Dendritic Creek Debris-Flow Risk Reduction

CLIENT: Galore Creek Mining Corporation

LOCATION: Northern British Columbia, Canada

Galore Creek Mining Corporation (GCMC) is carrying out feasibility studies for the development of their Galore Creek Mine.  In the current development plan, water from Dendritic Creek will be intercepted and diverted away from and around a proposed open pit.  This current project refines preliminary debris flow volume estimates that were determined during an initial geohazards review of all components of the proposed Galore Creek Mine.  BGC Engineering Inc. (BGC) identified that debris flows along Dendritic Creek had the potential to impact the water diversion intake.  The potential debris flow volumes within the Dendritic Creek drainage system were estimated by modifying an existing debris flow sediment budget approach based on site specific observations and mapping.  In addition, BGC presented a conceptual assessment of potential debris-flow mitigation measures.

Four potential debris-flow risk reduction measures were studied to protect a potential diversion intake structure.  These options included the use of debris catchments, flexible debris-flow nets, earthworks barriers, and combinations of earthwork, concrete and steel grids in barriers.  The risk reduction measures were evaluated in function of an assumed design event, access for construction and maintenance based on site topography, environmental constraints and potential cost.  Flexible debris nets along with smaller fixed barriers, or large fixed barriers at the bottom of the channel alone, appear to be the most cost effective options to reduce risk to the water diversion structures.