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<br />Memo to Greae Syuire 3 September 6 1999 <br />The total direct cost for the pit lining project is derived by summing the individual task costs listed <br />above yielding $203,986.50 or $1.55/ccy. This reclamation cost amount is included in [he total amount <br />of bond tabulated in the attached cos[ summary form and in the total amount of bond required under <br />stipulation no. 2 listed below. <br />Bond to Install Ground Water Interceptor <br />Under the proposed mine plan, one worst case bond forfeiture scenario would result if Phase 1 were to <br />be mined and the clay liner installed, thus cutting of ground water flow to the south, but the ground <br />water interception system had not yet been installed. To bond for this situation, an estimated cost to <br />install the ground water system should be included in the bond per the following task list. <br />• The proposed interceptor ditch has a cross sectional area of 126 s.f. and a length of 4800 feet. This <br />yields a volume of 22,400 bank cubic yards of earth to be excavated. The cost estimated to <br />excavate to ditch is $14,025 as tabulated in the attached estimating form for excavator work. Note <br />that the cost to strip and replace topsoil and to revegetate the ditch disturbance is included in unit <br />costs tabulated elsewhere in the reclamation cost estimate. <br />• The plans illustrated on the Exhibit F map received 8/27/99 show 290 linear feet of 18-inch culvert <br />to be installed in the ground water interceptor system. The cost to install l8 inch culvert is listed as <br />$20.12 per linear foot in 1998 MEANS Site Work and Landscape Cost Data yielding a total direct <br />cost for culvert installation of $5835. <br />The reclamation cost amount of $19,860 for ground water interception is included in the total amount of <br />bond tabulated in the attached cost summary form and in the total amount of bond required under <br />stipulation no. 2 listed below. <br />Bond to Backtill the Northeast Corner of the Pit <br />The applicant states that the northeast comer of the pit will be reclaimed such that the pit slope will be <br />no closer to the river than 400 feet. In a worst case bond forfeiture scenario, the northeast corner of the <br />pit will have been mined to the lines illustrated on the Exhibit C map submitted 8/27/99 and the State <br />would require sufficient bond funds to backfill to 400 feet from the river. This is a backfill area of <br />approximately 2.75 acres. With a pit depth of 16 feet, approximately 71,111 compacted cubic yards of <br />fill would be required. Assuming that excess overburden will be available for backfilling, and using the <br />applicants proposed unit cost for backfilling of $1.25 per cubic yard, the estimated total direct cost for <br />this project is $88,889. This total is included in the total amount of bond tabulated in the attached cost <br />summary form and in the total amount of bond required under stipulation no. 2 listed below. <br />Another concern relative to the proximity of mining to the river in the northeast comer of the pit is the <br />exposure period during which the pit will be closer than 400 feet to the river. In order to reduce the risk <br />of the river breaching into the pit, stipulation no. 3 listed below is applied to the approval. This <br />stipulation reduces the probability of a 100-year flood breaching into the pit to approximately 2 percent. <br />