Laserfiche WebLink
<br />Preliminary Drafr <br />Financial Warrurty Requirement Re-evaluation <br />San Luis Project M-88-112 <br />January 31, X000 <br />TASKS AND COST ESTIMATES FOR REMAINING RECLAMATION <br />OBLIGATIONS: <br />WEST PIT WATER MANAGEMENT PROGRAM <br />ASSUMPTIONS: <br />In order to clean up the West Pit backfill, the operator needs to withdraw and process <br />5.229 pore volumes of water from the aquifer as calculated and presented in the attached <br />Shepherd Miller Inc. (SMI) Technical Memorandum -Revised [~Ves[ Pi[ Pore %lume <br />Calculct[ions. <br />1 pore volume equals 132,»3,000 gallons as calculated and presented in the a.[ached <br />SMI Teclaucal Memorandum-Revised Guest Pit Pore Yblume Culculalions. <br />5.229 pore volumes times 132,53,000 gallons equal 693.120,000 gallons. <br />2 processes and 1 alternative have been evaluated by Tecturical Revision (TR) 26. <br />Therefore, these processes are the only available options for evaluation. These processes <br />include: <br />A) Active Water Treatment (Membrane Separation) <br />B) Enhanced Mechanical Evaporation <br />For purposes of this evaluation, the active water treatment (membrane separation) process <br />is the only process evaluated. The estimated long-term membrane separation cost equals <br />$6.90/1,000 gallons treated as quoted by ERNor[hwest [nc. of Englewood, Colorado. <br />The West Pit water level will be pumped down approximately I S feet (to a msl of 8,580 <br />feet) at a pumping and treatment rate of 400 gpm. Thereafter, the aquifer will be <br />pumped and treated at a steady-state rate which is estimated a[ 180 gpm. The 5.229 pore <br />volume calculation presented by SMI does not differentiate between the initial reduction <br />phase pump and treat activities and the steady-state pump and treat rate. Therefore, the <br />volume calculation presented by SMI is the total predicted volume required to ~e <br />extracted from [he West Pit groundwater system. <br />SMI's pore volume predictions were prepared using West Pit groundwater water quality <br />concentrations from November 1999, since this time the operator has removed additional <br />water from the West Pit groundwater system. This quantity of water removed i <br />10.893,300 gallons of groundwater. <br />It will t•ilce approximately 7.25 years to pump and treat 5.229 pore volumes of ,eater at an <br />extraction pumping rate of 180 gpm. This is based on 693,120,000 gallons minus what <br />