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Mr. Alex Schatz December 29, 2006 Page 3 of 6 from all 15 monitoring wells/piezometers during 2006 on the following dates: April 27, May 4, May 11, and May 18, 2006. Martin and Wood personnel made measurements on the wells that were able to be located on December 5, 2006. The attached map presents the locations of the wells based on GPS data collected December 5, 2006 and on location data provided by Colorado River Engineering. As noted in 21.b., above, and based on the data collected in 2006, the ground water gradient and implied flow direction is to the northwest. The installation of two additional piezometers was requested by the DRMS. We feel that monitoring well MW3 (Exhibit C-1) or one of the existing wells located near the southeastern corner of the site could be utilized for up-gradient data. To establish adown-gradient water level measuring point beyond the well referred to as W1 on the Colorado River Engineering map, a new well located near the property boundary on the northwestern side of I-70 would have to be installed. Note, however, that it is our opinion that the existing wells provide information sufficient to fully assess the ground water conditions at the site. 21.d. The DRMS requests information on the Comprehensive Ground Water Monitoring Plan. The Comprehensive Ground Water Management and Monitoring Plan is being developed by Banks and Gesso, LLC and Mr. McDcrmid. This plan, as currently drafted, incorporates trigger points based on a two-foot or greater change (from the seasonal average developed from baseline measurements) in the water level at any of the monitoring wells. If such levels are not consistent with the levels at other wells across the site, indicative of a specific conditions developing at a particular location, the Division will be notified and there will be a review and report provided to DRMS within 30 days. Based on our experience with similar grave] mining operations and mitigation plans, it is our opinion that the proposed trigger points should provide for protection of local wells, ditches, water rights and wetlands/woody riparian areas. 2i.e. The DRMS inquires as to the time of year simulated in the MWI model and requests information on the maximum pumping rates planned for each cell and the timing ofdewatered activities for each cell. The ground water flow model that was developed was a generalized model that was not intended to reflect any specific time of year with respect to the water table conditions. As noted above, there are no strong data to date indicating any significant seasonal fluctuations, although it is recognized that further long-term data collection may reveal such variations. The modeling work canted out indicates that the pumping rates required to drawdown the water in Pit 1, with balanced recharge to the wetlands area being can'ied out, would require a pumping rate of approximately 35,000 gallons per minute. Due to the relative location of Pit 1 to the river and the large wetland areas, it is expected that the pumping rates predicted for this mine cell represent the maximum that would be required for any of the pits. The rates for Pit lwould thus be generally higher Martln and Wood Water Consultants, Inc.