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Water was found to mound several feet along the upstream (southern and western) edges of the west cell <br />after installation of the slurry wall. Depending on the hydraulic connection between the Brighton Ditch <br />and groundwater table, the ditch could potentially gain over parts of the reach nearest the west cell <br />slurry wall. <br />Simulations run without the presence of the Challenger Pit and Baseline Mine showed that groundwater <br />impacts from only the Tucson South cells was much less compared to the impact of all proposed mines. <br />Specifically, the simulations show that for the isolated Tucson South scenarios, water tends to mound <br />instead of being drawn down. Well impacts in these isolated scenarios are predicted to be minimal. <br />Due to the magnitude and extent of drawdown resulting from the reduction of groundwater flow to the <br />greenhouses, the greenhouse wells are likely to be impacted, even to the extent of going dry. We <br />recommend that alternative methods of providing the greenhouse owners with water be considered. <br />These methods could include bedrock wells or water piped in from locations outside of the area of <br />influence. <br />The property inside the east cell will be completely enclosed by slurry walls, separating it from the <br />alluvial aquifer. Water levels during mining will likely be close to bedrock as the inside of the east cell <br />is dewatered. Water levels after mining completion will depend mostly upon water levels in the east cell <br />reservoir. There is currently one well on this property. <br />On the scale of this project, the alluvial and bedrock aquifers are separate hydrologic systems. Because <br />all mining, slurry wall, and dewatering activity will take place in the alluvium, impacts on bedrock <br />aquifer wells and the bedrock aquifer itself should be negligible. <br />5.0 LIMITATIONS <br />Groundwater modeling is a useful tool for determining the magnitude of impacts to the groundwater <br />system in an area. However, results are not absolute and local variances from simulated results are <br />likely to occur. This groundwater model is based on the aquifer parameters that we believe to be <br />reasonable given our current knowledge of the site. Should conditions be encountered that are <br />significantly different from those used in this analysis or should mining activities in the area be changed <br />significantly from those simulated, we should be contacted to evaluate the appropriateness of the <br />existing model. <br />- 11 - August 2004 <br />I:U919_019\TS GW Model\TS Report\Turson South_Rp~ DreR.doc <br />