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direction at that depth The proposed location of this monitoring well is shown on Figure 4 Since a CPT boring will have been drilled in this location, the bottom of the augers will be plugged with a wooden plug and no soil samples will b e collected The reason for this procedure is that flowing (heaving) sands have been previously encountered at this site from these depths a n d drilling problems in these conditions can be greatly minimized if the bottom of hollow-stem augers is plugged until the total depth is reached The well will be constructed within the hollow stem augers using 2-inch diameter flush-threaded, schedule 80, 0 020-inch slotted PVC well screen and blank casing The well casing will be lowered through the augers and #2112 filter pack sand will be placed in the annular space between t h e well casing and the borehole from the bottom of the boring to approximately 2-feet above the screened interval The well will b e developed using a surge block and bailer to settle the sand prior t o placing the sanitary seal Well development water will be contained in 55- gallon 5- gallon steel drums, labeled and stored on-site until proper off-site disposal can be arranged Approximately 1 to 2-feet of time release bentonite pellets will be placed on top of the sand pack prior to placing the cement sanitary seal Cement mixed with 3 to 5 percent bentonite powder by volume will be used to fill the annular space between the bentonite layer and the surface to prevent surface water from infiltrating into the well and to prevent conduits for the migration of contamination from shallow groundwater into deeper zones The cement will be placed by tremae pipe in all situations where the seal is placed below the water table The well head will be protected with a locking well plug beneath an at-grade, traffic-rated well box (See Figure 5 - Typical Monitoring Well) The monitoring well will have a screen no longer than 15-feet in length, and will have only one screened interval Since the CPT boring has not yet been completed, the exact well construction is not yet known but it is anticipated that the well will be screened between approximately 100 or 105 and 115-feet bgs TASK 5 - DRILL TWO SOIL BORINGS TO A DEPTH OF 19-FEET BGS AND INSTALL GROUNDWATER MONITORING WELLS IN THESE BORINGS ASE will drill two (2) soil borings at the site to approximately 19-feet b s using a hollow-stem auger drill rig for the installation of monitoring wells Frank's One Stop Workplan — June 2000 -13-