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Page 9 <br />May 5, 2009 <br />climatic conditions. Therefore, current interpretations should not be considered rigorous. Several <br />basic conclusions can be made as a result of the Lumsden Canyon reconnaissance as follows: <br />1. Surface-water flow in Lumsden Canyon is ephemeral. Base flow is locally controlled by <br />runoff from DP and PR Springs and bedrock, which commonly forms streambed and <br />several large pour offs. <br />2. The alluvium that makes up the streambed in places forms a relatively thin and <br />discontinuous aquifer. Mineralized rock, likely eroded from upgradient mine dumps, is <br />present through out the canyon within the stream alluvium. Consolidated bedrock restricts <br />downward flow of groundwater in the alluvium and with enough runoff or bedrock <br />recharge, the alluvium will fully saturate and result in surface flow. <br />3. The occurrence of persistent flow in the upper north fork Lumsden Canyon is a result of DP <br />Spring runoff. This water eventually infiltrates into the streambed, possibly recharging the <br />Entrada Formation in places. <br />4. PR Spring runoff also contributes flow to the north fork of Lumsden Canyon. This water <br />enters the north fork of Lumsden Canyon and also infiltrates into the streambed. <br />5. The main stem of Lumsden Canyon did not exhibit base flow. Bedrock and large fall areas <br />were present with no occurrence of surface water. <br />6. Two downstream reaches of Lumsden Canyon exhibited short sections of surface-water <br />flow as a result of bedrock channel or alluvium relief changes. It is also possible that <br />bedrock contributed water to the streambed alluvium in these areas. <br />7. The Lumsden Canyon Mouth sample site, as discussed in the September 2008 report, is not <br />interpreted as a "spring" as implied by the BLM samples collected in 1993 and the EFR <br />samples collected in 2007. This water is interpreted to be subsurface streambed water that <br />is exposed in the streambed due to bedrock impermeability or abrupt changes in elevation <br />of the streambed itself. This is common in and and semi-arid environments. <br />8. The hydraulic connection of upper Lumsden Canyon surface water with the lower Lumsden <br />Canyon surface water at the Lumsden Canyon Mouth sampling site could not be confirmed. <br />If upper and lower canyon streambed water is hydraulically connected, the flow path <br />involves over 3,000 ft of travel through stream alluvium and fractured bedrock. Surface <br />observations showed that at several locations where the streambed was bedrock, no flow <br />was present. Due to broad alluvial deposits in the lower canyon, it is not possible to <br />determine if there has been a significant loss of discharge from the upper to lower canyon, <br />i.e. subflow may be concealing a component of the total flow at the lower canyon locations. <br />Salt Wash Member Horizon <br />Surface reconnaissance revealed limited evidence that the Salt Wash Member (ore-bearing sandstone) <br />historically mined in the area is a major groundwater-bearing unit. With the exception of PR Spring, no <br />natural springs or seepage (some seepage was noted in the Dutchman Mine in June 2008) or discharge <br />from mine portals was observed from the stratigraphic horizon that included the ore-bearing, upper Salt <br />Wash Member sandstone. Groundwater that does occur within the Salt Wash Member is likely partially <br />lost through evapotranspiration near outcrop exposures. Flows observed in Lumsden Creek do not <br />indicate that the Salt Wash Member contributes discharge to the stream. A more thorough evaluation of <br />groundwater conditions can be made once access to the Packrat Mine is possible. <br />Weans=709.doc