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5.0 WELL INSTALLATION ' Monitoring well installation can be broken into seven main steps • Packing the 1 0-mch x 2 5-inch OD Well Screen with sand • Driving the probe rods to depth ' • Deploying the screen and riser pipes • Installing a sand/grout barrier • Installing a bentonite seal above the screen • Grouting the well annulus • Installing surface protection Size and material options have resulted in an extensive list of Geoprobe part numbers To simplify the instruc- tions presented in this document,part numbers are listed in the illustrations only Refer to "Section 3 0 Re- quired Equipment" for complete part descriptions 51 Packing the 1.0-in x 2 5-in OD Well Screen with Sand The 1 0-inch x 2 5-mch OD Well Screen can he packed with sand before arriving at the job site or at the job site However, to help make the well installation pro- cess more efficient,Geoprobe Systems recommends pack- ing all well screens with sand before mobilizing to the job 3 25-in Drive Cap site Each box of I 0-inch x 2 5-mch OD Prepack Screens (9742 or 10605) comes with a complete set of sand filling instructions In- structions for filling the screens with sand are described in Section 4 0 52 Driving Probe Rods to Depth I Locate the Geoprobe probing machine over the proposed monitoring well Unfold the probe and place it in the 3 25-in Expendable proper probing position as shown in the unit Owner's Potnt Holder Manual Since access to the top of the probe rods is (13925 10599 ' required,it is important to allow room for derrick retrac- 9040) tion when positioning the unit for probing ' 2 Insert a 3 6-inch OD Expendable Point Assembly into the unthreaded end of a 3 25-inch Expendable Point Holder See Figure 5 1 ' 3 Place a 3 25-inch Drive Cap over the threaded end of the expendable point holder ' Expendable Point 4 Place the expendable point holder under the probe ham- 3 6-,n OD mer in the driving position (refer to unit Owner's (AT3215) Manual) Drive the point holder into the ground,using percussion if necessary To install an accurately placed monitoring well,it is important to drive the rod string as straight as possible If the point holder is not straight, FIGURE 5 1 retract the assembly from the ground and start over with Dnve Cap,Expendable Point Holder Step I and Expendable Point Assembly i Standard Operating Procedure Page 11 1 0-in x 2 5-in OD Prepack Screen Monitoring Well