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Applicant's Response to Second Adequacy Letter Grand River Park Project, DRMS File M-2006-046 January 2, 2007 Page t4 be completed in Cell 1 before moving on the Cell 2, and completion of mining and reclamation in Cell 2 prior to de-watering and mining in Cell 3, and so on. Typically, operators of similar sites begin de-watering of Cell 2 prior to completing reclamation of Cell 1, i.e.: begin de-watering in the next cell to be mined prior to completing all backfill and re-grading, topsoil replacement, and pond filling requirements in the previous cell being reclaimed. As a result, the Division requests that the applicant commit to completing all reclamation measures in the preceding cell prior to initiation of de-watering activities in the following cell. As an option, the applicant may revise the existing groundwater model and assessment based on the maximum pit de-watering disturbance expected at any one time throughout the life of the operation, or the applicant may provide a comprehensive groundwater monitoring plan which verifies that all potential adverse groundwater impacts are being monitored and mitigated where necessary. The Comprehensive Groundwater Monitoring Plan will need to include the following components: 1. Map showing the location of all monitoring locations; 2. Frequency of monitoring water level measurements (Division recommends monthly measurements during mining); 3. Specific "trigger points" to determine when mitigation measures will be implemented', 4. Reporting requirements of water level measurements collected throughout the year & data summary; 5. Reporting requirements to the Division in the event a "trigger point" elevation is experienced during monitoring; 6. Specific mitigation measures that fhe operator will implement if trigger point are reached and, 7. Duration of monitoring (should be at least throughout the mining phase of the operation). The Division recommends that the "trigger point" be determined based on the maximum groundwater fluctuation (and elevation) expected throughout a normal year. However, the applicant should give special consideration to the groundwater fluctuations (and elevations) expected in the most sensitive areas that are likely to be impacted such as wetlands, willows, cottonwoods, etc to determine a "trigger' that will adequately protect these resources. The applicant concurs with the Division's observation regarding the typical practice of beginning to de-water a subsequent mining cell before turning off pumps in the preceding cell. Both mining and reclamation are most efficiently undertaken in dry mining cells. This underscores the special attention and very conservative approach that is being requested relative to groundwater effects and the hydrologic setting at the Grand River Park Project.