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eii iiiiiiiiiiiu iii <br />INTERNAL MEMO <br />To: Sandy Brown 10 March 1999 <br />From: Jim Burnell <br />SUBJ: Bourg 1998 AHR Review <br />I have reviewed the Annual Hydrology Report from the Bourg Mine and find that the report is <br />acceptable. <br />Groundwater monitored at the mine site at two different locations -well 30C and well 338. Well 336 <br />serves as an upgradient well, sampling water that is just "entering" the mine site from upgradient in <br />Mann Draw. Well 30C samples this water as it passes off the mine site (or, more appropriately, from <br />beneath the mine site) which has been affected by water percolating through the spoils. <br />There are no strikingly high values of contituents analyzed. In general, there has been a consistent <br />pattern for groundwater chemistry to change between the wells, presumably representing the change in <br />chemistry as the spoils water is added between the two sites. <br />General trends are those that would be anticipated: <br />(]) Groundwater leaving the site has higher Na, Ca, Fe, Cl, sulfate and total dissolved solids (TDS) <br />than water entering the site. None of these constituents are greater than would be anticipated in bedrock <br />groundwater in the area and, although not much data exist, I think concentrations are probably not very <br />different from [Host upland alluvial groundwater in North Park. The TDS of water leaving the site is, <br />in fact, a great deal lower than is normally seen in groundwater affected by spoils discharge (around <br />1300 mg/1). <br />(2) Groundwater leaving the site generally displays a higher pH than water entering the site, although <br />values for both are effectively neutral regarding acid-base. <br />(3) Concentrations of components in the water entering the site vary considerably, probably as a <br />function of rainfall. Hence, any clear, well-defined "trends" are difficult to extract from the data. <br />