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1.0 OBJECTIVE <br /> The objective of this procedure is to install a permanent,small diameter groundwater monitoring well that can <br /> be used to collect water quality samples,conduct hydrologic and pressure measurements,or perform any other <br /> sampling event that does not require large amounts of water at any given time <br /> 2.0 BACKGROUND <br /> ' 21 Definitions <br /> Geoprobe®Soil Probing Macbine: A vehicle-mounted,hydraulically-powered machine that uses static <br /> ' force and percussion to advance small diameter sampling tools into the subsurface for collecting soil <br /> core, soil gas, or groundwater samples The Geoprobe brand name refers to both machines and tools <br /> manufactured by Geoprobe Systems, Salina, Kansas Geoprobe tools are used to perform soil core and <br /> soil gas sampling,groundwater sampling,soil conductivity and contaminant logging,grouting,materials <br /> injection,and to install small diameter permanent monitoring wells or temporary piezometers <br /> 1.0-in x 2.5-in. OD Prepack Well Screen- This Geoprobe well screen is available in 5-foot (1,5 m) <br /> t sections with a 1 0-inch(25,5 mm)inside diameter(1D)and a 2 5-inch(63,5 mm)outside diameter(OD) <br /> The inner component of the well screen consists of 1 0-inch Schedule 40 PVC with 010-inch (25 mm) <br /> slots The outer component of the screen is stainless steel wire <br /> mesh with a pore size of 0 011 inches These screens are <br /> shipped without sand and are designed to be packed with 20- Plasbc Plug <br /> 40 grade silica sand before installation (13227) <br /> 1 40 PVC <br /> 22 DI5Cu55lOn Riserser Pipe <br /> (12876) <br /> This procedure describes the installation of a permanent mons- t <br /> tonng well using I 0-inch x 2 5-inch OD prepack well screens, <br /> a Geoprobe percussion probing machine, and Geoprobe tool- <br /> ing Well installation begins by using a Geoprobe percussion <br /> probing machine to advance 3 25-inch OD probe rods to a pre- <br /> determined depth Next,the prepack well screen is assembled <br /> and lowered through the 2 625-inch ID of the probe rods The ep Pipe x 2 min o� <br /> t� <br /> process continues by installing a grout barrier, grouting the (11679) <br /> well annulus while retrieving the probe rods, and installing a <br /> surface cover After installation, the well is developed and <br /> water samples are collected These wells may also be used to <br /> conduct slug tests or as observation wells during pumping tests 1 0-in Pipe x 2 5 m oR <br /> Prepack <br /> to determine aquifer parameters (11679) <br /> As mentioned above, well installation begins by advancing <br /> 3 25-inch OD probe rods to a predetermined depth with a PVC Bottom Plug <br /> Geoprobe percussion probing machine Once the rods are set (12881) <br /> at depth,the prepack screen is lowered through the 2 625-inch <br /> (38mm)ID of the probe rods on the leading end of a PVC riser A5 )e Pant 3 s m oC <br /> string (Fig 2 1) After the prepack is lowered to depth, the <br /> probe rods are retracted As the rods are retracted above the FIGURE 2 1 <br /> screen,either natural formation collapse or a fine-grade sand Insertion of Prepack Screens <br /> Standard Operating Procedure Page 3 1 0 in x 2 5-in OD Prepack Screen Monitoring Well <br />