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-51- <br />The operator has demonstrated that the haul road and access roads are stable <br />and will continue to meet the performance standard. The demonstration was <br />supplied in a report (Phase II - Geotechnical Stability, by Merrick and <br />Company) submitted in response to stipulation No. 14 of the 1981 Orchard <br />Valley Permit; and which is included with the Permit Application in Volume 6. <br />The Division has approved the alternative road specifications based on this <br />demonstration. <br />The property owner has requested that the benched areas remain and be tied to <br />an access road. CWI has committed to removing the asphalt between Steven's <br />Gulch and the crushing and screening level and performing finish grading of <br />the road. <br />In August, 1986 CWI submitted a permit revision application to construct new <br />portal facilities in the East Roatcap Creek Valley. This application proposed <br />the construction of anew portal facility and haul road, because the existing <br />portals at the Orchard Valley Mine had been rendered unuseable by the <br />underground coal mine fire. The applicant proposed to upgrade an existing <br />public access road to serve as a coal haul road to the proposed portal bench. <br />The geotechnical specifications are found in Yolume 6, prepared by Golder <br />Associates, Consultant to CWI. This appendix presents the results of <br />geotechnical investigations, stability analyses and detailed engineering <br />design for the portal bench cut and fill and the accompanying haul road. The <br />stability analyses are based upon projected cut slope configurations and <br />material mechanical properties obtained from material sampling and laboratory <br />analyses. <br />Stability analyses were completed for cross/sections chosen at road stations <br />believed to represent potentially critical slope stability situations along <br />the proposed upgraded haul road. Asa result of this slope stability <br />analysis, CWI amended its original proposed road cut slope configurations to <br />use a Hilfiker wall, or equivalent, retention system. The retention system <br />will be utilized as depicted on Sheet 7 of 10 of the Golder Associates report, <br />entitled "Haul Road (1)", to reduce the unretained cut slope heights to a <br />maximum of 30 feet. The Hilfiker treatment will be applied between road <br />design stations 29+50' and 36+50'. Unretained cut slopes will not exceed a <br />maximum slope gradient of 1.25h:1.Ov (horizontal to vertical), unless an <br />appropriate slope stability monitoring program has been approved by the <br />Division. With an approved monitoring program, cut slopes will be allowed to <br />reach a maximum slope gradient of 1.Oh:1.Ov (horizontal to vertical). The <br />stability analysis, determined a minimum operational static slope safety <br />factor adjoining the upgraded haul road of 1.72. <br />CWI will remove and reclaim that portion of the haul road constructed to <br />connect the existing public access road to the proposed portal bench <br />embankment across East Roatcap Creek (design plan road Station 32+50' to <br />38+50'). In addition, CWI will partially backfill the road cut slopes during <br />reclamation, in order to narrow the road from an operational width of 26 feet <br />to a width of approximately 15 feet, similar to that of the pre-existing <br />access road. This partial backfill will provide buttress to the retained cut <br />slopes of the haul road, increasing their static slope safety factors. <br /> <br />