DERR-2024-004678

Sent via electronic mail
January 8, 2024
Michael A. Zody
Parsons Behle & Latimer
201 South Main Street, Suite 1800
Salt Lake City, Utah 84111
[e-mail]

Jeffrey Mensinger
Environmental Manager
US Magnesium, LLC
238 North 2200 West
Salt Lake City, Utah 84116
[e-mail]

Re: Conditional Partial Assignment and Grant of Right

Dear Mr. Zody and Mr. Mensinger:

This responds to US Magnesium LLC’s (USM’s) correspondence to the U.S. Environmental Protection
Agency, of November 1, 2023, which, in part, provided a USM-executed version of the Conditional
Partial Assignment and Grant of Rights (conditional assignment), pursuant to the Consent Decree, Case
No. 2:01CV0040B (CD).

As stated in Appendix 4(A) of the CD, “[t]he closure system for the RWP present in this plan is
highlighted by the salt cap…” and “…will create a cap over sediments in the RWP through deposition of
salts…precipitated in place by evaporation of a brine feedstock obtained from the US Mag solar
evaporation ponds.” The CD requires, within 60 days of the Effective Date of the CD, that USM execute
the Conditional Partial Assignment and Grant of Right (Appendix G of Appendix 4(A)) as “[i]n an Event
of Default, it is the intent of the Parties to ensure that USEPA will have access to the necessary
resources to implement the Salt Cap Closure Plan and any subsequent revisions.”

Although USM has now submitted a USM-executed conditional assignment, correspondence from the
State of Utah (State) to both EPA and USM, of August 23, 2023, makes clear that the conditional
assignment – as currently drafted – would not adequately serve to ensure EPA has necessary resources
to implement the Salt Cap Closure Plan in an Event of Default, as intended and required by the CD.

2

The State noted that the conditional assignment would not “relieve either party of its obligation to
obtain the necessary approvals to either assign USM’s mineral lease or to begin reclamation of the site,
pursuant to a plan approved by FFSL,” and refused to be a signatory on the conditional assignment.

As long as both ready access to necessary resources and ability to implement the Salt Cap Closure Plan,
in an Event of Default, remains in doubt, EPA will maintain concerns as to whether the Salt Cap Closure
and Post-Closure Plan is protective of human health or the environment, as referenced in Paragraph
16(a)(2) of the CD.

EPA recognizes that USM has already adopted some revisions to the conditional assignment based on
previous engagement with EPA and the State. However, to date, these efforts have not yet been
successful in leading to an effective and implementable conditional assignment, as required by the CD,
or, further, in providing for EPA’s ability to implement the Salt Cap Closure Plan in an Event of Default.

EPA requests that USM continue its efforts to ensure the Salt Cap Closure Plan can be implemented by
EPA (through an effective, implementable conditional assignment, or otherwise), in case of an Event of
Default, to both comply with the requirements of the CD and ensure that the Salt Cap Closure Plan is
protective of human health and the environment.

Sincerely,

Max Greenblum
Senior Assistant Regional Counsel

Cc: Annette Maxwell, EPA
Kimberlee McEwan, Utah AG’s Office
Wes Sandlin, UDEQ
Dan Hall, UDEQ
Paige Walton, UDEQ
Emma Whitaker, Utah AG’s Office
Ben Stireman, Utah FFSL