Uranium Mining and Milling

About uranium and why it is mined

Uranium is a naturally occurring radioactive element used for fuel in nuclear power reactors. Canada, one of the world's largest uranium producers, accounts for 18 percent of global production and exports 90 percent of its uranium.

Uranium is mined so it can be processed at a milling facility in order to recover the uranium concentrate. The uranium concentrate is then shipped to processing and fabrication facilities that create fuel for nuclear power reactors.

How is the uranium mining and milling industry regulated?

The Canadian Nuclear Safety Commission (CNSC) regulates and licenses all existing and proposed uranium mining and milling operations in Canada. The CNSC manages this industry's licensing, certification and compliance, in accordance with the requirements of the Nuclear Safety and Control Act (NSCA) and its Regulations, which reflect Canadian and international safety standards. The CNSC and its staff focus on health, safety, security and the environment, and ensure Canada implements its international obligations on the safe use of nuclear materials.

No person may prepare a site for, construct, operate, decommission or abandon a uranium mine or mill without first applying for and receiving a CNSC licence.

Who regulates surface exploration for uranium?

Each province or territory is responsible for regulating and monitoring exploration activities within its jurisdiction, and for informing the public about them. Uranium exploration poses the same low risks to public health or the environment, as any exploration methods (such as drilling small core samples). It does not significantly modify the natural environment. Uranium exploration presents a very low risk of increasing radiation or radon exposure to the public and to the environment.

For more information on uranium exploration regulations and guidelines in your area, please contact your provincial or territorial government.

What type of waste do uranium mines and mills produce?

Mine waste rock and tailings are two of the main types of waste that result from uranium mining and milling.

• Clean waste rock and waste rock: Mining produces both clean waste rock and waste rock that must be removed to retrieve the uranium ore. Clean waste rock is not harmful to the environment and is placed in surface rock piles for future use. Waste rock is usually found close to the ore body and contains low concentrations of radionuclides or heavy metals (mineralized waste). These must be managed during operations and properly disposed of so that contaminants are not released to the environment.
• Tailings: Milling uranium ore produces tailings. Tailings are what is left over once the uranium has been removed from the ground rock and resemble fine sand. They contain long-lived radionuclides (such as thorium-230 and radium-226) produced from the decay of uranium, as well as trace metals like arsenic and nickel. They also contain chemical residues from the milling process.

How is waste from uranium mines and mills regulated and managed?

Canada's long-standing experience in uranium mining has resulted in stringent regulations and world-leading practices for the protection of health and safety of persons and the environment. These practices have evolved over time to reflect changes in scientific knowledge as well as the public's expectations.

Clean waste rock, waste rock and uranium mill tailings are typically stored on the mining or milling sites themselves. Clean waste rock from the mining operation is usually placed in rock piles and segregated from waste rock as it is mined. Clean rock can be used in construction as concrete or in the building of roads. Clean waste rock that is left over once mining has ceased is left in piles on the earth's surface, contoured to fit in with the natural environment and re-vegetated.

Waste rock is usually stored temporarily on the earth's surface, in piles that have collection systems to treat water that may run off or filter through the piles. After mining is completed, waste rock can be placed back in the environment from which it was mined, used as backfill in underground mines, or placed in a mined-out pit. It can also be left on the surface and placed under an engineered cover to reduce water infiltration.

How does the CNSC ensure a mine is closed down safely?

The final stage for a mine or mill is its shutdown, decommissioning and end-state environmental monitoring. The CNSC requires a licensee to have a financial guarantee in place during all phases of the facility's lifecycle to cover the cost of decommissioning. This ensures that decommissioning is included in planning at all stages in a facility's lifecycle. Decommissioning and reclamation plans for mines and mills must be assessed and approved by the CNSC before work can proceed.

For example, there are former uranium mining and milling sites in Saskatchewan, Ontario and the Northwest Territories. These inactive sites are being managed in the long term by their former owners or the federal, provincial or territorial government. Long after a mine is decommissioned, the CNSC and provincial/territorial regulators continue to verify that the licensee complies with all licence conditions and regulatory requirements to ensure long-term stability.