080121-08MN006-Sabina Hackett River Project Proposal ... - NIRB

Description of the Existing EnvironmentSeasonal VariationThere were significant differences in lake water quality between the winter and summer seasons,and also among months within the summer season. pH and sulphate values changedsignificantly with time at a few lakes, likely as a result of mineralized area seepage. Most metalsalso varied significantly with time at many of the lakes; Al, As, Cd, Cu, Pb, Ni, and Znconcentrations all varied substantially with time. Some lakes exhibited slightly higher metalconcentrations during the winter, while others underwent drastic changes in metal concentrationsduring the open water season, as a result of changing hydrological conditions and seepage.Spatial VariationLake water quality varied significantly with spatial/hydrological distance from the main minablemineralized areas, Main Zone (Camp Lake), Boot Lake, and East Cleaver. These three resourceslie within three separate watersheds; Camp Basin, Boot Basin, and Cleaver Basin, respectively.In general, lakes in the Camp Basin had the lowest average pH values, and the highest averageAl values. Camp Lake overlies the mineral resource of the Main Zone, and has also hostedwinter exploration drilling. As expected, the lake has relatively high concentrations of Al, Cd,Cu, Pb, Ni, and Zn.The Boot Basin lakes in general had lower metal concentrations compared to lakes in the otherbasins, with the exception of high Ni concentrations in Boot Lake.Cleaver Lake, located due west of the East Cleaver Zone mineralized area in the Cleaver Basin,had very high concentrations of Cd, Cu, Pb, Ni, and Zn. Metal concentrations measured in thislake (and in downstream Anne Lake) were the highest recorded in the area, with zincconcentrations reaching nearly 4.0 mg/L. Cd concentrations were also extremely high, averagingabout 0.025 mg/L in 2007.Annual VariationThere were differences in average annual concentrations of some parameters for some lakes,while other parameters (e.g., Ni in the Camp Basin lakes) remained very stable over the period ofrecord. No overall trends were evident, with the exception of apparently high values in 2006 formany metals and nutrients. However, this is an artefact of too high of detection limits being usedfor the 2006 study.The 2007 data set encompasses much more natural variability in the lakes than the historical datafrom 2004 to 2006. In addition, lake samples collected in 2007 were obtained from a boat atvarious depths within a lake, as compared to shoreline grab samples from the historical studies.Hence, some of the annual variations observed may have been due to these factors.6.1.10.4 Stream Water QualityStream water quality was measured three times during the open-water season in 2007: June(freshet), August (low-flow conditions), and September (Rescan 2008a). Historical data areavailable from some streams for the following periods: August 2004, July 2005, July 2006 (GLL2004, 2005, 2006).January 2008 Hackett River Project – Project Proposal Sabina Silver CorporationReport Version B.1 6–19 Rescan Environmental Services Ltd. (Proj. #833-2)