PERMFILE63706 - Laserfiche WebLink

Home Browse Search

Applicant's Response to Second Adequacy Letter Grand River Park Project, DRMS File M-2006-046 January 2, 2007 Page 15 Based on the applicant representative's October 19 meeting with Carl Mount of the Division, we understand that the intent of the Division's request above is that no more than one mining cell should be subject to de-watering at any given time. The applicant agrees with this approach and hereby commits to de-watering no more than one mining cell at a time. As a technical clarification, the applicant anticipates that it will be possible to recover any dry surface deposits and conduct limited wet mining using excavators in, for example, Cell 2 while de-watering to facilitate final reclamation (of slopes to be submerged beneath the normal water line) is on-going in Cell 1. To protect groundwater, it is not necessary to literally cease all operations in one cell before proceeding to the next. Based on the language of Comment 21 d, the applicant's commitment to sequenced de-watering is sufficient to allow the applicant to rely on groundwater modeling as the primary means of accounting for likely groundwater effects under the proposed Reclamation Permit. However, in consultation with Martin & Wood Water Consultants and based on the above guidance provided by the DRMS, the applicant has developed the attached Groundwater Monitoring Plan as an additional layer of assurance that groundwater impacts will be appropriately contained and managed. e. The Martin & Wood Consultants groundwater model predicts significant, adverse hydrologic impacts to a number of resources (wells, wetlands, riparian vegetation, ditches) most of which are dependant upon groundwater. Please clarify the time of year that the model predictions account for (spring, summer, fall, winter), the maximum pumping rates that will be needed for each cell or phase of mining, the length of time each cell or phase will be in a de-watered state, and specific mitigation measures that the applicant will commit to for each cell or phase of mining to minimize the potential impacts. Please respond. While the Division interprets the Martin & Wood groundwater model to predict significant, adverse hydrologic impacts to wells, wetlands, riparian vegetation, and ditches, it is more accurate to summarize that the model showed groundwater surface drawdown potential, expressed in drawdown contours as well as tabular drawdown values for specific wells, to occur in the vicinity of de- watering operations. That the modeled drawdown potential "predicts significant, adverse hydrologic impacts to a number of resources" is a sweeping conclusion presented by the Division, not to be found anywhere in the groundwater modeling reports.