Sabahat Khan

Sangita Jain

Michael Dudas

Timothy Mulrooney

Ryan Connors

Tate Sullivan

Andrew J. Wittmann

Andy Wittmann

Justin Hauke

Tim Mulrooney

- On **October 7, 2025**, Tetra Tech, Inc. announced the promotion of **Roger R. Argus** to **President** of the Company, reporting to Chairman and CEO Dan L. Batrack.  **[831641_0001104659-25-097567_tm2528147d1_8k.htm:0]** **[831641_0001104659-25-097567_tm2528147d1_ex99-1.htm:0]** 
- In his new role, Mr. Argus will **oversee Tetra Tech's global operations**.  **[831641_0001104659-25-097567_tm2528147d1_8k.htm:0]** **[831641_0001104659-25-097567_tm2528147d1_ex99-1.htm:0]** 
- Mr. Argus has been with Tetra Tech for **over 30 years**, previously serving as Executive Vice President, Corporate Development, and President, Commercial/International Services Group.  **[831641_0001104659-25-097567_tm2528147d1_8k.htm:0]** **[831641_0001104659-25-097567_tm2528147d1_ex99-1.htm:0]** 
- **Jonathan S. Weiss** has been appointed **President, Commercial/International Services Group (CIG)**, bringing over 30 years of experience at Tetra Tech.  **[831641_0001104659-25-097567_tm2528147d1_ex99-1.htm:0]**

Tetra Tech Announces Leadership Appointments

- The **Patterson Lake South (PLS) Project** has an updated Net Present Value (NPV) of **US$1,325 million** (8% real discount rate, post-tax) at a **US$90/lb U3O8** price assumption.  **[831641_b3462e58bbc14193a445d046bc638790_0]** **[831641_b3462e58bbc14193a445d046bc638790_2]** 
- Updated Front-End Engineering and Design (FEED) stage pre-production capital costs are estimated at **US$1,226 million**.  **[831641_b3462e58bbc14193a445d046bc638790_0]** **[831641_b3462e58bbc14193a445d046bc638790_1]** 
- Average life of mine (LOM) cash operating costs are estimated at **US$11.7/lb U3O8**, and average LOM all-in sustaining costs (AISC) are estimated at **US$15.2/lb U3O8**.  **[831641_b3462e58bbc14193a445d046bc638790_0]** **[831641_b3462e58bbc14193a445d046bc638790_1]** 
- First uranium production at the PLS Project is targeted for **2031**.  **[831641_b3462e58bbc14193a445d046bc638790_0]** **[831641_b3462e58bbc14193a445d046bc638790_2]** 
- The Engineering Review, which included an updated FEED stage cost estimate developed by **Tetra Tech Canada Inc.**, confirms the technical robustness of the PLS Project.  **[831641_b3462e58bbc14193a445d046bc638790_1]**

Paladin Energy provides update on PLS Project Engineering Review

TETRA TECH (TTEK)