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<br />Battle Mountain Gold facility up the Rito Seco drainage on the west slope of the Sangre De <br />Cristo Mountains. Other activities that might be potential sources of contamination to the <br />ground-water resources of the Alamosa Formation aze not viewed by the locals at the same level <br />of concern. <br />The mining company currently monitors ground-water quality in a number of ~Nells in <br />their project azea as well as a downgradient irrigation well on the Shalom Ranch. It is my <br />understanding that the municipal water supply is also sampled and tested by the mining company <br />on a limited basis. Based on discussions with staff of the Bureau of Mines and Geology, to this <br />point any impacts to ground-water quality have been confined to the Battle Mountain Gold <br />property. However, it was raised to my attention that a second irrigation well on the Shalom <br />Ranch property has been subject to deteriorating production due to corrosive conditions in the <br />water. The source of this problem has not yet been identified. It is recommended than the <br />SLWSD contact with the Costilla County Conservancy District (CCCD) for updates as this <br />problem is being further investigated. <br />RECOMMENDATIONS <br />Based on the analysis of information provided above, it is possible to recommend an area <br />for the installation of one or two monitoring wells as detection monitoring for protect on of San <br />Luis' drinking water supply. The bigger issues involve the need for such a monitorin;~ program <br />and the depth to which such sampling should be conducted at, <br />As stated above, at this time any impacts to ground-water quality from the Battle <br />Mountain Gold project seem to be limited to the permitted project property itself. There is a <br />distance of approximately 2.8 miles from the southwestern corner of the permit boundary to the <br />town's closest water-supply well. Estimating ground-water flow velocities based on ~;onservative <br />assumptions for aquifer properties, it would take a contaminant plume from the site <br />approximately 15 yeazs to reach the well via the ground-water pathway. However, this time <br />frame could be reduced if a release of contaminants to the Rito Seco drainage occurred. Under <br />this scenazio, contaminants would be transported rapidly via surface-water flow and could seep <br />into the shallow ground-water system over time and at points closer to the town's wa~.er-supply <br />wells. Such a transport mechanism would reduce the time for potential impacts to oc:ur to less <br />than the estimated 15 yeazs via the ground-water pathway alone but this combined m:.gration <br />pathway is not realistically quantifiable. This discussion is offered for consideration in <br />determining the need for a detection monitoring effort by the SLWSD above and beyond what is <br />currently in place and undertaken by the mining company. <br />With this in mind if it is the SLWSD's decision to proceed with a detection n-onitoring <br />program for the longterm protection of their source water, a potential locational area is <br />recommended for one or more monitoring wells. This area would be at a relative point <br />intermediate between the irrigation well on the Shalom Ranch and the town's primary water- <br />supply well as well as at a relative point intermediate between the diversion of the Rito Seco to <br />Salazar Reservoir and the town's primary water-supply well. This general locational area is <br />