Environmental Damage and Public Health Risks

From Uranium Mining in the American West

March 2012

Nuclear Fuel’s Dirty Beginnings

Authors

Geoffrey H. Fettus

Matthew G. McKinzie

Natural Resources Defense Council
PAGE 2 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Executive Summary

Uranium mining anywhere poses significant environmental, economic, and social risks. 

In the high plains, Rocky Mountains, and intermountain West, however, where water 

resources are already scarce, it is inevitable that water-intensive uranium extraction 

poses significant risks to the region’s environmental and public health. Nonetheless, domestic 

and international mining companies are showing renewed interest in recovering uranium that 

lies beneath the iconic landscapes and fragile ecosystems of the American West. Projections of 

a U.S. and global “nuclear renaissance” have sparked forecasts of a uranium supply shortfall and 

rising uranium prices, spurred by the prospect of significant public subsidies for new nuclear 

power generation, and ultimately prompting a flood of uranium mining claims and applications 

for exploration permits in water-limited states such as Colorado and Utah. The vast majority of 

proposed uranium mines are “in-situ leach” (ISL) solution mines, which typically use large wellfields of hundreds of wells, diesel-powered pumps, and huge volumes of groundwater to dissolve 

the uranium from the ore bearing rock and bring it to the surface. 

This development is cause for concern, given that during 

earlier uranium mining booms—spurred by construction 

of tens of thousands of nuclear weapons and more than 

a hundred nuclear power plants during the Cold War—

uranium mining and milling practices were not regulated in 

any meaningful way. In fact, it was not until the late 1970s 

and early 1980s that Congress, the Nuclear Regulatory 

Commission (NRC) and the Environmental Protection 

Agency (EPA), finally instituted a legal and regulatory 

framework to address the environmental and public health 

impacts of uranium milling. That effort, however, resulted 

in a splintered patchwork of controls that has remained 

largely ineffective. Furthermore, the federal government has 

never regulated conventional mining (i.e., underground and 

open pit) since exempting production of uranium ore from 

licensing in the Atomic Energy Act of 1961. Consequently, 

uranium extraction in the American West has left behind 

a tainted legacy of serious damage to the environment 

and human health. Many of the communities affected by 

uranium recovery have been disproportionately low-income 

or minority populations, representative of an all too common 

pattern of environmental and economic injustice with 

respect to resource extraction. 

The question examined in this report is whether current 

controls on both conventional hard-rock mining and milling, 

and alternative solution-mining techniques for uranium 

recovery, are sufficient to prevent a new round of harms to 

the natural resources and communities of this region, which 

is already being heavily exploited for the extraction of oil, 

natural gas, coal, coal-bed methane, and now shale-gas. 

The combined impacts of uranium mining alongside these 

extraction techniques in the American West have remained 
PAGE 3 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Credit TK

Figure 1: Radiation hazard sign at Crow Butte in-situ leach mining 

facility in Nebraska. Source: Owe Aku, Lakota Media Project, 

February 2010.

unexamined and unaddressed at the state and federal level. 

In response, this report will also examine the cumulative 

impacts, where the long-term impairment of freshwater 

aquifers is a major concern, compounded by population 

growth, prolonged dry weather conditions, and severe 

competition for water resources. 

In-Situ Leach Uranium Mining

Since ISL technology was first used in the early 1960s, 

the uranium mining industry has touted the process as 

noninvasive and environmentally friendly.1

 Preliminary 

analysis of publically available information—commissioned 

by Natural Resources Defense Council (NRDC)—however, 

indicates that:

1) Comprehensive federal analysis of ISL environmental 

impacts is lacking

2) ISL uranium mining entails an increased risk of 

radioactive and heavy metal contamination to land, 

air, and most significantly, underground water systems 

(aquifers)

Our research and analysis reveal that despite a clear 

legal obligation under the National Environmental Policy 

Act (NEPA) to analyze the long-term cumulative effects of 

sacrificing aquifers to uranium mining and other forms of 

resource extraction, the NRC and its sister federal agencies, 

such as the Department of the Interior’s Bureau of Land 

Management (BLM), have failed to study these cumulative 

impacts. Moreover, there is a distinct unwillingness or 

lack of resources on the part of the federal regulators to 

collect and analyze what data do exist, despite relevant 

legal requirements and a clear obligation not to repeat 

the mistakes of the past. Hence, information on original 

groundwater quality and potential future uses is insufficient, 

or simply absent, from any wider regulatory understanding of 

the American West’s future need. 

Consequently, federal decision-makers such as the NRC, 

and other federal and state agencies engaged in licensing, 

permitting, and leasing the use of lands and groundwater, 

lack a comprehensive understanding of the cumulative 

and connected environmental impacts of federal actions to 

facilitate and regulate the vast array of extractive industries 

that are sapping the sustainability of groundwater and other 

critical natural resources in the American West. 

This lack of understanding has led to uranium extraction 

projects that cause irreparable environmental devastation. 

NRDC’s research reveals that 62 out of the 100 current and 

prospective ISL mining sites fall within western counties for 

which “high” or “extreme” risks of water sustainability are 

predicted by mid-century (see Table 4 and Figure 19). At 

these sites, the groundwater chemistry has been or could be 

contaminated to the point that the aquifer is degraded and 

lost to other beneficial uses over a long term. Unfortunately, 

hope for remediation of the groundwater at these sites is 

minimal, as previous efforts to restore water to pre-mining 

quality have proven to be expensive, with the process lasting 

longer than originally scheduled and yet still failing, especially 

for contaminants such as uranium or radium, both of which 

have well-documented adverse human health effects.

The neglect of uranium mining impacts by federal research 

and analysis can be attributed to the flawed framework 

responsible for regulating resource extraction. The NRC 

and the EPA share jurisdiction for ISL mining regulation, 

with the NRC serving as the primary licensing body, 

applying environmental standards for uranium recovery 

set by the EPA. These regulatory standards are both faulty 

and outdated. Federal and state regulations for uranium 

milling—or hard rock uranium recovery—have not been 

updated for more than two decades and do not match today’s 

scientific understanding of the impact that radiation and 

heavy metals have on the environment and public health. 

Furthermore, this regulatory framework was designed to 

address conventional uranium milling—not unconventional 

techniques, such as ISL mining, likely to comprise the 

majority of new uranium recovery sites in the next decade. 

Regulations promulgated in the late 1970s and 1980s did 

not contemplate ISL mining and its associated harms, and 

the legal framework that currently governs ISL mining is 

wholly inadequate to the task of protecting scarce western 

groundwater resources. This regulatory negligence must be 

rectified if the nation is to avoid future risks to the public 

health and environment. Simply updating regulations for 

conventional milling would solve only part of the problem 

the nation faces going forward into a new round of domestic 

uranium mining and milling. 

Both the EPA and the NRC should move swiftly to update 

the relevant environmental protections for uranium recovery. 

The sooner improved standards can be put into effect, the 

sooner public health and the environment will be protected. 

The EPA, to its credit, has commenced a revision of its health 

and environmental protection standards for uranium and 

thorium mill tailings.2

 Apparently content with the statusquo until the EPA issues new standards, the NRC has yet to 
PAGE 4 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

move forward with reforming its own regulations. In fact, 

for several years the NRC has declined to publish a draft 

groundwater protection rule for ISL facilities. As of now, the 

EPA still has not issued even a draft set of more protective 

regulations.3

 Immediately after the EPA issues its draft 

rulemaking, the NRC should commence work on its own ISL 

rulemaking proceeding that conforms to the EPA’s proposed 

standards. Until that time, NRDC supports a moratorium 

on the review and granting of any new ISL uranium mining 

licenses. 

Moreover, the NRC should defer action on any new 

application for a uranium recovery license until there is 

federal adoption of key elements of Colorado’s 2008 Land 

and Water Stewardship Act, which requires substantially 

more stringent protections than currently exist. Also, the 

White House Council on Environmental Quality (CEQ) 

should undertake a full inter-agency review of the cumulative 

and connected impacts of all current federal programs and 

proposed agency actions to facilitate and regulate extraction of 

mineral and fossil-energy resources in the arid West, including, 

but not limited to, the NRC’s program to license new uranium 

recovery operations. The CEQ review should address: 

n	 Long and short-term environmental impacts on critical 

natural resources, such as groundwater, air-quality, 

animal habitat, and vegetation, along with reasonable 

alternatives that might better protect these resources. 

The environmental review effort should include 

participation across federal agencies. 

n	 Impacts on national parks and other protected areas 

where U.S. uranium mining has been concentrated, in 

the vicinity of the four corners region. 

n	 The reasonable alternative of continuing primary 

reliance on the global uranium market, which for more 

than two decades has proven to be a dependable and 

economical source of uranium for US reactors. 

n	 Reasonable alternatives for meeting the national purpose 

and need for these resources—including uranium—

by identifying technology alternatives that are less 

environmentally destructive or can substitute partially or 

entirely for the proposed natural resources extraction. 

n	 Economic and social impacts before U.S. states and 

communities are asked to accept a significant risk of 

impairment to their scarce groundwater resources in 

return for fleeting economic gains. 

In addition, states should take the initiative by enacting 

stronger environmental, public health, and taxpayer 

protections that address the harms of uranium recovery. 

Whether an agreement state—one that has assumed NRC’s 

regulatory authority over uranium recovery—or one that 

has separate authority to regulate conventional uranium 

mining—states should pass strong laws that seek to limit 

the environmental harms inflicted by uranium recovery and 

protect the economic interests of the state by requiring that 

uranium mining companies post adequate cleanup bonds.4

Optimistically, in the face of federal inaction, some states are 

already implementing stricter regulations and enforcement 

around uranium recovery. For example:

n	 Colorado has passed the first protective state law that 

directly addresses the environmental impacts of both 

conventional and ISL mining methods

n	 South Dakota has rejected, for the second time, a new ISL 

mine’s Underground Injection Control Permit application 

due to inadequate and conflicting information 

n	 Wyoming commenced more vigorous enforcement and 

levied fines against an ISL operator for falling far behind 

in implementing groundwater restoration obligations as 

stated in its mining permits

n	 The Navajo nation enacted a ban on any type of uranium 

mining and processing on Navajo territory until past 

harms have been remediated

Recommendations

In sum, it is critical to avoid repeating past regulatory 

negligence when licensing new uranium mills and mines. 

There are still some 4,000 abandoned uranium mines 

scattered across the landscape of the West, and decades after 

the closure of operations, a significant number remain to 

be cleaned up.5

 A full accounting of the costs and the path 

forward has only just started after decades of neglect. The 

costs of what cleanup has been done—a price-tag that is 

certainly in the hundreds of millions of dollars—has been 

borne in large part by taxpayers rather than the mining 

companies and downstream customers of the uranium 

products. 

The relevant federal and state agencies must update 

the existing regulatory structure for both conventional 

and unconventional uranium recovery to reflect the best 

available scientific data and analysis of the environmental 

impact and long-term public health risks. The EPA is moving 

forward on this front, and the NRC should join the EPA 

in a collaborative effort to protect the environment from 

the impacts of renewed and possibly greatly expanded 

uranium recovery in areas with scarce and even diminishing 

groundwater resources. In parallel with this effort, the CEQ 

should initiate a broad NEPA review of the cumulative 

and connected environmental impacts of all current and 

proposed Federal programs that facilitate or regulate the 

extraction of fossil-energy and mineral resources in the 

American West, including uranium recovery operations 

regulated by the NRC. For the interim, further licensing of 

uranium recovery operations should be deferred until fully 

protective environmental standards and an effective system 

of regulatory enforcement are in place.
PAGE 5 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

I. Uranium Mining in the United States: 

A Historical and Legal overview

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U.S. Annual Uranium Prouction (million lbs. U3O8)

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ISL 

Figure 2: Historical U.S. uranium production after World War II. Sources: U.S. Department of Energy/

Energy Information Administration, eia.doe.gov/cneaf/nuclear/dupr/usummary.html; Uranium Energy 

Corporation, uraniumenergy.com/uranium/usup/. 

To gain a greater perspective of how and why future uranium mining projects pose a threat 

to environmental and public health, it is important to have the historical context of 

uranium mining in the western United States. 

Most U.S. mining activity has been susceptible to boomand-bust cycles. Uranium is no exception. The first boom 

came in the late 1950s to fuel the nation’s nuclear weapons 

stockpile; production of uranium oxide soared from 5.56 

million pounds in 1955 to 35.28 million pounds in 1960. 

Another boom in the late 1970s, corresponding to the rapid 

initial build-out of nuclear power plants, brought production 

to a record 43.70 million pounds in 1980. Each of these 

booms was followed by plummeting uranium prices and left 

a landscape of thousands of abandoned mines sprinkled 

across the western United States.11 Figure 2 provides details 

on historical U.S. uranium production; it also illustrates the 

increase in production from in-situ leach (ISL) operations in 

the past decade, relative to conventional mining operations. 

The launch of the nation’s effort to make an atom bomb—

the Manhattan Project—during World War II triggered 
PAGE 6 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Figure 4: Uranium production sites (past and present), occurrences, 

and prospects in the western United States, from the USGS Mineral 

Resources Data System. A uranium occurrence is a locality where 

uranium has been found. A prospect is an occurrence that has been 

developed, for example by subsurface drilling, to determine the 

extent of mineralization.

Figure 3: The EPA’s Uranium Location Database (ULD) contains 

records for approximately 15,000 uranium mines in the United 

States, 4,000 of which had documented production between the 

1940s and 1990s. Mine location information was collected by the 

EPA from federal, state, and tribal agency sources. The majority 

of mines having uranium as the primary commodity are located in 

Colorado, Utah, Wyoming, New Mexico, and Arizona, typically on 

federal or tribal lands.

high demand for uranium as a critical material for nuclear 

weapons. This spurred the creation of a U.S. government 

procurement program that actively supported uranium 

exploration until 1970, primarily in the Four Corners region 

of the American Southwest, an area comprising Colorado, 

Utah, Arizona, and New Mexico.12,13 Significant production 

continued until the mid-1980s, when demand declined and 

uranium-producing facilities began to close.14 Figures 3 and 4 

show the geographical distribution of uranium in the United 

States using EPA and U.S. Geological Survey (USGS) data, 

respectively. 

A Brief History of Conventional

Uranium Mining Regulation

Most uranium mining and milling sites were operated 

and managed under a minimal public health and safety 

regulatory regime that had only recently been implemented. 

The Nuclear Regulatory Commission (NRC) regulates all 

commercial entities, operations, and facilities that work with 

anything “nuclear,” including uranium, otherwise referred to 

(along with the element thorium) as “source material” under 

the foundational law, the Atomic Energy Act of 1954 (AEA).15

They are called source materials because when subjected 

to further processing or neutron bombardment in a reactor, 

they are the source for “fissile materials” (plutonium and 

U233, respectively) suitable for use in either nuclear explosives 

or nuclear reactors. Uranium that is highly enriched in the 

isotope U235 can support an explosive chain reaction when 

rapidly assembled in sufficient mass, while natural uranium 

and uranium enriched at levels under 20 percent U235 are 

usable in power reactors. The NRC has regulatory jurisdiction 

over these source materials when their concentration in 

mined ores equals or exceeds 0.05 percent by weight. 

The AEA requires that a person or company obtain an NRC 

license to transfer or receive in interstate commerce any 

source material “after removal from its place in nature.”16 The 

NRC understood this particular section of the law (Section 

62 of the Act) as precluding jurisdiction over conventional 

uranium mining but as establishing its jurisdiction over 

the milling of uranium. The AEA left the thousands of 

conventional uranium mines that dot the western landscape 

essentially unregulated for decades. The ongoing cleanup 

of those mines (from tiny underground operations to large 

open-pit surface mines) is a direct consequence of this 

lack of regulation.17 This somewhat counterintuitive state 

of affairs dates back 50 years and means that the NRC 

regulates facilities that concentrate, extract, chemically 

Note: All map figures cannot be 

edited in their current format.
PAGE 7 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

process, isotopically enrich, or fabricate uranium, but not the 

conventional mines that remove the uranium ores that are 

the source of feed materials for such facilities. However, ISL 

mines recover uranium from the underground ore body in a 

manner that is somewhat analogous to the way aboveground 

uranium mills concentrate uranium from crushed ores. 

Therefore, the NRC legally regards ISL mines (i.e., well fields 

and associated processing operations) as “uranium recovery” 

facilities over which it has regulatory jurisdiction.

The AEA’s limiting of the NRC’s jurisdiction to stages 

of uranium processing that occur after ores are removed 

from their place in nature left several regulatory gaps that 

remained unaddressed, except in the most piecemeal 

fashion. Over time, conventional uranium mining operations 

were gradually regulated under various laws, including the 

Safe Drinking Water Act (SDWA), the Clean Water Act (CWA), 

the Clean Air Act (CAA), and state mining laws, and thus 

came under the purview of the EPA and delegated state 

authorities. But even then, problems of application persist 

that are beyond the scope of this report. 

The CWA, to take one example, covers only those 

radioactive discharges that do not fall into the “source, byproduct, and special nuclear material” category.18 Uranium 

is a source material. Radon or other radionuclides that exist 

in a tailings pile are a by-product material. And while there 

are now SDWA limitations that can be enforced, the extent 

to which a citizen or state can use tools like the CWA to 

address the harms of conventional uranium mining remains 

complicated and expensive.

In 1946, when Congress passed the AEA and created the 

Atomic Energy Commission (AEC), it made the federal 

government the sole purchasing agent for domestically 

produced uranium.19 The AEC set fixed prices for uranium 

and, in an effort to spur the nascent nuclear industry and its 

domestic suppliers, provided incentives such as roads and 

buying stations.20 With a focus almost entirely on production 

and growth, the AEC allowed the uranium mining industry 

to operate without serious environmental or public health 

supervision. Uranium prospectors would file claims for 

potential sites and usually adjacent areas. Ownership of 

these claims was (and still is) regulated according to the 1872 

Mining Law and is enforced by the U.S. Department of the 

Interior (DOI).

In open-pit mining, one or more pits are excavated to 

expose the uranium deposit. In the 1950s these pits tended 

to be small, covering a few acres. More recently, open-pit 

mines have covered hundreds to thousands of acres; the 

Jackpile Mine on Laguna Pueblo in New Mexico consumed 

about 3,000 acres. The overburden (that is, the unwanted 

material overlying the uranium deposit) is moved to a nearby 

mine-waste area, and dikes and ditches are often constructed 

around these waste piles to collect precipitation runoff and 

divert it to sedimentation ponds. The piles and associated 

sediment-laden ponds contain radioactive residues and other 

hazardous materials.21 Waste piles, low-grade ore piles, and 

mine-water settling ponds also typify surface facilities at large 

underground mining complexes. Oxidation of mine wastes 

in both cases releases soluble hexavalent (+6) uranium, 

radionuclides, and heavy metals to surrounding soils and 

surface water courses.

Mill tailings—waste created from the extraction of uranium 

concentrate, or yellowcake (U3

08), from mineralized ores—

contain all of the radiological and heavy metal contaminants 

indigenous to the ore, plus the acids or strong bases and 

organic compounds used to leach the uranium from the rock. 

Mill tailings are fine-grained sands that retain 99 percent of 

the ore’s original radioactivity.22 At some closed mills, efforts 

to stabilize tailings piles were ineffective or simply negligent, 

and tailings material was subsequently spread by wind and 

water erosion to adjacent lands and communities. All 52 

inactive and active uranium mill tailings piles, most of which 

were created before federal regulations were adopted in the 

early 1980s, are unlined and the source of extensive localized 

groundwater contamination. The removal and use of mill 

tailings as construction material also resulted in extensive 

local surface contamination.23

The environmental and public health damage from 

decades of essentially unregulated conventional uranium 

milling precipitated the Uranium Mill Tailings Remediation 

Control Act (UMTRCA) of 1978 (Public Law 95-604).24

UMTRCA Title I established authority for the Uranium 

Mill Tailings Remedial Action (UMTRA) Project, in which 

Congress directed the Department of Energy (DOE) to clean 

up 22 radioactively and chemically contaminated uranium 

mill tailings sites (all pre-1978) and the nearby areas into 

which contamination had spread. UMTRCA Title II gave 

the NRC authority to regulate “active” uranium milling 

and tailings disposal at 26 uranium mills licensed in 1978. 

As stated previously, regulations adopted by the NRC in 

the 1980s for control of conventional mill tailings during 

and after operations are still applied by NRC to ISL/ISR 

operations today.

The milling sites alone have cost the federal government 

(and thus the taxpayer) billions of dollars in cleanup costs.25

And while cleanup programs have been ongoing for decades, 

a handful of sites have been addressed only within the last 

few years. The EPA’s Technologically Enhanced Naturally 

Occurring Radioactive Materials (TENORM) report estimated 

$2.27 billion in cleanup costs just for the uranium mills (i.e., 

not including the legacy costs of cleaning up and stanching 

the flow of contamination from conventional mine sites).26 At 

locations in Wyoming, Nebraska, and New Mexico where the 

NRC is overseeing the cleanup of mills or ISL sites, estimates 

exist for approximately half the sites and add up to more than 

$80 million.27 At other sites where NRC Agreement States, 

such as Texas, Colorado, and Utah have direct oversight 

authority over cleanup, estimated costs or completion dates 

have not yet been determined.

Turning to conventional mines, the EPA estimates the 

average cost of closure at nearly $14 million per mine. 

When the costs for the Midnite Mine in Washington and the 

Northeast Church Rock Mine in New Mexico are added, the 

average cost will probably increase substantially. The EPA 

has identified more than 520 abandoned uranium mines on 

Navajo land alone, with the cleanup cost likely to reach into 

the hundreds of millions of dollars.28
PAGE 8 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

$0 

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Figure 5: Uranium (U3O8) weighted average price, 1980 to 2010. Source: EURATOM Supply Agency Annual Report 

2010, Annex 3: ESA average prices for natural uranium, ec.europa.eu/euratom/ar/last.pdf.

Prospects for New Mines: 

Conventional and In-Situ Leach

For the past 20 years, the production of uranium in the 

United States has been relatively low, but the historic boomand-bust cycle has shown signs of a possible recurrence.29 In 

2007 the Environmental Working Group used information 

collected by the Bureau of Land Management (BLM) and 

found that in just four states (Colorado, New Mexico, 

Utah, and Wyoming), uranium claims had surged from an 

estimated 4,300 staked in fiscal year 2004 to more than 32,000 

in fiscal year 2006.30

NRDC ascribes much of this recent speculative claim 

activity to an anticipated uranium supply shortfall and a 

short-term spike in the price of uranium that has since largely 

receded. Because uranium is not traded on a commodity 

exchange that records the executed prices of all transactions, 

uranium prices are negotiated directly between individual 

buyers and sellers, and the terms of many transactions 

remain confidential. Two uranium market consulting firms 

track these transactions and regularly publish “indicative” 

prices for both long-term uranium supply contracts and shortterm single delivery sales on the spot market, which typically 

accounts for less than 15 percent of total uranium sales. 

In the decade from 2000 to 2010, prices for uranium 

ballooned and then dropped again. Rising demand beginning 

in 2003 prompted a modest increase in production in the 

United States. And while the World Nuclear Association 

(WNA) in 2007 reported that market forces were bringing new 

uranium projects into production, the timetables of planned 

uranium projects often change with fluctuations in uranium’s 

price. In the summer of 2007, the immediate cash purchase 

price, or spot price, briefly rose to an historic high of $137 

per pound of uranium oxide (U3

O8) , but then fell by more 

than two-thirds by May 2010, when it fell to just above $40 

per pound.31

Figure 5 shows the weighted (by size of transaction) average 

annual spot prices and multiannual (long-term negotiated 

contract) prices for U3

O8 since 1980 for nuclear utilities in 

the European Union, where a long-term data set for both 

spot market transactions and long-term contract prices is 

publicly available. The figure shows that long-term contract 

prices, reflecting the vast bulk of all uranium sales by weight, 

fluctuate within a much narrower range than do spot prices. 

Figure 6, compiled from multiple sources by the 

International Panel on Fissile Materials (IPFM), shows the 

average constant-dollar price paid per kilogram of uranium 

by U.S. reactor operators over nearly 40 years.32 

The chart reveals no secular trend toward permanently 

higher prices for uranium, suggesting that U.S. uranium 

mining areas with economically marginal deposits of lowgrade ore will remain vulnerable to short-term swings in the 

uranium market. As of August 1, 2011, the spot price indicator 

for uranium (U3

O8) was approximately $52.25 per pound 

($115.20 per kilogram).33

While the sharp run-up in uranium prices of 2007 and 2008 

has largely receded, the future extent of growth in uranium 

demand and mine output remains unclear. A significant 

fraction of the existing U.S. demand was met in the past 

decade from Russia’s surplus weapons uranium stockpile. But 

with this arrangement scheduled to end in 2013, and with 

demand likely to grow in Asia as nuclear power expands in 
PAGE 9 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

350

300

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1970 1975 1980 1985 1990 1995 2000 2005 2010

Uranium Price ($2006/kgU)

Spot market price

Average paid by US reactor operators

Figure 6: Uranium spot price and average price paid by U.S. reactor operators, 

1971 to 2009. Source: IPFM, 2010. Need more info

Table 1: Number of operating uranium mines in the United States for 2007, 2008, and 2009 by mine type, and total 

uranium production. 

Number of Mines Operated 2007 2008 2009

Underground 6 10 14

Open Pit 0 0 0

In-Situ Leach 5 6 4

Other* 1 1 2

Total Mine Production (thousand pounds U3

O8) 4,541 3,879 4,145

“Includes sources of uranium from mine water, mill site cleanup and mill tailings, and well-field restoration. Source: U.S. DOE/EIA.

China, East Asia, and India—even after the Japanese nuclear 

disaster—some uranium investors predict a tightening 

supply and steadily rising uranium prices in the near future.34

NRDC does not necessarily agree with the rising uranium 

price scenario, given the shaky nature of the “nuclear 

renaissance” and the likelihood that the new sources of 

mined uranium will enter a market priced at around $50 

per pound for uranium concentrate. Certainly from the 

perspective of the United States, it is unclear how extensively 

our own domestic uranium industry will be revived. A 2010 

report by the Massachusetts Institute of Technology (MIT) 

concluded that uranium resources recoverable at or under 

$130 per kilogram ($50 per pound) would likely total on 

the order of 13 million tons. Given current global nuclear 

capacity of 377 gigawatts electric (GWe), an assumed future 

global nuclear capacity utilization of 85 percent (historically 

this figure has been lower), and uranium consumption 

averaging 200 metric tons per GWe per year, then this 13 

million tons of relatively cheap uranium would last for 

about 200 years. Alternatively, it could support a doubling 

of global nuclear capacity for 100 years. In other words, 

beyond intervals of 5 to 10 years in which global uranium 

mining capacity might temporarily fail to keep pace with the 

addition of new reactor capacity, there is no reason to expect 

a longterm dramatic rise in the price of uranium to begin 

anytime soon. Therefore a bonanza for western states with 

uranium resources appears unlikely.35

From a domestic perspective, during the 1960s, 1970s, and 

early 1980s, U.S. uranium mines could and did produce more 

than 35 million pounds of uranium per year. By contrast, 

between 1993 and 2009, U.S. uranium production averaged 

only 3.9 million pounds per year.36 Since the first mines were 

dug in the 1940s, New Mexico has always been among the 

top uranium-producing states. Recently, Texas and Wyoming 

have produced the most uranium, although overall uranium 

production is significantly below historical highs.37
PAGE 10 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Due to the rapid growth of large ISL mining operations in 

Kazakhstan, ISL mining now accounts for 41 percent of global 

uranium production, followed by conventional underground 

mining at 28 percent, open-pit mining at 25 percent, and 

“by-product” mining (i.e., the production of uranium in 

conjunction with the mining of other minerals, such as 

copper or phosphates) at 5 percent.38 Nonetheless, in the 

United States, conventional underground mines produced 

more uranium concentrate than did ISL operations between 

2007 and 2009 (Table 1).39 While thousands of claims have 

been filed, it is unclear how many are seriously being pursued 

despite the resources available.40

The forecast of a nuclear renaissance has led to interest in 

siting new uranium mines and associated facilities in areas 

both within and outside the traditional mining regions of 

the U.S. West.41 The number of working ISL operations has 

fluctuated as the volatility of uranium prices has pushed 

facilities in and out of production. In 1982 there were 18 

facilities. That number was down to four by 1992 and to two 

by 2003. In 2009 only four ISL mines were in operation, but 

approximately 45 ISL projects—two-thirds of which are in 

Wyoming—are now in the planning stages. The number will 

remain a moving target as the price of uranium rises and falls.

Apart from these plans, roughly 55 properties are 

considered uranium deposits amenable to ISL mining, 

with approximately half of them in Wyoming and others in 

Arizona, New Mexico, and Texas.42 Table 2 provides a list of 

operating, planned, potential, and closed ISL operations 

in the United States; these are mapped in Figures 7 and 8. 

These 125 ISL operations fall within eight states: Arizona 

(9 potential), Colorado (3 planned), Montana (1 planned), 

Nebraska (1 operating and 5 planned), New Mexico (4 

planned and 6 potential), South Dakota (1 planned), Texas 

(5 operating, 3 planned, 12 potential, and 12 closed), and 

Wyoming (6 operating, 28 planned, 27 potential, and 2 closed). 

(Table 2 Continued) NRDC ISL Mine Database of in-situ leach mines and facilities: operational, planned, potential, and closed.

In-Situ Leach Site Status Corporate State County

Alta Mesa Operational Mestena Uranium LLC Texas Brooks

Crow Butte Operational Cameco Corp. Nebraska Dawes

Christensen Ranch Operational Uranium One USA, Inc.

Hobson Operational South Texas Mining Venture Texas Karnes

Kingsville Dome Operational (in standby) Uranium Resources Inc. Texas Kleberg

Irigaray Ranch Operational Uranium One USA, Inc. Wyoming

Johnson

La Palangana Operational South Texas Mining Venture Texas Duval

Rosita Operational (in standby) Uranium Resources Inc. Texas Duval

Smith Ranch ISL Wellfield Operational Cameco Corp. Wyoming Converse

Smith Ranch ISL Satellite Facility SR-1 Operational Cameco Corp. Wyoming Converse

Smith Ranch—Highland Ranch ISL 

Satellite No. 2 Operational Cameco Corp. Wyoming Converse

Smith Ranch—Highland Ranch ISL 

Satellite No. 3 Operational Cameco Corp. Wyoming Converse

Smith Ranch Central Processing Plant 

(CPP) Operational Cameco Corp. Wyoming Converse

Allemand-Ross (Satellite)—Bear Creek Planned (Expansion) Uranium One Wyoming Converse

Allemand-Ross (Satellite)—Sand Draw Planned (Expansion) Uranium One Wyoming Converse

Alzada Planned Bayswater Uranium Corp. Montana Carter

Antelope Planned (Developing/

Application in Review) Uranium One Wyoming Sweetwater 

and Fremont

Antelope—Jab Planned (Developing/

Application in Review) Uranium One Wyoming Sweetwater

Antelope—Sheep Mountain Planned (Developing/

Application in Review) Uranium One Wyoming Sweetwater

Antelope—Twin Butte Planned (Developing/

Application in Review) Uranium One Wyoming Sweetwater 

Bison Basin Project Planned WildHorse Energy Wyoming Sweetwater

Centennial Project, Powertech Project 

near Fort Collins—North Zone Planned Powertech Uranium Corp. Colorado Weld

Table 2: NRDC ISL Mine Database of in-situ leach mines and facilities: operational, planned, potential, and closed.
PAGE 11 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

(Table 2 Continued) NRDC ISL Mine Database of in-situ leach mines and facilities: operational, planned, potential, and closed.

In-Situ Leach Site Status Corporate State County

Centennial Project, Powertech Project 

near Fort Collins—South Zone Planned Powertech Uranium Corp. Colorado Weld

Church Rock Planned Hydro Resources, Inc./ 

Strathmore Mineral Corp. 

New 

Mexico McKinley

Crow Butte—North Trend Planned (Expansion, 

Application Received)

Cameco (Crow Butte 

Resources, Inc.) Nebraska Dawes

Crow Butte—Marsland Planned (Expansion) Cameco (Crow Butte 

Resources, Inc.) Nebraska Dawes

Crow Butte—Three Crow Planned (Expansion) Cameco (Crow Butte 

Resources, Inc.) Nebraska Dawes

Crownpoint Planned (Partially Permitted 

and Licensed)

Hydro Resources, Inc./ 

Uranium Resources Inc.

New 

Mexico McKinley

Crownpoint Section 19/29 Planned (Licensed) Hydro Resources, Inc./

NZ Uranium LLC

New 

Mexico McKinley

Dewey—Burdock Planned (Application in Review) Powertech Uranium Corp. South 

Dakota

Custer and 

Fall River

Gas Hills Uranium Mining District Planned (Under Construction) Strathmore Mineral Corp. Wyoming Fremont

Goliad Uranium Planned (Partially Permitted 

and Licensed) Uranium Energy Corp. Texas Goliad

Hank Planned (Application in Review) Cameco Corp. Wyoming Campbell

Jane Dough Planned (Application Expected 

2012) Uranerz Energy Wyoming Johnson

La Palangana Planned (Permitted and 

Licensed)

Uranium Energy Corp./

Uranium One Texas Duval

Last Chance #3 and #4 Planned (Application in Review) Nuvemco LLC Colorado Montrose

Lost Creek Planned (Expansion, 

Application Received)

Ur-Energy USA, Inc./Lost 

Creek ISR LLC Wyoming Sweetwater

Lost Soldier Planned (Expansion) Ur-Energy USA, Inc. Wyoming Sweetwater

Ludeman Planned (Expansion) Uranium One Wyoming Converse

Marsland (Satellite) Planned (Expansion) Cameco Corp. Nebraska Dawes

Moore Ranch Extraction Site (Planned) Application Complete for 

Moore Ranch

Uranium One Americas, Inc./

Energy Metals Wyoming Campbell 

Nichols Ranch ISR Project Planned (Application in Review) Cameco Corp./Uranium 

Energy Corp. Wyoming Johnson

North Butte/Brown Ranch Uranium 

Deposit Planned Cameco Corp. Wyoming Campbell

North Trend (Satellite) Planned (Expansion) Cameco Corp. Nebraska Dawes

Pine Tree Planned Strathmore Mineral Corp. Wyoming Campbell

Reno Creek Planned Strathmore Mineral Corp. Wyoming Campbell

Reynolds Ranch (Satellite) Planned (Licensed) Cameco Corp. Wyoming Converse

Ross Planned Strata Energy, Inc. Wyoming OshotoCrook County

Ruby Ranch Planned (Expansion) Cameco (Power Resources, 

Inc.) Wyoming Campbell 

County

Ruth Planned (Licensed) Power Resources, Inc. Wyoming Johnson

Ruth Uranium Deposit Planned Cameco Corp. Wyoming Johnson

Smith Ranch ISL (Satellite No. 1) Planned Cameco Corp. Wyoming Converse

Smith Ranch ISL Satellite Facility SR-2 

(Proposed) Planned (Expansion) Cameco Corp. Wyoming Converse
PAGE 12 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

(Table 2 Continued) NRDC ISL Mine Database of in-situ leach mines and facilities: operational, planned, potential, and closed.

In-Situ Leach Site Status Corporate State County

Smith Ranch/Highland CPP Planned (Expansion) Cameco (Power Resources, 

Inc.) Wyoming Converse

Southwest Reno Creek Planned Strathmore Mineral Corp. Wyoming Campbell

Sweetwater Uranium Project Planned Rio Tinto Energy America Wyoming Sweetwater

West Alkalai Creek Planned Wildhorse Energy Wyoming Fremont

Aladdin Potential (Deposit) Powertech Uranium Corp. Wyoming Cook

Bootheel Planned Target Exploration & Mining 

Corp. Wyoming Albany

Buck Point Potential (Deposit) Target Exploration & Mining 

Corp. Wyoming Albany

Buckaroo Flats Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Burnt Wagon Potential (Deposit) Uranium Energy Corp. Wyoming Natrona

C de Baca Potential (Deposit) Max Resource Corp. New 

Mexico Socorro

C-Line Potential (Deposit) Cameco Corp. Wyoming Campbell

Collins Draw Potential (Deposit) Cameco Corp. Wyoming Campbell

Converse Potential (Deposit) New Horizons Wyoming Converse

Coon Creek Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Cyclone Rim Potential (Deposit) Cameco Corp. Wyoming Sweetwater

Dalton Pass Potential (Deposit) Strathmore Mineral Corp. New 

Mexico McKinley 

Dewey Terrace Potential (Deposit) Powertech Uranium Corp. Wyoming Weston and 

Niobrara

Doughstick Potential (Deposit) Cameco Corp. Wyoming Campbell

Eagle Potential (Deposit) Cameco Corp. Wyoming Sweetwater

East Nichols Potential (Deposit) Cameco Corp. Wyoming Campbell

Elkhorn Potential (Deposit) Bayswater Uranium Corp. Wyoming Crook 

Gas Hills Planned Cameco Corp. Wyoming Fremont

Hosta Butte Potential (Deposit) NZ Uranium LLC New 

Mexico McKinley 

Middle Mountain Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Niles Ranch Potential (Deposit) Cameco Corp. Wyoming Campbell

North Nichols Potential (Deposit) Cameco Corp. Wyoming Johnson 

North Reno Potential (Deposit) Cameco Corp. Wyoming Campbell

North Rolling Pin Potential (Deposit) Cameco Corp. Wyoming Campbell

Oak Creek Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Pendleton Mesa Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Peterson Potential (Deposit) Uranium One Wyoming Converse

Red Bluff Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Sand Creek Potential (Deposit) New Horizons Wyoming Converse

Shirley Basin Potential (Deposit) Strathmore Mineral Corp. Wyoming Carbon

Sky Potential (Deposit) Strathmore Mineral Corp. Wyoming Fremont

Suckerite Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Swinney Switch Potential (Deposit) Uranium One Texas Live Oak and 

Bee

Taylor Ranch Potential (Deposit) Cameco Corp. Wyoming Campbell
PAGE 13 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

(Table 2 Continued) NRDC ISL Mine Database of in-situ leach mines and facilities: operational, planned, potential, and closed.

In-Situ Leach Site Status Corporate State County

Treeline Potential (Deposit) Western Uranium Corp. New 

Mexico

McKinley and 

Cibola 

Turnercrest Potential (Deposit) Magnum Minerals USA Wyoming Campbell

Verna Ann Potential (Deposit) Cameco Corp. Wyoming Campbell

West North Butte Potential (Deposit) Cameco Corp. Wyoming Campbell

Willow Creek Planned, Application Received Uranium One Wyoming Campbell

Workman North Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Workman South Potential (Deposit) Rodinia Minerals Inc. Arizona Gila

Texas RRC Uranium Exploration 

Permit Number 118C Exploration Permit URI, Inc. Texas Duval

Texas RRC Uranium Exploration 

Permit Number 121C Exploration Permit URI, Inc. Texas Kleberg

Texas RRC Uranium Exploration 

Permit Number 122C Exploration Permit URI, Inc. Texas Duval

Texas RRC Uranium Exploration 

Permit Number: 124E Exploration Permit South Texas Mining Venture Texas Duval

Texas RRC Uranium Exploration 

Permit Number 125C-1 Exploration Permit Mestena Texas Brooks and 

Jim Hogg

Texas RRC Uranium Exploration 

Permit Number 134C Exploration Permit Signal Equities, LLC Texas Atascosa

Texas RRC Uranium Exploration 

Permit Number 135C Exploration Permit Signal Equities, LLC Texas Live Oak

Texas RRC Uranium Exploration 

Permit Number 136B Exploration Permit Uranerz Energy Corp. Texas Briscoe

Texas RRC Uranium Exploration 

Permit Number 137B Exploration Permit Signal Equities, LLC Texas Bee

Texas RRC Uranium Exploration 

Permit Number 141A Exploration Permit Uranium Energy Corp. Texas Karnes

Texas RRC Uranium Exploration 

Permit Number 142 Exploration Permit Uranium Energy Corp. Texas Goliad

Texas RRC Uranium Exploration 

Permit Number 143 Exploration Permit Signal Equities, LLC Texas Live Oak

Benavides Closed (Reclamation) Uranium Resources Inc. Texas Duval

Bruni Closed Areva NC Texas Duval

Burns Ranch/Clay West Closed (Reclamation) USX (U.S. Steel) Texas Live Oak

Christensen Ranch Closed (Changing License to 

Operational) Areva NC Wyoming Johnson

El Mesquite Closed (Reclamation) Areva NC Texas Duval 

Holiday Closed (Reclamation) Areva NC Texas Duval 

Irigaray Closed (Reclamation) Areva NC Wyoming Johnson

Lamprecht/Zamzow Closed (Reclamation) Intercontinental Energy Texas

Las Palmas Closed (Reclamation) Everest Minerals Texas Duval

Mt. Lucas Closed (Reclamation) Everest Minerals Texas Live Oak

O’Hern Closed (Reclamation) Areva NC Texas Webb

Tex-1 Closed (Reclamation) Everest Minerals Texas xx missing 

info

Vasquez Closed (Reclamation) Uranium Resources Inc. Texas Duval

West Cole Closed (Reclamation) Areva NC Texas Duval and 

Webb

Sources: U.S. Environmental Protection Agency, U.S. Nuclear Regulatory Commission, U.S. Geological Survey,and specific license applications and 

environmental review documents.
PAGE 14 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Figure 7: NRDC In-Situ Leach Mine Database operational, planned, 

and potential facilities for Wyoming and adjacent states. 

Figure 8: NRDC In-Situ Leach Mine Database of in-situ leach mines: 

planned and potential facilities for New Mexico and adjacent states.

Worldwide Uranium Resources and

Potential Domestic Impact

About 62 percent of the world’s annual mined uranium 

production in 2010 came from the three largest suppliers—

Kazakhstan (33 percent), Canada (18 percent), and Australia 

(11 percent). The world uranium production and recoverable 

reserve data are shown in Table 3. For the past five years, 

U.S. nuclear power-reactor operators have purchased only 

about 15 percent of their needed uranium from domestic 

sources.43 Worldwide identified uranium reserves, as 

reported by the Organization for Economic Co-operation and 

Development (OECD), show that in 2007 the United States 

had approximately 6 percent (342,000 tons) of the world’s 

uranium reserves. None of these resources, however, falls into 

the lowest cost-of-recovery category for uranium (less than 

$18 per pound), under which 642,000 tons of world reserves 

fall. These and other factors make it difficult for American 

producers to compete in the world market.44

Looking forward, uranium production in the United 

States and elsewhere will be determined by nuclear energy 

development and the global uranium market. Uranium for 

nuclear energy is supplied not only from primary sources 

like mining operations but also from secondary sources of 

already mined and processed uranium, such as the blending 

down of highly enriched uranium from weapons programs 

and the blending up of uranium enrichment tailings. In 2010 Figure 9: NRDC In-Situ Leach Mine Database operational, planned, 

and potential facilities for the Texas coastal plain.
PAGE 15 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

uranium from mine production met 78 percent of the world’s 

requirements for nuclear power, with the rest supplied by 

former weapons materials.45 

It is NRDC’s sense that there could be a measured increase 

in global demand for mined uranium due to the termination 

of the Russian-U.S. Megatons to Megawatts program and the 

continued growth of nuclear power in Asia. Whether there 

will be significant growth in demand in the United States and 

Europe looks much less certain, especially after the events 

of the Fukushima nuclear disaster in Japan. A key factor will 

be whether future supplies of mined uranium outside the 

United States will be sufficient to keep the moving average 

of uranium prices consistently below $35 to $45 per pound, 

which we understand to be roughly the price range required 

Table 3: World uranium production and recoverable resource statistics by country. 

Country 2010 Production from 

Mines (tonnes uranium)

Percent of World 

Production

2007 Known Recoverable 

Resources of Uranium (tonnes 

uranium)

Percent Total 

Resources

Kazakhstan 17,803 33.17 817,000 14.94%

Canada 9,783 18.23 423,000 7.73%

Australia 5,900 11.00 1,243,000 22.73%

Namibia 4,496 8.37 275,000 5.03%

Niger 4,198 7.82 546,000 9.98%

Russia 3,562 6.63 274,000 5.01%

Uzbekistan 2,400 4.47 111,000 2.03%

USA 1,660 3.09 342,000 6.25%

Ukraine (est.) 850 1.58 200,000 3.66%

China 827 1.54 68,000 1.24%

Malawi 670 1.24 N/A N/A

South Africa 583 1.08 435,000 7.95%

India 400 0.74 73,000 1.33%

Czech Republic 254 0.47 N/A N/A

Brazil 148 0.27 278,000 5.08%

Romania (est.) 77 0.14 N/A N/A

Pakistan (est.) 45 0.08 N/A N/A

France 7 0.01 N/A N/A

Jordan N/A N/A 112,000 2.05%

Mongolia N/A N/A 62,000 1.13%

Other Countries N/A N/A 210,000 3.84%

World Total 53,663 5,469,000

Sources: World Nuclear Association Market Report data at world-nuclear.org/info/inf23.html and, the Organisation for Economic Co-operation and 

Development (OECD), the Nuclear Energy Agency (NEA), and the International Atomic Energy Agency (IAEA), Uranium 2007: Resources, Production 

and Demand (the “Red Book”). 

for profitable operation of most ISL recovery projects. 

As shown in Figure 10, annual employment in the U.S. 

uranium mining industry is minimal, barely topping 1,000 

person-years in all related activities, including post-mining 

reclamation. 

Unless the United States envisions selling its uranium 

abroad to fuel Chinese and other foreign reactors–thereby 

defeating the “energy security” rationale for expanding 

domestic uranium production46–growth prospects for the 

U.S. uranium industry are tied either to underpricing and 

thereby replacing current uranium imports, or to competing 

effectively to satisfy projected increases in U.S. nuclear 

fuel demand. On that score, according to the U.S. Energy 

Information Administration (EIA), the prospect of a nuclear 
PAGE 16 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

renaissance in the United States is fading. The latest 2011 

EIA “reference case” projection is for U.S. nuclear power 

capacity to grow from 101 GWe in 2009 to only 110.5 GWe 

in 2035. Under an “economy-wide” greenhouse gas pricing 

scenario in which there is an increase in the cost of fossil 

fuel alternatives, considered politically unlikely in the near 

term, the projected U.S. nuclear capacity in 2035 would be 

130 GWe, a gradual 30 percent increase phased in over 25 

years.47 These are not scenarios that necessarily lead to sharp 

2004 2005 2006 2007 2008 2009 2010

1600

1400

1200

1000

800

600

400

200

0

Exploration

Mining

Milling and Processing

Reclamation

Figure 10: Uranium production industry employment in the United States, by 

category, 2004 to 2010. Source: U.S. Energy Information Adminstration, Form EIA851A, “Domestic Uranium Production Report” (2004-2010).

increases in uranium prices or domestic mining industry 

employment over the next decade. 

Such modest potential economic gains from expanded 

uranium mining must be weighed against future mine 

cleanup costs; the potential costs of impairment to 

groundwater resources and real estate values; the potential 

to contaminate other valuable mineral deposits; and the 

potential damage to future agricultural, residential, and 

recreational uses of the land. 
PAGE 17 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Although this report focuses largely on ISL mining and the need for regulatory reform, it 

is essential before proceeding further to have a basic understanding of the conventional 

uranium mining process and the legacy left by uranium mining and milling. 

II. Conventional Uranium Recovery: 

Environmental and Health Impacts

The Mining Process

Fundamentally, uranium in its dispersed natural state is 

a common, mildly radioactive, heavy element that exists in 

low concentrations in soil, rock, and water. For its primary 

uses in atomic weapons and nuclear power plants, uraniumbearing ore must be mined from the earth and then milled, or 

concentrated.

Uranium has generally been mined in one of four ways, 

depending on the depth and ore grade of the uranium 

deposit and the associated geology; these methods are 

surface mining, conventional underground mining, and heap 

leach mining. Each extraction technique has broad impacts 

on the human and natural environment. 

Conventional Mining

n	 Surface mining, or open-pit mining, resembles strip 

mining for coal in the eastern United States. It is, quite 

simply, the surface removal of soil and rock overburden 

and extraction of ore that contains uranium. Scrapers, 

mechanical shovels, and trucks rip or blast free about 30 

times as much topsoil and overburden as actual uranium 

ore. Once the ore body is exposed, it is excavated and 

hauled out of the pit for processing. The material left 

over after processing, called uranium tailings, is both 

radioactive and toxic.

n	 Underground mining techniques are used if the 

uranium ore is located deeper in the bedrock. This 

process involves extracting ore deposits through deep 

shafts and drifts (horizontal tunnels extending from 

the shafts). Trains, conveyor belts, elevators, trucks, or 

diesel-powered heavy equipment bring the mined ore 

to the surface and arrange it by grade in piles near the 

mine surface installation. It is then trucked to a mill 

where it goes through a series of processes to become 

uranium yellowcake. The non-uranium-grade ore that is 

brought to the surface is placed in waste-rock-specific 

dumps.While underground mining leaves much of the 

non-mine-grade ore in place and therefore creates less 

overburden and waste rock than does surface mining, 

it exposes underground workers to the highest levels of 

radon gas of any method. It also produces radioactive 

waste rock.

Heap Leach Mining

The third method, called heap leach mining, involves treating 

crushed ore on the surface with a wash of chemicals to 

extract uranium. Heap leaching was used on an experimental 

basis in the United States during the 1970s and 1980s, and 

the few sites where it was used in this country are now being 

decommissioned. There are, however, at least two sites—one 

in Wyoming and one in New Mexico—that have submitted 

letters of intent to present license applications to the NRC.48 

Uranium Milling

After uranium ore is removed from land, it must be milled 

in order to separate the usable portions of uranium oxide 

(typically less than 1 percent of the material) from the 

waste rock. At a uranium mill, ore is first crushed and 

ground in order to enable further processing. Next, water 

or some other lixiviant—the leaching fluid or solution 

used to recover the uranium from the ore—is added in 

order to facilitate movement, reduce dust, and begin the 

leaching process.49 The slurry generated through this 

process is then pumped into tanks for leaching.50 In this 

way, the lixiviant becomes impregnated with uranium. 
PAGE 18 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Sampling Crushing

Grinding

Leaching

Sodium Chlorate

Classifiers (Washing)

Tailings

Thickeners

Tailings

Stripping Circuit

Salt Solution

Extraction Circuit

Ammonia Precipitation Filtration

Drying

Packaging

Yellow Cake

Ore Delivered

Su from the mine lfuric Acid

Tailings Pile

Wet

Dry

 Source: Energy Information Administration, Office of Coal, Nuclear, Electric and Alternate Fuels.

The uranium is separated from the lixiviant to become 

yellowcake, a uranium oxide (U3

O8) in either liquid or powder 

form; then it is placed in barrels and shipped to conversion 

and enrichment plants where it is fabricated into fuel for 

electricity production or nuclear weapons.51 Figure 11 above 

from the Energy Department provides a basic graphic 

representation of the processes. 

The Environmental Impacts

The environmental hazards from uranium recovery 

operations are real and widespread. Overall, open-pit and 

underground mining bring to the surface ore that bears 

significant concentrations of naturally occurring radioactive 

elements and potentially toxic heavy metals—materials 

that would otherwise have remained distributed and 

undisturbed within the earth’s crust. The wastes from openpit mining are extensive and have proved complicated to 

control over time. The primary environmental burden from 

open-pit mining has, of course, been management of the 

huge amounts of radioactive waste residues, or tailings, that 

uranium mills generate.52

Only a small fraction of the mined material contains the 

valuable uranium oxide; approximately one to five pounds 

are extracted from each ton of ore. The tailings from the 

milling process are normally dumped as sludge into special 

piles. In the past, these piles were abandoned and posed (and 

in some instances continue to pose) serious threats to public 

health and safety. The expediently engineered structures 

to contain the tailings have eroded over time and allowed 

radioactive waste to leak into the surrounding ecosystem,53

fouling nearby groundwater and surface water and exposing 

entire communities to dangerous levels of radioactivity. The 

largest such piles in the United States and Canada contain 

up to 30 million tons of solid material.54 Figure 12 is an aerial 

photograph of a producing conventional uranium mine in 

Utah, and Figure 13 is a satellite image of the only currently 

operating uranium mill in the United States. 

The hazards from just one mine or incident can be 

significant and long lasting.55 For instance, in the 1979 collapse 

of a tailings dam in Church Rock, New Mexico, 93 million 

gallons of radioactive and chemically contaminated liquid 

and 1,100 tons of solid radioactive tailings were deposited into 

the Rio Puerco, contaminating the river more than 60 miles 

downstream.56 There are thousands of uranium mines in the 

western United States in need of remediation. Cleanup of 

conventional mines is, for the most part, happening under the 

Comprehensive Environmental Response, Compensation, and 

Liability Act, better known as Superfund.57

For decades the Navajo Nation has been especially affected 

by boom-and-bust uranium mining. On Navajo land alone, 

nearly four million tons of uranium ore were extracted from 

1944 to 1986; left behind were more than 500 abandoned 

uranium mines, four inactive uranium milling sites, a former 

dump site, and the widespread contamination of land and 

water.58 Only recently has the government attempted to 

assess and mitigate this contamination, but full reclamation 

of the land is unlikely.59

An additional consequence of uranium mining has been 

skyrocketing lung cancer rates among the estimated 3,000 

to 5,000 Navajo who worked the mines, contributed to by 

the inhalation of ore dust.60,61 Given the long history and the 

severity of uranium impacts on the Navajo people, in 2005 the 

Navajo Nation banned uranium mining and processing on 

Navajo lands until past harms have been fully remediated.62

Figure 11: Schematic of the uranium milling process. Source: EIA, U.S. Department of Energy, “Decommissioning of U.S. 

Uranium Production Facilities,” February 1995. 
PAGE 19 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

In a 2007 statement before Congress, a senior representative 

of the Navajo Nation stated: 

Uranium mining and milling on and near the 

reservation has been a disaster for the Navajo people. 

The Department of the Interior has been in the 

pocket of the uranium industry, favoring its interests 

and breaching its trust duties to Navajo mineral 

owners. We are still undergoing what appears to 

be a never-ending federal experiment to see how 

much devastation can be endured by a people and 

a society from exposure to radiation in the air, in 

the water, in mines, and on the surface of the land. 

We are unwilling to be the subjects of that ongoing 

experiment any longer.63

Like the cleanup of abandoned mines, the remediation of 

processing (milling) facilities that dot the American West is 

extensive. For example, the 700-acre Uravan site in Montrose 

County, Colorado, began operating as a radium-recovery 

plant in 1912. From the early 1930s to the 1980s, the site 

Figure 12: Aerial photograph of the Pandora uranium mine in San 

Juan County, Utah, owned by Denison Mines. Pandora is accessed 

by spiral tunnels, or declines, from the surface and is connected 

underground with the adjacent Beaver mine, 1.5 kilometers northwest 

of Pandora and not visible here. Pandora, a mature conventional 

uranium mine with extensive underground workings, produced 

52,000 tons of ore in 2008. Source: Google Earth.

Figure 13: Satellite image of the Denison Mines’ White Mesa 

facility—the Satellite image of Denison Mines’ White Mesa facility, 

the only conventional uranium mill currently operating in the United 

States. White Mesa uses sulfuric acid leaching to extract and recover 

uranium (as well as vanadium as a by-product). It is licensed to 

process and produce eight million pounds of U3O8 per year. 

Source: Google Earth.

was home to a uranium and vanadium processing facility. 

More than 10 million cubic yards of solid wastes containing 

radioactive elements, metals, and inorganic compounds 

were left at the site. Liquid wastes from seepage totaled more 

than 350 million gallons at the end of 2004. Contaminants 

included radioactive products such as raffinates (liquid 

wastes from the uranium processing operations), raffinate 

crystals (primarily ammonium sulfate compounds), and mill 

tailings containing uranium and radium. Other chemicals 

in the tailings and groundwater included heavy metals 

(lead, arsenic, cadmium, and vanadium), thorium, and 

residual salts. The EPA listed the site on Superfund’s National 

Priorities List (NPL) in 1986.64 Cleanup has taken decades, 

and the project is finally nearing closure. The extent of the 

cleanup is best described in an EPA Superfund document: 

Under the Consent Decree, Umetco [the owner] was 

required to complete the following general remedial activities 

as specified in the RAP [Remedial Action Plan], as amended:

n	 Remove and clean up dispersed materials and 

contaminated soil from approximately 400 acres.
PAGE 20 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

n	 Relocate more than 3 million cubic yards of mill wastes 

and contaminated materials to secure repositories on 

Club Mesa.

n	 Construct waste and tailing repository covers, liquid 

evaporation and retention ponds and permanent runoff 

control structures, utilizing more than 1.7 million cubic 

yards of earthen materials.

n	 Construct five double-lined ponds (totaling 40 acres) for 

the evaporation of hillside seepage, tailing pile seepage 

and extracted groundwater.

n	 Construct and use a new repository in the “B-Plant” area 

capable of disposing in excess of 1.8 million cubic yards of 

evaporative pond demolition debris and radioactive waste. 

n	 Demolish and remove about 50 major mill facility 

structures and buildings, including the process systems 

and circuits, and remove over 260 buildings in the town 

of Uravan.

n	 Collect over 70 million gallons of hillside and tailing 

seepage, containing approximately 6,000 tons of 

contaminated inorganic compounds. Hillside and tailing 

seepage that was collected was transferred to Club Ranch 

Ponds for management by evaporation.

n	 Extract approximately 245 million gallons of 

contaminated liquids from the groundwater with the 

removal of approximately 14,500 tons of contaminated 

inorganic compounds. Contaminated groundwater that 

was collected was transferred to Club Ranch Ponds for 

management by evaporation.65

Noteworthy is the EPA’s demand that 260 buildings be 

demolished because tailings were used as a construction 

material, a public health hazard in extremis.66

In sum, conventional mining and milling practices 

for military and civilian purposes left an extensive 

environmental legacy of radioactive and heavy metals 

pollution in the western United States and Canada. There 

have been several thorough assessments of this legacy, and 

we provide a short listing of some of the most useful 

in endnote 1.
PAGE 21 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

With the environmental and public health legacy of conventional uranium mining 

and milling in mind, it is critical to review the in-situ leach (ISL) mining process and 

examine: (1) whether current regulations are able to prevent the known harms of ISL 

mining and mitigate its other negative impacts; and (2) whether the environmental consequences 

of ISL uranium mining, particularly on ground aquifers, are sufficiently understood. 

III: In-Situ Leach Mining: The Environmental

Impacts and the Failure of the NRC

Environmental Review Process

The ISL Uranium Mining Process

In 1957 the mining industry began experimenting with ISL 

methods to recover uranium from low-grade ore in Wyoming. 

Early experimenting was simple: “They mixed up the sulfuric 

acid solution and just dumped it on the ground, and soaked 

it through the material and collected it in a little trench 

at the end.”67 With some technological advancement, the 

method proved successful at recovering lower-grade uranium 

ore at greater depths than was possible using traditional 

underground or pit mining.

Because ISL has been the generally cheaper way to mine 

moderate- to low-quality uranium deposits since the mid 

1970s, developing new ISL mines has been preferred over 

developing new traditional surface mines and underground 

mines in the United States.68 Of the new domestic uranium 

mines and expansion projects under consideration in the 

United States for the near term, the majority will be ISL. But 

even as domestic uranium recovery has moved away from 

conventional methods and toward ISL mining, worldwide 

there remains more conventional uranium mining.69

ISL combines the mining and milling processes by 

leaching uranium and other heavy metals off the surface of 

the host rock deep underground in the aquifer. The process, 

however, is used only when the source rocks (ore) meet 

certain conditions. 

n	 The ore is too deep for traditional mining to be economical.

n	 The uranium is present in multilayered “roll front” 

deposits. Such deposits are formed when groundwater 

containing uranium moves through the subsurface 

(usually sandstone) and encounters an oxygen-deprived 

zone. When this occurs, the uranium is reduced from 

an oxidized state and precipitates out (along with other 

metals within the groundwater) to form a deposit that 

looks much like a crescent moon.70

n	 The ore body sits below the water table. Often, the 

aquifer that contains the deposits sits below an aquifer 

that is used as a source for domestic, industrial, and 

agricultural needs.71

n	 Considerable methane and hydrogen sulfide are 

associated with the ore.

n	 The ore is “low grade”—containing low amounts of 

uranium—and is too thin to be mined conventionally.

n	 The rock formation is highly permeable.72

n	 The deposit is thought to be confined above and below 

by more impermeable mudstone or shale.73

Figure 14: Schematic of the process by which uranium is deposited 

in roll-front ore bodies, as found in the Texas coastal plane. Source: 

Susan Combs, Texas Comptroller for Public Accounts, 2008.74

Uranium Roll Front
PAGE 22 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Figure 15: Overview of a portion of Cameco’s Crow Butte uranium 

in-situ leach facility in Dawes County, Nebraska. Source: Google Earth.

The ISL process involves drilling and operating hundreds 

of injection and production wells at each mining site. Mining 

the aquifer to recover uranium in this fashion changes 

the chemistry of the groundwater, with concentrations of 

uranium increased up to 100,000 times.75 Levels of other 

naturally occurring radioactive elements and heavy metals 

are increased similarly.

The method extracts uranium by injecting a solution of 

water containing an acid or base solution (in the United 

States, this is a base that usually dissolved oxygen and 

sodium bicarbonate) into a uranium-bearing rock formation 

in an underground aquifer. This solution, or lixiviant, 

dissolves the uranium (and other heavy metals) from its 

host rock. Production wells, located between the injection 

wells, intercept the “pregnant” lixiviant and pump it to the 

surface. From there, the heavy-metal-rich liquid is piped 

to a centralized ion-exchange facility, which extracts the 

uranium. The “barren” lixiviant, stripped of uranium, is 

regenerated with oxygen and carbon dioxide and recirculated 

for continued leaching. The ion exchange resin, which 

becomes loaded with uranium, is stripped (or “eluted”) of its 

uranium and returned to the well field facility. The resulting 

rich eluate is precipitated to produce yellowcake slurry. This 

slurry is dewatered and dried to a final drummed uranium 

concentrate, the raw material that, when converted to toxic 

uranium hexafluoride and heated to a gaseous state, is used 

as feed for the plants that enrich nuclear fuel. During the 

mining process, more water is produced from the ore-bearing 

formation than is reinjected. This net withdrawal, or “bleed,” 

produces a cone of depression in the water table in the 

mining area and is intended to confine the fluid flow to the 

mining zone. 

Notably, one environmental benefit of ISL mining over 

conventional forms of mining is the limited amount of solid 

waste. The EPA has identified ISL surface solid waste impacts 

as soils from site preparation; waste from drilling exploratory, 

injection, and production wells; and solids precipitated 

during the storage and processing of fluids in holding 

ponds.76 The amounts can vary widely and are tied to the 

relative size of the ISL operation. 

On the other hand, ISL operations contaminate the aquifer 

being mined, and the associated liquid waste is substantial. 

Well-field development (from the net withdrawal, or “bleed 

rate”), processing plant operations, and aquifer restoration 

activities all create liquid waste. By the industry’s own 

estimate, an average ISL mine disposes at least 13 million 

gallons in deep-well injection.77 However, the EPA, which has 

produced one of the few useful summaries of radionuclide 

data for ponds and injection wells, states that “[l]imited data 

are available on the volume of this material.”78 The NRC, as 

the primary regulator, has done little to rectify this paucity of 

data on the volumes of liquid wastes and their impacts.

The EPA is not alone in saying that the environmental 

impacts associated with ISL operations (such as the 

Figure 16: Aerial photo of the of processing plant (upper left) and 

two evaporation ponds (lower right) at Cameco’s Crow Butte uranium 

in-situ leach facility in Dawes County, Nebraska. Source: Google Earth.
PAGE 23 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

restoration process, borehole cuttings, engineered ponds, 

deep-well injection of waste materials, and burial of 

solution flow lines) are poorly documented. International 

organizations are voicing similar concerns.79 An extensive 

evaluation of these invasive activities and their effect, alone 

and in combination with other nearby resource-extraction 

activities, has not been undertaken by any of the government 

authorities that are charged with regulating the industry 

and protecting the interests of the environment and local 

communities. To highlight why this is important, later in 

this report we will explore some of the better-understood 

disruptions caused by ISL activity.

The visible footprint of ISL mining operations, as seen 

in the associated aerial photographs, illustrates the extent 

of industrial activity and the scale of potential aquifer 

contamination in the subsurface. Figures 15 and 16 display 

the infrastructure of ISL operations at Nebraska’s Crow Butte 

site, including well fields, evaporation ponds, pump houses, 

and processing facilities. Figures 17 and 18 do the same for 

Texas’s Kingsville Dome and Alta Mesa sites, respectively.

The NRC’s Environmental

Review Process

As described in the previous section, ISL mining has 

environmental impacts that have yet to be thoroughly 

Figure 17: A portion of Uranium Resources Inc.’s Kingsville Dome 

in-situ leach facility in Kleberg County, Texas. Source: Google Earth.

Figure 18: A portion of Mestena Uranium’s Alta Mesa in-situ leach 

facility in Brooks County, Texas. The processing plant is at lower left. 

Source: Google Earth.

analyzed by the NRC, the agency charged with licensing 

the operations. In theory, the NRC is supposed to conduct 

formal and thorough evaluations of the environmental 

impacts of proposed ISL mining projects, in compliance with 

the National Environmental Policy Act (NEPA). In practice, 

however, the agency has failed to do so, in part because 

of a faulty regulatory structure. Nonetheless, the NRC is 

proceeding with licensing ISL operations.

How NEPA is Supposed to Work

NEPA serves to ensure that the federal government looks 

before it leaps prior to approving any project, whether 

that project is a federal highway, an offshore oil well, or an 

ISL uranium mine. Specifically, NEPA mandates a basic 

procedural framework—a public scoping to determine the 

range of agency activities and environmental impacts that 

should be included, followed by a draft environmental impact 

statement (EIS)—to help an agency in the decision-making 

process. To comply with NEPA, a draft EIS must set forth 

the purpose of and the need for a given project, take a hard 

look at environmental impacts, assess alternatives, examine 

mitigation measures, weigh the cumulative impacts of the 

project, and, finally, solicit and consider public comment 

on all these matters. Once that has been done, the agency 

revises its draft EIS in light of the comments received from 
PAGE 24 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

the public, state and local governments, and other federal 

agencies, and then issues a final EIS that includes formal 

responses to the comments received. Only then may the 

agency move forward with its preferred alternative, whatever 

that may be. 

In most cases, citizens adversely affected by an agency’s 

decision have the right to bring suit in federal court if they 

believe the legal requirements of NEPA have not been met by 

the agency. The process for challenging the environmental 

review documents from agencies such as the Department of 

the Interior or even the Department of Energy is relatively 

straightforward. Generally, an interested party comments on 

the draft EIS and awaits the government’s response in its final 

document and associated “Response to Comments” portion 

of the EIS. If there are still points of substantial disagreement—

for example, whether the agency considered a reasonable 

alternative course of action—the commenting party may move 

to file for judicial review in Federal district court. 

How the Nuclear Regulatory 

Commission’s Environmental

Review Works

In contrast to this norm for most federal agencies, the 

NRC’s process for challenging NEPA findings is much more 

convoluted and burdensome for members of the public. 

The industry applicant subject to regulation must file 

an environmental report (ER) that essentially acts as the 

rough draft for the NRC’s draft EIS.80 The ER submission 

is contemporaneous with the license application, which 

triggers a brief window of time in which the public must 

qualify as a “party” to the licensing proceeding in order to 

challenge the conclusions of an EIS that has not yet been 

issued. Thus, a legal challenge to the agency’s compliance 

with NEPA can go forward only in the context of an individual 

licensing proceeding in which the plaintiffs have gained 

standing by having their “contentions” admitted into the 

proceeding by a “licensing board” made up of the NRC’s own 

administrative law judges. Notably, the commencement of 

licensing proceedings for ISL mines, nuclear reactors, or 

enrichment facilities (at least in every instance NRDC has 

seen) long predates the issuance of a draft EIS associated with 

the project, often by a year or more. 

How this works out in practical terms is remarkable. 

Consider the likely scenario of a member of the public who 

thinks an environmental analysis is legally inadequate 

and wants to take an agency to court. Generally speaking, 

within the framework of our legal system, the member of 

the public would simply file comments on the agency’s EIS 

and then, if necessary, file a legal challenge once the agency 

finalizes the EIS and issues a Record of Decision based on 

it. In the NRC context, however, this person is out of luck, 

as the NRC holds that any environmental challenges arising 

under NEPA must be based on the precursor ER filed by the 

applicant. This is true even though the obligations imposed 

on the applicant are contained in NRC’s regulations (10 

C.F.R § 51) and not in NEPA’s. 

If the potential objecting person has not been admitted 

as an “intervenor” in the licensing hearing and filed timely 

comments on the industry’s ER years before the arrival of the 

agency’s NEPA documents, the NRC can choose to ignore 

those comments without meaningful opportunity for judicial 

redress. This denial of due process for ordinary citizens runs 

counter to bedrock NEPA law and is currently being challenged 

in the NRC’s administrative court.81

Making the situation even more complex, the NRC 

contends that challenges to the impact statement are 

untimely if not filed shortly after the draft impact statement 

is issued and improper after the final EIS has been issued, 

unless the final impact statement contains positions not 

previously identifiable from the draft.82

A noted legal scholar on such matters, Anthony Roisman, 

succinctly describes how strange the process can become for 

the public: 

When the NRC Staff issues a draft impact statement 

under NEPA, contentions can be based on the 

draft only if it can be shown that they are based on 

information or conclusions that differ significantly 

from the information contained in the applicant's 

environmental report. However, a contention that 

challenges the applicant’s environmental report 

because it does not comply with NEPA is rejected 

because an applicant cannot be required to comply 

with NEPA. So, how does a NEPA challenge become 

a contention if the staff merely parrots what the 

applicant has said in the environmental report? 

These multiple hurdles that interveners face are 

not merely annoying, they are resource intensive 

and sap the limited resources of interveners on 

procedural issues, making it less likely they will have 

resources to address the substantive issues. Because 

they are procedural hurdles, they also challenge the 

pro se intervener, without legal assistance, to meet 

every technical requirement, each of which is “strict 

by design,” thus creating multiple opportunities for 

the applicant and NRC Staff to find a ”flaw“ in the 

intervener's pleading. This allows an applicant or NRC 

Staff to expose a procedural misstep, while avoiding 

a hearing on the substantive concerns that have 

motivated the public participation by the intervener.83

This is an untenable situation for interested members of 

the public. NEPA reviews are rendered superfluous except for 

how they relate to individual licensing proceedings, where 

members of the public can participate only at enormous cost 

in lawyers, technical experts, and time. One concrete effect 

of this regulatory structure is that NRC has managed to avoid 

assessing ISL uranium mining’s environmental impacts, 

especially in the broader context of its occurrence in the 

iconic landscapes and arid natural habitats of the western 

United States. 
PAGE 25 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

How the NuClear Regulatory 

Commission’s Generic Environmental

Impact Statement Became Problematic 

In 2007, facing new applications for ISL mines after years 

of regulatory inaction, the NRC began work on the Generic 

Environmental Impact Statement for In-Situ Leach Uranium 

Milling Facilities (hereinafter described as the GEIS). 84 The 

draft was completed in July 2008. It was followed in July 2009 

by the final GEIS and several site-specific environmental 

analyses that incorporate the larger document’s findings. 

The final GEIS should have served as a thorough review 

of environmental impacts, assessing the hazards and 

benefits of ISL mining and providing reasonable alternatives. 

Unfortunately, it failed to accomplish these goals, even 

though it was prepared in order to comply with NEPA. NRDC 

and regional public interest organizations commented on 

the GEIS during its development, but our suggestions for a 

searching review that could inform better environmental 

decision-making were disregarded. One key example is the 

way NRC altered the stated purpose of the document as it 

transitioned from draft to final form. 

Originally, the NRC intended to prepare a document that 

would “identify and evaluate the potential environmental 

impacts associated with construction, operation, aquifer 

restoration, and decommissioning of in-situ uranium 

recovery facilities.”85 NRDC and others filed extensive 

comments on this draft version and requested that the NRC, 

with its (comparatively) substantial federal resources, provide 

precisely the detailed history and thorough environmental 

assessment that had been lacking to date. When it became 

apparent that investigating, identifying, and evaluating 

alternatives to those environmental impacts was a sizable 

task, the agency issued a final GEIS that—while hardly 

differing in substance from the July 2008 draft—significantly 

restated and narrowed its purpose to avoid the detailed 

environmental evaluation it had originally promised. The 

NRC’s stated purpose for the GEIS now reads:

10 CFR Part 51 regulations require evaluating the 

environmental impacts of the ISL facility as part 

of the licensing process. Recognizing that the 

technology for ISL uranium milling is relatively 

standardized, that the applications may be 

submitted over a relatively short period of time, and 

that the potential ISL facilities would be located 

in relatively discrete regions of the western United 

States, NRC decided to prepare a GEIS to avoid 

unnecessary duplicative efforts and to identify 

environmental issues of concern to focus on in 

site-specific environmental reviews. In this way, 

NRC could increase the efficiency and consistency 

in its site-specific environmental review of license 

applications for ISL facilities and so provide an option 

for applicants to use and licensees to continue to use 

the ISL process for uranium recovery.86

NRDC and others in the public interest community did not 

agree with this response. In short, the NRC effort devolved 

from identifying and evaluating the potential environmental 

impacts associated with ISL uranium mining to one where 

the agency sought to avoid duplicative reviews and thereby 

increase the efficiency of its NEPA reviews so that industry 

could “use the ISL process.” 

The few changes that were made from the draft to the final 

were almost wholly cosmetic. The final GEIS’s “Response 

to Comments” section was devoted to the NEPA version of 

kicking the can down the road, stating repeatedly that a more 

thorough environmental review would be forthcoming in 

site-specific analyses. Sadly, those site-specific reviews have 

only produced documents that reference back to the original 

GEIS, cycling an interested reader back and forth between 

inadequate analyses.87

Technical Analysis of In-Situ

Leach Contamination of

Groundwater Aquifers

In order to improve our technical understanding of the 

impacts of ISL uranium mining and the NRC’s failed EIS 

process on groundwater aquifers, NRDC worked with 

a University of Colorado hydrogeologist, Dr. Roseanna 

Neupauer, to do some preliminary analysis and modeling of 

groundwater flow at an ISL mine.88 Dr. Neupauer chose to 

study the Christensen Ranch ISL site in Wyoming, basing her 

simulations and modeling on available data from the site’s 

1992 permit application and a pump test that was conducted 

in November of that year. She noted in her report that the 

Wyoming site was chosen for these simulations because 

of the availability of the pump test data in addition to the 

limited information available in the permit application. She 

also pointed out that the pump test data were confined to the 

southern portion of Mine Unit 2 at the Christensen Ranch, so 

she was able to make no claim as to whether the information 

was representative of the entirety of Mine Unit 2, much less 

the rest of the ISL site. Finally, Dr. Neupauer stated that “[s]

ome of the necessary data were not available, so estimates 

were made using the best available data and the judgment of 

the modeler.”89

What we learned from Dr. Neupauer buttressed our 

desire to ensure that the regulatory process for ISL mining 

be substantially improved. Specifically, she modeled ISL 

mining operations and then restoration operations including 

groundwater sweep, reverse osmosis, and recirculation, and 

predicted the groundwater and solute movement for an 

additional 20 years after completion of restoration. While we 

were somewhat comforted that her initial analysis in this one 

instance showed that the spread of contamination was likely 

to be relatively slow, her results indicate that contaminants 

will remain in the aquifer after all efforts at restoration and 

will migrate through the aquifer into the future. 

Of even greater concern for us was the paucity of 

information available to Dr. Neupauer and, we assume, to 

the regulators. She noted that a comprehensive modeling 

exercise was impossible because of insufficient data on the 

spatial distribution of various chemical parameters or on 
PAGE 26 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

the chemistry of the injection solution used by the industry. 

After describing several limitations inherent in the study as a 

result of the scant data, Dr. Neupauer noted that “diffusion [of 

chemicals] out of the immobile region can occur over many 

years or decades; thus even if the water in the mobile zone 

appears clean, it may become contaminated over time by 

this diffusive process. This process was not modeled in these 

simulations, but it would further increase the concentration 

of lixiviant in the post-restoration aquifer.”90

As we detail later in this report, Dr. Neupauer’s experience 

is consistent with that of experts at the USGS and elsewhere. 

The ability to accurately assess the long-term environmental 

and public health impacts of ISL mining will depend on 

both a thorough catalog of past aquifer impacts and the 

ability of regulatory agencies to obtain comprehensive and 

publicly transparent data on groundwater quality and the 

geologic properties of the aquifer before the permitting stage. 

Currently, the public documents available to Dr. Neupauer, 

the USGS, and any member of the public are insufficient to 

perform anything more than a limited analysis.

The In-Situ Leach Uranium

Mining Process and Its

Environmental Impacts

As described in Chapter 1, the ISL process involves drilling 

and operating hundreds of injection and production wells 

at each mining site. Mining the aquifer to recover uranium 

in this fashion changes the chemistry of the groundwater, 

increasing concentrations of uranium significantly.91 Levels 

of other naturally occurring radioactive elements and heavy 

metals are increased similarly. These environmental impacts 

are detailed in the pages that follow.

1. In-Situ Leach Mining Alters Groundwater Chemistry

All stages of ISL mining impact surrounding water quality 

because the process invades ore deposits and fundamentally 

alters groundwater chemistry. The NRC itself acknowledges 

these effects in its regulatory guidance, discussed in Chapter 

4.92 While the injected solution—generally a base in U.S. 

mines rather than an acid—may be composed of relatively 

benign chemicals, its leaching results in significantly polluted 

aquifers by oxidizing and freeing heavy metals that were once 

locked and immobile in host rock.

Chemical reactions take place between the solution 

and the host rock at the time of injection. Contaminants 

that escape from the site during injection, as well as 

contaminants that migrate naturally after mining has 

stopped, change water quality.93 The consequences from 

injection alone are serious. Due to the change in the 

aquifer’s ability to produce “reducing” conditions during 

mining, post-mining water quality within the deposit will 

be substantially different from what it was before mining.94

Altering groundwater chemistry has significant short- and 

long-term impacts and merits a searching analysis for the 

reasons discussed in the following sections. 

2. In-Situ Leach Mining Causes Repeated “Spills, Leaks, and 

Excursions” of Contaminants

Aboveground spills and belowground excursions of lixiviant 

can have serious impacts on both surface and groundwater 

quality. These occur with some regularity at ISL operations, 

but more complete information is necessary to understand 

the extent of the environmental harm. Thus far, the NRC 

has failed to conduct a full environmental analysis of ISL 

uranium mining, including a comprehensive review of the 

problem of spills, excursions, and leaks.

While spills can cause environmental harm, they are 

generally aboveground; consequently they can be visually 

monitored and are physically easier to address. Underground 

excursions are more problematic and are of two kinds: 

vertical and horizontal. Vertical excursions occur as lixiviant 

migrates through an improperly sealed well or an incomplete 

confining layer of an aquifer; horizontal (or lateral) 

excursions occur when injection and extraction pumping 

rates are imbalanced and the lixiviant has momentum to 

disperse.95 Monitoring wells set around the injection wells 

can detect the slow leaching of foreign, oxidizing liquid into 

the balanced natural chemistry of the groundwater. Such 

detection serves to identify excursions but triggers only afterthe-fact actions. 

Excursions and leaks have been serious ongoing problems 

for many ISL facilities. In issuing a 2007 Notice of Violation to 

the Cameco Corporation’s Smith Ranch-Highland ISL mine, 

the state of Wyoming noted:

Over the years there have been an 

inordinate number of spills, leaks and 

other releases at this operation. Some 80 

spills have been reported, in addition to 

numerous pond leaks, well casing failures 

and excursions. Unfortunately, it appears 

that such occurrences have become 

routine. The LQD [Land Quality Division] 

currently has two large three-ring binders 

full of spill reports from the Smith RanchHighland operations.96

When commenting on the NRC’s draft GEIS, NRDC 

requested that the NRC provide a list of all excursions 

reported, with the licensee’s explanation of the excursion 

and the regulatory response. This simple but important 

information was not provided in the final GEIS. The 

NRC noted curtly that it had merely written a “historical 

overview” of excursions in Wyoming and Nebraska and 

claimed that any excursions in the Agreement States, such 

as Texas, were outside the scope of the agency’s review.97
PAGE 27 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Whether the information on ISL mine performance came 

from Agreement States or states where the NRC directly 

regulated mining operations was beside the point. If a federal 

agency is performing what is ostensibly a national review 

of the environmental impact of ISL uranium mining, then 

collecting all pertinent data on ISL operations is within the 

comparatively well-financed capacity of the NRC. 

The regulations that purport to govern such matters are 

also lacking. While the NRC has established guidelines (as 

opposed to regulations) for wells that might monitor the 

contaminated aquifers of ISL mines, there are no explicit 

regulatory standards at the federal level for monitoring wells. 

Theoretically, monitoring wells should be placed close enough 

to the well field to ensure quick detection of contamination, 

but far enough away so that false alarms are minimized.98

According to NRC guidance, monitoring wells should be 250 to 

500 feet from the well field and be spaced some 400 feet apart. 

Whether this guidance is adequate is not clear. The multiple 

violations cited by Wyoming at the Smith Ranch-Highland 

ISL mine suggest that it is not. Early detection of excursions 

may depend on a number of factors, including the thickness 

of the aquifer monitored, the distance between the monitor 

wells and the well field and the spacing of monitor wells, 

the frequency of monitor-well sampling, the water-quality 

parameters being sampled, and the concentrations of the 

parameters chosen to signal an excursion.99

As we noted, the original intent of the NRC’s GEIS was to 

“identify and evaluate the potential environmental impacts 

associated with construction, operation, aquifer restoration, 

and decommissioning of in-situ uranium recovery 

facilities.”100 The NRC has neither catalogued nor assessed 

the environmental harm from spills, leaks, and excursions 

at ISL facilities, stating that a more thorough environmental 

review would be forthcoming in site-specific analyses and 

that the “monitoring and reporting requirements” would 

be tailored to individual facilities “on a case-by-case basis.” 

This response provides no meaningful evaluation of the 

environmental impact at existing ISL sites. Given this history, 

the NRC’s pledge to address these “details” on a case-bycase basis at each new mine site, without reference to a 

comprehensive understanding of what has already occurred 

at existing ISL operations, raises doubts as to the NRC’s 

commitment to fulfilling its public health and safety mandate. 

3. In-Situ Leach Mining Uses Scarce Groundwater

ISL mining uses significant amounts of groundwater, both 

during the mining process and throughout the restoration 

period. The NRC’s GEIS document did not offer a detailed 

historical analysis of water use at varying ISL sites; rather, 

it presented a hypothetical scenario for consumptive use 

(that is, the amount of water not returned to the production 

aquifer) based on NRC licensed flow rates for ISL facilities 

that range from about 15,100 to 34,000 liters per minute 

[4,000 to 9,000 gallons per minute].101 The NRC’s assertion is 

that most of this water will be returned to the contaminated 

aquifer during operations. NRC goes on to acknowledge 

that groundwater consumptive use is generally reported to 

be greater during aquifer restoration than during mining 

operations.102 This is true because in the restoration phase 

of “groundwater sweep,” contaminated water is drained 

from the aquifer and not reinjected, so that uncontaminated 

water will be drawn into the aquifer.103 The NRC discussed 

operations at Wyoming’s Irigaray Ranch mine, where 545 

million gallons of water was removed from nine well fields 

where groundwater sweep was performed.104

Concluding that the groundwater consumptive-use 

impact from ISL operations and restoration will be small to 

moderate, the NRC suggests a hypothetical facility in various 

stages of operation and restoration at individual well fields. 

The agency posits that “consumption of 280 million L [74 

million gallons, or 230 acre-feet] in 1 year of restoration 

would be roughly equivalent to the water used to irrigate 

29 hectares [72 acres] in New Mexico for one year. Potential 

environmental impacts are affected by the restoration 

techniques chosen, the severity and extent of contamination, 

and the current and future use of the production and 

surrounding aquifers in the vicinity of the ISL facility or at the 

regional scale.”105

We could find only limited information on the matter. 

As discussed later in this chapter, in light of the fact that 

contamination is significant at every ISL mined aquifer, and 

that restoration has almost always continued far beyond 

what was originally planned, NRDC suggests that the NRC 

refine its analysis, thoroughly compiling the historical record 

of groundwater use at ISL sites to inform any hypothetical 

scenarios. NRDC’s collaborators have noted the same paucity 

of information. In an ongoing ISL licensing proceeding in 

South Dakota, an expert for the Oglala Sioux tribe noted in 

a filing that there was great uncertainty in the ISL mining 

applicant’s estimates of water use, such that it was impossible 

for the regulator, and certainly the public, to meaningfully 

evaluate the environmental impact. Using the industry’s 

own figures from the license application, the expert noted 

a potential range of nearly 600 million gallons to almost 3 

billion gallons over the proposed 17-year life of the project.106

The expert went on to note: 

These inconsistencies [in estimates of water use] 

need to be rectified to enable effective public and 

NRC staff review. Clearly, both of these estimates 

indicate that vast quantities of groundwater will 

be extracted from these aquifers over the long 

term, and it seems overly optimistic to simply 

state that no significant impacts will occur. At 

a minimum, Powertech should be required to 

construct a credible, project water balance and to 

more seriously investigate the potential that such 

large-volume water use might impact local/regional 

groundwater levels. At present, I see no evidence 

that the Application contains a reliable compilation 

of baseline water level data for the surrounding 

domestic and agricultural wells (see discussion 

below). Without such reliable, summarized data, 

there will be no viable method to demonstrate that 

groundwater levels (and related pumping costs) have 

not been impacted by project-related activities.107
PAGE 28 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Throughout the western United States, water scarcity is 

a major concern. Increased groundwater withdrawals in 

the West come with economic, environmental, and social 

consequences, and the population of the West continues 

to increase.108 In many cases, water resources have already 

been overallocated in high-population areas, and many 

communities are unsustainably drawing upon groundwater 

from storage.109

Alpine snowpack and ice bring water and life to the West, 

an area known for drought and low precipitation. The 

melting snowpack of the western mountain ranges delivers 

freshwater to rivers that provide the region with as much 

as 75 percent of its water supply.110 In addition to current 

scarcity problems, climate change threatens to reshape the 

supply and quality of available water. Rising temperatures 

are predicted to reduce alpine snowpack, cause earlier and 

larger peak stream flows, potentially reduce total stream 

flows, create greater evaporation losses, degrade ecosystem 

health, cause sea level rise and more extreme weather 

events, and lead to hotter, drier summers.111 The past 

decade’s most significant international assessment of life in 

a carbon-constrained future pointed out that the evidence 

overwhelmingly indicates that greenhouse warming will alter 

the supply of and demand for water, the quality of water, and 

the health and functioning of aquatic ecosystems.112

An analysis performed in 2010 by the consulting firm Tetra 

Tech for NRDC examined the effects of global warming on 

water supply and demand in the contiguous United States. 

The study found that more than 1,100 counties—one-third 

of all counties in the lower 48 states—will face higher risks 

of water shortages by midcentury as the result of global 

warming, and more than 400 of these counties will face 

extremely high risks of water shortages.113 This analysis 

developed a new Water Supply Sustainability Index based on 

the following criteria: projected water demand, groundwater 

use, susceptibility to drought, projected increase in freshwater 

withdrawals, and projected increase in summer water 

deficit.114 Tetra Tech classified the risk to water sustainability 

for counties meeting two of these criteria as “moderate,” 

counties meeting three criteria were classified as “high,” and 

those meeting four or more were classified as “extreme.” 

Counties meeting less than two criteria were considered by 

Tetra Tech to have low risk to water sustainability.

Table 4 lists the counties with operating, planned, or 

potential ISL sites from the NRDC ISL Mine Database, 

the total number of ISL sites within the county, and the 

calculated risk to water sustainability. A total of 40 ISL sites 

fall within counties for which an extreme risk to water 

sustainability is predicted, and an additional 22 ISL sites fall 

within counties for which a high risk is predicted. Figure 19 

shows point locations for operational, planned, and proposed 

ISL facilities from the NRDC database superimposed on 

the Tetra Tech Water Supply Sustainability Index for 2050, 

including the impacts of climate change. In general, more 

than two-thirds of current or future ISL mining sites fall 

within counties for which moderate or greater risks to water 

sustainability are predicted for 2050, taking into account the 

impacts of climate change.

Facing these complex circumstances, water managers 

have a challenging task ahead of them. Policymakers in each 

state must evaluate their resources and water allocations to 

ensure reliable overall supplies, anticipate future growth, 

and safeguard their economies during times of drought. The 

state of Texas issued a report in 2009 highlighting the cost 

of water scarcity. Among its findings was that “each of the 

several one- or two-year droughts in Texas in the past decade 

has cost agricultural producers and businesses impacted 

by them between $1 billion and $4 billion annually.”115 And 

although roughly 20 million acre-feet of water are permitted 

for consumption annually, the report estimated that in 2010 

there would be only around 13.3 million acre-feet of total 

surface water on hand during times of drought. By 2060 this 

will lead to inadequate water supplies for an estimated 85 

percent of the Texas population.116 The area of south Texas that 

has recently suffered severe drought substantially overlaps the 

state’s existing and likely ISL uranium mining areas. 

Water scarcity issues alone should cause governments and 

communities to rethink whether uranium development and 

other water-intensive natural resource extraction techniques 

(such as coal-bed methane recovery and fracking of shalegas deposits) represent a wise course of action. The tradeoff 

between resource extraction and groundwater protection 

is only one of several complicated issues that face state 

resource professionals. With respect to groundwater scarcity, 

the crucial point is that even if there is a period of significant 

growth in the market for uranium, ISL uranium mining will 

Figure 19: NRDC in-situ leach Mine Database overlaid on a map of 

risk to water sustainability in the year 2050, taking into account the 

impacts of climate change.
PAGE 29 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Table 4: Summary data for in-situ leach sites within counties and the predicted risk to water sustainability from 

the effects of climate change.

Location Number of Operational, Planned, or 

Potential In-Situ Leach Sites

Risk to Water Sustainabiilty in 2050 

With Impacts of Climate Change

Brooks County, Texas 1 Extreme

Campbell County, Wyoming 18 Extreme

Duval County, Texas 6 Extreme

Goliad County, Texas 1 Extreme

Karnes County, Texas 1 Extreme

Kleberg County, Texas 1 Extreme

Live Oak County, Texas 1 Extreme

Sweetwater County, Wyoming 9 Extreme

Webb County, Texas 2 Extreme

Total In-Situ Leach Sites in Counties With Extreme Water Scarcity Predictions for 2050: 40

Converse County, Wyoming 13 High

Dawes County, Nebraska 6 High

Montrose County, Colorado 1 High

Weld County, Colorado 2 High

Total In-Situ Leach Sites in Counties With High Water Scarcity Predictions for 2050: 22

Cibola County, New Mexico 2 Moderate

Fall River County, South Dakota 1 Moderate

Gila County, Arizona 9 Moderate

McKinley County, New Mexico 7 Moderate

Natrona County, Wyoming 1 Moderate

Socorro County, New Mexico 1 Moderate

Weston County, Wyoming 1 Moderate

Total In-Situ Leach Sites in Counties With Moderate Water Scarcity Predictions for 2050: 22

Albany County, Wyoming 2 Low

Carbon County, Wyoming 1 Low

Carter County, Montana 1 Low

Crook County, Wyoming 2 Low

Fremont County, Wyoming 4 Low

Johnson County, Wyoming 6 Low

Total In-Situ Leach Sites in Counties With Low Water Scarcity Predictions for 2050: 16 
PAGE 30 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

constitute only a minor fraction of the uranium resources 

used in the United States, much less the rest of the world. It 

makes no sense to contaminate scarce western groundwater 

and harm iconic western landscapes for uranium production 

that amounts to a small fraction of global uranium output 

and U.S. consumption, and that does not fundamentally 

alter U.S. dependence on foreign sources of uranium. Even 

if a much higher degree of U.S. uranium self-sufficiency 

were, in principle, achievable economically, one would still 

want to weigh the environmental costs, especially the critical 

alternative uses for all the groundwater resources that would 

be impaired by stepped-up ISL mining activity.

4. In-Situ Leach Mining Creates Waste

In addition to using scarce groundwater and altering the 

delicate geochemistry of aquifers, ISL mining is a source of 

waste. The NRC’s GEIS provides one estimate of solid-waste 

volumes from the decommissioning and reclamation of ISL 

mines, and another of the more substantial liquid wastes, 

but the agency decided to forgo the detailed data collection 

and analysis of historical ISL sites that could have provided 

valuable insights.117,118 The EPA, in its 2008 review of uranium 

recovery, stated that it did not have sufficient data to estimate 

the amount of solid and liquid wastes generated by previous 

and currently operating mines.119

The solid waste generated from ISL uranium mining 

is composed largely of soil and bedrock from groundlevel site preparation and construction. Excavating these 

materials exposes them to the wind and rain. Solid waste 

also accumulates from drilling injection and production 

wells and from the radioactive solids that precipitate out of 

leachate solution during processing and storage in holding 

ponds. These wastes are placed into pits and buried during 

reclamation. The solids that accumulate at the bottom of these 

pits can be “slightly” radioactive.120 The leachate solution that 

mine operators inject into the ground to recover uranium also 

recovers some radium. The exact amount is unknown.121

Liquid radioactive waste from ISL mining, a more serious 

matter simply because of its greater volume, is generated 

from well fields, processing plants, and aquifer restoration. 

ISL operators typically collect radioactive sludge in 

evaporation ponds that have liners to prevent leaching into 

the ground, or inject the wastewater into disposal wells deep 

underground. As with solid waste, the EPA reports that only 

limited data are available on the volume of this material. The 

issue merits additional study. 122

For example, a well-known and far-reaching environmental 

consequence of ISL uranium mining is the chemical byproduct selenium, which is liberated from the rock formation 

during ISL mining. One U.S. Fish & Wildlife Service study 

looked directly at the question of wastewater from an ISL 

operation in Wyoming. The report notes that “the effects of 

selenium on fish and aquatic migratory birds have been well 

documented. Selenium concentrations greater than 2 μg/L 

in water are known to impair water bird reproduction and 

survival due to the high potential for dietary toxicity through 

food chain bioaccumulation.”123 Increased amounts of 

selenium in the soil and water have had documented adverse 

effects on wildlife in ISL mining areas.124 The combination of 

wastewater and the tendency for spills to occur—even small 

ones that are quickly contained—can have a cumulative 

negative impact on the environment.125

5. In-Situ Leach Mining Contaminates Aquifers

At the heart of ISL mining’s environmental impact is the 

enduring alteration and degradation of the aquifer in 

which the mining has taken place. Although uranium mine 

operators are required to remediate the contaminated 

water once mining is finished, a complete cleanup of the 

subsurface contamination back to original pre-mining (or 

baseline) conditions has never been accomplished.126 The 

specifics of the legal requirements (or lack thereof) will be 

discussed in some detail in the regulatory section to follow, 

but neither the industry nor the regulators have responded 

effectively to repeated failures to restore groundwater.

The NRC evades responsibility for weak cleanup standards 

at ISL sites by stating that it has not “to date” granted an 

“alternative concentration limit” (ACL) to an operational 

ISL facility.127 The NRC’s response avoids the obvious fact 

Figure 20: Aerial photo of the Highland Ranch project, showing ISL 

well complexes (lower left), a purge storage reservoir (center), and 

a pivot irrigation field (top) where in-situ leach leaching solutions 

are disposed of through irrigation after treatment. The U.S. Fish & 

Wildlife Service has documented the bioaccumulation of radioactive 

selenium in the food chain within in-situ leach pivot irrigation fields. 

Source: Ramirez and Rogers, Selenium in a Wyoming Grassland 

Community Receiving Wastewater From an In Situ Uranium Mine. 
PAGE 31 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

that the agency has ceded authority to several states—Texas, 

Wyoming, Nebraska—and at every other ISL mine we 

could locate, it has allowed more contaminants to be left 

in the aquifer when restoration failed. As will be detailed, 

this occurred even after efforts at restoration substantially 

exceeded initial estimates and license requirements. Call 

the weakened standard an ACL, a variance, or any other 

name. The result is the same: a contaminated aquifer where 

restoration efforts failed. The NRC admits that in its short 

study of 11 restorations at three ISL facilities in Wyoming and 

Nebraska, “data show that over 60 percent of the constituents 

were restored to their preoperational concentrations.”128 Of 

course, this also means that about 40 percent of measured 

constituents were not restored to baseline conditions and 

that concessions to the licensee were made. The NRC’s short 

study and its more extensive GEIS discussed throughout 

this paper have failed to thoroughly investigate the potential 

harms of this incomplete restoration of contaminated 

groundwater. 

The industry’s response to the failure of groundwater 

restoration relies on the blessing of the regulators. One 

license applicant pointed out that “there have been no 

significant, adverse impacts to adjacent, non-exempt USDWs 

[underground sources of drinking water] outside the recovery 

zone and into the related area of review (AOR) from ISL 

operations in the United States [emphasis added].”129 This 

statement is both an acknowledgement and a claim. It is 

a tacit acknowledgement that the mined aquifer—which 

received an SDWA exemption from either the state or the 

EPA—was not restored, and the terms of the license requiring 

restoration to background were not met.The response 

then claims that no drinking water aquifers have suffered 

significant adverse impacts beyond the “recovery zone” (itself 

more extensive than the mined area) within the required 

“area of review.” Note that the statement avoids the question 

of what constitutes “significant” adverse impacts, and further 

qualifies the assurance by limiting it to ISL operations “in the 

United States,” when in reality the largest ISL operations are 

located overseas. 

Fundamentally, we don’t know enough about the extent or 

significance of the adverse impacts of ISL mining on adjacent 

drinking waters, as the NRC’s final GEIS did not undertake 

an analysis. No entity has conducted a thorough regulatory 

assessment to investigate the current state of aquifers in 

proximity to ISL operations. In contrast, we do know that the 

mined aquifers are contaminated. 

Once exempted from the protections of the SDWA, and 

with an NRC (or Agreement State) materials license in 

hand, the ISL industry seems sure to produce aquifers that 

cannot be used as sources of drinking water for generations. 

Considering the existing and impending threats of water 

scarcity and the certainty of contamination, the situation 

warrants a more protective approach that grants aquifer 

exemptions to mining operators only in rare instances. The 

next section of this chapter discusses this in greater detail.

Limited Review of In-Situ Leach Sites

Illustrates That Groundwater Has

Not Been Restored

Despite repeated requests from NRDC and others, the NRC 

has yet to conduct the thorough analysis of ISL groundwater 

restoration and results that we believe is necessary to 

continue licensing new mines.130 NRDC believes it is crucial 

that a detailed cataloguing of ISL restoration history take 

place so that informed decisions can be made regarding 

the efficacy of current techniques and adequacy of relevant 

standards. In public hearings before the NRC commissioners, 

NRDC urged the agency to examine and present to the public 

a history of ISL uranium mining operations that showed 

groundwater conditions before and after mining. 

Furthermore, NRDC believes that the NRC should provide:

(1) A complete listing of all mines where baseline and 

relevant pollution standards— called maximum 

contaminant level (MCL) standards—were not met. 

(2) A complete listing of all mines—regulated either by 

the NRC or by an Agreement State—where alternative 

concentration limits (ACLs), or any otherwise-named 

variance or relaxation of original standards, were used.

(3) Thorough analysis of the post-closure monitoring of all 

ISL mines in all states, including an assessment of the 

current state of contamination and ongoing restoration. 

(4) Thorough analysis of the short- and long-term 

environmental impacts that have resulted from the 

applications of the current regulatory regime, performed 

in conjunction with other federal and state regulators. 

Until NRC addresses this most fundamental issue, it 

cannot properly assess the impact ISL mines have on 

the environment, and without proper assessment of 

such impacts, NRC should not be issuing ISL uranium 

mining licenses. 

Moreover, in light of the historical record of human and 

environmental harm from uranium mining and the agency’s 

statutory charge to protect the public from radiological 

and other nuclear fuel cycle hazards, we urge the NRC to 

work quickly to improve and strengthen what are currently 

inadequate regulations. 

NRDC has neither the resources nor the staff to conduct 

a comprehensive assessment. As explained in Chapter 2, 

NRDC and the Southwest Research and Information Center 

(SRIC) extracted as much public data about the impact of ISL 

mining from NRC and state records as was readily available to 

both organizations. Though not comprehensive, the effort is 

consistent with the limited studies done by other entities. 

In sum, NRDC and SRIC did not find a single ISL operation 

where an aquifer was restored to its pre-mining state for all 

contaminants. Keeping in mind NRC’s assertion that “to date” 

it has not granted an alternative concentration limit to an 

operational ISL facility, we found several examples similar to 

this one for the Benavides and Longoria ISL projects in Texas:

 
PAGE 32 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

“Division of Environmental Programs have 

reviewed the letter dated 5/12/87 from the 

Texas Water Commission (TWC), enclosing 

a request from URI for increasing the 

uranium value in the restoration table for 

the Longoria production area No. 1 aquifer 

to 3.0 mg/l. The earlier uranium value was 

2.0 mg/l (see memo dated 5/4/87), which 

itself was a revision from the baseline value 

of 0.047 mg/l. The new uranium value is 

more realistic in terms of achievability in 

comparison with TWC approved levels for 

other restoration parameters. No federal 

drinking water limits exist for uranium.”131

The NRC may not have granted that particular relaxation 

of the standard, but Texas is an Agreement State and may 

not operate outside of the bounds that NRC regulations 

prescribe.132 The Texas document is not an anomaly, but it 

was difficult to locate data on ISL restoration as it has yet to 

be collected by federal agencies. Combing through the NRC 

website and other public records, however, one can begin to 

construct a picture. 

We found that mines in Nebraska have not been any 

more successful at aquifer restoration than those in Texas. 

Presenting the specific numbers for clarity’s sake, at the Crow 

Butte Uranium Project, the baseline (the pre-mining water 

quality) for uranium was set at 0.092 mg/l. However, in 1999, 

during the stabilization period after restoration ceased (and 

this is one of the relatively few times we found stabilization 

data), concentrations of uranium ranged from 1.09 to 2.33 

mg/l.133 In 2002, the values ranged between 1.6 and 1.8 mg/l. 

Despite a demonstrated failure to restore groundwater quality 

to baseline conditions, NRC accepted the restoration plan.134

The relaxing of standards is not an exception limited 

to a few states. The common practice for the NRC or the 

Agreement State to deem an aquifer “restored” despite 

severely elevated concentrations of uranium, radium-226, 

selenium, and other harmful constituents continued at the 

Smith Ranch–Highland Uranium Project in Wyoming. There, 

the baseline for selenium was originally set at 0.001 mg/l; 

after restoration, the selenium concentration was 0.070 

mg/L. Radium was 675 pCi/L at baseline and 1,153 pCi/L 

after restoration. Uranium was 0.05 mg/l at baseline and 3.53 

mg/l after restoration.135 Power Resources, Inc. failed to come 

anywhere close to meeting baseline conditions, yet the aquifer 

was labeled “restored.”136

At the Irigaray mine, also in Wyoming, the NRC and the 

Wyoming Department of Environmental Quality allowed 

licensee COGEMA to restore groundwater to baseline “class 

of use” when COGEMA failed to restore the actual baseline 

conditions.137 The NRC’s technical report on the restoration 

stated that “when comparing pre-mining baseline ranges to 

post-mining stabilization ranges, several constituents did not 

meet primary restoration targets. When comparing the postmining stabilization means for constituents in production 

units 1 through 9 in round 4 to pre-mining baseline means in 

production units 1 through 9, nearly half of the constituents 

exceed the mean values.”138 At COGEMA’s nearby Christensen 

Ranch project, groundwater concentrations of selenium, 

uranium, and radium-226 (as well as iron, manganese, and 

total dissolved solids) all exceeded target restoration values 

and applicable state or federal standards, even after COGEMA 

claimed to have “completed aquifer restoration.”139

Federal Reviews Are Consistent 

With the Natural Resources Defense

Council’s Conclusion

Our finding that groundwater has not been restored at ISL 

operations is consistent with the NRC’s acknowledgment 

that some 40 percent of measured constituents could not be 

restored to baseline conditions and that concessions were 

made to the licensee on several parameters.140

Our review is also consistent with one done by the USGS. 

In 2008 the agency conducted a study of groundwater 

restoration at ISL mines in Texas, which has a history of not 

requiring restoration of contaminated groundwater to premining conditions.141 Additionally, Texas’s recordkeeping is 

poor. The state’s ISL restoration data are, according to USGS, 

“poorly organized and difficult to search,” and much of the 

information is simply missing.142 Where records were available 

to the USGS, they paint a bleak picture. Of 36 uranium mining 

sites authorized by Texas, 27 were actually developed, resulting 

in the construction of 77 well fields.143 Baseline and amended 

restoration values are available for all 27 developed ISL sites. 

However, “final value” records are available for only 22 of the 

77 well fields (representing just 13 of the 36 mines).144 And of 

those mines for which records were available, “no well field...

returned every element to baseline.”145

A typical example occurred at the Zamzow well field, 

where the baseline for uranium was set at 0.171 mg/L.146

The term baseline is actually a misnomer in that it does not 

refer to what we suspect is the real pre-mining baseline 

concentration of constituents in groundwater over the 

entirety of the aquifer. This suspicion is based on the USGS’s 

reporting. As the USGS describes the process, “restoration 

values are initially set as baseline, with operators selecting 

the highest average concentration from either the production 

or mine area as their restoration goal.”147 We presume this 

means that instead of having to establish a baseline water 

quality for the whole project area and inclusive of a wide 
PAGE 33 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

swath of the affected aquifer, the applicant can select a 

baseline from the immediate production area of the orebearing portion of the aquifer, allowing for an inflated 

standard. And under this standard, the Texas Commission 

on Environmental Quality Underground Injection Control 

program later granted Zamzow an amended limit of 3.00 

mg/L., 17.5 times as high as the pre-mining “baseline” 

value.148 NRDC has no data on the final value achieved 

at Zamzow. 

According to the USGS, Texas is not applying clear 

standards. The USGS states that “there is no clear relationship 

between the final value achieved for uranium in groundwater 

at the [well fields], and the amended restoration goals. 

Amended restoration goals do not reflect the degree of 

restoration achieved at the [well fields] in Texas for which 

final values were available.”149 Nor, we would add, is there 

adequate objective evidence that either the original or 

amended restoration goals are an accurate reflection of the 

area’s pre-mining water quality, or are themselves sufficiently 

protective of present and future groundwater uses.

Private Reviews in Texas Are

Consistent With the Limited Reviews

Conducted by Federal Agencies

Another study on aquifer restoration in Texas, conducted by 

Southwest Groundwater Consulting in 2008, found that ISL 

mining operations were consistently unable to meet original 

restoration standards and routinely granted amended 

standards that were far more lenient.150 The study examined 

the concentration of uranium and radium-226 (as well as 

arsenic and sulfate) at the following Texas mines: Benavides 

1, Benavides 2, Benavides 3, Benavides 4, Brelum 1, Brelum 2, 

Bruni 1, Bruni 6, El Mesquite, Longoria 1, Longoria 2, O’Hern, 

and Rosita.151 In all cases, Texas granted the industry licenseholder amended (and weakened) restoration values for an 

aquifer that remained contaminated. In all but two cases, 

the last sampled concentration of uranium exceeded both 

the original restoration value and the amended restoration 

value.152 In all cases, the last sampled concentration of 

radium-226 exceeded both the original restoration value and 

the amended restoration value.153

In short, with Texas as a prime example, ISL uranium 

mining has no enforceable or meaningful standards 

for establishing pre-mining water quality and ensuring 

groundwater restoration. According to the limited data set 

available for review, the regulator allows licensees to set 

artificially inflated baselines as a target for restoration. The 

regulator then relaxes that standard by routinely allowing the 

licensee to amend its target to a much higher concentration 

level. Licensees then fail, in 100 percent of cases, to meet 

even that relaxed standard for key parameters, again 

foreclosing meaningful future use of the aquifer. 

Detailed Analysis of In-Situ Leach

Uranium Mining’s Environmental

Impacts Is Needed

Countering the suggestions and pressure from public interest 

groups to conduct a searching NEPA analysis, uranium 

and mining industry advocates assert that ISL mining is an 

“environmentally benign” practice.154 NRDC’s review—a 

preliminary effort done in part to fill in the analysis left 

vacant by the NRC’s final GEIS—indicates that ISL mining 

degrades the groundwater systems where the mining 

takes place and does so in a region already suffering from 

environmental harm inflicted by the extraction of oil, gas, 

coal-bed methane, and other resources. As yet, there has 

been no comprehensive review of ISL industry practices or 

assessment of potential options for lessening or remediating 

its environmental harm. Such a detailed, technical review is 

beyond the capacities of a single NGO, but it is hoped that 

this paper can spur the long-overdue interagency assessment 

necessary to ensure that the uranium mining industry does 

not repeat the mistakes of the past.155,156
PAGE 34 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

As Chapters 2 and 3 make clear, the regulatory system for uranium ISL mining is 

inadequate. Industry notes that under the current system, it must obtain multiple 

permits from different regulatory authorities—the NRC, the EPA, state environment 

departments, and state engineers—but on a practical level, the paper burden is not nearly as heavy 

as industry suggests. Examining documents in the ongoing Dewey Burdock ISL application in South 

Dakota, it is apparent that industry submitted many of the same documents to the state or the 

EPA for the operation’s Underground Injection Control application as it did for its NRC materials 

license. More important than the question of the paperwork burden on the industry is whether the 

regulatory scheme is failing to protect human health and the environment and overdue for revision.

iV. The Regulatory Predicament

Regulating Uranium Recovery—

The Division of Authority

The current regulatory system, which manages to be 

complicated and dysfunctional at the same time, presents 

a picture that appears restrictive but fundamentally is not. 

The system needs to be reformed before additional ISL 

mines are licensed.

The Initial Statutory Controls—

1978’s Uranium Mill Tailings

Radiation Control Act 

As discussed earlier in this report, the first imposition 

of any environmental control on conventional uranium 

recovery came with the Uranium Mill Tailings Radiation 

Control Act (UMTRCA). UMTRCA is divided into two titles. 

Title I addresses mill sites that were abandoned by 1978. The 

EPA was directed to promulgate radiation and hazardous 

waste standards for remediation, and DOE was to perform 

the cleanup of abandoned tailings sites (25 former AEA 

sites) subject to NRC licensing.157 Title II focuses on uranium 

milling facilities operating after 1978. It established the 

framework for NRC and Agreement States to regulate mill 

tailings and other wastes at mills licensed by the NRC at the 

time of UMTRCA’s passage, and to adopt the subsequent 

standards set by the EPA.158 To insure the long-term 

stabilization and maintenance of the mill sites and to pass on 

industry’s costs, ownership of the tailings passes to an agency 

of the federal government—such as the DOE—or the state 

after a mill is decommissioned. To date, no state has become 

a perpetual custodian of a uranium mill site. As noted 

above, this law and the subsequent regulations issued by 

the NRC and the EPA have never specifically addressed ISL 

mining operations. 

In-Situ Leach Mining Regulation: NRC

Statutory Authority

Under its AEA authority (Chapters 7 and 8 of the AEA, 

“Source Material” and “Byproduct Material,” respectively), 

the NRC regulates uranium recovery when it involves 

conventional milling (concentration) of uranium ore or 

ISL mining under its regulations for Domestic Licensing 

of Source Material.159 Despite a growing use of the ISL 

technique over the past two decades (and the past few years 

in particular), the NRC has not altered its source material 

licensing regulations to account for the impacts of ISL mining. 
PAGE 35 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Rather than promulgate new rules that would address ISL 

mining, the NRC has used its 10 CFR Part 40 rules (meant 

for mill tailings) and agency guidance and specific license 

conditions to regulate ISL mining in an ad hoc fashion.

In-Situ Leach Mining Regulation: EPA 

Statutory Authority

Under UMTRCA, the EPA has the responsibility to establish 

standards for public exposure to radioactive materials 

originating from mill tailings, and cleanup and control 

standards for inactive uranium tailings sites and operating 

sites. The EPA’s regulations in 40 CFR 192 apply to remediation 

of such properties and address emissions of radon, as well as 

allowable concentrations of radionuclides, metals, and other 

contaminants in surface water and groundwater.160

Despite the ability to do so under 40 CFR 192, the EPA 

has yet to establish radiation protection or other standards 

specific to ISL mining. Fortunately, EPA commenced an effort 

to draft such revised rules in 2009, and we understand the 

agency is now formulating specific groundwater protection 

rules for ISL operations. A draft rule is expected early in 2012. 

Currently, however, since the UMTRCA regulations have 

yet to address ISL mining, the EPA’s chief involvement with 

ISL mining has been through its SDWA authority and its 

Underground Injection Control (UIC) regulations. States can 

be the relevant permitting authority for this matter if the state 

has assumed the EPA’s authority for implementing the SDWA. 

Here, the ISL uranium mining company must apply to the EPA 

or its delegated state for approval of underground injection of 

solutions that will contaminate the exempted aquifer. 

The EPA’s UIC regulations are designed to protect 

underground sources of drinking water (USDWs) by 

prohibiting the direct injection or migration of foreign 

fluids into these aquifers. A USDW is defined as any aquifer 

or portion thereof that supplies a public water system or 

contains fewer than 10,000mg/l total dissolved solids (TDS). 

The EPA stated that “an aquifer may be exempted from UIC 

regulation if it is shown to be completely isolated with no 

possible future uses.”161 The theory is that such an aquifer 

cannot and will not serve as a source of drinking water 

because it is situated at a depth or location that makes 

recovery of the water technically or economically impractical. 

For years the discovery of producible mineral deposits 

led to what amounted to an automatic exemption, even 

in the arid West. That practice, however, is changing as 

calculations of technical and economic impracticability 

evolve over time in light of the increasing scarcity and value 

of groundwater resources. In some states the scrutiny given 

to UIC permits is increasing. For example, South Dakota has 

twice rejected an application submitted by the ISL operator 

Powertech for a UIC permit. The company’s application 

included substantially the same (and in large part identical) 

information as that submitted to the NRC on its ISL license 

application. The state bluntly noted that Powertech’s 

scientific and baseline characterization information “lacks 

sufficient detail to address fundamental questions related to 

whether Powertech can conduct the project in a controlled 

manner to protect groundwater resources.”162

Unfortunately, bowing to industry pressure, the state 

legislature took the unusual step of stripping its own state 

agency, the South Dakota Department of Environment and 

Natural Resources, of the authority to make such regulatory 

decisions.163 South Dakota Governor Dennis Daugaard signed 

this provision into law in March 2011. Now, the authority to 

make such decisions rests with the EPA’s regional office, and 

Powertech has submitted its application.

The Regulatory Scheme for In-Situ

Leach Mines in Action and How They 

Relate to Groundwater

To recap, the unfortunate regulatory scheme works as 

follows. The NRC licenses and regulates ISL operations 

under standards written for conventional uranium mills. By 

statute, the NRC must also adopt EPA standards, also written 

for uranium mills, but then use those standards for ISL 

operations. To present what the industry applicant must do to 

obtain an ISL license, the NRC issues a guidance document.164

The site remediation program (SRP) guidance details how 

the agency will interpret its requirements for groundwater 

restoration under 10 CFR Part 40 (the NRC regulations for 

nuclear “materials” licenses). First, the SRP provides that after 

an ISL mining and milling operation has concluded, the site 

must be cleaned up, or “decommissioned,” and groundwater 

quality must be restored.165 The NRC guidance posits that 

even after receiving an aquifer exemption under the SDWA, 

an ISL uranium mine should restore the contaminated 

groundwater aquifer to NRC-approved background values.166

Such a level of protection for the scarce resource would 

ensure that adjacent groundwater aquifers are safeguarded 

and that other potential future uses of the mined aquifer are 

not compromised. 

The NRC states that if the contaminated groundwater 

cannot be restored to the NRC-approved background 

level, then the aquifer must be restored to the maximum 

concentration levels set in 10 C.F.R. § 40, Appendix A, Table 

5C. And if that standard is not achievable—as the NRC 

notes, “these two options may not be practically achievable 

at a specific site—then the licensee may propose an 

alternate concentration limit that it will argue presents no 

significant hazard.”167

As described previously, in every instance that NRDC 

has been able to locate, the industry has defaulted to 

alternative concentration limits (ACLs) for key parameters 

such as uranium or radium with no agency complaint. 

Agreement States such as Texas have adopted similar rules 

that allow the industry to be relieved of its burden to restore 

contaminated groundwater.168

The combination of an aquifer exemption (making the 

licensee exempt from water quality standards) and a relaxed 

NRC regulatory scheme allowing alternative limits for key 

parameters results in aquifer contamination where the ore 

is mined. If there ever were a need in Wyoming, New Mexico, 

or South Dakota to access the water in the aquifer where 

uranium mining took place for agricultural and possibly even 
PAGE 36 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

drinking water uses, our survey and initial study suggest that 

such an option would be foreclosed. The increasing scarcity 

of water in the American West is a crucial national issue, and 

all sources—be they surface water or groundwater—should 

receive the utmost protection. 

The Need for Rules

Since at least the late 1990s, the commissioners of the NRC 

have shown concern about the “complex and unmanageable” 

regulatory system under which ISL mines operate and 

groundwater restoration is currently managed.169 In 2003 

the NRC sought to delegate regulation of groundwater 

protection to non-Agreement States through memorandums 

of understanding. This approach hit numerous roadblocks 

and was ultimately unsuccessful. In that same year, there 

was also a downturn in the market price of yellowcake, 

which contributed to the commissioners’ decision to defer a 

rulemaking for ISL facilities. 

 In 2006, Commissioner Jeffrey Merrifield called for a 

rulemaking to solve the problems plaguing the regulation and 

protection of groundwater at ISL mining facilities. He stated, 

While the staff has done its best to regulate 

ISL licensees through the generally 

applicable requirements in Part 40 and 

imposition of license conditions, our failure 

to promulgate specific regulations for 

ISLs has resulted in an inconsistent and 

ineffective regulatory program. We have 

been attempting to force a square peg 

into a round hole for years, and I believe 

we should finally remedy this situation 

through notice and comment rulemaking.170

Subsequently the NRC commissioners “directed the NRC 

staff to initiate a rulemaking effort specifically tailored 

to groundwater protection programs in the well-field 

production zone at ISL uranium recovery facilities.”171 In 

2007 the NRC staff met several times with representatives 

of the EPA and the National Mining Association to “reach a 

consensus on a rulemaking strategy.”172

Though it was more than four years ago that the 

NRC commissioners instructed staff to begin work on 

a groundwater protection rule for ISL uranium mining 

facilities, no such rule has been promulgated, despite 

repeated requests from the public for the issuance of a draft 

rule for public comment.173 In March 2010, NRC staff testified 

before the commissioners at a briefing on uranium recovery 

that they “anticipate providing that rule to the Commission 

in draft form in April of this year.”174 In fact, NRC has formed 

a working group, “to revise Appendix A in 10 CFR Part 40 to 

clarify the regulations related to groundwater protection 

at in-situ leach uranium recovery facilities in order to 

improve regulatory efficiency.”175 But still, no changes have 

been made, and the NRC continues to review and grant ISL 

licenses while taking the side of industry on substantive 

issues, as recently evidenced in filings in the Dewey Burdock 

ISL application. 

NRDC has identified two straightforward reasons for the 

current regulatory morass. First, the weak regulatory regime 

exists because ISL uranium mining was not in widespread 

use when conventional uranium mining was first subjected 

to any oversight beyond that of promoting and guaranteeing 

the viability of a market. Laws to protect public health and 

the environment from uranium mining and milling impacts 

were not drafted and passed until several decades of harm 

had already been inflicted across the American West. Those 

laws that were passed have rarely been updated and have 

been haphazardly enforced, with little accountability for lax 

decisions and a decided unwillingness among regulators to 

enforce protective standards. The NRC, the EPA, the DOI, 

the DOE, and the Bureau of Indian Affairs (under its trust 

responsibility) all hold portions of accountability for the 

regulation of past, present, and future harm resulting from 

uranium recovery.

 The second reason for the ongoing failure to address the 

impact of ISL mining is that the existing regulatory schemes 

are assembled from an archaic set of jurisdictional concerns. 

NRC jurisdiction over uranium milling (and eventually ISL 

mining)—and not over conventional uranium mining—is 

founded on the perceived national need for the federal 

government to have full authority over nuclear materials in 

order to ensure the smooth operation of our weapons and 

commercial nuclear industries. The EPA’s authority, granted 

in 1978, has been superimposed on the NRC process, with at 

best grudging acceptance by the nuclear agency. The result is 

a complicated set of standards assembled from regulations 

intended for differing areas. Whether the current situation 

exists by intent or happenstance is almost beside the point. 

The focus must be on curing these archaic deficiencies and 

swiftly developing a more protective regulatory framework 

for uranium recovery of all types, before even more 

environmental damage is done. 

Thankfully, there is progress as, previously noted. EPA 

finally began work on revising the standards that apply to 

uranium recovery (40 CFR 192). When the EPA issues its 

draft standards in early 2012, the NRC, for its part, should 

commence work on its own long-overdue regulatory 

requirements for ISL uranium mining. Such a rulemaking 

can track with EPA’s proposed standards and be finalized 

after EPA concludes its process in 2012. Unless the federal 

government revises the regulatory scheme for ISL uranium 

mining, damage will likely continue as uranium ore will be 

recovered by both conventional and unconventional means 

well into the future. The time to rectify the inadequacies of 

the regulatory structure has long since arrived, and even 

with its scant regulatory history, ISL uranium mining has a 

troubled past that merits specific treatment. 
PAGE 37 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

I

SL uranium mining does not exist in a vacuum. The environmental impacts of uranium 

recovery must be assessed in conjunction with other historical, ongoing, and reasonably 

foreseeable effects of natural resource extraction in the areas of proposed mining. As with 

the many technical issues associated with groundwater restoration detailed in Chapter 2, the NRC’s 

GEIS on ISL uranium recovery provided an opportunity to address the cumulative impact for all 

methods of resource extraction activities. On this crucial issue the NRC failed. 

V. Effects of Multiple Resource

Extraction IN ONE AREA

In its final GEIS, the NRC stated that it does not regulate 

conventional types of mining (uranium or otherwise), 

abandoned mining sites, or any other type of resource 

extraction, but the agency seemingly agreed to address the 

issue of the cumulative impacts of all of these activities 

in subsequent site-specific environmental reviews. 

Unfortunately, when the first site-specific reviews were 

issued, the NRC failed to do a satisfactory job of exploring 

the cumulative impacts of mining in the affected areas. 

The NRC’s effort at analyzing the cumulative impacts of ISL 

operations and other forms of extractive industries in close 

proximity consisted of nothing more than references to 

other environmental impact statements prepared by other 

agencies and unsupported statements that impacts might be 

“moderate” or “not expected to be significant.”

The Nuclear Regulatory Commission’s

Supplemental Environmental Reviews

The first site-specific NEPA reviews performed subsequent 

to the final GEIS dealt with three ISL operations in Wyoming, 

including the proposed Lost Creek mine. There are eight 

ISL facilities and seven conventional uranium mining 

facilities in close proximity to Lost Creek, and an additional 

five proposed ISL and conventional uranium mining 

operations in various stages of the licensing process. Yet the 

Supplemental EIS done for just one of these mines claims 

there will be “no cumulative effect on land use.”176 The NRC 

also states that small impacts to surface water from the Lost 

Creek project will contribute to small to moderate potential 

impacts to the Battle Springs Flat drainage area for past, 

present, and reasonably foreseeable future actions. The 

cumulative groundwater impact is predicted to be moderate. 

These claims were unsupported in the supplemental EIS 

done for the individual mine. NRDC responded to the NRC 

that with potentially 20 mining operations in one area, 

and factoring in construction, transportation, and routine 

operations, it was unclear how the agency reached its 

conclusions regarding “small to moderate” impacts, leaving 

subsequent agency actions open to the charge of being 

arbitrary and capricious.

Another supplemental review performed no better. The 

Moore Ranch ISL operation in Wyoming illustrates why a 

connected and cumulative impact analysis needs to be done. 

There are 17 coal mining operations in the same general 

area, as well as 472 oil and gas production units in the wider 

Powder River Basin and 534 coal-bed methane wells within 

two miles of the boundary of the proposed license area. 

As shown in Figure 23, the Smith Ranch ISL complex has 

more than 100 oil and gas well sites in close proximity. And 

yet again, with no supporting analysis, the NRC states that 

cumulative impacts on land and groundwater are estimated 

to be moderate.177 The NRC’s precise language is that 

impacts are “sufficient to alter noticeably, but not destabilize 

important attributes of the resource considered.”178 As a 

general matter, it is not entirely clear to NRDC what “alter 

noticeably but not destabilize” means. Moreover, the NRC’s 
PAGE 38 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

conclusion, based on no detailed impacts to groundwater, 

surface water, air, soils, wildlife habitat, or other technical 

criteria, leaves the reader and interested public without 

any certain sense the agency has taken a hard look at the 

potential environmental impacts and what alternatives or 

mitigation strategies might be available. 

The Powder River Basin is also home to the proposed 

Nichols Ranch project. The Nichols Ranch area includes 

20 traditional uranium mines—only two of which are 

operational—five ISL mines, and “prolific” coal-bed methane 

production consisting of approximately 44 leases.179 This 

is a substantial density of mining activities. Again the NRC 

anticipates no significant cumulative impacts but provides 

no analytical support for this conclusion. 

It is important to note that coal-bed methane production 

in proximity to ISL mining not only increases the severity 

of drawdown to local groundwater, but also creates a risk 

for cross-contamination. Despite repeated requests from 

NRDC and others, at no point has the NRC analyzed this 

issue. The NRDC’s understanding is that coal-bed methane 

wells are being drilled in close proximity to the proposed 

ISL operations, sometimes in the same geologic formation, 

suggesting at minimum a need for serious and publicly 

transparent agency consultation and analysis. The NRDC 

sees no evidence of this in the documents. 

There is also a risk of leaks and spills from coal-bed 

methane operations that could contaminate upper aquifers. 

In order to produce the methane, large volumes of water 

must first be recovered from the coal deposits. As is well 

documented, coal-bed methane gas operators do not 

have a strong record of environmental safety compliance 

in Wyoming. A press report stated: “In February 2008, the 

federal Bureau of Land Management’s Buffalo field office 

issued a memo to coal-bed methane gas operators stating, 

‘Recently, there have been an extraordinary number of spills 

and undesirable events reported to the Buffalo field office.’”180

Moreover, the Wyoming Department of Environmental 

Quality issued a notice of violation to Williams Production 

RMT Co., the largest coal-bed methane producer in 

Wyoming's Powder River Basin, for spilling 10,000 barrels of 

coal-bed methane waste in western Campbell County. If this 

wastewater was contaminated by concurrent or previous ISL 

operations, the environmental consequences of such a spill 

would be significant.

In short, the NRC chose simply to list other projects in the 

area that “may” have cumulative impacts on the region. The 

NRC does not discuss the contaminants released by coalbed methane operations or even which aquifers and surface 

waters are affected by them. Regional aquifer drawdowns 

are not discussed or analyzed. Nor does the NRC analyze 

how the significantly elevated levels of uranium, radium, or 

other pollutants that result from ISL mining will impact the 

region when combined with contaminants from coal-bed 

methane production. Similarly, there are issues with oil and 

gas exploration that the NRC fails to explore. And no mention 

is made of the fact that groundwater has suffered substantial 

adverse effects as the result of previous uranium mining. 

Figure 21: In-situ leach locations overlaid on a density map of oil and 

gas wells and mines.

Figure 22: In-situ leach locations overlaid on a map of coal-bed 

methane fields and basins.
PAGE 39 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

NRC must provide a thorough accounting of the “time, type, 

place, and scale” of the mining and other disturbances in the 

project areas and, most important, explain the data on which 

it bases its conclusions.

So what should be done? Mining for metals, natural gas, 

and oil is ubiquitous across this region (and has been for 

generations), and the interactive and combined effects 

that this activity is having underground should be 

thoroughly studied. 

As just one example of matters the GEIS could have 

taken up, one of the least studied and understood aspects 

of impacts to groundwater that occur from ISL mining 

is the change in the reducing capacity of the remaining 

water in the system. The reducing or “redox” capacity of 

groundwater substantially impacts water quality because 

of its effect on the mobility of various chemicals. Toxic 

chemicals that seep into the environment as a result of 

oil and gas drilling activities are more mobile when faced 

with elevated contaminant conditions from in-situ mining. 

Oil spills and gas wells can introduce contaminants into 

soils or water. Oil and gas extraction techniques, including 

the hydraulic fracturing that occurs in coal-bed methane 

fields and other formations, can also change the redox 

state of these formations and mobilize naturally occurring 

contaminants. Liquid and solid waste products are often 

dumped into open pits in the ground, and toxic fluids can 

seep into the groundwater when these pits are not properly 

lined. Stormwater can carry these toxic materials to other 

locations.181 Thanks to the carrying and movement capacity 

of groundwater, these extraction activities could interact 

underground. Figures 21, 22, and 23 graphically illustrate 

this point. 

But ultimately, it is the interaction of all the new activities 

that we think merits immediate consideration by all the 

relevant federal agencies. In Wyoming alone, the number of 

oil and gas extraction operations that have come in and out 

of operation since 1900 exceeds 110,000.182 Figure 23: Smith Ranch in-situ leach complex and nearby producing 

or abandoned oil and gas wells.

And while these resource extraction technologies—ISL 

uranium mining, the mining of other minerals, coal-bed 

methane recovery, oil and natural gas extraction, coal strip 

mining—are all happening in and around one another, 

there exists no serious consideration of the cumulative 

environmental impacts. Individual projects do not occur in a 

vacuum, but the federal agencies entrusted with safeguarding 

our precious natural resources treat them as though they do. 
PAGE 40 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

I

SL uranium mining, alone and in concert with other resource extraction activities, 

contaminates groundwater. ISL operations in the United States have repeatedly failed to 

restore aquifers to a pre-mining state, often leaving them unusable for any alternative future 

use. ISL uranium mining is a poor choice to contaminate scarce western groundwater and harm 

iconic western landscapes chasing an increase in domestic uranium production that will provide 

only a small number of short-term jobs and will not fundamentally alter U.S. dependence on 

foreign sources of uranium.

VI. Conclusions and Policy Recommendations

Considering uranium recovery’s poor environmental record, 

the federal government has an obligation to impose a more 

protective regulatory framework on all types of uranium 

recovery before more environmental damage is done. 

Therefore, NRDC recommends a moratorium on any new ISL 

uranium mining licenses until such time as:

(1) the federal government adopts key elements of 

Colorado’s 2008 Land & Water Stewardship Act, which 

requires substantially more stringent protections than 

currently exist in law; 

(2) EPA standards and NRC regulations are updated to reflect 

the best available data on what is required to protect 

the environment from the contamination inflicted by all 

types of uranium recovery; and 

(3) the White House Council on Environmental Quality 

(CEQ) has undertaken a full interagency review of the 

cumulative and connected impacts of all current Federal 

programs and proposed agency actions to facilitate and 

regulate extraction of mineral and fossil-energy resources 

in the arid West, including but not limited to the NRC’s 

program to license new uranium recovery operations.

Congress could, and should, drive the process forward 

vigorously. Clear and quick adoption of key elements of 

Colorado’s Land & Water Stewardship Act of 2008 would 

provide substantial, meaningful protections that do not 

currently exist in law. For example, Congress should require 

any applicant to describe at least five ISL mining operations 

that demonstrate the ability to conduct the proposed mining 

operation without any leakage, migration, or excursion 

outside the permitted area of any leaching solutions or 

groundwater containing minerals, radionuclides, or other 

constituents liberated or introduced by the mine. Congress 

should also require that any applicant provide the detailed 

and transparent data on original water quality that is 

required by the Colorado law.183 If the relevant congressional 

committees are unwilling to take up the matter, then there is 

no reason why the relevant federal agencies could not adopt 

many of these sensible requirements via regulation. 

With respect to updating the existing regulatory regime for 

both conventional and unconventional uranium recovery, 

two agencies and several states figure prominently. The EPA, 

which is required by law to set standards for the protection of 

public health and the environment at uranium and thorium 

milling and ISL mining sites, should press ahead with 

developing more protective regulations. Such regulations 

should include not only outright prohibitions on ISL mining 

in underground sources of drinking water, but also careful 
PAGE 41 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

attention to the complexity of underground aquifers and 

potential drinking water sources. Also, EPA should be clear 

in requiring groundwater restoration that addresses both 

the contaminated ore zone and any adjacent portion of 

the aquifer affected by the ISL mining. Importantly, EPA’s 

restoration standards must be keyed to the overall water 

quality throughout the aquifer, not just an arbitrarily limited 

mining site presented by the applicant. By law, the NRC must 

implement those EPA standards at the uranium mills and ISL 

sites it regulates. As soon as the EPA issues its new standards 

in draft form, the NRC should immediately commence its 

rulemaking to issue long-overdue requirements specific to 

ISL uranium mining. And for their part, states’ adoption 

of improved mining laws would be of enormous benefit.184

Colorado recently enacted a uranium mining law and has 

recently concluded its public process for regulations to 

implement that law.185

Finally, with respect to conducting an appropriate 

environmental review of the purpose, need, alternatives to, 

and cumulative impacts of ISL uranium mining, we have 

concluded that the issue must be analyzed in its totality. The 

CEQ should direct a full interagency review of the cumulative 

and connected environmental impacts of the Federal 

government’s programs and proposed actions to facilitate and 

regulate the extraction of mineral and fossil-energy resources 

in the arid West. This interagency review should address 

the national purposes and needs served by these programs 

and proposed actions; long- and short-term environmental 

impacts on critical natural resources, such as groundwater, 

air quality, animal habitat, and vegetation; and reasonable 

alternatives that might better protect these resources. 

The environmental review effort should include 

participation from the EPA, the NRC, the Department of the 

Interior’s Bureau of Land Management (BLM) and Bureau 

of Indian Affairs (BIA), the U.S. Geological Survey, and the 

Department of Agriculture’s Forest Service. Importantly, 

when the EPA participates in the suggested interagency NEPA 

review, it will quickly become apparent that the EPA must 

also revise its regulations for aquifer exemptions from the 

Safe Drinking Water Act. 

The need for this substantial interagency review was 

made evident by NRC’s multiple failures in carrying out its 

environmental review obligations for ISL uranium mining 

and milling. The NRC should shelve its inadequate final GEIS 

and finally perform, in conjunction with other concerned 

federal agencies, a long-overdue environmental impact 

analysis of western resource extraction technologies that 

affect overlapping and adjacent areas. Such a review should 

analyze the full extent of the cumulative impacts that are by 

default overlooked in environmental analyses of individual 

projects or even programmatic reviews of singular resources, 

such as uranium or natural gas. 

Given the inherent environmental risks of ISL mining, 

pursuit of these recommendations is no guarantee that 

we will avoid a repetition of past mistakes with uranium 

recovery. But 60 years after the original boom cycle, ensuring 

that the domestic uranium recovery industry is meaningfully 

regulated is the bare minimum standard of protection that 

the federal government owes its citizens.

Acknowledgments

The authors would like to extend their thanks to the TAUPO 

Fidelity Fund and the Beatrice R. and Joseph A. Coleman 

Foundation for their generous support for the preparation 

of this report, and to NRDC’s Nuclear Program Director 

Christopher Paine and Senior Analyst Stan Norris for the very 

substantial service they rendered in editing it. We would also 

like to thank former NRDC staff and interns Alyssa Go, Abby 

King, and John Dick, who collected much of the data in the 

report. Consulting hydrogeologist Roseanna Neupauer of the 

University of Colorado provided important technical support 

for the conceptual modeling of groundwater flows at an ISL 

mine but is in no way responsible for the body or conclusions 

of this report, which are entirely our own. 
PAGE 42 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

VII. APPENDIX A: Degradation of Groundwater

Quality from Uranium In-Situ Leach Mining

Degradation of Groundwater Quality from Uranium In-Situ Leach Mining

Roseanna M. Neupauer

May 1, 2009

1 Introduction

Uranium in-situ leach (ISL) mining has been tested or used at several sites throughout the United

States to extract uranium (U) from roll front deposits, and is proposed for use at several more

sites. A roll front deposit forms in the subsurface where uranium minerals that are in the reduced

oxidation state, U(IV), are encountered by oxygenated groundwater. The oxic groundwater oxidizes

the uranium to U(VI), which is soluble in water. Thus, uranium in the form of U(VI) is transported

downgradient with the groundwater until it reaches a zone that is depleted in oxygen. There,

uranium is reduced to U(IV) and precipitates out of solution, forming a roll front deposit.

In ISL mining, an oxygenated acid or alkaline solution (lixiviant) is injected into the subsurface

through one or more wells, is pumped through the ore formation, and is extracted at several

pumping wells. As the solution travels through the ore formation, it oxidizes the mineralized

uranium to its more soluble form, U(VI), which is dissolved in the solution and extracted at the

pumping wells. Uranium is then recovered from the extracted solution. In the U.S., alkaline

lixiviant is used instead because the use of acid lixiviant renders post-mining restoration more

difficult (Taylor et al., 2004). Sulfuric acid lixiviant was tested at two sites (Nine Mile Lake and

Reno Ranch in Wyoming). Due to the presence of calcium carbonate at the site, the acid lixiviant

cause gypsum precipitation on well screens and within the aquifer, reducing the permeability (Mudd,

2001).

During the ISL process, the groundwater chemistry in the vicinity of the ore deposit is altered.

After mining is completed, the groundwater should ideally be restored to its pre-mining conditions.

However, complete restoration is not always possible, so groundwater is often restored to conditions

that satisfy the water quality requirements for the pre-mining class of use.

The typical restoration process at an ISL site follows several stages. In the first stage, called

groundwater sweep, water is pumped out of the extraction wells, but no water is injected into

the injection wells. This step induces the flow of water toward the extraction wells, drawing the

remaining lixiviant out of the aquifer, and sweeping ambient groundwater through the ore zone. In

the second stage, the groundwater treatment stage, pumping is continued, and the pumped water

is treated and reinjected through the injection wells. A reductant can be added to the reinjected

water to enhance chemical reduction of species that were oxidized in the uranium extraction process.

Common forms of treatment are reverse osmosis and ion exchange. A final restoration stage may

include wellfield recirculation where water is produced at the extraction wells and reinjected without

treatment at the injection wells. The purpose of this stage is to homogenize the groundwater within

the ISL zone. In the final stabilization phase, monitoring is continued for approximately six months

to one year to show that the chemical concentrations of various constituents in the groundwater

have stabilized.

The purpose of this document is to report on water quality impacts of uranium in-situ leach

mining based on data from existing ISL sites, focusing on pre-mining characterization and postmining restoration. Water quality effects are mainly due to chemical reactions between the lixiviant

and the host rock, excursions of lixiviant during injection, or natural migration of lixiviant and

1

Roseanna M. Neupauer

May 1, 2009
PAGE 43 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

other mining-affected groundwater after mining has stopped (Davis and Curtis, 2007). This report

addresses the determination of baseline water quality, the establishing of restoration targets, and

potential water quality impacts due to ISL mining.

2 Baseline Water Quality Assessment

The primary goal for restoration of ISL mining sites is to restore the groundwater quality to premining conditions. Thus, establishing the baseline water quality is a critical step for protecting the

quality of the groundwater.

The U.S. Nuclear Regulatory Commission (NRC) has established guidelines for baseline water

quality sampling. To establish baseline water quality, chemical constituents that are expected to increase in concentration due to mining activities should be sampled in the ore zone and surrounding

aquifers (Lusher, 2003). Typical water quality parameters include common constituents (alkalinity,

bicarbonate, calcium, carbonate, chloride, magnesium, nitrate, potassium, sodium, sulfate); trace

and minor elements (arsenic, barium, boron, cadmium, chromium, copper, fluoride, iron, lead,

manganese, mercury, molybdenum, nickel, radium-226, selenium, silver, uranium, vanadium, zinc);

physical indicators (specific conductivity, total dissolved solids (TDS), pH). The spatial and temporal distribution of sample points should be selected to provide enough data to adequately evaluate

natural spatial and temporal variations in constituent concentrations. An acceptable set of samples

should include all perimeter monitoring wells, all upper and lower aquifer monitoring wells, and at

least one well per acre in each well field. For larger sites, less dense sampling is allowable, but the

density must be no less than one well per four acres. Sampling should be conducted at least four

times. For each constituent, the average value and range of values is reported (Lusher, 2003).

In the subsurface, physical and chemical properties can vary substantially over small distances.

In particular, a roll front deposit is characterized by oxidizing conditions upgradient of the roll front

and reducing conditions downgradient of the roll front; however the interface between redox states is

not necessarily at the roll front. A sharp front between ore-bearing and non-ore-bearing sandstone

typically exists at the upgradient side of the roll front deposit; but the uranium concentration on

the downgradient (reduced) side is gradational (Dahlkamp, 2003, Davis and Curtis, 2007). Since

uranium and other metals are highly affected by redox state, the spatial variability in the redox

state within the deposit greatly affects the concentrations of chemical constituents. Therefore,

the baseline water quality may not necessarily be properly characterized by the sparse sample

distribution stated in the NRC guidelines.

For example, At Crow Butte mine in Nebraska, baseline groundwater quality for Mine Unit 1 was

measured for 34 constituents (those listed above, plus sodium, potassium, nitrite, and excluding

silver) from twelve wells scattered approximately uniformly throughout the site. Each well was

assumed to be representative of a circular region with an area of one acre. While the majority

of the site was covered within these one-acre circles, some regions were covered by two or more

one-acre circles; while other regions were not covered by any. For several of the constituents, the

concentrations were relatively uniform throughout the sampled area, varying by a small percentage.

For some constituents, however, the concentrations varied by one half to one order of magnitude

(carbonate, nitrate, arsenic, chromium, lead, molybdenum, vanadium, zinc, uranium, radium-226)

(Crow Butte Resources, Inc., 2000).

The redox condition of groundwater is critical to the mobility of many chemicals. Since roll

front deposits are characterized by sharp changes in redox conditions, an assessment of the pre2
PAGE 44 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

mining redox state, including its spatial variability, seems critical for the complete characterization

of pre-mining conditions.

3 Restoration Goals

The primary target restoration values for each parameter is the arithmetic average of the baseline

water quality samples for that parameter. Of all the restored ISL mining sites that have been

studied for this report, none have met the primary restoration targets. Instead, secondary target

restoration values may be established. These secondary targets are typically based on the class-ofuse standard for the aquifer; however, other methods have been used to establish adjusted target

restoration values.

For example, Title 118 of the Nebraska Department of Environmental Quality (NDEQ) establishes numerical groundwater quality standards for several parameters (NDEQ, 1996). At the Crow

Butte facility, groundwater must be restored to these standards. However, if the sampled baseline

water quality value exceeds these standards, the target restoration value is set at the baseline mean

plus two standard deviations (Crow Butte Resources, Inc., 2000). For parameters that do not have

standards set in Title 118 (e.g., calcium, magnesium), the restoration goal is established according

to the baseline average. For Crow Butte, the restoration goals for calcium, magnesium, potassium,

and sodium were set to ten times the baseline average, to account for the variability in the concentration of these ions as a function of pH (Crow Butte Resources, Inc., 2000). Note, however,

that the post-restoration average values of these constituents were no more than 30% (less than

two standard deviations) above the pre-mining baseline value.

At Bison Basin (Wyoming), target restoration values appear to be set to the highest baseline

value or the drinking water standard (Altair Resources, Inc., 1988).1

In Texas, several ISL mining sites have been under restoration, although very little data are

available. The baseline water quality was established for 26 constituents, and these were set as the

restoration goals. In many cases, however, the restoration goals were amended to higher concentrations, often substantially higher, than baseline values (Southwest Groundwater Consulting, 2008).

No information is available regarding the justification of these amendments.

At Christensen Ranch, Mine Unit 2 (Wyoming), the Mine Unit was divided into MU2 North

and MU2 South, with MU2 North having eight baseline monitoring wells, and MU2 South having

17. Thirty-five water quality parameters were sampled in each well, and the average values were

calculate separately for MU2 North and for MU2 south. These averages were then averaged to obtain the restoration goal for the entire Mine Unit, even though MU2 South had twice as many wells

as MU2 North. After restoration, the primary restoration goals were not met for all constituents, so

secondary restoration goals of Wyoming Department of Environmental Quality standards or EPA

Maximum Contaminant Levels (MCLs) were used (COGEMA, 2008b).

At Smith Ranch Highland Uranium Project (Wyoming), A-Wellfield, secondary restoration

goals were set to Class IV(A) standards, which characterizes the water as suitable for industry.

The class of use was determined based on elevated levels of radium in the baseline water quality

(Janosko, 2004).

Ideally, restoration of ISL mining sites would return the groundwater to its baseline water

1The copy of the report that is available on ADAMS is missing several sections, so a complete analysis was not

possible.

3
PAGE 45 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

quality. As stated above, restoration to this level has not been achieved, so restoration targets

for some constituents are set based on the class of use of the groundwater. Although this results

in sites having lower post-restoration water quality as compared with pre-mining conditions, it is

consistent with other water uses in which water is removed from a water body for its productive

use, and then returned to the same or different water body. In this situation, the water must meet

the water quality standards of the water body to which it is returned, regardless of the quality of

the water that was removed.

4 Potential Water Quality Impacts of ISL Mining

Under natural conditions, a roll front uranium deposit typically has oxidizing conditions upgradient

of the deposit and reducing downgradient of the deposit. During the ISL mining process, an oxidant

is injected into the subsurface via the alkaline lixiviant, thereby changing the geochemistry of the

groundwater. Due to the change in redox conditions during mining, the post-mining water quality

within the deposit will be substantially different than the pre-mining conditions.

The most serious impacts of ISL mining on groundwater quality include the off-site migration

of the lixiviant during production, and the migration of altered groundwater after production has

ceased. To address the first concern, monitoring wells are placed around the production area

and above and below it to monitor for excursions. To address the second concern, groundwater

restoration activities are conducted to return the groundwater to conditions more similar to the

pre-mining state.

Vertical and Horizontal Excursions of the Lixiviant. Perimeter wells are installed around

production zones to detect horizontal excursions of lixiviant migrating out of the production zone,

while monitoring wells are installed in the aquifers above and below the production zone to detect

vertical excursions. If water quality in a monitoring well exceeds pre-specified upper control limits

for selected constituents, measures must be taken to correct the problem. Causes of vertical excursions include vertical migration through improperly sealed wells and incomplete confining layers

(Thompson et al., 2007).

The most common cause of a lateral excursion is an imbalance between injection rates and

extraction rates (Thompson et al., 2007). Corrective action in this case may be a reduction in the

injection rate or an increase in the extraction rate in nearby wells. In the absence of a background

hydraulic gradient, a five-spot pattern with injection wells at the corners injecting at equal rates

Q and a production well in the center extracting water at a rate 4Q, all injected water will be

extracted at the production well. However, if there is a background hydraulic gradient (either the

ambient hydraulic gradient or the gradient induced by production of adjacent patterns or mine

units), some of the injected solution will bypass the production well. An example is shown in

Figure 1a. In the absence of pumping, water flows from left to right with a hydraulic gradient of

0.0017 ft/ft. Four injection wells are located at the locations shown by the circles, injecting at a

rate Q. One extraction well is located at the location shown by the square, and is producing at a

rate 4Q. The travel path of 32 water particles (eight around each injection well) are tracked from

the location marked with a triangle until they reach the extraction well or the domain boundary.

Note that five of the particles bypass the extraction well and exit the right boundary. To reduce the

likelihood of this bypass, the extraction well can be pumped at a higher rate. Figure 1b shows the

effects of production at a rate of 5Q. In this case, most of the water particles reach the extraction

4
PAGE 46 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

7

7.5

8

8.5

x (ft)

y (ft)

a

−200 0 200

−300

−200

−100

0

100

200

300

6

7

7.5

8

8.5

x (ft)

y (ft)

b

−200 0 200

−300

−200

−100

0

100

200

300

Figure 1: Example of water flow paths in a five-spot pattern. (a) extraction rate equal to the sum

of the injection rates. (b) extraction rate exceeding the sum of the injection rates. Circles denote

injection well locations. Square denotes extraction well location. Triangles denote starting point of

water particles. Solid lines denote water particle paths. Number lines denote head contours in ft.

well. This example is for illustrative purposes only. The actual flow paths depends on the injection

and pumping rates, background hydraulic gradient, hydraulic conductivity, heterogeneity, etc.

The NRC has established guidelines for the placement of perimeter monitoring wells, stating

that wells should be placed sufficiently close to the well field to provide timely detection, and

be spaced sufficient close to so that excursions are not likely to be missed. Groundwater flow

direction and velocity should be considered in determining the appropriate position of monitoring

wells (Lusher, 2003).

At Crow Butte Mine Unit 1, the production area covers an area of approximately 1000 ft by 750

ft. Eleven monitoring wells were placed around the perimeter, in an approximately circular pattern

with a radius of approximately 700 ft. The monitoring wells are separated by approximately 400

ft (Crow Butte Resources, Inc., 2000). At Christensen Ranch, each Mine Unit production area

is surrounded by a perimeter monitoring well ring that is approximately 500 ft from the active

production zone, with wells separated by 400 ft to 1000 ft (COGEMA, 2008a).

Hydraulic properties of subsurface materials vary spatially, with water preferentially following

more highly permeable flow paths. The shape of roll front deposits are evidence of differential

flow paths of groundwater. The deposits generally consist of several interconnected rolls that

are formed by differential flow paths through the sandstone that are controlled by thin clay beds

that separate the sandstone into local hydrologic subunits over distances of tens to hundreds of

meters (Dahlkamp, 1993; Davis and Curtis, 2007). These small scale heterogeneities can result

in bifurcating flow paths, possibly producing fast paths through interconnected arrangements of

more highly permeable materials. Although the monitoring well rings are capable of detecting

elevated concentrations in bulk flow, their wide spacing may render them inefficient in detecting

more localized excursions. Note that although small scale heterogeneities can significantly influence

the travel paths of dissolved chemicals, subsurface properties in general cannot be characterized at

these small scales.

A related issue is the placement of the screened interval for the monitoring wells. If the monitoring well is screened over the entire aquifer thickness, the samples collected from the monitoring

well are mixtures of water from the entire aquifer thickness. If concentrations vary vertically, higher

concentration water will be diluted with lower concentration water, and excursions may go unde5
PAGE 47 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

tected, or their detection may be delayed. On the other hand, if monitoring wells are screened only

over a short length, less dilution will occur, but high concentration water may pass above or below

the well screen, again going undetected (Lusher, 2003).

Incomplete Restoration of the Subsurface. As stated above, no aquifers have been restored

to pre-mining conditions; however, some have been restored to secondary restoration goals, while

other exceed the targets for a few constituents. Some examples are provided here.

At Crow Butte, Mine Unit 1, post-mining water quality showed that the average concentrations

of most constituents were 2.5 to 3.5 times higher than the baseline average concentrations. Exceptions included calcium, magnesium, and uranium, with concentrations seven to ten times higher

than baseline; and carbonate and fluoride, with concentrations below baseline. The restoration process included groundwater sweep with pumping at one well, groundwater treatment with reverse

osmosis and ion exchange with reinjected water containing a sodium sulfide reductant, followed by

recirculation. Of the 34 parameters sampled in the baseline water quality analysis, 25 were at or

below their baseline water quality value after restoration. Seven constituents were above baseline

but met the secondary restoration goals (arsenic, radium-226, vanadium, calcium, potassium, magnesium, and uranium). Two constituents (alkalinity and bicarbonate) exceeded the baseline water

quality (by 6% and 9%, respectively), and no permit standards had been established for these

parameters. After restoration, wells were sampled monthly for an additional six months during

the stabilization period. For several of the constituents (alkalinity, ammonium, bicarbonate, calcium, carbonate, chloride, iron, magnesium, manganese, molybdenum, pH, potassium, radium-226,

sodium, conductivity, sulfate, TDS, uranium), the concentrations showed an increasing trend, although concentrations remained below the restoration targets (Crow Butte Resources, Inc., 2000).

Additional sampling conducted three years later showed that concentration of all species, except

iron, either decreased or showed no additional increase. Iron concentrations were expected to decrease eventually as the redox state stabilizes to more reducing conditions (Crow Butte Resources,

Inc., 2002).

Christensen Ranch contains five different mine units (MU) covering approximately 200 acres.

Restoration was conducted using groundwater sweep, followed by groundwater treatment using

reverse osmosis with permeate reinjection, using a hydrogen sulfide reductant in the reinjected

water as necessary. This was followed by recirculation, which was curtailed after it was noticed that

recirculation led to increased levels of oxygen, which would lead to increased mobility of uranium.

Primary target restoration values for 35 parameters were based on baseline means; secondary

restoration goals were set according to Wyoming Department of Environmental Quality (WDEQ)

and U.S. EPA standards. In 2001, the WDEQ classifications were modified so that radium-226

is not considered treatable; thus, all mine units are Class IV due to high uranium concentrations.

For some mine units, the class-of-use had been determined prior to 2001 as Class I (MU2, twelve

wells in MU4, thirteen wells in MU5) or Class III (two wells in MU6) (COGEMA, 2008a,b). After

restoration, 21 to 27 of 35 constituents were at or below the primary restoration values at the five

different mine units; one to three parameters exceeded the primary restoration values but not the

WDEQ Class I or EPA MCL standards; four to six constituents exceeded the primary restoration

values but do not have a WDEQ class I standard or EPA MCL; finally one to six constituents

exceeded both the primary restoration standard and the WDEQ Class I standard or EPA MCL.

These constituents included TDS (MU4), iron (MU2, MU4), manganese (all MUs), selenium (MU4,

MU5, MU6), uranium (MU2, MU4, MU5, MU6), and radium (MU2, MU4) (COGEMA 2008a,b).

6
PAGE 48 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

For the Bison Basin Project, restoration was conducted via groundwater treatment using reverse

osmosis. Water quality data for 31 constituents sampled during the stability period are available

for four wells. The target restoration value, which was often set to the highest baseline value or

the drinking water standard, was exceeded for arsenic (one well), boron, fluoride, iron (two wells),

manganese, and radium (one well) (Altair Resources, Inc., 1988).

At the Smith Ranch Highland Uranium Project A-Wellfield, restoration was conducted using

groundwater sweep, reverse osmosis, and reductant recirculation. The site was determined to be

Class IV(A), suitable for industry use, by the WDEQ. After restoration, 20 of the 35 constituents

were returned to their baseline conditions. Eleven others were returned to Class I standards, one

to Class II standards, and one to Class III standards. Manganese is above the Class II standard,

but no Class III standard exists. The remaining constituent is radium, which is above the average

baseline value (Janosko, 2004).

Potential for Long-Term Groundwater Quality Impact. At some sites, for constituents

whose concentrations remained above restoration goals, additional studies were done to demonstrate

that the potential for long-term degradation of groundwater quality was minimal.

At Smith Ranch Highland Uranium Project A-Wellfield, the post-restoration concentration of

uranium was 675 pCi/L, which is well above the Class I standard of 5 pCi/L. At the monitoring

well ring, concentrations of radium ranged from 3.7 pCi/L to 9.3 pCi/L, indicating that attenuation

of radium occurs downgradient of the ore zone. The conclusion is that although the concentrations

of radium in the ore zone are quite high, they will be diluted by the time the water in the ore zone

reaches the monitoring well ring (Janosko, 2004).

At the Irigaray site in Wyoming, concentrations of some constituents remained above WDEQ

Class I standard after restoration of the wellfield. Groundwater flow and transport modeling was

conducted to assess the long-term impact of these elevated concentrations. The aquifer was assumed to be homogeneous. The transport model simulated the movement of selenium, manganese,

uranium, radium-226, and total dissolved solids. The initial condition was a uniform distribution of

each of these constituents throughout the ore zone, with a concentration based on the measurements

taken during the stabilization phase. No redox reactions were considered. All constituents were

assumed to undergo linear equilibrium sorption, where the concentration in the sorbed phase, Cs, is

linearly proportional to the aqueous phase concentration, C, through the relationship Cs = KdC,

where Kd is the distribution coefficient. The linear equilibrium sorption assumption leads to a

retardation of the solute movement by a factor of R =1+ ρbKd/θ where ρb is the bulk density of

the solid matrix and θ is porosity. Thus, a lower Kd results in high concentrations in the aqueous

phase and faster travel times though the aquifer. A single value of Kd (and therefore R) was used

for each constituent; low values were used to be conservative. Values used for the distribution

coefficient were Kd = 0.1 L/kg for selenium, Kd = 0 for manganese and TDS, Kd = 0.5 L/kg for

uranium, and Kd = 5 L/kg for radium-226. Concentrations were simulated throughout the aquifer

for 300 years, and breakthrough curves were calculated at observation points located 400 ft from

the wellfield. The results show that all constituents will be below the WDEQ Class I standards

when they reach the observation points. For radium-226, the travel time is so low that the radium

from the source zone does not reach the observation points within the 300-year simulation time

frame (Petrotek, 2004).

At the Christensen Ranch site, primary and secondary restoration standards were exceeded

for TDS, iron, manganese, selenium, uranium, and radium. Because of the proximity to Irigaray,

7
PAGE 49 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

the modeling studies at Irigaray were assumed to be consistent with conditions at Christensen

Ranch. It was assumed that the same reduction in concentration between the source zone and

the observation point location 400 ft from the source zone would be seen at Christensen Ranch

as was seen at Irigaray (COGEMA, 2008b). At Mine Unit 2, this reduction would lead to iron

concentrations below the regulatory standards, but uranium and manganese would remain above

the standards. It was assumed that the reducing conditions would limit the mobility of uranium,

while the health risk of manganese would be minimal. Radium was not included in the analysis

(COGEMA 2008a).

The substantial reduction in simulated concentration at the observation points is caused by

dispersion, which is the spreading of the contaminant plume as it moves through the aquifer.

Dispersion is caused by small scale velocity variation, and is treated mathematically in such a

way that the centroid of a contaminant plume travels with the mean groundwater velocity, and the

plume spreads out along the flow direction and in the directions perpendicular to flow. The resulting

simulated solute concentrations are smoothly varying in space. In reality, solute flows preferentially

through more highly permeable zones and will follow a more circuitous path than is described

mathematically. This behavior results in sharper variations in concentration than are predicted with

numerical simulations. The results of a transport simulation represent an “average” distribution

of solute; however, in reality, the some regions will have substantially higher concentrations than

the simulated predictions and other regions will have substantially lower concentrations than the

simulated predictions.

Note that the Irigaray modeling study used a finite difference grid with block of 25 ft × 25 ft ×

21 ft in the ore layer. Thus, the simulated concentration represents the average concentration over

a volume of 13,125 ft3. Given the likelihood of small scale physical and chemical heterogeneities in

the subsurface, solute concentrations can vary substantially over this volume.

In the subsurface, there are likely to be interconnected high permeability zones that cause the

groundwater and solute to travel very quickly through the aquifer. There are also likely to be

extended regions of low permeability that the flow paths tend to avoid, but that the solute may

enter by molecular diffusion. Once inside these zones, the solute remains relatively immobile as

compared with the rest of the aquifer; however, as solute concentrations in the adjacent aquifer

decrease over time, the solute will slowly diffuse out of the immobile zone. The combination of

these two occurrences lead to higher concentrations of solute that arrive at downgradient locations

more quickly than is predicted from a numerical simulation (due to fast paths), and a long, slow

decrease in concentration at a downgradient point as the previously-immobile solute continues to

diffuse out of the immobile zone. Given that groundwater velocities are quite slow (approximately

5 m/yr in the Irigaray model), the duration of the post-restoration stabilization period (6 months

to one year) may not be long enough for groundwater and solute from the production zone to reach

the monitoring well ring. Long-term monitoring may be necessary to ensure that contamination

does not migrate off-site.

The groundwater sweep phase of aquifer restoration draws fresh water into the mined zone and

theoretically displaces the lixiviant. However, some lixiviant may be trapped in the low permeability (immobile) zones, particularly if the mining phase was long relative to the restoration phase,

providing ample time for the lixiviant to diffuse into the lower permeability materials. Since the

lixiviant contains oxidant, as it is released out of the immobile zones back into the now-reducing

aquifer, the redox state of the surrounding water can change, and uranium (and other metals) can

be oxidized into its more mobile state. This would lead to a delayed release of mobile uranium from

8
PAGE 50 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

the ore zone. Again, long-term monitoring may be necessary to ensure that the quality of water is

not compromised.

In the Irigaray modeling study, selenium, uranium, and radium-226 were assumed to follow a

linear equilibrium sorption isotherm. Several studies have found that the distribution coefficient,

Kd, of uranium is dependent upon pH (Echevarria et al., 2001; Davis et al., 2004; Um et al., 2007),

ionic strength (Um et al., 2007), and chemical composition of the water (Davis et al., 2004; Um et

al., 2007). Multiple studies (e.g., Davis et al., 2004; Um et al., 2007) recommended against using

a single value of Kd, noting that it can vary over four orders of magnitude over a range of pH and

carbonate concentrations (Davis et al., 2004).

5 Summary

It has been shown at several ISL sites that post-restoration water quality cannot be returned to

pre-mining conditions; however, secondary restoration standards can often be met, at least for most

constituents. Water quality issues that warrant further attention include:

• The redox state of groundwater substantially impacts the water quality because of its effect

of the mobility of various chemicals. To fully assess the pre-mining baseline water quality,

the post-restoration water quality, and the potential for future water quality degradation, the

redox conditions, including their spatial variability, should be established.

• Subsurface physical and chemical properties vary spatially. Although a complete representation of the spatial variability is not possible, a better characterization of the spatial variability

can be obtained with a more dense sampling network, and if the characterization of spatial

variations is included in the pre-mining baseline water quality and post-restoration assessment.

• Depending on the hydraulic gradient and the pumping and injection rates, some injected

lixiviant may bypass the extraction wells. Pumping at rates that exceed injection is a measure

to reduce the probability of bypass.

• Groundwater travels very slowly and sorbing solutes in the groundwater travel even more

slowly; thus, long-term monitoring may be necessary to protect water quality in the future.

Likewise, solutes that are trapped in immobile regions will be released slowly and may cause

future degradation of water quality. Long-term monitoring can monitor for these solutes as

well.

References

[1] Altair Resources, Inc., Bison Basin Decommissioning Project, Phase I, Final Report, June

1988, ADAMS ML010530105.

[2] COGEMA Mining, Inc., Restoration Data Package, Mine Unit 2, Christensen Ranch Project,

March 5, 2008a, ADAMS ML081060131.

[3] COGEMA Mining, Inc., Wellfield Restoration Report, Christensen Ranch Project, Wyoming,

March 5, 2008b, ADAMS ML081060131.

9
PAGE 51 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

[4] Crow Butte Resources, Inc., Mine Unit 1 Restoration Report Crow Butte Uranium Project,

January 10, 2000, ADAMS ML0033677938.

[5] Crow Butte Resources, Inc., Additional Stability Monitoring Data for Mine Unit 1 Groundwater Restoration, October 11, 2002, ADAMS ML022980095.

[6] Dahlkamp, F.J., Uranium Ore Deposits, Springer-Verlag, New York, 1993.

[7] Davis, J.A. and G.P. Curtis, Consideration of Geochemical Issues in Groundwater Restoration at Uranium In-Situ Leach Mining Facilities, U.S. Nuclear Regulatory Commission,

NUREG/CR-6870, 2007.

[8] Davis, J.A., D.E. Meece, M. Kohler, and G.P. Curtis, Approaches to surface complexation

modeling of Uranium(VI) adsorption on aquifer sediments, Geochimica et Cosmochimica Acta,

68, 3621–3641, 2004.

[9] Echevarria, G., M.I. Sheppard, and J.L. Morel, Effect of pH on the sorption of uranium in

soils, Journal of Environmental Radioactivity, 52, 257–264, 2001.

[10] Janosko, G.S., letter report to W.F. Kearney, Review of Power Resources Inc.’s A-Wellfield

Ground Water Restoration Report for the Smith Ranch-Highland Uranium Project (TAC

LU0032), June 29, 2004, ADAMS ML041840470.

[11] Lusher, J., Standard Review Plan for In Situ Leach Uranium Extraction License Applications,

NUREG-1569, U.S. Nuclear Regulatory Commission, Washington, DC, 2003.

[12] Mudd, G.M., Critical review of acid in situ leach uranium mining, 1, USA and Australia,

Environmental Geology, 41, 390-403, doi:10.1007/s002540100406, 2001.

[13] NDEQ, Title 118 - Ground Water Quality Standards and Use Classification, July 29, 1996,

www.deq.state.ne.us/RuleAndR.nsf/pages/118-Ch-4, accessed April, 2009.

[14] Petrotek Engineering Corporation, Groundwater Flow and Solute Transport Modeling Report,

Irigaray ISL Operation, November 11, 2005, ADAMS ML053270045.

[15] Southwest Groundwater Consulting, Inc., Report on Findings Related to the Restoration of

Groundwater at In-Situ Uranium Mines in South Texas, September 29, 2008.

[16] Taylor, G., V. Farrington, P. Woods, R. Ring, R. Molloy, Review of Environmental Impacts

of the Acid In-situ Leach Uranium Mining Process, CSIRO Land and Water Client Report,

August 2004.

[17] Thompson, A.J., C.S. Pugsley, Tetra Tech Inc., and K. Sweeney, Generic Environmental Report in Support of the Nuclear Regulatory Commission’s Generic Environmental Impact Statement for In Situ Uranium Recovery Facilities, National Mining Association, Washington, DC,

November 30, 2007.

[18] Um, W., R.J. Serne, and K.M. Krupka, Surface complexation modeling of U(VI) sorption to

Hanford sediment with varying geochemical conditions, Environmental Science and Technology, 41, 3587–3592, 2007.

10
PAGE 52 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

VIII. APPENDIX B: Groundwater Flow and Transport Modeling of Uranium ISL Mining

1

Groundwater Flow and Transport Modeling of Uranium ISL Mining

Roseanna M. Neupauer

February 1, 2010

Introduction

Uranium in-situ leach (ISL) mining has been tested or used at several sites throughout the United 

States to extract uranium (U) from roll front deposits, and is proposed for use at several more 

sites. In ISL mining, a lixiviant is injected into the subsurface through one or more wells, is 

pumped through the ore formation, and is extracted at several pumping wells. As the solution 

travels through the ore formation, it oxidizes the mineralized uranium, U(IV), to its more soluble 

form, U(VI), which is dissolved in the solution and extracted at the pumping wells. Uranium is 

then recovered from the extracted solution. The lixiviant is commonly comprised of water with 

added oxygen and carbon dioxide or sodium bicarbonate to mobilize the uranium (EPA, 2007).

During the ISL process, the groundwater chemistry in the vicinity of the ore deposit is altered. 

After mining is completed, the groundwater should ideally be restored to its pre-mining 

conditions. The typical restoration process at an ISL site follows several stages. In the first stage, 

called groundwater sweep, water is pumped out of the extraction wells, but no water is injected 

into the injection wells. This step induces the flow of water toward the extraction wells, drawing 

the remaining lixiviant out of the aquifer, and sweeping ambient groundwater through the ore 

zone. In the second stage, the groundwater treatment stage, pumping is continued, and the

pumped water is treated and reinjected through the injection wells. A reductant can be added to 

the reinjected water to enhance chemical reduction of species that were oxidized in the uranium 

extraction process. Common forms of treatment are reverse osmosis and ion exchange. A final 

restoration stage may include wellfield recirculation where water is produced at the extraction 

wells and reinjected without treatment at the injection wells. The purpose of this stage is to 

homogenize the groundwater within the ISL zone. In the final stabilization phase, monitoring is 

continued for approximately six months to one year to show that the chemical concentrations of 

various constituents in the groundwater have stabilized. Complete restoration has not been 

documented at any ISL mining site. 

The purpose of this report is to document findings of a groundwater modeling study that 

investigated the effects of ISL mining on groundwater quality. Groundwater flow and transport 

simulations were run for an ISL mine using available data from Christensen Ranch, Phase 1, 

Mine Unit 2. The simulations and modeling results are based on available data from the permit 

application (Malapai, 1992) and from a pump test (Hydro, 1993) that was conducted in 

November 1992. This site was chosen for these simulations because of the availability of pump 

test data, which provided spatial data on a finer resolution than what was available in the permit 

application. The pump test was conducted in the southern portion of Mine Unit 2, so it may not 

be representative of the entire Mine Unit. Some of the necessary data were not available, so 

estimates were made using the best available data and the judgment of the modeler. 

Roseanna M. Neupauer

February 1, 2010
PAGE 53 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

2

Physical and Chemical Processes Affecting Chemical Migration

Before mining activities begin, the potential for groundwater contamination in the vicinity of and 

downgradient of the ISL mine can be assessed through groundwater modeling in which the 

movement of dissolved chemicals in the subsurface is simulated. The movement of dissolved 

chemicals depends on physical processes and chemical reactions:

 Physical Processes

o Advection. As groundwater flows through the subsurface, any chemical that is 

dissolved in the groundwater will be transported along with the groundwater. This 

process is called advection. The direction and rate at which the dissolved 

chemicals are advected depends on the direction and rate of groundwater flow and 

on the porosity (ratio of the volume of pores to the total volume) in the subsurface 

material. 

o Dispersion. The subsurface is comprised of solid materials with open pores 

through which water flows. As groundwater flows through the subsurface, it 

cannot follow a straight path because it must flow around the solid grains. In 

addition, on the pore scale, not all water particles travel at the same velocity; 

those traveling near the pore wall travel more slowly than those traveling near the 

center of the pore. This small-scale variation in both magnitude and direction of 

pore-scale velocity leads to spreading of a dissolved chemical, which is called 

dispersion. More spreading takes place in the direction of flow than in the 

direction transverse to flow. On a larger scale, water will preferentially flow 

toward more permeable materials and away from less permeable materials, 

leading to spreading on a larger scale. 

 Chemical Reactions

o Sorption. Some chemicals that are dissolved in water will come out of solution 

and attach to the solid surface of the rock as they travel through the subsurface.

This process is called sorption. The mass of the chemical that sorbs onto a solid 

surface is related to the aqueous concentration of the chemical. As the aqueous 

concentration increases, the sorbed phase mass also increases; and as the aqueous 

concentration decreases, the sorbed phase mass decreases as mass desorbs. The 

end result of the sorption process is that the movement of chemicals may be slow 

relative to the movement of water. 

o Chemical Reactions. Many chemicals near an ISL mine site can react with 

oxygen or other species to be converted into different chemical species. The 

reactions that occur and the rates at which they occur depend on the dissolved 

oxygen concentration (DO), pH, reduction potential (Eh), and other factors. 

To adequately assess the potential for groundwater contamination, all of these processes must be 

simulated in a groundwater model.

Data Needs for Groundwater Flow Simulation

The first step in groundwater modeling is to simulate the flow of groundwater. The rate and 

direction of groundwater movement controls the rate and direction of the movement of dissolved 

chemicals, and it also controls the movement of chemical species and measures (DO, pH, etc.) 
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3

that may react with the chemicals of interest. To adequately simulate the movement of 

groundwater, the following types of information are needed:

 Formation thickness. The subsurface can typically be divided into hydrogeologic units, 

some that transmit water easily (aquifers) and others that do not (aquitards). The 

thickness of a hydrogeologic unit is important in the quantity of water available in the 

unit, the total flow rate or velocity of water through the unit, and the hydraulic connection 

between adjacent units. 

 Ambient hydraulic head distribution and ambient hydraulic gradient. The energy 

state of water is called “hydraulic head” (or just “head”), represents the height above a 

datum that water would rise in an open tube inserted into the aquifer at that point. Water 

flows from high head to low head, so the driving force of groundwater flow is the spatial 

rate of change of head, or the hydraulic gradient. Prior to any pumping at an ISL mining 

site, the magnitude and direction of groundwater flows is controlled by the ambient 

hydraulic gradient, i.e., the change in head determined by natural conditions such as 

surface water bodies that fix the head at discharge points or recharge points, natural 

recharge, and other sources of water. The ambient hydraulic gradient may change with 

time, e.g., as a result of increased recharge in the upstream reaches of the aquifer due to 

snowmelt in the spring and increased recharge due to irrigation of farmland in 

downstream reaches in the summer. In a groundwater flow model, the boundaries of the 

model domain are often represented as specified head boundaries, i.e., the user specifies 

the head at the boundary and the model is used to calculate head at all interior points in 

the domain. In some cases, the model domain boundary is a physical boundary with a 

known hydraulic head, such as a large lake; in other cases, the model domain boundaries 

are arbitrarily set and the values of the hydraulic head at the boundaries are specified by 

interpolating values from head measurements taken from wells that are located inside and 

outside of the domain. 

 Hydraulic conductivity. Hydraulic conductivity is a measure of a material’s ability to 

transmit water. Some materials may transmit water more easily in one direction than in 

another; these materials are called anisotropic. Within a formation, the hydraulic 

conductivity can vary in space, even if the formation is made up of a single material type. 

Hydraulic conductivity can be even more spatially variable if the formation contains 

more than one material type, e.g., sand deposit with fingers of silt. Furthermore, the 

transition from one material type to another may be gradual, leading to a gradual spatial 

variation in hydraulic conductivity. Hydraulic conductivity of different materials can vary 

over several orders of magnitude. Water, and therefore dissolved chemicals in the water, 

will preferentially flow toward materials with higher hydraulic conductivity; thus the 

spatial distribution of hydraulic conductivity is an important factor in controlling both the 

direction and rate of groundwater flow. A related parameter is the transmissivity, which 

is the product of the hydraulic conductivity and the aquifer thickness.

 Storage properties. During injection and extraction of water, the head distribution in the 

aquifer is changed. Depending on the ability of the aquifer material to store and release 

water, which is called the specific storage, the head may quickly reach a new equilibrium 
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4

distribution or it may gradually approach this new equilibrium distribution. The specific 

storage may vary in space. A related parameter is the storage coefficient which is the 

product of the storage coefficient and the aquifer thickness.

 Leakage across aquitards. In general, water flow in aquifers has a strong horizontal 

component and a weak vertical component. The driving force for flow across an aquitard 

is the head difference between the underlying and overlying aquifers, and the flow rate is 

controlled by the thickness of the aquitard and the hydraulic conductivity of the aquitard, 

which is typically much lower than the hydraulic conductivity of the aquifer. Roll front 

deposits are often found in sandstone formations, which have high hydraulic 

conductivity. In an ideal ISL mine site, the sandstone formation is bounded above and 

below by units with very low hydraulic conductivity, preventing any migration of the 

lixiviant or uranium-rich solution into the overlying or underlying aquifers. The injection 

wells will create localized regions of high head and the extraction wells will create 

localized regions of low head; thus the hydraulic gradient between the sandstone unit and 

the overlying and underlying aquifers will be modified during ISL operations. To 

adequately address the potential for leakage of the lixiviant or uranium-rich solution into 

the overlying and underlying aquifers, the hydraulic conductivity and the thicknesses of 

the aquitards must be characterized.

 Injection and extraction wells. During ISL mine operations, lixiviant will be injected 

into multiple wells and uranium-rich solution will be extracted from multiple wells. 

Ideally all of the injected solution will be removed at the extraction wells. Because of the 

ambient gradient, the injected water will be influenced by the hydraulic gradient created 

by the injection and extraction wells and by the ambient hydraulic gradient. During ISL 

mining operation, the dominant influence on flow magnitude and direction in the mine 

area is the injection and pumping due to mining activities; however, the ambient gradient 

still influences the overall direction of flow. If the injection and pumping rates are low 

relative to the ambient groundwater flow, the influence of the ambient gradient will be 

relatively large, but if the injection and pumping rates are high, the influence of the 

ambient gradient will be small. Furthermore, if the ambient hydraulic gradient changes 

with time (as described above), the influence of the ambient gradient may change over 

time. The locations of all wells and the injection and extraction rates are needed to 

adequately determine the flow direction and magnitude during ISL production phase. In 

addition, the screened intervals of the wells may affect the flow field. If the extraction 

wells are not screened through the entire thickness of the formation, some water may 

bypass the wells by traveling above or below the screened interval.

 Duration of the ISL operations. If some lixiviant bypasses an extraction well, it may 

migrate off site. If the injection and extraction wells are operated for a short time, this 

lixiviant will not migrate far from the site and may be re-captured to some degree during 

restoration. If the wells are operated for a long time, the uncaptured lixiviant may 

migrate far beyond the site and may not be re-captured during restoration. The duration 

of the production phase will affect the potential travel distance of uncaptured lixiviant, 

and therefore will affect the size of the area that must be restored.
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5

Survey of Available Geologic and Hydraulic Data at Christensen Ranch

Geologic and hydraulic data were obtained from Christensen Ranch, Phase 1, Mine Unit 2 (see 

Figure 1) in an attempt to simulate the chemical migration resulting from ISL mine operations 

and the ensuing restoration. Data were obtained from the permit application (Malapai, 1992) and 

pumping test records (Hydro, 1993) which are housed at the Wyoming Department of 

Environmental Quality, Land Quality Division. As is evident below, the data available from 

these records were not sufficient to fully characterize the subsurface properties or the ISL mining 

operations. This section describes the available data and assumptions made in parameterizing a 

groundwater flow model for the ISL operations at Mine Unit 2. The permit application presented 

data from several regional monitoring wells. In some cases (e.g., RM-2), the location of the well 

on drawings does not match the coordinates specified in a table. In this report, the coordinates in 

the table were assumed to be correct. The pumping test was conducted in the southern portion of 

Mine Unit 2, and did not include the entire mine unit. In the simulations conducted in this 

report, only the southern portion of Mine Unit 2 was simulated.

 Formation Thickness. The permit application contains a description of the regional 

geology and the site geology, including geophysical logs at several locations throughout 

the Christensen Ranch area. The geophysical logs are taken along transects at intervals 

of approximately 1000 ft. From the geophysical logs, a hydrostratigraphic cross-section 

was created showing three main sandstone units – “J”, “K”, and “L”, from shallowest to 

deepest. A lignite layer underlies the “J” sandstone and a coal layer underlies the “L” 

sandstone. The sandstone units are discontinuous; throughout most of the area, they are 

divided in Upper and Lower subunits separated by aquitards. The “K” sandstone is the 

production unit for the ISL mine. The permit application also contains isopach maps of 

the top and bottom elevations of the “J”, “K”, and “L” units and the interbedded 

aquitards. The maps show elevations at 10’ intervals. Although the cross section shows 

that the sandstone units are divided into two distinct subunits in many areas, the isopach 

maps do not show the vertical boundaries of the subunits. The isopach maps can be used 

to obtain information on aquifer thickness and top and bottom elevation of units for input 

into a groundwater flow model.

 Hydraulic Head. The permit application contains results of sampling at ten regional 

monitoring wells that were sampled throughout Christensen Ranch (see Figure 1). All ten 

wells were sampled in the production zone (Unit K); nine were sampled in the overlying 

Unit J, eight were sampled in the underlying Unit L. One regional well (RM-6) lies 

within the boundaries of Mine Unit 2. The regional hydraulic gradient shows that water 

flows from the southeast to the northwest (see Figure 2).

Prior to the pump test, the head was sampled in several pumping and monitoring wells 

within Mine Unit 2 (see Figure 3). These wells were spaced approximately 200-400 ft 

apart, providing a more accurate representation of the hydraulic gradient around Mine 

Unit 2. Based on the hydraulic gradient determined from these data, the flow direction in 

the production zone is approximately due west, with a gradient of approximately 0.008 

ft/ft (see Figure 4). 
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6

Note that the regional hydraulic gradient does not appear to be representative of the 

hydraulic gradient in Mine Unit 2. The differences can be due to variety of factors such 

as (1) temporally-varying regional hydraulic gradient, or (2) spatial variability in the 

hydraulic gradient that cannot be characterized from the coarse spacing of the regional 

wells.

 Hydraulic Conductivity. The permit application contains results of measurements of 

hydraulic conductivity at the ten regional monitoring wells. Measurements were made 

through falling head permeameter tests and results are shown in Figure 5. At some wells

(RM-2, RM-5, RM-8, and RM-10), measurements were also made using pumping tests. 

The pumping test results are within a factor of two of the permeameter test results. 

Figure 5 shows that the hydraulic conductivity in Christensen Ranch varies spatially over 

about 1.5 orders of magnitude.

Transmissivity was measured during a pumping test at Mine Unit 2. Five different wells 

were pumped during the 84.5-hour pumping test, and drawdown was observed at several 

monitoring wells and pumping wells (when the wells were not pumped). Drawdown data 

were analyzed using the Theis (Theis, 1935) and Cooper-Jacob (Cooper and Jacob, 1946) 

methods to estimate transmissivity and the storage coefficient. For many observation 

wells, drawdown data were not sufficient to estimate aquifer properties using these 

methods (e.g., drawdown was low and was influenced by other fluctuations; or the 

duration of the pumping test was too short). For wells that were analyzed using the Theis 

curve method, hydraulic conductivity values (based on estimated transmissivities and an 

aquifer thickness of 181 ft) are shown in Figure 6. At two pumping wells (2Y32-1 and 

2Z35-1), the estimated hydraulic conductivity is lower than at the monitoring wells (0.11 

ft/d as compared to 0.4 ft/d). This is likely due to the proximity of these wells to the 

pumping well and the short screened interval of these wells. The Theis method assumes 

that flow in the aquifer is approximately horizontal, but near the pumping well the flow is 

likely to have a strong vertical component. These two values are disregarded because 

they may not be representative of the actual aquifer properties.

For comparison, the hydraulic conductivity measured using the falling head permeameter 

test at RM-6 is also shown in Figure 6. This hydraulic conductivity is lower than the 

values estimated from the pumping test. One possible explanation is that the falling head 

permeameter test samples a much smaller volume (many orders of magnitude smaller), so 

this value may not be representative of the aquifer as a whole.

Anisotropy is defined as directional dependence of material property values. In an 

anisotropic aquifer, hydraulic conductivity (or transmissivity) varies with spatial 

orientation. Both the permit application and the pumping test results show the production 

unit to be anisotropic, both horizontally and vertically. The direction of maximum 

horizontal hydraulic conductivity is shown in Figure 5. The direction of the minimum 

horizontal hydraulic conductivity is perpendicular to that. The ratio the maximum to 

minimum horizontal hydraulic conductivities are also shown in Figure 5, along with the 

ratio of horizontal to vertical hydraulic conductivity are shown in Figure 5, where 
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7

available. At RM-6, no anisotropy information was available in the permit application; 

however an anisotropy orientation was available from the pumping test results.

 Storage Coefficient. The permit application shows measured values of the storage 

coefficient at four of the regional monitoring wells (Figure 7). The values differ by about 

a factor of four, and no measurement is provided at RM-6. At Mine Unit 2, the storage 

coefficient was measured during the pumping test for wells that were analyzed using the 

Theis method (Figure 8). These values are within about a factor of three of each other, 

and comparable to the values from the regional monitoring wells.

 Leakage Across Aquitards. The pumping test results show that the overlying and 

underlying aquitards hydraulically isolate the production unit. The pumping rates during 

the pumping test in the production unit were 15.0 gpm at 2Z34-1 for 84.5 hr, 19.2 gpm at 

2AE16-1 and 9.6 gpm at 2X54-1 for the final 55.5 hours, and 12.2 gpm at 2AC24-1 and 

6.7 gpm at 2W50-1 for the final 36.93 hours of the pumping test. At the end of the 

pumping test, the total pumping rate was 62.7 gpm (12,000 ft3

/d). If the ISL mine 

operations put more stress on the aquitards, with higher injection/extraction rates during 

the ISL mining operation or a different distribution of wells throughout the mine site, 

there may be a possibility of leakage across aquitards.

 Injection and Extraction Wells. No specific information was found on the locations of 

the ISL injection and extraction wells at Mine Unit 2. However, some figures in the 

permit application identified a series of points which are likely to be the ISL wells. The 

configuration follows the five-spot pattern in most places, so for the modeling effort, 

wells were assigned as either injection or extraction wells based on the five-spot pattern. 

The well locations and types are shown Figure 9 (Note the change in scale compared with 

other figures of Mine Unit 2). No information was available on the injection or 

extraction rates, so rates were assumed from extraction volumes stated in the permit 

application or the restoration reports. No information was available on the screened 

intervals of the wells, so they were assumed to be screened through the entire thickness of 

Unit K.

 Duration of ISL Operations. No information was found injection/extraction schedule 

for the ISL wells. It was assumed for the purpose of the model that all injection and 

extraction wells were used simultaneously, and their rates remained constant throughout 

the entire operation, which began in March 1993 and ended in May 1997 (COGEMA, 

2008a).

Groundwater Flow Modeling of Christensen Ranch ISL Mine Operations

Groundwater flow was simulation using MODFLOW (McDonald and Harbaugh, 1988), which is 

a modular three-dimensional finite difference groundwater flow simulator. In this cell-centered 

finite difference model, the domain is discretized into rectangular grid blocks, and head is 

calculated in the each of the grid blocks. The graphical user interface, Argus ONE, was used to 

preprocess and post-process the simulation data.
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8

Model Parameterization.

Based on the available data, the best option for parameterizing a groundwater flow model of the 

Mine Unit 2 area is to use the pumping test results and analysis because the data were collected 

at a finer resolution than the regional data. Since the area of interest (Mine Unit 2) is far from 

any natural hydrologic barriers, a model domain is arbitrary. For this model, a rectangular 

domain is used. Since the aquifer has horizontal anisotropy, the domain is aligned in the 

direction of the maximum hydraulic conductivity (i.e., 12o north of east). The model domain is 

shown in Figure 1 and Figure 10. The domain was divided into 50 ft x 50 ft grid blocks for a 

preliminary simulation (described below). For the main simulation, the grid blocks in the region 

of the ISL production wells was further refined to 12.5 ft x 12.5 ft grid blocks, with a band of 25 

ft x 25 ft grid blocks surrounding the fine-grid region. 

An initial model was developed with five geologic units, which were, from top to bottom, Unit J 

sandstone, overlying aquitard, Unit K sandstone (production unit), underlying aquitard, and Unit 

L sandstone. The top and bottom elevations of each of these units were taken from the permit 

application. The permit application contained contour plots of the top and bottom elevations of 

the units. To obtain elevations to be used in the model, the elevations at each of the pumping 

and monitoring wells in Mine Unit 2 were estimated from the contour plots. Using these point 

values, elevations at the center of each grid block were interpolated using Algorithm 624 (Renka, 

1984). After an initial test of the model (based on aquifer properties discussed below), it was 

found that very little leakage occurred across the overlying and underlying aquitards, so only 

Unit K was included in the main simulation. The top elevation and thickness of Unit K are

shown in Figure 11 and Figure 12, respectively.

The boundary conditions for the model domain are defined as prescribed head boundaries along 

the entire perimeter of the domain. Prescribed head boundaries are used because the domain is 

far from any natural hydrologic boundaries. The prescribed head boundaries were obtained by 

interpolated the measured heads in Figure 4 onto the domain boundaries. The heads shown in red 

were not used in the interpolation because they appear to be anomalous. Because the measured 

heads are only on the interior of the domain, the interpolation method does preserve the 

hydraulic gradient throughout the whole domain. In order to preserve the hydraulic gradient, 

pseudopoints were placed outside the eastern and western boundaries of the domain with values 

of head set by imposing the average hydraulic gradient of 0.008 ft/ft in the +x-direction. For 

each pseudopoint, the head was calculated as h = hi + 0.008(x-xi), where hi and xi are the head 

and easting for monitoring well i. A different monitoring well was used for each pseudopoint to 

allow for some natural variability. The pseudopoint locations and heads are shown in Figure 13. 

The map of the heads interpolated from these pseudopoints is shown in Figure 14. The heads in 

the cells along the domain boundary are the boundary conditions for the simulations. 

Hydraulic conductivity was specified for each grid block based on data available from the 

pumping test. The pumping test results showed that Unit K has horizontal anisotropy with the 

maximum value of hydraulic conductivity, Kmax, aligned 12o north of east. The minimum value, 

Kmin, of hydraulic conductivity is in the perpendicular direction, with the ratio Kmax/Kmin=2.63. 

The values shown in Figure 6 were assumed to be the geometric mean values KG of the 

maximum and minimum hydraulic conductivities, i.e., KG

2

=KmaxKmax . With this relationship, 
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9

Kmax=1.62KG. The values for Kmax at each of the sampled points were interpolated onto the grid 

blocks using inverse distance weighting of the five nearest data points. A map of the 

interpolated hydraulic conductivities is shown in Figure 15. These values are the hydraulic 

conductivities along the model rows, i.e., in the direction of the maximum hydraulic 

conductivity. The hydraulic conductivity along the columns was set using the ratio 

Kmax/Kmin=2.63. The ratio of horizontal to vertical hydraulic conductivity was set to 15, which is 

approximately the average of the three ratios shown in Figure 5.

Storage properties were assumed to be uniform throughout Unit K. Specific storage was set to 

10-6 ft-1. Assuming an aquifer thickness of approximately 180 ft, the storage coefficient is 1.8 x 

10-4, which is in the range of the values shown in Figure 8. Porosity was set to 0.26 (COGEMA, 

2008b).

A steady state simulation was run without pumping to obtain a head distribution to use as the 

initial condition in the simulation of the ISL mining operations. For the steady state simulation, 

uniform discretization of 50 ft x 50 ft was used. The resulting head distribution is shown in 

Figure 14. The flow direction is approximately from east to west across the domain, consistent 

with the observations during the pumping test.

Simulations of ISL Mine Operations

The simulations of the ISL mine operations were run as transient simulations, with the initial 

head set to the head distribution shown in Figure 14. At the beginning of the simulation, all 

injection and extraction wells were turned on, and groundwater flow was simulated. The 

locations of the injection and extraction wells are shown in Figure 9. Recall that the exact 

locations, the injection and extraction rates, and whether each well was an injection or extraction 

well were unavailable. All wells were assumed to operate at a constant rate over the entire 

duration of the simulation. The total extraction rate was assumed to by 5% greater than the total 

injection rate. 

In the permit application, a total pumping rate of 2500 gal/min was proposed in the Christensen 

Ranch amendment. The permit included four phases, of which Phase 1 covered approximately 

31% of the total amendment area. Assuming that the total pumping rate for each phase is 

proportional to the amendment area, the total pumping rate for Phase 1 is estimated to be 775 

gal/min. Phase 1 contained three mine units, so it was assumed that the total pumping rate was 

evenly distributed among the three mine units. Although this simulation only covered the 

southern portion of Mine Unit 2, no information is available regarding the location and number 

of wells in the northern portion, so all of the pumping in Mine Unit 2 is assigned to these 

southern wells in this simulation. The assumed well configuration in Figure 9 has 94 injection 

wells and 101 extraction wells. Assuming the same injection rate at each injection well, an 

injection rate of 2.75 gal/min (530 ft3

/d) is used at each injection well. Assuming the total 

extraction rate is 5% higher than the total injection rate, and uniformly dividing the extraction 

over the 101 extraction wells, an extraction rate of 2.69 gal/min (517 ft3/d) is used at each 

extraction well.
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Mine Unit 2 consists of four contiguous wellfield modules – MOD21, MOD22, MOD23, and 

MOD24. Operations began in March 1993 in MOD21, MOD22, and MOD23, and in July 1993 

for MOD24, and continued until May 1997 (COGEMA, 2008a). It is unclear which wells 

belonged to which module, so it is assumed in this study that all wells were operated from March 

1993 to May 1997, a total of four years and two months (50 months).

An initial test simulation was run with these pumping rates, using a uniform 50 ft x 50 ft grid 

block, and five layers (Unit J, overlying aquitard, Unit K, underlying aquitard, and Unit L). The 

purpose of the simulation was to evaluate the hydraulic connection between the production unit 

(Unit K) and the overlying and underlying aquitards (Unit J and Unit L). The simulation results 

showed no visible change in head in Unit L and only a slight change in head in Unit J; therefore, 

the production zone was assumed to be hydraulically isolated from the rest of the subsurface. 

For the remaining simulations, groundwater flow and transport were only simulated in Unit K 

with the finer discretization shown in Figure 10, which will produce more accurate results near 

the wells. Figure 16 shows the head distribution in Unit K over the whole model domain after 50 

months of operations, while Figure 17 shows an enlarged view of the head distribution near the 

ISL mining wells. The head distribution follows the same general trend as the ambient flow 

field, but head is elevated near the injection wells and lowered near the extraction wells. Figure 

18 shows the results of particle tracking simulated using MODPATH (Pollock, 1994). At the 

start of the simulation (which coincides with the start of the ISL mine operations), eight passive 

particles were uniformly placed in the aquifer around each of the injection wells at a radius of 

12.5 ft (the width of one grid block) from the center of the well. The particles were transported 

with the groundwater, and their paths over a 50-month period are shown in Figure 18. Many 

particles are removed at the extraction wells, but many particles remain in the aquifer. 

Simulation of Restoration Operations

The restoration process for Mine Unit 2 is discussed in COGEMA (2008a). There were three 

distinct phases of restoration: groundwater sweep, reverse osmosis, and recirculation:

 Groundwater Sweep. The ISL mining operations were completed in May 1997, and a 

groundwater sweep phase began immediately afterwards at all wellfield modules. This 

phase involves extraction of groundwater with no re-injection for the purpose of 

replacing lixiviant-contaminated groundwater with native groundwater in the mined zone 

(COGEMA, 2008b). This phase lasted until July 1998 (14 months), during which 

60,479,000 gallons of groundwater were extracted (COGEMA, 2008a). For the 

groundwater flow model, it was assumed that all 101 ISL extraction wells were extracting 

water at a continuous and uniform rate during this 14-month period, at a rate of 0.98 

gal/min (188 ft3

/d) at each extraction well. 

 Reverse Osmosis. The reverse osmosis (RO) phase began in October 2000 at MOD211 

and in March and April 2001 at the other three modules and lasted until March 2002, 

with a total extraction of 295,891,000 gallons of water (COGEMA, 2008a). During this 

phase, water is extracted and treated at an above-ground treatment facility using reverse 

osmosis, and treated water is re-injected, with 10-30% over-recovery of water 
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11

(COGEMA, 2008b). For the groundwater flow model, it was assumed that the RO phase 

began in March 2001 at all wellfield modules (since no information was found that 

identified which wells belonged to each module) and ended in March 2002 (12 months 

operation), and use the same ISL injection and extraction wells. Assuming that the 101 

ISL extraction wells were pumped at a continuous and uniform rate over 12 months to 

produce the stated volume of extracted water, each well was pumped at a rate of 5.57 

gal/min (1073 ft3

/d). Assuming 20% over-recovery, only 246,575,800 gallons of water 

were reinjected at the ISL injection wells. Assuming water was reinjected at a continuous 

and uniform rate, the injection rate was 4.99 gal/min (961 ft3

/d) at each well. 

 Recirculation. The recirculation phase began in April 2003 and continued until March 

2004 (11 months), producing 37,091,000 gallons of water (COGEMA, 2008a). For the 

groundwater flow model, it was assumed that injection and extraction occurred at the 

same wells as in the RO phase, with the same ratio of extraction volume to injected 

volume, which is 0.78 gal/min (146 ft3

/d) extracted at each ISL extraction well and 0.68 

gal/min (131 ft3

/d) injected at each ISL injection well. 

Simulation of the restoration operations had five different stress period (i.e., periods in the 

simulation during which pumping rates were constant). Details of these stress periods are shown 

in Table 1.

Prediction

After the restoration simulations, the groundwater flow model was used to simulate groundwater 

movement for an additional 20 years to predict the movement of unrecovered contaminants. The 

same particles that were tracked in Figure 18 were tracked through the restoration operations and 

for an additional 20 years after the restoration operations ended. Their particle tracks are shown 

in Figure 19. The red triangle represents the particle position at the end of the ISL mining 

operations; the green diamond represents the particle position at the end of the groundwater 

sweep phase; the magenta hexagon represent the particle position at the end of the restoration 

phase. For particles that were removed at an extraction well, the line terminates at a well and 

does not necessarily have these markers. For particles that were still in the aquifer 20 years after 

the restoration operations were completed, the particle path line terminates somewhere other than 

at a well. Many particles are removed at the extraction wells during ISL mine operations or 

during the restoration operations; however, many particles remain in the aquifer even 20 years 

after restoration is completed. Note that all of these particles entered the aquifer immediately 

after ISL operations began; therefore they traveled the farthest during the mining operations and 

are least likely to be captured during the restoration operations. For comparison, Figure 20 shows 

the same type of particles tracks for particles that entered midway through the ISL mining 

operations. Here again, some particles remain in the aquifer 20 years after the restoration 

operations are completed, although the number is less than for those that entered at the start of 

the mining operations.
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12

Data Needs for Solute Transport Simulation

 Flow Field. The groundwater flow field determines the groundwater velocity which 

controls the advection mass flux of dissolved chemicals and also affects the rate of 

dispersion. Since the groundwater flow field is obtained from the groundwater flow 

model, all of the data needs of the groundwater flow model affect solute transport.

 Dispersivity. The dispersion process is quantified by three parameters – longitudinal 

dispersivity, horizontal transverse dispersivity, and vertical transverse dispersivity –

which characterize the degree of spreading in the direction of groundwater flow, in the 

horizontal direction transverse to groundwater flow, and in the vertical direction, 

respectively. The degree of spreading is most affected by the degree of heterogeneity of 

hydraulic conductivity of the aquifer. Stochastic theories (e.g., Gelhar, 1993) can be used 

to estimate the dispersivity based on the variability of the hydraulic conductivity, but 

typically, the dispersivity is not measured. A general rule-of-thumb that is often followed 

is that the longitudinal dispersivity is approximately 1/10 of the travel distance of the 

contaminant, with a 10:1 ratio of longitudinal to horizontal transverse dispersivities, and a 

10:1 ratio of horizontal to vertical transverse dispersivities.

 Background Concentrations. A roll front deposit of uranium occurs where uraniumrich oxic groundwater encounters a zone that is depleted in oxygen. There uranium is 

reduced to U(IV) and precipitates out of solution to form the roll front deposit. By the 

nature of the roll front deposit, the geochemistry of the groundwater upgradient of the 

deposit is oxic, while the downgradient groundwater is reduced. Thus, the geochemistry 

at roll-front deposits is complex, with chemical conditions varying substantially in space. 

During ISL mining, lixiviant is injected into a roll front deposit to intentionally change 

the chemistry of the water, oxidizing the U(IV) to U(VI), which is mobile. The change in 

the chemistry of the water affects the solubility of uranium and other metals. Solubility 

depends the reducing potential (Eh) and pH, as well as ionic strength. Ideally, the site 

should be restored to its pre-mining conditions. Since the the geochemistry of the roll 

front deposit is complex, a complete spatial distribution of the concentration of metals, 

dissolved oxygen, pH, Eh, etc., is needed to make accurate predictions of the chemistry 

of the groundwater during mining operations, during restoration operations, and to assess 

the degree of restoration.

 Chemical Reaction Rates. To accurately predict the fate and transport of uranium and 

other metals, sorption parameters and reaction rates and pathways must be quantified. 

Several studies have found that the sorption of uranium is dependent upon pH 

(Echevarria et al., 2001; Davis et al., 2004; Um et al., 2007), ionic strength (Um et al., 

2007), and chemical composition of the water (Davis et al., 2004; Um et al., 2007). The 

partition coefficient for sorption of uranium can vary over four orders of magnitude over 

a range of pH and carbonate concentrations (Davis et al., 2004). Thus, the accurate 

prediction of the reactions relies on an accurate and complete assessment of the 

groundwater chemistry.
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13

 Lixiviant Chemistry. The chemicals in the lixiviant and their concentrations affect the 

chemistry of the groundwater and therefore the chemical reactions that occur during and 

after the ISL mining operations.

Survey of Available Geochemical Data at Christensen Ranch

 Flow Field. The data available for accurate simulation of the flow field at Christensen 

Ranch is discussed above.

 Dispersivity. Dispersivity is typically not measured in the field, and no dispersivity data 

are available for this location. 

 Background Concentrations. The permit application contains water quality data 

conducted for a baseline water quality assessment. For each of the regional monitoring 

wells, samples were taken quarterly in Units J, K, and L. Chemical constituents that were 

sampled include pH, major ions (Ca, Mg, Na, K, CO3, CO3-total, HCO3, SO4, Cl, NH4, 

NH3, NO2, NO3, F, SiO2, TDS, conductivity, alkalinity, hardness, sodium adsorption 

ratio, residual sodium carbonate), trace metals (Al, As, Ba, B, Cd, Co, Cr, Cu, Fe, Pb, 

Mn, Hg, Mo, Ni, Se, V, Zn), and radiometric (U, 226Ra, 230Th, 210Po, 210Pb, gross alpha). 

Measurements at a single location in a mine unit are not sufficient to characterize the 

highly variable groundwater chemistry at a roll front deposit. More dense sampling was 

conducted at specific sites. For example, the permit application includes baseline water 

quality data from the Willow Creek R&D site (located in the southern region of Phase 1). 

Results are compiled into mean values for wellfield wells, monitoring wells, shallow 

wells (Unit J), and deep wells (Unit K); however, only the mean value, and maximum 

and minimum values are reported. The spatial distribution of the chemical parameters 

was not found in the available information.

 Chemical Reaction Rates. No data were found regarding chemical reaction rates.

 Lixiviant Chemistry. According to the COGEMA (2008a), the lixiviant contained 

sodium bicarbonate and gaseous oxygen. No information was available on the 

concentration of these chemicals in the lixiviant.

Solute Transport Modeling of Christensen Ranch ISL Mine Operations

Because of the lack of spatial data on the pre-mining chemistry and the concentration data for the 

lixiviant, an accurate simulation of change in groundwater chemistry during and after the mining 

operations could not be conducted. Instead, a simulation is conducted to model the transport of 

lixiviant in the absence of any chemical reactions. During the simulation of ISL mining 

operations, the lixiviant is injected into the injection wells. The injected solution is assumed to 

contain 100% lixiviant (which is comprised of water, sodium bicarbonate, oxygen, and likely 

low concentrations of other chemicals). As the lixiviant is introduced to the aquifer, it displaces 

native groundwater, forming an interface between lixiviant and the native groundwater. At this 

interface, the native groundwater and lixiviant mix. Behind the interface, the water is nearly 

100% lixiviant; ahead of the interface, the water is nearly 100% native groundwater; and along 
PAGE 65 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

14

the interface, the water is a mixture of native groundwater and lixiviant. The transport 

simulations in this report model the movement of this interface and the width of the mixed zone.

Transport Model Parameterization.

The flow field for the transport model was developed by the groundwater flow simulation. The 

only additional parameter needed to obtain the groundwater velocity from the flow simulation 

results is the porosity, which was taken as a uniform value of 0.26 (COGEMA 2008b). 

Dispersivity values were set to 10 ft for the longitudinal dispersivity and 1 ft for the horizontal 

transverse dispersivity. Note that with the assumption of fully-penetrating wells in Unit K, the 

lixiviant is assumed to be distributed uniformly over the thickness of Unit K, so vertical 

spreading does not occur. 

Transport Simulations of ISL Mine Operations

To simulate the injection of lixiviant, a “concentration” of 100 (representing 100% lixiviant) is 

assigned to the water that is injected during the ISL mine operations. This “concentration” is 

injected at a constant rate over the entire stress period that simulation ISL mine operations. The 

results can be interpreted as the percentage of lixiviant in the groundwater. Where the 

percentage is high, a substantial change in groundwater chemistry is likely; where the percentage 

is low, the change in groundwater chemistry may not be significant. Lixiviant is either extracted 

at the extraction wells or it remains in the aquifer. MT3DMS (Zheng and Wang, 1999) was used 

to simulate the transport of lixiviant. The results are shown in Figure 21. The white/blue 

interface represents 1% of lixiviant in the solution, so this is essentially the interface between 

native groundwater and contaminated groundwater. The percentage of lixiviant in the water is 

high near the ISL wells; the contaminated zone extends slightly beyond the perimeter of the 

wellfield. 

Transport Simulation of Restoration Operations

No lixiviant is introduced during restoration operations. During the groundwater sweep phase, 

lixiviant-containing groundwater is removed at extraction wells and is replaced by native 

groundwater that flows toward the wells. Thus this simulation models the movement of interface 

between lixiviant and native groundwater, as it gets drawn back toward the wells. In the RO 

phase, clean water is injected at the ISL injection wells, further driving the position of the 

interface toward the ISL extraction wells. Figure 22 shows the percentage of lixiviant in 

groundwater at the end of the restoration operations. The percentages are substantially reduced

during the restoration period; however, an appreciable amount of lixiviant still remains in the 

aquifer. 

Prediction of Solute Concentrations

After restoration operations are completed, any lixiviant remaining in the aquifer will be 

transported by the ambient groundwater flow. The final phase of the solute transport simulation 

models this movement. Figure 23 shows the percentage of lixiviant is the groundwater 20 years 

after restoration operations are completed. The plume travels downstream (west) relative to its 
PAGE 66 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

15

position at the end of the restoration phase. The amount of lixiviant is unchanged from Figure 

22; however, the magnitudes are reduced due to dispersion. Although the restoration operations 

are designed to remove the lixiviant, some lixiviant remains in the aquifer. This is likely a result 

of two challenges. First, the ambient hydraulic gradient drives flow to the west. The restoration 

must draw the injected water back toward the extraction wells, and it must also overcome the 

ambient gradient. Secondly, the flow paths are different between the production and restoration 

phases; therefore the restoration does not simply “undo” the spread of lixiviant that occurred 

during production. Because of dispersion, lixiviant is spread through the aquifer during the 

production phase, and is continues to spread due to dispersion, but in different directions, in the 

restoration phase. In addition, there are two inactive periods – one after the groundwater sweep 

phase and one after the RO phase. During this time, the movement of the lixiviant is controlled 

by the ambient hydraulic gradient; thus the lixiviant is transported to the west and some lixiviant 

may bypass the extraction wells. For these reasons, the complete removal of lixiviant is unlikely. 

This situation is more pronounced for a high ambient hydraulic gradient relative to the gradient 

caused by pumping. Recall that only the southern portion of Mine Unit 2 is modeled here, but all 

of the pumping for all of Mine Unit 2 has been apportioned to these wells. With this assumption, 

the simulated hydraulic gradient caused by pumping is likely to be larger than the actual 

hydraulic gradient caused by pumping; therefore the observed impact of the ambient hydraulic 

gradient in these simulation results is conservative. The actual effect might be more pronounced 

with lower pumping rates. 

Alternative Groundwater Flow Model

The purpose of this section is to demonstrate the importance of accurate data in setting up a 

groundwater flow simulation. If only the data from the permit application were used to 

parameterize the groundwater flow model, a different scenario would be modeled. The top and 

bottom elevations of Unit K and the storage properties do not change. The differences are 

highlighted here.

 Prescribed Hydraulic Gradient. The permit application data show a hydraulic gradient 

aligned approximately 45o S of E (Figure 2) with a magnitude of 0.009 ft/ft.

 Hydraulic Conductivity. Based on the permit application, no information is available 

regarding the anisotropy at Mine Unit 2 (from sampling at RM-6), so Mine Unit 2 is 

assumed to be isotropic. Since only one hydraulic conductivity measurement from the 

regional monitoring wells is available near Mine Unit 2, the hydraulic conductivity is 

assumed to be homogeneous with a value of 0.077 ft/d (see Figure 5). 

 Grid. For isotropic aquifers, the model domain should be aligned with the flow 

direction, so the grid is aligned at approximately 45o N of W. The discretization is 

approximately 50 ft x 50 ft on the outer edges and is reduced to 13 ft x 13 ft in the 

interior of the domain. (See Figure 24).

 Boundary Conditions. The boundary conditions are still prescribed head boundaries, but 

they are based on the single head measurement from the regional monitoring well in the 

Mine Unit 2 area, and the specified hydraulic gradient. 
PAGE 67 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

16

The alternative groundwater flow model was used to simulate groundwater movement during 

mining operations, restoration operations, and for an additional 20 years after the completion of 

restoration to predict the movement of unrecovered contaminants. Particle tracks for particles 

introduced around each injection well at the start of mining operations are shown in Figure 25. 

In comparison to the particles in Figure 19, fewer particles remain in the aquifer 20 years after 

restoration was completed for this simulation; however, not all particles were removed during 

restoration. 

The alternative model was used to simulate lixiviant movement. The results are shown in Figures 

26 – 28 at the end of production, at the end of restoration, and at 20 years after the end of 

restoration, respectively. Again in this simulation, a sizeable amount of lixiviant remains in the 

aquifer after restoration and 20 years after the completion of restoration operations, although the 

concentrations are lower than in the previous simulation.

Discussion and Conclusions

Simulations of groundwater flow and contaminant transport were conducted for a region of 

Christensen Ranch, Wyoming. The simulations were based on data available from the permit 

application and from pump test data; however, there were limitations in the available data. The 

simulations modeled the injection of lixiviant and extraction of uranium-rich solution during ISL 

mining operations, restoration operations including groundwater sweep, reverse osmosis, and 

recirculation, and prediction of the groundwater and solute movement for an additional 20 years 

after completion of restoration. The results show that some lixiviant will remain in the aquifer 

after restoration, and this lixiviant will continue to migrate through the aquifer into the future. 

A complete simulation of the chemical evolution of the contaminated region was not possible 

because there was insufficient data on the spatial distribution of various chemical parameters or 

on the chemistry of the lixiviant.

The simulations in this report did not include many complexities that could exist. For example, 

subsurface rocks often are characterized by mobile and immobile regions on the pore scale. 

Water flows through the interconnected pores that make up the mobile region; thus dissolved 

chemicals pass through the mobile region due to both advection and dispersion. The immobile 

region is made up of isolated pores that are not interconnected; dissolved chemicals can only 

enter or exit the immobile region through molecular diffusion which is a slow process. 

Chemicals can diffuse into the immobile region when concentrations in the adjacent mobile 

region are high, but once the concentration in the mobile region drops, chemicals diffuse slowly 

out of the immobile region. The diffusion out of the immobile region can occur over many years 

or decades; thus even if the water in the mobile zone appears clean, it may become contaminated 

over time by this diffusive process. This process was not modeled in these simulations, but it 

would further increase the concentration of lixiviant in the post-restoration aquifer.
PAGE 68 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

17

References

COGEMA Mining, Inc., Restoration Data Package, Mine Unit 2, Christensen Ranch Project,

March 5, 2008a, ADAMS ML081060131.

COGEMA Mining, Inc., Wellfield Restoration Report, Christensen Ranch Project, Wyoming,

March 5, 2008b, ADAMS ML081060131.

Cooper, H.H. and C.E. Jacob, A generalized graphical method for evaluating formation constants

and summarizing well field history, Transactions, American Geophysical Union, 27, 526, 

1946.

Davis, J.A., D.E. Meece, M. Kohler, and G.P. Curtis, Approaches to surface complexation

modeling of Uranium(VI) adsorption on aquifer sediments, Geochimica et Cosmochimica 

Acta, 68, 3621–3641, 2004.

Echevarria, G., M.I. Sheppard, and J.L. Morel, Effect of pH on the sorption of uranium in soils, 

Journal of Environmental Radioactivity, 52, 257–264, 2001.

U.S. Environmental Protection Agency (EPA), Technical Report on Technologically Enhanced 

Naturally Occurring Radioactive Materials from Uranium Mining, Volume 1: Mining 

and Reclamation Background, U.S. Environmental Protection Agency, Office of 

Radiation and Indoor Air, Radiation Protection Division (6608J), Washington, DC, EPA 

402-R-08-005, 2007.

Gelhar, L.W., Stochastic Subsurface Hydrology, Prentice Hall, Englewood Cliffs, New Jersey, 

1993.

Hydro Restoration Corporation, Pump Test Analysis Mine Unit 2 – Southern Portion, 

Christensen Ranch Project, Johnson County, Wyoming, November 1992, January 1993.

Malapai Resources Company, Christensen Ranch Amendment Application to WDEQ to Mine 

No. 478 and NRC License SUA-1341, 1988.

McDonald, M.G. and A.W. Harbaugh, Modular three-dimensional finite-difference groundwater 

flow model. Techniques of water-resources investigations of U.S. Geological Survey, 

Book 6, Chapter A-1, 1988.

Pollock, D.W., 1994, User's Guide for MODPATH/MODPATH-PLOT, Version 3: A particle 

tracking post-processing package for MODFLOW, the U.S. Geological Survey finitedifference ground-water flow model: U.S. Geological Survey Open-File Report 94-464, 6 

ch.

Renka, R.J. Algorithm 624: Triangulation and interpolation at arbitrarily distribution points in 

the plane, ACM Transactions on Mathematical Software, 10(4), 440-442, 1984.

Theis, C.V., The relation between the lowering of the piezometric surface and the rate and 

duration of discharge of a well using ground-water storage, Transactions, American 

Geophysical Union, 16, 519, 1935.

Um, W., R.J. Serne, and K.M. Krupka, Surface complexation modeling of U(VI) sorption to

Hanford sediment with varying geochemical conditions, Environmental Science and 

Technology, 41, 3587–3592, 2007.

Zheng, C. and P.P. Wang, MT3DMS: Documentation and User’s Guide, U.S. Army Corps of 

Engineers, Washington, DC, November 1999.
PAGE 69 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

18

Table 1. Stress periods in the groundwater flow simulation.

Stress 

Period Phase

Start 

Date

End 

Date

Duration 

(days)

Injection rate1

ISL injection wells

gal/min (ft3/d)

ISL extraction wells

gal/min (ft3/d)

1 ISL Operation 3/1993 5/1997 1520 2.75 (530) -2.69 (-517)

2 Groundwater 

Sweep

5/1997 7/1998 425 0 (0) -0.98 (-188)

3 Inactive 

Period

7/1998 3/2001 975 0 (0) 0 (0)

4 RO 3/2001 3/2002 365 4.99 (961) -5.57 (-1073)

5 Inactive 

Period

3/2002 4/2003 395 0 (0) 0 (0)

6 Recirculation 4/2003 3/2004 335 0.68 (131) -0.76 (146)

7 Prediction 3/2004 3/2024 7300 0 (0) 0 (0)

1 Positive value indicated injection; negative value indicates extraction.
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Figure 1. Location of the ten regional monitoring wells (circles) within the Christensen Ranch 

boundary (approximate). Dashed line represents the approximate boundary of Phase 1. Dotdash line represents the inset for Mine Unit 2. Dotted line represents the model domain 

boundary.
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Figure 2. Measured head (in ft) at ten regional monitoring wells (circles) with interpolated 

equipotential lines. The groundwater flow direction is approximately perpendicular to the 

equipotential lines, i.e., from the southeast to the northwest. The head measurement at RM-3 

(shown in red) is much lower than the measurements in neighboring wells, so it was not included 

in the interpolation. 
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Figure 3. Location of the pumping and monitoring wells at Mine Unit 2 (circles). The square 

denotes the one regional sampling well (RM-6) within Mine Unit 2
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Figure 4. Measured head (in ft) at Mine Unit 2 with interpolated equipotential lines. The 

groundwater flow direction is approximately perpendicular to the equipotential lines, i.e., from 

the east to the west. The head measurement at RM-6, MW28, and MW85 (shown in red) are 

much different than the measurements in neighboring wells, so they were not included in the 

interpolation. 
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Figure 5. Regional monitoring well locations (circles). Values to the right of the circles are 

hydraulic conductivity values (in ft/d) measured with falling head permeameter tests. Values to 

left of the circles are direction of the maximum horizontal hydraulic conductivity, with 0o due 

east, and values increasing in the counterclockwise direction. Values above the circles are the 

ratio of maximum to minimum horizontal hydraulic conductivities. Values below the circles are 

the ratio of horizontal to vertical hydraulic conductivity. All values are obtained from the permit 

application, except the direction of the maximum horizontal hydraulic conductivity at RM-6 and 

the ratio of maximum to minimum horizontal hydraulic conductivities at RM-6 (shown in red), 

which were obtained from the pumping test analysis.
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Figure 6. Hydraulic conductivity values (in ft/d) from pumping test at Mine Unit 2. Circles 

denote pumping and monitoring well locations; square denotes location of RM-6. The hydraulic 

conductivity at RM-6 was obtained from the permit application.
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Figure 7. Storage coefficient values (dimensionless) at regional monitoring wells (circles). 
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Figure 8. Storage coefficient values (dimensionless) from pumping test at Mine Unit 2. Circles 

denote pumping and monitoring well locations; square denotes location of RM-6. 
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Figure 9. Assumed locations of injection (small open circles) and extraction (small filled circles) 

wells at Mine Unit 2. Large open circles denote pumping and monitoring well locations; square 

denotes location of RM-6. 
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Figure 10. Model domain (thick blue line). Thin blue lines are boundaries between regions with 

different grid block spacing, as labeled.
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29

Figure 11. Top elevation (ft) of Unit K. Monitoring well and pumping well locations are shown 

as circles. Note that the plot domain is the model domain in model coordinates.
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Figure 12. Thickness (ft) of Unit K. Monitoring well and pumping well locations are shown as 

circles. Note that the plot domain is the model domain in model coordinates.
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Figure 13. Locations (squares) of pseudopoints. Numerical value to the right of the square is the 

head at the pseudopoint, and the text identifies the monitoring well whose head was used to 

interpolate the head at the pseudopoint. The model domain (thick line) and pumping and 

monitoring well locations and heads are shown for reference.
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Figure 14. Initial head (ft) for the simulation. Heads along the domain boundary are the 

boundary heads. Monitoring well and pumping well locations are shown as circles. Note that the 

plot domain is the model domain in model coordinates.
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Figure 15. Hydraulic conductivity (ft/d) in Unit K. Monitoring well and pumping well locations 

are shown as circles. Note that the plot domain is the model domain in model coordinates.
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Figure 16. Simulated head (ft) at the end of the 50-month ISL mine operation.
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Figure 17. Simulated head (ft) at the end of the 50-month ISL mine operation. Injection wells 

are shown as white circles; extraction wells are shown as white triangles.
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Figure 18. Paths of injected particles during 50-month ISL operations. Injection wells are 

shown as white circles; extraction wells are shown as white triangles.
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Figure 19. Paths of injected particles during the ISL mining operations, restoration operations, 

and an additional 20 years after restoration is completed. Injection wells are shown as white 

circles; extraction wells are shown as white triangles. Red triangles represent the particle 

position at the end of the ISL mining period; green diamonds represent the particle position at the 

end of the groundwater sweep; and magenta hexagons represent the particle position at the end 

of the restoration period. The particles were released at the start of the ISL mining operations.

Injection wells are shown as white circles; extraction wells are shown as white triangles.
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Figure 20. Paths of injected particles during the ISL mining operations, restoration operations, 

and an additional 20 years after restoration is completed. Injection wells are shown as white 

circles; extraction wells are shown as white triangles. Red triangles represent the particle 

position at the end of the ISL mining period; green diamonds represent the particle position at the 

end of the groundwater sweep; and magenta hexagons represent the particle position at the end 

of the restoration period. The particles were released midway (760 days) into the ISL mining 

operations.
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39

Figure 21. Percentage of lixiviant at each position at the end of the ISL mine operations. 

Contour intervals are 1%, 20%, 40%, 60%, and 80%. Injection wells are shown as white circles; 

extraction wells are shown as white triangles. 
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40

 

Figure 22. Percentage of lixiviant at each position at the end of the restoration operations. 

Contour intervals are 1%, 20%, 40%, 60%, and 80%. Injection wells are shown as white circles; 

extraction wells are shown as white triangles. 
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41

Figure 23. Percentage of lixiviant at each position 20 years after restoration was completed. 

Contour intervals are 1%, 20%, 40%, 60%, and 80%. Injection wells are shown as white circles; 

extraction wells are shown as white triangles. 
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42

Figure 24. Model domain for alternative model (thick blue line). Thin blue lines are boundaries 

between regions with different grid block spacing, as labeled.
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43

Figure 25. Paths of injected particles, based on the alternative flow model, during the ISL 

mining operations, restoration operations, and an additional 20 years after restoration is 

completed. Injection wells are shown as white circles; extraction wells are shown as white 

triangles. Red triangles represent the particle position at the end of the ISL mining period; green 

diamonds represent the particle position at the end of the groundwater sweep; and magenta 

hexagons represent the particle position at the end of the restoration period. The particles were 

released at the start of the ISL mining operations. Injection wells are shown as white circles; 

extraction wells are shown as white triangles.
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44

Figure 26. Percentage of lixiviant at each position at the end of the ISL mine operations 

simulated using the alternative model. Contour intervals are 1%, 20%, 40%, 60%, and 80%. 

Injection wells are shown as white circles; extraction wells are shown as white triangles. 
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45

Figure 27. Percentage of lixiviant at each position at the end of the restoration operations 

simulated using the alternative model. Contour intervals are 1%, 20%, 40%, 60%, and 80%. 

Injection wells are shown as white circles; extraction wells are shown as white triangles. 
PAGE 97 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

46

Figure 28. Percentage of lixiviant at each position 20 years after completion of the restoration 

phase simulated using the alternative model. Contour intervals are 1%, 20%, 40%, 60%, and 

80%. Injection wells are shown as white circles; extraction wells are shown as white triangles. 
PAGE 98 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

Endnotes

1 See “In Situ Mining Research,” Proceedings of the Bureau of Mines, 

Technology Transfer Seminar, Denver, Colo., August 5, 1981, mines.

az.gov/DigitalLibrary/usbm_ic/USBMIC8852InSituMining.pdf. 

Accessed August 25, 2011. See also BuMines IC8777, “Uranium InSitu Mining in the United States,” 1978, babel.hathitrust.org/cgi/

pt?id=mdp.39015078453639. Accessed August 25, 2011. For industry 

perspective, see Wyoming Mining Association, “In-Situ Recovery,” 

WMA website, wma-minelife.com/uranium/uranium.html. Accessed 

August 25, 2011. The WMA’s full description of ISL mining is that it is 

“a noninvasive, environmentally friendly mining process involving 

minimal surface disturbance which extracts uranium from porous 

sandstone aquifers by reversing the natural processes which 

deposited the uranium.” See also Bill Boberg, “Uranium Mining by InSitu Recovery (ISR) Technology,” Ur-Energy, Inc., 2006, nma.org/pdf/

uranium/060409_in_situ.pdf. Accessed August 25, 2011.

2 U.S. Environmental Protection AgencyEPA, Review of 40 CFR 192,

May 27, 2010 , epa.gov/rpdweb00/tenorm/REVIEW40CFR192.htm. 

Accessed August 25, 2011.

3 EPA has stated in public meetings that it does not expect to issue even 

a draft until early 2012.

4 For the Colorado rules, see Colorado Mined Land Reclamation Board, 

Mineral Rules and Regulations of the Colorado Mined Land Reclamation Board for Hard Rock, Metal, and Designated Mining Operations, 

State of Colorado, Effective September 30, 2010, mining.state.co.us/

rulesregs/HardRockRulesAdoptedAug122010EffSep30.pdf. Accessed 

August 25, 2011. The issue of states’ adopting improved mining laws 

for regulating conventional uranium recovery is a matter that is not 

addressed in detail in this paper. As an example, both New Mexico 

(in 1994) and Colorado (in 2008) improved the legal and regulatory 

framework of uranium recovery in their respective states. It should be 

noted that Colorado’s mining rules have been challenged by industry. 

See “Powertech Challenges State’s Uranium Mining Rules,” North 

Colorado Business Report, November 11, 2010, ncbr.com/article.

asp?id=54553. Accessed August 25, 2011.

5 U.S. Government, Abandoned Mined Lands Portal, a federal partnership of several agencies with cross-cutting jurisdiction, abandonedmines.gov/p.html. Accessed August 25, 2011. With respect to the scale 

of the cleanup necessary for uranium mines, the U.S. government 

states: “The uranium mining industry began in the U.S. in the 1940s 

primarily to produce uranium for weapons and later for nuclear fuel. 

Although there are about 4,000 mines with documented production, 

the EPA—with information provided by other federal, state, and tribal 

agencies—has identified 15,000 mine locations with uranium occurrence in 14 western states. Most of those locations are found in Colorado, Utah, New Mexico, Arizona, and Wyoming, with about 75 percent of those on federal and tribal lands. The majority of these sites 

were conventional (open-pit and underground) mines.“ Abandoned 

Mined Lands Portal, “Abandoned Uranium Mines,” abandonedmines.

gov/wbd_um.html. Accessed August 25, 2011. 

6 EPA has stated in public meetings that it does not expect to issue even 

a draft until early 2012.

7 U.S. Government, Abandoned Mined Lands Portal, a federal 

partnership of several agencies with cross-cutting jurisdiction, 

abandonedmines.gov/p.html. Accessed August 25, 2011. With respect 

to the scale of the cleanup necessary for uranium mines, the U.S. 

government states: “The uranium mining industry began in the U.S. 

in the 1940s primarily to produce uranium for weapons and later for 

nuclear fuel. Although there are about 4,000 mines with documented 

production, the EPA—with information provided by other federal, 

state, and tribal agencies—has identified 15,000 mine locations with 

uranium occurrence in 14 western states. Most of those locations are 

found in Colorado, Utah, New Mexico, Arizona, and Wyoming, with 

about 75 percent of those on federal and tribal lands. The majority of 

these sites were conventional (open-pit and underground) mines.“ 

Abandoned Mined Lands Portal, “Abandoned Uranium Mines,” 

accessed August 25, 2011, abandonedmines.gov/wbd_um.html. 

8 The Uranium Mill Tailings Radiation Control Act (UMTRCA), 

discussed infra at 14, and 68-69, directs EPA to set standards for 

protection of the environment and public health for uranium 

recovery, which are found at 40 CFR 192. Those regulations have not 

been fully updated for two decades. 

9 U.S. Energy Information Administration, Uranium Marketing Annual 

Report, May 31, 2011, eia.gov/uranium/marketing. 

10 For the Colorado rules, see Colorado Mined Land Reclamation 

Board, Mineral Rules and Regulations of the Colorado Mined Land 

Reclamation Board for Hard Rock, Metal, and Designated Mining 

Operations, State of Colorado, Effective September 30, 2010, mining.

state.co.us/rulesregs/HardRockRulesAdoptedAug122010EffSep30.

pdf. Accessed August 25, 2011. The issue of states’ adopting improved 

mining laws for regulating conventional uranium recovery is a matter 

that is not addressed in detail in this paper. As an example, both 

New Mexico (in 1994) and Colorado (in 2008) improved the legal and 

regulatory framework of uranium recovery in their respective states. 

It should be noted that Colorado’s mining rules have been challenged 

by industry. See “Powertech Challenges State’s Uranium Mining 

Rules,” North Colorado Business Report, November 11, 2010, ncbr.

com/article.asp?id=54553. Accessed August 25, 2011.

11 See U.S. Government, Abandoned Mined Lands Portal, “Abandoned 

Uranium Mines.”

12 William L. Chenoweth, “Historical Review of Uranium Production 

from the Todilto Limestone, Cibola and McKinley Counties, New 

Mexico,” New Mexico Geology 7 (November 1985): 82-83, geoinfo.nmt.

edu/publications/periodicals/nmg/downloads/7/n4/nmg_v7_n4_

p80.pdf. Accessed August 25, 2011.

13 U.S. Department of Energy/EIA, Uranium Industry Annual 1994 (July 

1995): viii., ftp://ftp.eia.doe.gov/nuclear/047894.pdf. Accessed August 

25, 2011.

14 Id., p. ix. 

15 42 U.S.C. § 2011, et seq., law.cornell.edu/uscode/42/usc_

sec_42_00002011----000-.html. According to the NRC, “In general 

terms, ‘source material’ means either the element thorium or the 

element uranium, provided that the uranium has not been enriched 

in the isotope uranium-235. Source material also includes any 

combination of thorium and uranium, in any physical or chemical 

form, or ores that contain by weight one-twentieth of one percent 

(0.05 percent) or more of uranium, thorium, or any combination 

thereof. Depleted uranium (left over from uranium enrichment) is 

considered source material.” nrc.gov/materials/srcmaterial.html. 

Accessed August 25, 2011.

16 42 U.S.C. § 2092, law.cornell.edu/uscode/42/2092.html. Accessed 

August 25, 2011.

17 63 NRC 510, 512-13 (2006). 

18 See Train v. Colorado Public Interest Research Group, 426 U.S. 

1, 1976, supreme.justia.com/us/426/1/case.html. Accessed 

August 25, 2011. The real-world effect of this patchwork of laws 

has engendered dismay. In describing the actions of the Interior 

Department, George Arthur, Chairman of the Resources Committee 

of the Navajo Nation Council, testified: “The Department of the 

Interior has been in the pocket of the uranium industry, favoring 

its interests and breaching its trust duties to Navajo mineral 

owners.” Testimony of the Honorable George Arthur, Chair of the 

Navajo Tribal Council Resources Committee, before Oversight and 

Government Reform Committee of the United States House of 

Representatives, October 23, 2007, oversight-archive.waxman.house.

gov/documents/20071127163605.pdf. Accessed August 22, 2011. See 

also Chairman Arthur’s testimony, 2, citing McClanahan v. Hodel, 

No. Civ. 83-161-M, 14 Indian L. Rep. 3113 (D.N.M. 1978), appeals 

dismissed, vac. as moot, nos. 87-1186 and 87-1234 (10th Cir. 1988). 

This case invalidated fraudulently obtained uranium leases approved 

by the Bureau of Indian Affairs (BIA) and observed who observed? that 

“the BIA and Interior generally seem to have been more concerned 

throughout the leasing processing with their relationship with Mobil 

[the uranium lessee] than their relationship with the Indian owners.” 

19 Atomic Energy Act of 1954, as Amended (hereinafter “AEA”), 

found in Nuclear Regulatory Legislation, NUREG-0980, Vol. 
PAGE 99 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

1, No. 9, 111th Cong., 2nd Sess., January 2011, 7-233, nrc.gov/

reading-rm/doc-collections/nuregs/staff/sr0980/v1/sr0980v1.

pdf#pagemode=bookmarks&page=5. Accessed August 25, 2011.

20 See EPA, ”Technologically-Enhanced, Naturally-Occurring 

Radioactive Materials From Uranium Mining” (hereinafter “TENORM 

Report”), 2-1. April 2008. Volume 1 can be found at epa.gov/

rpdweb00/docs/tenorm/402-r-08-005-voli/402-r-08-005-v1.pdf and 

Volume 2 at epa.gov/radiation/docs/tenorm/402-r-08-005-volii/402-

r-08-005-v2.pdf. Accessed August 25, 2011.

21 A comprehensive treatment of the types of wastes found at the 

conventional mining and milling sites would significantly extend 

the length of this report. Therefore we refer the reader to an excellent 

summary of the volume and characteristics of uranium mining and 

milling waste. See EPA, TENORM Report, 3-1–3-31. April 2008.

22 The EPA describes “tailings” as follows: “Wastes produced by the 

extraction or concentration of uranium or thorium from any ore 

processed primarily for its source material content is defined by 

Section 11e.(2) of the Atomic Energy Act as byproduct material. 

That material is not considered to be TENORM in the U.S., and is 

regulated by the NRC or its Agreement States. Under UMTRCA, 

the NRC must utilize EPA environmental protection standards to 

develop its regulations for active and inactive uranium milling and 

extraction facilities. The NRC does not have regulatory authority over 

conventional type uranium mine wastes.” Id., Appendix IV, AVI-5.

23 For a thorough treatment of federal responsibility for the uranium 

mill tailings cleanup, see Paul Robinson, “Uranium Mill Tailings 

Remediation Performed by the U.S. DOE: An Overview.” Southwest 

Research & Information Center, May 18, 2004, sric.org/U_Mill_

Tailing_Remediation_05182004.pdf. Accessed August 25, 2011.

24 For the full text of this law, see Nuclear Regulatory Legislation, 111th 

Congress, 2nd Session, NUREG-0980, Vol. 1, No. 9, January 2011, 503-

526, nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0980/v1/

sr0980v1.pdf. Accessed August 25, 2011.

25 See U.S. Department of Energy/EIA, “U.S. Uranium Production 

Facilities: Operating History and Remediation Cost Under Uranium 

Mill Tailings Remedial Action Project as of 2000,” January 11, 2005,

eia.doe.gov/cneaf/nuclear/page/umtra/title1map.html. Accessed 

August 25, 2011. See also EPA, TENORM Report, Vol. 1, 4-15–4-18. 

We have not yet identified an entirely comprehensive assessment of 

uranium mining and milling’s legacy costs, but this EPA report, which 

relies on the report from the U.S. Department of Energy, Energy 

Information Agency (hereinafter “DOE/EIA”), is one of the few efforts 

we have discovered that make an attempt at a comprehensive tally of 

some of the costs.

26 EPA, TENORM Report, Vol. 1, 4-15–4-20. Here the EPA presents some 

cost data for reclaiming uranium mines and milling facilities. Costs 

can vary dramatically from site to site and will be dependent on a 

host of factors. 

27 James H. Clarke and Frank L. Parker, Vanderbilt University, “Uranium 

Recovery and Remediation of Uranium Mill Tailings: Russian and 

U.S. Experience,” from Cleaning Up Sites Contaminated With 

Radioactive Materials, International Workshop Proceedings, 

Glenn E. Schweitzer, Frank L. Parker, and Kelly Robbins, editors, 

Committee on Cleaning Up of Radioactive Contamination: Russian 

Challenges and U.S. Experience, Office for Central Europe and 

Eurasia Development, Security, and Cooperation, Policy and Global 

Affairs, National Research Council of the National Academies, in 

cooperation with the Russian Academy of Sciences, the National 

Academies Press, Washington, D.C., nap.edu/openbook.php?record_

id=12505&page=69; at 73. Accessed August 25, 2011.

28 Francie Diep, “An ‘Overwhelming Problem’ in the Navajo Nation,” 

Scienceline, December 30, 2010, scienceline.org/2010/12/an-

%E2%80%9Coverwhelming-problem%E2%80%9D-in-the-navajonation/. Accessed August 25, 2011. Here an EPA official states that 

just assessing the uranium mines in the Navajo Nation costs the EPA 

about $12 million every year, and that remediation would cost “in the 

hundreds of millions.” Another reference source for ongoing cleanup 

information that is frequently updated is the World Information 

Service on Energy (hereinafter “WISE”) Uranium Project website. For 

the basic home page, see wise-uranium.org/indexu.html#UMMCI. 

Accessed August 25, 2011. For more extensive treatments of 

decommissioning sites in the United States, regardless of the 

regulator and usefully presented by state, see “Decommissioning 

Projects—USA” (last updated December 21, 2010), wise-uranium.org/

udusa.html. Accessed August 25, 2011. And for uranium Superfund 

sites, see EPA, earlier references attribute this to “U.S. Government” 

Abandoned Mined Lands Portal, epa.gov/aml/index.htm. Accessed 

August 25, 2011. Administered by the EPA, Superfund is the 

government’s program to clean up uncontrolled hazardous waste 

sites.

29 By 1990, mine production of uranium had dropped to 5.9 million 

pounds of U3

O8; production continued throughout the 1990s and 

early 2000s at even lower levels. With the exception of larger declines 

in the early 1990s (in 1992, mines produced 1 million pounds) and 

early 2000s (in 2003, mines produced 2.2 million pounds), uranium 

production from mines has stayed at around 4 million pounds of 

U3

O8 a year for the past two decades. DOE/EIA, “Uranium Industry 

Annual 1992,” 60, tonto.eia.doe.gov/FTPROOT/nuclear/047892.pdf. 

Accessed August 25, 2011. See also DOE/EIA, “Summary Production 

Statistics of the U.S. Uranium Industry,” July 15, 2010, eia.doe.gov/

cneaf/nuclear/dupr/usummary.html. Accessed August 4, 2011.

30 Environmental Working Group, U.S. Mining Database, 2007, ewg.org/

sites/mining_google/US/analysis.php. Accessed August 22, 2011.

31 uxc.com/data/uxc_AboutUraniumPrices.aspx. Accessed August 4, 

2011. incomplete info.

32 “Fast Breeder Reactor Programs: History and Status,” Research 

Report 8, International Panel on Fissile Materials, February 2010, p. 6, 

ipfmlibrary.org/rr08.pdf. Accessed August 25, 2011.

33 Ux Consulting Company, “UxC Nuclear Fuel Price Indicators 

(delayed),” uxc.com/review/uxc_Prices.aspx. Accessed August 4, 

2011.

34 See, for example, the carefully worded statement of the International 

Atomic Energy Agency on the subject: “As we look to the future, 

presently known resources fall short of demand. However, if 

significant and timely exploration is conducted and sufficient 

resources are discovered, there could be an adequate supply of lower 

cost uranium to satisfy demand. Nevertheless, if the exploration 

effort is insufficient, or is not implemented in a timely manner, it 

will become necessary to rely on very high cost conventional or 

unconventional resources to meet demand as the lower cost known 

resources are exhausted. Therefore, to ensure maximum utilization of 

newly discovered resources, exploration must begin relatively soon.” 

International Atomic Energy Agency, 2001, “Analysis of Uranium 

Supply to 2050,” www-pub.iaea.org/MTCD/publications/PDF/

Pub1104_scr.pdf, at 5. Accessed August 25, 2011.

35 I.A. Matthews and M.J. Driscoll, “A Probabilistic Projection of 

Longterm Uranium Resource Costs,” Center for Advanced Nuclear 

Energy Systems, Massachusetts Institute of Technology, June 2010, p. 

25, web.mit.edu/mitei/docs/spotlights/nuclear-fuel-cycle-nfc-119.

pdf. accessed when?

36 DOE/EIA, “Summary Production Statistics of the U.S. Uranium 

Industry,” July 15, 2010. 

37 DOE/EIA, “Annual Energy Review 2009,” p. 279, Table 9.3, “Uranium 

Overview, Selected Years, 1949-2008,” eia.doe.gov/emeu/aer/pdf/

pages/sec9_7.pdf. Accessed August 25, 2011. See also DOE/EIA, 

“Uranium Industry Annual 1992,” October 1993, p. 38, Table 17, 

“Uranium Concentrate Production by State, 1947-1992,” tonto.

eia.doe.gov/FTPROOT/nuclear/047892.pdf, and DOE/EIA, “Total 

Production of Uranium Concentrate in the United States, 1996-3rd 

Quarter 2010,” November 9, 2010, eia.doe.gov/cneaf/nuclear/dupr/

qupd_tbl1.html. Accessed August 25, 2011.

38 “World Uranium Mining” (updated April 2011), world-nuclear.org/

info/inf23.html.

39 DOE/EIA, “Domestic Uranium Production Report,” July 15, 2010, eia.

gov/cneaf/nuclear/dupr/dupr.html. Accessed August 25, 2011.

40 EPA, “Uranium Location Database Compilation,” August 2006, epa.

gov/rpdweb00/docs/tenorm/402-r-05-009.pdf. accessed when?

41 See Manuel Quinones, “Uranium: Va. Becomes Ground Zero 

for Mining Efforts,” E&E Daily, May 27, 2011, eenews.net/

Greenwire/2011/05/27/2 (subscription required). 

42 Natural Resources Defense Council, “Uranium ISL Mine Database,” 

Table 2, 20-27.
PAGE 100 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

43 DOE/EIA, “Uranium Purchased by Owners and Operators of U.S. 

Civilian Nuclear Power Reactors by Origin Country and Delivery Year,” 

Table 3, August 18, 2010. eia.doe.gov/cneaf/nuclear/umar/table3.

html. Accessed August 25, 2011.

44 Southwest Research and Information Center, “Is There a Need for 

New Uranium Mines in the U.S.?” Voices From the Earth 10 (Spring 

2009): 5, sric.org/voices/2009/v10n1/Need%20for%20New%20U%20

Mines.pdf. Accessed August 25, 2011.

45 WNA, “World Uranium Mining,” April 2011, world-nuclear.org/info/

inf23.html. Accessed August 25, 2011.

46 Korea Electric Power Corp. (Kepco) may invest up to $45 million in 

exchange for a 40 percent interest in a Canadian company’s Gas Hills 

uranium properties in Wyoming. Under a binding agreement with 

Vancouver-based Strathmore Minerals Corp. announced on August 

5, 2011, the companies set the terms for a possible joint venture for 

the exploration and development of the Gas Hills Beaver Rim area 

and for a pre-feasibility study for the entire Gas Hills project, activities 

that constitute Phase I of the project. Kepco would invest at least $10 

million during Phase I. Upon Phase I’s completion, Kepco would have 

the option to invest up to another $35 million in Phase II in exchange 

for 40 percent ownership of the entire Gas Hills project. Platts Nuclear 

News Flashes, August 8, 2011 (subscription required).

47 eia.gov/forecasts/aeo/source_nuclear.cfm. 

48 See Table 2 for NRC listing of active and proposed uranium recovery 

operations that will be licensed and regulated by the NRC. 

49 Southwest Research and Information Center, “Uranium Mining & 

Milling: A Primer,” The Workbook 1, orig. document says “Vol. IV” Nos. 

6 and 7 (Nov./Dec. 1979): 225-226, sric.org/uranium/1979_SRIC_

URANIUM_PRIMER.pdf. Accessed August 25, 2011. 

50 DOE/EIA, “Decommissioning of U.S. Uranium Production Facilities,” 

1995, 11-14. atomictraveler.com/MillDecommissioningData.pdf. 

Accessed August 25, 2011. See also infra Figure 2 on 12.

51 For more information on conversion, enrichment, and fabrication 

processes as they relate to the weapons production program, see 

DOE, Office of Environmental Management, “Nuclear Weapons 

Production Processes and History,” Chapter 2 in Linking Legacies, 

January 1997, em.doe.gov/Publications/linklegacy.aspx. Accessed 

August 25, 2011.The topic of restoration of uranium mills is not 

discussed in any depth in this report. 

52 Institute for Energy and Environmental Research (hereinafter “IEER”), 

“Uranium: Its Uses and Hazards,” July 2005, ieer.org/fctsheet/

uranium.html. Accessed August 25, 2011.

53 For a thorough treatment of mine wastes, see EPA, TENORM Report, 

Vol. 1, Chapter 3, “Volume and Characteristics of Uranium Mine 

Wastes.” We also briefly discuss some of the environmental harms 

associated with conventional uranium recovery, infra in Chapter 2. 

54 Peter Diehl, “Uranium Mining and Milling Wastes: An Introduction,” 

WISE Uranium Project, August 15, 2004, wise-uranium.org/

uwai.html#TAILCHAR. Accessed August 25, 2011. The tailings at 

conventional mines and their radioactive and toxic characteristics 

are also described in detail in the EPA TENORM Report, Vol. 1, 3-29: 

“Wastes are primarily disposed of in the form of a slurry composed 

of tailings, gangue (defined as the valueless minerals in an ore; 

that part of an ore that is not economically desirable but cannot 

be avoided in mining. It is separated from the ore minerals during 

concentration) (including dissolved base metals), spent beneficiation 

solutions, and process water bearing carbonate complexes (alkaline 

leaching) and sulfuric acid (acid leaching), sodium, manganese, 

and iron. The characteristics of this waste vary greatly, depending 

on the ore, the beneficiation procedure, and the source of the water 

(fresh or recycled). The liquid component is usually decanted and 

re-circulated to the crushing/grinding or leaching circuit. Tailings 

typically consist of two fractions, sands and slimes. The sand and 

slimes may be combined and deposited directly in the impoundment 

or may be distributed through a cyclone such that the sand fraction is 

directed toward the dam while the slimes are directed to the interior 

of the pond (Merritt 1971). The fate of radionuclides is of special 

interest in uranium mill tailings. Radium-226 and thorium-230 

are the principal constituents of concern and are associated with 

the slime fraction of the tailings. Radon-222 (gas) is also a tailings 

constituent. The concentrations of radionuclides in the tails tailings?

will vary depending on the leach method used (thorium is more 

soluble in acid than alkaline leaches). Typically, tailings will contain 

between 50 and 86 percent of the original radioactivity of the ores 

depending on the proportion of radon lost during the operation. 

Other tailings constituents (including metals, sulfates, carbonates, 

nitrates, and organic solvents) would also be present in the tailings 

impoundment depending on the type of ore, beneficiation methods, 

and waste management techniques.” 

55 EPA, “Uranium Location Database Compilation,” August 2006, p. 6, 

Table 2. 

56 SRIC, “Church Rock Spill: 30 Years Later,” Voices From the Earth 

10 (Summer 2009): 6, sric.org/voices/2009/v10n3/voices_10_3_

churchrock_spill_30yrs.pdf. Accessed August 25, 2011.

57 EPA, “Addressing Uranium Contamination in the Navajo Nation,” 

epa.gov/region9/superfund/navajo-nation/index.html. Accessed 

November 8, 2011.

58 DOI, EPA, NRC, DOE, and Indian Health Services, “Health and 

Environmental Impacts of Uranium Contamination in the Navajo 

Nation,” a report requested by the House Committee on Oversight 

and Government Reform, June 9, 2008, 4-12, epa.gov/region9/

superfund/navajo-nation/pdf/NN-5-Year-Plan-June-12.pdf. 

Accessed August 25, 2011. 

59 See note 17 for discussion of 2008 House Oversight Committee 

Hearings and Navajo testimony. 

60 Robert G. McSwain, testimony on the health and environmental 

impact of uranium mining on the Navajo Nation before the House 

Committee on Government Oversight and Reform, October 23, 2007, 

hhs.gov/asl/testify/2007/10/t20071023e.html. Accessed August 25, 

2011. 

61 F.D. Gilliland et al., “Uranium Mining and Lung Cancer Among 

Navajo Men in New Mexico and Arizona, 1969 to 1993,” Journal of 

Occupational and Environmental Medicine 42 (March 2000): 278-283, 

journals.lww.com/joem/Abstract/2000/03000/Uranium_Mining_

and_Lung_Cancer_Among_Navajo_Men_in.8.aspx (subscription 

required). Accessed August 25, 2011. See also Arjun Makhijani et al., 

Nuclear Wastelands: A Guide to Nuclear Weapons Production and Its 

Health and Environmental Effects, MIT Press, 1995. serc.carleton.

edu/research_education/nativelands/navajo/humanhealth.html. 

Accessed August 25, 2011. 

62 “Resolution of the 20th Navajo Nation Council—Third Year, 2005: 

Relating to Resources and Diné Fundamental Law; Enacting the Diné 

Natural Resources Protection Act of 2005; Amending Title 18 of the 

Navajo Nation Code,” sric.org/uranium/DNRPA.pdf. August 25, 2011

63 Testimony of the Honorable George Arthur, Chair of the Navajo 

Tribal Council Resources Committee, before the Oversight and 

Government Reform Committee of the United States House of 

Representatives, October 23, 2007, oversight-archive.waxman.house.

gov/documents/20071127163605.pdf. Accessed August 25, 2011.

64 EPA, Superfund web portal, updated January 3, 2011, epa.gov/

superfund/. Accessed August 25, 2011.

65 F2, Inc., “Five-Year Review Report: Fourth Five-Year Review Report for 

Uravan Uranium Project (Union Carbide Corp.),” September 2010, p. 

19, epa.gov/superfund/sites/fiveyear/f2010080003616.pdf. Accessed 

August 25, 2011. 

66 See original EPA placement of Uravan on the National Priorities 

List, 51 Fed. Reg. 21054, 21063 (June 10, 1986) and State of Colorado 

oversight of the project at cdphe.state.co.us/hm/rpuravan.htm. 

Accessed August 22, 2011.

67 See babel.hathitrust.org/cgi/pt?id=mdp.39015078453639. Accessed 

August 25, 2011.

68 See Figure 2 for a visual representation of the extent to which 

domestic ISL recovery has supplanted domestic conventional mining 

for the production of U.S. uranium.

69 DOE/EIA, “U.S. Uranium Mine Production and Number of Mines and 

Sources,” July 15, 2010, eia.doe.gov/cneaf/nuclear/dupr/umine.html. 

“Domestic Uranium Production Report—Quarterly (3rd Quarter),” 

November 9, 2010, eia.doe.gov/cneaf/nuclear/dupr/qupd.html. 

World Nuclear Association (hereinafter “WNA”), “World Uranium 

Mining,” updated May 2010, world-nuclear.org/info/inf23.html. 

Accessed August 25, 2011.
PAGE 101 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

70 See Appendix B. Rosanna M. Neupauer, “Degradation of Groundwater 

Quality From Uranium In-Situ Leach Mining,” May 1, 2009. where 

can this paper be accessed? Was it published? See also Edgar B. 

Heylmun, “Roll Front Deposits,” International California Mining 

Journal’s Prospecting and Mining Journal 73 (October 2003), icmj2.

com/03Oct/03OctFeature.htm. Accessed August 25, 2011. 

71 See Appendix A. 

72 EPA TENORM Report, Vol. 1, 2-9. 

73 Heylmun, “Roll Front Deposits.” 

74 State of Texas, “Nuclear Energy,” window.state.tx.us/specialrpt/

energy/nonrenewable/nuke.php. Accessed August 22, 2011.

75 Molly Mechtenberg-Berrigan, “Radioactive Danger in Drinking 

Water,” Nukewatch Pathfinder, Fall 2005, p. 9, nukewatchinfo.org/

Quarterly/20053fall/page9.pdf. 

76 EPA, TENORM Report, Vol. 1, 3-10. 

77 Dustin Bleizeffer, “Water, Spill, Traffic Top Citizens’ Concerns,”

Wyoming Star-Tribune, September 30, 2010, trib.com/business/

energy/article_764aae9c-f584-5bce-8fa4-de2de1dc3568.html. 

Accessed August 25, 2011.

78 EPA, TENORM Report, AV, 11-17. 

79 OECD Nuclear Energy Agency and IAEA, Environmental Remediation 

of Uranium Production Facilities, OECD Publishing, February 27, 

2002, 277. 

80 See 10 CFR 51.45 for the general requirements for an applicant’s 

Environmental Report, nrc.gov/reading-rm/doc-collections/cfr/

part051/part051-0045.html. See 10 CFR 51.60 for the requirements 

for Environmental Reports–Materials Licenses, nrc.gov/reading-rm/

doc-collections/cfr/part051/part051-0060.html. Accessed August 25, 

2011.

81 See “Contention 8 of the Petition to Intervene and Request for 

Hearing of the Oglala Sioux Tribe,” before the United States Nuclear 

Regulatory Commission, Atomic Safety and Licensing Board, at 34. 

Filed April 6, 2010, wba.nrc.gov:8080/ves/view_contents.jsp.

82 That is, if a prescient member of the public (1) filed original 

contentions at the earliest possible moment of the licensing process 

and essentially put in “placeholder” NEPA contentions years in 

advance, (2) amended those contentions almost immediately once 

the draft EIS was issued, and (3) amended the contentions for a 

potential third time if the final EIS addressed positions not previously 

identifiable from the draft. See 10 CFR 2.323(a), nrc.gov/reading-rm/

doc-collections/cfr/part002/part002-0323.html. Accessed August 

25, 2011. This is an onerous and expensive process in the extreme for 

public interest groups. For a full discussion, see Anthony Z. Roisman, 

“Regulating Nuclear Power in the New Millennium (The Role of the 

Public),” Pace Environmental Law Review 26 (Summer 2009): 342, 

digitalcommons.pace.edu/cgi/viewcontent.cgi?article=1556&context

=envlaw. Accessed August 25, 2011.

83 Id., 342. 

84 NRC, Final GEIS, nrc.gov/materials/uranium-recovery/geis.html. 

Accessed August 25, 2011.

85 Draft GEIS, July 2008, xxxiii. The draft GEIS is available on the NRC 

ADAMS website at nrc.gov/reading-rm/adams.html; search the 

database with the accession number ML082030186.

86 NRC, GEIS, xxxv-xxxvi. 

87 See NRDC Comments on Lost Creek, Moore Ranch, and Nichols 

Ranch Supplemental EISs, discussion at 4-7, pbadupws.nrc.gov/docs/

ML1008/ML100850378.pdf. Accessed August 25, 2011.

88 See Appendix A.

89 Id., 1. 

90 Id., 16.

91 See Appendix A.

92 See NRC, “Standard Review Plan for In Situ Leach Uranium Extraction 

License Applications, Final Report,” June 2003, NUREG-1569 

(hereinafter “SRP’), 6-9: “The primary goal of a restoration program 

is to return the water quality within the exploited production zone 

and any affected aquifers to pre-operational (baseline) water quality 

conditions. Recognizing that in situ leach operations fundamentally 

alter ground-water geochemistry, restoration activities are not likely 

to return ground-water quality to exact water quality that existed at 

every location prior to in situ leach operations” (emphasis added), 

nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1569/sr1569.pdf.

Accessed August 25, 2011.

93 Neupauer, “Degradation of Groundwater Quality from Uranium 

In-Situ Leach Mining,” May 1, 2009. 

94 See Appendix A. The ability to produce reducing conditions, or 

“redox” potential, is key to understanding how heavy metals in 

aquifers behave. A reduction potential is a measure of the tendency of 

a chemical species to acquire electrons and thereby be reduced. 

95 A.J. Thompson et al., “Generic Environmental Report in Support of 

the Nuclear Regulatory Commission’s Generic Environmental Impact 

Statement for In Situ Leach Uranium Recovery Facilities,” National 

Mining Association, November 30, 2007, nma.org/Attach/NMA%20

Generic%20Enviromental%20Report%20on%20In%20Situ%20Ur%20

Recovery.pdf. 

96 Mark Moxley, Land Quality Division, Wyoming Department of 

Environmental Quality, “Report of Investigation: Power Resources, 

Inc., Smith Ranch–Highland Uranium Project,” November 21, 2007, 

4. EPA has also detailed significant problems. See EPA’s TENORM 

Report, Vol. II, at AIII-8: “In the United States, excursions have been 

frequently detected by the monitoring wells located around the well 

field. One of the more infamous and environmentally problematic 

ISL operations was located at Irigaray, Wyoming. This facility was 

plagued by persistent environmental excursions which began in 

mid-March of 1979, and were not brought under control until early 

July of that same year. The Wyoming Department of Environmental 

Quality reported that these excursions were a result of the neglect of 

injection pressure monitoring as well as testing the integrity of the 

well casings.” 

97 See NRC, Final GEIS, G-128 for this exchange. Agreement States 

are those states that assume NRC regulatory authority under the 

Atomic Energy Act of 1954. See NRC, “Agreement State Program,” 

nrc.gov/about-nrc/state-tribal/agreement-states.html. Accessed 

August 25, 2011. We disagreed with the NRC’s response that such 

information was outside the scope of the NRC’s review. While the 

Agreement States have assumed the NRC’s regulatory responsibility 

for licensing ISL uranium mines, the NRC’s legal obligations are not 

over. Specifically, Section 274j of the AEA (42 U.S.C. § 2021(j)) allows 

for the NRC, after reasonable notice and opportunity for hearing, to 

terminate or suspend all or part of its agreement with the state and 

reassert its licensing and regulatory authority if the agency finds 

it necessary for the protection of public health and safety, or if the 

state failed to comply with specific requirements. Additionally, the 

NRC is periodically required to review Agreement States to assure 

compliance with the law. As one example, the Texas Commission 

on Environmental Quality (TCEQ) regulations in Title 30, Texas 

Administrative Code, Chapters 37 and 336, are reviewed yearly by 

the NRC for equivalency with the NRC rules in 10 C.F.R. § 40. See, e.g.,

NRC, “Compatibility Comment on Texas Final Regulations,” May 13, 

2009, nrc-stp.ornl.gov/special/regs/txregs090513.pdf. See also NRC, 

“Integrated Materials Performance Evaluation Program: Review of 

the Texas Agreement State Program, Final Report,” February 22-

26, 2010, nrc-stp.ornl.gov/reviews/10tx_imp.pdf. Accessed August 

25, 2011. The NRC has yet to exercise its authority to terminate a 

state’s agreement status on account of mismanagement of materials 

licensing.

98 NRC, SRP, 5-37, nrc.gov/reading-rm/doc-collections/nuregs/staff/

sr1569/sr1569.pdf. Accessed August 25, 2011.

99 Id., 5-38. While we understand that the industry attempts to respond 

to horizontal excursions by adjusting the flow rates of the injection 

and extraction wells, the NRC itself acknowledged that vertical 

excursions are more difficult to correct; some persist for years. Yet the 

NRC still refused to comprehensively analyze the past history of leaks. 

See also Final GEIS at 2-48.

100 NRC, Draft GEIS, July 2008, xxxiii.

101 NRC, GEIS, Sections 2.13, 2.4.1.2, and 4.5-12–4.5-14.

102 Id., 4.5-17. 

103 EPA TENORM Report, 4-12. The EPA explains “groundwater sweep” 

as the process “initiated when the uranium concentration in 

the production fluid has dropped to a level where recovery is no 

longer feasible. During groundwater sweep, the lixiviant (sodium 
PAGE 102 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

bicarbonate) is discontinued, but the water is still pumped through 

the recovery wells, displacing contaminated water from the aquifer. 

As the aquifer is diluted in the concentration of the lixiviant, 

groundwater sweep becomes less useful.” 

104 Id., 4.2-26 

105 Id., 4.5-18. 

106 Robert Moran, cited in Oglala Sioux Tribe, “Petition to Intervene 

and Request for Hearing of the Oglala Sioux, Docket Number 

40-9075-MLA“(April 6, 2010), 26-27, powertechexposed.

com/2010.04.06%20PETITION%20TO%20INTERVENE%20AND%20

REQUEST%20FOR%20HEARING.pdf. Accessed August 25, 2011.

107 Id. 

108 Mark T. Anderson and Lloyd H. Woosley. “Water Availability for the 

Western United States—Key Scientific Challenges,” USGS (2005), p. 6, 

pubs.usgs.gov/circ/2005/circ1261/pdf/C1261.pdf. Accessed August 

25, 2011.

109 Id., 17. 

110 Kathleen Miller and David Yates, “Climate Change and Water 

Resources: A Primer for Municipal Water Providers,” AWWA Research 

Foundation and the University Corporation for Atmospheric 

Research (2005). 

111 Natural Resources Defense Council, “In Hot Water: Water 

Management Strategies to Weather the Effects of Global Warming” 

(July 2007), p. vi., nrdc.org/globalWarming/hotwater/hotwater.pdf. 

Accessed August 25, 2011.

112 Working Group I to the Fourth Assessment Report of the 

Intergovernmental Panel on Climate Change, “Climate Change 2007: 

The Physical Science Basis: Summary for Policymakers,” February 

2007, 4-7, pnud.cl/recientes/IPCC-Report.pdf. Accessed August 25, 

2011.

113 Tetra Tech Inc., “Climate Change, Water, and Risk: Current Water 

Demands Are Not Sustainable,” Natural Resources Defense Council, 

July 2010, nrdc.org/globalwarming/watersustainability/. Accessed 

August 25, 2011. For an overview of the Tetra Tech study, and for 

a more detailed description of methodology, see: Tetra Tech., Inc., 

“Evaluating Sustainability of Projected Water Demands Under 

Future Climate Change Scenarios,” July 2010, rd.tetratech.com/

climatechange/projects/nrdc_climate.asp. Accessed August 25, 2011.

114 Id., 11. Tetra Tech defined summer water deficit as the amount by 

which water withdrawal exceeds available precipitation in June, July, 

and August—typically the three warmest months of the year, when 

there is increased municipal, thermoelectric cooling, and irrigation 

demand.

115 Texas Comptroller of Public Accounts, “Liquid Assets: The State 

of Texas’ Water Resources,” January 2009, 1, window.state.tx.us/

specialrpt/water/PDF/96-1360-LiquidAssets.pdf. Accessed August 25, 

2011.

116 Id., 6. 

117 NRC, Final GEIS, Table 2-6.1, 2-32. 

118 Id., Table 2.7-3, 2-36. 

119 We look forward to the forthcoming EPA rulemaking on 40 CFR 

192, discussed 35, in hopes that the agency can rectify the issue of 

available data on ISL uranium mining impacts. 

120 EPA, TENORM Report, Vol. 1, 3-9. 

121 Stephen H. Brown, “Radiological Aspects of Uranium-Solution 

Mining,” Uranium 1 (1982): 37-52.

122 EPA TENORM Report, Vol. 1, 3-10. 

123 Pedro Ramirez, Jr., and Brad Rogers, “Selenium in a Wyoming 

Grassland Community Receiving Wastewater From an In Situ 

Uranium Mine,” U.S. Fish and Wildlife Service, September 2000, p. 

1, fws.gov/mountain-prairie/contaminants/papers/r6715c00.pdf. 

Accessed August 25, 2011.

124 Id., 1. 

125 As noted by a state regulator, “Some of the spills may have little 

impact individually, but cumulatively they might have a significant 

impact on soils and/or groundwater.” Moxley, 4. 

126 See the NRC memorandum for Chairman Jaczko, Commissioner 

Klein, and Commissioner Svinicki, “Staff Assessment of Groundwater 

Impacts From Previously Licensed In-Situ Uranium Recovery 

Facilities,” July 10, 2009, nrc.gov/reading-rm/adams.html, public 

accession number ML091770187. In practice, all regulators—the NRC 

or Agreement States—have allowed relaxation to weaker standards 

or “alternative concentration limits” rather than restoration of all 

parameters to pre-mining water-quality levels, or even to secondary 

standards such as EPA’s Safe Drinking Water Standards. 

127 NRC, Final GEIS, G-89. 

128 See Memorandum for Chairman Jaczko, Commissioner Klein, and 

Commissioner Svinicki, “Staff Assessment of Groundwater Impacts 

From Previously Licensed In-Situ Uranium Recovery Facilities,” July 

10, 2009. 

129 Powertech Inc., Applicant Powertech (USA) Inc.’s Response to 

Petitioner Oglala Sioux Tribe’s Request for a Hearing/Petition 

for Intervention, Docket No. 40-9075-MLA, May 3, 2010, 17, 

powertechexposed.com/2010.05.03%20Powertech%20Response%20

to%20Motion%20to%20Intervene.pdf. Accessed August 25, 2011.

130 The NRC has produced little on the topic beyond the memorandum 

cited in Note 105. Can’t be right; Note 105 is NRC’s GEIS 

131 Reply letter from Joseph F. Thiel, Director of the Division of 

Environmental Programs, Texas Department of Health, to Texas Water 

Commission, Re: Modification to URI Longoria Restoration Table 

for Uranium to 3.0 mg/l, May 29, 1987, 62, pbadupws.nrc.gov/docs/

ML0115/ML011550450.pdf. This letter was submitted as Attachment 

C-10 with Dr. Richard J. Abitz: Written Testimony of Richard J. Abitz 

in Support of Intervenors’ Reply to HRI’s and NRC Staffs’ January 22, 

2001, Responses to Intervenors’ Presentation on HRI’s Restoration 

Action Plan and Cost Estimates, Docket No. 40-8968-ML, May 23, 

2001, available in its entirety at the URL given above. It should be 

noted that in 1987 there was no federal drinking water standard 

for uranium. The EPA promulgated a final uranium drinking water 

standard in 1999; it is 0.030 mg/l, far below the values allowed in this 

instance.

132 States can assume the NRC’s role and act in lieu of the agency 

by assuming Agreement State status under Title II of UMTRCA. 

States that have licensed ISL mines, for example, include Texas and 

Wyoming. As an Agreement State, a state can assume regulation 

of uranium mill tailings and can enact rules equivalent to or more 

stringent than those required by the NRC and the EPA. See 10 

C.F.R. § 150.31, requiring state compliance with any standards 

promulgated by NRC or EPA under UMTRCA. Specifically, Title II 

of UMTRCA focuses on uranium milling facilities operating after 

1978 and established the framework for NRC and Agreement States 

to regulate mill tailings and other wastes at uranium and thorium 

mills licensed by the NRC at the time of UMTRCA’s passage, and to 

adopt subsequent standards set by the EPA. edocket.access.gpo.gov/

cfr_2008/janqtr/pdf/10cfr150.31.pdf. Accessed August 25, 2011. 42 

USC 2092 et seq., and 42 USC 2111 et seq.

133 Crow Butte Resources, Inc., “Additional Stability Monitoring Data for 

Mine Unit 1 Groundwater Restoration Crow Butte Uranium Project,” 

submitted to NRC October 11, 2002, 2-6; Crow Butte Resources, 

Inc., “Mine Unit 1 Groundwater Restoration, Crow Butte Uranium 

Project,” submitted to NRC January 10, 2000, 36. Also, for radium-226 

the limit for radium-226? was set at 229.7 pCi/L. These documents 

can be obtained via an advanced web-based ADAMS search by typing 

“Crow Butte,” “groundwater,” and “restoration” into the document 

content section at wba.nrc.gov:8080/ves/. 

134 Letter from Daniel M. Gillen, Chief of the Fuel Cycle Facilities Branch, 

Division of Fuel Cycle Safety and Safeguards, Office of Nuclear 

Material Safety and Safeguards, to Michael L. Griffin, Manager of 

Environmental and Regulatory Affairs, Crow Butte Resources, Inc., Re: 

License Amendment 15, Crow Butte Resources In Situ Leach Facility 

License No. SUA-1534, Wellfield #1 Restoration Acceptance (TAC NO. 

L52491), February 12, 2003. These documents can be obtained via an 

advanced web-based ADAMS search by typing relevant search terms 

into the document content section at wba.nrc.gov:8080/ves/. 

135 Power Resources, Inc., “Ground Water Restoration Report for the 

Smith Ranch–Highland Uranium Project,” 13. this isn’t exactly how it 

was rendered in first ref (note #100)
PAGE 103 | Nuclear Fuel’s Dirty Beginnings: Environmental Damage and Public Health Risks From Uranium Mining in the American West 

136 NRC, “Technical Evaluation Report: Review of Power Resources, Inc.’s 

A-Wellfield Groundwater Restoration Report for the Smith RanchHighland Project.” incomplete info?

137 Letter to COGEMA: “Review of COGEMA Mining, Inc., Irigaray Mine 

Restoration Report, Production Units 1 through 9, Source Materials 

License SUA-1341 (TAC LU0137).”

138 NRC, “Technical Evaluation Report: Review of COGEMA Mining, Inc., 

Irigaray Mine Restoration Report, Production Units 1 Through 9, 

Source Materials License SUA-1341 (TAC LU0137).”

139 COGEMA Mining, Inc., “Wellfield Restoration Report, Christensen 

Ranch Project, Wyoming,” March 5, 2008, 1-1 and 1-2, 

powertechexposed.com/Wellfield_Restoration_Report_Christensen_

Ranch_Mar_5_2008.pdf. Accessed August 25, 2011.

140 Memorandum for Chairman Jaczko, Commissioner Klein, and 

Commissioner Svincki, “Staff Assessment of Groundwater Impacts 

From Previously Licensed In-Situ Uranium Recovery Facilities” (July 

10, 2009). 

141 Susan Hall, “Groundwater Restoration at Uranium In-Situ Recovery 

Mines, South Texas Coastal Plain,” USGS, 2009, 6, pubs.usgs.gov/

of/2009/1143/pdf/OF09-1143.pdf. Accessed August 22, 2011.

142 Id., 7; Southwest Groundwater Consulting LLC, “Report on Findings 

Related to the Restoration of Groundwater at In-Situ Uranium Mines 

in South Texas,” September 28, 2008, 1 (stating data are “unorganized 

and difficult to navigate”), uraniuminfo.org/files/BK_Darling%20

Report_Complete_Sept_30.pdf. Accessed August 25, 2011.

143 Hall, “Groundwater Restoration at Uranium In-Situ Recovery Mines, 

South Texas Coastal Plain,” 6.

144 Id., 30.

145 Id., 21.

146 Id., 8.

147 Id., 7.

148 Id., 9.

149 Id., 10.

150 Southwest Groundwater Consulting LLC, “Report on Findings Related 

to the Restoration of Groundwater at In-Situ Uranium Mines in South 

Texas,” September 28, 2008, 3 and Attachment A. 

151 Id., 2.

152 Id, 4-5. 

153 Id. 5-6 (based on data from all of the listed mines except O’Hern).

154 See note 2, supra. 

155 If one searches online in the NRC database or visits state offices, 

significant amounts of paper exist, but little of it is compiled in a 

coherent and publicly accessible fashion. Note that when we use the 

word paper we literally mean “paper.” Almost no usable state data 

are online and publicly accessible; for access one must visits relevant 

state offices and pay for copying said paper. Obtaining material 

online from the NRC was complicated further by the less-than-userfriendly ADAMS database that has only recently been updated. For 

example, one can go to the NRC website and find under “nuclear 

materials” and “uranium recovery” a link to an NRC page briefly 

describing the Smith Ranch–Highlands ISL operation or the Crow 

Butte ISL operation. The ADAMS database may contain detailed 

information about an ISL mining site’s multiple contamination 

excursion notices, documents about failures or acceptance of 

weakened groundwater restoration standards, or discussion of the 

adequacy of financial assurance documents. However, to find any 

document, one needs an ”accession number” that identifies the 

individual document. Such a process ensures that a reader will have 

to search repeatedly through potentially hundreds of documents. 

Industry and the federal government have available resources 

and staff to plow through such a process. But few organizations—

including under-resourced state regulators—have the financial 

wherewithal to conduct similar efforts. Obtaining materials from 

relevant state agencies was equally difficult, and not set up for public 

accessibility. First, most states lack funds and therefore do not have 

the resources or staff to place a great deal of regulatory information 

online. Second, while our interactions with individual state staffers 

were uniformly excellent, particularly in Wyoming, regulating 

operations as complex as large ISL sites strains limited state budgets. 

this is so delicately worded, it seems like a non-sequitur in relation 

to first half of sentence. Was something cut? It was considerably 

easier to actually send representatives from SRIC and NRDC to 

offices in Wyoming to locate requested information. Unfortunately, 

when we did find the relevant files, the information was less than 

comprehensive. 

156 Discussed supra at 66-67,check the USGS performed a limited survey 

of ISL aquifer restoration in Texas and had similar experiences in 

terms of locating useful regulatory data.

157 As simple proof of the regulatory mess, DOE authority to perform 

remedial action at these sites—a job that is not yet done—expired in 

1998, except for the authority to perform groundwater restoration 

activities.

158 See note 132 for discussion of Agreement State status and assumption 

of NRC authority. See also 10 C.F.R. § 150.31, requiring state 

compliance with any standards promulgated by the NRC or the EPA 

under UMTRCA, nrc.gov/reading-rm/doc-collections/cfr/part150/

part150-0031.html. Accessed August 25, 2011.

159 See 10 C.F.R. § 40. See also Section 11(z) of the AEA, which states that 

“the term ‘source material’ means (1) uranium, thorium, or any other 

material which is determined by the Commission pursuant to the 

provisions of section 61 to be source material; or (2) ores containing 

one or more of the foregoing materials, in such concentration as the 

Commission may by regulation determine from time to time,” 42 

USC 2014(z). See also Section 11(e) of the AEA , which states that “the 

term ‘byproduct material’ means (1) any radioactive material (except 

special nuclear material) yielded in or made radioactive by exposure 

to the radiation incident to the process of producing or utilizing 

special nuclear material, and (2) the tailings or wastes produced by 

the extraction or concentration of uranium or thorium from any ore 

processed primarily for its source material content,” 42 USC 2014(e). 

160 The EPA has developed guidance—but not regulations—for use 

in cleanup of radioactively contaminated soils and groundwater 

primarily for the Superfund program in “Risk Assessment Guidance 

for Superfund Vol. I: Human Health Evaluation Manual (Part A),” 

EPA/540/1-89/002, epa.gov/oswer/riskassessment/ragsa/pdf/ragsvol1-pta_complete.pdf. Accessed August 25, 2011. The soil standards 

are based on radiation standards developed for the UMTRCA 

program for uranium mills (US EPA 1998, 199c), while cleanup 

standards for groundwater use the EPA’s maximum contaminant 

levels established under the SDWA. The radionuclide soil cleanup 

standard for combined radium-226, radium-228, and thorium-232 is 

5pCi/g. For groundwater cleanup and protection, the EPA drinking 

water standards for uranium, 30 ug/L and 5pCi/L, are the targets.

161 EPA TENORM Report, p. A VI-3. ISL uranium mining commonly 

occurs in U.S. drinking waters. (See EPA, “Underground Injection 

Controls,” water.epa.gov/type/groundwater/uic/wells_class3.cfm. 

Accessed August 25, 2011.) It is therefore subject to the limitations 

established under the UIC program. However, the regulations also 

provide an exemption for some aquifers, 40 C.F.R. §144.7, ecfr.

gpoaccess.gov/cgi/t/text/text-idx?type=simple;c=ecfr;cc=ecfr;rgn

=div5;idno=40;q1=144.7;sid=570ece3e13fd69281543eb220711e66

2;view=text;node=40%3A22.0.1.1.6#40:22.0.1.1.6.1.42.7. Accessed 

August 25, 2011. The EPA has established the following criteria for 

determining whether an injection well qualifies for that exemption. 

To qualify for an exemption, an aquifer cannot “currently serve as 

a source of drinking water,” and it “cannot now and will not in the 

future serve as a source of drinking water” because: (1) considering 

the amount of minerals or hydrocarbons, the location is “expected 

to be commercially producible”; (2) it is located at depth or location 

such that recovery of the water is “economically or technologically 

impractical”; (3) “it is so contaminated that it would be economically 

or technologically impractical to render that water fit for human 

consumption”; or (4) “it is located over a Class III well mining area 

subject to subsidence or catastrophic collapse,” Id., § 146.4(a) – (b).

162 Letter from Brian J. Walsh, Hydrology Specialist, Ground Water 

Quality Program, State of South Dakota Department of Environment 

and Natural Resources, re: Deficiency of Revised Permit Application 

for Dewey-Burdock, April 19, 2010, p. 1, powertechexposed.com/

SD%20DENR%20Class%20III%20UIC%20Permit.htm. Accessed 

August 25, 2011.
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163 See Associated Press, March 15, 2011, “Daugaard Signs Bill Easing 

Uranium Regulations,” posted March 15, 2011, Rapid City Journal

online, rapidcityjournal.com/news/local/article_d3ef1dde-4f50-

11e0-8b6d-001cc4c002e0.html. Accessed August 25, 2011.

164 See NRC, SRP, “Standard Review Plan for In Situ Leach Uranium 

Extraction License Applications, Final Report,” June 2003, nrc.

gov/reading-rm/doc-collections/nuregs/staff/sr1569/sr1569.pdf. 

Accessed August 25, 2011.

165 10 C.F.R. § § 40.42(h)-(k); 10 C.F.R. § 40, Appendix A.

166 In its guidance on the subject (not rules), the NRC candidly 

acknowledges the likelihood of contamination as it recites its primary 

restoration standards: “The primary goal of a restoration program 

is to return the water quality within the exploited production zone 

and any affected aquifers to pre-operational (baseline) water quality 

conditions. Recognizing that in situ leach operations fundamentally 

alter ground-water quality geochemistry, restoration activities 

are not likely to return ground-water quality to exact water quality 

that existed at every location prior to in situ leach operations. Still, 

as a primary restoration goal, licensees are required to attempt to 

return the concentrations of the monitored water quality indicator 

constituents to within the baseline range of statistical variability for 

each constituent.” SRP, 6-9 (emphasis added).

167 In its description of the secondary restoration standards in its 

guidance, the NRC continues with its relatively candid assessment 

of damage to aquifers, but deviates into a point of significant 

controversy by asserting that restoration to class of use is an 

appropriate fallback option. The SRP states: “Secondary Restoration 

Standards—In situ operations may cause permanent changes in 

water quality within the exploited production zone, because the 

in situ leach extraction process relies on changing the chemistry 

in the production zone to remove the uranium. The applicant may 

therefore propose returning water quality to its pre-operational class 

of use (e.g., drinking water, livestock, agricultural, or limited use) as a 

secondary restoration standard.” SRP, 6-9 (emphasis added). Finally, 

the SRP addresses what has become the default decision for ISL 

uranium mines, restoration to “alternative concentration limits.” The 

NRC states: “If a constituent cannot technically or economically be 

restored to its secondary standard within the exploited production 

zone, an applicant must demonstrate that leaving the constituent at 

the higher concentration would not be a threat to public health and 

safety or the environment or produce an unacceptable degradation 

to the water use of adjacent ground-water resources. SRP, 6-9.

168 See endnote 132 for a discussion of Agreement State roles and NRC 

responsibilities. 

169 Jeffrey S. Merrifield, memorandum for Chairman Diaz, Commissioner 

McGaffigan, Commissioner Jaczko, and Commissioner Lyons from 

Commissioner Merrifield, “Regulation of Groundwater Protection 

at In Situ Leach Uranium Extraction Facilities,” January 17, 2006, 

1 nrc.gov/reading-rm/doc-collections/commission/commsecy/2006/2006-0001comjsm.pdf. Accessed August 25, 2011.

170 Id. 

171 Memorandum for Chairman Klein, Commissioner McGaffigan, 

Commissioner Merrifield, Commissioner Jaczko, and Commissioner 

Lyons, “Path Forward for Rulemaking on Groundwater Protection at 

In Situ Leach Uranium Extraction Facilities,” April 30, 2009, 1. 

172 Id., 2. It should be noted that NRDC was not contacted by the NRC to 

reach a consensus on rulemaking strategies, nor, to our knowledge, 

were any other environmental groups contacted.

173 NRC, “Briefing on Uranium Recovery,” March 2, 2010, transcript, 9, 

nrc.gov/reading-rm/doc-collections/commission/tr/2010/20100302.

pdf. Accessed August 25, 2011.

174 Id., 9. 

175 NRC Rulemaking Working Groups, 10 CFR Part 40, In Situ Leach 

Working Group, nrc-stp.ornl.gov/rulemakingwgrps.html. Accessed 

January 25, 2011. 

176 NRC, “Environmental Impact Statement for the Lost Creek ISR 

Project; Supplement to the Generic Environmental Impact Statement 

for In-Situ Leach Uranium Milling Facilities,” NUREG-1910 

Supplement 3, draft report for comment, November 2009, 5-1–5-

13, nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1910/s3/

sr1910s3.pdf. Accessed August 25, 2011.

177 NRC, “Environmental Impact Statement for the Moore Ranch 

ISR Project; Supplement to the Generic Environmental Impact 

Statement for In-Situ Leach Uranium Milling Facilities,” NUREG-1910 

Supplement 1, final report, August 2010. 5-7, nrc.gov/reading-rm/

doc-collections/nuregs/staff/sr1910/s1/sr1910s1.pdf. Accessed 

August 25, 2011.

178 NRC, “Environmental Review Guidance for Licensing Actions 

Associated With NMSS Programs,” final report (NUREG-1748), nrc.

gov/reading-rm/doc-collections/nuregs/staff/sr1748/sr1748.pdf, 4-1 

to 4-14, August 2003. Accessed August 25, 2011.

179 See Nichols Ranch SEIS, 5-1–5-3.

180 Dustin Bleizeffer, “State Seeks Action in Illegal CBM Spill,” Wyoming 

Star-Tribune, February 25, 2010, trib.com/news/state-and-regional/

article_55d3d7d5-dba6-50eb-a3d9-4433dde8c10b.html. Accessed 

August 25, 2011. 

181 Natural Resources Defense Council, “Drilling Down: Protecting 

Western Communities From the Health and Environmental Effects of 

Oil and Gas Production,” (2007), 5, nrdc.org/land/use/down/down.

pdf. Accessed August 25, 2011.

182 Id.

183 See 34-32-112.5. Designated mining operation—rules, 

powertechexposed.com/1161_rerevised_May_2_2008.pdf. Accessed 

November 8, 2011.

184 The issue of states’ adopting improved mining laws for regulating 

conventional uranium recovery is not addressed in detail in this 

paper. As examples, both New Mexico (in 1994) and Colorado (in 

2008) have substantially improved the legal and regulatory framework 

of uranium recovery within their borders.

185 Rep. John Kefalas, Colorado House of Representatives, et al., ”Session 

Law Chapter 252: An Act Concerning an Increase in the Regulatory 

Authority of the Mined Land Reclamation Board Over Mining, and, 

in Connection Therewith, Ensuring the Protection of Ground Water 

and Public Health, and Making an Appropriation,” approved May 20, 

2008, state.co.us/gov_dir/leg_dir/olls/sl2008a/sl_252.pdf. Accessed 

August 25, 2011.