Why It's Needed

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Why It's Needed

Why clean up the Holden Mine?

The principal environmental problems created by mining at Holden are:

  • Snowmelt and rainwater mix with metals to create acid mine drainage from the mine portal, and acid rock drainage from the tailings and waste rock piles
  • Acid rock drainage affects groundwater and surface water quality. This includes the water in Railroad Creek, which eventually flows into Lake Chelan
  • While creek water is safe for human consumption downstream of Holden Village, it contains concentrations of hazardous substances that exceed water quality standards for aquatic life
  • Slopes of tailings piles are too steep to withstand a large earthquake
  • Soils around the mine area contain elevated concentrations of naturally occurring metals

What does the cleanup entail?

All historic mining materials will be buried and capped in place. The one exception is a very small quantity of copper concentrate, which will removed and disposed of at a remote disposal site. The following actions will be taken to ensure an environmentally responsible cleanup of the Holden Mine site:

  • Remove the dilapidated mill building and relocate the nearby Holden Village museum to a site in the Village
  • Reshape and cover the tailings and waste rock piles with soil to restore vegetation. There are eight million tons of tailings and waste rock in three piles covering 90 acres
  • Consolidate contaminated soils with tailings and cover with soil to restore vegetation
  • Relocate sections of fresh-water creeks around contaminated areas
  • Install a below-ground barrier wall to collect contaminated water
  • Build and operate a water-treatment system
  • Use locally quarried rock and soil for erosion protection and capping the tailings and waste rock
  • Build improvements to support project operation, including:
    – Quarry to provide rock
    – Safety improvements on local roads
    – Temporary staging areas for equipment and supplies at Lucerne and Chelan
    – Barge ramp improvements at Lucerne and Chelan to allow movement of
       equipment and supplies up and down Lake Chelan

[remediation plan map and photos]
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