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Section 780.18 Ibl Continued. <br />On completion of mining in Pit 1 in January 1993, there was not sufficient economic <br />justification for a commitment to further development, therefore, Kerr concentrated <br />available equipment and other resources on reclamation of existing disturbance. With <br />the existing equipment fleet and any necessary replacement units, reclamation of all <br />existing disturbance areas would have taken approximately 9.0 to 10.0 years. <br />Although not required under the existing approved permit, Kerr leased additional <br />equipment to expedite final reclamation of Pit 1 and the 720 Pit. <br />Ongoing mining operations in Pit i resulted in removal of approximately 600,000 bcy <br />of overburden. This production overburden was direct hauled within Pit 1 and <br />backfilled in the southern and central portions of that pit. The northern portion of Pit 1 <br />was subsequently reclaimed by reestablishing effective drainage and grading highwalls <br />down to maximum 3.OH:IV slopes. In order to resolve outstanding AOC issues, Kerr <br />committed to and placed approximately 417,000 cy of supplemental backfill material <br />in the Pit 1 reclaim area. Kerr completed supplemental backfilling during the 1995 <br />field season, with soil replacement and revegetation following in the tall. <br />The general plan for backfilling and grading is shown on Map 33, Kerr Mine Area <br />Overburden Replacement and Grading. As can be seen from this Map, during active <br />mining in Pit 1, backfilling of the 720 Pit progressed at a steady rate using material <br />from the existing overburden stockpile. Map 33 indicates that backfilling, grading, and <br />revegetation in the 720 Pit progressed from multiple spoil dumps on the north and <br />south ends and center of the pit as opposed to the sequence under which it was <br />mined Inorth to southl. This sequence minimized haulage distances and gradients <br />from the existing overburden stockpile. <br />During active mining operations in Pit 1, Kerr established a reclamation target which <br />involved replacement of at least 300,000 cy of backfill material from the existing <br />overburden stockpile in the 720 Pit annually. With remaining mineable reserves of <br />approximately 200,000 tons in Pit 1 and projected contractual obligations, mining in <br />Pit 1 was completed in 3.0 to 3.5 years. Over this period approximately 1.1 million <br />additional cy of backfill were placed in the 720 Pit. <br />Upon completion of mining in Pit 1, Kerr planned to either commit to development of <br />Pit 2 or initiate full scale reclamation of existing disturbance. In either case, the <br />TR-19 780-68 Revised 1 1 /98 <br />