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' ALTERNATIVE 7
<br /> COMPLETE EXCAVATION FOR OFFSITE DISPOSAL GlEOMATRIX
<br /> PRELIMINARY COST ESTIMATE
<br /> . Former ContiGroup Grain Elevator
<br /> 1805 Harbor Street Page l oft
<br /> Stockton California
<br /> Assumptions
<br /> 1 Extent ofercavation encroaches on two dead-end railroad tracks Both spurs will be closed teaporanly for track removal,excavation and
<br /> ' backfill,and trackrep lace merit
<br /> 2 Excavation area s approximately 11,3 00-ft (110-ft x 140-ft) The top 10-ft ofoverburden soil to be removed,stockpiled,and tested
<br /> Overburden soil 4 200 cy assumed to be non-hazardous and used to backfill excavation Excavation depth is 30-f1 bgs and affected sod
<br /> volume is approximately 8,400 cubic yards(14,200 tons @ 125 lbs/ft'density)
<br /> ' 3 Excavation will be shored for 30-feet deep soil removal
<br /> 4 Groundwater depth approximately 12-ft bgs No buned utilities assumed
<br /> 5 Existing 14-ft x 20-ft concrete pad to be removed Assumed 6-inch thickness Concrete debris este ated at 12 5 tons to be recycled
<br /> 6 Existing asphalt pavement(4,500-ft2)to be removed Assumed 9-tach thickness Disposal ofasphalt debns at local recycle facility
<br /> 7 No confirmation sampling ofexcavation
<br /> 8 Shored excavation will be dewatered during excavation and backfill Assume dewatering extraction rate ofapproximately 25 gallons per
<br /> minute
<br /> 9 The extracted water will be piped to a treatment system consisting of two 2,000-pound carbon units arranged in series,pumps,sand filter,
<br /> holding tanks,water-level controllers,piping,and namfo ld The treated water would be discharged to a City sewer with permit
<br /> 10 For cost estimating purposes,the affected soil is assumed to be transported to the Class U Forward landfill in Stockton,CA fordsposal
<br /> Soil waste to be profiled based on existing soil data prior to excavation mobilization
<br /> 11 Import fill from local source placed to one-foot below bottom ofpavenment l2-inches ofaggregate based rock to be placed and
<br /> compacted to 95%relative compaction forpavement base
<br /> 12 Top 10-ft of stockpiled overburden soils to be sampled and analyzed for TPH-diesel and TPH gasoline One composite sample per 100c
<br /> ofsoil
<br /> 13 The conceptual design forths altemative(dewatermg carbon treatment system,demo,shoring,excavation,and re-construction)was
<br /> ' developed for cost analysis purposes only,additional evaluations will be necessary forthe final systemdesign ifths alternative is
<br /> irrple mented
<br /> 14 No air monitoring required
<br /> 15 No dust control orvapor suppressant required
<br /> • 16 Municipal watersupply available on-site
<br /> Notes
<br /> The following costs were estimated based on a conceptual design ofthe remedial action and readily available cost information on labor and
<br /> material typical for smularprojects The actual costs for this project may vary depending on the final design,contract bids agencies'
<br /> requirements,andlorthe availability ofequipmrent,materials and/or contractors at the time of fmal remedial action design,construction,
<br /> andlor implementation
<br /> TASK
<br /> ' ACTIVITY QUANTITY UNIT UNIT$ COST S SUBTOTAL$
<br /> PLANNING and PREPARATION
<br /> re-meld activities 135,000
<br /> ' utility protection design&approval I lump sum 15,000 15,000
<br /> stormwater permit 1 lump sum 5,000 5,000
<br /> properties access agreements 1 lump sum 25,000 25 000
<br /> workplan-excavation,demolition,stormwater,disposal 1 lump sum 75,000 75,000
<br /> ' surveying I lump sum 15,000 15,000
<br /> PLANNING and PREPARA TIONSUB TOTAL $ 135,000
<br /> DEWATERING and TREATMENT SYSTEM
<br /> re-tell activities 32,000
<br /> city encroachment permit 1 lump sum 10,000 10 000
<br /> city sewer discharge permit 1 lump sum 10,000 10 000
<br /> design treatment system,procure equipment 100 hr 100 10,000
<br /> underground utility locator 1 lump sum 2,000 2,000
<br /> install dewaterinz treatment_system 49,000
<br /> install piping,instrumentation,electrical controls 1 lump sum 20,000 20,000
<br /> dewatering pumps 2 ea 3,000 6,000
<br /> transfer pump 1 ea 1,000 1,000
<br /> fuel or electricity for pumps 1 ea 3,000 3,000
<br /> rental of holding tanks 1 lump sum 10,000 10,000
<br /> carbon system(2 pairs o€2,000-pound GAC) 1 lump sum 9,000 9,000
<br /> 14poc_Safeh900os599635CARAppB Alternatives As 1016/20049 53 AM
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