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Plans (Dated Apri122, 1999) were submitted on Apri127, 1999, and were included in the administrative record for comment. These plans have been revised to incorporate all changes required by EPA and other regulatory agencies in response to public comments, discussed further in Response to Comment 6. The revised plans, dated December 23, 1999, have been incorporated into the Final Permit. The Permit requires the operator to establish a monitoring plan for both surface and ground water. As outlined in the April 22, 1999, Water Monitoring Plan, the operator was committed to obtaining at least 5 quarters of additional ground-water data from approved wells in the vicinity of the initial well field prior to commencing injection into the new wells covered by the commercial Permit. Further, the baseline data will be compiled and the baseline water quality characterization will be supplemented prior to commencement of any injection. Collection of additional baseline data from the new and existing monitoring wells commenced during July 1999. This will assure that commercial mining operations do not affect the characterization of baseline ground-water quality. The baseline data will be used for comparative purposes during commercial operations to determine if commercial mining is adversely affecting ground-water quality. Although not directly relevant to this Permit, it should be noted that the BLM and CDMG also requve the collection and review of baseline ground-water quality data prior to commercial injection under the terms of the Water Monitoring Plan approved in this Permit. As new mining "panels" are scheduled to come online, the Water Monitoring Plan will require baseline monitoring of those aeeas, as appropriate, prior to the start of any mining in that area. The EPA and other regulatory agencies (e.g., BLM, CDMG} recognize that the Water Monitoring Plan (which outlines the anticipated ground water and surface water monitoring required for this project) is a "living" document, and anticipates that revisions to the plan maybe necessary as more data are gathered across the project area of approximately 4,500 acres over a period of 30 years of operation. If the periodic review of on-going monitoring of wells in the active mining areas and the baseline results from new wells in planned expansion areas indicate that additional monitor wells aze needed because of hydrologic or geologic conditions, such as variations in direction of ground-water flow, EPA will require installation of additional wells at locations that will address those concerns. It should be noted that the installation and sampling of the initial baseline wells will address several objectives. A key objective is to evaluate vertical and horizontal hydraulic gradients and associated water quality at several multiple-completion sites. These data will help verify information in Saulnier's report (Saulnier, 1999) suggesting the likelihood of cross- contamination from historic activities. This objective necessarily requires that slight differences in ground water flow direction between the upper aquifer (i.e., northeasterly flow) and lower aquifer (i.e., easterly flow) systems may be a secondary consideration for some well locations. EPA does not agree with the concern that having wells which are not exactly lined up on the actual direction of ground-water flow negates the usefulness of the baseline data. The presence of the cross gradient well will assure that there is always an up-gadient and down-gradient well. Additionally, well locations were purposefully selected to account for possible variations in flow from that assumed. Therefore, the wells are expected to provide up-gradient and down-gadient baseline and operational information relevant to at least portions of the first 5-year mine panel, if not the 15