Uranium Mines and Mills
Uranium is used as nuclear fuel for electric power generation.
• U.S. mining industries can obtain uranium in two ways: mining or milling.
• Mining waste and mill tailings can contaminate water, soil and air if not disposed of properly.
About Uranium Mines and Mills
Uranium is a natural mineral and has been mined and used for its chemical
properties for thousands of years. The U.S. mining industry can retrieve uranium in
two ways: by mining rock that contains uranium or by using strong chemicals to
dissolve uranium from the rock that is still in the ground. When uranium is near the
surface, miners dig the rock out of open pits. Open-pit mining strips away the
topsoil and rock that lie above the uranium ore. When uranium is found deep
underground, miners must dig underground mines to reach it. The rock is then
removed through underground tunnels.
There are three methods for extracting the uranium from the ore: heap-leaching,
in-situ leaching and milling.
Uranium Ore.
Heap-leaching is the process of dissolving a chemical by pouring a liquid on it. One example of this
type of process is making coffee. Uranium heap-leaching is done by spraying chemicals over piles of
crushed rock that contain uranium. Underground drains below the heap collect the uranium-bearing
liquid. Once the liquid is collected, it is sent for additional processing to extract the uranium. U.S.
miners currently do not use this method.
In-situ leaching (also known as in-situ uranium recovery) is Latin for "in place." Some uranium is
found in rocks that are porous and completely soaked with water underneath the nrnunrl In-situ
leaching of uranium is done by pumping chemicals
into the groundwater to dissolve uranium from the
surrounding rock. The liquid containing uranium is
pumped to the surface through wells. The liquid
solution is then processed to recover the uranium.
Currently, this is the most commonly used mining
method in the United States.
Milling is a process that removes uranium from the
rock that contains it. Uranium ore is removed from
open-pit and underground mines. Once at the mill,
the ore is crushed and ground up. Chemicals are
added to dissolve the uranium. The uranium is then
recovered from the chemical solution. Tailings are the
radioactive wastes that are left over from the milling
processes. They can contain uranium, thorium,
Aerial view of the Midnite Mine in Washington
State. This uranium mine is no longer operating.
United States Environmental Protection Agency | Office of Radiation and Indoor Air (6608T) | EPA 402-F-14-005 | August 2014 | p. 1
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An abandoned underground uranium mine.
radium, polonium, lead, radon and chemical wastes
like arsenic and organics. Mill tailings are stored in
specially designed ponds called impoundments.
Uranium eventually decays to radium. Radium decays to
release a radioactive gas called radon. Open pit uranium
milling and in-situ mining sites do not pose a significant
radon risk to the public or to miners; the radon disperses into
the atmosphere. However, underground mines are a greater
radiation hazard to miners. Without precautions, radon can
collect in the mineshafts where it is inhaled by miners. The
operators of uranium mines must take special precautions to
protect miners, such as pumping radon gas out of the mine
and replacing it with fresh air. Radon gas vented from
uranium mines must not exceed certain limits to protect the
public near the mines. It is also necessary for miners to wear
respirators that protect their lungs from radioactive dust and
radon gas.
In the past, the waste rock produced by underground and
open-pit mining was piled up outside the mine. This practice
has caused problems on Navajo lands in particular, where
more than half of the many small, abandoned uranium mines
from the middle of the 20th century and their wastes remain.
Wind can blow radioactive dust from the wastes into
populated areas and the wastes can contaminate drinking
water.
Previously, waste rock and mill tailings were used in some
Western mining areas as building materials for homes,
schools, roads and other construction. Structures built with
waste rock and mill tailings were radon and radiation hazards
to anyone spending time in them. People traveling on roads
made with waste rock were in danger of breathing
radioactive dust. In response to these issues, the 1978
Uranium Mill Tailings Radiation Control Act (UMTRCA)
stopped the use of mill tailings in building and construction
projects. EPA, Navajo EPA and individual states continue to work together to identify and cleanup or rebuild
contaminated buildings and roads.
Rules and Guidance
U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA)
The Uranium Mill Tailings Radiation Control Act (UMTRCA)' enables EPA to set limits on radiation from mill
tailings. The Clean Air Act" also limits the amount of radon that can be released from tailings impoundments
and underground uranium mines. Runoff from mines, mills and ore piles is regulated under the Clean Water
Act"'. The Safe Drinking Water Activ sets limits for radionuclides in drinking water. Uranium mining and milling
sites are cleaned up under the EPA Superfund program.
Mine wastes outside the abandoned Davis
Uranium Mine in Colorado.
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U.S. NUCLEAR REGULATORY COMMISSION (NRC)
NRC licenses and oversees the operations of mills, heaps and in-situ leaching mines. NRC rules for tailings
impoundments are based on EPA limits.
THE STATES
Many states have signed formal agreements with NRC to get authority over the licensing and operations at
mills and in-situ leaching mines. These states are known as Agreement States.
U.S. DEPARTMENT OF LABOR (DOL), MINE SAFETY AND HEALTH ADMINISTRATION (MSHA)
MSHA enforces safety and health rules at mines and mills. These rules help reduce health hazards and
prevent accidents in the nation's mines and mills.
U.S. DEPARTMENT OF ENERGY (DOE)
DOE takes control of closed and reclaimed mills. At the direction of Congress, DOE cleans up mill sites.
U.S. DEPARTMENT OF THE INTERIOR (DOI), BUREAU OF LAND MANAGEMENT (BLM)
BLM manages 262 million acres of land - about one-eighth of the land in the United States. The Bureau
manages about 700 million more acres of underground minerals, including uranium mines. The Office of
Surface Mining provides funds to many state and tribal agencies for cleaning up uranium mines on their land.
U.S. ARMY CORPS OF ENGINEERS (USAGE)
The U.S. Army Corps of Engineers operates the Formerly Utilized Site Remedial Action Program (FUSRAP).
Its job is to identify and clean up old, contaminated facilities that supported the federal government in the early
years of the nation's atomic energy program. Some of these sites have radioactivity levels above today's
regulatory limits. Through the FUSRAP, federal agencies, state and local governments and property owners
work together to keep radioactive material on these sites under control. The Corps of Engineers has also
assisted EPA and tribes in cleaning up abandoned mines on Native American properties.
What you can do
EPA and other agencies work to protect people and the environment from the uranium mining wastes. You can
contact your state geological survey or radiation control office to learn if there are mining wastes in your area.
• Avoid mining sites and their abandoned equipment.
• Do not handle, dispose of or reuse old equipment or materials from uranium mining sites.
You should never:
• Swim in or drink the water from open pit mine lakes.
• Drink the water from streams and springs near abandoned uranium
mines.
• Remove rock or soil from a uranium mine to reuse or as souvenirs.
Where to learn more
You can learn more about radioactive material from uranium mines and mills by visiting the resources available
on the following webpage: http://www.epa.qov/radtown/uranium-mines-mills.htmltflearn-more.
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' http://www.epa.gov/radiation/laws/laws sum.html#umtrca
" http://www.epa.gov/air/caa/peq/
"' http://www2.epa.gov/laws-regulations/summary-clean-water-act
iv http://water.epa.gov/lawsregs/rulesregs/sdwa/
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