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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 /> 2.1 Definitions <br /> Geoprobe®Soil Probing Machine: 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 /> ' sections with a 1 0-inch(25,5 mm)inside diameter(ID)and a 2 5-inch(63,5 mm)outside diameter(OD) <br /> The inner component of the well screen consists of I 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- (1322 Plug <br /> (13227) <br /> 40 grade silica sand before installation <br /> 1 40 PVC <br /> 2 2 Discussion Riserser Pipe <br /> {12876} <br /> This procedure describes the installation of a permanent moni- <br /> toring well using 1 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 1 0-in Pipe x 2 5-in OD <br /> and lowered through the 2 625-inch 1D ofthe probe rods The Prepack <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 /> I water samples are collected These wells may also be used to <br /> conduct slug tests or as observation wells during pumping tests 1 vein Pipe x 2 5 in OD <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 1D of the robe rods on the leading end of a PVC riser Expendable Pant 3 6-in OD <br /> ( ) p g (AT3215) <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 /> IStandard Operating Procedure Page 3 1 x 2 5-m OD Prepack Screen Monitoring Well <br />