09/30/2026
CITY OF ROSLYN
NOTICE OF PRELIMINARY SEPA ACTION
Roslyn No. 4 Mine – Cleanup Action
Project Name Roslyn No. 4 Mine – Cleanup Action
Site Address 205 E Dakota Avenue, Roslyn, Washington 98941
Kittitas County Parcel 456234
Site Area Approximately 30.4 acres
Cleanup Site ID 15545
Facility Site ID 66921
Applicant / Property Owner Forterra Roslyn LLC
Application Date July 20, 2026
Date Determined Complete August 17, 2026
Date of SEPA Notice September 17, 2026
The City of Roslyn is providing this notice concerning the State Environmental Policy Act (SEPA) environmental review of the proposed Roslyn No. 4 Mine Cleanup Action. This notice is intended to provide early public notice and an opportunity for comments concerning the City's preliminary SEPA action before the City makes its final SEPA threshold determination. It is not a final Determination of Nonsignificance (DNS), Mitigated Determination of Nonsignificance (MDNS), or Determination of Significance (DS).
PROPOSED ACTION
Forterra Roslyn LLC proposes a temporary environmental cleanup action at the former Roslyn No. 4 Mine site. The Cleanup Action would remove contaminated soil from six defined cleanup areas: the former vehicle maintenance area, former foundry, slag pile, former powerhouse, former power transformers, and a vegetated area. Excavation is proposed to approximately 1 to 3 feet below ground surface, with approximately 500 cubic yards of impacted material removed and transported to an appropriately permitted off-site landfill. Excavated areas would be backfilled with clean fill and topsoil, graded to match pre-construction contours, stabilized, seeded, and planted with native species. Wetland and associated buffer areas disturbed by the cleanup would be restored and monitored in accordance with the Wetland Disturbance Area Restoration Plan.
Additional Information on Project: https://cityofroslyn.sharepoint.com/:f:/g/buildingpermits/IgDcOuWljBdOTYZ2zTEwqvTNAcRQrquQzVqVC0ppJAZsQWU?e=I1Lofj
PRELIMINARY SEPA ACTION
A SEPA Environmental Checklist dated June 23, 2026 and revised August 31, 2026 was prepared for the project. The checklist states that cleanup activities are anticipated from Fall 2026 through Fall 2027, with construction duration estimated at less than eight weeks.
Preliminary SEPA action: The City expects to issue a an MDNS for this project.
This preliminary SEPA action is not a final threshold determination. The City will consider timely comments and any additional information received during the applicable preliminary-comment period before making the final SEPA determination required by RMC 18.40.015. The final threshold determination may be a DNS, MDNS, or DS, as applicable.
Once the City makes a threshold determination, RMC 18.40.015(F) provides that the City will issue a notice of decision for associated land use applications or permits. In accordance with RMC 18.40.015(F)(1) publication of notice of the determination will be in the City's newspaper of record.
OTHER CITY REVIEW / APPROVALS
The project materials identify the following City review items that may apply to the cleanup action:
Critical Areas Determination / Critical Areas Ordinance review under RMC Chapter 18.90.
Clearing and Grading Permit, if required by the City for the proposed excavation and site restoration.
SEPA environmental review and the applicable SEPA threshold determination.
The submitted JARPA identifies a Washington Department of Ecology Section 401 Water Quality Certification. JARPA also identifies SEPA as pending with the City of Roslyn. Federal Clean Water Act Section 404 authorization was evaluated in the project materials; the project record states that federal jurisdiction will be confirmed and that a Section 404 permit may be required if jurisdictional wetlands are affected. An archaeological monitoring permit is also identified in the JARPA materials.
ENVIRONMENTAL DOCUMENTS / STUDIES
SEPA Environmental Checklist, June 23, 2026.
Cleanup Action Plan, Roslyn No. 4 Mine, prepared by Maul Foster & Alongi, Inc., August 11, 2025.
Joint Aquatic Resources Permit Application (JARPA), signed July 17, 2026, including project plans and attachments.
Wetland Disturbance Area Restoration Plan, Haley & Aldrich, July 10, 2026.
Draft Aquatic Resources Report, Haley & Aldrich, July 2026, as referenced in the project materials.
Site Plan, Haley & Aldrich, June 2026.
City of Roslyn Pre-Application Conference Meeting Summary Notes, March 6, 2025.
EARLY PUBLIC COMMENT ON PRELIMINARY SEPA ACTION
The city is inviting written comments on the preliminary SEPA action. Comments should address environmental information, potential environmental impacts, mitigation, or other SEPA matters relevant to the proposed cleanup action.
Preliminary SEPA Comment Period: September 17, 2026 through October 16, 2026
Comment Submission: City of Roslyn, 201 S. 1st Street, Roslyn, WA 98941 (outside drop box available); or via email to [email protected]
The City will consider timely comments received during the applicable preliminary SEPA comment period in accordance with RMC 18.40.015 and applicable state SEPA requirements. This preliminary comment opportunity does not itself establish or replace any comment, notice, scoping, or appeal period that applies to a subsequent final SEPA determination.
PUBLIC REVIEW / INSPECTION
The SEPA Environmental Checklist and associated environmental documents are available for public review at the City of Roslyn administrative offices, 201 S. 1st Street, Roslyn, Washington 98941, and by contacting us via email to receive electronic copies at [email protected]
SEPA PROCEDURAL INFORMATION
RMC 18.40.015 states that a preliminary SEPA threshold determination, or preliminary SEPA action, does not substitute for or circumvent the process for making a final SEPA threshold determination or taking a final SEPA action.
RMC 18.40.015 states that preliminary SEPA determinations are intended to encourage early public comment on project applications.
RMC 18.40.015 requires a threshold determination within 90 days from the date an application is deemed complete for a proposal that is not categorically exempt. The section identifies DNS and DS as the threshold determinations and also authorizes an MDNS where appropriate.
RMC 18.40.015(F) provides that, whenever the City makes a threshold determination, it should seek to include public notice of the SEPA action with the notice of application or notice of decision for associated land use applications or permits. If no public notice is required for the associated permit or approval, RMC 18.40.015(F)(1) provides for newspaper publication of notice of the DNS or DS.
RMC 18.30.150(D) provides that appeals of SEPA threshold determinations or SEPA actions shall be combined with appeals of associated applications or permits.
CITY CONTACT
City of Roslyn
201 S. 1st Street
Roslyn, WA 98941
Michelle Geiger
Email: [email protected]; Phone (509) 304-8337
