Mr. Leigh Curyer reports

NEXGEN ANNOUNCES PROVINCIAL APPROVAL AND COMMENCEMENT OF 2023 SITE INFRASTRUCTURE AND CONFIRMATION PROGRAM: ENHANCING SAFETY AND CREATING JOBS FOR LOCAL COMMUNITIES

The Saskatchewan Ministry of Environment has approved the commencement of the 2023 site infrastructure and confirmation program (SI&CP) at NexGen Energy Ltd.'s 100-per-cent-owned Rook I project in the Athabasca basin, Saskatchewan. The SI&CP comprises a comprehensive field program focused on infrastructure upgrades to support increased activity and continued engineering data confirmation for the project.

Consistent with all work conducted to date at the project, maximizing local participation remains a key focus through the 2023 SI&CP, prioritizing employment and business opportunities for indigenous and community members. The SI&CP will generate an increase in NexGen's on-site work force by more than 60 full-time-equivalent personnel, with the majority of the work force including contractors and service providers representing the local priority area. NexGen is budgeted to spend approximately $35-million on SC&IP activities during 2023.

Leigh Curyer, chief executive officer, commented: "The commencement of the 2023 site infrastructure and confirmation program represents another exciting advancement for NexGen and the surrounding communities in Saskatchewan's Athabasca basin. The work reflects NexGen's ongoing commitment to ensuring elite standards in health, safety, environment, and quality while expanding infrastructure to support long-term economic and social activity in the region. As the company transitions into this next exciting phase of project execution, we are pleased to be building on the success of NexGen's 2022 geotechnical program as we confirm our understanding of the site conditions of the future production and exhaust shafts, which will optimize project development and shaft sinking activities."

site infrastructure program 2023 overview

The 2023 site infrastructure program includes expanding and upgrading existing infrastructure, as well as constructing new infrastructure to support increased activities on the project in the coming years. The 2023 site infrastructure upgrades are focused on supporting increased personnel at the project while maintaining NexGen's elite health, safety, environment and quality (HSEQ) standards.

Key aspects include:

• Expansion and upgrade of temporary camp facilities:
  • Engineering, procuring and installing hard-walled modular camp facilities to increase capacity from 100 to 200 beds on site;
  • Expanding and upgrading the waste water and water treatment facilities to support an increased work force on site, including upgrading the water treatment system to provide potable water on site and reducing reliance on procurement of potable water for site personnel.
• Site access improvements:
  • Conducting road upgrades along the 13-kilometre site access road and existing on site roads to optimize worker and user safety, material handling and equipment transport efficiencies. Planned activities include adding turnout and staging areas, brushing to improve line of sight and culvert extension/installation to maintain effective water management.
• Patterson Creek bridge upgrades:
  • Widening the effective running surface and increasing the load capacity of the existing bridge to support increased use. A prefabricated steel structure was selected to optimize the use of existing infrastructure and minimize environmental disturbance during installation.

site confirmation program 2023 overview

The 2023 site confirmation program will build on NexGen's highly successful 2022 geotechnical program and support project engineering as it transitions from front-end engineering design (FEED) into detailed engineering. The 2023 site confirmation program will be focused on gathering additional information at the planned shaft locations, which are critical path aspects of the overall project.

Key aspects include:

• Temporary freeze hole drilling:
  • Drilling of the production and exhaust shaft temporary freeze rings, including pressure and monitoring wells, comprising up to 59 holes to a maximum depth of 220 metres below surface. Detailed information will be collected through the freeze hole drilling program to validate ground conditions to inform the thermal modelling and freeze ring designs for detailed engineering.

Detailed engineering and procurement for the SI&CP is progressing and on track for the commencement of site work in the spring of 2023.

About NexGen Energy Ltd.

NexGen Energy is a Canadian company focused on delivering clean energy fuel for the future. The company's flagship Rook I project is being optimally developed into the largest low-cost producing uranium mine globally, incorporating the most elite environmental and social governance standards. The Rook I project is supported by a National Instrument 43-101-compliant feasibility study which outlines the elite environmental performance and industry-leading economics. NexGen is led by a team of experienced uranium and mining industry professionals with expertise across the entire mining life cycle, including exploration, financing, project engineering and construction, operations, and closure. NexGen is leveraging its proven experience to deliver a project that leads the entire mining industry socially, technically and environmentally. The project and prospective portfolio in Northern Saskatchewan will provide generational long-term economic, environmental and social benefits for Saskatchewan, Canada and the world.

NexGen is listed on the Toronto Stock Exchange, the New York Stock Exchange and on the Australian Securities Exchange, providing access to global investors to participate in NexGen's mission of solving three major global challenges in decarbonization, energy security and access to power. The company is headquartered in Vancouver, B.C., with its primary operations office in Saskatoon, Sask.

Technical disclosure

All technical information in this news release has been reviewed and approved by Kevin Small, NexGen's senior vice-president, engineering and operations, a qualified person under National Instrument 43-101. A technical report in respect of the feasibility study is filed on SEDAR and EDGAR, and is available for review on NexGen Energy's website.

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