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Delta Sand end Greve. • <br />PIT +Y1 Amendment <br />M.L.R.B. k M-77-020 <br />July 14, 1997 <br />PUMPING COST ANALYS/S <br />These pumping cost calculations are bused on some basic operating procedures common <br />to the industry and from data supplied by one of the largest pump supply houses on the <br />western elope. Awe understand the regulations, if th9 Division were to have to reclaim <br />the pit they would do it on the low bid, performing the work the easiest way possible end <br />nt the lowest cost. <br />The cheapest way to de-water the pit would be to place the largest pump possible in <br />the lake and pump it down in the shortest period of time possible. To do this we have to <br />make some valid assumptions based on the current conditions and industry standards and <br />practices being used now. <br />• An electrical pump would be used since there is a power line to the operation et <br />this time and it is en asset for the land owners to keep it if mining ceased. <br />• The use of n 3,000 gallon per minute (GPM) pump is typical for this initial drew <br />down. This ie within in the existing NPDES permit limits we currently have. Our <br />typical discharges from this site during pump down activities is 1.5 to 2.6 million <br />gallons per day (MGD). <br />• Beckfilling ie a cut/fill operation, the important elopes are the 3h:ly elopes, so <br />pertielly dewetering the pit is practical since it is coamron knowledge that grovel <br />pushed into water tends to create 2~h:ly elopes or less. <br />• An accurate estimate of the pumping coats come from actual date collected from the <br />current electrical bills, pump rental information and operating costa at the site at <br />this time. <br />Our proposed dewetering coats ere based on pumping the upper 14 feet of the lake so the <br />3h:ly underwater elopes could be created. By pertielly pumping the pit you decrease the <br />project time end cost and still complete reclamation to the underwater elopes ae required <br />by the law. <br />To figure the water volume in the excavated area we calculated the volume of water <br />on the slopes end added the cubic volume of water in the non elope area. The areas found <br />on the elopes are shown on the typical cross-section at the bottom of the cost estimate <br />page. We used a transmissibility rote of 117,000 GPD which was provided by the Division <br />during bonding calculation for another of our mining operations across the river. When <br />these numbers are added to gather you can come up with a number that represents the amount <br />of water hue to be pumped to complete the eloping. <br />The 3h:ly elopes can then be created end the lower elopes will form naturally as the <br />cut/fill process progresses, Review of the following sheets will explain the numbers we <br />used to find the total coat end hourly coat used in the bond calculation. <br />PUMP DATA'-~ <br />BERKELEY PUMP - Model BBGPBM, <br />with electric motor (40hp, 1800 rpm, 48 volt) includes pump control station, <br />inlet and discharge hoses. <br />CAPACITY - 3,000 GPM E 35 ft. of hand <br />SOURCE - Munro Supply, Grand Junction, CO. <br />RENTAL RATE - $1,912 per month <br />POWER SUPPLY <br />ELECTRIC MOTOR (40hp, 1800 rpm, 46 volt) <br />ESTIMATED OPERATING COST - $1,320 per month <br />TOTAL OPERATING COST PER MONTB $ 3,232.00 <br />AV6RAliti OPERATING COST P6R DAt ¢ 107.73 <br />13 <br />