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5. There will potentially be increases in total dissolved solids (TDS) and other <br />parameters. <br />The four wells which have been sampled since 1980 are MW-10, 23, 16, and 65. Four <br />constituents will be discussed here because they represent analytes commonly <br />demonstrating mining impact in Colorado. They are sodium, sulfate, iron and total <br />dissolved solids (TDS). <br />Well MW-1Q a well surrounded by the mine workings of the Southfield operation, <br />shows no impact. Sodium and sulfate levels decreased by 50% from 1980 until the well <br />recently collapsed, diminishing to around 100 mg/l. TDS decreased to about 400 mil <br />from consistent readings aoound 1000 mg/I in the eazly 1980s. Iron also decreased <br />through the twenty yeazs of monitoring and was consistently below 0.1 mg/1. There was <br />no negative impact detected. <br />MW-16, a well cross-gradient of mining in the JOL seam, showed more vaziation with <br />sodium, sulfate and total TDS rising in the early 1980s, but dropping to near baseline <br />levels by 1995. Iron was never extremely high, and was most recently <0.1 mg/1. <br />Well MW-23, lies up-gradient of the Southfield mining, but surrounded it is by older <br />mine workings. The analyses of MW-23 groundwater show steady levels of the four <br />analytes through most of the monitoring period. From 1983, sodium has been present in <br />the low to mid 200 mg/I range; sulfate in the low 200s to high IOOs mg/l. TDS was in <br />the high SOOs mg/1, dropping to the low 200s in the last few yeazs. Iron has always been <br />in the low range of <0.1 mg/[. This is what would be expected of an up-gradient well. <br />Well MW-65 represents a reasonable down-gradient well for the mining at Southfield. <br />The well is situated neaz older mine workings, but using the earliest analyses as a <br />baseline for the area provides a view of the effects through time that mining may have <br />had on the down-gradient groundwater. The data show no impact from the Southfield <br />operation. Sodium remained steady through the years in the range of 400 to the low 500 <br />mg/1. Sulfate content dropped from the range of 500 mg/1 in the early 1980s to levels <br />consistently below 100 mg/i. TDS has remained reasonably constant at around 1100 mg/1 <br />during the monitoring period. Iron has been mostly <0.1 mg/1 and always <1 mg/1. <br />The conclusion is that there has been very little or no impact by the Southfield Mine to <br />the groundwater quality. The water was certainly impacted by historic mining all aoound <br />the Southfield Mine. The baseline analyses, taken at the beginning of the permitting <br />period, show the quality of the groundwater at that time and there has been no significant <br />deterioration since then. <br />Surface Water <br />Oak Creek flows adjacent to the loadout area where flows are often ephemeral according <br />to the AHR. Newlin Creek is diverted upstream from the mine site and is an ephemeral <br />stream across the mine site. Because of drought conditions, there was no flow in the <br />