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•Ms. Candace Thompson <br /> November 26 , 1986 <br /> Page - 5 <br /> This would require the cost calculations to be computed <br /> on four times the number of hours that would be required under <br /> the equipment' s unadjusted production ratings. As was mentioned <br /> previously, our experience in Coal Basin has been that D-8 dozers <br /> with turbo charged engines are very efficient. In our cal- <br /> culations for the mine pad backfilling we doubled the number of <br /> hours (50% efficienty� for most of them to account for slight <br /> uphill grades , types of material, etc. We do not believe it <br /> reasonable to accept a 75% reduction in dozer efficiency on the <br /> mine portal pads . <br /> MLRD is correct in their observation that Mid-Continent <br /> did not include storage pads 3 and 4 associated with Mines 1 <br /> and 2 in our backfilling estimates . Those storage areas are <br /> included in the total disturbed area calculations for each <br /> of the mine portal areas . They are part of the 7 . 7 acres of <br /> disturbed areas credited to the Mine No. 2 portal area, and <br /> for which topsoiling and revegetation have been included. We <br /> do need to add the cost of backfilling. From the attached <br /> cross-section of the number 3 storage bin pad which has a <br /> surface area of approximately 1/2 acre we calculate that 10 ,000 <br /> cy, yds of materials would need to be pushed an average of 200 ' <br /> at a 10% uphill grade. We have previously established that <br /> a D-8 dozer can optionally push 500 CYH this distance. Reducing <br /> this by half for realistic correction factors it becomes <br /> 250 CYH. <br /> 10 , 000 Cy Yd <br /> 250 CYH = 50 Hours <br /> 40 Hours x 118 $4 , 720 <br /> For the number 4 storage area very little backfilling <br /> and grading is required, or possible. The one acre area is <br /> on the top of a relatively flat ridge where only a small <br /> amount of grading was required to establish it originally. Only <br /> on the north side is there a recognizable outslope fill. It <br /> has become well revegetated and should not be re-disturbed. A <br /> small cut bank of about 5 or 6 feet height exists at the east <br /> side of the area and should be cut back to at least a 3 to 1 <br /> slope. Four hours of D-8 dozer time will more than accomplish <br /> the required backfilling and grading of this area and the <br /> push distance is 50 ' or less. <br /> 4 Hrs. x 118 ^ $472 for area 4 <br />