DDW-2024-014205

US Magnesium LLC
238 North 2200 West - Salt Lake City, UT 84116-2921
801/532-2043 - 800/262-9624 - FACSIMILE 801/534-1407

Submitted via Email to: [e-mail]

December 9, 2024

State of Utah
Department of Environmental Quality
Division of Drinking Water
P.O. Box 144830
Salt Lake City, UT 84114-4830

RE: US Magnesium Notification of Suspension of Its Rowley Plant’s Status as a Non-Transient,
Non-Community Water System; Water System Number: UTAH23039

To Whom It May Concern:

US Magnesium (USM) suspended magnesium production in September 2022 and subsequently
reduced its headcount at the Rowley plant. Due to depressed global lithium carbonate prices, US
Magnesium has idled its lithium carbonate production process. On September 23, 2024, USM
provided 60-day notice to over 50 employees that they would be laid off. The 60-day notice was
provided consistent with the WARN Act. Although the 60 days ran to November 25, 2024, USM
dismissed the laid-off employees from needing to report to the Rowley plant effective November
8, 2024.

USM’s headcount at the Rowley plant is currently 18 persons. Since the Rowley plant has
dropped below 25 persons, USM is suspending its status as a non-transient, non-community water
system. Effective November 8, 2024, USM suspended its monthly sampling/analysis for bacterial
contamination and logging daily chlorine residuals. USM will submit a water system chlorination
residual report for the fourth quarter of 2024 from October 1 through November 8, 2024.

USM will contact the Division of Drinking Water if and when the status of the Rowley plant
headcount increases above 25 persons and resumes its operation of a non-transient, non-
community water system.

Contact me if there are any questions.

Sincerely,
Rob J Hartman, P.G.
Environmental Manager
US Magnesium LLC
238 North 2200 West - Salt Lake City, UT 84116
M: 208.241.8216