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<br />plan the groundwater quality at the "series of wells" would not represent the <br />status of the groundwater system in the West Pit, but would, rather, measure the <br />condition of water quality in the Rito Seco alluvial aquifer adjacent to the <br />"window." The reversal of hydraulic gradient will continue throughout the period <br />of time the CDPS permit is in effect. <br />The reviewers suggest that sepazate dischazge points be assigned to all of the <br />seeps referred to in the NOV/CDO issued August 20, 1999. Each seep identified <br />in the NOV/CDO is a surface expression of groundwater flow in the vicinity of <br />the West Pit and the flow and quality associated with each seep is influenced by a <br />variety of factors including: (1) stage of the Rito Seco, (2) presence and location <br />of beaver ponds, and (3) upgradient groundwater flow. Thus, the potential exists <br />that there might be flow at one or more of the historical seep locations that would <br />not be related to groundwater flow from the West Pit. The performance <br />monitoring program implemented as part of the TR-026 water management plan, <br />includes the original seepage azea as a sampling point if there is sufficient flow to <br />collect a representative sample, which, in combination with the other water <br />quality and quantity information provided by the monitoring program, should <br />address the potential natural variability of flows associated with the historical <br />seepage azea. The monitoring program will be submitted under sepazate cover. <br />The reviewer should also note that there has not been flow in any of the original <br />seep locations since February 8, 2000. <br />Comment: <br />2. Long-Term Water Groundwater Dischazee Issues <br />It is our opinion that the TR-26 monitoring system (including the adjustments to <br />that system made by DMG subsequent to issuance of TR-26) should be <br />maintained throughout the long term. Specifically, wells within the flow <br />"window" should be identified as points of compliance, and dischazge through the <br />window and from the seeps must be quantified. Mining has permanently altered <br />the groundwater flow regime in the vicinity of the west pit (see TR-26 at pages 6- <br />10). Consequently, we believe "long term" here should mean until the applicant <br />can demonstrate that the West Pit is incapable of generating poor quality for an <br />extended period of time once the active remediation programs aze curtailed and <br />Ba!!(e .Nounmin Resources, /nc. HS/ GeoTrans <br />9 ~~fr?~• zooo <br />