WORK PLANS - Laserfiche WebLink

Home Browse Search

A complete description of the guidelines that are to be used for the installation of filter pack material is presented in the Comprehensive Field Work Plan(Radian International, 1998). 4.4 Bentonite Seal Each monitoring well will be constructed with a bentonite seal placed above the filter pack to protect the filter pack during grouting.The bentonite seal will consist of bentonite pellets or chips. Once the seal is in place,the interval will be hydrated for a minimum of 30 minutes, before grouting occurs.Guidelines that are to be used for the installation of the bentonite seal are presented in the Comprehensive Field Work Plan (Radian International, 1998). 4.5 Cement Grout A cement grout will be used to fill the annular space above the hydrated bentonite seal.Cement grout will consist of Type 11 Portland cement with 3 pounds of powdered nonbeneficiated bentonite and 7 gallons of water per 94-pound sack of cement.The cement grout will be mechanically mixed with a paddle type mixer and then tremied in place.No accelerator will be added to the grout.Guidelines that are to be used for the installation of the grout seal are presented in the Comprehensive Field Work Plan(Radian International, 1998). 4.6 Wellheads Once each well's grout seal has been tremied into place and time has elapsed to allow for the grout to cure, a watertight,Christy G12 Traffic box or equal,will be paced over the top of each well. A schematic of the well box is presented as an attachment at the end of this document. All of the nine wells will be completed flush with the ground surface. 5.0 POST WELL INSTALLATION ACTIVITIES 5.1 Monitoring Well Development Each well will be developed after well casing installation.Well development procedures will follow those outlined in the Comprehensive Field Work Plan(Radian International, 1998).Wells will be bailed with a sand-pump bailer to remove fine sand inside the well casing;bailing will continue until fine grained sediment removed from the well decreases to less than an estimated volume of one ounce of sediment in one bailer load.The well will then be surged for at least 30 minutes or until the amount of sedimept entering the well decreases to a level deemed acceptable to the field geologist.Well development data recorded will include field determinations of pH, temperature, specific conductivity,turbidity data,the total number of well volumes purged from the well during development,and the average pumping rate during development. 5.2 Well Location Surveying The top casing elevation will also be measured for each of the newly installed monitoring wells.Horizontal coordinates will be determined to the closest 1.0-foot and referenced to the State Plane Coordinate System, Zone 3,North American Datum of 1983.Ground and top of casing elevations to the closest 0.1-foot and 0.01-foot,respectively,will be obtained at each well.These elevations will be referenced to the National Geodetic Vertical Datum of 1988.