Ground Guardian​s LLC.

Remediation Design

Remedial Action Objectives

Remedial action objectives are goals created to assist in developing remediation alternatives. Objectives determined for the site will be used to develop and evaluate the remedial action alternatives. The objectives made for the Dragon Mine are as follows:

  1. Limit contaminated soil from tailings/hotspots migrating into the wash
  2. Mitigate human health risk by reducing lead and arsenic concentrations in DU-3, DU-4, and in hotspot areas to below nonresidential soil remediation levels or to background levels
  3. Reduce risk to wildlife from contaminant exposure in DU-4 and hotspot areas

Alternative Selection

Four alternatives were created to clean up the Dragon Mine and are listed below.

  1. Excavate hotspots, DU-3, and Du-4 to onsite repository
  2. Excavate hotspots to onsite repository; excavate/soil wash/replace DU-4; in-situ solidification of DU-3
  3. Excavate hotspots to DU-3 and solidify; excavate /soil wash/replace DU-4
  4. Excavate hotspots to DU-3 and cap; excavate/soil wash/replace DU-4

The alternatives were scored in 3 categories: effectiveness, implementability, and cost. Categories were scored on a scale of --/-/+/++, with -- being the worst and ++ being the best. Below is the decision matrix used to score the alternatives. Alternative 4 was determined to be the best alternative to remediate the site.

Option # Remedial Action Effectiveness Implementability Cost Total
1 Excavate HS, DU-3, & DU-4 to on site repository ++ + - ++
2 Excavate HS to onsite repository; excavate/soil wash/replace DU-4; in-situ solidification of DU-3 + -- -- ---
3 Excavate HS to DU-3 and solidify; excavate/soil wash/replace DU-4 + - + +
4 Excavate HS to DU-3 and cap; excavate/soil wash/replace DU-4 + + ++ ++++

Remediation Design

View Map

Implementation Cost

View Document