Facility Site ID: 2251399 Cleanup Site ID: 4550

Site Description

Monte Cristo Mining Area - Circa 1912
Monte Cristo Mining Area - Circa 1912
The Monte Cristo Mining Area (MCMA) site is in the Cascade Mountains. It is part of the Mt. Baker-Snoqualmie National Forest in Snohomish County, Washington, near the Henry M. Jackson (HMJ) Wilderness Area. The Monte Cristo Mining District and the surrounding area have a rich mining history. Monte Cristo Mine peak production was in 1897.

Most ore production came from eight mines: Mystery, New Discovery, Pride of the Mountains, Pride of the Woods, Golden Cord, Comet, Justice, and Rainy Mines. The District processed mined ore for delivery to the Everett Smelter. By 1894, it could process up to 300 tons of ore per day. The Monte Cristo Mining District produced mainly gold, silver, copper, lead, and zinc.

The American Smelting and Refining Company (ASARCO) bought the mining operations in 1903. In 2009, Ecology and the United States Department of Agriculture Forest Service (USFS) received ASARCO bankruptcy settlement funds to clean-up hazardous materials and contamination from historic mining activities.

Property ownership in the area is complex. As a result, the United States and the State of Washington divided the settlement funds equally to pay for cleanup. The USFS conducted the removal action under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and is also known as Superfund. Ecology will continue cleanup of private landholdings under Model Toxics Control Act (MTCA) authority.

Non-time critical Removal Action (RA) activities:

The USFS used their authority to determine how much waste rock be removed and contained in the repository. After many years of planning and preparations, the USFS began the removal action in April 2015. The repository was grubbed, cleared, and logged in late April and early May 2015. Approximately 2.5 acres were cleared for construction of the repository; the actual repository covers approximately 1.15 acres.

After the construction of the repository was completed, approximately 8,067 bank cubic yards (bcy) of mine tailings were excavated from the former mine Concentrator area, 12 bcy of which was designated Dangerous Waste.

The following is a list of approximate bcy and pounds of waste rock excavated from other areas:

    •  1,099 bcy of waste rock was excavated and removed from the Ore Collector are

    •  955 bcy of waste rock was excavated and removed from the Comet Terminal and Haulage Ways

    •  213 bcy of waste rock was excavated and removed from the Assay Shack area

    •  2,148 bcy of waste rock was excavated and removed from the Rainy Mine area

    •  Pride of the Woods waste rock pile excavation and removal required transport via heavy lift helicopter of equipment, fuel, materials and supplies to the HMJ Wilderness Area. the total weight of waste rock removed from the HMJ Wilderness Area was approximately 6, 415,000 pounds.

    •  Mine adit diversion activities were completed at Mystery Mine #3 and Justice Mine

All disturbed areas at the MCMA were recontoured and revegetated during the 2016 and 2017 field seasons.

Complete details regarding the Removal Action are located at this link: http://www.fs.usda.gov/goto/mbs/CERCLA.

Ongoing Activities and MCMA:

Long-term monitoring by the USFS continues at the Site. In 2019, activities for long-term monitoring included:

    •  Surface water sampling to evaluate levels of arsenic in the South Fork Sauk River

    •  Inspection of the mine drainage diversions

    •  Groundwater monitoring at the repository

    •  Inspection of slope stability at the repository

    •  Continued revegetation of disturbed areas, as needed

Current Status

MCMA - Mine Opening - around 2014
MCMA - Mine Opening - around 2014
USFS contractors were unable to visit the MCMA in 2020 due to the COVID-19 pandemic. Long-term monitoring will begin again during the 2021 field season. Ecology continues to work with private landowners to cleanup to MTCA human and ecological health standards. Institutional controls (signage) are expected to be installed during the 2021 field season.

Public Involvement Opportunities

Ecology wants to keep you involved!  You have the opportunity to review and comment on key documents during the cleanup process. 
Public Information 4
Document Title Document Date Document Type
MCMA 2015 Interim Action and SEPA Responsiveness Summary 7/16/2015 Responsiveness Summary
MCMA Interim Action Plan Fact Sheet 5/18/2015 Fact Sheet\Public Notices
MCMA Planned RI/FS and SEPA fact sheet 8/16/2011 Fact Sheet\Public Notices
MCMA Public Participation Plan 8/16/2011 Public Participation Plan
State Environmental Policy Act 4
Document Title Document Date Document Type
MCMA SEPA Determination of Non-Significance 2015 5/13/2015 SEPA Documents
MCMA SEPA Checklist 2015 5/12/2015 SEPA Documents
MCMA SEPA Determination of Non-Significance 8/15/2011 SEPA Documents
MCMA SEPA checklist 8/15/2011 SEPA Documents
Technical Reports 11
Document Title Document Date Document Type
Monte Cristo Mining Area - ECY Plans to Improve Water Quality at MCMA 2/23/2023 Site Specific Administrative Document - other (Administrative correspondence)
Non-Time Critical Removal Action Report 12/8/2016 Remedial Action Report
MCMA Terrestrial Investigation Summary Report 8/31/2015 Terrestrial Ecological Evaluation
MCMA Final Interim Action Plan for 2015 7/1/2015 Interim Action Documents
MCMA Aquatic Baseline Monitoring 3/31/2015 Site Specific Technical Document - other
MCMA Draft Interim Action Plan for 2015 4/1/2014 Interim Action Documents
MCMA RI Phase 3 Characterization of Aquatic Sampling Reaches Recon Report 3/29/2013 Remedial Investigation Report
MCMA RI Phase 2 Summary Report 5/31/2012 Remedial Investigation Report
MCMA SAP & QAPP 8/10/2011 Sampling and Analysis Plan
MCMA Phase I Spatial Analysis Summary rpt 4/20/2011 Remedial Action Report
MCMA RI Phase I Data Report 4/5/2011 Remedial Investigation Report
There may be more documents related to this site. To obtain documents not available electronically, you will need to make a public records request.

Places to see print documents

  • Central Regional Office
    1250 W Alder St
    Union Gap, 98903-0009
    Please schedule an appointment to view print documents at this location.
  • Darrington Public Library
    1005 Cascade St
    Darrington, 98241
    This location may only have print documents available during open comment periods.

Contaminants 2

Contaminant Type
Surface Water
Metals - Metals Priority Pollutants C S C S C
Metals - Metals - Other C S C S C
Confirmed Above Cleanup Levels
Below Cleanup Levels
This contaminant list was based on our best information at the time it was entered. It may not reflect current conditions at the site.