2011-03-01_REVISION - M1977493 (6)

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Permit Amle (AM-06) - Climax Mine 0 CLIMAX MINE RECLAMATION COST ESTIMATE Financial Reporting Unit Rates Tenmile Tunnel Sealing + Bulkhead Construction • Assumptions: (1) Cost of bulkhead work in 2003 and 2004 can be used to pro-rate costs for final closure; (2) Tunnel will be maintained until closure such that it is accessible at least as easily as it is today; (3) Hydrostatic pressures are such that a bulkhead at both ends + sludge and check dams in between will effectively "maintain" the integrity of the tunnel indefinitely; 220' head at closure per T. Rogers 2/8/2010. (4) Even if it should collapse, the fact that drainage would be captured in the Climax Water Treatment System would prevent discharge of contaminated waters. Tasks: (1) Build bulkhead on north end of tunnel near opening to act as a dam; $80,000 per T. Rogers 2/8/2010. (2) Pump tailing from Tenmile OSF into tunnel to accumulate against north bulkhead; (3) Build 4 bulkheads at locations spaced approximately 2,000 ft apart to capture liquid sludge; $80,000 ea. per T. Rogers 2/8/2010. (4) Continue pumping until tunnel will take no more sludge; (5) Seal south end of tunnel with bulkhead; $80,000 per T. Rogers 2/8/2010. Timing End of Mine Life Total Cost $789,264 Calculations Task/Area Qty Units Adj Qty Units Total Equip Cost/Unit Total Labor Cost Cost/Unit Total Material Cost Total Cost Cost Labor Materials What is the length of the Tenmile Tunnel? 10,500 feet What is the height of the Tenmile Tunnel? 10 feet What is the width of the Tenmile Tunnel? 10 feet Calculated Volume of the Tenmile Tunnel = 1,050,000 cu ft 38,889 cu yds What is the length of a bulkhead plug for north end? 50 feet Calculated volume of concrete to build plug = 185 cy What is the length of a bulkhead plug for south end? 50 feet Calculated volume of concrete to build plug = 185 cy What was the total cost of bulkhead built in 2008? $ 90,000 What was the length of the bulkhead built in 2003? 18 feet Calculated cost per foot for 2003 bulkhead = $ 5,000 $/ft Calculated unadjusted cost for closure bulkheads = $ 1,175,926 Cost reduction expected based on better access? 50 % Adjusted cost for closure bulkheads = $293,981 $146,991 $146,991 $ 587,963 Check using concrete costs for work by Nielsons 2005 What was the cost for concrete work at Robinson? $ 1,430 $/cy inflated to 2008 $ Applying Nielsons cost to closure bulkheads = $ 529,702 by Nielsons for comparison to cal culated value What is volume of Robinson Lake Sludge to Pump? 38,519 cy What is cost per cu yd to pump sludge into tunnel? $ 6.60 $/cy inflated to 2008 $ What is cost for mob & demob of dredging equipment? $ 55,008 inflated to 2008 $ Calculated cost to dredge and pump sludge to tunnel = $ 254,257 Total cost of dredge+pumping+mob/demob = $154,632 $77,316 $77,316 $ 309,264 What is the estimated cost to build one bulkhead? $ 2,200 inflated to 2008 $ What is the total number of bulkheads to build? 4 Total cost of "check dams" _ $4,401 $2,200 $2,200 $ 8,801 Total Equip Cost Total Labor Cost Total Material Cost Total Cost TOTAL COSTS $ 453,014 $' 226,507 $ 226,507 $ 789,264 Exhibit L Feb 2011