Introduction

In the 1990’s, the Unsaturated Soils Group at the University of Saskatchewan, in conjunction with Placer Dome Canada, undertook a research program to study the moisture flow in layered waste rock piles. A near vertical section of an end-dumped waste rock pile was exposed at the Golden Sunlight Mine in Southwest Montana, USA. Figure 1 shows a photograph of the section, which clearly shows the highly stratified nature of the dumped material. Visual inspection of the layering revealed some oxidation in the fine-grained layers, but not in the coarse layers. This suggested that moisture infiltration must have migrated to the bottom of the pile via the fine-grained layers and not so much through the coarse layers.

A laboratory testing program was undertaken by Lori Newman as part of her M.Sc. research to investigate this phenomenon. A summary of her experiments and findings are published in a paper presented at the 1997 Canadian Geotechnical Conference in Ottawa (Newman et al., 1997).

This document describes how SEEP/W can be used to model the preferential flow Newman (1997) observed in her laboratory column tests.