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Mr. Harlin Knoll Project No. 2007-065-01 <br /> April 28, 2000 <br /> Page 4 <br /> foot seal consisting of bentonite pellets. Cement grout containing 5 percent bentonite will <br /> be placed above the bentonite seal to the ground surface. A watertight locking cap will then <br /> be installed over the top of the well casing and a flush-mount traffic-rated vault box installed <br /> over the well. Further details regarding the installation of the monitoring wells are presented <br /> in Appendix A. <br /> Task 3 Destroy Monitoring Well MW-5 <br /> Monitoring well MW-5 will be destroyed in place by pressure grouting with neat cement <br /> slurry. Prior to any fieldwork, the volume of grout needed to fill the casing and <br /> associated sand filter pack will be calculated. Approximately 11-13 pounds of Type II <br /> Portland cement will be mixed per gallon of water to form the grout. The grout will be <br /> placed in the well with a trimie hose from the bottom of the well to the surface. <br /> Additional grout will be added to the well upon settlement of the initial grout. Actual <br /> volume of grout used will be recorded in a field data sheet. The monitoring well box will <br /> be removed and the surface will be finished to match the surrounding surface. <br /> Task 4 Develop and Sample Monitoring Wells <br /> Development of the monitoring wells will consist of surging with a surge block and <br /> pumping. Development will continue, to the extent practical, until the development <br /> water runs clean and pH and conductivity measurements stabilize. After well <br /> development and stabilization of the water levels, Stratus will record water levels and <br /> measure the number and quantity of well volumes removed from each well, which will be <br /> recorded and included in the investigation report. <br /> After waiting a minimum of 24-hours after development, Stratus will purge and collect <br /> water samples from each well and forward the samples to a state-certified analytical <br /> laboratory. Purged water will be stored onsite in 55-gallon drums. Appendix B presents <br /> the procedures associated with development and sampling of the monitoring wells, <br /> including chain-of-custody and sample handling procedures. <br /> The groundwater samples will be analyzed for total petroleum hydrocarbons as gasoline <br /> (TPHG), and benzene, toluene, ethylbenzene and xylene isomers (BTEX) using U.S. <br /> Environmental Protection Agency (USEPA) Method 8015/8020 Modified, and for <br /> oxygenates (including Methyl Tertiary Butyl Ether [MTBE], Ethyl Tertiary Butyl Ether <br /> [EtBE], Diisopropyl Ether [DIPE], Tertiary Amyl Methyl Ether [TAME], Tertiary <br /> Butanol, Tertiary Butyl Alcohol [TBA], and 1,2-Dichloroethane (1,2-DCA) using <br /> USEPA Method 8260. <br /> Top of casing elevations and horizontal coordinates will be surveyed by a licensed land <br /> surveyor to an accuracy of 0.01 foot vertical and 0.1 foot horizontal. All elevations will <br /> be tied to a United States Geological Survey bench mark. <br /> C:165wrkpin.doc Stratus <br />