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At Mine 4, material will be excavated from the north and east facing bench outslopes (Map <br /> 4, Mine 4 Topography), and will be removed as uniformly as possible across the face of the <br /> outslopes. The CONTRACTOR shall excavate materials from the mine bench outslopes so <br /> that the downslope extent of the excavation maintains as uniform an elevation as is possible. <br /> Excavation shall proceed so that the excavated portion of the outslopes do not exceed 2H:1 V <br /> upon completion of the task. <br /> The excavated material shall be transported from the crest of the fill to the base of the <br /> highwall and placed over the rubble fill and mine bench remnant. The debris and rubble fill <br /> placed during Task 2, Demolition, shall be covered by a minimum of four (4) feet of backfill <br /> material during this portion of the project. Upon completion of the task, the top of the fill will <br /> extend thirty (30) feet above the highwall bench remnant. The PROJECT MANAGER will mark <br /> the thirty (30) foot level in the field using paint or other suitable materials. This thirty (30) <br /> feet backfill height will be maintained for the length of the highwall, except where reduced <br /> by the PROJECT MANAGER. Reduction of the backfill height is anticipated at the northern <br /> and southern portions of the highwall remnant, as the bench area narrows. The highwall is <br /> approximately 525 feet in length. The fill shall be compacted in six (6) foot lifts by a sheep's <br /> foot roller. Upon completion of backfilling and grading,the outslope of the fill shall not exceed <br /> 2H:1 V. <br /> Six (6) contour furrows two (2) feet wide and eighteen 0 8) inches deep will be constructed <br /> on the bench remnant to contain runoff in order to help prevent drainage from flowing both <br /> toward the toe of the fill and toward the mine bench outslope. These furrows are described, <br /> and will be constructed and paid for, under Task 5, Surface Drainage. <br /> Upon completion of backfilling, grading and furrow construction, the bench remnant shall be <br /> ripped to a depth of eighteen (18) inches. <br /> Task 41b - Lower Bench Area <br /> The Lower Bench Area, Task 4b, will receive a treatment similar to that at the Mine 4 <br /> highwall. After placement of silt fence, as directed by the PROJECT MANAGER, material will <br /> be excavated from the northerly facing outslope at the Lower Bench Area in order to achieve <br /> partial highwall elimination and outslope reduction. The CONTRACTOR shall excavate <br /> materials as uniformly as possible across the face of the lower bench area outslopes so that <br /> the downslope extent of the excavation maintains a relatively uniform elevation. Excavation <br /> shall proceed so that the excavated portion of the outslopes do not exceed 2H:1 V upon <br /> completion of Task 4. <br /> The excavated material shall be transported to the base of the highwall and placed in six (6) <br /> foot lifts, and compacted by sheep's foot roller. Upon completion of the task, the top of the <br /> fill will extend twenty (20) feet above the highwall bench remnant. The PROJECT MANAGER <br /> will mark the twenty (20) foot level in the field using paint or other suitable materials. This <br /> twenty (20) feet backfill height will be maintained for the length of the highwall, unless <br /> otherwise reduced by the PROJECT MANAGER near the margins of the highwall. The length <br /> of the highwall is approximately 185 feet. Upon completion of backfilling and grading, the <br /> outslope of the fill shall not exceed 2H:1 V. <br /> 9 <br />