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<br />Memo to Tony Waldron <br />Bowie No. 2 Geotechnical Adequacy <br />page 9 <br />interprets "structures" to include any and all manmade structures, including water <br />management devices, such as ponds and irrigation ditches. The application contains <br />mitigation plans for the watering ponds. This deficiency can be easily solved by including <br />a brief discussion of stock watering ponds and mitigative methods. <br />2.5 LANDSLIDES <br />As discussed under other geotechnical topics, the Division believes the existence of <br />historic and modern landslides within the permit area constitutes a significant <br />geotechnical concern for the proposed Bowie #2 mine's operation and reclamation plan. <br />The preparer is correct in observing that no specific criteria are available for the <br />delineation of specific subsidence-related landslide hazard increase. This topic is better <br />addressed under the specific sections relating to stability of the operating facilities, such <br />as roads and portal benches, and the reclamation plan. <br />The Division does believe it would be appropriate to visually inspect known historic and <br />modern landslides, during the periods immediately following retreat extraction in their <br />immediate proximity. The applicant should propose a detailed inspection methodology to <br />detect subsidence cracking or rejuvenation of movement to the potentially effected <br />landslides. This should include inspection immediately following the annual ground water <br />high stand of late June, during which the majority of landslide movement normally <br />occurs. These inspections should be conducted annually in areas undermined for an <br />appropriate period of time following retreat extraction, to verify negative impact from <br />subsidence. <br />4.0 CONCLUSIONS AND RECOMMENDATIONS <br />Many of the preceding comments also apply to the reiterated statements included by the <br />preparer of Exhibit 15 within this summary section of the report. <br />SUBSIDENCE HANDBOOK <br />PJlany of the preceding comments also apply to the reiterated statements included by the <br />preparer of Exhibit 15 within the Subsidence Handbook mitigative methodology <br />discussions of the report. <br />SURFACE WATER RESOURCES -PONDS <br />Monitoring of these stock ponds above the areas of potential subsidence should be <br />monitored prior to, and frequently during, the annual stock watering season. Monitoring <br />