1991-04-11_GENERAL DOCUMENTS - C1981031

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Calculated volumes of overburden ( "placed cubic yards") to complete pit backfill ing thusly are: PIT OVERBURDEN FROM PILE C REQUIRED PIT 1 10 ,850 cy PIT 2 18,450 cy PIt 3 18,900 cy b) Subsoil Following the backfilling of pits with overburden , stockpiled subsoil from PILE A will be mounded above each pit at a volume equal to approximately 5% of the total pre-backfilling volume of each pit. This will provide positive drainage and will compensate for settling. Subsoil from PILE A will be distributee over backfilled pits according to the schedule below. This will utilize all 3 ,500 cubic yards of material in PILE A. Subsoil material will be placed in maximum 2 foot lifts and each individual lift will be wheel compacted. Total estimated volumes of material ("placed cubic yards") required to complete backfilling of existing strip-pits with coal spoil , overburden , and subsoil is as follows: PIT COAL SPOIL OVERBURDEN SUBSOIL TOTAL (105%) (cy) (cy) (cy) (cy) PIT 1 5,400 10 ,850 1 ,000 17 ,250 PIT 2 8,200 18 ,450 1 ,300 27 ,950 PIT 3 3,400 18 ,900 1 ,200 23,500 1/ ,000 48,200 3 ,500 68 ,700 The CONTRACTOR will note that the above mentioned volume figures are for "placed yards of material " and do not include a swell factor. A determination of actual moved volumes of material should be calculated by the CONTRACTOR prior to his bid calculations. Submittal of the CONTRACTOR'S calculations is not required. The material to be moved on this project has an estimated swell factor of 15-20% based on previous jobs and from general experience . The CONTRACTOR will bear in mind that this figure may be inaccurate since no swell/compaction tests have been run to date on this material The backfil 1 ing of pits with overburden and subsoil must be approved by the PROJECT MANAGER at completion. (- c) Grading 5 o I h0 owe ��r2 yek-3 6 vk al/de Upon compl eti on of all strip-pit backfill ing, the CONTRACTOR will perform work as necessary to achieve a gently undulating topography across the entire project area disturbed by our project activities . All slopes will be reduced to 5:1 (horizontal:vertical ). Material remaining in PILE C will be left in an even profile with slopes not to exceed 5 :1 (horizontal:verti cal ). The existing drainage berm at the east toe of PILE C, which directs surface run-off from this pile to a small sediment pond at the north end of the project area, will remain functional . -8-