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. In the past, the waste rock produced by underground and open pit mining was piled up outside the mine. This practice has caused problems, including on Navajo lands where more than half of the small, abandoned uranium mines from the middle of the 20 th century and their wastes remain.
Wind can blow radioactive dust from the wastes into populated areas and the wastes can contaminate surface water used for drinking. Some sites also have considerable groundwater contamination. Underground mines can present a radiation hazard to miners. Without proper air ventilation, 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. To protect the public near uranium mines, vented radon gas must not exceed certain limits. Sometimes miners are required to wear respirators that protect their lungs from radon gas. Learn more about the health effects of radon at Radon in Homes, Schools and Buildings. 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. The EPA relies on several regulations and laws to protect people and the environment from radiation exposure from the uranium extraction process. The Clean Air Act limits the amount of radon that can be released from tailings impoundments and underground uranium mines. Runoff water from mines, mills, and ore piles is regulated under the Clean Water Act.
The Safe Drinking Water Act sets limits for radionuclides in drinking water. Some uranium mining and milling sites are cleaned up under the EPA Superfund program. Summary of the Clean Water Act This webpage provides a summary of the Clean Water Act and provides links to information about the statute.
Uranium can be found in soils and waters due to the breakdown weathering of rocks containing it. Once it is in the soil and water, it can be taken up by plants and consumed by people or grazing animals, or it can dissolve in the water to be consumed by any organism.
Uranium deposits occur in many different rock types from sedimentary to volcanic. One thing almost all economic uranium deposits have in common is that the uranium is remobilized from one area ie.
Uranium can be found in a large number of minerals WebMineral has an excellent listing of them in order of uranium concentration. The most common economic minerals are listed below click on the links to see photos and additional information on these minerals :.
This slurry is then mixed with sulfuric acid or an alkaline solution to release the uranium from the host rock. From this acid or alkaline solution, uranium oxide or yellowcake is precipitated. This is still not the purest form, and the uranium has to be sent to another plant to enrich it. The remaining rock slurry is pumped to a tailings dam.
These tailings are exposed to the surface and heavy metals can be released into the environment. While not all uranium ore deposits are amendable to ISR, it is the preferred method to extract uranium since it is far cheaper to get the ores out of the ground and it is considered more environmentally friendly than traditional underground or open pit mines. Elsewhere in the world, like Australia and Kazakhstan, sulfuric acid is used, and remediation has not been required.
This is not an acceptable technology in the U. Any mention or link regarding a product, organization, company, or trade name is for information only and does not imply endorsement by the Bureau, NMT, or the State of New Mexico see more.
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