2007-01-31_REVISION - M1986015 (2)

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MIN elevation of the adjacent land to be protected from all but the most significant floods required a very large amount of overburden. The overburden in the plant site is no[ expected to be removed once the plant site is closed. It could serve as an excellent area for a building site in the future. But, if at the end of the operation additional fill is needed for Phase 1 this material is a feasible source for a considerable volume [hat is very near where it would be needed. Another source of till, if needed, is shown on Exhibit C-4C. On the north side of Phase 2 just south of the highway is an area where [here is a considerable amount of overburden. There is also gravel in this area, but the overburden is far too deep to make mining economically feasible. Tf additional fill is needed, this area could be excavated down to the elevation of the southern boundary of this area so no basin is created in this area. Of course, if that is done, reclamation will need [o be applied. There is more information on [his aspect in the Reclamation Plan -Exhibit E. STEP 5: Mining Phase 2 and Linkages to Phase 1 GENERAL APPROACH: Requirement: All mining in Phase 1 and Phase 2 will be done from dewatered pits. DISCUSSION: The general approach [o mining the aggregates will be as a dry (dewatered) pit operation. That is, aggregate will be mined from a dewatered deposit. All mining will be done within a conventional dewatered pit. In Phase 1, ground water entering the main pit is pumped out via the dewatering circuit. In Phase 2, as discussed elsewhere, a groundwater barrier wall will be installed prior to mining. Therefore, dewatering will only be needed once with only minor amounts of maintenance dewatering once the deposit to be mined has drained. Requirement: Mining by any method other than the dewatered pit method described in this plan will require a permit modification prior [o changing the method of mining. DISCUSSION: Consideration is being given to possibly mining the Phase 2 area (and perhaps the remaining Phase I area) using a dredge rather than the dewatered pit plan. At [his time though that approach is simply an alternative being examined. Switching to that plan contains some significant problems with regard to acquiring water rights as well as some other issues. However, that approach would solve a great number of other problems with flood damages and impacts of dewatering on the groundwater system. The operator fully recognizes [hat if such a large change in [he method of mining was made much of the mining plan and perhaps part of the reclamation plan would also need to be Pueblo East Pit Amendment 3 (2007) Exhibit D Page 30 of 34