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Section 3 Controlled Dumping to Achieve Rock Sorting that Results Both in a Filter System Over the Underdrain Built by Controlled Placement and Prevents the Formation of Voids that Could Adversely Affect Mass Stability. As stated in Section 2, weathered material was utilized for road and ramp construction around the perimeter of the fill area. Two mining methods were incorporated into the operation to segregate the weathered material for road and ramp construction from the competent rock. The first method was to take a narrow cut near coal seam outcrop. Once the narrow outer edge cut was complete, the shovel was backed up and ramped up to remove the top 15 (approximate) feet of weathered material. Once these steps were complete and the ramp system complete, the shovel was positioned to take the lower lift of competent rock and construct the various lifts incorporated into a dump plan. To achieve the required material sorting, the dumps were designed to maintain a minimum 50 foot lift while crossing the controlled underdrain system. Four dump levels were designed from the ramp system to construct the natural sorting fill over the controlled underdrain. The dump levels included the 7675 level, 7725 level, 7775 level, and 7825 level. Natural rock sorting was monitored on a daily basis as the toe of each dump level encroached within 50 feet of the controlled underdrain. • Dumping across the underdrain system began on December 8th at 7675 level. Photograph 37 shows the 7675 level reaching the controlled underdrain. Natural rock sorting created an excellent gradation in size distribution. Photograph 38 is a close up taken at the toe of the 7675 dump. Note the angular large rock interlocking and elimination of excessive voids by relatively smaller rock, The hard hat in the left forefront and a standard survey lath in the right forefront is provided for scale. The 7675 dump was stopped short of tieing into the south slope of the fill area due to the accumulation of snow and steepness of the slope. The decision was made to clear the snow and construct a key cut to tie the fill into the steep slope. At this point the 7725 dump level was advanced toward the controlled underdrain. When the snow removal and key cut were completed, the 7675 dump was tied in. Photograph 39 shows the 7725 dump advancing over the controlled underdrain and nearing completion of the 7675 dump level. Photograph 40 shows material sorting as the 7725 dump advances across the underdrain. Note the hard hat in the lower front for scale. Photograph 41 and 42 show the 7775 level at the edge of the controlled underdrain. Photograph 41 shows part of the ramp system to the high dumps while photograph 42 is intended to show the rock gradation. Note that access by foot to the toe of dump areas was both cumbersome and un-safe from the 7775 level and 7875 level. Close up pictures were no longer taken. Photograph 43 shows the 7775 dump advancing across the controlled underdrain. This photograph is a zoom lens shot taken from on top of the 7725 dump level. Section 3 -page 1