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CMWDA-4 has been designed with the intention of first excavating native soils in order to create <br />an available area for placement of the coal mine waste. The Buckhorn Geotech report dated <br />February 1, 2007 evaluated overall excavation slopes of 2.511:1V and 2H:1 V. These slopes <br />resulted in acceptable upper waste fill slopes of 2.5H:1 V and 3H:1 V, respectively (page 3, 5`" <br />paragraph). The May 2009 Buckhorn Geotech report steepens the acceptable excavation slope <br />(assuming a 3:1 upper waste fill slope of 3H:1 V) from 211:1V to 1.3H:1 V. Presumably it is this <br />steepening of the acceptable excavation slope that accounts for much of the potential increase in <br />the volume of CMWDA-4. Section D-D' of Volume IX Figure 1 illustrates the relative locations <br />of the original ground surface and the proposed ground surface. Missing from this Section is a <br />line showing the proposed excavation surface. Please modify Section D-D' to represent the <br />approximate limits of excavation that have preceded or are expected to precede the placement of <br />coal mine waste in CMWDA-4. <br />The map view of Volume IX Figure 1 seems to indicate that the northern portion of CMWDA-1 <br />has effectively been absorbed into CMWDA-4. This and other associated changes should be <br />reflected in Volume IV of the permit. <br />Reclamation Cost Estimate Review <br />The Division has not fmished its calculation of the reclamation cost estimate for TR-64. Additional <br />information is needed before the cost estimate can be completed. <br />10. The operator is proposing to increase the size of Gob Pile #4 by increasing its maximum height, <br />lowering the elevation where it starts and increasing its acreage. Based on cross-section D-D', the <br />maximum height of the pile is being increased from 6,230' to 6,235' and the starting elevation of <br />the pile is being decreased from 6,110' to 6,080'. As a result of these elevation changes, the area <br />of the pile is being expanded to the north and the south. Based on the Division's digitizing, the <br />area of Gob Piles #1 and #4 (taken together because they converge) increased from 10.3 acres to <br />11.3 acres. The increases in area extend into what appears to be undisturbed lands both above and <br />below Gob Pile #4. BRL has not included any detail regarding the topsoil and subsoil stripping <br />that will be required in this undisturbed area. Detailed information regarding the increased area <br />and the volumes of topsoil and subsoil that will need to be salvaged will be required. <br />11. Based on the increased maximum elevation, starting elevation and area noted in question 1 above <br />and the increase in capacity of Gob Pile #4 (from 300,000 cubic yards to 450,000 cubic yards; <br />Volume IX, Page 4) the surface area of the pile will necessarily increase. This increase in area will <br />require additional subsoil and topsoil to properly cover the pile. Please recalculate the volumes of <br />subsoil and topsoil that will be required to cover the pile with the required depth (three feet of <br />subsoil and one foot of topsoil). <br />12. Based on the Division's digitized areas of Gob Piles #1 and #4, which have increased by <br />approximately 1 acre, the operator's description of the disturbance in the second paragraph on <br />Page 11 of Volume IX will need to be changed. The operator states that the gob piles cover <br />approximately 34 acres and the topsoil piles cover approximately 2.3 acres. The increase in the <br />area of Gob Piles #1 and #4 (of approximately 1 acre) and any changes to the area of the topsoil <br />stockpile by Gob Pile #4 will need to be accounted for in these totals. These numbers will need to <br />be changed accordingly to account for the changes in the configuration of Gob Pile #4. <br />2