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least one year of average precipitation. The area is currently under full reclamation liability. <br />Mass movement occurred in the reclaimed Neck Pit in portions of a crack, approximately 1,500' <br />long, running roughly north -south and centered on the junction of former Haul Roads B and D. At <br />the approximate centerpoint of the crack, a slide roughly 250' in length occurred. The offset along <br />the scarp was approximately 25' high. The slide area is shown on Figure 1 of this document, and a <br />detailed description of the Division's observations can be reviewed in the Division's May 16, 2011 <br />and July 6, 2011 site inspection reports. This area had been released from Phase I liability with <br />approval of the SL -2 application. <br />A large slide also occurred east of Pond 013. The scarp of this slide was approximately 500' in <br />length, with a vertical offset of 30', extending beyond the area currently approved for disturbance. <br />This area is shown on Figure 2 of this document. Observations of the slide are detailed in the <br />Division's May 16, 2011 and July 6, 2011 site inspection reports. This area had been released from <br />Phase I liability with approval of the SL -2 application. <br />All of the slide areas were evaluated by the Division, with assistance from the Colorado Geological <br />Survey (CGS) in July of 2011. A geotechnical consultant for SCC also participated in the <br />evaluation. Details of this evaluation can be reviewed in the Division's and CGS's July 6, 2011 site <br />inspection reports. The evaluation included site visits, review of previous Division inspection <br />reports and aerial photographs, and a review of the 2001 geotechnical analysis (Attachment 6 -A of <br />the permit application package) for these three areas. The 2001 analysis was developed in response <br />to a Division requirement to further investigate areas that were mapped by the CGS in 1977 as <br />unstable and /or potentially unstable. The Division, CGS, and SCC attempted to determine a <br />remediation plan to promote long term stability in all three areas. <br />It was determined that the best course of action for the Pond 012 area was to implement the <br />previously approved and nearly completed remediation plan. The recommendation for the Neck Pit <br />and Pond 013 areas was to essentially leave the slide areas in their post- movement configuration, <br />with minor manipulation to facilitate drainage and ensure safety of the public and wildlife utilizing <br />the area. The scarps of the Neck Pit and Pond 013 slides were graded to lessen the slope to ensure <br />that the areas could be safely traversed by wildlife and humans, and drainage channels were <br />excavated to prevent saturation of the slide mass. The toe areas were left intact to buttress the <br />remaining undamaged uphill blocks. Remediation work in all three areas was completed in the fall <br />of 2011. <br />III. PROPOSED DECISION <br />Based on the observations above, and because the Pond 013 and Neck Pit areas were unstable and <br />required regrading, the Division has determined that they do not meet the requirements of Rule <br />3.03.1(2)(a) for Phase I bond release and that SCC should resume Phase I liability on those areas. <br />The Division also asserts that because of the history of instability in all three of these areas they will <br />not be eligible for Phase I bond release until SCC can demonstrate that the remediation areas remain <br />stable through at least one year of normal (average) precipitation. Accordingly, the Division <br />proposes to increase the required surety for Seneca Coal Company, LLC's Yoast Mine. This <br />proposed decision will reinstate SCC's liability for backfilling, grading, and drainage <br />