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Memo to Jim Burnell <br />West Elk Mine Landslide Stabilization Addendum Report <br />page 2 <br />stone columns and rolled concrete buttresses were installed to assist in <br />dewatering and pinning the landslide mass to the hill slope. <br />Barr included summaries of much of the groundwater and ground motion data <br />collected during 1997 - 2000. This data shows the expected annual rise in the <br />ground water table as a result of the spring melt and runoff. It also documents <br />the ground water effects of pumping and dewatering of wells and the stone <br />columns. The report concludes that the site has achieved additional stabilization <br />as a result of MCC's rehabilitative activities at the site. <br />In terms of relative stability of the landslide mass, I concur with Barr Engineering's <br />conclusion. One of my earlier reservations remains, however. In order to achieve <br />the maximum stabilization of the landslide mass, the dewatering wells and stone <br />columns require annual pumping to control the spring rise in the site's water table. <br />In order for this site to remain stable following reclamation, MCC will have to either <br />reconfigure the site to decrease the driving weight of the landslide mass, or <br />artificially continue dewatering of these monitoring wells and stone columns to <br />maintain the lowered ground water table. <br />My review has determined that the addendum report does complement the original <br />Barr report. I recommend that it be accepted by the Division and appended to the <br />MCC West Elk file documents. The final reclamation plan will have to reevaluate <br />and address the future dewatering necessity for the landslide mass. Ideally, <br />reconfiguration and reclamation of the surface facilities will eliminate the <br />necessity for active dewatering of the ground water wells and stone columns. <br />Otherwise a complicated maintenance program will be required as a portion of the <br />final reclamation and maintenance of the West Elk permit surface facilities area <br />following final reclamation. <br />cc: Dan Hernandez <br />doc: M:\COAL\JAP\MTG1 SLID.ADD <br />JP\JP <br />