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Rook I project

The Impact Assessment Act (IAA) came into force August 28, 2019. Ongoing projects with environmental assessments initiated under the Canadian Environmental Assessment Act, 2012 (CEAA 2012) and led by the CNSC, will continue under their current processes. The IAA contains provisions to enable these projects to advance in this way.


Environmental assessment (EA) start date:  May 2, 2019
Reference number:  80171
Proponent: NexGen Energy Ltd.
Location: Patterson Lake, Saskatchewan

Visit the Canadian Impact Assessment Registry (CIAR) website for all information and documentation related to the project.

Latest update

About the project

On March 15, 2019, the CNSC received a project description from NexGen Energy Ltd. for the issuance of a licence to construct and operate a new uranium mine.

NexGen Energy Ltd. is proposing to develop an underground uranium mine on the Patterson Lake peninsula in the southwestern Athabasca Basin in northern Saskatchewan, approximately 155 km north of the town of LaLoche, Saskatchewan.

The proposed Rook I project includes underground and surface facilities to support the mining and processing of uranium ore. The main components include underground mine development; an onsite mill to process an average of 1,400 tonnes of ore per day; surface facilities to support the short- and long-term storage of waste rock and ore; an underground tailings management facility; water-handling infrastructure and an effluent treatment circuit; and additional infrastructure to support mining activities.

CNSC authorization in the form of a licence issued under subsection 24(2) of the Nuclear Safety and Control Act (NSCA) is required in order for the project to proceed.

Before the Commission can consider an NSCA licensing decision regarding NexGen Energy Ltd.’s proposal, an EA conducted under the Canadian Environmental Assessment Act, 2012 is required. The purpose of an EA is to identify the possible environmental effects of a proposed project, and determine whether these effects can be mitigated and whether there are any remaining significant adverse environmental effects before the project is allowed to proceed.

Further information

The public registry for this project is maintained on the CIAR. If you wish to receive email notifications when the CNSC’s website is updated, including notices for hearings, meetings and Participant Funding Program funding opportunities, subscribe to the CNSC mailing list. For questions or information directly related to this EA, contact:

Nicole Frigault
Environmental Assessment Specialist

Environmental Assessment Division
Canadian Nuclear Safety Commission
P. O. Box 1046, Station B
Ottawa, ON K1P 5S9
Telephone: 613-995-7948 or 1-800-668-5284
Fax: 613-995-5086

The CNSC regulates the use of nuclear energy and materials to protect the health, safety and security of Canadians and the environment; to implement Canada’s international commitments on the peaceful use of nuclear energy; and to disseminate objective scientific, technical and regulatory information to the public.

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