Life of a Uranium Mine in Canada - CNSC Online

Uranium Mining in Canada

Uranium Mining in Canada

Table of contents

Uranium Mining in Canada

Life of a Uranium Mine in Canada

Vigilance Throughout the Lifecycle of a Mine
For Safe and Responsible Mining Operations

Uranium Mine in Canada

Life of a Uranium Mine in Canada

As a mine progresses through its lifecycle, the CNSC works closely with provincial inspectors at every step to make sure the many people who work there are safe from radiation and other job hazards. We also make sure that the project is safe for the environment—now and into the future.

  • Site Preparation
  • Construction
  • Operations
  • Decommissioning
  • Release from Licence
 
A graphic representation of the five license stages.
 

Uranium Mining in Canada

Site Preparation and Construction

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A mine site under construction with 4 clickable hotspots.

Site Preparation and Construction

Before construction of a new mine or mill the licensee must collect air, water and soil samples to establish background or natural levels. During the construction and operation phases air, water and soil samples are collected and compared to these background levels.

The Rabbit Lake mill under construction.

Site development continues at Rabbit Lake as the mill undergoes modernization

Water Sampling

Water samples are collected to determine background or natural levels. Samples collected during the mining and milling phases and decommissioning are then compared to these background or natural levels. Water samples are collected in lakes, rivers and streams near the proposed mine or mill and also further away.

Uranium workers taking water samples.

Water samples are taken as part of a continuous process to ensure environmental discharges remain below limits to protect lakes and rivers

Mine Access Shaft

Some underground mines require a mine shaft to access the uranium ore located beneath the surface. Shafts are developed or "sunk" into the ground followed approved plans by the CNSC.

The main McArthur River head frame.

The main McArthur River head frame houses the hoist over the main shaft which delivers miners and equipment as deep as 680 metres below surface

Construction

Buildings and facilities are needed on the surface to support the underground mine. These are constructed using modern standards following CNSC review.

The Cigar Lake site construction

Cigar Lake site construction

Drilling

Before and during the development of a uranium mine diamond drilling is completed. The drilling can be completed on the surface or underground. The drilling determines the location of the ore, the grade of the ore and is also used to assess ground stability near the uranium ore.

A core sample drill.

Drilling core samples

Parts of a Uranium Mine - 6

Uranium Mining in Canada

Mining Operations - Radiation and Air Quality Monitoring

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An underground mining site with 7 clickable hotspots.

Radiation Monitoring and Air Quality

During the operation of a uranium mine radiation monitoring is an important part of the daily activities. Samples are collected underground to make sure that the work areas are safe for workers. Samples on the surface are regularly collected to ensure the levels are below limits and the workers and the public are protected.

The underground at Cigar Lake.

After underground workings were dewatered at Cigar Lake in early 2010, ventilation systems were restored to ensure miners remain protected from radon exposure

Radon samples collected near mine exhausts

Ventilation is used to control concentrations of radon in the mine. Because of radon underground, uranium mines require above average air flow compared to other types of mines. Radon and mine exhaust air is released into the air and quickly dispersed. The radon level is so low that it cannot be detected within a few kilometres of the exhaust.

The McArthur mine site.

McArthur River Mine - the exhaust fans can be seen in the foreground

Air Sampling

Samples are collected on the surface to make sure that levels are below regulatory limits.  The samples are analyzed for both hazardous and nuclear substances.

A uranium worker taking an environment sample.

A uranium worker takes an environment sample

Grab Sampling by worker

Daily samples are collected underground by radiation technician's to monitor the radiation levels. Workers are only permitted to work in areas where the radiation levels are well below regulatory limits. Radiation technicians also check to make sure that workers are wearing their radiation monitoring equipment.

A uranium worker taking an air sample.

A radiation specialist checking for any evidence of radon gas near the raise bore mining machine. The raise boring process itself helps to separate miners from direct contact with the ore body

Radiation Monitoring

Radiation monitoring is a very important part of underground mining. Daily samples are collected by technicians and continuous radon monitors let workers know if the area is safe for work.

A radon monitoring machine.

Continuous radon monitoring

Shotcrete Application

In some parts of the mine the walls and floor can contain uranium ore which gives off radiation. Shotcrete is a concrete that is sprayed through a hose onto the walls and the floor of the mine to provide a layer of shielding and protection from the radiation.

A uranium worker applying shotcrete shielding.

Application of shotcrete shielding

Remote Mucking

Some uranium mines use remote control equipment. This equipment is used to help reduce the workers exposure to radiation. By keeping a distance between the worker and the source of the radiation (uranium ore) the worker's exposure is reduced.

A worker using a remote controlled front-end loader.

Worker using remote controlled front-end loader.

Freeze Wall

At some uranium mines a "freeze wall" is used. This technology is used at uranium mines with very high groundwater flows and unstable ground. The "freeze wall" creates a shield around the uranium ore so that it can be extracted safely as it is separated from the groundwater.

A uranium worker checking the freeze pipes.

Active freeze pipes with chilled brine running through them

Uranium Mining in Canada

Mining Operations - Waste Management and Waste-rock

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An underground mining site with 4 clickable hotspots.

Waste Management and Waste-rock

Waste rock must be managed to prevent environmental impact. Two priorities for managing waste rock are to reduce the amount produced in the first place and to reuse the material where possible.

Trucks hauling uranium ore and mineralized waste.

Trucks hauling uranium ore and mineralized waste to surface

Environmental Monitoring

Effluent is released into the environment after it has been treated in a water treatment plant and tested to ensure it is below regulatory limits. The effluent is sampled as it is released and further downstream. These results are compared to regulatory limits and background levels. Fish, sediment, berries, soil, plants and animal samples are collected on a regular schedule to confirm that these local foods can still be consumed by local residents.

Wildlife in a northern river.

Samples are collected from many sources to garantee levels are below allowable limits

Ongoing Reclamation

Managing Waste Rock Piles - Throughout the development and operation of the mine waste rock piles must be managed. Once the pile is no longer needed or has reached its maximum size the pile can be decommissioned.

A waste rock pile re-seeded with local grasses, shrubs and trees.

A waste rock pile re-seeded with local grasses, shrubs and trees

Leachate Monitoring

Monitoring Waste Rock Piles - Waste rock that contains hazardous chemicals are stored on a lined pad to keep the chemicals away from the environment. The water that runs through the waste rock pile is called leachate. This leachate is collected and treated in the water treatment plant. Clean waste does not require a lined pad as leachate is not produced.

Leachate on a holding pad.

Leachate monitoring on waste and ore rock piles

Groundwater Monitoring

Groundwater samples are collected, analyzed, and the results are compared to background levels. Groundwater monitoring occurs throughout the site, including near waste rock piles.

A worker conducting water sample analysis.

Groundwater monitoring near waste rock piles

Uranium Mining in Canada

Mining Operations - Water Treatment

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An underground mining site with 4 clickable hotspots.

Water Treatment

Water used in the uranium mining process is called effluent and must be treated before it is released into the environment. Water treatment plants use various chemicals and processes to treat the effluent to make sure that the effluent meets regulatory limits. CNSC staff regularly inspect water treatment plants and review effluent quality.

An aerial photo of the Key Lake Mill.

Aerial view of Key Lake Mill showing effluent ponds

Downstream Sample Collections

Effluent is released into the environment after it has been treated in a water treatment plant and tested to ensure it is below regulatory limits. The effluent is sampled as it is released and further downstream. These results are compared to regulatory limits and background levels. Fish, sediment, berries, soil, plants and animal samples are collected on a regular schedule to confirm these local foods can still be consumed by local residents.

A uranium worker collecting a downstream water sample.

Collecting a water sample downstream from the operations

Monitoring Effluent Quality

Any water used at the mine site must be treated before it can be discharged into the environment. The water treatment plant removes the impurities from the contaminated water to purify it before it is released to the environment. Effluent is sampled, analyzed and compared to regulatory limits before it is released.

A worker collecting an effluent water sample.

Worker collecting a water sample as effluent is discharged into the environment

Water Treatment Plant

Any water used at the mine site must be treated before it can be discharged into the environment. The water treatment plant removes the impurities from the contaminated water to purify it before it is released to the environment.

The water treatment system at Key Lake.

Reverse osmosis water treatment plant at Key Lake

Groundwater Monitoring

Groundwater is monitored. Samples are collected, analyzed, and the results are compared to background levels. Groundwater monitoring occurs throughout the site, including near waste rock piles.

A worker conducting water sample analysis.

Worker conducting water sample analysis

Uranium Mining in Canada

Milling Operations

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A uranium milling operation with 6 clickable hotspots.

Milling Operations

The CNSC conducts inspections and reviews to make sure that workers involved in transportation of uranium are properly trained to handle, package, and transport uranium. There are strict regulatory requirements for all shipments of uranium, from uranium ore to the final shipments of yellowcake.

A CNSC inspector taking a gamma measurement from a barrel of yellowcake.

CNSC inspector takes a gamma measurement from a barrel of yellowcake

Yellowcake Truck

Barrels of yellowcake are loaded into transport trucks or shipping containers and are shipped to customers for further processing. The trucks can not carry any other products when they are shipping yellowcake. Truck drivers are trained in emergency response.

A yellowcake barrels.

Yellowcake barrels prepare to be shipped for further processing

Mill

Uranium that is separated from the ore in the milling process it is called yellowcake. Milling uses chemical processes to create yellowcake which has the consistence of fine sand and is packed into barrels.

The inside of Key Lake uranium mill.

The inside of Key Lake uranium mill

Slurry Truck

High grade uranium is transported from a mine to a mill as a slurry in specially designed containers. Slurry is similar to a sand water mixture.

A slurry truck arriving at the Key Lake mill.

McArthur River high grade ore arrives as a slurry in special totes after being trucked 80 kilometres south to the Key Lake mill

Dump Truck

Dump trucks are used to transport mineralized waste and uranium ore with low concentrations to the mill for processing. They can be quite large in the case of open pit mining or they can be smaller for mineralized waste.

Dump trucks transporting ore at an open pit mine.

Dump trucks transporting ore at an open pit mine

Transport Roads

Transport trucks carrying yellowcake travel along provincial and federal highways to ship the yellowcake to customers for further processing. These roads are monitored for erosion through the various provincial entities.

A uranium ore slurry truck.

Uranium ore slurry truck

Tailings Management

One method of tailings management is placing the tailings in mined out pits. These pits specially prepared with drains and pumping systems. As the tailings solidify, the liquid portion is released to a drain located at the bottom of the pit. The water that drains away is pumped to the mill, treated and released as effluent to the environment. This type of facility provides natural, long-term containment of the tailings which can be decommissioned.

An in-pit tailings storage with water cover.

In-pit tailings storage with water cover

Uranium Mining in Canada

Shutdown and Decommissioning

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A decommissioned uranium mining site with 5 clickable hotspots.

Shutdown and decommissioning

Before a mine or mill can be shut down it must be decommissioned. During decommissioning the buildings are removed, the tailings and waste rock are secured and stabilized. Open pits are infilled or flooded and underground mines are closed and backfilled with concrete caps.

Workers planting trees at a decommissioned mine site.

The site is re-vegetated with local trees, bushes and grasses, an ongoing activity within overall remediation strategy

Downstream Monitoring

Environmental monitoring continued after a mine or mill is decommissioned. Samples of water, air and sediment are collected and compared to regulatory limits and background levels. As the levels return to background levels, the frequency of sample being collected will be reduced.

A photo of berries.

Fish, berries, soil, plants and animal samples are collected on a regular schedule to confirm that these local foods can still be consumed by local residents

Concrete Pad

Underground mine openings are filled with rock and are closed with a concrete cap similar to a driveway.  These concrete caps will be assessed after decommissioning and replaced as required.

A concrete pad at a decommissioned mine site.

Covering the underground mine openings with concrete ensures that the mine cannot be accessed

Clean Waste Rock

Clean waste rock is left in place and local grasses, trees and shrubs are planted. Mineralized waste rock is placed in mined out pits or covered with an engineered cover to reduce the amount of water that can come in contact with the rock.

A decommissioned waste rock pile.

A decommissioned waste rock pile

Air Monitoring

Air quality monitoring continues after a mine or mill is decommissioned. Samples are collected and analyzed for hazardous or nuclear substances and compared to regulatory limits and background levels. After decommissioning radon levels quickly return to background levels. As the levels return to background levels, the frequency of sample being collected will be reduced.

A diffusion type radon detector.

Passive, diffusion type radon detector

Groundwater Monitoring

Groundwater is monitored after a site has been decommissioned. Samples are collected, analyzed and the results are compared to background levels. As the levels return to background levels, the frequency of sample being collected will be reduced.

A CNSC inspector taking water quality measurements.

A CNSC inspector takes water quality measurements to ensure effluent release standards set out by the CNSC are met at a decommissioned mine site

Uranium Mining in Canada

Long-term Environmental Monitoring

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A released uranium mining site with 4 clickable hotspots.

Long-term Environmental Monitoring

Environmental monitoring takes place for years after a site is decommissioned. Long after a mine or mill is decommissioned, the CNSC and provincial or territorial governments continue to make sure that the site is safe for the public. Financial guarantees are put in place to make sure of this. (Financial guarantees are bonds that are held with the government to cover decommissioning costs.)

Quirke mine site after decommissioning.

Quirke mine site after decommissioning

Long-term Water Monitoring

Environmental monitoring continues after a mine or mill is decommissioned over the long term. Samples of water, sediment and fish are collected and compared to regulatory limits to confirm that these have returned to background levels.

Wild salmon in a lake.

Fish, berries, soil, plants and animal samples may continue to be collected to confirm that these local foods can still be consumed by local residents

Long-term Monitoring of Waste Rock

Long term monitoring of both waste rock and clean rock is required. The sites are inspected regularly to make sure that the piles are stable and there is no significant erosion or ground movement near the pile. The plants, shrubs and trees that were planted are inspected to make sure they continue to grow and develop.

CNSC staff inspecting a decommissioned mine and mill site.

CNSC staff inspecting the decommissioned Beaverlodge mine and mill site

Long-term Air Quality Monitoring

Radon samples may continue to be collected well into the long term to confirm that the levels remain at background levels.

A worker collecting an air sample.

Worker collects an air sample

Long-term Monitoring of Groundwater

Long-term groundwater monitoring may continue to be collected well into the future to compare the results to background levels.

A worker collecting groundwater samples.

Worker collects groundwater samples