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Industrial Minerals

Complex environmental cleanup restores valuable intertidal habitat at former mine site


more habitat created than expected

35,000+ native plants

in new habitat area

255,000 tons

of remedial excavation material removed


  • The Port of Tacoma, Washington, had to remediate and restore the extremely contaminated site of a former gravel mine and landfill. Investigations revealed that contaminants had entered the underlying groundwater and threatened to harm aquatic life in nearby Hylebos Creek.
  • The project presented unusual complexities because it paired a large cleanup with extensive habitat restoration. Also, debris filled the site, which sat at the base of a potentially unstable hill. The geotechnical and environmental design for the site also had to fulfill mitigation obligations from five different sources.
  • Haley & Aldrich brought a suite of services — geotechnical, environmental, and field-engineering expertise, along with construction oversight — and worked with multiple stakeholders to balance remediation requirements, soil removal costs, habitat mitigation, and recontamination risk (to minimize potential future cleanup).
  • The restored site now provides essential habitat for salmon and other wildlife and is open to the public.

For more information, contact:

Headshot of male, Gary Horvitz

Gary Horvitz

Principal Consultant

Mark Dagel

Program Manager