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Page 6 <br /> DMG BID DOCUMENT <br /> TASK 2 SURFACE DRAINAGES <br /> (continued) <br /> The contour trench (Channel B) will be 200 feet in length, and 10 (10) feet <br /> wide and no less than four(4) feet in depth as measured from the base to the <br /> top of the cut on the inside of the excavation. Side slopes will not exceed <br /> 3HAV. The dozer will excavated this `L'shaped cut into the side slope of the <br /> refuse pile spoiling the cut material downslope. The contour trench will be <br /> excavated at the location staked in the field by the PROJECT MANAGER. The <br /> contour trench will be staked and excavated so that it follows the contour of the <br /> Sutey Refuse Disposal Area. <br /> An existing downdrain (Channel C) at the south end of the pile must be <br /> reconstructed. The drain will be 800 feet long, five feet wide at the base and <br /> the top of the side slopes will be no less than three feet above the down drain <br /> invert. Side slopes will not exceed 3H:1 V. Riprap with a median diameter(D- <br /> 50) of twelve (12) inches (maximum diameter not to exceed three feet) will be <br /> placed in the channel to a depth of at least eighteen (18) inches over a well <br /> compacted subgrade. After placement, the riprap surface will be worked to be <br /> well-graded with the voids choked with smaller cobbles and stones. A source of <br /> nprap within the mine site area will be identified by the CONTRACTOR, subject <br /> to approval of the PROJECT MANAGER. The material will consist of durable <br /> sandstone or metamorphosed shale materials. Unaltered Mancos Shale is not <br /> acceptable for riprap. <br /> Pages 6-7 <br /> DMG BID DOCUMENT <br /> TASK 5 EQUIPMENT RENTAL <br /> (continued) <br /> Portions of the Sutey Refuse Disposal Area require further final grading with a <br /> `dozer,'and erosion control work before commencing Task 3. Dozer basins may <br /> be constructed at the Number 5 Mine, or on the Sutey Pile or at the base of the <br /> structure to retain moisture for shrub establishment. Basin dimensions will <br /> approximate 2 dozer blade widths with a 48-inch depth. <br /> Page 9 <br /> Comments re. Channel A: The "diversion ditch" identified as Channel A <br /> combines clean-water runoff with water draining from the disturbed area. It <br /> violates a number of regulatory requirements. Among these: <br /> 4.09.2(7) Surface water runoff from the area above the fill shall be diverted <br /> away from the fill.... <br /> The Division plan for Channel A is inconsistent with prior Division policy that <br /> refuse piles must be protected from upland flows by a (clean water) diversion <br /> MCR Objections/DMG Bid <br /> Page 3 <br />