9.a Tiller Mine Groundwater Elevations - All Wells and ThresholdU:\5028SCA01_Scandia Tiller Manning\Hydrogeo\Groundwater Elevations - All WellsGW EL All Wells ThresholdLRE Water860870880890900910920930Elevation (ft amsl)DateGROUNDWATER ELEVATIONS AND EXCAVATION THRESHOLD5/2008 - 10/31/2019TILLER MINESCANDIA, MINNESOTAPZ-4PZ-5MW-1MW-2 (aband. June 2011)PZ-6Prod WellPZ-3Pond50 FeetExcavation depth cannot be greater than 50 ft below the lowest watertable elevation (915.87 ft amsl) measured in PZ‐4 in 2008, which isthe baseline established in the groundwater protection plan. Thisthreshold elevation was calculated at 865.87 ft amsl based on theOctober 30, 2008 PZ‐4 water level measurement.865.87 feet amsl