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Probable Hydrologic Consrquertcrs - Chimnry Rock Mirtr <br />• where K is the hydraulic conductivity, dh is the vertical difference in ground water elevation <br />between two points, nr is the effective porosity, and dl is the distance between the two points <br />(Fetter, 1981). Assuming an effective porosity of 0.30, and determining the hydraulic <br />conductivity from the transmissiviry data of 1982 (approximately 225 ft/day), the distance and <br />height (gradient) of 0.25 ft/ft (Piteau and Associates, 1982) then: <br />v, _ (225 ft/day) (50 ft) / (0.30) (200 fr) <br />v, = 187.5 fr/day <br />This indicates that the velocity of ground water movement through the Fruitland Formation is <br />adequate for infiltration to have taken place since the time of pit backfilling. The pit in this area <br />was backfilled in 1985; therefore, degradation to the water quality or quantity in the area would <br />have apparently occurred prior to the present. <br />Since the alluvial aquifer and the stream are hydraulically connected, the effects observed in the <br />aquifer should be apparent in the stream. The effects that have been observed in the alluvium <br />and the stream would be represented by the data from the up and downgradient monitor points. <br />Data from surface monitoring stations S-1 and S-2, and wells W-7 and W-5 should therefore <br />represent the effects the activity from 1985 (the end of mining activities) until the end of the <br />• monitoring period. A summary of the data from these points only is included as Table 1. <br />Data from the wells W-7 (located upgradient) and W-5 (located downgradient) from the <br />September 1989 sampling event were compared to determine impacts to the shallow alluvial <br />aquifer. The comparison of these two results indicates the water quality actually improves in <br />the downgradient well. This data indicates that the alluvial aquifer has exhibited relatively little <br />impact, if any. <br />An exception is noted that the quality in the well A-1, located west of the former east pit area, <br />has shown elevated levels of TDS, conductivity, sodium, magnesium, manganese, iron, calcium, <br />and sulfate in December 1994. Compared to other wells in the area this well has traditionally <br />demonstrated elevated levels of these constituents. This well is continuing to be monitored as <br />part of the current monitoring program. Wells A-1, W-I and W-5 have had linear regression <br />analyses performed to attempt to predict future electroconductivity and total dissolved solids <br />levels in the water samples from the wells. These regressions are included as Appendix A. <br />A conservative estimate of salinity from backfilled spoils discharge loading on Stollsteimer Creek <br />was developed based on a recharge model. Average precipitation at the site is 13.41 inches/year <br />(1.1175 feet/year). All discharge from the pits will be based on infiltration from precipitation. <br />The area of the East Pit is approximately 46 acres, the area of Barren Ridge is approximately <br />• <br />R1.053\3\03-29-95(9.39am) <br />9 <br />