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• dewater and drain the recent failure a pre-slide factor of safety <br />value, although low, will be realized. Even with the current near <br />saturated state of the existing slide material, where the greatest <br />threat to additional instability would be aggravated by additional <br />spring season rains, the risk of further instability is relatively <br />low with the implementation of the measures proposed. Until the <br />access road is reconstructed, the possibility exists for continued <br />progressive failure above the slide area. Although a progressive <br />failure would be relatively small, it could be devastating to the <br />ventilation fan because of the fan's close proximity to the bedrock <br />highwall. <br />Rule 4.03.2(3)(d)(ix) states: "The minimum safety factor for <br />all embankments shall be 1.25, or such higher factor as the <br />Division may specify. A lower safety factor may be approved if <br />geotechnical analysis demonstrates that it will not result in <br />significant environmental harm or harm to the public health and <br />safety". As stated before the factor of safety for the slide area <br />• falls between 1.0 and the peak strength condition factor of 1.255. <br />Although the peak strength condition factor is higher than the <br />minimum factor required by the Division, the possibility of the <br />elide to obtain that factor and maintain it is remote. it is <br />important to note that if the slope's intermittent slides progress <br />to the valley floor at the toe of the slope it is unlikely that the <br />material will reach the river due to the physical distance from the <br />toe of the slope to the river bank. If this scenario is realized, <br />no river contamination will occur that could threaten the health or <br />safety of down stream users of the North Fork of the Gunnison <br />River. In addition, because of the slopes intermittent localized <br />debris movements and the limited use of the portal access road, <br />relatively safe access of men and equipment can be maintained. RMG <br />estimated there would be a 58 reduction in stability for the post <br />reclamation configuration of the bench and access road. Because a <br />pre-slide factor of safety is anticipated for the post-drained <br />slide area, the minor reduction in stability of 58 will be <br />. applicable. <br />21-12 <br />