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Marilyn Kent October 6, 2006 Page Two AGGREGATE INDUSrRlES however I believe that you indicated that the current water supply should be sufficient for your needs throughout the fall and winter since you are no longer watering lawn and gazden areas. We therefore agreed that pumping water directly to you will not occur until needed next spring. AI expects to resume and complete mining of the phase east of your property next year and a pond will then remain directly east of you. Upon completion of mining this phase, AI does not anticipate any additional activity associated with its Tucson operations in the near future. Cessation of mining activity will eliminate any impacts to groundwater from AI's operation at that time. We understand your concern regarding potential effects in the future when and if the Tucson South mine cells and the Challenger cells aze lined. As you aze aware, AI has been working with the City of Aurora with regazd to the Tucson South operation, and we are all committed to address any negative impacts that may affect your well at such time as a slurry wall is installed azound the Tucson South mine cells. I am enclosing a copy of the Groundwater Modeling Study on Hydrologic Effects of Mining (August 2004) as prepazed for AI by Tetra Tech RMC in support of the permit applications for the Tucson South project. The report contains a map that shows pre-mining groundwater elevation contours (Figure 4), as you requested. I would note that the report also indicates in its conclusions that the most widespread drawdown (of groundwater) was found to occur during the dewatering of the Challenger Pit, Baseline Mine and the southern portion of the Roger Pit (AI's active mining azea east of you). It appeazs that these are the conditions that aze being encountered at this time. I would again emphasize that, as AI completes its excavation activity in this azea in the coming year, groundwater impacts from its operations will cease, and the remaining pond should help to maintain the water level in your well. Until such excavation activity ceases, however, AI is committed to mitigating for its impacts. We again appreciate your time and encourage you to contact us with any concerns that you may have with regazd to our operations. Eric Gavin, who is the plant manager at AI's Brighton Mine, is assuming responsibility for the Tucson site, and he can be reached at (303) 250-4080. I have discussed the foregoing with Eric, and he will be contacting you to introduce himself. You aze also welcome to contact me at (970) 336-6526. Very truly yours, ~~~ ~ ~~ Connie N. Davis Land Resources Assistant Enclosure cc: Berhan Keffelew, Colorado Division of Reclamation, Mining & Safety Aggregate Industries-WCR, Inc. Connie N. Davis, Land Resources P. O. Boa 337231, Greeley, CO 80633 (970)336-652b