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_ e � <br /> it <br /> ` 12 February.1999 * " <br /> AGE=NC-Project No. 98 0540 <br /> h Page 6 of 8' s £ <br /> Following completion:of hollow-stem auger'dnllmg activities, a PVC two inch diameter Schedule <br /> 40 slotted well screen;(0 020=inch)azid:well casing will be installed <br /> x <br /> `ry The casing;filter pack and sealing matenals will be•.placed into the bo`reho]e through the intenor of ; <br /> the hollow-stern augeis After:instalhng'the well casing,,filter.pack material consisting of pre-washed`"� r <br /> 4 C _ �t <br /> } <br /> #2/12 Lonestar sand will be added from?tli6 bbadin-of the borehole to approximately twoifeet above , <br /> the screened interval.'Following placement of`the filter pack, the well will be.surged to assist m <br /> settling the filter pack: Additional sand will be added if settl ng occurs <br /> W. <br /> 1 g A nominal two foot bentonite seal will be::placed above the filter pack to minimize the potential of <br /> grout penetration into-the screened section of the well The bentonite seal will lie.fonned by pounrig <br /> bentonite`chips into the annulus and allowing them,to" settle on the filter pack.-Be 'to nitedhI' s <br /> ' <br /> be hydrated using five gallons of wate% The b`entomte chips,will be allowed to hydrate for a'- <br /> `' - minimum of,one-half h pnor to inserting the second well:casing <br /> The same installation procedures will apply for both the deep screened interval and the shallow w ' <br /> r rad _ : .- <br /> screened mterval.-Fo116 1 hydration ofbentonite clops,the remaining annular'space will be filled:: <br /> r to the ground.surface with a.cement grout. The grout mixture will consist of Type I/II Portland neat'.` <br /> f _ _ <br /> cement and snot more than 6 gallons of. per94-pound sack of cement The-grout will,be placed' r <br /> by pumping through tremmie pipe Proposed well`construction diagrams aze illustrated in Figures a p <br /> .3 and 4 Grouting procedures-will be"inspected by,PHS EHD personnel . <br /> r <br /> - � J ' L e 3:,. y <br /> Following completion:of the momtonng wells,well elevations and locations will be surveyed by a' `fi t ,• - <br /> ;; .'California-licensed surveyor <br /> �r 43 WEI L DEVELOPMENT <br /> F <br /> Ar <br /> r Development will' consist of a-combination ofbaihng and ground water pumping to remove the- <br /> ' ti major portion of fine=grained sediment':from inside the.well and surging to;flush out=or draw in'` <br /> .pa " sediment from the filter pack,'Developigent activities will.be continued until field parameter (pH;k <br /> r electrical conductivity; and temperature)'readmgs�have stabilized , r` e <br /> 42.--e•-„ g..� Shy,yf� F 1 <br /> y L <br /> { 4.4 ,;GROUNDWATER SAMPLING PROCEDURES <br /> j = Groundwater sample collection will be performed in-accordance with pertinent applicable sampling`, <br /> t T <br /> t _j protocols, details of which are.presented-below <br /> twr <br /> . s <br /> D 4 t <br /> 4 <br /> A <br /> � £ " r -- � .. Advanced CeoEnvtronmental Inc_.: <br /> q.• "k - X _ t ..t �� 3 a <br />