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STANDARD OPERATING PROCEDURE SOP-10 <br /> GROUND WATER MONITORING WELL CONSTRUCTION (fr <br /> Y <br /> f] <br /> The purpose of this Standard Operating Procedure (SOP) is to provide information on how to <br />' construct a ground water monitoring well using hollow stern auger drilling equipment Methods <br /> explained in this SOP may differ from those contained in a project specific Work Plan (WP) or <br /> Sample Analysis Plan (SAP), and the project specific WP or SAP should be consulted for <br />' modifications to the methods listed below <br /> WELL CONSTRUCTION <br />' The well will be constructed of flush threaded well casing material All well casing materials will <br /> be steam -8eaned prior to use The size of the well casing, e g , two-inch diameter or four-inch <br /> diameter, as well as the type of casing, e g , polyvinyl chloride or stainless steel, will vary <br />' depending upon the nature of the contaminants and the proposed use of the well <br /> The boring diameter will be at least six-inches larger than the well casing diameter The well will <br />' be constructed of a slotted section (the size of the slotting will vary depending upon the nature of <br /> the materials penetrated) which will extend ten to 20 feet below the water table and five feet above <br /> the highest anticipated fluid level In the event that a laterally extensive clay layer is encountered <br /> below the water table that is at least five feet thick, the well will be terminated one to two feet <br /> within the clay layer The annular space between the borehole wall and the well casing will be <br /> backfilled with the appropriate grade sand to approximately three feet above the slotted section A <br /> one-foot thick layer of hydrated bentonite will be placed on top of the sand pack, and the <br /> remaining annular spaced grouted to the surface using a 10 1 ratio of cement to water with three to <br /> five percent bentonite Lockable well monuments flush with the ground surface or an aboveground <br /> type will be placed on all wells See attached cross sectional view of a typical ground water <br /> monitoring well <br /> The well will be allowed to set after construction for at least 48 hours, prior to initiating <br /> development activities The well will be developed until the water is relatively free of settleable <br />' solids <br /> SAO HASP SOP 10 <br /> r <br /> Revised February 7994 1 ENWRONMEVTAL AUDIT, INC o <br />