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-5- the radon flux would not be substantially affected in terms of emanations since the cover would be reduced only along narrow cracks of limited extent and not over the entire surface. If the clay layer were entirely removed, the flux would remain well below the 20 pCi/m2-sec, criterion. Encapsulation of the low-grade ore within the upper strata of the respective overburden dump structures might increase geomorphic stability. However, the two stockpiles are presently located on the clay-lined bases and it is not anticipated that additional fill material will be placed around them. It would be difficult to further encapsulate the low grade material now that overburden dumps are essentially complete at the location of the low-grade ore stockpiles. From the standpoint of geomorphic stability, the existence of diversion channels upgradient of both piles limits the watersheds affecting the stockpiles. Thus less erosion of the piles will occur than if the watersheds were as large as those affecting the overburden dumps. Item: Final reclaimed drainage and erosion control system, including South Pit Lake and flow attentuation areas. Response: Concern is re-expressed regarding susceptability of the flow attentuation areas to settlement disorientation and the subsequent potential for increased erosion and discharge from the affected areas. As stated above, the role of the flow attentuation areas in drainage control was not in- cluded in design flow calculations. Flow attentuation areas will require regrading during reclamation and will be designed to accommodate settlement to the extent possible. Dr. Pendleton also expresses concern regarding the adequacy of surety in the event that the South Pit is not mined to completion. Homestake fully intends to complete development of the South Pit, as reflected in the proposed reclamation plan amendment. The planned South Pit development will result in a larger total area of surface disturbance than currently exists without South Pit development, The proposed amendment and associated surety reflects the larger disturbed areas and should therefore result in adequate surety protection for the State during the interim period of mine development. The calculation of the surety, as related to grading of the slide area, is discussed in response to the following item. As a result of current uranium market conditions, Homestake will be applying to the board for temporary cessation during early 1985. The subject of adequate surety during this interim period of temporary cessation can be more properly addressed at that time. Item: Recalculation of reclamation costs based upon proposed planned amendments. Response: Dr. Pendleton's observations focus principally on .the adequacy of surety in the North Pit slide area. As discussed above, the North Pit landslide mass will be allowed to reach its equilibrium configuration prior to initiating reclamation. The equilibrium, or final, configuration will be determined through monitoring and use of "success criteria" as was also discussed previously. If this final configuration is not that presently projected in the reclamation plan, further major modification of the topographic surface to exactly meet the configuration curently in the plan would not be necessary. Therefore, significant expenditures for regrading of the landslide are not anticipated, or included in Exhibit L. The $26,460 shown in the Exhibit is for final "dressing" and shaping of the landslide material. In addition, $44,000 has been included for revegetation of the landslide mass under Section II of Exhibit L.