2011-06-29_PERMIT FILE - C1981019 (8)

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Changes to the Reclamation Bond Cost Estimate Due to TR -81 The analysis is presented to evaluate the changes in the reclamation bond amount of $68, 224,123 originally proposed in February 2010 due to the impact of the approval of TR- 81. The only change attributable to TR -81 is that resulting from changes in the dimensions of the temporary spoil pile that were adopted during the course of the TR -81 approval process. Although the total volume of spoil does not change, the revised geometry does result in a slightly higher pile than that used to develop the original bond estimate in February 2010. The higher peak elevation of the spoil pile in turn causes a decrease in truck hauling costs, limited to the uppermost lifts of the spoil pile. Because this change produces a small adjustment in the overall bond amount, it is best handled as a simple and tightly focused revision to the previous detailed estimate. There exist two "worst case" 2012 bond surfaces presented on attached Figure 1. The scenario depicted on the left panel of Figure 1 represents the conditions assumed for the original proposed bond amount of $68,224,123, as submitted in February 2010. While that bond calculation was based on an earlier version of Map 45, since changed during the approval process of TR -81, the estimate was nonetheless based on the assumption that the TR -81 package would be approved. As such, the bond calculation already included the extended toe locations of the two valley fills (East and West Taylor Fills). However, it did not anticipate changes to the East Pit temporary spoil pile that were adopted during the TR -81 approval process. This submittal addresses those changes and their impact on the total bond amount. The right panel of Figure 1 depicts the condition of the temporary spoil pile as it has evolved through the permitting progress of TR -81 from its initial submittal in September 2009 to its revised geometry in February 2011. The most significant change in the temporary spoil pile is an increase in its height and a widening of the area above elevation 8000 ft, as indicated in the red hashed area of the right panel of Figure 1. There are no significant changes in the 2010 topography in the West Taylor Fill area. It should be noted that throughout these revisions, the total volume of the temporary spoil pile has not changed, but the location and elevation of the approximately 10.1 MCY shown in the red hatched area has changed. The haul distances and corresponding earthmoving costs associated with this 10.1 MCY therefore need to be adjusted to match the now approved TR -81 pit and spoil pile configuration for the "worst case 2012" condition. It should be noted that the adjustment applies only to this volume, and only to the minor changes in haul distances. It can be observed by comparing the left and right panels of Figure 1 that the center of mass of the temporary spoil pile has actually moved about 728 feet closer to the South Taylor pit, while the height of the spoil pile has increased about 25 feet, adding back about 500 additional feet of ramp length. The net effect of this is a shortening of the average haul length above El. 8,000 by about 228 feet and a consequent marginal reduction in cycle time. This is the basis for the change in direct cost in the bond calculation.