The methods  currently used  for production of  yellowcake were divided into
 four  categories - open pit mining-acid  leach process, underground mining-acid
 leach process,  underground mining-alkaline leach process, and in-situ mining.
 These are discussed  from  the  standpoint of  typical active mills which were
 visited  during  the program.   Flowsheets showing specific environmental impacts
 for each category are  provided.

      It  was generally  concluded  that the  use of tailings ponds and deep well
 injection to dispose of the more toxic chemical wastes represent the major
 impacts which should be considered  in future environmental studies.

     This report was submitted in fulfillment of Contract No.  68-02-1323 by
Battelle, Columbus Laboratories, under sponsorship of the U.  S.  Environmental
Protection Agency.  This report covers the period February 12,  1976, to July
7, 1976, and work was completed as of September 30, 1976.
                                      xv

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                               TABLE OF CONTENTS
Foreword	
Abstract	      iv
Figures	- .     vii
Tables	     vii

   1.  Introduction	       1
   2.  Conclusions 	       2
   3.  Uranium Resources in the United States  	       4
          Types of Uranium Deposits  	       4
             Deposits in the Rocky Mountain Region 	       5
             Sandstone Deposits  ........  	       5
             Vein Deposits	       7
             By-Product Uranium From Copper Leach Solution 	       8
             By-Product Uranium From Phosphoric Acid Production  .  .       8
             Other Unconventional Deposits 	       9
          Location of Active Mills 	       9
   4.  Mining and Recovery Processes 	      13
          Conventional Mining Operations 	      13
             Surface Mining  	      13
             Underground Mining  	      15
             In-Situ and Heap Leaching	      16
          Conventional Recovery Processes  	      16
             Ore Preparation	      16
             Acid Leaching	      17
             Carbonate Leaching  	      17
             Liquid-Solids Separation  	      18
             Solution Purification and Concentration 	      18
             Product Precipitation 	      19
             Yellowcake Drying 	      20
   5.  Potential Environmental Impacts 	      21
          Exploration	      21
             Air	      21
             Liquids	      21
             Land Surface	      22
          General Impacts From Mining  	      22
             Fugitive Dust	      22
             Vehicle Emissions 	      23
             Mine Water	      23
             Solids	      27
          General Impacts From Milling	~ -	      28
             Dust  	      28
             Chemicals	      28
             Liquids	      28
             Solids	      33

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                               TABLE OF CONTENTS
                                  (Continued)
            Specific  Impacts From Typical Mining-Milling
             Operations	     34
              Open Pit-Acid Leach Process  	     34
             Underground Mine-Acid Leach Process  	      37
             Underground Mining-Alkaline Leach Process 	      39
             Ih-Situ Mining Process   	      40
   6.  Reclamation	      44
          Disturbed  Areas  	      44
             Spoils	      44
             Final Mining Pit	      46
             Tailing Ponds 	      46
          Stabilization  	      47
             Spoils	      47
             Tailings	      47
          Revegetation 	      47

References	      49
                                      vi

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                                    FIGURES

Number                                                                  Page

   1      Uranium Reserve Regions, Western United States  	       6

   2      Location of Active Uranium Mills in the United
            States	      12

   3      Uranium Extraction Flowsheet, Open Pit-Acid Leach
            Process	      36

   4      Uranium Extraction Flowsheet, Underground Mine-Acid
            Leach Process	      38

   5      Uranium Extraction Flowsheet, Underground
            Mine-Alkaline Leach Process  	      41

   6      Uranium Extraction Flowsheet, In-Situ Mining
            Process	      43


                                    TABLES

   1      Types of Uranium Deposits  	      10
                                                                •
   2      Active Uranium Mills in the United States and Ore
            Characteristics  	      11

   3      Estimated Air Pollutant Emissions From Earth Hauling
            Equipment at a 1350 Mt/Day Underground Mine	      24

   4      Estimated Air Pollutant Emissions From Earth Hauling
            Equipment at a 1350 Mt/Day Surface Mine	      24

   5      Composition of Discharge Water From Mines  	      25

   6      Composition of Discharge Water From Underground Mines  .  .      26

   7      Chemicals Used in Milling Operations .  T	      30

   8      Trace Elements Leached From Ore by Milling Process ....      31

   9      Analysis of an Alkaline Leach Mill Tailings Effluent ...      31

  10      Process Variations Used by Active Uranium Plants 	      35
                                   vii

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                                   SECTION 1

                                 INTRODUCTION
     Uranium is an important energy source for which projected demands will
greatly increase in the near future.  Identified exploitable uranium deposits
in the United States are mostly in sandstones and related rocks and the
principal known deposits are in Wyoming, the Colorado River Plateau, and the
Texas Gulf Coast.

     Uranium occurs as coatings on sand grains or as filling or cement in
interstitial spaces where it has accumulated by water deposition.  Because of
this, the uranium content of the ore is on the order of 0.2 to 0.3 percent
U30s-  Thus, large amounts of material must be handled in mining and initial
processing operations.  Some deposits are at depths which require underground
mining but surface mining is a more economical method where it can be used.

     Primary processing facilities are located near the mines to reduce haul-
ing costs.  Uranium from the ore is typically recovered by alkaline or acid
Leaching depending upon the nature of the ore.  Solvent extraction and the use
of ion exchange resins are important variations in concentrating the uranium
values which are then precipitated to form yellowcake (85-95 percent
     The scope of this investigation thus was to identify the steps involved
from mining of ore to output of yellowcake, evaluate alternative processing
methods, and assess the potential environmental impacts associated with each
operation.

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                                   SECTION 2

                                  CONCLUSIONS
     Several potentially significant, environmental impacts have been identi-
fied based on this preliminary survey of the domestic uranium industry.   The
impacts identified, however, are not believed to be of immediate concern but
rather are potential problems which may arise in the long term.   Following  is
a summary of the impacts believed to be of major significance.

     (1)  Tailings Pond Disposal.  It is currently estimated that
          over 9 million metric tons of tailings per year are
          disposed of to tailings ponds by the domestic  uranium
          industry.  In addition, an equal or greater amount of
          waste milling solutions are also disposed of to the
          ponds.  The liquid portions contain various heavy
          metals as well as being highly acid or alkaline depending
          on the type of mill generating the waste.

               The use of a tailings pond represents only a tempo-
          rary solution to the potential environmental problems
          which could be caused by these wastes.   Methods are needed
          to  stabilize this material and reclaim the tailings areas.
          Greater  information is also needed on  the movement and
          amount of contaminants that enter  ground and surface waters
          through  percolation and seepage from the tailings ponds.
          Studies  in New Mexico,  for example,  show that  tailings
          pond  seepage can result in ground  water  contamination by
          selenium;  contamination by other substances  may also
          have  occurred.

     (2)   Deep Well  Injection.   Several  uranium mills  dispose of
          toxic  liquid  and  chemical  wastes by  deep well  injection.
          The wastes  result  either from  excess liquid  not  evaporated
          in the tailings  pond  or from waste regenerant  solutions
          used by  in-situ mining  operations.  Very little  is  known
          about  the overall  long-term impacts on ground waters due
          to deep well  injection.

              A similar  though different  impact can occur  in those
          plants using  in-situ mining  in  that a loss of leaching
          solution pumped  into  the ore body via wells  could  contami-
         nate local groundwaters.   This aspect of the overall industry
         needs to be closely monitored so that if a problem  does
         arise the overall  impact can be minimized.

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(3)   Reclamation.   Some research has  been  initiated  in  recent years
     on reclamation of spoils,  especially  in  coal mining  operations,
     but also at uranium mines.   This research  is directed  almost
     entirely to soil and water management.   Additional areas of
     research which are needed  are the development of plant species
     that are adapted to reclamation  needs and  to development of
     alternative uses of disturbed lands which  cannot be  restored
     to their premine condition.

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                                    SECTION 3

                     URANIUM RESOURCES IN THE UNITED STATES
      A preliminary survey of the geologic deposition and mineralization of
 uranium resources has been conducted and is presented in this section.   This
 survey is based on a review of the literature and information obtained  from
 government agencies and industry.  Some engineering judgments were applied  to
 quantify resource estimates where data did not exist or were poorly defined.

      The terms "reserves" and "resources" need to be clarified before a dis-
 cussion of mineral supply can be meaningful.   They are not  interchangeable
 and require careful definition.

      Reserves are that quantity of ore minerals in identified deposits  that
 can be developed at current levels of technology and costs.

      Resources (whether concentrated or dilute)  are fixed in limit  by the
 composition of the earth's crust, seas, and atmosphere.   Some resources can
 become reserves at higher costs  and as such are most often  "implied reserves"
 extrapolated from generalized data.

      To  evaluate the  supply of uranium,  resources must  be continuously
 reassessed  in terms of new geologic  knowledge  and changes in technology.

 TYPES OF URANIUM DEPOSITS

      Uranium minerals  are  known  to occur  almost  everywhere  in the earth's
 crust which  contains a mean abundance  of  about  2  ppm uranium.  However,  the
 larger concentrations  of uranium  which make up  the ore reserves are  located
 only  in a few well-defined areas  in  the world.  For  example,  about  30 percent
 of the world's  reported uranium reserves  are found  in the Rocky Mountain area
 of the United States.^'   The uranium  is  found in  rather small areas in which
 a few large  or many small  ore deposits of differing mineralization occur.

     Uranium  is  found in a wide variety of locations.  This gross variety is
 considered the result of uranium's (1) physical properties,  particularly its
 polyvalency,  (2) large atomic radius,  (3) high chemical reactivity,  (4)  rela-
 tive  solubility of many of its hexavalent compounds  in aqueous solutions, and
 (5) its relative abundance.  Consequently, virtually no geologic environment
 can be considered totally  free of uranium, although certain habitats
are favored.

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      Deposits of potential economic importance first were identified at the
 Wood  Mine  in Colorado in a vein deposit.  In 1898 the deposits in sandstone
 were  discovered.   Subsequently the Rocky Mountain region became the principal
 domestic source of uranium.  It is estimated that this region contains about
 90  percent of the U. S. reserves.(D  The uranium reserve regions of the
 western United States with production areas and areas with reserves greater
 than  500 tons I^Os are shown in Figure 1.  In view of these data, the Rocky
 Mountain region then must be considered as the prime source for the future
 use of uranium in  the U. S. for at least several decades.

 Deposits in the Rocky Mountain Region

      The overall Rocky Mountain area in the United States has been identified
 as  a  uranium metallogenic province.  This constitutes a broad, indefinitely
 defined region centering on the curr'ent Rocky Mountains and in which an ini-
 tial  concentration of uranium may have occurred.  Subsequent to this concen-
 tration in early Precambrian time, the uranium was redistributed, reworked,
 and reconcentrated by many igneous, sedimentary, and metamorphic processes.
 The currently exploitable deposits are the results of that reworking.

      In the Rocky Mountain region, 98 percent of the U^Og recovered has come
 from  sandstones and related rocks.  Estimates of known reserves in those rocks
 were more  than 95 percent of the total reserves in 1958, and 97 percent in
 1974.' '   There are probably comparable amounts of undiscovered, commercial-
 grade uranium present there also.  About 70 percent of the domestic production
 of  U30s has come from the Colorado Plateau part of the Rocky Mountains.  An
 evaluation of the potential U30g reserves and resources of the United States
 should first consider the possibilities in comparable areas in the Colorado
 Plateau and adjoining districts, especially at depth, rather than that large
 high-grade  deposits might be expected in other areas in the United States.

 Sandstone Deposits

     Most  of the uranium deposits of the Colorado Plateau and adjoining
 districts  occur in frequently predictable stream-laid lenses of sandstone,
 dominantly  in the Chinle, Shinarump, and Morrison Formations.  Uranium de-
 posits also occur in sediments in the Wind River Formation in Gas Hills and
 Shirley Basin areas, Wyoming and in other formations of lesser importance
 elsewhere.   These deposits also are known as the peneconcordant deposits, and
 constitute by far the bulk of the "conventional" deposits.  The uranium ore
bodies traditionally form tabular or lenticular layers (pods) that are nearly
 concordant  (parallel) to the bedding.  Locally they deviate from it, espe-
 cially in  detail.  In many deposits the elongate pods have the transverse
 cross-section form of an erect crescent and are referred to as rolls.  They
 thus differ in form and origin from classical sedimentary (bedded) deposits
of other minerals that closely and consistently follow the bedding.  The
occurrences of ore in the truly bedded deposits often can be predicted.

     The ore bodies vary greatly in size, from those containing only a few
tons to those hundreds of meters across and containing millions of tons of
ore.  Some deposits are thousands of meters long.  In the Shirley Basin and

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        SPOKANE,
                               POWDER
                                RIVER

                      R.VERTON,^
                       •   U—>>'~^*
                      GAS HILLS
                     CROOKS GAP,
                      MAYBELL
                                      ^BELFIELD

                                          CAVE HILLS
                                          SLIM BUTTES
                                       BLACK HILLS |
                                           •EDGEMONT
        GREEN RIVER

      SAN RAFAEL

MARYSVALE



 WHITE CANYON
                                            GRAND JUNCTION
                                  CASP|R_ SHIRLEY

                                  FRONT"" BASIN

                                  RAN£LLrDENVER
                          LISBON MARSHALL   URAVAN
                          VALLEY~PASSr-L	MINERAL
                          •^                 BELT
                                   GRANTS
                                  MINERAL
                                    BELT
                 MONUMEN1
                  VALLEY
              KENDRICKBAY
                AREAS WITH PRODUCTION AND $35.00 RESERVES
                GREATER THAN 500 TONS U30g  (NAMES SHOWN)

                OTHER AREAS WITH PRODUCTION AND $35.00
                RESERVES GREATER THAN 10 TONS U308
           Source:  AEC, Grand  Junction. CO
FIGURE 1.  URANIUM RESERVE  REGIONS,  WESTERN UNITED STATES

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 the  southern part of the Powder River Basin, Wyoming, and in the Ambrosia
 Lake District, New Mexico, groups of ore bodies and the intervening thinner
 mineralized zones extend intermittently from 8 to 10 kilometers.^'

     Within many metal deposits other than uranium, low-grade ores commonly
 form a mineralized halo, centered around the higher grade ores.  However, for
 uranium deposits, the edges of the peneconcordant ore bodies terminate
 abruptly with no large halo of low-grade ore.

     The specific sources of uranium, precise flow paths, specific and local
 causes of ore deposition, and the ages of the deposits are somewhat uncertain
 and  may vary significantly from deposit to deposit.  In general the ore was
 formed by ground-water solutions that moved downdip by gravity to a reducing
 environment where the uranium was precipitated.  The uranium probably was
 deposited and reworked by various processes, including weathering in some
 instances as a final process.  The primary source and controls to initial ore
 deposition often are obscure.  Although guides to prospecting are available
 and  helpful, most uranium deposits are discovered in their outcrops, and the
 mineralization is traced by exploration, including drilling.  This is
 especially the case in the more irregular deposits.

     The depth of favorable stratigraphic units is probably not critical to
 the  occurrence of uranium deposits.  Some deposits have been discovered at
 depths between 700 and 1200 meters.  Certainly more can be expected to be
 found.  Once the incentive exists for exploration to those greater depths and
 once targets are identified, more such discoveries can be expected.  Butler
 concluded that at least 300 million tons of ore-grade rock and probably as
 much as one billion tons may occur in sandstones in the United States.  Much
 of the larger amount, if actually present, is overlain by at least 600 meters
 of rock and will be difficult to find and exploit.  Most of the occurrences
 may  be expected in the western part of the United States and probably in the
 Rocky Mountain area.

 Vein Deposits

     Vein deposits, including true veins, aggregates of veinlets, and miner-
 alized breccia ("collapsed") pipes also are categorized as "conventional"
 deposits, together with the sandstone occurrences.  They are widely distrib-
 uted throughout much of the United States.  With few exceptions, however,
 the vein deposits represent small reserves and production.

     Vein deposits that have produced uranium occur throughout the Rocky
Mountain region, especially in Colorado and Utah, and in northeastern
 Washington, western and northern Idaho, southeastern- Oregon, the Great Basin
 of Nevada, southern California and Alaska.  They are generally-small.  For
 example, five of the largest deposits in the Rocky Mountain region originally
 contained as much as 100,000 tons of ore.  However, all vein deposits com-
 bined have yielded 1,644,000 tons or about 2.5 percent of the total ore pro-
 duced in the Rocky Mountain region.  The Marysvale, Utah, deposit, together
with those of the Schwartzwalder Mine in Colorado, and the Midnite Mine in
 northeastern Washington are the largest vein deposits in the United States.

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      The downward extent of uranium in the vein deposits is undetermined in
 most districts.  Butler and others(2) cite vein systems which extend to 400
 meters below the surface.  At the Sunshine Mine in Idaho, uranium traces (but
 not of a commercial grade) have been found below the 900 meter level.(2)
 Probably uranium in some of the better districts extends considerably  below
 the known depth of occurrence.

      Most uranium occurrences in vein deposits are likely of hydrothermal
 origin.  Recent data, however, suggest that some" vein deposits may be  of
 secondary origin, formed by downward-moving waters.

      Geologic terranes suitable for uranium deposits are extremely wide-
 spread.  Undiscovered resources may equal or exceed  those now known.   Re-
 sources of uranium in veins were considered by Butler(2) to range from a few
 million to 10 million tons of ore-grade rock.

 By-Product Uranium From Copper Leach Solution

      The United States Bureau of Mines (USBM)  has demonstrated the presence
 of trace amounts of uranium in certain copper  deposits  of the southwestern
 United  States.   Their studies have shown the practicability of recovering
 the uranium from some copper leach solutions as a by-product of the copper
 recovery.   Unfortunately,  uranium is not found in significant quantities in
 all copper  leach dumps.  For instance,  uranium runs  as  high as 50  ppm  in
 leach dumps from Twin Buttes,  Nevada,  but is as low  as  2 ppm in similar
 dumps at  Butte,  Montana.   The normal range for uranium  in copper dump
 material  is 1  to 12  ppm.

     Thirteen operations were studied  by USBM.   However,  more than twice that
 many more porphyry copper  deposits are known,  many of which should have  com-
 parable amounts  of uranium present.  For  instance, samples  of oxide copper
 ore from Yerington,  Nevada,  contain  uranium.   In addition,  more such deposits
 can be  expected  so that the total  tonnage of uranium resources may be  several
 times larger than quoted.   The total tonnage is a  small,  though significant,
 fraction of that  considered  available  from the conventional deposits.

 By-Product Uranium From Phosphoric Acid Production

     Phosphate rock which  is used for producing phosphoric  acid  is  also  a
 potential source of uranium.   Many phosphate rock  deposits  have been examined
 for uranium content.  Grades higher  than  0.1 percent have been reported, but
 most phosphate rock contains between 0.003 and  0.02 percent U30g.   The
 Florida phosphate rock, which  provides about 80  percent  of  total U. S.
 production, contains 0.01 to 0.02 percent U30g.

     With the increasing cost  of uranium,  there  has been renewed interest in
 its recovery from dilute phosphoric  acid produced by the "wet  process".
Uranium Recovery Corporation  (URC), a subsidiary of United Nuclear  Corpora-
 tion, has just completed its first full-scale module (only  the  initial
 extraction and stripping operations  take place  at  the phosphoric acid plant)
at the W.  R. Grace and Company plant near Bartow, Florida.

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     URC has contracted to install two modules in a new phosphoric acid plant
owned by a subsidiary of International Minerals and Chemical Company near
Mulberry, Florida.  This is nearby to URC's completed central processing
plant.  In addition to the URC work, programs and pilot-scale operations are
being carried out by Westinghouse, Gulf Oil Chemicals, and Freeport Minerals.

Other Unconventional Deposits

     Because of the wide diversity of occurrences of uranium, the potential
exists for uranium resources in many environments not yet adequately under-
stood.  Among the other more promising unconventional deposits are the marine
black shales, coal, lignites, and related carbonaceous shales.  Conventional,
as used here, includes the peneconcordant sandstone deposits and vein
deposits.  Other occurrences are unconventional because they are not
generally produced or, at best, irregularly produced under current conditions.

     A summary of the various types of uranium deposits, their principal
mineral consists, and typical occurrences in the United States is given in
Table 1.
LOCATION OF ACTIVE MILLS

     The locations of active mills within the continental United States are
shown in Figure 2.  The names on the map are cities or producing zones.
There are in some cases three or more active mills operating in one locale,
e.g., Grants, New Mexico.  Table 2 describes each of these mills with regard
to sources of ore and ore mineralization.

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                  TABLE 1.  TYPES OF URANIUM DEPOSITS
                                                     (4)
   Type of deposit
       Principal
    uranium minerals
 Typical U.S.  occurrences
 Vein deposits
 Flat-lying deposits
 in sedimentary
 rocks:
   Vanadium-bearing
   sandstones 'a'
 Copper-bearing
 sandstones
Asphaltic
sandstones

Other sandstones
Limestone
Phosphate rock
Lignite
Bituminous shales
 Uraninite, torbernite,
 autunite, and
 uranophane
 Uraninite,  coffinite
 Uraninite  and uranium
 phosphates, vanadates,
 sulfates,  carbonates,
 and  silicates
 Uraninite, uranium
 hydrocarbons, and
 carnotite
 Uraninite  and coffinite;
 and  uranium phosphates,
 silicates, arsenates,
 and  carbonates
 Uraninite, carnotite,
 tyuyamunite, and
 uranophane
 Carbonate-fluorapatite
Uranium hydrocarbons
and minor secondary
uranium minerals
Uranium-hydrocarbon
complex
 Front  Range,  Colorado;
 Marysvale district, Utah;
 Spokane  area,  Washington.
 Colorado Plateau of
 Colorado, Utah, Arizona,
 and New Mexico.  Black
 Hills area,  South Dakota.
 Powder River Basin,
 Wyoming.  Big Indian
 Wash, Utah.

 White Canyon, Utah.
San Rafael Swell area,
Utah.
Wind River Basin, Wyo-
ming.  Grants-Laguna
area, New Mexico.

Grants-Laguna area, New
Mexico.
Central Florida; Bear
Lake area, Idaho; Utah;
Wyoming; and western
Montana.
Western North and South
Dakota; eastern Montana.


Tennessee.
(a)  Early production from these areas was oxidized or "carnotite-type"
     ore, with the exception of the Big Indian area.
                                   10

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                TABLE  2.   ACTIVE URANIUM MILLS  IN  THE  UNITED  STATES  AND
                               ORE CHARACTERISTICS
    Mill and Location
                            Capacity,
                             tpd  ore
                                                Ore Source
                                                                                      Mineralization
Kerr-McGee Corporation
Grants, New Mexico
                             7000
                             3500
United Nuclear-Homestake
Partners,
Grants, New Mexico

Anaconda Blue Water Plant    3000
Grants, New Mexico
Utah International, Inc.      3400
Gas Hills and Shirley
Basin, Wyoming
Exxon Highland Mill          2850
Powder River Basin, Hy.

Western Nuclear, Inc.        1500
Jeffrey City, Wyoming
Union Carbide Corporation    1350
Gas Hills, Wyooing

Federal American Partners     950
Gas Hills, Wyoming

Petrotomics Company,         1500
Shirley Basin, Wyoming
(Start-up:  1978)

Atlas Corporation            1500
Moab, Utah
Rio Algora Corporation         750
La Sal, Utah

Union Carbide Corporation    2000
Uravan, Colorado


Cotter Corporation            450
Canon City, Colorado

Dawn Mining Company           500
Stevens County, Washington

Conoco and Pioneer Nuclear,  1750
Inc., Falls City, Texas

ARCO-U.S. Steel, Dalco        125
Geoige West, Texas


Wyoming Minerals              125
Bruni, Ttxas
(a)
(a)
       Five  company-owned under-
       ground mines in Ambrosia
       Lake  area.
       Ore from Ambrosia Lake and
       Smith Lake areas, under-
       ground mines.

       Open  pit Paguate Mine.
       Company-owned open pits
       close  to mill site.
Company-owned open pits  at
top of Fort Union Formation.

Gas Hills, Wyoming, district
open pits and underground.
Golden Goose mine in Crooks
Gap area.

Open-pit operations at Globe
and Aljob company-owned  nines.

Company-owned open pits  at
mill site.
Company-owned open pit mine
adjacent to mill.

Six Atlas mines in S.E.  Utah
or adjoining areas of Colo-
rado.  Also 24 underground
Independent mines.

Company-owned underground
mine in San Juan County, Utah.

Sixty different underground
mines in Uravan Mineral  Belt,
45 are company owned.

Principal source is Schwartz-
walder underground mine  near
Golden, Colorado.

"Porphyry" uranium deposit in
Mldnite open pit mine.

Open pit mine at site.


In situ leaching of uranium
from Miocene Oakville for-
mation.

In situ leaching of uranium.
Grayish-colored  sandstone containing from 2 to 5
percent lime,  traces  of Mo and V.

Ore minerals are  coffinite, uraninite, tyuyamu-
nite, and camotite on sandstone or as inter-
stitial filling.   Small amounts of Mo, V, and Se.

Sandstone w/uraniutn as interstitial lenses associ-
ated with carboniferous materials and with kero-
gens.  Ore is low in  lime w/some dolomitic and
bentonitic clays. Traces of Mo and V.
Sandstone w/10-15 percent of clay.  Uranium min-
erals are unoxidized  uraninite and coffinite.
Significant amounts of Se, As, Mo, and P.

3000 ft of interbedded shales and sandstone.
Traces of As and Se.

Cemented sandstone with interstitial occurrence
of autunite and  carnotite.  Traces of Mo and W.
                                     Ore is in sandstone.  Traces of Mo present.


                                     Sandstone containing  1.5 to 3 percent lice.
                                     Traces of Mo and  V.
                                     Ore In Wind River Formation containing uraninite-
                                     coated sandstone  with 3.5 percent CaCC-j.  Traces
                                     of Mo and V.

                                     Fine-grained sandstone w/uranium mostly as urani-
                                     nite and some tyiyamunite ore from White Canyon,
                                     Utah, contains sulfide copper and V.


                                     Ore minerals are  principally uraninite ore
                                     sandstone.

                                     Ores are sandstone containing carnotite and 4-5
                                     percent limestone with 1 percent ^2®$'  Traces of
                                     Ko and Cu.

                                     Pitchblende is main nineral along with 15-20 per-
                                     cent pyritic sulfides, 0.75 percent Cu and 0.15
                                     percent Mo.

                                     Secondary minerals uraninite, coffinite, and
                                     pitchblende.
                                     Sandstone formation  of  interbedded sands, silts,
                                     and bentonitic  clays.   Significant amounts of Ko.
(a)  Capacity In cons per year of yellowcake.
                                                          11

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ro
                         FIGURE 2.  LOCATION OF ACTIVE URANIUM MILLS IN THE UNITED STATES

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                                   SECTION 4

                         MINING AND RECOVERY PROCESSES
 CONVENTIONAL MINING OPERATIONS

      After  a uranium deposit has been delineated and evaluated as economi-
 cally feasible  to mine, a mining method that is physically, economically,
 and  environmentally adaptable to the recovery of uranium ore from the
 deposit must be selected.  Factors affecting the selection of a mining
 method are

      • The spatial characteristics of the ore body (size, shape,
        attitude, depth)

      • The physical or mechanical properties of the deposit and
        the surrounding rock

      • Ground water and hydraulic conditions

      • Economic factors (ore grade, production rates, comparative
        mining  costs)

      • Environmental factors (surface preservation or restoration,
        air and water pollution prevention).

      There  are  two basic types of mining techniques used by the uranium
 industry.   These are surface and underground mining.

 Surface Mining

      A surface  (or open pit) mine is an open-air excavation for the extrac-
 tion  of uranium ore.  It is used to remove uranium ore from a near-surface
 deposit in  any rock type.  This method is best suited to ore bodies of sub-
 stantial horizontal dimensions which permit high rates of production and low
 costs.(!'   Surface mining accounts for more than half of the ore mined and
 uncovers more ore per mine than does underground mining.

      Open pit mining permits a wide production flexibility; it also provides
 for selective mining and has the potential for 100 percent recovery of ore
 within the  pit limits.  Mechanization provides high unit production and
 requires fewer men.  Mine safety, a major problem in underground mines, is
much better in surface mines.(1)
                                      13

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      Open pit mining is used where the ore deposits are near the surface
 and covered with loose, easily removable soil.  Some open pit mining may be
 done at depths of more than 150 meters (492 ft);  but usually, below 90
 meters  (295 ft), underground methods are preferred.(1)   The ratio of over-
 burden to ore removed in uranium mines is unusually large as compared to
 other types of mining with ranges from 8:1 to 35:1.  The expense of removing
 the larger amounts of overburden is justified by  the greater value of the
 product being recovered.(5)

      The pit layout is determined by several factors as follows:^ '

         Orientation of the deposit jointings
         The stripping ratio
         Required rate of  production
         The availability  of equipment
         Slope stability.

      The first step in surface mining is  the removal and  stockpiling of the
 topsoil for later use in  reclamation.  This is usually  accomplished with
 tractor scrapers.   The deeper overburden  is then  removed  by scrapers or
 power shovels and hauled  to the disposal  area.  Some blasting and ripping is
 also  required.   Optimally,  the ore body is divided  into areas so  that one
 area  may be stripped  before starting  the  stripping  on the next.   This will
 enable  mining to  start  before the whole ore body  is exposed.   Overburden
 from  the first  part of  the  mined area will be placed  on the surface, but
 overburden  from the succeeding areas  will be used to  backfill areas where
 mining  has  been completed.   The overburden is then  covered  with topsoil and
 seeded.   The  final  area of  the pit is left open,  its  sides  graded,  and
 remains  as  a  lake,  if it  is below the water table.

     When the ore body  has  been exposed,  it is cleaned  of waste material
 with  tractor  scrapers and bulldozers.   Ore is blasted or  loosened with
 rippers  and mined with  backhoes  working on benches  and  loaded  onto  trucks for
 hauling  to  the mill.

     Some problems  are  encountered however,  in surface mining, including
 adverse weather limitations  in some areas,  and environmental  problems such as
 surface scarring, dust, noise,  and vibrations from blasting.

     Ground water intrusion  also  has been  a  problem in many of the open pit
mines.  Water influx  occurs  in any surface mine which penetrates  the water
 table and water seepage must be removed for mining  to progress.  The tradi-
 tional and an effective mine dewatering method is to allow the water to  drain
into the mine and to  collect in a sump via a system of ditches.  From the
collection sump, the water is pumped out of  the mine.  In this way, the  floor
of the mine is kept workable.  As the mine is deepened by removal of over-
burden or ore, the mine floor is reditched.  This  method requires care  in
scheduling the mining to assure that the sump is always the lowest point.   It
also requires regular, sometimes continuous, maintenance to keep the sump and
ditch network clear.  Water seepage from the exposed mine walls can often
                                      14

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 make necessary  the  provision of flatter wall slopes and/or benches and thus
 larger  stripping requirements, due to stability considerations.

      Water  pumped from mines may be discharged onto the land surface; for
 example,  to control dust, pumped through an ion exchange plant, or used as
 mill process water.  Mine water discharged to the environment may be
 decanted  through settling ponds to remove suspended solids before
 being released.

      A  method of reducing water influx dewatering is the use of a ring of
 wells located around the periphery of the mine.  With proper placement, these
 wells cause a localized depression in the intercepted water tables.  This
 method  usually  produces a highly clarified water.  However, the locally
 induced piezometric  drawn down regime may influence a slightly larger area
 than the  sump collection method.

      The  amount and  quality of developed mine water is also site and situa-
 tion specific.  Surface mine dewatering rates reported in the literature
 range from  less than 1890 to more than 11,000 1pm (500-3000 gpm).(6)

 Underground  Mining

      Underground mining methods are used where the depth of the deposit makes
 the  removal  of  the  overburden too costly.  A mining system is selected or
 developed on a  safety and cost basis; suitable ground support and sometimes
 preservation must be provided.  The choice of a mining method usually is
 dictated more by the spatial or mechanical characteristics of the deposit
 than by any  other factor.

      Underground mining produces environmental problems principally by the
 discharge of mine waters into streams and by surface disturbances such as
 subsidence,  both concurrent and subsequent to mining.^'

      Room-and-pillar mining is a common variation used for underground
 mining  of uranium.  Suitable deposits for exploitation by room pillar are
 relatively flat-lying or slightly dipping deposits in which the ore is of
 uniform grade and thickness.  Room and pillar and modified room and pillar
 are  methods  of  cutting up a deposit by excavating a grid of rooms separated
 by pillars of uniform cross-section.  Many grid layouts have been employed,
 including systems with rib pillars and square pillars with checkerboard
 spacing.

      Veins and  steeply bedded deposits are often mined by shrinkage
 stoping.  This method is basically an overhand stoping system in which part
 of the  broken ore is accumulated as the stope is completed.  The ore gains
 30 to 50 percent in bulk as it is broken and some ore must be periodically
withdrawn through chutes or drawpoints in order to maintain a working floor
 for  additional mining.  In general the vein material must be strong enough
 to stand unsupported across the width of the stope.  When broken, it should
 not  pack to  the degree that it cannot be withdrawn.  In deposits which
 approach vertical, hanging wall and footwall rock must be relatively
                                      15

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 competent  to prevent failure, both for safety consideration and prevention of
 excessive  dilution of ore.

 In-Situ and Heap Leaching

      Recently interest has increased in some areas in the use of in-situ
 leaching of underground deposits of uranium.  This is especially true in
 South Texas where Mobil, Wyoming Minerals, and ARCO are actively engaged in
 pilot scale or production programs.('»°/  Investigations are also under  way
 in Wyoming.(9)

      In-situ mining simply means the leaching oi  the ore in the geological
 formation in which it occurs.  The subsurface deposit is flooded with a
 leach solution which is subsequently pumped to the surface ready for  concen-
 tration, precipitation, dewatering, and drying.   Thus porosity and permea-
 bility are all important in solution mining for uranium.  The rock surround-
 ing the ore body also should be relatively impermeable.   This is necessary to
 help contain the leach solutions within the producing formation so that
 surface and ground waters do not become contaminated.

      Currently in-situ mining projects  for uranium are using  a sodium or
 ammonium carbonate solution for leaching of the ore.   Sulfuric acid leaching
 has been tried but is not now favored since excessive precipitation of cal-
 cium sulfate may cause plugging of  the  leaching channels.   Recovery of ura-
 nium values from the  pregnant solution  is normally done  by  resin ion
 exchange systems followed by conventional concentration,  precipitation,
 and drying.

      Solution mining  is  also being  applied  commercially  to  remove  uranium
 from waste  heaps  or piles  and is, rather  broadly,  termed  heap  leaching.
 Heap leaching  is  particularly useful  for  the treatment of low-grade ores
 which may be located  at  a  considerable  distance from  the  processing facili-
 ties.  Uranium recovery  can  be done at  the  site or  the solutions pumped or
 hauled to the recovery plant.  Again, conventional  processing  such as resin
 ion  exchange is used  to  recover  the uranium.
CONVENTIONAL RECOVERY PROCESSES

     The following discussion is only meant to provide a general view of the
processes used for extraction of uranium.  For a detailed description, please
refer to Merritt who provides a comprehensive and relatively recent treatise
on the subject.(4)

Ore Preparation

     Ore preparation steps in the mill consist primarily of crushing, grind-
ing, and blending; and these operations are similar to the corresponding
processes used for other ores.  Conventional equipment is used for crushing
                                      16

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 the ore  to less  than 2.5-cm sizes.  Grinding is usually done wet to a size
 typically between 20 and 200 mesh.

      The uranium minerals usually form a coating on sand grains which is
 partially removed in the grinding operation.  The slimes thus generated have
 a high uranium content and are sometimes separated from the sands for
 separate treatment.  Usually, however, a slime separation step is incorporated
 later in the operation.  Uranium milling differs in this respect signifi-
 cantly from conventional milling operations where slime separation often
 takes place early in the process to enable efficient application of. other
 physical separation techniques.

 Acid  Leaching

      Acid leaching is the most commonly used method for extraction of the
 uranium  values and is always done at atmospheric pressure.  Sulfuric acid is
 used  in  the acid leaching process.  To oxidize reduced uranium minerals,
 reagents such as Mn02 and NaC103 are added although aeration is often suf-
 ficient.  Leaching takes place in a number of agitated vessels arranged in
 series.  The larger operations normally use rubber-lined steel tanks;
 smaller  operations frequently use wooden vats.  The total retention time in
 the leaching vessels typically is between 10 and 20 hr, depending on the
 leaching characteristics of the ore.  Slightly elevated temperatures (35 C)
may be used to reduce the total leaching time.

      The acid consumption for leaching depends very much on the carbonate
 content  of the ore and may range from 14 to 160 kg/metric ton of ore treated.
The consumption  is commonly between 25 and 50 kg/ton.  The pH of the leach
 solution ranges between 0.5 in the tank where fresh acid is added to about
1.2 in the last  tank.

Carbonate Leaching

      Carbonate leaching is used when the carbonate content of the ore to be
treated  is so high that the acid consumption would be prohibitive if acid
leaching were used.  Carbonate leaching is much slower than acid leaching
and to improve the extraction rate, elevated temperature and pressure are
sometimes used.  Leaching vessels are either Pachuca tanks, or autoclaves, or
a combination of the two.

      In one plant, using autoclaves only, the total retention time is 6-1/2
hr at a temperature of 120 C, and under a total pressure of 5 atm.  In
addition to the air used to achieve the operating pressure, a small amount
of ammoniacal cupric sulfate solution is added to help oxidize the ore.  The
sodium carbonate consumption is about 25 kg/ton of ore.

     Another mill leaches the ore at atmospheric pressure in Pachuca tanks
at approximately 80 C for a total period of 96 hr.  No oxidizing agent is
used besides the air used in the Pachucas.  The soda ash consumption is about
35 kg/ton of ore.
                                      17

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      In another plant the ore is first leached for 4-1/2 hr in autoclaves at
 93 C and 5 atm pressure, followed by 36 hr of leaching at 80 C in Pachucas.
 Again, no oxidant besides air is found to be necessary.

 Liquid-Solids Separation

      The uranium-bearing solution obtained by either acid or carbonate
 leaching must be separated from the barren solids prior to solution purifi-
 cation and uranium recovery.  Conventional techniques that also find wide-
 spread application in the uranium milling industry are filtration and coun-
 tercurrent decantation.   A method that is only widely used in the uranium
 industry is the resin-in-pulp process.

      Filtration as the primary separation technique is usually preferred  in
 carbonate circuits.   This is because carbonate solutions are often recy-
 cled; the filtration process requires very little dilution as compared with
 countercurrent decantation,  the most likely alternative.   Also, carbonate
 solutions are very viscous and are difficult to wash away.

      Countercurrent  decantation is the most widely used method in mills
 with  acid circuits.   The underflow from the countercurrently operated thick-
 eners is  pumped to a tailing disposal area.  The overflow is treated with
 flocculating  agents  and  then passed through a precoat filter to clarify the
 solution  for  further treatment.

      In resin-in-pulp circuits,  cyclones  and classifiers  are used to first
 separate  the  coarse  sand fraction from the slimes.   The coarse fraction is
 readily cleaned by countercurrent washing.   The slime fraction is contacted
 with  an ionic resin  which adsorbs the uranium from the solution.   In most
 operations  the resin is  contained in open baskets  covered with either stain-
 less  steel  or plastic screen with 28 mesh openings.   Some mills use  a con-
 tinuous countercurrent process  in which the resin  is  directly suspended in
 the slime slurry.  The slurry is  contained  in cells  arranged in series to
 form  a  bank.   After  leaving  a cell  the  slurry is passed over a vibrating
 60-mesh screen which separates  the  resin  from the  pulp.   The resin is
 dumped  into the adjacent  cell on  one side while the  pulp  moves to the next
 cell  on the other  side.   After  six  to  eight adsorption stages,  the pulp is
 barren  and  can be  discarded.   Fresh  acid  eluant  solution  is  used  to  desorb
 the uranium from the resin.   Uranium can  either be precipitated directly
 from  the resin-in-pulp eluate or  extracted  from the  eluate in a
 solvent-extraction circuit.

 Solution Purification and Concentration

     Sulfuric acid is not a  solvent  selective for uranium only.   To  produce
yellowcake of acceptable quality, it is necessary to  remove  impurities such
as molybdenum, vanadium,  selenium, iron,  and many others.  Furthermore,
pregnant solutions from acid  leaching contain only between 0.6  and 2.0
g/liter U308.   This  is too low for efficient precipitation of  yellowcake.
Solvent extraction techniques and, in some  cases, resin ion  exchange
processes are used to achieve both solution purification and  concentration.
                                      18

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     The most commonly used method for purification and concentration of
acid leach solutions is solvent extraction.  The process depends on the
selective extraction of uranium from the pregnant solution to an organic
phase which is brought into intimate contact with it.   Another aqueous
phase, with different acid and salt contents than the  original pregnant
solution, is used to strip the uranium from the organic phase back into an
aqueous phase from which it can subsequently be precipitated.  By proper
selection of the relative volumes of the two aqueous phases,  the I^Og con-
tent of the final solution can be made to be between 30 and 50 g/liter, a
suitable concentration for subsequent precipitation.

     Ion exchange resins are used in about half of the mills  using an acid
circuit.  In most cases, however, they use the resin-in-pulp  system dis-
cussed in the preceding section.  The eluant from these systems usually con-
tains from 10 to 12 g/liter 11303.  Sometimes, these solutions are further
concentrated by solvent extraction.  This provides not only additional puri-
fication, but it also saves on reagents because a much smaller volume of
solution needs to be neutralized for precipitation than would be required
otherwise.

     Two mills use ion exchange resins to extract uranium from clarified
solutions rather than from pulps.  One of these mills  uses a conventional
vertical ion exchange column.  The other uses a unique moving bed system,
pioneered in this mill, and since then applied in at least two cases for
purification of mine water.

     The mills with carbonate circuits use either the  resin-in-pulp system
or precipitate uranium directly from the clarified leach solutions.  Direct
precipitation from carbonate circuits is possible for  several reasons.
Firstly, carbonate leaching is sufficiently selective  to eliminate the need
for solution purification.  Secondly, carbonate leach  solutions have a
U30g content of about 7 g/liter which makes precipitation more efficient
than from the more dilute acid solutions.  Lastly, neutralization of the
solution is not required and, therefore, no reagent saving would be realized
by further concentration.

Product Precipitation

     Precipitation of yellowcake from acid circuits is achieved by neutrali-
zation to a pH of between 6.5 and 8.0.  This is usually done in two stages
to allow precipitation of iron hydroxide and other impurities at a pH of
approximately 4.0.  Any base may be used as neutralizing agent but ammonia is
preferred by the majority of operators because it results in a cleaner product.

     Domestic mills using a carbonate circuit precipitate yellowcake by
addition of caustic soda to achieve a pH of 12.  Uranium precipitates as  the
sodium salt.  In one case the precipitate is redissolved and reprecipitated
to eliminate some impurities.  Other precipitation methods are practiced  in
other countries but have found no acceptance here.
                                      19

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Yellowcake Drying

     Following the precipitation stage, a yellowcake is typically obtained by
filtering or centrifuging the yellowcake slurry.  The moist cake is then
dried and/or calcined by either of two types of equipment.  Most U. S. mills
actually calcine the yellowcake at temperatures from 350 C to 900 C in a
Skinner multiple-hearth furnace.  This apparently decomposes much of the
sulfate which would otherwise be present as an impurity.  Three mills,
however, employ steam drying at more modest temperatures (100-150 C) as a
final treatment of the yellowcake before shipment.
                                     20

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                                  SECTION 5

                       POTENTIAL ENVIRONMENTAL IMPACTS
EXPLORATION

     Uranium exploration in the 1950rs often consisted of flying, driving, or
walking over an area with a portable Geiger counter and about the only environ-
mental effect was the off-road jeep trails that were left.  The shallow deposits
that could be found by this method have been exploited and such deposits will
rarely, if ever, be found now.  Exploration now requires extensive drilling to
locate, delineate, and appraise deeper lying deposits.

Air

     Various air pollutants are generated as a result of the exploration opera-
tions.  Essentially all air pollutants generated are the result of the operation
of machinery, including trucks, drill rigs, backhoes, and other vehicles.  The
pollutants generated are those associated with the operation of internal com-
bustion engines and dust resulting from vehicles traveling over unpaved roads
and trails.  These pollutants include particulates, oxides of nitrogen, carbon
monoxide, unburned hydrocarbons, and sulfur dioxide.  The total quantities of
these combustion products emitted to the atmosphere is dependent on the number
and types of equipment in use, as well as their frequency and duration of
operation.

     The most visible form of air pollutants is dust generated by moving
vehicles.  This effect can be lessened by minimizing the speed of travel over
unpaved roads and trails, and the number of trips within the exploration area.

     It is expected that any impact of exploration operations on air quality
would be slight and restricted to the immediate vicinity of drilling rigs and
that the duration of any such effects would be short term.

Liquids

     Some local and minor alterations to the surface water system of the ex-
ploration area may result from temporary road building and from drilling
operations.  The maximum possible use of existing roads and the program of
reclaiming (grading and reseeding) disturbed areas would serve to assure the
minimum possible disruption to the watersheds.  The planned location of mud
pits distant from zones subject to erosion would minimize possible surface
runoff alterations.
                                      21

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      Care in road building and mud pit placement is important to protect not
 only surface water supplies (i.e., impacts on developed shallow alluvial waters)
 but also confined subsurface water resources.  Procedures designed to minimize
 surface runoff alterations can also lessen the potential for alteration of
 aquifer recharge waters.  The transfixing of various developable aquifers
 presents some potential for the alteration of confined-water characteristics
 (physical, chemical, and biological).

 Land Surface

 Roads—
      The movement and servicing of drill rigs away from established roadways
 will make trails and perhaps even require that a rough road be bladed out.   In
 the semiarid areas where much of this  activity is likely to take place,  these
 off-road trails may persist for many years.   Such roads often become waterways
 during  rainstorms and erode down to unweathered rock and soil parent material.
 Establishment of vegetation along these strips is extremely slow and may never
 occur without a reclamation program.

 Drill Pads—
      A  drill rig, with its attendant equipment,  requires an area about  30 by
 45 meters.   The drill rig itself needs  to be level,  which condition can  be
 achieved either by bulldozing  the area  or by blocking  up the rig.   Rig-leveling
 causes  the  least surface disturbance, but a  certain  amount of vegetation will
 be destroyed just by  activity  associated with the drilling.

      Conventional drilling methods usually require a pit for drilling mud which
 may be  scooped  out by a bulldozer to be 1.5  meters wide and  3 meters  long.   At
 the completion  of drilling,  the  mud can be allowed to  dry and the  scooped out
 soil replaced.   This  small area,  along  with  the  rest of the  disturbed drilling
 pad will be  subject  to wind erosion and may  be slow  to revegetate.   Lubricating
 oils  and fuel which may be spilled or discarded may  also have a  short-term
 adverse  impact.

 GENERAL  IMPACTS  FROM  MINING

 Fugitive Dust

     Particulates  of  ore  and soil  may enter  the atmosphere from  several
 sources.  Underground mine  operations contribute  less  dust than  does  surface
mining.   Underground  mine  sources  are the  ventilation  shafts  which  exhaust the
 air drawn through  the mine.  This  air contains dust  particles  created by  the
mining activities.

     Surface mining activities generate much greater quantities  of  dust.
 Causes of dust include scraping and digging  for removal  of topsoil  and over-
burden,  blasting, and hauling of overburden  and ore; wind erosion of  over-
burden may also occur, contributing to atmospheric dust.  If  the ore  and
overburden are moist, little dust  is created in blasting and  stripping; haul
roads are frequently watered to reduce dust stirred  up by ore  trucks.(6)
Dust from spoil piles may be created by wind action; this dust may be reduced
by reclamation and stabilization of the spoil surface.

                                       22

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     The dust emitted to the atmosphere is primarily silica with small amounts
of uranium, thorium, sulfates, and other elements and compounds associated with
the soil overburden and ores of the particular area.  These materials are dis-
tributed over the landscape.  However, due to the low quantities of dust normally
involved, no significant impacts of dust upon vegetation, livestock, wildlife,
or water quality should be anticipated.  In areas where the ore or overburden is
dry or haul roads are not watered, greater quantities of dust are emitted to the
atmosphere and settle out on the surrounding area.  Vegetation is not normally
significantly impacted by the increased dust, unless it is completely covered,
but utilization of the plants by animals may be reduced.  Large amounts of dust
increase the likelihood of surface water contamination through runoff.

Vehicle Emissions

     Most of the emissions result from the combustion of hydrocarbon fuels in
the heavy-duty diesel-powered equipment used in the mining operations.  These
emissions are primarily particulates, NOX, SOjj, and hydrocarbons.  Surface mine
operations result in considerably more emissions than underground mines, since
the overburden must be removed before the ore can be mined.  The estimated air
pollutants emitted from a hypothetical 1350 MT (1500 ton)/day underground and
surface mine are presented in Tables 3 and 4.  The quantities of pollutants
from vehicles involved in mining will not likely be sufficient to cause a
measurable increase in a region's inventory.

Mine Water

     One of the major environmental impacts associated with mining is the
withdrawal of groundwater to prevent flooding.  Declining water levels in the
tapped aquifers, and possibly adjacent formations, is immediately noticed.(H)
This may affect the availability of local and possibly regional water supplies
for municipalities and industries.  Lowering of the water table may also affect
the vegetation community, especially in arid regions of the west where many of
the plants are dependent on subsurface water.  Water levels in the aquifers
will likely return to pre-mining conditions, after mining operations cease.

     Another of the major environmental impacts of mining is the discharge of
water into the environment.  Water from relief wells drilled around the mines
to reduce mine water influx and water that collects in the mines is often
discharged without any treatment.  Surface mine dewatering rates range 0.77
to more than 11.0 m3/min (205-2904 gpm).  Mine water may contain uranium,
selenium, zinc, sodium, sulfates, nitrates, and other substances.  The com-
position of the water varies with the composition of the aquifers and other
rock formations through and over which the water flows and leaches out the
various substances.  Water discharged from mines also contains suspended
solids picked up as it flows across mined surfaces and through collection
ditches.  The composition of representative discharged mine waters is shown
in Tables 5 and 6.

     The discharge of mine water in the arid west may transform dry washes
and ephemeral streams into perennial streams.  This increased water leads to
changes in biota and land use by wildlife and livestock, particularly in
                                     23

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           TABLE 3.   ESTIMATED AIR POLLUTANT EMISSIONS FROM
                      EARTH HAULING EQUIPMENT AT A 1350 MT/
                      DAY UNDERGROUND MINE
Pollutant
Particulates
Sulfur oxides
Carbon monoxide
Hydrocarbons
Nitrogen oxides
Emissions ,
kg /day
2.4
5.0
41.9
6.9
68.1
           Source:  Reference  6.
          TABLE 4.  ESTIMATED AIR  POLLUTANT EMISSIONS FROM  EARTH
                    HAULING  EQUIPMENT AT A 1350 MT/DAY SURFACE
                    MINE
Pollutant
Particulates
Sulfur oxides
Carbon monoxide
Hydrocarbons
Nitrogen oxides
Emissions
per Operating Day,
Mining
Operations
17.0
35.4
294.2
48.4
484.6
kg /day
Overburden
Removal
18.9
39.3
327.4
53.8
538.4
Source:  Reference 6.
                                   24

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                                      TABLE 5.   COMPOSITION OF DISCHARGE  WATER FROM MINES
                                                                                         (a)
Surface Mines
Applicant
Mine Designation
Mine Location
Flow rate, mVdav x 103
pH
Alkalinity
Total Solids
Total Dissolved Solids
Total Suspended Solids
Total Volatile Solids
Ammonia (as N)
Kjeldahl Nitrogen
Nitrate (as N)
Phosphorus Total as P
Kerr-McGee
Shirley
Basin,
Wyoming
1.7
7.9
180
612
411
163
38
0.22
0.22
<0.01
0.05
Getty Oil
KGS-JY-Mine
Shirley
Basin,
Wyoming
5.4
7.5
164
840
627
49
164
1.33
1.33
0.002
0.07
Utah Intl.
Shirley Basin
Shirley
Basin,
Wyoming
10.9
6.7-8.2
144-150
850-1,275
750-825
40-420
40-92
1.42-1.60
1.42
0-1.06
2.30
Cotter Corp.
Schwartz-
walder
Golden,
Colorado
0.3
7.3
244
1,220
1,042
178
244
0.15
0.55
12.0
0.4
Underground Mines
Union Carbide
Eula Belle
Uravan,
Colorado
0.3
8.6
358
730
590
140
70.7
<0.10
145
0.35
0.2
Union Carbide
Martha Belle
Uravan,
Colorado
0.2
8.4
384
3,103
650
2,453
192
<0.10
0.3
0.39
0.4
Union Carbide
Burro
Slick Rock,
Colorado
0.1
8.8
704
1,790
1,780
6
125
3.3
21.8
1.9
0.15
Source:  Reference 12.
(a)  Composition data given in mg/1 unless otherwise specified.

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                           TABLE 6 .  COMPOSITION OF DISCHARGE WATER FROM UNDERGROUND MINES
Operator
Designation
Location
Flow rate (m3/day x 10 3)
pH
Total dissolved solids
Total suspended .solids
Total solids
so4
Cl
Fe
Mo
Na
NH3
NO.,
Se
V
Mn
Total U
Kerr-McGee^a' Kerr-McGee^'1' Kerr-McGee^3'
Sec. 30W Sec. 35 Sec. 36
Grants Grants Grants
New Mexico New Mexico New Mexico
5.1 14.3


22 100


51 8.5

2.6 5.0
160 200
19 11
1.14 0.35
0.03 0.07
0.7 0.8
0.7 0.05
4.7 19
8.4


38

13


0.3
187
0.05
0.25
0.01
0.9
0.11
3.0
United Nuclear^3"1
Churchrock Mine D
Grants
New Mexico
7.8


118


4.9

0.2
95 *
0.05
0.22
0.04
0.5
0.09
10.4
(a) , •, (b
Kerr-McGee Rio Algom
Churchrock Humeca
Grants La Sal
New Mexico Utah
8.3
7 ,
2962
47
3712
300
1.2 1597
0
0/>
97 1335
0.05 N
0.53
9
0.01 <0
0.8
0.8 N
0.88 0

.6





.16


.D.
.5
.005

.D.
.035
(a)   Average concentrations  in mg/1;  Source:   Reference 11
(b)   Average concentrations  in ppm;  Source:   Reference 13

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arid regions.  The water may enter other streams, where its components contami-
nate the water and are transported to other areas.  The water may also evaporate
leaving behind its dissolved and suspended materials.  Seepage into shallow
aquifers may occur thus contaminating ground water.  Water from mines is some-
times decanted through settling ponds before being discharged into the environ-
ment where percolation into ground water often occurs.

     Heavy metals such as selenium, vanadium, radium, and molybdenum are
potentially toxic elements frequently found in uranium mine water, such as in
the Grants Mineral Belt of New Mexico(H) (see Table 6) .  These elements may
enter the human food chain if the receiving water system is used for irrigation
or livestock watering.

     The use of mine water for dust suppression on haul roads would cause a
gradual accumulation of any dissolved or entrained solids on the roadways.
Depending upon the concentration and composition of these dissolved or entrained
materials, leaching of the accumulated material by rainfall could adversely
affect water quality in local surface drainage areas.  This possibility should
be considered in each area where dust suppression is needed and the water used
for dust control should be treated as necessary to prevent these potentially
adverse effects.

Solids

     The effects of solid wastes revolve primarily around the quantity of
material excavated.  The volume of waste from an underground mine is relatively
small, consisting primarily of the rock and overlying material excavated from
the shafts and haulage drifts.  The mine waste is disposed of on the surface.
The area where this material is placed will no longer be biologically produc-
tive unless it.is reclaimed.

     Surface mining operations require the removal of overburden to depths as
great as 150 meters (492 feet) but more commonly to depths of 30-120 meters
(98-394 ft)(5) ; areas of 160 ha (395 ac) may be excavated.  The range of over-
burden to ore volumes ranges 8:1 to 35:1.(5)  Currently, overburden from
initial pit construction is stored on the surface; as mining continues the
overburden is used to backfill the pit.  Current practices call for the
reclamation of overburden spoils by covering with topsoil and establishing
vegetation to regain lost productivity and reduce erosion.  Approximately
100 ha (247 ac) are required for waste storage at a mine that is expected to
disturb about 400 ha (988 ac) through excavation.(12)  when spoils are not
used to backfill the mine, the area so covered is at least temporily unpro-
ductive.  Spoil material is not conducive to the growth of vegetation without
supplemental treatment.  If the spoils are not seeded or chemically treated,
wind and water erosion may occur and if streams are-nearby, they may become
polluted from spoils runoff.

     A potential problem with backfilling is the possible contamination of
ground water.  This may occur when ground water saturates the backfill
material and substances may leach from the mixed overburden substrates and
enter the aquifers flowing through the area.
                                      27

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 GENERAL  IMPACTS FROM MILLING

 Dust

      Fugitive dust originates from ore stockpiles and mill tailings.   It is
 usually  siliceous in nature but some ores are high in calcium and magnesium.
 Some iron is usually present and small amounts of various elements may be asso-
 ciated with the uranium, such as vanadium, copper, and phosphorus.  Dust from
 ore piles may be reduced during dry and windy periods by wetting.  The quantity
 of tailings dust varies with the treatment of disposed tailings.   Dried
 impounded tailings and untreated, abandoned tailings piles contribute signifi-
 cantly more dust to the atmosphere than moist or stabilized tailings.

      Process dust can be emitted locally from ore crushing and grinding and
 yellowcake drying; however, the quantity of dust escaping is normally kept
 small,  either by wet crushing or through the use of scrubbers.  Scrubbers are
 also used to capture dust during the drying of yellowcake.

      Although uranium and associated metals frequently found in the dust are
 toxic,  their concentrations and the volumes of dust are sufficiently  low that
 their impacts are localized and very minor.(6»12)

 Chemicals

      Gaseous emissions  from milling are from fuel combustion and  the  chemicals
 used in the various  processes.

      The  use of  fuels,  such as  natural  gas, results in the emission of hydro-
 carbons,  SOX, NOX, CO,  and  C02•   These  effluents  are small in quantity and do
 not  result  in a  significant impact  to the local environment.

      Chemicals used  in  the  processing of  uranium  ore give off small quantities
 of various  gaseous effluents  in the mill.   The primary effluents  from the acid
 leach processes  are  S02»  kerosene,  ammonia,  and amines.(10»13)  Approximately
 166  kg/yr (366 Ib/yr) of  kerosene and 129  kg/yr (285 lb/yr)  of S02  may be
 vented  from  a 1814 MT/day (2000  ton/day) nominal plant, (10)   Effluents from the
 alkaline  leach process may  include  ammonia and caustic soda vapors.(13)   xhe
 small quantity of vapor emitted  is  quickly dissipated and is  not  expected to
 accumulate  in the environment or have any  significant environmental impacts.

     Vapors  of organic chemicals enter  the atmosphere via evaporation from
 tailings  ponds.(13)

 Liquids

     Liquid discharges for  acid and alkaline leach  systems  are  approximately
 4.2 and 1.05 cubic meters (1000 and 250 gallons) per metric  ton of  ore
 processed, respectively.(5)  The recycling  of  liquids  considerably  reduces  the
 requirements for water and  chemicals, but  the wastes must  eventually  be  dis-
 posed of.  Water requirements are met by the utilization  of mine water or well
water.  A well is normally  drilled  to meet  the  requirements for potable  water.
                                      28

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The  use  of wells  to supply process water results i'n a decrease in the amount of
water  available in aquifers for other uses, but the quantities withdrawn are not
expected to have  any major long-term effects upon regional water supplies.  The
use  of mine water for process water eliminates the need for process water wells
and  reduces the volume  of mine water discharged into the environment.

     Liquid wastes from mills are aqueous solutions containing various chemicals
(Table 7), leached elements (Table 8), and suspended ore fines and other solids.
An analysis of an alkaline leach mill effliient is shown in Table 9.

     Liquid wastes from milling operations are discharged into settling lakes
but  until recently the  wastes were often discharged directly into stream
channels.  The current  practice is to discharge the liquids along with solids
into settling basins where the liquids either evaporate or percolate into the
soil;  excess water in the pond may be treated and discharged into streams or
injected into deep wells.  Some of the clarified water may be recycled for use
as process water.
     Wastes from an acid leaching process have a pH of about 1.5 to 2.0.
These liquors contain  the unreacted portion of the sulfuric acid leaching
agent and other soluble inorganics such as calcium, sodium, magnesium, and
iron cations with sulfate and  chloride anions.  Small amounts of other metals
leached from the ore are also  present.  One to three percent of the ore is
dissolved in the process waste.  The major organics present are those of the
raffinate solution (primarily  kerosine, amines, and isodecanol) introduced in
the solvent extraction process.  A mill processing 1,814 MT (2000 ton) of ore
per day produces about 2,722 MT  (3000 tons) per day of waste milling
solution. (10)  The waste milling solutions are used to transport the tailings
sands and slimes to the disposal site.

     Waste solutions from alkaline leach processes have a pH of about 9.5 to
11.0 from the unreacted carbonate-bicarbonate leach solutions . (14)  The use of
an alkaline leach system is more specific for uranium than the acid leach
system and fewer elements are  leached from the ore. (15)  Water requirements
for the alkaline leach system  are about one-fourth those of the acid leach
system.  A portion of  the alkaline process water is discharged to the tailings
pond to prevent a buildup of dissolved solids while the remainder is recycled
through the plant.  Some pond  water is often recycled through mills to reslurry
sand and slimes for disposal.  The volumes of liquids in ponds are reduced
through seepage into the soil, evaporation, or, after settling and filtration,
by stream discharge or deep well injection.

     The quantity of seepage from the ponds varies, d_epending upon the pond
design.  In evaporation-percolation ponds, seepage may account for as much as
85 percent of the losses; in clay-lined ponds with a buildup of tailings
seepage may account for only 7 percent of the loss.  Excess liquids from ponds
may be discharged to streams or disposed of underground in areas where suffi-
cient land is not available; the water is neutralized and treated to remove
heavy metals and other contaminants and may flow through a series of settling
ponds before discharging or injecting.
                                      29

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              TABLE 7.  CHEMICALS USED IN MILLING  OPERATIONS
        Acid Leach Process
   Alkaline Leach Process
 Acid Leach Circuit:
     sulfuric  acid
     sodium chlorate

 Liquid-Solid  Separation Circuit;
     polyacrylamides
     guar gums
     animal glues

 Ion-Exchange  Circuit:
     strong base anionic  resins
     sodium chloride
     sulfuric  acid
     sodium bicarbonate
     ammonium  nitrate

 Solvent  Extraction Circuit:
     tertiary  amines
      (usually alamine-336)
    alkyl  phosphoric acid
      (usually EHPA)
    isodecanol
    tributyl  phosphate
    kerosine
    sodium carbonate
    ammonium  sulfate
    sodium chloride
    ammonia gas
    hydrochloric acid

Precipitation Circuit:
    ammonia gas
    magnesium oxide
    hydrogen peroxide
Alkaline Leach Circuit:
    sodium carbonate
    sodium bicarbonate
    ammonium carbonate
    ammonium bicarbonate

Ion-Exchange Circuit:
    strong base anionic resins
    sodium chloride
    sulfuric acid
    sodium bicarbonate
    ammonium nitrate

Precipitation Circuit:
    ammonia gas
    magnesium oxide
    hydrogen peroxide
Source:  Reference 5.
                                     30

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        TABLE 8.  TRACE ELEMENTS LEACHED FROM ORE
                  BY MILLING PROCESS
             Magnesium
             Copper
             Manganese
             Barium
             Chromium
             Molybdenum
             Selenium
             Lead
             Arsenic
Vanadium
Iron
Cobalt
Nickel
Zinc
Thorium
Uranium
Radium
   Source:  Reference 5,
 TABLE 9.   ANALYSIS OF AN ALKALINE LEACH MILL TAILINGS
           EFFLUENT
Solution Analysis
U3°8
Mn
Cu
Fe
Zn
so4
co3
HC03
Th
Na
PH
Solids Analysis
U3°8
Mn
Cu
Fe
Th
ppm
6.8
0.01
0.01'
1.0
0.6
7,500
4,000
1,100
2.0
7,100
9.5
Percent
0.017
0.01
0.0028
1.36
0.0005
Source:  Reference 13.
                           31

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      Water seeping from tailings ponds may contain many contaminants  such as
 nitrates, sulfates, trace elements (e.g., selenium in the Grants,  New Mexico
 area) and organic chemicals.'^,12)  Ground and surface water may become  polluted
 as a result of seepage.  Numerous radiological studies have illustrated  that
 pollutions of ground and surface water occurs from seepage and mill discharge.
 Contamination of wells by nonradiological pollutants resulted in water unfit  for
 livestock in Colorado.  Nitrates, which travel more rapidly in soil than some
 other constituents, have polluted ground water in New Mexico.  Trees  have died
 down-gradient from a tailings  pile in Colorado, reportedly indicating a  high
 mineralization of ground water. (5)  Ground water contaminated with selenium and
 nitrates has been shown to occur near tailings ponds in the Grants Mineral
 Belt of New Mexico.(H)  In some areas where seepage is a problem, catchment
 basins or wells have been placed downslope from the pond to intercept the con-
 taminated water and pump it back to the tailings pond.

      Surface water may become  contaminated through ground water discharge into
 ponds or streams or by discharges from mill operations.   Some seepage may occur
 along the tailings pond dam and surface ponds may develop in low areas near the
 tailings ponds.   Prior to the  use of  waste treatment facilities, wastes  were
 discharged directly into streams.  This resulted in the elimination of most
 aquatic life immediately below the discharges.   The most toxic effects were
 from the raffinate components.(16,17)   No wastes are now discharged to streams
 which have not  been treated to reduce the toxic components of the  liquids.
 Treatment may include  decanting through a series of settling ponds, neutralizing
 the  acid, removing thorium and other  metals,  and precipitating solids. (-5)  Con-
 taminants occurring in treated  effluents  are  not expected  to create any  environ-
 mental  problems  because of the  low levels and characteristics of  the  chemicals
 involved.

      Liquid wastes may be  injected into deep  wells  for  disposal.   The disposal
 zone  is  usually  hundreds  of feet  below the surface  and must  be separated from
 aquifers  by  impermeable formations or  contamination of  present or  potential
 water supplies may occur.   Also,  the  injection  well must  be  properly  cased to
 prevent  aquifer  contamination.  Contamination of aquifers  from injected  wastes
 appears  to have  occurred in New Mexico.(H)   The effluents are treated to
 remove suspended  solids  to prevent plugging in  the  zone  and  to retard growth
 of microorganisms.   If  the disposal zone  material will not neutralize the
 wastes,  the effluents  are  neutralized  before  injection.

      Tailings are  presently discharged into impoundments  primarily to retain
 the solid wastes,  but  they are  also designed  to  serve as  retention and
 settling  basins for  the  liquid  wastes.  The pond sizes vary  with the  amount
 of land available,  disposition  of  liquid  effluents,  and  type and size of mill.
 Ponds range from a few  to  more  than a  hundred hectares  in  size with one  or
 more  ponds per mill.  A 1,814 MT/day mill in  Wyoming requires  a tailings
 disposal  area of about  60  ha.(10)

      Tailings are  discharged into  impoundments,  usually  against the upstream
 edge  of the dam, thus forcing the  free  solution  away from  the  dam.  Another
method is  to separate the  sands from the  slimes  and  use  the  sands  to  increase
 the dam height while depositing the slimes in the inner  portion of  the pond.
As the slimes precipitate  they  act as  a sealant  to  reduce  seepage  from the
pond.
                                      32

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     An  ideal  tailings pond to reduce the impacts of seepage of contaminants
 and  to confine the waste solids should be near the mill located in a natural
 ravine with four basic qualifications:  (1) limited runoff, (2) downstream
 openings  capable of being dammed, (3) adequate storage volume, and (4) an
 underlying impermeable geologic formation.  Natural runoff should be diverted
 from the  tailings pond to prevent flooding during high rainfalls.  The dam
 would be  constructed with a clay core to prevent seepage and an outer shell of
 erosion resistant material.  If the pond is not located on an impermeable for-
 mation, a clay blanket should be placed over the entire basin behind the dam to
 reduce seepage.

     Tailings  ponds support little, if any, aquatic life because of their pH
 and  toxic substances.  However, their effects on birds, particularly waterfowl,
 and  other wildlife which may inadvertently use the ponds are not known.(6,10,18)
 It is expected that waterfowl in the central and pacific flyways do land in the
 ponds during migration, particularly in the arid western regions of the U.S.
 The  birds probably do not remain in the ponds for any extended period of time,
 but  they  can be expected to ingest some of the solution.  The effect of the
 chemicals upon feathers and skin, toxic effects, bio-accumulation, or suit-
 ability of the affected birds for human consumption has not been evaluated.

     Sewage treatment facilities are necessary to handle the needs of the
 employees.  The facilities consist of aerated lagoons, septic tanks with leach
 fields and oxidation ponds.  Effluents from the facilities are discharged to
 the mill  process water system or tailings pond.

 Solids

     Large quantities of solid wastes must be disposed of at milling sites.
 Approximately  98 percent of all processed ore is discharged as tailings.  Over
 six million metric tons of tailings were produced by mills in 1974.(5)  This
 waste is  disposed of in tailings ponds and consists of approximately 80 per-
 cent sands and 20 percent slimes.(5)  Some solids are also suspended in the
 liquid effluents.

     Old methods of tailings disposal were to discharge the wastes directly
 into streams or to create piles, frequently near the streams.  Direct discharges
 resulted  in high sediment loads and dissolved solids in the streams.  Tailings
were frequently washed into streams by high waters and water percolating through
 the piles leached out contaminants that moved into ground water and streams.
 Tailings  piles were not reclaimed when milling operations ceased.

     Several types of environmental problems may result from tailings solids.
 Substances (e.g., selenium and nitrates) may leach from the tailings and enter
 ground and surface waters when the tailings basin is permeable.  This has been
 shown to  be a  problem in the Grants Mineral Belt area of New Mexico. (H)  Tail-
 ings must be kept moist to prevent wind erosion.  Otherwise the tailings
particles will be transported to adjacent lands and waters where contaminants
may be taken up by crops or ingested by livestock.  Abandoned tailings are
biologically unproductive due to their high acidity or alkalinity, lack of soil
                                       33

-------
  and moisture  and  blowing  sand.   If  tailings ponds are to be  covered with soil
  when  operations cease,  additional areas must be disturbed to obtain this soil,
  thus  increasing the area  to be  reclaimed.

  SPECIFIC IMPACTS  FROM TYPICAL
  MINING-MILLING OPERATIONS

       This section presents a summary of the environmental impacts from example
  uranium processing categories.   It  is based on field visits  to typical plants
  and information obtained from the literature.  The following categories and
 number of plants in each category were selected for evaluation:

                                                              Number
                         Category                             of Plants

       (1)  Open pit mining-acid leach process                   8

       (2)  Underground mining-acid leach process                4*

       (3)  Underground mining-alkaline leach process            4*

      (4)  In-situ  mining                                       2

 Open Pit-Acid  Leach  Process

     This  industry category is  the most prevalent  in total number of plants (8)
 and accounts for about  50  percent of the total  U.S.  production  of yellowcake.
 The plants in  this category,  for the most  part,  are in various  geographical
 sections but the majority  of  the plants are in  Wyoming.   Table  10 lists these
 plants and certain aspects  concerning the  processing method to  produce
 yellowcake.

     The open  pit  acid-leach  category is typified  by the Exxon,  Highland Mine
 located  in the Powder River Basin of Wyoming.   The flowsheet  for this  mill  is
 shown  in Figure 3.  Following is  a discussion of the various  environmental
 impacts  indicated  in this  figure.

Mine Water—
     The influx of water to open  pit mines  is discussed  in  detail in the pre-
 ceding section.  This general impact occurs in  the Highland Mine  since the  pit
 is below the local water table.   The water  is controlled by a system of ditches
and a  sump from which the water is pumped  to a  settling  basin.   Final  disposal
of the water is to the mill process  or  the  tailings  pond.

     Another aspect pertaining to mine water is the  use  of diversion dams to
direct rainfall away from the open pit  operations.   Three such dams  are used
at the Highland Mine and the water is currently discharged to a nearby stream.
 Includes one plant which has both an acid and an alkaline leaching circuit.
                                       34

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                              TABLE 10.  PROCESS  VARIATIONS USED BY ACTIVE URANIUM PLANTS
     10
 ID
 m
 a
 n


 CD
Pi

5
Liquid/Solid Concentration Precipitation
Plant Location Separation Method Method Reagent Dryer
Open Pit Mine Acid Leach Process
Exxon Wyoming
Utah International, Inc. Wyoming
Union Carbide, Uravan Colorado
Union Carbide, Gas Hills Wyoming
Petrotomics Company Wyoming
Anaconda Company New Mexico
Conoco and Pioneer Nuclear, Inc. Texas
Dawn Mining, Company Washington
CCD
CCD
CCD
SS
CCD
SS
CCD
CCD
SX
IX + SX
IX
RIP
SX
RIP
SX
IX
NH3
NH3
NH3
NH3
NH3
MgO
NaOH
NH3
MH
SD
MH
MH
MH
SD
--
"••
Underground Mine-Acid Leach Process
Kerr-McGee Nuclear Corporation New Mexico
Federal-American Partners (&) Wyoming
Atlas Corporation (acid circuit) Utah
Western Nuclear, Inc. Wyoming
CCD
SS
CCD
SS
Underground Mine- Alkaline Leach
Rio Algom Corporation Utah
United Nuclear-Home stake Partners New Mexico
Atlas Corporation (alkaline circ) Utah
Filtration
Filtration
SS
SX
RIP + SX
SX
RIP + SX
Process
None
None
RIP
Cotter Corporation Colorado CCD + Filtration None
In- Situ
Atlantic Richfield Company Texas
Wyoming Minerals Texas
(a) This plant uses some ore from open pit mines
Mining
--
M ••

Legend: CCD - Continuous countercurrent decantation RIP -
SS - Sand- slime separation
SX - Solvent extraction
IX - Column ion exchange
MH -
SD -


IX
IX

Re sin- in- pulp system
Multiple hearth- skinner
Steam dryer-Proctor and
350 F)
NH3
NH3
NH3
NH3

NH3
NaOH
NH3
NaOH

NH3



dryer
SD
MH
MH
MH

--
MH
MH
MH

SD



(600-1500 F)
Schwartz (200-



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                      Fugitive
                        Dust
Organic
 Vapors
OJ
                                                                                   Yellowcake
                                                                                   Precipitation
                                                                                    Yellowcake
                                Figure 3.   Uranium extraction flowsheet, open pit-acid leach process.

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Fugitive Dust—
     This impact is discussed in detail in the preceding section.

Particulate Emissions—
     At the Highland Mine, ore is crushed by a jaw-crusher and stored in silos
prior  to feeding into a rod mill.  Particulate emissions are generated at both
the crusher station and the ore transfer and storage facilities.   The emissions
are controlled by two Ducon scrubbers at the crusher and ore silos.   These
scrubbers are rated at 95 percent efficiency and would result in a total partic-
ulate  emission of about 130 tons per year.(10)

Tailings Pond Seepage—
     This potential environmental impact is perhaps the major consideration
within the uranium industry.  Impoundment of all mill wastes to a tailings pond
is almost universally applied.  For the Highland Mine, it is estimated that
about  2000 tons per day of solid wastes and 3000 tons per day of liquid wastes
will be disposed of to the tailings pond.(10)  The liquid will have a pH of 1.5
to 2.0.  Included in these wastes are various heavy metal compounds, organic
materials such as kerosine (165 kilograms per year) and ammonia.

     Ideally, the tailings pond will be a final disposal with evaporation
taking care of much of the liquid effluents.  However, seepage can occur from
the pond and has been noted at the Highland Mine.  The current seepage is low,
has a  neutral pH, but is high in sulfates.  It is currently being pumped back
to the pond from a collection sump and is monitored closely.

Organic Vapors—
     Vapors of kerosine and ammonia are, of course, prevalent in any solvent
extraction and precipitation process.  This impact, however, is not of signif-
icance except as it pertains to plant personnel.

Dryer  Emissions—
     Emissions from the drying or calcining of yellowcake prior to shipment are
an environmental impact in all uranium plants.  At the Highland Mine, the yellow-
cake is dried at about 300 C in a gas-fired furnace.  The exhaust gases are con-
trolled by a Tubulaire wet scrubber estimated at 99.3 percent efficiency.  Dust
emissions of U308 are estimated at about 380 kilograms per year.d0)  In
addition the dryer exhaust would contain organic vapors from decomposition of a
polyacrylamide flocculant, and small quantities of ammonia and S02 •

Underground Mine-Acid Leach Process

     This category accounts for almost one-third of the^ total production of
uranium in the United States.  However, only four plants are contained in this
category.  The major production is obtained in the Grants Mineral Belt of New
Mexico.

     In this category, the basic process of uranium extraction remains essen-
tially the same as described in the previous category.  However, due to under-
ground mining operations, there is an added impact of underground mine water.
A generalized flowsheet for this type of mill is shown in Figure 4.  This
                                      37

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                                                                       Recycle  Resin
oo
1 t
1 Under- 1 fc Jaw 1 RIP Circuit Sweco Elution
ground f™ 	 	 * Crusher UCountercurrent) ~^- Screen r Circuit ^ niter -».,
i Mine
1 . . i '
' t J ,'
| Secondary
Mine Water Cone ' Particulate
j _ Crusher i -Emissions
r-1-- "2, 1 •
| Resin ' ! ,
r— I Ion i ' — •-• Rod
1 [Exchange ' | Mill
1 ! _ » '
To SX Ball
Circuit Mill
H0SO. 	 , | 	 Steam
24 ]
1 MO. — i r— Iron Powder
n 2 1 i " * T
Trnn fnH ,1.1 ,1 I ,
Mltle T«o^U4«« f
Leacnine -« 	 '
Water • m ,
• j Tanks
HO 	
' t ''
b limes
Separation ;
Sands
Tailings
Seepage ^
H20
SU
Organic Pregnant Liquorf
Vapors L "™"
• Solvent U* 	 .
.mes Extraction ! *
^L L->
I Stripping ,
T" 	 "" '•'
Pregnant Barren
Strip Organic
NH3 ...
if f ^
; Yellowcake
i Precipitation .
1 	 i-T- 	 1 _-— CNH . •> _ SO .
1 	 1 1 ^—-^'2 4
k Bleed ,. T . ,
*^ 	

Pond
_, 	 ^ 	 	 _.^_
Thickener '
V" i ^L
\ ! Particulates
^Centrifuge & Vapors
— i- .... :
r 	 	 	 	 .„„ j
Dryer
\ — p-
Yellowcake
                           Figure 4.   Uranium extraction flowsheet, underground mine-acid leach process.

-------
flowsheet  is highlighted with the sand slime separation and resin-in-pulp (RIP)
circuits.  The various environmental impacts due to this type of operation are
discussed  below.

Mine Water—
     The impact of mine water from underground mining is higher than that of
the open pit mining operation.  In this case a substantial amount of uranium is
dissolved  in the mine water.  For example, at the Kerr-McGee plant in New
Mexico, the mine water typically contains 2-12 ppm 11303, and this water is
processed  at the mine site to recover the dissolved uranium by resin ion ex-
change in  fixed bed columns.  Portions of this effluent water (uranium stripped)
are pumped back for the underground leaching operation and the remainder is
disposed of.  After treatment, the mine water will typically contain about 1.0
ppm 11303.

Particulate Emissions—
     Most  of the particulate emissions occur during primary and secondary
crushing of the ore.  The emission sources are.controlled by wet scrubbers.  No
information is presently available on emission rates for example plants in this
category.

Tailings Pond Seepage—
     For sand-slime separation circuits, the slime portion of the tailings is
impounded  whereas the sand fraction Is used for dam-building purposes.  The
tailings will have a low pH of 1.5.  Most of the metal and organics content of
of the tailings remain in the pond.

     Seepage from the tailings pond does occur.  In some mills where the tail-
ings water is not returnable for use in the mill because of its high dissolved
solids content, the deep well disposal technique is practiced to dispose of the
solution.  For example, at the Anaconda plant in New Mexico, up to 1500 1pm are
disposed of by deep well injection.  In one case, however, the excess water,
after neutralization, is discharged to the Colorado River.

Organic Vapors—
     The impact due to organic vapors is not significant except as it pertains
to plant personnel.

Dryer Emissions—
     The impact due to dryer emission may be significant, however, the exhaust
gases (e.g., U30g dust, S02, and other organics) are typically controlled by
wet scrubbers.  Estimates of these emissions are described for the previous
category.

Underground Mining-Alkaline Leach Process

     Although underground mining is the most common method of uranium mining,
the combination of underground mining and alkaline leaching process is utilized
by only a  small proportion of the uranium mills.  This category accounts for
only about 15 percent of the total U.S. production of yellowcake.
                                      39

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      An example of the underground mining-alkaline leach category is the Humeca
 Mill operated by the Rio Algom Corporation in La Sal, Utah.   The flowsheet for
 this mill is shown in Figure 5.  A discussion of the various environmental
 impacts indicated in this figure follows.

 Mine Water—
      Water from the production shaft is utilized in the mill process.   Most of
 the water from the ventilation shaft is diverted to a nearby ranch with the
 remainder being used in mining operations or disposed of in  the tailings pond.

 Mine Air Particulates—
      The high air flow rate and low quantity of particulates (2.2 mg/m3) will
 result in a very negligible impact.

 Fugitive Dust—
      Fugitive dust is minimal;  its impact has been discussed in the previous
 section.

 Mill Particulate Emissions—
      Air cleaning  equipment has been installed at  the ore  transfer areas,
 crushing  plant,  and  ore sampling room to remove particulate  matter from the
 air  before it is discharged to  the atmosphere.  In these areas  the air  is
 passed through cloth  bag  filters.   Vapors and dust from the  yellowcake  pack-
 aging  and  drying operations  are passed through a venturi scrubber and centri-
 fugal  eliminator.  All  mill  air effluent contain less  than 0.03  grains/ft3
 (68.3 mg/m3).

 Tailings Pond—  .
      Impact may  result  from  both the  impounded tailings  solution and seepage
 from  the pond.

     The tailings solution has  a pH of  about  9.5 and  contains high concen-
 trations of dissolved solids.   Typically,  a major  part  of the solution  will
 be recycled to the mill process  to  be  used in  leaching.  This results in a
 solution disposal rate  of only  one-fourth that  of  acid-leach mills.

     The impacts of seepage  from the pond have  been discussed earlier.   Ap-
 proximately 500  tons of solids  and  280,000 liters  of waste milling  solution
will be discharged daily into the pond.  Approximately  10 percent  of the
 solution is expected to be lost  through  seepage until the pond is  sealed by
 tailings.

 Combustion Vapor—
     Approximately 32 percent of the flue gas  from the natural gas  fuel  is
directed to the carbonation  tower where  the C02 is absorbed.  The  remainder
of the gas is discharged out a  stack.  The quantities of combustion products
are not expected to have any impacts.

In-S^itu Mining Process

     Recovery of uranium by in-situ mining has been used for a number of years
                                      40

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       Fugitive
         Dust
Under-
ground
Mine
i
I t

Ore
Storage

 Mine
Water
                                     Pregnant
                                     Solution
                           1  Particulate
                           I—Emissions
           Pachuca-Autoclave
                Leaching
   Separart-
               Filtration
                Circuit
   Reclaim
    Wash '           I
   Water         Residue
                                                                Residue
                                                               Flue Gas
                                                                                  1
                                                                                             NH,
                                                                             Yellovcake
                                                                            Precipitation
                                                                                          Participates
                                                                                            & Vapors
Yellowcake
     Figure 5.  Uranium extraction  flowsheet,  underground mine-alkaline  leach  process.

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 but has just recently experienced a rapid growth rate, especially in South
 Texas.  Presently, however, only two plants (see Table 3)  are considered to be
 in a production stage although several other companies are involved in pilot
 testing.  The production of yellowcake by these two plants is currently esti-
 mated at about 250 tons per year which accounts for 1-2 percent of the total
 U.S. production of yellowcake.

      The in-situ mining category is typified by the ARCO plant located approxi-
 mately 16 kilometers southwest of George West,  Texas.   The flowsheet for this
 plant is shown in Figure 6.  Following is a discussion of  the various environ-
 mental impacts indicated in the figure.

 Potential Leachate Losses—
      The potential loss of leachate (ammonium carbonate solution)  produces
 perhaps the primary environmental impact which  could arise from this type of
 operation.   At the ARCO facility, the solution  is pumped into the ore body at
 the rate of about 7000 1pm and ideally is totally withdrawn at the same rate.
 It is realized,  however, that some losses must  occur due to dilution and mixing
 with ground waters and migration of the solution both  in a horizontal and
 vertical plane.   The magnitude and effect of such losses are unknown at the
 present time.   Consequently,  ARCO has numerous  monitor wells to warn of
 potential leachate losses.

      The pumping  of solution  1 mile to and from the recovery facilities also
 could cause an impact to the  environment through pipeline  failures or main-
 tenance activities.

 Sludge—
      Backwash  sludge  from the recovery operations amount to about  15 tons per
 year  at the ARCO  plant.   The  sludge consists primarily of  sandstone  solids but
 probably contains  small  amounts of heavy metals.   It is  currently  disposed of
 by burial.   This  environmental impact is not believed  to be significant.

 Sparge Air—
     This atmospheric emission is considered a  minor impact primarily because
 of the  small volumes  involved.   The gases would contain  some C02  and acid
 vapors.

 Dryer Emissions—
     This impact is similar to other industry categories and is  described in
 previous sections.

 Chemical Wastes—
     All chemical wastes  at the ARCO plant are  sent  to a holding reservoir
 where evaporation  takes  care  of much of  the  liquid  volume.   The  excess  solution
 (less than 400 1pm),  however,  is  disposed of by  deep well  injection,  some 1400
meters below the surface.  Typically the  injected solution  would have  a high
 concentration of dissolved solids and  contain significant  quantities  of heavy
metals such  as molybdenum, uranium,  arsenic, and  selenium,  which makes  the
 solution highly toxic.  The overall  impact both  in  the near and  long  term of
 deep well injection is unknown.
                                      42

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  Potential
  Leachate
   Losses
                                             Backwash Water
, if

	 1^
Pattern ) ' **
, ! Surge
Area ; 6
tank
I
Sparge Air


NaOH
1
*
[7— I 	 1 _ Eluate
c C Storage
t h _ ,
Tank

v r
a c NH, 	
to

' 	 1 	 ' ,Tank

	 	 . — 	 ^, Backwash
Reservoir

pipeline • • . 	 .
• 1 Fil- 1 	 »• Sludge, 15 tons/yr

ii
' • Make-up Chemicals
/-> "^ !
R
a
r e
jj s Solution
0 „ Storage
— "
n 	 ._
~* " Tank „ ,
H SO 1, i • 	 jalL
i r *



i r— • Solution 1


Clarifier i-*-Dust and Vapors
_, ^T^
°"H


                                       	i
                                                                                    Yellovjcake
l       Caust
Caustic Waste
                                  Chemical
                                  Reservoir
                                                       Deep Well
                                                     Disposal,  <100 gpm
               Figure 6.  Uranium extraction flowsheet, in-situ mining process.

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                                    SECTION 6

                                   RECLAMATION
 DISTURBED AREAS

      The objective of reclamation is  to  reconstitute  the disturbed area in
 such a manner that when operations end all  of  the disturbed land will be
 suitable for alternative uses.

 Spoils

      Many of the  known uranium  deposits  in  the United States occur in areas
 where efforts to  reclaim disturbed areas may be expected to meet with rather
 severe problems.   The Wyoming Basins  and Colorado Plateau areas have low
 rainfall,  generally  25 cm (10 in.)  or less, and thus the soils are poorly
 weathered and leached and vegetation has not been prolific enough to develop
 reservoirs of soil organic matter.  This makes reclamation doubly difficult
 because the disturbed soils and spoils are  often not of good quality for
 plants and because sufficient water for plant establishment and growth may
 be lacking or expensive.  Because  they disturb much greater areas, surface
 mines  are of  much  greater concern  than are  underground mines.

 Chemical  and  Physical Properties—
      Soil  has been defined as the  upper, weathered, and biologically moled
 part of  the  regolith.  Another, more detailed definition is:  a natural body,
 engendered  from a variable mixture  of broken and weathered minerals and
 decaying organic matter, which covers the earth in a thin layer and which may
 supply, when  containing the proper  amounts of air and water, mechanical
 support and  in part sustenance for  plants.  These definitions are very broad.
 Overburden materials,  except for the so-called topsoil, which make up mine
 spoils do not  fit within  either definition.   This may be the case in many of
 the areas where uranium ore is found.   These are areas where low rainfall
 inhibits weathering, allows salt accumulation, and limits plant and
microbiological populations.

     Spoils consist of the unweathered and unconsolidated rock, gravels,  and
allied materials which lie from the surface down to as much as 90 m (295
feet).  These materials have not been exposed to weathering processes to  re-
duce the materials to  the finer sized  sands, silts,  and clays  or to leach out
salts.  Neither have they had the biological activities of  plants and animals
to modify the soil physical and chemical  properties and to  add organic mat-
ter.   Thus, the spoils have poor textural properties,  are barren of nutrients
                                      44

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 needed for plant growth,  and  have no  soil fauna  (worms, microorganisms, and
 related organisms)  to aerate  the surface and make nutrients available.

      The usual  practice to  overcome these problems is to cover the spoils
 with  previously stockpiled  topsoil.   Where the amount or quality of topsoil
 make  this uneconomical,  it  may  be possible to add fertilizers and soil
 conditioners  to the spoils  and  thus reestablish the productive capacity of
 the area.   Stabilizing the  spoils against erosion with chemicals is another
 alternative but is  generally  unacceptable because (1) chemical costs are
 high,  (2)  the improvement is  only temporary, and (3) the chemicals seal the
 surface and prevent moisture  penetration.

 Water  Relationships—
     When an  area of land surface is  disturbed, it follows that surface
 water  patterns  are  also disturbed.  Where the disturbance goes deeply be-
 neath  the land  surface, ground  water  patterns may also be disturbed.  Of par-
 ticular concern in  reclamation  is the availability of water to support plant
 growth.   This water must  come from precipitation, ground water, or be
 supplied  by irrigation.

     The  fact that  spoils are in piles limits their ability to retain rain-
 fall unless the piles are graded to provide catchment basins and terraces.
 In addition,  spoils may weather rapidly to clay or clayey materials which
 resist  water  infiltration.  The result is likely to be that most precipita-
 tion will  become runoff and not only  fail to provide water for vegetation but
 also erode the  piles of spoil.   This  is unsightly and keeps the surface from
 achieving  the stability necessary for successful reclamation.   In addition,
 the runoff water is likely  to carry with it suspended particles and soluble
 salts  that pollute  receiving  streams.

     Normal open-pit mining practices seek to minimize the large spoil piles
 and abandoned pits  by backfilling mined-out pits.  Topsoil replaced on the
 backfill will likely not  be over about 0.3 meter in thickness  and beneath it
 will be the unconsolidated  spoil as described above.  Thus the layer of top-
 soil may have nearly all  of the water holding capacity and this will not be
 sufficient to sustain vegetation for  very long.  These areas and the spoil
 piles,  also with a  layer  of topsoil, may require irrigation for several
 years before  plants can sustain themselves.

     There are  practices  in the grading of spoils which can help with water
management and  conservation.  The forming of catchment basins  and terraces
 to hold water on the spoils will increase the amount of runoff available to
 the plants  as well  as  decrease  water  erosion.  Another practice which has
apparently been ignored is  to establish a planned slope direction or aspect.
 It has  been determined that vegetation on a north-facing slope requires only
about half  the  amount  of  applied water as that on a south-facing slope.
Water requirements  of  horizontal surfaces and east and west slopes are about
intermediate  between those of the north and south slopes.  This relates to
the angle  of  incidence of the sun and thus the soil temperature.  Grading
spoils  so  as  to  leave  long north slopes should make water use as efficient
                                      45

-------
 as possible and reduce the length of time that irrigation is required to
 establish  the vegetation.

 Final Mining Pit

      Open-pit mining leaves a hole in the ground when operations cease even
 though the mine is backfilled throughout its operation.   The alternative
 would be to place the spoils generated by the opening of the mine back into
 this final pit.  Likely this could be done only if the shape and position  of
 the orebody made it possible to plan the mine so that the final  pit was next
 to the original spoil pile.   Even then, if the mine has  operated for  a
 number of years, the value received by digging up spoils which have become
 stabilized and probably vegetated is questionable.

      The final pit must be considered in abandoning a mine and,  unless
 handled properly,  it will constitute a hazard to both people and wildlife.
 The remaining  highwalls should be graded so  that the sides can be walked up
 and down without danger to wildlife,  livestock,  or  humans.   Even in semiarid
 areas,  an open-pit mine will  probably intercept  aquifers and the abandoned
 pit will  fill  with water  to  some depth which will depend upon the hydrostatic
 head  in the aquifer.

      In a semiarid area,  as  is the case where many  uranium ore deposits are
 located,  the resulting  small  lake could be an asset as a source  of drinking
 water for domestic animals and wildlife if the water is  not  contaminated.   It
 would be  extremely attractive to these  animals and,  as stated above, would  be
 hazardous to them  unless  properly graded to  minimize the  danger  of drowning.
 Even when a pit has been  properly graded,  it will likely  take some time for
 the banks to stabilize.   Erosion of  the banks by  rainfall  and sloughing off
 of materials softened by  wetting from the  standing water may result.  To
 minimize  this,  the banks  should  be planted to soil-holding vegetation,
 preferably  grass,  and then monitored  until establishment  is  successful.

 Tailing Ponds

     The  tailings  themselves  should be  of  little or  no concern in a discus-
 sion of reclamation because they should  be completely stabilized and covered
with up to 0.6 m (2 feet)  of  soil when milling operations cease.   Great care
 is taken  in the design, preparation,  and management  of tailings ponds to
prevent radioactive liquids and  radon air emissions  from being released to
 the environment.

     The actual area to be reclaimed will be  larger  than the pond itself
because an adjoining area will have to be scraped to provide the soil cover
for the pond.  Such a scraped area, in a semiarid environment, is extremely
difficult to reclaim because the newly exposed surface lacks  the
characteristics of a developed soil.  Reclamation of these areas  will
encounter the same problems as spoil piles.
                                      46

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 STABILIZATION

 Spoils

      The digging  and  piling  of mine overburden usually leaves fine-textured
 and  easily eroded materials  on the surface and, at the same time, allows
 these materials to dry  out.  These piles are thus subject to wind erosion.
 They are also subject to water erosion because the materials are
 unconsolidated and because natural drainage channels no longer exist.

 Tailings

      The objective in stabilizing tailings is different from that of spoils
 and  thus the  methods  to be used  are likely to be different.  With tailings,
 the  concern is the escape of radioactivity while, with mine spoils, stability
 must be  achieved  to permit vegetation to become established.

      Tests have been  made of various chemical treatments for sealing the
 surface  of tailings primarily to prevent wind erosion.  A study was con-
 ducted by the Bureau  of Mines, Salt Lake City Metallurgy Research Center on
 tailings at Tuba  City,  Arizona.(19)  Materials used were an elastomeric
 polymer  and a calcium lignosulfonate.  These were sprayed on the dried ponds
 as aqueous  solutions  where they  formed crusts which were strong enough to
 prevent  wind  erosion  and which,  upon drying, were insoluble in water.  The
 persistence of these  crusts  needs to be evaluated.  The direct cost of
 materials and their application  was about $827 per hectare ($335 per acre)
 in 1969,  while the cost to cover tailings with soil and rock at other loca-
 tions was from $2,717 to $12,350 per hectare ($1100 to $5000 per acre).
 Reclamation of the tailings  area of Exxon's Highland Mine, upon cessation
 of operations, was projected in  1973 at $2,470 per hectare ($1000 per acre).
 This will include  allowing the free water to evaporate and covering the
 surface  with  0.6 meter  (2 feet)  of soil into which sufficient limestone has
 been mixed  to  neutralize acid which may move up into the plant root zone.
 The  area will  be planted to  grasses with medium rooting depths which will
 utilize  most  of the depth of the soil covering but not extend into
 the  tailings.

 REVEGETATION

     The  usual concept, a valid one, is that revegetatioii of a disturbed area
will be most  successful by using plant species that are indigenous to the
 immediate area.  These  species are at least adapted to the climate, elevation,
 and insolation level.

     Problems  emerge  in two  specific areas having to do with revegetation.
The first  is  the frequent (in the past, total) lack of advance planning for
 future uses of the  reclaimed land.  The usual assumption is that the
 premine  productivity  can be  restored by planting the same species that were
 there before mining and this becomes the reclamation program.  Such a program
 ignores  the fact that the soil and water conditions and relationships will be
                                      47

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 so  disrupted  by  the mining  activity  that these same species may not now be
 adapted  and they may  not  even  survive the new conditions.  In the semiarid
 areas  of the  country, particularly the southwest deserts, restoration of
 premine  conditions is a restoration  of range to a low level of productivity.
 A specific problem area is  that of management of plant species suitable for
 reclamation.   Indigenous  plant species should be the most successfully
 established.   However, many of the desirable plant species are poor or
 unreliable seed  producers,  they are  slow to become established, they
 produce  low yields, and they do not  respond well to management.

     Normal soil, even in dry climates, has a high population of soil fauna
 and microorganisms which are necessary for plant growth.  These organisms
 break down organic matter so that it can be recycled as plant nutrients and
 they also mix and aerate the soil surface.   In the stripping operation, the
 overburden materials are so mixed and inverted that there is little chance
 of a viable population of the soil-born organisms remaining.   Even when the
 original topsoil is stockpiled, these organisms are likely to die out in all
but the  surface of the stockpile.   The result is that when the topsoil is
 spread over the graded spoils,  the soil organism populations may be lacking
or so greatly reduced that normal soil functions are greatly delayed.

     The spoils may quickly become inoculated with the microorganisms
 (fungi, bacteria) from their being carried by the wind from surrounding
areas;  however, the re-introduction of soil invertebrates may be quite slow.

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                                  REFERENCES
  (1)  Battelle-Pacific Northwest Laboratories.  Assessment of Uranium and
      Thorium Resources in the United States and the Effect of Policy
      Alternatives.  Final Report to the National Science Foundation.
      December 1974.

  (2)  A. P. Butler, Jr., "Uranium", Geologic Atlas of the Rocky Mountain
      Region, Rocky Mountain Assoc. of Geologists, Denver, Co., pp 315-317,
      1972.

  (3)  "Uranium Recovery From Phosphoric Acid Nears Reality as a Commercial
      Uranium Source", E/MJ, December 1975.

  (4)  R. C. Merrit, The Extractive Metallurgy of Uranium, Colorado School of
      Mines Research Institute, Golden, Colorado, 1971.

  (5)  D. A. Clark, State of the Art:  Uranium Mining, Milling, and Refining
      Industry.  EPA-660/2-74-038, U. S. EPA.  NERC, Corvallis, Oregon.
      June 1974.

  (6)  Battelle's Columbus Laboratories.  Environmental Analysis Concerning
      Exploration for Uranium and Possible Resultant Mining and Milling
      Operations on the Navajo Indian Reservation, San Juan County, New
      Mexico.  Final Report to Exxon Company.  April 1975.

  (7)  "Developers Eye Texas Potential for In-Situ Uranium Leaching", E/MJ,
      July 1975.

  (8)  "In-Situ Leaching Opens New Uranium Reserves in Texas", E/MJ,
      July 1975.

  (9)  "Wyoming Uranium Miners Set Sights on Higher Production", E/MJ,
      December 1975.

(10)  Atomic Energy Commission Report to Exxon Company.   "Environmental
      Impact Statement on the Highland Uranium Mill".  Docket No.  40-8102.
      March 1973.

(11)  U. S. Environmental Protection Agency, Region VI,  Dallas, Texas.
      September,  1975.   Impact of Uranium Mining and Milling on Water
      Quality in the Grants Mineral Belt, New Mexico.  EPA 906/9-75-002.
      188 p.

(12)  U. S. Atomic Energy Commission, Directorate of Licensing.  Fuels and
      Materials.   April,  1974.   Environmental Survey of  the Uranium Fuel
      Cycle.   WASH-1248.   Various paging.

                                      49

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 (13)   Supplemental Environmental Report, Operating License Stage.  November,
       1971.  Rio Algom Corp., Moab, Utah.  Docket 408084-2.  331 p.

 (14)  U. S. Environmental Protection Agency, Office of Radiation Programs,
      Field Operations Division.  Washington, D.C. Oct., 1973.  Environmental
      Analysis of the Uranium Fuel Cycle, Part I - Fuel Supply.  Various
      paging.

 (15)  New Solution Cuts Uranium Mining Costs.  1975.  Chemical Week 17(26):
      28-29.

 (16)  W. E. Sigler, W. T. Helm, J. W. Angelovic, D.  W. Linn, and S. S. Martin.
      Dec., 1966.  The Effects of Uranium Mill Wastes on Stream Biota.  Utah
      Agricultural Experiment Station, Utah State University, Logan, Utah.
      Bull. 462,  76 p.

 (17)  J. B. Anderson, E.  C.  Tsivoglu, and S.  D.  Shearer.   1975.  Effects of
      Uranium Mill Wastes on Biological Fauna of the Animal River
      (Colorado-New Mexico), pp 373-383.   In:  Radioecology, V. Schultz and
      A. W. Klement,  Jr., eds.  Rheinhold Publishing  Co.,  New York.   746 p.

(18)  U. S.  Atomic Energy Commission, Directorate of Licensing, Fuels and
      Materials.   1974.   Final  Environmental  Statement related to the Utah
      International,  Inc.  Shirley Basin Uranium Mill, Shirley Basin,
      Wyoming.  Docket No.  40-6622.   Various  paging.

(19)  Havens,  R.  and  K.  C. Dean,  Chemical Stabilization of  the Uranium
      Tailings  at Tuba City, Arizona, U.  S. Department of Interior, Bureau
      of Mines, R.  I.  7288,  1969.
                                      50

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
 1. REPORT NO.
  EPA-600/7-76-036
             3. RECIPIENT'S ACCESSION-NO.
 4. TITLE AND SUBTITLE
  ASSESSMENT  OF ENVIRONMENTAL ASPECTS OF URANIUM MINING
  AND MILLING
             5. REPORT DATE
               December 1976 issuing date
             6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
 A. K. Reed, H.  C. Meeks,  S. E. Pomeroy, and V. Q. Hale
             8. PERFORMING ORGANIZATION REPORT NO.
 9. PERFORMING ORGANIZATION NAME AND ADDRESS
 Battelle Columbus  Laboratories
 505 King Avenue
 Columbus, Ohio   43201
             10. PROGRAM ELEMENT NO.

               EHE-623
             11. CONTRACT/GRANT NO.

                68-02-1323, Task 51
 12. SPONSORING AGENCY NAME AND ADDRESS
 Industrial Environmental Research Laboratory - Gin., OH
 Office of Research  and  Development
 U. S. Environmental Protection Agency
 Cincinnati, Ohio  45268
             13. TYPE OF REPORT AND PERIOD COVERED
               Final 2/12/76 - 7/7/76
             14. SPONSORING AGENCY CODE

               EPA/600/12
 15. SUPPLEMENTARY NOTES
 is. ABSTRACT This research program was initiated with  the  basic objective of making a pre-
 liminary assessment of  the potential environmental  impacts  associated with the mining
 and milling of domestic uranium ores.  All forms  of pollution except radiation were
 considered.

      The program included a review of the characteristics and locations of domestic
 uranium ore reserves and a review of the conventional methods for mining and milling
 these ores.  Potential  environmental impacts associated with the entire cycle from
 exploration and mining  to recovery and production of yellowcake are identified and
 discussed.  Land reclamation aspects are also discussed.

      The methods currently used for production of yellowcake were divided into four
 categories - open pit mining-acid leach process,  underground mining-acid leach process,
 underground mining-alkaline leach process, and in-situ  mining.   These are discussed
 from the standpoint of  typical active mills which were  visited  during the program.
 Flowsheets showing specific environmental impacts for each  category are provided.

      It was generally concluded that the use of tailings ponds  and deep well injection
 to  dispose of the more  toxic chemical wastes represent  the  major impacts which should
 be  considered in future environmental studies.—___	
 7.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                              b.lDENTIFIERS/OPEN ENDtD TERMS C.  COSATI Field/Group
 *Surface Mining, Underground Mining
 *Waste Treatment, *Waste  Disposal, *Mine
 Water, *Seepage, *Stabilization, Research
 and Development, Surface  Water, Underground
 Water, Industrial Plants
*Mining Wastes,  *Leach-
ability of  Solids,
Physical Upgrading,
Suspended Solids,
Revegetation.
05A
05B
05C
05D
05E
08G
13B
 3. DISTRIBUTION STATEMENT

 Release to the Public
19. SECURITY CLASS (ThisReport)
Unclassified	
21. NO. OF PAGES
       59
                                              20. SECURITY CLASS (Thispage)

                                              Unclassified
                                                                         22. PRICE
EPA Form 2220-1 (9-73)
                                            51
                                                    .& U.S. GOVERNMENT PRINTING OFFICE:1977-757-056/5554 Region No. 5-I I

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