PERMFILE61597 - Laserfiche WebLink

Home Browse Search

both. As is stated in Comment #20, the drilling and completion of wells has the potential to affect ground water quality. The potential affects could occur due to commingling of aquifers along the well bores. No other activities proposed during development of the surface facilities have a reasonable potential to adversely affect ground water. The correct permit conditions protective of ground water relative to the potential for commingling along a bore are practice based conditions. The reclamation permit application requires the well casings be cemented along their entire leneth, and that cement logs be run and mechanical integrity testing be conducted. Each well completion must be certified and a construction report with all logging and testing results provided in accordance with the regulations for Environmental Protection Facilities (Rule 7.3) and the terms of the permit application. Practice based permit conditions, by their nature, do not require water quality baseline or monitoring. The activities proposed in the permit application that may affect ground water and that will require permit conditions protective of ground water in the form of numeric protection levels are all related to the requirement to isolate production fluid from the aquifers. No production fluid will be generated until heated barren solution is injected into the mining interval. Injection of solution is prohibited in the permit application until the ground water characterization study-is complete. Thus the baseline ground water information collected during the study will be valid, pre-mining ambient quality data, which can then be applied in the development of numeric protection levels for on-going monitoring. In objecting to the approval of the application, the commentors state that DMG will be vulnerable to pressure to establish less stringent standards if she standards are established after the project is underway. However, there is no subjectivity in the establishment of numeric protection levels. If the ambient quality is at concentrations lower than the ground water standard for a particular parameter, then the standard becomes the protection level. If the ambient quality is at concentration in excess of the standard, due to natural orpre-existing anthropogenic contamination, then the numeric protection level is set at the ambient quality. This narrative standard, as well as the table value standards for ground water are established by the Colorado Water Quality Control Commission. Also, in the case of the American Soda proposal any detectable release of production fluid to ground water would require corrective action, regardless of whether ground water standards are exceeded. Based on the foregoing discussion, it is not necessary to delay development of surface facilities at the Yankee Gulch Project to collect the required five quarters of ground water baseline information. Such a delay would not improve in any way the DMG's ability to require permit conditions protective of the ground water resource. Comment #21 Disposal well influence on baseline data DiVIG Response: The disposal well is operated under an underground injection control authorization from EPA unrelated to the solution mining activities proposed in the reclamation permit application. Any affect on ground water caused by the operation of the disposal well would be a component of the premining baseline condition. No disposal wells are proposed in the reclamation permit application under consideration.