Oceanography / Limnology
Numerical Modeling
Visualization and Animation
Specialized Sampling Tools
Acid Rock Drainage
Database/Software Development

The most effective and direct manner in which to assess the chemical stability of contaminated sediments and submerged tailings deposits is through the collection and analysis of porewaters. Porewater chemistry is the most sensitive indicator of metal remobilization, and porewaters represents the vector for metal transport into surface waters.

Dialysis arrays (peepers) are a suitable method for obtaining high-resolution profiles of dissolved constituents in tailings and sediment porewaters. A peeper consists of a Plexiglas plate with rows of chambers machined down its length, which are filled with distilled deionized water (DDW). During deployment, the DDW contained within the peeper chambers is allowed to approach a diffusive equilibrium with the adjacent porewater. In this manner, the composition of the water trapped within the peeper cells is compositionally identical to the porewater matrix at the end of the deployment period.

Only with an understanding of the controls governing contaminant mobility can scientifically-defensible and cost-effective management plans be developed. By measuring the distribution of metals and ancillary parameters in porewater and across the sediment-water interface, such controls can be defined.

The specific objectives which can be addressed with peeper studies include the following:

  • To determine the magnitude and direction of contaminant transport across the tailings-water interface;
  • To quantify impacts to surface waters resulting from contaminant remobilization;
  • To determine the biogeochemical controls governing the mobility of mine-derived contaminants;
  • To develop water quality predictions during operations and closure; and
  • To aid in the development of closure and/or remediation planning.