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<br />29. Please describe what methods will be used to validate the assumption that <br />unsaturated conditions will be maintained within the embankment fill <br />throughout the life of the facility. Piezometers should be placed within <br />the embankment, and within the tails adjacent to the embankment inslope <br />to verify the design assumptions. <br />30. The model assumes 50% of the tailings disposal area is under deposition <br />at any point in time and thus 50% of the area will be evaporating. How <br />many days will an area of tailings be dry and subject to wind erosion? <br />What would be the maximum extent (acres) of area with moisture conditions <br />conducive to wind erosion and resultant dust generation? What measures, <br />aside from residual moisture, will be used for dust control? <br />31. The water balance calculations are referred to on pages D-73, D-74, and <br />6-3 as being found in Appendix I. The apparent correct reference is <br />Appendix K. <br />32. The units for monthly shallow lake evaporation are referenced in <br />Appendix K as "miles". The apparent correct reference would be inches. <br />33. A pan evaporation coefficient of 0.70 was used in the water balance <br />whereas 0.74 was given in Exhibit K of the original permit. Please <br />clarify. <br />34. The diversion ditches located upslope from the collection pond are <br />shown in cross-section on Detail 2 of Figure C-8 and in plan form on <br />figures C-3 and C-4. No peak flow calculations are provided to <br />substantiate their design, however the size appears to be conservative. <br />Please provide the following information on each diversion: <br />a. The upland drainage area, <br />b. The minimum slope to insure drainage, <br />c. An estimate of the size of runoff event which would overtop <br />the berm, <br />d. The erosion control measures to be utilized at the ditch <br />outlet downslope to the natural drainageway. <br />35. A small area without upland runoff control exists between the east and <br />south diversions. How will runoff from this small ridge area above the <br />tailings be handled? <br />36. On page D-61 of the original permit application, the statement is made <br />that details of the erosion protection/runoff control for the mill site <br />area will be provided upon completion of the mill design. Have these <br />been developed and, if not, what is the expected timing of this submittal? <br />37. Please describe briefly the diversion, sediment control, and irainage <br />crossing maintenance plan. <br />-4- <br />