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SFp-18-1997 1246 HRRDItIG LRWSON <br />Page Seven <br />Mr. Norm Every <br />Mountain Coal Company <br />801 363 aa76 P.08 <br />Harding Lawson ASSOCiates <br />Reliability is also relatively high as these systems are commonly tested during <br />construction so that their capacities are physically verilied and confirmed at the time of <br />installation. The biggest risk to these systems is the element of corrosion over the long <br />term, weakening and reducing capacities of the steel componrnts. <br />Initial capital costs aze very high, however operating costs are virtua}ly non-existrnt. <br />These systems would have a relatively higlt life and could easily attain a design life of 25 <br />to 30 years in an environment which is not highly corrosive. <br />Maintenance on such systems would also be minimal. <br />4.0 COMPARISON OF VIABLE ALTERNATIVES <br />The mitigation alternatives discussed in Section 3 above will be compazed acing abenefit- <br />cost ration "index°. The benefit side of the equation is determined acing the va]ue of the <br />facilities protected multiplied by a "risk" factor which is the product of an effectiveness <br />number expressed as a percentage (i.e., a number between 0 and 1) and a reliability <br />number, also expressed as a percentage. The cost side of the equation is determined using <br />the estimated capita! cost for construction plus the estimated annual maintrnaace cost over <br />the expected life of the facilities being protected (implicit in this equation is the <br />assumption that any altemative which is expected not to have a life or duration sufficient <br />to protect the facility over its useful life will already have been rejected as not feasible). A <br />ratio greater than 1.0 implies that a high probability exists that the cost of mitigation will <br />be less than the replacement cost of the facility. A ratio less that one implies that a high <br />probability exisu that the mitigation cost will exceed the replacement cost of the facility. <br />lmplicit in this interpretation is the assumption that if a mitigation alternative is likely to <br />fail or at least fall short of expectations (due to low effectiveness or low reliability). that <br />additional monies would have to be spent nn additional mitigation, facility repair, or both. <br />The following estimates of facility value wore used in this evaluation: <br />• Crushing/sc:reening plant, silos, and conveyor 56,000,000 <br />• Mine buildings 3 at E1,500,000 ea. S4,SOU,000 <br />• Ponds 2 at S 250,000 ca. S SOO,000 <br />• Loadout 1'aciliry 55,000,000 <br />• Lower ponds <br />2 at $ ZSO,000 ea. <br />5 500.000 <br />52.000,000 <br />$1,000.000 <br />$ 500,000 per day <br />• Misc. structures and facilities <br />• Reconstruction of ports! access if required <br />• Value of production loss <br />