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a <br /> Figure 37: Photograph of Poverty Gulch from south of the Lillie mine,taken by Julia Skolas sometime between <br /> 1907 and 1915(www.mtgothictimes.com). The Lillie mine is in the foreground,followed by the Abe Lincoln, <br /> Chicago Tunnel,and C.O.D.mines. The approximate location of the PGMW 1 monitoring wells is indicated with <br /> a blue star,and PGMW 2 with a red star. <br /> The low pH measured in the shallow monitoring well (PGMW 1 B-55) probably results from oxidation of <br /> sulfide minerals (pH in this well has varied between 3.41 and 4.36, with a geometric mean of 3.7). The <br /> concentration of manganese in the shallow well is twice that in the deep well, and zinc concentration is <br /> almost four times higher in the shallow well than in the deep well. Sulfate concentration in the deep well <br /> is almost twice that in the shallow well. It is likely that manganese and zinc are being attenuated by the <br /> soil as water infiltrates to greater depths. Sulfate is a somewhat conservative solute, and the relatively <br /> low concentrations present in these two wells are unlikely to be attenuated. <br /> It is hypothesized that the elevated constituents in water sampled from the Poverty Gulch monitoring <br /> wells result from leaching of soluble species from the waste rock that was dumped in Poverty Gulch <br /> during historic mining. The fact that these monitoring wells have only contained sufficient water to allow <br /> them to be sampled between March 2000 and July 2001 suggests that there is very little recharge to <br /> Poverty Gulch. Even though much of the historic waste rock has been removed for processing, the <br /> chemical load in the soil will take a long time to be removed by recharge and migration down-gradient. <br /> 6.5 Wilson Creek <br /> The data from the Wilson Creek monitoring wells indicate that groundwater has not suffered impacts from <br /> historic or current mining and processing activities. Although Lindgren and Ransome (1906) show a <br /> number of small shafts and adits in the Bateman Creek drainage, there was very little production. <br /> Furthermore, as shown in Figure 38 (the location of the monitoring wells on the 1951 USGS 1:24000 <br /> topography), a natural divide separates the Bateman Creek catchment from the Arequa Gulch catchment. <br /> This divide has served to segregate the impacted groundwater in Arequa Gulch from Bateman Creek. <br />