South Bay: implications of the draining of mill pond / review prepared for M. Kalin, Boojum Research Ltd, Toronto

Abstract

Mill Pond is located to the east of a topographic divide on the mill site. It receives surface runoff and shallow groundwater discharge. At the northeastern/ eastern part a small dam has been constructed. The surface elevation of the water level in Mill Pond is such, that it is higher than the elevation of the seeps WHS and WHSS. Mill Pond could, therefore, be a source of water contributing to these seeps. Unfortunately, there is neither shallow stratigraphic information nor information with respect to the configuration of the bedrock surface between Mill Pond and the seeps to indicate a potential path for the shallow groundwater. Furthermore, it would be next to impossible to obtain this information, because of the effect of the decommissioning and subsequent landscaping of the mill site. The only way to determine a possible inter-relationship between the seeps and Mill Pond is to drain the pond temporarily and observe the effect of the draining. The experiment was started on June 3, 1998, after a siphon, which drains towards Boomerang Lake, had been installed in the Mill Pond. Daily and on occasion multiple daily measurements were taken of the flow at various locations on the mine site, the water levels in piezometers, shaft, PRC, etc. Furthermore precipitation was recorded, as well as basic chemical parameters were measured and water samples were collected for future analysis.