Construct Interim Remedial Action (IRA) for the Nelson Tunnel Superfund Site

This is a pre-solicitation notice. This is not a solicitation and any offers received as a result of this pre-solicitation notice will not be accepted or evaluated. USACE Omaha District intends to issue Request for Proposal (RFP) solicitation W9128F27RA056 for the following action in November 2026 with the planned proposal due date in January 2027. ***PLEASE REFERENCE THE SITE VISIT INSTRUCTIONS IN THE ATTACHED DOCUMENT AND RESPOND NO LATER THAN THE DATE SHOWN.

Project Title: Construct Interim Remedial Action (IRA) for the Nelson Tunnel Superfund Site Project Location: One mile north of the town of Creede in Mineral County, Colorado NAICS Code: 237990 - Other Heavy and Civil Engineering Construction PSC Code: Y1LC - Construction of Tunnels and Subsurface Structures Set-Asides: This solicitation will be issued unrestricted; both small and large businesses are encouraged to participate.

Synopsis of Project: Construction Services for the Nelson Tunnel/Commodore Waste Rock Site (Nelson Tunnel Site or Site), the focus of the interim remedial action (IRA), consists of an abandoned underground hard rock mine and drainage tunnel with several shafts, crosscuts and drafts branching off the main tunnel. The remedial action objective of the RA is to reduce the likelihood of a large, uncontrolled release of mine-impacted water from mine pools impounded within the Nelson Tunnel. The selected alternative for the Nelson Tunnel Interim Record of Decision (IROD) is to construct a bypass adit that connects into Nelson Tunnel at a sufficient distance from the surface to allow for installation of a flow-through hydraulic bulkhead within Nelson Tunnel.

The IROD selected remedy is Alternative 4, Drive New Adit to Intersect Nelson Tunnel, Tunnel Rehabilitation, Install Bulkhead in Nelson Tunnel and Flow Control Structure in Commodore 5 level and include the following remedial components. 1. Installation of a new adit south of Nelson Tunnel, to bypass the Nelson Tunnel Portal Pool.

1. Rehabilitation of Nelson Tunnel from the bypass adit connection to the location where bulkhead construction is planned. 3.

Installation of a flow control bulkhead in Nelson Tunnel to protect against a sudden uncontrolled release through Nelson Tunnel.4. Installation of an accessible bulkhead flow control structure in the Commodore 5 level to protect against a sudden uncontrolled release through this level. Additional Information can be found at the following EPA website provided in the attachment.