_GENERAL DOCUMENTS - C1981017 (229)

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REPORT OF RECLAMATION ACTIVITIES, COAL BASIN MINE 1999 The winter of 1998 / 1999 was characterized by relatively warm and dry conditions. During a site visit in late February, 1999, only two feet of snow was observed at the Mine 1 area (elevation 10,000 feet). Heavy snows occurred during the spring , bringing the total annual snow fall to near normal by early May. Rain occurred on a daily basis from mid-July through early September, delaying construction activities. Little precipitation occurred between mid-September and late November. This unusually extended dry period may have a negative impact on fall seeding efforts. GENERAL The road from Redstone to Coal Basin was opened by April 5. About a foot of snow covered the facilities area at that time. By April 29, most of the areas below the Rock Tunnel area were snow free and accessible. The Huntsman Project, completed in the fall of 1998, was the first reclaimed area to be investigated in 1999. During reclamation construction, due to the length of the reclaimed slope, it was apparent that a slope break was desirable. The reclamation contract specified the construction of a ten feet wide, slightly inclined bench to address the slope break concern. However, upon reflection, it was realized that snow accumulation and differential melting of snow on bench slope breaks generally lead to their failure, resulting in large gully development. This seems to be most prevalent on north facing slopes. Therefore, dozer dips were created to act as slope breaks. Hundreds of dozer dips were created by placing a light dozer at the toe of the reclaimed fill slope. The dozer backed up the slope about ten to fifteen feet, dropped its blade and pushed forward (downhill)until a mound of topsoil six to eight inches tall accumulated at the blade. The dozer would then lift its blade and back up and repeat the process until it reached the crest of the slope, where it would move to the side and proceed to the base of the slope to start the process all over again. This occurred until the entire slope was covered by these dips. Observations made in early—to mid-May indicated that, for the most part, the dips functioned as intended. In some areas where the vertical spacing was too great, the dips had a tendency to drain at the edges, periodically forming small rills at these locations. Overall, the height and horizontal spacing of the dips appeared to be adequate to prevent significant gully formation. One small slope failure was observed near the base of the slope. The topsoil and the immediately underlying coal refuse apparently became super-saturated, and a small rotational failure occurred. The failure is less than five feet across at its head, and less than eighteen inches in depth. No drainage was observed from the failure zone, but it is suspected that drainage from within the coal refuse was the primary contributing factor to 2