Holden Mine


The Holden Mine Site is located in Chelan County in a remote area of the Cascade Mountain Range in the Wenatchee National Forest.  The property is adjacent to many important natural resources and encompasses Holden Village.  The Department of Ecology (Ecology) is working cooperatively with the USDA Forest Service (Forest Service) and the Environmental Protection Agency (EPA) towards Site cleanup.  The Forest Service is the lead agency for cleanup at this Site.  For more detailed Site information, visit the Forest Service Holden Mine Site webpage.
From 1937 to 1957, the Howe Sound Company conducted mining operations at the Holden Mine site.  Their mine and mill facilities produced primarily copper concentrate and lesser quantities of concentrate of zinc and gold.  The operation was stopped in 1957 when the profitability of copper mining declined.  Successors to Howe Sound include Alumet Corporation and, more recently, Intalco Aluminum Corporation (Intalco).  After the mining operation closed down, the mining interests were deeded to the Lutheran Bible Institute (currently known as Holden Village).  Since 1961 the former mining town site, Holden Village, has served as a non-profit Lutheran ministry and community under a special use permit with the Forest Service. Approximately 5,000 to 6,000 people visit the facility each year and 60 to 70 residents live at Holden Village year round.
Significant contamination has resulted from past mining activities and presents a risk to human health and the environment.  Toxic concentrations of metals and petroleum and acidic conditions are found in groundwater, surface water, sediments, and/or soil.  Sources of hazardous substances include soil that has been impacted by the past mine operations as well as spills from equipment maintenance.  In addition, acid mine drainage (in the form of mine portal drainage, seeps, and upwelling groundwater) contributes to the ongoing release of metals and acidity from the mine workings, waste rock piles, and tailings piles into surface water and groundwater at the Site.  During operation, about 57 miles of underground mine workings were developed.  About 8.5 million tons of tailings were placed in piles covering a 90 acre area along Railroad Creek.  Several piles of waste rock removed from the mine are located near the mine portals at various locations throughout the site.  The Site includes the 125 acre mining operation and village footprint, a 10 mile segment of Railroad Creek downstream of the mine, and an approximately 10 acre area of Lake Chelan sediments where Railroad Creek flows into the lake.
During the late 1980s and early 1990s, the Forest Service reduced erosion of the tailings piles by installing streambank protection, rerouting drainage, and covering the piles with gravel, which also reduced dust generation and facilitated initial revegetation.  This interim action improved site conditions; however, several potential threats to human health and the environment still exist.


Preparations for a final cleanup began in 2011 (see calendar).  The planned cleanup will be completed in a phased approach.  Major components of the cleanup include stabilizing and capping the tailings and waste rock as well as capturing and treating impacted mine portal drainage, groundwater, and seeps to stop the ongoing release of hazardous substances and prevent exposure to humans and the environment.


  • 1897: First mining claims located at Holden Mine
  • 1937 to 1957: Holden Mine operations
  • 1989-1991: Interim Actions
  • 1993: Alumet Corporation (Alumet) identified as a Potentially Responsible Party (Intalco Aluminum Corporation is the successor to Alumet)
  • 1996-1998: Negotiated Administrative Order on Consent (AOC) for Remedial Investigation/Feasibility Study (RI/FS) with Alumet
  • 1997-2002: Ongoing RI and FS work and reporting
  • 2002: Draft RI (1999) accepted by the Agencies on the condition that additional field work be completed during FS
  • 2002-2010: Continued investigation and feasibility study activities
  • 2010: Proposed Plan and Final Amended Supplemental FS issued
  • 2011-2012 Goal:
    • Record of Decision (ROD)
    • Consent Decree (CD)
    • Early Actions (ex. roads, bridges, staging areas, hydraulic bulkhead construction, timbering, quarry and borrow operations)
  • 2013-2014 Goal: Cleanup Action Plan (CAP) implementation (Phase I)
  • 2015-2019 Goal: Ongoing monitoring and design of Phase II
  • 2020 Goal: CAP implementation (Phase II)


Remedial Investigation

The Draft Final Remedial Investigation was submitted on July 28, 1999.  On February 8, 2002, the Draft Final Remedial Investigation was accepted as final by the Agencies.  Acceptance was based on the expectation that as part of the Feasibility Study, additional information would be subsequently developed by Intalco to resolve a considerable number of comments on the Draft Remedial Investigation.

Feasibility Study

The Agencies are not requiring Intalco to resubmit the feasibility study.  Rather, the Agencies accept a final Feasibility Study that consists of:

Proposed Plan

Holden Mine Proposed Plan

2011 Early Works Documents

Holden Mine 2011 Early Works Implementation Plan Agency Comments on 2011 Early Works

Record of Decision

Holden Mine Record of Decision



Map showing site location as Chelan County, WA SITE INFORMATION


View Electronic Documents

Cleanup Site Details Report

Facility Site ID: # 338

Cleanup Site ID: 4414

Holden, Chelan County

Status: Cleanup Started   Get definitions of Status terminology

Document Repositories:

Central Regional Office
1250 W Alder St
Union Gap, 98903-0009

Okanogan-Wenatchee National Forest Headquarters
215 Melody Ln
Wenatchee, 98801