DSHW-2025-002653

Statement of Basis
for the US Magnesium LLC Landfill Class IIIb Permit

1. INTRODUCTION

This Statement of Basis provides the rationale of the Director of the Division of Waste Management and
Radiation Control (DWMRC) for issuing a permit to US Magnesium LLC for a Class IIIb Landfill. The
Director’s staff conducted this evaluation to ensure compliance with the applicable solid waste rules. Beatriz
Ávila wrote this Statement of Basis.

2. FACILITY BACKGROUND

a. Facility Location and History

The landfill is in the West ½ of Section 10, and the West ½ of the East ½ of Section 10, Township 2
North, Range 8 West, Salt Lake Base and Meridian, Tooele County, Utah; Lat. 40º 54’ 49.5" North,
Long. 112º 44' 1.5" West.

12819 N Rowley Rd. Skull Valley, UT

b. Regulatory History

The landfill was initially developed in 1972 and has been receiving regular waste deposits from
magnesium mining operations since that time. The companies that have owned and operated the
landfill have been cooperative with the various agencies that regulated landfill operations, routinely
filing necessary documents, including variance requests for alternative landfill cover since at least
1988 (DSHW-1988-004101); an initial permit application in 2000 that was incomplete (DSHW-
2000-007382); annual reporting each year as required since 2002 (DSHW-2003-014028); and in
recent years, US Magnesium LLC submitted a new permit application as discussed below.
Inspections of the facility have been conducted over the years by the Tooele County Health
Department until at least 1991, and in 1992, inspections by the Utah Department of Environmental
Quality began.

The facility is used for disposal of nonhazardous industrial solid waste and asbestos waste generated
by US Magnesium LLC into a Class IIIb landfill cell. This is the first permit to be issued for this
facility.

3. EVALUATION OF THE PERMIT APPLICATION

a. The Division determined the Permit Application (DSHW-2021-025123) for the US Magnesium
Class IIIb Landfill was complete on January 26, 2022 (DSHW-2021-024922). On June 23, 2023,
January 18, 2023, April 10, 2023, February 12, 2024, and October 17, 2024, US Magnesium LLC
provided additional information (DSHW-2023-004056, DSHW-2023-000396, DSHW-2024-005126,
DSHW-2024-008768, respectively) in response to requests for information from Division
representatives, and this information has been included in Attachments #1, #2, #3 and #4 of the
Permit.

b. US Magnesium LLC requested an exemption from the floodplain requirements of Utah Admin. Code
R315-302-1(2)(c)(ii), providing a justification for the exemption in Section 3.4 of the Permit
Application. The Director approves the exemption because the facility is expected to have a
negligible impact on the flow and storage capacity of floodwaters. If floodwater causes washout of
solid waste from the landfill cell, including outside of the facility or property boundaries,
US Magnesium LLC shall remediate any contamination of the groundwater, surface water, or soil
that results from the management of solid waste which presents a threat to human health or the
environment through appropriate corrective action in accordance with Utah Admin. Code R315-301-
6 and by approval of the Director.

c. US Magnesium LLC requested an exemption from Utah Admin. Code R315-302-1(2)(e)(i)(B),
which prohibits waste from being any closer than ten feet above the historical high level of
groundwater in landfill cells without a liner (Section 3.6 of the Permit Application). The Director
approves the exemption because disposal of waste below this level occurred before this standard was
established and all new loads will be disposed of approximately 20 to 40 feet higher than the
groundwater table. If contamination of the groundwater beneath the facility results from past,
present, or future management of solid waste which presents a threat to human health or the
environment, US Magnesium LLC shall remediate the threat through appropriate corrective action in
accordance with Utah Admin. Code R315-301-6 and by approval of the Director.

d. US Magnesium LLC requested the use of alternative daily cover as described in Sections 4.4, 4.5,
and 4.7 of the Permit Application (also see Attachment #2). Since at least 1988, US Magnesium has
historically received approval to use gypsum tailings as alternative cover of waste in the landfill cell,
with a stipulation that waste is also covered with six inches of soil at a minimum of once each
month. The Director approves continued use of gypsum tailings as alternative cover, with a
requirement to use six inches of soil for cover no less than once each month as found in the
conditions of Section III.E of the Permit.

4. JUSTIFICATION FOR ISSUING THE PERMIT

a. The Director’s staff has evaluated the permit application as required by Section 19-6-108 of the Solid
and Hazardous Waste Act and Utah Admin. Code R315-301 through 322. The information provided
in the permit application satisfies the requirements.

5. PUBLIC PARTICIPATION

a. As required by Utah Admin. Code R315-311-3, the Director provided an initial 30-day public
comment period [dates of comment period and any comments received will be added here].

6. DIRECTOR RESPONSE TO PUBLIC COMMENTS: [as needed]

Figure 1
Facility Location