Editor:
Regarding seepage rates from proposed tailings pond at Fish Lake; Nov. 8, 2013, Tribune.
Taseko claims the seepage estimates done by Natural Resources Canada for the Environmental Assessment process calls the panel’s findings into question.
I attended the hearing on tailings pond seepage and my notes indicate;
1.) Taseko and their consultants met face to face with Natural Resources Canada before the hearings began to address differing opinions on how to model the seepage losses from the 12 km squared tailings pond.
Knight Piesold, the consultant with the new information, attended the hearing.
2.) Taseko’s model suggested 70 liters/second of seepage would occur with 55 liters/second seeping through the tailings embankments and 15 liters/second seeping out the bottom of the tailings pond.
The evidence presented suggested that embankment seepage is relatively easy to collect. Seepage through the “foundation” or the bottom of the pond is very difficult to manage.
3.) Dr. Smith, the independent expert retained by the panel, stated “… foundation seepage estimates from 20 - 100 l/s is reasonable” (CEAA Document 751, Exhibit 22, p.18).
4.) The modelling work done by Natural Resources Canada suggested 100 liters/second of foundation seepage would occur.
I am not an expert but Taseko’s claim that errors around estimating seepage rates somehow draws the panel findings into question does not hold water.
Rodger Hamilton
Williams Lake