Laserfiche WebLink
Site TDS Field EC Ratio Comments -? <br />NEW-2 <br />NEW-4 730 mg/I <br />1650 mg/I 1155 umhos/cm <br />2630 umhos/cm .63 <br />.63 <br />A TDS/EC ratio is remarkably consistent, however, at both sites, currently calculated at <br />.63. Mine inflow maps received by the Division in 1989 shows one mine inflow point <br />(#9) that is within about 1000 feet of NEW-2. The EC of this inflow was about 150 <br />umhos/cm, seeming to indicate excellent water quality consistent with Purgatoire River <br />water. This high quality inflow could dilute other ground water inflow to the workings <br />and result in dilution at NEW-2. No other plausible explanation is apparent for the <br />significant difference in TDS between these two wells that are separated by about 1900 <br />feet horizontally. <br />Alluvial water levels, as indicated in wells PAW-1 upstream of the mine and PAW-9 <br />downstream of the mine, continue to show normal variation due to seasonal influences <br />and no impact to alluvial water levels can be identified at this time. <br />Alluvial water quality generally remains slightly more saline than the surface water, <br />which recharges the alluvium, but is within an acceptable range for all known and <br />current uses. PAW-1TDS values in 2007 appear more normal for an alluvial well (170 <br />mg/1). Surface water TDS at adjacent station PRS-1 on the Purgatoire River was <br />measured at 190 mg/I. Possibly, PAW-1 is completed in the natural alluvium and not <br />affected by pre-law development waste that the surface water is exposed to above the <br />well location. <br />Quality changes due to mining are not apparent. Some alluvial water quality changes <br />would be expected due to the large amount of pre-law coal waste deposited in direct <br />contact with alluvial and surface waters. Water quality degradation from upstream <br />(PAW-1) to downstream (PAW-9) is again apparent but alluvial water quality at PAW-9 <br />remains relatively good and is acceptable for all uses. No impact to alluvial water from <br />mining activities is apparent. <br />Spring and Seep Survey <br />The spring and seep survey is no longer conducted since areas where springs were <br />present were released from liability through the bond release process. Past monitoring <br />indicated no evidence that mining activities reduced or impacted the spring flow or <br />quality in the area. <br />Summary <br />Monitoring frequency compliance was good with a few exceptions on timing of <br />monitoring in 2007. The Division reminds the operator to conduct monitoring in <br />accordance with the approved plan with normal allowances for access issues or other <br />unforeseen circumstances expected. Surface water quantity and quality changes are <br />small to non-existent, and due to the possibility of only limited discharge, surface water