12 Environmental Impacts of Uranium Mining

Although uranium is radioactive in general, its intense radioactivity is limited because the main isotope, U-238, has a half-life that is equal to the age of the earth. U-235 emits alpha particles and gamma rays, and its half-life is one-sixth of this.

Therefore, gamma rays from a piece of pure uranium would be somewhat higher than those from a lump of granite. In practical terms, its alpha radioactivity depends on whether it is present as a dry powder or as a lump (or in rock as ore).

In the latter instance, alpha radiation poses a possible risk, albeit a little one. Chemically speaking, it is similarly poisonous to lead. Gloves are typically used when handling uranium metal as a sufficient precaution. To prevent humans from breathing in or consuming it, uranium concentrate is managed and confined.

Exploration geologists searching for uranium have identified gamma radiation from related elements like bismuth and radium, which have formed throughout geological time as a result of uranium’s radioactive disintegration.

Environmental Impacts of Uranium Mining

The following are some major environmental issues related to uranium mining

• Habitat Disruption
• Soil Degradation
• Water Contamination
• Surface Water Quantity
• Tailings and Waste Management
• Radiation Exposure
• Airborne Contaminants
• Acid Mine Drainage
• Groundwater Contamination
• Energy Intensity
• Land Reclamation Challenges
• Concerns About Nuclear Proliferation

1. Habitat Disruption

The local ecosystems and biodiversity may be impacted by the habitat fragmentation and degradation caused by mining operations. Removing soil and plants may cause disturbances to wildlife habitats.

2. Soil Degradation

The removal of soil and overburdens during mining operations has an immediate impact on the physical, chemical, and biological characteristics of the soil.

Changes in the soil’s ability to supply moisture for plant growth, loss of living organisms essential to healthy soils (e.g., microorganisms and earthworms), loss of viable seed banks with extended storage, loss of soil organic matter and nitrogen, loss of pore space due to compaction and altered soil structure, and altered soil structure are among the most common effects.

These effects are typical of large-scale industrial disturbance in general and contemporary mining operations, not just uranium mining.

The majority of these primary impacts occur within the mining site, and the type of mining used will determine how much of an influence mining activity has on the soil.

Because surface disturbance in underground mining is limited to very modest underground openings, soil consequences are negligible. On the other hand, there is the highest amount of disturbed soil during open-pit mining.

Furthermore, offsite conditions might be impacted by secondary effects, such as the increased water runoff caused by soil compaction that was previously discussed in this section.

3. Water Contamination

Water is frequently used in the extraction and processing stages of uranium mining.

Several reclamation operations, dewatering of mine workings and pits, temporary storage of ores and mining and processing wastes on-site, and disturbance of the land surface caused by mining can all have a significant impact on the concentrations and loads of dissolved and suspended materials in surface water off-site.

Groundwater must be kept out of the mine or extracted through a procedure called dewatering for a mine to be worked.

A series of extraction wells surrounding the mine can be used to lower the local water table and keep water from entering, or groundwater entering the mine can be pumped out and dumped at the surface.

Surface water quality may be impacted by mine dewatering operations, especially if the discharge is left untreated.

A wide range of materials can have an impact on surface water, such as certain nonradioactive substances (particularly dissolved heavy metals and metalloids), naturally occurring radioactive materials (NORM), technologically enhanced naturally occurring radioactive materials (TENORM), and liquid and solid tailings from processing operations.

This may result in the presence of radionuclides, heavy metals, and other contaminants hazardous to human health and aquatic life contaminating neighboring water sources.

4. Surface Water Quantity

It would be expected that Virginian uranium mining sites, whether underground or above ground, would occasionally leak water off-site. One source of control over discharge rates would be

1. Precipitation inputs (such as rainfall intensity).
2. Preceding moisture conditions;
3. Characteristics of the land surface (such as soil infiltration capacity)
4. Accessible water storage (pit storage, detention ponds, etc.)
5. Water is released from mining activities on purpose.

Surface drainage from mined areas would probably be higher locally than from unmined areas covered in natural second-growth forests.

Although the percentage increase would decrease with distance from the mines and the surface water quantity effects from tailings management could be greater, the relative increase in runoff would also result in increases in stream flow in receiving waters downstream.

5. Tailings and Waste Management

One major environmental problem associated with uranium extraction is the disposal of radioactive tailings. Inadequate storage may allow pollutants to infiltrate into the ground and water, resulting in long-term contamination.

The quantity and makeup of the different waste materials, the techniques used to process the uranium ore, how the different waste materials are stored and disposed of, and the actions taken to lessen the impacts on surface water quality will all affect how mine waste and tailings management affect surface waters.

All of the naturally occurring radioactive and non-radioactive elements present in uranium ore, including all of the radionuclides in the uranium decay series, particularly those of 238U, are found in mine and mill tailings.

Even though processing removes 90–95 percent of the uranium in the ore, lowering uranium concentrations by at least an order of magnitude, the majority of the uranium decay products—such as 230Th, 226Ra, and 222Rn—which may account for most of the ore’s radioactivity—remain in the tailings.

The activity of the tailings will essentially not change for many thousands of years due to the long half-life of 230Th (76,000 years).

Given their very lengthy half-lives, the geochemistry and mineralogy of 230Th and 226Ra (1,625-year half-life) are particularly significant from the standpoint of water quality.

6. Radiation Exposure

During mining operations, radioactive elements including radon gas and radionuclides may be discharged, posing a danger of exposure to local populations and personnel.

7. Airborne Contaminants

A uranium mining and processing operation may produce air pollution, particulate matter, and airborne processes that mobilize pollutants.

As with any construction site, during construction, there will be fugitive dust, soil entrainment, and exhaust from construction equipment. Diesel engines, which run construction machinery and vehicles, emit diesel fumes.

To keep workers safe, ventilation devices are needed in underground mines; yet, the air will become polluted with released dust.

The air consequences of subterranean and open-pit mining are different. Through blasting, loading into transport vehicles, and transportation to the processing facility, open-pit mines release dust directly into the atmosphere.

Particulate matter transported off-site has annoying effects like clogged eyesight and dust buildup on vehicles and homes. Particulate matter exposure, however, can potentially worsen asthma, increase ER visits, and even cause lung or heart disease-related death.

Individuals with respiratory disorders, including asthma, bronchitis, emphysema, heart illness, diabetes, newborns, children, and teenagers, are among those at heightened risk.

8. Acid Mine Drainage

If acid mine drainage (AMD) is not properly managed, it can become one of the most dangerous environmental issues brought on by uranium mining.

A population of acidophilic bacteria oxidizes metal sulfides (such as FeS2) found in waste materials or mining to create AMD. Since these bacteria can only survive in acidic environments, the creation of acidity can quicken and eventually become self-sustaining in the presence of sulfides and oxygen.

Acidic mine water has a higher probability of containing heavy metals (such as iron, manganese, aluminum, copper, chromium, zinc, lead, vanadium, cobalt, or nickel) or metalloids (such as selenium or arsenic) released into solution by oxidation of the sulfide minerals, in addition to radionuclides in the uranium-238 (238U) decay series (i.e., uranium, radium, radon, and thorium).

Thus, a precondition that encourages the release of radionuclides and hazardous heavy metals from uranium mines into the environment is the existence of sulfide minerals in the uranium ore.

9. Groundwater Contamination

Groundwater can get contaminated by radioactive and hazardous compounds leaching from uranium mining operations, endangering ecosystems and sources of drinking water.

Through geochemical interactions, groundwater in contact with aquifer solids will acquire a chemical composition that reflects the host rock’s makeup. Numerous geochemical and hydrogeological factors influence the extent of these reactions and, consequently, the chemical composition of the water, such as

• The mineralogy of the host rock
• The size of the mineral grains
• The chemical makeup of the water passing through the aquifer
• How long the water in the aquifer has been there
• The routes of flow (such as fracture flow as opposed to flow via granular porous material).

A number of these factors can be changed by mining operations, which can subsequently affect the groundwater’s quality.

There are two main ways that contemporary tailings management poses a threat to groundwater quality:

• Failure of the structures (such as tailings holding structures, liners, and leak collection systems) intended to prevent toxins from the tailings from entering the nearby groundwater
• Inappropriate hydraulic isolation in below-grade disposal facilities can take many forms, such as inadequate pump failure in active isolation, inadequate understanding of the site hydrogeology, and inadequate compaction of tailings in passive hydraulic isolation.

10. Energy Intensity

Significant energy inputs, frequently from non-renewable sources, are needed for the extraction and processing of uranium, which adds to greenhouse gas emissions and the environmental effects of energy production.

11. Land Reclamation Challenges

After uranium mining, reclaiming land is a complicated procedure. It can take a while for ecosystems to recover and environmental harm to be mitigated, and the pre-mining state might not entirely return. Before the water levels are restored to pre-mining levels, it can take several years or even decades.

Additionally, the disruption of the aquifer brought on by mine construction might permanently alter the patterns of groundwater flow in the area, which might affect the amount of water available for nearby domestic supply wells, though overall this effect is probably going to be negligible.

Reduced rates of groundwater recharge are also likely to occur locally. Topsoil that had been accumulated during the mining operation is replaced on the land during the mine site reclamation procedure.

However, the physical, chemical, and biological characteristics of reclaimed soils differ significantly from those of natural soils, and some of these discrepancies can take up to 1,000 years to heal.

For example, the natural soil horizons that form over hundreds to thousands of years are erased when topsoil is removed, piled, and replaced.

Compaction, leaching, and biological deterioration of the nutrients produce changes in the physical, chemical, and biological properties of stockpiled topsoil, which leads to its decline.

Changes in nitrogen cycling in such soils during stockpiling result in the loss of nitrogen reserves in topsoil that were subsequently renewed after being stockpiled.

Furthermore, the microbial population (fungi and bacteria) in stockpiled soils has undergone long-term alterations that have changed how they operate when mine sites are restored in comparison to pre-mining conditions or unmined areas.

12. Concerns About Nuclear Proliferation

Because mined uranium may be used to produce nuclear weapons, uranium mining raises questions regarding the spread of nuclear weapons.

Conclusion

To lessen these negative effects on the environment, mining operations must use best practices, stringent regulations must be developed and put into place, and cutting-edge technologies for waste management and water treatment must be used.

Reducing the long-term environmental effects of uranium mining requires sustainable mining methods and safe handling of radioactive products.

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