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,~ ~ • <br />Rich Domingue -2- July 22, 1982 <br />For this reason, I recommend that we approve ARCO Coal Company's request <br />to place underground development waste within the backfill of the Bear <br />No. 2 Pline's portals, with the following conditions: <br />(1) ARCO must precisely determine the volume of underground develop- <br />ment waste to be disposed within the backfill. That quantity should be <br />limited to 20% of the total volume to be backfilled at the portal bench. <br />(2) ARCO should homogeneously mix its underground development waste <br />with the backfill materials derived from the Bear mine surface facility <br />area. Mixing should be accomplished through standard earth work techniques <br />at an appropriate staging area, to be approved by the Division prior to <br />the placement of hackfill. <br />(J) Backfilling of the Bear No. 2 portal should conform with the <br />approved construction specifications. Faterial must be placed in maximum <br />2-foot thickness, horizontal Zifts. That material should be compacted <br />to a minimum of 95% of the standard Proctor maximum density, as determined <br />using ASTPf standard tecnhique D-698. <br />(4) Four feet of backfill material not contaminated by the underground <br />evelopment waste shall be used to cover the backfilled spoil throughout <br />t portal area. <br />(5) The final configuration of the backfilled portals shall conform <br />with one of the alternatives contained within the approved Bear No. 1 <br />d No. 2 mine plan. <br />(6) ARCO must assume all responsibility for the proper reclamation of , <br />the Bear No. 2 Mine's portal area, in conformance with the approved plan, <br />as amended by this revision. <br />(7) ARCO must assume all responsibility for completion of the required <br />slope stability monitoring program, contained within the approved Bear No. <br />1 and No. 2 Mine plan. <br />(8) ARCO Coal Company's reclamation bond should be adjusted to reflect <br />the additional responsibility for the reclamation of the Bear No. 2 Mine's <br />portal facilities. <br />/mt <br />cc: Ed Bischoff <br />